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  • 1
    Electronic Resource
    Electronic Resource
    Einflüsse purinreicher Ernährung auf Gewichtsentwicklung, Kataboliten im Blutplasma und den Harnsäuretransport von Erythrozyten — eine Modellstudie an Hunden (1990)
    Springer
    European journal of nutrition 29 (1990), S. 135-146 
    Details
    ISSN: 1436-6215
    Keywords: purinreiche Nahrung ; Wachstum ; Metaboliten ; Harnsäuretransport ; Hund ; purine-rich diet ; growth ; metabolites ; uric acid transport ; dog
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary In a nutritional tolerance study 36 young dogs were fed over 52 weeks high or low purine diets at an average paired feeding intake of 0.6 and 80 mg purine-N/MJ per day. The high purine diet resulted in a significant decrease of growth rate by −23 % (Beagles) and −38 % (Dalmatians) and of feed efficiency (−29 and −42 %). The fasting levels of allantoin, uric acid and uracil in blood plasma were significantly increased. During the experiment a metabolic adaptation to the high purine diet decreased the plasma concentrations of uric acid, uracil and in part of allantoin. The high purine diet effected a significant increase of Km (2.5-fold) and of Vmax (1.6-fold) of uric transport through the erythrocyte membrane. The results documented disadvantageous effects of high purine nutrition during juvenile development.
    Notes: Zusammenfassung In einer Verträglichkeitsstudie erhielten 36 junge Hunde über 52 Wochen eine purinreiche oder purinarme Diät mit durchschnittlich 6 bzw. 80 mg Purin-N/MJ pro Tag bei gruppengleicher Aufnahme („paired feeding“). Die Hochpurin-Diät führte zu einer signifikanten Verminderung der Gewichtsentwicklung um −23% (Beagles) bzw. −38% (Dalmatiner) und der Futterverwertung (−29 bzw. −42%) sowie zu einer signifikanten Erhöhung der Nüchternwerte von Allantoin, Harnsäure und Uracil im Blutplasma. Während der Versuchsdauer machte sich eine metabolische Adaptation an die Hochpurin-Diät mit signifikanter Erniedrigung von Harnsäure, Uracil und teils auch Allantoin im Plasma bemerkbar. Die Hochpurin-Diät bewirkte eine signifikante Zunahme der Km (2,6fach) und Vmax (1,6fach) des Harnsäuretransports durch die Erythrozytenmembran. Die Ergebnisse belegen nachteilige Effekte purinreicher Ernährung während der Jugendentwicklung.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02021669
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  • 2
    Electronic Resource
    Electronic Resource
    Partitioning of fat and protein in energy retention of growing animals (1997)
    Springer
    European journal of nutrition 36 (1997), S. 299-302 
    Details
    ISSN: 1436-6215
    Keywords: Energy retention ; protein retention ; fat retention ; growth ; body composition ; broilers ; Energieansatz ; Proteinansatz ; Fettansatz ; Wachstum ; Körperzusammensetzung ; Broiler
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Mit steigender Aufnahme erhöht sich der Körperfettgehalt und der Körperproteingehalt nimmt ab. Es wird oft angenommen, daß jede Zunahme im Ansatz mit mehr Fett und weniger Protein verbunden ist. Experimentelle Ergebnisse widerlegen jedoch diese Annahme. In zwei Experimenten mit männlichen Broilerhühnern wurden die Tiere auf einem Niveau von 60 % und 100 % der empfohlenen Energieaufnahme gefüttert. Die Körperzusammensetzung bei 1500 g zeigte, wie erwartet, daß sich bei steigenden Aufnahmen der Körperfettgchalt vergrößert und der Körperproteingehalt abnimmt. Fettund Proteinansatz waren linear mit der totalen Energieretention (ER) korreliert. Das bedeutet, daß jede Zunahme im Ansatz den gleichen Protein- und Fettgehalt besitzt. Wenn der Fettansatz gleich Null ist wird nur Protein, etwa 50 % des maximalen Ansatzes, retiniert. Wenn ER=O ist, wird Protein angesetzt und Fett mobilisiert. Energie-und N-Bilanzuntersuchungen bestätigen die konstante Zusammensetzung jeder Vergrößerung des Ansatzes. Die Ergebnisse beider Experimente zeigen, daß die ER aus zwei Komponenten besteht: einem basalen konstanten täglichen Proteinansatz und einer variablen zusätzlichen ER, die hauptsächlich aus Fett besteht. Der basale Proteinansatz beträgt etwa 50 % des maximalen Ansatzes. Mit steigenden Energieaufnahmen wird der basale Proteinansatz mit einer zusätzlichen Menge von Protein und Fett im konstanten Verhältnis ergänzt.
    Notes: Summary With increasing intakes the body fat content increases and that of protein decreases. It is most often assumed that this is brought about because each increment in retention contains more fat and less protein. Experimental results, however, showed that this explanation is not true. In two experiments male broiler chickens were fed at levels between 60 and 100 % of recommended energy intake. Body composition at 1500 g showed, as expected, that with increasing intakes body fat content increased and protein content decreased. Both fat and protein retention per day were linearly related to total energy retention (ER). This means that each increment in retention has the same protein and fat content. At zero fat retention only protein was retained, about 50 % of maximal retention. At zero ER protein was retained and fat mobilized. Energy and N balance experiments confirmed the constant composition of each increment in retention. The results of both experiments show that total ER consisted of two components: a basic constant daily protein retention and a variable additional ER, mainly consisting of fat. The basic protein retention is about half of maximal retention. With increasing energy intakes the basic protein retention is combined with an additional amount of protein and fat in a constant ratio.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01617802
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  • 3
    Electronic Resource
    Electronic Resource
    The Maillard reaction in vivo (1991)
    Springer
    European journal of nutrition 30 (1991), S. 29-45 
    Details
    ISSN: 1436-6215
    Keywords: advanced glycosylation endproducts (AGE) ; ag(e)ing ; aminoguanidine ; ascorbate ; autoxidation ; biomarker ; browning reaction ; chemical modification of proteins ; diabetes ; glycation ; glycoxidation ; nonenzymatic glycosylation ; oxidation ; Maillard reaction ; Aminoguanidin ; Ascorbat ; Autooxidation ; Biomarker ; Bräunungsreaktion ; chemische Veränderung vonProteinen ; Diabetes ; Glycosylierung ; Glycoxidation ; nichtenzymatische ; Glycosylierung ; Oxidation ; Maillardreaktion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Die Maillard- oder Bräunungsreaktion genannten Umsetzungen zwischen reduzierenden Zuckern und Eiweiß führen zur chemischen Zerstörung der Aminosäuren und zum Verlust der Proteinqualität während der Lebensmittelbearbeitung und -lagerung. Der vorliegende Beitrag zeigt Befunde auf, daß die Maillardreaktion auch im Gewebe des Menschen bei der Alterung von Proteinen mit langer biologischer Halbwertszeit auftritt. Die Konzentrationen an den sogenannten Amadori-Produkten, die im Initialstadium der Maillardreaktion aus Glucose und den Proteinen der Augenlinse oder dem Kollagen der Haut entstehen, erwiesen sich als relativ konstant, auch mit zunehmendem Alter. Die Produkte der Glycosylierung und nachfolgenden Oxidation der Proteine, auch Glycoxidationsprodukte genannt, häufen sich dagegen im Alter an, und zwar bei Diabetikern in vermehrtem Maße. Zu diesen Produkten gehören die Aminosäurenderivate N-(carboxymethyl)-lysin (CML), N-(carboxymethyl)-hydroxylysin (CMhL) sowie das fluoreszierende Quervernetzungsprodukt Pentosidin. Während diese Glycoxidationsprodukte in den Körpergeweben nur in Spuren vorkommen, gibt es deutliche Hinweise auf die Anwesenheit weiterer Bräunungsprodukte, deren Charakterisierung jedoch noch aussteht. Es werden Möglichkeiten zur „Entgiftung“ der reaktiven Zwischenprodukte aus der Maillardreaktion sowie zum Abbau extrem gebräunter Proteine diskutiert sowie neuere Möglichkeiten zur therapeutischen Modulierung fortgeschrittener Stadien der Maillardreaktion aufgezeigt.
    Notes: Summary The Maillard or browning reaction between reducing sugars and protein contributes to the chemical deterioration and loss of nutritional value of proteins during food processing and storage. This article presents and discusses evidence that the Maillard reaction is also involved in the chemical aging of long-lived proteins in human tissues. While the concentration of the Amadori adduct of glucose to lens protein and skin collagen is relatively constant with age, products of sequential glycation and oxidation of protein, termed glycoxidation products, accumulate in these long-lived proteins with advancing age and at an accelerated rate in diabetes. Among these products are the chemically modified amino acids, Nɛ-(carboxymethyl)lysine (CML), Nɛ-(carboxymethyl)hydroxylysine (CMhL), and the fluorescent crosslink, pentosidine. While these glycoxidation products are present at only trace levels in tissue proteins, there is strong evidence for the presence of other browning products which remain to be characterized. Mechanisms for detoxifying reactive intermediates in the Maillard reaction and catabolism of extensively browned proteins are also discussed, along with recent approaches for therapeutic modulation of advanced stages of the Maillard reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01910730
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  • 4
    Electronic Resource
    Electronic Resource
    Nutrient intake and protein metabolism: responses to feeding (1997)
    Springer
    European journal of nutrition 36 (1997), S. 332-335 
    Details
    ISSN: 1436-6215
    Keywords: Nutrient intake ; protein metabolism ; protein synthesis ; growth ; energy expenditures ; Nährstoffaufnahme ; Proteinstoffwechsel ; Proteinsynthese ; Wachstum ; Energieaufwand
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Eine Zunahme von fettfreiem Gewebe tritt auf, wenn die Proteinsynthese größer ist als der Proteinabbau. Obwohl während des Wachstums von der Geburt bis zur Reife die absoluten Proteinsynthese- und -abbauraten ansteigen, nehmen dagegen die fraktionellen Raten ab. Bcide Prozesse reagieren auf die Nährstoffaufnahme. Es gibt aber deutliche Unterschiede zwischen den verschiedenen Geweben. Protein, Kohlenhydrate und Fett können den Proteinansatz bei unreifen Tieren und Kindern stimulieren. Die zugrundeliegenden Mechanismen und die Energieaufwendungen scheinen jedoch unterschiedlich zu sein.
    Notes: Summary Lean tissue growth occurs when the rate of protein synthesis exceeds the rate of protein breakdown. Althoughabsolute rates of protein synthesis and breakdown rise during growth from birth to maturityfractional rates fall. Both these processes are sensitive to nutrient intake but responses to feeding vary greatly amongst different tissues. Protein, carbohydrate and fat can all stimulate body protein accretion in immature animals and in children but the mechanisms by which they do so, and the energy expenditures involved, seem to be different.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01617817
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  • 5
    Electronic Resource
    Electronic Resource
    Convergence across industrialised countries (1890–1989): new results using time series methods (1999)
    Springer
    Empirical economics 24 (1999), S. 23-44 
    Details
    ISSN: 1435-8921
    Keywords: Key words: Cointegration ; convergence ; growth ; Kalman filter ; JEL classifications: C22 ; O47 ; O57
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract. Augmented Dickey Fuller (ADF) and Kalman filter convergence tests are applied to annual GDPs per head to 16 industrialised countries from 1890 to 1989. Results favour convergence towards the US with a structural break following the Second World War. Estimates suggest that steady-states were higher after the war and that speeds of convergence are different across countries. The Kalman filter method dismissed the no convergence hypothesis more often than its ADF counterpart. This could explain the apparent contradiction in earlier empirical work on similar data sets (cross-section methods tended to favour convergence while time series methods were unable to dismiss the no convergence hypothesis.)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001810050042
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  • 6
    Electronic Resource
    Electronic Resource
    Grapevine leaf gas exchange, plant growth, yield, fruit quality and carbohydrate reserves influenced by the grape leafhopper,Empoasca vitis (1993)
    Springer
    Entomologia experimentalis et applicata 69 (1993), S. 289-296 
    Details
    ISSN: 1570-7458
    Keywords: Vitis vinifera ; Empoasca vitis ; leafhopper ; photosynthesis ; transpiration ; stomatal conductance ; mesophyll conductance ; growth ; yield ; fruit quality ; starch ; carbohydrate reserves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The impact of the grape leafhopper,Empoasca vitis, on leaf gas exchange, plant growth, yield, fruit quality and carbohydrate reserves of the grapevines,Vitis vinifera L., was studied. Gas exchange was measured on the discolored (red) and the green parts of infested main leaves and on leaves from uninfested vines. Photosynthesis and mesophyll conductance were severely reduced on main leaves showing leafhopper feeding symptoms. The stomatal conductance of the red leaf section of infested main leaves was lower than on undamaged control leaves. Additionally, the red leaf section of infested main leaves showed lower transpiration rates when compared to the green parts of the same leaves and to undamaged control leaves. Gas exchange processes of lateral leaves were not affected by leafhopper feeding. Leafhopperload on main leaves was correlated to visual damage symptoms. At 71.8 leafhopper-days per leaf up to 40% of the main leaf area of the infested plants was discolored from the borders towards the center. Lateral leaves showed no feeding symptoms. Shoot diameter, pruning weight and carbohydrate reserves in the wood were not affected by leafhoppers. Lateral leaf area growth was significantly stimulated on plants infested by leafhoppers. No decrease in yield and fruit quality with leafhopper-loads up to 71.8 leafhopper-days per leaf were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382000
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  • 7
    Electronic Resource
    Electronic Resource
    Oviposition plant preference and offspring performance in the comma butterfly: correlations and conflicts (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 141-144 
    Details
    ISSN: 1570-7458
    Keywords: Polygonia c-album ; Nymphalidae ; host-plant selection ; growth ; size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194743
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of bean and wheat α-amylase inhibitors on α-amylase activity and growth of stored product insect pests (1995)
    Springer
    Entomologia experimentalis et applicata 75 (1995), S. 237-244 
    Details
    ISSN: 1570-7458
    Keywords: amylase inhibitor ; red kidney bean ; hard red winter wheat ; growth ; insects ; beetles ; plant resistance ; stored products ; protease inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Insect α-amylase inhibiting and/or growth inhibiting activities of proteinaceous inhibitors from red kidney bean (Phaseolus vulgaris) and hard red winter wheat (Triticum aestivum) were examined. The bean inhibitor was most effectivein vitro against α-amylases from the red flour beetle (Tribolium castaneum) and the confused flour beetle (T. confusum), followed by those from the rice weevil (Sitophilus oryzae) and yellow mealworm (Tenebrio molitor). The insect enzymes were from two- to 50-fold more susceptible than human salivary α-amylase. When the inhibitors were added at a 1% level to a wheat flour plus germ diet, the growth of red flour beetle larvae was slowed relative to that of the control group of larvae, with the bean inhibitor being more effective than the wheat inhibitor. Development of both the red flour beetle and flat grain beetle (Cryptolestes pusillus) was delayed by 1% bean inhibitor, but development of the sawtoothed grain beetle (Oryzaephilus surinamensis) and lesser grain borer (Rhyzopertha dominica) was not affected by either the bean or wheat inhibitor at the 1% level. Rice weevil adults fed a diet containing 1% bean or wheat inhibitor exhibited more mortality than weevils fed the control diet. When the wheat amylase inhibitor was combined with a cysteine protease inhibitor, E-64, and fed to red flour beetle larvae, a reduction in the growth rate and an increase in the time required for adult eclosion occurred relative to larvae fed either of the inhibitors separately. The bean inhibitor was just as effective alone as when it was combined with the protease inhibitor. These results demonstrate that plant inhibitors of insect digestive enzymes act as growth inhibitors of insects and possibly as plant defense proteins, and open the way to the use of the genes of these inhibitors for genetically improving the resistance of cereals to storage pests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382258
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  • 9
    Electronic Resource
    Electronic Resource
    Do Maculinea rebeli caterpillars provide vestigial mutualistic benefits to ants when living as social parasites inside Myrmica ant nests? (2000)
    Springer
    Entomologia experimentalis et applicata 95 (2000), S. 97-103 
    Details
    ISSN: 1570-7458
    Keywords: butterfly ; Formicidae ; food ; growth ; mutualism ; myrmecophily ; parasitism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Caterpillars of the lycaenid butterfly Maculinea rebeli Hirschke (Lepidoptera: Lycaenidae) live for 11–23 months as social parasites in Myrmica (Hymenoptera: Formicidae) red ant nests, a trait that is believed to have evolved from mutualistic myrmecophilous ancestry. Although Maculinea rebeli caterpillars harm Myrmica larvae, they simultaneously produce copious secretions which the adult worker ants imbibe, perhaps representing a vestige of the ancestral mutualism. We report the results of laboratory experiments designed to test alternative hypotheses: (i) Maculinea rebeli caterpillars provide a beneficial source of sugar in return for being tended by Myrmicaworkers; (ii) Maculinea rebeli harms its host by stressing the workers by competing for available sugar. Comparisons were made of Myrmica worker fitness after 90–450 days under all possible combinations of three experimental treatments: ± M. rebeli caterpillars, ± sucrose and ± ant brood. Caterpillars always reduced the survival of both ant workers and their larvae, even when sugar was not provided, suggesting that M. rebeli is wholly parasitic on all stages in its host colony. The results also confirmed the importance of sucrose in the diet of Myrmica, and showed that M. rebeli caterpillars which eat ant brood to supplement their normal trophallactic feeding by workers develop more quickly - but have the same survival and pupal weights – as caterpillars that are fed solely by worker ants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003950318095
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of temperature, multiple allelochemicals and larval age on the performance of a specialist caterpillar (1996)
    Springer
    Entomologia experimentalis et applicata 79 (1996), S. 335-344 
    Details
    ISSN: 1570-7458
    Keywords: alkaloid ; developmental time ; early instars ; growth ; Manduca sexta ; molting duration ; phenolics ; plant-herbivore interactions ; thermal regime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To understand the mechanisms underlying plant-insect herbivore interactions, it is necessary to examine the simultaneous effects of temperature, food quality and larval age. We examined the simultaneous effects of three allelochemicals (tomatine, rutin and chlorogenic acid) on the performance of first and second instar Manduca sexta larvae under two representative thermal regimes 21 : 10°C and 26 : 15°C for spring and summer, respectively. Thermal regime and allelochemicals interacted to influence the time from egg hatch to ecdysis to the third instar. On average, it took about half as much time to reach the third instar at 26 : 15°C as it did at 21 : 10°C. Separately, tomatine and rutin had a negative effect on developmental time from egg hatch to the third instar, but their simutaneous effects were not additive. Chlorogenic acid significantly reduced the negative effect of tomatine. The magnitude of the allelochemical effect was larger at the cooler thermal regime compared to the warmer regime. For instance, chlorogenic acid by itself had no effect at the 26 : 15°C regime, but at the 21 : 10°C regime it significantly shortened total developmental time. The effect of chlorogenic acid on stadium duration was distinctly different for the two instars. Chlorogenic acid shortened stadium duration of first instar larvae. However, depending on thermal regime and the presence of tomatine, chlorogenic acid had a negative, positive or neutral effect on stadium duration of second instar larvae. Molting duration of second instar larvae was shortened by a half day at the warmer thermal regime but was not affected by the allelochemicals. Final larval weight was influenced by rutin and chlorogenic acid. Caterpillars fed diets containing 20 μmoles of rutin were on average 10% lighter than those fed plain diet, whereas those fed diets containing 20 μmoles of chlorogenic adic were on average 7% heavier. However, the effect of chlorogenic acid depended on thermal regime. Overall, our results indicated that: 1) temperature and food quality can interact to influence insect performance and 2) these effects are influenced by larval age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186292
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  • 11
    Electronic Resource
    Electronic Resource
    Effects of the ecdysteroid agonists RH 5849 an RH 5992, alone and in combination with a juvenile hormone analogue, pyriproxyfen, on larvae ofSpodoptera exigua (1994)
    Springer
    Entomologia experimentalis et applicata 72 (1994), S. 115-123 
    Details
    ISSN: 1570-7458
    Keywords: ecdysteroid agonists ; juvenile hormone analogue ; Spodoptera exigua ; growth ; moulting ; metamorphosis ; imaginal discs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Biological activity assays with RH 5849 and RH 5992 indicated that both compounds affected growth and development of last-instar larvae ofSpodoptera exigua (Hübner) (Lepidoptera: Noctuidae) in a dose-dependent manner. Within the first 24 h after treatment by continuously offering leaves dipped in a water solution of ≥50 mg/l RH 5849 and ≥0.5 mg/l RH 5992, symptoms of a prematurely induced larval moult and head capsule apolysis were visible. Intoxicated larvae died shortly afterwards, showing signs of unsuccessful ecdysis. LC50-values of RH 5849 and RH 5992 for fifth-instarS. exigua larvae were 110 and 2.5 mg/l, respectively. Pyriproxyfen alone affected the larval stage and disturbed normal metamorphosis. One supernumerary larval instar occurred occasionally. LC50-value for pyriproxyfen was 1.7 mg/l. Larvae simultaneously treated with RH 5849 or RH 5992 and pyriproxyfen, continued to grow until they attained a size and weight about 2–3 times that of the controls. This growth was accompanied by at least one and sometimes two supernumerary moults. Concerning thein vivo imaginal wing disc growth and development, only in larvae treated with 10 and 50 mg/l RH 5849 or 0.5 mg/l RH 5992, tracheole migration was observed earlier than in the controls. When applying 300 mg/l RH 5849 or 3–7 mg/l RH 5992, the discs remained small and no signs of tracheole migration were observed. In larvae simultaneously treated with RH 5849 or RH 5992 and pyriproxyfen, tracheole migration was not prematurely induced and a pupal cuticle was produced in the discs of larvae, undergoing a supernumerary moult. No clear signs of evagination were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02383546
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  • 12
    Electronic Resource
    Electronic Resource
    Effects of natural and synthetic neuroactive substances on the growth and feeding of cabbage looper, Trichoplusia ni (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 443-451 
    Details
    ISSN: 1570-7458
    Keywords: beta-carboline alkaloid ; Trichoplusia ni ; harmane ; harmaline ; amitriptyline ; imipramine ; monoamine oxidase inhibitor ; tricyclics ; growth ; feeding behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this study we investigated the effects of two naturally occurring beta-carboline alkaloids and two synthetic tricyclic antidepressants on the growth and food consumption of fifth instar larvae of the cabbage looper, Trichoplusia ni Hübner (Lepidoptera: Noctuidae). In artificial diets at high concentrations (3,000 ppm), harmane, amitriptyline, and imipramine reduce growth and feeding; harmane reduced feeding consistently at a lower concentration (200 ppm). In animals other than insects, beta-carboline alkaloids inhibit monoamine oxidase (MAO) activity and thus affect rates of disposition of serotonin and other monoamine neurotransmitters. Because brain serotonin levels are associated with variation in rates of carbohydrate and protein intake in insects, the effects of beta-carboline alkaloid ingestion on dietary self-selection behavior were examined. Choosing between diets lacking carbohydrate but containing protein and diets lacking protein but containing carbohydrate, larvae consumed a greater proportion of diet containing protein but lacking carbohydrate in the presence of harmane than in its absence. These results are consistent with beta-carboline alkaloid-mediated persistence of serotonin in the brain due to MAO inhibition. Alternatively, these results could reflect alkaloid-mediated peripheral inhibition of sucrose taste receptors influencing ingestive behaviors. That beta-carboline alkaloid ingestion is associated with changes in feeding behavior is consistent with a possible defensive role for these compounds in plant foliage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343467
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  • 13
    Electronic Resource
    Electronic Resource
    The folliculostatins of two dipteran insect species, their relation to matrix proteins and prospects for practical applications (1995)
    Springer
    Entomologia experimentalis et applicata 77 (1995), S. 1-9 
    Details
    ISSN: 1570-7458
    Keywords: insect endocrinology ; ecdysone ; juvenile hormone ; reproduction ; growth ; inhibin ; oostatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The first insect folliculostatic peptide was isolated from vitellogenic ovaries of the mosquitoAedes aegypti. This decapeptide directly inhibits trypsin biosynthesis in the gut, and indirectly ovarian development. The factor was named Trypsin Modulating Oostatic Factor or TMOF by its discoverers. From the fleshfly Neobellieria bullata 2 folliculostatins have been isolated, the hexapeptide Neb-TMOF and the 19-mer Neb-colloostatin. The available data suggest that at least 2 of the 3 folliculostatins originate from matrix (like) proteins present in the ovary, a hitherto unknown source of hormones. Furthermore, one of the folliculostatins (Neb-TMOF) is a potent inhibitor of ecdysone biosynthesis by larval ring glands of fleshflies. The discovery of the dipteran folliculostatins, which do not show any resemblance to inhibins of vertebrates, may significantly contribute to a better understanding of the hormonal control of growth in insects and perhaps, in other animals as well. None of the 3 folliculostatins is blocked at its N- or C-terminus. This, in combination with the pleiotropy of their effects and the narrow species specificity make such peptides prime candidates for, testing their potential in insect pest control by means of molecular biological methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02383011
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  • 14
    Electronic Resource
    Electronic Resource
    Influence of larval dietary supply on the food consumption, food utilization efficiency, growth and development of the lacewingChrysoperla carnea (1993)
    Springer
    Entomologia experimentalis et applicata 67 (1993), S. 1-7 
    Details
    ISSN: 1570-7458
    Keywords: Chrysoperla carnea ; food consumption ; growth ; development ; efficiency of food utilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Larvae of the common green lacewing,Chrysoperla carnea (Stephens)(Neuroptera: Chrysopidae), were fed either an optimal or a suboptimal number of eggs of the mothAnagasta kuehniella (Zeller) in the first and/or second larval instar, or in all three larval instars. Parameters for the duration, growth, and the efficiency of conversion of ingested food to body substance (ECI) of each instar were established for seven different dietary regimes. Larvae that had a suboptimal food supply in the first instar had a significantly longer developmental time, gained significantly less weight, and had a slightly lower ECI in that instar larvae. Suboptimally-fed second less, but remained only slightly longer in that instar and had a similar ECI to optimally-fed second instar larvae. The developmental time of suboptimally-fed third instar larvae was similar to that of optimally-fed larvae of that stage. Whereas the growth of the former was significantly less than that of larvae optimally fed in that instar, the ECI of the former was significantly higher. Despite the relatively smaller size of larvae fed suboptimally in the first and/or second instar, when such larvae were subsequently supplied with an overabundance of prey eggs, they consumed approximately the same number of eggs during the remainder of their larval life as did larvae whose food supply had not been restricted previously. When larvae were allowed to consume different numbers of eggs in their third instar, their gain in weight and therefore the weights attained by the resulting adults (based on the weights of 3-day-old cocoons) had a highly significant positive correlation with the number of eggs consumed in this instar.
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    URL: http://dx.doi.org/10.1007/BF02382710
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    Gravimetricvs. respirometric determination of metabolic efficiency in caterpillars ofPieris brassicae (1993)
    Springer
    Entomologia experimentalis et applicata 67 (1993), S. 135-142 
    Details
    ISSN: 1570-7458
    Keywords: nutrition ; utilization ; efficiency ; growth ; metabolism ; energy ; respirometry ; Pieris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Conventional gravimetry and a combination of gravimetry and respirometry were compared for their precision in measuring respiration and metabolic efficiency of growth of final stadiumPieris brassicae L. (Pieridae, Lepidoptera) caterpillars. This was done both for caterpillars feeding on an artificial diet and for caterpillars feeding on excised leaf material of a host plant,Brassica oleracea L. Gravimetry produced significantly greater variation in the total amount of matter respired and the metabolic efficiency than indirect calorimetry for caterpillars feeding on plant material, while the two methods gave similar results for the caterpillars reared on a meridic artificial diet. Respirometry (indirect calorimetry) revealed that caterpillars feeding on the artificial diet were growing with a higher metabolic efficiency than caterpillars feeding on the host plant. This difference was not revealed by conventional gravimetry. It is argued that metabolic efficiencies as derived from gravimetric budget calculations are subject to a number of random errors that distort precise determination of metabolic efficiencies in studies involving plant food.
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    URL: http://dx.doi.org/10.1007/BF02386518
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    Azadirachtin inhibits secretion of trypsin in midgut of Manduca sexta caterpillars: reduced growth due to impaired protein digestion (1992)
    Springer
    Entomologia experimentalis et applicata 63 (1992), S. 47-54 
    Details
    ISSN: 1570-7458
    Keywords: Azadirachtin ; Manduca sexta ; growth ; feeding efficiency ; nitrogen utilisation ; proteinase ; trypsin ; allelochemicals ; antifeedant ; herbivory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When given by injection to tobacco hornworm caterpillars, Manduca sexta, the allelochemical azadirachtin inhibits growth without reducing food intake. The growth reducing effect of azadirachtin is therefore in this case independent of the compound's well-known antifeedant effect. The cause of this reduced rate of growth is an increase in the costs associated with growth. These increased costs are largely a consequence of a decrease in the efficiency of utilisation of dietary nitrogen. This is associated with a drastic reduction in the activity of midgut trypsin. Azadirachtin has no effect on the activity of trypsin in vitro. Thus azadirachtin directly or indirectly inhibits the production of trypsin by the enzyme-secreting cells of the midgut wall; it is suggested that this is the cause of the increased costs and reduced rate of growth. The interesting parallel between this plant defence strategy and that of direct inhibition of herbivore proteinases by allelochemical proteinase inhibitors is discussed.
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    URL: http://dx.doi.org/10.1007/BF00350345
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  • 17
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    Oxidation of bridging groups by carboxylate coordinated ligands in palladium clusters (1992)
    Springer
    Journal of cluster science 3 (1992), S. 411-421 
    Details
    ISSN: 1572-8862
    Keywords: Palladium ; carbene ; oxidation ; phosphonate ; carboxylate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Thermolysis of tetranuclear palladium clusters Pd4(μ-Q)4 Pd4(μ-Q)4(μ-O2CR)4 (Q=CPh2 or CO;R=Me, CMe3, Ph, CH2Cl or CF3) has been found to involve innersphere oxidation of carbene or carbonyl ligands during which an oxygen atom transfer occurs from the carboxylate group to the carbene or carbonyl ligand. The thermolysis of the carbonyl clusters gives rise to the products of CO2 insertion into the C–H bond of benzene or toluene used as solvents forming benzoic acid from benzene and a mixture of phenylacetic and toluic acids from toluene. The reaction of [Pd(OAc)2(PPh3)]2 with HCO2H includes the transfer of an O atom from formate ligand to the P atom and cleavage of the P-Ph bond accompanied by transfer of the Ph group from PPh3 ligand to the palladium atom. The structure of the complex formed, [Pd(μ-O2PPh2)(C6H5)(PPh3)]2, has been resolved by X-ray analysis.
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    URL: http://dx.doi.org/10.1007/BF00702748
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    Chemiluminescence in evaluating the thermal oxidative stability of acrylonitrile-butadiene-styrene (ABS) copolymers. II. ABS/polycarbonate (PC) blends (1993)
    Springer
    Journal of polymers and the environment 1 (1993), S. 275-279 
    Details
    ISSN: 1572-8900
    Keywords: Chemiluminescence ; oxidation ; stability ; acrylonitrile-butadiene-styrene (ABS) ; ABS/polycarbonate blend
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The thermal oxidative stability of various ABS/PC compounds was studied by means of the chemiluminescence technique. Similarly to pure ABS, Irganox 1076 and Irganox MD 1024 perform as moderate antioxidants in ABS/PC and (ABS/PC + lubricant) blends. Neither Tinuvin 144, Irgaphos 168, nor their mixture affects the durability of the ABS/PC blend. At the same time, (Irgaphos 168 + Tinuvin 144) in combination with Irganoxes was found to provide a noticeable enhancement in durability to the (ABS/PC + lubricant) system. Titanium dioxide pigments by themselves have only a slight influence on the oxidative stability of the ABS/PC blend. Durability of the (ABS/PC + pigment) and (ABS/PC + lubricant) systems was found to be the same and the overall protective effect of Irganox 1076 was similar in both the (ABS/PC + lubricant) and the (ABS/PC + lubricant + pigment) systems. Certain modifiers significantly improve the durability of the ABS/PC compounds, although their function may differ in the systems with and without pigments.
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    URL: http://dx.doi.org/10.1007/BF01458294
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    Chemiluminescence in evaluating the thermal oxidative stability of acrylonitrile-butadiene-styrene (ABS) copolymers. 1. Influence of stabilizers and lubricants (1993)
    Springer
    Journal of polymers and the environment 1 (1993), S. 107-110 
    Details
    ISSN: 1572-8900
    Keywords: Chemiluminescence ; oxidation ; stability ; acrylonitrile-butadiene-styrene (ABS)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The influence of lubricants, UV stabilizers, antioxidants, and metal deactivators on the resistance of ABS to thermal oxidation was studied by means of the chemiluminescence technique. Neither of the additives seems to affect significantly the induction period of oxidation. At the same time, the influence of various additives on the oxidation rate constant is remarkably different: the introduction of lubricants and UV stabilizers increases its value, while antioxidants and metal deactivators have the opposite effect. For the particular systems studied durability is decreased in samples containing the lubricant and UV stabilizers and increased in samples stabilized with the antioxidant and metal deactivator.
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    URL: http://dx.doi.org/10.1007/BF01418203
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    Carbon monoxide electrooxidation on porous Pt–Ru electrodes in sulphuric acid (1997)
    Springer
    Journal of applied electrochemistry 27 (1997), S. 1275-1282 
    Details
    ISSN: 1572-8838
    Keywords: Carbon monoxide ; Pt-Ru/C catalyst ; Tafel slopes ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract CO electrooxidation on a Pt–Ru/C catalyst was investigated in sulphuric acid electrolyte. The physico-chemical properties of the Pt–Ru/C catalyst were studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The influence of temperature, CO partial pressure and proton concentration on the electrochemical oxidation rate was investigated by steady-state galvanostatic polarization measurements. The apparent activation energy decreased from 70 to 30kJmol−1 as the overpotential increased from 0.5 to 0.9V vs NHE. The reaction order with respect to carbon monoxide increased, passing from 0.4 to 1, with the increase of the overpotential from 0.5 to 0.7V vs NHE; a reaction order close to −1 with respect to the protonic concentration was observed, irrespective of the potential. Tafel slopes of about 136mVdec−1 were determined for oxidation of CO and CO/N2 mixtures.
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    URL: http://dx.doi.org/10.1023/A:1018492122263
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    Characterization and stability of doped SnO2 anodes (1998)
    Springer
    Journal of applied electrochemistry 28 (1998), S. 607-612 
    Details
    ISSN: 1572-8838
    Keywords: SnO2 anodes ; doping ; high overvoltage anodes ; surface analysis ; oxidation ; water treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Doped tin dioxide electrodes have been prepared by a standard spray pyrolysis technique. The electrochemical behaviour of these electrodes has been investigated by cyclic voltammetry in sulphuric acid using the Fe2+/Fe3+ redox couple system as test reaction. Oxygen evolution has been used to study the stability of doped SnO2 electrodes. The SnO2 electrodes doped with antimony and platinum exhibit the highest stability. XPS analysis shows that the oxidation state of Sn, Sb and Pt are +4, +3 and +2, respectively, the probable species being SnO2, Sb2O3 and PtO.
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    URL: http://dx.doi.org/10.1023/A:1003250118996
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    Phosphazene-bound Rose Bengal: A novel photosensitizer for singlet oxygen generation (1991)
    Springer
    Journal of inorganic and organometallic polymers and materials 1 (1991), S. 389-395 
    Details
    ISSN: 1572-8870
    Keywords: Poly(organophosphazenes) ; cyclophosphazenes ; Rose Bengal ; photosensitization ; singlet oxygen ; oxidation ; heterogeneous phase photosensitizer ; 1,3-diphenyl-isobenzofuran
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In this paper we report the synthesis and the characterization of cyclo- and polyphosphazenes supporting Rose Bengal. These substrates are suitable for the photosensitized generation of singlet oxygen, both in homogeneous and in heterogeneous phase. The efficiency of1O2 production has been measured in homogeneous solution using, as photosensitizer, the cyclophosphazene-bound Rose Bengal and considering, as testing reaction, the oxidation of 1,3-diphenylisobenzofuran; it was found comparable to that of free Rose Bengal in the same experimental conditions.
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    URL: http://dx.doi.org/10.1007/BF00702501
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    Biomass conversion: attempted electrooxidation of lignin for vanillin production (2000)
    Springer
    Journal of applied electrochemistry 30 (2000), S. 727-731 
    Details
    ISSN: 1572-8838
    Keywords: electrosynthesis ; oxidation ; lignin ; vanillin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Electrochemical oxidative degradation of Kraft lignin was investigated in batch and flow cells on Pt, Au, Ni, Cu, DSA–O2 and PbO2 anodes. Production of vanillin was evaluated by means of formal kinetic analyses. Conversion and chemical yields were found to be dependent mainly on the applied current density, that is on the partial pressure of oxygen at the interface, while the nature of the electrode influenced the reaction rates.
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    URL: http://dx.doi.org/10.1023/A:1004003613883
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    Synthesis and crystal structure of 1-acetyl-3-bromo-3-phenylazetidine and 1-phenyl-2-(N-acetyl-N-formyl)-aminoethanone (1998)
    Springer
    Journal of chemical crystallography 28 (1998), S. 119-123 
    Details
    ISSN: 1572-8854
    Keywords: Azetidine ; azetine ; ring opening ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract 1-Acetyl-3-bromo-3-phenylazetidine (1), C11H12BrNO, has been synthesized and characterized by spectroscopic methods and single crystal X-ray analysis. It crystallizes in the space group P2 1/c with a = 8.633(1), b = 7.461(1), c = 17.204(1) Å, β = 98.403(7)°, V = 1096.2(2) Å3, Z = 4, D calc = 1.540 g cm−3. The azetidine ring is nearly planar since the four atoms are within ±0.039(5) Å of the mean square plane calculated for the heterocycle. The attempt to obtain a highly strained 2-azetine derivative from the above compound gave, surprisingly, 1-phenyl-2-(N-acetyl-N-formyl)-aminoethanone (2), C11H11NO3. This compound has been also characterized by spectroscopic methods and single crystal X-ray analysis. It crystallizes in the space group P212121, with a = 5.4719(3), b = 8.3205(6), c = 23.298(3) Å, V = 1060.7(2) Å3, Z = 4, D calc = 1.286 g cm−3. The aminoethanone residue is in a near planar conformation where the torsion angles are 7(2)° for N–C–C–=O and −173(2)° for N–C–C–C(Ph).
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    URL: http://dx.doi.org/10.1023/A:1022489729966
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    Oxidation of 3-methylindole catalyzed by cobalt(II)phthalocyanines covalently bound to polyorganosiloxane (1991)
    Springer
    Journal of inorganic and organometallic polymers and materials 1 (1991), S. 211-221 
    Details
    ISSN: 1572-8870
    Keywords: Polyorganosiloxane ; cobalt(II)phthalocyanine ; polymeric catalyst ; oxidation ; 3-methylindole ; polymer conformation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two kinds of cobalt(II)phthalocyanines covalently bound to polyorganosiloxane (POS) were prepared to be applied as catalysts for the oxidation of 3-methylindole in organic solvents. The catalytic activity of the POS whose carboxyl residues were methyl-esterified was high compared with that of the POS which has carboxyl residues. The former polymeric atalyst exhibited higher catalytic activity than monomolecular phthalocyanine, indicating an appearance of effects of polymer chains. The factors which influence the catalytic oxidation, e.g., polymer conformations, basicity of solvents, and equilibrium involving phthalocyanine monomer and the dimer, are discussed. It has become apparent that polymer conformation influences catalytic activity and that the catalytic activity of the POS, whose main chains are mobile, is high.
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    URL: http://dx.doi.org/10.1007/BF00701320
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    Chemiluminescence in evaluating thermal oxidative stability of acrylonitrile-butadiene-styrene (ABS) copolymers. III. Emulsion-grade products (1995)
    Springer
    Journal of polymers and the environment 3 (1995), S. 199-203 
    Details
    ISSN: 1572-8900
    Keywords: Chemiluminescence ; oxidation ; stability ; acrylonitrile-butadiene-styrene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The thermal oxidative stability of various formulations based on emulsion-grade ABS was studied by the chemiluminescence technique. Emulsion products were found to be essentially less stable than ionic mass polymerization resins. Among the antioxidants studied, Santonox R is clearly more efficient than Irganox 1076 and Irganox 3114, and its superiority is reflected primarily in improved induction period values. The introduction of Tinuvin 770 and Tinuvin 328 UV stabilizers into emulsion resins does not change the durability of the products. In mixtures where both Irganox 1076 and UV stabilizers are present, a certain antagonistic effect was noted at high UV stabilizer concentrations.
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    URL: http://dx.doi.org/10.1007/BF02068674
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    Effect of ionic interactions on the oxidation of Fe(II) with H2O2 in aqueous solutions (1991)
    Springer
    Journal of solution chemistry 20 (1991), S. 1079-1092 
    Details
    ISSN: 1572-8927
    Keywords: Fe(II) ; oxidation ; H2O2 ; ionic strength ; NaCl ; NaClO4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidation of Fe(II) with H2O2 has been measured in NaCl and NaClO4 solutions as a function of pH, temperature T (K) and ionic strength (M, mol-L−1). The rate constants, k (M−1-sec−1), d[Fe(II)]/DT=-k[Fe(II)][2O2] at pH=6.5 have been fitted to equations of the form log k = log k0+ AI 1/2+BI+CI 1/2/T Where log k0=15.53-3425/T in water; A=−2.3, −1.35; B=0.334, 0.180; and C=391, 235, respectively, for NaCl (σ=0.09) and NaClO4 (σ =0.08). Measurements made in NaCl solutions with added anions yield rates in the order B(OH) 4 − 〉HCO 3 − 〉ClO 4 − 〉Cl−〉NO 3 − 〉SO 4 2− and are attributed to the relative strength of the interactions of Fe2+ or FeOH+ with these anions. The FeB(OH) 4 + species is more reactive while the FeCO 3 0 , FeCl+, FeNO 3 + and FeSO 4 0 species are less reactive than the FeOH+ ion pair. The general trend is similar to our earlier studies of the oxidation of Fe(II) with O2 except for B(OH) 4 − . The effect of pH on the logk was found to be a quadratic function of the concentration of H+ or OH− from pH=4 to 8. These results have been attributed to the different rate constants for Fe2+ (k0) and FeOH+ (k1) which are related to the measured k by, k=k0αFe + k1αFeOH, where αi is the molar fraction of species i. The rates increase due to the greater reactivity of FeOH+ compared to Fe2+. k0 is independent of composition and ionic strength but k1 is a function of ionic strength and composition due to the interactions of FeOH+ with various anions.
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    Preparation and characterization of bimodal porous carbons derived from a styrene-divinylbenzene copolymer (1997)
    Springer
    Adsorption 3 (1997), S. 67-79 
    Details
    ISSN: 1572-8757
    Keywords: porous carbons ; activation ; oxidation ; surface oxygen groups ; LTPD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A styrene/divinylbenzene copolymer has been used as precursor for making porous carbons with bimodal pore size distributions (i.e., with both microporosity and mesoporosity). Pretreatment of the as-received copolymer by mild oxidation in air, significantly increased the carbon yield after carbonization. Reactivity studies of the polymer-based chars to CO2 clearly show the influences of some important factors such as carbonization temperature, heating rate, soak time on char reactivities. Bimodal porous carbons were prepared by carbonization of the preoxidized styrene/divinylbenzene copolymer in N2, followed by activation in CO2 at different temperatures to different levels of burnoff. The pore structures of the porous carbons produced have been characterized by various techniques such as gas adsorption and mercury porosimetry. The surfaces of the porous carbons produced, and a commercial carbon adsorbent, have been modified with HNO3 and H2O2 treatment at various conditions. Characterization of the surface oxygen functionality, both quantitatively and qualitatively, has been achieved using techniques such as Linear Temperature Programed Desorption (LTPD) and selective neutralization of bases.
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    The Influence of Catalyst Composition on the Oxidation Process of Carbonado Type Synthesized Polycrystalline Diamonds (1997)
    Springer
    Advanced performance materials 4 (1997), S. 297-304 
    Details
    ISSN: 1572-8765
    Keywords: carbonado ; diamond ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The oxidation of carbonado type synthesized polycrystalline diamonds produced from graphite together with catalytic Ni-Mo alloy doped with TiB2 and BNcub was investigated. It was found that the addition of these boron compounds increases the oxidation resistance of the carbonado type synthesized polycrystalline diamonds. The oxidation mechanism acting on the carbonado type synthesized polycrystalline diamonds and the role of boron compounds in increasing the resistance to the oxygen reaction are discussed.
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    URL: http://dx.doi.org/10.1023/A:1008677105534
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    Mechanism for the formation of carbon dioxide in the catalytic oxidation of carbon monoxide and methane on silica (1992)
    Springer
    Catalysis letters 13 (1992), S. 283-288 
    Details
    ISSN: 1572-879X
    Keywords: Silica ; oxidation ; methane ; carbon monoxide ; carbon dioxide ; labelled reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidation of carbon monoxide to carbon dioxide is shown to be catalyzed at 850 K or above over almost all lattice oxygen atoms on the surface of silica prepared by the sol-gel method from ethyl orthosilicate under conditions which yield high selectivity to carbon dioxide in the oxidation of methane.
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    URL: http://dx.doi.org/10.1007/BF00771001
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    The partial oxidation of some cyclohexenes and branched chain olefins over a silver catalyst (1992)
    Springer
    Catalysis letters 16 (1992), S. 149-158 
    Details
    ISSN: 1572-879X
    Keywords: Silver ; oxidation ; cyclohexenes ; branched chain olefins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidation of some cyclic and branched chain olefins over a silver catalyst effective for the conversion of ethylene to ethylene oxide has been investigated in a steady state flow system. The reaction of cyclohexene produces benzene and that of both 1-methylcyclohexene and 4-methylcyclohexene yields toluene. The selectivity to aromatics exceeds 20% for fractional conversions below 0.2, but it can be improved to almost 50% by inclusion of an optimum quantity of dichloroethane in the feed. Styrene is oxidised more slowly than the cyclohexenes and only carbon dioxide and water are produced. The oxidation of 3,3-dimethyl-1-butene and 3-methyl-1-butene occurs much faster than that of the cyclic molecules and some of the corresponding epoxides are produced. The selectivity with the dimethyl-butene is 9–13% for conversions to 0.2. The methylbutene requires a higher temperature for reaction and the epoxide yield is lower. Factors influencing reactivity and product distribution are discussed.
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    Factors affecting bioleaching kinetics of sulfide ores using acidophilic micro-organisms (1999)
    Springer
    BioMetals 12 (1999), S. 1-10 
    Details
    ISSN: 1572-8773
    Keywords: acidophilic ; strain ; oxidation ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Recovery of metal values from sulfide ores by use of acidophilic microorganisms is gaining importance. A number of commercial/pilot plants are setup to find out the techno-economic feasibility of the overall process. The main drawback in the process is the slow kinetics of dissolution of metal values from the sulfide ores. To make the technology e attractive the kinetics should be improved considerably. There are various factors which determine the overall kinetics such as bacterial activity and concentration, iron and sulfur oxidation, oxygen consumption, reactor design and nature of ore. A brief review has been made dealing with the above parameters
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    URL: http://dx.doi.org/10.1023/A:1009228210654
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    The molecular structures and reactivity of V2O5/TiO2/SiO2 catalysts (1992)
    Springer
    Catalysis letters 13 (1992), S. 9-19 
    Details
    ISSN: 1572-879X
    Keywords: Vanadia ; titania ; silica ; Raman ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A series of V2O5/TiO2/SiO2 catalysts were structurally investigated byin situ Raman spectroscopy and chemically probed by methanol oxidation in order to determine the molecular structure-reactivity relationships of the V2O5/TiO2/SiO2 catalysts. Only surface TiO x species are present on the 3% TiO2/SiO2 catalysts, and the surface TiO x species as well as bulk TiO2 (anatase) particles coexist on the 40% TiO2/SiO2 catalyst. The deposition of 1–3% vanadium oxide onto 3% TiO2/SiO2 and 4% vanadium oxide onto 40% TiO2/SiO2 forms only a surface vanadium oxide phase.In situ Raman studies reveal that the surface vanadium oxide species preferentially exist on the titania sites of the TiO2/SiO2 system. The interaction between the surface vanadia and the surface titania overlayer on SiO2 increases the methanol oxidation reactivity by two orders of magnitude relative to V2O5/SiO2. In the presence of bulk TiO2 (anatase) particles on the SiO7 support, the reactivity of the surface vanadia further increases by an order magnitude relative to the catalysts containing only surface titania, and is close to that of surface vanadia on bulk TiO2. This suggests that the surface VO x -TiO2 (bulk) interactions results in a more active site than the surface VO x -TiO x -SiO2 interactions. In addition, the V2O5/TiO2/SiO2 catalysts exhibit high selectivity towards HCHO because redox sites are predominant on the surface of these catalysts with essentially no acid site present.
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    URL: http://dx.doi.org/10.1007/BF00770942
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    High yield synthesis of propanal from methane and air (1992)
    Springer
    Catalysis letters 13 (1992), S. 341-347 
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    ISSN: 1572-879X
    Keywords: Methane ; oxidation ; oxidative coupling ; hydroformylation ; propanal ; catalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract High yield synthesis of propanal from methane and air can be obtained in a single pass at atmospheric pressure. Three catalytic processes are combined to give 13% yield of propanal based on total methane input. Ethene is made from the oxidative coupling reaction and carbon monoxide and hydrogen is generated from partial oxygenation of methane. These gases are combined and passed to a hydroformylation catalyst to give liquid propanal. The unreacted methane is inert in the hydroformylation stage, while oxygen deactivates the catalyst readily. The results imply that propanal can be obtained, in good yield, from methane and air provided that total oxygen conversion is achieved. The yield of propanal from the three combined processes can be substantially higher than that of ethene from the oxidative coupling reaction. Thus, higher yields of a condensible and oxygenated product are obtained.
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    Selective oxidation of secondary amines over titanium silicalite molecular sieves, TS-1 and TS-2 (1996)
    Springer
    Catalysis letters 37 (1996), S. 213-216 
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    ISSN: 1572-879X
    Keywords: titanium silicalites ; oxidation ; amines ; hydrogen peroxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Titanium silicalite molecular sieves, TS-1 and TS-2 having MFI and MEL structures, respectively, catalyze the oxidation of secondary amines to the corresponding hydroxylamines using hydrogen peroxide as the oxidant. Higher concentrations of H2O2 lead to further oxidation of hydroxylamine to nitrone. Diffuse reflectance spectroscopy shows the formation of a titanium peroxo complex upon addition of hydrogen peroxide to the TS-1 catalyst. The titanium peroxo complex oxidizes the substrate and reforms to a titanyl group.
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    Transient experiments on the selective oxidation of methane to formaldehyde over V2O5/SiO2 studied in the temporal-analysis-of-products reactor (1993)
    Springer
    Catalysis letters 21 (1993), S. 209-214 
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    ISSN: 1572-879X
    Keywords: Methane ; formaldehyde ; oxidation ; vanadium oxide ; silica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Methane oxidation to formaldehyde was studied over a vanadium oxide catalyst supported on silica at 630 °C using the technique known as temporal analysis of products with sequential pulsing of methane and oxygen. This work shows that methane interacts very weakly and oxygen very strongly with the catalyst surface and it is concluded that the initial activation of methane involves an adsorbed oxygen species. Methyl radicals formed in the first step subsequently extract lattice oxygen to yield formaldehyde.
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    Novel iron meso-nitrooctaethylporphine complexes for the catalytic reaction of alkanes with molecular oxygen (1994)
    Springer
    Catalysis letters 24 (1994), S. 79-83 
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    ISSN: 1572-879X
    Keywords: Metallonitroporphines ; oxidation ; isobutane ; propane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Introducing nitro groups into themeso-positions of a metalloporphyrin converts a catalytically inactive complex into a highly active catalyst for the oxidation of alkanes with molecular oxygen. The degree of nitration correlates with both the Fe(III)/Fe(II) reduction potential and the catalytic activity.
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    Catalytic oxidation of cyclohexene with molecular oxygen by polyoxometalate-intercalated hydrotalcites (1996)
    Springer
    Catalysis letters 40 (1996), S. 43-45 
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    ISSN: 1572-879X
    Keywords: oxidation ; cyclohexene ; polyoxometalate-intercalated hydrotalcite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Cyclohexene was oxidized with molecular oxygen over transition-metal-substituted polyoxometalate-intercalated hydrotalcites to produce 2-cyclohexene-1-one and 2-cyclohexene-1-ol with high selectivity under mild reaction conditions.
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    A broad spectrum catalytic system for removal of toxic organics from water by deep oxidation using dioxygen as the oxidant (1996)
    Springer
    Catalysis letters 40 (1996), S. 95-99 
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    ISSN: 1572-879X
    Keywords: palladium metal ; oxidation ; toxic organics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In water, metallic palladium was found to catalyze the deep oxidation of a wide variety of functional organics by dioxygen at 80–90°C in the presence of carbon monoxide. Several classes of organic compounds were examined: benzene, phenol and substituted phenols, aliphatic and aromatic halogenated compounds, organophosphorus, and organosulfur compounds. In every case, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 h period. Since the heterogeneous catalyst can be removed by simple filtration, simultaneous water purification and contaminant destruction becomes feasible. For those substrates that are insoluble in pure water, a mixture of water and perfluorobutyric acid was successfully employed as the solvent.
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    X-ray photoelectron spectroscopy of Pd/γ-alumina and Pd foil after catalytic methane oxidation (1995)
    Springer
    Catalysis letters 34 (1995), S. 31-40 
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    ISSN: 1572-879X
    Keywords: palladium ; PdO ; alumina ; methane ; oxidation ; carbon ; XPS ; ellipsometry ; structure sensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Samples of palladium supported onγ-alumina and a palladium foil were used as catalysts for methane oxidation at 550° C. The samples were quenched quickly in the reaction chamber to room temperature in flowing Ar and then transferred in vacuo for XPS analysis. Structure sensitivity was manifest from an increase in PdO stability and a decrease in carbon deposition relative to Pd with increasing particle size. The results were compared with recent ellipsometric data.
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    Mo incorporation in MCM-41 type zeolite (1998)
    Springer
    Catalysis letters 52 (1998), S. 25-29 
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    ISSN: 1572-879X
    Keywords: metallosilicate ; mesoporous ; MCM-41 ; Mo-MCM-41 ; catalysis ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Mo-incorporated MCM-41 has been prepared by direct hydrothermal synthesis. XRD and N2-adsorption measurements showed the characteristics of MCM-41. IR, FT-Raman and UV-VIS DR spectroscopic analyses gave the evidences for the incorporation of Mo in the framework of MCM-41. They are found to be stable and active for cyclohexanol and cyclohexane oxidation reactions with H2O2 as oxidant. Activity of this system has been compared with that of Ti-MCM-41 and molybdena impregnated on pure siliceous MCM-41.
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    Alkene selectivity enhancement in the oxidation of propane on calcium-based catalysts (1999)
    Springer
    Catalysis letters 59 (1999), S. 67-72 
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    ISSN: 1572-879X
    Keywords: propane ; oxidation ; calcium-based catalysts ; tetrachloromethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidation of propane has been investigated in the presence and absence of tetrachloromethane (TCM) on calcium hydroxyapatite (CaHAp), Ca3(PO4)2, CaSO4 and CaO at 723 K. In the absence of TCM, the conversion of C3H8 on CaHAp was 7.7–9.2% during 6 h on-stream while that on Ca3(PO4)2, CaSO4 and CaO was 0.6, 0 and 0.2–0.4%, respectively. The principal products on all catalysts in the absence of TCM were CO and CO2 with small selectivities to C3H6 and C2H4 (both 5–6%) observed on CaHAp. Upon addition of TCM, the selectivity to C3H6 on all catalysts and the conversion of C3H8 on CaSO4 increased while, with increasing time-on-stream, the changes in the conversion and selectivity were dependent upon the nature of the catalysts. XPS and XRD analyses provide evidence for the presence of chlorine in the surface and/or bulk of three of the catalysts, suggesting that chlorinated species on the solids play a role in the selectivity enhancement, but the absence of chlorine from the sulphate demonstrates the dissimilarities of the catalysts in their abilities to sorb and decompose TCM.
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    Synergistic effects in the oxidation of methane on strontium and lead hydroxyapatites (1999)
    Springer
    Catalysis letters 57 (1999), S. 161-165 
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    ISSN: 1572-879X
    Keywords: methane ; oxidation ; strontium hydroxyapatite ; lead hydroxyapatite ; tetrachloromethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidation of methane has been investigated on lead hydroxyapatite (PbHAp), strontium hydroxyapatite (SrHAp) and their binary mixtures at 873 K. PbHAp showed no activity for the oxidation of methane, while SrHAp produced carbon monoxide selectively at 2–4% conversion. On binary mixtures of the hydroxyapatites the conversion of methane and the selectivity to C2 compounds reached values higher than those of the separate constituents of the mixture. With tetrachloromethane in the feed stream a similar synergistic effect was observed with conversions of methane and selectivities to CH3Cl higher on the binary mixtures than those on either SrHAp or PbHAp. The strontium-containing hydroxyapatite appears to play a crucial role in the activation of methane, while the presence of the lead-containing analogue is apparently required for the minimization of undesirable processes involving methyl radicals.
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    The partial oxidation of norbornene over a silver catalyst under steady state conditions (1991)
    Springer
    Catalysis letters 9 (1991), S. 133-143 
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    ISSN: 1572-879X
    Keywords: Norbornene ; oxidation ; silver ; norbornene epoxide ; 3-cyclohexene-1-carboxyaldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The continuous oxidation of norbornene (C7H10) by molecular oxygen over a silver catalyst at 500–573 K has been investigated. In contrast to that observed during the temperature programmed reaction of norbornene and oxygen adsorbed on Ag(110) no norbornene epoxide is formed. Instead benzene is the sole partial oxidation product. A stable selectivity of 20 to 25% with fractional conversions up to 0.8 at 573 K could be obtained by inclusion of 15 to 30 ppm dichloroethane in the feed. Separate experiments withexo-norbornene epoxide showed that in the absence of oxygen it was almost completely isomerised to 3-cyclohexene-1-carboxyaldehyde with production of lesser amounts of norcamphor and norbornene. With oxygen present carbon dioxide and small amounts of benzene were also produced. It is concluded that norbornene epoxide cannot be a gas phase intermediate in the production of benzene from norbornene.
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    Oxidation of acrolein on a multicomponent oxide catalyst (1992)
    Springer
    Catalysis letters 15 (1992), S. 401-404 
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    ISSN: 1572-879X
    Keywords: Acrylic acid ; oxidation ; mixed oxides ; acrolein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Catalytic oxidation of acrolein to acrylic acid has been studied and the optimum composition of the multicomponent catalyst Mo a V b Cu c Fe d O x has been found. The reaction kinetics has been measured.
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    Silicoaluminophosphate number eighteen (SAPO-18): a new microporous solid acid catalyst (1994)
    Springer
    Catalysis letters 28 (1994), S. 241-248 
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    ISSN: 1572-879X
    Keywords: coke ; zeolites ; catalyst regeneration ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract SAPO-18, which has a microporous framework structure related to, but crystallographically distinct from, that of the solid acid catalyst SAPO-34, was synthesized hydrothermally from a silicoaluminophosphate gel containing N,N-diisopropylethylamine as a structuredirecting template. Although both materials have similar Si/(Si + Al + P) ratios, the content of Brønsted acid sites in SAPO-18 is considerably less than that in SAPO-34. As catalysts for methanol conversion to light olefins, SAPO-18 and SAPO-34 have closely similar initial activity and selectivity, but the lifetime of SAPO-18 is distinctly superior to that of SAPO-34.
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    Effect of fluorination of alumina support on activity of platinum catalysts for complete oxidation of benzene (1997)
    Springer
    Catalysis letters 49 (1997), S. 155-161 
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    ISSN: 1572-879X
    Keywords: fluorination ; alumina ; platinum catalysts ; oxidation ; oxidation of benzene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Platinum supported on fluorinated alumina is more active for the total oxidation of benzene than is the catalyst with the same Pt loading supported on hydrophilic unfluorinated alumina. The Pt-F/alumina catalyst contains well-dispersed small Pt particles, in contrast to Pt/alumina. The high dispersion is a consequence of a strong metal-support interaction.
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    Fischer-Tropsch synthesis over iron catalysts (1990)
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    Catalysis letters 7 (1990), S. 241-251 
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    ISSN: 1572-879X
    Keywords: Fischer-Tropsch synthesis ; iron based catalysts ; Fe ; Co ; Ru catalysts ; fixed bed reactors ; fluidized bed reactors ; sulfur poisoning ; oxidation ; coke fouling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Because of the decreased profitability of making synthetic fuels, Sasol intends expanding its production of the higher valued chemicals, in particular waxes and olefins. The advantages and disadvantages of using Fe, Co and Ru catalysts are discussed from the point of view of costs, availability, product selectivity, activity and sensitivity to poisons. The loss of activity and selectivity of iron based catalysts in both fixed and fluidized bed reactors is discussed. The main contributing factors are sulfur poisoning, oxidation and coke fouling. In fixed bed reactors sulfur poisoning and “coke” laydown deactivates the front end of the bed while hydrothermal sintering/oxidation deactivates the back end. In fluidized beds the deposition of large amounts of Boudouard carbon doesnot markedly lower the activity. The smaller catalyst particles end up consisting of small iron carbide entities embedded in a matrix of carbon. The larger catalyst particles consist of cores of inert magnetite surrounded by the carbide/carbon matrix. FT reactor development at Sasol is briefly reviewed.
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    A new process for acetic acid production by direct oxidation of ethylene (1999)
    Springer
    Catalysis surveys from Japan 3 (1999), S. 55-60 
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    ISSN: 1572-8803
    Keywords: acetic acid ; oxidation ; Pd ; heteropoly acid ; ethylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new process for acetic acid production by direct oxidation of ethylene which was established and commercialized is described. The catalyst system consisting of Pd and heteropoly acid exhibits excellent activity and selectivity. The addition of Se or Te to the catalyst system is effective to suppress the formation of carbon dioxide. This new process is applicable to a plant of a wide range of size corresponding to the local demand. Because this new process produces little waste water, it is very friendly to the environment.
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    Oxidation and reduction effects of propane–oxygen on Pd–chlorine/alumina catalysts (2000)
    Springer
    Catalysis letters 64 (2000), S. 163-169 
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    ISSN: 1572-879X
    Keywords: oxidation ; reduction of palladium catalysts ; chlorine effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Pd–chloride precursor salt was used to prepare Pd/Al2O3 catalysts. TPSR measurements showed three distinct reactions for the oxidation of propane on palladium surface under excess of hydrocarbon: complete oxidation, steam reforming and propane hydrogenolysis. Propane oxidation on palladium catalysts was related to the Pd2+ sites observed on Pd/Al2O3 through infrared of adsorbed carbon monoxide. In fresh catalysts reduced by H2, the IR spectra showed the linear and bridge adsorbed CO species on the Pd0 surface. After propane reaction, a new band at 2130 cm-1 related to CO adsorption on Pd2+ species was noted. Carbon monoxide species adsorbed on Pd0 were also observed in all samples after reaction. Our results suggest surface ratios of Pd0/PdO during the propane oxidation. On the other hand, time on stream conversions of the complete oxidation of propane were affected by either the water generated during the reaction or added as a reactant at 10 vol%. The water generated by the reaction helped to eliminate chlorine residues in the form of oxychloride species leading to an increasing of the activity. However, the presence of water into the reaction mixture caused a strong decreasing of the activity. The inhibition mechanism of propane oxidation in the presence of water consisted in the dissociative adsorption of water on palladium sites with the possible formation of palladium hydroxide (Pd–OH) at the surface, diminishing the number of active surface sites. Dynamic fluctuations into the reaction conditions supported the idea that a pseudo‐equilibrium adsorption–desorption of water was reached. After water removal or increasing in the reaction temperature the equilibrium was shifted to the direction of OH–Pd decomposition. This behavior suggests that the inhibitory effect of water is a reversible phenomenon, being a function of the amount of water and the reaction temperature.
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    Preparation of Polyuronic Acid from Cellulose by TEMPO-mediated Oxidation (1998)
    Springer
    Cellulose 5 (1998), S. 153-164 
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    ISSN: 1572-882X
    Keywords: cellulose ; TEMPO ; polyglucuronic acid ; degree of polymerization ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Various cellulose samples were oxidized by 2,2,6,6,-tetramethylpipelidine-1-oxyl radical (TEMPO)-NaBr-NaClO systems, and the effects of oxidation conditions on chemical structures and degrees of polymerization of the products obtained were studied. In the case of regenerated and mercerized celluloses, almost all C6 primary alcohol groups were selectively oxidized to carboxyl groups, and water-soluble polyglucuronic acid (cellouronic acid) sodium salts were obtained almost quantitatively; the degrees of polymerization were influenced greatly by the amount of TEMPO added, and the oxidation time and temperatures. Cellouronic acids prepared from mercerized linter and kraft pulps had size exclusion chromatograms with two separate peaks due to higher and lower molecular weight fractions. On the other hand, only small amounts of carboxyl groups were introduced into native cellulose samples. Since polyglucuronic acids prepared from cellulose by the TEMPO–NaBr– NaClO systems regularly consist of the glucuronic acid repeating unit, differing from the conventional water-soluble cellulose derivatives, they may open new fields of cellulose utilization.
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    The influence of OH groups on the growth of rhodium on alumina: a model study (2000)
    Springer
    Catalysis letters 68 (2000), S. 19-24 
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    ISSN: 1572-879X
    Keywords: aluminum oxide ; hydroxyl groups ; rhodium ; growth ; scanning tunneling microscopy ; infrared spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In order to investigate how the presence of surface hydroxyl groups on oxide surfaces affects the interaction with the supported metal, we have modified a well-ordered alumina film on NiAl(110) by Al deposition and subsequent exposure to water. This procedure yields a hydroxylated alumina surface as revealed by infrared and high-resolution electron energy loss spectroscopy. By means of scanning tunneling microscopy, we have studied the growth of rhodium on the modified film at 300 K. Clear differences in the particle distribution and density are observed in comparison to the clean substrate. While, in the latter case, decoration of domain boundaries as typical defects of the oxide film governs the growth mode, a more isotropic island distribution and a drastically increased particle density is found on the hydroxylated surface. From infrared data, it can be deduced that the growth is connected with the consumption of the hydroxyl groups due to the interaction between the metal deposit and the hydroxylated areas. This finding is in line with photoemission results published earlier.
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    Preparation of metallosilicates with zeolite structure by atom-planting method (1998)
    Springer
    Catalysis surveys from Japan 2 (1998), S. 121-132 
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    ISSN: 1572-8803
    Keywords: zeolite ; metallosilicate ; atom-planting ; modification ; catalysis ; acidity ; shape-selective alkylation ; oxidation ; hydrogen peroxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Atom-planting, a useful method to prepare some metallosilicates having zeolitic structure, was proposed. By treatment of highly siliceous zeolite with metal chloride vapor at selected temperature, metal cation could be introduced into the defect sites (hydroxyl nests) of zeolite framework. By the atom-planting method, some metallosilicates which are difficult to be synthesized by hydrothermal synthesis could be prepared. The vapor phase shape-selective alkylation of ethylbenzene with ethanol, and the liquid phase selective oxidation with hydrogen peroxide on the metallosilicates prepared by atom-planting method were reviewed.
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    Steady-state conversion of methane to C4+ aliphatic products in high yields using an integrated recycle reactor system (2000)
    Springer
    Catalysis letters 66 (2000), S. 1-4 
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    ISSN: 1572-879X
    Keywords: methane ; oxidation ; aliphatic hydrocarbons ; zeolite ; recycle reactor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Conversion of methane in high yields to C4+ nonaromatic hydrocarbons was demonstrated in a recycle system. The principal components of the recycle system included an oxidative coupling reactor with a Mn/Na2WO4/SiO2 catalyst at 800°C for conversion of methane to ethylene, and a reactor with an H-ZSM-5 zeolite at 275°C for subsequent conversion of ethylene to higher hydrocarbons. Total yields of C4+ products were in the range of 60–80%, and yields of C4+ nonaromatic hydrocarbons were in the range of 50–60%.
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    Benzylacetate synthesis by oxyacetoxylation of toluene on Pd–Bi binary catalyst (2000)
    Springer
    Topics in catalysis 13 (2000), S. 243-248 
    Details
    ISSN: 1572-9028
    Keywords: oxidation ; oxyacetoxylation ; alloy ; palladium ; bismuth ; benzylacetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Benzylacetate synthesis from toluene, acetic acid and oxygen on Pd–Bi binary catalyst was studied in the liquid phase. By incorporation of Bi with Pd, both the activity and selectivity were improved. Especially better stability was obtained with the catalyst having Pd/Bi = 3. Deactivation of the catalyst was investigated in detail by XRD, XPS, TEM, elemental analysis, EPMA and so on. Comparing the used catalyst with the fresh one, it was indicated that the main cause of deactivation was the dissolution of Pd into the reaction mixture from the most outer surface of the catalyst. By adopting proper reaction conditions to prevent the Pd dissolution, the catalyst having Pd/Bi = 3 was suggested to be used as an industrial catalyst.
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    The chemisorption of nitric oxide and the oxidation of ammonia at Cu(110) surfaces: a X-ray photoelectron spectroscopy (XPS) and scanning tunnelling microscopy (STM) study (2000)
    Springer
    Topics in catalysis 14 (2000), S. 101-109 
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    ISSN: 1572-9028
    Keywords: nitric oxide ; ammonia ; oxidation ; X-ray photoelectron spectroscopy ; scanning tunnelling microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The dissociative chemisorption of nitric oxide at Cu(110) has been shown to result in rapid ordering of oxygen adatoms as (2×1)O chains oriented along the 〈100〉 direction while the associated nitrogen adatoms are mainly disordered at 295 K. Surface diffusion of the N adatoms, following bond cleavage, is activated and ordering of the (2×3)N strings occurs on heating to 430 K. A number of distinct reaction pathways have been isolated during the oxidation of ammonia resulting in the formation of either chemisorbed imide or nitrogen adatoms. The latter depending on temperature, may exhibit a (2×3)N, a (3×3)N or both structures may exist simultaneously. The concentration of nitrogen in the complete (2×3)N structure has been determined to be 6.6×1014 cm-2, with only a 25% decrease in nitrogen concentration leading to the transformation to the (3×3)N structure. The oxygen atoms at a Cu(110)–O overlayer, and present at the ends of the (2×1) strings terminating in steps, show specific reactivity when exposed to ammonia at 375 K resulting in the “decoration” of the steps with imide species while the oxygens within the (2×1) strings remain unreactive.
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    Direct liquid‐phase side‐chain oxidation of alkylbenzenes over 2 catalyst (2000)
    Springer
    Catalysis letters 65 (2000), S. 181-183 
    Details
    ISSN: 1572-879X
    Keywords: alkylbenzene ; toluene ; ethylbenzene ; xylene ; mesitylene ; p‐ethyltoluene ; cumene ; p‐cymene ; oxidation ; palladium ; 1,10‐phenanthroline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Only the side‐chain oxidation of alkylbenzenes (R–C6H3–R′–R″ R=H, Me, Et, Pri R′=H, Me; and R″=H, Me) by oxygen (35–50 atm, 200)C° is promoted in the presence of [Pd(phen)(OAc)2].
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    Catalysis by porous heteropoly compounds (1998)
    Springer
    Catalysis surveys from Japan 2 (1998), S. 31-44 
    Details
    ISSN: 1572-8803
    Keywords: porous heteropoly compounds ; Pt-promoted heteropoly compounds ; shape selectivity ; water-tolerant catalyst ; hydrogenation ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper attempts to review recent works on catalysis of porous heteropoly compounds. The salts of heteropolyacids having Keggin structure with large cations like Cs+ are porous materials. For Cs hydrogen salts, the pore width can be controlled by the Cs content. Cs2.5H0.5PW12O40 has the largest amount of protons on the surface among the acidic Cs salts and possesses pores with bimodal distribution in the micro and meso region. Efficient performances were demonstrated for acid-catalyzed reactions such as skeletal isomerization of η-butane in solid-gas system, alkylation and acylation in solid-liquid system, and hydrolysis and hydration in solid-water system. A microporous salt, Cs2.2H0.8PW12O40, exhibited reactant shape selectivity towards direct decomposition of esters. Furthermore, an ultramicroporous bifunctional catalyst, Pt–Cs2.1H0.9PW12O40 of which the pore width is around 5 Å, exhibits reactant shape selectivity for hydrogenation of alkenes and oxidation of hydrocarbons, and product shape selectivity for skeletal isomerization of η-butane.
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    URL: http://dx.doi.org/10.1023/A:1019053719634
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    The structural basis for the enhanced oxygenase activity of copper acetate dimers encapsulated in zeolites (2000)
    Springer
    Topics in catalysis 11-12 (2000), S. 359-367 
    Details
    ISSN: 1572-9028
    Keywords: zeozyme ; encapsulated complexes ; copper acetate ; copper dimers ; enzyme mimic ; EPR of copper ; tyrosinase ; oxidation ; oxygenase ; tyrosine oxidation ; phenol oxidation ; hydroxylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxygenase mimicking activity of copper acetate dimers in the regioselective ortho-hydroxylation of L-tyrosine to L-dopa is enhanced on encapsulation in zeolite Y. The structure and magnetic properties of the catalytic active site were characterized by EPR spectroscopy. The spectra of this “zeozyme” reveal the presence of (1) copper acetate dimers in the supercages and (2) isolated Cu(II) ions in the sodalite cages of the zeolite. There are significant differences in the EPR spectra of the “neat” and encapsulated complexes: on encapsulation in zeolite, the Cu–Cu exchange coupling constant, −, increases to 310 from 259 cm−1 for the “neat” complex (i.e., by about 19.7%). Simultaneously the Cu–Cu separation in the dimer, estimated indirectly from the exchange coupling constant, shortens to 2.40 Å in the encapsulated state from 2.64 Å in the “neat” complex. There is, hence, a relatively greater overlap of the metal orbitals of the dimer copper atoms inside the restricted confines of the zeolite cages. The consequent, enhanced, trans axial lability of the phenolate and dioxygen ligands promotes the catalytic oxygenase activity of copper acetate dimers on encapsulation in zeolites. A causal relationship between changes in the structural features of an active site on encapsulation in the zeolite and the corresponding catalytic activity has, thus, been established.
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    The effect of oxide structure and cation reduction potential of vanadates on the selective oxidative dehydrogenation of butane and propane (1992)
    Springer
    Catalysis letters 12 (1992), S. 45-50 
    Details
    ISSN: 1572-879X
    Keywords: Propane ; butane ; alkane ; oxidation ; dehydrogenation ; vanadates ; cation reduction potential ; oxide structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidative dehydrogenation of butane over a series of orthovanadates of cations of different reduction potentials showed a correlation that the selectivity for dehydrogenation decreased with increasing ease of reduction of the cation. The highest selectivity was observed on Mg orthovanadate. Mg pyrovanadate was nonselective for butane oxidation, but was as selective as Mg orthovanadate in propane oxidation. These results were interpreted by the different structures of the two Mg vanadates.
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    The ozone sensitized oxidative conversion of methane to methanol and ethane to ethanol (1992)
    Springer
    Catalysis letters 16 (1992), S. 217-221 
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    ISSN: 1572-879X
    Keywords: Methane ; ethane ; methanol ; ethanol ; ozone ; oxygen atom ; oxidation ; sensitization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The reaction of O2, O3, and CH4 or C2H6 of 7.76, 0.24 and 92% of the hydrocarbon respectively (residence time of 8.8 min) at 1 atm, and 400 °C for CH4 and 300 °C for C2H6 gave CO, CO2, H2O, CH2O and CH3OH from CH4 and in addition CH4, C2H4, CH3CHO and C2H5OH from C2H6. No reaction occurred when O3 was absent indicating that the partial oxidation was sensitized (initiated) by the oxygen atoms formed by the decomposition of ozone.
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    The influence of sulfur dioxide on propane oxidation activity over supported platinum and palladium (1994)
    Springer
    Catalysis letters 30 (1994), S. 41-51 
    Details
    ISSN: 1572-879X
    Keywords: propane ; oxidation ; platinum ; palladium ; sulfur dioxide ; alumina ; zirconia ; activity ; acidity ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Earlier studies have shown that sulfur dioxide and metal-support interaction can strongly influence propane oxidation over platinum. In particular, oxidation activity is enhanced when platinum is supported on sulfated γ-alumina or zirconia compared to γ-alumina. Therefore, it is of interest to compare the performance of palladium under the same experimental conditions. Four model catalysts were examined: Pt/γ-alumina, Pt/zirconia, Pd/γ-alumina and Pd/zirconia. The metal loading was kept at or below 0.05 wt% to emphasize changes in activity attributable to metal-support interaction. Reaction rates were measured with and without sulfur dioxide. Surface sulfation was analyzed by measuring acid strength and evaluating spectra obtained by Fourier-transform infrared spectroscopy. In contrast to platinum, sulfation does not promote propane oxidation on Pd/γ-alumina, and Pd/zirconia is less active than Pd/γ-alumina.
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    Multiple steady-states for the oxidation of aqueous ethanol with oxygen on a carbon supported platinum catalyst (1994)
    Springer
    Catalysis letters 30 (1994), S. 269-277 
    Details
    ISSN: 1572-879X
    Keywords: aqueous ethanol ; multiple steady-state ; oxidation ; platinum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The selective oxidation of aqueous ethanol by dioxygen over a platinum on carbon catalyst was investigated in a three-phase continuously stirred tank reactor at a total pressure of 600 kPa, a temperature of 323 K, a pH of 8.4, and a catalyst concentration of 2.3 kg m−3. Multiple steady-states were obtained by systematic changes in the start-up procedure and variation of the feed concentration of ethanol and partial oxygen pressure in the reactor. The ethanol feed concentration was varied from 100 to 2500 mol m−3 and the partial oxygen pressure from 8 to 120 kPa. On the time scale of the experiments, i.e. 21 ks, two steady-states of the net disappearance rate of ethanol are observed in the ethanol feed concentration range from 500 to 2500 mol m−3 at a partial oxygen pressure of 58 kPa and in the range of partial pressure of oxygen from 8 to 120 kPa at an ethanol feed concentration of 500 mol m−3. Three steady-states are observed in the feed ethanol concentration range from 200 to 400 mol m−3 and a partial oxygen pressure of 58 kPa.
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    Photocatalytic oxidation of substituted toluenes with irradiated TiO2 semiconductor. Effect of zeolite (1995)
    Springer
    Catalysis letters 33 (1995), S. 395-400 
    Details
    ISSN: 1572-879X
    Keywords: TiO2 ; heterogeneous photocatalysis ; oxidation ; substituted toluenes ; zeolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Photocatalytic oxidation of substituted toluenes was investigated on irradiated TiO2 and TiO2 combined with HY15 and HY20 zeolites. In all cases the oxidation occurred in the first step exclusively on either one substituent or the other, but never on both simultaneously. In the presence of a zeolite, photooxidation conversion was higher than that obtained without zeolite.
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    Study of the deactivation mechanism of Al2O3-supported cobalt Fischer-Tropsch catalysts (1995)
    Springer
    Catalysis letters 34 (1995), S. 269-284 
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    ISSN: 1572-879X
    Keywords: Fischer-Tropsch synthesis ; cobalt catalysts ; deactivation ; oxidation ; reduction ; promoters ; rhenium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The influence of water on alumina-supported cobalt catalysts has been studied. The deactivation of supported Co catalysts was studied in a fixed-bed reactor using synthesis gas feeds containing different concentrations of water vapour. Supporting model studies were carried out using H2O/H2 feeds in conjunction with XPS and gravimetry. Rapid deactivation occurs on Re-promoted CO/Al2O3 catalysts when H2/CO/H2O feeds are used, whereas unpromoted CO/Al2O3 shows more stable activity. The results from the gravimetric studies suggest that only a small fraction of the bulk cobalt metal initially present reoxidizes to cobalt oxide during reaction. However, the XPS results indicate significant reoxidation of surface cobalt atoms or highly dispersed cobalt phases, which is likely to be the cause of the observed deactivation. Rhenium is shown to have a marked effect on the extent of reoxidation of alumina-supported cobalt catalysts.
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    Oxidative dehydrogenation of ethane over La1−xSrxFeO3−δ perovskite oxides (1996)
    Springer
    Catalysis letters 38 (1996), S. 189-195 
    Details
    ISSN: 1572-879X
    Keywords: perovskite ; La1−xSrxFeO3−δ ; dehydrogenation ; oxidation ; ethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Catalysts of the composition La1−xSrxFeO3−δ, 0⩽x ⩽1, have been tested for the oxidative dehydrogenation of ethane in the temperature range 300–800°C. The catalyst is active above 400°C, giving a maximum yield of 37% ethylene at 650°C. Above 650°C, synthesis gas was formed together with methane, suggesting that the reforming reaction and thermal cracking of ethane took place. The catalytic data are compared to conductivity measurements on the same material, and a good correlation between the activity and p-type conductivity has been found. In the phase diagram for the system LaFeO3-SrFeO3−δ, a phase separation to two types of (La, Sr)FeO3−δ perovskites was observed in the La/Sr binary composition in the temperature range below 800°C. The phase separation can elucidate the dependency of the catalytic activity on its p-type conductivity.
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    Inhibition of CO oxidation on hydroxyapatite by tetrachloromethane (1996)
    Springer
    Catalysis letters 39 (1996), S. 205-208 
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    ISSN: 1572-879X
    Keywords: oxidation ; hydroxyapatite ; carbon monoxide ; inhibition ; tetrachloromethane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The introduction of tetrachloromethane (TCM) into the feedstream of CO and O2 inhibits the formation of CO2 on hydroxyapatite. TCM interacts with the surface of hydroxyapatite to form its chlorinated analogue, chlorapatite, which suppresses the oxidation of CO to CO2. Thus, in the oxidative coupling of methane the beneficial effects of the addition of TCM to the feedstream result, at least in part, from the suppression of the further oxidation of CO.
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    Oxidation of Cl-modified Ag(111) under UHV conditions and ethylene adsorption on the oxidized surface (1994)
    Springer
    Catalysis letters 26 (1994), S. 109-121 
    Details
    ISSN: 1572-879X
    Keywords: Cl-modified Ag(111) ; oxidation ; phonons ; ethylene adsorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Oxidation of Cl-modified Ag(111) under UHV conditions was investigated using AES, ISS and HREELS. The results showed that Cl-modified Ag(111) can be easily oxidized at 550 K by 1 × 10−6 mbar oxygen which was also heated to 550 K. With HREELS two fundamental vibrations at 600 and 1000 cm−1 were detected for silver oxide and the multiple losses and combination excitations as well. Ethylene adsorption on the oxide was analyzed by HREELS. Surface hydroxyl species was formed at 230 K and stable to above 300 K, which is attributed to silver oxide. Ethylidyne was suggested to form concurrently with hydroxyl species.
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    Pyrene oxidation as a model reaction for characterizing the mechanism of coke oxidation on Y zeolites (1994)
    Springer
    Catalysis letters 28 (1994), S. 53-59 
    Details
    ISSN: 1572-879X
    Keywords: coke ; zeolites ; catalyst regeneration ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The same effect of temperature on the production of CO, CO2 and H2O was found during oxidative treatment of HY zeolites either impregnated with pyrene or coked. Therefore, pyrene oxidation can be used to specify the mechanism of coke oxidation. Three types of reactions can be distinguished: (a) condensation of polyaromatic molecules, (b) oxidation of polyaromatics into aldehydes, ketones, acids and anhydrides and (c) decarbonylation or decarboxylation of oxygenated compounds, all these reactions involving protonic sites.
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    Platinum deactivation: in situ EXAFS during aqueous alcohol oxidation reaction (1998)
    Springer
    Catalysis letters 55 (1998), S. 141-145 
    Details
    ISSN: 1572-879X
    Keywords: platinum ; EXAFS ; catalysis ; catalyst deactivation ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract With a new set‐up for in situ EXAFS spectroscopy the state of a carbon‐supported platinum catalyst during aqueous alcohol oxidation has been observed. The catalyst deactivation during platinum‐catalysed cyclohexanol oxidation is caused by platinum surface oxide formation. The detected Pt–O co‐ordination at 2.10 Å during exposure to nitrogen‐saturated cyclohexanol solution is different from what is observed for the pure oxidised platinum surface (2.06 Å).
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    Insights into surface reactivity: formic acid oxidation on Cu(110) studied using STM and a molecular beam reactor (1998)
    Springer
    Catalysis letters 56 (1998), S. 77-83 
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    ISSN: 1572-879X
    Keywords: catalysis ; combustion ; oxidation ; formic acid ; STM ; molecular beams ; surface diffusion ; surface reactivity ; active sites ; reconstruction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Using a combination of STM and molecular beam reactor data we summarise some important features of a model reaction (formic acid oxidation on Cu(110)) which is of general significance to surface reactivity and to catalysis. Three such features are highlighted here. The first concerns the role of weakly held species (possibly physisorbed) in surface reactions. These species, although of very short lifetime on the surface, can, nevertheless, diffuse over long distances to “find” a sparse distribution of active sites. Thus a very low coverage of oxygen on the surface of Cu(110) increases the sticking probability of all the formic acid molecules which strike the surface to high value (0.82), even though the clean surface is relatively unreactive. The important concept here is the “diffusion circle” or “collection zone” which represents the area of surface visited by the molecule in its short sojourn in the weakly held state. The second theme concerns the concept of the “flexible surface”. We show that the involvement of surface atoms in reactions directs the structure and reactivity for a particular reaction. For formic acid oxidation the liberation of Cu atoms during the removal of oxygen as water leads to gross restructuring of the surface and can lead to “compression” of one reactant (the oxygen in this case) into a lower area, higher local coverage, unreactive state (the c(6×2) oxygen structure). Thirdly, and finally, it is proposed that, for many surface reactions, the surface acts in an analogous way to a solvent, supporting a “dissolved” (highly mobile and fluxional) phase of intermediates at low coverage, which crystallise out above a critical coverage (the 2D “solubility limit”).
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    A study of “superacidic” MoO3/ZrO2 catalysts for methane oxidation (1999)
    Springer
    Catalysis letters 57 (1999), S. 109-113 
    Details
    ISSN: 1572-879X
    Keywords: superacid ; zirconia ; molybdenum oxide ; methane ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A series of zirconia-supported molybdenum oxide catalysts with different molybdenum loadings prepared using conditions reported to generate “superacidity” have been evaluated for their performance as catalysts for methane oxidation. A marked dependence of Mo content on activity has been observed, with the most active material being that with intermediate molybdenum content. 5 wt% MoO3/ZrO2 compares favourably with ZrxCe1-xO2 for methane combustion. The presence of MoO3 is observed to stabilise the tetragonal polymorph of ZrO2 and, as Mo content is increased, dispersed MoO3 crystallites are formed as evidenced by Raman spectroscopy. Temperature-programmed reduction studies evidence differences in the reduction behaviour of the materials as a function of loading. The results indicate that molybdenum oxide supported on monoclinic zirconia gives rise to the most active catalyst. It is tentatively suggested that the formation of a MoO3 monolayer during reaction may be of importance.
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    Partial oxidation of methane to synthesis gas (1990)
    Springer
    Catalysis letters 6 (1990), S. 181-186 
    Details
    ISSN: 1572-879X
    Keywords: Metals for catalysis “syngas” ; oxidation ; nickel ; platinum group metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Partial oxidation of methane to synthesis gas has been carried out over a number of transition metal catalysts under a range of conditions. It is found that the metals Ni, Ru, Rh, Pd, Ir and Pt, either supported on alumina or present in mixed metal oxide precursors, will bring the system to equilibrium. The yield of CO and H2 improves with increasing temperature in the range 650–1050 K, and decreases with increasing pressure between 1 and 20 atm. An excellent yield (∼92%) is obtained with a 4∶2∶1 N2∶CH4∶O2 ratio at 1050 K and atmospheric pressure, with a space velocity of 4×104 hour−1.
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    Formation of a liquid film of AgNO3 on a silver surface (2000)
    Springer
    Catalysis letters 64 (2000), S. 113-118 
    Details
    ISSN: 1572-879X
    Keywords: X‐ray photoelectron spectroscopy (XPS) ; scanning electron microscopy (SEM) ; silver ; oxidation ; surface chemical reaction ; NO ; NO x
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The behavior of a AgNO3/Ag2O/Ag “sandwich” upon heating in vacuum was studied by in situ X‐ray photoelectron spectroscopy (XPS) and ex situ scanning electron microscopy (SEM). The AgNO3/Ag2O/Ag “sandwich” was prepared by exposure of a silver foil to a NO : O2 mixture. The upper layer of the “sandwich” consists of AgNO3 crystals of a mean size between 0.1 and 0.4 μm. Heating at 550 K in vacuum results in melting of the AgNO3 crystals. A liquid film of AgNO3, readily wetting the silver, covers the surface. Cooling below the melting point of AgNO3 leads to the agglomeration of silver nitrate to long islands with a size reaching a few tens of micrometers (μm). The possible effects of AgNO3 liquid‐phase formation on surface processes are discussed.
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    Effect of the catalyst supports on the removal of perchloroethylene (PCE) over chromium oxide catalysts (2000)
    Springer
    Catalysis letters 64 (2000), S. 201-207 
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    ISSN: 1572-879X
    Keywords: chlorinated hydrocarbons ; chromia ; titania ; alumina ; CVOCs ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidation of perchloroethylene (PCE) was investigated over chromium oxide catalysts supported on TiO2, Al2O3, SiO2, SiO2–Al2O3 and activated carbon. The phase of chromium oxide on the catalyst surface is critical for the oxidation of PCE. The catalytic activity of PCE removal enhances as the formation of Cr(VI) species on the catalyst surface increases. The surface area and the type of the catalyst supports were also essential for high performance in the PCE oxidation. In addition, the structure of Cr(VI) on the catalyst surface also plays an important role for the decomposition of PCE. The polymerized Cr(VI) mainly formed by the interaction of metals with the support is the active reaction site for the present reaction system. CrOx/TiO2 reveals the strongest PCE removal activity among the catalysts examined in the present study.
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    Assessment of Hg2+ toxicity to a N2-fixing cyanobacterium in long- and short-term experiments (1992)
    Springer
    BioMetals 5 (1992), S. 149-156 
    Details
    ISSN: 1572-8773
    Keywords: Hg2+ toxicity ; cyanobacterium ; Nostoc calcicola ; growth ; photopigments ; nucleic acids ; photosynthesis ; membrane integrity ; nutrient uptake ; enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Toxicological responses of the filamentous N2-fixing cyanobacteriumNostoc calcicola Bréb. towards Hg2+ were studied to enumerate the decisive lethal events. In low-dose, long-term experiments (0.05–0.25 μm Hg2+, 10 days), photoautotrophic growth was severely inhibited with concurrent loss of photosynthetic pigments (phycocyanin〉chlorophyll α〉carotenoids) and nucleic acids. The termination of growth after a day 4 exposure to 0.25 μm Hg2+ has been attributed to the complete inhibition ofin vivo photosynthetic activity in the cyanobacterium (O2 evolution〉14CO2 incorporation). The elevated Hg2+ concentrations irreversibly damaged the cell membrance as observed under light microscopy, and as indicated by the leakage of intracellular electrolytes and phycocyanin. In high-dose, short-term experiments (0.5–20.0 μm Hg2+, up to 6 h), thein vivo activities of selected enzymes (glutamine synthetase 〉 nitrate reductase 〉 nitrogenase) were less inhibited by Hg2+ than the uptake of nutrient ions (NH 4 + 〉NO 3 − 〉PO 4 3− ).
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    Effects of SO2 on the alkane activity of three-way catalysts (1991)
    Springer
    Catalysis letters 11 (1991), S. 183-190 
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    ISSN: 1572-879X
    Keywords: Three-way catalysts ; sulphur dioxide ; poisoning ; promotion ; oxidation ; steam reforming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Over current Pt-Rh/CeO2-Al2O3 catalysts, the conversion of alkanes occurs by two principal mechanisms: direct oxidation (HC + O2) and steam reforming (HC+H2O). Sulphur dioxide can influence both these mechanisms. Direct oxidation, which predominates when the exhaust-gas is fuel-lean, ispromoted by the adsorption of SOx species by the support. Under fuel-rich atmospheres, the presence of SO2 severelyinhibits steam reforming. The poisoning is associated with the formation of S2− on the platinum and of SO 4 2− on the support, but there is no indication of S-species being retained by the rhodium. It is proposed that each of the two mechanisms is sensitive to a different type of interaction at the metal-support interface. Direct oxidation is enhanced by the transfer of electrons from the precious metal to the support; steam reforming occurs at interfacial sites, which can be blocked by adsorbed SOx species.
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    Oxidation of methanol at copper surfaces (1996)
    Springer
    Catalysis letters 37 (1996), S. 79-87 
    Details
    ISSN: 1572-879X
    Keywords: methanol ; oxidation ; copper ; electron spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The role of preadsorbed oxygen present at Cu(111), Cu(110) and polycrystalline surfaces in the oxidation of methanol has been investigated by X-ray and electron energy loss spectroscopies. In addition to the well established formation of methoxy species and its subsequent decomposition and desorption as formaldehyde, a second reaction pathway to surface formate is present. The latter is temperature dependent being undetectable at 260 K at a polycrystalline surface but occurs at a significant rate at 295 K and above. The limitations of experimental data for methanol oxidation by temperature programmed desorption and molecular beam techniques are discussed.
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    URL: http://dx.doi.org/10.1007/BF00813523
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    Synergistic effects during CO oxidation over mixed oxides. Study of (Fe2O3+SnO2) and (Mn2O3+SnO2) systems (1996)
    Springer
    Catalysis letters 37 (1996), S. 181-185 
    Details
    ISSN: 1572-879X
    Keywords: synergistic effect ; carbon monoxide ; oxidation ; mixed oxides ; iron oxide ; tin oxide ; manganese oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Based on the comparative evaluation of the catalytic activity of Fe2O3, Mn2O3 and SnO2 and their mixed oxides (Fe2O3+SnO2) and (Mn2O3+SnO2), it is shown that the system (Mn2O3+SnO2) shows strong synergistic effects during CO oxidation reaction. Such effects are not observed for the analogous system (Fe2O3+SnO2). Based on the calcination and reduction behaviour of these two mixed oxide systems and the redox potentials of the involved cations, the possible reasons for the observance of synergistic effects for the (Mn2O3+SnO2) system are discussed.
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    URL: http://dx.doi.org/10.1007/BF00807751
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    Non-uniform surface kinetics with two types of sites: the case of ethanol oxidation on molybdenum oxide (1996)
    Springer
    Catalysis letters 39 (1996), S. 67-71 
    Details
    ISSN: 1572-879X
    Keywords: non-uniform surface ; kinetics ; ethanol ; oxidation ; molybdenum oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Temkin's theory of rates of catalytic reactions on non-uniform surfaces is extended to the MoO3-catalyzed oxidation of ethanol to acetaldehyde. Two types of sites are assumed to be present, an oxygen atom site that can be modeled with uniform properties and a metal atom site characterized by non-uniform properties both for ethanol chemisorption to an ethoxide intermediate and the conversion of this intermediate to acetaldehyde. The rate-limiting step is the cleavage of a C-H bond in the absorbed ethoxide intermediate. Non-uniform surface kinetics leads to a kinetic rate expression of the form $$v = kP_{C_2 H_5 OH}^{1 - m} P_{O_2 }^{(1 - m)/4} P_{H_2 O}^{ - (1 - m)/2} $$ . Such a rate expression, withm=0.14, is shown to provide a good fit to kinetic data for the selective oxidation of ethanol on a silica supported molybdenum oxide catalyst.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00813732
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    Kinetics of the gas-solid heterogeneous photocatalytic oxidation of trichloroethylene by near UV illuminated titanium dioxide (1990)
    Springer
    Catalysis letters 4 (1990), S. 345-354 
    Details
    ISSN: 1572-879X
    Keywords: Ultraviolet heterogeneous photocatalysis ; oxidation ; trichloroethylene ; titania ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Kinetics of the gas/solid heterogeneous photocatalytic oxidation of dilute trichloroethylene (TCE) vapors by ultraviolet-illuminated titanium dioxide have been determined using a fixed-bed dynamic photoreactor. Reaction rate dependences on inlet TCE, oxygen and water vapor concentrations were found to consist of both reactant sensitive and insensitive regions. In the reactant sensitive regions, measured limiting apparent reaction rate orders for TCE, oxygen and water vapor are 0.8, 1.7 and — 3, respectively. Water vapor in the reactant stream lowersinitial reaction rates relative to corresponding water free conditions, but is required to sustain photocatalytic activity for extended periods of time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00765320
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    Baeyer-Villiger rearrangement catalysed by titanium silicate molecular sieve (TS-1)/H2O2 system (1996)
    Springer
    Catalysis letters 40 (1996), S. 47-50 
    Details
    ISSN: 1572-879X
    Keywords: Baeyer-Villiger ; titanium silicate molecular sieve ; oxidation ; rearrangement ; titanium peroxo ; triphase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Titanium silicate molecular sieve TS-1 has been found to be an efficient catalyst for Baeyer-Villiger (BV) oxidation of cyclic and aromatic ketones under triphase conditions (solid catalyst along with two immiscible liquid reactants in the absence of any cosolvent), using dilute H2O2. Reactions studied are the oxidation of cyclohexanone and acetophenone. Whereas in the case of cyclohexane,ε-caprolactone, a BV product along with hydroxy and diketones is formed, in the case of acetophenone, phenyl acetate, a BV product along witho- andp-hydroxyacetophenone is formed. The acidic nature of titanium peroxo species, stabilised by water, is proposed to be responsible for such reactions under triphasic reaction conditions.
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    URL: http://dx.doi.org/10.1007/BF00807456
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    Platinum particle size effect on the oxidative dehydrogenation of aqueous ethanol (1996)
    Springer
    Catalysis letters 36 (1996), S. 31-36 
    Details
    ISSN: 1572-879X
    Keywords: ethanol ; kinetics ; oxidation ; oxydehydrogenation ; platinum ; structure sensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effect of the platinum particle size was investigated for the catalytic oxidative dehydrogenation of aqueous ethanol to ethanal at a temperature of 303 K, an ethanol concentration of 260 mol m−3, a partial oxygen pressure 60 kPa, a pH of 9, and an ethanal and ethanoate concentration of 20 mol m−3. A particle size effect on the turnover frequency was observed but only for particle sizes smaller than 2 nm. Hence, the reaction shows a limited structure sensitivity.
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    URL: http://dx.doi.org/10.1007/BF00807202
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    Perfluoroalkylporphyrin complexes as active catalysts for the reaction of isobutane with oxygen and the decomposition of tert-butyl hydroperoxide (1996)
    Springer
    Catalysis letters 36 (1996), S. 69-73 
    Details
    ISSN: 1572-879X
    Keywords: oxidation ; metalloporphyrins ; hydroperoxide decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new family of metalloporphyrin complexes having perfluoroalkyl groups in the meso-positions of the ring are active catalysts for the oxidation of isobutane to tert-butyl alcohol, TBA, and for the decomposition of tert-butyl hydroperoxide to TBA. This discovery extends the limited number of meso-substituents that can be used to enhance catalytic activity and fits the postulate that groups that withdraw electrons from the porphyrin periphery give rise to active catalysts for alkane oxidation. The perfluoroalkyl groups also confer oxidative stability, hydrophobicity and lower cost to the catalyst.
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    URL: http://dx.doi.org/10.1007/BF00807207
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    The preparation and characterisation of nanometre platinum colloids on silicon wafers as model catalysts (1998)
    Springer
    Catalysis letters 50 (1998), S. 49-57 
    Details
    ISSN: 1572-879X
    Keywords: model catalysts ; spin coating ; Pt colloid ; AFM ; XPS ; Si wafer ; particle size ; oxidation ; reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Platinum particles of 2 nm diameter have been immobilised on oxidised silicon wafers by spin coating with colloidal solutions and characterised by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The coverage and dispersion of the Pt colloids on the Si wafer are controlled by varying the concentration and the spin speed. Under optimal conditions mono-dispersed Pt colloids on silicon wafers are prepared. For the Pt colloids immobilised on the Si wafer, the majority of the stabilising ligands are removed through a reduction (with H2 at 200°C) or an oxidation (in air at 300°C) procedure. AFM showed that particle sizes are retained after the reduction procedure, while significant sintering occurs after oxidation. The mechanism of ligand removal was studied using an in situ XPS reaction cell.
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    URL: http://dx.doi.org/10.1023/A:1019062901616
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    The CO2–CeO2 interaction and its role in the CeO2 reactivity (1998)
    Springer
    Catalysis letters 56 (1998), S. 199-202 
    Details
    ISSN: 1572-879X
    Keywords: cerium ; gas carbonic ; propane ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The interaction between CO2 and CeO2 and its role in the surface reactivity of alumina-supported cerium oxide has been studied by programmed thermodesorption (TPD) of CO2 and FTIR spectroscopy. The performance of Ce/Al2O3 systems was then analyzed for the propane oxidation in presence of CO2. The results have shown that the catalytic activity decreased when carbonate species are formed at the surface of CeO2. This behavior was attributed to the presence of CO2 from three different sources: contamination before use, during the handling of the samples, contamination proceeding from the reactants and from CO2 produced by the reaction itself.
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    URL: http://dx.doi.org/10.1023/A:1019098121432
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    Effect of chloride on sintering of Pt/Al2O3 catalysts (1991)
    Springer
    Catalysis letters 8 (1991), S. 327-333 
    Details
    ISSN: 1572-879X
    Keywords: Platinum ; alumina ; oxichloride ; oxidation ; sintering
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Reduced Pt/Al2O3 catalysts with different chloride contents were treated at different temperatures under oxygen flow. TPR and TPD studies of oxidized species show that at low Cl/Pt atomic ratio (⩽1) PtO2 is formed at low temperature (400–500 K) and is totally decomposed (900 K) yielding reduced metallic Pt and inducing metal sintering. At high Cl/Pt atomic ratio (⩾6) formation of stable (up to 1000 K) platinum oxichloride avoids metal sintering.
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    URL: http://dx.doi.org/10.1007/BF00764194
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    A new strategy for alkane oxidation with O2 using N‐hydroxyphthalimide (NHPI) as a radical catalyst (1999)
    Springer
    Catalysis surveys from Japan 3 (1999), S. 27-35 
    Details
    ISSN: 1572-8803
    Keywords: oxidation ; oxygen ; alkane ; N‐hydroxyphthalimide ; radical catalyst
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A practical catalytic method to convert alkanes into the corresponding oxygen‐containing compounds with O2 under mild conditions using N‐hydroxyphthalimide (NHPI) in the presence or absence of a transition metal was developed. Thus, cyclohexane was successfully converted into adipic acid in good conversion and selectivity by a combined catalytic system consisting of NHPI and Mn(acac)2. Lower alkane such as isobutane was converted into t‐butyl alcohol (83%) under 10 atm of air by NHPI‐Co(OAc)2 system. Alkylbenzene such as toluene was oxidized to benzoic acid in high yield (81%) under normal temperature and pressure of dioxygen in the presence of a catalytic amount of NHPI and Co(OAc)2. ESR measurements showed that phthalimide‐N‐oxyl generated from NHPI under dioxygen atmosphere is a key species in this oxidation and functions as a radical catalyst.
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    URL: http://dx.doi.org/10.1023/A:1019059315516
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    Bleaching of cellulose by hydrogen peroxide (1995)
    Springer
    Cellulose 2 (1995), S. 265-272 
    Details
    ISSN: 1572-882X
    Keywords: Hydrogen peroxide ; oxycellulose ; bleaching ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Peroxides are important bleaching agents, industrially, for cellulosic products. They are also used in detergents. Peroxides can degrade cellulose as well as decolorize it and remove stains. Both free radicals and perhydroxyl anions have been suggested as the intermediates in the reactions occurring between cellulosic products and hydrogen peroxide. The proposed mechanisms are reviewed with emphasis primarily on cotton cellulose. Further work is required to establish unequivocally the mechanism of degradation and decolorization of cellulose products.
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    URL: http://dx.doi.org/10.1007/BF00811817
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    Effects of potassium levels over the range occurring in host plants on the growth of an insect herbivore (Manduca sexta) (1991)
    Springer
    Entomologia experimentalis et applicata 61 (1991), S. 59-72 
    Details
    ISSN: 1570-7458
    Keywords: Consumption ; food utilization efficiencies ; growth ; Lycopersicon esculentum ; Manduca sexta ; Nicotiana tabacum ; potassium ; tobacco hornworm ; water regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Third instar tobacco hornworms (Manduca sexta L.: Sphingidae) on low dietary potassium had a lower relative growth rate than individuals on diets with potassium concentrations reflecting those in host-plants, due to decreased consumption rate, lower efficiencies of conversion of ingested and digested food (ECI and ECD), and a prolonged growth/feeding phase. Furthermore, these larvae, when placed on a diet with a moderate potassium concentration through the fourth stadium, ended up being smaller due to lower ECI and less biomass gained, and had a prolonged growth phase, which suggest an irreversible cost of the previous low potassium diet. Third instar hornworms on high potassium diets had lower ECI and ECD, and they had a prolonged growth phase. These individuals, when placed on a moderate potassium diet in the fourth stadium, gained less biomass, than those previously offered hostplant-like-potassium diets. Body potassium concentrations (% dw) at the end of the third stadium were similar among treatment groups. With increasing potassium concentrations in the diet, utilization efficiencies of potassium decreased and potassium concentrations in the frass increased. Correspondingly, water content (% fw) of the newly-molted fourth instar larvae declined with increasing potassium, indicating a passive loss of water during potassium excretion. Low and high dietary potassium reduced survivorship of third instar larvae; fourth instar caterpillars previously fed the low potassium diet also had poor survivorship. We conclude that, within the normal range of potassium concentrations in the hostplants, caterpillar performance is largely unaffected by potassium concentration, but that potassium-poor and potassium-rich diets, such as those hornworms may sometimes experience, can reduce growth and survivorship.
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    URL: http://dx.doi.org/10.1007/BF00367169
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    Electrochemical oxidation of a carbon black loaded polymer electrode in aqueous electrolytes (1999)
    Springer
    Journal of solid state electrochemistry 3 (1999), S. 179-186 
    Details
    ISSN: 1433-0768
    Keywords: Key words Cathodic protection system ; Carbon ; oxidation ; Composite carbon/polymer anode ; Lifetime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The suitability of a polymeric composite material for use as part of an anode structure in a cathodic protection system has been examined. The composite material was a conductive blend (volume resistivity typically 1.5 Ω cm) of carbon black in a polyethylene binder. A long operational lifetime for the material demands that the rate of carbon loss must be low. In the work reported here, electrochemical and in situ analytical techniques were employed to characterise the performance of the material over a wide range of anodic current densities in a variety of aqueous electrolytes. The predominant anodic electrochemical reaction on the polymeric material is CO2 formation in acid and neutral solutions, which causes loss of carbon from the surface and the development of a non-conducting layer of polyethylene. The characteristics of the reaction suggest that it occurs via the discharge of H2O. In alkaline pH, however, the anodic reactions are more complex. A high OH− concentration (pH 12 or higher) favours the formation of oxygen rather than CO2, particularly at low anodic potentials. The presence of CO3 2− in the electrolyte catalyses the evolution of oxygen at pH values as low as 9. The electrochemical formation of oxygen always occurs in parallel with the generation of some humic acid in the solution.
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    URL: http://dx.doi.org/10.1007/s100080050145
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    Lipaemia and liver composition in pregnant rats consuming olive oil and olive oil used for frying (1997)
    Springer
    European journal of nutrition 36 (1997), S. 205-213 
    Details
    ISSN: 1436-6215
    Keywords: Frying ; growth ; liver lipids ; lipaemia ; olive oil ; pregnancy ; rat ; Fritierung ; Wachstum ; Leberfett ; Olivenöl ; Schwangerschaft ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Um Informartionen über den Zusammenhang zwischen der Aufnahme von Fett, das zum Fritieren benutzt wurde, und dem Fetthaushalt während Perioden starken Körperaufbaus zu haben, wurde der Einfluß der Aufnahme von frischem Olivenöl (Gehalt polarer Verbindungen, 2 %; Ölsäure 78,9 mg/100 mg Öl, und Linolsäure 7 mg/100 mg Öl) und von Olivenöl, das 15 mal in Folge für das Fritieren von Kartoffeln benutzt worden war (Gehalt polarer Verbindungen 9 %; Ölsäure 75,8 mg/100mg Öl und Linolsäure 6,2 mg/100mg Öl) während der Gravidität, untersucht. Dazu wurden trächtige Wistar Ratten in zwei Gruppen geteilt, die beide eine isokalorische Diät bekamen, deren Fettanteil 15 % von frischem (unbenutztem) (P1) bzw. fritiertem (benutztem) (P2) Olivenöl stammte mit nicht trächtigen Ratten verglichen. Die Gravidität erhöhte (p〈0,01) die Futteraufnahme, das Körpergewicht, die Gewichtszunahmen und die Futterverwertung. Die Ölqualität beeinflußte dagegen diese Parameter nicht. Während der Gravidität stiegen die Serumwerte der Triglyceride (TG) (p〈0,01) und des Cholesterins (TC) (p〈0,05) an, während die der Phosphatide (PH) sanken (p〈0,01). Ein signifikanter Effekt der Ölqualität und eine Wechselwirkung zwischen Gravidität und Öl wurde für TG und PH festgestellt. Das Gewicht und der Fettgehalt der Leber der trächtigen Ratten stiegen signifikant an (p.〈0.05), Leber TC, TG und PH stiegen während der Gravidität (ungefähr um das 3-fache der Ausgangswerte), aber es traten keine signifikanten Unterschiede zwischen der Aufnahme von benutztem und nicht benutztem Öl (P2 vs P1) auf. Die Ergebnisse zeigen, daß die Aufnahme von leicht verdorbenem Olivenöl als alleinige Fettquelle der Nahrung keine besonderen Folgen für die Gravidität hat, was die Gewichtszunahme der Mütter und der Feten, die Lipämie und die Zusammensetzung des Leberfetts betrifft.
    Notes: Summary The effect of the consumption of unused olive oil (polar content, 2 %; oleic acid, 78.9 mg/100 mg oil, and linoleic acid 7 mg/100 mg oil) and olive oil used discontinuously for frying potatoes 15 times (polar content, 9 %; oleic acid, 75.8 mg/100 mg oil and linoleic acid 6.2 mg/100 mg oil) was studied in pregnant rats with the aim of better understanding the relationship between the consumption of fat used in frying and lipid metabolism during periods of intense anabolism. Trials were performed in pregnant Wistar rats, divided into 2 groups and fed isocaloric diets in which the fat content (15 % wt/wt) consisted of unused olive oil (P1) or oil previously used for frying (P2), and the results were compared with those of nonpregnant rats fed unused olive oil (NP1) and olive oil used for frying (NP2). Pregnancy increased (p〈0.01) food intake, body weight, weight gain, and food efficiency ratio (P2 vs NP2 and P1 vs NP1, respectively), but the treatment of oil included in the diets did not alter these parameters. Gestation significantly increased the serum triglyceride (TG) (p〈0.01) and total cholesterol (TC) (p〈0.05) concentrations and diminished that of phospholipids (PH) (p〈0.01). A significant effect of the type of oil consumed and a pregnancy x oil interaction on Tg and PH levels was observed. The weight of the liver and its fat content increased significantly (p〈0.05) as a result of pregnancy. Liver TC, TG, and PH increased (approximately 3 times the original values) during gestation, but no significant differences due to the intake of used or unused oil (P2 vs P1) were observed. The results indicate that the consumption of moderately altered olive oil, as the sole source of fat, does not alter the effect of pregnancy on the mothers' weight gain, lipaemia, and hepatic fat composition to any important degree.
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    Effects of porcine somatotropin on the chemical body composition and fat quality in growing-finishing pigs (1997)
    Springer
    European journal of nutrition 36 (1997), S. 294-298 
    Details
    ISSN: 1436-6215
    Keywords: Body composition ; fat ; growth ; somatotropin ; pig ; Körperzusammensetzung ; Fett ; Wachstum ; Somatotropin -Schwein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung An 78 männlichen Kastraten und weiblichen Schweinen der Kreuzung Pietrain x (Deutsches Edelschwein x Deutsche Landrasse) wurden Untersuchungen zum Einfluß einer porcinen Somatotropin (pST)-Behandlung während des Wachstums auf die chemische Körperzusammensetzung der Tiere, das Adipozyten-Wachstum und das Fettsäure-Profil des Rückenspecks untersucht. Die intramuskulären Injektionen (1 oder 3 mg pST) wurden täglich ab durchschnittlich 65 kg Lebendgewicht bis zum Schlachten verabreicht. Nach der pST-Behandlung wurden bei den Kastraten in allen untersuchten Merkmalen signifikante Unterschiede festgestellt, während sich bei den weiblichen Tieren nur leichte Reaktionen zeigten. Das pST verursachte eine Zunahme des Wasserund Proteingehaltes bei gleichzeitiger Reduzierung des Lipidgehaltes besonders in den fettreichen Körperteilen der Tiere. Im Rückenspeck war der Gehalt an ungesättigten Fettsäuren erhöht und der Fettzelldurchmesser erniedrigt.
    Notes: Summary Seventy eight growing-finishing pigs (male castrates and females) of the cross-breed Pietrain x (Large White x German Landrace) were used to investigate the effects of pST treatment on the chemical composition of the body, the growth of adipocytes, and the fatty acid profile of the backfat. Intramuscular injections (1 or 3 mg pST) were administered daily from an average weight of 65 kg up to slaughter. After pST treatment significant changes in all studied characteristics were observed in barrows, whereas the females exhibited very small responses. The pST caused an increase of water and protein contents and a simultaneous decrease of lipid content especially in body parts rich in fat. Furthermore, the proportion of unsaturated fatty acids increased and the fat cell diameter decreased in the backfat.
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    Short-term dynamics in protein and amino acid metabolism (1997)
    Springer
    European journal of nutrition 36 (1997), S. 336-339 
    Details
    ISSN: 1436-6215
    Keywords: Amino acids ; protein ; metabolism ; meal feeding ; oxidation ; breath test ; Aminosäuren ; Protein ; Stoffwechsel ; Fütterung ; Oxidation ; Atemtest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Die aktuellen Mengen an freien Aminosäuren im Blut reichen nur aus, um die Ganzkörper-Proteinsynthese für einige Minuten aufrecht zu erhalten. Das zeigt, daß die freien Aminosäurenkonzentrationen in der Zirkulation klein und konstant gehalten werden im Vergleich zu den Mengen der Aminosäuren, die täglich aufgenommen und über die Körperproteine umgesetzt werden. Das Verschwinden der Aminosäuren exogenen oder endogenen Ursprungs aus dem freien Aminosäuren-Pool, findet hauptsächlich durch die Proteinsynthese und den Aminosäurenabbau statt. Die Partitionierung der Nahrungs-Aminosäuren zwischen diesen beiden Prozessen im Kurzzeitbereich werden als bedeutsam für die Ökonomie der Ganzkörper-Aminosäuren angesehen. Eine Verbesserung der Aminosäurenökonomie könnte durch solche nutritiven Maßnahmen erreicht werden, welche die Clearance der Nahrungsaminosäuren durch die Proteinsynthese anstelle des Aminosäurenabbaus begünstigen. Diese nutritiven Maßnahmen sollten sich an den „Schwellenwerten“ des Abbaus der individuellen Aminosäuren orientieren.
    Notes: Summary Actual amounts of free amino acids in the blood are sufficient to support whole body protein synthesis for some minutes only. This indicates that the levels of free amino acids in the circulation are kept small and constant relative to the amounts of amino acids supplied by daily intake and turnover of body proteins. The clearance of the amino acids originating from either endogenous or exogenous sources is mainly due to protein synthesis and metabolic degradation. The partitioning of dietary amino acids between these processes, on the short term, is supposed to play an important role in whole body amino acid economy. Therefore whole body amino acid economy could be improved by nutritional measures that favour the clearance of dietary amino acids by protein synthesis instead of by metabolic degradation. These nutritional measures should to be focused on threshold values for metabolic degradation of individual amino acids.
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    Manganese(III) oxidations of benzoylhydrazine, aroxyacetylhydrazine, semicarbazide, thiosemicarbazide and their derivatives in pyrophosphate media (1994)
    Springer
    Microchimica acta 113 (1994), S. 61-69 
    Details
    ISSN: 1436-5073
    Keywords: manganese(III) ; pyrophosphate ; oxidation ; hydrazines ; hydrazides ; carbazides ; potentiometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Manganese(III) ion was stabilised in weakly acidic solution by means of pyrophosphate. Conditions for the quantitative oxidation of hydrazine, benzoylhydrazines, aroxyacetylhydrazines, semicarbazide, semicarbazones, thiosemicarbazide and thiosemicarbazones were investigated by titrimetric and potentiometric methods. The stoichiometries of these oxidations were pH-dependent. At pH 5 benzoyl hydrazines were oxidised by donating two electron each, the nitro derivative being the sole exception to show a three-electron change. Aroxyacetylhydrazines, semicarbazide and semicarbazones underwent three-electron oxidations. The free radical nature of these reactions was illustrated. Thiosemicarbazides reacted faster than semicarbazides. Metal complexes of thiosemicarbazide also yielded stoichiometric results, indicative of the number of TSC ligands in the complex. The oxidation products have been identified. At pH ⩽ 1 these reactions conformed to different stoichiometries.
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    URL: http://dx.doi.org/10.1007/BF01243138
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    Estimation of mercaptans with 1-chlorobenzotriazole (1990)
    Springer
    Microchimica acta 102 (1990), S. 271-276 
    Details
    ISSN: 1436-5073
    Keywords: mercaptans ; oxidation ; disulphide ; Chlorobenzotriazole ; potentiometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A simple but accurate potentiometric method for the estimations of mercaptans in 0.01M perchloric acid has been developed, based on their oxidation with 1-Chlorobenzotriazole. Quantitative oxidation solely to the disulphide stage is ensured by using critical amounts of methanol, acetonitrile and potassium iodide. Chloride, mercury(II) and copper(II) interfere. A back-titration procedure can also be used. The oxidation products have been identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244768
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  • 97
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    The oxidation behaviour of niobium containing γ-TiAl based intermetallics in air and argon/oxygen (1995)
    Springer
    Microchimica acta 119 (1995), S. 23-39 
    Details
    ISSN: 1436-5073
    Keywords: oxidation ; titanium aluminide ; SNMS ; niobium effect ; oxygen tracer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The oxidation behaviour of γ-TiAl based alloys with different Nb contents (2–10 At.%) was investigated in air and in argon-20% oxygen at 900 °C using thermogravimetric analysis. The oxide scales were characterized by a combination of optical microscopy, SEM/EDX and X-ray diffraction analyses. Although in all studied cases the presence of niobium improves the oxidation resistance of γ-TiAl, the oxidation kinetics, scale morphology and composition in air differed strongly from that in argon-oxygen. In air the oxidation resistance increases with increasing niobium-content. In Ar/O2 the niobium dependence is far more complex because internal oxidation occurs which is favoured by the presence of niobium. SNMS analysis revealed that the differences in behaviour in the two atmospheres are related to the formation of Ti-rich nitride at the scale/alloy interface during air oxidation. The positive effect of niobium on the oxidation resistance of γ-TiAl is mainly caused by a decrease of the transport processes in the heterogeneous TiO2/Al2O3-surface scale. Nitride formation and/or niobium enrichment at the scale/alloy interface also affect the oxidation behaviour, however these factors are believed to be the result of the decreased transport processes rather than the main reason for the niobium effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01244851
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  • 98
    Electronic Resource
    Electronic Resource
    C60: A host lattice for the intercalation of oxygen? (1997)
    Springer
    Microchimica acta 125 (1997), S. 401-406 
    Details
    ISSN: 1436-5073
    Keywords: fullerenes ; intercalation ; oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The investigation of structural and electronic properties of the novel family of fullerenes depends on the existence of pure reference materials. Sublimation of the van-der Waals solids is a suitable purification method. Little attention has been paid to the question about the air stability of such sublimed samples in form of crystals or thin films. A combination of thermal desorption spectroscopy, thermal analysis and diffuse reflectance FT-IR spectroscopy is used to show the extent to which oxygen from dry air is intercalated into fullerenes and which detrimental reactivity occurs from attempts to thermally remove („nneal”) air-exposed samples. The conclusion is that any fullerene sample exposed to air will be transformed in part into a polymeric non-fullerene carbon upon thermal treatment to above 400 K irrespective of its initial purity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01246218
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  • 99
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    Electronic Resource
    Sources of Sectoral Growth in an Economy Wide Context: The Case of U.S. Agriculture (1997)
    Springer
    Journal of productivity analysis 8 (1997), S. 293-310 
    Details
    ISSN: 1573-0441
    Keywords: growth ; USagriculture ; externalities ; spill-overs ; public R and D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract Growth in U.S. agriculture is linked to the non-farm economy through domestic terms of trade and factor market adjustments. With almost stable input growth, the relatively large contributions from growth in Total Factor Productivity (TFP) are passed on to intermediate and final consumers in the form of declining real prices for primary farm products. The resulting net growth in the real value of farm output (GDP) is relatively low (0.25% per annum). The decomposition of TFP suggests that public agricultural stock of knowledge and infrastructure are “robustly” associated with TFP growth, while spill-overs from private agricultural and economy wide research and development (R and D) are positive but, relatively small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007759705652
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  • 100
    Electronic Resource
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    Optimal concentration of ammonium ion in a minimal synthetic medium for the growth of Candida albicans (1991)
    Springer
    Mycopathologia 113 (1991), S. 139-142 
    Details
    ISSN: 1573-0832
    Keywords: Candida albicans ; ammonium ; physiology ; medium ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Candida albicans strain B 311-10 with and without starvation was cultivated in the minimal synthetic medium of Shepherd et al. [18], modified without biotin, aminoacids, low glucose concentration [20] and with decreasing amounts of (NH4)2SO4, to determine the optimal growth requirement for this strain. All the experiments were carried out under sterile conditions at 25 °C in a thermostat with initial O.D.s (675 nm) of 0.500 and 0.100. Cell growth was generally monitored everyday for six days with a spectrophotometer by determining the absorbance of the cultures at 675 nm. All the experiments were repeated three times and a statistical analysis of the data with a probability of 99% and 1% of error was performed to confirm the validity of the results. Best growth was obtained with starved cells at an initial O.D. of 0.100 and with a 0.1 g/L concentration of (NH4)2SO4. At this concentration, the growth of C. albicans B 311-10 was best between the first and the fourth day with the maximum at the third day. With (NH4)2SO4 concentrations of 0.05 and 0.5 g/L, cell growth was the same.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00436116
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