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https://www.readbyqxmd.com/read/28644006/structure-of-the-forkhead-domain-of-foxa2-bound-to-a-complete-dna-consensus-site
#1
Jun Li, Ana Carolina Dantas Machado, Ming Guo, Jared M Sagendorf, Zhan Zhou, Longying Jiang, Xiaojuan Chen, Daichao Wu, Lingzhi Qu, Zhu-Chu Chen, Lin Chen, Remo Rohs, Yongheng Chen
FOXA2, a member of the forkhead family of transcription factors, plays essential roles in liver development and bile acid homeostasis. In this study, we report a 2.8 Å co-crystal structure of the FOXA2 DNA-binding domain (FOXA2-DBD) bound to a DNA duplex containing a forkhead consensus binding site (GTAAACA). FOXA2-DBD adopts the canonical winged-helix fold, with helix H3 and wing 1 regions mainly mediating the DNA recognition. Although the wing 2 region was not defined in the structure, isothermal titration calorimetry (ITC) assays suggested that this region was required for optimal DNA binding...
June 23, 2017: Biochemistry
https://www.readbyqxmd.com/read/28643281/removal-of-the-emerging-contaminant-bisphenol-a-by-an-ureasil-peo-hybrid-membrane-experimental-study-and-molecular-dynamic-simulation
#2
Lilian K de Oliveira, André L A Moura, Valdir Barbosa, Renato L T Parreira, Rodrigo S Banegas, Giovanni F Caramori, Katia J Ciuffi, Eduardo F Molina
This work reports the use of a cross-linked ureasil-PEO hybrid matrix (designated PEO800) as an efficient adsorbent to retain the emerging contaminant bisphenol A (BPA) from an aqueous medium. The in-deep experimental and theoretical results provide information about the interactions between PEO800 and BPA. The in situ UV-vis spectroscopy data and the pseudo-first order, pseudo-second order, Elovich, and Morris-Webber intraparticle diffusion models allowed us to propose a three-step mechanism for the adsorption of BPA onto PEO800...
June 22, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28642044/crossregulation-between-the-insertion-of-hexadecylphosphocholine-miltefosine-into-lipid-membranes-and-their-rheology-and-lateral-structure
#3
Yenisleidy de Las Mercedes Zulueta Díaz, María Laura Fanani
Hexadecylphosphocholine (HePC, miltefosine) is an alkylphospholipid used clinically for the topical treatment of cancer and against leishmaniasis. The mechanism of action of HePC, not yet elucidated, involves its insertion into the plasma membrane, affecting lipid homeostasis. It has also been proposed that HePC directly affects lipid raft stability and function in cell membranes. The present work deals with two main questions in the understanding of the action of HePC: the bases for membrane selectivity and as a membrane perturbator agent...
June 19, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28640617/5-methylhydantoin-from-isolated-molecules-in-a-low-temperature-argon-matrix-to-solid-state-polymorphs-characterization
#4
Bernardo A Nogueira, Gulce O Ildiz, João Canotilho, M Ermelinda S Eusébio, Marta Sofia C Henriques, José A Paixão, Rui Fausto
The molecular structure, vibrational spectra and photochemistry of 5-methylhydantoin (C4H6N2O2; 5-MH) were studied by matrix isolation infrared spectroscopy and theoretical calculations at the DFT(B3LYP)/6-311++G(d,p) theory level. The Natural Bond Orbital (NBO) analysis approach was used to study in detail the electronic structure of the minimum energy structure of 5-MH, namely the specific characteristics of the σ and π electronic systems of the molecule, and the stabilizing orbital interactions. UV irradiation of 5-MH isolated in argon matrix resulted in its photofragmentation through a single photochemical pathway, yielding isocyanic acid, ethanimine and carbon monoxide, thus following a pattern already observed before for the parent hydantoin and 1-methylhydantoin molecules...
June 22, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28640593/dna-condensation-induced-by-a-star-shaped-hexameric-cationic-surfactant
#5
Yaxun Fan, Hua Wang, Chengqian He, Fulin Qiao, Shu Wang, Yilin Wang
The interactions between a star-shaped hexameric cationic quaternary ammonium surfactant PAHB and calf thymus DNA and induced DNA condensation were investigated by ζ-potential, dynamic light scattering, atomic force microscopy, isothermal titration calorimetry, ethidium bromide exclusion assay, circular dichroism and cytotoxicity assay. With the addition of PAHB, long extended DNA molecules exhibit successive conformational transitions from elongated coil to partially condensed cluster-like aggregate, globules-on-a-string structure, and then to fully condensed globule until the saturation point of interaction between PAHB and DNA, which is slightly above their charge neutralization point...
June 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28638778/synthesis-and-detonation-properties-of-5-amino-2-4-6-trinitro-1-3-dihydroxy-benzene
#6
Xingcheng Zhang, Hualin Xiong, Hongwei Yang, Guangbin Cheng
5-Amino-4,6-dinitro-1,3-dihydroxy-benzene (6) was synthesized through the ring-opening reaction of macrocyclic compound 4 with the aid of VNS (vicarious nucleophilic substitution of hydrogen) reaction conditions. The mechanism of ring opening of macrocyclic compound 4 was studied. 5-Amino-2,4,6-trinitro-1,3-dihydroxy-benzene (8) was obtained after the nitration of 6 in KNO3 and concentrated sulfuric acid. The thermal stability, sensitivity, and other detonation performances of 6 or 8 were compared to commercially used 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) or 1,3,5-trinitrotriazacyclohexane (RDX), respectively...
June 2017: ChemistryOpen
https://www.readbyqxmd.com/read/28637350/structural-peculiarities-of-ion-conductive-organic-inorganic-polymer-composites-based-on-aliphatic-epoxy-resin-and-salt-of-lithium-perchlorate
#7
Liubov Matkovska, Maksym Iurzhenko, Yevgen Mamunya, Igor Tkachenko, Valeriy Demchenko, Volodymyr Synyuk, Andriy Shadrin, Gisele Boiteux
The article is concerned with hybrid amorphous polymers synthesized basing on epoxy oligomer of diglycide aliphatic ester of polyethylene glycol that was cured by polyethylene polyamine and lithium perchlorate salt. Structural peculiarities of organic-inorganic polymer composites were studied by differential scanning calorimetry, wide-angle X-ray spectra, infrared spectroscopic, scanning electron microscopy, elemental analysis, and transmission and reflective optical microscopy. On the one hand, the results showed that the introduction of LiClO4 salt into epoxy polymer leads to formation of the coordinative metal-polymer complexes of donor-acceptor type between central Li(+) ion and ligand...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28636910/prp40-homolog-a-is-a-novel-centrin-target
#8
Adalberto Díaz Casas, Walter J Chazin, Belinda Pastrana-Ríos
Pre-mRNA processing protein 40 (Prp40) is a nuclear protein that has a role in pre-mRNA splicing. Prp40 possesses two leucine-rich nuclear export signals, but little is known about the function of Prp40 in the export process. Another protein that has a role in protein export is centrin, a member of the EF-hand superfamily of Ca(2+)-binding proteins. Prp40 was found to be a centrin target by yeast-two-hybrid screening using both Homo sapiens centrin 2 (Hscen2) and Chlamydomonas reinhardtii centrin (Crcen). We identified a centrin-binding site within H...
June 20, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28636317/downsizing-proto-oncogene-cfos-to-short-helix-constrained-peptides-that-bind-jun
#9
Daniel Baxter, Samuel R Perry, Timothy A Hill, W Mei Kok, Nathan R Zaccai, R Leo Brady, David P Fairlie, Jody M Mason
The oncogenic transcription factor activator protein-1 (AP-1) is a DNA-binding protein that assembles through dimerization of Fos and Jun protein subunits, their leucine-rich helical sequences entwining into a coiled-coil structure. This study reports on downsizing the proto-oncogene cFos protein (380 residues) to shorter peptides (37-25 residues) modified with helix-inducing constraints to enhance binding to Jun. A crystal structure is reported for a 37-residue Fos-derived peptide (FosW) bound to Jun. This guided iterative downsizing of FosW to shorter peptide sequences that were constrained into stable water-soluble α-helices by connecting amino acid side chains to form cyclic pentapeptide components...
June 21, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28636267/strontium-releasing-fluorapatite-glass-ceramics-crystallization-behavior-microstructure-and-solubility
#10
Isabelle Denry, Ourania-Menti Goudouri, Jeffrey D Harless, E M Hubbard, Julie A Holloway
The purpose of this work was to investigate the effect of strontium partial replacement for calcium on the crystallization behavior, microstructure and solubility of fluorapatite glass-ceramics. Four glass compositions were prepared with increasing amounts of strontium partially replacing calcium. The crystallization behavior was analyzed by differential scanning calorimetry and X-ray diffraction (XRD). The microstructure was investigated by scanning electron microscopy. The chemical solubility was quantified according to ISO standard 10993-14...
June 21, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/28636013/new-insights-into-the-solubility-of-graphene-oxide-in-water-and-alcohols
#11
Vadim V Neklyudov, Nail R Khafizov, Igor A Sedov, Ayrat M Dimiev
One of the main advantages of graphene oxide (GO) over its non-oxidized counterpart is its ability to form stable solutions in water and some organic solvents. At the same time, the nature of GO solutions is not completely understood; the existing data are scarce and controversial. Here, we demonstrate that the solubility of GO, and the stability of the as-formed solutions depend not just on the solute and solvent cohesion parameters, as commonly believed, but mostly on the chemical interactions at the GO/solvent interface...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28635272/efficient-flame-retardant-and-smoke-suppression-properties-of-mg-al-layered-double-hydroxide-nanostructures-on-wood-substrate
#12
Bingtuo Guo, Yongzhuang Liu, Qi Zhang, Fengqiang Wang, Qingwen Wang, Yixing Liu, Jian Li, Haipeng Yu
Improving the flame retardancy of wood is an imperative, yet highly challenging step in the application of wood in densely populated spaces. In this study, Mg-Al layered double hydroxide (LDH) coating was successfully fabricated on a wood substrate to confer flame-retardant and smoke-suppression properties. The chemical compositions and bonding states characterized by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed the coating constituents of Mg-Al LDH. The coating evenly covered the sample wood surfaces and provided both mechanical enhancement and flame-retardancy effects...
June 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28633826/optimization-and-characterization-of-ultrasound-assisted-preparation-of-curcumin-loaded-solid-lipid-nanoparticles-application-of-central-composite-design-thermal-analysis-and-x-ray-diffraction-techniques
#13
Elham Sadati Behbahani, Mehrorang Ghaedi, Mohammadreza Abbaspour, Kobra Rostamizadeh
This study is devoted to preparation of novel solid lipid nanoparticles (SLNs) for the encapsulation of curcumin which is produced by micro-emulsion and ultrasonication using stearic acid and tripalmitin as solid lipids, tween80 and span80 as surfactants. The relation between particle size and entrapment efficiency of the produced SLNs was operated by central composite design (CCD) under response likes surface method (RSM). The variables including the ratio of lipids (X1), the ratio of surfactants (X2), drug/lipid ratio (X3), time of sonication (X4) and time of homogenization (X5)...
September 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28633822/effects-of-pulsed-ultrasound-on-rheological-and-structural-properties-of-chicken-myofibrillar-protein
#14
Jing-Yu Wang, Yu-Ling Yang, Xiao-Zhi Tang, Wen-Xi Ni, Lei Zhou
The effects of pulsed ultrasound (PUS) (power: 240w) with varying time (0, 3, 6, 9, 12 and 15min) on rheological and structural properties of chicken myofibrillar protein (CMP) were examined. PUS treatment significantly caused a decrease in the viscosity coefficients (k) but an increase in the flow index (n) value of CMP solutions within short time (0-6min), while had no significant effect for longer time (9-15min). Besides, at 6min, the solubility and microstructure of CMP samples were optimum. The primary structure of CMP was not altered by PUS treatment...
September 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28633495/estradiol-protects-against-cardio-respiratory-dysfunctions-and-oxidative-stress-in-intermittent-hypoxia
#15
Sofien Laouafa, Alexandra Ribon-Demars, François Marcouiller, Damien Roussel, Aida Bairam, Vincent Pialoux, Vincent Joseph
Study Objectives: We tested the hypothesis that estradiol (E2) protects against cardio-respiratory disorders and oxidative stress induced by chronic intermittent hypoxia (CIH) in adult female rats. Methods: Sprague-Dawley female rats (230-250g) were ovariectomized (OVX) and implanted with osmotic pumps delivering vehicle (Veh) or E2 (0.5 mg/kg/day). After 14 days of recovery, the rats were exposed to chronic CIH (21%-10% O2 - 8 hours/day - 10 cycles/hour) or room air (RA)...
June 19, 2017: Sleep
https://www.readbyqxmd.com/read/28631808/fabrication-of-%C3%AE-cyclodextrin-mediated-single-bimolecular-inclusion-complex-characterization-molecular-docking-in-vitro-release-and-bioavailability-studies-for-gefitinib-and-simvastatin-conjugate
#16
Souvik Basak, Sandip Mondal, Suddhasattya Dey, Plaban Bhattacharya, Achintya Saha, Vinay Deep Punetha, Ali Abbas, Nanda Gopal Sahoo
OBJECTIVES: Introduction of multiple molecules in a single inclusion complex, albeit cheaper, lacks conclusive attempts in earlier drug delivery reports. This manuscript emphasizes simultaneous incorporation of two anticancer drugs, gefitinib (G) and simvastatin (S), in a single molecule of β-cyclodextrin for the first time to achieve effective drug delivery. METHODS: The inclusion complex (GSBCD) was prepared by cosolvent evaporation technique using β-cyclodextrin (BCD) as carrier...
June 20, 2017: Journal of Pharmacy and Pharmacology
https://www.readbyqxmd.com/read/28629216/amphiphilic-antifogging-anti-icing-coatings-containing-poss-pdmaema-b-psbma
#17
Chuan Li, Xiaohui Li, Chao Tao, Lixia Ren, Yunhui Zhao, Shan Bai, Xiaoyan Yuan
Highly transparent antifogging/anti-icing coatings were developed from amphiphilic block copolymers of polyhedral oligomeric silsesquioxane-poly[2-(dimethylamino)ethyl methacrylate]-block-poly(sulfobetaine methacrylate) (POSS-PDMAEMA-b-PSBMA) with a small amount of ethylene glycol dimethacrylate (EGDMA) via UV-curing. The excellent antifogging properties of the prepared coatings were originated from the hygroscopicity of both PDMAEMA and PSBMA blocks in the semi-interpenetrating polymer network (SIPN) with polymerization of EGDMA, and the hydrophobic POSS aggregated on the surface...
June 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28629215/unusual-interfacial-freezing-phenomena-in-hexacontane-silica-composites
#18
Xia Gao, Yunlan Su, Weiwei Zhao, Qingyun Qian, Xin Chen, Robert Wittenbrink, Dujin Wang
The crystallization behaviors of n-hexacontane (C60H122)/Stöber silica (SiO2) composites with various compositions were investigated by a combination of differential scanning calorimetry (DSC), solid-state (13)C nuclear magnetic resonance (solid-state (13)C NMR) and Proton NMR relaxation experiments. By means of DSC, C60H122 molecules in C60H122/silica composites were observed to be involved in the interfacial freezing not present in the free bulk C60H122. The orientation of C60H122 molecules, being preferentially normal to silica surface, was confirmed by grazing incidence X-ray diffraction experiments on thin n-hexacontane film adsorbed on the silicon wafer with a native SiO2 layer...
June 19, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28629099/instrumental-methods-and-techniques-for-structural-and-physicochemical-characterization-of-biomaterials-and-bone-tissue-a-review
#19
REVIEW
Žarko Mitić, Aleksandra Stolić, Sanja Stojanović, Stevo Najman, Nenad Ignjatović, Goran Nikolić, Miroslav Trajanović
A review of recent advances in instrumental methods and techniques for structural and physicochemical characterization of biomaterials and bone tissue is presented in this paper. In recent years, biomaterials attracted great attention primarily because of the wide range of biomedical applications. This paper focuses on the practical aspects of instrumental methods and techniques that were most often applied (X-ray methods, vibrational spectroscopy (IR and Raman), magnetic-resonance spectroscopy (NMR and ESR), mass spectrometry (MS), atomic absorption spectrometry (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES), thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM)) in the structural investigation and physicochemical characterization of biomaterials and bone tissue...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28629087/a-novel-candidate-for-wound-dressing-transparent-porous-maghemite-cellulose-nanocomposite-membranes-with-controlled-release-of-doxorubicin-from-a-simple-approach
#20
Hao Zhang, Xiaogang Luo, Hu Tang, Mingming Zheng, Fenghong Huang
The aim of this study is to develop transparent maghemite/cellulose nanocomposite membranes with high porosity, high adsorption capacity and controlled release of doxorubicin to be used as a candidate for wound dressing. The membranes were fabricated by a tape casting method through blending a homogeneous dispersion of citrate coated maghemite nanoparticles and cellulose in the NaOH/urea aqueous solution system. The prepared membranes were characterized by Light transmittance measurements, Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray Diffractometry (XRD), Differential scanning calorimetry (DSC), Tensile tests and Vibrating sample magnetometer (VSM)...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
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