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https://www.readbyqxmd.com/read/28822341/mullins-effect-in-polyethylene-and-its-dependency-on-crystal-content-a-network-alteration-model
#1
M Makki, G Ayoub, H Abdul-Hameed, F Zaïri, B Mansoor, M Naït-Abdelaziz, M Ouederni
This contribution is focused on the Mullins effect in polyethylene. An ultra-low-density polyethylene with 0.15 crystal content, a low-density polyethylene with 0.3 crystal content and a high-density polyethylene with 0.72 crystal content are subjected to cyclic stretching over a large strain range. Experimental observations are first reported to examine how the crystal content influences the Mullins effect in polyethylene. It is found that the cyclic stretching is characterized by a stress-softening, a hysteresis and a residual strain, whose amounts depends on the crystal content and the applied strain...
April 27, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28822320/bio-active-maneonenes-and-isomaneonene-from-the-red-alga-laurencia-obtusa
#2
Nahed O Bawakid, Walied M Alarif, Ali I Ismail, Mohamed E El-Hefnawy, Khalid O Al-Footy, Sultan S Al-Lihaibi
Three previously undescribed compounds, maneonenes and isomaneonene derivatives; in addition to five known compounds, two cuparene, one chamigrene, and two cis-maneonenes were isolated from the Red Sea red alga Laurencia obtusa. The chemical structures of all unknown metabolites were characterized employing spectroscopic methods and then were further confirmed by single crystal X-ray analysis. Jeddahenyne A has C-5-C-12 etheric linkage and C-13-C-14 carbon-carbon double bond; Jeddahenyne B has in addition to the aforementioned etheric linkage a C-13 carbonyl function and absence of halogenation, unusual features for the maneonenes while 12-debromo-12-methoxy isomaneonene A shows unrecorded methoxylation at C-12...
August 16, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28822287/blue-light-induced-free-radicals-from-riboflavin-in-degradation-of-crystal-violet-by-microbial-viability-evaluation
#3
Ji-Yuan Liang, Jeu-Ming P Yuann, Zong-Jhe Hsie, Shiuh-Tsuen Huang, Chiing-Chang Chen
Crystal violet (CV) is applied in daily use mainly as a commercial dye and antimicrobial agent. Waste water containing CV may affect aquatic ecosystems. Riboflavin, also known as vitamin B2, is non-toxic and an essential vitamin required for the functions of the human body. Riboflavin is photosensitive to UV and visible light in terms of generating reactive oxygen species. This study investigated the potential application of blue light on riboflavin, so as to come up with an effective way of degrading CV during its treatment...
August 12, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28822076/studies-of-the-benzopyran-class-of-selective-cox-2-inhibitors-using-3d-qsar-and-molecular-docking
#4
Dharmendra K Yadav, Saloni, Praveen Sharma, Sanjeev Misra, Harpreet Singh, Ricardo L Mancera, Kang Kim, Cheongyun Jang, Mi-Hyun Kim, Horacio Pérez-Sánchez, Eun Ha Choi, Surendra Kumar
The Gaussian-based 3D-QSAR studies for 58 selective COX-2 (cyclooxygenase-2) inhibitors belonging to benzopyran chemical class were performed. Partial least squares analysis produced statistically significant model with (R training(2)  = 0.866) and predictability (Q training(2)  = 0.66, Q test(2)  = 0.846). The 3D-QSAR model includes steric, electrostatic, hydrophobic, and hydrogen bond acceptor field indicators, whereas the potential field contributions indicate that the steric and hydrophobic features of the molecules play an important role in governing their biological activity...
August 18, 2017: Archives of Pharmacal Research
https://www.readbyqxmd.com/read/28822069/characterization-of-ofloxacin-interaction-with-mutated-a91v-quinolone-resistance-determining-region-of-dna-gyrase-in-mycobacterium-leprae-through-computational-simulation
#5
J Nisha, V Shanthi
Mycobacterium leprae, the causal agent of leprosy is non-cultivable in vitro. Thus, the assessment of antibiotic activity against Mycobacterium leprae depends primarily upon the time-consuming mouse footpad system. The GyrA protein of Mycobacterium leprae is the target of the antimycobacterial drug, Ofloxacin. In recent times, the GyrA mutation (A91V) has been found to be resistant to Ofloxacin. This phenomenon has necessitated the development of new, long-acting antimycobacterial compounds. The underlying mechanism of drug resistance is not completely known...
August 18, 2017: Cell Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28821862/water-soluble-epitaxial-nacl-thin-film-for-fabrication-of-flexible-devices
#6
Dong Kyu Lee, Sungjoo Kim, Sein Oh, Jae-Young Choi, Jong-Lam Lee, Hak Ki Yu
We studied growth mechanisms of water-soluble NaCl thin films on single crystal substrates. Epitaxial growth of NaCl(100) on Si(100) and domain-matched growth of NaCl(111) on c-sapphire were obtained at thicknesses below 100 nm even at room temperature from low lattice mismatches in both cases. NaCl thin film, which demonstrates high solubility selectivity for water, was successfully applied as a water-soluble sacrificial layer for fabrication of several functional materials, such as WO3 nano-helix and Sn doped In2O3 nano-branches...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821823/highly-efficient-up-conversion-luminescence-in-er-3-yb-3-co-doped-na5lu9f32-single-crystals-by-vertical-bridgman-method
#7
Shinan He, Haiping Xia, Jianli Zhang, Yongsheng Zhu, Baojiu Chen
Er(3+)/Yb(3+) co-doped Na5Lu9F32 single crystals with different concentrations of Yb(3+) ions were prepared to investigate their phase structure, up-conversion (UC) properties and mechanism of UC luminescence by Bridgman method. Under 980 nm near-infrared (NIR) excitation, three sharp UC emission bands topping at green ~525 nm, ~548 nm and red ~669 nm were obtained in Er(3+)/Yb(3+) doped Na5Lu9F32 single crystals which are attributing to the transitions of (2)H11/2 → (4)I15/2, (4)S3/2 → (4)I15/2 and (4)F9/2 → (4)I15/2, respectively...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821766/protein-composition-analysis-of-polyhedra-matrix-of-bombyx-mori-nucleopolyhedrovirus-bmnpv-showed-powerful-capacity-of-polyhedra-to-encapsulate-foreign-proteins
#8
Zhong-Jian Guo, Meng-Han Yu, Xian-Yun Dong, Wei-Li Wang, Ting Tian, Xian-Yin Yu, Xu-Dong Tang
Polyhedra can encapsulate other proteins and have potential applications as protein stabilizers. The extremely stable polyhedra matrix may provide a platform for future engineered micro-crystal devices. However, the protein composition of the polyhedra matrix remains largely unknown. In this study, the occlusion-derived virus (ODV)-removed BmNPV polyhedra matrix fraction was subjected to SDS-PAGE and then an LC-ESI-MS/MS analysis using a Thermo Scientific Q Exactive mass spectrometer. In total, 28 host and 91 viral proteins were identified...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821723/structural-and-developmental-expression-of-ss-riok-2-an-rio-protein-kinase-encoding-gene-of-strongyloides-stercoralis
#9
Wei-Qiang Lei, James B Lok, Wang Yuan, Yue-Zhou Zhang, Jonathan D Stoltzfus, Robin B Gasser, Si-Yuan He, Huan Zhou, Rui Zhou, Jun-Long Zhao, Min Hu
RIO kinases are essential atypical protein kinases in diverse prokaryotic and eukaryotic organisms, playing significant roles in yeast and humans. However, little is known about their functions in parasitic nematodes. In the present study, we have isolated and characterized the full-length cDNA, gDNA and a putative promoter of a RIOK-2 protein kinase (Ss-RIOK-2) encoding gene (Ss-riok-2) from Strongyloides stercoralis, a medically important parasitic nematode (Order Rhabditida). A three-dimensional structure (3D) model of Ss-RIOK-2 was generated using the Chaetomium thermophilum RIOK-2 protein kinase (Ct-RIOK-2) crystal structure 4GYG as a template...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821720/structural-basis-for-the-broad-substrate-specificity-of-the-human-tyrosylprotein-sulfotransferase-1
#10
Shinnosuke Tanaka, Toshiaki Nishiyori, Hidetaka Kojo, Reo Otsubo, Moe Tsuruta, Katsuhisa Kurogi, Ming-Cheh Liu, Masahito Suiko, Yoichi Sakakibara, Yoshimitsu Kakuta
Tyrosylprotein sulfotransferases (TPSTs) are enzymes that catalyze post-translational tyrosine sulfation of proteins. In humans, there are only two TPST isoforms, designated TPST1 and TPST2. In a previous study, we reported the crystal structure of TPST2, which revealed the catalytic mechanism of the tyrosine sulfation reaction. However, detailed molecular mechanisms underlying how TPSTs catalyse a variety of substrate proteins with different efficiencies and how TPSTs catalyze the sulfation of multiple tyrosine residues in a substrate protein remain unresolved...
August 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28821550/crystal-structure-of-the-tetr-family-repressor-alkx-from-dietzia-sp-dq12-45-1b-implicated-in-biodegradation-of-n-alkanes
#11
Jie-Liang Liang, Yuan Gao, Zheng He, Yong Nie, Meng Wang, Jing-Hong JiangYang, Xuejun C Zhang, Wen-Sheng Shu, Xiao-Lei Wu
n-Alkanes are ubiquitous in nature and are widely used by microorganisms as carbon sources. Alkane hydroxylation by alkane monooxygenases is a critical step in the aerobic biodegradation of n-alkanes, which plays important roles in natural alkane attenuation and is used in industrial and environmental applications. The alkane oxidation operon, alkW1-alkX, in an alkane-degrading strain Dietzia sp. DQ12-45-1b, is negatively auto-regulated by the TetR family repressor, AlkX, via a product positive feedback mechanism...
August 18, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28821431/bacillus-thuringiensis-cyt2aa2-binding-on-lipid-cholesterol-bilayer-depends-on-protein-concentration-and-time
#12
Sudarat Tharad, Alberto Moreno-Cencerrado, Öykü Üzülmez, Boonhiang Promdonkoy, Jose L Toca-Herrera
Bacillus thuringiensis is a bacterium known for its bioinsecticide properties. Besides Cry toxins, B. thuringiensis also produces cytolytic proteins (Cyt) that show toxicity against dipteran insect larvae. Two different models have been proposed in order to explain the interaction mechanism of the cytolytic protein Cyt2Aa2 on lipid membranes: pore-forming and detergent-like action. Here we report on the interaction of Cyt2Aa2 with lipid/cholesterol bilayers at early stage as a function of protein concentration...
August 15, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28821151/flexibility-of-backbone-fibrils-in-%C3%AE-chitin-crystals-with-different-degree-of-acetylation
#13
Zechuan Yu, Denvid Lau
Acetyl groups are backbone outreaches that enhance inter-fibril connection in chitin and chitosan fibril bundle. Removal of acetyl groups affects flexibility of chitosan fibril bundle, thereby affecting mechanical strength of chitosan-based products. Understandings of relationship between degree of acetylation and flexibility of chitin fibril bundle conduce to optimization of synthetic chitin materials. Here, the relationship is examined by performing molecular dynamics simulations. Coiling of chitin and chitosan fibril bundle with different degree of acetylation is observed and flexibility of fibrils is measured...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821149/solution-blow-spun-nanocomposites-of-poly-lactic-acid-cellulose-nanocrystals-from-eucalyptus-kraft-pulp
#14
Delne Domingos da Silva Parize, Juliano Elvis de Oliveira, Tina Williams, Delilah Wood, Roberto de Jesús Avena-Bustillos, Artur Piotr Klamczynski, Gregory Melvin Glenn, José Manoel Marconcini, Luiz Henrique Capparelli Mattoso
Cellulose nanocrystals (CNCs) were extracted from Eucalyptus kraft pulp by sulfuric acid hydrolysis, and esterified with maleic anhydride (CNCMA). The incorporation of sulfate ester groups on the cellulose surface resulted in higher stability of the nanoparticles in aqueous suspensions and lower thermal stability. Then, PLA/CNC and PLA/CNCMA nanocomposites were successfully obtained by solution blow spinning (SBS) using dimethyl carbonate (DMC) as solvent. CNC and CNCMA indicated to be acting both as nucleating agents or growth inhibitors of PLA crystal and tends to favor the formation of PLA crystals of higher stability...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821123/interfacial-modification-on-polyhydroxyalkanoates-starch-blend-by-grafting-%C3%A2-in-situ
#15
Pengwu Xu, Qingtao Zeng, Ying Cao, Piming Ma, Weifu Dong, Mingqing Chen
The interfacial adhesion between polyhydroxyalkanoates (PHAs) and native starch is poor. To improve the interfacial adhesion, PHAs were in-situ grafted onto starch using dicumyl peroxide (DCP) as a free radical initiator. The grafting reaction was carefully characterized and confirmed by gel analysis and Fourier transform infrared spectroscopy (FT-IR). The gel yield of the PHAs/starch/DCP blend increased with the DCP concentration up to 2wt%. Meanwhile, obvious plastic deformation (stretched fibrils) was observed at the interface in the PHAs/starch/DCP blend in comparison with complete interfacial debonding in the PHAs/starch physical blend...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821101/cholesteric-film-of-cu-ii-doped-cellulose-nanocrystals-for-colorimetric-sensing-of-ammonia-gas
#16
Shidong Dai, Nana Prempeh, Dagang Liu, Yimin Fan, Mingyue Gu, Yu Chang
With the increasing demand of environmental monitoring for toxic and odorous ammonia gas it is desired to develop specific green, cost-effective and in situ passive colorimetric alternatives to current complex instrumentations. In this work, we designed an ammonia gas sensor based on cholesteric liquid crystal films of copper(II)-doped cellulose nanocrystals (CNCCu(II)) whose structure, optical and sensing properties were investigated. The hybrid films using the low doping Cu(II) as a color-tuning agent inherited the chiral nematic signature and optical activity of CNCs, suggesting a strong chelation between copper ions and negatively charged CNCs...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821084/green-synthesis-of-oriented-xanthan-gum-graphene-oxide-hybrid-aerogels-for-water-purification
#17
Shunli Liu, Fang Yao, Olayinka Oderinde, Zhihong Zhang, Guodong Fu
Three-dimensional xanthan gum (XG)/graphene oxide (GO) hybrid aerogels were fabricated by ice crystal templating without using chemical modifiers. The hybrid aerogels were prepared by the stirring of xanthan gum-graphene oxide hybrid solution, followed by freezing at low temperature and finally by freeze-drying. The whole preparation could be completed within 12h without producing any contamination and thus considered a fast, simple, economical, and green method for aerogel fabrication. XG/GO hybrid aerogels possessed different hierarchical pore structures because of various freezing temperatures...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821040/characteristics-of-a-free-standing-film-from-banana-pseudostem-nanocellulose-generated-from-tempo-mediated-oxidation
#18
R H Fitri Faradilla, George Lee, Ji-Youn Arns, Justine Roberts, Penny Martens, Martina H Stenzel, Jayashree Arcot
Demand for bioplastic, especially for food packaging, increases as the consumers become more aware of the destructive effect of non-biodegradable plastics. Nanocellulose from banana pseudo-stem has great potential to be formed as a bioplastic. This study aimed to characterize the free-standing film produced from banana pseudo-stem nanocellulose that was prepared by TEMPO-mediated oxidation. The film was found containing calcium oxalate crystals, which most likely influenced the film transparency and possibly affected the contact angle and tensile strength...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821030/preparation-and-characterization-of-a-photocatalytic-antibacterial-material-graphene-oxide-tio2-bacterial-cellulose-nanocomposite
#19
Ling-Pu Liu, Xiao-Ning Yang, Li Ye, Dong-Dong Xue, Miao Liu, Shi-Ru Jia, Ying Hou, Li-Qiang Chu, Cheng Zhong
In this study, bacterial cellulose (BC) was used as a matrix to synthesize graphene oxide/Titanium dioxide (GOTiO2)-based hybrid materials. It was indicated by X-ray diffraction and selected area electron diffraction that the crystal structure of GOTiO2 was a mixed phase containing anatase and rutile. TiO2 nanoparticles were of 10-30nm diameters and densely anchored on graphene oxide sheets. Superior photocatalytic performance of the GOTiO2 was achieved under near UV excitation. The photocatalytic efficiency was optimized through controlling an appropriate calcined temperature...
October 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28821023/preparation-and-crystallization-behavior-of-poly-ethylene-2-5-furandicarboxylate-cellulose-composites-by-twin-screw-extrusion
#20
Amandine Codou, Nathanaël Guigo, Jesper Gabriël van Berkel, Ed de Jong, Nicolas Sbirrazzuoli
Poly(ethylene 2,5-furandicarboxylate) (PEF), an emerging biobased polyester, was compounded with cellulose via twin-screw extrusion. Different extrusion parameters such as mixing time, screw speed and temperature were employed. Composite thin films containing 1, 2 and 4% cellulose w/w were prepared and compared with neat PEF films. The morphology of PEF/cellulose composites was examined by scanning electron microscopy (SEM) and the molecular weight after extrusion was controlled by means of size exclusion chromatography (SEC)...
October 15, 2017: Carbohydrate Polymers
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