150 research outputs found

    Hydrothermally Produced Cobalt Oxide Nanostructures at Different Temperatures and Effect on Phase Transition Temperature and Threshold Voltage of Nematic Liquid Crystal Host

    Get PDF
    In this study, cobalt oxide Co3O4 nanostructured material is synthesized by hydrothermal method by using different concentration of cobalt acetate salt at unique hydrothermal reaction time for five different hydrothermal reaction temperatures 105, 120, 140, 160, and 180°C. The obtained nanoparticles are annealed at 300°C for 5 h. Co3O4 nanostructures are determined by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis spectroscopy. The hydrothermally produced samples were reannealed at 550°C, and morphological and structural properties were investigated deeply again. The effect of annealing temperature on morphologies and crystalline structure of cobalt oxide nanoparticle (NP) was also investigated. Nanopyramids and nanorods are two main morphologically obtained structures from the hydrothermal experiment. Nematic liquid crystal mixture E7 is doped with Co3O4 nanorod. Phase transition and threshold voltage of pure and Co3O4 NP-doped E7 LC are examined successfully. It reveals that for Co3O4 NP-doped E7 phase transition temperature and threshold voltage increased very slightly

    \u3ci\u3eNeofusicoccum luteum\u3c/i\u3e as a Pathogen on Tejocote (\u3ci\u3eCrataegus mexicana\u3c/i\u3e)

    Get PDF
    Tejocote (Crataegus mexicana), a small pome crab-apple-like fruit, is becoming economically important in California with increasing production, so consideration of diseases that hinder the yield is important. Diseased trees of tejocote were observed in four orchards of Riverside and San Diego Counties of California. Ten symptomatic/asymptomatic samples were studied from each of the orchards. Five most frequently isolated fungi were identified on the basis of morphological characters and sequence data of the internal transcribed spacer ITS1-5.8SITS2 and partial β-tubulin gene. Three isolates were identified as Neofusicoccum luteum and two as Phomopsis sp. Pathogenicity tests were conducted by inoculating detached shoots of healthy tejocote trees. Significant lesions were observed on all shoots inoculated with the three N. luteum isolates (designated UCR1190, UCR1191, and UCR1192), but not on the shoots inoculated with other isolates or the non-inoculated controls. Results indicated that all three N. luteum isolates are aggressive pathogens on tejocote. This pathosystem should be further studied with a goal of designing appropriate disease management strategies

    Altın Nanoparçacıklarla Katkılandırılan Nematik Sıvı Kristallerin İncelenmesi

    Get PDF
    Bu çalışmada E7 kodlu nematik sıvı kristal karışım altın nanoparçacıklar ile katkılandırılmıştır. Saf, %3 ve %12 altın nanoparçacıklar (ANP) ile katkılandırılan E7 nematik sıvı kristal karışımının elektriksel ve optiksel özellikleri incelenmiştir. Katkılandırılan ANP ile E7’ nin eşik voltajının düştüğü, dielektrik anizotropisinin arttığı ve optik anizotropisini değiştirdiği gözlemlenmiştir. Bu özelliklerin değişmesiyle sıvı kristal numunenin elektro-optik özellikleri altın nanoparçacık katkılandırma ile iyileşmiştir

    Association of Spores of «Phaeomoniella chlamydospora», «Phaeoacremonium inflatipes», and «Pm. aleophilum» with Grapevine Cordons in California

    Get PDF
    Esca (black measles) of grapevine has long been known to occur wherever grapes are grown. Phaeomoniella chlamydospora and two species of Phaeoacremonium, Pm. inflatipes and Pm. aleophilum, have been associated with esca and Petri grapevine decline in major production regions of California. Though present in symptomatic grapevines and capable of causing foliar symptoms of esca, Phaeomoniella chlamydospora does not cause the typical symptoms on fruit. However, trapping studies showed that spores of Pa. chlamydospora, Pm. inflatipes and Pm. aleophilum were captured throughout the year in vineyards ranging from the north California coast to the southern San Joaquin Valley. They can be considered airborne fungi capable of being water-splashed by pruning or other wounds during part of their biological cycle. Trapping of spores coincided with rainfall events for Pa. chlamydospora and Pm. inflatipes, and to a lesser degree for Pm. aleophilum. However, this last species was trapped during periods of time when rainfall did not occur and was trapped longer into the summer

    Identification of Species of Botryosphaeriaceae Causing Bot Gummosis in Citrus in California

    Get PDF
    Members of the Botryosphaeriaceae family are known to cause Bot gummosis on many woody plants worldwide. To identify pathogens associated with Bot gummosis on citrus in California, scion and rootstock samples were collected in 2010 and 2011 from five citrusgrowing counties in California. Symptoms observed on citrus included branch cankers, dieback, and gumming. Various fungal species were recovered from necrotic tissues of branch canker and rootstock samples. Species were identified morphologically and by phylogenetic comparison as ‘Eureka’ lemon, ‘Valencia’, ‘Washington Navel’, ‘Fukumoto’, grapefruit, ‘Satsuma’, and ‘Meyer’ lemon. Species were identified morphologically and by phylogenetic comparison of the complete sequence of the internal transcribed spacer regions, β-tubulin gene, and elongation factor α-1 genes with those of other species in GenBank. A consensus-unrooted most parsimonious tree resulting from multigene phylogenetic analysis showed the existence of three major clades in the Botryosphaeriaceae family. In total, 74 isolates were identified belonging to the Botryosphaeriaceae family, with Neofusicoccum spp., Dothiorella spp., Diplodia spp., (teleomorph Botryosphaeria), Lasiodiplodia spp., and Neoscytalidium dimidiatum (teleomorphs unknown) accounting for 39, 25, 23, 10, and 3% of the total, respectively. On inoculated Eureka lemon shoots, lesion length was significantly different (P \u3c 0.05) among 14 isolates recovered from portions of cankered tissues of the original trees. Lesion lengths were significantly longer (P \u3c 0.05) for shoots inoculated with isolates of Neofusicoccum luteum and shorter for shoots inoculated with isolates of Dothiorella viticola (P \u3c 0.05) than those of other species. Identifying the distribution and occurrence of these fungal pathogens associated with Bot gummosis is useful for management applications during occasional outbreaks in California

    Rootstock Susceptibility to «Phaeomoniella chlamydospora» and «Phaeoacremonium» spp.

    Get PDF
    Twenty healthy cuttings each were inoculated artificially with Phaeomoniella chlamydospora, Phaeoacremonium inflatipes and Phaeoacremonium aleophilum. After the formation of callus, they were planted in pots. Approximately one year after inoculation, disease occurrence was recorded as the length of brown vascular streaking from the base of plant toward the shoot tip. Discolored areas were cultured on potato dextrose agar amended with tetracycline hydrochloride (PDA-tet) and pathogens were re-isolated. Inoculation with Pa. chlamydospora showed that rootstocks 3309, 420A, 110R, 5C, Schwarzmann, St. George, and Salt Creek were least susceptible, while 99R, 39-16, Freedom, Riparia Gloire, 140Ru, 16-16 and 1103 were most susceptible. When inoculated with Pm. inflatipes, 16-16, 3309, AXR1, Salt Creek, 110R, 5C, Freedom and 140Ru were least susceptible, while 420A, St. George, 161-49, and Harmony were most susceptible. Inoculation with Pm. aleophilum showed that 1103, 420A, Harmony, and Salt Creek were least susceptible, while 110R, SO4, 39-16 and 161-49 were most susceptible. The susceptibility of the rootstocks and the occurrence of vine decline in the field in California did not appear to be well correlated because 3309, 101-14, 5C, and 110R were always most susceptible. But these rootstocks are the most widely planted, and hence the natural occurrence of the disease is probably skewed towards these rootstocks. However, since no resistance was detected in our study, even though there was a wide range of susceptibility, the degree of rootstock susceptibility may not be such an important factor in disease expression under natural conditions

    Neofusicoccum luteum as a pathogen on Tejocote (Crataegus mexicana)

    Get PDF
    Tejocote (Crataegus mexicana), a small pome crab-apple-like fruit, is becoming economically important in California with increasing production, so consideration of diseases that hinder the yield is important. Diseased trees of tejocote were observed in four orchards of Riverside and San Diego Counties of California. Ten symptomatic/asymptomatic samples were studied from each of the orchards. Five most frequently isolated fungi were identified on the basis of morphological characters and sequence data of the internal transcribed spacer ITS1-5.8S-ITS2 and partial β-tubulin gene. Three isolates were identified as Neofusicoccum luteum and two as Phomopsis sp. Pathogenicity tests were conducted by inoculating detached shoots of healthy tejocote trees. Significant lesions were observed on all shoots inoculated with the three N. luteum isolates (designated UCR1190, UCR1191, and UCR1192), but not on the shoots inoculated with other isolates or the non-inoculated controls. Results indicated that all three N. luteum isolates are aggressive pathogens on tejocote. This pathosystem should be further studied with a goal of designing appropriate disease management strategies

    Recovery of «Phaemoniella chlamydospora» and «Phaeoacremonium inflatipes» from Soil and Grapevine Tissues

    Get PDF
    Rose Bengal Chloramphenicol Agar (RBCA) appears to be a suitable media for isolating Phaeoacremonium spp. and Phaeomoniella chlamydospora from soil, spore traps and plant tissue. Using the soil-plate method, populations of these organisms were recovered from the soil and surfaces of plant tissue from many different regions of California. In addition, in a few vineyard sites these fungi were recovered from dried plant sap, which had oozed from grapevine girdling wounds and from standing water under grapevine drip systems. RBCA, along with a filtering system, is a useful tool in determining the presence of Petri disease pathogens in vineyard soils, water, and plant tissues. This research presents the first report of the recovery of Phaeoacremonium inflatipes from soil and standing water under grapevines
    corecore