13 research outputs found

    Phytophthora stem rot of purple passionfruit in Vietnam

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    In August 2012 a severe stem rot (stem canker) disease was observed in a purple-fruit variety of passionfruit, Passiflora edulis, in Nghe An province, Vietnam. The stem rot progressed rapidly along the stem affecting branches and fruit, leading to chlorosis, wilting and death of the distal part of the stem. It did not progress below the graft junction into the stem or roots of the rootstock, Passiflora edulis var. flavicarpa. The disease spread within and between plantings causing 100 % loss of some plantings. Phytophthora nicotianae was consistently isolated from diseased tissue and the morphological identification was confirmed by sequencing, and two cultures were deposited in the Murdoch University Culture Collection as MUCC707 and MUCC708. The former culture proved pathogenic in stem inoculations and P. nicotianae was reisolated fulfilling Koch’s postulates. This report represents a new record of Phytophthora stem rot of purple passionfruit in Vietnam

    Oxidize Graphene by UV-Ozone Treatment in Vacuum Chamber

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    As changing graphene properties is vital to promote it as electronic device, we developed graphene modified method with epoxy group by two simple methods: ultraviolet irradiation with various partial oxygen pressures and ultraviolet irradiation under rich oxygen condition with various temperatures. By Hall measurement, the electric mobility in graphene was decreased with increasing temperature during UV-ozone treatment at 50 °C, 80 °C, 100 °C and 120 °C. At low partial oxygen pressure (less than 160 Torr) the oxidation degree is not significant. Additionally, Raman spectroscopy showed the disrupted π-π structure in graphene. Based on the above identification we supposed that epoxy group might establish on graphene surface. © 2016 American Scientific Publishers. All rights reserved1221sciescopu

    Anecic earthworms generate more topsoil than they contribute to erosion – Evidence at catchment scale in northern Vietnam

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    International audienceSoil is considered as a non-renewable resource, which may be lost in sloping land more rapidly than it is formed thus leading to loss of fertility and ecosystem deterioration. We hypothesized that earthworms could counteract this process due to their cast forming activity. To test this hypothesis, we quantified the production of casts in small plots of 0.25 m2 established in three vegetation units (woodland, shrubland and meadow) in a catchment of 46 ha for 2.5 years in relation to their (micro-) pedoclimatic conditions. We also assessed the impact of cast formation on water runoff and soil detachment. Moreover, we quantified the mass of casts deposited in the entire catchment on a regular grid of 50 m and we measured soil erosion at the outlet of the catchment. Our results showed a high and variable production of casts (from 16 to 219 t ha−1 year−1) depending on vegetation, season and year. The mass of casts found in the entire catchment represented on average 7.4 t ha−1 with an annual production rate of 35 t ha−1. Since the annual erosion rate measured for the entire catchment (3 t ha−1 year−1) was much lower than the cast production rate, our results indicated that most of the soil bioturbated by earthworms remained in the catchment. Indeed, water runoff and soil detachment measured in small plots showed that casts were not transported in the water runoff but degraded by raindrop impacts with the material remaining at the place of deposition. This process led to the generating of a new soil horizon at the culmination point of the catchment of up to 6.5 cm after 2.5 years. We conclude that the surface activity of anecic earthworms could influence soil generation at scale and conteract the effects of soil erosion

    Anecic earthworms generate more topsoil than they contribute to erosion – Evidence at catchment scale in northern Vietnam

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    International audienceSoil is considered as a non-renewable resource, which may be lost in sloping land more rapidly than it is formed thus leading to loss of fertility and ecosystem deterioration. We hypothesized that earthworms could counteract this process due to their cast forming activity. To test this hypothesis, we quantified the production of casts in small plots of 0.25 m2 established in three vegetation units (woodland, shrubland and meadow) in a catchment of 46 ha for 2.5 years in relation to their (micro-) pedoclimatic conditions. We also assessed the impact of cast formation on water runoff and soil detachment. Moreover, we quantified the mass of casts deposited in the entire catchment on a regular grid of 50 m and we measured soil erosion at the outlet of the catchment. Our results showed a high and variable production of casts (from 16 to 219 t ha−1 year−1) depending on vegetation, season and year. The mass of casts found in the entire catchment represented on average 7.4 t ha−1 with an annual production rate of 35 t ha−1. Since the annual erosion rate measured for the entire catchment (3 t ha−1 year−1) was much lower than the cast production rate, our results indicated that most of the soil bioturbated by earthworms remained in the catchment. Indeed, water runoff and soil detachment measured in small plots showed that casts were not transported in the water runoff but degraded by raindrop impacts with the material remaining at the place of deposition. This process led to the generating of a new soil horizon at the culmination point of the catchment of up to 6.5 cm after 2.5 years. We conclude that the surface activity of anecic earthworms could influence soil generation at scale and conteract the effects of soil erosion

    Micronized progesterone plus dydrogesterone versus micronized progesterone alone for luteal phase support in frozen-thawed cycles (MIDRONE): a prospective cohort study

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    Study Question: Does the addition of oral dydrogesterone to vaginal progesterone as luteal phase support improve pregnancy outcomes during frozen embryo transfer (FET) cycles compared with vaginal progesterone alone? Summary Answer: Luteal phase support with oral dydrogesterone added to vaginal progesterone had a higher live birth rate and lower miscarriage rate compared with vaginal progesterone alone. What is Known Already: Progesterone is an important hormone that triggers secretory transformation of the endometrium to allow implantation of the embryo. During IVF, exogenous progesterone is administered for luteal phase support. However, there is wide inter-individual variation in absorption of progesterone via the vaginal wall. Oral dydrogesterone is effective and well tolerated when used to provide luteal phase support after fresh embryo transfer. However, there are currently no data on the effectiveness of luteal phase support with the combination of dydrogesterone with vaginal micronized progesterone compared with vaginal micronized progesterone after FET. Study Design Size, Duration: Prospective cohort study conducted at an academic infertility center in Vietnam from 26 June 2019 to 30 March 2020. Participants/Materials, Settings, Methods: We studied 1364 women undergoing IVF with FET. Luteal support was started when endometrial thickness reached 8 mm. The luteal support regimen was either vaginal micronized progesterone 400 mg twice daily plus oral dydrogesterone 10 mg twice daily (second part of the study) or vaginal micronized progesterone 400 mg twice daily (first 4 months of the study). In women with a positive pregnancy test, the appropriate luteal phase support regimen was continued until 7 weeks’ gestation. The primary endpoint was live birth after the first FET of the started cycle, with miscarriage <12 weeks as one of the secondary endpoints. Main Results and the Role of Chance: The vaginal progesterone + dydrogesterone group and vaginal progesterone groups included 732 and 632 participants, respectively. Live birth rates were 46.3% versus 41.3%, respectively (rate ratio [RR] 1.12, 95% CI 0.99–1.27, P¼0.06; multivariate analysis RR 1.30 (95% CI 1.01–1.68), P¼0.042), with a statistically significant lower rate of miscarriage at <12 weeks in the progesterone + dydrogesterone versus progesterone group (3.4% versus 6.6%; RR 0.51, 95% CI 0.32–0.83; P¼0.009). Birth weight of both singletons (2971.0§628.4 versus 3118.8§559.2 g; P¼0.004) and twins (2175.5§494.8 versus 2494.2§584.7; P¼0.002) was significantly lower in the progesterone plus dydrogesterone versus progesterone group. Limitations, Reasons for Caution: The main limitations of the study were the open-label design and the non-randomized nature of the sequential administration of study treatments. However, our systematic comparison of the two strategies was able to be performed much more rapidly than a conventional randomized controlled trial. In addition, the single ethnicity population limits external generalizability. Wider Implications of the Findings: Our findings study suggest a role for oral dydrogesterone in addition to vaginal progesterone as luteal phase support in FET cycles to reduce the miscarriage rate and improve the live birth rate. Carefully planned prospective cohort studies with limited bias could be used as an alternative to randomized controlled clinical trials to inform clinical practice.Lan N. Vuong, Toan D. Pham, Khanh T.Q. Le, Trung T. Ly, Ho L. Le, Diem T.N. Nguyen, Vu N.A. Ho, Vinh Q. Dang, Tuan H. Phung, Robert J. Norman, Ben W. Mol, and Tuong M. H

    Novel Rinse Liquid for sub-90nm Lithography

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    Dissolved rare earth elements distribution in the Solomon Sea

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    International audienceTrace Elements and Isotopes (TEIs) were measured as part of the GEOTRACES PANDORA cruise (July-August 2012, R/V L'Atalante), among them Rare Earth Elements (REEs) as pertinent tracers of land-ocean inputs and water mass transformations. This work discusses results of 19 dissolved REE (dREE) profiles measured using a trispike method in the Coral Sea and inside and at the exits of the Solomon Sea, a semi-enclosed sea with complex topography and straits. Overall, dREEs-except the insoluble Ce-show nutrient like profiles, i.e. depleted at the surface and enriched at depth. Illustrative Nd concentrations range from~5 pmol/kg at the surface to > 25 pmol/kg at 5000 m depth. However, local dREE enrichments are observed, mostly in the Straits (Indispensable, Solomon and Vitiaz Straits) and along the island coasts. A box model allows calculating and discussing the fate of the dREEs in the different water layers flowing through the Solomon Sea. Finally, subtle variations revealed by La, Ce, Eu anomalies and the normalized light versus heavy REE ratio (expressed as Nd n / Yb n) allows the identification of specific mechanisms affecting the distribution of the different dREEs. The positive Eu anomaly observed in the surface layers reflects the basaltic origin of external inputs, consistent with the intensive weathering and/or volcanic activity affecting the surrounding islands. These data also confirm that the distributions of heavy dREEs (like Yb) are better correlated to the dSi concentrations than that of the other REEs

    Sero-prevalence of sars-cov-2 antibodies in high-risk populations in vietnam

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    As a response to the coronavirus disease 2019 (COVID-19) pandemic, Vietnam enforced strict quarantine, contact tracing and physical distancing policies resulting in one of the lowest numbers of individuals infected with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) globally. This study aimed to determine the prevalence of SARS-CoV-2 antibody positivity among high-risk populations in Vietnam. A prevalence survey was undertaken within four communities in Vietnam, where at least two COVID-19 cases had been confirmed. Participants were classified according to the location of exposure: household contacts, close contacts, community members, and healthcare workers (HCWs) responsible for treating COVID-19 cases. Participants completed a baseline questionnaire and SARS-CoV-2 IgG antibodies were quantified using a commercial assay. A total of 3049 community members and 149 health care workers consented to the study. Among 13 individuals who were seropositive (0.4%), five household contacts (5/27, 18.5%), one close contact (1/53, 1.9%), and seven community members (7/2954, 0.2%) had detectable SARS-CoV-2 antibodies. All HCWs were negative for SARS-CoV-2 antibodies. Participants were tested a median of 15.1 (interquartile range from 14.9 to 15.2) weeks after exposure. Our study found a low prevalence of SARS-CoV-2 antibodies in high-risk communities and healthcare workers in communities in Vietnam with known COVID-19 cases
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