bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased metal bioavailability following alteration of freshwater dissolved organic carbon by ultraviolet B radiation exposure
Authors: Winch Susan , Ridal Jeffrey , Lean David 
Published: October 2002

AbstractDissolved organic carbon (DOC) is critically important in the chemistry of freshwater. It complexes heavy metals, making them less bioavailable to aquatic organisms, and absorbs and attenuates UVB radiation, undergoing degradation and alteration in the process. This study examined changes in metal toxicity to the freshwater green alga Pseudokirchneriella subcapitata in high‐ and low‐DOC natural water samples after exposure to UVB radiation. Brown‐water and clear‐water samples were irradiated for 0, 5, and 10 days. The DOC concentrations of the samples were measured, and they were subsequently spiked with Cu, Ni, Zn, Cd, Co, and Pb and used in algal bioassays to measure changes in metal toxicity following irradiation. DOC concentrations declined only 20% with UVB irradiation in both samples, although DOC concentration was much higher in the brown‐water sample than in the clear‐water sample. In the brown‐water sample metal toxicity increased up to 78% after 10 days of UVB irradiation for Cu, Zn, Co and Pb, but not for Ni and Cd. Changes were less evident in the clear‐water sample. The differences observed between IC50 values for relatively fresh, high‐DOC water from the headwaters of the Raisin River and much “older,” low‐DOC water from Lake Simcoe point to the likelihood of the effects observed in this study being many times greater in the natural environment because of very long exposure to solar radiation. Alteration of DOC by UVB irradiation may influence primary productivity and species composition, especially in waters in which metal concentrations are high. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 267–274, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10057
Validation of the AeroDyn subroutines using NREL unsteady aerodynamics experiment data
Authors: Laino David J. , Hansen A. Craig , Minnema Jeff E. 
Published: October 2002

AbstractCompletion of the full‐scale wind tunnel tests of the NREL Unsteady Aerodynamics Experiment (UAE) phase VI allowed validation of the AeroDyn wind turbine aerodynamics software to commence. Detailed knowledge of the inflow to the UAE was the bane of prior attempts to accomplish any in‐depth validation in the past. The wind tunnel tests permitted unprecedented control and measurement of inflow to the UAE rotor. The data collected from these UAE tests are currently under investigation as part of an effort to better understand wind turbine rotor aerodynamics in order to improve aeroelastic modelling techniques. Preliminary results from this study using the AeroDyn subroutines are presented, pointing to several avenues towards improvement. Test data indicate that rotational effects cause more static stall delay over a larger portion of the blades than predicted by current methods. Despite the relatively stiff properties of the UAE, vibration modes appear to influence the aerodynamic forces and system loads. AeroDyn adequately predicts dynamic stall hysteresis loops when appropriate steady, 2D aerofoil tables are used. Problems encountered include uncertainties in converting measured inflow angle to angle of attack for the UAE phase VI. Future work is proposed to address this angle‐of‐attack problem and to analyse a slightly more complex dynamics model that incorporates some of the structural vibration modes evident in the test data. Copyright © 2002 John Wiley & Sons, Ltd.
Expanding wake induction effects on thrust distribution on a rotor disc
Authors: Chaney K. , Eggers A. J. 
Published: October 2002

AbstractWake expansion is necessary to satisfy conservation of mass when induction in flow through a wind turbine rotor disc is substantial. An iterative model is developed to calculate this expansion in an axisymmetric wake generated by an idealized unyawed disc operating at high tip speed ratios. The model satisfies all conservation constraints and boundary conditions and predicts induction in the wake flow normal to the rotor disc plane due to the sheet of vorticity convected downwind along the surface of the wake. Expansion effects on induction in flow through the rotor disc and in the wake are noted. The effect of skewing the axis of the wake out of alignment with the axis of a yawed rotor disc is approximated with a simple crossflow model which yields an expanding skewed wake. The sheet of vorticity convected downwind along the surface of this wake is found to significantly alter the induction in flow through the rotor disc from that predicted when wake expansion is neglected with the cylindrical wake approximation. This alteration is in the direction of levelizing the induction and resulting thrust distributions on the yawed disc. This in turn reduces the forward shift of the centre of thrust from the axis of a yawed rotor, and this reduction may be very substantial at higher levels of induction and hence wake expansion. The effects of wake expansion on the level of thrust appear to be of second order compared with the effects on centre of thrust. These findings are likely to be of particular importance to small wind turbines which are designed to yaw out of the wind as required at higher wind speeds to prevent undesirable overshoots in power and loads. Copyright © 2002 John Wiley & Sons, Ltd.
Time dependence characterization of Pb and Br concentrations in samples from ombrotrophic peat bogs in Austria and Poland by energy‐dispersive x‐ray fluorescence spectrometry
Authors: Hołyńska B. , Ostachowicz J. , Samek L. , Streli C. , Wachniew P. , Wobrauschek P. 
Published: October 2002

AbstractIt long has been known that ombrotrophic peat bog preserves the record of the atmospheric deposition of metal pollutants. In this paper, the results of an investigation of two peat cores taken in Austria from Langmoos bog located near a motorway and one taken in southern Poland located far away from main roads are presented. The concentration levels of Pb and Br in dated peat cores were studied in order to find out whether the close location of a motorway to a bog will influence the contents of these elements in peat. Copyright © 2002 John Wiley & Sons, Ltd.
Angular dependence of L x‐ray production cross‐section in seven elements from Au to U at 59.5 keV photon energy
Authors: Seven Sabriye , Koçak Kadir 
Published: October 2002

AbstractThe Ll, Lα, Lβ and Lγ x‐ray production cross‐sections in U, Th, Bi, Pb, Tl, Hg and Au were measured using 59.5 keV incident photon energies in the angular range 40–130°. The measurements were performed using the 241Am radioisotope as photon source and a detection system with an Si(Li) detector. Although differential cross‐sections for Lβ and Lγ x‐rays were found to be angle independent, within experimental error, those for Ll and Lα x‐rays were found to be angle dependent. This confirms the angular dependence of measured photon induced Ll and Lα x‐ray production cross‐sections as reported by two groups. Further, the present results also confirm the theoretical predictions of two other groups but are contrary to the results reported by others. Integral cross‐sections for production of Ll, Lα, Lβ and Lγ x‐rays were also deduced and were found to be in good agreement with the theoretical values. Copyright © 2002 John Wiley & Sons, Ltd.
Ensuring quality and sustainability in after‐school programs
Authors: Chung An‐Me , de Kanter Adriana A. , Stonehill Robert M. 
Published: October 2002

AbstractThe Charles Stewart Mott Foundation and the U.S. Department of Education are engaged in a unique public‐private partnership that strives to integrate the assets and flexibility of philanthropy with the breadth of a major federal program to support meaningful after‐school programs and school‐community partnerships for children, youth, families, and communities.
Reproductive endocrine responses to photoperiod and exogenous gonadotropins in the pallas' cat (Otocolobus manul)
Authors: Brown Janine L. , Graham Laura H. , Wu Julie M. , Collins Darin , Swanson William F. 
Published: October 2002

AbstractFecal samples were collected for 14–26 months from three male and six female Pallas' cats (Otocolobus manul) to examine gonadal steroidogenic activity in response to changes in photoperiod and treatment with exogenous gonadotropins. Females exhibited a seasonal anestrus from May–December, excreting consistently low concentrations of fecal estrogens (overall mean, 50.2±8.5 ng/g). During the breeding season (January–April), baseline fecal estrogen concentrations were higher, averaging 128.4±18.9 ng/g, with peak concentrations ranging from 455.8–909.6 ng/g. Interpeak intervals in estrogen excretion ranged between 7 and 21 days, with an average estrous cycle length of 14.3±1.7 days. Two females became pregnant after natural mating, with overall luteal progestogen concentrations averaging ∼40 μg/g throughout gestation. Fecal estrogens increased in mid‐gestation, peaking just before birth. Induction of follicular development with eCG (100–300 IU, i.m.) resulted in an increase in fecal estrogens (peak range, 263.1–1198.1 ng/g), followed by a postovulatory increase in fecal progestogens (overall mean, 41.1±11.9 μg/g) after hCG (75–150 IU, i.m.). Despite apparently normal ovarian responses, none of the females conceived after artificial insemination (AI). The gonadotropin‐induced nonpregnant luteal phase lasted 49.8±5.3 days (range, 30–60 days), whereas gestation lasted ∼70 days. In the male Pallas' cat, fecal androgens were elevated from November–April (overall mean, 352.3±30.3 ng/g) compared with nadir concentrations during the rest of the year (82.1±3.3 ng/g). Entrainment of seasonality to photoperiod was demonstrated by stimulation of gonadal steroidogenic activity in cats exposed to increasing artificial light during natural (nonbreeding season) and artificially induced short‐day photoperiods. In summary, reproduction in Pallas' cats is highly seasonal and photoperiod‐dependent. Females exhibit elevated baseline and peak fecal estrogen concentrations for 3–4 months during late winter/early spring. Testicular steroidogenic activity precedes the rise in female estrogen excretion by about 2 months, presumably to ensure maximal sperm production during the breeding season. Zoo Biol 21:347–364, 2002. Published 2002 Wiley‐Liss, Inc.
Veterinary concerns of captive duikers
Authors: Willette Michelle M. , Norton Terry L. , Miller Christine L. , Lamm Marnie G. 
Published: October 2002

AbstractIn March 2000, professionals from various duiker‐holding institutions conducted a workshop at the Wildlife Conservation Society’s Wildlife Survival Center (WCS/WSC) on St. Catherine’s Island entitled Husbandry, Nutrition, and Health of Captive Duikers. The product of this workshop was a suite of monographs, one of which dealt with veterinary issues and took the form of a series of veterinary guidelines. These guidelines are based on the general disease and management concerns of neonatal and adult duikers, and include: 1) preventive medicine recommendations with preshipment, quarantine, and routine physical examination protocols; 2) restraint and anesthesia recommendations; 3) a necropsy protocol; and 4) a summary of medical informational needs. The main intent of these protocols is to outline minimum standards of veterinary care and inquiry for duiker species in captivity. Eventually, this will result in the establishment of a consistent and comprehensive data base, from which future individuals will greatly benefit in the form of improved husbandry, nutrition, and medicine. Zoo Biol 21:197–207, 2002. © 2002 Wiley‐Liss, Inc.
Rayleigh‐Bénard convection as a tool for studying dust devils
Authors: Fiedler Brian H. , Kanak Katharine M. 
Published: October 2002

AbstractIntense columnar vortices in a convecting layer are explored with direct numerical simulations that are otherwise similar to the large‐eddy simulations of6, Q. J. R. Meteorol. Soc. 126, 2789–2810). With free‐slip boundaries and a Rayleigh number of 106(4096 times critical), vortices similar to large dust devils are readily produced. The genesis, intensity and life cycle of these intense vortices (dust devils) are studied. The simulated dust devils last for the order of the over‐turning time of the largest eddies. The intensity is limited by the hydrostatic pressure drop supported by the buoyancy confined in the core. The genesis of a simulated dust devil requires not only tilting of the baroclinically generated vorticity, but also a symmetry‐breaking event that allows one sign of vorticity to become concentrated in an updraft. Such symmetry breaking is the rule with random initialization in the simulations. However, when initialization is restricted to certain Fourier modes, exceptions are found that produce only symmetric vortex couplets that are relatively weak. Copyright © 2001 Royal Meteorological Society.
Failure of sister chromatid separation leads to formation of diplochromosomes in colcemid treated PtK1 cells
Authors: Ghosh Sibdas , Paweletz Neidhard , Schroeter Dieter 
Published: October 2002

AbstractThe origin of diplochromosomes has been traced in multinucleate rat kangaroo cells (PtK1) obtained after colcemid treatment. In these cells the diplochromosomes were shown to originate from restitution nuclei, indicating that they were formed due to the omission or failure of sister chromatid separation and not due to endoreduplication. In this context the mechanism of sister chromatid separation has been discussed. The independence of this mitotic event from other associated processes, such as chromosome condensation, nuclear envelope breakdown or spindle formation has been stressed.
Disruption of microtubules induces formation of actin fibrils in density‐inhibited 3T3 cells.
Authors: Kajstura J. , Bereiter‐Hahn J. 
Published: October 2002

AbstractIn density‐inhibited 3T3 fibroblast cultures F‐actin is localized almost exclusively at the cell‐to‐cell borders. Depolymerization of microtubules results in a rearrangement of the F‐actin pattern. Numerous actin bundles are formed, most of them are anchored to the cell borders. This rearrangement is preceded by a transient rise in F‐actin content.
The absence of confronting cisternae following thymidine‐induced synchronization in HeLa cells
Authors: Palisano John R. 
Published: October 2002

AbstractThis is the first report of the elimination of confronting cisternae (CC), prominent organelles in dividing HeLa cells, upon experimental manipulation of the cells. CC are lost when a double thymidine block is employed to synchronize cell division. This observation is consistent with the hypothesis that the occurrence of CC in some fetal cells and in selected tumor cells depends on the speed at which the cells cycle through mitosis. If thymidine blocks DNA synthesis and arrests cells at the G1/S interface, then thymidine probably has an indirect effect on CC. This paper reports the effect of thymidine on the occurrence of CC and briefly discusses how inhibitors of membrane synthesis or microtubule polymerization may affect the occurrence of CC during mitosis.
Insulin rescues the unicellular eukaryote Tetrahymena from dying in a complete, synthetic nutrient medium
Authors: Christensen Søren T. 
Published: October 2002

AbstractThe presence of 10−6 M bovine insulin in chemically defined nutrient medium prevented cell death and improved cell proliferation of the ciliate Tetrahymena pyriformis when inoculated at low initial cell density. The action of insulin was found to be restricted to the 22‐30 fragment of the B‐chain. These results suggest that small peptides are involved in regulation of cell survival and cell proliferation in Tetrahymena pyriformis.
Matrix metalloproteinases and endometrial remodelling.
Authors: Salamonsen Lois A. 
Published: October 2002

AbstractMenstruation, angiogenesis, embryo implantation and placentation are natural processes involving degradation of the extracellular matrix within the endometrium. A number of matrix metalloproteinases (MMPs) and their natural tissue inhibitors (TIMPs) have now been identified in association with these processes. In particular, mRNA for proMMP‐1 and proMMP‐3 and for TIMP‐1 and TIMP‐2 are elevated in human endometrial tissue at menstruation compared with other times of the female reproductive cycle. ProMMPs −1, −2, −3 and −9 are released from cultured human endometrial stromal cells, production of all but proMMP‐2 being regulated by cytokines known to be expressed in human endometrial epithelium. At least two gelatinases are released by ovine trophoblast in culture and can be flushed from the uterine lumen at the time of implantation. Thus, matrix metalloproteinases clearly have roles in normal endometrial functions.
Hormones and neurotransmitters release: four mechanisms of secretion
Authors: Dunant Yves 
Published: October 2002

ABSTRACTDistinct mechanisms operate in different secreting systems, they are 1) free diffusion through the plasma membrane; 2) exocytosis resulting from fusion of a secretory granule with the plasma membrane; 3) fleeting release from a granule through a transient pore without full fusion; 4) release through a specialised plasmalemmal molecule such as the mediatophore. The latter mechanism is proposed to operate in rapid synapses in which the neurotransmitter is emitted as an abrupt chemical impulse of quantal composition. There, release is momentarily signalled in the plasma membrane by large intramembrane particles. Synaptic vesicles are also essential for regulation of this type of release. They fuse with the plasma membrane only late after activity and seem to be involved in calcium sequestration and extrusion.
Benzamide‐induced changes in the actin cytoskeleton in human skin fibroblasts.
Authors: Korohoda W. , Michalik M. , Pierzchalska M. 
Published: October 2002

ABSTRACTThe incubation of human skin fibroblasts in the presence of 10 mM benzamide in Joklik's modification of Eagle's Minimal Essential Medium caused an extensive reorganization of actin filaments. The disappearance of stress fibers and changes in cell morphology were observed, whereas no changes in the microtubule architecture were noticed. The observed effects appeared fully reversible within 3 hours after the removal of benzamide. The results are discussed in relation to the two known activities of benzamide as an anaesthetic and an inhibitor of ADP‐ribosylation.
Glycolipid patterns during xenopus embryo development
Authors: Gornati Rosalba , Rizzo Angela M. , Tong Xiao‐Wei , Berra Bruno , Bernardini Giovanni 
Published: October 2002

ABSTRACTGlycolipid patterns have been studied during the first six days of Xenopus embryo development. Glycolipid contents showed a sharp increase more evident after the third day of development. Glucosylceramide and sulphatide are not only the most represented species, but also those which exhibit a statistically significant percentage change during early development. Among gangliosides, GD3 is the most represented specie. Two polysialylated gangliosides with not yet established structures are also present.
MUSCARINIC ACETYLCHOLINE RECEPTOR SUBTYPE mRNAs IN THE HUMAN AND RAT VESTIBULAR PERIPHERY
Authors: WACKYM PHILLIP A. , CHEN CAROLINE T. , ISHIYAMA AKIRA , PETTIS ROBERT M. , LÓPEZ IVÁN A. , HOFFMAN LARRY 
Published: October 2002

AbstractThe expression of the five muscarinic acetylcholine receptor (mAChR) subtypes (m1–m5) in the vestibular end‐organs and in the primary afferent vestibular ganglia of the human and rat was studied using RT‐PCR from the two tissue populations from both species. In the human, although all five mAChR subtypes were expressed in brain, only the m1, m2, and m5 mAChR subtypes were amplified from both the vestibular ganglia and the vestibular end‐organs, while in the rat, all five mAChR subtypes were expressed. These data suggest that the efferent cholinergic axo‐dendritic and axo‐somatic synapses have a muscarinic component and that there are pharmacologic implications for patients with vestibular dysfunction.
THE EXPRESSION OF ESTROGEN RECEPTOR AND ESTROGEN EFFECT IN MBA‐15 MARROW STROMAL OSTEOBLASTS
Authors: SHAMAY A. , KNOPOV V. , BENAYAHU D. 
Published: October 2002

AbstractMBA‐15, a marrow stromal‐derived cell line, was shown to express an estrogen receptor. This finding was confirmed byin situhybridization and receptor binding assay. An exposure to estrogen (10−12–10−6m) in a dose response manner resulted in a decrease of cell proliferation as measured by MTT assay. Cell function was measured by enzymatic activities of two osteoblastic markers, CD10/NEP and alkaline phosphatase. These enzymatic activities were elevated following the estrogen treatment. This model enabled direct evaluation of the estrogen effect on stromal osteoblast cells.
NUCLEAR FACTOR OF ACTIVATED T CELLS (NFAT) IS A POSSIBLE TARGET FOR DEXAMETHASONE IN THYMOCYTE APOPTOSIS
Authors: WISNIEWSKA MARTA , STANCZYK MAGDALENA , GRZELAKOWSKA‐SZTABERT BARBARA , KAMINSKA BOZENA 
Published: October 2002

Cell death plays a critical role in the generation of an effective immune system. During maturation T lymphocytes are generated, censored and eliminated in the thymus. These events are temporally associated with developmental changes in the levels of transcription factors including NFAT. The NFAT transcription factor (nuclear factor of activated T cells) is implicated in the regulation of T‐lymphocyte proliferation and transcriptional activation of genes encoding lymphokines. It has been demonstrated that discontinuities in the inducibility of NFAT and AP‐1 transcription factors occur during transition of immature thymocytes into cortical thymocytes which are eliminated by apoptosis.To understand the molecular basis of these developmental intrathymic changes, we studied DNA‐binding activities of transcription factors during dexamethasone‐induced apoptosis of immature thymocytes. We observed a specific loss of NFAT DNA‐binding activity after dexamethasone treatment. It correlated with a selective disappearance of one out of two AP‐1 complexes. Our data suggest that NFAT complex is a possible target in dexamethasone‐induced apoptosis.
CELL SURFACE LOCALIZATION OF THE 60 kDa HEAT SHOCK CHAPERONIN PROTEIN (hsp60) IN MAMMALIAN CELLS
Authors: SOLTYS BOHDAN J. , GUPTA RADHEY S. 
Published: October 2002

AbstractTo investigate whether the 60‐kDa heat shock chaperonin protein (hsp60) is present on the surface of mammalian cells, we used immunogold labeling of intact cells and backscattered electron imaging to image gold particles. Chinese hamster ovary cells and the human leukemic CD4‐positive T‐cell line CEM‐SS on glass coverslips were labeled using affinity‐purified monoclonal and polyclonal antibodies specific for hsp60 and 30 nm gold markers. Cells were imaged using the scanning mode of the conventional transmission electron microscope. Backscattered electron imaging provided definitive identification of the gold markers while secondary electron imaging gave information on surface architecture. Labeling intensity was 250–800 gold particles per cell in Chinese hamster ovary cells and 600–2000 in CEM‐SS human lymphoblasts. The finding of hsp60 on the cell surface of mammalian cells may signify chaperone involvement in surface functions.