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https://www.readbyqxmd.com/read/28532004/corrosion-and-surface-modification-on-biocompatible-metals-a-review
#1
REVIEW
R I M Asri, W S W Harun, M Samykano, N A C Lah, S A C Ghani, F Tarlochan, M R Raza
Corrosion prevention in biomaterials has become crucial particularly to overcome inflammation and allergic reactions caused by the biomaterials' implants towards the human body. When these metal implants contacted with fluidic environments such as bloodstream and tissue of the body, most of them became mutually highly antagonistic and subsequently promotes corrosion. Biocompatible implants are typically made up of metallic, ceramic, composite and polymers. The present paper specifically focuses on biocompatible metals which favorably used as implants such as 316L stainless steel, cobalt-chromium-molybdenum, pure titanium and titanium-based alloys...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531976/synthesis-of-in-situ-formable-hydrogels-with-collagen-and-hyaluronan-through-facile-michael-addition
#2
Riwang Li, Zhengwei Cai, Zhiwen Li, Qian Zhang, Shuyun Zhang, Li Deng, Lu Lu, Lihua Li, Changren Zhou
To mimic the natural extracellular matrix (ECM) and to facilitate tissue regeneration, in-situ formable collagen/hyaluronan composite hydrogels were prepared by a facile approach via Michael addition reaction, with maleilated collagen (Col-MA) and thiol derivatized hyaluronan (HA-SH). The hydrogels were denoted as CHG-1, CHG-2, CHG-3 and CHG-4 by vinyl/free thiol molar ratio (f) of 1:1, 1:2, 1:3 and 1:4, respectively. Results showed that with decrease of the f values, the gelation time decreased from 43s to 15s, Young's modulus increased from 1671...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531867/the-efficacy-of-steroids-for-postoperative-persistent-inflammatory-reaction-in-a-patient-with-barium-peritonitis-a-case-report
#3
Hirofumi Kojima, Shozo Hojo, Takahiro Manabe, Shiori Demura, Shinichi Sekine, Kazuto Shibuya, Isaya Hashimoto, Isaku Yoshioka, Tomoyuki Okumura, Takuya Nagata, Tsutomu Fujii
INTRODUCTION: Barium peritonitis is a serious and life-threatening disease requiring intensive care. Residual barium in the intraperitoneal cavity can cause persistent inflammation, postoperatively. PRESENTATION OF CASE: An 80-year-old woman was admitted to our hospital because of abdominal pain and vomiting after barium meal examination. Physical and radiographic examination showed sigmoid colon perforation. Barium sulfate extravasation was noted in the intraperitoneal cavity...
May 15, 2017: International Journal of Surgery Case Reports
https://www.readbyqxmd.com/read/28531339/limtox-a-web-tool-for-applied-text-mining-of-adverse-event-and-toxicity-associations-of-compounds-drugs-and-genes
#4
Andres Cañada, Salvador Capella-Gutierrez, Obdulia Rabal, Julen Oyarzabal, Alfonso Valencia, Martin Krallinger
A considerable effort has been devoted to retrieve systematically information for genes and proteins as well as relationships between them. Despite the importance of chemical compounds and drugs as a central bio-entity in pharmacological and biological research, only a limited number of freely available chemical text-mining/search engine technologies are currently accessible. Here we present LimTox (Literature Mining for Toxicology), a web-based online biomedical search tool with special focus on adverse hepatobiliary reactions...
May 22, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28531092/effective-silicon-nanowire-arrays-wo3-core-shell-photoelectrode-for-neutral-ph-water-splitting
#5
Zhen Chen, Ning Minghui, Ge Ma, Qingguo Meng, Yongguang Zhang, Jinwei Gao, Mingliang Jin, Zhihong Chen, Mingzhe Yuan, Xin Wang, Junming Liu, Guofu Zhou
We report the first demonstration of a high-efficiency photoelectrochemical (PEC) water splitting reaction using a novel Si NWs/WO3 core/shell photoanode prepared by a mild and inexpensive metal-catalyzed electroless etching (MCEE) process followed by dip-coating, airing and annealing methods. The dense and vertically aligned Si NWs/WO3 core/shell nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In comparison to planar n-Si, Si NWs and planar Si/WO3, the Si NWs/WO3 samples showed significantly enhanced photocurrent over the entire potential sweep range...
May 22, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28530808/%C3%AE-halo-amides-as-competent-latent-enolates-direct-cata-lytic-asymmetric-mannich-type-reaction
#6
Bo Sun, Pandur Venkatesan Balaji, Naoya Kumagai, Masakatsu Shibasaki
α-Halogenated carbonyl compounds are susceptible to dehalogenation and thus largely neglected as enolate precursors in catalytic enantioselective C-C bond forming reactions. By merging the increased stability of the α-C-halogen bond of amides and the direct enolization methodology of the designed amide, we explored a direct catalytic asymmetric Mannich-type reaction of α-halo 7-azaindoline amides with N-carbamoyl imines. All α-halo sub-stituents, α-F, -Cl, -Br, -I amides, were tolerated to provide the Mannich-adducts in a highly stereoselective manner without undesirable dehalogenation...
May 22, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28530798/heterogeneous-molecular-catalysis-of-electrochemical-reactions-volcano-plots-and-catalytic-tafel-plots
#7
Cyrille Costentin, Jean-Michel Savéant
We analyze here, in the framework of heterogeneous mo-lecular catalysis the reasons of occurrence or non-occurrence of volcanoes upon plotting the kinetics of the catalytic reaction versus the stabilization free energy of the primary intermediate of the catalytic process. As in the case of homogeneous molecular catalysis or catalysis by surface active metallic sites, a strong motivation of such studies relates to modern energy challenges, particularly those involving small molecules such as water, hydrogen, oxygen, proton and carbon dioxide...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28530740/extraction-behaviour-and-mechanism-of-pt-iv-and-pd-ii-by-liquid-liquid-extraction-with-an-ionic-liquid-hbbim-br
#8
Wenhui Liu, Qi Wang, Yan Zheng, Shubin Wang, Yan Yan, Yanzhao Yang
In this study, a method of one-step separation and recycling of high purity Pd(ii) and Pt(iv) using an ionic liquid, 1-butyl-3-benzimidazolium bromate ([HBBIm]Br), was investigated. The effects of [HBBIm]Br concentration, initial metal concentration, and loading capacity of [HBBIm]Br were examined in detail. It was observed that [HBBIm]Br was a very effective extractant for selectively extracting Pd(ii) and precipitating Pt(iv). Through selectively extracting Pd(ii) and precipitating Pt(iv), each metal with high purity was separately obtained from mixed Pd(ii) and Pt(iv) multi-metal solution...
May 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28530560/lactulose-production-from-efficient-isomerization-of-lactose-catalyzed-by-recyclable-sodium-aluminate
#9
Mingming Wang, Mohammed A A Gasmalla, Habtamu Admassu Tessema, Xiao Hua, Ruijin Yang
An efficient strategy for the synthesis of high-purity lactulose through chemical isomerization of lactose was developed using recyclable catalyst sodium aluminate. Maximum yield of 85.45±1.79% was obtained from 35% (w/v) of lactose using a 1:1M ratio of NaAlO2-lactose after reaction at 60°C and pH 12 for 50min, with a purity ratio (Pu) of approximately 95%. Al(OH)3 precipitation from lactulose syrup through pH adjustment showing a superior decolorizing efficiency was implemented, which simplified the removal of catalyst and provided a convenient approach to achieve catalyst recovery...
October 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28530554/simultaneous-determination-of-fumonisins-b1-and-b2-in-different-types-of-maize-by-matrix-solid-phase-dispersion-and-hplc-ms-ms
#10
Gabriel Barros de Oliveira, Carolyne Menezes de Castro Gomes Vieira, Ricardo Mathias Orlando, Adriana Ferreira Faria
This work involved the optimization and validation of a method, according to Directive 2002/657/EC and the Analytical Quality Assurance Manual of Ministério da Agricultura, Pecuária e Abastecimento, Brazil, for simultaneous extraction and determination of fumonisins B1 and B2 in maize. The extraction procedure was based on a matrix solid phase dispersion approach, the optimization of which employed a sequence of different factorial designs. A liquid chromatography-tandem mass spectrometry method was developed for determining these analytes using the selected reaction monitoring mode...
October 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28530294/electrochemical-nanoimprint-lithography-when-nanoimprint-lithography-meets-metal-assisted-chemical-etching
#11
Jie Zhang, Lin Zhang, Lianhuan Han, Zhao-Wu Tian, Zhong-Qun Tian, Dongping Zhan
The functional three dimensional micro-nanostructures (3D-MNS) play crucial roles in integrated and miniaturized systems because of the excellent physical, mechanical, electric and optical properties. Nanoimprint lithography (NIL) has been versatile in the fabrication of 3D-MNS by pressing thermoplastic and photocuring resists into the imprint mold. However, direct nanoimprint on the semiconductor wafer still remains a great challenge. On the other hand, considered as a competitive fabrication method for erect high-aspect 3D-MNS, metal assisted chemical etching (MacEtch) can remove the semiconductor by spontaneous corrosion reaction at the metal/semiconductor/electrolyte 3-phase interface...
May 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/28530248/single-molecule-detection-of-dihydroazulene-photo-thermal-reaction-using-break-junction-technique
#12
Cancan Huang, Martyn Jevric, Anders Borges, Stine T Olsen, Joseph M Hamill, Jue-Ting Zheng, Yang Yang, Alexander Rudnev, Masoud Baghernejad, Peter Broekmann, Anne Ugleholdt Petersen, Thomas Wandlowski, Kurt V Mikkelsen, Gemma C Solomon, Mogens Brøndsted Nielsen, Wenjing Hong
Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system...
May 22, 2017: Nature Communications
https://www.readbyqxmd.com/read/28529842/an-environmental-transfer-hub-for-multimodal-atom-probe-tomography
#13
Daniel E Perea, Stephan S A Gerstl, Jackson Chin, Blake Hirschi, James E Evans
Environmental control during transfer between instruments is required for samples sensitive to air or thermal exposure to prevent morphological or chemical changes prior to analysis. Atom probe tomography is a rapidly expanding technique for three-dimensional structural and chemical analysis, but commercial instruments remain limited to loading specimens under ambient conditions. In this study, we describe a multifunctional environmental transfer hub allowing controlled cryogenic or room-temperature transfer of specimens under atmospheric or vacuum pressure conditions between an atom probe and other instruments or reaction chambers...
2017: Advanced Structural and Chemical Imaging
https://www.readbyqxmd.com/read/28529817/coordinated-and-iterative-enzyme-catalysis-in-fungal-polyketide-biosynthesis
#14
Leibniz Hang, Nicholas Liu, Yi Tang
Fungal polyketides are natural products with great chemical diversity that exhibit a wide range of biological activity. This chemical diversity stems from specialized enzymes encoded in the biosynthetic gene cluster responsible for the natural product biosynthesis. Fungal polyketide synthases (PKS) are the megasynthases that produce the carbon scaffolds for the molecules. Subsequent downstream tailoring enzymes such as oxygenases will then further modify the organic framework. In fungi, many of these enzymes have been found to work iteratively-catalyzing multiple reactions on different sites of the substrate...
September 2, 2016: ACS Catalysis
https://www.readbyqxmd.com/read/28529769/une-surstructure-de-%C3%AE-ge-type-diamant-induite-par-un-dopage-d-anti-moine
#15
Adrian Gómez Herrero, Lamia Hammoudi, Mohammed Kars, Thierry Roisnel, L Carlos Otero-Diáz
Single crystals of anti-mony-doped germanium, Ge1-x Sb x+0.01 (x ≃ 0.0625), were grown by chemical transport reaction. The alloy crystallizes as a superstructure of diamond-type α-Ge. All atoms in the asymmetric unit lie on special positions and are characterized by strong covalent bonds. The anti-mony atoms substitute for one germanium atom at full occupancy at Wyckoff position 4a (site symmetry -43m), and are also at an adjacent tetra-hedral inter-stitial site with partially occupation (16%) at position 4c (or 4d) (site symmetry -43m)...
May 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28529675/role-of-dissociatively-adsorbed-water-on-the-formation-of-shallow-trapped-electrons-in-tio2-photocatalysts
#16
Anton Litke, Emiel J M Hensen, Jan P Hofmann
The mismatch between short lifetimes of free charge carriers and slow kinetics of surface redox reactions substantially limits the efficiency of most photocatalytic systems. Hence, the knowledge of trapping and recombination of photogenerated electrons and holes at different time scales is key for a rational optimization of photocatalytic materials. In this study, we used subsecond time-resolved diffuse-reflectance FTIR spectroscopy to investigate how energy and intensity of the incident irradiation affect the dynamics of photogenerated charge carriers in TiO2 P25 photocatalysts subjected to different pretreatments and how shallow trapped electrons (STE) are formed under these conditions...
May 11, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/28528876/modeling-covalent-modifier-drugs
#17
REVIEW
Ernest Awoonor-Williams, Andrew G Walsh, Christopher N Rowley
In this review, we present a summary of how computer modeling has been used in the development of covalent modifier drugs. Covalent modifier drugs bind by forming a chemical bond with their target. This covalent binding can improve the selectivity of the drug for a target with complementary reactivity and result in increased binding affinities due to the strength of the covalent bond formed. In some cases, this results in irreversible inhibition of the target, but some targeted covalent inhibitor (TCI) drugs bind covalently but reversibly...
May 18, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28528861/mechanism-of-melatonin-protection-against-copper-ascorbate-induced-oxidative-damage-in-vitro-through-isothermal-titration-calorimetry
#18
Arnab K Ghosh, Shamreen Naaz, Bharati Bhattacharjee, Nirajan Ghosal, Aindrila Chattopadhyay, Souvik Roy, Russel J Reiter, Debasish Bandyopadhyay
AIMS: Involvement of oxidative stress in cardiovascular diseases is well established. Melatonin's role as an antioxidant and free radical scavenger via its receptor dependent and receptor independent pathways is well known. The aim of this study is to identify and elaborate upon a third mechanism by which melatonin is able to abrogate oxidative stress. MAIN METHODS: Oxidative stress was induced in vitro, by copper (0.2mM)-ascorbate (1mM) in isolated goat heart mitochondria, cytosol and peroxisomes and they were co-incubated with graded doses of melatonin...
May 18, 2017: Life Sciences
https://www.readbyqxmd.com/read/28528682/chemical-fixation-to-arrest-phospholipid-signaling-for-chemical-cytometry
#19
Angela Proctor, Christopher E Sims, Nancy L Allbritton
Chemical cytometry is a powerful tool for measuring biological processes such as enzymatic signaling at the single cell level. Among these technologies, single-cell capillary zone electrophoresis (CZE) has emerged as a powerful tool to assay a wide range of cellular metabolites. However, analysis of dynamic processes within cells remains challenging as signaling pathways are rapidly altered in response to changes in the cellular environment, including cell manipulation and storage. To address these limitations, we describe a method for chemical fixation of cells to stop the cellular reactions to preserve the integrity of key signaling molecules or reporters within the cell and to enable the cell to act as a storage reservoir for the reporter and its metabolites prior to assay by single-cell CZE...
May 10, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28528133/chemical-synthesis-of-flower-like-hybrid-cu-oh-2-cuo-electrode-application-of-polyvinyl-alcohol-and-triton-x-100-to-enhance-supercapacitor-performance
#20
S K Shinde, V J Fulari, D-Y Kim, N C Maile, R R Koli, H D Dhaygude, G S Ghodake
In this research article, we report hybrid nanomaterials of copper hydroxide/copper oxide (Cu(OH)2/CuO). A thin films were prepared by using a facile and cost-effective successive ionic layer adsorption and reaction (SILAR) method. As-synthesized and hybrid Cu(OH)2/CuO with two different surfactants polyvinyl alcohol (PVA) and triton-X 100 (TRX-100) was prepared having distinct morphological, structural, and supercapacitor properties. The surface of the thin film samples were examined by scanning electron microscopy (SEM)...
May 9, 2017: Colloids and Surfaces. B, Biointerfaces
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