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https://www.readbyqxmd.com/read/28821151/flexibility-of-backbone-fibrils-in-%C3%AE-chitin-crystals-with-different-degree-of-acetylation
#1
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
#2
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
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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
https://www.readbyqxmd.com/read/28820940/polyoxometalate-cationic-cluster-and-%C3%AF-%C3%AE-cyclodextrin-from-primary-interactions-to-supramolecular-hybrid-materials
#9
Mhamad Aly Moussawi, Nathalie Leclerc-Laronze, Sébastien Floquet, Pavel A Abramov, Maxim Nailyevich Sokolov, Stephane Cordier, Anne Ponchel, Eric Monflier, Herve Bricout, David Landy, Mohamed Haouas, Jerome Marrot, Emmanuel Cadot
Herein, we report on a three-component supramolecular hybrid system built from specific recognition processes involving a Dawson type polyoxometalate [P2W18O62](6-,) a cationic electron-rich cluster {[Ta6Br12(H6O)6]@2CD}(2+) and γ-cyclodextrin. Investigations of such a class of materials have been conducted using bottom-up approach by studying the specific interactions between -CD and both types of inorganic units. Their ability to interact has been investigated in the solid state by single-crystal X-ray diffraction and in solution using multinuclear NMR methods (including DOSY, EXSY and COSY), ESI-mass and UV-vis spectroscopies, electrochemistry and ITC experiments...
August 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28820900/secy-seca-fusion-protein-retains-the-ability-to-mediate-protein-transport
#10
Yasunori Sugano, Arata Furukawa, Osamu Nureki, Yoshiki Tanaka, Tomoya Tsukazaki
In bacteria, the membrane protein complex SecY/E/G and SecA ATPase are essential for protein translocation. About 30% of newly synthesized proteins in the cytosol are targeted to and translocated across the cytoplasmic membrane by the Sec factors. Although a number of single-molecule analyses and structural studies, including the crystal structure of SecYEG complexed with SecA, have been published, the underlying molecular mechanisms and the functional oligomer states remain elusive. In this study, we constructed a fusion protein SecY-SecA, which induces the formation of the SecY-A/SecE/SecG complex (SecYAEG), to enable investigation of the molecular mechanisms by advanced single-molecule analyses...
2017: PloS One
https://www.readbyqxmd.com/read/28820602/intricate-resonant-raman-response-in-anisotropic-res2
#11
Amber McCreary, Jeffrey R Simpson, Yuanxi Wang, Daniel Rhodes, Kazunori Fujisawa, Luis Balicas, Madan Dubey, Vincent H Crespi, Mauricio Terrones, Angela R Hight Walker
The strong in-plane anisotropy of rhenium disulfide (ReS2) offers an additional physical parameter that can be tuned for advanced applications such as logic circuits, thin-film polarizers, and polarization-sensitive photodetectors. ReS2 also presents advantages for optoelectronics, as it is both a direct-gap semiconductor for few-layer thicknesses (unlike MoS2 or WS2) and stable in air (unlike black phosphorus). Raman spectroscopy is one of the most powerful characterization techniques to non-destructively and sensitively probe the fundamental photo-physics of a 2D material...
August 18, 2017: Nano Letters
https://www.readbyqxmd.com/read/28820596/processing-solvent-dependent-electronic-and-structural-properties-of-cesium-lead-triiodide-thin-films
#12
Alexandra J Ramadan, Luke A Rochford, Sarah Fearn, Henry J Snaith
Cesium lead triiodide (CsPbI3) is an attractive material for photovoltaic applications due to its appropriate band gap, strong optical absorption and high thermal stability. However, the perovskite phase suffers from moisture induced structural instability. Previous studies have utilized a range of solvent systems to establish the role of solvent choice in structural instabilities. Despite this, effects of different solvents on the electronic structure of this material have not been compared. We report substantial chemical and compositional differences in thin films of CsPbI3 prepared from a range of solvent systems...
August 18, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28820515/the-role-of-oncology-nurses-in-discussing-clinical-trials
#13
Susan A Flocke, Elizabeth Antognoli, Barbara J Daly, Brigid Jackson, Sarah E Fulton, Tasnuva M Liu, Jessica Surdam, Sharon Manne, Neal J Meropol
PURPOSE/OBJECTIVES: To describe oncology nurses' experiences discussing clinical trials with their patients, and to assess barriers to these discussions.
. RESEARCH APPROACH: A qualitative study designed to elicit narratives from oncology nurses. 
. SETTING: Community- and academic-based oncology clinics throughout the United States.
. PARTICIPANTS: 33 oncology nurses involved in direct patient care in community-based and large hospital-based settings...
September 1, 2017: Oncology Nursing Forum
https://www.readbyqxmd.com/read/28820490/the-potentiodynamic-bottom-up-growth-of-the-tin-oxide-nanostructured-layer-for-gas-analytical-multisensor-array-chips
#14
Fedor S Fedorov, Dmitry Podgainov, Alexey Varezhnikov, Andrey Lashkov, Michail Gorshenkov, Igor Burmistrov, Martin Sommer, Victor Sysoev
We report a deposition of the tin oxide/hydroxide nanostructured layer by the potentiodynamic method from acidic nitrate solutions directly over the substrate, equipped with multiple strip electrodes which is employed as a gas-analytical multisensor array chip. The electrochemical synthesis is set to favor the growth of the tin oxide/hydroxide phase, while the appearance of metallic Sn is suppressed by cycling. The as-synthesized tin oxide/hydroxide layer is characterized by mesoporous morphology with grains, 250-300 nm diameter, which are further crystallized into fine SnO₂ poly-nanocrystals following heating to 300 °C for 24 h just on the chip...
August 18, 2017: Sensors
https://www.readbyqxmd.com/read/28820466/a-dft-calculation-of-fluoride-doped-tio%C3%A2-nanotubes-for-detecting-sf%C3%A2-decomposition-components
#15
Xiaoxing Zhang, Jun Zhang, Xingchen Dong, Hao Cui
Gas insulated switchgear (GIS) plays an important role in the transmission and distribution of electric energy. Detecting and analyzing the decomposed components of SF₆ is one of the important methods to realize the on-line monitoring of GIS equipment. In this paper, considering the performance limits of intrinsic TiO₂ nanotube gas sensor, the adsorption process of H₂S, SO₂, SOF₂ and SO₂F₂ on fluoride-doped TiO₂ crystal plane was simulated by the first-principle method. The adsorption mechanism of these SF₆ decomposition components on fluorine-doped TiO₂ crystal plane was analyzed from a micro perspective...
August 18, 2017: Sensors
https://www.readbyqxmd.com/read/28820255/discovery-of-a-potent-inhibitor-class-with-high-selectivity-towards-clostridial-collagenases
#16
Esther Schönauer, Andreas Martin Kany, Jörg Haupenthal, Kristina Hüsecken, Isabel Josephin Hoppe, Katrin Voos, Samir Yahiaoui, Brigitta Elsässer, Christian Ducho, Hans Brandstetter, Rolf W Hartmann
Secreted virulence factors like bacterial collagenases are conceptually attractive targets for fighting microbial infections. However, previous attempts to develop potent compounds against these metalloproteases failed to achieve selectivity against human metalloproteases such as MMPs. Using an SPR-based screening complemented with enzyme inhibition assays, we discovered an N-aryl mercaptoacetamide-based inhibitor scaffold that showed submicromolar affinities towards collagenase H (ColH) from the human pathogen Clostridium histolyticum...
August 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28820205/a-comparative-study-of-c2h2-adsorption-properties-in-five-isomeric-copper-based-mofs-based-on-naphthalene-derived-diisophthalates
#17
Fengli Chen, Dongjie Bai, Donghao Jiang, Yao Wang, Yabing He
In this work, five positional isomeric ligands consisting of two peripheral isophthalate moieties attached to the central naphthyl core in different ways, namely, 5,5'-(naphthyl-1,3-diyl) diisophthalate (H4L1), 5,5'-(naphthyl-1,4-diyl) diisophthalate (H4L2), 5,5'-(naphthyl-1,5-diyl) diisophthalate (H4L3), 5,5'-(naphthyl-1,6-diyl) diisophthalate (H4L4) and 5,5'-(naphthyl-2,6-diyl) diisophthalate (H4L5), have been used to generate five copper-based MOF isomers. As revealed by single-crystal X-ray diffraction studies, they adopted two different types of topologies depending on the organic ligands: ssa topology for the MOFs ZJNU-71 and ZJNU-74 based on the ligands H4L1 and H4L4, respectively, and nbo topology for the MOFs ZJNU-72, ZJNU-73 and NOTT-103 derived from the ligands H4L2, H4L3 and H4L5, respectively...
August 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28819978/nanostructured-fibrous-membranes-with-rose-spike-like-architecture
#18
Amir Nasajpour, Serena Mandla, Sindu Shree, Ebrahim Mostafavi, Roholah Sharifi, Akbar Khalilpour, Saghi Saghazadeh, Shabir Hassan, Michael J Mitchell, Jeroen Leijten, Xu Hou, Alireza Moshaverinia, Nasim Annabi, Rainer Adelung, Yogendra Kumar Mishra, SuRyon Shin, Ali Tamayol, Ali Khademhosseini
Nanoparticles have been used for engineering composite materials to improve the intrinsic properties and/or add functionalities to pristine polymers. The majority of the studies have focused on the incorporation of spherical nanoparticles within the composite fibers. Herein, we incorporate anisotropic branched-shaped zinc oxide (ZnO) nanoparticles into fibrous scaffolds fabricated by electrospinning. The addition of the branched particles resulted in their protrusion from fibers, mimicking the architecture of a rose-stem...
August 18, 2017: Nano Letters
https://www.readbyqxmd.com/read/28819970/chemical-selectivity-at-grain-boundary-dislocations-in-monolayer-mo1-xwxs2-transition-metal-dichalcogenides
#19
Ziqian Wang, Yuhao Shen, Shoucong Ning, Yoshikazu Ito, Pan Liu, Zheng Tang, Takeshi Fujita, Akihiko Hirata, Mingwei Chen
Grain boundaries (GBs) are unavoidable crystal defects in polycrystalline materials and significantly influence their properties. However, the structure and chemistry of GBs in 2D transition metal dichalcogenide alloys have not been well established. Here we report significant chemical selectivity of transition metal atoms at GB dislocation cores in Mo1-xWxS2 monolayers. Different from classical elastic field-driven dislocation segregation in bulk crystals, the chemical selectivity in the 2D crystals originates prominently from variation of atomic coordination numbers at dislocation cores...
August 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28819697/mechanistic-understanding-of-crystal-violet-dye-sorption-by-woody-biochar-implications-for-wastewater-treatment
#20
Awanthi Wathukarage, Indika Herath, M C M Iqbal, Meththika Vithanage
Dye-based industries, particularly small and medium scale, discharge their effluents into waterways without treatment due to cost considerations. We investigated the use of biochars produced from the woody tree Gliricidia sepium at 300 °C (GBC300) and 500 °C (GBC500) in the laboratory and at 700 °C from a dendro bioenergy industry (GBC700), to evaluate their potential for sorption of crystal violet (CV) dye. Experiments were conducted to assess the effect of pH reaction time and CV loading on the adsorption process...
August 17, 2017: Environmental Geochemistry and Health
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