bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ester‐Directed Selective Olefination of Acrylates by Rhodium Catalysis
Authors: Feng Ruokun , Yu Wenlong , Wang Kai , Liu Zhanxiang , Zhang Yuhong 
Published: May 2014

AbstractEster‐directed olefination of acrylates via rhodium(III)‐catalysis was developed. Various alkenes were reacted with acrylates to give the desired products in high stereoselectivity. Mechanistic investigations revealed that ester‐directed CH bond activation was the key step to this reaction.magnified image
Application of Taguchi Method to Investigate the Drug Release Behavior of Poly(Acrylamide‐co‐Maleic Acid)/Montmorillonite Nanocomposite Hydrogels
Authors: Dadkhah Daniyal , Navarchian Amir H. , Aref Latif , Tavakoli Naser 
Published: May 2014

ABSTRACTThe pH‐sensitive poly(acrylamide‐co‐maleic acid)/montmorillonite (P(AAm‐MA)/MMT) nanocomposite hydrogels were synthesized through in situ polymerization. The chemical structure and morphology of nanocomposites were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and transmission electron microscopy. The resulted disks were then loaded by caffeine, a moderately soluble model drug, using soaking method. The swelling and the drug release experiments were carried out in enzyme‐free simulated gastric and intestinal fluids. The release experiments showed that with the addition of MMT, the burst effect is well controlled, and the barrier property of nanocomposite hydrogels is improved. The effects of some compositional parameters including maleic acid to acrylamide (MA/AAm) molar ratio (MAR), weight percent of MMT (MMT%), cross‐linker/AAm molar ratio (CR), and also the influence of pH of medium on the equilibrium swelling ratio (Q) as well as caffeine release behavior of disks were studied by Taguchi method. The results indicated that shifting the pH value from 1.2 to 7.4 leads to a greater Q. The Q value and the release percentage (P%) increased with increasing the MAR in the structure of disks at pH 7.4. The amounts of P% and Q in both external media decreased with increasing both MMT% and CR. Mathematical behavior of release process was well represented by Peppas Power law model (at short times) and a two‐dimensional Fickian mass transfer model (at long times). The caffeine release behavior in both media was corresponded to the non‐Fickian transport mechanism.
Locals, resettlers, and pilgrims: A genetic portrait of three pre‐Columbian Andean populations
Authors: Baca Mateusz , Molak Martyna , Sobczyk Maciej , Węgleński Piotr , Stankovic Anna 
Published: May 2014

ABSTRACTThe common practice of resettlement and the development of administrative and ceremonial systems shaped the population landscape of the Andean region under the Inca rule. The area surrounding Coropuna and Solimana volcanoes, in the Arequipa region (Peru), carried a high‐density, multiethnic population. We studied the genetic variation among three pre‐Columbian populations from three functionally diverse archaeological sites excavated in this region. By analyzing the genetic composition of a large ceremonial center (Acchaymarca), an isolated pastoral settlement (Tompullo 2), and an agricultural settlement characterized by architectural features rare in the region (Puca), we investigated the patterns of population movements and the distribution of genetic diversity. We obtained mitochondrial DNA sequences for 25 individuals and autosomal microsatellite profiles for 20 individuals from Acchaymarca and Puca sites. These were compared with previously published genetic data for Tompullo 2 and other pre‐Columbian populations. We found differences among the genetic portraits of the three populations, congruent with the archaeologically described functions and characteristics of the sites. The Acchaymarca population had the highest genetic diversity and possessed the lowest number of unique mtDNA haplotypes. The Tompullo 2 population exhibited the lowest level of genetic diversity. The Puca population was distinct from the other two populations owing to a high frequency of haplogroup A haplotypes, what potentially explains the non‐local character of the burial architecture. Our analyses of microsatellite data suggest that gene flow between sites was mostly mediated by females, which is consistent with ethnohistorical knowledge of the social organization of the pre‐Columbian communities. Am J Phys Anthropol 154:402–412, 2014. © 2014 Wiley Periodicals, Inc.
Neue chemische Strukturen durch Mikrofluidiksysteme
Authors: Rodrigues Tiago , Schneider Petra , Schneider Gisbert 
Published: May 2014

AbstractMikrofluidiksysteme werden für viele Anwendungen im Bereich der chemischen Forschung und Entwicklung eingesetzt, einschließlich der Miniaturisierung von (bio)organischen Synthese‐ und (Bio)analysemethoden. Gegenwärtig beobachten wir den stetig wachsenden Einsatz von Mikrofluidikverfahren bei der Erforschung neuer chemischer Substanzen. Diese neuen Techniken haben bereits einen spürbaren Einfluss auf die chemische Biologie und molekulare Medizin. In diesem Kurzaufsatz beschreiben wir den aktuellen Stand der Forschung und stellen die jüngsten Fortschritte für die Anwendung von Mikrochip‐Reaktoren sowie kleinen und mittelgroßen Coil‐Reaktoren in der Synthese bioaktiver Substanzen vor und geben einen Ausblick auf mögliche künftige Anwendungen dieser vielversprechenden Technologie.
Effect of geometry and loading fractions on energy absorbing properties of fiberglass polymer composite under quasi‐static and low‐velocity impact loadings
Authors: Kim Hyung‐Ick , Jang Hong‐Kyu , Lee Stephanie K. , Suhr Jonghwan 
Published: May 2014

ABSTRACTThe focus of this study is to experimentally investigate the mechanical properties of fiberglass reinforced composite with various aspect ratios and loading fractions in the quasi‐static and low‐velocity impact loading conditions. In this study, short fiberglass reinforced polycarbonate composite materials were fabricated via a solution mixing method and characterized for their tensile properties by varying both fiberglass loading fraction and aspect ratio. The tensile properties including tensile toughness of the fiberglass reinforced composites were characterized and compared. It was observed in this study that the toughness of the composite was dramatically improved whereas the tensile strength and Young's modulus were moderately enhanced over the neat polymer, which were measured to be only up to 15% and 70% increase, respectively. The low‐velocity impact behaviors of the fiberglass composites were also investigated and compared to the tensile toughness of the corresponding composites. Besides, the effect of thickness on their low‐velocity impact properties was investigated. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40821.
Effects of an itaconic acid comonomer on the structural evolution and thermal behaviors of polyacrylonitrile used for polyacrylonitrile‐based carbon fibers
Authors: Fu Zhongyu , Gui Yu , Liu Shuang , Wang Zhe , Liu Baijun , Cao Chunlei , Zhang Huixuan 
Published: May 2014

ABSTRACTThe influence of an acid comonomer on the structural evolution and thermal behaviors of a polyacrylonitrile (PAN) terpolymer containing about 4.19 wt % methyl methacrylate and 0.98 wt % itaconic acid (IA) during a heating treatment were studied by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetry (TG) and compared with the PAN homopolymer. From the results of FTIR spectroscopy and DSC, we found that the presence of the IA comonomer promoted cyclization reactions at a faster rate and broadened the exothermic peak; this eased the concentration of heat release. By comparing the results of the TG data, we found that the presence of the IA comonomer promoted dehydrogenation reactions and the formation of a large quantity of better ladder structures. In additional, the better ladder structures that formed were easier to convert from ladder structures into graphitelike structures. The activation energy of random scissions at about 300°C was calculated by the Kissinger method. The results show that the presence of the IA comonomer inhibited the random scission reactions to some extent. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40834.
Fundamental influences on quasistatic and cyclic material behavior of short glass fiber reinforced polyamide illustrated on microscopic scale
Authors: Brunbauer Julia , Mösenbacher Andreas , Guster Christoph , Pinter Gerald 
Published: May 2014

ABSTRACTIn this work, the influences of fiber orientation and weld lines on the morphological structures and the mechanical behavior of polyamide 6.6 (PA6.6‐GF35) are investigated. In quasistatic and fatigue tests tensile and 3‐point‐bending loads are applied. Test temperatures vary between RT and 150°C. Two different specimen types are produced by using injection moulding process to create different fiber orientations as well as weld lines. Fiber orientations are determined using computer tomography. Scanning electron microscopy is used to investigate fracture surfaces of tested specimens. Results show that mechanical properties and morphological structures depend highly on fiber orientation and temperature. Transversely oriented fibers in weld lines result in brittle failure mechanisms and decreased mechanical properties. Different stress distributions in the specimens under tensile and flexural loads have influence on the material behavior as well. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40842.
Effect of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide on liquid oxygen compatibility of bisphenol a epoxy resin
Authors: Wu Zhanjun , Li Jialiang , Chen Yingpu , Wang Zhi , Li Shichao 
Published: May 2014

ABSTRACTIn this study, bisphenol A epoxy resin (DGEBA) was chemically modified by 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), and the molecular structure of the modified epoxy resin was characterized by Fourier transform infrared spectra. The effects of DOPO on liquid oxygen compatibility of DGEBA were calculated using mechanical impact method. The results indicated that epoxy resin (EP‐P1)/4,4‐diaminobisphenol sulfone (DDS) was compatible with liquid oxygen. When compared with EP/DDS, differential scanning calorimetry and thermogravimetry analyses showed that EP‐P1/DDS and EP‐P2/DDS had much higher glass transition temperatures and char yield. X‐ray photoelectron spectroscopic analysis suggested that phosphorus atoms on the surface of EP‐P1/DDS and EP‐P2/DDS could act in the solid phase to restrain the incompatible reaction, which was in accordance with the flame‐retardant mechanism of phosphorus‐containing compounds. The compatibility mechanism of EP‐P1/DDS was further proposed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 40848.
Effect of cross‐linked polycarboxylate‐type superplasticizers on the properties in cementitious system
Authors: Liu Hailu , Pang Hao , Ou Juhua , Zhang Lei , Dai Yongqiang , Liao Bing 
Published: May 2014

ABSTRACTFluidity and slump loss are main technical indicators for the quality of concrete. They are related to the dispersion of cement and hydration process, and are greatly affected by the structure of superplasticizers (SPs). For the purpose of obtaining SPs with excellent fluidity and slump retention, water‐soluble cross‐linked polycarboxylate ether copolymers (CLPCs) of acrylic acid and alkenyl alcohol type polyoxyethylene ether were synthesized. In order to gain full understanding of the effect of cross‐linked SPs on the properties in cementitious system, properties of the new SPs in cement paste were compared to those of traditional ones without cross‐linking agents. Mortar tests showed that CLPC performed obvious slow‐release function and kept about 10 mm higher than its initial paste flow after 150 min, while PC incurred loss of 15 mm after 150 min. Adsorption of CLPC on cement resulted in zeta potential being roughly the same as that in the case of PC, and enabled more effective slump retention to cement suspensions by rheological property tests. Ettringite peaks disappeared for CLPC on 1‐day curve and reappeared after 35 days, and the intensity of CH peaks for CLPC appeared weaker than Blank and PC after 1 day. The microstructure of CLPC after 1 day showed a very dense structure of smaller and thinner crystallites, which indicated that the early hydration was greatly delayed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40856.
Polyurethane coatings from liquefied wood containing remains of a copper‐, chromium‐, and boron‐based wood preservative
Authors: Hrastnik David , Humar Miha , Kričej Borut , Pavlič Matjaž , Pori Pavel , Cheumani Yona Arnaud M. , Petrič Marko 
Published: May 2014

ABSTRACTPreparation of polyurethane wood coatings based on copper‐, chromium‐, and boron (CCB) containing liquefied wood was performed, as an alternative way to manage postconsumed preservative‐contaminated wood. Additionally, we examined the possibility of improvement of selected properties of the liquefied wood‐based coatings by an addition of silica nanoparticles. The constituents of the CCB wood preservative do not exhibit an influence on a liquefaction process and on composition of the liquefied mixture. CCB also does not affect curing of the formulations containing liquefied wood and an isocyanate‐type hardener. Furthermore, influence of CCB on adhesion strength of liquefied wood‐based coatings on a wooden substrate, their hardness, and resistance to scratching and to water, acetone, and alcohol, is not exhibited. However, apart from these, from the applicative point of view, positive results, any improvement of the coating properties by the addition of silica nanoparticles is not shown. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40865.
Recent advances in engineering proteins for biocatalysis
Authors: Li Ye , Cirino Patrick C. 
Published: May 2014

ABSTRACTProtein engineers are increasingly able to rely on structure‐function insights, computational methods, and deeper understanding of natural biosynthesis processes, to streamline the design and applications of enzymes. This review highlights recent successes in applying new or improved protein engineering strategies toward the design of improved enzymes and enzymes with new activities. We focus on three approaches: structure‐guided protein design, computational design, and the use of novel scaffolding and compartmentalization techniques to improve performance of multienzyme systems. Examples described address problems relating to enzyme specificity, stability, and/or activity, or aim to balance sequential reactions and route intermediates by co‐localizing multiple enzymes. Specific applications include improving production of biofuels using enzymes with altered cofactor specificity, production of high‐value chiral compounds by enzymes with tailored substrate specificities, and accelerated cellulose degradation via multi‐enzyme scaffold assemblies. Collectively, these studies demonstrate a growing variety of computational and molecular biology tools. Continued advances on these fronts coupled with better mindfulness of how to apply proteins in unique ways offer exciting prospects for future protein engineering and biocatalysis research. Biotechnol. Bioeng. 2014;111: 1273–1287. © 2014 Wiley Periodicals, Inc.
Steroid treatment increases the recurrence of radiation‐induced organizing pneumonia after breast‐conserving therapy
Authors: Otani Keisuke , Nishiyama Kinji , Ito Yuri , Kawaguchi Yoshifumi , Inaji Hideo 
Published: May 2014

AbstractRadiation‐induced organizing pneumonia (RIOP) is an important complication of postoperative radiotherapy for breast cancer. Unfortunately, conventional corticosteroid therapy is frequently associated with relapses. The aim of this retrospective study was to evaluate the outcomes of steroid treatment in patients with RIOP. In total, 26 patients diagnosed with RIOP from among 2404 women who received radiotherapy after breast‐conserving surgery for breast cancer were included and classified into steroid (n = 7) and nonsteroid (n = 19) groups. Serum, sputum, and bronchoalveolar lavage composition; subjective symptoms (cough, fever, and dyspnea); migratory progression; and RIOP relapse were compared between the groups. Treatment type did not affect the duration of the subjective symptoms, which was 1.6 and 1.7 months for the steroid and nonsteroid groups, respectively. In contrast, RIOP relapse and new pulmonary lesions developed in five patients in the steroid group and only three patients in the nonsteroid group (P = 0.014). By assessing RIOP duration as the time to resolution of symptoms and discontinuation of therapy, the median duration of RIOP was significantly longer in the steroid (17.1 months) than that in the nonsteroid group (2.3 months, P = 0.005), primarily because of frequent relapses. After remission, persistent pulmonary dysfunction did not occur in the nonsteroid group. This single‐center retrospective study demonstrates that steroid therapy results in frequent relapses and significantly prolongs RIOP duration. Corticosteroid treatment is considered a critical factor in RIOP recurrence.
Role of latent membrane protein 1 in chronic active Epstein–Barr virus infection‐derived T/NK‐cell proliferation
Authors: Ito Takuto , Kawazu Hidetaka , Murata Takayuki , Iwata Seiko , Arakawa Saki , Sato Yoshitaka , Kuzushima Kiyotaka , Goshima Fumi , Kimura Hiroshi 
Published: May 2014

AbstractEpstein–Barr virus (EBV) predominantly infects B cells and causes B‐cell lymphomas, such as Burkitt lymphoma and Hodgkin lymphoma. However, it also infects other types of cells, including T and natural killer (NK) cells, and causes disorders, such as chronic active EBV infection (CAEBV) and T/NK‐cell lymphoma. The CAEBV is a lymphoproliferative disease with poor prognosis, where EBV‐positive T or NK cells grow rapidly, although the molecular mechanisms that cause the cell expansion still remain to be elucidated. EBV‐encoded latent membrane protein 1 (LMP1) is an oncogene that can transform some cell types, such as B cells and mouse fibroblasts, and thus may stimulate cell proliferation in CAEBV. Here, we examined the effect of LMP1 on EBV‐negative cells using the cells conditionally expressing LMP1, and on CAEBV‐derived EBV‐positive cells by inhibiting the function of LMP1 using a dominant negative form of LMP1. We demonstrated that LMP1 was responsible for the increased cell proliferation in the cell lines derived from CAEBV, while LMP1 did not give any proliferative advantage to the EBV‐negative cell line.
Single‐cell heterogeneity in suppression of PC12 differentiation by direct microinjection of a differentiation inhibitor, U0126
Authors: Chung Jihye , Miura Natsuko , Ito Akio , Sawada Munetaka , Nishikawa Shigemichi , Kuroda Kouichi , Ueda Mitsuyoshi 
Published: May 2014

AbstractPhenotypic and genomic heterogeneity among single cells in a cell population leads to inaccuracy and obscuration in research about mammalian cell differentiation. In order to address the problems regarding bulk analysis on heterogeneous cell populations, it is necessary to accurately regulate and analyze changes in differentiating cells at the single‐cell level. To investigate the single‐cell changes in PC12 neuronal differentiation that occur when inhibited by U0126, an inhibitor of mitogen‐activated protein kinase kinase (MEK), we directly injected the chemical into individual target cells and analyzed the outcomes (neurite outgrowth) at the single‐cell level. As a result, we could accurately regulate the quantity of U0126 being introduced into each target cell, which was previously not possible using the common method of simply adding the inhibitor to the culture medium. It was possible to analyze the inhibitive effect of U0126 even when the injected quantity was lower than the lower limit for inhibition when added to culture medium (0.1 μM, identical to 1.2 × 108 molecules per cell on dish). In particular, injection of 1.5 × 107 molecules into each cell resulted in a 59% decrease of the mean total neurite length. Time‐course analysis of neurite outgrowth at the single‐cell level using fluorescence staining method showed that the changes in neurite length of differentiating PC12 cells were not homogeneous, but were largely variable across individual target cells.
Nucleolar persistence during spermatogenesis of the genus Rhodnius (Hemiptera, Triatominae)
Authors: Alevi Kaio Cesar Chaboli , da Costa Castro Nayara Fernanda , Lima Anna Claudia Campaner , Ravazi Amanda , Morielle‐Souza Alessandra , de Oliveira Jader , da Rosa João Aristeu , de Azeredo Oliveira Maria Tercília Vilela 
Published: May 2014

AbstractThe Triatominae subfamily is comprised of 18 genera and six tribes. The tribe Rhodniini is comprised of two genera (Rhodnius and Psammolestes). Nucleolar persistence is defined by the presence of the nucleolus or nucleolar corpuscles during the meiotic metaphase. To date, this phenomenon has been described for 13 species of triatomine that are included in the genera Triatoma, Rhodnius, and Panstrongylus. Thus, because the phenomenon of nucleolar persistence has been described in only two species of the genus Rhodnius, we have analyzed the nucleolar behavior during spermatogenesis of eight species of the genus Rhodnius (R. colombiensis, R. montenegrensis, R. nasutus, R. neglectus, R. neivai, R. pictipes, R. prolixus, and R. robustus), with a focus on nucleolar persistence. By means of cytogenetic analysis with silver ions, nucleolar behavior during spermatogenesis is described in the eight species of Rhodnius analyzed. In all of them nucleolar behavior was similar and the phenomenon of nucleolar persistence was often observed. Therefore, we confirm nucleolar persistence as a peculiarity of the genus Rhodnius. However, it is emphasized that new cytogenetic analysis should be performed in the Triatominae subfamily, more specifically among the 15 genera that do not exhibit the nucleolar behavior described, in order to assess whether this phenomenon is truly a synapomorphy of these hematophagous insects.
Local and commissural IC neurons make axosomatic inputs on large GABAergic tectothalamic neurons
Authors: Ito Tetsufumi , Oliver Douglas L. 
Published: May 2014

ABSTRACTLarge GABAergic (LG) neurons are a distinct type of neuron in the inferior colliculus (IC) identified by their dense vesicular glutamate transporter 2 (VGLUT2)‐containing axosomatic synaptic terminals. Yet the sources of these terminals are unknown. Since IC glutamatergic neurons express VGLUT2, and IC neurons are known to have local collaterals, we tested the hypothesis that these excitatory, glutamatergic axosomatic inputs on LG neurons come from local axonal collaterals and commissural IC neurons. We injected a recombinant viral tracer into the IC which enabled Golgi‐like green fluorescent protein (GFP) labeling in both dendrites and axons. In all cases, we found terminals positive for both GFP and VGLUT2 (GFP+/VGLUT2+) that made axosomatic contacts on LG neurons. One to six axosomatic contacts were made on a single LG cell body by a single axonal branch. The GFP‐labeled neurons giving rise to the VGLUT2+ terminals on LG neurons were close by. The density of GFP+/VGLUT2+ terminals on the LG neurons was related to the number of nearby GFP‐labeled cells. On the contralateral side, a smaller number of LG neurons received axosomatic contacts from GFP+/VGLUT2+ terminals. In cases with a single GFP‐labeled glutamatergic neuron, the labeled axonal plexus was flat, oriented in parallel to the fibrodendritic laminae, and contacted 9‐30 LG cell bodies within the plexus. Our data demonstrated that within the IC microcircuitry there is a convergence of inputs from local IC excitatory neurons on LG cell bodies. This suggests that LG neurons are heavily influenced by the activity of the nearby laminar glutamatergic neurons in the IC. J. Comp. Neurol. 522:3539–3554, 2014. © 2014 Wiley Periodicals, Inc.