bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of solvent effect on the conductivity of 2‐mercaptopyridine‐doped solid polymer blend electrolytes and its application in dye‐sensitized solar cells
Authors: Theerthagiri Jayaraman , Senthil Raja Arumugam , Ali@Buraidah Mohd Hamdi , Madhavan Jagannathan , Mohd Arof Abdul Kariem 
Published: June 2015

ABSTRACTSolvents and electrolytes play an important role in the fabrication of dye‐sensitized solar cells (DSSCs). We have studied the poly(ethylene oxide)‐poly(methyl methacrylate)‐KI‐I2 (PEO‐PMMA‐KI‐I2) polymer blend electrolytes prepared with different wt % of the 2‐mercaptopyridine by solution casting method. The polymer electrolyte films were characterized by the FTIR, X‐ray diffraction, electrochemical impedance and dielectric studies. FTIR spectra revealed complex formation between the PEO‐PMMA‐KI‐I2 and 2‐mercaptopyrindine. Ionic conductivity data revealed that 30% 2‐mercaptopyridine‐doped PEO‐PMMA‐KI‐I2 electrolyte can show higher conductivity (1.55 × 10−5 S cm−1) than the other compositions (20, 40, and 50%). The effect of solvent on the conductivity and dielectric of solid polymer electrolytes was studied for the best composition (30% 2‐mercaptopyridine‐doped PEO‐PMMA‐KI‐I2) electrolyte using various organic solvents such as acetonitrile, N,N‐dimethylformamide, 2‐butanone, chlorobenzene, dimethylsulfoxide, and isopropanol. We found that ac‐conductivity and dielectric constant are higher for the polymer electrolytes processed from N,N‐dimethylformamide. This observation revealed that the conductivity of the solid polymer electrolytes is dependent on the solvent used for processing and the dielectric constant of the film. The photo‐conversion efficiency of dye‐sensitized solar cells fabricated using the optimized polymer electrolytes was 3.0% under an illumination of 100 mW cm−2. The study suggests that N,N‐dimethylformamide is a good solvent for the polymer electrolyte processing due to higher ac‐conductivity beneficial for the electrochemical device applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42489.
PPS/recycled PEEK/ carbon nanotube composites: Structure, properties and compatibility
Authors: Deng Shuling , Lin Zhidan , Cao Lin , Xian Jiaming , Liu Chunyuan 
Published: June 2015

ABSTRACTBlends of poly(phenylene sulfide) (PPS) and recycled poly(ether ether ketone) (r‐PEEK) were prepared using a twin‐screw extruder. The carbon nanotube (CNT) added to the blends not only improved the compatibility of the two polymers, but also affected the morphology of the immiscible PPS/r‐PEEK blends. R‐PEEK always forms the dispersed phase and PPS the continuous phase in such blends. In the composite, CNT particles were observed in the PPS phase, mostly distributes in the interface between PPS and PEEK. The results show that r‐PEEK improves the impact and tensile strength of PPS, but does not provide nucleation effect on PPS. However, CNT improved the flexural modulus of PPS/r‐PEEK blends and promoted the crystallization of r‐PEEK rather than that of PPS. The prepared PPS/r‐PEEK blends provided larger electrical conductivity than neat polymers. Adding 20 wt % CNT to blend resulted in composite with the minimum volume resistivity, a reduction of four orders of magnitude, compared with that of the neat blend. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42497.
Towards meso‐Ester BODIPYs with Aggregation‐Induced Emission Properties: The Effect of Substitution Positions
Authors: Chua Ming Hui , Ni Yong , Garai Monalisa , Zheng Bin , Huang Kuo‐Wei , Xu Qing‐Hua , Xu Jianwei , Wu Jishan 
Published: June 2015

AbstractThree meso‐ester boron dipyrromethene (BODIPY) dyes have been synthesized and functionalized with aggregation‐induced emission (AIE)‐active tetraphenylethene or triphenylethene moieties. It was found that functionalizing at the different positions of the BODIPY core resulted in the final dye having different emission properties in response to aggregation: from aggregation‐induced quenching (ACQ) to being AIE active. X‐ray crystallographic analysis was thus performed to provide an explanation for these differences.
Realization of FTA with High Tracking Accuracy in FSO
Authors: Lv Chun Lei , Li Yan , Zhang Yun Feng , Jiang Hui Lin , Tong Shou Feng 
Published: June 2015

AbstractHigh tracking accuracy is a prerequisite of reliable space optical communication links and its effective means is the utilization of coarse and fine compound‐axis structure. After an in‐depth study of the active laser tracking mechanism of fine tracking assembly, this paper emphasizes the exploration of these methods enabling the improvement of tracking accuracy under the condition of relative movement and platform vibration. Firstly, switching technique using a single beacon between different divergence angles is put forward to improve the signal to noise ratio (SNR) of the focal spot. Secondly, the high‐frame rate charge‐coupled device is achieved after proposing the pseudo random window readout technique. Thirdly, the unique design of the high resonant frequency of two‐dimensional PZT fast steering mirror (FSM) and sub‐pixel subdivision technique with adaptive control of integral time is used to achieve high accuracy and fast beam pointing. Fourthly, this paper puts forward a digital servol control method with intelligent variable structure. Finally, after building a hardware‐in‐loop simulation platform, the tracking accuracy of 3μrad is concluded according to simulation experimental results.
Synthetic vectors for gene delivery: An overview of their evolution depending on routes of administration.
Authors: Belmadi Nawal , Midoux Patrick , Loyer Pascal , Passirani Catherine , Pichon Chantal , Le Gall Tony , Jaffres Paul‐Alain , Lehn Pierre , Montier Tristan 
Published: June 2015

AbstractNucleic acid delivery constitutes an emerging therapeutic strategy to cure various human pathologies. This therapy consists of introducing genetic material into the whole body or isolated cells to correct a cellular abnormality or disfunction. As with any drug, the main objective of nucleic acid delivery is to establish optimal balance between efficacy and tolerance. The methods of administration and the vectors used are selected depending on whether the goal of treatment is the production of an active protein; the replacement of a missing or inactive gene; or the combat of acquired diseases, such as cancer or AIDS. In that sense, synthetic vectors represent a valuable solution because they are well characterized, their structure can be fine tuned, and their potential toxicity can be reduced, since toxicity depends on the composition of the formulations. Here we review various synthetic vectors for gene delivery and address the question of their biodistribution as a function of the route of administration. We highlight the modifications to vectors structure and formulations necessary to overcome the major hurdles limiting the effectiveness of nucleic acid therapies.
Meta-analysis of surgical outcome after enucleation versus standard resection for pancreatic neoplasms
Authors: Hüttner F J , Koessler-Ebs J , Hackert T , Ulrich A , Büchler M W , Diener M K 
Published: June 2015

Abstract

Background
Pancreatic enucleation is a tissue-sparing approach to pancreatic neoplasms and may result in better postoperative pancreatic function than standard pancreatic resection. The objective of this review was to compare the postoperative outcome after pancreatic enucleation versus standard resection.

Methods
MEDLINE, Embase and the Cochrane Library were searched systematically until February 2015 to identify studies comparing the outcome of enucleation versus standard resection for pancreatic neoplasms. After critical appraisal, meta-analysis was performed and the findings were presented as odds ratios or weighted mean differences with corresponding 95 per cent c.i.

Results
Twenty-two observational studies (1148 patients) were included. Duration of surgery (P &lt; 0·001), blood loss (P &lt; 0·001), length of hospital stay (P = 0·04), and postoperative endocrine (P &lt; 0·001) and exocrine (P = 0·01) insufficiency were lower after enucleation than after standard resection. Mortality (P = 0·44), overall complications (P = 0·74), reoperation rate (P = 0·93) and delayed gastric emptying (P = 0·15) were not significantly different between the two approaches. The overall rate of postoperative pancreatic fistula (POPF) was higher after enucleation than after standard resection (P &lt; 0·001). However, the raised POPF rate did not result in higher mortality or overall morbidity. Sensitivity analysis of high-volume studies (total of more than 20 enucleations and more than 4 per year) showed that, in specialized centres, enucleation can be performed with no increased risk of POPF (P = 0·12).

Conclusion
Compared with standard resection, pancreatic enucleation can be performed effectively and with comparable safety in high-volume institutions. Enucleation should be considered instead of standard resection for selected pancreatic neoplasms.
Adjuvant taxanes and the development of breast cancer-related arm lymphoedema
Authors: Cariati M , Bains S K , Grootendorst M R , Suyoi A , Peters A M , Mortimer P , Ellis P , Harries M , Van Hemelrijck M , Purushotham A D 
Published: June 2015

Abstract

Background
Despite affecting approximately one-quarter of all patients undergoing axillary lymph node dissection, the pathophysiology of breast cancer-related lymphoedema (BCRL) remains poorly understood. More extensive locoregional treatment and higher body mass index have long been identified as major risk factors. This study aimed to identify risk factors for BCRL with a specific focus on the potential impact of chemotherapy on the risk of BCRL.

Methods
This was a retrospective analysis of a cohort of consecutive patients with breast cancer treated at a major London regional teaching hospital between 1 January 2010 and 31 December 2012. All patients had node-positive disease and underwent axillary lymph node dissection. Data regarding tumour-, patient- and treatment-related characteristics were collected prospectively. The diagnosis of BCRL was based on both subjective and objective criteria. Multivariable Cox proportional hazards regression was used to assess the association between treatment and risk of BCRL.

Results
Some 27·1 per cent of all patients (74 of 273) developed BCRL over the study period. Administration of taxanes showed a strong association with the development of BCRL, as 52 (33·5 per cent) of 155 patients who received taxanes developed BCRL. Multivariable Cox regression analysis demonstrated that patients who received taxanes were nearly three times more likely to develop BCRL than patients who had no chemotherapy (hazard ratio 2·82, 95 per cent c.i. 1·31 to 6·06). No such increase was observed when taxanes were administered in the neoadjuvant setting.

Conclusion
The present findings suggest that adjuvant taxanes play a key role in the development of BCRL after surgery. This may support the use of taxanes in a neoadjuvant rather than adjuvant setting.
The ratio of oxidized and reduced forms of selected antioxidants as a possible marker of oxidative stress in humans
Authors: Kanďár Roman 
Published: June 2015

AbstractOxidative stress is an imbalance between reactive oxygen species exposure and the ability of organisms to detoxify the reactive intermediates and to repair the oxidative damage of biologically important molecules. Many clinical studies of oxidative stress unfortunately provide conflicting and contradictory results. The ability of antioxidant systems to adequately respond to oxidative stress can be used in laboratory diagnostics. In the present review, methods using the ratio of reduced and oxidized forms of uric acid, ascorbic acid, glutathione and coenzyme Q10as suitable indicators of oxidative stress are discussed. From the mentioned publications it is evident that suitable sample preparation prior to analysis is crucial. Copyright © 2015 John Wiley & Sons, Ltd.
Parallel manipulator software tool for design, analysis, and simulation of 195 GSP mechanisms
Authors: Toz Metin , Kucuk Serdar 
Published: June 2015

ABSTRACTIn this paper, a new parallel manipulator software tool based on the MATLAB Graphical User Interface (GUI) is developed for design, analysis and simulation of 195 6‐DOF General Stewart Platform mechanisms (GSP). The new proposed tool called as GSPDAP uses four basic leg types (SPS, SPC, CPS, and CCC) to design GSP mechanisms. Point or line coordinates required for leg connections are sufficient for GSPDAP to design a GSP mechanism. Once the design of a GSP mechanism is completed, GSPDAP provides the user with several analyses such as inverse kinematics, Jacobian matrix, workspace, and dexterity. It is not necessary for the user to have preliminary knowledge to obtain the inverse kinematics or Jacobian matrix etc. Additionally, GSPDAP generates symbolic equations for the inverse kinematics and the inverse Jacobian matrices of 195 GSP mechanisms. Including 195 parallel manipulator in its library, GSPDAP provides the educational users to profoundly improve the understanding of parallel manipulator fundamentals through interactive simulation. Parallel manipulators are more complex structures than their serial counterparts. Therefore, designing even one parallel manipulator is very cumbersome and expensive issue. In this condition GSPDAP may provide educators and students to design their manipulators in a computer environment with minimum cost. © 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:931–946, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21665
Direct Synthesis of Phosphorus‐Doped Mesoporous Carbon Materials for Efficient Electrocatalytic Oxygen Reduction
Authors: Zhu Yun‐Pei , Liu Youlin , Liu Yu‐Ping , Ren Tie‐Zhen , Chen Tiehong , Yuan Zhong‐Yong 
Published: June 2015

AbstractChemical doping has been recognized as a promising route to achieve novel physicochemical functions of porous carbons as metal‐free catalysts in renewable energy‐related technologies, such as electrochemical oxygen reduction reaction (ORR). However, it remains challenging to exploit an effective method for the synthesis of metal‐free carbonaceous electrocatalysts. Herein, we report the direct synthesis of phosphorus‐doped mesoporous carbonaceous electrocatalysts for the first time through soft‐templating method, in which organophosphonic acid serves as the phosphorus source. The resulting mesoporous carbon material possesses high doping level, large surface area, and an interconnected mesopore system, ensuring the sufficient exposure and availability of catalytic sites to realize considerable catalytic activity for ORR in alkaline media. More importantly, much better tolerance for methanol oxidation, higher durability, and comparable Tafel slopes as compared with the commercial Pt/carbon (Pt/C) catalyst are valuable for developing alternative fuel cells and metal–air batteries.
Reactivity of Para‐Substituted Fluorobenzenes in Palladium‐catalyzed Intermolecular Direct Arylations
Authors: He Mian , Soulé Jean‐François , Doucet Henri 
Published: June 2015

AbstractThe influence of both electron‐withdrawing and electron‐donating substituents such as amino, bromo, chloro, ketone, methyl, methoxy, and nitro at C‐4 on fluorobenzene derivatives, for palladium‐catalyzed direct arylation at α‐position to the fluorine atom has been explored. With moderate electron‐withdrawing substituents, the reaction proceeds nicely using phosphine‐free PdCl2 catalyst, at a very low loading, and potassium pivalate/dimethylacetamide (PivOK/DMA) as catalytic system. In all cases, a regioselective arylation at the α position to the fluorine atom was observed. Moreover, a wide variety of substituents on the aryl bromide coupling partner, such as formyl, nitro, nitrile, chloro, and methyl, and also heteroaryl bromides was tolerated.
Shape and Size Control of LiFePO4 for High‐Performance Lithium‐Ion Batteries
Authors: Liang Yachun , Wen Kechun , Mao Yiwu , Liu Zhongping , Zhu Gaolong , Yang Fei , He Weidong 
Published: June 2015

AbstractOlivine‐type LiFePO4, which is an extensively employed cathode material in lithium‐ion batteries, has attracted much attention due to its abundance, low cost, low toxicity, and high thermal stability. However, low electronic conductivity and sluggish lithium‐ion diffusion in LiFePO4 result in poor rate capability, which seriously limits its applications in next‐generation green and sustainable power systems. Extensive efforts have focused on exploring efficient synthetic approaches to optimize its performance by controlling the particle size and shape. In this Review, we first summarize the typical synthetic methods for LiFePO4 and follow with a discussion of the correlation between LiFePO4 crystal size/morphology and the associated electrochemical performance. Our overview seeks to provide insightful guidance for the design of high‐performance lithium‐ion batteries with highly efficient and cost‐effective LiFePO4 cathode materials.
Structure Modification Function of g‐C3N4 for Al2O3 in the In Situ Hydrothermal Process for Enhanced Photocatalytic Activity
Authors: Li Fa‐tang , Liu Shao‐jia , Xue Ya‐bin , Wang Xiao‐jing , Hao Ying‐juan , Zhao Jun , Liu Rui‐hong , Zhao Dishun 
Published: June 2015

AbstractHeterojunctions of g‐C3N4/Al2O3 (g‐C3N4=graphitic carbon nitride) are constructed by an in situ one‐pot hydrothermal route based on the development of photoactive γ‐Al2O3 semiconductor with a mesoporous structure and a high surface area (188 m2g−1) acting as electron acceptor. A structure modification function of g‐C3N4 for Al2O3 in the hydrothermal process is found, which can be attributed to the coordination between unoccupied orbitals of the Al ions and lone‐pair electrons of the N atoms. The as‐synthesized heterojunctions exhibit much higher photocatalytic activity than pure g‐C3N4. The hydrogen generation rate and the reaction rate constant for the degradation of methyl orange over 50 % g‐C3N4/Al2O3 under visible‐light irradiation (λ>420 nm) are 2.5 and 7.3 times, respectively, higher than those over pristine g‐C3N4. The enhanced activity of the heterojunctions is attributed to their large specific surface areas, their close contact, and the high interfacial areas between the components as well as their excellent adsorption performance, and efficient charge transfer ability.
Iron/Brønsted Acid Catalyzed Asymmetric Hydrogenation: Mechanism and Selectivity‐Determining Interactions
Authors: Hopmann Kathrin H. 
Published: June 2015

AbstractHydrogenation catalysts involving abundant base metals such as cobalt or iron are promising alternatives to precious metal systems. Despite rapid progress in this field, base metal catalysts do not yet achieve the activity and selectivity levels of their precious metal counterparts. Rational improvement of base metal complexes is facilitated by detailed knowledge about their mechanisms and selectivity‐determining factors. The mechanism for asymmetric imine hydrogenation with Knölker’s iron complex in the presence of chiral phosphoric acids is here investigated computationally at the DFT‐D level of theory, with models of up to 160 atoms. The resting state of the system is found to be an adduct between the iron complex and the deprotonated acid. Rate‐limiting H2 splitting is followed by a stepwise hydrogenation mechanism, in which the phosphoric acid acts as the proton donor. CH⋅⋅⋅O interactions between the phosphoric acid and the substrate are involved in the stereocontrol at the final hydride transfer step. Computed enantiomeric ratios show excellent agreement with experimental values, indicating that DFT‐D is able to correctly capture the selectivity‐determining interactions of this system.
Size‐Dependent Enantioselective Adsorption of Racemic Molecules through Homochiral Metal–Organic Frameworks Embedding Helicity
Authors: Xu Zhong‐Xuan , Fu Hong‐Ru , Wu Xin , Kang Yao , Zhang Jian 
Published: June 2015

AbstractHomochiral metal–organic frameworks (HMOFs) are efficient materials for enantioselective adsorption. However, the combination of size selectivity and enantioselectivity is still a major challenge in the field of HMOFs. Herein, two enantiomorphic HMOFs built from predesigned proline‐derived ligands are presented. Both of them show multiple homochiral features: they contain four different helical chains and three types of helical channels. Due to the size effect of the helical channels, each HMOF can enantioselectively adsorb methyl lactate with high ee. The results reveal a new approach toward size‐dependent enantioselective separation of racemic compounds by using HMOFs built from inexpensive proline derivatives.
Combined Spectroscopic and Electrochemical Detection of a NiI⋅⋅⋅HN Bonding Interaction with Relevance to Electrocatalytic H2Production
Authors: Kochem Amélie , O'Hagan Molly , Wiedner Eric S. , van Gastel Maurice 
Published: June 2015

AbstractThe [Ni(PR2NR′2)2]2+family of complexes are exceptionally active catalysts for proton reduction to H2. In this manuscript, we explore the first protonation step of the proposed catalytic cycle by using a catalytically inactive NiIcomplex possessing a sterically demanding variation of the ligand. Due to the paramagnetic nature of the NiIoxidation state, the protonated NiIintermediate has been characterized through a combination of cyclic voltammetry, electron nuclear double resonance (ENDOR) spectroscopy, and hyperfine sublevel correlation (HYSCORE) spectroscopy. Both the electrochemical and spectroscopic studies indicate that the NiIcomplex is protonated at a pendant amine that isendoto Ni, which suggests the presence of an intramolecular NiI⋅⋅⋅HN bonding interaction. Using density functional theory, the hydrogen bond was found to involve three doubly‐occupied, localized molecular orbitals: the 3dxz, 3d, and 3dyzorbitals of nickel. These studies provide the first direct experimental evidence for this critical catalytic intermediate, and implications for catalytic H2production are discussed.
Chiral N,O‐Ligand/[Cu(OAc)2]‐Catalyzed Asymmetric Construction of 4‐Aminopyrrolidine Derivatives by 1,3‐Dipolar Cycloaddition of Azomethine Ylides with α‐Phthalimidoacrylates
Authors: Wang Zheng , Yu Xingxin , Tian Bo‐Xue , Payne Daniel T. , Yang Wu‐Lin , Liu Yang‐Zi , Fossey John S. , Deng Wei‐Ping 
Published: June 2015

AbstractA protocol to access useful 4‐aminopyrrolidine‐2,4‐dicarboxylate derivatives has been developed. A variety of chiral N,O‐ligands derived from 2,3‐dihydroimidazo[1,2‐a]pyridine motifs have been evaluated in the asymmetric 1,3‐dipolar cycloaddition of azomethine ylides to α‐phthalimidoacrylates. Reactions catalyzed by copper in combination with ligand 7‐Cl‐DHIPOH provided the highest level of stereoselectivity for the 1,3‐dipolar cycloaddition reaction. The reaction tolerates both β‐substituted and β‐unsubstituted α‐phthalimidoacrylate as dipolarophiles, affording the corresponding quaternary 4‐aminopyrrolidine cycloadducts with excellent diastereo‐ (>98:2 d.r.) and enantioselectivities (up to 97 % ee). Removal of the phthalimido protecting group can be accomplished by a simple NaBH4 reduction. Theoretical calculations employing DFT methods show this cycloaddition reaction is likely to proceed through a stepwise mechanism and the stereochemistry was also theoretically rationalized.
Alkylation of Amines with Alcohols and Amines by a Single Catalyst under Mild Conditions
Authors: Zou Qingzhu , Wang Chao , Smith Jen , Xue Dong , Xiao Jianliang 
Published: June 2015

AbstractAn efficient catalytic system for the alkylation of amines with either alcohols or amines under mild conditions has been developed, using cyclometallated iridium complexes as catalysts. The method has broad substrate scope, allowing for the synthesis of a diverse range of secondary and tertiary amines with good to excellent yields. By controlling the ratio of substrates, both mono‐ and bis‐alkylated amines can be obtained with high selectivity. In particular, methanol can be used as the alkylating reagent, affording N‐methylated products selectively. A strong solvent effect is observed for the reaction.