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https://www.readbyqxmd.com/read/28335550/preparation-of-biodegradable-and-elastic-poly-%C3%AE%C2%B5-caprolactone-co-lactide-copolymers-and-evaluation-as-a-localized-and-sustained-drug-delivery-carrier
#1
Ji Hoon Park, Bo Keun Lee, Seung Hun Park, Mal Geum Kim, Jin Woo Lee, Hye Yun Lee, Hai Bang Lee, Jae Ho Kim, Moon Suk Kim
To develop a biodegradable polymer possessing elasticity and flexibility, we synthesized MPEG-b-(PCL-co-PLA) copolymers (PCxLyA), which display specific rates of flexibility and elasticity. We synthesize the PCxLyA copolymers by ring-opening polymerization of ε-caprolactone and l-lactide. PCxLyA copolymers of various compositions were synthesized with 500,000 molecular weight. The PCxLyA copolymers mechanical properties were dependent on the mole ratio of the ε-caprolactone and l-lactide components. Cyclic tensile tests were carried out to investigate the resistance to creep of PCxLyA specimens after up to 20 deformation cycles to 50% elongation...
March 21, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28335427/laxative-effects-of-total-diterpenoids-extracted-from-the-roots-of-euphorbia-pekinensis-are-attributable-to-alterations-of-aquaporins-in-the-colon
#2
Kuilong Wang, Lian Liu, Jianyu Huang, Hongli Yu, Hao Wu, Yu Duan, Xiaobing Cui, Xingde Zhang, Liping Liu, Wei Wang
This study was designed to evaluate the toxic effects of total diterpenoids extracted from the roots of Euphorbia pekinensis (TDEP) on the mouse colon and to clarify the mechanism. Dried powdered roots of E. pekinensis were extracted with chloroform, and then the extract (6.7 g) was subjected to column chromatography and preparative TLC, giving TDEP. Using the HPLC-DAD method, the purity of TDEP was determined as 85.26%. Mice were orally administered with TDEP (3.942, 19.71 and 39.42 mg/kg), after which fecal water content and colon water content were examined...
March 14, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28335368/shape-evolution-of-hierarchical-w18o49-nanostructures-a-systematic-investigation-of-the-growth-mechanism-properties-and-morphology-dependent-photocatalytic-activities
#3
Guojuan Hai, Jianfeng Huang, Liyun Cao, Yanni Jie, Jiayin Li, Xing Wang
Hierarchical tungsten oxide assemblies such as spindle-like structures, flowers with sharp petals, nanowires and regular hexagonal structures are successfully synthesized via a solvothermal reduction method by simply adjusting the reaction conditions. On the basis of the experimental results, it is determined that the reaction time significantly influences the phase transition, microstructure and photocatalytic activity of the prepared samples. The possible mechanisms for the morphology evolution process have been systematically proposed...
December 14, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335332/micromechanical-properties-of-nanostructured-clay-oxide-multilayers-synthesized-by-layer-by-layer-self-assembly
#4
Dongwei Hou, Guoping Zhang, Rohit Raj Pant, Zhongxin Wei, Shuilong Shen
Clay-based nanostructured multilayers, such as clay-polymer multilayers and clay-oxide multilayers, have attracted growing attention owing to their remarkable mechanical properties and promising application in various fields. In this paper, synthesis of a new kind of nanostructured clay-oxide multilayers by layer-by-layer self-assembly was explored. Nano-mechanical characterization of 18 clay-based multilayer samples, prepared under as-deposited (i.e., air-dried) and annealing conditions at 400 °C/600 °C with different precursor cations and multilayer structure, were carried out using nanoindentation testing, atomic force microscopy (AFM), and X-ray diffraction (XRD)...
November 8, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335310/effect-of-continuous-multi-walled-carbon-nanotubes-on-thermal-and-mechanical-properties-of-flexible-composite-film
#5
Ji Eun Cha, Seong Yun Kim, Seung Hee Lee
To investigate the effect of continuous multi-walled carbon nanotubes (MWCNTs) on the thermal and mechanical properties of composites, we propose a fabrication method for a buckypaper-filled flexible composite film prepared by a two-step process involving buckypaper fabrication using vacuum filtration of MWCNTs, and composite film fabrication using the dipping method. The thermal conductivity and tensile strength of the composite film filled with the buckypaper exhibited improved results, respectively 76% and 275% greater than those of the individual MWCNT-filled composite film...
October 12, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335207/synergistic-effect-of-functionalized-nanokaolin-decorated-mwcnts-on-the-performance-of-cellulose-acetate-ca-membranes-spectacular
#6
Amina Afzal, Muhammad Shahid Rafique, Nadeem Iqbal, Asif Ali Qaiser, Abdul Waheed Anwar, Sadia Sagar Iqbal
In order to enhance salt rejection level and high pressure mechanical integrity, functionalized nanokaolin decorated multiwall carbon nanotubes (FNKM, 0-5 wt % loading) were incorporated into a cellulose acetate (CA) matrix using high temperature solution mixing methodology. Scanning electron microscopy (SEM), X-ray diffraction technique (XRD), thermo-gravimetric analyzer (TGA) and Fourier transform infrared spectrometer (FTIR) were used to characterize the prepared membranes. The obtained results revealed that with increasing FNKM concentration in the host polymeric matrix, composite membrane's structural, functional, thermal, water permeation/flux and salt rejection characteristics were also modified accordingly...
April 21, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335188/synthesis-of-lithium-metal-oxide-nanoparticles-by-induction-thermal-plasmas
#7
Manabu Tanaka, Takuya Kageyama, Hirotaka Sone, Shuhei Yoshida, Daisuke Okamoto, Takayuki Watanabe
Lithium metal oxide nanoparticles were synthesized by induction thermal plasma. Four different systems-Li-Mn, Li-Cr, Li-Co, and Li-Ni-were compared to understand formation mechanism of Li-Me oxide nanoparticles in thermal plasma process. Analyses of X-ray diffractometry and electron microscopy showed that Li-Me oxide nanoparticles were successfully synthesized in Li-Mn, Li-Cr, and Li-Co systems. Spinel structured LiMn₂O₄ with truncated octahedral shape was formed. Layer structured LiCrO₂ or LiCoO₂ nanoparticles with polyhedral shapes were also synthesized in Li-Cr or Li-Co systems...
April 6, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28334551/using-micro-patterned-surfaces-to-inhibit-settlement-and-biofilm-formation-by-bacillus-subtilis
#8
Siyuan Chang, Xiaodong Chen, Shuo Jiang, Jinchun Chen, Lin Shi
Biofilm is a biological complex caused by bacteria settlement to the substrates, their subsequent reproduction and secretion. This phenomena reduce heat transfer efficiency and cause significant losses in treated sewage heat recovering systems. This paper describes a physical approach to inhibit the bacteria settlement and biofilm formation by Bacillus subtilis, which is the dominant genera in the treated sewage. Here, the micro-patterned surfaces with different characteristics (stripe and cube) and dimensions (1 μm to 100 μm) were fabricated as surfaces of interest...
March 23, 2017: Canadian Journal of Microbiology
https://www.readbyqxmd.com/read/28334489/ce-iv-gd-iii-mixed-oxides-as-hosts-for-er-iii-based-upconversion-phosphors
#9
Cecilia Sorbello, Petra Gross, Cristian A Strassert, Matías Jobbágy, Beatriz C Barja
A family of Er(III) and Er(III) -Yb(III) based nanophosphors, hosted in monophasic oxidic Ce(IV) -Gd(III) binary solid solutions, was prepared. The samples were formulated with a constant Er(III) content as the activator, with the eventual addition of Yb(III) as a sensitizer. The amorphous Ce0.94-x Gdx Er0.06 (OH)CO3 ⋅H2 O and Ce0.94-x Gdx Er0.05 Yb0.01 (OH)CO3 ⋅H2 O precursors were prepared by following the urea method to obtain monodispersed spheres of tunable size ranging from 30 to 450 nm. After being decomposed at 1273 K under an atmosphere of air, the precursors of 200 nm in diameter evolved into monophasic polycrystalline particles preserving the parent shape and size...
March 23, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28334469/stereoisomerism-of-bis-sigma-zincane-complexes-evidence-for-an-intramolecular-pathway
#10
Mark Richard Crimmin, Olga Ekkert, Andrew White
The first bis(sigma-zincane) complexes, heterotrimetallic species [M(CO)4(2-HZnBDI)2], have been prepared (BDI = 2-{2,6-i-Pr2C6H3NCMe}2CH). For M = Cr a single stereoisomer is observed in solution and the solid-state. For M = Mo and W, cis and trans isomers where found to reversibly interconvert at 297 K. Despite the huge steric demands of the ligand on zinc, in all cases the cis isomer was found to be the most thermodynamically stable. The activation parameters for the isomerization when M = Mo are H‡ = 20...
March 23, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28333456/calixsmaragdyrin-a-versatile-ligand-for-coordination-complexes
#11
Tamal Chatterjee, Brian Molnar, G G Theophall, Way-Zen Lee, K V Lakshmi, Mangalampalli Ravikanth
The Ru(II) and BF2 complexes of calixsmaragdyrin were prepared under simple reaction conditions and characterized by HR-MS, 1D and 2D NMR spectroscopy, optical spectroscopy, and electrochemistry, and the structure of the Ru(II) complex of calixsmaragdyrin was elucidated by X-ray crystallography. The crystal structure of the Ru(II) complex revealed that the Ru(II) ion is hexacoordinate with the three pyrrole nitrogen ligands from the tripyrrin unit of the calixsmaragdyrin macrocycle, and the remaining coordination sites of Ru(II) ion were occupied by two carbonyl groups and one hydroxyl (-OH) group...
March 23, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28333431/ultrahigh-self-sensing-performance-of-geopolymer-nanocomposites-via-unique-interface-engineering
#12
Shuguang Bi, Ming Liu, Jingjing Shen, Xiao Matthew Hu, Liying Zhang
Monitoring and assessment of the health of a civil structural material are the critical requirements to ensure its safety and durability. In this work, a coating strategy on carbon nanotubes (CNTs) was employed for the dispersion of CNTs in geopolymer matrix. The geopolymer nanocomposites prepared exhibited ultrahigh self-sensing performance based on the unique behaviors of SiO2 coating on CNTs in the geopolymer matrix. The SiO2 layer on CNTs was partially or fully removed during the fabrication process to restore the conductive nature of CNTs, facilitating the dispersion of CNTs and forming well-connected 3D electrical conductive networks...
March 23, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28333379/motor-neurons
#13
Jorn Hounsgaard
Motor neurons translate synaptic input from widely distributed premotor networks into patterns of action potentials that orchestrate motor unit force and motor behavior. Intercalated between the CNS and muscles, motor neurons add to and adjust the final motor command. The identity and functional properties of this facility in the path from synaptic sites to the motor axon is reviewed with emphasis on voltage sensitive ion channels and regulatory metabotropic transmitter pathways. The catalog of the intrinsic response properties, their underlying mechanisms, and regulation obtained from motoneurons in in vitro preparations is far from complete...
March 16, 2017: Comprehensive Physiology
https://www.readbyqxmd.com/read/28333378/muscle-and-limb-mechanics
#14
George A Tsianos, Gerald E Loeb
Understanding of the musculoskeletal system has evolved from the collection of individual phenomena in highly selected experimental preparations under highly controlled and often unphysiological conditions. At the systems level, it is now possible to construct complete and reasonably accurate models of the kinetics and energetics of realistic muscles and to combine them to understand the dynamics of complete musculoskeletal systems performing natural behaviors. At the reductionist level, it is possible to relate most of the individual phenomena to the anatomical structures and biochemical processes that account for them...
March 16, 2017: Comprehensive Physiology
https://www.readbyqxmd.com/read/28333280/hcg-activates-the-erk1-2-mitogen-activated-protein-kinase-pathway-in-human-endometrial-stromal-cells-transiently-increasing-the-progesterone-receptor-and-regulating-genes-associated-with-endometrial-receptivity
#15
Alejandro Tapia-Pizarro, Sebastián Archiles, Felipe Argandoña, Cecilia Valencia, Keyla Zavaleta, María Cecilia Johnson, Reinaldo González-Ramos, Luigi Devoto
STUDY QUESTION: How does hCG signal in human endometrial stromal cells (ESCs) and what is its role in regulating ESC function? SUMMARY ANSWER: CG signaling in ESCs activates the extracellular signal-regulated protein kinases 1 and 2 (Erk1/2) pathway through exchange protein activated by cAMP (Epac) and transiently increases progesterone receptor (PR) transcript and protein expression and its transcriptional function. WHAT IS KNOWN ALREADY: hCG is one of the earliest embryo-derived secreted signals in the endometrium, which abundantly expresses LH/hCG receptors...
March 14, 2017: Molecular Human Reproduction
https://www.readbyqxmd.com/read/28332830/performance-and-mechanism-of-uranium-adsorption-from-seawater-to-polydopamine-inspired-sorbents
#16
Fengcheng Wu, Ning Pu, Gang Ye, Taoxiang Sun, Zhe Wang, Yang Song, Wenqing Wang, Xiaomei Huo, Yuexiang Lu, Jing Chen
Developing facile and robust technologies for effective enrichment of uranium from the seawater is of great significance for resource sustainability and environmental safety. By exploiting the mussel-inspired polydopamine (PDA) chemistry, diverse types of PDA-functionalized sorbents including magnetic nanoparticle (MNP), ordered mesoporous carbon (OMC) and glass fiber carpet (GFC) were synthesized. The PDA functional layers with abundant catechol and amine/imine groups provided an excellent platform for the binding to uranium...
March 23, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28332447/the-effect-of-native-silk-fibroin-powder-on-the-physical-properties-and-biocompatibility-of-biomedical-polyurethane-membrane
#17
Yan Zhuang, Qian Zhang, Jinqi Feng, Na Wang, Weilin Xu, Hongjun Yang
Naturally derived fibers such as silk fibroin can potentially enhance the biocompatibility of currently used biomaterials. This study investigated the physical properties of native silk fibroin powder and its effect on the biocompatibility of biomedical polyurethane. Native silk fibroin powder with an average diameter of 3 µm was prepared on a purpose-built machine. A simple method of phase inversion was used to produce biomedical polyurethane/native silk fibroin powder hybrid membranes at different blend ratios by immersing a biomedical polyurethane/native silk fibroin powder solution in deionized water at room temperature...
April 2017: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
https://www.readbyqxmd.com/read/28332343/bifunctional-cage-type-cubic-mesoporous-silica-sba-1-nanoparticles-for-selective-adsorption-of-dyes
#18
Chien-Hua Lin, Juti Rani Deka, Cheng-En Wu, Cheng-Hsun Tsai, Diganta Saikia, Yung-Chin Yang, Hsien-Ming Kao
Bifunctional SBA-1 mesoporous silica nanoparticles (MSNs) with carboxylic acid and amino groups (denoted as CNS-10-10) are successfully synthesized, characterized and employed as adsorbents for dye removal. The adsorbent CNS-10-10 shows high affinity towards cationic and anionic dyes in a wide pH range, and exhibits selective dye removal of a two dye mixture system of cationic methylene blue and anionic eosin Y. By changing the medium pH, the selectivity of adsorption behavior can be easily modulated. For comparison purposes, the counterparts, i...
March 23, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28332252/functional-organic-material-for-roxarsone-and-its-derivatives-recognition-via-molecular-imprinting
#19
Weigang Fan, Xuemin Zhang, Yagang Zhang, Penglei Wang, Letao Zhang, Zhaoming Yin, Jun Yao, Wei Xiang
Roxarsone, one of feed add drugs containing arsenic, has been most widely used in poultry and swine industry. Roxarsone discharged into the environment has caused serious pollution problem. Herein, a reusable functional material for selective recognition and adsorption of roxarsone and its derivatives were designed and synthesized. The interaction mechanism is based on acid-base interaction and surface molecular imprinting. Dual functionalized core-shell structure with silica gel as the core was prepared to use as carrier for surface molecularly imprinted polymers...
March 22, 2017: Journal of Molecular Recognition: JMR
https://www.readbyqxmd.com/read/28330759/amiodarone-reduces-depolarization-evoked-glutamate-release-from-hippocampual-synaptosomes
#20
Chia Yu Chang, Chi Feng Hung, Shu Kuei Huang, Jinn Rung Kuo, Su Jane Wang
Decreased brain glutamate level has emerged as a new therapeutic approach for epilepsy. This study investigated the effect and mechanism of amiodarone, an anti-arrhythmic drug with antiepileptic activity, on glutamate release in the rat hippocampus. In a synaptosomal preparation, amiodarone reduced 4-aminopyridine-evoked Ca(2+)-dependent glutamate release and cytosolic Ca(2+) concentration elevation. Amiodarone did not affect the 4-aminopyridine-evoked depolarization of the synaptosomal membrane potential or the Na(+) channel activator veratridine-evoked glutamate release, indicating that the amiodarone-mediated inhibition of glutamate release is not caused by a decrease in synaptosomal excitability...
March 8, 2017: Journal of Pharmacological Sciences
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