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Sait Bozkurt, Berna Tosun, Betül Sen, Süleyman Akocak, Aysun Savk, Mehmet Faruk Ebeoğlugil, Fatih Sen
Addressed herein, we report the synthesis and characterization of a tert-nonyl mercaptan (TNM) functionalized reduced graphene oxide (rGO) supported palladium (Pd) nanoparticles (NPs) (Pd/TNM@rGO) as electrochemical sensor. The highly monodisperse Pd/TNM@rGO nanocomposite was applied for electrochemical determination of hydrogen peroxide (H2O2) at a potential range of -0.6 to +0.8 V. The Pd/TNM@rGO sensor demonstrated very high activity, sensitivity, reusability and durability toward H2O2 sensing. The well dispersed Pd/TNM@rGO nanocomposite has been characterized by using several analytical techniques such as, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) and electrochemical impedance spectroscopy (EIS)...
October 9, 2017: Analytica Chimica Acta
Qisheng Tang, Yuxi Lian, Jinhua Yu, Yuanyuan Wang, Zhifeng Shi, Liang Chen
BACKGROUND: Tumor location served as an important prognostic factor in glioma patients was considered to postulate molecular features according to cell origin theory. However, anatomic distribution of unique molecular subtypes was not widely investigated. The relationship between molecular phenotype and histological subgroup were also vague based on tumor location. Our group focuses on the study of glioma anatomic location of distinctive molecular subgroups and histology subtypes, and explores the possibility of their consistency based on clinical background...
September 15, 2017: BMC Neurology
Chiara Pesenti, Leda Paganini, Laura Fontana, Emanuela Veniani, Letterio Runza, Stefano Ferrero, Silvano Bosari, Maura Menghi, Giovanni Marfia, Manuela Caroli, Rosamaria Silipigni, Silvana Guerneri, Silvia Tabano, Monica Miozzo
The World Health Organization recently revised the diagnosis of glioma, to integrate molecular parameters, including IDH mutations and codeletion (loss of heterozygosity; LOH) of chromosome arms 1p/19q, into the definitions of adult glioma histological subtypes. Mutations in the TERT promoter may also be useful for glioma diagnosis and prognosis. The integration of molecular markers into routine diagnosis requires their rapid and reliable assessment. We propose a MassARRAY (MS)-based test that can identify 1p/19q codeletion using quantitative SNP genotyping and, simultaneously, characterize hotspot mutations in the IDH1, IDH2, and TERT genes in tumor DNA...
August 22, 2017: Oncotarget
Chuang Li, Zixuan Zhao, Jun Zhou, Ying Liu, Hao Wang, Xinhan Zhao
Colorectal cancer (CRC) is one of the most common diseases worldwide, and telomere length has been reported correlate with CRC. This study aimed to investigate whether polymorphisms of telomere length related genes are associated with susceptibility to CRC in Chinese Han population. 11 SNPs from TERT, TNIP1 and OBFC1 genes were selected and genotyped, in addition odds ratio (OR) and 95% confidence intervals (CI) were used to evaluate association between the SNPs and CRC risk in 247 patients clinically and 300 controls in a Chinese Han population...
August 22, 2017: Oncotarget
Zi-Yi Chen, Dennis Y S Tam, Leon Li-Min Zhang, Thomas Chung Wai Mak
A series of seven new complexes including silver-thiolate molecular clusters and their covalent supramolecular frameworks have been assembled from the silver carbide precursor Ag2C2 using a C22- pre-templated approach. Herein, two prototype clusters Ag14(SR)6 and CO3@Agm(SR)10 (R = isopropyl, cyclohexyl or tert-butyl; m = 18 or 20) are employed to construct cluster-based metal-organic frameworks of different dimensions. In particular, both new ellipsoidal tetradecanuclear molecular cluster compounds, namely Ag14(S-iPr)6(CF3CO2)8·DMSO6 (two polymorphic forms 1, 2) and [Ag14(S-Cy)6(CO2CF3)8(DMSO)4] · DMSO3 (3), and a cluster-based metal-organic framework {Ag3[Ag14(S-iPr)6(CF3CO2)11(H2O)3CH3OH] · (H2O)2...
September 15, 2017: Chemistry, An Asian Journal
Yu-Ling Wu, Jui-Chih Chang, Wei-Yong Lin, Chien-Chun Li, Mingli Hsieh, Haw-Wen Chen, Tsu-Shing Wang, Chin-San Liu, Kai-Li Liu
Spinocerebellar ataxia type 3 (SCA3) is caused by the expansion of a polyglutamine (polyQ) repeat in the protein ataxin-3 which is involved in susceptibility to mild oxidative stress induced neuronal death. Here we show that caffeic acid (CA) and resveratrol (Res) decreased reactive oxygen species (ROS), mutant ataxin-3 and apoptosis and increased autophagy in the pro-oxidant tert-butyl hydroperoxide (tBH)-treated SK-N-SH-MJD78 cells containing mutant ataxin-3. Furthermore, CA and Res improved survival and locomotor activity and decreased mutant ataxin-3 and ROS levels in tBH-treated SCA3 Drosophila...
September 14, 2017: Scientific Reports
Sameh R Hussein, Mona M Marzouk, Maha M Soltan, Emad K Ahmed, Mahmoud M Said, Ahmed R Hamed
One new naturally isoflavone compound, 5,7,2',3',4' penta hydroxyl isoflavone-4'-O-β-glucopyranoside (1) was isolated from the aqueous methanol extract (AME) of Pulicaria undulata subsp. undulata, together with seven known compounds: kaempferol (2), kaempferol 3-O-β-glucoside (3), quercetin (4), quercetin 3-O-β-glucoside (5), quercetin 3-O-β-galactoside (6), quercetin 3,7-di OCH3 (7), and caffeic acid (8). Their structures were established through chemical (acid hydrolysis) and spectral analysis (UV, NMR, and ESIM)...
April 2017: Journal of Food and Drug Analysis
Wei Huang, Hui Liu, Yan-Jun Xu, Chong-Dao Lu
A single-flask reaction of silyllithium, α-keto N-tert-butanesulfinyl imidates and aldehydes has been developed for diastereoselective synthesis of α,β-dihydroxy acid derivatives. In this reaction, nucleophilic addition of silyllithium to chiral α-keto imidates followed by silyl migration forms chiral aza-enolates, which react diastereoselectively with aldehydes. Subsequent [1,4]-O to O silyl migration affords α-substituted β-(silyoxy)-α-hydroxy imidates.
September 14, 2017: Journal of Organic Chemistry
Sara Meninno, Angelo Roselli, Amedeo Capobianco, Jacob Overgaard, Alessandra Lattanzi
Readily available chiral amine-thioureas are effective catalysts for the first diastereo- and enantioselective epoxidation of unsaturated pyrazolones. The trans- or cis-spiroepoxides are preferentially obtained in good yield and high to excellent enantioselectivity using an appropriate organocatalyst and tert-butyl hydroperoxide as the oxidant. The epoxidation appears applicable to highly challenging β,β'-substituted unsaturated pyrazolones, giving access to spiroepoxides bearing two vicinal quaternary stereocenters...
September 14, 2017: Organic Letters
Mihail Kazak, Martins Priede, Kirill Shubin, Hannah E Bartrum, Jean-François Poisson, Edgars Suna
An eight-step stereodivergent synthesis of enantiomerically pure (-)-14-epi-pseudotabersonine and (+)-pseudotabersonine has been developed from a common N-tert-butanesulfinyl ketimine key intermediate.
September 13, 2017: Organic Letters
Luis D Rosales-Vázquez, Víctor Sánchez-Mendieta, Alejandro Dorazco-González, Diego Martínez-Otero, Iván García-Orozco, Raúl A Morales-Luckie, Jonathan Jaramillo-Garcia, Antonio Téllez-López
Four coordination polymers have been synthesized using self-assembly solution reactions under ambient conditions, reacting Cd(ii) ions with 1,4-cyclohexanedicarboxylic acid in the presence of different 2,2'-bipyridine co-ligands: {[Cd(H2O)(e,a-cis-1,4-chdc)(2,2'-bpy)]·H2O}n (1); [Cd2(H2O)2(e,a-cis-1,4-chdc)2(4,4'-dmb)2]n (2); {[Cd(e,a-cis-1,4-chdc)(5,5'-dmb)]·H2O·CH3OH}n (3) and {[Cd(e,e-trans-1,4-chdc)(4,4'-dtbb)]·CH3OH}n (4), where 1,4-chdc = 1,4-cyclohexanedicarboxylato, 2,2'-bpy = 2,2'-bipyridine, 4,4'-dmb = 4,4'-dimethyl-2,2'-bipyridine, 5,5'-dmb = 5,5'-dimethyl-2,2'-bipyridine and 4,4'-dtbb = 4,4'-di-tert-butyl-2,2'-bipyridine...
September 13, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Maki Takeda, Keisuke Oyama, Norio Kamemura, Kaori Kanemaru, Keizo Yuasa, Kumio Yokoigawa, Yasuo Oyama
Tertiary butylhydroquinone (TBHQ) is a food additive and has various beneficial actions under in vitro and in vivo experimental conditions. Therefore, it is necessary to collect additional data on the toxicity of TBHQ in order to avoid adverse effects during clinical applications. Changes in plasma membrane potential are associated with changes in physiological functions even in non-excitable cells such as lymphocytes. Thus, compounds that affect membrane potential may modify some lymphocytic functions. The effect of TBHQ on plasma membrane potential was examined in rat thymocytes using flow cytometric techniques...
September 9, 2017: Food and Chemical Toxicology
Iga Nehring, Agnieszka Grajewska, Lucyna Falkowska, Marta Staniszewska, Iwona Pawliczka, Dominika Saniewska
The placenta is an intermediary organ between the female and the developing foetus. Some chemical substances, including the most harmful ones, exhibit the ability to accumulate in or penetrate through the placenta. The aim of the study was to determine the role of the placenta of the Baltic grey seal (Halichoerus grypus grypus) in the transfer of endocrine disrupting compounds (EDCs) - (bisphenol A, 4-tert- octylphenol, 4- nonylphenol), as well as total and organic mercury. 30 placentas were collected from grey seals pupping under human care at the Hel Marine Station in the years 2007-2016...
September 8, 2017: Environmental Pollution
Bas de Bruin, Christophe Rebreyend, Yann Gloaguen, Martin Lutz, Jarl Ivar van der Vlugt, Inke Siewert, Sven Schneider
One-electron oxidation of the rhodium(I) azido complex [Rh(N3)(PNP)] (5), bearing the neutral PNP ligand 2,6-bis(di-tert-butylphosphinomethyl)pyridine leads to instantaneous and selective formation of the mononuclear rhodium(I) dinitrogen complex [Rh(N2)(PNP)]+ (9+). Interestingly, complex 5 also acts as a catalyst for electrochemical N3- oxidation in the presence of excess azide at a substantially lower potential (Ep ~ -0.23 V vs. Fc+/0) than direct oxidation at Pt-electrodes (Ep ~ +0.19 V vs. Fc+/0). Cyclic voltammetry in the presence of an excess of N(nBu)4N3 reveals that electro-catalytic N3-oxidation occurs at roughly the same potential as the first oxidation wave of 5...
September 12, 2017: Chemistry: a European Journal
Zsolt Benedek, Balazs Orban, Tibor Szilvasi
We examine by the means of computational chemistry the ability of two phosphasilenes to transfer the phosphinidene moiety to four double bonded organic functional groups (>C=C<, -N=N-, >C=O, and >C=S) in the presence of different bulky ligands. We show that large bulky groups in the reactants can sterically prohibit the otherwise favored association of reactants and phosphasilenes and instead a new phosphinidene transfer reaction can occur. We find that the transfer reaction mechanism is generally present independent from the functional group and by introducing large enough trimethylsilyl or tert-butyl-dimethylsilyl ligands it can be used to transfer phosphinidene to organic functional groups such as thioformaldehydes or diazenes, respectively...
September 12, 2017: Chemistry: a European Journal
Tunc F Ersoy, Vera C Keil, Dariusch R Hadizadeh, Gerrit H Gielen, Rolf Fimmers, Andreas Waha, Barbara Heidenreich, Rajiv Kumar, Hans H Schild, Matthias Simon
PURPOSE: Magnetic resonance (MR) imaging biomarkers can assist in the non-invasive assessment of the genetic status in glioblastomas (GBMs). Telomerase reverse transcriptase (TERT) promoter mutations are associated with a negative prognosis. This study was performed to identify MR imaging biomarkers to forecast the TERT mutation status. METHODS: Pre-operative MRIs of 64/67 genetically confirmed primary GBM patients (51/67 TERT-mutated with rs2853669 polymorphism) were analyzed according to Visually AcceSAble Rembrandt Images (VASARI) ( https://wiki...
September 11, 2017: Neuroradiology
John Murphy, Andrew Smith, Allan Young, Simon Rohrbach, Erin O'Connor, Mark Allison, Hong-Shuang Wang, Darren Poole, Tell Tuttle
Recent studies by Stoltz, Grubbs et al. have shown that triethylsilane and potassium tert-butoxide react to form a highly attractive and versatile system that shows (reversible) silylation of arenes and heteroarenes as well as reductive cleavage of C-O bonds in aryl ethers and C-S bonds in aryl thioethers. Their extensive mechanistic studies indicate a complex network of reactions with a number of possible intermediates and mechanisms, but their reactions likely feature silyl radicals undergoing addition reactions and SH2 reactions...
September 11, 2017: Angewandte Chemie
Rita Issa, Michael Boeving, Michael Kinter, Timothy M Griffin
Mechanosensitve pathways in chondrocytes are essential for maintaining articular cartilage homeostasis. Traumatic loading increases cartilage oxidation and causes cell death and osteoarthritis. However, sub-lethal doses of the pro-oxidant molecule tert-Butyl hydroperoxide (tBHP) protects against loading-induced chondrocyte death. We hypothesized that compressive cyclic loading at moderate strains (<20%) causes sub-lethal cartilage oxidation that induces an adaptive increase in the endogenous antioxidant defense network...
September 11, 2017: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
Chengjiang Zhang, Xialin Luo, Tianfu Wei, Yufei Hu, Gongke Li, Zhuomin Zhang
A new dynamic covalent polymer (DCP) gel was well designed and constructed based on imine chemistry. Polycondensation of 4,4'-biphenyldicarboxaldehyde and 1,3,5-benzenetricarbohydrazide via Schiff-base reaction resulted in an acylhydrazone bond gel (AB-gel) DCP. AB-gel DCP had three-dimensional network of interconnected nanoparticles with hierarchically porous structure. AB-gel DCP was successfully fabricated as a monolithic column by an in-situ chemical bonding method for online enrichment and separation purpose with excellent permeability...
September 4, 2017: Journal of Chromatography. A
Virginia Rubio, Ana Isabel García-Pérez, Angel Herráez, M Cristina Tejedor, José C Diez
Esculetin is a polyphenolic compound with cytoprotective properties. We previously demonstrated the induction of apoptosis by esculetin in NB4 human leukemia cells, as a model, by a mechanism not well understood. To analyse the antioxidant activity of esculetin on apoptosis, we have studied the influence of co-treatments of esculetin at a concentration of 100μM with exogenous ROS donors, namely tert-butyl-hydroperoxide and hydrogen peroxide, on NB4 cells. Esculetin (100μM) exerts a protective effect on cell viability and death necrosis or late apoptosis caused by the oxidant t-BHP whereas it potentiates decrease of cell viability and cell death caused by H2O2...
September 7, 2017: Experimental and Toxicologic Pathology: Official Journal of the Gesellschaft Für Toxikologische Pathologie
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