Molten Glass Corrosion Resistance of Immersed Combustion-Heating Tube Materials in E-Glass

The corrosion resistance of molybdenum, molybdenum disilicide, and a SiC_{( p )}/Al₂O₃ composite to molten E-glass at 1550^deg;C was studied. Mo showed no tendency to oxidize as it was immersed in soda-lime silicate glass in a parallel study. MoSi₂ was corroded by soluble molecular oxygen, leaving a Mo₅Si₃ interface behind. The SiC_{( p )}/Al₂O₃ composite was corroded at a more rapid rate wherein the SiC component was oxidized to form amorphous silica and CO bubbles. Based on these results, the activity of soluble molecular oxygen in E-glass was determined to be in the range of 2.4 × 10^-14 to 2.0 × 10^-8.     

India's trade-related aspects of Intellectual Property Rights compliant pharmaceutical patent laws: what lessons for India and other developing countries?

India's trade-related aspects of Intellectual Property Rights (TRIPS) compliant Patent (Amendment) Act 2005 saw the transformation of its laws from a process patent regime to a product patent regime. The amendments have had a direct impact on India's generic drugs manufacturing sector, which was developed through the process patent regime introduced under the 1970 Act. The knock-on effect will soon be felt both domestically and globally, as a number of developing countries have come to rely strongly on Indian generics. This article seeks to study the effectiveness of the Act of 2005, and if it can be seen as an instance of success of the TRIPS provisions in Articles 7 and 8 read along with the Doha Declaration. It will be queried if developing countries in the World Trade Organization can possibly benefit from the model set-up by India for the issuance of compulsory licenses, and to check the practice of ‘evergreening’ by pharmaceutical patent holders. Recent decisions from the Indian judiciary and the quasi-judicial authorities, along with the procedures and policies put in place will be used to carry out the study.     

Reformulation of FCC gasoline

FCC gasoline obtained from an Indian refinery was analyzed for its quality improvement through catalytic processes. The analysis indicated the presence of high amount of sulfur, olefin and iso-paraffins in the feed that are not suitable for processing through the hydro treatment or hydro-isomerization. Detailed studies indicated that majority of iso-paraffinic and olefinic compounds in the feed boil below 60 °C. The entire range of gasoline is fractionated into light fraction (IBP-60 °C) and heavy fraction (60 °C-FBP). Heavy hydrocarbon fraction exhibited more aromatics and sulfur with comparatively low olefins and iso-paraffins. HDS followed by hydro-isomerization of the heavier fraction resulted in the formation of C₆-C₉ iso-paraffins through the saturation of olefins and aromatics. Overall, the processed FCC gasoline exhibited more iso-paraffins with low olefins, low aromatics and sulfur, without any loss in octane number.     

Ultra high aspect ratio penetrating metal microelectrodes for biomedical applications

Studying the functioning of the brain through the use of penetrating microelectrodes has revolutionized our understanding of the brain and has the potential to treat physical conditions such as the aftermath of a stroke, disease or other neural problems. Cochlear implant electrodes have transformed the lives of people who were suffering from cochlear auditory disorders. However, limitations of manufacturing procedures restrict the choice of work materials to mostly silicon based materials, and biocompatibility issues have constrained the extensive use of these devices. Metal microelectrodes can absolve this limitation and enable extensive study of the neural centers. In this paper we report the fabrication of tungsten penetrating microelectrodes using electrochemical machining. Ultra high aspect ratio penetrating metal microelectrodes with diameters 10 μm and below, with surface roughness (Ra) values in the range of 300–500 nm, have been fabricated by electrochemical machining process. Details regarding the fabrication process and a mathematical model developed for the electrochemical machining process are discussed in this paper.     

Light-Control over Casein Kinase 1δ Activity with Photopharmacology: A Clear Case for Arylazopyrazole-Based Inhibitors

Protein kinases are responsible for healthy cellular processes and signalling pathways, and their dysfunction is the basis of many pathologies. There are numerous small molecule inhibitors of protein kinases that systemically regulate dysfunctional signalling processes. However, attaining selectivity in kinase inhibition within the complex human kinome is still a challenge that inspires unconventional approaches. One of those approaches is photopharmacology, which uses light-controlled bioactive molecules to selectively activate drugs only at the intended space and time, thereby avoiding side effects outside of the irradiated area. Still, in the context of kinase inhibition, photopharmacology has thus far been rather unsuccessful in providing light-controlled drugs. Here, we present the discovery and optimisation of a photoswitchable inhibitor of casein kinase 1δ (CK1δ), important for the control of cell differentiation, circadian rhythm, DNA repair, apoptosis, and numerous other signalling processes. Varying the position at which the light-responsive azobenzene moiety has been introduced into a known CK1δ inhibitor, LH846, revealed the preferred regioisomer for efficient photo-modulation of inhibitory activity, but the photoswitchable inhibitor suffered from sub-optimal (photo)chemical properties. Replacement of the bis-phenyl azobenzene group with the arylazopyrazole moiety yielded a superior photoswitch with very high photostationary state distributions, increased solubility and a 10-fold difference in activity between irradiated and thermally adapted samples. The reasons behind those findings are explored with molecular docking and molecular dynamics simulations. Results described here show how the evaluation of privileged molecular architecture, followed by the optimisation of the photoswitchable unit, is a valuable strategy for the challenging design of the photoswitchable kinase inhibitors.     

Arsenic sorption on TiO2 nanoparticles: Size and crystallinity effects

Single solute As (III) and As (V) sorption on nano-sized amorphous and crystalline TiO₂ was investigated to determine: size and crystallinity effects on arsenic sorption capacities, possible As (III) oxidation, and the nature of surface complexes. Amorphous and crystalline nanoparticles were prepared using sol-gel synthesis techniques. For amorphous TiO₂, solute pH in the range of 4-9 had a profound impact on only As (V) sorption. As (III) and As (V) sorption isotherms indicated that sorption capacities of the different TiO₂ polymorphs were dependent on the sorption site density, surface area (particle size) and crystalline structure. When normalized to surface area, As (III) surface coverage on the TiO₂ surface remained almost constant for particles between 5 and 20 nm. However, As (V) surface coverage increased with the degree of crystallinity. X-ray absorption spectroscopic analysis provided evidence of partial As (III) oxidation on amorphous TiO₂ rather than crystalline TiO₂. The data also indicated that As (III) and As (V) form binuclear bidentate inner-sphere complexes with amorphous TiO₂ at neutral pH.     

Hydrogen diffusivity in Aermet 100 at room temperature under galvanostatic charging conditions

The diffusivity of hydrogen at room temperature in an ultra high strength steel Aermet^® 100 was studied using a variety of techniques, such as an electrochemical method, sub-surface microhardness profiling, quantitative depth profiling using nuclear reaction analysis (NRA) and nanohardness profiling. Aermet^® 100 samples were cathodically charged under a galvanostatic condition at a current density of 10 A/m². The electrochemical technique was used to determine the diffusivity of hydrogen in the Aermet^® 100 cathode by monitoring the potential as a function of time. These results were compared with diffusivity data extracted from sub-surface microhardness profiling. Independently, nanohardness depth profiling was carried out to validate the hardness data near the surface. Excellent correlations were obtained in the data for hydrogen diffusivity from each of these techniques. The room temperature hydrogen diffusivity in Aermet^® 100 was measured at approximately 2.91×10⁻¹³ m²/s. NRA indicated that the near-surface concentration of hydrogen under the electrolytic charging conditions utilized was about 5 at.%.     

Stimulation of bile acid synthesis by dibutyryl cyclic AMP in isolated rat hepatocytes

Freshly isolated rat hepatocytes were used to examine the effects of dibutyryl cyclic AMP on the incorporation of¹⁴C-acetate and¹⁴C-cholesterol into bile acids. After an initial lag period, both precursors were incorporated into cholic and chenodeoxycholic acids at a linear rate for the subsequent 60 min. An apparent stimulation of bile acid formation from¹⁴C-acetate by dibutyryl cyclic AMP was complicated by the concomitant inhibition of cholesterol synthesis. In experiments with¹⁴C-cholesterol, dibutyryl cyclic AMP (1 mM) increased the labeled cholic and chenodeoxycholic acids in the medium by 83 and 224%, respectively, but cellular levels of labeled bile acids were unchanged. As a result, the nucleotide stimulated the overall incorporation of¹⁴C-cholesterol into cholic acid by 39% and into chenodeoxycholic acid by 123%. The mean ratio of labeled cholic to chenodeoxycholic acid declined from 55∶45 in control cells to 41∶59 in cells incubated with dibutyryl cyclic AMP. The results demonstrate that label incorporation can be used to study the regulation of bile acid synthesis in isolated hepatocytes. We propose that dibutyryl cyclic AMP enhances bile acid production by phosphorylating, and thus stimulating the activity of, cholesterol 7α-hydroxylase, the rate-limiting enzyme in bile acid synthesis.