ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

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Ballistic-Electron-Emission Microscopy: A Nanometer-Scale Probe of Interfaces and Carrier Transport (1996)

Bell, L D ; Kaiser, W J

Palo Alto, Calif. : Annual Reviews

Annual Review of Materials Research 26 (1996), S. 189-222

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ISSN: 0084-6600

Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1146/annurev.ms.26.080196.001201

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2

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Micromachined infrared sensors using tunneling displacement transducers (1996)

Kenny, T. W. ; Reynolds, J. K. ; Podosek, J. A. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Review of Scientific Instruments 67 (1996), S. 112-128

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ISSN: 1089-7623

Source: AIP Digital Archive

Topics: Physics , Electrical Engineering, Measurement and Control Technology

Notes: Uncooled infrared sensors are important for a number of technological and scientific measurements. We have designed, built, and tested a new uncooled infrared sensor which is made by silicon micromachining. This infrared sensor uses a tunneling displacement transducer to detect the thermal expansion of a small volume of trapped gas. Prototype devices based on this design have been operated with NEP better than 3×10−10 W/(square root of)Hz at 25 Hz, which is competitive with the best comparably sized uncooled sensors available. This article will describe the design, fabrication, and operation of all elements of this sensor. © 1996 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.1146559

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3

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SO2-dependent cation competition and compartmentalization in Norway spruce needles (1996)

SLOVIK, S. ; HÜVE, K. ; KINDERMANN, G. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Plant, cell & environment 19 (1996), S. 0

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ISSN: 1365-3040

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Ion contents in needles from Norway spruce trees [Picea abies (L.) Karst.] growing in Würzburg and in the SO2-polluted Erzgebirge mountains were analysed to quantify cations which accumulate together with sulphate. In Würzburg there was a positive correlation of potassium (0.680 ± 0.300 Eq Eq−1 SO4−2), magnesium (0.415 ± 0.111 Eq Eq−1 SO4−2) and zinc (0.059 ± 0.006 Eq Eq−1 SO42−). In the Erzgebirge, potassium was also the stoichiometrically most important cation (0–887 ± 0–180 Eq K+ Eq−1 SO42−). All other correlations examined were weak or statistically non-significant. At both sites the calcium content of spruce needles did not depend on the sulphate content. The lack of a role for Ca2+ in neutralizing sulphate is a consequence of the presence of free oxalic acid in needles. Soluble oxalic acid precipitates Ca2+, which thereby becomes unavailable as a counterion for SO42−. The activity coefficients of Ca2+ and oxalate2−, and the solubility product of Ca-oxalate, were determined from in vivo data. It is concluded that the chronic accumulation of atmospheric sulphate in spruce needle vacuoles depletes available potassium and thereby strongly interferes with spruce growth and canopy turnover. This leads to impaired spruce vitality, even at sites where acute SO2 disease symptoms are absent.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-3040.1996.tb00418.x

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4

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Nitrate reductase in Zea mays L. under salinity (2000)

Baki, G. K. Abd-El ; Siefritz, F. ; Man, H.-M. ; [et al.]

Oxford, UK : Blackwell Science Ltd

Plant, cell & environment 23 (2000), S. 0

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ISSN: 1365-3040

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Young maize seedlings (Zea mays L. cv.Giza 2) were exposed to moderate salinity in hydroponic culture. NADH-nitrate reductase (NR) activity (E.C. 1·6.6·1), NR activation state, NR-mRNA-steady state levels and major solute contents in leaves and roots were investigated. With increasing external salt concentration, Na+, Cl−, sugars, amino acids and quarternary ammonium compounds accumulated in leaves and roots, with concentrations in leaves exceeding those in roots. The nitrate content of leaves decreased, but increased in roots. The diurnal pattern of NR activity and of NR-mRNA was also changed under salinity, but the NR activation state was not affected. In the first light phase, maximum NR activity increased rapidly in leaves of control plants, but was much slower in leaves from salinized plants. Thus, integrated over the whole day, the NR activity of salt-stressed plants was lower than in control plants. NR transcript levels of control plants were low in the early night phase, started to increase in the second night phase, followed by a distinct peak at 2 h into the light period. This large ‘early morning peak’ of NR-mRNA was hardly affected by salinity, whereas the initial slow increase of m-RNA levels in the early night phase was almost absent in salinized plants. This is considered as one reason for the low NR activity of salinized plants in the first half of the day. It is also suggested that nitrate is a major signal affecting NR expression and activity under salinity. Sugars and amino acids appeared less important.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1365-3040.2000.00568.x

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5

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Nitrate reductase in higher plants: A case study for transduction of environmental stimuli into control of catalytic activity (1999)

Kaiser, W. M. ; Weiner, H. ; Huber, S. C.

Copenhagen : Munksgaard International Publishers

Physiologia plantarum 105 (1999), S. 0

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ISSN: 1399-3054

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: In higher plants, cytosolic NAD(P)H-nitrate reductase (NR) is rapidly modulated by environmental conditions such as light, CO2, or oxygen availability. In leaves, NR is activated by photosynthesis, reaching an activation state of 60–80%. In the dark, or after stomatal closure, leaf NR is inactivated down to 20 or 40% of its maximum activity. In roots, hypoxia or anoxia activate NR, whereas high oxygen supply inactivates NR. Spinach leaf NR is inactivated by phosphorylation of serine 543 and subsequent Mg2+-dependent binding of 14-3-3 proteins at, or close to, this phosphorylation site. At least three different protein kinases (NR-PK) have been identified in spinach leaves that are able to phosphorylate NR on serine 543. Two of them show up as calmodulin-like domain protein kinases (CDPKs), and one as a SNF1-like protein kinase. Dephosphorylation of serine 543 is catalyzed by a Mg2+-dependent protein phosphatase and by a type 2A protein phosphatase (NR-PP), which is regulated by a trimer/dimer interconversion. The NR-PKs, NR-PPs, and 14-3-3s are present even in NR-depleted plant tissues. Artificial activation of NR in vivo is achieved by cellular acidification, by respiratory inhibitors, or by mannose feeding. As for anoxia, these treatments seem to act, at least in part, via cytosolic acidification, mediated by low cytosolic ATP levels. Activation is also achieved by ionophore-induced release of divalent cations from the cytosol. In addition, cytosolic AMP and phosphate esters seem to regulate NR-PK and NR-PP activities, thereby adapting NR activity within minutes to the changing environment.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1034/j.1399-3054.1999.105225.x

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6

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Ultrasound Bone Densitometry of the Os Calcis in Children and Adolescents (2000)

Wünsche, K. ; Wünsche, B. ; Fähnrich, H. ; [et al.]

Springer

Calcified tissue international 67 (2000), S. 349-355

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ISSN: 1432-0827

Keywords: Key words: Ultrasound bone densitometry — Children — Sex — Weight — Height

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Abstract. The aim of the present investigation was to evaluate reference data and to examine whether there were weight-, height-, age-, and sex-related differences of the quantitative ultrasound bone parameters for healthy children and adolescents. A total of 3299 healthy Caucasian children and teenagers (1623 girls and 1676 boys), age range from 6–18 years (mean age 11.4 ± 3.4 years for boys and mean age 11.5 ± 3.3 years for girls) were examined by quantitative ultrasound densitometry (QUS) using the bone sonometer SAHARA (Hologic Inc., Waltham, MA, USA), a waterless, dry system. The parameters broadband ultrasound attenuation (BUA) [dB/MHz] and speed of sound (SOS) [m/second] were evaluated on the right heel in relation to age, sex, weight, and height. There is no correlation between the ultrasound bone parameter SOS and age, height, and weight. BUA increases with age, height, and weight. Significant differences in SOS and BUA between girls and boys were found to probably be caused by the different onset of growth phases and the onset of puberty. SOS and BUA are influenced by changes of bone mineral density. But BUA is dependent on bone size, too. In conclusion, ultrasound bone densitometry is a useful measuring method showing the physiological bone development in childhood and adolescence. The presented results can be used as reference data. Further studies in children with disorders influencing bone metabolism will show in what way various patterns of osteopenia in childhood can be detected.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002230001143

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7

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Allelic variation at a hypervariable compound microsatellite locus in the ascomycete Ascochyta rabiei (1997)

Geistlinger, J. ; Weising, K. ; Kaiser, W. J. ; [et al.]

Springer

Molecular genetics and genomics 256 (1997), S. 298-305

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ISSN: 1617-4623

Keywords: Key words Locus-specific microsatellite analysis ; Microsatellite-primed PCR ; RFLP analysis ; Mutagenesis ; Phytopathogenic fungi

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The genome of the fungal chickpea pathogen Ascochyta rabiei was screened for polymorphisms by microsatellite-primed PCR. While ethidium-bromide staining of electrophoretically separated amplification products showed only limited polymorphism among 24 Tunisian A. rabiei isolates, Southern hybridization of purified PCR fragments to restriction digests of fungal DNA revealed polymorphic DNA fingerprints. One particular probe that gave rise to a hypervariable single-locus hybridization signal was cloned from the Syrian isolate AA6 and sequenced. It contained a large compound microsatellite harbouring the penta- and decameric repeat units (CATTT)n, (CATTA)n, (CATATCATTT)n and (TATTT)n. We call this locus ArMS1 (Ascochyta rabiei microsatellite 1). Unique flanking sequences were used to design primer pairs for locus- specific microsatellite amplification and direct sequencing of additional ArMS1 alleles from Tunisian and Pakistani isolates. A high level of sequence variation was observed, suggesting that multiple mutational mechanisms have contributed to polymorphism. Hybridization and PCR analyses were performed on the parents and 62 monoascosporic F1 progeny derived from a cross between two different mating types of the fungus. Progeny alleles could be traced back to the parents, with one notable exception, where a longer than expected fragment was observed. Direct sequencing of this new length allele revealed an alteration in the copy number of the TATTT repeat [(TATTT)53 to (TATTT)65], while the remainder of the sequence was unchanged.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004380050573

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