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Electron microscopy

Mahsa Mazloomi-Rezvani, Mehdi Salami-Kalajahi, Hossein Roghani-Mamaqani
Different core-shell nanoparticles with Au as core and stimuli-responsive polymers such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(N-isopropylacrylamide) (PNIPAAm), poly(N,N'-methylenebis(acrylamide)) (PMBA), poly(2-hydroxyethyl methacrylate) (PHEMA) and poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) as shells were fabricated via inverse emulsion polymerization. Dynamic light scattering (DLS) was used to investigate particles sizes and particle size distributions and transmission electron microscopy (TEM) was applied to observe the core-shell structure of Au-polymer nanoparticles...
March 13, 2018: Colloids and Surfaces. B, Biointerfaces
Min Cheng, Guangming Zeng, Danlian Huang, Cui Lai, Yang Liu, Chen Zhang, Jia Wan, Liang Hu, Chengyun Zhou, Weiping Xiong
The presence of antibiotics in aquatic environments has attracted global concern. Fenton process is an attractive yet challenging method for antibiotics degradation, especially when such a reaction can be conducted at neutral pH values. In this study, a novel composite Fe/Co catalyst was synthesized via the modification of steel converter slag (SCS) by salicylic acid-methanol (SAM) and cobalt nitrate (Co(NO3 )2 ). The catalysts were characterized by N2 -Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS)...
March 10, 2018: Water Research
Xiangzhi Meng, Thomas Kaever, Bo Yan, Paula Traktman, Dirk M Zajonc, Bjoern Peters, Shane Crotty, Yan Xiang
Vaccinia virus (VACV) A14 is a major envelope protein and a dominant antibody target in the smallpox vaccine. However, the role of anti-A14 antibodies in immunity against orthopoxviruses is unclear. Here, we characterized 22 A14 monoclonal antibodies (mAb) from two mice immunized with VACV. Epitope mapping showed that 21 mAbs targeted the C-terminal hydrophilic region, while one mAb recognized the middle region predicted to be across the viral envelope from the C-terminus. However, none of the mAbs bound to virions in studies with electron microscopy...
March 17, 2018: Virology
Joseph Houston Dycus, Kelsey J Mirrielees, Everett D Grimley, Ronny Kirste, Seiji Mita, Zlatko Sitar, Ramon Collazo, Doug Irving, James M LeBeau
When pristine material surfaces are exposed to air, highly reactive broken bonds can promote the formation of surface oxides with structures and properties differing greatly from bulk. Determination of the oxide structure, however, is often elusive through the use of indirect diffraction methods or techniques that probe only the outer most layer. As a result, surface oxides forming on widely used materials, such as group III-nitrides, have not been unambiguously resolved, even though critical properties can depend sensitively on their presence...
March 20, 2018: ACS Applied Materials & Interfaces
Yuejiao Yang, Jie Chen, Walter Bonani, Bin Chen, Sabrina Eccheli, Devid Maniglio, Claudio Migliaresi, Antonella Motta
Silk fibroin has acquired increasing interest in the last years for application in medicine and namely in tissue engineering. Several methods have been developed to process fibroin and for the fabrication of nets, sponges, films and gels. This paper deals with the fabrication and characterization of fibroin hydrogels obtained by using sodium oleate as gelation agent. Gels have been prepared by mixing Silk fibroin (SF) and Sodium oleate (SO) water solutions in different concentrations, and a quite wide frame of compositions have been explored...
March 20, 2018: Journal of Biomaterials Science. Polymer Edition
Simon Drescher, Christian Otto, Sindy Müller, Vasil M Garamus, Christopher J Garvey, Susanne Grünert, Anke Lischka, Annette Meister, Alfred Blume, Bodo Dobner
In the present work, we describe the synthesis and the temperature-dependent aggregation behavior of a new class of asymmetrical glycerol diether bolalipid. These bolalipids are composed of a membrane-spanning alkyl chain with 32 carbon atoms (C32) in the sn-3 position, a methyl-branched C16 alkyl chain in the sn-2 position, and a zwitterionic phosphocholine headgroup in the sn-1 position of a glycerol moiety. The long C32 alkyl chain is terminated either by a second phos-phocholine (PC-Gly(2C16Me)C32-PC) or by a phosphodimethylethanolamine headgroup (PC-Gly(2C16Me)C32-Me2PE)...
March 20, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Fen Qiu, René H J Vervuurt, Marcel A Verheijen, Edmond W Zaia, Erin B Creel, Youngsang Kim, Jeffrey J Urban, Ageeth A Bol
Supported catalysts are widely used in industry and can be optimized by tuning the composition, chemical structure, and interface of the nanoparticle catalyst and oxide support. Here we firstly combine a bottom up colloidal synthesis method with a top down atomic layer deposition (ALD) process to achieve a raspberry-like Pt-decorated Fe3O4 (Fe3O4-Pt) nanoparticle superlattices. This nanocomposite ensures the precision of the catalyst/support interface, improving the catalytic efficiency of the Fe3O4-Pt nanocomposite system...
March 20, 2018: Nanoscale
Qiaoxian Huang, Shengke Li, Yuan-Fu Ding, Hang Yin, Lian-Hui Wang, Ruibing Wang
Due to its outstanding capability to facilitate DNA condensation, transportation and endosomal escape, polyethylenimine (PEI) has been frequently studied for gene delivery. However, its molecular weight (M.W.) dependent transfection efficiency and cytotoxicity has severely limited its clinical application. To resolve this dilemma, a supramolecular strategy was developed for the first time, in which PEI with large M.W. (branched, 25 kDa) that has a satisfactory transfection efficiency, yet high non-specific cytotoxicity for gene delivery was wrapped with macrocyclic cucurbit[7]uril (CB[7])...
March 20, 2018: Biomaterials Science
Maziar Derakhshandeh, Brandy K Pilapil, Ben Workman, Milana Trifkovic, Steven L Bryant
Emulsions are widely used in industrial applications, including in food sciences, cosmetics, and enhanced oil recovery. For these industries, an in depth understanding of the stability and rheological properties of emulsions under both static and dynamic conditions is vital to their successful application. Presented here is a thorough assessment of a model nanoparticle (NP) stabilized dodecane-in-water emulsion as a route to improved understanding of the relationship between NP properties, microstructure and droplet-droplet interactions on the stability and rheological properties of emulsions...
March 20, 2018: Soft Matter
Ying-Hua Zhao, Shi-Jian Zhang, Zi-Hui Yang, Xiao-Chang Liu, De-Lin Lei, Jing Li, Lei Wang
Distraction osteogenesis is an important technique for the treatment of maxillofacial abnormities and defects. However, distraction osteogenesis may cause the injury of the inferior alveolar nerve. The relationship between distraction rate and nerve degeneration-regeneration shift remains poorly understood. In this study, 24 rabbits were randomly divided into four groups. To establish the rabbit mandibular distraction osteogenesis model, the mandibles of rabbits in distraction osteogenesis groups were subjected to continuous osteogenesis distraction at a rate of 1...
February 2018: Neural Regeneration Research
Jing-Wen Zhang, Bo Pang, Qi Zhao, Yue Chang, Yi-Li Wang, Yi-Deng Jiang, Li Jing
Hyperhomocysteinemia has been shown to be associated with neurodegenerative diseases; however, lesions or histological changes and mechanisms underlying homocysteine-induced injury in olfactory bulb neurons remain unclear. In this study, hyperhomocysteinemia was induced in apolipoprotein E-deficient mice with 1.7% methionine. Pathological changes in the olfactory bulb were observed through hematoxylin-eosin and Pischingert staining. Cell apoptosis in the olfactory bulb was determined through terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining...
February 2018: Neural Regeneration Research
Martin Konečný, Miroslav Bartosik, Jindrich Mach, Vojtěch Švarc, David Nezval, Jakub Piastek, Pavel Procházka, Aleš Cahlík, Tomas Sikola
The article shows how the dynamic mapping of surface potential (SP) measured by Kelvin Probe Force Microscopy in combination with a calculation of diffusion-like equation and the theory based on the Brunauer-Emmett-Teller (BET) model of water condensation and electron hopping can provide the information concerning the resistivity of low conductive surfaces and their water coverage. This is enabled by a study of charge transport between isolated and grounded graphene sheets on a silicon dioxide surface at different relative humidity (RH) with regard to the use of graphene in ambient electronic circuits, and especially in sensors...
March 20, 2018: ACS Applied Materials & Interfaces
Dejian Zhou, Xing Zhu, Sanduo Zheng, Dan Tan, Meng-Qiu Dong, Keqiong Ye
Assembly of eukaryotic ribosome is a complicated and dynamic process that involves a series of intermediates. It is unknown how the highly intertwined structure of 60S large ribosomal subunits is established. Here, we report the structure of an early nucleolar pre-60S ribosome determined by cryo-electron microscopy at 3.7 Å resolution, revealing a half-assembled subunit. Domains I, II and VI of 25S/5.8S rRNA pack tightly into a native-like substructure, but domains III, IV and V are not assembled. The structure contains 12 assembly factors and 19 ribosomal proteins, many of which are required for early processing of large subunit rRNA...
March 19, 2018: Protein & Cell
Haoshi Gao, Yue Wei, Long Xi, Yuanyuan Sun, Tianhong Zhang
Bergenin (BN) is a Biopharmaceutics Classification System class IV (BCS IV) drug with poor hydrophilicity and lipophilicity and is potentially eliminated by the efflux function of P-glycoprotein (P-gp). These factors may explain its low oral bioavailability. In the present study, a BN-phospholipid complex solid dispersion (BNPC-SD) was prepared by solvent evaporation and characterized based on differential scanning calorimetry, powder X-ray diffraction, scanning electron microscopy, infrared diffraction, solubility, octanol-water partition coefficient, and in vitro dissolution...
March 19, 2018: AAPS PharmSciTech
Weiwei Zhao, Mingda Li, Cui-Zu Chang, Jue Jiang, Lijun Wu, Chaoxing Liu, Jagadeesh S Moodera, Yimei Zhu, Moses H W Chan
The exact mechanism responsible for the significant enhancement of the superconducting transition temperature ( T c ) of monolayer iron selenide (FeSe) films on SrTiO3 (STO) over that of bulk FeSe is an open issue. We present the results of a coordinated study of electrical transport, low temperature electron energy-loss spectroscopy (EELS), and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) measurements on FeSe/STO films of different thicknesses. HAADF-STEM imaging together with EELS mapping across the FeSe/STO interface shows direct evidence of electrons transferred from STO to the FeSe layer...
March 2018: Science Advances
Yuanyuan Zhao, Zhanyong Wang, Jing Zhang, Tingting Su
The production of Hasma generates plentiful non-edible by-products in China and Central Asia. As one of main by-products, the skin of Rana chensinensis is discarded as waste without utilization. In this work, R. chensinensis skin collagen (RCSC) hydrolysates were extracted using pepsin under acidic conditions. The yield of RCSC is 15.1% (w/w). Amino acid analysis revealed that RCSC contained glycine (204.5/1000 residues) and imino acids (182/1000 residues). RCSC exhibited high solubility in acidic pH (1-4) and low NaCl concentrations (< 2%, w/v)...
March 2018: 3 Biotech
Zahra Heidari, Ali Salehzadeh, Seyed Ataollah Sadat Shandiz, Sara Tajdoost
This study highlights the anti-oxidant and anti-cancer activities of bio-functionalized Thymus vulgaris silver nanoparticles (TVAgNPs) and bioactive compounds were compared using the human breast cancer T47D cell line. The aqueous ethanolic extract of T. vulgaris evaluated for chemical composition using the gas chromatography-mass spectrometer (GC-MS) analysis. The prepared TVAgNPs were determined by means of UV-Vis spectroscopy, FTIR spectroscopy, zeta potential, scanning electron microscopy, transmission electron microscopy, and energy-dispersed spectroscopy analysis...
March 2018: 3 Biotech
Bassem Khemakhem, Slim Smaoui, Hanen El Abed, Imen Fendri, Hajer Hammami, Mohamed Ali Ayadi
Three different concentrations of a purified maltogenic amylase (FSA) from fenugreek ( Trigonella foenum graecum ) seeds were incorporated into the cake formulation. The addition of FSA at 0.003, 0.005 and 0.01 U/g of cake increased the loaf volume, the number of holes (gas cells), and water absorption. Textural study revealed an improvement of the cake quality, resulting in the decrease of hardness and the increase of cohesion. Environmental scanning electron microscopy was performed on different cakes to evaluate the influence of amylase activity on microstructure...
March 2018: 3 Biotech
Yan Sun, Yong-Hao Huang, Feng-Ying Huang, Wen-Li Mei, Quan Liu, Cai-Chun Wang, Ying-Ying Lin, Canhua Huang, Yue-Nan Li, Hao-Fu Dai, Guang-Hong Tan
Rationale: Cardenolides have potential as anticancer drugs. 3'-epi-12β-hydroxyfroside (HyFS) is a new cardenolide structure isolated by our research group, but its molecular mechanisms remain poorly understood. This study investigates the relationship between its antitumor activities and autophagy in lung cancer cells. Methods: Cell growth and proliferation were detected by MTT, lactate dehydrogenase (LDH) release, 5-ethynyl-20-deoxyuridine (EDU) and colony formation assays. Cell apoptosis was detected by flow cytometry...
2018: Theranostics
Lizhou Lin, Yu Fan, Feng Gao, Lifang Jin, Dan Li, Wenjie Sun, Fan Li, Peng Qin, Qiusheng Shi, Xiangyang Shi, Lianfang Du
Conventional chemotherapy of pancreatic cancer (PaCa) suffers the problems of low drug permeability and inherent or acquired drug resistance. Development of new strategies for enhanced therapy still remains a great challenge. Herein, we report a new ultrasound-targeted microbubble destruction (UTMD)-promoted delivery system based on dendrimer-entrapped gold nanoparticles (Au DENPs) for co-delivery of gemcitabine (Gem) and miR-21 inhibitor (miR-21i). Methods: In this study, Gem-Au DENPs/miR-21i was designed and synthesized...
2018: Theranostics
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