bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen and phosphorus levels in the Yazoo River Basin, Mississippi
Authors: Shields F. Douglas , Testa Sam , Cooper Charles M. 
Published: February 2009

AbstractNitrogen (N) and phosphorus (P) loadings to aquatic ecosystems are linked to environmental problems such as hypoxia. Presented is an assessment of accessible data on nutrient sources, sinks and inputs to streams within the Yazoo River Basin of northern Mississippi. Spatial trends were examined by plotting the temporal mean and median concentration for each site versus contributing drainage area, and seasonal patterns were examined by comparing monthly mean and median concentrations computed across a range of sites. Mean total N values were computed for 75 sites with periods of record ranging from 3·3 to 28·6 years. The global mean (mean of site means) total N concentration for the Delta was 3·3 mg l−1 but only 1·2 mg l−1 for the Hills, and both were about two to four times higher than US Environmental Protection Agency (US EPA) criteria for each of these ecoregions. Total P data were found for 122 sites with periods of record ranging from 3·2 to 28·6 years. Delta mean N and P concentrations were inversely proportional to contributing drainage area, while those of Hill sites were not. The Hill mean P concentration was 0·15 mg l−1, while the mean for Delta sites was more than four times greater, 0·66 mg l−1. These values are about four to five times the levels set as criteria by the US EPA. Delta N and P concentrations peak strongly in spring when agricultural fertilizers are applied and stream flows are highest. Concentrations of N in Hill streams do not exhibit seasonal patterns, but mean monthly P levels are correlated with mean monthly discharge. Copyright © 2009 John Wiley & Sons, Ltd.
G‐Quadruplex DNA Structures and Organic Chemistry: More Than One Connection
Authors: Franceschin Marco 
Published: February 2009

AbstractG‐Quadruplexes represent a group of unusual DNA secondary structures, based on Hoogsteen G–G paired hydrophobic planar rings consisting of four guanine units. Many studies have shown that G‐quadruplex structures appear to be involved in several important biological processes, such as DNA replication, gene expression and recombination, as well as cell transformation. For these reasons, in the last few years G‐quadruplexes have become the main research interest of many eminent scientists in different fields: from molecular to cellular biologists, from physicians to chemists. In this respect, organic chemists can play fundamental roles in many different areas. First of all, research into specific G‐quadruplex ligands as potential drugs, in particular as telomerase inhibitors and thus potential anticancer drugs, has attracted strong attention. The rational design of and the various synthetic approaches toward these kinds of ligands represent two specific fields of interest for organic chemists. The molecules capable of stabilizing G‐quadruplexes covered in this review are each characterized by an aromatic core that favours stacking interactions with the G‐tetrads and, in most cases, by basic side chains that interact with DNA grooves. First generations and new classes of synthetic G‐quadruplex ligands, as well as natural compounds, are presented. Moreover, because the specificities of the interactions between the studied ligands and different DNA structures (both duplex and quadruplex) are without doubt a main concern, determining the different biological effects of these compounds, several chemists are involved in developing approaches to explore this important subject. The last part of this review is devoted to a brief introduction of new fields of application of G‐quadruplex structures with open synthetic challenges: quadruplex‐forming modified oligonucleotides and nanostructures based on the G‐quadruplex.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Hirsch‐Type Index Values for Organic Chemistry Journals: A Comparison of New Metrics with the Journal Impact Factor
Authors: Bornmann Lutz , Marx Werner , Schier Hermann 
Published: February 2009

AbstractIn August 2005, Jorge Hirsch introduced with the h index a new research performance indicator. His index is an original and simple new measure that incorporates both quantity and visibility of publications. Since 2005, a number of corrections and complementary indices to the h index as well as single‐number alternatives have already been put forward. We examine in the present study the h index and the most important h index variants that have been proposed and discussed in the literature. The aim of the analysis is to determine empirically the extent to which the usage of the h index and its variants for measuring the performance of journals results in an incremental contribution against the Journal Impact Factor (JIF). JIF, h index, and different variants of the h index were calculated for 20 organic chemistry journals. As the findings reveal high intercorrelations, the different performance measures could be called redundant in empirical application. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Three structurally homologous isothiocyanates exert “Janus” characteristics in human HepG2 cells
Authors: Lamy Evelyn , Crößmann Catharina , Saeed Adal , Schreiner Peter R. , Kotke Mike , Mersch‐Sundermann Volker 
Published: February 2009

AbstractIn this study, we used the single cell gel electrophoresis (SCGE) assay and the micronucleus (MN) test to investigate the DNA damaging effects and the antigenotoxic potencies of three structurally related ITCs in human HepG2 cells. The results show that all three ITCs possess the characteristic of a “Janus” compound, i.e., they exert both significant genotoxicity and antigenotoxicity, depending on the concentrations used in the test systems applied. Regression line analysis of the results derived by SCGE analysis showed genotoxic potency of the ITCs in the following order: 3‐methylthiopropyl ITC (MTPITC) > 4‐methylthiobutyl ITC (MTBITC) > 5‐methylthiopentyl ITC (MTPeITC); however, this order in genotoxic potency was not confirmed by MN analysis. Additionally, the MN test showed significant mutagenicity of the test substances at higher concentrations when compared with the SCGE assay. Twenty‐four hour‐treatment of the cells with the ITCs, followed by a 1‐hr recovery period, showed significant DNA repair in the SCGE assay at a concentration ≥10 μM MTPITC, ≥3 μM MTBITC, and ≥0.1 μM MTPeITC, respectively. In antigenotoxicity studies, the most effective concentration of MTPITC and MTPeITC toward B(a)P‐induced DNA damage was 0.1 μM in both test systems. MTBITC suppressed MN formation in B(a)P‐treated cells to the background level at a concentration of 1 μM. The ambivalent character of the ITCs under studymust be further clarified, especially in the possiblecontext of high dose therapeutic applications. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.
Biological properties of garlic and garlic‐derived organosulfur compounds
Authors: Iciek Małgorzata , Kwiecień Inga , Włodek Lidia 
Published: February 2009

AbstractMedicinal properties of garlic (Allium sativum) have been widely known and used since ancient times till the present. Garlic enhances immune functions and has antibacterial, antifungal and antivirus activities. It is known to prevent platelet aggregation, and to have hypotensive and cholesterol‐ and triglyceride‐lowering properties, although the latter features have been questioned. This review is focused on anticancer efficacy of Allium sativum, and attempts to explain the mechanisms of this action. Medicinal properties of garlic rely upon organosulfur compounds mostly derived from alliin. Organosulfur compounds originating from garlic inhibit carcinogen activation, boost phase 2 detoxifying processes, cause cell cycle arrest mostly in G2/M phase, stimulate the mitochondrial apoptotic pathway, increase acetylation of histones. Garlic‐derived sulfur compounds influence also gap‐junctional intercellular communication and participate in the development of multidrug resistance. This review presents also other little known aspects of molecular action of garlic‐derived compounds, like modulation of cellular redox state, involvement in signal transduction and post‐translational modification of proteins by sulfane sulfur or by formation of mixed disulfides (S‐thiolation reactions). Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.
Nuclear powered CO2 capture from the atmosphere
Authors: Sherman Steven R. 
Published: February 2009

AbstractA process for capturing CO2 from the atmosphere was recently proposed. This process uses a closed cycle of sodium and calcium hydroxide, carbonate, and oxide transformations to capture dilute CO2 from the atmosphere and to generate a concentrated stream of CO2 that is amenable to sequestration or subsequent chemical transformations. In one of the process steps, a fossil‐fueled lime kiln is needed, which reduces the net CO2 capture of the process. It is proposed to replace the fossil‐fueled lime kiln with a modified kiln heated by a high‐temperature nuclear reactor. This will have the effect of eliminating the use of fossil fuels for the process and increasing the net CO2 capture. Although the process is suitable to support sequestration, the use of a nuclear power source for the process provides additional capabilities, and the captured CO2 may be combined with nuclear‐produced hydrogen to manufacture liquid fuels via Fischer‐Tropsch synthesis or other technologies. Conceivably, such plants would be carbon‐neutral and could be placed virtually anywhere without being tied to fossil fuel sources or geological sequestration sites. © 2009 American Institute of Chemical Engineers Environ Prog, 2009
Using LCA to enhance EMS: Pulp and paper case study
Authors: Gaudreault Caroline , Samson Réjean , Stuart Paul R. 
Published: February 2009

AbstractLife cycle thinking and life cycle management (LCM) are concepts which have been gaining increasing attention from the industry. However, there is a need for tools and methods to make these concepts operational. Environmental management systems (EMS) and life cycle assessment (LCA) are mature tools that can be used to support the implementation of LCM within organizations. This article proposes a methodology for the integration of these tools. More specifically, it addresses the importance of LCA methodological choices in this context. A pulp and paper case study is used to illustrate the methodology. The potential of using such an integrated framework for assessing the environmental implications of capital investment projects is also underlined. It is concluded that the integration is possible but that conventional EMS evaluation is still required. © 2009 American Institute of Chemical Engineers Environ Prog, 2009
Capital cost prediction for biogas installations in Africa: Lang factor approach
Authors: Amigun B. , von Blottnitz H. 
Published: February 2009

AbstractSub‐Saharan African countries are well‐suited for the biogas digester technology because of their warm climates and availability of animal manure. This technology could serve as a means to overcome energy poverty, which poses a constant barrier to economic development in Africa. A generative type of capital cost estimation based on knowledge of flowsheet and major equipment, which can be used by investors to indicate the magnitude of the proposed investment and help to provide other information, including the profitability of the project, was employed. In this study, three operating, small to medium scale biogas plants and one commercial scale biogas was used to determine the cost structure. Analysis of the breakdown of the fixed capital investment (FCI) cost, based on the principle of factorial method of capital cost estimation and using Lang factor (fL) analysis was used to create an econometric model for calculating FCI. A Lang factor (fL) value of 2.63, 2.91, and 3.04 has been obtained for small/medium scale biogas plants in two African locations. Calibration of the factors revealed that fL value of 2.63 gives a better cost prediction. The verification of the correctness of the performance model also revealed that the model satisfies all the three Conte's criteria indicating that the model is sufficient for the purpose of effort estimation. An estimated fL value of 1.79 was obtained for the large scale biogas plant. © 2009 American Institute of Chemical Engineers Environ Prog, 2009
Seasonal soil aggregate stability variation in relation to rainfall and temperature under Mediterranean conditions
Authors: Dimoyiannis D. 
Published: February 2009

AbstractAggregate stability, one of the main factors controlling soil erodibility, varies over time. Knowledge of its variation would help to identify better soil management practices. In 10 soils from central Greece devoted to cereal cropping, seasonal wet aggregate stability (WAS) fluctuations were investigated over a period of two successive years. The wet‐sieving technique of air‐dried aggregates was used for WAS determinations, according to a test resulting in an instability index calculation. Over the first year, when typical Mediterranean climatic conditions dominated, WAS varied according to a nearly cyclic pattern, from a low in winter or early‐spring months to a high in summer months. The instability index varied from a high between 123–152% of annual average to a low between 58–83% of annual average. Total monthly rainfall (TR) and mean monthly air temperature (MAT) strongly correlated with seasonal WAS. Their ratio (TR/MAT, ombrothermic ratio) has been proved to be a good predictor of structural stability throughout the year, for most of the soils studied. Possible mechanisms deteriorating aggregation seemed to be raindrop impact, repeated soil drying and wetting and repeated soil freezing and thawing, while possible mechanisms promoting aggregation seemed to be soil drying and warming and biological activity. Over the second year, severe climatic inconsistencies complicated the seasonal pattern of WAS response. From January to March, WAS unexpectedly increased, obtaining its maximum value for most of the soils in March, then it varied inconsistently until October and thereafter decreased, obtaining its minimum value in December for all soils. The instability index varied from a high between 130–196% of annual average to a low between 61–83% of annual average. Uneven seasonal distribution of climatic characteristics and extreme events decisively modified the typical for Mediterranean conditions seasonal WAS variation pattern. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of the Ripple Current in a 5 kW Polymer Electrolyte Membrane Fuel Cell Stack
Authors: Ladewig B. P. , Lapicque F. 
Published: February 2009

AbstractPolymer electrolyte fuel cell systems are increasingly being used in applications requiring an inverter to convert the direct current (DC) output of the stack to an alternating current (AC). These inverters, and other time‐varying inputs to the stack such as the anode feed pressure, cause deviations from the average stack current, or ripple currents, which are undesirable for reasons of performance and durability. A dynamic fuel cell model has been developed and validated against experimental data for a 5 kW fuel cell stack, examining in detail the ripple current behaviour. It was shown that the ripple currents exceed the 2% maximum recommended value, and may lead to long‐term degradation of the fuel cell stack.
Pyridoxal‐5′‐phosphate phosphatase/chronophin inhibits long‐term potentiation induction in the rat dentate gyrus
Authors: Kim Ji‐Eun , Kim Dae‐Won , Kwak Sung‐Eun , Ryu Hea Jin , Yeo Seong‐Il , Kwon Oh‐Shin , Choi Soo‐Young , Kang Tae‐Cheon 
Published: February 2009

AbstractPyridoxal‐5′‐phosphate (PLP)‐phosphatase/chronophin (PLPP/CIN) directly dephosphorylates actin‐depolymerizing factor (ADF)/cofilin as well as PLP. Although PLPP/CIN plays a role in the regulation of F‐actin and vitamin B6metabolism, there is no direct evidence to support a correlation between PLPP/CIN and F‐actin polymerization during long‐term potentiation (LTP) induction. In this study, we investigated whether the expression of PLPP/CIN is altered following LTP induction, and whether Tat‐PLPP/CIN transduction affects LTP induction in the rat dentate gyrus (DG). PLPP/CIN immunoreactivity was markedly decreased in dentate granule cells after the induction of LTP. Tat‐PLPP/CIN transduction (20 and 200 μg/kg) decreased the efficiency of high frequency stimulus‐induced potentiation of populations spike amplitude as compared to saline or Tat‐protein‐treated animals. The PLPP/CIN protein level showed an inverse correlation with phosphorylated ADF/cofilin levels and F‐actin content. These findings suggest that PLPP/CIN‐mediated actin dynamics may play an important role in the changes of morphological properties (dendritic spine reorganization) of the hippocampus in LTP. © 2009 Wiley‐Liss, Inc.
Genistein depletes telomerase activity through cross‐talk between genetic and epigenetic mechanisms
Authors: Li Yuanyuan , Liu Liang , Andrews Lucy G. , Tollefsbol Trygve O. 
Published: February 2009

AbstractGenistein, a natural isoflavone found in soybean products, has been reported to down‐regulate telomerase activity and that this prevents cancer and contributes to the apoptosis of cancer cells. However, the precise molecular mechanism by which genistein represses telomerase is not clear. Here, we show that genistein inhibits the transcription of hTERT (human telomerase reverse transcriptase), the catalytic subunit of the human telomerase enzyme, in breast MCF10AT benign cells and MCF‐7 cancer cells in a time‐ and dose‐dependent manner. Three major DNA methyltransferases (DNMT1, 3a and 3b) were also decreased in genistein‐treated breast cancer cells suggesting that genistein may repress hTERT by impacting epigenetic pathways. Sequential depletion of the hTERT promoter revealed that the hTERT core promoter region is responsible for the genistein‐induced repression of hTERT transcription. Using a newly developed technique of chromatin immunoprecipitation (ChIP)‐related bifulfite sequencing analysis, we found an increased binding of E2F‐1 to the hTERT promoter is due to the site‐specific hypomethylation of the E2F‐1 recognition site. In addition, we found that genistein can remodel chromatin structures of the hTERT promoter by increasing trimethyl‐H3K9 but decreasing dimethyl‐H3K4 in the hTERT promoter. The repression of hTERT was enhanced by combination with genistein and the DNMT inhibitor, 5‐aza‐2′‐deoxycytidine (5‐aza‐dCyd). These findings collectively show that genistein is working, at least in part, through epigenetic mechanisms of telomerase inhibition in breast benign and cancer cells and may facilitate approaches to breast cancer prevention and treatment using an epigenetic modulator combined with genistein. © 2009 UICC
Interferon‐γ reverses the immunosuppressive and protumoral properties and prevents the generation of human tumor‐associated macrophages
Authors: Duluc Dorothée , Corvaisier Murielle , Blanchard Simon , Catala Laurent , Descamps Philippe , Gamelin Erick , Ponsoda Stéphane , Delneste Yves , Hebbar Mohamed , Jeannin Pascale 
Published: February 2009

AbstractTumor‐associated macrophages (TAM) are M2d‐polarized cells (IL‐10high, IL‐12low, ILT3high, CD86low) that accumulate in tumor microenvironment. TAM inhibit antitumor T lymphocyte generation and function, contribute to tumor tolerance and are trophic for tumors. In this study, we investigated whether some immunological factors may reverse TAM immunosuppressive properties. Among 32 cytokines, we have identified IFNγ on its ability to switch immunosuppressive TAM into immunostimulatory cells. Upon IFNγ exposure, TAM purified from ovarian cancer ascites recover a M1 phenotype (IL‐10low, IL‐12high), express high levels of CD86 and low levels of ILT3, enhance the proliferation of CD4+ T lymphocytes and potentiate the cytotoxic properties of a MelanA‐specific CD8+ T cell clone. IFNγ‐treated TAM also secreted reduced levels of mediators promoting suppressive T cell accumulation (CCL18) and trophic for tumors (VEGF and MMP9). As TAM derive from the local differentiation of peripheral blood monocytes, we investigated whether IFNγ may also affect TAM generation. In the presence of ovarian ascites, IFNγ skewed monocyte differentiation from TAM‐like cells to M1‐polarized immunostimulatory macrophages. Together, these data show that IFNγ overcomes TAM‐induced immunosuppression by preventing TAM generation and functions. These data highlight that IFNγ used locally at the tumor site could potentiate the efficacy of antitumor immunotherapies based on the generation of effector T cells. © 2009 UICC
The induction of autophagy by γ‐radiation contributes to the radioresistance of glioma stem cells
Authors: Lomonaco Stephanie L. , Finniss Susan , Xiang Cunli , DeCarvalho Ana , Umansky Felix , Kalkanis Steven N. , Mikkelsen Tom , Brodie Chaya 
Published: February 2009

AbstractMalignant gliomas are characterized by a short median survival which is largely impacted by the resistance of these tumors tochemo‐ and radiotherapy. Recent studies suggest that a small subpopulation of cancer stem cells, which are highly resistant to γ‐radiation, has the capacity to repopulate the tumors and contribute to their malignant progression. γ‐radiation activates the process of autophagy and inhibition of this process increases the radiosensitivity of glioma cells; however, the role of autophagy in the resistance of glioma stem cells (GSCs) to radiation has not been yet reported. In this study we examined the induction of autophagy by γ‐radiation in CD133+ GSCs. Irradiation of CD133+ cells induced autophagy within 24–48 hr and slightly decreased the viability of the cells. γ‐radiation induced a larger degree of autophagy in the CD133+ cells as compared with CD133− cells and the CD133+ cells expressed higher levels of the autophagy‐related proteins LC3, ATG5 and ATG12. The autophagy inhibitor bafilomycin A1 and silencing of ATG5 and beclin1 sensitized the CD133+ cells to γ‐radiation and significantly decreased the viability of the irradiated cells and their ability to form neurospheres. Collectively, these results indicate that the induction of autophagy contributes to the radioresistance of these cells and autophagy inhibitors may be employed to increase the sensitivity of CD133+ GSCs to γ‐radiation. © 2009 UICC