Time‐dependent dosing of Fe2+ for improved lipopeptide production by marine Bacillus megaterium

BACKGROUND: Lipopeptide production is strongly influenced by trace metals. The availability of free Fe²⁺ in the media throughout the process of fermentation was found to be very critical. Since free Fe²⁺ was reported to be sequestered by the lipopeptide as it was produced, intermittent feeding of Fe²⁺ was strategized and optimized for enhanced lipopeptide production by marine Bacillus megaterium in glucose mineral salts medium (GMSM). RESULTS: Studies with the single‐dose Fe²⁺ (0.48 mmol L^?1) supplementation after 8 h of fermentation resulted in lipopeptide concentration of 3.3 ± 0.1 g L^?1. Lipopeptide production was further enhanced to 4.2 ± 0.15 g L^?1 by adopting a multi‐dose Fe²⁺ feeding strategy. The maximum product yield (Y_P/S) of 0.24 ± 0.02 g g^?1 with specific product formation rate (q_p) of 0.124 ± 0.01 g g^?1 h^?1 was achieved when 0.48 mmol L^?1 Fe²⁺ was fed intermittently at different times as per the designed strategy. CONCLUSION: Lipopeptide concentration was improved 4.7‐fold by single‐dosing and 5.8‐fold by multiple dosing of Fe²⁺, when compared with GMSM without Fe²⁺ supplementation. Copyright © 2012 Society of Chemical Industry     

Unidirectional growth,structural, optical and mechanical properties of LTA crystal

Nonlinear optical amino acid single crystal of l-tartaric acid was successfully grown by unidirectional Sankaranarayanan–Ramasamy method under ambient conditions for the first time. The grown single crystal was subjected to different characterization analyses in order to find out its suitability for device fabrication. The crystal system and lattice parameters were determined from the powder X-ray diffraction analysis. The crystalline perfection was evaluated using high-resolution X-ray diffractometry. It is evident from the optical absorption study that crystal has excellent transmission in the entire visible region with its lower cut off wavelength around 220 nm. The mechanical properties of the grown crystals were studied using Vickers microhardness tester.     

Crystal engineering and physicochemical properties of l-cysteine cadmium chloride (LCC) for frequency-doubling and optical limiting applications

Journal of Materials Science: Materials in Electronics - Adapting the solution growth method, l-cysteine cadmium chloride (LCC) crystal was synthesized, and by using a single-crystal X-ray...     

Examining the variation of vascular structure in digital fundus images using textural pattern

One of the most significant retinal abnormality in which an individual loses the vision is diabetic retinopathy (DR). The appropriate way to treat this disease would be easier if it is detected at an earlier stage. The study on the vasculature extracted from illumination correction on the fundus image brings the presence of diabetic retinopathy. This preprocessing involves three steps. Initially illumination and reflectance estimation is done and then illumination correction is employed and finally the clipped histogram equalization is done to preserve the brightness of the image so that the information on the retinal image may not get saturated. Here, k-means segmentation process has been done and the local binary pattern (LBP) has been calculated. The selected feature vectors are then classified by using an echo state neural network (ESNN). The proposed method has been tested on publically available database DIARETDB1 that contained 89 DR fundus images in total. The result of detecting and classifying the pathology based on vasculature study on these images yielded sensitivity of 86.46%, specificity of 80.47%, and accuracy of 96.92%.     

A review of molecular interactions in organic binary mixtures

The intention of this review article is to review the knowledge about interactions in organic binary liquid mixtures. Molecular interactions in organic binary liquid mixtures are interesting due to their extensive use in many fields of solution chemistry. The thermodynamics of component molecules present in various systems interacting are particularly interesting because they display fantastic results. Studies of different organic liquid mixtures represent the different modes of interactions prevailing in the component molecules. The number of parameters required describing the properties of a given class of mixtures increases sharply with the number of segment types involved. In recent years, the theoretical and experimental investigations of interactions between unlike molecules have been conveniently carried out using excess thermodynamic functions. The properties of liquid mixtures depend on the forces between molecules and on the nature and volume of these molecules, and change with the composition of the mixtures. This change, in turn, is reflected in the thermodynamic properties of the mixtures. The influence of significant contributions of a chemical, physical and geometrical nature that change excess thermodynamic properties is considered and explained in detail.     

Structural,Optical and Impedance Studies of Hydrothermally and Solvothermally Prepared SnO<Subscript>2</Subscript> Nanocrystallites for Conducting Electrode Application

Nanocrystalline SnO₂ powders were synthesized by hydrolysis and solvolysis of SnCl₂ followed by a fast nucleation process in Teflon lined autoclave. The as prepared samples were calcined at 400 ^°C for 4 h to attain stable phase. The X-ray diffraction pattern confirms tetragonal crystal structure for both hydrothermally and solvothermally prepared nanoparticles and the average crystallite size is calculated to be 14 and 30 nm respectively. Williamson–Hall plot (W–H plot) reveals low value of strain induced broadening using uniform deformation model. Absorption co-efficient of prepared SnO₂ was determined using UV–Visible absorption spectrum. Nyquist plane plot shows the decreased electrical resistance of SnO₂ with increasing the applied potential resulting in increased conductivity. The increasing conducting behavior of tin oxide nanoparticles can be used as conducting layer in photoelectrodes.     

Synthesis and characterization of one dimensional semiconducting nanorods and nanobelts

CdSe nanorods, nanobelts are synthesized via a simple sacrificial template assisted solvothermal route at a moderate temperature of 180°C. The influences of introducing sacrificial template, hydrazine hydrate (N₂H₄·H₂O) as the reducing agent, ammonia (NH₃·H₂O) and NaOH as the complexing agent on the morphology and size of the obtained CdSe nanorods and nanobelts are investigated and reported. CdSe nanorods with a mean diameter and length of 25 nm and 82 nm respectively are synthesized and the problem of handling the stacking faults present in the long CdSe is analyzed. The structural phase, morphology and the optical properties of CdSe nanorods and nanobelts are studied using powder X-ray diffraction, TEM/HRTEM, UV-visible absorption spectroscopy and photoluminescence (PL) spectroscopy respectively.     

Biomass estimates,characteristics, biochemical methane potential,kinetics and energy flow from Jatropha curcus on dry lands

In this study, we examined the production of Jatropha curcus plants on 1 ha of rain fed dry lands. All of the plant components that would result from plantation tending, fruit harvesting and processing were sampled for their yield and chemical composition, and then subjected to the biochemical methane potential (BMP) assay. The component parts exhibited significant variation in BMP which was reflected in their ultimate methane yield which ranged from 0.08 to 0.97 L g^?1 VS added, and their first order kinetics which ranged from 0.07 to 0.14 d^?1. We examined two integrated utilization schemes: the first which converted plant prunings, fruit hulls and de-oiled seed cake to methane, and the oil to fatty acid methyl-ester (FAME); the second was to convert the seeds, plant prunings and fruit hulls entirely to methane. The basis for the plantation was, a density of 4444 plant ha^?1 (1.5 m × 1.5 m spacing), with a seed yield of 0.911 kg TS plant^?1 (1 kg total weight) with an oil content of 35% providing an annual oil yield of 1.42 t y^?1. The corresponding yields of pruned leaves, fruit hulls and de-oiled cake are 0.97, 1.0, and 2.35 t VS ha y^?1, respectively. An integrated scheme of producing biogas by means of anaerobic digestion of the latter components and oil for biodiesel would produce 90 GJ ha^?1 y^?1 in total with the oil being 54 GJ. The alternative biogas only option which would convert the seed oil into methane instead of biodiesel would produce 97 GJ ha^?1 y^?1.     

High capacity multi-bit data hiding based on modified histogram shifting technique

A novel data hiding technique based on modified histogram shifting that incorporates multi-bit secret data hiding is proposed. The proposed technique divides the image pixel values into embeddable and nonembeddable pixel values. Embeddable pixel values are those that are within a specified limit interval surrounding the peak value of an image. The limit interval is calculated from the number of secret bits to be embedded into each embeddable pixel value. The embedded secret bits can be perfectly extracted from the stego image at the receiver side without any overhead bits. From the simulation, it is found that the proposed technique produces a better quality stego image compared to other data hiding techniques, for the same embedding rate. Since the proposed technique only embeds the secret bits in a limited number of pixel values, the change in the visual quality of the stego image is negligible when compared to other data hiding techniques.