bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rational regime model of alluvial channel morphology and response
Authors: Eaton Brett C. , Church Michael , Millar Robert G. 
Published: April 2004

AbstractA theoretical model is developed for predicting equilibrium alluvial channel form. The concept of greatest relative stability, achieved by maximizing resistance to ﬂow in the ﬂuvial system, is presented as the basis for an optimization condition for alluvial systems. Discharge, sediment supply (quantity and calibre) and valley gradient are accepted as independent governing variates. The model is used to deﬁne a dimensionless alluvial state space characterized by aspect ratio (W/d), relative roughness (D/d), and dimensionless shear stress (τ*) or, equivalently, channel slope (S). Each alluvial state exhibits unique values of Froude number and sediment concentration. The range of alluvial states for constant values of relative bank strength (parameterized by an apparent friction angle, ϕ′) forms a single plane in the state space (W/d, D/d, τ* or S). The scaling relations produced by the model are consistent with laboratory channels exhibiting a range of bank strengths, and with the behaviour of natural channels. Copyright © 2004 John Wiley & Sons, Ltd.
Robustness of alternative non‐linearity tests for SETAR models
Authors: Chan Wai‐Sum , Ng Man‐Wai 
Published: April 2004

AbstractIn recent years there has been a growing interest in exploiting potential forecast gains from the non‐linear structure of self‐exciting threshold autoregressive (SETAR) models. Statistical tests have been proposed in the literature to help analysts check for the presence of SETAR‐type non‐linearities in an observed time series. It is important to study the power and robustness properties of these tests since erroneous test results might lead to misspecified prediction problems. In this paper we investigate the robustness properties of several commonly used non‐linearity tests. Both the robustness with respect to outlying observations and the robustness with respect to model specification are considered. The power comparison of these testing procedures is carried out using Monte Carlo simulation. The results indicate that all of the existing tests are not robust to outliers and model misspecification. Finally, an empirical application applies the statistical tests to stock market returns of the four little dragons (Hong Kong, South Korea, Singapore and Taiwan) in East Asia. The non‐linearity tests fail to provide consistent conclusions most of the time. The results in this article stress the need for a more robust test for SETAR‐type non‐linearity in time series analysis and forecasting. Copyright © 2004 John Wiley & Sons, Ltd.
Entorhinal deafferentation induces the expression of profilin mRNA in the reactive microglial cells in the hippocampus
Authors: Dong Jing‐Hui , Ying Guo‐Xin , Zhou Chang‐Fu 
Published: April 2004

AbstractProfilin has been identified as an actin monomer sequestering protein and is thought to be a key regulator of actin polymerization in many fundamental cellular processes. We report the expression of profilin mRNA in the murine hippocampus following transections of the entorhinal afferents. Northern blot analysis showed that transcript of profilin was upregulated in a transient manner in the deafferented rat hippocampus by 1.5‐, 1.9‐, 1.4‐, and 1.1‐fold of controls, respectively, at 1, 3, 7, and 15 days post‐lesion. In situ hybridization confirmed the temporal upregulation of profilin mRNA in the deafferented zones of the mouse hippocampus, which showed a remarkable increase as early as at 1 day post‐lesion, reached maximal level at 3 days post‐lesion, and returned to the control level at 15 days post‐lesion. The expression modulation of profilin mRNA was observed to occur specifically in the entorhinally denervated zones: the stratum lacunosum‐moleculare of the hippocampus and the outer molecular layer of the dentate gyrus. The combination of in situ hybridization for profilin mRNA with lectin cytochemistry for Griffonia simplicifolia IB4 showed that the cells expressing profilin transcript in the denervated zones are activated microglial cells. The results suggest that the spatial and temporal upregulation of profilin mRNA in the hippocampus is induced by entorhinal deafferentation and profilin is involved in microglial activation associated with morphological change, migration, and phagocytic behavior of microglial cells. © 2004 Wiley‐Liss, Inc.
Heterogeneity and potentiation of AMPA type of glutamate receptors in rat cultured microglia
Authors: Hagino Yukiko , Kariura Yukihiro , Manago Yoshimasa , Amano Taiju , Wang Bing , Sekiguchi Masayuki , Nishikawa Kaori , Aoki Shunsuke , Wada Keiji , Noda Mami 
Published: April 2004

Abstractα‐amino‐hydroxy‐5‐methyl‐isoxazole‐4‐propionate (AMPA) receptor in rat cultured microglia were analyzed precisely using flop‐ and flip‐preferring allosteric modulators of AMPA receptors, 4‐[2‐(phenylsulfonylamino)ethylthio]‐2,6‐difluoro‐phenoxyacetamide (PEPA) and cyclothiazide (CTZ), respectively. Glutamate (Glu)‐ or kainite (KA)‐induced currents were completely inhibited by a specific blocker of AMPA receptor, LY300164, indicating that functional Glu‐receptors in cultured microglia are mostly AMPA receptor but not KA receptor in many cells. Glu‐ and KA‐induced currents were potentiated by PEPA and CTZ in a concentration‐dependent manner. The ratio of the potentiation by PEPA to the potentiation by cyclothiazide varied with cells between 0.1 and 0.9, suggesting cell‐to‐cell heterogeneity of AMPA receptor subunits expressed in microglia. Quantitative RT‐PCR revealed that GluR1‐3 mainly occurred in the flip forms, which agreed with the stronger potentiation of receptor currents by CTZ vs. PEPA. Finally, the potentiation of microglial AMPA receptors by PEPA and CTZ inhibited the Glu‐induced release of tumor necrosis factor‐α (TNF‐α) unpredictably. The increase in TNF‐α release by Glu or KA required extracellular Na+ and Ca2+ ions but not mitogen‐activated protein kinase (MAPK), suggesting the effects of PEPA and CTZ were not due to the inhibition of MAPK. These results suggest that potentiation of microglial AMPA receptors serves as a negative feedback mechanism for the regulation of TNF‐α release and may contribute to the ameliorating effects of allosteric modulators of AMPA receptors. © 2004 Wiley‐Liss, Inc.
33S NMR shieldings and chemical bonding in compounds of sulfur
Authors: Chesnut D. B. , Quin L. D. 
Published: April 2004

AbstractSulfur nuclear magnetic resonance (NMR) chemical shieldings have been determined at the correlation‐including density functional theory scaled B3LYP/6‐311+G(nd,p)//B3LYP/6‐311+G(d,p) and modified MP2/6‐311+G(nd,p) estimated infinite order Møller‐Plesset levels with n = 2 for sulfur. The calculations span the range of sulfur shieldings and show agreement with experiment of about 3% of the shielding range. The atoms‐in‐molecules delocalization index and a covalent bond order from specific localized orbitals in the DFT approach are used to characterize sulfur's bonding and to relate it, where possible, to the calculated shieldings. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:216–224, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20000
Application of alkoxy‐λ6‐sulfanenitriles as strong alkylating reagents
Authors: Hao Wei , Fujii Takayoshi , Dong Tiaoling , Wakai Youko , Yoshimura Toshiaki 
Published: April 2004

AbstractAlkoxy‐λ6‐sulfanenitriles were found to be versatile alkylating reagents toward various nucleophiles bearing at least one proton such as methanol, phenol, thiophenols, carboxylic acids, p‐toluenesulfonic acid, hydrochloric acid, and primary and secondary amines. Reactivity of the alkoxy group of the λ6‐sulfanenitriles showed an opposite trend to the usual SN2 character, i.e. Me (1a), Pr (1b), and Bu (1d) ≪ i‐Pr (1c). In the presence of p‐TsOH, alkyl tosylates were predominantly formed instead of the alkylation products of nucleophiles. In addition, even a sterically hindered substrate, neopentyloxy‐λ6‐sulfanenitrile, was found to undergo an SN2 reaction toward thiophenol without any rearrangement product to give neopentyl phenyl sulfide in good yield. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:193–198, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20006
Disilyl dithiophosphonates in the synthesis of open chain and cyclic organothiophosphorus compounds
Authors: Nizamov Il'yas S. , Sergeenko Gul'nur G. , Nizamov Il'nar D. , Popovich Yan E. , Khaibullin Ravil N. , Al'metkina Lyubov A. , Abalonin Boris E. , Batyeva Elvira S. , Krivolapov Dmitry B. , Litvinov Igor A. 
Published: April 2004

AbstractO‐(Trimethylsiloxy)alkyl S‐trimethylsilyl aryldithiophosphonates 7a–d were obtained by the reaction of 2,4‐diaryl‐1,3,2,4‐dithiadiphosphetane‐2,4‐disulfides 5a,b with disilyl derivatives of glycols 6a,c and salicyl alcohol 6b. The reactions of mixed O,S‐bis(trimethylsilyl) 2,4‐di(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl)dithiophosphonate 1 and S‐silyl aryldithiophosphonates 7a,b with S,S‐diethyldithiodiphenylgermane 2, dichlorodiphenylgermane 8a, and dichlorodiphenylstannane 8b were studied. The structure of hexaphenyl‐2,4,6,1,3,5‐trithiatrigerminane 11 was established by X‐ray single crystal diffraction. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:225–232, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20009
Combining phosphinidene units with malonate anion: Synthesis of highly functional phosphine complexes
Authors: Compain Carine , Huy Ngoc Hoa Tran , Mathey François 
Published: April 2004

AbstractMalonate anion traps the [RP‐W(CO)5] bridge of 7‐phosphanorbornadiene complexes 1–3 to give functional secondary phosphine complexes [RP(H)‐CH(CO2Et)2]W(CO)5 (7–9). Metalation of these complexes by NaH in THF occurs at the malonic CH group, but the alkylation of the resulting carbanions preferentially takes place at phosphorus. When R stands for β‐chloroethyl, the corresponding carbanion cyclizes to give the functional phosphirane complex 11. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:258–262, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20014
Selective hippocampal damage in rhesus monkeys impairs spatial memory in an open‐field test
Authors: Hampton Robert R. , Hampstead Benjamin M. , Murray Elisabeth A. 
Published: April 2004

AbstractThe hippocampus is critical for remembering locations in a wide variety of species, including humans. However, recent findings from monkeys following selective hippocampal lesions have been equivocal. To approximate more closely the situations in which rodents and birds are tested, we used a spatial memory task in which rhesus monkeys (Macaca mulatta) moved about freely in a large room, on a tether. We used MRI‐guided stereotaxic surgery to produce selective hippocampal lesions in five monkeys, and retained five unoperated control monkeys. In the study phase of each trial of the matching‐to‐location task, monkeys found food in one site in an array of identical foraging sites. During the test, which occurred after a delay, monkeys could return to the site where the food had been found during study to obtain more food. In Experiment 1, normal monkeys showed a small significant tendency to return directly to a site where they had previously found food that day. Operated monkeys showed no such matching tendency. In Experiment 2, further training produced reliable matching‐to‐location performance in both groups at short delays, but monkeys with selective hippocampal lesions rapidly forgot the location of the food. In Experiment 3, we tested whether monkeys used a “cognitive map” to encode the location of the hidden food, by requiring them to relocate the food from a starting location different from that used during study. As a group, monkeys were more accurate than expected by chance, indicating that they did encode the rewarded location with respect to allocentric landmarks; however, both groups of monkeys were significantly worse at relocating the food when required to approach from a different location. In Experiment 4, probe trials using symmetrical test arrays found no evidence for egocentric coding of the rewarded location. © 2004 Wiley‐Liss, Inc.
Inhibition of a complement regulator in vivo enhances antibody therapy in a model of mammary adenocarcinoma
Authors: Imai Masaki , Ohta Rieko , Okada Noriko , Tomlinson Stephen 
Published: April 2004

AbstractMembrane‐bound complement regulatory proteins provide tumor cells with protection from antibody and complement in vitro. However, complement regulators are widely expressed on normal tissue, and inhibiting the function of complement regulatory proteins on tumor cells in vivo has not been investigated due to the absence of appropriate tumor‐targeting strategies. Using a mouse model of rat mammary adenocarcinoma, we demonstrate that tumor‐specific targeting of a complement regulator with a blocking antibody has functional consequences with regard to both complement deposition on tumor cells and the efficacy of monoclonal antibody therapy. Rat adenocarcinoma 13762 cells express Crry, a widely expressed rodent regulator of complement activation, and are recognized by C595 MAb, an anti‐MUC1 MAb in clinical trials. Anti‐rat Crry 5I2 MAb and F(ab)2 enhanced complement deposition on C595 MAb‐sensitized 13762 cells in vitro. In vivo, C595 MAb bound to 13762 tumors, albeit not specifically, but was not therapeutic when administered after tumor challenge. However, the coadministration of 5I2 MAb with C595 MAb resulted in enhanced complement deposition and significantly delayed tumor onset and reduced tumor growth; 5I2 MAb alone also enhanced complement deposition and reduced tumor growth but less effectively than when combined with C595 MAb; 5I2 MAb alone did not directly activate mouse complement, but its inhibitory effect on Crry enhanced complement deposition following complement activation by both the alternative pathway and by natural IgM reactive to 13762 cells present in mouse serum. Our proof of principle study shows that inhibiting the function of a tumor‐expressed complement regulatory protein enhances immune‐mediated clearance of tumor cells and improves prospects for successful immunotherapy. The results justify further research and development of targeting strategies to inhibit or downregulate complement regulatory proteins on tumor cells. © 2004 Wiley‐Liss, Inc.
Irradiated C6 glioma cells induce angiogenesis in vivo and activate endothelial cells in vitro
Authors: Parthymou Anastasia , Kardamakis Dimitris , Pavlopoulos Ionnis , Papadimitriou Evangelia 
Published: April 2004

AbstractMalignant gliomas are angiogenesis dependent and present a remarkable degree of resistance to radiotherapy. In the present work, we studied the effect of irradiation of C6 glioma cells on their proliferation and activation in vitro and on glioma cell‐induced angiogenesis in vivo and in vitro. Irradiation of C6 glioma cells decreased cell proliferation in a dose‐dependent manner. Interestingly, metalloproteinase‐2 and ‐9 expression and secretion, as well as integrin αv expression, increased with elevated doses of X rays 48 hr after irradiation and was mostly evident at the higher doses used. When pre‐irradiated C6 cells were implanted on nonirradiated chicken embryo chorioallantoic membranes (CAMs), there was a significant dose‐dependent increase in tumor induced angiogenesis, compared to angiogenesis induced by nonirradiated cells. Similar results were obtained when C6 cells were irradiated 48 hr after their inocculation onto nonirradiated CAMs. In the same line, conditioned medium from irradiated C6 cells significantly increased endothelial cell proliferation and migration in vitro, in a manner dependent on the dose of X rays. These results explain at least in part the low effectiveness of radiation therapy of malignant gliomas and support the notion that inhibition of angiogenesis in parallel with radiotherapy may represent a new therapeutic approach. © 2004 Wiley‐Liss, Inc.
Inhibition of the invasion capacity of carcinoma cells by WX‐UK1, a novel synthetic inhibitor of the urokinase‐type plasminogen activator system
Authors: Ertongur Suna , Lang Stephan , Mack Brigitte , Wosikowski Katja , Muehlenweg Bernd , Gires Olivier 
Published: April 2004

AbstractThe overall survival rate of patients suffering from carcinomas has remained poor and nearly unchanged over the last decades. This is mainly due to the so‐called minimal residual disease, i.e., remaining tumor cells that overcome surgery and/or radiotherapy and are the cause of locoregional and distant metastases. To metastasize, tumor cells take advantage of proteases to invade and remodel surrounding tissues. Here, we analyzed the efficiency of WX‐UK1, a novel 3‐amidinophenylalanine‐based inhibitor of the uPA system, at inhibiting the invasive capacity of carcinoma cells. First, uPAR expression was characterized in different carcinoma cell lines, including SCCHN, breast and cervical carcinoma. Thereafter, the invasive potential of these cell lines was determined using Matrigel invasion chambers and a spheroid cocultivation model with human fibroblasts. uPAR expression levels correlated positively with invasion capacity, which could be significantly inhibited by WX‐UK1. A decrease of tumor cell invasion by up to 50% was achieved in both models with the SCCHN line FaDu and the cervical carcinoma line HeLa after treatment with WX‐UK1. Thus, our results demonstrate the potential of WX‐UK1 in vitro as a promising adjuvant antimetastatic therapy of carcinomas. © 2004 Wiley‐Liss, Inc.
Pretreatment evaluation of combined HIF‐1α, p53 and p21 expression is a useful and sensitive indicator of response to radiation and chemotherapy in esophageal cancer
Authors: Sohda Makoto , Ishikawa Hitoshi , Masuda Norihiro , Kato Hiroyuki , Miyazaki Tatsuya , Nakajima Masanobu , Fukuchi Minoru , Manda Ryokuhei , Fukai Yasuyuki , Sakurai Hideyuki , Kuwano Hiroyuki 
Published: April 2004

AbstractTumor hypoxia has been known to be associated with resistance to radiation and chemotherapy (CRT). Hypoxia‐inducible factor‐1α (HIF‐1α), a transcription factor induced by hypoxic condition, plays a major role in the pleiotropic response observed under hypoxic conditions. It encodes proteins that play key roles in critical development and physiologic processes, including angiogenesis, glucose transport and erythropoiesis. On the other hand, cell cycle‐ and apoptosis‐control genes p53 and p21 may play major roles in the tumor response to cytotoxic agents such as radiation and chemotherapy. Previous reports have suggested that the regulation of p53 and p21 is HIF‐1‐dependent. Our aim was to evaluate the expression of the HIF‐1α, p53 and p21 proteins by immunohistochemistry in biopsy specimens of esophageal squamous cell carcinoma, which were obtained endoscopically from 65 patients before CRT, and then determine whether the levels of expression of these proteins predicted the clinical effectiveness of CRT in individual cancers. Also, to assess the relationship between expression of these proteins and cell death and cellular proliferation activity, we evaluated Ki67 expression and the apoptosis index (TUNEL). HIF‐1α expression in esophageal cancer was significantly and negatively related to the response to CRT, independently of p53 and p21 expression. Interestingly, 44.4% (12/27) of the HIF‐1α‐negative group showed a complete response to therapy. There was no significant correlation between the expression of HIF‐1α, p53 and p21 and proliferation and apoptosis. HIF‐1α overexpression may predict resistance to CRT and may be a helpful guide in choosing between therapeutic strategies, such as intensive combined modality therapy vs. palliative therapy. Combined immunohistochemical evaluation of HIF‐1α, p53 and p21 protein expression at the pretreatment biopsy is a very useful and powerful indicator of sensitivity to CRT in human esophageal cancer. Our data also indicate the importance of having a clear grasp of the degree of hypoxia (HIF‐1α) of a tumor, rather than its cellular character (proliferation and apoptosis), to indicate the likely impact of CRT. © 2004 Wiley‐Liss, Inc.
Evaluation of mRNA expression of estrogen receptor β and its isoforms in human normal and neoplastic endometrium
Authors: Skrzypczak Maciej , Bieche Ivan , Szymczak Sylwia , Tozlu Sengul , Lewandowski Sebastian , Girault Igor , Radwanska Katarzyna , Szczylik Cezary , Jakowicki Jerzy A. , Lidereau Rosette , Kaczmarek Leszek 
Published: April 2004

AbstractEndometrial cancer is well known to be estrogen‐dependent. Two estrogen receptor types, ERα and ERβ, are major mediators of a diversity of biologic functions of estrogen and play an important role in estrogen‐dependent tissues and cancers. Cloning of ERβ was followed by the discovery of a variety of its isoforms. Using real‐time RT‐PCR, the relative expression levels of ERβ1, ERβ2 (ERβcx), ERβ3, ERβ4 and ERβ5 were studied. We observed coexpression of ERβ isoforms in the endometrium and upregulation of the ERβ5 transcript in malignant endometrium. We also observed downregulation of ERβ2Δ5 transcript in neoplastic endometrium, using a semiquantitative method. Our results suggest that analyzing the changes in ERβ and its isoforms may be important in the diagnosis, prognosis and treatment of endometrial cancer. © 2004 Wiley‐Liss, Inc.
Effect of fibrous capsule formation on doxorubicin distribution in radiofrequency ablated rat livers
Authors: Blanco Elvin , Qian Feng , Weinberg Brent , Stowe Nicholas , Anderson James M. , Gao Jinming 
Published: April 2004

AbstractIn this study, we report the histological findings of a combined therapy using radiofrequency ablation and intratumoral drug delivery in rat livers, with special attention to wound‐healing processes and their effects on drug transport in post‐ablated tissue. Doxorubicin‐loaded millirods were implanted in rat livers that had undergone medial lobe ablation. Millirods and liver samples were retrieved upon animal sacrifice at time points ranging from 1 h to 8 days. Results demonstrate a clearly defined area of coagulative necrosis within the ablation boundary. The wound‐healing response, complete with the appearance of inflammatory cells, neovascularization, and the formation of a fibrous capsule, was also observed. At the 8‐day time point, fluorescence imaging analysis showed a higher concentration of doxorubicin localized within the ablation region, with its distribution hampered primarily by fibrous capsule formation at the boundary. Given the variant nature of ablated liver, a mathematical model devised previously by our laboratory describes the data well up to 4 days, but loses reliability at 8 days. These results provide useful mechanistic insights into the wound‐healing response after radiofrequency ablation and polymer millirod implantation, as well as the impact this natural corollary has on drug distribution. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 398–406, 2004