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Simple Regression Analysis (simple + regression_analysis)
Selected AbstractsSolvent effect on the reactivity of CIS -platinum (II) complexes: A density functional approachINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 8 2008Pubalee Sarmah Abstract The structure and chemical reactivity of some selected cis -platinum(II) complexes, including clinically used drug molecules, cisplatin, carboplatin, and oxaliplatin are investigated using density functional theory (DFT) calculations. Calculated geometries of the complexes are in agreement with their available X-ray data. The global and local reactivity descriptors, such as hardness, chemical potential, electrophilicity index, Fukui function, and local philicity are calculated to investigate the usefulness of these descriptors for understanding the reactive nature and reactive sites of the complexes. Inclusion of solvent effect shows that both global and local descriptors change the trend of reactivity with respect to their trend in the gas phase. The stability of the complexes increases with the inclusion of water molecules. Simple regression analysis is applied to build up a quantitative structure-activity relationship (QSAR) model based on DFT derived electrophilicity index for the Pt(II) complexes against A2780 human ovarian adenocarcinoma cell line to establish the importance of the descriptor in predicting cytotoxicity. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Upregulation of Interleukin-8 by Hypoxia in Human OvariesAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2003Osamu Yoshino Problem: To evaluate the effect of hypoxia on interleukin (IL)-8 expression in human ovarian follicles. Method of study: Follicular fluid (FF) from each follicle was separately collected from women undergoing in vitro fertilization and embryo transfer. Concentrations of oxygen, progesterone, estradiol, IL-1,/,, IL-8, and tumor necrosis factor (TNF)- , in FF were measured. Isolated granulosa-lutein cells (GLC) from obtained FF were cultured under normoxic or hypoxic conditions, and concentrations of IL-8 in culture media were measured. Results: Simple regression analysis demonstrated a significant negative correlation between the concentrations of IL-8 and oxygen in FF (r = 0.50, P < 0.0001). However, none of the concentrations of progesterone, estradiol, IL-1,, and TNF- , in FF showed a significant correlation with IL-8 concentrations. Hypoxia stimulated the secretion of IL-8 by cultured GLC over twofolds compared with a normoxic control (P < 0.05). Conclusions: These findings suggest that IL-8, like other angiogenic factors, is upregulated under hypoxic condition, which argues that hypoxia in the ovarian follicles comes into play in ovarian functions by inducing a range of proangiogenic and chemoattractive substances. [source] Chinese Consumers' Attitudes Toward U.S.- and PRC-Made Clothing: From a Cultural PerspectiveFAMILY & CONSUMER SCIENCES RESEARCH JOURNAL, Issue 1 2002Dong Shen To investigate the role of acculturation variables (Western behavioral adoption, adherence to traditional values) in explaining Chinese consumers' attitudes toward U.S.-made and PRC-made clothing, 3,000 consumers from large Chinese cities were surveyed. Responses were received from 870 men and 999 women. Results of a paired sample t test revealed that Chinese consumers' attitudes toward U.S.-made clothing were more favorable than attitudes toward PRC-made clothing. In addition, results of simple regression analyses revealed a positive relationship between attitudes toward U.S.-made clothing and Western behavioral adoption and a negative relationship between attitudes toward PRC-made clothing and Western behavioral adoption. In a related way, simple regression analyses revealed a negative relationship between attitudes toward U.S.-made clothing and degree of adherence to traditional Chinese values and a positive relationship between attitudes toward PRC-made clothing and degree of adherence to traditional values. Implications and ideas for future research are also addressed. [source] Climate,growth relationships of tropical tree species in West Africa and their potential for climate reconstructionGLOBAL CHANGE BIOLOGY, Issue 7 2006JOCHEN SCHÖNGART Abstract Most tropical regions are facing historical difficulties of generating biologically reconstructed long-term climate records. Dendrochronology (tree-ring studies) is a powerful tool to develop high-resolution and exactly dated proxies for climate reconstruction. Owing to the seasonal variation in rainfall we expected the formation of annual tree rings in the wood of tropical West African tree species. In the central-western part of Benin (upper Ouémé catchment, UOC) and in northeastern Ivory Coast (Comoé National Park, CNP) we investigated the relationship between climate (precipitation, sea surface temperature (SST)) and tree rings and show their potential for climate reconstruction. Wood samples of almost 200 trees belonging to six species in the UOC and CNP served to develop climate-sensitive ring-width chronologies using standard dendrochronological techniques. The relationship between local precipitation, monthly SST anomalies in the Gulf of Guinea, El Niño- Southern Oscillation (ENSO) and ring-width indices was performed by simple regression analyses, two sample tests and cross-spectral analysis. A low-pass filter was used to highlight the decadal variability in rainfall of the UOC site. All tree species showed significant relationships with annual precipitation proving the existence of annual tree rings. ENSO signals could not be detected in the ring-width patterns. For legume tree species at the UOC site significant relationships could be found between SST anomalies in the Gulf of Guinea indicating correlations at periods of 5.1,4.1 and 2.3 years. Our findings accurately show the relationship between tree growth, local precipitation and SST anomalies in the Gulf of Guinea possibly associated with worldwide SST patterns. A master chronology enabled the reconstruction of the annual precipitation in the UOC to the year 1840. Time series analysis suggest increasing arid conditions during the last 160 years which may have large impacts on the hydrological cycles and consequently on the ecosystem dynamics and the development of socio-economic cultures and sectors in the Guinea-Congolian/Sudanian region. [source] Evolution of available lysine and furosine contents in milk-based infant formulas throughout the shelf-life storage periodJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2003Emilia Ferrer Abstract The evolution of the Maillard reaction (MR) by measuring the available lysine and furosine (FUR) contents in adapted and follow-up powdered milk-based infant formulas over the shelf-life storage period, at 20 and 37 °C, was studied. Available lysine and FUR contents were determined by fluorimetry and high-performance liquid chromatography respectively. Statistically significant differences were found between adapted and follow-up infant formulas with respect to the available lysine and FUR contents. Available lysine contents decreased significantly throughout the storage time, and the contents at 37 °C were lower than at 20 °C. A statistically significant increase in FUR contents was observed during the storage period, with the contents being high at 37 °C than at 20 °C. A simple regression analysis between the available lysine and FUR contents during (a) the first year (b) the second year and (c) the two storage years was applied. The best correlations were obtained during the first year of storage. The results obtained show a clear MR evolution during the storage of infant formulas. Copyright © 2003 Society of Chemical Industry [source] Relationship Between Global Myocardial Index and Automatic Left Ventricular Border Detection Pattern to Identify Biventricular Pacing CandidatesPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2007DRAGOS COZMA M.D., Ph.D. Objective of the Study: to evaluate the relation between global myocardial index (GMI) and the pattern of left ventricular (LV) volume curves variation, using automatic border detection (ABD), and their role in assessing LV asynchrony. Methods: We studied 52 patients (mean age = 55 ± 17 years) with dilated cardiomyopathy. QRS duration (QRSd) and GMI were measured. Currently accepted TDI and M-mode parameters were used to indicate LV dyssynchrony. On-line continuous LV volume changes were recorded using ABD. Ejection time (ET ABD) was measured from the ABD wave-forms as time interval between maximal and minimal volume variation during LV electromechanical systole. We derived the ejection time index (ETiABD) as the ratio between ET ABD and RR interval (ETiABD = ET/RR). Results: 31 patients had a QRSd >120 ms and 21 patients had a QRSd <120 ms. Ventricular dyssynchrony was observed in 39 patients (29 patients had a QRSd > 120 ms). GMI was significantly higher in patients with, than in patients without ventricular dyssynchrony (1.06 ± 0.18 vs 0.73 ± 0.13, P = 0.0001), while ETABD was significantly smaller (233 ± 39 ms vs 321 ± 28 ms, P = 0.0001). The corresponding difference for ETiABD was 26.9 ± 6.8% vs 6.3 ± 4%, P < 0.0001. By simple regression analysis an inverse linear correlation was observed between GMI and ETiABD (r2=,0.51, P < 0.0001). The pattern of ABD waveforms showed increased isovolumic contraction and relaxation times in patients with LV asynchrony, similar to the GMI pattern. Conclusions: Regional delays in ventricular activation cause uncoordinated and prolonged ventricular contractions, with lengthening of the isovolumic contraction and relaxation times and shortening of the time available for filling and ejection. GMI explores these parameters and together with ABD might be useful to identify patients with ventricular asynchrony. [source] Molecular diversity and association of SSR markers to rust and late leaf spot resistance in cultivated groundnut (Arachis hypogaea L.)PLANT BREEDING, Issue 1 2010S. Mondal With 1 figure and 2 tables Abstract Molecular diversity and association of simple sequence repeat (SSR) markers with rust and late leaf spot (LLS) resistance were detected in a set of 20 cultivated groundnut genotypes differing in resistance against both diseases. Out of 136 bands amplified from 26 primers, 104 were found polymorphic (76.5%). Cluster analysis (UPGMA) revealed two main clusters separated at 52% Jaccard's similarity coefficient according to disease reaction to rust and LLS. Based on the Kruskal,Wallis one-way anova and simple regression analysis three and four SSR alleles were found associated with rust and LLS resistance, respectively. [source] | ||||||||||||||||