bluuebunny/crossref_metadata_2025_split huggingface dataset:
The arrest gene is required for germline cyst formation during Drosophila oogenesis
Authors: Parisi Michael J. , Deng Wei , Wang Zhong , Lin Haifan 
Published: August 2002

AbstractSummary: In Drosophila, oogenesis is initiated when a germline stem cell produces a differentiating daughter cell called the cystoblast. The cystoblast undergoes four rounds of synchronous divisions with incomplete cytokinesis to generate a syncytial cyst of 16 interconnected cystocytes, in which one cystocyte differentiates into an oocyte. Strong mutations of the arrest (aret) gene disrupt cyst formation and cause the production of clusters of ill‐differentiated germline cells that retain cellular and molecular characteristics of cystoblasts. These mutant germ cells express high levels of BAM‐C and SXL proteins in the cytoplasm but do not accumulate markers for advanced cystocytes or differentiating oocytes, such as the nuclear localization of SXL or the accumulation of osk mRNA, orb mRNA, and cytoplasmic dynein. However, the mutant germ cells do not contain spectrosomes, the cytoplasmic structure that objectifies the divisional asymmetry of the cystoblast. The aret mutant germ cells undergo active mitosis with complete cytokinesis. Their mitosis is accompanied by massive necrosis, so that the number of germ cells in a stem cell‐derived cluster ranges from one to greater than 70. These defects of aret mutants reveal a novel function of aret as the first gene with a defined function in the cystoblast to cyst transition during early oogenesis. genesis 29:196–209, 2001. © 2001 Wiley‐Liss, Inc.
Activation of epiblast gene expression by the hypoblast layer in the prestreak chick embryo
Authors: Knezevic Vladimir , Mackem Susan 
Published: August 2002

AbstractSummary: Axis formation is a highly regulated process in vertebrate embryos. In mammals, inductive interactions between an extra‐embryonic layer, the visceral endoderm, and the embryonic layer before gastrulation are critical both for anterior neural patterning and normal primitive streak formation. The role(s) of the equivalent extra‐embryonic endodermal layer in the chick, the hypoblast, is still less clear, and dramatic effects of hypoblast on embryonic gene expression have yet to be demonstrated. We present evidence that two genes later associated with the gastrula organizer (Gnot‐1 and Gnot‐2) are induced by hypoblast signals in prestreak embryos. The significance of this induction by hypoblast is discussed in terms of possible hypoblast functions and the regulation of axis formation in the early embryo. Several factors known to be expressed in hypoblast, and retinoic acid, synergistically induce Gnot‐1 and Gnot‐2 expression in blastoderm cell culture. The presence of retinoic acid in prestreak embryos has not yet been directly demonstrated, but exogenous retinoic acid appears to mimic the effects of hypoblast rotation on primitive streak extension, raising the possibility that retinoid signaling plays some role in the pregastrula embryo. genesis 30:264–273, 2001. © 2001 Wiley‐Liss, Inc.
Consanguinity and the transmission/disequilibrium test for allelic association
Authors: Bennett S. , Curnow R.N. 
Published: August 2002

AbstractConsanguineous marriages, usually between first cousins or between uncle and niece, are common in certain societies. The transmission/disequilibrium test (TDT) compares the transmission from parents to an affected child of alleles at a marker locus, and differential transmission indicates linkage and allelic association between the marker locus and a disease locus. We investigate the consequences for the TDT, as a test for allelic association, of consanguineous marriages. For each parental marker mating type, we calculate the frequency of each disease mating type, and the associated probability that an offspring is affected. We use Bayes’ Theorem to estimate the probability that an affected child inherits the given allele from a heterozygous parent, then combine our results across marker mating types. The effect of consanguineous marriage is usually small. For candidate genes, the effects were greater for uncle‐niece marriages, for rare disease alleles, and for high genotype relative risk. For markers, the effects were generally negligible. The Type I error probability of the TDT is essentially unchanged by intermarriage, except for a purely recessive disease allele. The power of the TDT is increased for a recessive allele and decreased for a dominant allele. However, consideration of levels of consanguinity that arise in practice indicates that standard power calculations for the TDT will usually need only minor modification. Genet. Epidemiol. 21:68–77, 2001. © 2001 Wiley‐Liss, Inc.
Modifications in astrocyte morphology and calcium signaling induced by a brain capillary endothelial cell line
Authors: Yoder Elizabeth J. 
Published: August 2002

AbstractAstrocytes extend specialized endfoot processes to perisynaptic and perivascular regions, and thus are positioned to mediate the bidirectional flow of metabolic, ionic, and other transmissive substances between neurons and the blood stream. While mutual structural and functional interactions between neurons and astrocytes have been documented, less is known about the interactions between astrocytes and cerebrovascular cells. For example, although the ability of astrocytes to induce structural and functional changes in endothelial cells is established, the reciprocity of brain endothelial cells to induce changes in astrocytes is undetermined. This issue is addressed in the present study. Changes in primary cultures of neonatal mouse cortical astrocytes were investigated following their coculture with mouse brain capillary endothelial (bEnd3) cells. The presence of bEnd3 cells altered the morphology of astrocytes by transforming them from confluent monolayers into networks of elongated multicellular columns. These columns did not occur when either bEnd3 cells or astrocytes were cocultured with other cell types, suggesting that astrocytes undergo specific morphological consequences when placed in close proximity to brain endothelial cells. In addition to these structural changes, the pharmacological profile of astrocytes was modified by coculture with bEnd3 cells. Astrocytes in the cocultures showed an increased Ca2+ responsiveness to bradykinin and glutamate, but no change in responsiveness to ATP, as compared to controls. Coculturing the astrocytes with a neuronal cell line resulted in increased responsiveness of the glial responses to glutamate but not to bradykinin. These studies indicate that brain endothelial cells induce changes in astrocyte morphology and pharmacology. GLIA 38:137–145, 2002. © 2002 Wiley‐Liss, Inc.
Interferon‐γ, tumor necrosis factor‐α, and transforming growth factor‐β inhibit cyclic AMP‐induced Schwann cell differentiation
Authors: Lisak Robert P. , Bealmear Beverly , Benjamins Joyce A. , Skoff Anne M. 
Published: August 2002

AbstractSchwann cells differentiate in vivo in response to contact with axons, and cAMP simulates some of these aspects of differentiation in vitro, particularly morphologic changes and expression of certain phenotypic molecules. Unfractionated inflammatory cytokines inhibit cAMP‐induced Schwann cell expression of galactolipids (Gal). We sought to identify which cytokines were responsible for this inhibition and to determine whether other phenotypic indicators of Schwann cell differentiation were also affected. Neonatal rat Schwann cells were incubated in vitro with 1 mM 8 Bromo cAMP (8 Br cAMP) with or without the addition of interleukin‐1α (IL‐1α), IL‐1β, IL‐2, IL‐6, tumor necrosis factor‐α (TNF‐α), interferon‐γ (IFN‐γ), or transforming growth factor‐β (TGF‐β). Cells were then examined for morphologic changes and for expression of surface Gal and low‐affinity nerve growth factor receptor (NGFRp75), employing indirect immunofluorescence. 8 Br cAMP induced Schwann cell upregulation of Gal, downregulation of NGFRp75, and the cells became enlarged and somewhat amorphous and irregular in appearance. Cells treated with IFN‐γ or TNF‐α alone were more bipolar and more evenly distributed on coverslips than were control cells, whereas TGF‐β alone induced elongated cells often in a swirling pattern. None of the cytokines alone induced upregulation of Gal or downregulation of NGFRp75. TNF‐α, IFN‐γ, and TGF‐β inhibited the 8 Br cAMP‐induced morphologic changes, as well as the upregulation of Gal and downregulation of NGFRp75. The other cytokines had no effects on Gal or NGFRp75 expression. Thus, these three cytokines, which are present in inflammatory lesions in the peripheral nervous system, are capable of inhibiting Schwann cell differentiation. GLIA 36:354–363, 2001. © 2001 Wiley‐Liss, Inc.
Cortical activation during Braille reading is influenced by early visual experience in subjects with severe visual disability: A correlational fMRI study
Authors: Melzer Peter , Morgan Victoria L. , Pickens David R. , Price Ronald R. , Wall Robert S. , Ebner Ford F. 
Published: August 2002

AbstractFunctional magnetic resonance imaging was performed on blind adults resting and reading Braille. The strongest activation was found in primary somatic sensory/motor cortex on both cortical hemispheres. Additional foci of activation were situated in the parietal, temporal, and occipital lobes where visual information is processed in sighted persons. The regions were differentiated most in the correlation of their time courses of activation with resting and reading. Differences in magnitude and expanse of activation were substantially less significant. Among the traditionally visual areas, the strength of correlation was greatest in posterior parietal cortex and moderate in occipitotemporal, lateral occipital, and primary visual cortex. It was low in secondary visual cortex as well as in dorsal and ventral inferior temporal cortex and posterior middle temporal cortex. Visual experience increased the strength of correlation in all regions except dorsal inferior temporal and posterior parietal cortex. The greatest statistically significant increase, i.e., ∼30%, was in ventral inferior temporal and posterior middle temporal cortex. In these regions, words are analyzed semantically, which may be facilitated by visual experience. In contrast, visual experience resulted in a slight, insignificant diminution of the strength of correlation in dorsal inferior temporal cortex where language is analyzed phonetically. These findings affirm that posterior temporal regions are engaged in the processing of written language. Moreover, they suggest that this function is modified by early visual experience. Furthermore, visual experience significantly strengthened the correlation of activation and Braille reading in occipital regions traditionally involved in the processing of visual features and object recognition suggesting a role for visual imagery. Hum. Brain Mapping 14:186–195, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of visual display techniques for assembly sequence planning
Authors: Gerace Janet , Gallimore Jennie J. 
Published: August 2002

AbstractThis study examined the effects of visual display formats for assembly planning tasks. A single assembly sequence was presented in: (a) a nonintegrated display format containing an arc and node diagram with an exploding graphic view of each step, and (b) an integrated display that incorporated pictures in the arc and node diagram and allowed enlargement of nodes. Both displays were tested with and without verbal and contextual information using five assembly rules. Overall, participants performed better and preferred the integrated display. Performance depended on the type of rule being examined. An integrated display format with verbal and contextual information is recommended for assembly sequence visualization. © 2001 John Wiley & Sons, Inc.
An experimental investigation of heat transfer in pin fin array
Authors: Dong Suyan , Liu Songling , Su Hongzhen 
Published: August 2002

AbstractDetailed heat transfer measurements were performed by using 178 thermocouples in a channel with pin fin array. Local heat transfer coefficients and local heat transfer enhancement coefficients were obtained for eight Reynolds numbers ranging from 2000 to 100,000 on the endwall of the channel. The endwall boundary conditions for heat transfer investigation are heating the bottom endwall and heating symmetrically the bottom and top endwalls with constant heat flux. The mechanism of heat transfer enhancement with pin fin array has been discussed. © 2001 Scripta Technica, Heat Trans Asian Res, 30(7): 533–541, 2001
Airflow and thermal conductance in a totally enclosed induction motor
Authors: Takahashi Kenji , Kuwahara Heikichi , Kajiwara Kenzou , Obata Takeshi 
Published: August 2002

AbstractHeat transfer coefficients of air‐cooled fins located on the outer surface of a totally enclosed induction motor were measured. It was found that the heat transfer coefficient decreases in the downstream direction in relation to the outer fins. It was also found that increasing the axial length of the fan cover (i.e., so that the fan cover overlaps the fin) increases the average heat transfer coefficient of the outer fins. Internal airflow induced by the rotor fan inside the motor end‐bracket coincides with the rotational speed of the rotor fan. Airflow velocity between the stator coil end and the housing in the motor is low, so a cooling structure with an inside ventilation passage for airflow was introduced to increase the heat transfer of the stator coil. By using an actual motor, the effect of resin (varnish) between the stator and the motor housing on the thermal‐contact conductance was determined; the thermal‐contact conductance of a motor with resin was 1.58 times higher than that of one without resin. © 2001 Scripta Technica, Heat Trans Asian Res, 31(1): 7–20, 2002
An experimental study of heat transfer in an open thermosyphon
Authors: Imai Etsuya , Shiina Yasuaki , Hishida Makoto 
Published: August 2002

AbstractAn experimental study was performed on heat transfer of an open thermosyphon with constant wall heat flux. Water and aqueous glycerin were used as working fluids. The experimental range of modified Rayleigh number was 1 × 103 < Ram < 3 × 105. The average and local heat transfer coefficients, vertical temperature distributions of the tube wall and fluid at the centerline of the tube, and temperature fluctuations of the fluid were measured. Flow patterns were observed by adding tracer powder to the fluid. Fluid velocities were measured by laser Doppler velocimeter. Experimental results indicate that, for a water thermosyphon, there are three regimes where different heat transfer characteristics and flow patterns occur. For 1 × 103 < Ram < 3 × 103, the flow was laminar and the thermal boundary layer reached the center of the tube. Heat was exchanged between the wall and descending flow. Wall temperature increased in the downward direction. For 4 × 103 < Ram < 3 × 104, no turbulence was observed in the flow and the thermal boundary layer was localized in the vicinity of the wall. The wall temperature increased upward. For 3 × 104 < Ram < 3 × 105, flow was considerably disturbed by the mixing of upward and downward flow in the upper part of the tube. However, the flow was laminar in the lower part of the tube. Reduction of the flow rate induced by the flow mixing at high Ram can be one of the major causes of the deterioration of heat transfer from Lighthill's theory. © 2001 Scripta Technica, Heat Trans Asian Res, 30(4): 301–312, 2001
Effects of density distribution of growing frost layer on radiation transfer
Authors: Yoshida Atsumasa , Haida Takeshi , Matsumoto Eiji , Washio Seiichi 
Published: August 2002

AbstractOur main interest concerned the effects of the density distribution on radiation transfer in scattering media. The frost layer in the early growth stage under the control of diffusion was chosen as the media. Numerical analysis of the radiation transfer was carried out by using a modified Monte Carlo method on the basis of geometrical optics. A diffusion‐limited aggregation theory was introduced to simulate the growth of a frost layer with a treelike structure. The relation between the density distribution and the transmittance of the simulated model was made clear by the numerical analysis. On the basis of these results, optical measurements in the visible wavelength region were utilized to evaluate the density distribution in the frost layer, which varied with cooling condition, on the transmittance values. © 2001 Scripta Technica, Heat Trans Asian Res, 30(5): 439–450, 2001
Natural convection of a water‐fine particle suspension in a rectangular cell heated and cooled from opposing vertical walls: The effect of distribution of particle size
Authors: Okada Masashi , Kang Chaedong , Oyama Kazuya , Yano Satoshi 
Published: August 2002

AbstractA water‐fine particle suspension with a uniform initial temperature and concentration in a rectangular cell was heated from a vertical wall and cooled from the opposing vertical wall. The dispersed particles had a distribution in size. In this natural convection, many layers separated by almost‐horizontal sharp interfaces were observed. In the beginning many layers appear, and each interface of the layers falls gradually with a constant velocity, and finally all layers vanish. To clarify this phenomenon, concentrations and mean diameters of the particles in each layer and temperature distributions were measured. Moreover, natural convection of the other suspension with particles which had a narrow size distribution was also investigated. © 2001 Scripta Technica, Heat Trans Asian Res, 30(8): 636–647, 2001
The dynamics of subsurface water divides—watersheds of Lake Stechlin and neighbouring lakes
Authors: Holzbecher Ekkehard 
Published: August 2002

AbstractUndoubtedly watersheds and their limiting groundwater divides are not steady but change. Nevertheless the temporal and spatial scales of the changes are seldom explored and rarely can be quantified. The Lake Stechlin region offers the exceptional chance to study the transient dynamics of catchments, the movement of subsurface water divides and their disappearance and reappearance. Based on long‐term data of surface water and groundwater levels a computer model delivers illustrative pictures of the dynamics of natural water bodies. A simple analytically derived criterion for the occurrence of groundwater divides shows remarkable coincidence with observations and with the output from the numerical model. Copyright © 2001 John Wiley & Sons, Ltd.
Controls on runoff components on a forested slope and implications for N transport
Authors: Buttle J. M. , Lister S. W. , Hill A. R. 
Published: August 2002

AbstractTransfer of atmospheric N deposition on shallow‐soil forested basins on the Canadian Shield to receiving water bodies may be enhanced by rapid preferential flow along the soil–bedrock interface (BR runoff) on basin slopes. Controls on BR runoff, partitioning of event and pre‐event water contributions to this flow, and implications of this partitioning for N fluxes in BR runoff were studied under natural and artificial inputs to an instrumented slope. BR runoff as a fraction of water inputs to the slope increased with antecedent soil wetness and input depth. Event water contributions to BR runoff initially increased with antecedent soil wetness, but then declined at large antecedent soil wetness. Export of applied NH4+ from the slope was maximized when event water contributions containing large NH4+ concentrations dominated BR runoff; however, there was no relationship between the fraction of NO3− application transported in BR runoff and either application input or the event water fraction of that runoff. The applicability of our results to other shallow‐soil areas of the Canadian Shield is limited by artificial N inputs to the slope in excess of natural loads and by low rates of N mineralization and negligible nitrification in the slope's soils. Nevertheless, the study reinforces the need to consider how the hydrologic, geometric and pedologic properties of forest slopes interact with biotic and abiotic soil processes to control N transport and transformation. Copyright © 2001 John Wiley & Sons, Ltd.
Analytical solutions of water table variation in a horizontal unconfined aquifer: Constant recharge and bounded by parallel streams
Authors: Kim Dong‐Ju , Ann Myeong‐Joon 
Published: August 2002

AbstractAnalysis of groundwater flow in an unconfined aquifer has received increasing attention by hydrogeologists for the design of drainage systems or the prediction of drawdown patterns of the water table in an aquifer neighbouring a pumping well. In this study, we attempt to analyse mathematically the variation of the water table in a horizontal unconfined aquifer receiving uniform recharge and bounded by parallel streams during a continuous cycle of rising and falling head conditions. The Boussinesq equation was taken to be the governing equation describing the transient changes in the water table. This problem was simplified to a one‐dimensional heat equation based on the assumption that the aquifer thickness is large enough compared to the water table changes and that the Dupuit–Forchheimer approximations are valid. We solved the heat equation using a method of variable separation in which the solution consists of both the steady‐state and nonsteady‐state solutions. With this method, the solutions could be obtained for various initial conditions such as different heads at the left and right boundaries and variable head distribution. In addition, simultaneous analysis of water table changes for both rising and falling head cases could be obtained. Comparison with other analytical solutions obtained for the linearized Boussinesq equation with Laplace transformation gives a nearly identical result, supporting the validity of the assumption and mathematical method used in this study. Advantages of the method over Laplace transformation can be found from the fact that our method renders the initial condition more flexible and simultaneous analysis of water table changes during rising and falling head cases can be done. Copyright © 2001 John Wiley & Sons, Ltd.
Evidence of high incidence of EGFRvIII expression and coexpression with EGFR in human invasive breast cancer by laser capture microdissection and immunohistochemical analysis
Authors: Ge Hong , Gong Xiaoqi , Tang Careen K. 
Published: August 2002

AbstractEGFRvIII was first reported in human glioblastomas. Subsequent reports indicated EGFRvIII protein to be frequently detected in several other human cancers, but not in normal tissues. Our previous studies suggested that EGFRvIII could induce a transformation from ligand‐dependent non‐tumorigenic cell line to ligand‐independent malignant phenotype cells in vitro and in vivo. Transfection of EGFRvIII in MCF‐7 cell line resulted in a 3‐fold increase in colony formation and significantly enhanced tumorigenicity in nude mice (p < 0.001). EGFRvIII could also induce ErbB‐2 phosphorylation. The existence and significance of EGFRvIII transcript in human breast cancer, however, was not reported. In our study, we detected the presence of EGFRvIII mRNA and revealed a high incidence (67.8%) of EGFRvIII transcript in human primary invasive breast cancer by utilizing laser capture microdissection (LCM)/RT‐PCR to capture pure breast cancer cells. In addition, 57.1% of the infiltrating breast carcinomas expressed both EGFRwt and EGFRvIII mRNA in the same tumor. There is no detectable EGFRvIII mRNA in normal breast tissue. Evaluation of the EGFRwt and EGFRvIII protein levels in the same sample sets by immunohistochemical analysis further confirmed the LCM/RT‐PCR finding. Our study provides first direct evidence of high incidence of coexpression of EGFRvIII and EGFRwt in human invasive breast cancer tissue. The unique characteristics and high prevalence of EGFRvIII in invasive human breast cancer as well as negative expression in normal breast may suggest its important role in breast carcinogenesis and make it an ideally potential target for treatment of breast cancer without interrupting normal EGFR signaling. © 2002 Wiley‐Liss, Inc.