bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproductive and developmental effects and physical and chemical properties of pentaerythritol tetranitrate (PETN) in the rat
Authors: Quinn Michael J. , Crouse Lee C.B. , McFarland Craig A. , LaFiandra Emily M. , Johnson Mark S. 
Published: February 2009

AbstractPentaerythritol tetranitrate (PETN) is an explosive chemical that has been detected in environmental media. Although previous toxicology studies have shown PETN to be relatively benign, a lack of available information concerning developmental and reproductive effects from oral PETN exposure was needed. Sprague‐Dawley rats were exposed to oral daily adjusted volumetric doses of 0, 100, 500, or 1,000 mg PETN/kg body mass in a corn oil vehicle for up to 56 days. Mating, duration of gestation, body weight, feed consumption, overall condition of adults, and the number, sex, and condition of pups were recorded. Histological examinations were also performed on the ovaries, testes, and epididymides of animals from the control and the highest dose groups. Other environmental criteria, water solubility, octanol/water partition coefficient, and biodegradation rates of neat PETN were also determined. Only body weights and feed consumption were affected by treatment; however, these differences may be attributed more to volumetric adjustments of vehicle in the control and high‐dose groups than to PETN toxicity. No adverse effects on development or reproduction from PETN exposure were observed. Water solubility, octanol water partition coefficient, and water suspension and biodegradation rates suggest PETN is unlikely to transport or bioaccumulate in the environment to any appreciable extent. Additionally, biotic processes are most likely faster in breaking down PETN than the abiotic processes involved in dissolving PETN in water. Birth Defects Res (Part B) 86:65‐71, 2009. © 2009 Wiley‐Liss, Inc.
Using Penalized Splines to Model Age‐ and Season‐of‐Birth‐Dependent Effects of Childhood Mortality Risk Factors in Rural Burkina Faso
Authors: Becher Heiko , Kauermann Göran , Khomski Pavel , Kouyaté Bocar 
Published: February 2009

AbstractSeveral previous studies have identified risk factors for childhood mortality in high risk areas, such as Sub‐Saharan Africa. Among these are lifestyle factors related for example to nutrition or sanitation. Other factors are related to social class, ethnicity and poverty in general. Few studies have investigated a dependence of these factors by age and season of birth which is the focus in this study. We perform a survival analysis of 9121 children born between 1998 and 2001 in a rural area of western Burkina Faso. The whole population is under demographic surveillance since 1993. All cause mortality is used as the endpoint and follow‐up information until the age of five years is available. Recently developed spline regression methods are used for the analysis. Ethnic group, religion, age of mother, twin status, sex, and distance to next health center are used as covariates all of which having a clear effect on survival in standard Cox regression analysis. With penalized spline regression, a more detailed risk pattern is observed. Ethnicity is more related to death at early age, as well as age of mother. The effect of the risk factors considered also appear to be related with season of birth (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Assessment of Multiple Ordinal Endpoints
Authors: Häberle Lothar , Pfahlberg Annette , Gefeller Olaf 
Published: February 2009

AbstractRanking multivariate ordinal data and applying a non‐parametric test is an analytical approach commonly employed to compare treatments. We study three types of ranking and demonstrate how to combine them. The ranking methods rest upon partial orders of the multidimensional measurements or upon the sum of ranks. Since their usage is simple as regards statistical assumptions and technical realization, they are also adapted for health professionals without deep statistical knowledge. Our goal is discussing differences between the approaches and disclosing possible statistical consequences of their usage (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Isolation and identification of two novel SDS‐resistant secreted chitinases from Aeromonas schubertii
Authors: Liu Chao‐Lin , Shen Chia‐Rui , Hsu Fong‐Fu , Chen Jeen‐Kuan , Wu Pei‐Tzu , Guo Shang‐Hsin , Lee Wen‐Chien , Yu Feng‐Wei , Mackey Zachary B. , Turk John , Gross Michael L. 
Published: February 2009

AbstractTwo SDS‐resistant endochitinases, designated as ASCHI53 and ASCHI61, were isolated from Aeromonas schubertii in a soil sample from southern Taiwan. MALDI‐TOF mass measurement indicates the molecular weights of 53,527 for ASCHI53 and 61,202 for ASCHI61. N‐terminal and internal amino acid sequences were obtained, and BLAST analysis of the sequences and MS/MS peptide sequencing showed that they were novel proteins. Degradation of chitin by these two endochitinases gave rise to hexameric chitin oligosaccharide, a compound known to have several potent biomedical functions. ASCHI53 and ASCHI61 retained, respectively, 65% and 75%, of their chitinase activity in the presence of 5% SDS and 100% of their activity in the presence of 10% β‐mercaptoethanol. These results demonstrate that they are SDS‐resistant endochitinases and probably have a rigid structure. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Engineering the embryoid body microenvironment to direct embryonic stem cell differentiation
Authors: Bratt‐Leal Andrés M. , Carpenedo Richard L. , McDevitt Todd C. 
Published: February 2009

AbstractEmbryonic stem cells (ESCs) are pluripotent cells capable of differentiating into all somatic and germ cell types. The intrinsic ability of pluripotent cells to generate a vast array of different cells makes ESCs a robust resource for a variety of cell transplantation and tissue engineering applications, however, efficient and controlled means of directing ESC differentiation is essential for the development of regenerative therapies. ESCs are commonly differentiated in vitro by spontaneously self‐assembling in suspension culture into 3D cell aggregates called embryoid bodies (EBs), which mimic many of the hallmarks of early embryonic development, yet the 3D organization and structure of EBs also presents unique challenges to effectively direct the differentiation of the cells. ESC differentiation is strongly influenced by physical and chemical signals comprising the local extracellular microenvironment, thus current methods to engineer EB differentiation have focused primarily on spatially controlling EB size, adding soluble factors to the media, or culturing EBs on or within natural or synthetic extracellular matrices. Although most such strategies aim to influence differentiation from the exterior of EBs, engineering the microenvironment directly within EBs enables new opportunities to efficiently direct the fate of the cells by locally controlling the presentation of morphogenic cues. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Considering religion and beliefs in child protection and safeguarding work: is any consensus emerging?
Authors: Gilligan Philip 
Published: February 2009

AbstractDiverse, but significant, phenomena have combined to raise both the profile of issues related to religion and child abuse and the need for professionals to understand and respond appropriately to them. The nature of some of these issues is explored and attempts made to clarify them. Data collected by the author primarily from questionnaires completed by professionals involved in child protection and safeguarding work are analysed and discussed. Some patterns are identified and explored. Finally, it is suggested that, despite the apparent emergence of a more general recognition and acknowledgement of these issues amongst many professionals, relevant day‐to‐day practice remains largely dependent on individual views and attitudes. Moreover, practitioners are able to continue with ‘religion‐blind’ and ‘belief‐blind’ approaches without these being significantly challenged by agency policies or by professional cultures. Copyright © 2009 John Wiley & Sons, Ltd.
Design of Protonated Polyazamacrocycles Based on Phenanthroline Motifs for Selective Uptake of Aromatic Carboxylate Anions and Herbicides
Authors: Cruz Carla , Calisto Vânia , Delgado Rita , Félix Vítor 
Published: February 2009

AbstractThree novel large polyazamacrocycles containing two 1,10‐phenanthroline units connected by different polyamine spacers have been synthesised and their protonated forms used as receptors for several aromatic carboxylate anions. The receptors bind to the anions in a 1:1 stoichiometry and exhibit remarkable binding selectivity (see figure). Analysis shows that molecular recognition is governed by π–π stacking interactions and multiple NH⋅⋅⋅OC hydrogen bonds.magnified imageThree novel large polyazamacrocycles containing two 1,10‐phenanthroline (phen) units connected by two polyamine spacers of different length, [32]phen2N4, [30]phen2N6 and Me2[34]phen2N6, have been synthesised and their protonated forms used as receptors for binding studies with several aromatic carboxylate anions (benzoate (bzc−), 1‐naphthalate (naphc−), 9‐anthracenate (anthc−), pyrene‐1‐carboxylate (pyrc−), phthalate, (ph2−), isophthalate (iph2−), terephthalate (tph2−), 2,5‐dihydroxy‐1,4‐benzenediacetate (dihyac2−) and, 1,3,5‐benzenetricarboxylate (btc3−)) and three herbicides (4‐amino‐3,5,6‐trichloropyridine‐2‐carboxylate (ATCP−), dichlorophenoxyacetate (2,4‐D−) and glyphosate (PMG2−)) in water solution. The [30]phen2N6 receptor was found to be the most suitable for binding the anions considered in a 1:1 stoichiometry. The three receptors exhibit a remarkable binding selectivity towards the extended aromatic anion pyrc− at low pH values. Their binding affinities for the monocarboxylate anions decrease with the extension of the aromatic system in the order pyrc−>anthc−>naphc−>bzc−, which indicates the presence of π–π stacking interactions in the molecular recognition of these anions. Molecular dynamics simulations carried out for the binding of {H4[30]phen2N6}4+ and {H6Me2[34]phen2N6}6+ with pyrc−, anthc−, naphc−, iph2− and btc3− in water showed that these receptors adopt a folded conformation with the anion inserted between the two phen heads and that the molecular recognition is governed by π–π stacking interactions and multiple NH⋅⋅⋅OC hydrogen bonds. The binding free energies estimated theoretically are very similar to those found by potentiometric methods, which supports the proposed binding arrangement.
Gold‐ and Platinum‐Catalyzed Cycloisomerization of Enynyl Esters versus Allenenyl Esters: An Experimental and Theoretical Study
Authors: Marion Nicolas , Lemière Gilles , Correa Andrea , Costabile Chiara , Ramón Rubén S. , Moreau Xavier , de Frémont Pierre , Dahmane Rim , Hours Alexandra , Lesage Denis , Tabet Jean‐Claude , Goddard Jean‐Philippe , Gandon Vincent , Cavallo Luigi , Fensterbank Louis , Malacria Max , Nolan Steven P. 
Published: February 2009

AbstractEster‐way to heaven: Unexpected formation of bicyclo[3.1.0]hexene 4 was the main focus of combined experimental and theoretical studies on the Au‐catalyzed cycloisomerization of branched dienyne 1 (see scheme), which provided better understanding of the mechanistic details governing the cyclization of enynes bearing a propargylic ester group.magnified imageExperimental and theoretical studies on Au‐ and Pt‐catalyzed cycloisomerization of a branched dienyne with an acetate group at the propargylic position are presented. The peculiar architecture of the dienyne precursor, which has both a 1,6‐ and a 1,5‐enyne skeleton, leads, in the presence of alkynophilic gold catalysts, to mixtures of bicyclic compounds 3, 4, and 5. Formation of unprecedented bicyclo[3.1.0]hexene 5 is the main focus of this study. The effect of the ancillary ligand on the gold center was examined and found to be crucial for formation of 5. Further mechanistic studies, involving cyclization of an enantioenriched dienyne precursor, 18O‐labeling experiments, and DFT calculations, allowed an unprecedented reaction pathway to be proposed. We show that bicyclo[3.1.0]hexene 5 is likely formed by a 1,3‐OAc shift/allene–ene cyclization/1,2‐OAc shift sequence, as calculated by DFT and supported by Au‐catalyzed cyclization of isolated allenenyl acetate 7, which leads to improved selectivity in the formation of 5. Additionally, the possibility of OAc migration from allenyl acetates was supported by a trapping experiment with styrene that afforded the corresponding cyclopropane derivative. This unprecedented generation of a vinyl metal carbene from an allenyl ester supports a facile enynyl ester/allenenyl ester equilibrium. Further examination of the difference in reactivity between enynyl acetates and their corresponding [3,3]‐rearranged allenenyl acetates toward Au‐ and Pt‐catalyzed cycloisomerization is also presented.
Coupled Sensitizer–Catalyst Dyads: Electron‐Transfer Reactions in a Perylene–Polyoxometalate Conjugate
Authors: Odobel Fabrice , Séverac Marjorie , Pellegrin Yann , Blart Errol , Fosse Céline , Cannizzo Caroline , Mayer Cédric R. , Elliott Kristopher J. , Harriman Anthony 
Published: February 2009

AbstractUltrafast discharge of a single‐electron capacitor: A variety of intramolecular electron‐transfer reactions are apparent for polyoxometalates functionalized with covalently attached perylene monoimide chromophores, but these are restricted to single‐electron events. (et=electron transfer, cr=charge recombination, csr=charge‐shift reaction, PER=perylene, POM=polyoxometalate).magnified imageA new strategy is introduced that permits covalent attachment of an organic chromophore to a polyoxometalate (POM) cluster. Two examples are reported that differ according to the nature of the anchoring group and the flexibility of the linker. Both POMs are functionalized with perylene monoimide units, which function as photon collectors and form a relatively long‐lived charge‐transfer state under illumination. They are reduced to a stable π‐radical anion by electrolysis or to a protonated dianion under photolysis in the presence of aqueous triethanolamine. The presence of the POM opens up an intramolecular electron‐transfer route by which the charge‐transfer state reduces the POM. The rate of this process depends on the molecular conformation and appears to involve through‐space interactions. Prior reduction of the POM leads to efficient fluorescence quenching, again due to intramolecular electron transfer. In most cases, it is difficult to resolve the electron‐transfer products because of relatively fast reverse charge shift that occurs within a closed conformer. Although the POM can store multiple electrons, it has not proved possible to use these systems as molecular‐scale capacitors because of efficient electron transfer from the one‐electron‐reduced POM to the excited singlet state of the perylene monoimide.
Hydrogenation of CC Multiple Bonds Mediated by [Pd(NHC)(PCy3)] (NHC=N‐Heterocyclic Carbene) under Mild Reaction Conditions
Authors: Jurčík Václav , Nolan Steven P. , Cazin Catherine S. J. 
Published: February 2009

AbstractN‐Heterocyclic carbenes do it again! [Pd(SIPr)(PCy3)] (1; SIPr=N,N′‐(bis(2,6‐diisopropylphenyl)imidazolidine), which is stable under H2, was shown to be a highly active catalyst for the hydrogenation of a wide range of alkenes and alkynes. Reactions proceed under mild conditions (relatively low Pd loading, RT, low pressures of H2) even when sterically hindered alkenes (tri‐ and tetra‐substituted) are used.magnified image
Pseudo P waves: A cause of diagnostic confusion in wide QRS tachycardia
Authors: Chapman P. D. , Wetherbee J. N. , Troup P. J. 
Published: February 2009

AbstractA patient with wide QRS tachycardia is described. His initial electrocardiogram revealed P waves in lead V1 that led to a diagnosis of supraventricular tachycardia. Subsequently, during an electrophysiology study, the tachycardia was reproduced and documented to be ventricular in origin. The P waves seen were actually part of the QRS complex and therefore pseudo P waves. The correct diagnosis of the arrhythmia allowed for more appropriate therapy for the patient. This case illustrates that pseudo P waves may be present on the surface electrocardiogram and confuse the diagnosis of wide QRS tachycardia.
Time sequence of anginal pain
Authors: Mattioli G. , Cioni G. , Andreoli C. 
Published: February 2009

AbstractWe studied 187 patients with angina at rest in order to evaluate the circadian rhythm of chest pain attacks. All subjects were followed for 7 days in absence of therapy (placebo period) and then with therapy (nifedipine, metoprolol, or isosorbide dinitrate). During the placebo period (1309 days) 1466 attacks were recorded, on an average of 1.1 per day. Most episodes occurred between 5 and 8 A.M. The incidence of chest pain attacks was much lower between 9 A.M. and 4 P.M. During the period with therapy, a reduction of painful episodes was observed, while the diurnal distribution remained unchanged. Furthermore, we studied the relationship between circadian distribution of anginal attacks and the extension of coronary damage in the 76 patients who underwent coronary angiography. Alterations of diurnal distribution of chest pain attacks were noted in subjects with normal coronary arteries and those with one‐vessel and two‐vessel disease. Patients with three‐vessel disease or left main coronary artery stenosis showed more uniform distribution of their attacks.
Normal sympathetic neural activity in patients with mitral valve prolapse
Authors: Lenders J. W. M. , Fast J. H. , Blankers J. , De BOO T. H. , Lemmens W. A. J. , Thien T. H. 
Published: February 2009

AbstractThe hemodynamic and neurohumoral responses to head‐up tilt and isometric exercise were studied in 14 mitral valve prolapse (MVP) patients with and 10 MVP patients without complaints and in 16 healthy control subjects. Plasma catecholamines at rest were not different between the three groups and neither were their changes during either test. The hemodynamic changes during head‐up tilt were not different between the three groups. The symptomatic MVP patients showed a lower rise in diastolic blood pressure (14.3±6.4%) than the controls (22.9±9.6%) (p<0.05) during isometric exercise. In view of the fact that the neurohumoral responses to both tests were the same for all groups, we cannot support the suggestions from other studies that MVP patients have an impaired or enhanced sympathetic tone. Moreover, since there were no differences between symptomatic and asymptomatic MVP patients it is doubtful whether the complaints of symptomatic MVP patients are related to a high sympathetic neural activity.
The surgical experience with annuloaortic ectasia at the medical university of south carolina
Authors: Clevenger F. W. , Crawford F. A. 
Published: February 2009

AbstractHemodynamically significant aortic insufficiency can result from dilitation of the aortic valve annulus in association with an ascending aortic aneurysm (annuloaortic ectasia). Controversy has centered around the optimal surgical management. This study evaluates the results of total replacement of the aortic valve and ascending thoracic aorta with a valved aortic prosthesis and reimplantation of the coronary arteries in a small series. In 7 patients with a mean preoperative New York Heart Association Classification (NYHAC) of III, there have been no operative or long‐term mortalities, and the average upgrade in NYHAC is 1.6. There have been no major complications or technical difficulties. The composite approach to the repair of patients with annuloaortic ectasia is described and advocated.
Appearance of T‐Wave inversions without raised serum enzyme activity in suspected acute myocardial infarction: Clinical outcome in relation to subendocardial infarction
Authors: Herlitz J. , HJALMARSON Å. 
Published: February 2009

AbstractIn 67 patients with a clinical history of suspected acute myocardial infarction (MI) who developed T‐wave inversions in standard ECG and had normal serum aspartate aminotransferase activity (possible MI) the clinical outcome was compared with that in patients fulfilling criteria for subendocardial infarction. Patients with possible MI had a lower mortality (p=0.02) and also a lower reinfarction rate (p=0.14) during the first 2 years as compared with those with subendocardial MI. Although patients with subendocardial MI had more problems with chest pain in the acute phase, angina pectoris occurred more frequently in patients with possible MI during a longer follow‐up period. Congestive heart failure occurred more frequently in patients with subendocardial MI during initial hospitalization, whereas treatment for heart failure appeared similar in the two groups during a longer follow‐up time. We conclude that the clinical course in patients with possible MI, here defined as chest pain and appearance of T‐wave inversions without elevation of serum enzyme activity, seems to differ from that in patients with subendocardial MI, particularly regarding long‐term survival and incidence of angina pectoris.
Anomalous origin of the right coronary artery arising from the circumflex artery
Authors: Tavernarakis A. , Voudris V. , Ifantis G. , Tsaganos N. 
Published: February 2009

AbstractA case of anomalous origin of the right coronary artery discovered among 3100 selective coronary arteriograms is described. This artery was arising from the circumflex artery. The position, distribution, and configuration of this coronary artery was as a normal right coronary artery, except that its origin was in the peripheral segment of the circumflex artery. This anomalous origin is very rare and seems not to give rise to any clinical significance.
Detection of spontaneous echocardiographic contrast within the left atrium by transesophageal echocardiography: spontaneous echocardiographic contrast
Authors: Erbel R. , Stern H. , Ehrenthal W. , Schreiner G. , Treese N. , Meyer J. , Krämer G. , Thelen M. , Schweizer P. 
Published: February 2009

AbstractTransesophageal echocardiography was performed in 314 patients over a period of 24 months using a 3.5 MHz phased‐array system fitted to the distal end of a conventional 12 mm endoscope. In 12 patients (2.6%) transesophageal echocardiography could not be performed because of adverse reaction to the gastroscopic procedure. Side effects were a transient A‐V block in one patient and asthmatic attack in another. Mitral valve lesions were found in 99 of 314 patients. In 9 of these 99 patients (11%), including 1 patient with mitral valve stenosis and sinus rhythm, 2 with atrial fibrillation, 3 with disc, and 3 with porcine mitral prosthesis, spontaneous echocardiographic contrast was found within the left atrium, described as faint echoes in 2 patients and dense echoes filling the whole left atrium and following turbulent flow in the other 7 patients. Only in 2 patients was left atrium shown to have additional echoes within its cavity in the four‐chamber view by transthoracic echocardiography. Signs of cerebral emboli were found in 5 of 9 patients and of peripheral embolism in 3 of 9 patients. Their mechanism seems to involve red cell aggregation, which is greatest at low flow velocity such as in dilated left atria in the case of mitral valve stenosis or prosthesis. The additional effect of platelet aggregation must be discussed because increased platelet aggregation was detected in all patients with spontaneous echocardiographic contrast. Transesophageal echocardiography seems to be of great diagnostic value in patients with mitral valve lesions and cerebral and peripheral embolism, giving new insight into the pathophysiologic mechanism and possibly improving the therapeutic approach in the near future.