bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Characterization, and Hydrolysis Products of (η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH2 − Structural Characterization of a Complex Containing η1‐, η2‐, and μ:η1,η1‐Pyrazolato Ligands and a Complex Containing a Terminal Hydroxo Ligand
Authors: Yu Zhengkun , Knox John E. , Korolev Andrey V. , Heeg Mary Jane , Schlegel H. Bernhard , Winter Charles H. 
Published: November 2004

AbstractTreatment of alane−ethyldimethylamine with 3,5‐di‐tert‐butylpyrazole (tBu2pzH) in a 2:3 molar ratio afforded [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH2] in 57% yield. Hydrolysis of [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH2] afforded variable mixtures of Al(tBu2pz)3, [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH(OH)], and [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH(η1‐tBu2pz)]. The structures of all new complexes were assigned from spectral and analytical data. In addition, the X‐ray crystal structures of [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH(OH)] and [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH(η1‐tBu2pz)] were determined. [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH(OH)] crystallizes as a dimeric molecule, and contains two bridging pyrazolato ligands, one η2‐pyrazolato ligand, as well as terminal hydrido and hydroxo ligands. The hydroxo and η2‐pyrazolato ligands possess a syn‐relationship within the dimer. The hydroxy group proton does not participate in dihydrogen bonding, and instead appears to be intramolecularly hydrogen‐bonded to the π‐cloud of the η2‐pyrazolato ligand. The overall structure of [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH(η1‐tBu2pz)] is very similar to that of [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH(OH)], except that the η1‐ and η2‐pyrazolato ligands have an anti‐disposition within the dimer. Molecular orbital calculations were carried out on [(η2‐tBu2pz)AlH(μ:η1,η1‐tBu2pz)2AlH(OH)] to understand the hydrogen bonding and the η2‐pyrazolato ligand coordination. The calculations predict that there is a 1.4 kcal/mol energy difference between η1‐ and η2‐pyrazolato ligand coordination, which implies that the observed η2‐pyrazolato ligand occurs due to accommodation of the bulky tert‐butyl groups. The intramolecular hydrogen bond between the hydroxo ligand proton and the π‐cloud of the η2‐pyrazolato ligand is estimated to have a bond strength of 3.7 kcal/mol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Effectiveness of dimethylpolysiloxane during deep frying
Authors: Márquez‐Ruiz Gloria , Velasco Joaquín , Dobarganes M. Carmen 
Published: November 2004

AbstractIn the last decades, silicones and particularly dimethylpolysiloxane (DMPS) added to oils and fats at very low concentrations (1–5 mg/kg) have been widely applied as inhibitors of thermoxidative reactions in deep frying. In this review, information available on the mechanisms of DMPS action during the frying process is summarised. Studies on samples submitted to high temperature in the absence of foods, as well as those on continuous and discontinuous frying, are commented upon. It is concluded that the different effects reported can be attributed to the high number of variables interacting during frying. The maximum effectiveness of DMPS was obtained in discontinuous frying operations when the oil surface becomes unprotected against oxidation due to the absence of the food. On the contrary, in industrial continuous frying, the addition of DMPS was found to be ineffective due to the protection of the surface by steam originating from the food.
Attenuation of telomerase activity by hammerhead ribozyme targeting human telomerase RNA induces growth retardation and apoptosis in human breast tumor cells
Authors: Yeo Marie , Rha Sung Young , Jeung Hei Cheul , Hu Shen Xiong , Yang Sang Hwa , Kim Yang Seok , An Sung Whan , Chung Hyun Cheol 
Published: November 2004

AbstractRibozyme possesses specific endoribonuclease activity and catalyzes the hydrolysis of specific phosphodiester bonds, which results in the cleavage of target RNA sequences. Here, we evaluated the ability of hammerhead ribozymes targeting human telomerase RNA (hTR) to inhibit the catalytic activity of telomerase and the proliferation of cancer cells. Hammerhead ribozymes were designed against 7 NUX sequences located in open loops of the hTR secondary structure. We verified the ribozyme specificity by in vitro cleavage assay by using a synthetic RNA substrate. Subsequently, we introduced ribozyme expression vector into human breast tumor MCF‐7 cells and assessed the biologic effects of ribozyme. Hammerhead ribozyme R1 targeting the template region of hTR efficiently cleaved hTR in vitro, and stable transfectants of this ribozyme induced the degradation of target hTR RNA and attenuated telomerase activity in MCF‐7 cells. Moreover, the ribozyme R1 transfectant displayed a significant telomere shortening and a lower proliferation rate than parental cells. Clones with reduced proliferation capacity showed enlarged senescence‐like shapes or highly differentiated dendritic morphologies of apoptosis. In conclusion, the inhibition of telomerase activity by hammerhead ribozyme targeting the template region of the hTR presents a promising strategy for inhibiting the growth of human breast cancer cells. © 2004 Wiley‐Liss, Inc.
Selective adduct formation by furan chemical ionization reagent in gas chromatography ion trap mass spectrometry
Authors: Tzing Shin‐Hwa , Ghule Anil , Chang Jia‐Yaw , Ling Yong‐Chien 
Published: November 2004

AbstractThe analytical potential of furan as a chemical ionization (CI) reagent was evaluated for selectivity with nine monosubstituted naphthalene compounds. The ion–molecule reactions of furan and tetrahydrofuran (THF) were compared with those of methane, methanol and acetonitrile (prominently producing [M + H]+ ion base peaks) with naphthalene compounds in chemical ionization mass spectrometry (CI‐MS). Reactions with furan predominantly show M+ and [M + 39]+ ions. Based on this phenomenon, investigations were carried out for some of the molecular factors such as proton affinity, substituent effects and the preferred site of [C3H3]+ ion attachment that influence reactivity in furan CI. High selectivity with different substituents is observed in the formation of [M + 39]+ adduct ion, suggesting its usefulness as selective ionization reagent liquid. The selectivity and sensitivity are illustrated in the analysis of mixture of amino acids. Furthermore, the structure determination and reaction mechanism study is characterized by collision‐activated dissociation experiments in CI‐MS/MS and CI‐MS/MS/MS. Copyright © 2003 John Wiley & Sons, Ltd.
Characterization of plant oligosaccharides by matrix‐assisted laser desorption/ionization and electrospray mass spectrometry
Authors: Matamoros Fernández Lobvi E. , Obel Nicolai , Scheller Henrik Vibe , Roepstorff Peter 
Published: November 2004

AbstractStructural characterization of arabinoxylans from wheat by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) and electrospray ionization (ESI) mass spectrometry using a Q‐TOF mass analyser (ESI‐Q‐TOF) or an ion trap (IT) mass analyser is presented. An arabinoxylan sample digested with endoxylanase A was analysed using MALDI‐TOF mass spectrometry (MS), resulting in the identification of molecular ions for structures with up to 22 monosaccharide residues. As the two‐component monosaccharides xylose and arabinose are isobaric, structures differing in the number of arabinose branching residues were indistinguishable based on molecular mass and also fragmentation pattern upon collision‐induced dissociation (CID). Permethylation followed by ESI‐CID analyses using ITMS was performed to obtain structural information regarding the number of arabinose branching residues and their spatial arrangement along the xylose backbone. Analysis of the signal corresponding to an oligomer with six monosaccharide residues showed the presence of at least four isomeric structures differing in degree of branching and position of the branched residue relative to the cleavage site of the enzyme. This is the first demonstration of the use of ESI‐ITMS for the structural characterization of arabinoxylan mixtures. Copyright © 2003 John Wiley & Sons, Ltd.
Liquid chromatography/atmospheric pressure ionization–mass spectrometry in drug metabolism studies
Authors: Kostiainen R. , Kotiaho T. , Kuuranne T. , Auriola S. 
Published: November 2004

AbstractThe study of the metabolic fate of drugs is an essential and important part of the drug development process. The analysis of metabolites is a challenging task and several different analytical methods have been used in these studies. However, after the introduction of the atmospheric pressure ionization (API) technique, electrospray and atmospheric pressure chemical ionization, liquid chromatography/mass spectrometry (LC/MS) has become an important and widely used method in the analysis of metabolites owing to its superior specificity, sensitivity and efficiency. In this paper the feasibility of LC/API‐MS techniques in the identification, structure characterization and quantitation of drug metabolites is reviewed. Sample preparation, LC techniques, isotope labeling, suitability of different MS techniques, such as tandem mass spectrometry, and high‐resolution MS in drug metabolite analysis, are summarized and discussed. Automation of data acquisition and interpretation, special techniques and possible future trends are also the topics of the review. Copyright © 2003 John Wiley & Sons, Ltd.
Cover Picture: Macromol. Biosci. 11/2004
Authors: Sannigrahi Biswajit , McGeady Paul , Khan Ishrat M. 
Published: November 2004

Cover: Helical poly(3‐methyl‐4‐vinylpyridine)(P3M4VP)/amino acid complexes have been prepared via acid‐base interaction of the achiral polymer with D and L amino acids. Formation of the helical structures was quite rapid and within a few minutes of the complexation process, well developed CD spectra were observed. Furthermore the complexes are compatible with HeLa cells, they minimally interfere with the adhesion and growth of HeLa cells on complex surfaces.Further details can be found in the Full Paper by B. Sannigrahi, P. McGeady, and I. M. Khan* on page 999.
Effects of velocity on maximal torque production in poststroke hemiparesis
Authors: Lum Peter S. , Patten Carolynn , Kothari Dhara , Yap Ruth 
Published: November 2004

AbstractImpaired torque production is a major physical impairment following stroke, and has been studied extensively in isometric conditions. However, functional use of a limb requires torque production during movement, and the effects of velocity on maximal torque production may be abnormally enhanced in the paretic limb. The purpose of this study was to quantify the effects of movement velocity on maximal torque production during isokinetic, concentric flexion and extension of the elbow in poststroke subjects. Three speeds were tested (30, 75, 120 deg/s) over a 100‐deg range of motion. To control for strength variations between subjects and limbs, isokinetic torques were normalized by peak isometric torque. As flexion velocity increased, paretic limb torque decreased at a greater rate than in the unaffected limb. During extension, paretic limb torque was much lower than torque in the unaffected limb at all speeds. In both flexion and extension, the disparity between limbs in the constant‐velocity torque–angle curves became more pronounced as velocity increased. Torque decreased 44% ± 7% in flexion and 63% ± 9% in extension as velocity increased from 30 to 120 deg/s, whereas the corresponding decreases in the unaffected limb were only 9% ± 5% in flexion and 16% ± 4% in extension. No electromyographic (EMG) abnormalities were observed during flexion. During extension, EMG data provided evidence for abnormally increased antagonist coactivation in brachioradialis and markedly reduced activation in triceps as potential contributors to the decreased extension torques. The finding that movement velocity produces large deficits in maximal torque might explain why functional use of the paretic limb is often impaired even though isometric strength appears adequate. Muscle Nerve, 2004
An interesting contrast: effects of maleic acid and styrene on the synthesis of functional poly(methyl methacrylate) microspheres
Authors: Li Songjun , Hu Jie , Liu Bailing 
Published: November 2004

AbstractThe effects of maleic acid and styrene on the polymerization of methyl methacrylate (MMA) have been studied. Both comonomers play a considerable role in terms of particle size and MMA conversion. The polymerization of MMA in the presence of maleic acid can result in larger particles and a higher MMA conversion. However, in the presence of styrene, the polymerization process yields smaller particles and low MMA conversion. This can be related to the different properties of maleic acid and styrene. Maleic acid, a hydrophilic and electron‐withdrawing comonomer, can play a positive role in stabilizing the particles and increasing MMA activation. However, for styrene, these effects are reversed due to its opposite properties. The change in particle size may be caused by the change in particle stabilization. The change of MMA conversion can be kinetically attributed to the effects of maleic acid and styrene on the activation process. Copyright © 2004 Society of Chemical Industry
1,5‐Diphenyl‐1,4‐diyn‐3‐one: A highly efficient photoinitiator
Authors: Liska Robert , Seidl Bernhard 
Published: November 2004

AbstractIn a continuation of our research on new chromophores for photoinitiators (PIs), we investigated a triple‐bond‐containing benzophenone derivative. 1,5‐Diphenyl‐1,4‐pentadiyn‐3‐one (2) was prepared from phenylacetylene and ethyl formate by a one‐pot reaction. Differential scanning photocalorimetry experiments in lauryl acrylate of 2 showed surprisingly high activity for the double‐bond conversion and rate of polymerization at the lowest PI concentrations and even without any coinitiator. By the application of monomers with abstractable hydrogens, significant improvement in the photoreactivity was observed. Ultraviolet–visible spectroscopy revealed strong absorption up to 350 nm. Steady‐state photolysis experiments proved that the photochemistry of this compound was faster than that of benzophenone. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 101–111, 2005
A metrics suite for grammar‐based software
Authors: Power James F. , Malloy Brian A. 
Published: November 2004

AbstractOne approach to measuring and managing the complexity of software, as it evolves over time, is to exploit software metrics. Metrics have been used to estimate the complexity of the maintenance effort, to facilitate change impact analysis, and as an indicator for automatic detection of a transformation that can improve the quality of a system. However, there has been little effort directed at applying software metrics to the maintenance of grammar‐based software applications, such as compilers, editors, program comprehension tools and embedded systems. In this paper, we adapt the software metrics that are commonly used to measure program complexity and apply them to the measurement of the complexity of grammar‐based software applications. Since the behaviour of a grammar‐based application is typically choreographed by the grammar rules, the measure of complexity that our metrics provide can guide maintainers in locating problematic areas in grammar‐based applications. Copyright © 2004 John Wiley & Sons, Ltd.
Granger causality of the inflation–growth mirror in accession countries*
Authors: Gillman Max , Nakov Anton 
Published: November 2004

AbstractThe paper presents a model in which the exogenous money supply causes changes in the inflation rate and the output growth rate. While inflation and growth rate changes occur simultaneously, the inflation acts as a tax on the return to human capital and in this sense induces the growth rate decrease. Shifts in the model's credit sector productivity cause shifts in the income velocity of money that can break the otherwise stable relationship between money, inflation, and output growth. Applied to two accession countries, Hungary and Poland, a VAR system is estimated for each that incorporates endogenously determined multiple structural breaks. Results indicate Granger causality positively from money to inflation and negatively from inflation to growth for both Hungary and Poland, as suggested by the model, although there is some feedback to money for Poland. Three structural breaks are found for each country that are linked to changes in velocity trends, and to the breaks found in the other country.
Transoesophageal echocardiography is unreliable for cardiac output assessment after cardiac surgery compared with thermodilution*
Authors: Bettex D. A. , Hinselmann V. , Hellermann J. P. , Jenni R. , Schmid E. R. 
Published: November 2004

SummaryThis randomised, single‐blind, double‐control study compared and established prospectively the best transoesophageal echocardiography methods for determining cardiac output in patients after cardiac surgery. Thirty patients undergoing coronary artery bypass grafting were included. Measurements were taken postoperatively, after stabilisation in the intensive care unit. Cardiac output was determined by transoesophageal echocardiography in randomised order through the aortic, mitral, and pulmonary valves, right and left ventricular outflow tracts, transgastric surface areas of the left ventricle and left ventricle two‐dimensional volumes (Simpson's rules). ‘Eyeball guessing’ was done off‐line. The best results were transaortic measurements using the triangular shape assumption of valve opening, but some values deviated considerably, and none of these approaches reached the limit of agreement set at 30% when compared to thermodilution. Eyeball guessing was comparable to the best transoesophageal echocardiography measurements. We conclude that transoesophageal echocardiography is an unreliable tool for determination of cardiac output in intensive care after cardiac surgery.
Prescription errors in UK critical care units
Authors: Ridley S. A. , Booth S. A. , Thompson C. M. ,   the Intensive Care Society's Working Group on Adverse Incidents
Published: November 2004

SummaryDrug prescription errors are a common cause of adverse incidents and may be largely preventable. The incidence of prescription errors in UK critical care units is unknown. The aim of this study was to collect data about prescription errors and so calculate the incidence and variation of errors nationally. Twenty‐four critical care units took part in the study for a 4‐week period. The total numbers of new and re‐written prescriptions were recorded daily. Errors were classified according to the nature of the error. Over the 4‐week period, 21 589 new prescriptions (or 15.3 new prescriptions per patient) were written. Eighty‐five per cent (18 448 prescriptions) were error free, but 3141 (15%) prescriptions had one or more errors (2.2 erroneous prescriptions per patient, or 145.5 erroneous prescriptions per 1000 new prescriptions). The five most common incorrect prescriptions were for potassium chloride (10.2% errors), heparin (5.3%), magnesium sulphate (5.2%), paracetamol (3.2%) and propofol (3.1%). Most of the errors were minor or would have had no adverse effects but 618 (19.6%) errors were considered significant, serious or potentially life threatening. Four categories (not writing the order according to the British National Formulary recommendations, an ambiguous medication order, non‐standard nomenclature and writing illegibly) accounted for 47.9% of all errors. Although prescription rates (and error rates) in critical care appear higher than elsewhere in hospital, the number of potentially serious errors is similar to other areas of high‐risk practice.
Activator protein‐1 signalling pathway and apoptosis are modulated by poly(ADP‐ribose) polymerase‐1 in experimental colitis
Authors: Zingarelli Basilia , Hake Paul W. , Burroughs Timothy J. , Piraino Giovanna , O'Connor Michael , Denenberg Alvin 
Published: November 2004

SummaryPoly(ADP‐ribose) polymerase‐1 (PARP‐1) is activated in response to DNA injury in the nucleus of eukaryotic cells and has been implicated in intestinal barrier dysfunction during inflammatory bowel diseases. In this study we investigated whether PARP‐1 may regulate the inflammatory response of experimental colitis at the level of signal transduction mechanisms. Mice genetically deficient of PARP‐1 (PARP‐1–/–) and wild‐type littermates were subjected to rectal instillation of trinitrobenzene sulphonic acid (TNBS). Signs of inflammation were monitored for 14 days. In wild‐type mice, TNBS treatment resulted in colonic ulceration and marked apoptosis, which was associated with decreased colon content of the antiapoptotic protein Bcl‐2, whereas the proapoptotic Bax was unchanged. Elevated levels of plasma nitrate/nitrite, metabolites of nitric oxide (NO), were also found. These inflammatory events were associated with activation of c‐Jun‐NH2 terminal kinase (JNK), phosphorylation of c‐Jun and activation of the nuclear transcription factor activator protein‐1 (AP‐1) in the colon. In contrast, PARP‐1–/– mice exhibited a significant reduction of colon damage and apoptosis, which was associated with increased colonic expression of Bcl‐2 and lower levels of plasma nitrate/nitrite when compared to wild‐type mice. Amelioration of colon damage was associated with a significant reduction of the activation of JNK and reduction of the DNA binding of AP‐1. The data indicate that PARP‐1 exerts a pathological role in colitis possibly by regulating the early stress‐related transcriptional response through a positive modulation of the AP‐1 and JNK pathways.
Complement component C7 deficiency in two Spanish families
Authors: Barroso Sonia , Sánchez Berta , Álvarez Antonia José , López‐Trascasa Margarita , Lanuza Amparo , Luque Rafael , Wichmann Ingeborg , Núñez‐Roldán Antonio 
Published: November 2004

SummaryDifferent genetic mutations have been described in complement component C7 deficiency, a molecular defect clinically associated with an increased susceptibility to neisserial recurrent infections. In this work we report the genetic basis of C7 deficiency in two different Spanish families (family 1 and family 2). In family 1, of Gypsy ethnical background, exon‐specific polymerase chain reaction and sequencing revealed a not previously described single base deletion of nucleotide 1309 (exon 10) in the patient, as well as in her father, leading to a stop codon that causes the premature truncation of the C7 protein (K416 X 419). Additionally, the patient and her mother displayed a missense mutation at position 1135 (exon 9) located in the first nucleotide of the codon GGG (CGG), resulting in a change of amino acid (G357R). This mutation was firstly described in individuals of Moroccan Sephardic Jewish ancestry and has been also reported among Spaniards. In family 2, another novel mutation was found in homozygosity in two siblings; a two base‐pair deletion of nucleotides 1922 and 1923 in exon 14 leading to the generation of a downstream stop codon causing the truncation of the C7 protein product (S620 X 630). Our results provide more evidence for the heterogeneous molecular basis of C7 deficiency as well as for the subsequent susceptibility to meningococcal disease, since different families carry different molecular defects. On the other hand, certain C7 defects appear to be prevalent in individuals from certain populations or living in defined geographical areas.