bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ferroelectric Behavior of a Hexamethylenetetramine‐Based Molecular Perovskite Structure
Authors: Morita Hagino , Tsunashima Ryo , Nishihara Sadafumi , Inoue Katsuya , Omura Yuriko , Suzuki Yasutaka , Kawamata Jun , Hoshino Norihisa , Akutagawa Tomoyuki 
Published: May 2019

AbstractWe report the development of a molecular ferroelectric material inspired by the hexamethylenetetramine (hmta) non‐centrosymmetric molecular rotator. The bromide salt of diprotonated hmta (hmtaH2) crystalized as (hmtaH2)(NH4)Br3 in a metal‐free ABX3 perovskite‐type structure, in which the A and B sites are occupied by hmtaH22+ and ammonium cations, respectively. The compound crystallized in the Pma2 polar space group. A distorted polar perovskite structure formed owing to the distortion of {(NH4)Br6} octahedrons that are stabilized through the formation of NH⋅⋅⋅Br hydrogen bonds and the orientational ordering of positive charges on the non‐centrosymmetric hmtaH2 molecules. This spontaneous polarization exhibited ferroelectric behavior with a nominally high Curie temperature (>400 K), in which the electrical switching of polarization originates from the rotation of the hmtaH2 unit.
Unprecedented Regioregular Poly(1,4‐arylene)s Prepared by Nickel(II)‐Catalyzed Cross‐Coupling Polymerization of 2,5‐Disubstituted Bromo(chloro)arylene
Authors: Shibuya Yushin , Nakagawa Naoki , Miyagawa Naoki , Suzuki Toyoko , Okano Kentaro , Mori Atsunori 
Published: May 2019

AbstractThe unprecedented synthesis of regioregular head‐to‐tail‐type poly(1,4‐arylene)s bearing different substituents at the 2‐ and 5‐positions is described. They were prepared by the polymerization of 2,5‐disubstituted bromo(chloro)arylenes by selective halogen–metal exchange with a Grignard reagent and subsequent cross‐coupling polymerization with a nickel catalyst [NiCl2(dppp)]. Formation of the regioregular poly(1,4‐arylene)s were confirmed by NMR spectroscopy, and showed remarkable differences to those polymers having uncontrolled regioregularity. Polymerization of bromo(chloro)arylenes with a chiral alkoxy substituent also led to the regioregular head‐to‐tail‐type polyarylene, which demonstrated circular dichroism, thus suggesting formation of a structure with higher‐order regularity.
Preparation and characterization of melt‐stretched polypropylene–polypropylene‐g‐poly(α‐methyl styrene‐co‐glycidyl methacrylate‐co‐γ‐methacryloxypropyl trimethoxy silane)–silicon dioxide compound microporous membranes
Authors: Jiang Shan , Wang Wei , Chen Wei , Zhang Hongwen , Wang Kemin 
Published: May 2019

ABSTRACTPolypropylene (PP)–silicon dioxide (SiO2) compound microporous membranes were fabricated by a melt‐stretching method. Although the permeability, porosity, and hydrophilicity values of the microporous membranes were found to be highest at an SiO2content of 2 wt %, the heat resistance of the membranes was relatively low. To improve the heat resistance of the microporous membranes, a macromolecular coupling agent, PP‐g‐poly(α‐methyl styrene‐co‐glycidyl methacrylate‐co‐γ‐methacryloxypropyl trimethoxy silane) (PAGK), was introduced into the membrane. In the PP–PP‐g‐PAGK–SiO2composite systems, the content of SiO2was controlled at 2 wt %, and the proportion of PP‐g‐PAGK was varied. With increasing PP‐g‐PAGK content to 0.6%, the Gurley value decreased from 250 to 239 s, and the porosity increased from 50.8 to 51.6%. The hydrophilicity of the microporous membranes increased with the incorporation of PP‐g‐PAGK, and their water vapor transmission rate reached a maximum of 3360 g m−2/24 h at a PP‐g‐PAGK content of 0.6%. The heat resistance of the PP–PP‐g‐PAGK–SiO2compound microporous membranes was slightly higher than that of the pure PP microporous membrane. Additionally, the cycle performance of a cell assembled with the PP–PP‐g‐PAGK–SiO2membrane was better than that constructed with the pure PP membrane. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47937.
A new protocol for psychrometric pressure–volume curves of fern gametophytes
Authors: Krieg Christopher P. , Watkins James E. , McCulloh Katherine A. 
Published: May 2019

PremisePressure–volume curves are a widely used analytical framework to derive several key physiological traits related to plant–water relations, including a species’ turgor loss point, osmotic potential at full turgor, and the elasticity of cell walls. We developed a novel protocol, including the preparation and treatment of fern gametophytes, to generate data for pressure–volume curve analyses using thermocouple psychrometry.Methods and ResultsGametophytes of the fern species Polystichum lemmonii were grown from spore, harvested, and subjected to a series of drying intervals. We constructed pressure–volume curves using thermocouple psychrometers to calculate gametophyte water potential and a balance to measure relative water loss.ConclusionsWe present the first protocol for fern gametophyte pressure–volume curves that can accurately determine key physiological traits in fern gametophytes such as the turgor loss point and osmotic potential at full turgor.
Investigation of binding between fluoroquinolones and pepsin by fluorescence spectroscopy and molecular simulation
Authors: Lian Shu‐Qin , Lian Jie , Wang Gui‐Rong , Li Lin , Yang Dong‐Zhi , Xue Yun‐sheng 
Published: May 2019

AbstractIn this paper, the interactions of pepsin with fluoroquinolones, including norfloxacin (NFX) or ofloxacin (OFX), were investigated using fluorescence spectroscopy. The effects of NFX or OFX on pepsin showed that the molecular conformation of pepsin and the microenvironment of tryptophan residues were changed under mimicked physiological conditions. Static quenching was suggested as a factor. Quenching constants and binding constants were determined and thermodynamic parameters were calculated at three temperatures (25°C, 31°C and 37°C). Molecular interaction distances (binding distance r) were obtained. Binding was enthalpy driven and the process was spontaneous. Synchronous fluorescence, three‐dimensional fluorescence spectroscopy and molecular simulation were used for analysis. Interactions were further tested using molecular modelling. Quenching and binding constants of NFX with pepsin were the highest when testing NFX/OFX/fleroxacin/gatifloxacin with pepsin combinations. NFX was the strongest quencher, and affinity of NFX for pepsin was higher than that of OFX/fleroxacin/gatifloxacin.
Isomorphic or dissimilar implementation among environmental management scheme adopters? Empirical evidence from the European context
Authors: Tessitore Sara , Testa Francesco , Iraldo Fabio , Daddi Tiberio 
Published: May 2019

AbstractThe research assessed the extent to which an environmental management scheme (EMS) had been implemented in 242 Environmental Management and Audit Scheme (EMAS)‐registered companies in Europe. The actions taken by the surveyed enterprises to comply with the EMAS Regulation (1221/2009) and to implement the Deming cycle that characterizes the environmental management system and the EMAS standard were analyzed. We exploited a new institutional theory, which suggests that a firm's operations exert ongoing pressure on its decisions, leading to isomorphic behavior. The survey results were processed using cluster analysis, thereby enabling us to classify the companies into four groups. The classification of the groups is based on the implementation of Deming cycle composed of four main steps (“plan‐do‐check‐act”). These steps were totally or partially adopted by the EMAS companies.So, different level of EMAS implementation emerged from the research. The cluster analysis confirmed that EMSs can be implemented in different ways and that EMAS achievements can be discretionary. If the scheme is not integrated into the organization, then a firm's adoption of EMS is likely to be only symbolic.
ARduino‐pH Tracker and screening platform for characterization of recombinant carbonic anhydrase in Escherichia coli
Authors: Hsu Kao‐Pang , Tan Shih‐I , Chiu Chen‐Yaw , Chang Yu‐Kaung , Ng I‐Son 
Published: May 2019

AbstractCarbonic anhydrase (CA, EC 4.2.1.1) is an ancient enzyme with zinc ion as its active site, which catalyzes the chemical reaction of carbon dioxide (CO2) to react with water and form bicarbonate ions. Due to its high catalytic efficiency on CO2 assimilation, CA is expected to use for carbon sequestration in industry. However, the protein expression level, thermostability and high‐throughput screening of an active CA are still with difficulty. In this study, the CA from Sulfurihydrogenibium yellowstonense (denoted as SyCA) was selected for overexpressed in Escherichia coli by different pET vectors. The enzymatic properties including thermo‐stability, pH tolerance, effect of metal ion, and kinetic parameters were characterized through a novel ARduino‐pH Tracker (ART) for monitoring online effectively. The SyCA is thermophilic and acidophilic as it maintains 100% activity at 50°C, while the residual activity is 34.8% after heating at 80°C for 150 min and the optimal pH is 3–5. The kinetic analysis by ART system showed that the k
cat/K
m of free enzyme was 4.4‐folds that that of whole cell. On the other hand, the screening platforms as Wilbur–Anderson unit, phenol red indicator and size of colony forming unit have been established to explore CA with higher activity. The high‐throughput screening platform is support in direct evolution of CA and further used in the industry.
Impact of the preoperative prognostic nutritional index on survival outcomes in upper tract urothelial carcinomas
Authors: Xue Wenbin , Tan Ping , Xu Hang , Yang Lu , Wei Qiang 
Published: May 2019

AbstractPurposesTo investigate the value of prognostic nutritional index (PNI) in patients with upper tract urothelial carcinoma (UTUC) who underwent radical nephroureterectomy (RNU).Patients and methodsA total of 717 patients were included in our study from 2003 to 2016. PNI was calculated as 10 × serum albumin level (g/dL) + 0.005 × total lymphocyte count (per mm3). Kaplan‐Meier analysis and Cox regression models were adapted to analyze the value of PNI on survival outcomes.ResultsThe cutoff value of PNI was set as 46.91 and 298 patients (47.6%) had PNI <46.91. The median follow‐up was 50 months. The results suggested that low PNI was significantly associated with worse pathologic features (all P < 0.001). Multivariable Cox regression analysis revealed that PNI < 46.91 was an independent predictor of poor overall survival (Hazard ratios [HR] = 1.777, 95% CI = 1.383‐2.284, P < 0.001), cancer‐specific survival (HR = 1.850, 95% CI = 1.399‐2.445, P < 0.001), and recurrence‐free survival (HR = 1.554, 95% CI = 1.229‐1.964, P < 0.001).ConclusionsLow preoperative PNI was associated with worse survival outcomes in patients with UTUC. PNI could be an easily assessed blood‐based biomarker to predict the prognosis in patients with UTUC treated with RNU.
Consequences of a high incidence of microsatellite instability and BRAF‐mutated tumors: A population‐based cohort of metastatic colorectal cancer patients
Authors: Aasebø Kristine Ø. , Dragomir Anca , Sundström Magnus , Mezheyeuski Artur , Edqvist Per‐Henrik , Eide Geir Egil , Ponten Fredrik , Pfeiffer Per , Glimelius Bengt , Sorbye Halfdan 
Published: May 2019

AbstractBackgroundImmunotherapy for patients with microsatellite‐instable (MSI‐H) tumors or BRAF‐inhibitors combination treatment for BRAF‐mutated (mutBRAF) tumors in metastatic colorectal cancer (mCRC) is promising, but the frequency of these molecular changes in trial patients are low. Unselected population‐based studies of these molecular changes are warranted.MethodsA population‐based cohort of 798 mCRC patients in Scandinavia was studied. Patient and molecular tumor characteristics, overall survival (OS) and progression‐free survival (PFS) were estimated.ResultsHere, 40/583 (7%) tumor samples were MSI‐H and 120/591 (20%) were mutBRAF; 87% of MSI‐H tumors were mutBRAF (non‐Lynch). Elderly (>75 years) had more often MSI‐H (10% vs 6%) and MSI‐H/mutBRAF (9% vs 4%) tumors. Response rate (5% vs 44%), PFS (4 vs 8 months), and OS (9 vs 18 months) after first‐line chemotherapy was all significantly lower in patients with MSI‐H compared to patients with microsatellite stable tumors. MSI‐H and mutBRAF were both independent poor prognostic predictors for OS (P = 0.049, P < 0.001) and PFS (P = 0.045, P = 0.005) after first‐line chemotherapy. Patients with MSI‐H tumors received less second‐line chemotherapy (15% vs 37%, P = 0.005).ConclusionsIn unselected mCRC patients, MSI‐H and mutBRAF cases were more common than previously reported. Patients with MSI‐H tumors had worse survival, less benefit from chemotherapy, and they differed considerably from recent third‐line immunotherapy trial patients as they were older and most had mutBRAF tumor (non‐Lynch).
Deciphering the Crystal Structure of a Scarce 1D Polymeric Thorium Peroxo Sulfate
Authors: Bonato Laura , Virot Matthieu , Dumas Thomas , Mesbah Adel , Lecante Pierre , Prieur Damien , Le Goff Xavier , Hennig Christoph , Dacheux Nicolas , Moisy Philippe , Nikitenko Sergey I. 
Published: May 2019

AbstractThe preparation and structural characterization of an original Th peroxo sulfate dihydrate, crystallizing at room temperature in the form of stable 1D polymeric microfibres is described. A combination of laboratory and synchrotron techniques allowed solution of the structure of the Th(O2)(SO4)(H2O)2 compound, which crystallizes in a new structure type in the space group Pna21 of the orthorhombic crystal system. Particularly, the peroxide ligand coordinates to the Th cations in an unusual μ3‐η2:η2:η2 bridging mode, forming an infinite 1D chain decorated with sulfato ligands exhibiting simultaneously monodentate and bidentate coordination modes.
Triple Helical Ir(ppy)3 Phenylene Cage Prepared by Diol‐Mediated Benzannulation: Synthesis, Resolution, Absolute Stereochemistry and Photophysical Properties
Authors: Sato Hiroki , Blemker Michelle A. , Hellinghausen Garrett , Armstrong Daniel W. , Nafie Jordan W. , Roberts Sean T. , Krische Michael J. 
Published: May 2019

AbstractCyclometalation of a triple helical N‐doped phenylene cage prepared by ruthenium(0)‐catalyzed diol–diene benzannulation delivers a chiral, conformationally constrained Ir(ppy)3 analogue. Like the parent complex, fac‐Ir(ppy)3, the iridium‐containing PAH‐cage is phosphorescent, but displays enhanced resistance to oxygen quenching.
Family Firm Heterogeneity and Tax Aggressiveness: A Mixed Gamble Approach
Authors: Bauweraerts Jonathan , Vandernoot Julien , Buchet Antoine 
Published: May 2019

AbstractFew studies try to understand how the unique preferences of family firms affect tax strategies, and how family firm heterogeneity drives variation in tax activities. Drawing on the mixed gamble approach, this study examines the tax aggressiveness of different types of family firms, considering how various sources of heterogeneity alter the perception of potential gains and losses to socioemotional and financial wealth. Based on a panel dataset of 242 private family firms for the period 2012–2014, this study shows that strong family‐owned firms, family firms with a family CFO, family‐founder firms, and family‐named firms display lower levels of tax aggressiveness. These findings demonstrate that family firm heterogeneity is a crucial factor in the mixed gamble calculus of tax aggressiveness.
Combined substrate micropatterning and FFT analysis reveals myotube size control and alignment by contact guidance
Authors: Vajanthri Kiran Yellappa , Sidu Rakesh Kumar , Poddar Suruchi , Singh Ashish Kumar , Mahto Sanjeev Kumar 
Published: May 2019

AbstractMost important evaluating criteria for in vitro skeletal muscle models include the extent of differentiation and the degree of alignment in the tissue model. Substrate micropatterning is considered as an effective tool as it recreates in vivo like cellular microenvironment and helps in understanding the fundamental concepts and mechanisms underlying myogenesis. However, the influence of micropatterning based contact guidance cues over satellite cell alignment and myotube formation needs to be explored and studied further. In the present work, we demonstrate the regulation of myotube size control and alignment through the substrate micropatterning. For this purpose, primary myoblast cells (i.e., satellite cells) isolated from rat hind limb muscle were characterized and cultured for a period of 14 days on micropatterned glass substrates processed by the microchannnel flowed plasma process. Several characteristic parameters of muscle differentiation, including the fusion index, maturation index, and average width of the myotubes were quantified. The functional behavior of cultured myotubes exhibiting spontaneous contractions was assessed through kymograph to determine the twitch frequency. In addition, we evaluated the degree of alignment of myotubes on micropatterned substrates through examining orientation order parameter and two‐dimensional fast Fourier transform analysis. Altogether, the outcomes reveal that the contact guidance cues arising due to micropatterning of the substrates could be a key regulator for controlling the size and degree of alignment of myotubes during the myogenesis process.
Runtime deadlock tracking and prevention of concurrent multithreaded programs: A learning‐based approach
Authors: Ghorbani Mehrdad , Babamir Seyed Morteza 
Published: May 2019

SummaryAllocation of shared resources by multithreaded programs faces problem of deadlock. Many solutions have been presented to resolve this problem. Among others, the deadlock prevention is stressed when the deadlock detection and removal are costly. Removing deadlocks, which is carried out by aborting/recovering deadlocked threads, causes the waste of the resources used by the deadlocked threads. In such case, deadlock prevention can lead to avoiding the waste of resources. To this end, the runtime behavior of threads should be monitored in order to predict possible future deadlocks. In such case, the prediction mechanism becomes significant because a proper prediction helps us deny the allocation request of a resource by a thread if the allocation leads to a potential deadlock. A method to attain to proper prediction is learning the behavior of threads based on runtime monitoring their past behavior. In fact, based on past behavior of threads, potential deadlocks in their future behavior are verified, and current allocation request of a resource is denied if a future deadlock is predicted. The current study is an extension of our previous work where just deadlock tracking was predicted and no adaptation was suggested. In this study, a composite structure of a recurrent Neural Network (NN) called NARX (to track a potential deadlock) and a Multi‐perceptron NN called MLP (to select a suitable action to resolve the potential deadlock) is proposed. Based on the experimental results, the accuracy of the first NN was about 80%, leading to high performance of the second NN, and more than 82% of the real deadlocks were prevented by selecting suitable actions.
The Influence of Calcium Traces in Ultrapure Water on the Lateral Organization in Tetramyristoyl Cardiolipin Monolayers
Authors: Sturm Marina , Gutowski Olof , Brezesinski Gerald 
Published: May 2019

AbstractCardiolipin (CL) plays an important role in administering the structural organization of biological membranes and therefore helps maintaining the integer membrane functionality. CL has a dimeric structure consisting of four acyl chains and two phosphate groups. With its unusual structure, the phospholipid is responsible for curvature formation in CL containing biological membranes. The acidic properties of the phosphate head groups are still not sufficiently investigated since there are controversial results in literature. The main aim of this work was to gain deeper insights into the influence of the pH on the ionization degree of CL. During the experiments, it became clear that the used ultrapure water contained traces of calcium. These unexpected calcium ions had a major impact on the behavior of CL monolayers. Therefore, the focus was put on the analysis of CL layers without and with EDTA in the subphase used to complex divalent calcium ions. For the analyses, traditional surface pressure (π) – molecular area (A) isotherm experiments combined with total reflection x‐ray fluorescence (TRXF) and grazing incidence x‐ray diffraction (GIXD) have been used.
SAPO‐34 Framework Contraction on Adsorption of Ammonia: A Neutron Scattering Study
Authors: Silverwood Ian P. 
Published: May 2019

AbstractNeutron scattering data was recorded from SAPO‐34 using the OSIRIS instrument before and after repeated ammonia adsorption at pressures up to 8 bar. Coherent scattering from the zeolite framework provides the neutron powder diffraction pattern and gave evidence for anisotropic contraction on ammonia dosing. Incoherent quasielastic scattering from the hydrogen of the ammonia showed that mobile ammonia was present in the framework. The quasielastic data was fitted to a model where the ammonia was confined within the chabazite cage in the c direction of the crystal lattice, with diffusion solely occurring through the perpendicular 8‐membered rings. The calculated diffusion constant reached a maximum of 6.3×10−8 m2 s−1 at 5 bar.
Toward Luminescent Iron Complexes: Unravelling the Photophysics by Computing Potential Energy Surfaces
Authors: Francés‐Monerris Antonio , Gros Philippe C. , Assfeld Xavier , Monari Antonio , Pastore Mariachiara 
Published: May 2019

AbstractDue to its high societal impact, the replacement of precious metals used in technological devices by more abundant and eco‐friendly metals, such as iron, has stimulated significant scientific efforts in the last years. In the present review, we focus on different computational strategies and techniques used to characterize the potential energy surfaces (PESs) that govern the photophysical pathways of a wide variety of FeII complexes. The different procedures are discussed in terms of accuracy, computational cost and availability of the implementations, and illustrated with specific examples taken from the literature. The determination of minimum energy paths (MEPs) and the optimization of minimum energy crossing points (MECPs) are particularly emphasized since they can be combined to provide connected and optimized PESs independent from any a priori selected coordinate. The use of such computational techniques is exemplified in detail through a recent study on the influence of the facial and meridional isomerism in the triplet PESs of a pyridylcarbene Fe(II) complex, and its implications in the decay mechanism of each isomer.
WRE‐OLSR, a new scheme for enhancing the lifetime within ad hoc and wireless sensor networks
Authors: Belkhira Sid Ahmed Hichame , Boukli Hacene Sofiane , Lorenz Pascal , Belkheir Mohammed , Gilg Marc , Bouziani Merahi 
Published: May 2019

SummaryWithin ad hoc and wireless sensor networks, communications are accomplished in dynamic environments with a random movement of mobile devices. Thus, routing protocols over these networks are an important concern to offer efficient network scalability, manage topology information, and prolong the network lifetime. Optimized link state routing (OLSR) is one of those routing protocols implemented in ad hoc and wireless sensor networks. Because of its proactive technique, routes between two nodes are established in a very short time, but it can spend a lot of resources for selecting the multipoint relays (MPRs: nodes responsible for routing data) and exchanging topology control information. Thus, nodes playing for a long time a role of MPR within networks implementing such protocol can rapidly exhaust their batteries, which create route failures and affect the network lifetime. Our main approach relies on analyzing this concern by introducing a new criterion that implements a combination between the residual energy of a node and its reachability in order to determine the optimal number of MPRs and sustain the network lifetime. Simulations performed illustrate obviously that our approach is more significant compared with the basic heuristic used by original OLSR to compute the MPR set of a node.