Bovine serum albumin-sugar conjugates through the maillard reaction: effects on interfacial behavior and emulsifying ability

Bovine serum albumin (BSA) was employed as a model protein emulsifier to conjugate with aldohexose (D-glucose (Glc) or D-allose (All)) and sugar fatty acid ester (6-O-octanoyl-D-glucose (GlcC8)) through the Maillard reaction. It was found during the reaction that rate of decrease of free amino groups in BSA was almost the same for the BSA-sugar mixtures whereas browning and protein aggregation developed in the following order: Glc < All < GlcC8. It was thought that the rate of degradation of the Amadori compound could have been influenced by the OH-group stereochemistry at the C3 position of aldohexose, while denaturation of BSA by GlcC8 enhanced the browning and protein aggregation. To understand the emulsifying ability of the BSA-sugar conjugates, hexadecane-water interfacial tension and the oil droplet size of emulsions prepared by homogenizing hexadecane and aqueous solution of the conjugates were examined. BSA-GlcC8 showed greater improvement in interfacial and emulsifying activity than did BSA-Glc and -All. However, no improvement in emulsion stability was observed for any of the BSA-sugar conjugates, suggesting the weakness of the film formed at the oil droplet interface.     

Structural motif of phosphate-binding site common to various protein superfamilies: all-against-all structural comparison of proteinmononucleotide complexes

In order to search for a common structural motif in the phosphate-bindingsites of protein–mononucleotide complexes, we investigatedthe structural variety of phosphate-binding schemes by an all-against-allcomparison of 491 binding sites found in the Protein Data Bank.We found four frequently occurring structural motifs composedof protein atoms interacting with phosphate groups, each ofwhich appears in different protein superfamilies with differentfolds. The most frequently occurring motif, which we call thestructural P-loop, is shared by 13 superfamilies and is characterizedby a four-residue fragment, GXXX, interacting with a phosphategroup through the backbone atoms. Various sequence motifs, includingWalker's A motif or the P-loop, turn out to be a structuralP-loop found in a few specific superfamilies. The other threemotifs are found in pairs of superfamilies: protein kinase andglutathione synthetase ATPase domain like, actin-like ATPasedomain and nucleotidyltransferase, and FMN-linked oxidoreductaseand PRTase.     

Effect of Polymer Dispersant Structure on Electrosteric Interaction and Dense Alumina Suspension Behavior

The present paper reports on research on the effect of molecular structure of polymer dispersants on the relationship between the electrosteric interaction of dispersants on solid surfaces and the viscosity of suspensions. Ammonium polyacrylate with different hydrophilic to hydrophobic ratios ( m:n ) was prepared and added to dense Al₂O₃ suspensions (40 vol%). The steric interactions and adsorbed structures of dispersants on Al₂O₃ powders were examined under an atomic force microscope (AFM). An optimum hydrophilic to hydrophobic group ratio, which was obtained from the maximum repulsive force and the minimum viscosity of suspension, was determined at m :n = 3:7. The changing mechanism of the adsorbed structure and the steric interaction of dispersants and the suspension viscosity by the hydrophilic to hydrophobic molecular ratio were discussed by comparing the experimental force curve and DLVO theory.     

Superhydrophobic/superhydrophilic micropatterning on a carbon nanotube film using a laser plasma-type hyperthermal atom beam facility

Superhydrophobic/superhydrophilic micropatterning on a carbon nanotube (CNT) film has been achieved using a laser plasma-type hyperthermal atom beam facility, which produces a small amount of damage and generates a highly anisotropic beam. Fluorination and oxidation on CNT films by exposure to fluorine-atom and oxygen-atom beams caused superhydrophobic and superhydrophilic surfaces, respectively, while maintaining the as-grown fibrous forms of the CNT films. Micropatterned oxidation on CNT films without using photoresists created superhydrophilic microdots and microchannels.     

Identification of Tumor Suppressive Genes Regulated by miR-31-5p and miR-31-3p in Head and Neck Squamous Cell Carcinoma

We identified the microRNA (miRNA) expression signature of head and neck squamous cell carcinoma (HNSCC) tissues by RNA sequencing, in which 168 miRNAs were significantly upregulated, including both strands of the miR-31 duplex (miR-31-5p and miR-31-3p). The aims of this study were to identify networks of tumor suppressor genes regulated by miR-31-5p and miR-31-3p in HNSCC cells. Our functional assays showed that inhibition of miR-31-5p and miR-31-3p attenuated cancer cell malignant phenotypes (cell proliferation, migration, and invasion), suggesting that they had oncogenic potential in HNSCC cells. Our in silico analysis revealed 146 genes regulated by miR-31 in HNSCC cells. Among these targets, the low expression of seven genes (miR-31-5p targets: CACNB2 and IL34; miR-31-3p targets: CGNL1, CNTN3, GAS7, HOPX, and PBX1) was closely associated with poor prognosis in HNSCC. According to multivariate Cox regression analyses, the expression levels of five of those genes (CACNB2: p = 0.0189; IL34: p = 0.0425; CGNL1: p = 0.0014; CNTN3: p = 0.0304; and GAS7: p = 0.0412) were independent prognostic factors in patients with HNSCC. Our miRNA signature and miRNA-based approach will provide new insights into the molecular pathogenesis of HNSCC.     

Alloying effects on the hydride formation of Zr(Mn1−xCox)2

To study the alloying effects on ZrMn₂-H system, thermodynamic properties of Zr(Mn_1−xCo_x)₂ hydride were measured by volumetric method. ZrMn₂ gave a single plateau region in the pressure-composition isotherm. On the other hand, double plateaus were clearly observed in Zr(Mn_0.7Co_0.3)₂ and Zr(Mn_0.6Co_0.4)₂-H systems. The appearance of the double plateau characteristics would be explained in view of the hydrogen binding in the tetrahedral occupation sites in Zr(Mn_1−xCo_x)₂. Since the hydrogen binding in the tetrahedral 2ZrMnCo site would be less stable than that in the 2Zr2Mn site, the equilibrium pressure increases with increasing cobalt content. The appearance of the first plateau was ascribed the increase in the bonding of Mn-H in 2Zr2Mn site adjoining the 2ZrMnCo site.     

Preparation of Pt-loaded TiO2 nanofibers by electrospinning and their application for WGS reactions

Preparation of Pt-loaded TiO₂ nanofibers and their catalytic performance for water gas shift (WGS) reactions have been explained in this work. The Pt-loaded TiO₂ nanofibers were obtained by electrospinning poly-ethylene oxide (PEO) aqueous solutions containing Ti(OH)_n slurry and Pt nanoparticles at room temperature, followed by calcination at 773 K for 4 h. The calcined nanofibers were rougher than the nanofibers of PEO/Ti(OH)_n/Pt due to the PEO degradation and oxidation of Ti(OH)_n to TiO₂. Diameters of the Pt-loaded TiO₂ nanofibers ranged between 200 and 900 nm. Catalytic activity of the Pt-loaded TiO₂ nanofibers for water gas shift (WGS) reactions was evaluated and it was observed that their activity was 5–7 times higher than that of a bulk catalyst. Such improvement is attributed to the larger surface area of the nanofiber catalyst compared to that of the bulk catalyst. To the best of our knowledge, this is the first demonstration of a synthesis of Pt-loaded TiO₂ nanofibers from a Ti(OH)_n nanoparticle slurry using electrospinning and its application to WGS reactions.     

Electrochemical oxidation of carbon black in concentrated phosphoric acid at 135°C

The electrochemical oxidation of a high surface area carbon black (1000 m²/g) was investigated in 96% H₃PO₄ at 135°C. The total anodic current, the amount of CO₂ evolved and the oxygen content of the carbon were all measured as a function of time and potential. Two anodic processes occurred: the formation of a surface oxide and the evolution of CO₂. Both decreased with time but at different rates so that CO₂ evolution eventually became the major reaction. Various mechanisms to define the corrosion processes are discussed.     

氦对Fe-Cr-Ni合金和Fe-Cr-Mn合金辐照损伤的影响

利用超高压电镜与高能离子加速器连接装置 ,研究了氦 (He)对Fe Cr Ni和Fe Cr Mn两类奥氏体型合金辐照损伤行为的影响。观察了辐照过程中二次点缺陷的演变、空洞的形成以及辐照诱导晶界处溶质元素浓度的变化。实验结果表明 :He能促进两类合金空洞核心的增加 ,但空洞尺寸和密度不同 ;He能有效抑制辐照诱起晶界元素偏析 ,但对不同原子尺寸的溶质原子抑制效果不同。该差别是由于He的注入提高空位移动激活能和改变点缺陷与溶质原子相互作用的效果