Effect on extracts of Stevia rebaudiana bertoni. in ethanol induced gastric ulcer by using wister rats

The sweet herb of Paraguay, Stevia rebaudiana Bertoni produces, in its leaves, just such an alternative with the added advantage that Stevia sweeteners are natural plant products. In addition, the sweet steviol glycosides have functional and sensory properties superior to those of many other high potency sweeteners. The PESR, EESR & AESR has investigated the anti ulcerogenic activity by using Wister rats in both sexes. Oral administration of petroleum ether, ethanol & aqueous extracts of S. rebaudiana (100 & 300 mg, p.o) produced a significant (

Improvement of crop and soil management practices through mulching for enhancement of soil fertility and environmental sustainability: A review

The logarithmic phase of the human population creates high food demand near the future throughout the world. On the flip side, improved crop production requires uninterrupted water irrigation. Therefore, sensible agricultural inputs are needed to overcome these concerns. New technology-based innovative agronomic research steps will boost the contemporary agriculture practices in developed and developing countries. Agricultural cropping systems could follow mulching practices as one of the best crop management practices for its water and nutrient management potential. It is primarily to accomplish healthy economic and environmental bonds. By covering the soil's surface with biodegradable resources such as organic and inorganic materials, mulching improves the physicochemical characteristics of the soil. This approach provides a favorable environment for the development of plant growth and fosters the activities of microbial communities. Additionally, it reduces the growth of weeds, manages erosion, gets rid of pesticide residue, and increases soil fertility. Mulching the soil surface has profound benefits in improving the soil moisture levels due to a reduced evaporation rate. This method is a practical agronomic entrance to reduce water scarcity and raise the chance of water conservation, notably in arid and semiarid regions. It can also boost crop security and production to meet the global food requirements. This review significantly focuses on the current influence and advantages of organic mulches for crop establishment in the agriculture sector, which can close the production gap between achievable and actual yield

DISTRIBUTION, ISOLATION AND CHARACTERIZATION OF LYTIC BACTERIOPHAGES AGAINST MULTI-DRUG RESISTANT AND EXTENDED-SPECTRUM OF β-LACTAMASE PRODUCING PATHOGENS FROM HOSPITAL EFFLUENTS

Objective: To isolate. Screen and characterize an effective phage for MDR and ESBL producing pathogenic bacterial strains.Methods: Bacteriophages were isolated from hospital effluent samples by double layer agar method. Isolated phages were propagated by liquidenrichment technique and its host range was analyzed by double layer agar method. Morphology of the isolated phages was identified by TransmissionElectron Microscope (TEM). Genomic and proteomic analysis was confirmed by electrophoresis technique.Results & Discussion: 46 bacteriophages were isolated against 20 different MDR and ESBL strains of those 7 phages (Mm81, Ec84, Ps85, En833,Sal836, Ec8ATCC and Ec8PMG) were selected for further studies. According to the host range analysis result the 7 phage has been shown narrow hostrange. The phage genomic DNA and structural proteins were analyzed. In addition to based on the TEM analysis two phages viz., Mm81 and Ec84 werebelongs to Siphoviridae and Podoviridae family respectively. Present study evaluates the extensive occurrence of phages in the hospital effluent. Inaddition, this is first report of isolation and characterization of Morganella morganii lytic phage in Tamil Nadu, India.Conclusion: The study highlights the distribution of bacteriophages in the hospital effluent and it gives the therapeutic potential of isolated phagesfor the treatment of MDR and ESBL Producing Pathogens.Keywords: Phage therapy, Transmission electron microscope, Extended-spectrum of β-lactamase, Multi-drug resistant

Pulsed-laser-ablation based nanodecoration of multi-wall-carbon nanotubes by Co–Ni nanoparticles for dye-sensitized solar cell counter electrode applications

Abstract We report here on the use of pulsed KrF-laser deposition technique (PLD) for the decoration of Multi-wall carbon nanotubes (MWCNTs) by Co–Ni nanoparticles (NPs) to form highly efficient counter electrodes (CEs) for use in Dye-sensitized solar cells (DSSC). By varying the number of laser ablation pulses (N LP = 500–60,000) of the KrF laser, we were able to control the average size of the Co–Ni NPs and the surface coverage of the MWCNTs by the nanoparticles. The PLD-based decoration of MWCNTs by Co–Ni NPs is shown to form novel counter electrodes, which significantly enhance the power conversion efficiency (PCE) of the DSSCs. Indeed, the DSSCs based on the PLD-decorated Co–Ni counter electrodes (obtained at the optimal N LP = 40,000) are shown to exhibit a PCE value as high as 6.68%, with high short circuit current (J sc = 14.68 mA/cm2) and open circuit voltage (V oc = 0.63 V). This represents a PCE improvement of ~190% in comparison to the DSSCs with pristine MWCNTs (PCE = 2.3%) and ~7.4% PCE increase than that of the conventional DSSC made with a sputtered Platinum-based counter electrode. By systematically investigating the local nanostructure of the Co–Ni decorated CEs, we found that the Co–Ni NPs layer exhibits a porous cauliflower-like morphology, of which surface roughness (RMS) is N LP dependent. Interestingly, both PCE and roughness of the Co–Ni NPs layer are found to exhibit the same N LP dependence, with a maximum located around the optimal N LP value of 40,000. This enabled us to establish, for the first time, a linear correlation between the achieved PCE of DSSCs and the local roughness of their CEs decorated by Co–Ni NPs. Such a correlation highlights the importance of maximizing the surface area of the Co–Ni coated MWCNTs on the CEs to enhance the PCE of the DSSCs. Finally, Ultra-violet Photoelectron Spectroscopy (UPS) measurements revealed a significant decrease in the local work function (Φ) of Co–Ni NPs decorated MWCNTs based CEs (at N LP = 40,000, Φ = 3.9 eV) with respect to that of either pristine MWCNTs (Φ = 4.8 eV) or sputtered-Pt (Φ = 4.3 eV) counter-electrodes. This Φ lowering of the Co–Ni/MWCNTs based CEs is an additional advantage to enhance the catalytic reaction of the redox couple of the electrolyte solution, and improve thereby the PCE of the DSSCs

critical relative indentation depth in carbon based thin films

Abstract The thin film hardness estimation by nanoindentation is influenced by substrate beyond a critical relative indentation depth (CRID). In this study we developed a methodology to identify the CRID in amorphous carbon film. Three types of amorphous carbon film deposited on silicon have been studied. The nanoindentation tests were carried out applying a 0.1–10 mN load range on a Berkovich diamond tip, leading to penetration depth-to-film thickness ratios of 8–100%. The work regained during unloading ( W e ) and the work performed during loading ( W t ) was estimated for each indentation. The trend of unload-to-load ratio ( W e / W t ) data as a function of depth has been studied. W e / W t depth profiles showed a sigmoid trend and the data were fitted by means of a Hill sigmoid equation. Using Hill sigmoid fit and a simple analytical method it is possible to estimate CRID of carbon based films

Growth by radio frequency sputtering and characterisation of rare earth doped wide bandgap oxides

The thesis reports the results of an experimental research on rare earth ion-doping effects on the structural, chemical, optical and near-infra-red photoluminescence properties of wide band gap oxide films. The aim of the work was to develop materials with good photoluminescence properties, which can be applied to increase the photovoltaic conversion efficiency of crystalline Si-based solar cells, through the increase of the most efficient and useful fraction of the solar spectrum which hits the cells, thanks to a photon frequency down-shifting process. Neodymium trivalent ion (Nd3+) was used as dopant of TiO2 and ZnO thin films. The films, with different Nd concentrations were grown onto quartz by RF plasma co-sputtering and annealed at different temperatures (400°-800°C). Different film architectures were investigated for their photoluminescence properties. Structural changes such as phase transformation from anatase to rutile, internal strain building and lattice distortion due to Nd3+ incorporation in titania, correlated with optical changes, were evidenced. Exciting titania and zinc oxide matrices with optimal Nd concentrations, with ultra-violet (UV) light energies equal to or above their gap values resulted in an efficient frequency down-shifting from UV to near-infra-red emission. The joint study of the vibrational, chemical and structural properties of the doped films allows the understanding of the excitation energy transfer process between the matrix to the ion, where self-trapped excitons can be involved. To conclude this study, the doped films were tested as down-shifter layers onto a Si-solar cell where they gave promising results. They were also tested for their photoactivity with methylene blue, showing their inhibitor effect on the photo-degradation of this organic dye molecule. Keywords: Co-Sputtering, rare earth doping, Neodymium, Titanium dioxide, Zinc oxide thin films, Photoluminescenc

Antifouling Potentials of Mangrove Rhizophora apiculata against Vibrio alginolyticus strainVBM-01

1654-1661Present study consist the antifouling properties from Rhizophora apiculata was tested against pioneering marine biofouling bacteria Vibrio alginolyticus. The Vibrio alginolyticus was found to dominant group with high population density of 160±2.0×10-5 colony forming unit which has been isolated from Mandapam coast of South India. Agar well diffusion method was used to find out the inhibition of biofilm forming bacteria through zone of inhibition. Followed by the time kill assay and anti-adhesion assay was performed by exploiting the potentials of antibiofilm activity. Preliminary phyto-chemical screening shows the alkaloids and saponins were exist in the chloroform extract of Rhizophora apiculata. Further, HPLC chromatogram shows two significant major peaks with 27.943 and 98.670 retention time. HPTLC profile was recorded with Rf value concluded the broad antifouling properties of the chloroform extracts of Rhizophora apiculata inhibit the growth of pioneering marine biofouling bacteria

Croissance par sputtering en radio-fréquence et caractérisation d'oxydes à large bande interdite dopés par de la terre rare

The thesis reports the results of an experimental research on rare earth ion-doping effects on the structural, chemical, optical and near-infra-red photoluminescence properties of wide band gap oxide films. The aim of the work was to develop materials with good photoluminescence properties, which can be applied to increase the photovoltaic conversion efficiency of crystalline Si-based solar cells, through the increase of the most efficient and useful fraction of the solar spectrum which hits the cells, thanks to a photon frequency down-shifting process. Neodymium trivalent ion (Nd3+) was used as dopant of TiO2 and ZnO thin films. The films, with different Nd concentrations were grown onto quartz by RF plasma co-sputtering and annealed at different temperatures (400-800). Different film architectures were investigated for their photoluminescence properties. Structural changes such as phase transformation from anatase to rutile, internal strain building and lattice distortion due to Nd3+ incorporation in titania, correlated with optical changes, were evidenced. Exciting titania and zinc oxide matrices with optimal Nd concentrations, with ultra-violet (UV) light energies equal to or above their gap values resulted in an efficient frequency down-shifting from UV to near-infra-red emission. The joint study of the vibrational, chemical and structural properties of the doped films allows the understanding of the excitation energy transfer process between the matrix to the ion, where self-trapped excitons can be involved. To conclude this study, the doped films were tested as down-shifter layers onto a Si-solar cell where they gave promising results. They were also tested for their photoactivity with methylene blue, showing their inhibitor effect on the photo-degradation of this organic dye molecule.Le travail de thèse a porté sur l étude des effets de dopage de couches minces d oxydes à large bande interdite par des ions de terre rare sur leur propriétés chimiques, structurelles, morphologiques, optiques et de photoluminescence dans le proche infra-rouge. Les couches dopées ont été produites par co-sputtering en radio-fréquence. Le travail a eu pour but de déveloper un matériau fonctionnel photon downshifter , susceptible d être appliqué dans le domaine de conversion photovoltaique sur des cellules solaires à base de silicium, pour en augmenter le rendement. Par ses proprietés de photoluminescence et de downshifting, ce materiau intervient dans ce processus en augmentant la fraction utile du spectre solaire incident sur la cellule. L ion trivalent du neodyme (Nd3+) a été utilisé comme dopant de couches minces de TiO2 et de ZnO, deposées avec différentes concentrations de Nd sur des substrats de quartz et recuits à différentes temperatures, entre 400C et 800C. L étude a mis en evidence des modifications structurelles, des transformation de phase, la creation de tensions mécaniques internes resultant en des distortions importantes du réseau crystallin et corrélées avec des modifications des propriétés optiques et de photoluminescence. L'excitation des matrices de TiO2 et de ZnO dopées avec des concentrations de Nd optimales, avec la radiation UV correspondant à la valeur de la bande interdite, a donné lieu à d intenses emissions dans le proche infra-rouge, grâce à un processus de transfert d energie entre la matrice et l ion Nd3+. L accés à de nombreuses techniques d analyse a permis d accéder à la compréhension du processus de transfert d énergie entre la matrice et l ion, dans lequel des excitons auto-piégés peuvent avoir un rôle. Pour conclure cette étude, les couches de TiO2 dopées ont été testées pour leur function de downshifter sur des cellules solaires à base de silicium, donnant des résultats prometteurs. En testant leur photo-activité en presence de methylène bleu, ces couches ont montré leur caractère inhibiteur de dégradation de cette molecule organique.PARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Hardness and Elastic Modulus of Neodymium-doped TiO2 films

In the present work the mechanical properties of titanium dioxide (TiO2) thin films doped with neodymium (Nd) were explored. TiO2Nd thin films were deposited by radiofrequency co-sputtering from a TiO2 and Nd targets. The chemistry was studied using Auger electron spectroscopy (AES). The mechanical properties were measured by nanoindentation. The results showed surprisingly that the incorporation of low concentration of Nd in an atomic ratio of 3.7% to Ti in the TiO2 matrix increase the hardness and elastic modulus of materials