bluuebunny/crossref_metadata_2025 huggingface dataset:
Porosity‐Controlled TiNb2O7 Microspheres with Partial Nitridation as A Practical Negative Electrode for High‐Power Lithium‐Ion Batteries
Authors: Park Hyunjung , Wu Hao Bin , Song Taeseup , (David) Lou Xiong Wen , Paik Ungyu
Published: January 2015

Titanium niobium oxide (TiNb2O7) has been recognized as a promising anode material for lithium‐ion batteries (LIBs) in view of its potential to operate at high rates with improved safety and high theoretical capacity of 387 mAh g−1. However, it suffers from poor Li+ ion diffusivity and low electronic conductivity originated from its wide band gap energy (Eg > 2 eV). Here, porous TiNb2O7 microspheres (PTNO MSs) are prepared via a facile solvothermal reaction. PTNO MSs have a particle size of ≈1.2 μm and controllable pore sizes in the range of 5–35 nm. Ammonia gas nitridation treatment is conducted on PTNO MSs to introduce conducting Ti1−xNbxN layer on the surface and form nitridated PTNO (NPTNO) MSs. The porous structure and conducting Ti1−xNbxN layer enhance the transport kinetics associated with Li+ ions and electrons, which leads to significant improvement in electrochemical performance. As a result, the NPTNO electrode shows a high discharge capacity of ≈265 mAh g−1, remarkable rate capability (≈143 mAh g−1 at 100 C) and durable long‐term cyclability (≈91% capacity retention over 1000 cycles at 5 C). These results demonstrate the great potential of TiNb2O7 as a practical high‐rate anode material for LIBs.
Modeling and simulation of an industrial‐scale parex process
Authors: Silva Marta S. P. , Rodrigues Alírio E. , Mota José P. B.
Published: January 2015

The Parex unit for industrial‐scale purification of p‐xylene was studied through detailed simulation and the accuracy of the developed model tested against real industrial data. Starting from a comprehensive analysis of the construction and operation of the industrial unit, a simulation model was developed that incorporates the existing three major types of dead volumes: bed lines, which connect the beds to the rotary valve, circulation lines, which connect adjacent adsorbent chambers, and bed‐head dead volumes, which are located upstream of each bed due to the existence of internals. By gathering operation data and surveys in the pumparound line and in the extract stream, three case studies were defined and compared with simulation results. The model is capable of predicting the performance of the industrial unit. Further simulations were made and compared with plant data to assess the effect of adsorbent capacity loss on the long‐term performance of the unit. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1345–1363, 2015
Predictors of prolonged laparoscopic cholecystectomy in the treatment of low‐grade acute cholecystitis: a single‐center, retrospective, observational study
Authors: Kaneko Tadashi , Kuwahara Taichi , Harada Toshio , Kawaoka Toru , Hiraki Sakurao , Fukuda Shintaro
Published: January 2015

Aim

Laparoscopic cholecystectomy is frequently used to treat low‐grade acute cholecystitis. Improvements in technical skills have reduced the rate of conversion from laparoscopic to open surgery. In this study, we sought to identify factors that might predict the surgical time of laparoscopic cholecystectomy as possible markers for surgical difficulty.

Methods

We carried out a single‐center retrospective analysis of a Japanese medical insurance database. Data were retrieved for 87 patients with acute cholecystitis. The analyzed factors included age, sex, body mass index, medical history, blood laboratory data, computed tomography findings, and time from disease onset to surgery. Multiple regression analysis was used to identify factors associated with surgical time.

Results

Edema of the gallbladder wall on computed tomography, neutrophil sequestration, body mass index, and history of acute cholangitis were significantly associated with surgical time (P = 0.014, 0.027, 0.043, and 0.047, respectively). The conversion rate from laparoscopic surgery to open surgery was 2%.

Conclusions

Our results suggest that edema of the gallbladder wall on computed tomography, neutrophil sequestration, body mass index, and history of acute cholangitis are associated with surgical time of laparoscopic cholecystectomy in the treatment of acute cholecystitis in our hospital.
Synthesis of Enantioenriched 5,6‐Dihydrophenanthridine Derivatives through retro‐Carbopalladation of Chiral o‐Bromobenzylamines
Authors: Ye Juntao , Limouni Aurore , Zaichuk Sonia , Lautens Mark
Published: January 2015

Retro‐carbopalladation of aldimines in the presence of a suitable β‐hydrogen atom has been observed in the Pd‐catalyzed homocoupling reactions of o‐bromobenzylamines, providing an expeditious synthetic route to 5,6‐dihydrophenanthridine derivatives. Furthermore, a highly enantioselective synthesis of 6‐aryl‐substituted 5,6‐dihydrophenanthridines was achieved in a one‐pot manner by taking advantage of Rh and Pd catalysis.
Elucidation of the Concise Biosynthetic Pathway of the Communesin Indole Alkaloids
Authors: Lin Hsiao‐Ching , Chiou Grace , Chooi Yit‐Heng , McMahon Travis C. , Xu Wei , Garg Neil K. , Tang Yi
Published: January 2015

The communesins are a prominent class of indole alkaloids isolated from Penicillium species. Owing to their daunting structural framework and potential as pharmaceuticals, communesins have inspired numerous synthetic studies. However, the genetic and biochemical basis of communesin biosynthesis has remained unexplored. Herein, we report the identification and characterization of the communesin (cns) biosynthetic gene cluster from Penicillium expansum. We confirmed that communesin is biosynthesized by the coupling of tryptamine and aurantioclavine, two building blocks derived from L‐tryptophan. The postmodification steps were mapped by targeted‐gene‐deletion experiments and the structural elucidation of intermediates and new analogues. Our studies set the stage for the biochemical characterization of communesin biosynthesis. This knowledge will aid our understanding of how nature generates remarkable structural complexity from simple precursors.
Silica–acetylacetone‐supported palladium nanoparticles as an efficient and reusable catalyst in the Heck–Mizoroki C–C cross‐coupling reaction
Authors: Hajipour Abdolreza , Shirdashtzade Zohre , Azizi Ghobad
Published: January 2015

The preparation of palladium nanoparticles supported on acetylacetone‐modified silica gel and their catalytic application for Heck olefination of aryl halides were investigated. The catalyst was characterized using X‐ray diffraction, X‐ray photoelectron spectroscopy, and transmission and scanning electron microscopies. The supported palladium nanoparticles are demonstrated to be a highly active and reusable catalyst for the Heck reaction. Several reaction parameters, including type and amount of solvent and base, were evaluated. The heterogeneity of the catalytic system was investigated with results indicating that there is a slight palladium leaching into the reaction solution under the applied reaction conditions. Despite this metal leaching, the catalyst can be reused nine times without significant loss of catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.
Facile construction of symmetric biaryls using (BeDABCO)2Pd2Cl6 as an efficient and highly active catalyst under microwave irradiation
Authors: Hajipour Abdol Reza , Rafiee Fatemeh
Published: January 2015

An efficient catalytic system using (BeDABCO)2Pd2Cl6 (BeDABCO, benzyl‐1,4‐diazabicyclo[2.2.2]octane) was developed for the homo‐coupling reaction of various aryl halides. Due to the combination of ionic homogeneous metal catalyst and microwave irradiation, symmetric biaryls were produced in excellent yields and short reaction times in N‐methyl‐2‐pyrrolidone at 120 °C. BeDABCO as an efficient ligand and also a quaternary ammonium salt had an efficient stabilizing effect on the Pd(0) species in this coupling reaction. Copyright © 2015 John Wiley & Sons, Ltd.
Preparation of segmented semifluorinated poly(aryl ether)s from aromatic trifluorovinyl ethers and oligo(ethylene glycol)s
Authors: Brown Dakarai K. , Cracowski Jean‐Marc , Iacono Scott T. , Christensen Kenneth , Smith Dennis W.
Published: January 2015

A series of new segmented semifluorinated polyaryl ethers (PAEs) containing a biphenyl segmented by semifluorinated oligoethylene (SFE) units were prepared by nucleophilic addition of a commercial oligo(ethylene glycol)s to 4,4′‐bis(4‐trifluorovinyloxy)biphenyl. These new thermoplastics were characterized by 1H and F19 nuclear magnetic resonance (NMR) and attenuated total reflectance Fourier transform infrared (ATR‐FTIR). Gel permeation chromatography (GPC) analysis displayed number average molecular weights (Mns) from 9000 to 13,000. Thermal properties of the polymers were studied by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). DSC chromatograms displayed glass transition temperatures (Tgs) from 11 to 1°C. The onsets of degradations were observed by TGA analysis between 313 to 333°C in air and 326 to 363°C in nitrogen, respectively. A second onset of degradation was observed from 452 to 470°C for all polymers. In addition, crystalline morphologies were studied by tapping mode atomic force microscopy (TM‐AFM) and showed needle‐like crystallites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41798.
Plasticizing effect of poly(ethylene glycol)s with different molecular weights in poly(lactic acid)/starch blends
Authors: Yu Yunan , Cheng Yan , Ren Jiawei , Cao Erping , Fu Xiaowei , Guo Weihong
Published: January 2015

Binary and ternary blends composed of poly(lactic acid) (PLA), starch, and poly(ethylene glycols) (PEGs) with different molecular weights (weight‐average molecular weights = 300, 2000, 4000, 6000, and 10, 000 g/mol) were prepared, and the plasticizing effect and miscibility of PEGs in poly(lactic acid)/starch (PTPS) or PLA were intensively studied. The results indicate that the PEGs were effective plasticizers for the PTPS blends. The small‐molecule plasticizers of PEG300 (i.e., the Mw of PEG was 300g/mol) and glycerol presented better plasticizing effects, whereas its migration and limited miscibility resulted in significant decreases in the water resistance and elongation at break. PEG2000, with a moderate molecular weight, was partially miscible in sample PTPS3; this led to better performance in water resistance and mechanical properties. For higher molecular weight PEG, its plasticization for both starch and PLA was depressed, and visible phase separation also occurred, especially for PTPS6. It was also found that the presence of PEG significantly decreased the glass‐transition temperature and accelerated the crystallization of the PLA matrix, depending on the PEG molecular weight and concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41808.
Oil‐absorbent polyurethane sponge coated with KH‐570‐modified graphene
Authors: Li Beibei , Liu Xiaoyan , Zhang Xinying , Zou Junchen , Chai Wenbo , Xu Jing
Published: January 2015

Polyurethane (PU) sponge has become a preferred oil adsorbent in recent oil‐spill accidents. To make the sponge superhydrophobic and superoleophilic, this study used graphene (GN), which was modified with γ‐methacryloxypropyl trimethoxy silane (KH‐570), to coat the PU sponge (called the KH–GN sponge). This study showed the best loading capacity (11.96%) of the KH‐570‐modified GN on the sponge. The contact angles of the KH–GN PU sponge were 161° for water and 0° for soybean, diesel, and pumping oil. It had good selectivity for oil over water, and the KH–GN sponge achieved adsorption equilibrium within a few seconds. The absorption capability of the KH–GN sponge was up to 39 times greater. Additionally, the KH–GN PU sponge could be reused for oil–water separation for more than 120 cycles without losing its superhydrophobic and superoleophilic properties. Therefore, the sponge prepared in this study could be a desirable material for the cleanup of oil spills. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41821.
Effect of graphene loading on thermomechanical properties of poly(vinyl alcohol)/starch blend
Authors: Jose Jobin , Al‐Harthi Mamdouh A. , AlMa'adeed Mariam Al‐Ali , Bhadra Dakua Jolly , De Sadhan K.
Published: January 2015

Polymer nanocomposites based on poly(vinyl alcohol) (PVA)/starch blend and graphene were prepared by solution mixing and casting. Glycerol was used as a plasticizer and added in the starch dispersion. The uniform dispersion of graphene in water was achieved by using an Ultrasonicator Probe. The composites were characterized by FTIR, tensile properties, X‐ray diffraction (XRD), thermal analysis, and FE‐SEM studies. FTIR studies indicated probable hydrogen bonding interaction between the oxygen containing groups on graphene surface and the –OH groups in PVA and starch. Mechanical properties results showed that the optimum loading of graphene was 0.5 wt % in the blend. XRD studies indicated uniform dispersion of graphene in PVA/starch matrix upto 0.5 wt % loadings and further increase caused agglomeration. Thermal studies showed that the thermal stability of PVA increased and the crystallinity decreased in the presence of starch and graphene. FE‐SEM studies showed that incorporation of graphene increased the ductility of the composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41827.
Enhanced mechanical strength and conductivity of PVFM based membrane and its supporting polymer electrolytes
Authors: Pan Xiao‐rong , Lian Fang , He Yi , Peng Yi‐fei , Sun Xiao‐meng , Wen Yan , Guan Hong‐yan
Published: January 2015

Polyvinyl formal based polymer electrolyte membranes are prepared via the optimized phase inversion method with poly(ethylene oxide) (PEO) blending. The physical properties of blend membranes and the electrochemical properties of corresponding gel polymer electrolytes (GPEs) are characterized by field emission scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, mechanical strength test, electrolyte uptake test, AC impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge test. The comparative study shows that the appearance of PEO obviously enhances the tensile strength of membranes and the ionic conductivity of corresponding GPEs. When the weight ratio of PEO is 30%, the tensile strength of membrane achieves 12.81 MPa, and its GPE shows high ionic conductivity of 2.20 × 10−3 S cm−1, wide electrochemical stable window of 1.9–5.7 V (vs. Li/Li+), and good compatibility with LiFePO4 electrode. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41839.
Water‐resistant plant protein‐based nanofiber membranes
Authors: Lubasova Daniela , Mullerova Jana , Netravali Anil N.
Published: January 2015

Developing green and sustainable alternative materials to replace petroleum based ones is the need of the day. Such green materials are becoming popular because they can be composted once their useful life is over. In the current research, protein‐based nanofibers were fabricated without the use of any toxic cross‐linking agent. Defatted soy flour was purified using an acid‐wash process to obtain material with higher protein content, blended with gluten, and successfully electrospun into nanofibers with the help of polyvinyl alcohol. Oxidation of sucrose with hydrogen peroxide (H2O2) was carried out to synthesize oxidized sugar‐containing aldehyde (—CHO) groups and used as green cross‐linker. The cross‐linking quality of protein‐based nanofibers modified by oxidized sugar was found to be similar to nanofibers cross‐linked using toxic glyoxal and show good resistance to water. These novel green protein‐based nanofibers can be useful in fabricating inexpensive products with very high specific surface area and highly porous structure. © 2015 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41852.
Covalently bound organomodified clay photoinitiators
Authors: Davidson Barret J. , Gee Samuel J. , Hurst Grayson C. , Rucker Joshua B. , Shouse Jonathan L. , Smith Joshua B. , Cavitt T. Brian
Published: January 2015

While organomodified clays are property enhancing additives for composite materials, much of the research thereof has focused on intercalated quaternary ammonium compounds; however, herein the effects of covalently bound organomodified clays (CoBOCs) are explored with particular emphasis on CoBOC photoinitiators. Two commercially available alcoholic photoinitiators (1‐hydroxycyclohexyl phenyl ketone and 2‐hydroxy‐2‐methyl‐1‐phenylpropanone) were reacted with isophorone diisocyanate to form half‐adducts and then reacted with Cloisite 93A, an organophilic montmorillonite clay, to form two CoBOC photoinitiators. The CoBOC photoinitiators were integrated into a standard formulation and subsequently ultraviolet (UV) cured. Property characterization thereof (e.g., adhesion, hardness, and flexibility) yielded unchanged or increased properties with the exception of impact flexibility. Finally, the CoBOC photoinitiators were kinetically characterized via photo‐differential scanning calorimetry (photo‐DSC) within 1,6‐hexanediol diacrylate (HDODA). While increasing concentrations of clay additives generally decrease polymerization rates, increasing concentrations of the CoBOC photoinitiators exhibited increased polymerization rates. Therefore, the CoBOC photoinitiators can enhance the polymerization kinetics and physical properties of UV‐curable coatings. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41883.
Synthesis and characterization of maleated rosin‐modified fluorosilicone resin and its fluorosilicone rubber
Authors: Xu Tao , Liu He , Song Jie , Shang Shi‐bin , Song Zhanqian , Zou Kaifei , Yang Chong
Published: January 2015

Imide‐containing vinyl fluorosilicone resin (MR‐VFS) was synthesized from maleated rosin (MR). And then, with MR‐VFS as a new polar cross‐linking agent in a heat curable fluorosilicone rubber composition, a series of maleated rosin‐modified fluorosilicone rubbers (MR‐FSR) were obtained. The effects of MR‐VFS on the mechanical properties, oil resistance, thermal stability, and low‐temperature performance were studied in detail. It was found that MR‐VFS could increase the tearing strength and high‐temperature thermal stability of fluorosilicone rubber. When the MR‐VFS weight content reached to 2 wt %, the tearing strength of MR‐FSR increased by 20.1% compared with that of common fluorosilicone rubber. However, MR‐FSR showed a similar low‐temperature resistance and a little worse oil resistance. The morphological study showed that incorporation of maleated rosin could intensify the microphase separation of fluorosilicone rubber. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41888.
Properties and application of polyimide‐based composites by blending surface functionalized boron nitride nanoplates
Authors: Chen Yuanming , Gao Xing , Wang Jinling , He Wei , Silberschmidt Vadim V. , Wang Shouxu , Tao Zhihua , Xu Huan
Published: January 2015

Ball milling was used to decrease the particle size of boron nitride (BN) nanoplates and to form more silylated functionalization of their surface. Such functionalized BN nanoplates enhanced their homogeneous dispersion in polyimide (PI) matrix. Thermal conductivities, thermal stabilities, and dielectric properties were characterized to investigate the particular effects on the performance of PI‐based composites with functionalized BN nanoplates. When the concentration of functionalized BN nanoplates increased to 50 wt %, thermal conductivity of the composite increased up to 1.583 W m−1 K−1, and the temperature of final thermal decomposition was improved to 600°C. An increasing trend was found in the dielectric constant of the composites while the dielectric loss decreased with the increase in the fraction. An appropriate fraction of functionalized BN nanoplates in PI‐based composites were necessary to meet the requirement of withstanding drilling forces for the interconnecting through holes of flexible circuits. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41889.
THE INFLUENCE OF A 21 kDa KUNITZ‐TYPE TRYPSIN INHIBITOR FROM NONHOST MADRAS THORN, Pithecellobium dulce, SEEDS ON H. armigera (HÜBNER) (LEPIDOPTERA: NOCTUIDAE)
Authors: Pandey Prabhash K. , Singh Dushyant , Jamal Farrukh
Published: January 2015

A trypsin inhibitor purified from the seeds of the Manila tamarind, Pithecellobium dulce (PDTI), was studied for its effects on growth parameters and developmental stages of  Helicoverpa armigera. PDTI exhibited inhibitory activity against bovine trypsin (∼86%; ∼1.33 ug/ml IC50). The inhibitory activity of PDTI was unaltered over a wide range of temperature, pH, and in the presence of dithiothreitol. Larval midgut proteases were unable to digest PDTI for up to 12 h of incubation. Dixon and Lineweaver–Burk double reciprocal plots analysis revealed a competitive inhibition mechanism and a Ki of ∼3.9 × 10−8 M. Lethal dose (0.50% w/w) and dosage for weight reduction by 50% (0.25% w/w) were determined. PDTI showed a dose‐dependent effect on mean larval weight and a series of nutritional disturbances. In artificial diet at 0.25% w/w PDTI, the efficiency of conversion of ingested food, of digested food, relative growth rate, and growth index declined, whereas approximate digestibility, relative consumption rate, metabolic cost, consumption index, and total developmental period were increased in larvae. This is the first report of antifeedant and antimetabolic activities of PDTI on midgut proteases of  H. armigera.
Piperazine Analogs of Naphthyridine‐3‐carboxamides and Indole‐2‐carboxamides: Novel 5‐HT3 Receptor Antagonists with Antidepressant‐Like Activity
Authors: Dhar Arghya K. , Mahesh Radhakrishnan , Jindal Ankur , Bhatt Shvetank
Published: January 2015

Series of piperazine analogs of naphthyridine‐3‐carboxamides and indole‐2‐carboxamides were designed using a ligand‐based approach with consideration of the pharmacophoric requirements for 5‐HT3 receptor antagonists. The title carboxamides were synthesized using appropriate synthetic routes. Initially, the 5‐HT3 receptor antagonistic activity of all the compounds was determined on isolated guinea pig ileum tissue against the 5‐HT3 agonist, 2‐methyl‐5‐hydroxytryptamine, which was denoted in the form of pA2 values. The structure–activity relationship regarding the influence of the aromatic part and basic moiety as features in the 5‐HT3 pharmacophore was derived. Among all the compounds screened, the piperazine derivatives of indole‐2‐carboxamide 13i and naphthyridine‐3‐carboxamide 8h exhibited prominent 5‐HT3 receptor antagonism with pA2 values of 7.5 and 7.3, respectively. Subsequent investigation of the antidepressant activities of selected compounds in the mouse forced swim test (FST) led to the identification of the piperazine analogs of indole‐2‐carboxamide 13i and naphthyridine‐3‐carboxamide 8h as the most promising compounds. Both 13i and 8h demonstrated significant reduction in the duration of immobility as compared to the control. Importantly, none of the tested compounds affected the baseline locomotion of mice at the tested dose levels.
Synthesis and Cytotoxic Activity of Pentacyclic Triterpenoid Sulfamates
Authors: Sommerwerk Sven , Heller Lucie , Csuk René
Published: January 2015

Methyl triterpenoates derived from oleanolic, ursolic, betulinic, glycyrrhetinic, platanic, or maslinic acid were converted into their corresponding sulfamates and carbamoylsulfamates. The sulfamates were screened in photometric sulforhodamine assays for cytotoxic activity employing several human tumor cell lines. Many of the compounds showed EC50 values in one‐digit μM concentration. Of special interest seems methyl (3β) 3‐(aminosulfonyloxy)‐11‐oxo‐oleanoate (18) showing good cytotoxicity for the human adenocarcinomic alveolar basal epithelial cell line A549 while being less toxic for non‐malignant NIH 3T3 mouse fibroblasts.
The student's dilemma, liver edition: Incorporating the sonographer's language into clinical anatomy education
Authors: Hall M. Kennedy , Mirjalili S. Ali , Moore Christopher L. , Rizzolo Lawrence J.
Published: January 2015

Anatomy students are often confused by multiple names ascribed to the same structure by different clinical disciplines. Increasingly, sonography is being incorporated into clinical anatomical education, but ultrasound textbooks often use names unfamiliar to the anatomist. Confusion is worsened when ultrasound names ascribed to the same structure actually refer to different structures. Consider the sonographic main lobar fissure (MLF). The sonographic MLF is a hyper‐echoic landmark used by sonographers of the right upper quadrant. Found in approximately 70% of people, there is little consensus on what the sonographic MLF is anatomically. This structure appears to be related to the main portal fissure (aka principal plane of the liver or principal hepatic fissure), initially described by anatomists and surgeons as in intrahepatic division along the middle hepatic vein which in essence divides the territories of the left and right hepatic arteries and biliary systems. By exploring the relationship between the main portal fissure and the sonographic MLF in cadaveric livers ex vivo, the data suggest the sonographic MLF is actually an extrahepatic structure that parallels the rim of the main portal fissure. The authors recommend that this structure be renamed the “sonographic cystic pedicle,” which includes the cystic duct and ensheathing fat and blood vessels. In the context of the redefined underlying anatomy, the absence of the sonographic cystic pedicle due to anatomic variation may serve an important clinical role in predicting complications from difficult laparoscopic cholecystectomies and is deserving of future study. Anat Sci Educ 8: 283–288. © 2015 American Association of Anatomists.
Aggregated journal–journal citation relations in scopus and web of science matched and compared in terms of networks, maps, and interactive overlays
Authors: Leydesdorff Loet , de Moya‐Anegón Félix , de Nooy Wouter
Published: January 2015

We compare the network of aggregated journal–journal citation relations provided by the Journal Citation Reports (JCR) 2012 of the Science Citation Index (SCI) and Social Sciences Citation Index (SSCI) with similar data based on Scopus 2012. First, global and overlay maps were developed for the 2 sets separately. Using fuzzy‐string matching and ISSN numbers, we were able to match 10,524 journal names between the 2 sets: 96.4% of the 10,936 journals contained in JCR, or 51.2% of the 20,554 journals covered by Scopus. Network analysis was pursued on the set of journals shared between the 2 databases and the 2 sets of unique journals. Citations among the shared journals are more comprehensively covered in JCR than in Scopus, so the network in JCR is denser and more connected than in Scopus. The ranking of shared journals in terms of indegree (i.e., numbers of citing journals) or total citations is similar in both databases overall (Spearman rank correlation ρ > 0.97), but some individual journals rank very differently. Journals that are unique to Scopus seem to be less important—they are citing shared journals rather than being cited by them—but the humanities are covered better in Scopus than in JCR.
A new approach for main path analysis: Decay in knowledge diffusion
Authors: Liu John S. , Kuan Chung‐Huei
Published: January 2015

Main path analysis is a powerful tool for extracting the backbones of a directed network and has been applied widely in bibliometric studies. In contrast to the no‐decay assumption in the traditional approach, this study proposes a novel technique by assuming that the strength of knowledge decays when knowledge contained in one document is passed on to another document down the citation chain. We propose three decay models, arithmetic decay, geometric decay, and harmonic decay, along with their theoretical properties. In general, results of the proposed decay models depend largely on the local structure of a citation network as opposed to the global structure in the traditional approach. Thus, the significance of citation links and the associated documents that are overemphasized by the global structure in the traditional no‐decay approach is treated more properly. For example, the traditional approach commonly assigns high value to documents that heavily reference others, such as review articles. Specifically in the geometric and harmonic decay models, only truly significant review articles will be included in the resulting main paths. We demonstrate this new approach and its properties through the DNA literature citation network.
Dimensions and uncertainties of author citation rankings: Lessons learned from frequency‐weighted in‐text citation counting
Authors: Zhao Dangzhi , Strotmann Andreas
Published: January 2015

In‐text frequency‐weighted citation counting has been seen as a particularly promising solution to the well‐known problem of citation analysis that it treats all citations equally, be they crucial to the citing paper or perfunctory. But what is a good weighting scheme? We compare 12 different in‐text citation frequency‐weighting schemes in the field of library and information science (LIS) and explore author citation impact patterns based on their performance in these schemes. Our results show that the ranks of authors vary widely with different weighting schemes that favor or are biased against common citation impact patterns—substantiated, applied, or noted. These variations separate LIS authors quite clearly into groups with these impact patterns. With consensus rank limits, the hard upper and lower bounds for reasonable author ranks that they provide suggest that author citation ranks may be subject to something like an uncertainty principle.
An ontology‐based model for indexing and retrieval
Authors: Gödert Winfried
Published: January 2015

The presented ontology‐based model for indexing and retrieval combines the methods and experiences of traditional indexing languages with their cognitively interpreted entities and relationships with the strengths and possibilities of formal knowledge representation. The core component of the model uses inferences along the paths of typed relations between the entities of a knowledge representation for enabling the determination of result sets in the context of retrieval processes. A proposal for a general, but condensed, inventory of typed relations is given. The entities are arranged in aspect‐oriented facets to ensure a consistent hierarchical structure. The possible consequences for indexing and retrieval are discussed.
Comparing keywords plus of WOS and author keywords: A case study of patient adherence research
Authors: Zhang Juan , Yu Qi , Zheng Fashan , Long Chao , Lu Zuxun , Duan Zhiguang
Published: January 2015

Bibliometric analysis based on literature in the Web of Science (WOS) has become an increasingly popular method for visualizing the structure of scientific fields. Keywords Plus and Author Keywords are commonly selected as units of analysis, despite the limited research evidence demonstrating the effectiveness of Keywords Plus. This study was conceived to evaluate the efficacy of Keywords Plus as a parameter for capturing the content and scientific concepts presented in articles. Using scientific papers about patient adherence that were retrieved from WOS, a comparative assessment of Keywords Plus and Author Keywords was performed at the scientific field level and the document level, respectively. Our search yielded more Keywords Plus terms than Author Keywords, and the Keywords Plus terms were more broadly descriptive. Keywords Plus is as effective as Author Keywords in terms of bibliometric analysis investigating the knowledge structure of scientific fields, but it is less comprehensive in representing an article's content.
Exploring information interactions in the context of Google
Authors: Johnson Frances , Rowley Jennifer , Sbaffi Laura
Published: January 2015

The study sets out to explore the factors that influence the evaluation of information and the judgments made in the process of finding useful information in web search contexts. Based on a diary study of 2 assigned tasks to search on Google and Google Scholar, factor analysis identified the core constructs of content, relevance, scope, and style, as well as informational and system “ease of use” as influencing the judgment that useful information had been found. Differences were found in the participants' evaluation of information across the search tasks on Google and on Google Scholar when identified by the factors related to both content and ease of use. The findings from this study suggest how searchers might critically evaluate information, and the study identifies a relation between the user's involvement in the information interaction and the influences of the perceived system ease of use and information design.
A Ring‐Flippable Sugar as a Stimuli‐Responsive Component of Liposomes
Authors: Takeuchi Junji , Ohkubo Akihiro , Yuasa Hideya
Published: January 2015

For the development of a liposome that takes in and out a drug in response to stimuli, 2,4‐diaminoxylose (Xyl), which allows stimuli‐responsive conformational switches between 4C1 and 1C4, was incorporated into a lipid structure: Xyl derivatives with C8 and C16 methylene chains at the 1,3‐positions (C8Xyl and C16Xyl) were synthesized. 1H NMR spectroscopy indicates that the addition of Zn2+ and then H+ induces conformational switches from the chair (4C1) to the reverse chair (1C4) and 1C4‐to‐4C1, respectively, at Xyl; this leads to transformation of the lipids between linear and bent structures. Osmotic pressure and electron microscopy studies demonstrate that C8Xyl in water forms spherical solid aggregates (C8Xyl−Zn), which are converted into liposomes (C8Xyl+Zn) upon the addition of Zn2+, and C16Xyl forms liposomes regardless of the presence of Zn2+. The aggregates of C8Xyl±Zn incorporated a fluorophore and only C8Xyl+Zn released the content upon the addition of HCl. This study shows that Xyl could be a stimuli‐responsive component of a liposome.
Zur Orthotropie der physikalisch‐mechanischen Eigenschaften von Rotbuchenholz
Authors: Niemz Peter , Ozyhar Tomasz , Hering Stefan , Sonderegger Walter
Published: January 2015

Zunehmend wird versucht, Laubholz im Bauwesen einzusetzen, um größere Mengen stofflich zu verwerten und gleichzeitig die im Vergleich zum Nadelholz verbesserten mechanischen Eigenschaften des Laubholzes konstruktiv zu nutzen. Für die teilweise dazu erforderlichen Berechnungen der Verformung von Platten oder auch von Spannungen in Brettschichtholz (z. B. Vorausberechnung von eventuellen Delaminierungen oder der Alterung von Klebverbindungen) ist die Kenntnis der richtungsabhängigen Kennwerte des Holzes in den Hauptachsen längs, radial und tangential erforderlich. Dies betrifft die elastischen Kennwerte (E‐Modul, Schubmodul, Querdehnzahl), die Festigkeiten (auf Zug, Druck, Biegung und Scherung) und auch die Kennwerte für den Feuchte‐ und Wärmetransport (Diffusionskoeffizient, Wärmeleitfähigkeit). Für alle Kennwerte ist zudem die Kenntnis der Abhängigkeit von der Holzfeuchte und der Zeit notwendig. Ausgewählte Parameter für die Richtungs‐ und Feuchteabhängigkeit bei Rotbuchenholz werden für E‐Modul, Schubmodul und Querdehnzahl sowie die Wärmeleitfähigkeit und die Diffusionskonstante vorgestellt. Die Ergebnisse fassen an der ETH Zürich, Arbeitsgruppe Holzphysik, durchgeführte Arbeiten zur Thematik zusammen.

The orthotropic behaviour of the physical‐mechanical properties of European beech wood

Hardwood is tried to be increasingly established in building industry in order to realise a larger material output and to take at once into account the structural advantage of the improved mechanical properties of hardwood in comparison to softwood. For the partially required calculations therefore of stress and strain in boards and glued‐laminated timbers (for example prognosis of potential delamination and aging of glued joints), it is essential to know the directional specific values of wood in the directions longitudinal, radial and tangential. This concerns the elastic specific values (YOUNG's modulus, shear modulus, POISSON's ratio), the specific values of strength (tension, compression, bending, shear) and also these of mass and heat flux (diffusion coefficient, thermal conductivity). Additionally, it is necessary to know the dependencies from moisture and duration for all specific values. Selected parameters for European beech wood will be presented concerning the dependencies of YOUNG's modulus, shear modulus, POISSON's ratio, thermal conductivity and diffusion coefficient from direction and moisture. The results summarize investigations on this topic realised at the Wood Physics Group of ETH Zurich.
Inkjet‐bioprinted acrylated peptides and PEG hydrogel with human mesenchymal stem cells promote robust bone and cartilage formation with minimal printhead clogging
Authors: Gao Guifang , Yonezawa Tomo , Hubbell Karen , Dai Guohao , Cui Xiaofeng
Published: January 2015

Inkjet bioprinting is one of the most promising additive manufacturing approaches for tissue fabrication with the advantages of high speed, high resolution, and low cost. The limitation of this technology is the potential damage to the printed cells and frequent clogging of the printhead. Here we developed acrylated peptides and co‐printed with acrylated poly(ethylene glycol) (PEG) hydrogel with simultaneous photopolymerization. At the same time, the bone marrow‐derived human mesenchymal stem cells (hMSCs) were precisely printed during the scaffold fabrication process so the cells were delivered simultaneously with minimal UV exposure. The multiple steps of scaffold synthesis and cell encapsulation were successfully combined into one single step using bioprinting. The resulted peptide‐conjugated PEG scaffold demonstrated excellent biocompatibility, with a cell viability of 87.9 ± 5.3%. Nozzle clogging was minimized due to the low viscosity of the PEG polymer. With osteogenic and chondrogenic differentiation, the bioprinted bone and cartilage tissue demonstrated excellent mineral and cartilage matrix deposition, as well as significantly increased mechanical properties. Strikingly, the bioprinted PEG‐peptide scaffold dramatically inhibited hMSC hypertrophy during chondrogenic differentiation. Collectively, bioprinted PEG‐peptide scaffold and hMSCs significantly enhanced osteogenic and chondrogenic differentiation for robust bone and cartilage formation with minimal printhead clogging.
Production of curcuminoids from tyrosine by a metabolically engineered Escherichia coli using caffeic acid as an intermediate
Authors: Rodrigues Joana L. , Araújo Rafael G. , Prather Kristala L. J. , Kluskens Leon D. , Rodrigues Ligia R.
Published: January 2015

Curcuminoids are phenylpropanoids with high pharmaceutical potential. Herein, we report an engineered artificial pathway in Escherichia coli to produce natural curcuminoids through caffeic acid. Arabidopsis thaliana 4‐coumaroyl‐CoA ligase and Curcuma longa diketide‐CoA synthase (DCS) and curcumin synthase (CURS1) were used to produce curcuminoids and 70 mg/L of curcumin was obtained from ferulic acid. Bisdemethoxycurcumin and demethoxycurcumin were also produced, but in lower concentrations, by feeding p‐coumaric acid or a mixture of p‐coumaric acid and ferulic acid, respectively. Additionally, curcuminoids were produced from tyrosine through the caffeic acid pathway. To produce caffeic acid, tyrosine ammonia lyase from Rhodotorula glutinis and 4‐coumarate 3‐hydroxylase from Saccharothrix espanaensis were used. Caffeoyl‐CoA 3‐O‐methyltransferase from Medicago sativa was used to convert caffeoyl‐CoA to feruloyl‐CoA. Using caffeic acid, p‐coumaric acid or tyrosine as a substrate, 3.9, 0.3, and 0.2 mg/L of curcumin were produced, respectively. This is the first time DCS and CURS1 were used in vivo to produce curcuminoids and that curcumin was produced by feeding tyrosine. We have shown that curcumin can be produced using a pathway involvoing caffeic acid. This alternative pathway represents a step forward in the heterologous production of curcumin using E. coli.
Encapsulation of enzyme via one‐step template‐free formation of stable organic–inorganic capsules: A simple and efficient method for immobilizing enzyme with high activity and recyclability
Authors: Huang Renliang , Wu Mengyun , Goldman Mark J. , Li Zhi
Published: January 2015

Enzyme encapsulation is a simple, gentle, and general method for immobilizing enzyme, but it often suffers from one or more problems regarding enzyme loading efficiency, enzyme leakage, mechanical stability, and recyclability. Here we report a novel, simple, and efficient method for enzyme encapsulation to overcome these problems by forming stable organic–inorganic hybrid capsules. A new, facile, one‐step, and template‐free synthesis of organic–inorganic capsules in aqueous phase were developed based on PEI‐induced simultaneous interfacial self‐assembly of Fmoc‐FF and polycondensation of silicate. Addition of an aqueous solution of Fmoc‐FF and sodium silicate into an aqueous solution of PEI gave a new class of organic–inorganic hybrid capsules (FPSi) with multi‐layered structure in high yield. The capsules are mechanically stable due to the incorporation of inorganic silica. Direct encapsulation of enzyme such as epoxide hydrolase SpEH and BSA along with the formation of the organic–inorganic capsules gave high yield of enzyme‐containing capsules (∼1.2 mm in diameter), >90% enzyme loading efficiency, high specific enzyme loading (158 mg protein g−1 carrier), and low enzyme leakage (<3% after 48 h incubation). FPSi‐SpEH capsules catalyzed the hydrolysis of cyclohexene oxide to give (1R, 2R)‐cyclohexane‐1,2‐diol in high yield and concentration, with high specific activity (6.94 U mg−1 protein) and the same high enantioselectivity as the free enzyme. The immobilized SpEH demonstrated also excellent operational stability and recyclability: retaining 87% productivity after 20 cycles with a total reaction time of 80 h. The new enzyme encapsulation method is efficient, practical, and also better than other reported encapsulation methods. Biotechnol. Bioeng. 2015;112: 1092–1101. © 2015 Wiley Periodicals, Inc.
Synergetic Effects Leading to Coke‐Resistant NiCo Bimetallic Catalysts for Dry Reforming of Methane
Authors: Li Lidong , Anjum Dalaver H. , Zhu Haibo , Saih Youssef , Laveille Paco V. , D'Souza Lawrence , Basset Jean‐Marie
Published: January 2015

A new dry reforming of methane catalyst comprised of NiCo bimetallic nanoparticles and a Mgx(Al)O support that exhibits high coke resistance and long‐term on‐stream stability is reported. The structural characterization by XRD, TEM, temperature‐programmed reduction, and BET analysis demonstrates that the excellent performance of this catalyst is ascribed to the synergy of various parameters, including metal‐nanoparticle size, metal–support interaction, catalyst structure, ensemble size, and alloy effects.
Fouling Resistance on Chemically Etched Hydrophobic Surfaces in Nucleate Pool Boiling
Authors: Hui Longfei , Liu Mingyan , Cai Yongwei , Lv Yan
Published: January 2015

Chemical etching, liquid phase deposition, and dipping techniques were utilized to fabricate highly hydrophobic micro‐ and nanoscale coating surfaces on stainless‐steel substrates. Heat transfer and fouling characteristics on these surfaces in pool boiling of deionized water and CaSO4 solution were studied. High roughness and hydrophobicity of coated surfaces were obtained on chemically etched substrates. Compared to the polished stainless‐steel surface, the chemically etched coating surface provided a three times enhanced nucleate boiling coefficient at high heat flux. Obvious decrease of CaSO4 fouling resistance was obtained on chemically etched surfaces due to the higher roughness and hydrophobicity before the fouling resistance reaches the asymptotic value. Slightly high asymptotic fouling resistance was observed compared with coating surfaces without chemical etching of substrates.
Nano‐/Microstructured Si/C Composite with High Tap Density as an Anode Material for Lithium‐Ion Batteries
Authors: Liu Jie , Zhang Qian , Wu Zhan‐Yu , Li Jun‐Tao , Huang Ling , Sun Shi‐Gang
Published: January 2015

Nanostructured Si materials are plagued by having a limited electrochemical performance and low tap density. Hence, we synthesized a nano‐/microstructured Si/C composite with Si nanoparticles uniformly embedded into a carbon matrix, which had a tap density 5.3 times higher than that of Si nanoparticles. The nano‐/microstructured Si/C composite shows a superior structural stability, which ensures a long cycle life with a capacity of 600 mAh g−1 after 1000 cycles at 420 mA g−1. Moreover, the carbon matrix can provide three‐dimensional electron‐transfer pathways for Si nanoparticles to improve the electronic conductivity. Therefore, the Si/C composite anode material also exhibits an outstanding rate capability, which can still deliver a capacity of 510 mAh g−1 at 5 C. Thus, the nano‐/microstructured Si/C composite with a high tap density possesses great potential in view of practical applications.
Precise Measurement of Long‐Range Heteronuclear Coupling Constants by a Novel Broadband Proton–Proton‐Decoupled CPMG‐HSQMBC Method
Authors: Timári István , Illyés Tünde Z. , Adams Ralph W. , Nilsson Mathias , Szilágyi László , Morris Gareth A. , Kövér Katalin E.
Published: January 2015

A broadband proton–proton‐decoupled CPMG‐HSQMBC method for the precise and direct measurement of long‐range heteronuclear coupling constants is presented. The Zangger–Sterk‐based homodecoupling scheme reported herein efficiently removes unwanted proton–proton splittings from the heteronuclear multiplets, so that the desired heteronuclear couplings can be determined simply by measuring frequency differences between singlet maxima in the resulting spectra. The proposed pseudo‐1D/2D pulse sequences were tested on nucleotides, a metal complex incorporating P heterocycles, and diglycosyl (di)selenides, as well as on other carbohydrate derivatives, for the extraction of nJ(1H,31P), nJ(1H,77Se), and nJ(1H,13C) values, respectively.
Ring Opening of Donor–Acceptor Cyclopropanes with the Azide Ion: A Tool for Construction of N‐Heterocycles
Authors: Ivanov Konstantin L. , Villemson Elena V. , Budynina Ekaterina M. , Ivanova Olga A. , Trushkov Igor V. , Melnikov Mikhail Ya.
Published: January 2015

A general method for ring opening of various donor–acceptor cyclopropanes with the azide ion through an SN2‐like reaction has been developed. This highly regioselective and stereospecific process proceeds through nucleophilic attack on the more‐substituted C2 atom of a cyclopropane with complete inversion of configuration at this center. Results of DFT calculations support the SN2 mechanism and demonstrate good qualitative correlation between the relative experimental reactivity of cyclopropanes and the calculated energy barriers. The reaction provides a straightforward approach to a variety of polyfunctional azides in up to 91 % yield. The high synthetic utility of these azides and the possibilities of their involvement in diversity‐oriented synthesis were demonstrated by the developed multipath strategy of their transformations into five‐, six‐, and seven‐membered N‐heterocycles, as well as complex annulated compounds, including natural products and medicines such as (−)‐nicotine and atorvastatin.