bluuebunny/crossref_metadata_2025_split huggingface dataset:
Revision komplexer supramolekularer Polymerisation unter kinetischer und thermodynamischer Kontrolle
Authors: Matern Jonas , Dorca Yeray , Sánchez Luis , Fernández Gustavo 
Published: July 2019

AbstractPathway‐Complexity, hierarchische Organisation, Außer‐Equilibrium‐ und metastabile oder kinetisch gefangene Spezies sind Begriffe die in jüngsten, hochqualitativen Publikationen im Feld der supramolekularen Polymere häufig verwendet werden. Oftmals sind die Terminologien, die die verschiedenen Selbstassemblierungspfade, die beteiligten Spezies und deren Beziehung sowie relativen Stabilitäten zueinander beschreiben, nicht trivial. In der Literatur sind häufig verschiedene Begriffe und Klassifizierungen zu finden, in vielen Fällen jedoch ohne klare Definitionen oder Richtlinien wie sie zu benutzen sind oder wie sie experimentell unterschieden werden können. Ziel dieses Kurzaufsatzes ist es, die existierenden Konzepte mithilfe jüngster Literatur zu klassifizieren, differenzieren und zu korrelieren. Dadurch soll der Leser eine generelle Einsicht in thermodynamische und kinetische Aspekte komplexer supramolekularer Polymerisationsprozesse erhalten. Ein gutes Verständnis dieser Begriffe und Konzepte sollte dazu beitragen, neue, komplexe, funktionale Materialien zu erschaffen.
Quantifying the Interdependence of Metal–Ligand Covalency and Bond Distance Using Ligand K‐edge XAS
Authors: Lee Kyounghoon , Blake Anastasia V. , Donahue Courtney M. , Spielvogel Kyle D. , Bellott Brian J. , Daly Scott R. 
Published: July 2019

AbstractBond distance is a common structural metric used to assess changes in metal–ligand bonds, but it is not clear how sensitive changes in bond distances are with respect to changes in metal–ligand covalency. Here we report ligand K‐edge XAS studies on Ni and Pd complexes containing different phosphorus(III) ligands. Despite the large number of electronic and structural permutations, P K‐edge pre‐edge peak intensities reveal a remarkable correlation that spectroscopically quantifies the linear interdependence of covalent M−P σ bonding and bond distance. Cl K‐edge studies conducted on many of the same Ni and Pd compounds revealed a poor correlation between M−Cl bond distance and covalency, but a strong correlation was established by analyzing Cl K‐edge data for Ti complexes with a wider range of Ti−Cl bond distances. Together these results establish a quantitative framework to begin making more accurate assessments of metal–ligand covalency using bond distances from readily‐available crystallographic data.
Synergistic effect of CaO and MgO addition on coal ash fusibility in a reducing atmosphere
Authors: Wu Chengli , Xin Yu , Liu Xiang , Li Hanxu , Jiao Facun 
Published: July 2019

AbstractDuring coal gasification in entrained‐flow slagging gasifiers, the addition of additives is a promising method to improve coal ash fusibility. In some cases, mixed additives are more effective in decreasing ash fusibility than single additive addition with the same content added. However, mechanisms of mixed additive addition for improving ash melting are scarce. In this study, the effect of CaO, MgO, and their mixtures on the ash flow temperature (FT) of Chinese bituminous coal was investigated. The results show that the single addition of CaO or MgO influenced the ash FT of the test coal sample. The addition of CaO and MgO mixture synergistically decreased the ash FT relative to their single addition. When the ratio of CaO to MgO was 5:5 (mass ratio) in the mixture, the FT decreased to 1297°C, which is 69°C and 110°C lower than that of the single addition of CaO and MgO, respectively. The formation of a low‐temperature eutectic from the interactions between anorthite and olivine caused such synergistic effects.
Thermal and mechanical enhancement of styrene–butadiene rubber by filling with modified anthracite coal
Authors: Tan Jinlong , Cheng Hongzhi , Wei Lubin , Gui Xiahui 
Published: July 2019

ABSTRACTAnthracite is the highest rank of coal with a layered structure similar to that of graphite. Here, styrene–butadiene rubber/modified anthracite (MA) composites were prepared and analyzed. The microstructure and dispersion of the anthracite were improved by ball milling with the modifier bis‐(γ‐triethoxysilylpropyl)‐tetrasulfide (KH‐Si69). The particle size of the modified coal was decreased significantly to ~3 μm, while surface interactions with the modifier yielded enhanced lamellar morphology and hydrophobic surfaces. The anthracite lamellae were well dispersed in the rubber matrix, providing good reinforcement; the tensile strength of the composite exceeded that of a composite with carbon black (CB) N660 filler (16.65 vs. 14.68 MPa). Moreover, low‐level CB or silica compositing further promoted the dispersion of coal particles in the rubber, effectively enhancing the mechanical reinforcement behavior of the coal particles as well as the thermal stability of the rubber composite. Notably, it led to a 10.63% improvement in tensile strength and a 9.96 °C increase in the 5% mass loss temperature compared to the composite with a single MA filler. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48203.
Two Stable Heterometal‐MOFs as Highly Efficient and Recyclable Catalysts in the CO2 Coupling Reaction with Aziridines
Authors: Kang Xiao‐Min , Yao Lin‐Hong , Jiao Zhuo‐Hao , Zhao Bin 
Published: July 2019

AbstractTwo stable heterometal‐organic frameworks, {Na[LnCo(DATP)2(Ac)(H2O)](NO3)⋅DMA⋅11 H2O}n (Ln=Er(1) and Yb(2)), have been prepared with H2DATP (4′‐(3,5‐dicarboxyphenyl)‐2,2′:6′,2′′′‐terpyridine) as organic building block. These two isostructural compounds featuring two‐dimensional layer architectures possess outstanding thermal stabilities and excellent chemical stabilities in common organic solvents and different acid/base solutions with pH range changing from 1 to 13. Moreover, compounds 1 and 2 serving as heterogeneous catalysts can efficiently catalyse the CO2 fixation reaction with various aziridines to result in corresponding oxazolidinones at 70 °C. Importantly, a good recyclable performance of 1 for at least 10 cycles is observed based on the experimental results, which are further confirmed by PXRD, TGA and ICP analyses.
Impact of El Niño and Southern Oscillation on the summer precipitation over Northwest China
Authors: Lu Bo , Li Haiyan , Wu Jie , Zhang Taixi , Liu Jing , Liu Bao , Chen Ying , Baishan Jiazila 
Published: July 2019

AbstractUsing the reanalysis data and local weather station data, the relationship between El Niño and Southern Oscillation (ENSO) and the summer precipitation over Northwest China (SPNWC) is investigated. A pronounced rainfall response is observed in post‐ENSO summer, especially over North Xinjiang and Yili River valley. A possible mechanism is proposed for such a seasonal lagged impact. El Niño could induce Indian Ocean warming that persists into boreal spring and summer although El Niño itself has dissipated. The warmer Indian Ocean sea surface temperature (SST) would heat the tropospheric atmosphere and elevate the tropical geopotential height at the upper level. As a result, the South Asian High (SAH) exhibits a southward extension due to the increasing geopotential height in its southern flank. A southward displacement of subtropical jet is evident associated with such SAH shift, which further induces a barotropic low pressure anomaly over central Asia. Meanwhile, associated with the southward displacement of subtropical jet, the water vapor from tropical Indian Ocean tends to transport across Iranian Plateau and bring wet and warm air into central Asia. The resultant convergence of water vapor with cold and dry air from high latitude leads to the observed rainfall anomaly to the south and east of Balkhash Lake, explaining the lagged relationship between ENSO and SPNWC. Our results have potential applications on the seasonal prediction of SPNWC.
The Impact of pH on Catalytically Critical Protein Conformational Changes: The Case of the Urease, a Nickel Enzyme
Authors: Mazzei Luca , Cianci Michele , Benini Stefano , Ciurli Stefano 
Published: July 2019

AbstractUrease uses a cluster of two NiII ions to activate a water molecule for urea hydrolysis. The key to this unsurpassed enzyme is a change in the conformation of a flexible structural motif, the mobile flap, which must be able to move from an open to a closed conformation to stabilize the chelating interaction of urea with the NiII cluster. This conformational change brings the imidazole side chain functionality of a critical histidine residue, αHis323, in close proximity to the site that holds the transition state structure of the reaction, facilitating its evolution to the products. Herein, we describe the influence of the solution pH in modulating the conformation of the mobile flap. High‐resolution crystal structures of urease inhibited in the presence of N‐(n‐butyl)phosphoric triamide (NBPTO) at pH 6.5 and pH 7.5 are described and compared to the analogous structure obtained at pH 7.0. The kinetics of urease in the absence and presence of NBPTO are investigated by a calorimetric assay in the pH 6.0–8.0 range. The results indicate that pH modulates the protonation state of αHis323, which was revealed to have pKa=6.6, and consequently the conformation of the mobile flap. Two additional residues (αAsp224 and αArg339) are shown to be key factors for the conformational change. The role of pH in modulating the catalysis of urea hydrolysis is clarified through the molecular and structural details of the interplay between protein conformation and solution acidity in the paradigmatic case of a metalloenzyme.
Microtubule nucleation in the cytoplasm of developing cortical neurons and its regulation by brain‐derived neurotrophic factor
Authors: Yamada Mimori , Hayashi Kensuke 
Published: July 2019

AbstractThe centrosomes of neurons do not nucleate microtubules (MTs). It is not well known where MTs are nucleated in neurons. We performed MT regrowth experiments in primary cultured cortical neurons from mice. After cold‐nocodazole depolymerization of MTs in neurons at 3 days in vitro (DIV), we observed numerous short MTs that regenerated in the cytoplasm; they were roughly equal in length and randomly oriented. Gamma‐tubulin and MZT2 were detected at one end of these MTs, indicating that the short MTs were nucleated by γ‐tubulin‐ring complexes; the Golgi apparatus was not the origin site of their nucleation. The ratio of MT‐regenerating cells, the density of regenerated MTs, and their lengths decreased at 7 DIV. Pretreatment of neurons with protein‐kinase inhibitors, K‐252a, staurosporine, or H7 diminished the length of the regenerated MTs, while pretreatment of neurons with brain‐derived neurotrophic factor increased the length of regenerated MTs. These results support the idea that short MTs with mixed orientations are transiently generated in the cytoplasm of differentiating neurons, and that they are possibly transported into dendrites to provide seeds for MTs with mixed polarity.
Chemical Bonding from the Statistics of the Electron Distribution
Authors: Pendás Ángel Martín , Francisco Evelio 
Published: July 2019

AbstractAn introduction to the theory of chemical bonding from the point of view of the statistics of the electron distribution is presented. When atoms bind to form a molecule, their originally fixed number of electrons ceases to be a well‐defined observable, and this implies that their in‐the‐molecule electron populations fluctuate. If a chemically meaningful definition of an atom in a molecule is assumed, the probabilities of finding a given number of electrons in each of the atoms comprising the molecule can be computed. We show in this review how the complete electron distribution function (EDF) can be used to reconstruct the basic concepts and quantities used in chemical bonding without recourse to the orbital paradigm. From the statistical point of view, which inherits Born's probabilistic interpretation of quantum mechanics, a set of atoms are bonded when their electron populations are mutually dependent. We quantify this statistical dependence by the cumulant moments of the EDF, which provide a consistent description of both two‐ and multi‐center bonding. Particular attention is paid to building EDFs from model wavefunctions. With this, a simple bridge with orbital thinking is built. The statistical interpretation allows to easily classify all possible bonds of a given kind. We show that there are vast unexplored territories that should receive due consideration. Although building EDFs from models is easy and very instructive, the contrary is considerably more difficult. Recipes to extract chemical information from computed EDFs are also reviewed and, in all the cases, simple toy systems are used to show how the methodology works, allowing non‐experts to follow easily the presentation.
Iron–PNP‐Pincer‐Catalyzed Transfer Dehydrogenation of Secondary Alcohols
Authors: Budweg Svenja , Wei Zhihong , Jiao Haijun , Junge Kathrin , Beller Matthias 
Published: July 2019

AbstractInvited for this month's cover is the group of Matthias Beller at the Leibniz‐Institute for Catalysis in Rostock. The image illustrates the catalytic dehydrogenation of secondary alcohols to the corresponding ketones using iron‐based pincer complexes. The Communication itself is available at 10.1002/cssc.201900308.
The environmental and genetic determinants of chick telomere length in Tree Swallows (Tachycineta bicolor)
Authors: Belmaker Amos , Hallinger Kelly K. , Glynn Rebbeca A. , Winkler David W. , Haussmann Mark F. 
Published: July 2019

AbstractConditions during early life can have dramatic effects on adult characteristics and fitness. However, we still know little about the mechanisms that mediate these relationships. Telomere shortening is one possibility. Telomeres are long sequences of DNA that protect the ends of chromosomes. They shorten naturally throughout an individual's life, and individuals with short telomeres tend to have poorer health and reduced survival. Given this connection between telomere length (TL) and fitness, natural selection should favor individuals that are able to retain longer telomeres for a greater portion of their lives. However, the ability of natural selection to act on TL depends on the extent to which genetic and environmental factors influence TL. In this study, we experimentally enlarged broods of Tree Swallows (Tachycineta bicolor) to test the effects of demanding early‐life conditions on TL, while simultaneously cross‐fostering chicks to estimate heritable genetic influences on TL. In addition, we estimated the effects of parental age and chick sex on chick TL. We found that TL is highly heritable in Tree Swallow chicks, and that the maternal genetic basis for TL is stronger than is the paternal genetic basis. In contrast, the experimental manipulation of brood size had only a weak effect on chick TL, suggesting that the role of environmental factors in influencing TL early in life is limited. There was no effect of chick sex or parental age on chick TL. While these results are consistent with those reported in some studies, they are in conflict with others. These disparate conclusions might be attributable to the inherent complexity of telomere dynamics playing out differently in different populations or to study‐specific variation in the age at which subjects were measured.
Filling the “data gap”: Using paleoecology to investigate the decline of Najas flexilis (a rare aquatic plant)
Authors: Bishop Isabel J. , Bennion Helen , Sayer Carl D. , Patmore Ian R. , Yang Handong 
Published: July 2019

In the absence of long‐term monitoring records, paleoecology can be used to extend knowledge of species and community ecology into the past. The rare and declining aquatic plant Najas flexilis is a priority species for conservation across Europe, and is an ideal candidate for paleoecological study; not only are historical records of the plant sparse, but its seeds are commonly found and well preserved in lake sediment cores. In this study, we investigate the timing and causes of decline at two UK sites at which N. flexilis has recently become extinct: Esthwaite Water (England) and Loch of Craiglush (Scotland). For both sites, multiple paleoecological indicators and available historical biological records and monitoring data are compared to numbers of N. flexilis seeds enumerated in dated sediment cores representing the last 150 years. At Esthwaite Water, N. flexilis seeds were found in abundance in association with indicators of a clear, oligo‐mesotrophic, mildly alkaline lake. Eutrophication led to the disappearance of N. flexilis in the 1980s. By contrast, far fewer N. flexilis seeds were found in a core from Loch of Craiglush, and the current period of N. flexilis absence was found to be one of several over the last 100 years. Species represented in cores taken from Loch of Craiglush were indicative of slightly more acidic conditions than Esthwaite Water. Given that N. flexilis favours circumneutral to alkaline conditions, it is possible that Loch of Craiglush has not always been favourable for the plant. These findings have important implications for future conservation efforts, particularly at Esthwaite Water where they suggest that recent failed attempts to reintroduce the species may have been premature. More generally, this study demonstrates the value of paleoecological techniques as a means to provide the long‐term context that is often missing from conservation planning and management.
Noninvasive Tests Accurately Identify Advanced Fibrosis due to NASH: Baseline Data From the STELLAR Trials
Authors: Anstee Quentin M. , Lawitz Eric J. , Alkhouri Naim , Wong Vincent Wai‐Sun , Romero‐Gomez Manuel , Okanoue Takeshi , Trauner Michael , Kersey Kathryn , Li Georgia , Han Ling , Jia Catherine , Wang Lulu , Chen Guang , Subramanian G. Mani , Myers Robert P. , Djedjos C. Stephen , Kohli Anita , Bzowej Natalie , Younes Ziad , Sarin Shiv , Shiffman Mitchell L. , Harrison Stephen A. , Afdhal Nezam H. , Goodman Zachary , Younossi Zobair M. 
Published: July 2019

Accurate noninvasive tests (NITs) are needed to replace liver biopsy for identifying advanced fibrosis caused by nonalcoholic steatohepatitis (NASH). We analyzed screening data from two phase 3 trials of selonsertib to assess the ability of NITs to discriminate advanced fibrosis. Centrally read biopsies from the STELLAR studies, which enrolled patients with bridging fibrosis and compensated cirrhosis, were staged according to the NASH Clinical Research Network classification. We explored associations between fibrosis stage and NITs, including the nonalcoholic fatty liver disease fibrosis score (NFS), fibrosis‐4 (FIB‐4) index, Enhanced Liver Fibrosis (ELF) test, and liver stiffness by vibration‐controlled transient elastography (LS by VCTE). The performance of these tests to discriminate advanced fibrosis, either alone or in combinations, was evaluated using areas under the receiver operating characteristic curve (AUROCs) with 5‐fold cross‐validation repeated 100 times. Of the 4,404 patients screened for these trials, 3,202 had evaluable biopsy data: 940 with F0‐F2 fibrosis and 2,262 with F3‐F4 fibrosis. Significant differences between median values of NITs for patients with F0‐F2 versus F3‐F4 fibrosis were observed: −0.972 versus 0.318 for NFS, 1.18 versus 2.20 for FIB‐4, 9.22 versus 10.39 for ELF, and 8.8 versus 16.5 kPa for LS by VCTE (all P < 0.001). AUROCs ranged from 0.75 to 0.80 to discriminate advanced fibrosis. FIB‐4 followed by an LS by VCTE or ELF test in those with indeterminate values (FIB‐4 between 1.3 and 2.67) maintained an acceptable performance while reducing the rate of indeterminate results. Conclusion: Among patients being considered for enrollment into clinical trials, NITs alone or in combination can reduce the need for liver biopsy to discriminate advanced fibrosis caused by NASH. The predictive value of these tests for general screening will require confirmation in a real‐world population.
Analyzing inappropriate magnetic resonance imaging (MRI) prescriptions and resulting economic burden on patients suffering from back pain
Authors: Jahanmehr Nader , Bigdeli Atieh Sadat , Salari Hedayat , Mokarami Hussein , KhodaKarim Soheila , Damiri Soheila 
Published: July 2019

SummaryIntroductionBack pain is a common global disorder and magnetic resonance imaging (MRI) is one method of assessing its cause. The lack of official and general clinical guidelines is the cause of inadequate supervision of lumbar MRI prescriptions. The goal of this research was to analyze inappropriate lumbar MRI prescriptions and the resulting economic burden on individuals.MethodThis is a descriptive‐analytical study carried out on a sample of 614 patients who visited four hospitals in Tehran. The appropriateness or inappropriateness of the MRI prescriptions was determined using clinical guidelines and a questionnaire based on previous studies. The economic burden created by inappropriate prescriptions for MRIs was determined after calculating the total direct and indirect costs.FindingsThe total MRI prescription cost paid by the study sample was $26 071, and the cost of inappropriate prescriptions was $10 310. The MRI prescription rate had a significant relationship with gender, age, education, employment, primary insurance type, and supplemental health insurance.ConclusionThe research findings revealed relatively high rates of inappropriate MRI prescriptions in the private and public sectors. Hence, policymakers should design, create, and develop clinical guidelines and enforce the policies and rules to decrease inappropriate MRI prescriptions.
Adverse events in Malaysia: Associations with nurse's ethnicity and experience, hospital size, accreditation, and teaching status
Authors: Jarrar Mu'taman , Al‐Bsheish Mohammad , Dardas Latefa Ali , Meri Ahmed , Sobri Minai Mohd 
Published: July 2019

SummaryPurposeIn Malaysia, private healthcare sector has become a major player in delivering healthcare services alongside the government healthcare sector. However, wide disparities in health outcomes have been recorded, and adverse events in these contexts have yet to be explored. The purpose of this study was to explore associations between nurse's ethnicity and experience, hospital size, accreditation, and teaching status with adverse events in Malaysian private hospitals.MethodsA cross‐sectional survey was conducted in 12 private hospitals in Malaysia. A total of 652 (response rate = 61.8%) nurses participated in the study. Data were collected using self‐administered questionnaire on nurses' characteristic, adverse events and events reporting, and perceived patient safety.ResultsPatient and family complaints events were the most common adverse events in Malaysian private hospitals as result of increased cost of care (3.24 ± 0.95) and verbal miscommunication (3.52 ± 0.87).ConclusionHospital size, accreditation status, teaching status, and nurse ethnicity had a mixed effect on patient safety, perceived adverse events, and events reporting. Policy makers can benefit that errors are related to several human and system related factors. Several system reforms and multidisciplinary efforts were recommended for optimizing health, healthcare and preventing patient harm.