ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Springer  (46)
  • 1995-1999  (39)
  • 1935-1939  (7)
Collection
Keywords
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    The use of 29Si NMR to characterize the sol-gel synthesis of cordierite (1997)
    Springer
    Fresenius' journal of analytical chemistry 357 (1997), S. 514-516 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  Cordierite powder was synthesized via different sol-gel procedures. The use of 29Si NMR spectra of all stages beginning from tetraethoxysilane (TEOS) up to final ceramic powder material is discussed. In the early stages of the sol-gel process all oligomeric structure units can be identified. Spectra of the higher condensed sols only allow the quantification of Qn-groups. MAS spectra of gels heated up to 750 °C show no fine structure to be evaluated. Spectra of samples heated to 1250 °C indicate a sluggish disorder-order transformation from hexagonal α-cordierite to orthorhombic cordierite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Interindividual variation in the enzymatic 15-keto-reduction of 13,14-dihydro-15-keto-prostaglandin E1 in human liver and in human erythrocytes (1997)
    Springer
    European journal of clinical pharmacology 52 (1997), S. 147-153 
    Details
    ISSN: 1432-1041
    Keywords: Key wordsProstaglandin E1 ; Carbonyl reductase; 13 ; 14-dihydro-15-keto-PGE1 ; 13 ; 14-dihydro-PGE1 ; human ; liver ; erythrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The therapeutic response to PGE1 is highly variable, and a contribution by variable formation of its active tertiary metabolite PGE0 is in question. Hence, the objective of this study was to assess the person-to-person variation of the reduction of the inactive intermediate metabolite 15-KD PGE1 by human liver and human erythrocytes in forming the active metabolite PGE0. Methods: Source of enzyme was lysed erythrocytes from 29 donors, and a bank of 37 donor livers including specimens from 15 children. Tritium-labelled 13,14-dihydro-15-keto-prostaglandin E1 (15-KD PGE1) was used at low nanomolar concentrations and found to be converted almost exclusively to the more polar compound 13,14-dihydro-prostaglandin E1 (PGE0) by an NADPH-dependent carbonyl reductase. The identity of the product PGE0 was established by comparison of its chromatographic and mass spectral characteristics with authentic PGE0. Results: Lysed erythrocytes had readily measurable enzymatic activity; differences between the preparations from 29 subjects were very small with only a twofold range of variation. In contrast to lysed erythrocytes, intact erythrocytes did not catalyse the reaction so that the erythrocyte activity should be medically immaterial. 15-KD PGE1 15-ketoreductase activity of liver cytosol averaged 61.1 fmol · min−1 · mg−1 protein in preparations from 37 human livers. Individual activities varied over an almost tenfold range, with indications of a non-normal distribution. Kinetic studies of selected specimens showed substantially different Vmax values but indistinguishable k M values, suggesting that the individual variation in 15-KD PGE1 15-ketoreduction is the result of differences in enzyme concentration rather than of structural enzyme variations. The activity in 15 livers from children was significantly lower than in those from adults. Inhibition data suggest that both the liver and the erythrocyte enzymes belong to the class of carbonyl reductases. Conclusions: The variations in hepatic enzyme activity may be expected to affect the transformation of 15-KD PGE1 to the active metabolite PGE0 in vivo. The clinical significance remains to be explored.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050264
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Chemical ozone loss in the Arctic vortex in the winter 1995–96: HALOE measurements in conjunction with other observations (1998)
    Springer
    Annales geophysicae 17 (1998), S. 101-114 
    Details
    ISSN: 0992-7689
    Keywords: Chemical ozone loss (Arctic vortex 1995–96; halogen chemistry)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Severe chemical ozone loss has been detected in the Arctic in the winter and spring of 1995–96 by a variety of methods. Extreme reductions in column ozone due to halogen catalysed chemistry were derived from measurements of the Halogen Occultation Experiment (HALOE) on board the Upper Atmosphere Research Satellite in the Arctic vortex. Here, we discuss further aspects of the HALOE observations in the Arctic over this period. Potential problems, both in the data themselves and in the methodology of the data analysis are considered and the reason for the differences between the Arctic ozone losses deduced from HALOE data version 17 and 18 is analysed. Moreover, it is shown that HALOE measurements in the Arctic in winter and spring 1995–96 compare well with observations by other ground-based and satellite instruments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-999-0101-x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Catechol 2,3-dioxygenase from the thermophilic, phenol-degrading Bacillus thermoleovorans strain A2 has unexpected low thermal stability (1999)
    Springer
    Extremophiles 3 (1999), S. 185-190 
    Details
    ISSN: 1433-4909
    Keywords: Key words Catechol 2 ; 3-dioxygenase ; Bacillus thermoleovorans ; Thermophilic ; Enzyme stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Catechol 2,3-dioxygenase from the thermophilic Bacillus thermoleovorans A2 was purified and characterized. The catechol 2,3-dioxygenase has a molecular mass of 135 000 Da and consists of four identical subunits of 34 700 Da. One iron per enzyme subunit was detected using atom absorption spectroscopy. Enzyme activity was not inhibited by EDTA, suggesting that the iron is tightly bound. Addition of hydrogen peroxide to the enzyme completely destroyed activity, indicating that the iron was in the divalent state. The isoelectric point of the enzyme was 4.8. The enzyme displayed optimal activity at pH 7.2 and 70°C. The half-life of the catechol 2,3-dioxygenase at the optimum temperature was 1.5 min under aerobic conditions and 10 min in a nitrogen atmosphere. This stability of the enzyme is comparable to the stability of the enzyme from the mesophilic Pseudomonas putida mt-2. The stability of the cloned enzyme in E. coli extracts was identical to the stability in wild-type extracts, suggesting that no stabilizing factors were present in Bacillus thermoleovorans A2 In whole cells the half-life of the enzyme at 70°C was approximately 26 min, when protein synthesis was disrupted by chloramphenicol; however, the activity remained constant when protein synthesis was not inhibited. From these results we concluded that catechol 2,3-dioxygenase from Bacillus thermoleovorans A2 is not particularly thermostable, but that the organism retains the ability to degrade phenol at high temperatures because of continuous production of this enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007920050115
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    A Microtomographic System for the Nondestructive Evaluation of Bone Architecture (1996)
    Springer
    Calcified tissue international 58 (1996), S. 24-29 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Microtomography — Computed tomography — Bone structure — Bone strength — Osteoporosis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Microtomography (micro-computed-tomography, μ-CT) is a method to image and quantify trabecular bone. It has the capability to address the role of trabecular architecture on the mechanical properties of bone and to study trabecular bone remodeling. The system described in this work is based on a compact fan-beam type tomograph that can work in spiral scanning or multislice mode. An X-ray tube with a microfocus is used as a source, a CCD-array as a detector. Samples with diameters from a few millimeters to a maximum of 14 mm can be measured, typically, bone biopsies with a diameter of 8 mm and a length of approximately 10 mm are measured. Spatial resolution is 28 μm. Usually the volume of interest contains 4 × 4 × 4 mm3 and is represented in 14 × 14 × 14 μm3 voxels. 3D stereological indices are extracted according to the standard definitions used in histomorphometry. Triangular surface representation is effected with an extended marching cube algorithm and forms a convenient basis for finite element analysis. Microtomographic measurements may be employed to ``calibrate'' lower-dose, lower-resolution images in vivo as well as to nondestructively assess unprocessed surgical bone biopsy specimens. These specimens remain intact for mechanical or histological testing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900006
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Prevalence of Trabecular Microcallus Formation in the Vertebral Body and the Femoral Neck (1997)
    Springer
    Calcified tissue international 60 (1997), S. 479 -484 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Trabecular microcallus formation — Vertebra — Femur — Histomorphometry — Bone density — Osteoporosis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Trabecular microcallus formation (TMF) has been described previously in the human vertebra and femur, but the difference in TMF prevalence at these two sites has not been studied and the role of TMF remains controversial. In this study, the 4th lumbar vertebra (L4) and right proximal femur were removed from 27 male and 23 female cadavers. A 2 cm cube cut from the center of L4 and a 1 cm-thick slice cut from the femoral neck were cleaned, defatted, and dried. The apparent density of the L4 cubes was determined as dry weight/bulk bone volume. Using a dissecting microscope at low magnification (4–60×), TMF were identified and counted in both the vertebral and femoral samples. A 8 mm diameter core was then cut from the center of the L4 cubes in the vertical direction, and selected histomorphometric parameters of the core were evaluated with an X-ray microcomputed tomography system (μ-CT). There was a significantly greater prevalence of TMF in vertebral cubes (82%) than in the femoral slices (11%) (P 〈 0.001). TMF prevalence did not differ significantly between males and females, but the mean number of TMF in the vertebra was significantly (P 〈 0.05) greater in females (15.0/vertebra) than in males (7.7/vertebra). In the vertebra, the majority of the observed TMF were in vertical trabeculae. Subjects over 60 years old had a higher TMF prevalence than those under 60 years old (P 〈 0.01). TMF numbers increased with decreasing apparent density (P 〈 0.05), whereas no significant correlations were found between TMF and bone volume (BV/TV), trabecular number (Tb.N), or trabecular thickness (Tb.Th) as assessed by μ-CT. In two fractured vertebra, very few TMFs (2 and 4, respectively) were observed. These results demonstrated that the occurrence of TMF is strongly related to the anatomical site, probably due to differences in the applied loads and the trabecular structure between sites. The results were consistent with the hypothesis that TMF is a mechanism acting to maintain bone strength, but further studies are needed to clarify this important issue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900266
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Validity and reproducibility of benthic cover estimates made during broadscale surveys of coral reefs by manta tow (1999)
    Springer
    Coral reefs 18 (1999), S. 353-356 
    Details
    ISSN: 1432-0975
    Keywords: Key words Coral Reef ; Manta tow ; Survey ; Benthic video ; Observer ; Comparisons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract  There is limited information on the validity and reproducibility of estimates of benthic cover from manta tow surveys. To address this, benthic cover estimates from the same reef area were compared (i) among observers and (ii) with an independent assessment using under-water video. Benthic cover was classified into 11 categories. There was generally unbiased agreement within one cover category, both among observers (89%) and for comparisons between manta tow and video (86%). While estimates of dead coral cover were reproducible, they were not valid because the concordance between observer estimates and video estimates was not greater than would be expected by chance. Manta tow estimates of the cover of sand and rubble were biased in that they consistently overestimated sand and rubble cover in comparison with estimates from video. The results indicate that manta towing is generally effective for the broadscale estimation of live coral cover, providing observers receive adequate training.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003380050212
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Visualization and measurement of helicopter rotor flow with swept back tip shapes at hover flight using the “flow visualization gun” time line technique (1996)
    Springer
    Experiments in fluids 21 (1996), S. 161-169 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The Flow Visualization Gun (FVG), a novel time line visualization technique, has been used to investigate the flow field of a helicopter rotor with swept back tip shape in hover flight condition. After introducing the FVG-technique, the paper presents some visualization photographs of the rotor blade tip vortices and the rotor downwash. Using orthogonal sets of flow photographs and digital image analysis, the 3-dimensional time line displacement within the flow and the tip vortex structure are determined. The data of 16 time line experiments are interpolated in space and time to obtain velocity data on an evenly spaced 3-dimensional grid. Vorticity contour plots of the flow field show the complex arrangement of the tip vortices of the blade itself and of the preceding blade and some additional vorticity in the direct wake which may form a secondary vortex. Understanding and control of this vorticity distribution is important for the design of new efficient tip shapes. While the FVG technique has been used so far for qualitative investigation of complex flow patterns at local velocities of up to 20 m/s, a good comparison to laser velocimetry data validates the technique as an interesting tool for both qualitative and quantitative investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191687
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Information theory and systematic toxicological analysis in “general unknown” poisoning cases (1997)
    Springer
    Fresenius' journal of analytical chemistry 358 (1997), S. 785-792 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract  If qualitative analysis is aimed to detect large, imprecisely confined groups comprising hundreds or thousands of compounds – like during the analysis of questionable poisoning cases without direct hints, the so called “general unknowns”–, the evaluation of the identification certainty becomes equally important like the associated estimation of the necessary information capacity of the analytical procedures to be applied [1–4]. On this basis, the authors have outlined factors, which influence the usable information provided by analytical principles or procedures depending of the number and types (analytical categories, differences and similarities, detectability) of the analytes to be detected or included. A correlation between the usable information (excess or deficiency) and the probability of failing identifications is defined, and the information loss by interfering analytical signals is discussed. The concepts of discrimination power DP, identification power IP, and mean list length MLL [4–7] are associated with these considerations. Examples of analytical tasks in this “general unknown” environment of toxicological analysis are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050510
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Detection and identification of individual antigen molecules in human serum with pulsed semiconductor lasers (1997)
    Springer
    Applied physics 65 (1997), S. 427-431 
    Details
    ISSN: 1432-0649
    Keywords: PACS: 42.80; 85.30; 878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: -11  M without separation steps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003400050292
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...