Synthesis and characterization of cellulose/silver nanocomposites from bioflocculant reducing agent.

Microbial secreted polymers have high molecular weight due to the presence of repeated units of macromolecules. Some of the polymers are derived from natural resources, including marine and soil microorganisms. In nano-biotechnology people are using different biological agents in the preparation of metal nanoparticles. In this study, the microbial bioflocculant polymer was used as an agent in preparation of silver nanoparticles. The prepared nanoparticles were immobilized into the cellulose matrix. The presence of silver nanoparticles inside the cellulose matrix was confirmed by Scanning Electron Microscopic (SEM) and Transmission Electron Microscopic (TEM) analyses. The FTIR characterization studies revealed the presence of silver in the cellulose nanocomposites. The XRD analysis indicated the silver peak formation inside the silver nanocomposites. The thermal degradation studies of silver nanocomposites showed that at 450°C the residual weight was completely decreased. The antibacterial activity of silver nanocomposites was tested against E.Coli bacteria.

Identification and production of bioflocculants by Enterobacter sp. and Bacillus sp. and their characterization studies.

In this work, two bioflocculants, namely, EB-EPS and B1-EPS, were derived from Enterobacter sp. and Bacillus sp., respectively, and analyzed with regard to their production and characterization. About 0.9 and 0.16 g of purified EB and B1 were obtained from I L of fermentation broth. Chemical analysis showed the contents of purified EB and B1 mainly as 88.7 and 92.8% (w/w) of carbohydrate, and 11.3 and 21.8% (w/w) protein, respectively. Fourier-transform infrared spectrometry analysis revealed the presence of hydroxyl, amide, and carboxyl groups in the identified bioflocculant. Thermogravimetric analysis (TGA) results exhibited enhanced thermal stability with a minimum mass loss of 50% while 25% were found to have occurred at higher temperatures (>400°C) for microbe-derived compounds EB and B1 leading to the possibility of using these compounds as fillers or for fabricating composite films for high-temperature applications. Further, the compounds from both the bacteria exhibited good antibacterial characteristics against pathogenic Escherichia coli. Degradability study of bioflocculant-embedded composite films shows the possibility of attaining eco-friendly bioremediation. Accordingly, experimental results revealed the suitability of developed composite films as a suitable alternative for food packaging and biomedical applications.

Preparation and properties of cellulose nanocomposite films with in situ generated copper nanoparticles using Terminalia catappa leaf extract.

In the present work, copper nanoparticles (CuNPs) were in situ generated inside cellulose matrix using Terminalia catappa leaf extract as a reducing agent. During this process, some CuNPs were also formed outside the matrix. The CuNPs formed outside the matrix were observed with transmission electron microscope (TEM) and scanning electron microscope (SEM). Majority of the CuNPs formed outside the matrix were in the size range of 21-30nm. The cellulose/CuNP composite films were characterized by Fourier transform infrared spectroscopic, X-Ray diffraction and thermogravimetric techniques. The crystallinity of the cellulose/CuNP composite films was found to be lower than that of the matrix indicating rearrangement of cellulose molecules by in situ generated CuNPs. Further, the expanded diffractogram of the composite films indicated the presence of a mixture of Cu, CuO and Cu2O nanoparticles. The thermal stability of the composites was found to be lower than that of the composites upto 350°C beyond which a reverse trend was observed. This was attributed to the catalytic behaviour of CuNPs for early degradation of the composites. The composite films possessed sufficient tensile strength which can replace polymer packaging films like polyethylene. Further, the cellulose/CuNP composite films exhibited good antibacterial activity against E.coli bacteria.

Oxygen cycling in conjunction with stem cell transplantation induces NOS3 expression leading to attenuation of fibrosis and improved cardiac function.

AIMS: Myocardial infarction (MI) is associated with irreversible loss of viable cardiomyocytes. Cell therapy is a potential option to replace the lost cardiomyocytes and restore cardiac function. However, cell therapy is faced with a number of challenges, including survival of the transplanted cells in the infarct region, which is characterized by abundant levels of oxidants and lack of a pro-survival support mechanism. The goal of the present study was to evaluate the effect of supplemental oxygenation on cell engraftment and functional recovery in a rat model. METHODS AND RESULTS: MI was induced in rats by a 60-min occlusion of the coronary artery, followed by restoration of flow. Mesenchymal stem cells (MSCs), isolated from adult rat bone marrow, were transplanted in the MI region. Rats with transplanted MSCs were exposed to hyperbaric oxygen (HBO: 100% O(2), 2 atmospheres absolute) for 90 min, 5 days/week for 4 weeks. The experimental groups were: MI (control), Ox (MI + HBO), MSC (MI + MSC), and MSC + Ox (MI + MSC + HBO). HBO exposure (oxygenation) was started 3 days after induction of MI. MSCs were transplanted 1 week after induction of MI. Echocardiography showed a significant recovery of cardiac function in the MSC + Ox group, when compared with the MI or MSC group. Oxygenation increased the engraftment of MSCs and vascular density in the infarct region. Molecular analysis of infarct tissue showed a four-fold increase in NOS3 expression in the MSC + Ox group compared with the MI group. CONCLUSIONS: The results showed that post-MI exposure of rats to daily cycles of hyperoxygenation (oxygen cycling) improved stem cell engraftment, cardiac function, and increased NOS3 expression.

Assessment of groundwater quality in Virudhunagar district (India): a statistical approach.

The present work was undertaken to analyze the various water quality parameters, viz. pH, electrical conductivity, total dissolved solids, total alkalinity, total hardness, Cl-, SO4(2-), Ca2+, Mg2+, Na+ and K+ and study the WQI in bore well and dug well water samples. 30 water samples were collected from different localities of Virudhunagar district, Tamil Nadu (India). The results were compared with the values stipulated by World Health Organization (WHO), Indian Council of Medical Research (ICMR) and European Economic Community (EEC) for drinking water quality. The present study showed the overall water quality of Virudhunagar district is poor and unsuitable for drinking purpose which recommends the use of indigenous technologies, to make water fit for drinking purpose.