bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of bismuth oxide as a reinforcer on gamma shielding ability of unsaturated polyester based polymer composites
Authors: Ambika M. R. , Nagaiah N. , Suman S. K. 
Published: November 2016

ABSTRACTUnsaturated Polyester resin is reinforced with Bi2O3 up to 60% filler weight. The effect of bismuth oxide on gamma shielding ability of the composites is studied in terms of attenuation parameters using Ba‐133, Cs‐137, and Co‐60 gamma ray sources. The results reveal that, the shielding property of the composite material increases with increase in the filler concentration and decreases with energy. The HVL, TVL, and relaxation length of the composites are found to decrease with increase in the filler concentration. It is found that, the shielding ability of 60% filled polymer composite is comparable to that of barite at low energy. The above polymer composite performs well at all energies and can act as an excellent gamma radiation shield for low energies and also proved to be light weight when compared to the conventional shielding materials. Thus, the gamma shielding ability of the UP resin is enhanced due to the addition of Bi2O3. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44657.
Synthesis of a novel flame retardant containing phosphazene and triazine groups and its enhanced charring effect in poly(lactic acid) resin
Authors: Chen Yajun , Wang Wei , Liu Zhiqi , Yao Yuanyuan , Qian Lijun 
Published: November 2016

ABSTRACTA novel flame retardant heax‐[N,N′,N″‐tris‐(2‐amino‐ethyl)‐[1,3,5] triazine‐2,4,6‐triamine] cyclotriphosphazene (HTTCP) containing phosphazene and triazine groups was synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), solid‐state 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. HTTCP was applied to PLA matrix. The results of thermal gravimetric analysis (TGA), the limited oxygen index (LOI), and cone calorimeter test indicated that the HTTCP enhanced the thermal stability and flame retardant properties of PLA. When the mass fraction of HTTCP was 25 wt %, the PLA composite acquired a LOI value of 25.2% and the lower pk‐HRR at 290 kW/m2. The excellent flame retardancy of HTTCP was attributed to the group synergistic effect between phosphazene and triazine groups. However, when combined HTTCP with APP (the total amount remaining 25 wt %, the ratio of HTTP to APP are 1:1 and 1:2), high values of LOI (over 40%) and UL94 V‐0 rating without dripping reached simultaneously. Meanwhile, the heat release rate, total heat release and mass loss rate were all decreased dramatically. Scanning electron microscopy (SEM) demonstrated that HTTCP/APP system benefited to the formation of more intumescent, dense, compact char layer on the materials surface which could effectively prevent the underlying material from degradation during burning. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44660.
Degradation of radiation exposed polymethacrylamide (Rohacell® 31) foam used in composite hardware
Authors: Zaldivar R. J. , Labatete‐Goeppinger A. , Easton M. P. , Patel D. N. 
Published: November 2016

ABSTRACTRohacell® foam is a critical structural component used to fabricate composite hardware for space applications. The effect of radiation exposure on Rohacell® 31 HFHT has been evaluated to determine the degree of chemical and mechanical degradation that may occur in a space environment. A 60Co source was used for exposure levels ranging from 0 to 8 Mrad. Tensile tests showed significant decreases of 50% in tensile strength and 75% decreases in failure strain, after only a 4‐Mrad exposure. However, the rate of degradation sharply decreased with additional exposure since crosslink density was more affected during the early stages of radiation exposure. Size exclusion chromatography and multiangle light scattering of the extracted material also provided evidence showing an increase in the concentration of lower molecular weight (Mw) fragments after exposure. The average Mw of the extracted material dropped by two orders of magnitude from the control to the 5‐Mrad specimens, however changes in Mw between the 5‐ and 8‐Mrad specimens only varied by 30% similar in trend to mechanical property data. LS analysis showed a structural conformation change from a heavily branched network to a more linear conformation. Dynamic mechanical analysis exhibited increases in the peak height and breadth of the tan δ curve with radiation dose. These increases in damping are a result of chain scission which results in increased segmental motion caused by decreases in the degree of crosslinking within the polymer structure. Gas chromatography–mass spectrometry was used to probe the potential sites of radiation susceptibility within the PMI polymer structure and are discussed. The radiation susceptibility of this polymeric material should be properly evaluated when utilizing this material for space applications since end of life conditions may vary significantly from beginning of life mechanical and thermal behavior. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44670.
Green composites of poly(3‐hydroxybutyrate) and curaua fibers: Morphology and physical, thermal, and mechanical properties
Authors: Scalioni Lucas V. , Gutiérrez Miguel C. , Felisberti Maria I. 
Published: November 2016

ABSTRACTIn this article, we report the morphology and thermal, mechanical and physical properties of poly(3‐hydroxybutyrate) (PHB)/curaua composites containing triethyl citrate (TEC) as the plasticizer. The composites were prepared by mechanical mixing using pristine and chemically treated fibers (10 wt %) and TEC (30 wt %) and characterized by differential scanning calorimetry, dynamic mechanical analysis, X‐ray diffraction, small angle X‐ray scattering, polarized optical microscopy, scanning electron microscopy, tensile tests, impact resistance test, thermodilatometry, and thermal conductivity measurements. The curaua fibers acted as nucleating agent and strongly influenced the morphology of the crystalline phase of PHB, increasing the lamella thickness, decreasing the crystal size and inducing spherulite–axialite transition. These characteristics of the PHB crystalline phase determined all the properties of the composites. The tensile properties of the composites were comparable with those of neat PHB, while the impact resistance of composites was comparable with that of plasticized PHB. The higher heat capacity and thermal expansion coefficient and the lower thermal conductivity of the composites compared with neat PHB reflect the morphological changes in the PHB crystalline phase. The strategy of developing a green polymeric material from ecofriendly components exhibiting a good balance of properties by combining curaua fibers, TEC, and PHB was successful. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44676.
Thermal, mechanical, and acoustic properties of silica‐aerogel/UPVC composites
Authors: Eskandari Navid , Motahari Siamak , Atoufi Zhale , Hashemi Motlagh Ghodratollah , Najafi Mohammad 
Published: November 2016

ABSTRACTThe properties of silica‐aerogel/UPVC composites have been investigated with emphasis on sound and heat insulation. UPVC is a material of construction for window profiles and drainage pipes. Hydrophobic silica aerogels were synthesized using silicate sodium as a precursor through a two‐step sol–gel process. The physical and textural properties of the synthesized silica aerogels such as density, surface area, and particle size were analyzed using SEM and BET analysis. Then, the synthesized aerogels were mixed with Unplastisized Polyvinyl Chloride (UPVC) compound at five different weight ratios in an internal mixer to find out the effects of silica aerogels on the thermal, mechanical, and acoustical characteristics. The prepared UPVC/aerogel composites were characterized for tensile properties, impact strength, hardness, Vicat softening temperature, thermal conductivity, sound absorption, and sound transmission loss. The results revealed that adding silica aerogel in to the matrix of UPVC increases its hardness and softening temperature while decreases impact strength. The thermal conductivity of UPVC was decreased by up to 50% using silica aerogel. The sound absorption property of UPVC was increased up to three times by using silica aerogels due to its high porosity. Silica aerogel increased the maximum sound transmission loss of UPVC in the low frequency range. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44685.
Spectrofluorimetric determination of certain adrenergic agonist drugs in their pure forms and pharmaceutical formulations: Content uniformity test application
Authors: Badr El‐Din Khalid M. , Attia Tamer Z. 
Published: November 2016

AbstractA new, simple, sensitive and rapid spectrofluorimetric method has been developed for determination of certain adrenergic agonists such as isoxsuprine hydrochloride, ritodrine hydrochloride and etilefrine hydrochloride in their pure forms and pharmaceutical dosage forms. The method depends on micellar enhancement of the native fluorescence of investigated drugs by using 2% w/v sodium dodecyl sulfate (SDS) as an anionic surfactant. The enhanced fluorescence intensity of investigated drugs was measured at 305 nm after excitation at 278 nm. The interaction of studied drugs with SDS was studied, and the enhanced fluorescence intensity was exploited to develop an assay method for the determination of investigated drugs. The relative fluorescence intensity–concentration plots were rectilinear over the range 0.15–3.00 μg ml−1, with low quantification limits of 0.132, 0.123 and 0.118 μg mL−1 for isoxsuprine, ritodrine and etilefrine, respectively. The proposed method was successfully applied for determination of studied drugs in their pharmaceutical formulations. Moreover, the high sensitivity of the proposed method allows performing the content uniformity testing of the studied drugs in their tablets by using the official United States Pharmacopeia (USP) guidelines. Statistical comparisons of the results with those of the reported methods revealed excellent agreement and indicated no significant difference in accuracy and precision.
Sandwich–like Structure of Carbon Fluoride/Graphene Oxide/Polyacrylonitrile Cathode for Lithium and Sodium Batteries
Authors: Liu Wen , Zhan Bin‐Xin , Shi Bin , Li Yong , Guo Rui , Pei Hai‐Juan , Xie Jing‐Ying 
Published: November 2016

AbstractCarbon fluoride/graphene oxide/polyacrylonitrile (CFx/GO/PAN, denoted as CGP) electrodes are prepared for lithium primary and sodium secondary batteries. The introduction of GO sheets and PAN built a sandwich‐like structure. The rate performances of Li/CGP batteries verify that PAN and GO materials have negligible effects on the electrochemical properties of lithium primary batteries. In Na/CGP batteries, GO sheets have more defects to facilitate sodium ions transfer and offer more active sites for NaF deposition and decomposition. Meanwhile, the GO network coating of the CFx particles confines active fluorine during the cycles. Cubic and nanoscale discharge products of NaF form both on the surface of CFx particles and the GO sheets, respectively. Na/CGF batteries achieve an initial discharge capacity of 507.0 mAh g−1 and a voltage polarization of 0.75 V, except in the first cycle. These results demonstrate that CGP electrodes with a sandwich‐like structure have favorable electrochemical properties, resulting in the synergetic effect of GO sheets and PAN.
Structural Basis for the KlenTaq DNA Polymerase Catalysed Incorporation of Alkene‐ versus Alkyne‐Modified Nucleotides
Authors: Hottin Audrey , Betz Karin , Diederichs Kay , Marx Andreas 
Published: November 2016

AbstractEfficient incorporation of modified nucleotides by DNA polymerases is essential for many cutting‐edge biomolecular technologies. The present study compares the acceptance of either alkene‐ or alkyne‐modified nucleotides by KlenTaq DNA polymerase and provides structural insights into how 7‐deaza‐adenosine and deoxyuridine with attached alkene‐modifications are incorporated into the growing DNA strand. Thereby, we identified modified nucleotides that prove to be superior substrates for KlenTaq DNA polymerase compared with their natural analogues. The knowledge can be used to guide future design of functionalized nucleotide building blocks.
A convenient and validated enantiomer separation of chiral aliphatic amines as nitrobenzoxadiazole derivatives on polysaccharide‐derived chiral stationary phases under simultaneous ultraviolet and fluorescence detection
Authors: Adhikari Suraj , Kang Jong Seong , Lee Wonjae 
Published: November 2016

AbstractA convenient method using a fluorogenic agent, 4‐chloro‐7‐nitro‐1,2,3‐benzoxadiazole (NBD‐Cl), was developed for enantiomer separation of chiral aliphatic amines including amino alcohols by normal high‐performance liquid chromatography. The enantiomer separation of chiral aliphatic amines as NBD derivatives was performed on six covalently bonded and four coated‐type polysaccharide‐derived chiral stationary phases (CSPs) under simultaneous ultraviolet (UV) and fluorescence detection (FLD). Among the covalently bonded CSPs, Chiralpak IE showed the best enantiomer separation for most analytes. The other CSPs also showed good enantioselectivity except for Chiralpak IB. On the other hand, Chiralpak AD‐H and Amylose‐1 generally exhibited better enantiomer separation of NBD derivatized chiral amines among the coated CSPs. The developed analytical technique was also applied to determine the optical purity of commercially available (R)‐ and (S)‐leucinol; the impurity was found to be 0.06%. The developed method was validated and proved to be an accurate, precise, sensitive, and selective method suitable for separation of chiral aliphatic amines as NBD derivatives under simultaneous UV and FLD.
Differential in radiosensitizing potency of enantiomers of the fatty acid synthase inhibitor C75
Authors: Rae Colin , Babich John W. , Mairs Robert J. 
Published: November 2016

AbstractThe elevated activity of fatty acid synthase has been reported in a number of cancer types. Inhibition of this enzyme has been demonstrated to induce cancer cell death and reduce tumor growth. In addition, the fatty acid synthase inhibitor drug C75 has been reported to synergistically enhance the cancer‐killing ability of ionizing radiation. However, clinical use of C75 has been limited due to its producing weight loss, believed to be caused by alterations in the activity of carnitine palmitoyltransferase‐1. C75 is administered in the form of a racemic mixture of (−) and (+) enantiomers that may differ in their regulation of fatty acid synthase and carnitine palmitoyltransferase‐1. Therefore, we assessed the relative cancer‐killing potency of different enantiomeric forms of C75 in prostate cancer cells. These results suggest that (−)‐C75 is the more cytotoxic enantiomer and has greater radiosensitizing capacity than (+)‐C75. These observations will stimulate the development of fatty acid synthase inhibitors that are selective for cancer cells and enhance the tumor‐killing activity of ionizing radiation, while minimizing weight loss in cancer patients.
Monoamine Oxidase Inhibitory Activity: Methyl‐ versus Chlorochalcone Derivatives
Authors: Mathew Bijo , Uçar Gülberk , Mathew Githa Elizabeth , Mathew Sincy , Kalatharakkal Purapurath Praseedha , Moolayil Fasil , Mohan Smrithy , Varghese Gupta Sheeba 
Published: November 2016

AbstractNumerous studies have shown that chalcones are promising scaffolds for the development of new monoamine oxidase‐B (MAO‐B) inhibitors. As a continuation of our ongoing research into the development of reversible human MAO‐B (hMAO‐B) inhibitors, two series of twenty chalcones containing electron‐donating and electron‐withdrawing substituents were synthesized. All compounds were found to be competitive, selective, and reversible inhibitors of hMAO‐B except (2E)‐1‐(4‐methylphenyl)‐3‐(4‐nitrophenyl)prop‐2‐en‐1‐one (P7) and (2E)‐1‐(4‐chlorophenyl)‐3‐(4‐nitrophenyl)prop‐2‐en‐1‐one (P17), which were found to be selective inhibitors of hMAO‐A. The most potent hMAO‐B inhibitor, (2E)‐1‐(4‐chlorophenyl)‐3‐(4‐ethylphenyl)prop‐2‐en‐1‐one (P16), showed a Ki value of 0.11±0.01 μm. Molecular docking simulations were carried out to identify the hypothetical binding mode for the most potent compounds in the active sites of hMAO‐A and B. The ability of the compounds to cross the blood–brain barrier was assessed by parallel artificial membrane permeability assay (PAMPA). Additionally, the most potent hMAO‐B inhibitor P16 showed no toxicity in cultured hepatic cells at concentrations of 5 and 25 μm.
Salt Templating with Pore Padding: Hierarchical Pore Tailoring towards Functionalised Porous Carbons
Authors: Kumar K. Vasanth , Gadipelli Srinivas , Preuss Kathrin , Porwal Harshit , Zhao Tingting , Guo Zheng Xiao , Titirici Maria‐Magdalena 
Published: November 2016

AbstractWe propose a new synthetic route towards nanoporous functional carbon materials based on salt templating with pore‐padding approach (STPP). STPP relies on the use of a pore‐padding agent that undergoes an initial polymerisation/ condensation process prior to the formation of a solid carbon framework. The pore‐padding agent allows tailoring hierarchically the pore‐size distribution and controlling the amount of heteroatom (nitrogen in this case) functionalities as well as the type of nitrogen (graphitic, pyridinic, oxides of nitrogen) incorporated within the carbon framework in a single‐step‐process. Our newly developed STPP method offers a unique pathway and new design principle to create simultaneously high surface area, microporosity, functionality and pore hierarchy. The functional carbon materials produced by STPP showed a remarkable CO2/N2 selectivity. At 273 K, a carbon with only micropores offered an exceptionally high CO2 adsorption capacity whereas a carbon with only mesopores showed promising CO2‐philicity with high CO2/N2 selectivity in the range of 46–60 %, making them excellent candidates for CO2 capture from flue gas or for CO2 storage.
A general approach to testing for pleiotropy with rare and common variants
Authors: Lutz Sharon M. , Fingerlin Tasha E. , Hokanson John E. , Lange Christoph 
Published: November 2016

ABSTRACTThrough genome‐wide association studies, numerous genes have been shown to be associated with multiple phenotypes. To determine the overlap of genetic susceptibility of correlated phenotypes, one can apply multivariate regression or dimension reduction techniques, such as principal components analysis, and test for the association with the principal components of the phenotypes rather than the individual phenotypes. However, as these approaches test whether there is a genetic effect for at least one of the phenotypes, a significant test result does not necessarily imply pleiotropy. Recently, a method called Pleiotropy Estimation and Test Bootstrap (PET‐B) has been proposed to specifically test for pleiotropy (i.e., that two normally distributed phenotypes are both associated with the single nucleotide polymorphism of interest). Although the method examines the genetic overlap between the two quantitative phenotypes, the extension to binary phenotypes, three or more phenotypes, and rare variants is not straightforward. We provide two approaches to formally test this pleiotropic relationship in multiple scenarios. These approaches depend on permuting the phenotypes of interest and comparing the set of observed P‐values to the set of permuted P‐values in relation to the origin (e.g., a vector of zeros) either using the Hausdorff metric or a cutoff‐based approach. These approaches are appropriate for categorical and quantitative phenotypes, more than two phenotypes, common variants and rare variants. We evaluate these approaches under various simulation scenarios and apply them to the COPDGene study, a case‐control study of chronic obstructive pulmonary disease in current and former smokers.
Predictive factors and treatment outcome of laryngeal carcinoma recurrence
Authors: Haapaniemi Aaro , Väisänen Janne , Atula Timo , Alho Olli‐Pekka , Mäkitie Antti , Koivunen Petri 
Published: November 2016

AbstractBackgroundUp to 30% of patients with laryngeal squamous cell carcinoma (SCC) present with recurrence after treatment. We analyzed factors associated with the risk of cancer recurrence and prognosis after recurrence.MethodsA nationwide laryngeal SCC cohort from Finnish university hospitals during 2001 to 2005 with initial successful therapy (n = 316) was analyzed.ResultsLaryngeal SCC recurred in 22% of patients. The median time to recurrence was 9 months, with 90% occurring within 36 months after treatment. The World Health Organization (WHO) performance status >0, neck metastasis at presentation, and nonsurgical treatment were independent prognostic factors for recurrence. Patients with local recurrence had a 5‐year overall survival (OS) of 53% compared with 5% in patients with regional/distant recurrences. OS for glottic and nonglottic laryngeal SCC recurrence was 45% and 0%, respectively.ConclusionThe type of treatment affected the risk of recurrence in this retrospective series. Local recurrences carried a chance for successful salvage treatment. Routine follow‐up beyond 36 months remains controversial. © 2016 Wiley Periodicals, Inc. Head Neck 39: 555–563, 2017
Investigation of the effects of kisspeptin‐10 in methionine‐induced lipid peroxidation in testicle tissue of young rats
Authors: Akkaya Hatice , Eyuboglu Signem , Erkanlı Senturk Gozde , Yilmaz Bayram 
Published: November 2016

AbstractDisruption of the balance oxidants, antioxidants cause various pathophysiological conditions such as lipid peroxidation, protein degradation, or DNA damage. We have examined possible effects of kisspeptin‐10 on the structural damage produced by methionine‐induced lipid peroxidation in testicle tissue of young rats. Kisspeptin‐10 did not significantly affect spermatogenic cells in seminiferous tubules. Testosterone levels decreased in the methionine group as compared with the control group but without statistical significance. Luteinizing hormone levels decreased in the methionine group as compared with the control group (P < 0.001). Catalase enzyme activity increased in the kisspeptin‐10 group (P < 0.01) as compared with the other groups. Catalase mRNA expression was decreased in the methionine group as compared with the kisspeptin group (P < 0.001). Total superoxide dismutase enzyme activity and superoxide dismutase mRNA expression were increased in the kisspeptin group as compared with the methionine group (P < 0.05). In conclusion, kisspeptin treatment may protect the structure of spermatogenic cells against methionine‐induced damage.
Characterizing Graphs with Crossing Number at Least 2
Authors: Arroyo Alan , Richter R. Bruce 
Published: November 2016

AbstractOur main result includes the following, slightly surprising, fact: a 4‐connected nonplanar graph G has crossing number at least 2 if and only if, for every pair of edges having no common incident vertex, there are vertex‐disjoint cycles in G with one containing e and the other containing f.