bluuebunny/crossref_metadata_2025_split huggingface dataset:
The use of Cu and Zn salicylaldimine complexes as catalyst precursors in ring opening polymerization of lactides: ligand effects on polymer characteristics
Authors: Bhunora Suraj , Mugo Jane , Bhaw‐Luximon Archana , Mapolie Selwyn , Van Wyk Juanita , Darkwa James , Nordlander Ebbe 
Published: November 2010

AbstractA range of monomeric tetra‐coordinate copper (II) and zinc (II) complexes based on N,O‐bidentate salicylaldimine Schiff base ligands has been synthesized and characterized using various spectroscopic techniques. These complexes were then evaluated as initiators in ring‐opening polymerization of lactides at both 70 °C and 110 °C. The effect of structural changes in the complexes on the ability of these compounds to initiate lactide polymerization as well as the impact on the chemical and physical characteristics of the polymers obtained indicate that the coordination geometry of the metal complex, MO bond length and substituents on the Schiff base ligand all play a role in the catalyst activity. Electronic factors were dominant in the case of the copper complexes while steric factors prevailed in the case of Zn initiators. Both the Zn and Cu complexes exhibit characteristics of living ring opening polymerization. Copyright © 2010 John Wiley & Sons, Ltd.
The Action Sites of Propofol in the Normal Human Brain Revealed by Functional Magnetic Resonance Imaging
Authors: Zhang Hui , Wang Wei , Zhao Zhijing , Ge Yali , Zhang Jinsong , Yu Daihua , Chai Wei , Wu Shengxi , Xu Lixian 
Published: November 2010

AbstractPropofol has been used for many years but its functional target in the intact brain remains unclear. In the present study, we used functional magnetic resonance imaging to demonstrate blood oxygen level dependence signal changes in the normal human brain during propofol anesthesia and explored the possible action targets of propofol. Ten healthy subjects were enrolled in two experimental sessions. In session 1, the Observer's Assessment of Alertness/Sedation Scale was performed to evaluate asleep to awake/alert status. In session 2, images with blood oxygen level dependence contrast were obtained with echo‐planar imaging on a 1.5‐T Philips Gyroscan Magnetic Resonance System and analyzed. In both sessions, subjects were intravenously administered with saline (for 3 min) and then propofol (for 1.5 min) and saline again (for 10.5 min) with a constant speed infusion pump. Observer's Assessment of Alertness/Sedation Scale scoring showed that the subjects experienced conscious–sedative–unconscious–analepsia, which correlated well with the signal decreases in the anesthesia states. Propofol induced significant signal decreases in hypothalamus (18.2% ± 3.6%), frontal lobe (68.5% ± 11.2%), and temporal lobe (34.7% ± 6.1%). Additionally, the signals at these three sites were fulminant and changed synchronously. While in the thalamus, the signal decrease was observed in 5 of 10 of the subjects and the magnitude of decrease was 3.9% ± 1.6%. These results suggest that there is most significant inhibition in hypothalamus, frontal lobe, and temporal in propofol anesthesia and moderate inhibition in thalamus. These brain regions might be the targets of propofol anesthesia in human brain. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.
Characterization of combinatorial patterns generated by multiple two‐component sensors in E. coli that respond to many stimuli
Authors: Clarke Elizabeth J. , Voigt Christopher A. 
Published: November 2010

AbstractTwo‐component systems enable bacteria to sense changes in their environment and adjust gene expression in response. Multiple two‐component systems could function as a combinatorial sensor to discriminate environmental conditions. A combinatorial sensor is composed of a set of sensors that are non‐specifically activated to different magnitudes by many stimuli, such that their collective activity pattern defines the signal. Using promoter reporters and flow cytometry, we measured the response of three two‐component systems in Escherichia coli that have been previously reported to respond to many environmental stimuli (EnvZ/OmpR, CpxA/CpxR, and RcsC/RcsD/RcsB). A chemical library was screened for the ability to activate the sensors and 13 inducers were identified that produce different patterns of sensor activity. The activities of the three systems are uncorrelated with each other and the osmolarity of the inducing media. Five of the seven possible non‐trivial patterns generated by three sensors are observed. This data demonstrate one mechanism by which bacteria are able to use a limited set of sensors to identify a diverse set of compounds and environmental conditions. Biotechnol. Bioeng. 2011; 108:666–675. © 2010 Wiley Periodicals, Inc.
Inhibition and gene expression of Nitrosomonas europaea biofilms exposed to phenol and toluene
Authors: Lauchnor Ellen G. , Radniecki Tyler S. , Semprini Lewis 
Published: November 2010

AbstractPure culture biofilms of the ammonia‐oxidizing bacterium Nitrosomonas europaea were grown in a Drip Flow Biofilm Reactor and exposed to the aromatic hydrocarbons phenol and toluene. Ammonia oxidation rates, as measured by nitrite production in the biofilms, were inhibited 50% when exposed to 56 µM phenol or 100 µM toluene, while 50% inhibition of suspended cells occurred at 8 µM phenol or 20 µM toluene. Biofilm‐grown cells dispersed into liquid medium and immediately exposed to phenol or toluene experienced similar inhibition levels as batch grown cells, indicating that mass transfer may be a factor in N. europaea biofilm resistance. Whole genome microarray analysis of gene expression was used to detect genes up‐regulated in biofilms during toluene and phenol exposure. Two genes, a putative pirin protein (NE1545) and a putative inner membrane protein (NE1546) were up‐regulated during phenol exposure, but no genes were up‐regulated during toluene exposure. Using qRT‐PCR, up‐regulation of NE1545 was detected in biofilms and suspended cells exposed to a range of phenol concentrations and levels of inhibition. In the biofilms, NE1545 expression was up‐regulated an average of 13‐fold over the range of phenol concentrations tested, and was essentially independent of phenol concentration. However, the expression of NE1545 in suspended cells increased from 20‐fold at 7 µM phenol up to 80‐fold at 30 µM phenol. This study demonstrates that biofilms of N. europaea are more resistant than suspended cells to inhibition of ammonia oxidation by phenol and toluene, even though the global transcriptional responses to the inhibitors do not differ in N. europaea between the suspended and attached growth states. Biotechnol. Bioeng. 2011; 108:750–757. © 2010 Wiley Periodicals, Inc.
A Kinetic Model for Simultaneous Saccharification and Fermentation of Avicel With Saccharomyces cerevisiae
Authors: van Zyl Josebus M. , van Rensburg Eugéne , van Zyl Willem H. , Harms Thomas M. , Lynd Lee R. 
Published: November 2010

AbstractThis work describes a numerical model for predicting simultaneous saccharification and fermentation of Avicel, an insoluble crystalline cellulose polymer. Separate anoxic cultivations of 40 g/L glucose and 100 g/L Avicel were conducted to verify model predictions and obtain parameters to describe the reaction kinetics. Saccharification of Avicel was achieved with Trichoderma reesei cellulases from the enzyme preparation Spezyme CP with an enzyme loading of 10 FPU/g cellulose. Cultivations were supplemented with 50 IU/g cellulose of β‐glucosidase from Novozym 188 to prevent product inhibition by cellobiose. Saccharomyces cerevisiae MH‐1000 is a robust industrial strain and was used to ferment glucose to ethanol, glycerol, and carbon dioxide. The numerical model presented in this paper differs from previous models by separating the endoglucanase and exoglucanase enzyme kinetics and allowing for inhibitive site competition. Assuming all enzymes remain active and that each enzyme complex has a corresponding constant specific activity, the model is capable of predicting adsorbed enzyme concentrations with reasonable accuracy. Comparison of predicted values to experimental measurements indicated that the numerical model was capable of capturing the significant elements involved with cellulose conversion to ethanol. Biotechnol. Bioeng. 2011; 108:924–933. © 2010 Wiley Periodicals, Inc.
Activity of maize transglutaminase overexpressed in escherichia coli inclusion bodies: An alternative to protein refolding
Authors: Carvajal Patricia , Gibert Jordi , Campos Nefertiti , Lopera Oriol , Barberà Eduard , Torné Jose M. , Santos Mireya 
Published: November 2010

AbstractTransglutaminases (TGases) catalyze protein post‐translational modification by ε‐(γ‐glutamyl) links and covalent polyamine conjugation. In plants, this enzyme is poorly characterized and only the maize plastidial TGase gene (tgz) has been cloned. The tgz gene (Patent WWO03102128) had been subcloned and overexpressed in Escherichia coli cells, and the recombinant protein (TGZp) was present mainly in inclusion bodies (IB) fraction. In this work, after overexpression of TGZ15p and SDS‐PAGE IB fraction analysis, bands about 65 and 56 kDa were obtained. Western blot, alkylation and MALDI‐TOF/TOF analyses indicated that the 56 kDa band corresponded to a truncated sequence from the native TGZ15p (expected MW 65 kDa), by elimination of a chloroplast signal peptide fragment during expression processing. So that large‐scale protein production and protein crystallization can be applied, we characterized the TGZ15p enzyme activity in the IB protein fraction, with and without refolding. Results indicate that it presented the biochemical characteristics of other described TGases, showing a certain plant‐substrate preference. Solubilization of the IB fraction with Triton X‐100 as nondenaturing detergent yielded active TGZ without the need for refolding, giving activity values comparable to those of the refolded protein, indicating that this is a valuable, faster way to obtain TGZ active protein. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
7,8‐Secolignans from Schisandra wilsoniana and Their Anti‐HIV‐1 Activities
Authors: Zhang Xing‐Jie , Yang Guang‐Yu , Wang Rui‐Rui , Pu Jian‐Xin , Sun Han‐Dong , Xiao Wei‐Lie , Zheng Yong‐Tang 
Published: November 2010

AbstractTwo new 7,8‐secolignans, marphenols A and B (1 and 2, resp.), together with a known related derivative, 7,8‐secoholostylone B (3), were isolated from the stems of Schisandra wilsoniana. The structures of 1 and 2 were elucidated by spectroscopic methods, including extensive 1D‐ and 2D‐NMR techniques. The anti‐HIV‐1 activities of 1–3 were evaluated. Compound 1 inhibited HIV‐1IIIB‐induced syncytia formation with an EC50 value of 0.55 μg ml−1. It reduced p24 antigen expression in acutely HIV‐1IIIB‐infected C8166 cells and primary isolate HIV‐1TC‐2‐infected peripheral blood mononuclear cells (PBMCs), with EC50 values of 3.34 and 0.52 μg ml−1, respectively. It showed no effects on the HIV‐1IIIB replication in chronically infected H9 cells as well as fusion inhibition.
New Cytotoxic Prostanoids from Taiwanese Soft CoralClavularia viridis
Authors: Shen Ya‐Ching , Lo Kuang‐Liung , Chang Jiun‐Yang , Lin Yun‐Sheng , Mendbayar Khongorzul , Kuo Yao‐Haur , Lin Yu‐Chi 
Published: November 2010

AbstractChemical investigation of the AcOEt/MeOH extract ofClavularia viridiscollected in Taiwan has afforded four new prostanoids, named claviridins A–D (1–4, resp.). The structures of compounds1–4were determined on the basis of 1D‐ and 2D‐NMR techniques, including COSY, HMQC, HMBC, and NOESY experiments. Pharmacological studies revealed that compounds1–4exhibited potent cytotoxicity against human cancer cells.
Geranium macrorrhizum L. (Geraniaceae) Essential Oil: A Potent Agent Against Bacillus subtilis
Authors: Radulović Niko S. , Dekić Milan S. , Stojanović‐Radić Zorica Z. , Zoranić Suad K. 
Published: November 2010

AbstractThe volatile hydrodistilled compounds from aerial parts and rhizomes of the ethnopharmacologically highly valued plant species Geranium macrorrhizum L. were screened for their antimicrobial activity in disc‐diffusion and microdilution assays. The assays pointed out to a very high and selective activity of the oils against Bacillus subtilis with minimum inhibitory concentrations (MIC) of 0.4–1.0 μg/ml. This prompted us to perform detailed compositional analyses of the oils. GC and GC/MS analyses allowed the identification of 283 constituents. The oils consisted mainly of sesquiterpenoids, the main ones being germacrone (49.7% in the oil from aerial parts) and δ‐guaiene (49.2% in rhizome oil). Significant qualitative and quantitative compositional differences in the oils from the two plant parts were observed. Further antimicrobial testing enabled us to determine that germacrone, the major constituent of the oil from aerial parts, was not the sole agent responsible for the observed activity.
C2‐Symmetric Chiral Disulfoxide Ligands in Rhodium‐Catalyzed 1,4‐Addition: From Ligand Synthesis to the Enantioselection Pathway
Authors: Mariz Ronaldo , Poater Albert , Gatti Michele , Drinkel Emma , Bürgi Justus J. , Luan Xinjun , Blumentritt Sascha , Linden Anthony , Cavallo Luigi , Dorta Reto 
Published: November 2010

AbstractA family of chiral C2‐symmetric disulfoxide ligands possessing biaryl atropisomeric backbones has been synthesized by using the Andersen methodology. Complete characterization includes X‐ray crystallographic studies of all ligands and some of their rhodium complexes. Their synthesis, optical purity, electronic properties, and catalytic behavior in the prototypical rhodium‐catalyzed 1,4‐addition of phenylboronic acid to 2‐cyclohexen‐1‐one are presented through an in depth study of this ligand class. Density functional theory calculations on the step of the catalytic cycle that determines the enantioselectivity are presented and reinforce the first hypothetical explanations for the high levels of asymmetric induction observed.
One‐Pot Synthesis of 1,3,5‐Tribenzoylbenzenes by Three Consecutive Michael Addition Reactions of 1‐Phenyl‐2‐propyn‐1‐ones in Pressurized Hot Water in the Absence of Added Catalysts
Authors: Tanaka Makoto , Nakamura Kazuya , Iwado Tatsuya , Sato Toshiyuki , Okada Masaki , Sue Kiwamu , Iwamura Hiizu , Hiaki Toshihiko 
Published: November 2010

AbstractCyclotrimerization of 1‐phenyl‐2‐propyn‐1‐one in pressurized hot water gave 1,3,5‐tribenzoylbenzene in one pot in 65 % yield after 7 min at 200 °C, or in 74 % yield after 60 min at 150 °C. The reaction did not take place in the absence of water, and added base promoted the reaction at 250 °C, suggesting a mechanism of three‐consecutive Michael addition reactions. The reaction rates increased with temperature, but the yield of 1,3,5‐tribenzoylbenzene decreased at the expense of formation of acetophenone as a side product at higher temperatures. p‐Methyl and p‐chloro‐substituents on the phenyl ring retarded and enhanced the reaction, respectively. A mechanism involving the enol of benzoylacetaldehyde at a branching point of the pathway leading to 1,3,5‐tribenzoylbenzene and acetophenone was suggested.
The effects of functional polysiloxane resins on the color gamut and color yield of dyed polyester
Authors: Hou Aiqin , Chen Bo , Zhang Kai 
Published: November 2010

AbstractIt is important to evaluate the influence of textile finishing using the polymer resins on the color of dyed fabrics. In this article, three functional polysiloxanes modified with different organic groups were used to treat dyed polyester microfiber fabrics. Effects of the polysiloxanes on the color of the dyed polyester were investigated by color yield (K/S), colorimetric data of CIELAB, and the color differences (ΔE). Chemical structures of three functional polysiloxanes were the polysiloxanes with amino groups (polymer A), with perfluorocarbon groups (polymer B), or with quaternary ammonium salts and perfluorocarbon groups (polymer C). Compared with the dyed fabrics treated with the polysiloxane with amino group, the K/S of dyed fabrics treated with the polysiloxane with perfluorocarbon obviously improved. Effects of the polysiloxanes with perfluorocarbon and cationic groups on the color shade of the dyed polyester were noticeable. The fastness had not significantly changed. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2012
Texture affects color emotion
Authors: Lucassen Marcel P. , Gevers Theo , Gijsenij Arjan 
Published: November 2010

AbstractSeveral studies have recorded color emotions in subjects viewing uniform color (UC) samples. We conduct an experiment to measure and model how these color emotions change when texture is added to the color samples. Using a computer monitor, our subjects arrange samples along four scales: warm–cool, masculine–feminine, hard–soft, and heavy–light. Three sample types of increasing visual complexity are used: UC, grayscale textures, and color textures (CTs). To assess the intraobserver variability, the experiment is repeated after 1 week. Our results show that texture fully determines the responses on the Hard‐Soft scale, and plays a role of decreasing weight for the masculine–feminine, heavy–light, and warm–cool scales. Using some 25,000 observer responses, we derive color emotion functions that predict the group‐averaged scale responses from the samples' color and texture parameters. For UC samples, the accuracy of our functions is significantly higher (average R2 = 0.88) than that of previously reported functions applied to our data. The functions derived for CT samples have an accuracy of R2 = 0.80. We conclude that when textured samples are used in color emotion studies, the psychological responses may be strongly affected by texture. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010
Energy Transfer Pathways in a Rylene‐Based Triad
Authors: Fron Eduard , Puhl Larissa , Oesterling Ingo , Li Chen , Müllen Klaus , De Schryver Frans C. , Hofkens Johan , Vosch Tom 
Published: November 2010

AbstractHerein, a study on the excitation energy migration is reported for a newly synthesized Triad with a well‐defined architecture consisting of a central terrylenediimide decorated with four perylenediimide and sixteen naphthalenemonoimide chromophores. Steady‐state femto‐ and picosecond time‐resolved spectroscopy were employed to unveil the excited states dynamics in solution. Compared with the results obtained from the corresponding model compounds, the Triad is an efficient light collector over the entire visible spectral range and the fluorescence occurs mostly from the core with a quantum yield as high as 60 %. The results suggest that selective excitation of the naphthalenemonoimide chromophores results in an efficient energy transfer that occurs in a cascade fashion (through the perylenediimide chromophores) towards the terrylenediimide core with time constants of <200 fs and 3.7 ps. Naphthalenemonoimide chromophores can also transfer their excitation energy to the terrylenediimide core directly via two parallel pathways with time constants of 1.5 and 8.4 ps, respectively. Additionally, single‐molecule confocal microscopy experiments revealed strong emission from the terrylenediimide unit upon excitation of the naphthalenemonoimide chromophores. As time evolved, stepwise photobleaching of the multichromophoric Triad single molecules embedded in a PMMA polymer film was observed, resulting in a 96 percent probability of observing perylenediimide emission before final photobleaching under ambient conditions, substantiating the cascade energy transfer pathway. Under nitrogen atmosphere however, no perylenediimide emission could be observed for single Triad molecules embedded in a PMMA polymer film, likely as a result of the prolonged photostability of the terrylenediimide core in absence of oxygen.
Protonation of Zwitterionic Manganese and Rhenium Phosphoniostyryl Complexes (η5‐C5H5)(CO)2M––C(+PR3)=C(H)Ph: Experimental and DFT Study
Authors: Krivykh Vasily V. , Valyaev Dmitry A. , Utegenov Kamil I. , Mazhuga Andrei M. , Taits Elena S. , Semeikin Oleg V. , Petrovskii Pavel V. , Godovikov Ivan A. , Glukhov Ivan V. , Ustynyuk Nikolai A. 
Published: November 2010

AbstractStereoselective addition of tertiary phosphanes to manganese and rhenium phenylvinylidenes (η5‐C5H5)(CO)2M=C=C(H)Ph (1 M = Mn; 2 M = Re) gave the corresponding zwitterionic Z‐phosphoniostyryl adducts (η5‐C5H5)(CO)2M−−C(+PR3)=C(H)Ph (3 M = Mn, PR3 = PPh2Me; 4 Mn, PPhMe2; 5 Mn, PMe3; 6 Re, PPh2Me; 7 Re, PMe3). Protonation of 3–7 with HBF4·OEt2 resulted in the formation of the η2‐phosponioalkene complexes (η5‐C5H5)(CO)2M(η2‐E‐HC(+PR3)=C(H)Ph) (8 Mn, PPh2Me; 9 Mn, PPhMe2; 10 Mn, PMe3; 11 Re, PPh2Me; 12 Re, PMe3) rather than in the corresponding phosphoniocarbene complexes (η5‐C5H5)(CO)2M=C(+PR3)CH2Ph. It was shown by DFT calculations (B3LYP/6‐31G*) that the protonation of 5 proceeds at the metal atom followed by C,H‐reductive elimination in the intermediate hydride cis‐(η5‐C5H5)(CO)2(H)Mn−C(+PMe3)=C(H)Ph (14) to form the agostic complex (η5‐C5H5)(CO)2Mn{η2‐H–C(+PMe3)=C(H)Ph} (15) and subsequent isomerization of the latter into the final η2‐phosphonioalkene 10. In line with the theoretical data, the low‐temperature protonation (–80°C) of 3 with triflic acid in an NMR tube directly gave the corresponding phosponioalkene complex 8. Unlike 3, the protonation of their rhenium analogues 6 and 7 under the same conditions revealed the quantitative formation of cis‐hydride intermediates cis‐[(η5‐C5H5)(CO)2(H)Re−C(+PR3)=C(H)Ph]OTf (16, 17), which undergo conversion into the corresponding η2‐phosponioalkene complexes 11 and 12 at ca. –30°C
Effluent-dominated streams. Part 2: Presence and possible effects of pharmaceuticals and personal care products in Wascana Creek, Saskatchewan, Canada
Authors: Waiser Marley J , Humphries David , Tumber Vijay , Holm Jennifer 
Published: November 2010

Abstract
Recent worldwide surveys have not only established incomplete removal of pharmaceuticals and personal care products (PPCPs) by sewage treatment plants, but also their presence in surface waters receiving treated sewage effluent. Those aquatic systems where sewage effluent dominates flow are thought to be at the highest risk for ecosystem level changes. The city of Regina, Saskatchewan, Canada (population 190,400) treats its sewage at a modern tertiary sewage treatment facility located on Wascana Creek. The Wascana Creek hydrograph is dominated by one major event: spring snow melt. Thereafter, creek flow declines considerably and in winter treated sewage effluent makes up almost 100% of stream flow. Four water surveys conducted on the creek from winter 2005 to spring 2007 indicated that PPCPs were always present, in nanogram and sometimes microgram per liter concentrations downstream of the sewage treatment plant. This mixture included antibiotics, analgesics, antiinflammatories, a lipid regulator, metabolites of caffeine, cocaine and nicotine, and an insect repellent. Not surprisingly, concentrations of some PPCPs were highest in winter. According to hazard quotient calculations and homologue presence, ibuprofen, naproxen, gemfibrozil, triclosan, erythromycin, trimethoprim, and sulfamethoxazole were present in Wascana Creek at concentrations that may present a risk to aquatic organisms. The continual exposure to a mixture of pharmaceuticals as well as concentrations of un-ionized ammonia that far exceed Canadian and American water quality guidelines suggests that Wascana Creek should be considered an ecosystem at risk. Although the Wascana Creek study is regional in nature, the results highlight the considerable risks posed to aquatic organisms in such effluent-dominated ecosystems. Environ. Toxicol. Chem. 2011;30:508–519. © 2010 SETAC