Generation of ultraviolet radiation with wide angular tolerance in cesium lithium borate crystal

Tangential phase-matching has been realised in cesium lithium borate (CLBO) crystal for the first time for the generation of fourth harmonic (266 nm) of Nd:YAG and third harmonic (226.7 nm) of a dye laser radiation by second harmonic generation and sum-frequency mixing with the angular tolerance as large as 22 mrad and 21 mrad respectively, over one of the interacting beams. An energy conversion efficiency of 15% for fourth harmonic generation is obtained with a 5.5 mm thick crystal and with the average pump powers only 170 and 70 mW. A set of Sellmeier dispersion equations for the CLBO crystal have also been formulated.     

Metabolic Engineering of Biosynthetic Pathway for Production of Renewable Biofuels

Metabolic engineering is an important area of research that involves editing genetic networks to overproduce a certain substance by the cells. Using a combination of genetic, metabolic, and modeling methods, useful substances have been synthesized in the past at industrial scale and in a cost-effective manner. Currently, metabolic engineering is being used to produce sufficient, economical, and eco-friendly biofuels. In the recent past, a number of efforts have been made towards engineering biosynthetic pathways for large scale and efficient production of biofuels from biomass. Given the adoption of metabolic engineering approaches by the biofuel industry, this paper reviews various approaches towards the production and enhancement of renewable biofuels such as ethanol, butanol, isopropanol, hydrogen, and biodiesel. We have also identified specific areas where more work needs to be done in the future.     

Transportation of drug–gold nanocomposites by actinomyosin motor system

Nanotechnology is playing an important role in drug delivery to overcome limitations of conventional drug delivery systems in terms of solubility, in vivo stability, pharmacokinetics, and bio-distribution. The controlled transportation of drug into the cell and within the cell is a major challenge to be addressed. Cellular molecular motors have been exploited for their cargo carrying capacity for various applications including engineering and health care. Combination of nanotechnology and biomolecular motors can address some of the challenges in drug delivery. In the present study, transportation of drug nanocomposites has been demonstrated. Nanocomposites of 6-mercaptopurine and levodopa drugs (cancer and Parkinson’s disease, respectively) were prepared with gold nanoparticles (GNPs) by covalent attachment and these nanocomposites were attached to actin filaments. These nanocomposites were in-turn transported by actin filaments on myosin tracks. Characterization of drug nanocomposites formation was done by UV–Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and confocal microscopy. GNP composites of 6-mercaptopurine and levodopa were formed by sulfide and amide bond formation, respectively. Average velocity of actin filament attached to nanocomposites was found to be 3.17 and 3.89 μm/s for levodopa and 6-mercaptopurine, respectively, as compared to actin filaments with velocity of 4.0–6.0 μm/s. Three concepts have been proposed for the study of drug transportation into the cell based on polycationic complex formation, interaction of actin with cellular myosin and Biomolecular Adaptor for Retrograde Transport (BART) technology. The aspects of this study heads toward the development of an approach to utilize molecular motors for nanoscale transportation endogenously.     

Revisiting and enhancing electrochemical properties of SnO2 as anode for sodium-ion batteries

Journal of Solid State Electrochemistry - The tin oxide (SnO2) thin films have been prepared by the pulsed laser deposition (PLD) at deposition temperatures (Td) ranging from 300 to...     

Metal contamination in Sunairi Point sediment core along Karachi coast,Pakistan

Journal of Radioanalytical and Nuclear Chemistry - This paper describes the pollution level in sediment core collected from Sunairi Point of Karachi coastal area Pakistan. The sediment was...     

Tyrosinase inhibition kinetic studies of standardized extract of Berberis aristata

The stem bark and wood of Berberis aristata DC (Daruharidra) are one of the principal ingredients of traditional skin lighting and exfoliating scrub preparation in India. The standardised extract of B. aristata was screened to evaluate their in vitro antityrosinase activity and inhibition kinetics. Phytochemical and pharmacological studies were carried out with different solvent fractions of the methanol extract of B. aristata (MEBA). RP-HPLC analysis was used to determine the berberine content in extract and fractions of B. aristata. MEBA showed maximum berberine content. Extract and fractions of B. aristata contain the maximum amount of alkaloids than other constituents. In tyrosinase inhibition assay, MEBA was found to possess highest dose-dependent monophenolase and moderate diphenolase activity. The enzyme kinetic study revealed that MEBA possessed mixed type inhibition of monophenolase activity of tyrosinase. These bioactivities indicate that the MEBA has antihyperpigmentation potential in human skin.     

Extraction and characterization of cellulose single fiber from native Ethiopian Serte (Dracaena steudneri Egler) plant leaf

Biomaterials are renewable sources which are widely distributed, locally accessible, high possibility of recycling and biodegradation behavior. This investigation deals with the extraction and characterizing of new fiber obtained from Serte plant leaf that is found in Ethiopia. The physical, chemical and mechanical characters of the fiber had been tested and comparison with other plant fibers was done for the first time. Optimization of fiber extraction process has been done by varying the extraction variables like NaOH concentration, temperature and extraction time. Fibers possessing 56% cellulose content along with significant amount of hemicellulose, lignin and ash with tensile strength of 330?MPa were obtained. FTIR as well as X-ray diffraction analysis were also done to further analyze the fiber. This new plant leaf fiber can be another alternative resource in place of synthetic fibers depending on their application such as reinforcing polymer matrices.