bluuebunny/crossref_metadata_2025_split huggingface dataset:
National audit of the use of surgery and radiological embolization after failed endoscopic haemostasis for non-variceal upper gastrointestinal bleeding
Authors: Jairath V , Kahan B C , Logan R F A , Hearnshaw S A , Dore C J , Travis S P L , Murphy M F , Palmer K R 
Published: September 2012

AbstractBackgroundFollowing non-variceal upper gastrointestinal bleeding (NVUGIB), 10–15 per cent of patients experience further bleeding. Although surgery has been the traditional salvage therapy, there is renewed interest in transcatheter arterial embolization (TAE). This study examined the use, clinical characteristics and outcomes of patients receiving salvage surgery or TAE after failed endoscopic haemostasis for NVUGIB.MethodsA UK national audit of upper gastrointestinal bleeding was undertaken in May and June 2007. A logistic regression model was used to identify clinical predictors of endoscopic failure.ResultsData were analysed from 4478 patients involving 212 UK centres. Some 533 (11·9 per cent) experienced further bleeding, of whom 163 (30·6 per cent) proceeded to salvage therapy with surgery (97), TAE (60) or both (6). Among surgical patients (mean age 71 years), 66·0 per cent (68 of 103) had a Rockall score of at least 3 and emergency surgery was carried out between midnight and 08.00 hours in 21 per cent, with a consultant surgeon present in 89 per cent of operations. Some 9 per cent of patients had further bleeding after TAE, resulting in later surgery. The mortality rate was 29 per cent after surgery, 10 per cent after TAE and 23·2 per cent among those with further bleeding after the index endoscopy that was managed by endoscopy alone. The strongest predictors of endoscopic failure were coagulopathy (odds ratio 3·27, 95 per cent confidence interval 2·37 to 4·53) and a haemoglobin level of 10 g/dl or less (odds ratio 2·22, 1·71 to 2·87, for haemoglobin 8–10 g/dl).ConclusionSalvage surgery and embolization are required in fewer than 4 per cent of patients with NVUGIB. The high postoperative mortality rate, reflecting age, co-morbidity and severity of bleeding, warrants a prospective study to establish the effectiveness and safety of TAE as an alternative to surgery in the management of bleeding after failure of endoscopic therapy.
Identification of isoquercitrin metabolites produced by human intestinal bacteria using UPLC‐Q‐TOF/MS
Authors: Lu Linling , Qian Dawei , Yang Jing , Jiang Shu , Guo Jianming , Shang Er‐xin , Duan Jin‐ao 
Published: September 2012

ABSTRACTIn this paper, ultraperformance liquid chromatography/quadrupole time‐of‐flight mass spectrometry (UPLC‐Q‐TOF/MS) and the MetaboLynx™ software combined with mass defect filtering were applied to identity the metabolites of isoquercitrin using an intestinal mixture of bacteria and 96 isolated strains from human feces. The human incubated samples collected for 72 h in the anaerobic incubator and extracted with ethyl acetate were analyzed by UPLC‐Q‐TOF/MS within 10 min. The parent compound and five metabolites were identified by eight isolated strains, including Bacillus sp. 17, Veillonella sp. 23 and 32 and Bacteroides sp. 40, 41, 56, 75 and 88 in vitro. The results indicate that quercetin, acetylated isoquercitrin, dehydroxylated isoquercitrin, hydroxylated quercetin and hydroxymethylated quercetin are the major metabolites of isoquercitrin. Furthermore, a possible metabolic pathway for the biotransformation of isoquercitrin was established in intestinal flora. This study will be helpful for understanding the metabolic route of isoquercitrin and the role of different intestinal bacteria in the metabolism of natural compounds. Copyright © 2012 John Wiley & Sons, Ltd.
Highly Selective Bimetallic Pt‐Cu/Mg(Al)O Catalysts for the Aqueous‐Phase Reforming of Glycerol
Authors: Boga Dilek A. , Oord Ramon , Beale Andrew M. , Chung Young‐Min , Bruijnincx Pieter C. A. , Weckhuysen Bert M. 
Published: September 2012

AbstractMonometallic Pt and bimetallic Pt‐Cu catalysts supported on Mg(Al)O mixed oxides, obtained by calcination of the corresponding layered double hydroxides (LDHs), were prepared and tested in the aqueous‐phase reforming (APR) of glycerol. The effect of the Mg/Al ratio and calcination temperature of the LDH support, as well as the effect of varying Pt and Cu amounts on glycerol reforming, was investigated. The use of a basic support increases the selectivity to hydrogen and the use of a Pt‐Cu bimetallic catalyst results in a decrease in alkane formation. The 0.9 wt. % Pt‐0.4 wt. % Cu/Mg(Al)O_2.95 catalyst system with an Mg(Al)O mixed oxide support obtained by the calcination of the corresponding LDH material with Mg/Al ratio of 2.95 at 673 K, showed higher hydrogen selectivity (55.3 %) and lower methane production (1.9 %) after 5 h reaction than the benchmark Pt/Al2O3 catalyst (49.4 % and 5.6 %, respectively). Catalyst characterization by extended X‐ray absorption fine structure (EXAFS) spectroscopy showed a bimetallic interaction between Pt and Cu. The bimetallic interaction is thought to be responsible for the lowered methane formation and, ultimately, the high hydrogen selectivity observed.
Solid‐State 73Ge NMR Spectroscopy of Simple Organogermanes
Authors: Hanson Margaret A. , Sutrisno Andre , Terskikh Victor V. , Baines Kim M. , Huang Yining 
Published: September 2012

AbstractGermanium‐73 is an extremely challenging nucleus to examine by NMR spectroscopy due to its unfavorable NMR properties. Through the use of an ultrahigh (21.1 T) magnetic field, a systematic study of a series of simple organogermanes was carried out. In those cases for which X‐ray structural data were available, correlations were drawn between the NMR parameters and structural metrics. These data were combined with DFT calculations to obtain insight into the structures of several compounds with unknown crystal structures.
Organocatalyzed Enantioselective Desymmetrization of Diols in the Preparation of Chiral Building Blocks
Authors: Díaz‐de‐Villegas María D. , Gálvez José A. , Badorrey Ramón , López‐Ram‐de‐Víu M. Pilar 
Published: October 2012

AbstractDesymmetrization of diols is a powerful tool to the synthesis of chiral building blocks. Among the different approaches to perform discrimination between both enantiotopic hydroxyl groups, the organocatalytic approach has gained importance in the last years. A diverse range of organocatalysts has been used to efficiently promote this enantioselective transformation and this Minireview examines the different contributions in this field.
Limitation of Discharge Capacity and Mechanisms of Air‐Electrode Deactivation in Silicon–Air Batteries
Authors: Jakes Peter , Cohn Gil , Ein‐Eli Yair , Scheiba Frieder , Ehrenberg Helmut , Eichel Rüdiger‐A. 
Published: October 2012

AbstractThe electrocatalytical process at the air cathode in novel silicon–air batteries using the room‐temperature ionic liquid hydrophilic 1‐ethyl‐3‐methylimidazolium oligofluorohydrogenate [EMI⋅2.3 HF⋅F] as electrolyte and highly doped silicon wafers as anodes is investigated by electrochemical means, X‐ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) spectroscopy. The results obtained by XPS and EPR provide a model to describe the limited discharge capacity by means of a mechanism of air‐electrode deactivation. In that respect, upon discharge the silicon‐air battery′s cathode is not only blocked by silicon oxide reduction products, but also experiences a major modification in the MnO2 catalyst nature. The proposed modification of the MnO2 catalyst by means of a MnF2 surface layer greatly impacts the Si–air performance and describes a mechanism relevant for other metal–air batteries, such as the lithium–air. Moreover, the ability for this deactivation layer to form is greatly impacted by water in the electrolyte.
Rainfall seasonality and pest pressure as determinants of tropical tree species' distributions
Authors: Baltzer Jennifer L. , Davies Stuart J. 
Published: September 2012

AbstractDrought and pests are primary abiotic and biotic factors proposed as selective filters acting on species distributions along rainfall gradients in tropical forests and may contribute importantly to species distributional limits, performance, and diversity gradients. Recent research demonstrates linkages between species distributions along rainfall gradients and physiological drought tolerance; corresponding experimental examinations of the contribution of pest pressure to distributional limits and potential interactions between drought and herbivory are limited. This study aims to quantitate differential performance and herbivory as a function of species range limits across a climatic and floristic transition in Southeast Asia. Khao Chong Botanical Garden, Thailand and Pasoh Forest Reserve, Malaysia straddle the Kangar‐Pattani Line. A reciprocal transplantation across a seasonality gradient was established using two groups of species (“widespread” taxa whose distributions include seasonally dry forests and “aseasonal” taxa whose distributions are limited to aseasonal forests). Growth, biomass allocation, survival, and herbivory were monitored for 19 months. Systematic differences in performance were a function of species distribution in relation to rainfall seasonality. In aseasonal Pasoh, aseasonal species had both greater growth and survivorship than widespread species. These differences were not a function of differential herbivory as widespread and aseasonal species experienced similar damage in the aseasonal forest. In seasonally dry Khao Chong, widespread species showed higher survivorship than aseasonal species, but these differences were only apparent during drought. We link this differential performance to physiological mechanisms as well as differential tolerance of biotic pressure during drought stress. Systematic decreases in seedling survival in aseasonal taxa during drought corresponded with previously documented physiological differences and may be exacerbated by herbivore damage. These results have important implications for tropical diversity and community composition in light of predicted increases in the frequency and severity of drought in hyperdiverse tropical forests.
Acclimation and interaction between drought and elevated UV‐B in A. thaliana: Differences in response over treatment, recovery and reproduction
Authors: Comont David , Winters Ana , Gwynn‐Jones Dylan 
Published: September 2012

AbstractHere, a factorial experiment was used to investigate the interactive effects of a UV‐B episode and concurrent progressive drought on the growth, chemistry, and reproductive success of A. thaliana. Both drought and UV‐B negatively affected rosette growth, although UV‐B had the greater effect. Acclimation to UV‐B involved adjustment of leaf morphology, while drought induced accumulation of soluble sugars and phenolics. All plants recovered from treatments, but the cost of recovery was a developmental delay resulting in alteration in phenological timings. Combined treatments interacted causing additive negative effects on growth following exposure. This may be linked with inhibition of soluble sugar accumulation by UV‐B, restricting the capacity for osmotic adjustment in response to drought. Following cessation of treatments, relative growth rate (RGR) and net assimilation rate (NAR) were significantly stimulated in plants treated with combined drought and UV‐B. This interaction alleviated subsequent impacts of elevated UV‐B on silique yield and reproductive timings. This study demonstrates the potential for interaction between these two common environmental factors. Furthermore, it shows the changeable nature of these interactions over the course of exposure and recovery through to reproduction, highlighting the need for sustained assessment of such interactions over a plant's lifecycle.
Strong Organic Bases as Building Blocks of Mesoporous Hybrid Catalysts for C–C Forming Bond Reactions
Authors: Gianotti Enrica , Diaz Urbano , Velty Alexandra , Corma Avelino 
Published: September 2012

Abstract1,8‐Bis(tetramethylguanidino)naphthalene (TMGN), a neutral organic base that combines the properties of guanidine and the properties of proton sponges, was used as a building block to produce organic–inorganic silica‐based mesoporous hybrids with strong basic properties. The TMGN‐based mesoporous hybrids (TMGN/SiO2) were prepared by a sol–gel route working at a neutral pH and low temperatures, which avoided the use of SDAs. TMGN has been modified in order to have two terminal reactive silyl groups able to perform co‐condensation with a conventional organosilane (TMOS) used as a silicon source. This synthesis has allowed us to directly introduce the unmodified, functionalized TMGN as part of the walls of the mesoporous silica by a one‐pot synthesis. TMGN/SiO2 hybrid materials present excellent catalytic properties for C–C bond forming reactions: Knoevenagel, Henry (nitroaldol), and Claisen–Schmidt condensations. The activity of the hybrid materials is higher than that of the counterpart homogeneous catalyst.
Cycloaddition Reactions of Propiolamidinium Salts
Authors: Weingärtner Werner , Maas Gerhard 
Published: September 2012

AbstractThermal and microwave‐assisted [3+2] cycloadditions between differently substituted propiolamidinium tetraphenylborates 3a–d and N‐methyl‐C‐phenylnitrone, benzyl azide, and N‐(3‐azidopropyl)phthalimide were studied. The activation parameters of the [3+2] cycloaddition between alkyne 3a and benzyl azide were determined. A Diels–Alder reaction between the terminal alkyne 3a and cyclopentadiene could be achieved with the aid of microwave activation. The reaction between 3a and triphenylphosphorane imine provides the β,β‐bis(dimethylamino)vinylphosphonium salt 21, which might or might not have been formed through an initial [2+2] cycloaddition reaction.
Geotechnical experience from the hydroshield drives on contracts H 3‐4 and H 8 in the Lower Inn Valley / Geotechnische Erkenntnisse aus den Hydroschildvortrieben der Baulose H 3‐4 und H 8 im Unterinntal
Authors: Köhler Manfred , Maidl Ulrich , Scholz Marcus , Wendl Katharina 
Published: October 2012

AbstractTwo tunnels were driven in the Lower Inn valley in the years 2007 to 2009 using almost identical mixshields (∅︁ 13.03 m) under difficult geotechnical conditions. The tunnelling works were monitored and recorded permanently in real time, from which information can be gained about the system of shield machine and surrounding ground. The documentation of the ground conditions was undertaken by geologists working for the client. The continuous documentation of tunnelling included reporting on the excavated material as the drive was underway and the documentation of face conditions during compressed air interruptions. The combination of recorded machine data and the geological documentation of the tunnel drive provides an extensive data basis, whose evaluation shows the complex relationships of the various tunnelling parameters.Im Unterinntal wurden in den Jahren 2007 bis 2009 zwei Tunnel mit fast baugleichen Mixschilden (∅︁ 13, 03 m) unter schwierigen geotechnischen Randbedingungen aufgefahren. Die Vortriebsarbeiten wurden permanent in Echtzeit überwacht und aufgezeichnet, aus den gesammelten Daten ergaben sich Einblicke in das Systemverhalten Schildmaschine/Baugrund. Die Dokumentation der Baugrundverhältnisse wurde von Geologen des Bauherrn vorgenommen. Die kontinuierliche Vortriebsdokumentation umfasste die Begutachtung des Ausbruchmaterials während des laufenden Vortriebs sowie die Dokumentation der Ortsbrustverhältnisse während der Drucklufteinstiege. Die Kombination aus aufgezeichneten Maschinendaten und der geologischen Vortriebsdokumentation ergibt eine umfassende geotechnische Datenbasis, deren Auswertung die komplexen Zusammenhänge der verschiedenen Vortriebsparameter aufzeigt.
Performance of Compliance and Persistence Measures in Predicting Clinical and Economic Outcomes Using Administrative Data from German Sickness Funds
Authors: Frey Simon , Stargardt Tom 
Published: October 2012

Study ObjectiveTo compare the performance of various compliance and persistence measures in predicting schizophrenia‐related hospitalization rates and inpatient costs.DesignRetrospective, nonrandomized cohort study.Data SourcePrescription claims databases from three German sickness funds (public health insurance programs).PatientsA total of 1484 patients who were hospitalized in 2003 for a schizophrenia‐related episode and subsequently received long‐term antipsychotic pharmacotherapy.Measurements and Main ResultsData on age, sex, schizophrenia, prescription drugs, hospitalizations, and inpatient expenditures were collected for each patient from the three German sickness funds. Refill compliance measures based on single‐interval availability and multiple‐interval availability, as well as refill persistence, were calculated for each patient over 1 year. Ten measurement variables were compared with respect to their performance in predicting disease‐related hospitalization and inpatient expenditure, using multivariate logistic regression and gamma regression, respectively. C‐statistics were calculated to determine each measure's predictive performance. Likelihood ratio tests showed that inclusion of compliance and persistence measures significantly improved (p<0.05) outcomes prediction in 6 of 10 hospitalization models and in 3 of 10 inpatient cost models compared with a baseline model that included only age, sex, and disease severity covariates. Refill compliance as a continuous variable of drug persistence, including transfer of oversupplies into subsequent periods, performed best in predicting hospitalization (C = 0.669). Availability ratios, capped at 100%, were superior to default availability ratios in predicting hospitalization. Allowing for cross‐period carryover improved the discriminatory performance of the persistence models.ConclusionRefill persistence measures appear sufficiently flexible to account for hospitalizations common in schizophrenia and other psychiatric diseases. A continuous refill persistence measure should be used to assess compliance in psychiatric conditions when working with administrative data.
Effects of recombinant human bone morphogenic protein‐2 and human bone marrow‐derived stromal cells on in vivo bone regeneration of chitosan–poly(ethylene oxide) hydrogel
Authors: Jo Seongyeon , Kim Sumi , Cho Tae Hyung , Shin Eunkyong , Hwang Soon Jung , Noh Insup 
Published: September 2012

AbstractIn vivo bone regeneration of chitosan–poly(ethylene oxide) (PEO) hydrogel in rat carlvarial defects was evaluated by using both human bone marrow‐derived stromal cells (hMSCs) and recombinant human bone marrow protein‐2 (rhBMP‐2) for 4 and 8 weeks. In situ chitosan–PEO hydrogel was fabricated by mixing the precursor solutions of both chitosan‐acrylate and PEO‐thiol. Fabrication of the injectable hydrogels was modulated from within a minute to hours by controlling the temperature and pHs of the precursor solution. Gel swellings were dependent on the conditions of pHs and temperatures of the precursor solutions, showing higher gel swelling in basic water than in either acidic or neutral water. The compression strengths and in vitro degradation of hydrogels were also evaluated by controlling the concentrations of both precursor solutions and lysozyme, respectively, by referencing to the morphology of the control hydrogel with no enzyme added. Hydrogels showed sustained release of rhodamine‐B over time. After implantation of the injectable hydrogels in rat calvarial defects for 4 and 8 weeks, in vivo bone regenerations were compared with by evaluating the degrees of new bone formations with Soft X‐ray, microcomputed tomography, and histological stainings of hematoxylin and eosine Y and Masson's trichrome. Degrees of in vivo bone regeneration were controlled by encapsulating in advance either hMSCs, rhBMP‐2, or both in the precursor solutions of the hydrogel. The defect implanted with hydrogel only showed higher amount of bone tissue regeneration than that of the control defect site. The defect sites with hydrogel containing both hMSCs and rhBMP‐2 demonstrated highest amount of bone tissue regeneration among the samples. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 892–901, 2013.
Type 2 diabetes and bone
Authors: Leslie William D , Rubin Mishaela R , Schwartz Ann V , Kanis John A 
Published: September 2012

Abstract
There is a growing body of research showing that diabetes is an independent risk factor for fracture. Type 2 diabetes (T2D), which predominates in older individuals and is increasing globally as a consequence of the obesity epidemic, is associated with normal or even increased dual-energy x-ray absorptiometry (DXA)-derived areal bone mineral density (BMD). Therefore, the paradoxical increase in fracture risk has led to the hypothesis that there are diabetes-associated alterations in material and structural properties. An overly glycated collagen matrix, confounded by a low turnover state, in the setting of subtle cortical abnormalities, may lead to compromised biomechanical competence. In current clinical practice, because BMD is central to fracture prediction, a consequence of this paradox is a lack of suitable methods, including FRAX, to predict fracture risk in older adults with T2D. The option of adding diabetes to the FRAX algorithm is appealing but requires additional data from large population-based cohorts. The need for improved methods for identification of fracture in older adults with T2D is an important priority for osteoporosis research. © 2012 American Society for Bone and Mineral Research.
Accurate integration over atomic regions bounded by zero‐flux surfaces
Authors: Polestshuk Pavel M. 
Published: September 2012

AbstractThe approach for the integration over a region covered by zero‐flux surface is described. This approach based on the surface triangulation technique is efficiently realized in a newly developed program TWOE. The elaborated method is tested on several atomic properties including the source function. TWOE results are compared with those produced by using well‐known existing programs. Absolute errors in computed atomic properties are shown to range usually from 10−6 to 10−5 au. The demonstrative examples prove that present realization has perfect convergence of atomic properties with increasing size of angular grid and allows to obtain highly accurate data even in the most difficult cases. It is believed that the developed program can be bridgehead that allows to implement atomic partitioning of any desired molecular property with high accuracy. © 2012 Wiley Periodicals, Inc.
Esters flash point prediction using artificial neural networks
Authors: Astray Gonzalo , Gálvez Juan F. , Mejuto Juan C. , Moldes Oscar A. , Montoya Iago 
Published: September 2012

AbstractIn this article, an artificial neural network to predict the flash point of 95 esters was implemented. Four variables were used for its development. A neural network with 4‐5‐8‐5‐1 topology was encountered to gain the best agreement of the experimental results with those predicted (square correlation coefficient (R2) and root mean square error were 0.99 and 5.46 K for the training phase and 0.96 and 13.02 K for the testing set). © 2012 Wiley Periodicals, Inc.