Low field magnetoresistance, temperature coefficient of resistance and magnetocaloric effect in Pr2/3Ba1/3MnO3:PdO composites

Electrical resistivity, magnetoresistance (MR), temperature coefficient of resistance (TCR) and magnetocaloric effect of (1 − x) Pr_2/3Ba_1/3MnO₃:x PdO (x = 0-30 mol% PdO) composite manganites are reported here. Pristine sample Pr_2/3Ba_1/3MnO₃ (PBMO) shows two insulator-metal like transitions (T_P1 ~ 194 K and T_P2 ~ 160 K) in the electrical resistivity behavior. With PdO, T_P1 becomes sharper whereas T_P2 disappears beyond 10 mol% PdO addition. The intrinsic MR gets enhanced from 22% for the pristine sample to ~ 42% for 27% PdO sample. However, the extrinsic MR is found to decrease in the composites. The TCR also increases from a negligible value for PBMO to 8% for 25 mol% PdO sample. These features have been explained on the basis of opening of new conducting channels and decrease in spin dependent scattering and the overall decrease in electrical resistivity. The magnetic entropy change and relative cooling power (RCP) for the PBMO sample are 5.3418 J.Kg-K and 304.5428 J/Kg respectively. However, these values decrease in the composites.     

Detection and molecular characterization of Vibrio parahaemolyticus isolated from seafood harvested along the southwest coast of India

The levels of total and tdh⁺ Vibrio parahaemolyticus were estimated in 83 seafood samples from southwest coast of India by colony hybridization. Conventional enrichment and isolation technique was also used to study the prevalence. Polymerase chain reaction (PCR) was performed on bacterial cell lyates for detection of total and pathogenic V. parahaemolyticus by amplification of specific genes. Of 83 samples tested, V. parahaemolyticus could be detected in 74 (89.2%) samples and tdh⁺ V. parahaemolyticus in 5 (6.0%) samples by colony hybridization. V. parahaemolyticus was detected in 68 (81.9%) of 83 samples after 18 h of enrichment by PCR, and isolated from 63 (75.9%) of 83 samples by conventional isolation. The virulence genes tdh and trh could be detected in 8.4% and 25.3%, respectively, in the sample enrichment broths by PCR. Use of colony hybridization following enrichment to achieve sensitive detection of tdh⁺ V. parahaemolyticus in seafood was evaluated using another set of 58 seafood samples. Thirty pathogenic V. parahaemolyticus strains isolated during the study were screened by PCR for genetic markers to be specific for the detection of the pandemic clone. Results of this study suggest that the GS-PCR may serve as a reliable genetic marker for the pandemic clone of V. parahaemolyticus.     

印度旱灾和水灾的区域变化

The most important climatological feature of the South Asian region is the occur-rence of monsoons. With increasing concerns about climate change, the need to understand the nature and variability of such climatic conditions and to evaluate possible future changes becomes increasingly important. This paper deals with long-term above and below normal monsoon precipitation causing prolong meteorological droughts and floods in India. Five re-gions across India comprising variable climates were selected for the study. Apart from long-term trends for individual regions, long-term trends were also calculated for the Indian region as a whole. The results show that intra-region variability for monsoon precipitation is large and there are increasing numbers of meteorological summer droughts. Meteorological monsoon floods were found to have negative long-term trends everywhere except in the peninsular Indian region. The results overall suggest generic conclusions concerning the region-wide long-term trend of severity of monsoon droughts and floods in India and their spatial variability.     

Effect of dried guduchi (Tinospora cordifolia) leaf powder on rheological,organoleptic and nutritional characteristics of cookies

Tinospora cordifolia (Guduchi) is a shrub with various medicinal properties like, antioxidant, anti-diabetic, anti-inflammatory, antihepatotoxic, etc., and widely used in Ayurvedic preparations. Use of dried Tinospora leaf powder (DTLP) at the levels of 2.5, 5.0 and 7.5% on the rheological characteristics of wheat flour; organoleptic and nutritional characteristics of cookies was studied. Incorporation of increasing amount of DTLP from 0 to 7.5% increased farinograph water absorption, decreased dough stability; increased amylograph gelatinization temperature, decreased peak viscosity; increased hardness, decreased cohesiveness and springiness of cookie dough; decreased spread ratio and increased breaking strength of the cookies. Sensory evaluation showed that cookies incorporated with 5% DTLP were acceptable. Addition of DTLP increased the protein, dietary fiber, iron, calcium, radical scavenging activity and β-carotene contents of the cookies. The results showed the possibility of utilizing DTLP to improve the nutritional properties of cookies.     

Variable repeat regions in the genome of Vibrio vulnificus and polymorphism in one of the loci in strains isolated from oysters

Vibrio vulnificus an estuarine bacterium is associated with severe wound infections and fatal septicemia related to consumption of raw shellfish. In this study we screened the two whole genome sequences available for V. vulnificus in GenBank for the presence of variable number of tandem repeat (VNTR) regions. Five potential VNTR loci with unit repeat size ranging from 6-7 nucleotides were identified for V. vulnificus genome. One of the loci designated Vv1 was selected to detect the repeat number present in V. vulnificus strains isolated from oyster samples in India. Twenty six of the thirty samples tested were found to be highly polymorphic for the Vv1 locus. Copy numbers for the hexanucleotide motif ranged from 4-55, giving rise to a total of 17 polymorphic groups. Our analysis, shows that different genotypic variants exist in the environment and the VNTR loci studied can be used as a marker for strain discrimination and in epidemiological study of this organism.     

Visual motor control of a 7 DOF robot manipulator using a fuzzy SOM network

A fuzzy self-organizing map (SOM) network is proposed in this paper for visual motor control of a 7 degrees of freedom (DOF) robot manipulator. The inverse kinematic map from the image plane to joint angle space of a redundant manipulator is highly nonlinear and ill-posed in the sense that a typical end-effector position is associated with several joint angle vectors. In the proposed approach, the robot workspace in image plane is discretized into a number of fuzzy regions whose center locations and fuzzy membership values are determined using a Fuzzy C-Mean (FCM) clustering algorithm. SOM network then learns the inverse kinematics by on-line by associating a local linear map for each cluster. A novel learning algorithm has been proposed to make the robot manipulator to reach a target position. Any arbitrary level of accuracy can be achieved with a number of fine movements of the manipulator tip. These fine movements depend on the error between the target position and the current manipulator position. In particular, the fuzzy model is found to be better as compared to Kohonen self-organizing map (KSOM) based learning scheme proposed for visual motor control. Like existing KSOM learning schemes, the proposed scheme leads to a unique inverse kinematic solution even for a redundant manipulator. The proposed algorithms have been successfully implemented in real-time on a 7 DOF PowerCube robot manipulator, and results are found to concur with the theoretical findings.     

Fabrication and optical modulation of top-emitting yellow light polymer light-emitting diodes on the FR4 board

Top-emitting yellow light polymer light-emitting diodes (PLEDs) were fabricated on the FR4 board for future application in optical interconnects. A 100 μm thick glass plate with sputtered Ag films on the back side for light reflection was bonded to the board for smooth surface. The PLED had a structure of indium tin oxide /poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate)/phenyl substituted polypa raphenylene-vinylene/Ba/Ag and reached the brightness of 4528 cd/m² with a corresponding current efficiency of 7 cd/A. A small AC signal imposed onto a DC bias was employed to characterize the electroluminescence delay time and hole mobility in the PDY-132 super yellow films.     

Nanohexaconazole: synthesis,characterisation and efficacy of a novel fungicidal nanodispersion

Here, the authors describe a simple method to formulate the nanodispersion of hexaconazole (hexa); henceforth, referred to as nanohexaconazole (N‐hexa) that is water soluble and effective against several species of Aspergillus. Size and shape of the prepared nanocomposite was determined with high‐resolution transmission electron microscopy and field‐emission scanning electron microscopy. Nanohexaconazole structure was further confirmed by Fourier‐transform infrared spectroscopy and gas chromatography–mass spectrometry. The antifungal efficacy of nanohexaconazole (N‐hexa) was studied in vitro, compared with micronised hexaconazole (M‐hexa) at different doses (5 ppm, 10 ppm and control) against two food pathogenic fungi: Aspergillus niger (MTCC 282, MTCC 2196 and BDS 113) and Aspergillus fumigatus through poisoned food technique. A dose‐dependent significant growth inhibition was observed in nanohexaconazole (N‐hexa) treated fungal sample compared with that of micronised hexaconazole (M‐hexa). Micrographic studies for the morphological analysis of control and nanohexaconazole (N‐hexa) treated fungal samples were done, exhibited an alternation in fungal morphology. Results showed that nanohexaconazole (N‐hexa) is more efficacious than commercially available micronised hexaconazole (M‐hexa). In future nanohexaconazole (N‐hexa) could be a possible candidate for modern medical science and also reduce damage to the environment from injudicious use of pesticides.Inspec keywords: nanocomposites, nanosensors, transmission electron microscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, chromatography, mass spectra, chemical variables measurement, chemical sensorsOther keywords: fungicidal nanodispersion, N‐hexa structure, nanocomposite, high‐resolution transmission electron microscopy, field‐emission scanning electron microscopy, nanohexaconazole structure, Fourier‐transform infrared spectroscopy, gas chromatography, mass spectrometry, micronised hexaconazole, M‐hexa, food pathogenic fungi, Aspergillus niger, MTCC 282, MTCC 2196, BDS 113, Aspergillus fumigatus, poisoned food technique, pesticides     

An assessment of satellite-based agricultural water productivity over the Indian region

The preliminary analysis of agricultural water productivity (AWP) over India using satellite data were investigated through productivity mapping, water use (actual evapotranspiration (ET_a)/effective rainfall (R_eff) mapping and water productivity mapping. Moderate Resolution Imaging Spectroradiometer data was used for generating agricultural land cover (MCD12Q1 at 500 m), gross primary productivity (GPP; MOD17A2 at 1 km), and ET_a (MOD16A2 at 1 km). R_eff was estimated at 10 km using the United States Department of Agriculture soil conservation service method from daily National Oceanic and Atmospheric Administration Climate Prediction Center rainfall data. Six years’ (2007–2012) data were analysed from June to October. The seasonal AWP and rainwater productivity (RWP) were estimated using the ratios of seasonal GPP (kg C m^?2) and water use (mm) maps. The average AWP and RWP ranges from 1.10–1.30 kg Cm^?3 and 0.94–1.0 kg C m^?3, respectively, with no significant annual variability but a wide spatial variability over India. The highest AWP was observed in northern India (1.22–1.80 kg C m^?3) and lowest in western India (0.81–1.0 kg C m^?3). Large variations in AWP (0.69–1.80 kg C m^?3) were observed in Himachal Pradesh, Jammu and Kashmir, northeastern states (except Assam), Kerala, and Uttaranchal. The low GPP of these areas (0.0013–0.13 kg C m^?2) with low seasonal total ET_a (<101 mm) and R_eff (<72 mm) making the AWP high that do not correspond to high productivity but possible water stress. Gujarat, Rajasthan, Maharashtra, Madhya Pradesh, Jharkhand, and Karnataka showed low AWP (0.73–1.13 kg C m^?3) despite having high ET_a (261–558 mm) and high R_eff (287–469 mm), indicating significant scope for improving productivity. The highest RWP was observed in northern parts and Indo-Gangetic plains (0.80–1.6 kg C m^?3). The 6 years’ analysis reveals the status of AWP, leading to appropriate interventions to better manage land and water resources, which have great importance in global food security analysis.     

Enhancement of ferroelectric and piezoelectric characteristics in europium substituted SrBi2Ta2O9 ferroelectric ceramics

Europium substituted samples of compositions Sr_1 − xEu_xBi₂Ta₂O₉ were synthesized by solid-state reaction method. The prepared samples were characterized for their structural and electrical properties. X-ray analysis confirms the formation of the single-phase layered perovskite structure. The microstructural studies reveal that the average grain size increases with increase in Eu content. An increase in remanent polarization and d₃₃ values with increasing concentration of europium has been observed. The maximum 2P_r ~ 14 μC/cm² is observed in the sample with x = 0.20. The observed results have been discussed in terms of contribution from the cation vacancies introduced into the lattice structure due to donor doping.