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High Resistance (high + resistance)
Kinds of High Resistance Selected AbstractsHigh resistance to aerial oxidation of an amorphous NiB/SiO2 catalyst: TP-XRD, TPR and related investigationsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2004Yong-Zhen Wang Abstract An amorphous NiB/SiO2 catalyst, prepared by a reductive,impregnation method, was thoroughly studied as to its behavior in air and in benzene hydrogenation in a fixed-bed reactor at atmospheric pressure. The results showed that the amorphous NiB/SiO2 catalyst possessed long life and excellent resistance to aerial oxidation. Even after calcination at 400 °C, TP-XRD and TPR measurements revealed that the amorphous NiB/SiO2 catalyst was not oxidized, and could retain its activity in benzene hydrogenation. Copyright © 2004 Society of Chemical Industry [source] Solid Contact Micropipette Ion Selective Electrode II: Potassium Electrode for SECM and In Vivo ApplicationsELECTROANALYSIS, Issue 17-18 2009Gergely Gyetvai Abstract Micropipette ion selective electrodes are very small, but fragile, short-life time sensors with very high resistance. Their high resistance is a draw back considering application in scanning electrochemical microscopy (SECM) and in life sciences. New, low resistance potassium micropipette electrodes were prepared, and applied. The electrode contains solid internal contact made of a carbon fiber lowered down all the way close to the orifice of the micropipette. The internal contact potential was kept constant by applying a doped, electrochemically prepared PEDOT coating on the fiber surface. The electrode performed well in in vivo experiments both in plant and animal tissue without capacitance neutralization and in SECM. [source] E6* oncoprotein expression of human papillomavirus type-16 determines different ultraviolet sensitivity related to glutathione and glutathione peroxidase antioxidant defenceEXPERIMENTAL DERMATOLOGY, Issue 6 2005Stéphane Mouret Abstract:, Clinical observations of non-melanoma skin cancer in immunocompromised patients, such as organ transplant recipients, suggest co-operative effects of human papillomavirus (HPV) and ultraviolet (UV) radiation. The aim of the present study is to evaluate UV sensitivity and DNA damage formation according to antioxidant status in HPV16-infected keratinocytes. We used SKv cell lines, infected with HPV16 and well characterized for their proliferative and tumorigenic capacities. We showed that SKv cell lines presented various E6* (a truncated form of E6) RNA levels. We demonstrated that the higher oncoprotein RNA expression level was associated with a higher resistance to solar-simulated radiation, more specifically to UVB radiation and to hydrogen peroxide. Moreover, this high resistance was associated with a low oxidative DNA damage formation after UV radiation and was related to high glutathione content and glutathione peroxidase activities. Therefore, the results of our study suggest that E6* levels could modulate the glutathione/glutathione peroxidase pathway providing a mechanism to protect HPV-infected keratinocytes against an environmental oxidative stress, such as UV radiation. [source] Genetic variability of the ,bark canker resistance' character in several natural provenances of Cupressus sempervirensFOREST PATHOLOGY, Issue 2 2000A. Santini Summary Several Aegean (Greece) and Anatolian (Turkey) cypress provenances were studied for resistance variability to bark canker, a disease caused by the fungal pathogen Seiridium cardinale. The investigation also examined whether the low disease rate within the natural area of cypress was due to genetic or geographic-climatic reasons. Results demonstrated strong variability for the ,bark canker resistance' character, in particular for trees within families. As trees from the provenances studied were not found to have genetic superiority for bark canker resistance, the above-mentioned low disease rate could be due to geographic-climatic barriers that inhibit the development of the fungus or its ability to infect the host. Several half-sib progenies exhibited high resistance, suggesting that this character is totally inherited through the maternal line. Should this finding be confirmed by further research, it would facilitate the task of genetic improvement for resistance, allowing progenies of resistant trees to be obtained. [source] Amphiregulin is a factor for resistance of glioma cells to cannabinoid-induced apoptosisGLIA, Issue 13 2009Mar Lorente Abstract Gliomas, one of the most malignant forms of cancer, exhibit high resistance to conventional therapies. Identification of the molecular mechanisms responsible for this resistance is therefore of great interest to improve the efficacy of the treatments against these tumors. ,9-Tetrahydrocannabinol (THC), the major active ingredient of marijuana, and other cannabinoids inhibit tumor growth in animal models of cancer, including glioma, an effect that relies, at least in part, on the ability of these compounds to induce apoptosis of tumor cells. By analyzing the gene expression profile of two sub-clones of C6 glioma cells with different sensitivity to cannabinoid-induced apoptosis, we found a subset of genes with a marked differential expression in the two sub-clones. Furthermore, we identified the epidermal growth factor receptor ligand amphiregulin as a candidate factor to mediate the resistance of glioma cells to cannabinoid treatment. Amphiregulin was highly overexpressed in the cannabinoid-resistant cell line, both in culture and in tumor xenografts. Moreover, in vivo silencing of amphiregulin rendered the resistant tumors xenografts sensitive to cannabinoid antitumoral action. Amphiregulin expression was associated with increased extracellular signal-regulated kinase (ERK) activation, which mediated the resistance to THC by blunting the expression of p8 and TRB3,two genes involved in cannabinoid-induced apoptosis of glioma cells. Our findings therefore identify Amphirregulin as a factor for resistance of glioma cells to THC-induced apoptosis and contribute to unraveling the molecular bases underlying the emerging notion that targeted inhibition of the EGFR pathway can improve the efficacy of antitumoral therapies. © 2009 Wiley-Liss, Inc. [source] A New Poly(thienylenevinylene) Derivative with High Mobility and Oxidative Stability for Organic Thin-Film Transistors and Solar CellsADVANCED MATERIALS, Issue 27 2009Bogyu Lim A novel thiophene-thienylenevinylene copolymer is synthesized and evaluated for use in organic field-effect transistors and organic solar cells. PETV12T shows good solution processability and high structural organization after annealing. Organic thin-film transistors based on the polymer exhibit high mobility and a high resistance to oxidation. In addition, PETV12T shows potential as an electron donor in bulk heterojunction solar cells. [source] Antimicrobial activity of varying concentrations of sodium hypochlorite on the endodontic microorganisms Actinomyces israelii, A. naeslundii, Candida albicans and Enterococcus faecalisINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2004C. E. Radcliffe Abstract Aim, To determine the resistance of microorganisms associated with refractory endodontic infections to sodium hypochlorite used as a root canal irrigant. Methodology, Two strains each of Actinomyces naeslundii, Candida albicans and Enterococcus faecalis were tested as late logarithmic phase inocula, against sodium hypochlorite adjusted to 0.5, 1.0, 2.5 and 5.25% w/v. Contact times used were 0, 10, 20, 30, 60 and 120 s. In the case of E. faecalis, additional experiments used contact times of 1.0, 2.0, 5.0, 10.0 and 30.0 min. Anti-microbial action was halted by sodium thiosulphate addition. Survivors were measured primarily using viable counts on drop plates. Additionally, pour plates were used to count low colony-forming units (cfu) and dilutions to 10,6 were used to count high cfu. Results, All concentrations of NaOCl lowered cfu below the limit of detection after 10 s in the case of A. naeslundii and C. albicans. However, E. faecalis proved to be more resistant to NaOCl. Using 0.5% NaOCl for 30 min reduced cfu to zero for both strains tested. This compares with 10 min for 1.0%, 5 min for 2.5% and 2 min for 5.25% (P < 0.001). Regression analysis for the dependent variable loge(count + 1) with loge(time + 1) and concentration as explanatory variables gave rise to a significant interaction between time and concentration (P < 0.001). Conclusion, The published association of E. faecalis with refractory endodontic infection may result, at least partially, from high resistance of this species to NaOCl. This does not appear to be the case with A. naeslundii or C. albicans. [source] Flows through horizontal channels of porous materialsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2003A.K. Al-Hadhrami Abstract In this paper, the control volume method (CVM) with the staggered grid system is utilized to solve the two-dimensional Brinkman equation for different configurations of porous media in a horizontal channel. The values of the permeability of sand and clear fluid are considered when performing several numerical investigations which enable the evaluation of the behaviour of the flow through regions that mathematically model some geological features (faults/fractures) present in oil reservoirs or groundwater flows. We have found that the convergence of the CVM can be achieved within a reasonable number of iterations when there is a gap present between a partial barrier of low Darcy number and the channel boundary. However, a complete barrier across the channel results in a very high resistance and hence there is a large pressure drop which causes difficulties in convergence. In order to improve the rate of convergence in such situations, an average pressure correction (APC) technique, which is based on global mass conservation, is developed. The use of this technique, along with the CVM, can rapidly build up the pressure drop across such a barrier and hence dramatically improve the rate of convergence of the iterative scheme. Copyright © 2003 John Wiley & Sons, Ltd. [source] Lifetime prediction of CAD/CAM dental ceramics,JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 6 2002Ulrich Lohbauer Abstract The dynamic fatigue method was used to obtain subcritical crack growth parameters n and A for a commercial feldspathic dental porcelain and for a lanthanum-glass-infiltrated alumina glass ceramic. Five stress rates d,/dt ranging from 50 to 0.01 MPa s,1 were applied. The inert strength values were calculated with the use of Weibull statistics and maximum-likelihood approaches for the Weibull parameter m. Strength,probability,time (SPT) diagrams were derived for both materials. The alumina glass composite showed a high fracture strength ,0 (442 MPa) at a failure probability of PF = 63.2% and a high resistance against subcritical crack growth (n = 36.5). The development of strength under fatigue conditions was calculated for exemplary 1 year. The strength of the alumina glass material dropped to 228 MPa within this period. This fact is due to a low content of infiltrated lanthanum glass phase in the composite material (25 wt%). In contrast, for the high-silica-glass-containing porcelain a distinct decrease of strength ,0 from initial 133 to 47 MPa after 1 year was predicted. This, mainly because of a low crack growth resistance (n = 16.8) of the feldspathic porcelain. Much lower strength values were calculated, assuming a failure probability of PF = 5%. The decrease is mainly caused by the sensitivity of high,glass-containing ceramics against water corrosion. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 780,785, 2002 [source] Simultaneous purification and immobilization of bitter gourd (Momordica charantia) peroxidases on bioaffinity supportJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2005Suhail Akhtar Abstract This paper demonstrates the construction of an inexpensive bioaffinity adsorbent by simply incubating Sephadex G 50 matrix with jack bean meal extract at room temperature. Sephadex G 50 adsorbed 17 mg Con A (concanavalin A) per g of the matrix. Con A-adsorbed Sephadex was employed for the immobilization of glycoenzymes directly from ammonium sulfate-fractionated proteins of bitter gourd. The obtained bioaffinity support was very efficient for high yield immobilization of peroxidases from bitter gourd and it bound nearly 425 enzyme units per g of the matrix. Bitter gourd peroxidase immobilized on lectin,Sephadex support showed a very high effectiveness factor, ,,,' of 1.25. Immobilized BGP preparation was quite stable against the denaturation induced by pH, heat, urea, Triton X 100, Tween 20, SDS, Surf Excel and water-miscible organic solvents: dimethyl sulfoxide and dimethyl formamide. Low concentration of detergents like SDS, Tween 20, and Triton X 100 enhanced the activity of soluble and immobilized bitter gourd peroxidase. Peroxidase bound to the bioaffinity support exhibited very high resistance to proteolysis caused by the trypsin treatment. Con A,Sephadex-bound bitter gourd peroxidase retained 85% of its initial activity after treatment with 2.5 mg trypsin per cm3 of incubation mixture for 1 h at 37 °C while the soluble enzyme lost nearly 40% of the initial activity under similar incubation conditions. Immobilized bitter gourd peroxidase preparation appeared to be more rigid to proteolysis mediated by trypsin compared with soluble bitter gourd peroxidase. Copyright © 2004 Society of Chemical Industry [source] WATER ACTIVITY AND THE INACTIVATION OF ENTEROBACTER CLOACAE INOCULATED IN CHOCOLATE LIQUOR AND A MODEL SYSTEM BY PULSED ELECTRIC FIELD TREATMENTJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2002S. MI Effects of water activity (aw) on the inactivation of Enterobacter cloacae inoculated in chocolate liquor and in a model system of 0.1% (w/v) peptone water and glycerol by pulsed electric field (PEF) treatment were investigated. An electric field strength of 24.5 kV/cm, a total treatment time of 320 ,s, a pulse duration time of 4 ,s, a pulse delay time of 15 ,s, and a pulse cycle time of 15 s were selected for PEF treatment. The inactivation ofE. cloacae by PEF increased significantly as aw increased (P < 0. 05). As aw of chocolate liquor increased from 0.48 to 0.89, the log reduction of E. cloacae increased from 0.1 to 1.3. The measured temperature change inside the PEF treatment chamber was 0.4C when the log reduction was 1. 3. Similarly, as aw increased from 0. 51 to 0.91 in the model system, the log reduction increased from 0.4 to 1.3. E. cloacae surviving a low aw environment had high resistance to PEF. PEF inactivated E. cloacae in the chocolate liquor with aw of 0.85 by 1 log at O h incubation. However, the log reduction was only 0.1 when PEF treatment was applied to E. cloacae which was incubated for 2 h in the chocolate liquor with aw of 0.85 before PEF treatment. E. cloacae surviving the low aw environment might have resistance not only to the low aw but also to PEF. The resistance to low aw environment may need to be considered when the inactivation of microorganisms by PEF is evaluated. [source] Nanometer-scale surface modification by polymerization of tetrafluoroethylene on polymer substrates in supercritical fluoroformJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2008Toshiaki Mori Abstract Surface penetrated polymerization of tetrafluoroethylene (TFE) was carried out on a polycarbonate (PC) plate in supercritical fluoroform (scCHF3). Since the high diffusiveness is one of peculiar features of supercritical fluids, TFE monomers and initiators (perfluorinated benzoyl peroxide) could penetrate into the surface of polymer substrates and be photo-polymerized. After washing physisorbed homopolymers on the surface, polytetrafluoroethylene (PTFE) was found to penetrate into 50,800 nm depth from the surface and covered the PC surface in the proportion of 85%. The surface coverage density and the penetration depth could be controlled by adjusting of the pressure of scCHF3. The TFE-penetrated polymerization could be applied for various polymer plates such as polyethylene, polystyrene, polypropylene, poly(ethylene terephthalate), and polyimide. In addition to polymer plates, this technique could be applied to a cellulose paper, a nylon textile, and a porous PC membrane. The PTFE-penetrated nylon textile showed a high resistance for washing test with detergents, compared with the commercial fluoropolymer-sprayed nylon textile. The PTFE-penetrated porous PC membrane showed high oxygen permeability (P/P = 5.2), compared with that of the untreated PC membrane (P/P = 3.5) in gas permeation experiments of O2 and N2. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1577,1585, 2008 [source] Characterization of the active site structure of Pd and Pd-promoted Mo sulfide catalysts by means of XAFSJOURNAL OF SYNCHROTRON RADIATION, Issue 2 2001Takeshi Kubota Recently, noble metal catalysts are noted as promising candidates for new super-deep-hydrodesulfurization (HDS) catalysts. In this study, we investigated the structure of Pd particles supported on zeolite and Al2O3 under a sulfidation or reduction condition. From EXAFS analysis, it was found for sulfided Pd catalysts that small Pd sulfide clusters are formed without sintering. It was also revealed that no extensive growth of metal Pd particles occurs in Pd/NaY sulfide catalysts even after a treatment with H2 at 673 K. The dispersion of Pd metal particles is improved by H2/H2S treatment. These results indicate that in the presence of H2S, Pd shows high resistance against particle growth. A comparison of the Mo and Pd K-edge EXAFS spectra for MoSx/Pd-NaY and Pd-NaY catalysts revealed the existence of Mo-Pd bondings by the addition of Mo sulfide, indicating a direct interaction between Mo and Pd sulfides. [source] Vitamin C Requirements of the Angelfish Pterophylum scalareJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2000Jozef H. Blom Ascorbic acid requirements of fishes of the cichlid family appear to vary widely. Juvenile angelfish, a widely produced ornamental cichlid, were maintained on diets containing graded levels of ascorbyl monophosphate. Liver ascorbic acid concentrations after 96 d of feeding were significantly reduced in groups receiving 120 mg or less ascorbic acid equivalents/kg diet. However, no differences in growth or mortality between groups were found, and no external signs of ascorbic acid deficiency were observed, indicating a high resistance of this species against prolonged ascorbic acid deficiency. Based on the long possible life span of angelfish in the aquarium, we proposed a conservative dietary ascorbic acid requirement of 360 mg/ kg diet, necessary to maintain maximum tissue storage of this vitamin. [source] A classification of the fibrin network structures formed from the hereditary dysfibrinogensJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2006T. SUGO Summary.,Objective: The main objective was to study the relationships of the molecular defects in 38 dysfibrinogens with their fibrin networks. Methods and results: Scanning electron microscopic analyses revealed that all the fibrins formed under the same conditions had networks composed of either normal thickness fibers or thin fibers, accompanied by a variety of alterations in the network structure and characteristics. We classified these fibrin networks into five classes, designated normal, less-ordered, porous A, porous B and lace-like networks. The dysfibrinogens with defects in fibrinopeptide A release or the E:D binding sites formed normal or less-ordered networks, while those with defects in the D:D association formed porous A networks composed of many tapered terminating fibers, despite having fibers of normal width, and containing many pores or spaces. The porous B and lace-like networks were composed of highly branched thin fibers because of defects in the lateral association among protofibrils, and the major difference between them was the porosity of the porous B networks. All the porous B networks were easily damaged by mechanical stress, whereas the lace-like networks retained high resistance to such stress, indicating that the network strength was not dependent on the fiber width, but on the porosity that led to fragility of the network. Conclusion: Impairment of the D:D association is the major disturbing factor that leads to the formation of porous fibrin networks. The porosity may be introduced by severe impairment of the D:D association, as well as the lateral association, as has often been observed by extra glycosylation or defects in Ca2+ binding. [source] Hydroxylated Linear Polyurethanes Derived from Sugar AlditolsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 6 2009Romina Marín Abstract A set of linear [m,n]-type polyurethanes was synthesized by reaction of HDI or MDI with conveniently protected sugar alditols L -threitol (LTh), L -arabinitol (LAr) and xylitol (Xy). of the resulting polyurethanes ranged between 10,000 and 60,000 with polydispersities around 2. They were thermally stable, showing no decomposition up to temperatures near 300,°C. They all were amorphous polymers with Tg highly dependent on the constitution of the diisocyanate, but scarcely dependent on the structure of the alditol. Hydrogenation of the LThBn-HDI polyurethane yielded partially debenzylated products with Tg values ranging between 20 and 30,°C. Fully benzylated polyurethanes showed high resistance to hydrolytic degradation, whereas polyurethane with free hydroxyl side groups degraded significantly in saline buffer at pH,=,10 and 37,°C. [source] Corrosion behavior of Ti-xNb-13Zr alloys in Ringer's solutionMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 12 2008A. Robin Abstract Ti-6Al-4V alloy has been widely used in restorative surgery due to its high corrosion resistance and biocompatibility. Nevertheless, some studies showed that V and Al release in the organism might induce cytotoxic effects and neurological disorders, which led to the development of V-free alloys and both V- and Al-free alloys containing Nb, Zr, Ta, or Mo. Among these alloys, Ti-13Nb-13Zr alloy is promising due to its better biomechanical compatibility than Ti-6Al-4V. In this work, the corrosion behavior of Ti, Ti-6Al-4V, and Ti-xNb-13Zr alloys (x,=,5, 13, and 20) was evaluated in Ringer's solution (pH 7.5) at 37,°C through open-circuit potential measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy. Spontaneous passivity was observed for all materials in this medium. Low corrosion current densities (in the order of 10,7 A/cm2) and high impedance values (in the order of 105 ,cm2 at low frequencies) indicated their high corrosion resistance. EIS results showed that the passivating films were constituted of an outer porous layer (very low resistance) and an inner compact layer (high resistance), the latter providing the corrosion resistance of the materials. There was evidence that the Ti-xNb-13Zr alloys were more corrosion resistant than both Ti and Ti-6Al-4V in Ringer's solution. [source] Fusion protein consisting of the first immunoglobulin-like domain of porcine nectin-1 and Fc portion of human IgG1 provides a marked resistance against pseudorabies virus infection to transgenic miceMICROBIOLOGY AND IMMUNOLOGY, Issue 1 2009Yukiko Tomioka ABSTRACT Nectin-1 is a Ca2+ -independent Ig-like cell,cell adhesion molecule and an alphaherpesvirus receptor that binds to virion glycoprotein D by the first Ig-like domain. We have investigated the antiviral potentials of soluble forms of porcine nectin-1 to PRV infection by generating transgenic mice expressing different types of fusion protein. Previously, we reported that mice transgenic for a chimera that carried the entire ectodomain of porcine nectin-1 fused to the Fc portion of porcine IgG1 were more resistant than those transgenic for a chimera that carried the first Ig-like domain fused to the Fc portion. Recently, we generated transgenic mice expressing a fusion protein made of the first Ig-like domain fused to the Fc portion of human IgG1, and reported that they showed a microphthalmia. Here, two transgenic mouse lines expressing the fusion protein were challenged with PRV for comparing their resistances with those of transgenic mice expressing different types of fusion protein. Surprisingly, both transgenic mouse lines showed a high resistance to the viral infection, especially via the i.n. route. Significant resistance of the embryonic fibroblasts was also observed. Altogether, these findings indicated that the fusion protein consisting of the first Ig-like domain fused to the human Fc portion provided a marked resistance against PRV infection to the transgenic mice. [source] Novel method for testing the grease resistance of pet food packagingPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2002J. Lange Abstract For paper-based dry pet food packaging, one of the main requirements is a high resistance against staining from the fat in the product. For both development and quality control, rapid and reliable standardized test procedures assessing this property are needed. Although a number of tests are available, they either apply only to certain types of packaging materials and show limited correlation with field behaviour, or employ non-standard testing substances, long testing times and complicated equipment. In response to this situation, a new testing procedure that reflects field behaviour but without the drawbacks of the existing tests has been developed. The new test shows high reproducibility and good correlation with field performance for a wide range of multiwall bag and folding box materials with different types of grease resistance treatment. Copyright © 2002 John Wiley & Sons, Ltd. [source] Fipronil resistance in the whitebacked planthopper (Sogatella furcifera): possible resistance mechanisms and cross-resistancePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2010Jian Tang Abstract BACKGROUND: The whitebacked planthopper (WBPH), Sogatella furcifera (Horváth), is a major rice pest in many parts of Asia. Fipronil has been widely used to control rice pests, and resistance to fipronil has been reported in some important species. RESULTS: A field population (F) of WBPH was collected, with 50.5-fold resistance to fipronil, which increased to 137.5-fold (F-se) after continuous selection for 11 generations. The F-se population did not show significant cross-resistance to the insecticides examined by comparison with the F population. TPP (synergism ratio 1.9), DEM (1.5) and PBO (1.1) showed only slight synergism on fipronil in the F-se population. A large increase was found in esterase and P450 monooxygenase activity in the F-se population. In vitro, PBO inhibited both esterase and P450 monooxygenase activity, and TPP inhibited esterase activity in the F-se population. CONCLUSION: Synergistic study in vivo and biochemical study in vitro indicated that esterase and P450 monooxygenases might be important factors for fipronil resistance in the selected population F-se. However, these biochemical factors could not lead to such high resistance (137.5-fold) in the F-se population, and target-site insensitivity would be another or more important factor. Copyright © 2009 Society of Chemical Industry [source] Development of insect-resistant transgenic rice with Cry1C*-free endospermPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 9 2009Rongjian Ye Abstract BACKGROUND: Yellow stem borer (Tryporyza incertulas Walker), striped stem borer (Chilo suppressalis Walker) and leaf folder (Cnaphalocrocis medinalis Guenec) are three lepidopteran pests that cause severe damage to rice in many areas of the world. In this study, novel insect-resistant transgenic rice was developed in which Bt protein expression was nearly absent in the endosperm. The resistant gene, cry1C*, driven by the rice rbcS promoter (small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase), was introduced into Zhonghua 11 (Oryza sativa L. ssp. japonica) by Agrobacterium -mediated transformation. RESULTS: A total of 83 independent transformants were obtained, 19 of which were characterised as single-copy foreign gene insertion. After preliminary screening of the T1 families of these 19 transformants in the field, six highly insect-resistant homozygous lines were selected. These six homozygous transgenic lines were field tested for resistance to leaf folders and stem borers, and for their agronomic performance. The Cry1C* protein levels in leaves and endosperm were measured by ELISA. Subsequently, the elite transgenic line RJ5 was selected; this line not only possessed high resistance to leaf folders and stem borers, normal agronomic performance, but also Cry1C* expression was only 2.6 ng g,1 in the endosperm. CONCLUSION: These results indicated that RJ5 has the potential for widespread utility in rice production. Copyright © 2009 Society of Chemical Industry [source] Lack of cross-resistance to indoxacarb in insecticide-resistant Spodoptera frugiperda (Lepidoptera: Noctuidae) and Plutella xylostella (Lepidoptera: Yponomeutidae)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 1 2007Simon J Yu Abstract Two field strains of the fall armyworm, Spodoptera frugiperda (JE Smith), collected from corn in north Florida showed high resistance to carbaryl (626- and 1159-fold) and moderate resistance to parathion-methyl (30- and 39-fold) as compared with a laboratory susceptible strain. A field strain of the diamondback moth, Plutella xylostella (L.) collected from cabbage in north Florida and selected for 20 generations with permethrin showed high resistance to permethrin (987-fold) as compared with a susceptible strain. However, in all instances, no cross-resistance to indoxacarb, a novel oxidiazine insecticide, was observed in these two species. Biochemical studies revealed that, in S. frugiperda, activities of detoxification enzymes (microsomal oxidase, glutathione S -transferase and general esterase) were significantly higher in the field strains than in the susceptible strain, indicating that these detoxification enzymes were not actively involved in the resistance to indoxacarb. The lack of cross-resistance between indoxacarb and permethrin in P. xylostella further supports the notion that the mode of action of these insecticides on the insect sodium channel is different. Copyright © 2006 Society of Chemical Industry [source] Cotton whitefly (Bemisia tabaci) resistance to organophosphate and pyrethroid insecticides in PakistanPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2002Mushtaq Ahmad Abstract Resistance to three organophosphate and four pyrethroid insecticides was monitored from 1992 to 2000 in field populations of adult whiteflies, Bemisia tabaci, from Pakistan using a leaf-dip method. There was generally a very high resistance to dimethoate and deltamethrin, and a moderate resistance to monocrotophos during 1992 to 1996. From 1997 to 2000, resistance to these insecticides dropped to low levels because of less reliance on them for whitefly control, and introduction of new chemistries with novel modes of action that had no cross-resistance to conventional insecticides. Concurrently, whitefly resistance to acephate, fenpropathrin, lambda-cyhalothrin and bifenthrin mostly remained low. An insecticide resistance management strategy is recommended that particularly emphasizes the rotation of still-effective insecticides from different chemical classes along with the use of novel chemicals and other tactics of integrated pest management. © 2001 Society of Chemical Industry [source] Positron annihilation study of recrystallization behaviour in Zr2.5%Nb alloyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2009S. Mulki Abstract In CANDU reactors Zr 2.5%Nb alloy is used as pressure tube material due to low neutron absorption cross section, a high resistance to corrosion in water, high strength and good creep resistance. The two phase alloy consists of ,-fcc and ,-bcc. The recrystallization behavior of Zr2.5Nb strongly depends on morphology and distribution of second phase. In this study, the material was deformed to 60% and then was recrystallized in , + , region for different duration (i.e. 2 minutes to 14 days at 700 °C). The recrystallized microstructure was characterized by Orientation Imaging Microscopy (OIM). The evolution of microstructure was examined by Positron Lifetime Spectroscopy and Doppler Broadening measurement for each heat treated samples. Results from positron annihilation studies and other microstructural examination have been used to rationalize the recrystallization aspects, defects and ,-phase distribution. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Ecophysiology of Antarctic vascular plantsPHYSIOLOGIA PLANTARUM, Issue 4 2002Miren Alberdi Most of the ice and snow-free land in the Antarctic summer is found along the Antarctic Peninsula and adjacent islands and coastal areas of the continent. This is the area where most of the Antarctic vegetation is found. Mean air temperature tends to be above zero during the summer in parts of the Maritime Antarctic. The most commonly found photosynthetic organisms in the Maritime Antarctic and continental edge are lichens (around 380 species) and bryophytes (130 species). Only two vascular plants, Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth) Bartl., have been able to colonize some of the coastal areas. This low species diversity, compared with the Arctic, may be due to permanent low temperature and isolation from continental sources of propagules. The existence of these plants in such a permanent harsh environment makes them of particular interest for the study of adaptations to cold environments and mechanisms of cold resistance in plants. Among these adaptations are high freezing resistance, high resistance to light stress and high photosynthetic capacity at low temperature. In this paper, the ecophysiology of the two vascular plants is reviewed, including habitat characteristics, photosynthetic properties, cold resistance, and biochemical adaptations to cold. [source] Microsatellite marker for yellow rust resistance gene Yr5 in wheat introgressed from spelt wheatPLANT BREEDING, Issue 6 2002Q. Sun Abstract Yellow rust of wheat caused by Puccinia striiformis f sp. tritici has been periodically epidemic and severely damaged wheat production in China and throughout the world. Breeding for resistant cultivars has been proved to be an effective way to resolve the problem. A yellow rust resistance gene, Yr5, derived from Triticum spelta shows immunity or high resistance to the most popular isolates Tiaozhong 30 and 31 in China. Establishment of DNA markers for the Yr5 gene will facilitate marker-assisted selection and gene pyramiding in the breeding programme. Since the Yr5 gene was cytologically located on the long arm of chromosome 2B, By33, the donor of Yr5, was crossed and backcrossed with the susceptible line 441, and BC3F2 and BC3F3 segregating populations were screened for polymorphism by using 11 microsatellite primers mapped on chromosome 2B. A marker, Xgwm501-195 bp/160 bp, was found to be linked to Yr5, with a genetic distance of 10.5-13.3 cM. [source] Bacteriologic Comparison of Tonsil Core in Recurrent Tonsillitis and Tonsillar Hypertrophy,THE LARYNGOSCOPE, Issue 12 2007Jin Hyeok Jeong MD Abstract Objectives: Although many bacteriology studies on tonsillar diseases have been completed, all have been confined to children and were characterized by a paucity of cases. The purpose of this study was to analyze the underlying bacterial pathogens in tonsillar disease. Methods: A retrospective study was performed on 824 patients who underwent elective tonsillectomy with or without adenoidectomy. We analyzed the differences between the bacterial pathogens in recurrent tonsillitis and tonsillar hypertrophy with regard to age, season, and antibiotic sensitivity. Results: Among 824 cases, 966 bacterial strains from the tonsil core were isolated. In recurrent tonsillitis, Staphylococcus aureus was the most common pathogen (30.3%), followed by Haemophilus influenzae (15.5%) and group A ,-hemolytic Streptococcus (Streptococcus pyogenes, 14.4%). In patients over 14 years of age, quite differently from other age groups, Klebsiella pneumoniae was isolated at a significantly higher percentage. In tonsillar hypertrophy, H. influenzae was isolated most commonly (31.4%) regardless of age, followed by S. pyogenes (24.2%), S. aureus (22.9%), and Streptococcus pneumoniae (12.6%). Furthermore, mixed infection was common because of its high resistance to penicillin. In both groups, S. pneumoniae was more common in younger patients, whereas K. pneumoniae was relatively common in adults. We found no differences in the detection rate by season; however, H. influenzae was frequently isolated in the tonsillar hypertrophy group regardless of seasonal variations. We also found no difference in the antibiotic sensitivity between the two groups; however, strains resistant to penicillin were relatively prevalent and showed a high sensitivity to third-generation cephalosporin. Conclusions: We observed some differences in the types of bacteria in the tonsillar core between the recurrent tonsillitis and tonsillar hypertrophy groups. Our study indicates that essential bacteria have been changing and, thus, we need to change our choice of antibiotics. [source] Isolation of vancomycin-resistant enterococci from pigs in JapanANIMAL SCIENCE JOURNAL, Issue 6 2003Yuri SAKAI ABSTRACT Forty vancomycin-resistant enterococci (VRE) were isolated from feces of pigs in one pig farm. Two strains were further elucidated and these were biochemically identified as Enterococcus faecium possessing the vanB gene. These isolates showed high resistance to vancomycin and nine other antibiotics. This is the first report of VRE contamination in pigs in Japan. [source] Nutrient values of dietary ascorbic acid (l -ascorbyl-2-polyphosphate) on growth, survival and stress tolerance of larval shrimp, Litopenaeus vannameiAQUACULTURE NUTRITION, Issue 2 2009J. NIU Abstract l -ascorbyl-2-polyphosphate (ApP) was used as a vitamin C source to investigate the ascorbic acid (AsA) requirements on growth performance and stress resistance of the larval white shrimp, Litopenaeus vannamei. Five isoenergetic and isonitrogenous fish meal-fish protein hydrolysate-based diets with five levels of ApP, AsA equivalent to 91.8, 188, 271, 360 and 436 mg kg,1 diet were fed to triplicate groups of L. vannamei (mean initial wet weight 1 mg) for 32 days. The diet with AsA 91.8 mg kg,1 showed high cumulative mortality after 10 days of feeding. After the 32-day trial, the shrimp that fed the diet had significantly lower survival and weight gain (WG, %) than those that fed 188, 271, 360 and 436 mg AsA kg,1 diets. Specific growth rate (SGR, % day,1) and final body wet weight (FBW, mg) showed the same pattern as WG (%). There were no significant differences in growth performance (FBW, WG and SGR) among the groups that fed 188, 271, 360 and 436 mg kg,1 of AsA at the termination of feeding trial. Broken-line regression analysis on WG indicated that 191 mg AsA kg,1 in the diet was the optimum for larval L. vannamei. On the contrary, dietary level of more than 360 mg AsA kg,1 was needed to ensure high resistance to stressful conditions such as low dissolved oxygen stressors. [source] Vitamin C requirement of kuruma shrimp postlarvae, Marsupenaeus japonicus (Bate), using l -ascorbyl-2-monophosphate-Na/CaAQUACULTURE RESEARCH, Issue 8 2005Yin Yin Moe Abstract l -ascorbyl-2-monophosphate-Na/Ca (AMP-Na/Ca) was used as a vitamin C source to investigate the ascorbic acid (AsA) requirements on growth performance and stress resistance of the post-larval kuruma shrimp, Marsupenaeus japonicus. Purified carrageenan-microbound diets with six levels of AMP-Na/Ca, AsA equivalent to 0, 20, 56, 87, 759 and 1697 mg kg,1 diet were fed to triplicate groups of M. japonicus (mean initial weight 16±0.3 mg) for 30 days. The diets with AsA 0, 20 and 56 mg kg,1 showed high cumulative mortality after 10 days of feeding. After the 30-day trial, the shrimp fed these diets had significantly lower survival and weight gain (WG, %) than those fed the 87, 759 and 1697 mg AsA kg,1 diets. Specific growth rate and individual dry weight showed the same pattern as WG (%). There were no significant differences in growth performance among the groups fed the AsA levels at 87, 759 and 1697 mg kg,1 at the termination of feeding trial. Broken-line regression analysis indicated that 91.8 mg AsA kg,1 in the diet was the optimum for post-larval shrimp. On the other hand, dietary level of more than 800 mg AsA kg,1 was needed to ensure high resistance to stressful conditions such as osmotic and formalin stressors. [source] | |||||||||||||||||||||||||