Glucose induced in-situ reduction of chloroaurate ions entrapped in a fatty amine film: formation of gold nanoparticle-lipid composites

The formation of gold nanoparticle-lipid composite films by glucose-induced reduction of chloroaurate ions entrapped in thermally evaporated fatty amine films is described. Simple immersion of films of the salt of octadecylamine and chloroaurate ions (formed by immersion of thermally evaporated fatty amine films in chloroauric acid solution) in glucose solution leads to the facile in-situ reduction of the metal ions to form gold nanoparticles in the fatty amine matrix. The formation of gold nanoparticles is readily detected by the appearance of a violet color in the film and thus forms the basis of a possible new, gold nanoparticle-based colorimetric sensor for glucose. The formation of the fatty amine salt of chloroauric acid and the subsequent reduction of the metal ions by glucose has been followed by quartz crystal microgravimetry, Fourier transform infrared spectroscopy, X-ray photoemission spectroscopy and transmission electron microscopy measurements

Variation in viscous fingering pattern morphology due to surfactant-mediated interfacial recognition events

The study of the formation of finger-like patterns during displacement of a viscous fluid by a less viscous one is of technological importance. The morphology of the viscous-finger patterns generated is a function of many parameters such as the flow rate, difference in viscosities of the two fluids and the interfacial tension. We demonstrate herein that the morphology of patterns formed during viscous fingering in a Hele-Shaw cell during displacement of paraffin oil by aqueous solutions of the surfactant sodium dodecyl sulphate (SDS), is extremely sensitive to interfacial tension variation brought about by complexation of divalent cations with the surfactant SDS. The variation in morphology of the patterns formed has been quantified by measuring the fractal dimensions of structures formed in a radial Hele-Shaw cell as well as the average finger width in a linear Hele-Shaw cell. This technique shows promise for studying other interfacial phenomena in chemistry such as biorecognition as well as dynamic processes occurring at interfaces

Synthesis of [ 18 F]phencyclidines for glutamate receptor mapping

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90096/1/25802601150_ftp.pd

Economic liberalization and the antecedents of top management teams: evidence from Turkish 'big' business

There has been an increased interest in the last two decades in top management teams (TMTs) of business firms. Much of the research, however, has been US-based and concerned primarily with TMT effects on organizational outcomes. The present study aims to expand this literature by examining the antecedents of top team composition in the context of macro-level economic change in a late-industrializing country. The post-1980 trade and market reforms in Turkey provided the empirical setting. Drawing upon the literatures on TMT and chief executive characteristics together with punctuated equilibrium models of change and institutional theory, the article develops the argument that which firm-level factors affect which attributes of TMT formations varies across the early and late stages of economic liberalization. Results of the empirical investigation of 71 of the largest industrial firms in Turkey broadly supported the hypotheses derived from this premise. In the early stages of economic liberalization the average age and average organizational tenure of TMTs were related to the export orientation of firms, whereas in later stages, firm performance became a major predictor of these team attributes. Educational background characteristics of teams appeared to be under stronger institutional pressures, altering in different ways in the face of macro-level change

Bioconjugates of Glucose Oxidase and Gold Nanorods Based on Electrostatic Interaction with Enhanced Thermostability

Bioconjugates made up of an enzyme and gold nanorods (GNRs) were fabricated by electrostatic interactions (layer-by-layer method, LBL) between anionic glucose oxidase (GOD) and positively charged GNRs. The assembled processes were monitored by UV–Vis spectra, zeta potential measurements, and transmission electron microscopy. The enzyme activity assays of the obtained bioconjugates display a relatively enhanced thermostability behavior in contrast with that of free enzyme. Free GOD in solution only retains about 22% of its relative activity at 90 °C. Unexpectedly, the immobilized GOD on GNRs still retains about 39.3% activity after the same treatment. This work will be of significance for the biologic enhancement using other kinds of anisotropic nanostructure and suggests a new way of enhancing enzyme thermostability using anisotropic metal nanomaterials

Facile Pyrolytic Synthesis of Silicon Nanowires

One-dimensional nanostructures such as silicon nanowires (SiNW) are attractive candidates for low power density electronic and optoelectronic devices including sensors. A new simple method for SiNW bulk synthesis[1, 2] is demonstrated in this work, which is inexpensive and uses low toxicity materials, thereby offering a safe, energy efficient and green approach. The method uses low flammability liquid phenylsilanes, offering a safer avenue for SiNW growth compared with using silane gas. A novel, duo-chamber glass vessel is used to create a low-pressure environment where SiNWs are grown through vapor-liquid-solid mechanism using gold nanoparticles as a catalyst. The catalyst decomposes silicon precursor vapors of diphenylsilane and triphenylsilane and precipitates single crystal SiNWs, which appear to grow parallel to the substrate surface. This opens up possibilities for synthesizing nano-junctions amongst wires which is important for the grid architecture of nanoelectronics proposed by Likharev[3]. Even bulk synthesis of SiNW is feasible using sacrificial substrates such as CaCO(3) that can be dissolved post-synthesis. Furthermore, by dissolving appropriate dopants in liquid diphenylsilane, a controlled doping of the nanowires is realized without the use of toxic gases and expensive mass flow controllers. Upon boron doping, we observe a characteristic red shift in photoluminescence spectra. In summary, an inexpensive and versatile method for SiNW is presented that makes these exotic materials available to any lab at low cost

Phytosome-conjugated carvacrol: A novel approach for improving growth performance, intestinal morphology and economics of production in Broiler Chicken

Essential oils are plant-derived aromatic volatile oils, and they contain bioactive compounds that have been shown to improve poultry nutrition. However, considering problems associated with the solubility and bioavailability of polyphenolic compounds, the study was planned to find out the effect of the novel feed-grade delivery system, phytosomes for conjugation of plant-derived polyphenolic compound carvacrol on the growth performance of broiler chickens. The experiment was conducted, on 240 broiler chicks for a period of 6 weeks. The chicks were divided into 4 groups having 4 replicates of 15 birds each. The birds in the control group (T0) offered a standard diet as per BIS (2007) specification. Group T1 received a standard diet supplemented with Bacitracin Methylene Disalicylate (BMD) antibiotic at standard dose and group T2 received a standard diet supplemented with carvacrol essential oil @100 mg/kg feed. Group T3 received a standard diet supplemented with phytosome-conjugated carvacrol essential oil (carvacrol @16.6%) @100 mg/kg feed. The performance of all the treatment groups was assessed with respect to the different performance parameters. The supplementation of phytosome-conjugated carvacrol essential oil (carvacrol @16.6%) @ 100 mg/kg feed was found beneficial in terms of growth performance, feed efficiency, and intestinal morphometry. In terms of economics of broiler production, the results revealed that the addition of phytosome- conjugated carvacrol essential oil and carvacrol essential oil in diets was found beneficial in reducing the cost of broiler production, thereby enhancing the margin of profit in broiler production and fetching higher net profit than the control group