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  • Wiley-Blackwell  (16)
  • De Gruyter
  • 2000-2004  (3)
  • 1990-1994  (21)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 44 (1992), S. 277-290 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We compare three global configuration search methods on a scalable model problem to measure relative performance over a range of molecule sizes. Our model problem is a 2-D polymer composed of atoms connected by rigid rods in which all pairs of atoms interact via Lennard-Jones potentials. The global minimum energy can be calculated analytically. The search methods are all hybrids combining a global sampling algorithm with a local refinement technique. The sampling methods are simulated annealing (SA), genetic algorithms (GA), and random search. Each of these uses a conjugate gradient (CG) routine to perform the local refinement. Both GA and SA perform progressively better relative to random search as the molecule size increases. We also test two other local refinement techniques in addition to CG, coupled to random search as the global method. These are simplex followed by CG and simplex followed by block-truncated Newton. For small problems, the addition of the intermediate simplex step improved the performance of the overall hybrid method. © 1992 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 33-45 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Autogeneic bone marrow was implanted into an artificially created cavity in a segment of rat sciatic nerve, after removal of nerve fascicles, without damaging the epineurium or surrounding microcirculation. Under these conditions, the bone marrow induces capillary growth and forms granulation tissue from surrounding tissues, the behavior of pericytes being studied in the preformed (preexisting) postcapillary venules of the latter. Beginning 20 h after bone marrow implantation, the pericytes of the preexisting postcapillary venules hypertrophy, with shortening of their processes, prominent nucleoli, dispersal of ribosomes into their free form, fragmentation of basal lamina, and increased DNA synthesis. The number of contact surfaces between pericytes and endothelium is noticeably lower than in controls. Many pericytes are in mitosis. Cells with a shape transitional between pericytes and interstitial fibroblast-like cells appear. In some cases, Monastral Blue (MB) was used as a marker of the cells in preexisting venule walls of the graft bed. In the earlier stages of the experiment, the MB labelling is restricted to the cytoplasm of pericytes and endothelial cells of postcapillary venules, and to the macrophages that occur in the space between pericytes and endothelium. Furthermore, the marker continues to be observed, at a later stage, in some of the following cells: pericytes and endothelial cells of the newly formed vessels, macrophages migrating into the interstitium, transitional cells between pericytes and fibroblasts, and typical fibroblasts of the granulation tissue. The present study provides greater evidence that preformed microvasculature pericytes are substantially activated during postnatal angiogenesis and granulation tissue formation, suggesting that they may contribute to the origin of new pericytes and fibroblasts. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 35 (1990), S. 802-808 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model was developed and tested to simulate the generation and transfer of heat in solid substrate fermentation (SSF). The experimental studies were realized in a 1-L static bioreactor packed with cassava wet meal and inoculated with Aspergillus niger. A simplified pseudohomogeneous monodimensional dynamic model was used for the energy balance. Kinetic equations taking into account biomass formation (logistic), sugar consumption (with maintenance), and carbon dioxide formation were used. Model verification was achieved by comparison of calculated and experimental temperatures. Heat transfer was evaluated by the estimation of Biot and Peclet heat dimensionless numbers 5-10 and 2550-2750, respectively. It was shown that conduction through the fermentation fixed bed was the main heat transfer resistance. This model intends to reach a better understanding of transport phenomena in SSF, a fact which could be used to evaluate various alternatives for temperature control of SSF, i.e., changing air flow rates and increasing water content. Dimensionless numbers could be used as scale-up criteria of large fermentors, since in those ratios are described the operating conditions, geometry, and size of the bioreactor. It could lead to improved solid reactor systems. The model can be used as a basis for automatic control of SSF for the production of valuable metabolites in static fermentors.
    Additional Material: 8 Ill.
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  • 4
    ISSN: 0899-0042
    Keywords: NSAIDs ; enantioselectivity ; prostaglandin E2 ; thromboxane B2 ; HUVEC ; PMN ; keratinocytes ; P388D1 ; platelets ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pharmacological activity of rac-ketoprofen and its enantiomers was investigated in vitro using different cellular models. The effect of these compounds on arachidonic acid metabolism was assessed by measuring the inhibition of prostanoid generation under the action of several agonists. Thus, we have evaluated the inhibition of (1) thromboxane B2 synthesis in rabbit platelets and human polymorphonuclear leukocytes (PMNs), (2) prostaglandin E2 synthesis in three cultured cells, namely human umbilical vein endothelial cells (HUVEC), human keratinocytes, and mouse macrophage-like P388D1 cells. The IC50 values found for (+)-(S)-ketoprofen were in the range between 0.1 nM and 0.8 μM, being slightly lower in all models than those found for rac-ketoprofen (0.4 nM-3 μM). On the other hand, (-)-(R)-ketoprofen showed inhibition of cyclooxygenase only at concentrations two or three orders of magnitude higher than those required for the (+)-(S) enantiomer. These results, obtained with cell types of relevance for inflammatory processes and with compounds of high optical purity, demonstrate that the prostanoid biosynthesis inhibition caused by the drug rac-ketoprofen is exclusively due to its dextrorotatory enantiomer. © 1993 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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  • 5
    ISSN: 1434-193X
    Keywords: Thiadiazolidinones ; Spiro compounds ; Thiazoles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The design, synthesis and evaluation of a series of 1,2,4-thiadiazolidinones with potential muscarinic receptor binding properties has been performed. During the synthesis of the target compounds, we observed an interesting reductive cleavage of the thiadiazolidinone system which leads to the formation of the novel piperidine spiro triazine heterocycle. The synthesis, structural elucidation (NMR spectroscopy and X-ray diffraction) and biological evaluation of the new compounds are described. With the structures unequivocally established, a mechanism for the formation of the spiro compound is proposed.Supporting information for this article is available on the WWW under //http://www.wiley-vch.de/contents/jc_2046/2000/099462_s.pdf or from the author.
    Additional Material: 3 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 338-345 
    ISSN: 1040-452X
    Keywords: Sperm capacitation ; True acrosome reaction ; Oviductal epithelial cell monolayers ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effects of different epithelial cells, namely, hamster oviduct, sheep oviduct, and pig kidney epithelial cells (IBRS-2), on the viability, percentage of progressive motility (PPM), and acrosome reactions of ejaculated ram spermatozoa were investigated. Sperm aliquots were cultured on cells, cell-conditioned medium 199, or control medium 199. The PPM of unattached spermatozoa was estimated after 0, 3, 6, 9, 12, and 24 hr of incubation at 37°C under 5% CO2 in air. Viability and the occurrence of true acrosome reactions were assessed using a triple-stain technique. Spermatozoa started to attach within 1 hr of coculture with the hamster or sheep oviductal epithelial cell (OEC) monolayers, and these spermatozoa showed vigorous tail motion. No spermatozoa were found to attach to the IBRS-2 monolayer. The PPM of unattached spermatozoa cocultured with the various types of epithelial cell monolayers for 12 hr was significantly higher than that of spermatozoa incubated in conditioned media or medium 199 alone (54% in hamster OEC vs. 40% in conditioned; 68% in sheep OEC vs. 38% in conditioned; 36% in control medium). On the other hand, after 24 hr of incubation, there were no differences in the PPM of spermatozoa cocultured with epithelial cells or incubated in conditioned media. The percentages of cells undergoing a true acrosome reaction reached maximum values (P 〈 0.05) in spermatozoa incubated for 9 hr in the presence of hamster OEC (22.5%) or for 12 hr on sheep OEC (20.5%) monolayers. IBRS-2, a commercial nonreproductive cell type, had a positive influence on both PPM and sperm viability but no effect on the occurrence of the acrosome reaction. Interactions leading to the acrosome reaction were thus observed only when spermatozoa were cocultured with OEC monolayers. The values of PPM in unattached sperm cells seen after 12 hr of coculture with OEC or IBRS-2 were still at a high level (52-67%) for in vitro fertilization. The coculture with OECs provides an “in vitro” model to study the capacitation processes in a situation that may resemble that occurring in vivo. Moreover, the coculture with hamster OECs may provide a convenient and standardized in vitro system to study mechanisms underlying capacitation and the acrosome reaction. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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  • 7
    ISSN: 1040-452X
    Keywords: Steroid receptors ; Rabbit endometrium ; Hormone regulation ; Gene expression ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The progesterone receptor (PR) plays a pivotal role in the maturation process of the secretory endometrium, implantation and maintenance of pregnancy in rabbits. To determine the dynamics of PR gene expression and its physiological significance, the endometrial expression of PR and PR mRNA were evaluated and compared with the expression of the progesterone-regulated uteroglobin (UG) gene during 0-5 days post-coitus in rabbits. The results of immunoblot experiments indicated the presence of PR in endometrial cell extracts from days 1-4 of pregnancy with maximum PR immunostaining on day 2, followed by a marked diminution until its complete disappearance on day 5. When endometrial PR mRNA content was assessed by Northern blots, the results were similar to those of PR immunostaining, with maximal concentrations on the second day after mating. However, PR mRNA levels were still high on day 3, despite the concomitant decrease in immunostainable PR. Endometrial UG gene expression, on the other hand, exhibited a different time sequence. Thus, the UG content in uterine flushings progressively increased from day 3 after mating, reaching maximal levels on the fifth day. The endometrial UG mRNA content presented a similar profile, as its maximum concentration occurred on days 4-5. The overall results indicate that endometrial PR is down-regulated at both the mRNA and protein levels, possibly by endogenous progesterone during early pregnancy. The striking observation that maximal expression of endometrial UG gene products occurred when PR and its mRNA are no longer detectable suggests an important role for this progesterone-binding uterine protein during the preimplantation period. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 34-42 
    ISSN: 1059-910X
    Keywords: Intercellular tracer ; Lanthanum ; Testis ; Galea ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: With the purpose of evaluating a new intercellular tracer, nickel-K ferrocyanide, we compared results yielded by lanthanum with information provided by nickel. This was done in the seminiferous epithelium of Holtzman rats of several postnatal ages and in a wild local seasonal breeder Galea musteloides. Tissues were studied with transmission electron microscopy and freezefracture replications. Nickel tracing proved to delineate cell contours more intensely and less interruptedly than lanthanum. With regard to seasonal variations in adult galea, the limits of the barrier were similar to those described in other mammals: spermatogonia, preleptotene, and leptotene spermatocytes were surrounded by the tracer in the basal compartment. The zygotenepachytenes were contained in the lumenal compartment and tracers were stopped at the inter - Sertoli cell tight junctions. During the inactive spermatogenic phase in winter, the seminiferous epithelium contained Sertoli cells and occasional germ cells, never beyond the spermatocyte stage. The tracer filled intercellular spaces, indicating that the barrier was incompetent. Some resting germ cells showed nuclear hyperchromasia, karyolysis, organelle loss, cell shrinkage, and cell fusion leading to a multinucleated cells. The inter-Sertoli tight junctions were scanty and had randomly oriented and discontinuous junctional strands. Moreover, inter - Sertoli cell gap junctions proliferated. During the active spermatogenic phase in summer, junctions were numerous. Their junctional strands were parallel to each other, and continuous.
    Additional Material: 18 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 336 (1994), S. 243-246 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dye-sensitized singlet molecular oxygen-mediated photo-oxidation of a series of substituted model compounds for phenolic-type pesticides was studied in several solvents in the alkaline range. From a kinetic point of view, the feasibility to regulate the environmental photo-oxidative degradation by means of the incorporation of electron- withdrawing or electron-releasing substituents in the phenolic nucleous was demonstrated.The photo-oxidability varies from relatively high quantum yields values (0.11 in the most favourable cases for 2,6-dimethyl-4-bromophenol in organic solvent) to non-reactivity (for highly deactivated compounds such as 2,4-dinitrophenol).
    Additional Material: 3 Ill.
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  • 10
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of eight new substituted 2-(p-R2-phenyl)-indole-3-carboxyaldehydes which have potentially useful pharmacological properties, are presented.
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