A cellulose-based bioassay for the colorimetric detection of pathogen DNA

Cellulose-paper-based colorimetric bioassays may be used at the point of sampling without sophisticated equipment. This study reports the development of a colorimetric bioassay based on cellulose that can detect pathogen DNA. The detection was based on covalently attached single-stranded DNA probes and visual analysis. A cellulose surface functionalized with tosyl groups was prepared by the N,N-dimethylacetamide-lithium chloride method. Tosylation of cellulose was confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. Sulfhydryl-modified oligonucleotide probes complementary to a segment of the DNA sequence IS6110 of Mycobacterium tuberculosis were covalently immobilized on the tosylated cellulose. On hybridization of biotin-labelled DNA oligonucleotides with these probes, a colorimetric signal was obtained with streptavidin-conjugated horseradish peroxidase catalysing the oxidation of tetramethylbenzamidine by H2O2. The colour intensity was significantly reduced when the bioassay was subjected to DNA oligonucleotide of randomized base composition. Initial experiments have shown a sensitivity of 0.1 μM. A high probe immobilization efficiency (more than 90 %) was observed with a detection limit of 0.1 μM, corresponding to an absolute amount of 10 pmol. The detection of M. tuberculosis DNA was demonstrated using this technique coupled with PCR for biotinylation of the DNA. This work shows the potential use of tosylated cellulose as the basis for point-of-sampling bioassays.Peer reviewedFinal Accepted Versio

Linear Stability of Double Diffusive Convection of Hadley-prats Flow with Viscous Dissipation in a Porous Media

Linear stability analysis of double diffusive convection in a horizontal fluid saturated porous layer has been carried out. Effects of viscous dissipation, horizontal mass flow are taken into account. Combined effects of horizontal mass flow, viscous dissipation may cause instability in the fluid system. To carry out linear stability analysis, disturbances are the form of longitudinal rolls, transverse rolls have been considered. In order to solve eigenvalue problem numerically, Runge-Kutta and shooting methods have been employed for the case of longitudinal rolls. Chebyshev-Tau method has been used for the case of transverse rolls. Critical wave number a(C), critical vertical thermal Rayleigh number Ra-C are evaluated for assigned values of flow governing parameters. For the onset of convection, physical explanation is given

Translocation and enrichment of heavy metals in Brassica juncea grown in Paper mill effluent irrigated soil

The present study observed the accumulation of heavy metals in Brassica juncea irrigated with paper mill effluent (PME) and control Bore well water (BWW). The soil was treated to five rates of effluents viz. 10, 25, 50, 75 and 100 ml/Kg soil. It was revealed 100% PME irrigation of soil increased Pb (+46.44%), Cr (+83.21%), Ni (+38.43%) and Cd (+78.92%). The enrichment factor (Ef) for Cr and Cd showed moderate enrichment with 10% to 75% PME irrigated soil, except Cr (5.96) which showed significant enrichment with 100% PME irrigated soil. Ef value for Pb and Ni showed deficiency to mineral enrichment with different concentrations of PME irrigated soil. The maximum accumulation of Pb (42.66±2.05 mg/kg), Cr (39.80±5.95 mg/kg), Ni (88.64±11.29 mg/kg) and Cd (5.85±0.29 mg/kg) were recorded in leaves of B. juncea, while that of Pb (43.85±3.46 mg/kg), Cr (48.59±3.81 mg/kg), Cd (6.74±1.22 mg/kg) with 100% and Ni (74.93±2.54 mg/kg) were recorded with 75% PME after 60 days in roots of the B. juncea. Ef value was found maximum for Cr (5.08) in leaves and for Pb (6.64) in roots, while the Translocation factor (Tf) was found maximum for Pb (2.45) in root of the crop irrigated with PME. The use of PME with proper dilution and with the metallic concentrations in permissible limit can be used as biofertigant for irrigation of B. juncea

Cortical lamina technique: a therapeutic approach for lateral ridge augmentation using guided bone regeneration

The present study aimed at evaluating the efficacy of a novel technique, the bone lamina technique, in horizontal ridge augmentation clinically & radiographically using a combination of allogenic cortical shell, particulate xenograft and resorbable collagen membrane. Localized horizontal ridge defects, in ten patients (6 male, 4 female), with bucco-palatal ridge width less than 5 mm were included in this study. Localised ridge augmentation was performed using bone lamina technique with mineralised allogenic shell of 1 mm thickness trimmed to the appropriate size using stereo-lithographic models and fixed to the recipient site with stainless steel micro-screws of 1 mm diameter. The space between the shell & host bone was filled with particulate xenograft followed by placement of collagen membrane and primary closure of the site. Clinical parameters including ridge width before & after flap reflection & radiographic (CBCT) ridge width measurements were recorded pre-operatively,and six months after the augmentation procedure. Results obtained were analysed statistically. The mean clinical ridge width before flap reflection (BFR), after flap reflection (AFR) & radiographically was 3.7 ± 0.74 mm, 2 ± 0.70 mm & 1.77 ± 0.71 mm respectively at baseline which increased to 6.8 ± 0.95 mm, 5.15 ± 0.98 mm & 4.90 ± 0.90 mm with a mean gain in ridge width of 3.1 ± 0.63 mm (p< 0.005), 3.15 ± 0.63 mm (p<0.005) & 3.13 ± 0.70 mm (p< 0.005) respectively. The present study demonstrates that bone lamina technique can be effective means of horizontal ridge augmentation and the use of mineralized allograft in combination with xenograft and collagen membrane leads to good amount of bone regeneration for subsequent implant placement

Stack Contention-alleviated Precharge Keeper for Pseudo Domino Logic

The dynamic circuits are supposed to offer superior speed and low power dissipation over static CMOS circuits. The domino logic circuits are used for high system performance but suffer from the precharge pulse degradation. This article provides different design topologies on the domino circuits to overcome the charge sharing and charge leakage with reference to the power dissipation and delay. The precharge keeper circuit has been proposed such that the keeper transistors also work as the precharge transistors to realize multiple output function. The performance improvement of the circuit\u27s analysis have been done for adders and logic gates using HSPICE tool. The proposed keeper techniques reveal lower power dissipation and lesser delay over the standard keeper circuit with less transistor count for different process variation