bluuebunny/crossref_metadata_2025_split huggingface dataset:
Highly Regioselective C(3) Opening of an Aromatic 2,3‐Epoxy Alcohol with Sodium Phenoxides or Thiophenoxides (=Benzenethiolates) Supported by β‐Cyclodextrin in Water
Authors: Narender Mendu , Reddy Majjigapu Somi , Nageswar Yadavalli Venkata Durga , Rao Kakulapati Rama 
Published: June 2007

AbstractA simple and mild procedure was developed for the first time for the C(3)‐selective ring opening of an aromatic 2,3‐epoxy alcohol, i.e., of trans‐3‐phenyloxirane‐2‐methanol (1), with sodium phenoxides or thiophenoxides (=benzenethiolates) 2 supported by β‐cyclodextrin in H2O at 50° to afford the corresponding 3‐(aryloxy)‐ or 3‐(arylthio)propane1,2‐diols 3 in excellent yields (Scheme, Table).
Effects of Micellar Aggregates on the Kinetics and Mechanism of the Reaction between 4‐Nitrobenzenediazonium Ions and Some Amino Acids
Authors: Fernández‐Alonso Alejandra , Bravo‐Díaz Carlos 
Published: June 2007

AbstractWe have explored the kinetics and mechanism of the reaction between 4‐nitrobenzenediazonium ions (4NBD), and the hydrophilic amino acids (AA) glycine and serine in the presence and absence of sodium dodecyl sulfate (SDS) micellar aggregates by means of UV/VIS spectroscopy. The observed rate constants kobs were obtained by monitoring the disappearance of 4NBD with time at a suitable wavelength under pseudo‐first‐order conditions. In aqueous acid (buffer‐controlled) solution, in the absence of SDS, the dependence of kobs on [AA] was obtained from the linear relationship found between the experimental rate constant and [AA]. At a fixed amino acid concentration, kobs values show an inverse dependence on acidity in the range of pH 5–6, suggesting that the reaction takes place through the nonprotonated amino group of the amino acid. All kinetic evidence is consistent with an irreversible bimolecular reaction with k=2390±16 and 376±7 M−1 s−1 for glycine and serine, respectively. Addition of SDS inhibits the reaction because of the micellar‐induced separation of reactants originated by the electrical barrier imposed by the SDS micelles; kobs values are depressed by factors of 10 (glycine) and 6 (serine) on going from [SDS]=0 up to [SDS]=0.05M. The hypothesis of a micellar‐induced separation of the reactants was confirmed by 1H‐NMR spectroscopy, which was employed to investigate the location of 4NBD in the micellar aggregate: the results showed that the aromatic ring of the arenediazonium ion is predominantly located in the vicinity of the C(β) atom of the surfactant chain, and hence the reactive N$\rm{ _2^ + }$ group is located in the Stern layer of the micellar aggregate. The kinetic results can be quantitatively interpreted in terms of the pseudophase kinetic model, allowing estimations of the association constant of 4NBD to the SDS micelles.
New Steryl Esters of Fatty Acids from the Mangrove Fungus Aspergillus awamori
Authors: Gao Hao , Hong Kui , Zhang Xue , Liu Hong‐Wei , Wang Nai‐Li , Zhuang Ling , Yao Xin‐Sheng 
Published: June 2007

AbstractThe polyhydroxylated ergostane‐type sterol 9, its derivatives 10–15, and the fatty acid esters 1–8 were isolated from a fungus strain which was collected from mangrove areas at Wenchang, Hainan Province, P. R. China, exhibited potent cytotoxic activity, and was identified as Aspergillus awamori. The structures of 1–15 were elucidated by spectroscopic and chemical methods. Among them, the six steryl esters 1–6 of fatty acids were new compounds, i.e., (3β,5α,6α,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐palmitate (1), (3β,5α,6α,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐stearate (2), (3β,5α,6α,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐oleate (3), (3β,5α,6α,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐linoleate (4), (3β,5α,6β,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐palmitate (5), and (3β,5α,6β,22E)‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐stearate (6). The related known fatty acids stearic acid (=octadecanoic acid) and palmitic acid (=octadecanoic acid) were also obtained. A speculative biogenetic relationship of the metabolites is proposed. The known polyhydroxylated sterols and derivatives showed cytotoxic activities, in agreement with earlier reports. The cytotoxic activities against B16 and SMMC‐7721 cell lines of the new steryl esters 1–6 by the MTT method were weak.
Preparation and Characteristics of Esculin‐Imprinted Polymers
Authors: Wang Guo‐Song , Cao Qiu‐E. , Ding Zhong‐Tao , Wang Yi‐Geng , Yang Ming‐Hui 
Published: June 2007

AbstractFour molecularly imprinted polymers (MIPs) were prepared in MeOH with esculin (=6,7‐dihydroxycoumarin 6‐(β‐D‐glucopyranoside)=6‐(β‐D‐glucopyranosyloxy)‐7‐hydroxy‐2H‐1‐benzopyran‐2‐one) as the imprinted molecule, methacrylic acid (=2‐methylprop‐2‐enoic acid; MAA), acrylamide (=prop‐2‐enamide; AM), 4‐vinylpyridine (=4‐ethenylpyridine; 4‐VP), or 2‐vinylpyridine (=2‐ethenylpyridine; 2‐VP) as the functional monomer, respectively, as well as ethylene glycol dimethacrylate (=2‐methylprop‐2‐enoic acid ethane‐1,2‐diyl ester; EGDMA) as the cross‐linking agent. The interaction between the template and the functional monomers was investigated by fluorescence and UV spectrophotometry, respectively, which revealed the presence of esculin/monomer complexes in the stoichiometric ratio 1 : 2 in the pre‐polymerization mixture. The resultant polymers were studied in equilibrium binding experiments to evaluate the recognition ability and the binding capacity towards esculin. The results showed that MIP1, prepared with MAA as the functional monomer, exhibited advantageous characteristics of high binding capacity, optimal imprinting effect, and good selectivity towards esculin. The Scatchard analysis indicated that there are two types of binding sites in MIP1, and its binding parameters including the apparent maximum numbers of binding sites and the dissociation constants were calculated. Finally, by packing an SPE column (SPE=solid‐phase extraction) with MIP1, the esculin was separated and enriched successfully by this sorbent from samples of Cortex fraxini, and the average recovery was up to 74.7%.
Prognostic factors for patients with acute myeloid leukaemia or high‐risk myelodysplastic syndromes undergoing myeloablative or non‐myeloablative allogeneic blood stem cell transplantation
Authors: Graef Thorsten , Vaupel Matthias , Fenk Roland , Ruf Leilani , Zohren Fabian , Germing Ulrich , Haas Rainer , Kobbe Guido 
Published: June 2007

AbstractIn this uni‐centre retrospective study, we studied 120 adults with acute myeloid leukaemia (AML) (n = 88) and myelodysplastic syndrome (MDS) (n = 32) who received first allogeneic HSCT to determine prognostic factors which are correlated with the outcome after myeloablative (MA) or non‐myeloablative (non‐MA) allogeneic HSCT. The median age of our cohort was 44 years. Fifty‐nine per cent of the patients were transplanted in complete remission (CR) and 41% were in relapse or refractory to induction or salvage therapy. A total of 97 patients received a MA regimen and 23 were treated with a non‐MA regimen. The prognostic impact for several parameters was assessed by univariate and by multivariate analyses using the Cox regression model. Three‐year probabilities of non‐relapse mortality (34 vs. 54%; p = 0.9) did not differ in the MA and non‐MA groups, but differences were observed in the disease‐free survival (DFS) (43 vs. 17%; p = 0.1) and the relapse rate (RR) (29 vs. 62%; p = 0.01). Independently from the regimen, in uni‐ and multivariate analysis, survival was best in those patients who were transplanted in CR and experienced cGvHD. Interestingly, outcome of patients with complex cytogenetic aberrations was identical to that of better prognostic subgroups. In this study, the clinical benefit of a lower toxicity regimen was offset by higher RR resulting in inferior results in the non‐MA group, especially when no CR was achieved by prior induction or salvage therapy. Copyright © 2007 John Wiley & Sons, Ltd.
Cereal fiber intake may reduce risk of gastric adenocarcinomas: The EPIC‐EURGAST study
Authors: M.A. Mendez , Pera Guillem , Agudo Antonio , Bueno‐de‐Mesquita H. Bas , Palli Domenico , Boeing Heiner , Carneiro Fátima , Berrino Franco , Sacerdote Carlotta , Tumino Rosario , Panico Salvatore , Berglund Göran , Manjer Jonas , Johansson Ingegerd , Stenling Roger , Martinez Carmen , Dorronsoro Miren , Barricarte Aurelio , Tormo María J. , Quiros José R. , Allen Naomi , Key Timothy J. , Bingham Sheila , Linseisen Jakob , Kaaks Rudolf , Overvad Kim , Jensen Majken , Olsen Anja , Tjønneland Anne , Peeters Petra H.M. , Numans Mattijs E. , Ocké Marga C. , Clavel‐Chapelon Françoise , Boutron‐Ruault Marie‐Christine , Trichopoulou Antonia , Lund Eiliv , Slimani Nadia , Jenab Mazda , Ferrari Pietro , Riboli Elio , González Carlos A. 
Published: June 2007

AbstractNumerous case‐control studies suggest dietary fiber may reduce risk of gastric cancer, but this has not been confirmed prospectively. A previous case‐control study reported reduced risk of gastric cardia adenocarcinomas associated with cereal fiber, but not with fruit or vegetable fiber. To date, different food sources of fiber have not been examined with respect to noncardia tumors or diverse histologic sub‐types. This study prospectively examines associations between fiber from different food sources and incident gastric adenocarcinomas (GC) among more than 435,000 subjects from 10 countries participating in the European Prospective Investigation into Cancer and Nutrition study. Subjects aged 25–70 years completed dietary questionnaires in 1992–98, and were followed up for a median of 6.7 years. About 312 incident GCs were observed. The relative risk of GC was estimated based on cohort‐wide sex‐specific fiber intake quartiles using proportional hazards models to estimate hazards ratios (HRs) and 95% confidence intervals (CIs). Intakes of cereal fiber, but not total, fruit or vegetable fiber, were associated with reduced GC risk [adjusted HR for the highest vs. lowest quartile of cereal fiber 0.69, 0.48–0.99]. There was a strong inverse association for diffuse [HR 0.43, 0.22–0.86], but not intestinal type [HR 0.98, 0.54–1.80] tumors. Associations for cardia vs. noncardia tumors were similar to those for overall GC, although cardia associations did not reach significance. Cereal fiber consumption may help to reduce risk of GC, particularly diffuse type tumors. Further study on different food sources of fiber in relation to GC risk is warranted to confirm these relationships. © 2007 Wiley‐Liss, Inc.
Cross‐talks between cyclooxygenase‐2 and tumor suppressor protein p53: Balancing life and death during inflammatory stress and carcinogenesis
Authors: de Moraes Emanuela , Dar Nazir Ahmad , de Moura Gallo Claudia Vitoria , Hainaut Pierre 
Published: June 2007

AbstractOverexpression of Cyclooxygenase‐2 (COX‐2) is observed in most tumor types. Increased COX‐2 activity and synthesis of prostaglandins stimulates proliferation, angiogenesis, invasiveness and inhibits apoptosis. Many stress and proinflammatory signals induce COX‐2 expression, including oxyradicals or DNA‐damaging agents. The latter also induces p53, a transcription factor often inactivated by mutation in cancer. Several studies have identified complex cross‐talks between p53 and COX‐2, whereby p53 can either up‐ or down‐regulate COX‐2, which in turn controls p53 transcriptional activity. However, the molecular basis of these effects are open to debate, in particular since no p53 binding sequences have been identified in COX‐2 regulatory regions. In this review, we summarize the molecular mechanisms by which COX‐2 contributes to carcinogenesis and discuss the experimental set‐up, results and conclusions of studies analyzing cross‐talks between p53 and COX‐2. We propose 2 scenarios accounting for overexpression of COX‐2 in precursor and cancer lesions. In the “inflammatory” scenario, p53, activated by DNA damage induced by oxygen and nitrogen species, recruits NF‐kappaB to activate COX‐2, resulting in antiapoptotic effects that contribute to cell expansion in inflammatory precursor lesions. In the “constitutive proliferation” scenario, oncogenic stress due to activation of growth signaling cascades may upregulate COX‐2 promoter independently of NF‐kappaB and p53, synergizing with TP53 mutation to promote cancer progression. These 2 scenarios, although not mutually exclusive, may account for the diversity of the correlations between COX‐2 expression and TP53 mutation, which vary according to cancer types and biological contexts, and have implications for the use of COX‐2 inhibitors in cancer prevention and therapy. © 2007 Wiley‐Liss, Inc.
Glioma immunotherapy by IL‐21 gene‐modified cells or by recombinant IL‐21 involves antibody responses
Authors: Daga Antonio , Orengo Anna Maria , Gangemi Rosaria Maria Rita , Marubbi Daniela , Perera Marzia , Comes Alberto , Ferrini Silvano , Corte Giorgio 
Published: June 2007

AbstractMost tumors of the central nervous system, especially glioblastoma, are refractory to treatment and invariably lethal. The aim of this study was to assess the ability of different interleukins (IL), IL‐2, IL‐12 and IL‐21, produced by transduced glioma cells to activate an immune response and trigger intracranial tumor rejection. Such experiments were performed by the use of a slow‐growing clone of GL261 (GL D2‐60) that was used as orthotopic glioma model. Using GL D2‐60‐transduced cells, all cytokines elicited an immune response against the tumor. Most notably 100% of the animals receiving a primary implant of IL‐21‐transduced cells rejected the implant, and 76% of these animals survived to a subsequent rechallenge with GL261 parental cells, while the other transduced cytokine genes were not as effective. Rejection responses were also obtained by admixing wild‐type tumor cells with IL‐21‐producing GL D2‐60 cells, indicating a local bystander effect of IL‐21. More importantly, IL‐21‐secreting GL D2‐60 cells or 1 μg of rIL‐21 protein stereotactically injected into established GL D2‐60 tumors were able to trigger glioblastoma rejection in 90 and 77% of mice, respectively. Again most of these mice survived to GL261 rechallenge. Immune mice showed antibody responses to glioma antigens, predominantly involving IgG2a and IgG2b isotypes, which mediated complement‐ or cell‐dependent glioma cell lysis. Antibody responses were crucial for glioma immunotherapy by IL‐21‐secreting GL D2‐60 cells, as immunotherapy was uneffective in syngeneic μMT B‐cell‐deficient mice. These results suggest that IL‐21 should be considered as a suitable candidate for glioma immunotherapy by local delivery. © 2007 Wiley‐Liss, Inc.
Framework for participatory assessments and implementation of global environmental conventions at the community level
Authors: Oba G. , Sjaastad E. , Roba H. G. 
Published: June 2007

AbstractParticipation by local communities in the assessment and monitoring of efforts to implement global environmental conventions (GECs), such as Convention on Biological Diversity (CBD) and the UN Convention to Combat Desertification (UNCCD), is a topic of growing interest worldwide. Previous implementation efforts were constrained by the lack of a methodological framework that integrates local knowledge and ecological methods. This study, conducted with assistance from Maasai herders in northern Tanzania, evaluated a socio‐economic and ecological framework for integrating local communities into assessments of the GECs. To reach decisions related to CBD, herders used livestock grazing suitability (GS) and proxy indicators of biodiversity, while to reach decisions related to CCD herders used potential grazing capacity (PGC) related to the risk of degradation. We proposed criteria for indicator selection and developed step‐wise research methods to assess performance of the indicators at spatial scales. The ecological and anthropogenic indicators were then analysed using a correlation matrix to evaluate management decisions. We showed that changes in ecological indicators influenced herder decisions. The anthropogenic indicators for potential were more sensitive to changes in soil degradation, range conditions and trends; while the decisions related to GS were more sensitive to the majority of the proxy indicators of biodiversity. The decisions reflected the potential responses to management, which had implications for CBD and CCD. Because decisions constitute a multiplicity of activities, the responses by local communities could be related to the potential role played by each indicator in the implementation of the convention at the local level. Copyright © 2007 John Wiley & Sons, Ltd.
Contests with investment
Authors: Münster Johannes 
Published: June 2007

AbstractPerfectly discriminating contests (all pay auctions) are widely used as a model of situations where individuals devote resources to win some prize. In reality such contests are often preceded by investments of the contestants into their ability to fight in the contest. This paper studies a two stage game where in the first stage, players can invest to lower their bid cost in a perfectly discriminating contest, which is played in the second stage. Different assumptions on the timing of investment are studied. With simultaneous investments, equilibria in which players play a pure strategy in the investment stage are asymmetric, exhibit incomplete rent dissipation, and expected effort is reduced relative to the game without investment. There also are symmetric mixed strategy equilibria with complete rent dissipation. With sequential investment, the first mover always invests enough to deter the second mover from investing, and enjoys a first mover advantage. I also look at unobservable investments and endogenous timing of investments. Copyright © 2007 John Wiley & Sons, Ltd.
Can the combination of flaxseed and its lignans with soy and its isoflavones reduce the growth stimulatory effect of soy and its isoflavones on established breast cancer?
Authors: Power Krista A. , Thompson Lilian U. 
Published: June 2007

AbstractConsumption of phytoestrogen (PE)‐rich foods (i. e., soy and flaxseed (FS)) is increasing because of their suggested health benefits. However, recent studies raise concern over the safety of soy and its isoflavones, particularly genistein (GEN), for postmenopausal breast cancer (BC), due to their potential stimulatory effects on human breast tissue and on the growth of existing tumors in rodents. FS, rich in PE lignans, which is metabolized to the mammalian lignans enterolactone (ENL) and enterodiol (END), has consistently been shown to have tumor inhibitory effects in a human clinical trial as well as rodent BC models. Using the preclinical athymic mouse postmenopausal BC model, combining FS with soy protein or GEN with END and ENL, was found to negate the tumor stimulatory effects of soy protein or GEN alone. The mechanism may be related to the modulation of estrogen receptor and MAPK signaling pathways. If these studies can be confirmed in clinical trials, then consumption of combined soy and FS, or their PEs, may reduce the tumor growth stimulatory effect of soy or GEN. This may indicate that if soy is consumed with lignan‐rich foods, it may continue to induce its other beneficial health effects, without inducing adverse effect on postmenopausal BC.
Binding of the hop (Humulus lupulus L.) chalcone xanthohumol to cytosolic proteins in Caco‐2 intestinal epithelial cells
Authors: Pang Yan , Nikolic Dejan , Zhu Dongwei , Chadwick Lucas R. , Pauli Guido F. , Farnsworth Norman R. , van Breemen Richard B. 
Published: June 2007

AbstractUsed in the brewing of beer, hops (Humulus lupulus L.) contain the prenylated chalcone xanthohumol, which is under investigation as a cancer chemoprevention agent and as a precursor for the estrogenic flavanones isoxanthohumol and 8‐prenylnaringenin. The uptake, transport and accumulation of xanthohumol were studied using the human intestinal epithelial cell line Caco‐2 to help understand the poor bioavailability of this chalcone. Studies were carried out using Caco‐2 cell monolayers 18–21 days after seeding. The apparent Km and Vmax values of xanthohumol accumulation in Caco‐2 cells were determined, and the protein binding of xanthohumol in sub‐cellular fractions of Caco‐2 cells was investigated. Approximately 70% of xanthohumol added to the apical side of Caco‐2 cells accumulated inside the cells, while 93% of the intracellular xanthohumol was localized in the cytosol. Xanthohumol accumulation was temperature dependent and saturable with an apparent Km value of 26.5 ± 4.66 μM and an apparent Vmax of 0.215 ± 0.018 nmol/mg protein/min. Facilitated transport was not responsible for the uptake of xanthohumol, instead, accumulation inside the Caco‐2 cells was apparently the result of specific binding to cytosolic proteins. These data suggest that specific binding of xanthohumol to cytosolic proteins in intestinal epithelial cells contributes to the poor oral bioavailability observed previously in vivo.
Metabolism of dietary soy isoflavones to equol by human intestinal microflora – implications for health
Authors: Yuan Jian‐Ping , Wang Jiang‐Hai , Liu Xin 
Published: June 2007

AbstractSoy isoflavones have received considerable attention. Individuals with isoflavones‐rich diets have significantly lower occurrences of cardiovascular disease, osteoporosis, and some cancers. The clinical effectiveness of soy isoflavones may be a function of the ability to biotransform soy isoflavones to the more potent estrogenic metabolite, equol, which may enhance the actions of soy isoflavones, owing to its greater affinity for estrogen receptors, unique antiandrogenic properties, and superior antioxidant activity. However, not all individuals consuming daidzein produce equol. Only approximately one‐third to one‐half of the population is able to metabolize daidzein to equol. This high variability in equol production is presumably attributable to interindividual differences in the composition of the intestinal microflora, which may play an important role in the mechanisms of action of isoflavones. But, the specific bacterial species in the colon involved in the production of equol are yet to be discovered. Therefore, future researches are aimed at identifying the specific bacterial species and strains that are capable of converting daidzein to equol or increasing equol production.
Numerical simulation of three‐dimensional polymer extrusion flow with differential viscoelastic model
Authors: Mu Yue , Zhao Guoqun , Qin Shengxue , Chen Anbiao 
Published: June 2007

AbstractThe numerical simulation of viscoelastic flow problems is nowadays an effective way of investigating the complex flow mechanism related to practical engineering problems, such as plastic injection, blow molding and extrusion. The mathematical model of a three‐dimensional (3D) viscoelastic flow in a typical contraction die for polymer extrusion is established and a stable solving method is investigated. The penalty finite element method (FEM) is performed to simulate the viscoelastic melts flow in the channel with a differential constitutive model. The discrete elastic‐viscous split stress (DEVSS) formulation and the streamline‐upwind Petrov–Galerkin (SUPG) technology are employed to improve the computation stability. Both the implementation of the numerical scheme and its application in the practical process analysis are investigated. The effects of various calculation control parameters and different material parameters upon the numerical results are discussed. The 3D flow patterns in the extrusion die with different contraction angles are further investigated based on the above discussions. Copyright © 2007 John Wiley & Sons, Ltd.