bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of chitosan–graphene nanosheet composites with enhanced electrochemical and mechanical properties
Authors: Wu Guangyu , Huang Jianguo , Li Weidong 
Published: March 2017

ABSTRACTIn this study, we proposed an alternative way to produce graphene nanosheet (GNS)/chitosan (CS) composites. Graphite‐intercalating compounds (GICs) were prepared by graphite and m‐chloroperbenzion acid (M‐CPBA) as starting materials. The GNS–CS composites were produced through the mixing of the GICs into CS and the removal of impurities in the final step. X‐ray diffraction, atomic force microscopy, and transmission and scanning electron microscopy analyses showed that graphite could be effectively exfoliated by an intercalating agent (M‐CPBA) and the GNSs were homogeneously dispersed into the CS matrix. Furthermore, we demonstrated that the electrochemical behavior and mechanical properties of the GNS–CS composites were significantly improved with a low level of GNSs in CS. The redox peak current increased 509%, and the modulus and hardness of the GNS–CS composites increased by 2.7 and 0.15 GPa, respectively, when the GNSs addition was 0.6 wt %. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45104.
Bio‐based flexible polyurethane foams derived from succinic polyol: Mechanical and acoustic performances
Authors: Oliviero Maria , Verdolotti Letizia , Stanzione Mariamelia , Lavorgna Marino , Iannace Salvatore , Tarello Maurizio , Sorrentino Andrea 
Published: March 2017

ABSTRACTPolyurethane foams have widespread applications as temperature insulators, sound barriers and shock absorbers. The market requests for these materials growth annually and its production pose serious environmental problems. In this article, several polyurethane foams compositions are obtained by partially replacing a conventional synthetic polyol with a new bio‐polyol made from succinic acid. The effects of water content, carbon black addition and bio‐succinic polyol replacement on foam properties are investigated. Results show that the addition of bio‐succinic polyol significantly changes the foam morphology leading to both an increase of the interconnectivity and an enhancement of mechanical properties. Furthermore, the addition of carbon black modifies the cell morphology and increases the foam density; consequently, an improvement in sound insulation performance at high frequency values is recorded. Due to this peculiar combination of mechanical and acoustic properties, the produced bio‐foams may be considered as potential substitutes of conventional flexible polyurethane foams to reduce vibrations, noise pollution, and consequently increase comfort in automobile and aircraft industries. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45113.
Intuitive Understanding of σ Delocalization in Loose and σ Localization in Tight Helical Conformations of an Oligosilane Chain
Authors: Jovanovic Milena , Antic Dean , Rooklin David , Bande Annika , Michl Josef 
Published: March 2017

AbstractConformational effects on the σ‐electron delocalization in oligosilanes are addressed by Hartree–Fock and time‐dependent density functional theory calculations (B3LYP, 6‐311G**) at MP2 optimized geometries of permethylated uniformly helical linear oligosilanes (all‐ω‐SinR2n+2) up to n=16 and for backbone dihedral angles ω=55–180°. The extent of σ delocalization is judged by the partition ratio of the highest occupied molecular orbital and is reflected in the dependence of its shape and energy and of UV absorption spectra on n. The results agree with known spectra of all‐transoid loose‐helix conformers (all‐[±165]‐SinMe2n+2) and reveal a transition at ω≈90° from the “σ‐delocalized” limit at ω=180° toward and close to the physically non‐realizable “σ‐localized” tight‐helix limit ω=0 with entirely different properties. The distinction is also obtained in the Hückel Ladder H and C models of σ delocalization. An easy intuitive way to understand the origin of the two contrasting limits is to first view the linear chain as two subchains with alternating primary and vicinal interactions (σ hyperconjugation), one consisting of the odd and the other of the even σ(SiSi) bonds, and then allow the two subchains to interact by geminal interactions (σ conjugation).
How positive and negative contact relate to attitudes towards Roma: Comparing majority and high‐status minority perspectives
Authors: Visintin Emilio Paolo , Green Eva G.T. , Pereira Adrienne , Miteva Polimira 
Published: March 2017

AbstractIntergroup contact scholars have recently called for analyzing the effects of negative intergroup contact. In response to this call, we examined the correlates of positive and negative contact with one of the most stigmatized ethnic minorities, that is, Roma. We conducted a study in Bulgaria considering the point of view of the ethnic Bulgarian majority (n = 516) and of Bulgarian Turks (n = 274), an ethnic minority with higher status compared to Roma. Regression analyses showed that positive contact was associated with reduced prejudice and more support for pro‐Roma policies, while negative contact revealed the opposite pattern. These associations did not differ between ethnic Bulgarians and Bulgarian Turks. Moreover, positive and negative intergroup emotions mediated the relationships between positive and negative contact on the one hand and prejudice and policy support on the other. Our study highlights the importance of emotional processes involved in positive and negative intergroup contact experiences and encourages future research to analyze how absolute versus relative status differences shape the effects of positive and negative contact in complex hierarchical societies.
Tuning Hole and Electron Transfer from Photoexcited CdSe Quantum Dots to Phenol Derivatives: Effect of Electron‐Donating and ‐Withdrawing Moieties
Authors: Debnath Tushar , Sebastian Deepa , Maiti Sourav , Ghosh Hirendra N. 
Published: March 2017

AbstractCharge‐transfer processes from photoexcited CdSe quantum dots (QDs) to phenol derivatives with electron‐ donating (4‐methoxy) and ‐withdrawing (4‐nitro) moieties have been demonstrated by using steady‐state and time‐ resolved emission and femtosecond transient absorption spectroscopy. Steady‐state and time‐resolved emission studies suggest that in the presence of both 4‐nitrophenol (4NP) and 4‐methoxyphenol (4MP) CdSe QDs luminescence is quenched. Stern–Volmer analysis suggests both static and dynamic mechanisms are active for both the QD/phenol composites. Cyclic voltammetric analysis recommends that photoexcited CdSe QDs can donate electrons to 4NP and holes to 4MP. To reconfirm both electron‐ and hole‐transfer mechanisms, CdSe/CdS quasi‐type II and CdSe/CdTe type II core–shell nanocrystals were synthesized and photoluminescence quenching was monitored in the absence and presence of both 4NP and 4MP, for which hole and electron transfer were systematically restricted. Results suggest that indeed electron and hole transfer take place from photoexcited CdSe to 4NP and 4MP, respectively. To monitor the charge‐transfer dynamics in both systems on an early timescale, femtosecond transient absorption spectroscopic techniques have been employed. Electron and hole transfer and charge‐recombination dynamics are discussed and the effect of electron‐donating and ‐withdrawing groups has been demonstrated.
Multimetallic and Mixed Environment Iridium(III) Complexes: A Modular Approach to Luminescence Tuning Using a Host Platform
Authors: Pritchard Victoria E. , Rota Martir Diego , Zysman‐Colman Eli , Hardie Michaele J. 
Published: March 2017

AbstractMononuclear and trinuclear bis‐cyclometallated IrIII complexes of the host ligands tris(4‐[4′‐methyl‐2,2′‐bipyridyl]methyl)cyclotriguaiacylene (L1) and tris(4‐(4′‐methyl‐2,2′‐ bipyridyl)carboxy)cyclotriguaiacylene (L2) have been prepared. Complexes [{Ir(ppy)2}3(L1)](PF6)3 (1.1), [{Ir(ppy)2}(L1)](PF6)3 (1.2), [{Ir(ppy)2}3(L2)](PF6)3 (2.1) and [{Ir(ppy)2}(L2)](PF6)3 (2.2) (where ppy=phenylpyridinato) showed distinct photophysical properties depending on the L ligand. Complexes featuring the L1 ligand were comparatively blue‐shifted in solution, with longer lifetimes and higher quantum yields. The mixed bis‐cyclometallated IrIII complexes [{Ir(ppy)2}{Ir(dFppy)2}2(L1)](PF6)3 (1.3), [{Ir(ppy)2}{Ir(dFppy)2}2(L2)](PF6)3 (2.3), [{Ir(ppy)2}2{Ir(dFppy)2}(L1)](PF6)3 (1.4) and [{Ir(ppy)2}2{Ir(dFppy)2}(L2)](PF6)3 (2.4) (where dFppy=2,4‐difluorophenylpyrinato) were also synthesised. Steady‐state and time‐resolved spectroscopy, along with electrochemical investigations, show that the Ir(III) chromophores within these mixed Ir‐environment species behave as isolated centres, with no energy transfer or electronic communication between them.
A Simple Tetraminocalix[4]arene as a Highly Efficient Catalyst under “On‐Water” Conditions through Hydrophobic Amplification of Weak Hydrogen Bonds
Authors: De Rosa Margherita , La Manna Pellegrino , Soriente Annunziata , Gaeta Carmine , Talotta Carmen , Hickey Neal , Geremia Silvano , Neri Placido 
Published: March 2017

AbstractThe simple tetraminocalix[4]arene 1, which contains weak H‐bond‐donor NH2 groups, is reported to be a highly efficient organocatalyst for the Vinylogous Mukaiyama Aldol Reaction (VMAR) of 2‐(trimethylsilyloxy)furan 5 with α‐ketoesters 6 a–l under “on‐water” conditions owing to the hydrophobic amplification of weak H‐bond interactions. The catalytic efficiency of calixarene catalyst 1 was shown to be closely related to its recognition abilities towards the reactants 5 and 6 through a multipoint recognition model. The proposed model provided good explanations for the differences on the reaction rate acceleration and on the stereoselectivity observed with different substrates.
An Untrodden Path: Versatile Fabrication of Self‐Supporting Polymer‐Stabilized Percolation Membranes (PSPMs) for Gas Separation
Authors: Friebe Sebastian , Mundstock Alexander , Schneider Daniel , Caro Jürgen 
Published: March 2017

AbstractThe preparation and scalability of zeolite or metal organic framework (MOF) membranes remains a major challenge, and thus prevents the application of these materials in large‐scale gas separation. Additionally, several zeolite or MOF materials are quite difficult or nearly impossible to grow as defect‐free layers, and require expensive macroporous ceramic or polymer supports. Here, we present new self‐supporting zeolite and MOF composite membranes, called Polymer‐Stabilized Percolation Membranes (PSPMs), consisting of a pressed gas selective percolation network (in our case ZIF‐8, NaX and MIL‐140) and a gas‐impermeable infiltrated epoxy resin for cohesion. We demonstrate the performance of these PSPMs by separating binary mixtures of H2/CO2 and H2/CH4. We report the brickwork‐like architecture featuring selective percolation pathways and the polymer as a stabilizer, compare the mechanical stability of said membranes with competing materials, and give an outlook on how economic these membranes may become.
Direct Noncovalent Activation of α,β‐Unsaturated Aldehydes for the Stereodivergent Synthesis of Substituted Cyclohexenes
Authors: Xie Ji‐Kang , Wang Yang , Lin Jun‐Bing , Ren Xiao‐Rui , Xu Peng‐Fei 
Published: March 2017

AbstractHOMO‐raising noncovalent activation of α‐aryl α,β‐unsaturated aldehydes using a bifunctional Brønsted base catalyst is achieved. The catalytically generated dienolate intermediate undergoes all‐carbon [4+2] cyclizations with nitroolefins, leading to chiral cyclohexenes with four contiguous stereocenters in high yields and with excellent enantioseletivity. Furthermore, the diastereodivergent synthesis of the products is realized by introducing a second steric control to the bifunctional catalyst; 4 isomers out of 16 possible stereoisomers of the products were selectively produced by simple use of two catalysts and their (pseudo)enantiomers. The results presented here provide new insights into the remote activation of the carbonyl functionality as well as the stereodivergent synthesis of complex chiral molecules with multiple stereocenters.
Edge Engineering of MoS2 Nanoribbons as High Performance Electrode Material for Na‐ion Battery: A First‐Principle Study
Authors: Wang Jianbin , Zhao Qing , Chen Jun 
Published: March 2017

AbstractSubstantial effort has been made to search for electrode materials of Na‐ion batteries with high energy/power density. The application of S‐saturated zigzag MoS2 nanoribbons (MoS2NRs) for Na‐ion batteries has been explored through density function theory (DFT). The theoretical maximum specific capacity reaches 386.4 mAh•g−1 via double‐side and special edge adsorption mode. The electronic structure reveals that there exists charge transfer between Na and MoS2NRs. The diffusion barrier on MoS2NRs (0.17 eV) is much lower than that of bulk MoS2 (1.15 eV), indicating an excellent diffusion kinetics. In addition, the S‐edge in MoS2NRs plays a key role. Firstly, the Mo edge was half saturated by S, which helps to stabilize the MoS2NRs as well as offer more intercalation sites for Na. On the other hand, Na migrates much faster on the S edge route in MoS2NRs. Our computational results show that S‐saturated MoS2NRs exhibit a great potential as electrode materials for Na‐ion batteries with high performance.
Construction of Redox Responsive Vesicles Based on a Supra‐Amphiphile for Enzyme Confinement
Authors: Pan Tiezheng , Zou Huixin , Sun Hongcheng , Liu Yao , Liu Shengda , Luo Quan , Dong Zeyuan , Xu Jiayun , Liu Junqiu 
Published: March 2017

AbstractRedox responsive vesicles were constructed based on self‐assembly of a supra‐amphiphile built by the host‐ guest interaction between β‐cyclodextrin and a ferrocene derivative. The structure and destruction‐reconstruction reversibility of the “smart” vesicles were clearly characterized by electron microscopy and dynamic light scattering. Notably, these vesicles were proved to be capable of controlled release function and bringing protease resistance to the enzyme, showing great biocompatibility and promising applications.
Clinical features of Bim deletion polymorphism and its relation with crizotinib primary resistance in Chinese patients with ALK/ROS1 fusion‐positive non–small cell lung cancer
Authors: Zhang Limin , Jiang Tao , Li Xuefei , Wang Yan , Zhao Chao , Zhao Sha , Xi Lei , Zhang Shijia , Liu Xiaozhen , Jia Yijun , Yang Hui , Shi Jinpeng , Su Chunxia , Ren Shengxiang , Zhou Caicun 
Published: March 2017

BACKGROUNDThe authors' previous study demonstrated that the B‐cell chronic lymphocytic leukemia/lymphoma (Bcl‐2)‐like 11 (BCL2L11) (Bim) deletion polymorphism was associated with poor clinical response to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in patients with non–small cell lung cancer (NSCLC) with EGFR mutations. The objective of the current study was to investigate the impact of the Bim deletion polymorphism among patients with anaplastic lymphoma kinase (ALK)‐positive or ROS proto‐oncogene 1, receptor tyrosine kinase (ROS1)‐positive NSCLC who were treated with crizotinib.METHODSA total of 55 patients with ALK‐positive NSCLC and 14 patients with ROS1‐positive NSCLC who were treated with crizotinib were enrolled into the current study. The Bim deletion polymorphism was analyzed by polymerase chain reaction. The clinical features of the Bim deletion polymorphism and its impact on the effect of crizotinib were investigated.RESULTSThe Bim deletion polymorphism was present in 9 of 69 patients with ALK‐positive or ROS1‐positive NSCLC (13.0%). There were no differences noted with regard to clinicopathological features between patients with and without the Bim deletion polymorphism. Patients with the Bim deletion polymorphism had a significantly shorter progression‐free survival (PFS) and lower objective response rate compared with those without (median PFS, 182 days vs 377 days [P = .008]) (objective response rate, 44.4% vs 81.7% [P =.041]) in all populations. The significant difference in PFS was observed in patients with ALK‐positive NSCLC (83 days vs 305 days [P =.0304]) compared with those with ROS1‐positive NSCLC (218 days vs not reached [P =.082]). Multivariate analysis indicated that the Bim deletion polymorphism was an independent predictive factor for patients with ALK‐positive NSCLC who were treated with crizotinib (hazard ratio, 4.786 [P =.006]).CONCLUSIONSThe Bim deletion polymorphism was found to be associated with poor clinical response to crizotinib in patients with ALK fusion‐positive NSCLC. Cancer 2017;123:2927–35. © 2017 American Cancer Society.
Management of stage III colon cancer in the elderly: Practice patterns and outcomes in the general population
Authors: Merchant Shaila J. , Nanji Sulaiman , Brennan Kelly , Karim Safiya , Patel Sunil V. , Biagi James J. , Booth Christopher M. 
Published: March 2017

BACKGROUNDClinical trials have established surgical resection and adjuvant chemotherapy (ACT) as the standard management for stage III colon cancer; however, the extent to which these results apply to elderly patients in routine practice is unclear. This article describes the management and outcomes of elderly patients with stage III colon cancer.METHODSAll cases of surgically resected colon cancer from 2002 to 2008 were identified with the population‐based Ontario Cancer Registry. Pathology reports were obtained for a random sample (25% of all cases); those with stage III disease constituted the study population. The utilization of ACT, cancer‐specific survival (CSS), and overall survival (OS) in elderly patients (≥70 years) and nonelderly patients (<70 years) were compared.RESULTSThe study population included 2920 patients, and 1521 (52%) were elderly. The 30‐ and 90‐day mortality rates increased with advanced age: <70 years, 2% and 5%; 70 to 74 years, 3% and 7%; 75 to 79 years, 5% and 8%, and ≥80 years, 9% and 16% (P < .001). ACT was delivered to 48% of elderly patients and to 81% of younger patients (P < .001). Factors independently associated with ACT utilization among the elderly were a younger age (P < .001), male sex (P = .041), and no comorbidities (P = .001). Among elderly patients, ACT was associated with improved CSS (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.60‐0.88) and OS (HR, 0.71; 95% CI, 0.60‐0.83); however, the magnitude of the benefit was smaller for elderly patients than younger patients (HR for CSS, 0.53; 95% CI, 0.42‐0.67; HR for OS 0.56; 95% CI, 0.45‐0.69).CONCLUSIONSHalf of elderly patients with stage III colon cancer do not receive ACT. Although the effect size is smaller than that in younger patients, ACT is associated with improved long‐term survival. Cancer 2017;123:2840–49. © 2017 American Cancer Society.
7‐year follow‐up after stereotactic ablative radiotherapy for patients with stage I non–small cell lung cancer: Results of a phase 2 clinical trial
Authors: Sun Bing , Brooks Eric D. , Komaki Ritsuko U. , Liao Zhongxing , Jeter Melenda D. , McAleer Mary F. , Allen Pamela K. , Balter Peter A. , Welsh James D. , O'Reilly Michael S , Gomez Daniel , Hahn Stephen M. , Roth Jack A. , Mehran Reza J. , Heymach John V. , Chang Joe Y. 
Published: March 2017

BACKGROUNDThe authors evaluated the efficacy, patterns of failure, and toxicity of stereotactic ablative radiotherapy (SABR) for patients with medically inoperable, clinical stage I non–small cell lung cancer (NSCLC) in a prospective clinical trial with 7 years of follow‐up. Clinical staging was performed according to the seventh edition of the American Joint Committee on Cancer TNM staging system.METHODSEligible patients with histologically confirmed NSCLC of clinical stage I as determined using positron emission tomography staging were treated with SABR (50 grays in 4 fractions). The primary endpoint was progression‐free survival. Patients were followed with computed tomography and/or positron emission tomography/computed tomography every 3 months for the first 2 years, every 6 months for the next 3 years, and then annually thereafter.RESULTSA total of 65 patients were eligible for analysis. The median age of the patients was 71 years, and the median follow‐up was 7.2 years. A total of 18 patients (27.7%) developed disease recurrence at a median of 14.5 months (range, 4.3‐71.5 months) after SABR. Estimated incidences of local, regional, and distant disease recurrence using competing risk analysis were 8.1%, 10.9%, and 11.0%, respectively, at 5 years and 8.1%, 13.6%, and 13.8%, respectively, at 7 years. A second primary lung carcinoma developed in 12 patients (18.5%) at a median of 35 months (range, 5‐67 months) after SABR. Estimated 5‐year and 7‐year progression‐free survival rates were 49.5% and 38.2%, respectively; the corresponding overall survival rates were 55.7% and 47.5%, respectively. Three patients (4.6%) experienced grade 3 treatment‐related adverse events. No patients developed grade 4 or 5 adverse events (toxicity was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 3.0]).CONCLUSIONSWith long‐term follow‐up, the results of the current prospective study demonstrated outstanding local control and low toxicity after SABR in patients with clinical stage I NSCLC. Regional disease recurrence and distant metastases were the dominant manifestations of failure. Surveillance for second primary lung carcinoma is recommended. Cancer 2017;123:3031–39. © 2017 American Cancer Society.
Are Various σ‐Hole Bonds Steered by the Same Mechanisms?
Authors: Grabowski Sławomir J. , Sokalski W. Andrzej 
Published: March 2017

AbstractRepresentative Lewis acid–Lewis base complexes linked by tetrel, pnicogen, chalcogen, and halogen bonds have been studied within the quantum theory of atoms in molecules (QTAIM) approach and the hybrid variation‐perturbation theory (HVPT) to analyze possible relationships between these σ‐hole dimers. Results obtained at the MP2/aug‐cc‐pVTZ level indicate numerous correlations similar to hydrogen‐bonded systems.
Predicting the pain continuum after adolescent idiopathic scoliosis surgery: A prospective cohort study
Authors: Chidambaran V. , Ding L. , Moore D.L. , Spruance K. , Cudilo E.M. , Pilipenko V. , Hossain M. , Sturm P. , Kashikar‐Zuck S. , Martin L.J. , Sadhasivam S. 
Published: March 2017

AbstractBackgroundChronic postsurgical pain (CPSP) affects half a million children annually in the United States, with dire socioeconomic consequences, including long‐term disability into adulthood. The few studies of CPSP in children are limited by sample size, follow‐up duration, non‐homogeneity of surgical procedure and factors evaluated.MethodsIn a prospective study of 144 adolescents undergoing a single major surgery (spine fusion), we evaluated demographic, perioperative, surgical and psychosocial factors as predictors of a continuum of postsurgical pain: immediate, pain maintenance at 2–3 months (chronic pain/CP) and persistence of pain a year (persistent pain/PP) after surgery.ResultsWe found an incidence of 37.8% and 41.8% for CP and PP. CP and acute pain were both significant predictors for developing PP (p‐value <0.001 and 0.003). Preoperative pain and higher postoperative opioid requirement was significantly associated with CP (p = 0.015, p = 0.002), while Childhood Anxiety Sensitivity Index (p = 0.002) and surgical duration (p = 0.014) predicted PP. The final regression models had reasonable predictive accuracy (c‐statistic of 0.73 and 0.83 for CP and PP, respectively). Anxiety scores and catastrophizing for child and parent were found to be significantly correlated (p = 0.005, p = 0.013 respectively). Pain trajectories revealed that 65% of patients who developed PP reported CP and high pain trends; however, 33% of those who developed PP could not be identified using solely pain criteria.ConclusionPersistent postsurgical pain in children is a significant problem. It can be predicted in part by combinations of psychological and clinical variables, which may provide evidence‐based measures to prevent development of CPSP in the future.SignificanceIn a homogeneous cohort of adolescents undergoing spine fusion, we report a high incidence of persistent postsurgical pain (41.8%) predicted by child anxiety, perioperative pain, and surgical duration. Our results stress timely preventive and therapeutic strategies.