Controllable adsorption of reduced graphene oxide onto self-assembled alkanethiol monolayers on gold electrodes: Tunable electrode dimension and potential electrochemical applications

This paper describes a facile and effective method to construct graphene nanosheet film (GNF) by controllable adsorption of reduced graphene oxide (rGO) onto the self-assembled monolayer (SAM) of n-octadecyl mercaptan (C(18)H(37)SH) at An electrodes. Nyquist plots show a gradual decrease of the charge transfer resistance (R(ct)) of the [Fe(CN)(6)](3-/4-) redox couple at the GNF/SAM electrode with prolonging the self-assembly time, Suggesting the controllable adsorption of rGO onto the SAM. Cyclic voltammetry (CV) studies reveal that the GNF/SAM electrodes have tunable dimensions ranging from a nanoelectrode ensemble to a conventional electrode, depending oil the self-assembly time of rGO. The excellent electrocatalytic activity of the GNF/SAM electrode toward ascorbic acid, dopamine, and uric acid further indicates that our approach is successful for the fabrication of stable GNF with excellent electrochemical properties, which is very attractive for electrochemical Studies and electroanalytical applications. At the same time, as a new kind of nanosheet film electrode, the GNF electrode Could be exploited in a new field for micro- and nanoelectrodes in electrochemical investigations and practical applications, e.g., electroanalysis in vivo and in vitro

Bitter melon (Momordica charantia) attenuates atherosclerosis in apo-E knock-out mice possibly through reducing triglyceride and anti-inflammation

Abstract Background Bitter melon (BM, Momordica charantia) has been accepted as an effective complementary treatment of metabolic disorders such as diabetes, hypertension, dyslipidemia and etc. However it is unclear whether BM can prevent the progression of atherosclerosis. To confirm the effects of BM on atherosclerosis and explore its underlying mechanisms, we design this study. Methods Twenty four male apolipoprotein E knock-out (ApoE-/-) mice aged 8 weeks were randomly divided into control group fed with high fat diet (HFD) only and BM group fed with HFD mixed with 1.2%w/w BM. After 16 weeks, body weight, food intake, blood glucose, serum lipids were measured and the atherosclerotic plaque area and its histological composition were analyzed. The expression of vascular cell adhesive molecules and inflammatory cytokines in the aortas were determined using quantitative polymerase chain reaction. Results Body weight gain and serum triglycerides (TG) significantly decreased in BM group. BM reduced not only the atherosclerotic plaque area and the contents of collagen fibers in atherosclerotic plaques but also the serum soluble vascular cell adhesion molecule (VCAM)-1 and P-selectin levels, as well as the expressions of monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-6 in aortas. Conclusion Our study indicates that dietary BM can attenuate the development of atherosclerosis in ApoeE-/- mice possibly through reducing triglyceride and anti-inflammation mechanism

Functional analysis of synthetic DELLA domain peptides and bioactive gibberellin assay using surface plasmon resonance technology

DELLA proteins and phytohormone gibberellin act together to control convergence point of plant development. A gibberellin-bound nuclear receptor that interacts with the N-terminal domain of DELLA proteins is required for gibberellin induced degradation of DELLA proteins. N-terminal DELLA domain includes two conserved motifs: DELLA and VHYNP. However, their respective functions remain unclear. Meanwhile, the identification and detection of several bioactive gibberellins from the more than 100 gibberellin metabolites are overwhelmingly difficult for their similar structures. Using in vitro biochemical approach, our work demonstrates for the first time that the synthetic GAI N-terminal DELLA domain peptides have similar bioactive function as the expressed protein to interact with AtGID1 a receptor. Furthermore, our results reveal that DELLA motif is vitally important region and DELLA segment is essentially required region to recognize AtGID1a receptor. Finally, based on bioactive GA-dependent of the interaction between AtGID1a and DELLA protein, we generated a new method that could identify and detect bioactive GAs accurately and rapidly with surface plasmon resonance assays. (C) 2015 Elsevier B.V. All rights reserved

Comprehensive understanding on the formation of highly ordered mesoporous tungsten oxides by X-ray diffraction and Raman spectroscopy

Highly ordered mesoporous tungsten oxides (WO3) have been synthesized via the hard templating method using mesoporous silica as a hard template and phosphotungstic acid as a precursor. The influences of the calcination temperature, the impregnation ratio of the precursor to the silica hard template and the hydrothermal treatment time of the silica template on the structure of products have been systematically investigated. Both X-ray diffraction and Raman spectroscopy were performed to study the crystalline phases of the resultant mesoporous WO3 as a function of the calcination temperature. The ideal calcination temperature for the synthesis of highly ordered mesoporous WO3 is found to be between 823 and 1073 K. Only a small fraction of crystalline WO3 can be detected in the composites when the calcination temperature is below 773 K. When the calcination temperature is increased from 773 to 1173 K, the monoclinic and triclinic phases of WO3 coexist in the products. Moreover, the ratio of the monoclinic to triclinic phase changes with the variation of the calcination temperature, and it reaches a maximum at about 923 K. Increasing the hydrothermal treatment time of the silica template KIT-6 to 5 days at 373 K favors the synthesis of highly ordered mesoporous WO3. When KIT-6 prepared without hydrothermal treatment is used as the hard template, a symmetry transformation from View the MathML source to I41/a can be observed. The present work provides a convenient and reproducible method for the synthesis of highly ordered mesoporous WO3 materials with crystalline walls, which may find potential applications in different areas

Functional analysis of synthetic DELLA domain peptides and bioactive gibberellin assay using surface plasmon resonance technology

DELLA proteins and phytohormone gibberellin act together to control convergence point of plant development. A gibberellin-bound nuclear receptor that interacts with the N-terminal domain of DELLA proteins is required for gibberellin induced degradation of DELLA proteins. N-terminal DELLA domain includes two conserved motifs: DELLA and VHYNP. However, their respective functions remain unclear. Meanwhile, the identification and detection of several bioactive gibberellins from the more than 100 gibberellin metabolites are overwhelmingly difficult for their similar structures. Using in vitro biochemical approach, our work demonstrates for the first time that the synthetic GAI N-terminal DELLA domain peptides have similar bioactive function as the expressed protein to interact with AtGID1 a receptor. Furthermore, our results reveal that DELLA motif is vitally important region and DELLA segment is essentially required region to recognize AtGID1a receptor. Finally, based on bioactive GA-dependent of the interaction between AtGID1a and DELLA protein, we generated a new method that could identify and detect bioactive GAs accurately and rapidly with surface plasmon resonance assays. (C) 2015 Elsevier B.V. All rights reserved

Synthesis, structural characterization, <i>in vitro</i> cytotoxicities, and BSA interaction of di-organotin(IV) complexes derived from salicylaldehyde nicotinoyl hydrazone

<p>Two organotin(IV) compounds were synthesized from salicylaldehyde nicotinoyl hydrazone and the corresponding dialkyltin(IV) precursor. Their structures were determined by IR, elemental analysis, NMR, and single crystal X-ray diffraction analysis. Compound <b>1</b> exhibits a distorted trigonal bipyramidal geometry around tin, which is coordinated to the Schiff-base ligand in an enolic tridentate fashion. For <b>2</b>, structural analysis reveals that it is a centro-symmetric trimer, in which the central Sn adopts a six-coordinate octahedral geometry and the other two Sn ions adopt five-coordinate trigonal bipyramidal geometry. <i>In vitro</i> cytotoxicities of the compounds against three human cisplatin-resistant tumor cell lines (A549, HeLa, and MCF-7) were assessed by MTT assay. Further, the interaction of <b>1</b> and <b>2</b> with bovine serum albumin (BSA) has been explored by the titration method with fluorescence quenching spectra and synchronous fluorescence spectra. Studies reveal that di-n-butyltin(IV) complex <b>1</b> with significant antiproliferative effects in the cells shows stronger BSA interaction.</p

GRSF1 antagonizes age-associated hypercoagulability via modulation of fibrinogen mRNA stability

Abstract Age-associated hypercoagulability is accompanied by the increase of plasma levels of some coagulation factors including fibrinogen which may contribute to the increased risk of cardiovascular, cerebrovascular, and thrombotic diseases in elderly people. However, the underlying mechanism of increased plasma fibrinogen concentration during aging is still elusive. GRSF1 belongs to the heterogeneous nuclear ribonucleoproteins F/H (hnRNP F/H) subfamily. Here, we report that GRSF1 attenuates hypercoagulability via negative modulation of fibrinogen expression. We demonstrated that GRSF1 negatively regulated fibrinogen expression at both mRNA and protein levels. GRSF1 directly interacted with the coding region (CDS) of FGA, FGB, and FGG mRNAs, and decreased their stability thus mitigating fibrinogen expression. We further identified that only a few G-tracts within the Fib C domain of FGA, FGB, and FGG CDS and the qRRM2 domain of GRSF1 were required for their interaction. Moreover, we confirmed hypercoagulability and the decrease of GRSF1 expression level during mice aging. Functionally, GRSF1 overexpression in old mice liver decreased fibrinogen plasma level, reduced hypercoagulability, and mitigated blood coagulation activity, whereas GRSF1 knockdown in young mice liver increased fibrinogen plasma level and promoted blood coagulation activity. Collectively, our findings unveil a novel posttranscriptional regulation of fibrinogen by GRSF1 and uncover a critical role of GRSF1 in regulating blood coagulation activity