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Philippe Charles Hiberty
The history of the two main theories of chemical bonding, Valence Bond and Molecular Orbital theories, with their respective localized and delocalized visions of the electron pairs, is briefly recalled with an emphasis on their equivalence at comparable computational levels. The delocalized/localized alternative also exists in the very framework of MO theory, since localized MOs can be obtained through unitary transformations which leave Slater determinants invariant. In particular, the use of hybrid orbitals in chemical interpretations is thus perfectly justified...
December 15, 2017: Angewandte Chemie
C W Extrand
The onset of drainage of liquids from fluid-handling components with a single, circular orifice was evaluated. A component was filled with water, ethylene glycol, or ethyl alcohol and then oriented vertically with its orifice facing downward. The lower end of the component was slowly tilted toward the horizon. No flow occurred until a critical angle of inclination was reached. The onset of drainage was successfully modeled as a balance between the hydrostatic pressure in the bulk liquid and the Laplace pressure of the air-liquid interface within the orifice...
December 15, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Michelle C Neary, Patrick J Quinlivan, Gerard Parkin
Zerovalent nickel compounds which feature 1,2-bis(diphenylphosphino)benzene (dppbz) were obtained via the reactivity of dppbz towards Ni(PMe3)4, which affords sequentially (dppbz)Ni(PMe3)2 and Ni(dppbz)2. Furthermore, the carbonyl derivatives (dppbz)Ni(PMe3)(CO) and (dppbz)Ni(CO)2 may be obtained via the reaction of CO with (dppbz)Ni(PMe3)2. Other methods for the synthesis of these carbonyl compounds include (i) the formation of (dppbz)Ni(CO)2 by the reaction of Ni(PPh3)2(CO)2 with dppbz and (ii) the formation of (dppbz)Ni(PMe3)(CO) by the reaction of (dppbz)Ni(CO)2 with PMe3...
December 15, 2017: Inorganic Chemistry
Xiaohong Jin, Yan Xu, Xuhong Yang, Xiuling Chen, Minghu Wu, Jianguo Guan, Lianshun Feng
A new class of ethylene/propylene-1H-1,2,3-triazole-4-methylene-tethered isatin-coumarin hybrids 8a-j, integrate three anti-tuberculosis pharmacophores coumarin, isatin and 1,2,3-triazole was designed and synthesized. These hybrids were assessed for their in vitro anti-TB activity against MTB H37Rv and MDR-TB, as well as anti-bacterial activity against Gram-positive and Gram-negative strains, and cytotoxicity in VERO cell line. The results showed that all hybrids with acceptable cytotoxicity (CC50: 64-512 μg/mL) exhibited weak to moderate anti-microbial activity...
December 14, 2017: Current Topics in Medicinal Chemistry
Chong Ding, Zhi-Hao Du, Sheng-Lin Li, Li-Ling Wu, Guang-Yan Yu
Adiponectin functions as a promoter of saliva secretion in rat submandibular gland via activation of adenosine monophosphate-activated protein kinase (AMPK) and increased paracellular permeability. Ca2+ mobilization is the primary signal for fluid secretion in salivary acinar cells. However, whether intracellular Ca2+ mobilization is involved in adiponectin-induced salivary secretion is unknown. Here, we found that full-length adiponectin (fAd) increased intracellular Ca2+ and saliva secretion in submandibular glands...
December 14, 2017: Journal of Molecular Histology
Eric Y Liu, Sukwon Jung, David A Weitz, Hyunmin Yi, Chang-Hyung Choi
Chemically functional hydrogel microspheres hold significant potential in a range of applications including biosensing, drug delivery, and tissue engineering due to their high degree of flexibility in imparting a range of functions. In this work, we present a simple, efficient, and high-throughput capillary microfluidic approach for controlled fabrication of monodisperse and chemically functional hydrogel microspheres via formation of double emulsion drops with an ultra-thin oil shell as a sacrificial template...
December 15, 2017: Lab on a Chip
Gaizhen Kuang, Zhiyun Zhang, Shi Liu, Dongfang Zhou, Xiaolan Lu, Xiabin Jing, Yubin Huang
The application of the biphasic release profile furnished by electrospun polyblend nanofibers for local cancer treatment was investigated. By adjusting the weight ratio of the hydrophilic polymer (poly(ethylene oxide), PEO) and hydrophobic polymer (poly(l-lactide), PLA), PEO10-PLA90 fibers with typical biphasic release kinetics were successfully prepared. Due to their unique release profile, PEO10-PLA90 fibers can quickly access the tumor site in vivo at a high drug content within 1 h and keep at a high level for longer than two weeks...
December 15, 2017: Biomaterials Science
Chen Lin, Margret Sauter
Rice is a semiaquatic plant that is well adapted to partial flooding. Rice stems develop adventitious root (AR) primordia at each node that slowly mature but emerge only when the plant gets flooded leading to the formation of a whole new secondary root system upon flooding. AR growth is induced by ethylene that accumulates in submerged plant tissues due to its lowered diffusion rate in water. Here we report that the architecture of the secondary root system in flooded rice plants is not only controlled by altered gas diffusion but also by gravity and light...
December 14, 2017: Plant Physiology
Tea Lenarčič, Isabell Albert, Hannah Böhm, Vesna Hodnik, Katja Pirc, Apolonija B Zavec, Marjetka Podobnik, David Pahovnik, Ema Žagar, Rory Pruitt, Peter Greimel, Akiko Yamaji-Hasegawa, Toshihide Kobayashi, Agnieszka Zienkiewicz, Jasmin Gömann, Jenny C Mortimer, Lin Fang, Adiilah Mamode-Cassim, Magali Deleu, Laurence Lins, Claudia Oecking, Ivo Feussner, Sébastien Mongrand, Gregor Anderluh, Thorsten Nürnberger
Necrosis and ethylene-inducing peptide 1-like (NLP) proteins constitute a superfamily of proteins produced by plant pathogenic bacteria, fungi, and oomycetes. Many NLPs are cytotoxins that facilitate microbial infection of eudicot, but not of monocot plants. Here, we report glycosylinositol phosphorylceramide (GIPC) sphingolipids as NLP toxin receptors. Plant mutants with altered GIPC composition were more resistant to NLP toxins. Binding studies and x-ray crystallography showed that NLPs form complexes with terminal monomeric hexose moieties of GIPCs that result in conformational changes within the toxin...
December 15, 2017: Science
Jefri Heyman, Balkan Canher, Anchal Bisht, Fien Christiaens, Lieven De Veylder
Plants react to wounding through the activation of both defense and repair pathways, but how these two responses are coordinated is unclear. Here, we put forward the hypothesis that diverse members of the subfamily X of the plant-specific ethylene response factor (ERF) transcription factors coordinate stress signaling with the activation of wound repair mechanisms. Moreover, we highlight the observation that tissue repair is strongly boosted through the formation of a heterodimeric protein complex that comprises ERF and transcription factors of the GRAS domain type...
December 14, 2017: Journal of Cell Science
James R Day, Anu David, Jiwon Kim, Evan A Farkash, Marilia Cascalho, Nikola Milašinović, Ariella Shikanov
Poly(ethylene glycol) (PEG) can be functionalized and modified with various moieties allowing for a multitude of cross-linking chemistries. Here, we investigate how vinyl sulfone, acrylate, and maleimide functional end groups affect hydrogel formation, physical properties, viability of encapsulated cells, post-polymerization modification, and inflammatory response of the host. We have shown that PEG-VS hydrogels, in the presence of a co-monomer, N-vinyl-2-pyrrolidone (NVP), form more efficiently than PEG-Ac and PEG-Mal hydrogels, resulting in superior physical properties after 6 minutes of ultraviolet light exposure...
December 11, 2017: Acta Biomaterialia
Xiaoming Luo, Maohua Chen, Zhoujiang Chen, Songzhi Xie, Nan He, Tao Wang, Xiaohong Li
Camptothecin (CPT)-containing promicelle polymers (PMCPT) based on 4-armed poly(ethylene glycol) (PEG) were developed previously to self-assemble into folate-targeted and glutathione (GSH)-sensitive micelles (MCPT). To address severe systemic toxicity and lack of tumor specificity implicated in the intravenous administration of MCPT, a micelle-generating depot has been developed by blend electrospinning of PEG-poly(lactide) (PELA) copolymers, PMCPT and polyethylene oxide (PEO). Upon implantation of the depot onto the tumor, PMCPT are sustainably released to spontaneously form MCPT on the tumor site...
December 11, 2017: Acta Biomaterialia
Xin Li, Ying He, Jie Yang, Yin-Hua Jia, Han-Lai Zeng
Abnormal environment weather can cause rice photoperiod-thermo-sensitive genic male sterile (PTGMS) lines fertile or partially fertile and thus cause the mixture of true hybrids with selfing seeds. Seedling-specific green-revertible albino leaf color mutant can be used to distinguish the real hybrids. Besides, it can also be used as an ideal material to research the development of chloroplast and biosynthesis of chlorophyll. The phenotype of leaf color mutants includes light green, yellowing, albino, green-revertible albino...
January 2018: Plant Science: An International Journal of Experimental Plant Biology
Esra Feyzioğlu Demir, Cansu Ilke Kuru, Murat Uygun, Deniz Aktaş Uygun, Sinan Akgöl
Herein we describe the synthesis of Concanavalin A-poly(2-hydroxyethyl methacrylate-ethylene dimethacrylate) hydrogel membranes (via photopolymerization technique) for antibody separation from aqueous solutions. Different characterization techniques including Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, Elemental Analysis and swelling tests revealed the highly rough morphology and spherical shape of the as-synthetized membranes. Attached amount of IMEO (salinization agent) onto polymeric structure and Con A binding capacity were found to be 10...
December 15, 2017: Journal of Biomaterials Science. Polymer Edition
Nan Hu, Jun Feng Yin, Ze Ji, Yidong Hong, Puyuan Wu, Baoxiang Bian, Ziyan Song, Rutian Li, Qin Liu, Fenglei Wu
BACKGROUND/AIMS: MicroRNA-21 is an oncogenic miR (oncomiR) frequently elevated in gastric cancer (GC). Overexpression of miR-21 decreases the sensitivity of GC cells to 5-fluorouridine (5-Fu) and trastuzumab, a humanized monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2). Receptor-mediated endocytosis plays a crucial role in the delivery of biotherapeutics including anti-miRNA oligonucleotides (AMOs). This study is a continuation of earlier findings involving poly(ε-caprolactone) (PCL)-poly (ethylene glycol) (PEG) nanoparticles (PEG-PCL NPs), which were coated with trastuzumab to target GC with HER2 receptor over-expression using anti-miRNA-21 (AMO-21) and 5-Fu...
December 12, 2017: Cellular Physiology and Biochemistry
Sara Babaei, Natalie Fekete, Corinne A Hoesli, Pierre-Luc Girard-Lauriault
The interactions between monocytes and biomaterials can potentially be modulated by controlling the chemical and structural surface properties of biomaterials. The objective of this study was to determine the effect of plasma-deposited functional organic coatings on monocyte adhesion and differentiation into macrophages. Organic coatings with varying oxygen and nitrogen concentration were prepared by low-pressure plasma co-polymerization of binary gas mixtures combining a hydrocarbon (butadiene/ethylene) and a heteroatom-containing gas (carbon dioxide/ammonia) to deposit either oxygen or nitrogen-containing coatings...
December 6, 2017: Colloids and Surfaces. B, Biointerfaces
Krzysztof Matyjaszewski, Liye Fu Fu, Alan Russell Russell, Alan E E Enciso
The first well-controlled aqueous atom transfer radical polymerization (ATRP) conducted in the open air was enabled by the continuous conversion of oxygen to carbon dioxide catalyzed by glucose oxidase (GOx), with glucose and sodium pyruvate as sequential sacrificial substrates. Controlled initiators for continuous activator regeneration (ICAR) ATRP of oligo(ethylene oxide) methyl ether methacrylate (OEOMA, Mn=500), yielded polymers with low dispersity (1.09≤Đ ≤1.29) and molecular weights (MW) close to theoretical with pyruvate...
December 14, 2017: Angewandte Chemie
Swarbhanu Sarkar, Nikunj Bhatt, Yeong Su Ha, Phuong Tu Huynh, Nisarg Soni, Woong Hee Lee, Yong Jin Lee, Jung Young Kim, Darpan N Pandya, Gwang Il An, Kyo Chul Lee, Yongmin Chang, Jeongsoo Yoo
Although the importance of bifunctional chelators (BFCs) is well recognized, the chemophysical parameters of chelators that govern the biological behavior of the corresponding bioconjugates have not been clearly elucidated. Here, five BFCs closely related in structure were conjugated with a cyclic RGD peptide and radiolabeled with Cu-64 ions. Various biophysical and chemical properties of the Cu(II) complexes were analyzed with the aim of identifying correlations between individual factors and the biological behavior of the conjugates...
December 14, 2017: Journal of Medicinal Chemistry
Heba Hosny, Nesrine El Gohary, Engy Saad, Heba Handoussa, Rasha M El Nashar
A molecularly imprinted polymer was synthesized for the purpose of sinapic acid isolation from Egyptian nutraceutical Botrytis italica, L. (broccoli) due to its prominent medicinal and wide pharmacological activities. A computational study was first developed to determine the optimal template to functional monomer molar ratio. Based on the computational results, five polymers were synthesized using a bulk polymerization method with sinapic acid as the template molecule. Evaluation of the synthesized polymers binding performance was carried out using batch rebinding assay, which revealed that the molecularly imprinted polymer of molar ratio (1:4:20), template to functional monomer (4-vinyl pyridine) to crosslinker (ethylene glycol dimethacrylate) was of optimum performance, thus, this polymer was applied for sinapic acid isolation from closely related analogues...
December 14, 2017: Journal of Separation Science
Donghoon Kim, Yongmoon Lee, Yonghwi Kim, Kathleen Mingle, Jochen Lauterbach, Douglas Blom, Thomas Vogt, Yongjae Lee
Ag-exchanged LSX, a large pore low silica analogue of faujasite, was prepared and post-synthetically modified using pressure and temperature in the presence of various pore-penetrating fluids. Using high-resolution synchrotron X-ray powder and single crystal diffraction we derive structural models of the as-prepared and post-synthetically modified Ag-LSX materials. In the as-prepared Ag-LSX model we located 96 Ag+ and 245 H2O molecules distributed over seven and five distinctive sites, respectively. At 1.4(1) GPa pressure and 150ºC in ethanol the number of Ag cations within the pores of Ag-LSX are reduced by ca...
December 14, 2017: Chemistry: a European Journal
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