bluuebunny/crossref_metadata_2025 huggingface dataset:
A duration model analysis of consumer preferences and determinants of video game consumption
Authors: Kaimann Daniel , Stroh‐Maraun Nadja , Cox Joe
Published: March 2018

Despite the enormous revenues generated by the video game industry in recent years, relatively little research has been undertaken into consumer preferences and the determinants of video game consumption. This study addresses this deficiency through the analysis of data from a popular online video game that includes historic behavioural information for 1,408 consumers participating in 728,811 unique rounds of gameplay. We analyse these data with the goal of estimating determinants of the aggregate amount of time that a consumer spends playing the game. Through the estimation of duration models, we show that less experienced consumers are less likely to continue playing the game at any given point, possibly due to having achieved mastery and becoming bored. However, we also find that consumers tend to play the game for longer periods when using a wider range of character roles and vehicles, implying that a consumer's interest can be maintained through exposure to greater variety. Our results represent the first such evidence on in‐game consumer preferences, which has important implications for video game consumption through optimisation of gameplay experiences to satisfy these preferences.
Reaction Mechanism of Prephenate Dehydrogenase from the Alternative Tyrosine Biosynthesis Pathway in Plants
Authors: Holland Cynthia K. , Jez Joseph M.
Published: March 2018

Unlike metazoans, plants, bacteria, and fungi retain the enzymatic machinery necessary to synthesize the three aromatic amino acids l‐phenylalanine, l‐tyrosine, and l‐tryptophan de novo. In legumes, such as soybean, alfalfa, and common bean, prephenate dehydrogenase (PDH) catalyzes the tyrosine‐insensitive biosynthesis of 4‐hydroxyphenylpyruvate, a precursor to tyrosine. The three‐dimensional structure of soybean PDH1 was recently solved in complex with the NADP+ cofactor. This structure allowed for the identification of both the cofactor‐ and ligand‐binding sites. Here, we present steady‐state kinetic analysis of twenty site‐directed active‐site mutants of soybean (Glycine max) PDH compared to wild‐type. Molecular docking of the substrate, prephenate, into the active site of the enzyme revealed its potential interactions with the active site residues and made a case for the importance of each residue in substrate recognition and/or catalysis, most likely through transition state stabilization. Overall, these results suggested that the active site of the enzyme is highly sensitive to any changes, as even subtle alterations substantially reduced the catalytic efficiency of the enzyme.
Characterization of the Actinonin Biosynthetic Gene Cluster
Authors: Wolf Felix , Leipoldt Franziska , Kulik Andreas , Wibberg Daniel , Kalinowski Jörn , Kaysser Leonard
Published: March 2018

The hydroxamate moiety of the natural product actinonin mediates inhibition of metalloproteinases because of its chelating properties towards divalent cations in the active site of those enzymes. Owing to its antimicrobial activity, actinonin has served as a lead compound for the development of new antibiotic drug candidates. Recently, we identified a putative gene cluster for the biosynthesis of actinonin. Here, we confirm and characterize this cluster by heterologous pathway expression and gene‐deletion experiments. We assigned the biosynthetic gene cluster to actinonin production and determine the cluster boundaries. Furthermore, we establish that ActI, an AurF‐like oxygenase, is responsible for the N‐hydroxylation reaction that forms the hydroxamate warhead. Our findings provide the basis for more detailed investigations of actinonin biosynthesis.
Impact of HAS‐BLED score to predict trans femoral transcatheter aortic valve replacement outcomes
Authors: Honda Yohsuke , Yamawaki Masahiro , Araki Motoharu , Tada Norio , Naganuma Toru , Yamanaka Futoshi , Watanabe Yusuke , Yamamoto Masanori , Shirai Shinichi , Hayashida Kentaro ,   on behalf of the OCEAN‐TAVI investigators
Published: March 2018

Background

Predictors of bleeding and mortality after trans femoral transcatheter aortic valve replacement (TF‐TAVR) has not been thoroughly investigated.

Objective

The aim of this study was to assess whether Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile INR, Elderly, Drugs/alcohol concomitantly (HAS‐BLED) score has predictive value for bleeding and mortality in patients after TAVR.

Methods

Between October 2013 and April 2016, 969 patients underwent TF‐TAVI were prospectively included in the OCEAN‐TAVI registry from Japan. The primary outcomes were severe bleeding (including life‐threatening and major bleeding defined in The Valve Academic Research Consortium‐2 criteria) and mortality within 1 year after TAVR.

Results

Elderly (84 ± 5 years) and high surgical risk patients (The Society of Thoracic Surgery Risk Score 6.7 [4.6–9.3]) were enrolled. Severe bleeding and mortality had occurred in 177 patients (18.2%) and 66 patients (6.8%), respectively. On multivariate analysis, HAS‐BLED score was associated with severe bleeding (hazard ratio [HR], 1.82; 95% confidence interval [CI], 1.41–2.00; p < 0.001) and mortality (HR, 2.04, 95% CI, 1.56–2.69, P < 0.001). A HAS‐BLED score threshold of 4 points (area under the curve 0.71 for severe bleeding, 0.72 for mortality) predicted a higher rate of severe bleeding (25.3% vs. 14.4%, P < 0.001) and mortality (16.2% vs. 4.0%, P < 0.001).

Conclusions

HAS‐BLED score could predict the risk of severe bleeding and mortality in patients who underwent TF‐TAVR independent of the presence of atrial fibrillation.
An algorithmic approach for the management of ostial right coronary artery chronic total occlusions
Authors: Avran Alexandre , Boukhris Marouane , Drogoul Laurent , Brilakis Emanouil S
Published: March 2018

Treatment of ostial chronic total occlusions (CTOs) of the right coronary artery (RCA) can be challenging. We present an algorithmic approach to the management of such lesions that incorporates all contemporary equipment and techniques. If the RCA ostium can be engaged with a guide catheter then antegrade crossing attempts should be performed. If the antegrade guidewire enters the subintimal space, re‐entry into the distal true lumen is performed provided that the antegrade guide catheter provides enough support. If re‐entry cannot be achieved, the antegrade wire is left in place to facilitate retrograde recanalization attempts (usually performed using the reverse controlled antegrade and retrograde tracking and dissection—reverse CART—technique). If the RCA ostium cannot be engaged with a guide catheter (for example in flush ostial occlusions) or if the guide catheter does not provide sufficient support, a primary retrograde approach is required, aiming for retrograde guidewire puncture into the aorta, followed by snaring and externalization. Retrograde guidewire puncture can be challenging, requiring use of stiff, highly penetrating guidewires or occasionally use of the Carlino technique. The aforementioned algorithm can facilitate crossing of ostial RCA CTOs.
The first transapical transcatheter aortic valve‐in‐valve implantation using the J‐valve system into a failed biophysio aortic prosthesis in a patient with high risk of coronary obstruction
Authors: Ye Jian , Lee Arthur J. , Blanke Philipp , Webb John
Published: March 2018

We report the first successful valve‐in‐valve (ViV) implantation into a failed Edwards Biophysio surgical prosthesis (Edwards Lifesciences, Irvine, CA) and also the first use of the J‐Valve system (Jie Cheng Medical Technologies, Suzhou, China) in a ViV configuration. A 77‐year old male had symptomatic severe aortic stenosis secondary to failure of a 25 mm Biophysio bioprosthetic valve implanted 11 years previously, along with concomitant coronary artery bypass grafting. Transthoracic echocardiography (TTE) revealed calcified leaflets, a mean aortic gradient of 50 mm Hg, and an estimated valve area of 0.9 cm2 with no aortic insufficiency. The patient had low coronary ostial height with the right coronary artery arising only 8.5 mm from the valve annulus and the left main coronary artery arising only 9.4 mm from the valve annulus. Risk of coronary ostial obstruction was especially concerning in context of both the patient's extremely low coronary ostial height and the unique structure of the Biophysio valve. Under general anesthesia, transapical transcatheter aortic ViV implantation with a 25 mm J‐Valve was performed in a hybrid operating room. The J‐Valve prosthesis was deployed in the 25 mm Biophysio surgical valve without difficulty or complications. There were no intraoperative or postoperative complications. The patient was discharged home after 3 days. TTE at 1 year showed a mean aortic valve gradient of 14 mm Hg, and no aortic insufficiency. This case demonstrated that J‐Valve implantation may be a new option for patients at high risk for coronary obstruction.
Degenerative mitral regurgitation predicts worse outcomes in patients undergoing transcatheter aortic valve replacement
Authors: Kindya Bryan , Ouzan Elisha , Lerakis Stamatios , Gonen Erhan , Babaliaros Vasilis , Karayel Eren , Thourani Vinod H. , Gotsman Israel , Devireddy Chandan M. , Danenberg Haim D. , Leshnower Bradley G. , Beeri Ronen , Ko Yi‐An , Gilon Dan , Ahmed Hina , Liu Chang , Lotan Chaim , Mavromatis Kreton
Published: March 2018

Objectives

To evaluate the role mitral regurgitation (MR) etiology and severity play in outcomes for patients undergoing transcatheter aortic valve replacement (TAVR).

Background

Multiple prior studies have investigated the influence of MR severity on outcomes for patients undergoing TAVR. Less has been published regarding the effects of MR etiology on outcomes, including its impact on heart failure hospitalization.

Methods

Two hundred and seventy patients undergoing TAVR at 2 hospitals were enrolled. Each patient had a baseline and follow‐up (within 30 days of TAVR) echocardiogram that was analyzed. MR was graded as none, mild, moderate, or severe, as well as functional or degenerative. We compared patient outcomes, including death and heart failure hospitalization, among none‐mild MR, moderate‐severe functional MR, and moderate‐severe degenerative MR groups.

Results

Two hundred and seventy patients underwent TAVR, reducing mean aortic valve gradients from 45 ± 15 mm Hg to 9 ± 4 mm Hg. On multivariable analysis, only patients with moderate‐severe degenerative MR had decreased survival free of death or CHF hospitalization compared to those with none‐mild MR (P = .011). Subanalysis showed patients with moderate‐severe degenerative MR were more likely to be hospitalized for heart failure at 2 years compared to those with moderate‐severe functional MR (P = .02). Patients with moderate‐severe degenerative MR were also less likely to have improvement in MR severity at follow up (P = .01).

Conclusions

Special consideration should be given to patients with moderate‐severe degenerative MR undergoing TAVR. As transcatheter approaches for mitral valve repair and replacement continue to evolve, moderate‐severe degenerative MR patients may benefit from consideration of double valve intervention.
Patent foramen ovale (PFO) closure versus medical therapy for prevention of recurrent stroke in patients with prior cryptogenic stroke: A systematic review and meta‐analysis of randomized controlled trials
Authors: Akobeng Anthony K. , Abdelgadir Ibtihal , Boudjemline Younes , Hijazi Ziyad M.
Published: March 2018

Objectives

We performed a systematic review and meta‐analysis of randomized controlled trials to assess the effect of closure of a patent foramen ovale (PFO) compared with medical therapy for the prevention of stroke in patients with prior cryptogenic stroke.

Background

The role of PFO closure in reducing risk of stroke in patients with prior cryptogenic stroke has been controversial.

Methods

We searched PubMed, Embase, CINAHL, and CENTRAL for randomized trials investigating PFO closure versus medical therapy. We assessed trial bias and the quality of evidence for main outcomes was rated using GRADE. The primary outcome of interest was the occurrence of stroke. Estimates of effect were pooled with a random‐effects model. This study is registered with PROSPERO (CRD42017081579).

Results

We included five trials, comprising data for 3,440 adults randomized to receive PFO closure (n = 1,829) or medical therapy (n = 1,611). Mean follow‐up ranged from 2 years to 5.4 years across the trials. Patients treated with PFO closure had a lower risk of stroke (RR 0.39, 95% CI 0.18–0.88, I2 = 57%, P = 0.02) compared with those treated with medical therapy. Subgroup analyses showed that the beneficial effect of PFO closure on a composite outcome of cerebrovascular events is more pronounced in patients with a large PFO shunt (RR 0.25, 95% CI 0.12–0.54, I2 = 0%, P = 0.0004), male patients (RR 0.34, 95% CI 0.15–0.75, I2 = 36%, P = 0.07), and those aged ≤45 years (RR 0.35, 95% CI 0.15–0.79, I2 = 0%, P = 0.01).

Conclusions

PFO closure reduced risk of stroke compared with medical therapy. PFO closure is a therapeutic option that should be offered to adults with cryptogenic stroke.
Reduction of catheter kinks and knots via radial approach
Authors: Ben‐Dor Itsik , Rogers Toby , Satler Lowell F. , Waksman Ron
Published: March 2018

Coronary angiography and percutaneous coronary intervention using the radial approach are becoming more frequent. Pronounced guide catheter manipulation in cases with tortuous access routes may lead to severe catheter kinking or knotting. The purpose of this review article is to present several techniques to resolve radial access catheter knots and kinks. First, simple maneuvers such as gentle traction, rotation, and guidewire advancement can often resolve minor kinking; however, complex loops and kinks are often not reversible with these simple maneuvers. Second, fixing the distal catheter tip using external compression, encasing the knot with a larger sheath, or untwisting the knot with hydraulic pressure can be useful. Finally, internal fixation by grasping the kinked catheter with a snare introduced via the femoral artery allows both ends of the catheter to be rotated in opposite directions to untwist the catheter for safe removal.
Stepwise management of hepatocellular carcinoma associated with Abernethy syndrome
Authors: Christou Niki , Dib Nabil , Chuffart Etienne , Taibi Abdelkader , Durand‐Fontanier Sylvaine , Valleix Denis , Mathonnet Muriel
Published: March 2018

Key Clinical Message

Patients with congenital agenesis of the portal vein may develop hepatocellular tumors due to enhanced arterial blood flow. These tumors may be benign (FNH, adenomas) or malignant (hepatoblastoma, HCC). Liver resection can be proposed, and preoperative arterial embolization may decrease blood loss during surgery. Liver transplantation with PV reconstruction is also an option.
Palladium‐Catalyzed C2−H Arylation of Unprotected (N−H)‐Indoles “On Water” Using Primary Diamantyl Phosphine Oxides as a Class of Primary Phosphine Oxide Ligands
Authors: Moncea Oana , Poinsot Didier , Fokin Andrey A. , Schreiner Peter R. , Hierso Jean‐Cyrille
Published: March 2018

We present the Pd‐catalyzed arylation of (N−H)‐indoles with functionalized haloarenes “on water” using hitherto untested primary diamantyl phosphine oxides (PPO) as ligands. Remarkable C2−H arylation selectivity was achieved by employing functionalized iodoarenes and N‐unprotected indoles. We provide evidence that the in situ generated oxide of (9‐hydroxydiamant‐4‐yl)phosphine L1 is key for the reaction efficiency by comparing a set of diamantane‐based compounds structurally related to L1. Our results demonstrate the power of the new PPO ligands for the C−H functionalization of unprotected (N−H)‐heterocycles.
Oxa‐Michael Addition to α,β‐Unsaturated Nitriles: An Expedient Route to γ‐Amino Alcohols and Derivatives
Authors: Guo Beibei , Zijlstra Douwe S. , de Vries Johannes G. , Otten Edwin
Published: March 2018

Water addition to α,β‐unsaturated nitriles would give facile access to the β‐hydroxy‐nitriles, which in turn can be hydrogenated to the γ‐amino alcohols. We have previously shown that alcohols readily add in 1,4‐fashion to these substrates using Milstein's Ru(PNN) pincer complex as catalyst. However, attempted water addition to α,β‐unsaturated nitriles gave the 3‐hydroxynitriles in mediocre yields. On the other hand, addition of benzyl alcohol proceeded in excellent yields for a variety of β‐substituted unsaturated nitriles. Subsequent treatment of the benzyl alcohol addition products with TMSCl/FeCl3 resulted in the formation of 3‐hydroxy‐alkylnitriles. The 3‐benzyloxy‐alkylnitriles obtained from oxa‐Michael addition also could be hydrogenated directly in the presence of acid to give the amino alcohols as their HCl salts in excellent yields. Hydrogenation under neutral conditions gave a mixture of the secondary and tertiary amines. Hydrogenation in the presence of base and Boc‐anhydride gave the orthogonally bis‐protected amino alcohols, in which the benzyl ether can subsequently be cleaved to yield Boc‐protected amino alcohols. Thus, a variety of molecular scaffolds with a 1,3‐relationship between O‐ and N‐functional group is accessible starting from oxa‐Michael addition of benzyl alcohol to α,β‐unsaturated nitriles.
Hierarchical MnO2 Located on Carbon Nanotubes for Enhanced Electrochemical Performance
Authors: Li Shaohui , Gao Lin , Wang Lichuan , Wang Mingkui , Shen Yan
Published: March 2018

Abstract: Herein, we assembled an asymmetric supercapacitor (ASC) with high energy and power density based on porous MnO2/nitrogen‐doped carbon nanotubes (MnO2/NCNTs) in the positive electrode and chemical activated of nitrogen‐doped carbon nanotubes (ANCNTs) in the negative electrode. The ANCNTs//MnO2/NCNTs ASC device operates reversibly at a high voltage of 2.0 V in 1.0 M Na2SO4 and exhibits a high energy density of 37.2 Wh kg−1, which can be included in the top category of supercapacitors. More importantly, the supercapacitor exhibits impressive rate capability (high power density of 15100 W kg−1 at an energy density of 12.8 Wh kg−1) and exceptional cycling stability with 95.2 % capacitance retention after 3000 cycles. These attractive results indicate the potential for efficient energy storage devices.
Reversible Delithiation of Disordered Rock Salt LiVO2
Authors: Baur Christian , Chable Johann , Klein Franziska , Chakravadhanula Venkata Sai Kiran , Fichtner Maximilian
Published: March 2018

A rigid crystal lattice, in which cations occupy specific positions, is generally regarded as a critical requirement to enable Li+ diffusion in the bulk of conventional cathode materials, whereas disorder is generally considered as detrimental. Herein, we demonstrate that facile and reversible insertion and extraction of Li+ is possible with LiVO2, a new cation‐disordered rock salt compound (space group: Fm
m), which is, to the best of our knowledge, described for the first time. This new polymorph of LiVO2 is synthesized by mechanical alloying. Rietveld refinements of the X‐ray diffractions patterns and SAED (selected‐area electron diffraction) patterns attested the formation of the disordered LiVO2 rock salt phase. Galvanostatic cycling experiments were employed to characterize the electrochemical performance of the material, demonstrating that reversible cycling over 100 cycles with a discharge capacity around 100 mAh g−1 is possible.
Elucidating the Structure–Reactivity Correlations of Phenothiazine‐Based Fluorescent Probes toward ClO−
Authors: Wang Shichao , Zhang Boyu , Wang Wenjing , Feng Gang , Yuan Daqiang , Zhang Xuanjun
Published: March 2018

In this work, with the aim of developing effective molecular probes and investigating the structure–reactivity correlation, a short series of phenothiazine‐based fluorescent probes are designed for the detection of ClO− with differing electron push‐pull groups. Sensing experiment results and single‐crystal X‐ray analysis with the aid of time‐dependent DFT (TD‐DFT) calculations reveal that substituting groups with increasing electron‐withdrawing ability can increase the dihedral angle of the phenothiazine moiety and reduce the gap energy of the probes, leading to enhanced reactivity toward ClO−. Both PT1 and PT2 show two‐color switching upon detection of ClO−. PT1, with the strong electron‐donating group thiophene, shows a fluorescence color switch from salmon to blue. PT2, with a medium electron‐donating/accepting group benzothiazole, shows a fluorescence color switch from red to green. However, both PT1 and PT2 show almost no response to ONOO−. Through the introduction of strong electron‐withdrawing ketone combined with a cyano group, PT3 shows a cyan emission upon detection of ClO− and weak red emission upon detection of ONOO−. HRMS and 1H NMR results confirm that PT1 and PT2 have the same sensing mode, in which the divalent sulfur of phenothiazine can be oxidized to sulfoxide by ClO−. Upon reaction with ClO−, PT3 experiences two‐step reactions. It is first oxidized into the sulfone structure by ClO−, and then transformed into sulfoxide phenothiazine aldehyde. Upon encountering ONOO−, PT3 changes into an aldehyde structure and some nonfluorescent byproducts. Owing to their special selectivity and high sensitivity, PT1 and PT2 are applied to image the endogenous ClO− in macrophage cells and zebrafish larvae. This study is expected to provide useful guidelines for probe design for various applications.
A Systematic Protocol for Benchmarking Guest–Host Interactions by First‐Principles Computations: Capturing CO2 in Clathrate Hydrates
Authors: Arismendi‐Arrieta Daniel J. , Valdés Álvaro , Prosmiti Rita
Published: March 2018

Clathrate hydrates of CO2 have been proposed as potential molecular materials in tackling important environmental problems related to greenhouse gases capture and storage. Despite the increasing interest in such hydrates and their technological applications, a molecular‐level understanding of their formation and properties is still far from complete. Modeling interactions is a challenging and computationally demanding task, essential to reliably determine molecular properties. First‐principles calculations for the CO2 guest in all sI, sII, and sH clathrate cages were performed, and the nature of the guest–host interactions, dominated by both hydrogen‐bond and van der Waals forces, was systematically investigated. Different families of density functionals, as well as pairwise CO2@H2O model potentials versus wavefunction‐based quantum approaches were studied for CO2 clathrate‐like systems. Benchmark energies for new distance‐dependent datasets, consisting of potential energy curves sampling representative configurations of the systems at the repulsive, near‐equilibrium, and asymptotic/long‐range regions of the full‐dimensional surface, were generated, and a general protocol was proposed to assess the accuracy of such conventional and modern approaches at minimum and non‐minimum orientations. Our results show that dispersion interactions are important in the guest–host stabilization energies of such clathrate cages, and the encapsulation of the CO2 into guest‐free clathrate cages is always energetically favorable. In addition, the orientation of CO2 inside each cage was explored, and the ability of current promising approaches to accurately describe non‐covalent CO2@H2O guest–host interactions in sI, sII, and sH clathrates was discussed, providing information for their applicability to future multiscale computer simulations.
Structural Analysis of a GalNAc‐T2 Mutant Reveals an Induced‐Fit Catalytic Mechanism for GalNAc‐Ts
Authors: de las Rivas Matilde , Coelho Helena , Diniz Ana , Lira‐Navarrete Erandi , Compañón Ismael , Jiménez‐Barbero Jesús , Schjoldager Katrine T. , Bennett Eric P. , Vakhrushev Sergey Y. , Clausen Henrik , Corzana Francisco , Marcelo Filipa , Hurtado‐Guerrero Ramon
Published: March 2018

The family of polypeptide N‐acetylgalactosamine (GalNAc) transferases (GalNAc‐Ts) orchestrates the initiating step of mucin‐type protein O‐glycosylation by transfer of GalNAc moieties to serine and threonine residues in proteins. Deficiencies and dysregulation of GalNAc‐T isoenzymes are related to different diseases. Recently, it has been demonstrated that an inactive GalNAc‐T2 mutant (F104S), which is not located at the active site, induces low levels of high‐density lipoprotein cholesterol (HDL‐C) in humans. Herein, the molecular basis for F104S mutant inactivation has been deciphered. Saturation transfer difference NMR spectroscopy experiments demonstrate that the mutation induces loss of binding to peptide substrates. Analysis of the crystal structure of the F104S mutant bound to UDP‐GalNAc (UDP=uridine diphosphate), combined with molecular dynamics (MD) simulations, has revealed that the flexible loop is disordered and displays larger conformational changes in the mutant enzyme than that in the wild‐type (WT) enzyme. 19F NMR spectroscopy experiments reveal that the WT enzyme only reaches the active state in the presence of UDP‐GalNAc, which provides compelling evidence that GalNAc‐T2 adopts a UDP‐GalNAc‐dependent induced‐fit mechanism. The F104S mutation precludes the enzyme from achieving the active conformation and concomitantly binding peptide substrates. This study provides new insights into the catalytic mechanism of the large family of GalNAc‐Ts and how these enzymes orchestrate protein O‐glycosylation.
Directional Self‐Sorting with Cucurbit[8]uril Controlled by Allosteric π–π and Metal–Metal Interactions
Authors: Kotturi Kondalarao , Masson Eric
Published: March 2018

To maximize Coulombic interactions, cucurbit[8]uril (CB[8]) typically forms ternary complexes that distribute the positive charges of the pair of guests (if any) over both carbonylated portals of the macrocycle. We present here the first exception to this recognition pattern. Platinum(II) acetylides flanked by 4′‐substituted terpyridyl ligands (tpy) form 2:1 complexes with CB[8] in an exclusively stacked head‐to‐head orientation in a water/acetonitrile mixture. The host encapsulates the pair of tpy substituents, and both positive Pt centers sit on top of each other at the same CB[8] rim, leaving the other rim free of any interaction with the guests. This dramatic charge imbalance between the CB[8] rims would be electrostatically penalizing, were it not for allosteric π–π interactions between the stacked tpy ligands, and possible metal‐metal interactions between both Pt centers. When both tpy and acetylides are substituted with aryl units, the metal‐ligand complexes form 2:2 assemblies with CB[8] in aqueous medium, and the directionality of the assembly (head‐to‐head or head‐to‐tail) can be controlled, both kinetically and thermodynamically.
Synthesis and Bioactivity of Polymer‐Based Synthetic Mimics of Antimicrobial Peptides (SMAMPs) Made from Asymmetrically Disubstituted Itaconates
Authors: Boschert David , Schneider‐Chaabane Alexandra , Himmelsbach Andreas , Eickenscheidt Alice , Lienkamp Karen
Published: March 2018

A series of asymmetrically disubstituted diitaconate monomers is presented. Starting from itaconic anhydride, functional groups could be placed selectively at the two nonequivalent carbonyl groups. By using 2D NMR spectroscopy, it was shown that the first functionalization step occurred at the carbonyl group in the β position to the double bond. These monomers were copolymerized with N,N‐dimethylacrylamide (DMAA) to yield polymer‐based synthetic mimics of antimicrobial peptides (SMAMPs). They were obtained by free radical polymerization, a metal‐free process, and still maintained facial amphiphilicity at the repeat unit level. This eliminates the need for laborious metal removal and is advantageous from a regulatory and product safety perspective. The poly(diitaconate‐co‐DMAA) copolymers obtained were statistical to alternating, and the monomer feed ratio roughly matched that of the repeat unit content of the copolymers. Investigations of varied R group hydrophobicity, repeat unit ratio, and molecular mass on antimicrobial activity against Escherichia coli and on compatibility with human keratinocytes showed that the polymers with the longest R groups and lowest DMAA content were the most antimicrobial and hemolytic. This is in agreement with the biological activity of previously reported SMAMPs. Thus, the design concept of facial amphiphilicity has successfully been transferred, but the selectivity of these polymers for bacteria over mammalian cells still needs to be optimized.
How psychic distance and opportunity perceptions affect entrepreneurial firm internationalization
Authors: Bhowmick Sanjay
Published: March 2018

Psychic distance, now established as an individual perceptual construct, is so far a partial explanation of internationalization processes of entrepreneurial firms. Opportunity in foreign markets, although considered important, has hitherto been an assumption rather than explored as an explanatory factor in internationalization theories. Through qualitative data from technology entrepreneurs from New Zealand this study considers opportunity, like psychic distance, as an individual perceptual construct and posits that a combination of opportunity and psychic distance perceptions better explains entrepreneurial internationalization action/intention decisions. The explicit combination proposed is “opportunity‐distance quotient” and signifies a shift from psychic distance obstacles based explanations to an opportunity‐psychic distance interaction based exploration of entrepreneurial internationalization. Limitations of the study and further research are discussed. Copyright © 2018 ASAC. Published by John Wiley & Sons, Ltd.
Quantification of near‐wall hemodynamic risk factors in large‐scale cerebral arterial trees
Authors: Ghaffari Mahsa , Alaraj Ali , Du Xinjian , Zhou Xiaohong Joe , Charbel Fady T. , Linninger Andreas A.
Published: March 2018

Detailed hemodynamic analysis of blood flow in pathological segments close to aneurysm and stenosis has provided physicians with invaluable information about the local flow patterns leading to vascular disease. However, these diseases have both local and global effects on the circulation of the blood within the cerebral tree. The aim of this paper is to demonstrate the importance of extending subject‐specific hemodynamic simulations to the entire cerebral arterial tree with hundreds of bifurcations and vessels, as well as evaluate hemodynamic risk factors and waveform shape characteristics throughout the cerebral arterial trees. Angioarchitecture and in vivo blood flow measurement were acquired from healthy subjects and in cases with symptomatic intracranial aneurysm and stenosis. A global map of cerebral arterial blood flow distribution revealed regions of low to high hemodynamic risk that may significantly contribute to the development of intracranial aneurysms or atherosclerosis. Comparison of pre‐intervention and post‐intervention of pathological cases further shows large angular phase shift (~33.8°), and an augmentation of the peak‐diastolic velocity. Hemodynamic indexes of waveform analysis revealed on average a 16.35% reduction in the pulsatility index after treatment from lesion site to downstream distal vessels. The lesion regions not only affect blood flow streamlines of the proximal sites but also generate pulse wave shift and disturbed flow in downstream vessels. This network effect necessitates the use of large‐scale simulation to visualize both local and global effects of pathological lesions.
All‐Optical Switching and Two‐States Light‐Controlled Coherent‐Incoherent Random Lasing in a Thiophene‐Based Donor‐Acceptor System
Authors: Szukalski Adam , Ayadi Awatef , Haupa Karolina , El‐Ghayoury Abdelkrim , Sahraoui Bouchta , Mysliwiec Jaroslaw
Published: March 2018

We describe herein the synthesis and characterization of a thiophene‐based donor‐acceptor system, namely (E)‐2‐(4‐nitrostyryl)‐5‐phenylthiophene (Th‐pNO2), which was prepared under Horner‐Wadsworth‐Emmons conditions. The UV/Vis absorption bands, including the intramolecular charge transfer (ICT) band, were fully assigned using DFT and TD‐DFT computations. The results of both efficient third‐order nonlinear optical properties and light‐amplification phenomena are presented. Investigations of photoinduced birefringence (PIB) in optical Kerr effect (OKE) experiments showed a great potential for this particular compound as an efficient, fully reversible, and fast optical switch. Time constants for the observed trans‐cis‐trans molecular transitions are in the range of microseconds and give a competitive experimental result for the well‐known and exploited azobenzene derivatives. Random lasing (RL) investigations confirmed that this organic system is potentially useful to achieve strong light enhancement, observed as a multimode lasing action. Both RL and OKE measurements indicate that this material is a representative of thiophene derivatives, which can be utilized to fabricate fast all‐optical switches or random lasers (light amplifiers).
Supramolecular Confinement within Chitosan Nanocomposites Enhances Singlet Oxygen Generation
Authors: Naim Khalid , Nair Sreejisha T. , Yadav Pranjali , Shanavas Asifkhan , Neelakandan Prakash P.
Published: March 2018

The synthesis of water‐soluble chitosan nanocomposites incorporating BODIPY and the investigation of their photosensitization properties is reported. It was observed that the singlet oxygen generation capability of nanocomposites containing a mixture of BODIPY and iodine‐containing molecules are higher than that of the nanocomposites containing BODIPY alone. It is hypothesized that the supramolecular interactions between BODIPY and iodine‐containing molecules confined within the nanocomposites lead to the enhanced singlet oxygen generation.
Environmental policy and sustainable development: An empirical study on carbon reduction among Chinese enterprises
Authors: Yu Hui‐Cheng , Tsai Bor‐Yuan
Published: March 2018

This study mainly examined the influences of enterprises' carbon reduction behaviors on their sustainable development, and investigated the effects on sustainable development of carbon emission reduction by state‐owned enterprises (SOEs) from high‐carbon‐emission industries in China. Data were coded through a content analysis procedure, followed by regression analysis. Analysis of variance results revealed that SOEs and high‐carbon‐emission industries emphasize realizing carbon reduction more than do privately owned enterprises and non‐high‐carbon‐emission industries, with significant between‐groups differences observed between these enterprises and industries. Regression results indicated that carbon reduction positively and significantly influences corporate sustainable development, suggesting that carbon reduction is beneficial to both the ecological environment and corporate sustainable development. However, carbon reduction negatively yet insignificantly influences the sustainable development of SOEs in industries with high carbon emissions. The empirical findings may serve as a critical reference for China, which is moving toward a low‐carbon economy.
Insight into the Metal Content–Structure–Property Relationship in Lanthanide Metal–Organic Frameworks: Optical Studies, Magnetism, and Catalytic Performance
Authors: Gomez Germán E. , Brusau Elena V. , Sacanell Joaquín , Soler Illia Galo J. A. A. , Narda Griselda E.
Published: March 2018

Two series of metal–organic frameworks (MOFs) based on a flexible ligand and trivalent lanthanides were obtained hydrothermally in order to explore their optical properties at low temperature, magnetism, and catalytic activity in relation to their structural features. A multisite analysis was performed according to the 4f–4f transitions. Moreover, the heterogeneous catalytic activity of the series was evaluated in one‐pot cyanosilylation with benzaldehyde as substrate. Recyclability, structure conservation, and catalytic efficiency were also evaluated and compared with those of analogous compounds.
Switchable Heteroleptic Mononuclear Iron(II) Complexes as Versatile Molecular Building Block
Authors: Baldé Chérif , Paradis Nicolas , Desplanches Cédric , Chastanet Guillaume
Published: March 2018

A series of photoswitchable precursors based on [Fe(NCX)2L(L′)2], where X = S or Se, L is a bidentate ligand (phenanthroline or bipyrimidine), and L′ a monodentate ligand such as a pyridine or picoline derivative, were synthesized and their spin crossover (SCO) properties investigated in detail. The thermal and light‐induced magnetic properties of a family of [Fe(NCS)2L(py)2] [py = pyridine and L = bipyrimidine (1) or phenanthroline (phen) (2)] is reported. The [Fe(NCX)2(phen)(L′)2] compounds were further explored by changing the counteranion from NCS– to NCSe– (3) or by replacing pyridine with 4‐picoline (4) or 4‐ethylpyridine (5). Complexes 1–4 exhibit thermal and light‐induced SCO, while 5 remains in the high‐spin state. The kinetics governing the photoinduced back‐conversion was investigated for compounds 2 and 4. Complex 2 exhibits LIESST relaxation kinetics involving strongly cooperative (sigmoidal) behavior, whereas complex 4 displays a stretched exponential shape, typical for broad distributions of relaxation times. These results are discussed on the basis of the steric hindrance due to bulkiness and the electronic influence of the substituent effects on the magnetic and photomagnetic properties of mononuclear iron(II) complexes.
Diradical Character and Second Hyperpolarizability of Alkaline Earth Metal Inverse Sandwich Complexes Involving Cyclopentadienyl and Cyclooctatetraene Ligands
Authors: Takamuku Shota , Nakano Masayoshi
Published: March 2018

Using strong‐correlated quantum chemical calculations, we have revealed the relationship between diradical character y and second hyperpolarizability γ [third‐order nonlinear optical (NLO) property] in alkaline earth metal inverse sandwich complexes, which have Mg or Ca atoms as an alkaline earth metal and a four‐ or eight‐membered ring as an organic ligand (4‐Mg, 4‐Ca, 8‐Mg, and 8‐Ca). Through detailed analysis of diradical character with the valence configuration interaction (VCI) model, we have found that the higher period metal leads to a larger metal–metal distance with larger y value 0.8–0.9, while a larger ring size of organic ligand leads to smaller diradical character values due to the larger transfer integral (smaller distance) between metals. These features are explained by orbital diagrams and VCI analysis. Indeed, it is found that 8‐Ca has the largest γ value, which is 4.94 times as large as that of the system with the smallest γ value (8‐Mg). From these results, we obtain a design guideline for efficient third‐order NLO systems based on alkaline earth metal inverse sandwich complexes: a combination of alkaline earth metal with a higher period number and larger organic antiaromatic (4nπ) ring tends to enhance the γ value due to the larger metal–metal distance with keeping an intermediate y value.
Synthesis of Bi‐ and Polyfunctional Isoxazoles from Amino Acid Derived Halogenoximes and Active Methylene Nitriles
Authors: Chalyk Bohdan A. , Hrebeniuk Kateryna V. , Gavrilenko Konstantin S. , Shablykin Oleh V. , Yanshyna Oksana O. , Bash Daniil , Mykhailiuk Pavel K. , Liashuk Oleksandr S. , Grygorenko Oleksandr O.
Published: March 2018

The reaction of chloroximes that have a protected amino group and active methylene nitriles under basic conditions has been shown to give functionalized 5‐aminoisoxazoles in yields of 37–81 %. This method has a broad substrate scope, including nitriles that contain either an electron‐withdrawing (i.e., CO2Me, CN, or SO2Me) or a heteroaryl group at the α‐position. Moreover, a malononitrile dimer was employed in analogous transformations, which led to the formation of polyfunctional isoxazolo[5,4‐b]pyridines. The selective removal of the protecting groups contained in the product demonstrated the utility of these compounds as advanced building blocks in early drug discovery programs.
Convenient Palladium‐Catalyzed Reductive Carbonylation of Aryl Bromides Under Gas‐Free Conditions
Authors: Ying Jun , Fu Lu‐Yang , Zhou Chao , Qi Xinxin , Peng Jin‐Bao , Wu Xiao‐Feng
Published: March 2018

A convenient and efficient palladium‐catalyzed reductive carbonylation of aryl and heteroaryl bromides has been developed. With formic acid as the CO source and sodium formate or formic acid as the hydrogen donor, various aromatic and heteroaromatic aldehydes were produced in good to excellent yields (53–94 %) under gas‐free conditions.
Connected guys: Endorsement of masculine honour predicts more frequent contact with members of criminal organisations
Authors: Travaglino Giovanni A. , Drury Lisbeth
Published: March 2018

Italian criminal organisations (COs) engage in contact with community members to assert their control over local populations in Southern Italy. According to intracultural appropriation theory,COs’ presence in these regions is legitimised by values of masculinity and honour. Here, we test the role of these values in drawing people closer toCOs, facilitating more frequent contact withCOs’ members. Study 1 (NT1 = 176,NT2 = 170) used a two‐wave longitudinal design demonstrating that endorsement of masculine honour predicts more frequent contact withCOs after five months. In contrast, results revealed no longitudinal effect of contact frequency on masculine honour endorsement. Using a cross‐sectional design, Study 2 (N = 314) extended these results by revealing an indirect effect of masculine honour on the tendency to seeCOs as embodying honour and respect (romanticisation), through more frequent contact withCOs’ members. Limitations, directions for future research and implications of these results are discussed.
A direct replication: Unconscious arithmetic processing
Authors: Karpinski Andrew , Briggs Jessie C. , Yale Miriam
Published: March 2018

Across two experiments involving four presentation times in total, Sklar et al. (Proceedings of the National Academy of Sciences of the United States of America, 109, 2012, 19614) found that complex subtraction equations can be solved without awareness of the equations. These findings challenge the current position that consciousness is necessary for performing abstract, rule‐following tasks. Given the important implications of their work, we aimed to directly replicate Sklar's findings using a larger sample (n = 94) from a different population. Using continuous flash suppression, we investigated if people were able to solve an equation after subliminal (1,300 ms) exposure to it. We found evidence of unconscious subtraction consistent with Sklar et al., albeit the effect is weak. Critical review of our results and implications for further research are discussed.
Fabrication of β‐Cyclodextrin/Glycine/Carbon Nanotubes Electrochemical Neurotransmitters Sensor – Application in Ultra‐sensitive Determination of DOPAC in Human Serum
Authors: Galal Ahmed , Atta Nada F. , El‐Ads Ekram H. , El‐Gohary Asmaa R. M.
Published: March 2018

In this work, an electrochemical sensor was constructed by applying two successive thin layers of glycine‐carbon nanotubes mixture and β‐cyclodextrin (CNTs‐Gly)/CD over glassy carbon electrode surface for some neurotransmitters determination. A host‐guest interaction between CD and neurotransmitters molecules is expected and resulted in enhanced sensitivity, selectivity and stability of sensor response. Other components of the sensor are crucial for the unique electrochemical response. Carbon nanotubes allowed large surface area for glycine distribution that provided hydrogen bonding to CD moieties and contributed to facilitated charge transfer. It was possible to determine 3,4‐dihydroxy phenyl acetic acid (DOPAC) in the linear range of 0.1 μmol L−1 to 80 μmol L−1 with detection limit of 9.40 nmol L−1, quantification limit of 31.5 nmol L−1 and sensitivity of 4.16 μA/μmol L−1. The proposed sensor was applied in synthetic cerebrospinal fluids samples using random standard addition method. Also, the proposed sensor was used to determine DOPAC in presence of common interferences and acceptable recovery results were achieved for its analysis in real blood serum. Figures of merit for (CNTs‐Gly)/CD composite in terms of precision, robustness, repeatability and reproducibility were reported.
Quality by design‐assisted development of a capillary electrophoresis method for the chiral purity determination of dexmedetomidine
Authors: Krait Sulaiman , Scriba Gerhard K. E.
Published: March 2018

Dexmedetomidine is a selective α2‐adrenergic agonist used for patient sedation, while its enantiomer levomedetomidine has no sedative effects. As CE has been shown to be a powerful technique for enantiomer analysis, the aim of the study was the quality by design‐based development of a CE‐based limit test for the enantiomeric impurity levomedetomidine. The analytical target profile was defined that the method should be able to determine levomedetomidine with acceptable precision and accuracy at the 0.1% level. From initial scouting experiments, sulfated β‐cyclodextrin was selected as chiral selector. The critical process parameters were identified in a fractional factorial resolution V+ design, while a central composite face centered design and Monte Carlo simulations were used for defining the design space of the method. The selected working conditions were a 21.3/31.5 cm, 50 μm id fused‐silica capillary, a 50 mM sodium phosphate buffer, pH 6.5, containing 40 mg/mL sulfated β‐cyclodextrin, a capillary temperature of 17°C and an applied voltage of 10 kV. Validation according to the ICH guideline Q2(R1) demonstrated repeatability and intermediate precision of content and migration time between 9.3 and 4.2% with accuracy in the range of 92.0 and 98.9%.
Gene expression profiling in healthy newborns from diverse localities of the Czech Republic
Authors: Honkova Katerina , Rossnerova Andrea , Pavlikova Jitka , Svecova Vlasta , Klema Jiri , Topinka Jan , Milcova Alena , Libalova Helena , Choi Hyunok , Veleminsky Milos , Sram Radim J. , Rossner Pavel
Published: March 2018

Prenatal exposure to air pollution is associated with intrauterine growth restriction and low birth weight. Gene expression changes in newborns in relation to air pollution have not been sufficiently studied. We analyzed whole genome expression in cord blood leukocytes of 202 newborns from diverse localities of the Czech Republic, differing among other factors in levels of air pollution: the district of Karvina (characterized by higher concentration of air pollutants) and Ceske Budejovice (lower air pollution levels). We aimed to identify differentially expressed genes (DEGs) and pathways in relation to locality and concentration of air pollutants. We applied the linear model to identify the specific DEGs and the correlation analysis, to investigate the relationship between the concentrations of air pollutants and gene expression data. An analysis of biochemical pathways and gene set enrichment was also performed. In general, we observed modest changes of gene expression, mostly attributed to the effect of the locality. The highest number of DEGs was found in samples from the district of Karvina. A pathway analysis revealed a deregulation of processes associated with cell growth, apoptosis or cellular homeostasis, immune response‐related processes or oxidative stress response. The association between concentrations of air pollutants and gene expression changes was weak, particularly for samples collected in Karvina. In summary, as we did not find a direct effect of exposure to air pollutants, we assume that the general differences in the environment, rather than actual concentrations of individual pollutants, represent a key factor affecting gene expression changes at delivery. Environ. Mol. Mutagen. 59:401–415, 2018. © 2018 Wiley Periodicals, Inc.