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  • Springer  (118)
  • American Association for the Advancement of Science (AAAS)  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Expression of the Xenopus GTP-binding protein gene Ran during embryogenesis (2000)
    Springer
    Development genes and evolution 210 (2000), S. 325-327 
    Details
    ISSN: 1432-041X
    Keywords: Key words Xenopus ; Ran ; Small GTP-binding protein ; Embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The Ran gene family encodes small GTP binding proteins that are associated with a variety of nuclear processes. We isolated a Xenopus Ran cDNA and analyzed the pattern of expression of this gene during embryogenesis. Ran is expressed maternally and later in the CNS, neural crest, mesenchyme, eyes, and otic vesicles. However, expression is not detected in the somites or the notochord.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050320
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  • 2
    Electronic Resource
    Electronic Resource
    Distortion Component Analysis of Outer Hair Cell Motility-Related Gating Charge (1999)
    Springer
    The journal of membrane biology 169 (1999), S. 199-207 
    Details
    ISSN: 1432-1424
    Keywords: Key Words: Outer hair cell — Distortion — Gating charge — Membrane capacitance — Turgor pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract. The underlying Boltzmann characteristics of motility-related gating currents of the outer hair cell (OHC) are predicted to generate distortion components in response to sinusoidal transmembrane voltages. We studied this distortion since it reflects the mechanical activity of the cell that may contribute to peripheral auditory system distortion. Distortion components in the OHC electrical response were analyzed using the whole-cell voltage clamp technique, under conditions where ionic conductances were blocked. Single or double-sinusoidal transmembrane voltage stimulation was delivered at various holding voltages, and distortion components of the current responses were detected by Fourier analysis. Current response magnitude and phase of each distortion component as a function of membrane potential were compared with characteristics of the voltage-dependent capacitance, obtained by voltage stair-step transient analysis or dual-frequency admittance analysis. The sum distortion was most prominent among the distortion components at all holding voltages. Notches in the sum (f1+f2), difference (f2−f1) and second harmonic (2f) components occur at the voltage where peak voltage-dependent capacitance resides (V pkCm ). Rapid phase reversals also occurred at V pkCm , but phase remained fairly stable at more depolarized and hyperpolarized potentials. Thus, it is possible to extract Boltzmann parameters of the motility-related charge movement from these distortion components. In fact, we have developed a technique to follow changes in the voltage dependence of OHC motility and charge movement by tracking the voltage at phase reversal of the f2−f1 product. When intracellular turgor pressure was changed, V pkCm and distortion notch voltages shifted in the same direction. These data have important implications for understanding cochlear nonlinearity, and more generally, indicate the usefulness of distortion analysis to study displacement currents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002329900531
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of optically active ethyl 4-chloro-3-hydroxybutanoate by microbial reduction (1999)
    Springer
    Applied microbiology and biotechnology 51 (1999), S. 847-851 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  A total of 400 yeast strains were examined for the ability to reduce ethyl 4-chloroacetoacetate (COBE) to ethyl 4-chloro-3-hydroxybutyrate (CHBE) by using acetone-dried cells in the presence of a coenzyme-recycling system in water/n-butyl acetate. We discovered some yeast strains that reduced COBE to (S)-CHBE. Heating of acetone-dried cells of the selected yeast strains increased the optical purity of the product. There may be several enzymes that can reduce COBE stereoselectively in the same yeast cells. The cultured broth of Candida magnoliae accumulated 90 g/l (S)-CHBE (96.6% enantiomeric excess, e.e.) in the presence of glucose, NADP and glucose dehydrogenase in n-butyl acetate. When these cells were heated, the stereoselectivity of the reduction increased to 99% e.e. (S)-CHBE is one of the useful chiral building blocks applicable to the synthesis of some pharmaceuticals. We expect that the cheap and industrial production of this important chiral compound will follow the discovery of this yeast strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530051472
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of carvedilol on serum lipids in hypertensive and normotensive subjects (1990)
    Springer
    European journal of clinical pharmacology 38 (1990), S. S139 
    Details
    ISSN: 1432-1041
    Keywords: carvedilol ; serum lipid metabolism ; hypertension ; normotension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of carvedilol (an α · β-blocker) on lipid metabolism were assessed in addition to its hypotensive effect. The subjects were 18 men and 18 women, 20 with hypertension and 16 normotensives with other conditions requiring carvedilol treatment. They were aged from 31 to 79 years and were given a daily dose of 5–20 mg carvedilol (average, 9.7 mg/day) for 12 weeks. Significant falls were seen in blood pressure and heart rate after 12 weeks in the hypertensive subjects (mean ± SE) (systolic: from 164 ± 2 to 141 ± 2 mm Hg,P 〈 0.001; diastolic: from 98 ± 1 to 85 ± 2 mm Hg,P 〈 0.001; heart rate: from 71 to 65 beats/min,P 〈 0.001). Smaller changes in blood pressure and heart rate were seen in the normotensive subjects, with the fall in systolic pressure being significant (from 143±3 to 135 ± 2 mm Hg,P 〈 0.01). There were no significant changes in the overall serum total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and phospholipid levels. In the subgroup with a pretreatment serum triglyceride level of 〉 150 mg/dl, a significant fall of 52.1 mg/dl was seen (P 〈 0.05). Lipoprotein analysis showed a significant fall in α-lipoprotein levels (P 〈 0.05). The atherogenic index did not change significantly, and it was concluded that carvedilol was an effective antihypertensive agent that produced no adverse effects and possibly had beneficial effects on lipid metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01409484
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  • 5
    Electronic Resource
    Electronic Resource
    The analytical method for three-dimensional elastic problems in finite deformations (1989)
    Springer
    Acta mechanica solida Sinica 2 (1989), S. 221-233 
    Details
    ISSN: 0894-9166
    Keywords: compressible materials incompressible materials ; perturbation method ; finite deformations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The three-dimensional elastic problems in finite deformations are not known to have been analyzed by the usual stress function and displacement function. By applying Hasegava's presentation and Adkins perturbation method, we propose a new analytical method for three-dimensional elastic problems for compressible materials and incompressible materials, using the displacement function for axisymmetrical elastic problems in finite deformations with surface force or body force. Further, this analytical method is examined by two simple examples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02207174
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  • 6
    Electronic Resource
    Electronic Resource
    Optical-absorption spectra of ferromagnetic semiconducting HgCr2Se4 thin films (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 1944-1949 
    Details
    ISSN: 0392-6737
    Keywords: Studies of specific magnetic materials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si sono fatte misurazioni degli spettri di assorbimento di film sottili di HgCr2Se4 da 295 K a 25 K nell'intervallo di energia fotonica da 0.5 eV a 2.5 eV. Appare evidente che esiste un'ampia banda di assorbimento con un massimo a circa 0.93 eV a 295 K. Questa banda di assorbimento mostra uno spostamento nel rosso con la diminuzione della temperatura in corrispondenza della transizione dalla banda di valenza alla stretta banda di conduzione. Inoltre si trova che esistono altre transizioni con gap di energia di 1.20, 1.47 e 1.90 eV a 295 K. Come risultato di questa ricerca, si evidenzia la possibilità di costruire laser accordabili da questo materiale.
    Abstract: Резюме Проведены измерения спектров поглощения для тонких пленок HgCr2Se4 в области температур от 295 до 25 К с жнергией фотонов от 0.5 до 2.5 зВ. Показано, что существует сирокая полоса поглощения с максимумом вблизи 0.93 зВ при 295 К. Жта полоса поглощения обнаруживает явление красного смещения с уменьшением температуры, соответсвующей переходу из валентной зоны в узкую зону проводимости. Кроме того, мы обнаружили, что существуют другие переходы 1.20, 1.47, и 1.90 зВ при 295 К. На основе проведенного исследования мы указываем на возможность создания перестраиваемых лазеров на жтом материале.
    Notes: Summary Measurements of the absorption spectra for thin films of HgCr2Se4 were made from 295 K to 25 K in the photon energy range from 0.5 eV to 2.5 eV. It becomes evident that there exists a broad absorption band with a maximum at about 0.93 eV at 295 K. This absorption band shows a red-shift phenomenon with decreasing temperature corresponding to the transition from the valence band to the narrow conduction band. Furthermore, we find out that there exist other transitions with energy gaps of 1.20, 1.47 and 1.90 eV at 295 K. As a result of this investigation we point out the possibility of making tunable lases from this material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02457892
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  • 7
    Electronic Resource
    Electronic Resource
    Preparation of ferromagnetic semiconducting HgCr2Se4 thin films by molecular-beam deposition (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 1798-1802 
    Details
    ISSN: 0392-6737
    Keywords: Studies of specific magnetic materials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Film policristallini sottili di semiconduttore HgCr2Se4 sono stati preparati per la prima volta su substrati isolanti di cristalli singoli MgAl2O4 mediante deposizione a raggi molecolari e successiva tempra con HgSe. Si sono ottenute le condizioni ottimali per preparare film sottili a fase singola di HgCr2Se4. La resistenza magnetica e gli effetti di Hall di questi film sono stati misurati da 77 a 295 K in campi magnetici fino a 1.19·106 A/m. Diventa evidente che queste proprietà elettriche dei film sono influenzate da strati di interdiffusione nei film vicino ai substrati o dagli strati in disordine magnetico come i bordi amorfo o del grano in film.
    Abstract: Резюме Впервые приготовлены поликристаллические тонкие пленки ферромагнитных полупроводников HgCr2Se на непроводящих монокристаллических подложках MgAl2O4 с помощью осаждения молекулярного пучка и последующего отжига с HgSe. Определяются оптимальные условия для приготовления тонких пленок HgCr2Se4, имеющих единственную фазу. Измеряются, магниторезистивный эффект и эффект Холла для этих пленок в области температур от 77 до 295 К и при магнитных полях вплоть до 1.19·106 А/м. Отмечается, что на электрические свойства этих пленок влияют слои в пленках вблизи подложки или магнитноразупорядоченные слои, такие как аморфные или зернистые границы в пленках.
    Notes: Summary Polycrystalline thin films of the ferromagnetic semiconductor HgCr2Se4 have been prepared for the first time on insulating MgAl2O4 single-crystal substrates by molecular-beam deposition and subsequent annealing with HgSe. The optimum conditions for preparing single-phase thin films of HgCr2Se4 were obtained. The magnetoresistance and Hall effects of these films were measured from 77 to 295 K in magnetic fields up to 1.19·106 A/m. It becomes evident that these electrical properties of the films are affected by the interdiffusion layers in the films near the substrates or the magnetically disordered layers such as amorphous or grain boundaries in the films.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02457868
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  • 8
    Electronic Resource
    Electronic Resource
    Surface flaws in ZrF4-based fluoride optical fibres with improved tensile strength (1987)
    Springer
    Journal of materials science 6 (1987), S. 1440-1442 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01689315
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  • 9
    Electronic Resource
    Electronic Resource
    Preparation and properties of cyclodextrin inclusion compounds of organometallic complexes. Ferrocene inclusion compounds (1984)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 2 (1984), S. 791-798 
    Details
    ISSN: 1573-1111
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Inclusion compounds of ferrocene(FcH) and its derivatives with cyclodextrins(CDs; α-CD, β-CD, and γ-CD) were prepared. CD-ferrocene inclusion compounds were obtained in a crystalline state in high yield. β-CD and γ-CD formed 1∶1 stoichiometric inclusion compounds with ferrocene and its derivatives. α-CD formed 2∶1 (CD:guest) complexes with ferrocene and the monosubstituted derivatives, but did not form complexes with 1,1′-disubstituted derivatives, α-CD-FcH and β-CD-FcH complexes are thermally stable and do not liberate ferrocene on heating at 100°C in vacuo. The cyclodextrin inclusion compounds were characterized by1H-NMR, IR, UV, and CD spectra. A large positive induced Cotton effect was observed in the case of β-CD-FcH complex, while the γ-CD-FcH complex showed a negative spectrum. The binding mode is discussed. β-Cyclodextrin was found to form inclusion complexes in ethylene glycol, diethylene glycol, triethylene glycol, methyl cellosolve, ethyl cellosolve, methyl alcohol, and glycerine solutions. γ-CD also formed complexes in ethylene glycol solution. The binding of ferrocene by β-CD is stronger in ethylene glycol than in dimethyl sulfoxide and dimethyl formamide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00662247
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  • 10
    Electronic Resource
    Electronic Resource
    Cloning of the gene encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase from terpenoid antibiotic-producing Streptomyces strains (2000)
    Springer
    Molecular genetics and genomics 262 (2000), S. 957-964 
    Details
    ISSN: 1617-4623
    Keywords: Key words Mevalonate pathway ; HMG-CoA reductase ; Prokaryote ; Streptomyces ; Terpentecin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated a mutant lacking 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase activity from a terpenoid antibiotic (terpentecin) producer, Streptomyces griseolosporeus MF730-N6, which uses both the mevalonate and nonmevalonate pathways for the formation of isopentenyl diphosphate, by screening terpentecin non-producing mutants. Terpentecin is known to be synthesized via the mevalonate pathway. The gene encoding HMG-CoA reductase (hmgg) was cloned and identified by complementation of the mutant, using a self-cloning system developed in this study for strain MF730-N6. The corresponding hmgs gene for HMG-CoA reductase was also cloned from Streptomyces sp. KO-3988, which produces the terpenoid antibiotic furaquinocin. Sequence analysis of hmgg and hmgs showed that both genes encode polypeptides of 353 amino acids which are 84% identical to each other. A search of protein sequence databases revealed that both gene products were also similar to HMG-CoA reductases from a variety of other organisms, including Streptomyces sp. CL190 (hmgg is 89% and hmgs 85% identical to its CL190 homolog), sea urchin (40.3 and 40.5%), German cockroach (37.6 and 38.4%), and Camptotheca acuminata (39.7 and 40.8%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00008664
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