In situ generation of turbostratic nickel hydroxide as a nanozyme for salivary glucose sensor.

Among the 3d-transition metal hydroxide series, nickel hydroxide is a well-studied electroactive catalyst. In particular, nickel hydroxide and its composite materials are well-suited for non-enzymatic glucose sensing. The electrocatalytic efficiency of nickel hydroxide is attributed to the thickness or to be precise, the thinness of the electroactive layer. Herein, we have successfully prepared metallic nickel@nickel hydroxide nanosheets through a straightforward one-pot solvothermal method. We were able to electrochemically generate a highly sensitive α-Ni(OH)2 on the nanosheets. The dynamic generation and synergy between α- and ß-Ni(OH)2, imparts a glucose oxidase enzyme-like ability to the catalyst. Our proposed nickel nanozyme exhibits a good sensitivity of 683 µA mM-1 cm-2 for glucose. The sensor operates in the range of 0.001-3.1 mM, with a lower limit of detection (LOD) of 9.1 µM and exhibits a response time of ≈00.1 s. Nickel-nanozyme demonstrated better selectivity for glucose in the presence of interfering compounds. Notably, the sensor does not suffer from an interfering oxygen evolution reaction. This greatly improves sensitivity in glucose detection in lower concentrations making the sensor viable to measure salivary glucose levels. In this study, we demonstrate that our sensor can detect glucose in human saliva. The real sample analysis was carried out with saliva samples from three healthy human volunteers and one prediabetic volunteer. Our proposed sensor measurements show excellent agreement with calculated salivary glucose levels with 98% accuracy in sensing glucose in real saliva samples.

A Simple Modified Technique for In-Situ Screw Fixation in Slipped Capital Femoral Epiphysis.

BACKGROUND: In-situ pinning has a definite role in the management of slipped capital femoral epiphysis (SCFE). We describe a modified technique for in-situ screw fixation on a regular radiolucent operating table which avoids certain complications innate with the existing techniques. MATERIALS: Sixty consecutive hips which underwent either in-situ fixation for SCFE (28 hips) or prophylactic fixation of the contralateral hip (32 hips) by the modified technique were analysed. The femoral head was divided into three zones (A-central, B-middle, C-peripheral) of equal circles. The zone of the screw was noted in both AP and lateral views. The angle between the physeal line and the screw in AP(SAP) and lateral (Slat) view, and the distance from screw tip to articular surface in both views were measured. RESULTS: In AP view, 55/60 (91.6%) screws were in zone-A, and five were in zone-B. In the lateral view, 56/60 (93.3%) screws were in zone-A, and four were in zone-B. There was no screw placed in zone-C in either of the views. The average deviation was < 15° in AP view and < 7° in lateral view from the ideal placement. The mean distance from the screw tip to the articular margin in AP was 5.15 mm and that in lateral was 6.15 mm. The interobserver agreement rate was found to be 0.8. No patient had intraoperative breakage of a drill bit or joint penetration, avascular necrosis, chondrolysis or screw-related complications at a minimum follow-up of one year. CONCLUSION: In-situ pinning on the radiolucent table is safe and has distinct advantages. The modified technique of in-situ screw fixation adds to the safety and accuracy of the procedure. LEVEL OF EVIDENCE: Level IV.

Is the Acetabulum Retroverted in SCFE? A Study of Acetabular Morphology in Indian Children with SCFE.

BACKGROUND: Acetabular morphology has always been an area of interest in patients with slipped capital femoral epiphysis (SCFE). Acetabular retroversion in SCFE is proposed as a pre-disposing factor and also can predispose the hip to pincer impingement. But there is controversial data in literature regarding the acetabular morphology. All available data are from the West and we present the first study on acetabular morphology in Indian children with SCFE. METHODS: CT scans of 29 patients with SCFE were collected from our database and anteversion was measured as described by Dandachli et al. Lateral central edge angle (LCEA) was measured in the standard AP radiographs of the pelvis. There were 20 boys and 9 girls with a mean age of 13.5. Seven patients had right side SCFE, eighteen had left side SCFE, and four had bilateral involvement. Measurements were done in 33 affected hips and compared with 25 normal hips. RESULTS: The mean AVsup and AVcen of affected hips were 6.59° and 13.51°, respectively, and that in normal hips were 8.36° and 14.04° (p > 0.05). The mean LCEA was 23.05° on the affected hips and 25.45° on the normal hips (p > 0.05). The AVsup showed retroversion in 24.24% (8/33) of the affected hips and 20% (5/25) of the normal hips. Though the mean version was less in SCFE hips, it was not statistically significant. CONCLUSION: Our study documents that 25% of hips with SCFE had acetabular retroversion. However, this was not significantly high compared to the contralateral hips.

Effect of immune gene silencing in WSSV infected tiger shrimp Penaeus monodon.

White spot syndrome virus, continues to cause huge economic loss to aquaculture industry. In the absence of effective therapeutics to control WSSV, it is important to understand the host pathogen interaction at the molecular level. Suppression subtractive hybridization (SSH) cDNA library was constructed which led to identification of several differentially expressed genes in response to WSSV infection in Penaeus monodon. The genes expressed in SSH cDNA library of shrimp gill and gut tissues belonged to a wide range of biological functions. The three differentially expressed genes, Single von Willebrand factor type C domain protein (pmSVC), P53 protein gene (pmP53) and ADP ribosylation factor (pmArf) were up-regulated against WSSV infection and were further characterized by gene silencing to study the role of these shrimp immune genes on WSSV multiplication. The sequence-specific knock down of pmSVC, pmP53 and pmArf using the dsRNA revealed that in pmSVC-dsRNA inoculated shrimps WSSV replication was more with increased viral copy numbers when compared with pmP53-dsRNA and pmArf -dsRNA inoculated shrimps. The varied response of immune genes to WSSV infection, indicated that host genes may either inhibit virus replication to some extent or might act as a target to facilitate viral pathogenesis.

Gene expression profiling in gill tissues of White spot syndrome virus infected black tiger shrimp Penaeus monodon by DNA microarray.

White spot syndrome virus (WSSV) continues to be the most devastating viral pathogen infecting penaeid shrimp the world over. The genome of WSSV has been deciphered and characterized from three geographical isolates and significant progress has been made in developing various molecular diagnostic methods to detect the virus. However, the information on host immune gene response to WSSV pathogenesis is limited. Microarray analysis was carried out as an approach to analyse the gene expression in black tiger shrimp Penaeus monodon in response to WSSV infection. Gill tissues collected from the WSSV infected shrimp at 6, 24, 48 h and moribund stage were analysed for differential gene expression. Shrimp cDNAs of 40,059 unique sequences were considered for designing the microarray chip. The Cy3-labeled cRNA derived from healthy and WSSV-infected shrimp was subjected to hybridization with all the DNA spots in the microarray which revealed 8,633 and 11,147 as up- and down-regulated genes respectively at different time intervals post infection. The altered expression of these numerous genes represented diverse functions such as immune response, osmoregulation, apoptosis, nucleic acid binding, energy and metabolism, signal transduction, stress response and molting. The changes in gene expression profiles observed by microarray analysis provides molecular insights and framework of genes which are up- and down-regulated at different time intervals during WSSV infection in shrimp. The microarray data was validated by Real Time analysis of four differentially expressed genes involved in apoptosis (translationally controlled tumor protein, inhibitor of apoptosis protein, ubiquitin conjugated enzyme E2 and caspase) for gene expression levels. The role of apoptosis related genes in WSSV infected shrimp is discussed herein.

Nanostructured Materials Prepared by Surface-Assisted Reduction: New Catalysts for Methane Oxidation.

Cerium formate hollow spheres and cerium hydroxycarbonate nanorods with residual formate groups are effective for reducing palladium(II) salts onto their surfaces. Calcination of the new materials obtained by this surface-assisted reduction method gives highly active PdO/CeO2 nanostructures with Pd well dispersed on the substrate. Temperature-programmed oxidation experiments showed that these nanomaterials are good catalysts for the low-temperature oxidation of methane, with 50% conversion temperatures (T(50%)) at ∼300 °C.

Interaction of inorganic nanoparticles with graphene.

The changes in the electronic and magnetic properties of graphene induced by interaction with semiconducting oxide nanoparticles such as ZnO and TiO(2) and with magnetic nanoparticles such as Fe(3)O(4), CoFe(2)O(4), and Ni are investigated by using Raman spectroscopy, magnetic measurements, and first-principles calculations. Significant electronic and magnetic interactions between the nanoparticles and graphene are found. The findings suggest that changes in magnetization as well as the Raman shifts are directly linked to charge transfer between the deposited nanoparticles and graphene. The study thus demonstrates significant effects in tailoring the electronic structure of graphene for applications in futuristic electronic devices.

Novel nanocomposites made of boron nitride nanotubes and a physical gel.

This article describes successful incorporation of multiwalled boron nitride nanotubes (BNNTs) and various functionalized BNNTs by Lewis bases such as trioctylamine (TOA), tributylamine (TBA), and triphenylphosphine (TPP), etc., in organogels formed by triphenylenevinylene (TPV)-based low molecular weight gelator (LMWG) in toluene and consequent characterization of the resulting gel nanocomposites. Functionalized BNNTs were synthesized first, and the presence of tubular structures with high aspect ratio and increased diameter compared to the starting BNNTs was confirmed by SEM, TEM, and Raman spectroscopy. The micrographs of composites of 1 and BNNTs showed evidence of wrapping of the gelator molecules on to the BNNT surface presumably brought about by pi-pi stacking and van der Waals interactions. This leads to the formation of densely packed and directionally aligned fibrous networks. Such "reinforced" aggregation of the gelator molecules in presence of doped BNNTs led to an increase in the sol-to-gel transition temperature and the solidification temperature of the gel nanocomposites as revealed from differential scanning calorimetry. Rheological investigations of the gel nanocomposites indicate that the flow properties of the resulting materials become resistant to applied stress upon incorporation of even a very low wt % of BNNTs. Finally, the increase in thermal conductivity of the nanocomposite compared to the gelator alone was observed for the temperature range of 0-60 degrees C which may make these composites potentially useful in various applications depending on the choice and the amount of BNNT loading in the composite.

Stable dispersions of metal oxide nanowires and nanoparticles in water, dimethylformamide and toluene.

In view of the important need to generate well-dispersed inorganic nanostructures in various solvents, we have explored the dispersion of nanostructures of metal oxides such as TiO2, Fe3O4 and ZnO in solvents of differing polarity in the presence of several surfactants. The solvents used are water, dimethylformamide (DMF) and toluene. The surfactant-solvent combinations yielding the best dispersions are reported alongwith some of the characteristics of the nanostructures in the dispersions. The surfactants which dispersed TiO2 nanowires in water were polyethylene oxide (PEO), Triton X-100 (TX-100), polyvinyl alcohol (PVA) and sodium bis(2-ethylhexyl) sulphosuccinate (AOT). TiO, nanoparticles could also be dispersed with AOT and PEO in water, and with AOT in toluene. In DMF, PVA, PEO and TX-100 were found to be effective, while in toluene, only AOT gave good dispersions. Fe3O4 nanoparticles were held for long periods of time in water by PEO, AOT, PVA and polyethylene glycol (PEG), and by AOT in toluene. In the case of ZnO nanowires, the best surfactant-solvent combinations were found to be, PEO, sodium dodecyl sulphate (SDS) and AOT in water and AOT, PEG, PVA, PEO and TX-100 in DMF. In toluene, stable dispersions of ZnO nanowires were obtained with PEO. We have also been able to disperse oxide nanostructures in non-polar solvents by employing a hydrophobic silane coating on the surface.

Mycotic keratitis in Madras.

Corneal scrapings from 698 clinically suspected cases of mycotic keratitis were investigated for evidence of fungal infection. Of these, 322 were found to be positive by direct examination and/or culture. The infection was predominantly seen in the age group 21-50. Men were more frequently affected than women. Majority of the patients were either agricultural workers or out door manual labourers and 66.8% of them gave a definite history of antecedent corneal trauma due to vegetable or soil matter. Asperyllus flavus was the commonest causal agent isolated from 55 cases (17.1%), followed by A. niger (13.7%), A. fumigatus (10.9%), A. terreus (1.2%), A. glaucus (0.9%), and Pseudoallescheria boydii (0.6%). The order of occurrence of the genera of fungi isolated was Aspergillus, Acremonium, Curvularia, Fusarium, Candida, Syncephalastrum, Penicillium, Aureobasidium, Drechslera, Cladosporium, Rhizopus, Alternaria, Mucor, Pseudoallecheria and lastly Paecilomyces and Trichoderma from one case each.