Concentration Of 10ppm Research Articles

Gas sensing mechanism and properties of Ce-doped SnO2 sensors for volatile organic compounds

Doping often plays a critical role in governing gas sensing properties of nanomaterials. Different levels of cerium (Ce) doped-tin oxide (SnO2) nanomaterials are synthesized by a hydrothermal method in order to improve its sensor performance. X-ray diffraction and field emission scanning electronic microscopy are employed to examine the chemical composition and microstructures. It is found that Ce4+ doping can suppress the growth of large SnO2 crystallites and assist a uniform growth of large agglomeration spheres. The gas sensing properties is also investigated. By considering a variety of volatile organic compound gas and gas concentration, 2% Ce-doped SnO2 is found to exhibit the best gas sensing properties with excellent response and fast response-recovery even at low gas concentration of 10ppm. Further comparative studies attribute this to enhanced capability of adsorbing oxygen on the surface. It is proposed that the main oxygen species on the surface of SnO2 is O2−, but O− may play a more important role in improving gas response.

Aqueous extract of Centella asiatica promotes corneal epithelium wound healing in vitro

Ethnopharmacological relevanceCentella asiatica is a traditional herbal medicine that has been shown to have pharmacological effect on skin wound healing, and could be potential therapeutic agent for corneal epithelial wound healing. Aim of the studyThis study was done to evaluate the effects of Centella asiatica on the proliferation and migration of rabbit corneal epithelial (RCE) cells in the in vitro wound healing model. Materials and methodsRCE cells were cultured with or without supplementation of Centella asiatica aqueous extract. Viability and proliferation of the RCE cells was determined by MTT assay and cell cycle was analyzed by flow cytometry. In vitro re-epithelization was studied by scratch assay and migration rate was evaluated quantitatively by image analyzer. Expression of corneal specific differentiation markers, CK12 and connexin 43, were studied via RT-PCR. ResultsIt was found that supplementation of Centella asiatica did not show any significant effect on the RCE cells proliferation at the concentration up to 500ppm, while at the concentration of 1000ppm significantly inhibited RCE cells proliferation (p<0.05). However, at the concentration up to 62.5ppm, RCE cells shows significant enhancement of migration rate compared to the control group (p<0.05). It was also found that the supplementation of Centella asiatica aqueous extract did not alter the expression of differentiation markers and cell cycle. ConclusionIn conclusion, supplementation of Centella asiatica aqueous extract at low concentrations could be useful to promote corneal epithelium wound healing.

The mixture of dicyclohexilamine and oleylamine as corrosion inhibitor for mild steel in NaCl solution saturated with CO2 under both continual immersion and top of the line corrosion

This paper presents a comprehensive method to evaluate the mixture of dicyclohexilamine and oleylamine (DCHA+OA) as corrosion inhibitor for mild steel in CO2 environment in liquid and vapor phase. Corrosion inhibitor volatile properties were investigated in order to determine if DCHA+OA can be used to control the severity of the top of the line (TLC) corrosion attack. Corrosion measurements were performed using electrochemical impedance spectroscopy, linear polarization resistance, potentiodynamic sweep measurements, as well as the electrical resistance measurements and weight loss measurements, in order to determine the inhibitive performances of dicyclohexilamine and oleylamine. In order to define surface morphological characteristics scanning electron microscopy technique was applied. The electrochemical study and weight loss measurements indicated that DCHA+OA significantly decreased the corrosion rate in liquid phase when 50 ppm of DCHA+OA was added. Scanning electron microphotographs indicated protective inhibitor film has formed on the steel surface and revealed that good protection was achieved, along with the decrease in the corrosion rate determined by weight loss and electrochemical techniques. Using electrical resistance measurements in vapor phase it was shown that concentration of 1000 ppm DCHA+OA significantly decreased the corrosion rate at the top of the line, only when it was carried there within its own foam and not due its volatility.

The influence of tetraethylorthosilicate and polyethyleneimine on the performance of polyethersulfone membranes

The effect of inorganic and organic additives in polyethersulfone (PES) membranes was investigated for the possible enhancement in ultrafiltration performances. Tetraethylorthosilicate (TEOS) and polyethyleneimine (PEI) were chosen as inorganic respective silica precursor and organic additive based on their potential to promote hydrophilicity in PES membranes. With the addition of TEOS and PEI in PES casting solution, the viscosity and hydrophilicity were increased.In addition of TEOS in PES, the SiO2 particles were homogeneously dispersed in PES matrix, a large amount of OH groups on the SiO2 particles generated, and led to an improvement in the hydrophilic property. Characterizations of membranes by FTIR and X-ray Diffraction (XRD) confirmed that the PES suffered a transform from various functional groups due to the addition of TEOS. The 40% of water permeability was found by 5% addition ion of TEOS and PEI repressively. The top surface and cross-section morphology of PES membranes changed from dense-like structure to finger-like macrovoids structure with increasing TEOS and PEI content. Protein solution separation was investigated using lysozyme and bovine serum albumin (BSA) with the concentration of 1000ppm. The observed sieving coefficient of protein decreased exponentially with increasing contents of TEOS and PEI in PES membranes.

Ação nematicida de extratos de alho, mostarda, pimenta malagueta, de óleo de mostarda e de dois produtos à base de capsainóides e alil isotiocianato sobre juvenis de Meloidogyne javanica, (treub) Chitwood, 1949, em casa de vegetação

Neves, W.S; Freitas, L.G.; Coutinho, M.M.; Giaretta-Dallemole, R.; Fabry, C.F.S.; Dhingra, O.D. &amp; Ferraz, S. Atividade nematicida de extratos botânicos de pimenta malagueta (Capsicum frutescens), mostarda (Brassica campestris) e alho (Allium sativum) sobre o nematóide das galhas, Meloidogyne javanica, em casa de vegetação. Summa Phytopathologica, v.35, n.4, p.255-261, 2009 O experimento teve como objetivo avaliar a atividade nematicida de extratos botânicos dos frutos de pimenta malagueta (Capsicum frutescens), plantas de mostarda (Brassica campestris), de bulbos de alho (Allium sativum) e óleo de mostarda sobre o nematóide das galhas, Meloidogyne javanica, em tomateiro em casa de vegetação e posteriormente comparar os extratos que apresentassem maior redução de número de galhas e de ovos com dois produtos à base de capsaicina, capsainóides e alil isotiocianato. Uma mistura peneirada de solo e areia na proporção 1:1 (v:v) foi colocada em vasos de plástico e infestada com 4000 ovos de M. javanica. Quatro dias após 20 mL de cada extrato, na concentração de 1000 ppm, foram espalhados sobre o solo. Apenas água foi derramada sobre o solo infestado no tratamento testemunha. Mudas de tomate com 20 dias de idade foram transplantadas quatro dias após a colocação dos extratos ao solo. Após quarenta e cinco dias avaliou-se o número de ovos e o número de galhas do sistema radicular de cada planta. Os extratos clorofórmico e cetônico de pimenta malagueta e o óleo de mostarda apresentaram melhor controle do nematóide, diferindo estatisticamente da testemunha quanto ao número de galhas. Porém, somente o óleo de mostarda reduziu significativamente o número de ovos quando comparado com a testemunha. Os extratos cetônico e clorofórmico de pimenta e o óleo de mostarda reduziram em 34,5%, 40,4% e 99,9% o número de galhas, respectivamente e o óleo de mostarda reduziu em 99,9% o número de ovos. No experimento seguinte foram avaliados o extrato clorofórmico de pimenta, o óleo de mostarda, o produto comercial Champon® e um produto em desenvolvimento na UFV, chamado DS, a base de capsaicina, capsainóides e alil isotiocianato em diferentes concentrações. Os produtos Champon® e DS e o óleo de mostarda reduziram o número de ovos e galhas quando comparados à testemunha em todas as concentrações testadas. O extrato de pimenta apresentou o melhor resultado na concentração de 400 ppm, reduzindo o número de ovos e galhas em relação à testemunha, porém esse foi bem maior quando comparado com os demais produtos testados.

Allelochemicals from the leaves of Tamarindus indica L.

Potent biopesticides with strong antimicrobial activity as well growth inhibitory activity has been isolated and purified from the Ethyl Acetate Fraction (TrEAF) of tamarind leaves. Chromatographic analyses (TLC, UV, MS, NMR, and IR) indicated the presence of putative caffeic acid derivative in Tamarind leaves. Aspergillus tamarii was highly sensitive to TrEAF compound at all concentrations (500 ppm, 1000 ppm, 1500 ppm and 2000 ppm) than Aspergillus fumigatus, Aspergillius niger. In Aspergillus tamarii and Aspergillius niger, 1500ppm concentration was very much sensitive to TrEAF compound. Cercina lutia, Staphylococcus aureus, Micrococcus roseus and Pseudomonas sp were much more sensitive to TrEAF compound than Escherichia coli. No effect of TrEAF compound was detected in E.coli at concentration of 1000ppm. When isolated and purified by fractionation and column chromatography, this active TrEAF compound showed concentration-dependent inhibitory/stimulatory activity on rice seeds. At concentration of 1000ppm, it showed 53.81% inhibition on shoot length and 58.85% inhibition in root length. At 500ppm concentration, 29.01% inhibition in shoot length and 38.82% inhibition in root length have been detected. Very slight stimulation on shoot length was observed at 7.81ppm. It showed no effect on the germination of rice seed.

Action of the chemical agent fipronil on the reproductive process of semi-engorged females of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae). Ultrastructural evaluation of ovary cells

The ovary of the tick Rhipicephalus sanguineus consists of a wall of epithelial cells and a large number of oocytes in five different developmental stages (I–V), which are attached to the wall by a pedicel. The present study provides ultrastructural information on the effects (dose–response) of the acaricide fipronil (Frontline®) on ovaries of semi-engorged females of R. sanguineus, as well as it demonstrates some possible defense mechanisms used by oocytes to protect themselves against this chemical agent. Individuals were divided into four groups. Group I was used as control while groups II, III and IV were treated with fipronil at the concentrations of 1, 5 and 10ppm, respectively. Fipronil at the concentration of 10ppm had the strongest effect on the development of oocytes. At this concentration, even oocytes that reached the final developmental stage exhibited damaged cell structures. Moreover, the observation in fipronil-treated R. sanguineus ticks of damaged cellular components such as plasmic membrane, mitochondria and protein granules (due to alteration in the protein synthesis), and cellular defense mechanisms such as increase in the amount of cytoplasmic microtubules and large amounts of digestive vacuoles and myelin figures, were only possible by means of ultrastructure.

Evaluation of subchronic toxicity of dietary administered Cry1Ab protein from Bacillus thuringiensis var. Kurustaki HD-1 in F344 male rats with chemically induced gastrointestinal impairment

Bacillus thuringiensis (Bt) proteins are developed for genetically modified crops and the Bt proteins demonstrate no evidence of toxicity by the oral route in traditional animal models. However, the possible toxicity of Bt proteins under conditions of reduced gastric acid secretion and/or small intestinal damage has not been investigated. In the present study, we therefore evaluated following four F344 rat groups with a purified Bt protein Cry1Ab from B. thuringiensis var. Kurustaki HD-1. Gastrointestinal impairment (GI) alone and GI+Bt protein fed (GI+Bt) groups were given i.p. injections of famotidine to reduce gastric acid secretion twice a day at 30mg/kg body weight in weeks 2 and 4. GI and GI+Bt groups were additionally fed diets containing 80ppm indomethacin for induction of intestinal damage during weeks 1 and 3. Bt alone and GI+Bt groups were also fed diet containing Bt protein Cry1Ab at a concentration of 10ppm in weeks 2 and 4. A no treatment control group was also included. At the end of week 4, all animals were euthanized under ether anesthesia, blood samples were collected for hematology and serum biochemistry and a complete necropsy was performed. No significant changes indicative of toxicity of the Bt protein Cry1Ab used here were noted with any of the parameters investigated. In conclusion, no significant toxicological effects were detected in this subchronic gastrointestinal impairment rat model.

In vitro study on thiabendazole action on viability of Ascaris lumbricoides (Lineu, 1758) eggs.

The in vitro activity of thiabendazole on Ascaris lumbricoides eggs, which were recovered from uteri of worm excreted after chemotherapeutic treatment, was studied. Four concentrations of the drug were used: 1 - 2.5 - 5 - and 10 ppm during 24, 48 and 72 hours of exposure. Subsequently, the eggs were centrifuged, washed three times and H(2)SO(4)0.1N was added. The eggs were maintained in an incubator for 20 days at 28 degrees C. Finally, the percentage of embryonated eggs was determined under a lightmicroscope at a 100X magnification. After 48 and 72 hours of thiabendazole exposure, at a concentration of 10ppm, the drug showed complete inhibition of egg embryonation.

Study of the effect of some different growth regulators and light and dark factors on the percentage of germination of local lettuce seeds (Lactuca Sativa)

This study aimed at the effect of different concentrations of the growth regulators gibberellin acid GA3 and indole acetic acid IAA each with three concentrations in addition to the comparison treatment with the effect of light and dark factors on the germination rate of lettuce seeds of the local variety, where GA3 led to a significant increase compared to the control treatment, especially At a concentration of 1000ppm in the dark, while IAA led to an increase in the percentage of germination, but in a non-significant manner, as for the factors of light and darkness, the percentage of germination increased significantly in the dark compared to the light treatment.

Microbial transformation of polychlorinated phenoxy phenols.

Microbial metabolism of polychlorinated phenoxy phenols (PCPPs) and polychlorinated phenoxy anisoles (PCPAs) was studied in mixed and pure bacterial cultures and in PCPP-contaminated soil. Both in the laboratory and in the field the PCPPs with a hydroxyl group in the para position in the molecule were methylated faster than those with a hydroxyl group in the ortho position. Rhodococcus chlorophenolicus, a polychlorophenol mineralizer, methylated 40% of one PCPP compound in 7 days, given in a concentration of 10ppm. The methylation was aerobic. There was no further metabolism of PCPAs. One of the PCPA-compounds was also o- demethylated by R. chlorophenolicus. In chlorophenol-contaminated soil each of the 8 PCPPs contained in a technical chlorophenol product became methylated.

Stabilization of β-D-galactosidase from heat and chemical inactivation with the extract ofPanax ginseng C.A. Meyer

Staiblization effect ofPanax ginseng C. A. Meyer on β-D-galactosidase inactivation was pro ved by kinetic studies of thermal inactivation of the enzyme. The water extractPanax ginseng C.A. Meyer showed stabilization activity at minimal concentration of 10ppm. The methanolic extract was purified to obtain ginseng saponins, and two groups of the ginsenosides,i.e., protopanaxadiol and protopanaxatriol were isolated. They also showed a protective effect against the thermal and chemical inactivation of the enzyme;p-chloromercuribenzoic acid and hydroxylamine known as protein modifier greatly inactivated the enzyme but inactivation was significantly blocked by the ginseng component. Mg2+. known as a cofactor, stabilized the enzyme and the poor stabilization effect by it was potentiated by ginseng components.

Determination of lethal concentration and antibacterial activity of commonly used disinfectants

The toxic effects of four disinfectants viz., copper sulfate (CuSO4), potassium permanganate (KMnO4), methylene blue and malachite green on fish and fish pathogenic bacteria Aeromonas sp., Pseudomonas fluorescens, Edwardsiella sp. and Flavobacterium sp. were investigated. Lethal concentration of the disinfectants to fingerlings of Labeo rohita was determined in aquarium by standard method. Lethal concentration of copper sulfate (CuSO4), potassium permanganate (KMnO4), methylene blue and malachite green against fish were found in 0.75ppm, 7ppm, 6ppm and 0.5ppm at 21.4hrs, 18hrs, 9.5hrs and 1.40hrs, respectively. Methylene blue at 4ppm and 5ppm concentration inhibited the growth of Pseudomonas fluorescens and 6ppm concentration suppressed the growth of Aeromonas sp. Copper sulfate (CuSO4) was effective only against Edwardsiella sp at concentration of 10ppm and 8ppm. Malachite green repressed the growth of all four tasted bacteria at a concentration of 1ppm. Potassium permanganate (KMnO4) was failed to exhibit any inhibitory effect on the bacteria even at 30ppm concentration. DOI: http://dx.doi.org/10.3329/ijns.v1i4.9738 IJNS 2011 1(4): 102-105

Antibiotics as protectant bactericide against bacterial leaf blight of rice plant

1. Since the antibacterial effect of cellocidin on X. oryzae was antagonized by cysteine and glutathione, cellocidin was considered to interact with -SH groups.2. The oxidation of various intermediates of the Krebs' cycle by the cell-free extracts of X. oryzae, prepared by sonic oscillator, and also the effect of cellocidin on the oxidation, were studied by measuring the reduction of triphenyl tetrazolium chloride. It was found that cellocidin at the minimum growth-inhibitory concentration (10ppm) inhibited selectively NAD requiring dehydrogenases, such as α-ketoglutarate dehydrogenase, glutamic dehydrogenase, and malic dehydrogenase, but did not inhibit NAD non-requiring dehydrogenases, such as succinic dehydrogenase and urease.3. Effect of cellocidin on oxygen uptake by cell-free extracts of X. oryzae prepared by sonic oscillator, was studied in the presence of related metabolic intermediate of the Krebs' cycle as substrates. It was found that the oxygen uptake was inhibited by cellocidin at a concentration of 100mcg/ml when substrates such as α-ketoglutarate, iso-citrate etc. which require NAD as co-enzyme for oxidation, were used, but was not inhibited when succinate was used as substrate.4. Effect of cellocidin on the system α-ketoglutarate→succinate, of X. oryzae, was studied. When the oxidation of succinate was inhibited by the addition of malonate, the oxidation of α-ketoglutarate, in the presence of NAD, by cell-free extracts of X. oryzae, was inhibited by cellocidin at a concentration of 1mcg/ml, which is smaller than the minimum growth-inhibitory concentration. Therefore cellocidin was considered to be an inhibitor on the system α-ketoglutarate→succinate.5. Cellocidin, at a concentration of 100ppm, did not inhibit electron transport system, such as NADH2 oxidase and NAD reductase, of cell-free preparations of X. oryzae.6. The incorporation of 14C-amino acids into the protein fraction of X. oryzae was not inhibited by cellocidin at a concentration of 10ppm.

The sporulation-inhibitive effects of sulfadiazine on wheat leaf rust

The effects of sulfadiazine on the infection of wheat seedlings by leaf rust, Puccinia triticina, were examined.The development of uredosori on seedlings of the highly susceptible wheat varieties is remarkably inhibited by soil application of sulfadiazine-Na salt aq. at the rate of 40mg per 100sq. cm within 2 days after inoculation. With delay in application of the sulfadrug, rust-inhibitive effect decreased rapidly. Phytotoxic secondary effects, i. e. stunting of the plants and chlorosis of the leaves, were fairy marked at the effectual dosage. The effect of application before inoculation is well maintained for at least 9 days.When wheat seedlings are sprayed to “run off” with the preparation up to a concentration of 1000ppm plus 1 per cent Tween-20 as a wetting agent, the development of sori is inhibited for some periods, but later on resumed gradually, the effect is very poor compared with that of soil application.The rust-inhibitive effects of sulfadiazine are conteracted by the supply of p-amino benzoic acid.