bluuebunny/crossref_metadata_2025_split huggingface dataset:
Superconducting Phases of Phosphorus Hydride Under Pressure: Stabilization by Mobile Molecular Hydrogen
Authors: Bi Tiange , Miller Daniel P. , Shamp Andrew , Zurek Eva 
Published: May 2017

AbstractAt 80 GPa, phases with the PH2 stoichiometry, which are composed of simple cubic like phosphorus layers capped with hydrogen atoms and layers of H2 molecules, are predicted to be important species contributing to the recently observed superconductivity in compressed phosphine. The electron–phonon coupling in these phases results from the motions of the phosphorus atoms and the hydrogen atoms bound to them. The role of the mobile H2 layers is to decrease the Coulomb repulsion between the negatively charged hydrogen atoms capping the phosphorus layers. An insulating PH5 phase, the structure and bonding of which is reminiscent of diborane, is also predicted to be metastable at this pressure.
Entropy Drives the Formation of Salt Bridges in the Protein GB3
Authors: Zhang Ning , Wang Yefei , An Liaoyuan , Song Xiangfei , Huang Qingshan , Liu Zhijun , Yao Lishan 
Published: May 2017

AbstractSalt bridges are very common in proteins. But what drives the formation of protein salt bridges is not clear. In this work, we determined the strength of four salt bridges in the protein GB3 by measuring the ΔpKa values of the basic residues that constitute the salt bridges with a highly accurate NMR titration method at different temperatures. The results show that the ΔpKa values increase with temperature, thus indicating that the salt bridges are stronger at higher temperatures. Fitting of ΔpKa values to the van't Hoff equation yields positive ΔH and ΔS values, thus indicating that entropy drives salt‐bridge formation. Molecular dynamics simulations show that the protein and solvent make opposite contributions to ΔH and ΔS. Specifically, the enthalpic gain contributed from the protein is more than offset by the enthalpic loss contributed from the solvent, whereas the entropic gain originates from the desolvation effect.
AgPt nanoparticles supported on magnetic graphene oxide nanosheets for catalytic reduction of 4‐nitrophenol: Studies of kinetics and mechanism
Authors: Kohantorabi Mona , Gholami Mohammad Reza 
Published: May 2017

AgxPt100−x (x = 0, 25, 50, 75 and 100) nanoparticles were grown on the surface of magnetic graphene oxide nanosheets (Fe3O4@GO) for the first time. The as‐prepared nanocomposites were characterized using various techniques such as Fourier transform infrared spectroscopy, powder X‐ray diffraction, field emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area analysis, vibrating sample magnetometry and thermogravimetric analysis. The Fe3O4@GO‐AgxPt100−x catalysts were applied in the reduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol using sodium borohydride (NaBH4). The synthesized nanocomposites exhibited excellent catalytic performance in the reduction of 4‐NP with high recyclability for five consecutive runs. The Fe3O4@GO‐Ag75Pt25 nanocomposite exhibited the best catalytic activity with a rate constant as high as 140.6 × 10−3 s−1. The obtained kinetic data were modelled with the Langmuir–Hinshelwood equation. The energy of activation and thermodynamic parameters including enthalpy, entropy of activation and activation Gibbs free energy were calculated.
Mononuclear metal (II) complexes of a Bis(organoamido)phosphate ligand with antimicrobial activities against Escherichia coli
Authors: Pal Souvik , Tarafdar Abhrajyoti , Sinha Alok , Bhunia Asamanjoy , Harms Klaus , Nayek Hari Pada 
Published: May 2017

A new tripodal ligand [PO(NH2MePy)3] (L) (2MePy = 2‐(4‐methyl pyridyl)) have been synthesized by treating phosphorous oxychloride with 2‐Amino‐4‐methylpyridine in toluene under refluxing condition. The ligand was appeared as a white solid and characterized by several standard analytical and spectroscopic techniques such as FT‐IR, NMR (1H, 13C{1H} and 31P{1H}) and ESI‐MS spectroscopy. The ligand (L) undergone metal‐assisted hydrolysis of one P–N bond when treated it with hydrated metal nitrates, M(NO3)2·xH2O (M = Zn, Cu, Co and Ni) under hydrothermal reaction condition in DMF‐H2O (1:1). This results in the formation of four mononuclear complexes [{PO2(NH2MePy)2}2M] [M = Zn (1), Cu (2), Co (3), Ni (4)], where ligand (L) hydrolyses to a anionic bis(organoamido)phosphate, [PO2(NH2MePy)2]−. All complexes were completely characterized by various analytical techniques and their solid state molecular structures were established by single crystal X‐ray diffraction. All complexes are isostructural with a metal (II) ion situating at the centre of a distorted octahedron. Two tridentate [PO2(NH2MePy)2]− ligands are coordinated to metal(II) ion through N‐ and O‐donor atoms, thus neutralizing the charge of the complex. Optical properties of all complexes in solid state have been studied. Moreover, antimicrobial activities of complexes 1–4 have been explored. To the best of our knowledge, this is the first report of such compounds investigated for their antimicrobial activities.
Synthesis of polystyrene latex via emulsion polymerization with poly(vinyl alcohol) as sole stabilizer
Authors: Lu Yangcheng , Liu Xiaojing , Luo Guangsheng 
Published: May 2017

ABSTRACTCompared with low molecular surfactants, poly(vinyl alcohol) (PVA) could afford latexes with particular tackiness as an important property for various applications. However, until now, except for some highly reactive monomers, most of monomers including styrene seldom use PVA as protective colloid in emulsion polymerization. In this work, we used oil‐soluble initiator, 2,2′‐azobisisobutyronitrile, to accelerate the copolymerization of styrene and divinyl benzene in PVA protected colloids and synthesize polystyrene (PS) latex within 50 min at 70 °C successfully. The reaction system could remain stable even at the monomer‐to‐water ratio as high as 1:4, and the polymerization in pseudo‐micelles or latex particles was always dominant. The adjustment of the size of the PS latex in the range from 70 to 100 nm was facilely achieved by changing the polymerization temperature, the addition of PVA, or the monomer‐to‐water ratio. This method was also exploited to synthesize poly(styrene‐co‐methyl methacrylate) and poly(styrene‐co‐4‐chlorostyrene) latexes, indicating prospects in applications with the advantages of high capacity and broad applicability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45111.
Numerical and experimental investigations on polymer melt flow phenomenon in a vario‐thermal mold cavity
Authors: Liu Jitao , Zhang Shuxiang , Zhao Guoqun , Wang Guilong 
Published: May 2017

ABSTRACTMold temperature is one of the key factors affecting the morphology and quality of plastic parts. This article explores the melt flow phenomena in a vario‐thermal mold cavity. A coupled numerical method, considering the conjugate heat transfer between the mold and melt, is developed for the melt flow simulation. Mold temperature variations and melt flow phenomena for short shot injection in an electrical heated mold cavity are numerically studied and verified by experiments. The results indicate that the melt flow length and cavity filling ratio increase significantly with the elongation of the preheating time before injection. Melt filling ratio increased nearly linearly with the increasing of electric heating time. The smaller the injection pressure is, the bigger the relative filling ratio increment is. Therefore, polymer melt can flow much longer or the mold cavity can be filled up with a smaller injection pressure when the cavity is preheated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45193.
Short DNA containing χ sites enhances DNA stability and gene expression in E. coli cell‐free transcription–translation systems
Authors: Marshall Ryan , Maxwell Colin S. , Collins Scott P. , Beisel Chase L. , Noireaux Vincent 
Published: May 2017

ABSTRACTEscherichia coli cell‐free transcription–translation (TXTL) systems offer versatile platforms for advanced biomanufacturing and for prototyping synthetic biological parts and devices. Production and testing could be accelerated with the use of linear DNA, which can be rapidly and cheaply synthesized. However, linear DNA is efficiently degraded in TXTL preparations from E. coli. Here, we show that double‐stranded DNA encoding χ sites—eight base‐pair sequences preferentially bound by the RecBCD recombination machinery—stabilizes linear DNA and greatly enhances the TXTL‐based expression and activity of a fluorescent reporter gene, simple regulatory cascades, and T7 bacteriophage particles. The χ‐site DNA and the DNA‐binding λ protein Gam yielded similar enhancements, and DNA with as few as four χ sites was sufficient to ensure robust gene expression in TXTL. Given the affordability and scalability of producing the short χ‐site DNA, this generalized strategy is expected to advance the broad use of TXTL systems across its many applications. Biotechnol. Bioeng. 2017;114: 2137–2141. © 2017 Wiley Periodicals, Inc.
A simple and sensitive high‐performance liquid chromatography–electrochemical detection assay for the quantitative determination of monoamines and respective metabolites in six discrete brain regions of mice
Authors: Allen Serena A. , Rednour Stephanie , Shepard Samantha , Pond Brooks Barnes 
Published: May 2017

AbstractA rapid, sensitive, and reproducible assay is described for the quantitative determination of the monoamine neurotransmitters dopamine, norepinephrine and serotonin, their metabolites, and the internal standard 3,4‐dihydroxybenzlyamine hydro‐bromide in mouse brain homogenate using high‐performance liquid chromatography with electrochemical detection. The method was validated in the following brain areas: frontal cortex, striatum, nucleus accumbens, hippocampus, substantia nigra pars compacta and ventral tegmental area. Biogenic amines and relevant metabolites were extracted from discrete brain regions using a simple protein precipitation procedure, and the chromatography was achieved using a C18 column. The method was accurate over the linear range of 0.300–30 ng/mL (r = 0.999) for dopamine and 0.300–15 ng/mL (r = 0.999) for norepinephrine, 3,4‐dihydroxybenzlyamine hydro‐bromide, homovanillic acid and 5‐hydroxyindolacetic acid, with detection limits of ~0.125 ng/mL (5 pg on column) for each of these analytes. Accuracy and linearity for serotonin were observed throughout the concentration range of 0.625–30 ng/mL (r = 0.998) with an analytical detection limit of ~0.300 ng/mL (12 pg on column). Relative recoveries for all analytes were approximately ≥90% and the analytical run time was <10 min. The described method utilized minimal sample preparation procedures and was optimized to provide the sensitivity limits required for simultaneous monoamine and metabolite analysis in small, discrete brain tissue samples.
Biomarkers expression in benign breast diseases and risk of subsequent breast cancer: a case–control study
Authors: Posso Margarita , Corominas Josep M. , Serrano Laia , Román Marta , Torá‐Rocamora Isabel , Domingo Laia , Romero Anabel , Quintana María Jesús , Vernet‐Tomas María , Baré Marisa , Vidal Carmen , Sánchez Mar , Saladié Francina , Natal Carmen , Ferrer Joana , Servitja Sònia , Sala María , Castells Xavier ,   the BELE Study Group
Published: May 2017

AbstractWomen with benign breast diseases (BBD) have a high risk of breast cancer. However, no biomarkers have been clearly established to predict cancer in these women. Our aim was to explore whether estrogen receptor (ER), progesterone receptor (PR), and Ki67 expression stratify risk of breast cancer in screened women with BBD. We conducted a nested case–control study. Women with breast cancer and prior BBDs (86 cases) were matched to women with prior BBDs who were free from breast cancer (172 controls). The matching factors were age at BBD diagnosis, type of BBD, and follow‐up time since BBD diagnosis. ER, PR, and Ki67 expression were obtained from BBDs’ specimens. Conditional logistic regression was used to estimate odds ratios (ORs), and 95% confidence intervals (CIs) of breast cancer risk according to ER, PR, and Ki67 expression. Women with >90% of ER expression had a higher risk of breast cancer (OR = 2.63; 95% CI: 1.26–5.51) than women with ≤70% of ER expression. Similarly, women with >80% of PR expression had a higher risk of breast cancer (OR = 2.22; 95% CI: 1.15–4.27) than women with ≤40% of PR expression. Women with proliferative disease and ≥1% of Ki67 expression had a nonsignificantly increased risk of breast cancer (OR = 1.16; 95% CI: 0.46–2.90) than women with <1% of Ki67 expression. A high expression of ER and PR in BBD is associated with an increased risk of subsequent breast cancer. In proliferative disease, high Ki67 expression may also have an increased risk. This information is helpful to better characterize BBD and is one more step toward personalizing the clinical management of these women.
Three in One: Temperature, Solvent and Catalytic Stability by Engineering the Cofactor‐Binding Element of Amine Transaminase
Authors: Börner Tim , Rämisch Sebastian , Bartsch Sebastian , Vogel Andreas , Adlercreutz Patrick , Grey Carl 
Published: May 2017

AbstractAmine transaminase (ATA) catalyse enantioselectively the direct amination of ketones, but insufficient stability during catalysis limits their industrial applicability. Recently, we revealed that ATAs suffer from substrate‐induced inactivation mechanism involving dissociation of the enzyme–cofactor intermediate. Here, we report on engineering the cofactor‐ring‐binding element, which also shapes the active‐site entrance. Only two point mutations in this motif improved temperature and catalytic stability in both biphasic media and organic solvent. Thermodynamic analysis revealed a higher melting point for the enzyme–cofactor intermediate. The high cofactor affinity eliminates the need for pyridoxal 5′‐phosphate supply, thus making large‐scale reactions more cost effective. This is the first report on stabilising a tetrameric ATA by mutating a single structural element. As this structural “hotspot” is a common feature of other transaminases it could serve as a general engineering target.
Access to the native atria following conduit total cavopulmonary anastomosis
Authors: Petersen Robert L. , Danon Saar , Jureidini Saadeh 
Published: May 2017

ObjectivesWe describe the use of trans‐thoracic and trans‐conduit puncture to access the atria and perform interventional procedures in patients who have undergone conduit total cavopulmonary anastomosis.BackgroundCatheter access to the atria following intra or extra‐cardiac Fontan is desirable when there is a need for trans‐atrial interventions.MethodsBetween 2009 and 2014, 5 patients ages 7 to 28 years underwent this approach; three trans‐thoracic and 2 trans‐conduit punctures. Various therapeutic aims were achieved. Included are: placement of pacing wire in the left atrial appendage, access to re‐canalized left superior vena cava via the coronary sinus for device occlusion eliminating cyanosis, access with subsequent device closure of a dormant pulmonary valve thought to be the nidus of an embolic event, and access to the atria for ablation of an atrial tachycardia.ResultsEntry to the atria was successful in all five patients with either trans‐thoracic access or trans‐conduit puncture with subsequent intended intervention performed successfully.ConclusionsTrans‐conduit puncture and trans‐thoracic access may allow therapeutic procedures which mitigate the need for further open heart surgery. © 2017 Wiley Periodicals, Inc.
Towards a contemporary, comprehensive scoring system for determining technical outcomes of hybrid percutaneous chronic total occlusion treatment: The RECHARGE score
Authors: Maeremans Joren , Spratt James C. , Knaapen Paul , Walsh Simon , Agostoni Pierfrancesco , Wilson William , Avran Alexandre , Faurie Benjamin , Bressollette Erwan , Kayaert Peter , Bagnall Alan J. , Smith Dave , McEntegart Margaret B. , Smith William H.T. , Kelly Paul , Irving John , Smith Elliot J. , Strange Julian W. , Dens Jo 
Published: May 2017

ObjectivesThis study sought to create a contemporary scoring tool to predict technical outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) from patients treated by hybrid operators with differing experience levels.BackgroundCurrent scoring systems need regular updating to cope with the positive evolutions regarding materials, techniques, and outcomes, while at the same time being applicable for a broad range of operators.MethodsClinical and angiographic characteristics from 880 CTO‐PCIs included in the REgistry of CrossBoss and Hybrid procedures in FrAnce, the NetheRlands, BelGium and UnitEd Kingdom (RECHARGE) were analyzed by using a derivation and validation set (2:1 ratio). Variables significantly associated with technical failure in the multivariable analysis were incorporated in the score. Subsequently, the discriminatory capacity was assessed and the validation set was used to compare with the J‐CTO score and PROGRESS scores.ResultsTechnical success in the derivation and validation sets was 83% and 85%, respectively. Multivariate analysis identified six parameters associated with technical failure: blunt stump (beta coefficient (b) = 1.014); calcification (b = 0.908); tortuosity ≥45° (b = 0.964); lesion length 20 mm (b = 0.556); diseased distal landing zone (b = 0.794), and previous bypass graft on CTO vessel (b = 0.833). Score variables remained significant after bootstrapping. The RECHARGE score showed better discriminatory capacity in both sets (area‐under‐the‐curve (AUC) = 0.783 and 0.711), compared to the J‐CTO (AUC = 0.676) and PROGRESS (AUC = 0.608) scores.ConclusionsThe RECHARGE score is a novel, easy‐to‐use tool for assessing the risk for technical failure in hybrid CTO‐PCI and has the potential to perform well for a broad community of operators. © 2017 Wiley Periodicals, Inc.
Twenty years of experience with intraoperative pulmonary artery stenting
Authors: Zampi Jeffrey D. , Loccoh Emefah , Armstrong Aimee K. , Yu Sunkyung , Lowery Ray , Rocchini Albert P. , Hirsch‐Romano Jennifer C. 
Published: May 2017

ObjectivesTo describe our 20‐year experience with intraoperative pulmonary artery (PA) stent placement and evaluate long‐term patient outcomes, specifically the need and risk factors for reintervention.BackgroundIntraoperative PA stent placement is an alternative to surgical patch arterioplasty and percutaneous angioplasty or stent placement to treat branch PA stenosis.MethodsWe performed a retrospective review of all intraoperative PA stents placed at our institution from 1994‐2013. Patient and stent characteristics and outcome data were collected. Risk factors associated with reintervention were identified using univariate cox regression analysis.ResultsEighty‐one PA stents were placed in 68 patients. The procedural complication rate was 4.4%. During a median follow‐up period of 6 years (interquartile range [IQR] 0.9‐12.7), 30 patients (44%) underwent reintervention on the stented PA with a median time to first reintervention of 2.6 years (IQR 0.7–4.4 years). The first reintervention was surgical in 30% and catheter‐based in 70%. Risk factors for reintervention included age < 18 months (Hazard ratio [HR] 2.97, P = 0.005) and body surface area < 0.47 m2 (HR 3.20, P = 0.003) at the time of stent implantation, and the presence of multiple aortopulmonary collaterals in patients with tetralogy of Fallot (HR 4.61, P = 0.003).ConclusionsIntraoperative PA stent implantation is a safe and effective alternative to percutaneous stent implantation and offers several advantages, including the ability to implant adult‐size stents in small patients while avoiding injury to peripheral vessels, to position stents to facilitate future percutaneous stent redilation, and to access the PAs directly, which eliminates radiation exposure. © 2017 Wiley Periodicals, Inc.
Purification and Characterization of an Enone Reductase from Sporidiobolus salmonicolor TPU 2001 Reacting with Large Monocyclic Enones
Authors: Yamamoto Kazunori , Oku Yuko , Ina Atsutoshi , Izumi Atsushi , Doya Masaharu , Ebata Syuji , Asano Yasuhisa 
Published: May 2017

AbstractWe discovered a novel enone reductase from Sporidiobolus salmonicolor TPU 2001 (SsERD) and expressed the gene in Escherichia coli. The enzyme catalyzed the reduction of (E)‐3‐methylcyclopentadec‐2‐en‐1‐one (E‐2), cyclopentadec‐2‐en‐1‐one (3), and cyclododec‐2‐en‐1‐one (4) to (S)‐muscone (S‐1), cyclopentadecan‐1‐one (5), and cyclododecan‐1‐one (6), respectively. The apparent Km and Vmax values for E‐2 were estimated to be 4.9±0.4 μm and 100±1.4 nmol min−1 mg−1, respectively. The enzyme was specific to NADPH, and cysteine residues strongly affected the enzyme activity. The enzyme exhibited the highest activity at pH 8.0 and high stability in the pH range from 4.5 to 11.0. Using 10 mU of the enzyme, S‐1 was synthesized from 0.1 mm E‐2 with 94.8 % yield and 100 % enantiomeric excess by incubation at pH 7.0 and 30 °C for 60 min. We further successfully constructed an enone reductase with high specific activity by mutation of SsERD. The Y67A variant from SsERD exhibited 4.5 times higher specific activity and 3 times higher catalytic efficiency toward E‐2. This is the first report of an enzyme catalyzing the reduction of carbon–carbon double bond of large monocyclic enones.
One‐Pot Biocatalytic Double Oxidation of α‐Isophorone for the Synthesis of Ketoisophorone
Authors: Tavanti Michele , Parmeggiani Fabio , Castellanos J. Rubén Gómez , Mattevi Andrea , Turner Nicholas J. 
Published: May 2017

AbstractThe chemical synthesis of ketoisophorone, a valuable building block of vitamins and pharmaceuticals, suffers from several drawbacks in terms of reaction conditions and selectivity. Herein, the first biocatalytic one‐pot double oxidation of the readily available α‐isophorone to ketoisophorone is described. Variants of the self‐sufficient P450cam‐RhFRed with improved activity have been identified to perform the first step of the designed cascade (regio‐ and enantioselective allylic oxidation of α‐isophorone to 4‐hydroxy‐α‐isophorone). For the second step, the screening of a broad panel of alcohol dehydrogenases (ADHs) led to the identification of Cm‐ADH10 from Candida magnoliae. The crystal structure of Cm‐ADH10 was solved and docking experiments confirmed the preferred position and geometry of the substrate for catalysis. The synthesis of ketoisophorone was demonstrated both as a one‐pot two‐step process and as a cascade process employing designer cells co‐expressing the two biocatalysts, with a productivity of up to 1.4 g L−1 d−1.
A Titanium Dioxide Supported Gold Nanoparticle Catalyst for the Selective N‐Formylation of Functionalized Amines with Carbon Dioxide and Hydrogen
Authors: Mitsudome Takato , Urayama Teppei , Fujita Shu , Maeno Zen , Mizugaki Tomoo , Jitsukawa Koichiro , Kaneda Kiyotomi 
Published: May 2017

AbstractA TiO2‐supported, gold nanoparticle catalyst was found to allow the N‐formylation of various amines, including normally unreactive anilines, by using CO2 as the carbonyl source under a H2 atmosphere. A series of reducible functional groups, such as olefins, halogens, carbonyls, carbamates, and cyano moieties, were completely retained during the formylation, which proved the highly selective nature of the formylation reaction. The catalyst was also found to be reusable without any loss of activity or selectivity.