bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of organic additives on formation and structure of polyelectrolyte‐oppositely charged surfactant complexes
Authors: Zakharova J. A. , Otdelnova M. V. , Aliev I. I. , Motyakin M. V. , Wasserman A. M. , Zezin A. B. , Kabanov V. A. 
Published: October 2006

AbstractEffect of butanol and Triton X‐100 on formation, supramolecular organization and local dynamics of poly(N‐ethyl‐4‐vinylpyridinium)‐dodecyl sulfate complexes have been studied by UV spectroscopy, high‐speed sedimentation, laser light scattering and electron spin resonance (ESR) spectroscopy. It was found that solubilization of butanol promotes aggregation of the complex species in solution and results in contraction of the region in which water‐soluble complexes are formed. On the contrary, highly aggregated complexes disaggregate up to molecularly dispersed state upon addition of Triton X‐100. It was found that under the experimental conditions neither butanol (up to 3 wt%) nor Triton X‐100 ([Triton X‐100]/[sodium dodecylsulfate] ≤ 1:1) cause destruction of the complexes. The results of ESR spin probe and spin label studies show that in both cases supramolecular realignments are accompanied by a slight increase of the local molecular mobility of surfactant ions in the complex micelles, segmental mobility of polyelectrolyte being unchanged. Copyright © 2006 John Wiley & Sons, Ltd.
Pilot evaluation of hypnosis for the treatment of hot flashes in breast cancer survivors
Authors: Elkins Gary , Marcus Joel , Stearns Vered , Hasan Rajab M. 
Published: October 2006

AbstractThis single arm, pilot study investigated the use of hypnosis to reduce hot flashes in 16 breast cancer survivors. Each patient provided baseline data and received 4 weekly sessions of hypnosis that followed a standardized transcript. Patients were also instructed in self‐hypnosis. Throughout the clinical care, patients completed daily diaries of the frequency and severity of their hot flashes. Patients also completed baseline and post‐treatment ratings of the degree to which hot flashes interfered with daily activities and quality of life. Results indicated a 59% decrease in total daily hot flashes and a 70% decrease in weekly hot flash scores from their baselines. There was also a significant decrease in the degree to which hot flashes interfered with daily activities for all measures including work, social activities, leisure activities, sleep, mood, concentration, relations with others, sexuality, enjoyment of life, and overall quality of life. This pilot study suggests that clinical hypnosis may be an effective non‐hormonal and non‐pharmacological treatment for hot flashes. A randomized, controlled clinical trial is planned to more definitively elucidate the efficacy and applicability of hypnosis for reducing hot flashes. Copyright © 2006 John Wiley & Sons, Ltd.
The n‐factor of nonsorted circles along a climate gradient in Arctic Alaska
Authors: Kade A. , Romanovsky V. E. , Walker D. A. 
Published: October 2006

AbstractThree study sites were selected on zonal sites from north to south along a climate gradient in Arctic Alaska. Air and mineral soil surface temperatures of nonsorted circles and adjacent well‐vegetated tundra plots were monitored from September 2003 through September 2004, and the depths of vegetation, soil organic horizons and snow were measured. N‐factors, the ratio of ground‐surface temperature to air temperature, were determined for the summer and winter seasons. N‐factors and thaw depths were greater for relatively barren nonsorted circles than for adjacent well‐vegetated tundra. Along the climate gradient, the thickness of vegetation, soil organic layer and snow increased from north to south, while n‐factors and thaw depths decreased at bare circles from 1.43 ± 0.02 to 0.74 ± 0.01 and from 81.2 ± 1.4 cm to 59.5 ± 2.4 cm, respectively, and at the tundra from 0.99 ± 0.02 to 0.17 ± 0.01 and from 62.6 ± 1.4 cm to 21.0 ± 2.8 cm, respectively. Copyright © 2006 John Wiley & Sons, Ltd.
High resolution crystal structures of unliganded and liganded human liver ACBP reveal a new mode of binding for the acyl‐CoA ligand
Authors: Taskinen Jukka P. , van Aalten Daan M. , Knudsen Jens , Wierenga Rik K. 
Published: October 2006

AbstractThe acyl‐CoA binding protein (ACBP) is essential for the fatty acid metabolism, membrane structure, membrane fusion, and ceramide synthesis. Here high resolution crystal structures of human cytosolic liver ACBP, unliganded and liganded with a physiological ligand, myristoyl‐CoA are described. The binding of the acyl‐CoA molecule induces only few structural differences near the binding pocket. The crystal form of the liganded ACBP, which has two ACBP molecules in the asymmetric unit, shows that in human ACBP the same acyl‐CoA binding pocket is present as previously described for the bovine and Plasmodium falciparum ACBP and the mode of binding of the 3′‐phosphate‐AMP moiety is conserved. Unexpectedly, in one of the acyl‐CoA binding pockets the acyl moiety is bound in a reversed mode as compared with the bovine and P. falciparum structures. In this binding mode, the myristoyl‐CoA molecule is fully ordered and bound across the two ACBP molecules of the crystallographic asymmetric unit: the 3′‐phosphate‐AMP moiety is bound in the binding pocket of one ACBP molecule and the acyl chain is bound in the pocket of the other ACBP molecule. The remaining binding pocket cavities of these two ACBP molecules are filled by other ligand fragments. This novel binding mode shows that the acyl moiety can flip out of its classical binding pocket and bind elsewhere, suggesting a mechanism for the acyl‐CoA transfer between ACBP and the active site of a target enzyme. This mechanism is of possible relevance for the in vivo function of ACBP. Proteins 2007. © 2006 Wiley‐Liss, Inc.
A novel cross‐linked RNase A dimer with enhanced enzymatic properties
Authors: Simons Brigitte L. , Kaplan Harvey , Fournier Sylvie M. , Cyr Terry , Hefford Mary Alice 
Published: October 2006

AbstractA new cross‐linked ribonuclease A (RNase A) dimer composed of monomeric units covalently linked by a single amide bond between the side‐chains of Lys66 and Glu9 is described. The dimer was prepared in the absence of water by incubating a lyophilized preparation of RNase, sealed under vacuum, in an oven at 85°C. It was determined that the in vacuo procedure does not induce any significant conformational changes to the overall structure of RNase A, yet the amide cross‐link has an increased acid lability, indicating that it is exposed and conformationally strained. Examination of X‐ray crystallographic structures indicates that Lys66 and Glu9 are not close enough for the in vacuo dimer to adopt any of the known domain‐swapped conformations. Therefore, the in vacuo RNase A dimer appears to be a novel dimeric structure. The in vacuo RNase A dimer also exhibits a twofold increase in activity over monomeric RNase A on a per monomer basis. This doubling of enzymatic activity was shown using dsRNA and ssRNA as substrates. In addition to this enhanced ability to degrade RNA, the dimer is not inhibited by the cellular ribonuclease inhibitor protein (cRI). Proteins 2007. © 2006 Wiley‐Liss, Inc.
Origin of functional diversity among tetrameric voltage‐gated channels
Authors: Anselmi Claudio , Carloni Paolo , Torre Vincent 
Published: October 2006

AbstractThe aim of the present work is to relate functional differences of voltage‐gated K+ (Kv), hyperpolarization‐activated cyclic nucleotide‐gated (HCN), and cyclic nucleotide gated (CNG) channels to differences in their amino acid sequences. By means of combined bioinformatic sequence analyses and homology modelling, we suggest that: (1) CNG channels are less voltage‐dependent than Kv channels since the charge of their voltage sensor, the S4 helix, is lower than that of Kv channels and because of the presence of a conserved proline in the S4–S5 linker, which is quite likely to uncouple S4 from S5 and S6. (2) In HCN channels, S4 features a higher net positive charge with respect to Kv channels and an extensive network of hydrophobic residues, which is quite likely to provide a tight coupling among S4 and the neighboring helices. We suggest insights on the gating of HCN channels and the reasons why they open with membrane hyperpolarization and with a significantly longer time constant with respect to other channels. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Influence of the protein matrix on intramolecular histidine ligation in ferric and ferrous hexacoordinate hemoglobins
Authors: Halder Puspita , Trent James T. , Hargrove Mark S. 
Published: October 2006

AbstractPresent in most organisms, hexacoordinate hemoglobins (hxHbs) are proteins that have evolved the capacity for reversible bis‐histidyl heme coordination. The heme prosthetic group enables diverse protein functionality, such as electron transfer, redox reactions, ligand transport, and enzymatic catalysis. The reactivity of heme is greatly effected by the coordination and noncovalent chemical environment imposed by its connate protein. Of considerable interest is how the hxHb globin fold achieves reversible intramolecular coordination while still enabling high‐affinity binding of oxygen, nitric oxide, and other small ligands. Here we explore this question by examining the role of the protein matrix on coordination behavior in a group of hxHbs from animals, plants, and bacteria, including human neuroglobin and cytoglobin, a nonsymbiotic hemoglobin from rice, and a truncated hemoglobin from the cyanobacterium Synechocystis. This is done with a set of experiments measuring the reduction potentials of each wild‐type hxHb and its corresponding mutant protein where the reversibly bound histidine (the distal His) has been replaced with a noncoordinating side chain. These reduction potentials, coupled with studies of the mutant proteins saturated with exogenous imidazole, enable us to assess the effects of the protein matrices on histidine coordination. Our results show significant variation among the hxHbs, demonstrating flexibility in the globin moiety's ability to regulate reversible coordination. This regulation is particularly evident in the plant nonsymbiotic hemoglobins, where ferric state histidine coordination affinity is substantially lowered by the protein matrix. Proteins 2007. © 2006 Wiley‐Liss, Inc.
In‐line flame arresters to prevent flashback of thermal combustion units
Authors: Heidermann Thomas , Davies Michael 
Published: October 2006

AbstractThermal combustion units in chemical, pharmaceutical, and petrochemical plants use burner systems for thermal waste disposal to reduce emissions. The advantage of premixed burner units is related primarily to greater stability of flame, the reduction of NOx emissions, and control and technical reasons. Unfortunately, the production of premixed flames requires the highly flammable fuel and oxidant gases to be mixed in confined chambers before they are burned. To form the flame, the mixed gases must pass through the burner exit ports where combustion takes place. Under certain conditions, the flame can burn back through the burner exit ports and ignite the potentially explosive gas–air mixture in the piping system. Of course, burner system designers have the expertise to design suitable burners that prevent flashback by flow‐control measures.Flame arresters can be used as a secondary measure to increase plant safety. Flame arresters are autonomous safety devices that protect workers, environment, and plant against deflagration and detonation caused by flashback from a combustion process while allowing vapor flow.To maximize the effectiveness of flame arresters, attention should be given to proper selection, application, and maintenance of the device. For this, it is most important to know under which conditions the arrester was tested and have the capability to decide which test standard is the most effective for the specific application.This article focuses on the application of in‐line deflagration vs. in‐line detonation arresters and provides design criteria based on live field testing on when to use which arrester type. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2007
A real‐life example of choosing an inherently safer process option
Authors: Study Karen 
Published: October 2006

AbstractAlthough choosing an inherently safer alternative may seem straightforward, sometimes what seems to be the most obvious alternative may not provide the best risk reduction. The process designer must maintain a broad perspective to be able to recognize all potential hazards when evaluating design options. All aspects of operation such as start‐up, shutdown, utility failure, as well as normal operation should be considered. Choosing the inherently safer option is best accomplished early in the option selection phase of a project. However, recycle back to the option selection phase may be needed if an option is not thoroughly evaluated early in the process. This report reviews a project to supply ammonia to a catalytic reactor. During the course of the project, an “inherently safer” alternative was selected and later discarded because of issues uncovered during the detail design phase. The final option chosen will be compared to (1) the original design and (2) the initial “inherently safer” alternative. The final option was inherently safer than both the original design and the initial “inherently safer” alternative, even though the design team initially believed that it would not be. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2006
Structural study on the crystallization behavior of Sb3Te2 alloy for phase change memory
Authors: Sun Chang Woo , Lee Jeong Yong , Youm Minsoo , Kim Yong Tae 
Published: October 2006

AbstractThe atomic crystal structure of the Sb3Te2 binary alloy has been investigated with high‐resolution transmission electron microscopy (HR‐TEM) and fast Fourier transform patterns. As a result, there is inconsistency between the previous theoretical model and the experimental result. But, from the calculations of lattice parameters and the number of layers in the unit cell, it is found that the Sb3Te2 alloy can be crystallized into the Sb2Te structure with P$ \bar 3 $m1 space group and the difference between stacking sequences of the Sb3Te2 and the Sb2Te structures has been discussed with the proposed atomic arrangement model of unit cells. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab initio computational modeling on the tautomerism of monochalcogenocarboxylic acids CH3C(O)XH (X = S, Se, and Te) in the polar and aprotic solution
Authors: Li Qiang‐Gen , Liang Guo‐Ming , Wang Xin , Chu San‐Yan , Ren Yi 
Published: October 2006

AbstractComputational modeling by an ab initio molecular orbital method (HF and MP2) with the 6‐311+G(d,p) and 6‐311++G(2df,2pd) basis sets on the tautomerism of three monochalcogenocarboxylic acids CH3C(O)XH (X = S, Se, and Te) in the polar and aprotic solution tetrahydrofuran (THF) was undertaken using the combined supramolecular/continuum method, in which CH3OCH3 was considered as a realistic model for THF in the supermolecule. Our calculations showed that the tautomerism involving CH3OCH3 not only gives the preference of the enol form CH3C(X)OH (X = S, Se, and Te) in the tautomeric equilibrium, but also significantly lowers the tautomeric barriers by >34 kJ/mol in THF solution. These results support the experiments of Kato and coworkers, in contrast with earlier Delaere et al.'s theoretical prediction for the tautomeric barrier of thioformic acid HC(O)SH…O(CH3)2, in which the barrier is increased by ∼6 kJ/mol relative to reactants complex because of the constraint in locating the tautomeric transition structure. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Characterization of compounds in the Chinese herbal drug Mu‐Dan‐Pi by liquid chromatography coupled to electrospray ionization mass spectrometry
Authors: Xu Shun‐jun , Yang Liu , Zeng Xing , Zhang Mian , Wang Zheng‐tao 
Published: October 2006

AbstractCortex Moutan is a well‐known traditional Chinese medicine derived from Paeonia suffruticosa ANDREWS. However, root cortices of P. delavayi and P. decomposita also are used under the name of this drug in some regions such as Yunnan and Sichuan Provinces, respectively. In order to make a comparison of their chemical constituents, the compounds of the three Paeonia species were analyzed by high‐performance liquid chromatography‐diode array detection/electrospray ionization and quadrupole‐time‐of‐flight tandem mass spectrometry (HPLC‐DAD/ESI‐MS2). A total of 50 compounds were observed in the 50% (v/v) methanolic extracts, including 17 monoterpenes, 14 galloyl glucoses, 10 acetophenones, 5 phenolic acids, 3 flavonoids and 1 triterpene. These chemical constituents were separated on a C18 column and identified or tentatively characterized based on UV spectra and MS fragmentation behavior. The chemical compositions of the three Paeonia species were found to have many differences. Paeonol was the predominant constituent of P. suffruticosa and P. decomposita, while P. delavayi contained albiflorin and more galloyl glucoses than the other two Paeonia species. Most of these identified compounds have been reported from P. delavayi and P. decomposita for the first time. The ESI‐MS fragmentation behavior of monoterpene glycosides, acetophenones and galloyl glucoses was also investigated successively, and appropriate characteristic pathways were proposed. The large differences in chemical compounds among the three Paeonia species strongly encouraged further comparison of the bioactivities of these three species. Copyright © 2006 John Wiley & Sons, Ltd.
Selective detection of homocysteine by laser desorption/ionization mass spectrometry
Authors: Su Chih‐Lin , Tseng Wei‐Lung 
Published: October 2006

AbstractThis article describes the use of 2,3‐naphthalenedicarboxaldehyde (NDA) as a selective probe for the determination of homocysteine (HCys) via fluorescence measurement and laser desorption/ionization mass spectrometry (LDI‐MS). The derivatives of three aminothiols–HCys, glutathione (GSH), and γ‐glutamylcysteine (γ‐Glu‐Cys)–with NDA under alkaline conditions possess different fluorescence emission characteristics, which allow us to identify them from amines, amino acids, and thiols. By selecting appropriate pH and excitation wavelengths, the limits of detection (LODs) at a signal‐to‐noise ratio of 3 were 5.2, 1.4 and 16 nM for HCys, GSH and γ‐Glu‐Cys, respectively. Additionally, strong UV absorption of the NDA‐HCys derivative was further observed at 331 nm; it could be directly detected by LDI‐MS with a 337‐nm nitrogen laser. Selective detection of HCys has been achieved by conducting the LDI‐MS of the NDA‐HCys derivative, which was found at m/z 406.9. The lowest detectable concentration of the NDA‐HCys derivative in this approach was 500 nM. Quantitative determination of HCys in urine samples was accomplished by LDI‐MS. Also, a calibration curve was created from plasma samples spiked with standard HCys (20–100 µM). The experimental results suggest that our proposed methods have great potential in clinical diagnosis and metabolomics application. Copyright © 2006 John Wiley & Sons, Ltd.
Compensation voltage shifting in high‐field asymmetric waveform ion mobility spectrometry‐mass spectrometry
Authors: Kolakowski Beata M. , McCooeye Margaret A. , Mester Zoltan 
Published: October 2006

AbstractThe separation and ion focusing properties of High‐Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) depend on desolvated ions entering the device, leading to a compound‐specific, reproducible compensation voltage (CV) for each ion. This study shows that the conditions identified for stable spray and satisfactory ion desolvation in normal electrospray ionization mass spectrometry (ESI‐MS) operation might significantly differ from those required for FAIMS‐MS. In a typical setup with high‐flow electrospray conditions, ions could be incompletely desolvated, resulting in the formation of unidentified clusters with differing behavior in a FAIMS environment. This causes compound‐specific shifts of as much as 10 V in CV values when the mobile phase composition and/or flow rate are varied. The shifts diminish and finally disappear when the flow rate of methanol, used as mobile phase, is reduced to 40 µL/min and that of acetonitrile to 20 µL/min. The reproducibility of the observed CV was determined by scanning the CV while infusing a five‐component mixture into a 400 µL/min flow of methanol or 50:50 acetonitrile/water. The relative standard deviation (RSD) for these multiple scans ranged from 0.7% to 6%. Therefore, under a constant set of experimental parameters, the CV does not shift appreciably. These observations have an impact on method development strategies. High flow rates can be used with the FAIMS device, since the CV values are reproducible, but it is likely that clusters are forming. Therefore, CV scans should be performed under conditions which mimic the chromatographic elution or flow injection analysis conditions, including matrix composition, to minimize errors in CV determination. An alternative approach is to determine the liquid flow rate at which the CV becomes compound‐specific and to split the mobile phase stream accordingly. These experimental results may be specific to the setup used for this study and may not be directly applicable to other instrument FAIMS devices. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Quantification of small molecule organic acids from Mycobacterium tuberculosis culture supernatant using ion exclusion liquid chromatography/mass spectrometry
Authors: Goodwin Michael B. , Boshoff Helena I. , Barry Clifton E. , Dowd Cynthia S. 
Published: October 2006

AbstractQuantitative analysis of cellular small molecule organic acids of intermediary metabolism can provide critical insight into bacterial metabolic pathways. The concentration of these metabolites in culture supernatant varies at different growth stages or under particular environmental conditions reflecting both the energy and the biosynthetic needs, yielding metabolic information about the microorganism. The method described here utilizes ion exclusion chromatography with formic acid, coupled with a mass‐selective detector using selective ion monitoring with negative mode electrospray ionization (SIM ES−), to detect and quantify several small organic acids in culture supernatants. The µM limits of quantitation (LOQs) were found to be 5.5 ± 0.9 for pyruvate, 7.0 ± 0.4 for malate, 2.5 ± 0.5 for succinate, 12.7 ± 0.8 for lactate, and 6.6 ± 0.2 for fumarate. The method was used to detect and quantify these acids in the culture supernatants from Mycobacterium tuberculosis. Supernatant samples were spiked with stable‐isotope‐labeled internal standards, and the organic acids were quantified by isotope ratiometry. Published in 2006 by John Wiley & Sons, Ltd.
Sizing a trial to alter the trajectory of health behaviours: methods, parameter estimates, and their application
Authors: Murray David M. , Blitstein Jonathan L. , Hannan Peter J. , Baker William L. , Lytle Leslie A. 
Published: October 2006

AbstractGroup‐randomized trials often involve repeat observations on the same participants. When there are no more than two observations from each participant, standard mixed‐model regression methods for a pretest–posttest design can be used. When there are more than two observations from each participant, random coefficients models may be useful. This paper describes the random coefficients analysis appropriate to data from an extended nested cohort design and presents the methods for power analysis and sample size calculations based on that analysis. We provide estimates for the parameters required for those calculations for a number of adolescent health behaviours. We also show how the estimates can be used to plan a future trial. Copyright © 2006 John Wiley & Sons, Ltd.