Tungsten-doped TiO2/reduced Graphene Oxide nano-composite photocatalyst for degradation of phenol: A system to reduce surface and bulk electron-hole recombination.

Recombination of photogenerated charges is the main factor affecting the photocatalytic activity of TiO2. Here, we report a combined strategy of suppressing both the bulk as well as the surface recombination processes by doping TiO2 with tungsten and forming a nanocomposite with reduced graphene oxide (rGO), respectively. Sol-gel method was used to dope and optimize the concentration of W in TiO2 powder. UV-Vis, XPS, PL and time resolved PL spectra along with DFT calculations indicate that W6+ in TiO2 lattice creates an impurity level just below the conduction band of TiO2 to act as a trapping site of electrons, which causes to improve the lifetime of the photo-generated charges. Maximum reduction in the PL intensity and the improvement in charge carrier lifetime was observed for TiO2 doped with 1 at.% W (1W-TiO2), which also displayed the highest photo-activity for the degradation of p-nitro phenol pollutant in water. Tuning of rGO/TiO2 ratio (weight) disclosed that the highest activity can be achieved with the composite formed by taking equal amounts of TiO2 and rGO (1:1), in which the strong interaction between TiO2 and rGO causes an effective charge transfer via bonds formed near the interface as indicated by XPS. Both these optimized concentrations were utilized to form the composite rGO/1W-TiO2, which showed the highest activity in photo-degradation of p-nitro phenol (87%) as compared to rGO/TiO2 (42%), 1W-TiO2 (62%) and pure TiO2 (29%) in 180 min. XPS and PL results revealed that in the present nanocomposite, tungsten species traps the excited electron to reduce the interband recombination in the bulk, while the interaction between TiO2 and rGO creates a channel for fast transfer of excited electrons towards the latter before being recombined on the surface defect sites.

Bioactivity of albumins bound to silver nanoparticles.

The last decade has witnessed a tremendous rise in the proposed applications of nanomaterials in the field of medicine due to their very attractive physiochemical properties and novel actions such as the ability to reach previously inaccessible targets such as brain. However biological activity of functional molecules bound to nanoparticles and its physiological consequences is still unclear and hence this area requires immediate attention. The functional properties of Human Serum Albumin (HSA) and Bovine Serum Albumin (BSA) bound to silver nanoparticles (~60 nm) have been studied under physiological environment. Esterase activity, binding of drugs (warfarin and ibuprofen), antioxidant activity and copper binding by albumins was evaluated. The catalytic efficiencies of HSA and BSA diminished upon binding to silver nanoparticles. Perturbation in binding of warfarin and ibuprofen, loss of free sulphydryls, antioxidant activity and enhancement of copper binding were observed in albumins bound to nanoparticles. These alterations in functional activity of nanoparticle bound albumins which will have important consequences should be taken into consideration while using nanoparticles for diagnostic and therapeutic purposes.

Comprehensive studies on the interaction of copper nanoparticles with bovine serum albumin using various spectroscopies.

Copper nanoparticles (NPs) of average size of ~7.5nm were synthesized by chemical reduction method. Fluorescence spectroscopy in synchronous and polarization modes were used to examine the nature of interaction between Cu NPs and bovine serum albumin (BSA) at different temperatures. Fluorescence quenching results suggest that Cu NPs interact with BSA molecule through static mechanism, as inferred from the quenching of BSA fluorophore. The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) hint that the binding process occurs spontaneously by involving hydrophobic forces. Synchronous fluorescence spectra reveal that the interaction of Cu NPs with BSA mostly changes the microenvironment of tryptophan and not of tyrosine residues. The formation of BSA-Cu NPs ground state complex was also confirmed from the resonant light scattering and fluorescence polarization spectra. Circular dichroism and Raman spectra indicate that α-helicity of the BSA decreases due to the interaction with Cu NPs. It was also found that Cu NPs are located in the close proximity of BSA molecule, which transfer energy efficiently from the excited state of BSA fluorophore to the Cu NPs.

Structural characterization of enzymatically synthesized dextran and oligosaccharides from Leuconostoc mesenteroides NRRL B-1426 dextransucrase.

Leuconostoc mesenteroides NRRL B-1426 dextransucrase synthesized a high molecular mass dextran (>2 × 10(6) Da) with ~85.5% α-(1→6) linear and ~14.5% α-(1→3) branched linkages. This high molecular mass dextran containing branched α-(1→3) linkages can be readily hydrolyzed for the production of enzyme-resistant isomalto-oligosaccharides. The acceptor specificity of dextransucrase for the transglycosylation reaction was studied using sixteen different acceptors. Among the sixteen acceptors used, isomaltose was found to be the best, having 89% efficiency followed by gentiobiose (64%), glucose (30%), cellobiose (25%), lactose (22.5%), melibiose (17%), and trehalose (2.3%) with reference to maltose, a known best acceptor. The ß-linked disaccharide, gentiobiose, showed significant efficiency for oligosaccharide production that can be used as a potential prebiotic.

Optimally tolerated dose of lapatinib in combination with docetaxel plus trastuzumab in first-line treatment of HER2-positive metastatic breast cancer.

BACKGROUND: This phase IB, open-label, dose-escalation study evaluated the safety, tolerability, and optimally tolerated regimen (OTR) of lapatinib in combination with docetaxel and trastuzumab in patients with previously untreated stage IV metastatic breast cancer (MBC) tumors overexpressing human epidermal growth factor receptor 2 (HER2). PATIENTS AND METHODS: Evaluated dose regimens included lapatinib (500-1500 mg/day), docetaxel (triweekly; 60-100 mg/m²), and trastuzumab (weekly; 2 mg/kg fixed dose); prophylactic granulocyte colony-stimulating factor was included with regimens with ≥750 mg/day lapatinib. End points included OTR and safety/tolerability (primary), overall response rate (ORR), and pharmacokinetics (secondary). RESULTS: None of the patients (N = 53) experienced dose-limiting toxic effects (DLTs) at the highest dose level; thus, the OTR of lapatinib with 100 mg/m(2) docetaxel was not determined. Common adverse events included diarrhea, nausea, alopecia, fatigue, and rash; grade 3/4 (≥2 patients) were neutropenia, diarrhea, leukopenia, peripheral neuropathy, and rash. Seven patients had DLTs (cycle 1). In 45 patients with measurable disease confirmed by bone scan, investigator-assessed ORR was 31%; without bone scan, confirmation was 64%; 8 patients without measurable disease were evaluated as stable. Lapatinib/docetaxel plasma concentrations were positively associated with complete response. CONCLUSIONS: Lapatinib/docetaxel/trastuzumab is a feasible and well-tolerated treatment of untreated HER2-positive stage IV MBC. Two lapatinib/docetaxel OTR doses were recommended (1250 mg/75 mg/m²; 1000 mg/100 mg/m²). CLINICAL TRIAL NUMBER: NCT00251433.

Systematic investigation on the interaction of bovine serum albumin with ZnO nanoparticles using fluorescence spectroscopy.

Zinc oxide (ZnO) nanoparticles with average size of ~7.5nm were synthesized to investigate their interaction with bovine serum albumin (BSA) at different temperatures. Fluorescence quenching, synchronous and polarization spectroscopy along with UV-vis absorption, circular dichroism and resonance light scattering spectroscopy techniques were used to establish the interaction mechanism between ZnO and BSA. The obtained results confirmed that the ZnO nanoparticles (NPs) quench the fluorophore of BSA by forming ground state complex in the solution. The fluorescence quenching data was also used to determine binding sites and binding constants at different temperatures. The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) suggest that the binding process occurs spontaneously by involving hydrogen bond and van der Waals interactions. The synchronous fluorescence spectra reveal that the microenvironment close to both the tyrosine and tryptophan residues of BSA is perturbed and that the hydrophobicity of both the residues is increased in the presence of ZnO NPs. Resonance light scattering, circular dichroism, and fluorescence polarization spectra suggest the formation of BSA-ZnO complex and conformational changes in BSA. The calculated distance between the BSA and ZnO NPs suggests that the energy transfer from excited state of BSA to ZnO NPs occurs with high efficiency.

Conduction mechanism and gas sensing properties of CoFe2O4 nanocomposite thick films for H2S gas.

Nanocrystalline 10 wt% Ni and 0.2 wt% Sm doped CoFe(2)O(4) was prepared by sol-gel citrate method and calcined at different temperatures. The CoFe(2)O(4) nanoparticles were characterized by X-ray diffraction (XRD), electrical properties were studied by impedance analysis. The XRD of CoFe(2)O(4) shows cubic structure with grain growth of 40 nm. The ac conductivity was studied for the sample 10 wt% Ni and 0.2 wt% Sm doped CoFe(2)O(4) calcined at 650°C, at temperature range from 100 to 700°C over a wide range of frequencies from 50 Hz to 200 kHz. The result indicates that the ac conductivity depend on temperature, frequency and concentration of dopant. Nanocrystalline 10 wt% Ni and 0.2 wt% Sm doped CoFe(2)O(4) was found to be good H(2)S sensor with high sensitivity and selectivity.

Polyneuropathy and myopathy in the elderly.

Critical illness polyneuropathy and myopathy is associated with intensive care unit therapies; it is an independent predictor of mortality and will be increasingly affecting the practice of critical care. Most patients with this illness are over 50 years of age, and as our population demographics shift in favor of an aging population, physicians must be aware that this malady will have a rising incidence in the perioperative period. Intensivists, anesthesiologists, surgeons, and geriatricians/internists must remain vigilant. Here we present a concise overview of critical illness polyneuropathy and myopathy, its diagnosis, associations, and possible interventions.

Role of active nitrogen molecules in progression of septic shock.

INTRODUCTION: Active nitrogen molecules are formed as a result of cell metabolism. They are essential for cell metabolism, but when produced in excess, they contribute to the pathogenesis of several disease processes. These nitrogen molecules play an important role in vascular instability of septic shock. This study was planned to detect the role of active nitrogen molecules in the progression of septic shock. MATERIALS AND METHODS: Blood samples were collected from 118 critically ill patients admitted in ICU and from 95 healthy relatives accompanying the patients. Patients were categorized into three groups: systemic inflammatory response syndrome (n = 54), sepsis (n = 35) and septic shock (n = 29). Plasma total nitrite (nitrites and nitrates), cytokines like tumour necrosis factor-α (TNF-α) and plasma lactate were measured to assess inflammatory activity and severity of septic shock. RESULTS: High plasma levels of nitrite and nitrate (No2-/No3-) were observed in critically ill patients (mean level 78.92 µmol/l in sepsis and 97.20 µmol/l in septic shock). Mean plasma TNF-α level in sepsis was 213.50 pg/ml and septic shock was 227.38 pg/ml. CONCLUSION: Plasma No2-/No3- and TNF-α levels were high in patients with sepsis and septic shock, which increased with severity of sepsis.

Study of interaction of silver nanoparticles with bovine serum albumin using fluorescence spectroscopy.

The interaction between silver nanoparticles (SNPs) and Bovine Serum Albumin (BSA) was investigated at physiological pH in an aqueous solution using fluorescence spectroscopy. The analysis of fluorescence spectrum and fluorescence intensity indicates that SNPs have a strong ability to quench the intrinsic fluorescence of BSA by both static and dynamic quenching mechanisms. Resonance light scattering (RLS) spectra indicated the formation of a complex between BSA and SNP. The number of binding sites 'n' and binding constants 'K' were determined at different temperatures based on fluorescence quenching. The thermodynamic parameters namely ∆H°, ∆G°, ∆S° were calculated at different temperatures and the results indicate that hydrophobic forces are predominant in the SNP-BSA complex. Negative ∆G° values imply that the binding process is spontaneous. Synchronous fluorescence spectra showed a blue shift which is indicative of increasing hydrophobicity.

Silicon nanocluster prepared using ion beam mixing technique.

In this work, we present the results of modification of absorption band gap of Silicon nanoclusters (Si-nc) prepared by ion beam mixing on pre-irradiated fused silica. 30 keV Ar+ ions at fluences of 5 x 10(16) to 4 x 10(17) cm(-2) were used to create defects in fused silica glass before introducing Si atoms in the substrate. Si was introduced in the substrates by ion beam mixing using 30 keV Ar+ ions at fluence 1 x 10(17) cm(-2). From UV-Vis absorption spectra, band-gap of Si-nc has been determined for samples prepared at different ion beam-mixing parameters. The absorption edge shifts towards higher energies and size of the silicon nanoclusters decreases with an increase in ion beam fluence used for pre-mixing irradiation.

Neonatal tachycardias: an update.

This review provides an updated framework for the diagnosis and management of neonatal tachycardias.

Expression of MUC1 and MUC2 mucin gene products in Barrett's metaplasia, dysplasia and adenocarcinoma: an immunopathological study with clinical correlation.

AIMS: Changes in the histochemical characteristics of the surface epithelial mucins is the hallmark of Barrett's metaplasia. The study investigated the pattern of expression of MUC1 and MUC2 mucin gene products in Barrett's metaplasia, dysplasia and adenocarcinoma as possible indicators of increased malignant potential. METHODS AND RESULTS: Tissue sections from 51 patients with Barrett's intestinal metaplasia, nine with dysplasia (three indefinite) and 28 resected adenocarcinomas were stained with monoclonal antibodies to MUC1 and MUC2. The majority of the patients were men (70/88, 80%) who were treated over a period of 3 years. None of the patients with dysplasia or carcinoma were under surveillance at the time of presentation. All 51 biopsies with Barrett's metaplasia expressed MUC2 and MUC1 was consistently absent. Neither MUC1 or MUC2 were expressed in the dysplastic epithelium whether in its pure form (6/6) or when associated with carcinoma (26/28) (P < 0.005). Three biopsies which were initially classified as high-grade dysplasia expressed MUC1 and these turned out to be carcinomas on further investigations. MUC1 was also expressed in 12/28 (43%) of the adenocarcinomas and majority of these were poorly differentiated stage 3 tumours (P < 0.05). MUC2 was only positive in mucin-secreting carcinomas (4/28; 14%) irrespective of the tumour stage. CONCLUSION: Despite the large number of patients with Barrett's metaplasia and carcinoma, very few patients presented with dysplasia, implying that Barrett's oesophagus is a silent disease in the community presenting late as carcinoma. The study has demonstrated aberrant expression of MUC2 (an intestinal mucin) in Barrett's metaplasia and this expression is lost when the cells become dysplastic. The lack of MUC1 in dysplastic epithelium and its expression in carcinoma could be utilized as a marker which could differentiate dysplasia from carcinoma in mucosal biopsies. Furthermore, expression of MUC1 in advanced stage oesophageal cancers (as in breast cancer) suggests an unfavourable prognosis.

Exposure limits of women in hot environment.

The tolerance of six women to work in hot environments was examined under four environmental conditions from 38 to 44 degrees C dry bulb temperature and 50 to 80 per cent relative humidity, i.e., 32 to 36.5 degrees C effective temperature [ET (normal scale)] in a climatic chamber. The subjects performed bicycle ergometric work at an intensity of 50 W and the exposure duration was determined by the cardiorespiratory, body temperature and sweating responses. At the limit of tolerance, the body core temperature (Tcr) reached over 38.5 degrees C and the heart rates attained a peak level (i.e., about 172 beats/min). The total oxygen demand decreased significantly with higher environmental load, particularly beyond 33.5 degrees C ET (N). While the tolerance time decrement was evident with the higher heat stress, on an average, an increase or decrease of every liter of total oxygen demand was equivalent to a 0.8 min change in the tolerance time. As such, the women volunteers were not susceptible to heat; only in extreme hot situations beyond 33.5 degrees C ET (N), they had unacceptable levels of physiological and psychophysical reactions. Based on the distribution of tolerance time of the women in different exposure conditions, the safe exposure times were estimated, which varied from 43 min [32.0 degrees C ET (N)] to 16 min [36.5 degrees C ET (N)].

Human heat tolerance in simulated environment.

The heat tolerance of 11 male volunteers were examined under seven climatic conditions in a climatic chamber. The conditions were 38 to 49 degrees C dry bulb temperature and 45 to 80 per cent relative humidity, i.e., 32.3 to 40 degrees C effective temperature-basic [ET(B)]. The ET(B) values were equated to other heat stress indices, e.g., WBGT (Wet-bulb Globe Temperature Index) and Oxford Index. The subjects did ergometric work at an intensity of 60 per cent VO2max. The exposure durations were decided by the cardiorespiratory, body temperature and sweating responses. Of the climatic conditions studied, at 35.4, 38, 39 and 40 degrees C ET(B), the body core temperature (Tcr) reached over 39 degrees C and heart rates attained 172 to 182 beats/min, which were taken as the tolerance limit. The total oxygen demand significantly varied with the increase in environmental warmth, i.e., increase or decrease of one litre of oxygen demand was equivalent to one minute change in tolerance time. The volunteers were not susceptible to heat; only in extreme hot situations beyond 35.4 degrees C ET(B), were unacceptable levels of physiological and psychophysical reactions seen. The study suggests the acceptable and tolerable limits for human exposure in heat: (i) acceptable at 38 to 38.2 degrees C Tcr for a tolerance time of 80 to 85 min; and (ii) the tolerable limit of short duration (40-45 min) at 39 degrees C Tcr that corresponded to 31.5 and 36.5 degrees C ET(B).

Human work capacity under combined stress of work and heat.

The working capacity of young, healthy, unacclimatized men (N = 11) was studied under long-duration (8 to 9 days) exposure to combined work and heat (dry and humid). The dry (Gr A, N = 5) and humid (Gr B, N = 6) groups were exposed to 41.3 +/- 0.6 degrees C DB, 40-50% RH and 39.2 +/- 0.6 degrees C DB, 70-80% RH, respectively, for all days of exposure. The experimental protocol was divided into: (i) direct determination of maximal oxygen uptake (VO2max) by stepped increases in bicycle ergometry everyday in the morning in the initial hours before exposure to heat, after which the recovery process of oxygen debt contraction was examined; and (ii) exposure to heat in a climatic chamber for 2 h where the subjects performed two spells of ergometric work (10 to 12 min each) at a relative intensity of 50 +/- 12 to 69 +/- 11% VO2max. The average heat exposure time for Gr A was higher (108 +/- 12 min) as compared to Gr B (95 +/- 10 min), but Gr B sustained a high heat load as reflected from the high deep-body temperature maintained during the exposure. The high body temperature load of Gr B had a significant effect on the cardiorespiratory capacity, indicating an upward trend in VO2max. This was statistically significant (p < 0.05) for the first four days of exposure. Subjects of Gr B had a relatively higher working capacity compared to those in Gr A on all days. The VO2max and analysis of the fractions of oxygen debt contraction (fast and slow component) indicated that the subjects showed a better training/heat acclimatization effect under hot, humid conditions.

Family welfare programme in India: a proposal for structural change.

PIP: This paper attempts to present an alternative approach for implementing the Family Welfare Programme (FWP) at the district level in India. Since its launching in 1952, the National Family Planning Programme has gone through several stages of adjustment in terms of strategies and approaches. But by 1991, the program has failed to address the increasing population growth. Although several studies have shown that most people want to limit their family size, the program has not been able to convert their interest and desire into effective demand. There may be long term causes underlying the poor performance of FWP in India, some of which are structural in nature. Therefore, the program should be restructured and revitalized through a major shift in policy perspective if effective results are to be achieved. These can be done by 1) having a separate organization for the FWP; 2) decentralizing management of FWP with district as the nodal point; and 3) having an area specific approach with marketing strategies to generate effective demand for family planning services. The new system would be a bottom-up approach and would concentrate on providing basic maternal-child health and family planning services. Furthermore, the success of the implementation of the proposed alternative approach model will greatly depend on some policy decisions on the part of the Government. Before adopting this model on a wide scale, it would be worthwhile to implement it in a few selected districts on an experimental basis.^ieng