28 research outputs found

    Deficit Irrigation of Kentucky Bluegrass for Intermountain West Urban Landscapes

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    Due to end users irrigating with excess water, water conservation of turfgrass can make a large impact in urban water conservation by reducing water applied while still maintaining visual appearance. This study was conducted to determine if Kentucky bluegrass (Poapratensis L.) can be deficit irrigated to maintain minimum acceptable appearance while conserving water. The study investigated water stress in terms of stomatal conductance, chlorophyll index, leaf temperature and predawn leaf water potential at the point of water stress, or where visual quality no longer meets expectations during dry down conditions. Water use was measured over well established Kentucky bluegrass with an eddy covariance system that was validated with soil water measurements. Turfgrass was irrigated at 80% of reference evapotranspiration based on allowable depletion of 12 mm of soil water during growing season that was considered to be well-watered. Two dry downs were conducted over a two-year period (early and late summer). Turfgrass was allowed to dry down without irrigation until visual quality reached the minimum acceptable points (score ≤ 6). During drying periods, visual rating, chlorophyll index, predawn leaf water potential, and leaf temperature with stomatal conductance rapidly decreased once stomatal conductance fell to approximately half of well-watered levels. Both soil water content and evapotranspiration had weak correlation with stomatal conductance; however, stomatal conductance tended to have higher correlation with the change in soil moisture than with the change in crop evapotranspiration. Soil water use and eddy covariance data in terms of crop evapotranspiration had high correlation. The plant water use factor ranged from around 0.8 to 1.1 under well-watered condition corresponding to visual rating from 7 to 9. At the minimum acceptable point of visual rating, which is 5.5 to 6, the plant factor ranged from 0.65 to 0.87. This value of plant factor is quite high at this point. Even when Kentucky bluegrass went below acceptable visual quality, the grass still used significant amounts of water with the plant factor value ranging from 0.6 to 0.8. The data suggested that deficit irrigation cannot be applied with Kentucky bluegrass in the Intermountain West area

    Polyphasic evaluation and cytotoxic investigation of isolated cyanobacteria with an emphasis on potent activities of a Scytonema strain

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    DATA AVAILABILITY STATEMENT : The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/supplementary material.Cyanobacteria are phototrophic organisms widely found in most types of natural habitats in the tropical regions of the world. In this study, we isolated and identified cyanobacterial strains from paddy soil in Hanoi (Vietnam) and investigated their cytotoxic activities. Five isolated cyanobacterial strains showed distinctive profiles of gene sequences (rRNA 16S and rbcL), phylogenetic placements, and morphological characteristics. Based on the polyphasic evaluation, they were classified as Scytonema bilaspurense NK13, Hapalosiphon welwitschii MD2411, Aulosira sp. XN1103, Desikacharya sp. NS2000, and Desmonostoc sp. NK1813. The cytotoxic screening revealed that the extract of strain Scytonema bilaspurense NK13 exhibited potent cytotoxic activities against four human cell lines of HeLa cells, OVCAR-8 cells, HaCaT cells, and HEK-293T cells, with IC50 values of 3.8, 34.2, 21.6, and 0.6μg/mL, respectively. This is the first time a well-classified Scytonema strain from tropical habitat in Southeast Asia has been recognized as a potential producer of cytotoxic compounds.The Vietnam National University, Hanoi (VNU).http://www.frontiersin.org/Microbiologyam2023BiochemistryGeneticsMicrobiology and Plant Patholog

    Clinical and Virological Factors Influencing the Performance of a NS1 Antigen-Capture Assay and Potential Use as a Marker of Dengue Disease Severity

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    Dengue is the most prevalent arthropod-borne disease in tropical regions. The clinical manifestation may vary from asymptomatic to potentially fatal dengue shock syndrome. Early laboratory confirmation of dengue diagnosis is essential since many symptoms are not specific. Dengue non-structural protein 1 (NS1) may be used in simple antigen-capture ELISA for early detection of dengue virus infection. Our result demonstrated that the Platelia NS1 antigen detection kit had a quite low overall sensitivity. However, sensitivity rises significantly when used in combination with MAC-ELISA. When taking into account the various forms of dengue infection, the NS1 antigen detection was found relatively high in patients sampled during the first 3 days of fever onset, in patients with primary infection, DENV-1 infection, with high level of viremia and in mild form of dengue fever. In asymptomatically infected individuals, RT-PCR assay has proved to be more sensitive than NS1 antigen detection. Moreover, the NS1 antigen level correlated significantly with high viremia and low level of NS1 antigen was associated with more severe disease

    Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

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    Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42\ub74% vs 44\ub72%; absolute difference \u20131\ub769 [\u20139\ub758 to 6\ub711] p=0\ub767; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5\u20138] vs 6 [5\u20138] cm H2O; p=0\ub70011). ICU mortality was higher in MICs than in HICs (30\ub75% vs 19\ub79%; p=0\ub70004; adjusted effect 16\ub741% [95% CI 9\ub752\u201323\ub752]; p<0\ub70001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0\ub780 [95% CI 0\ub775\u20130\ub786]; p<0\ub70001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status. Funding: No funding

    EFL students’ perspectives on the employment of language learning strategies

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    It is widely acknowledged that language learning strategies (LLSs) are beneficial to learners’ academic achievements, learner autonomy and motivation; however, it is indicated that Vietnamese students, particularly high school students have found it hard to employ LLSs. This paper aims at exploring language learning strategies used by high school students and underlying reasons at a high school located in Ho Chi Minh City. The study involved 238 EFL high school students in responding to a closed-ended questionnaire and twenty of them in answering the semi-structured interview questions. The quantitative data collected from the questionnaire were processed by SPSS version 25.0 in terms of descriptive statistics, and the qualitative data were analyzed by the content-based approach. The results of the study indicated the EFL high school students’ moderate use of LLSs. Remarkably, metacognitive strategies were the most commonly used category, compared to memory strategies – the least employed category. The findings may serve as a guideline for EFL teachers on facilitating high school students’ English language learning. It is also hoped that the results of this study may contribute to the literature about English language learning strategies in EFL contexts

    Evolution of the Graphene Layer in Hybrid Graphene/Silicon Carbide Heterostructures upon Heating

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    The hybrid graphene/SiC model is studied via molecular dynamics simulation to observe the evolution of the graphene layer upon heating. A two-layer model containing 10,000 graphene atoms and 7000 SiC atoms is heated from 50 K to 6000 K via Tersoff and Lennard-Jones potentials. The melting point zone is defined as the temperature range from 4400 K to 4600 K, which is close to the melting zone of graphite in an experiment. The Lindemann criterion for the 2D case is calculated and used to observe the appearance of liquid-like atoms. The evolution upon heating is analyzed on the basis of the occurrence/growth of liquid-like atoms, the radial distribution functions, and the formation of clusters. The liquid-like atoms tend to form clusters, and the largest cluster increases in size slightly to form a single largest cluster of liquid-like atoms

    Molecular mechanisms underlying phenotypic degeneration in Cordyceps militaris: insights from transcriptome reanalysis and osmotic stress studies

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    Abstract Phenotypic degeneration in Cordyceps militaris poses a significant concern for producers, yet the mechanisms underlying this phenomenon remain elusive. To address this concern, we isolated two strains that differ in their abilities to form fruiting bodies. Our observations revealed that the degenerated strain lost the capacity to develop fruiting bodies, exhibited limited radial expansion, increased spore density, and elevated intracellular glycerol levels. Transcriptome reanalysis uncovered dysregulation of genes involved in the MAPK signaling pathway in the degenerate strain. Our RT-qPCR results demonstrated reduced expression of sexual development genes, along with upregulation of genes involved in asexual sporulation, glycerol synthesis, and MAPK regulation, when compared to the wild-type strain. Additionally, we discovered that osmotic stress reduced radial growth but increased conidia sporulation and glycerol accumulation in all strains. Furthermore, hyperosmotic stress inhibited fruiting body formation in all neutralized strains. These findings indicate dysregulation of the MAPK signaling pathway, the possibility of the activation of the high-osmolarity glycerol and spore formation modules, as well as the downregulation of the pheromone response and filamentous growth cascades in the degenerate strain. Overall, our study sheds light on the mechanisms underlying Cordyceps militaris degeneration and identifies potential targets for improving cultivation practices

    Updated estimation of the burden of fungal disease in Vietnam

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    BACKGROUND: Anecdotally, the burden of fungal diseases in Vietnam is rapidly rising, but there has been no updated estimate on this issue since a previous report in 2015.OBJECTIVES: In this study, we aimed at estimating the incidence and prevalence of serious fungal infections for the year 2020.METHODS: We made estimates with a previously described methodology, using reports on the incidence and prevalence of various established risk factors for fungal infections from local, regional or global sources.RESULTS: We estimated 2,389,661 cases of serious fungal infection occurred in Vietnam in 2020. The most common condition was recurrent vaginal candidiasis (4047/100,000 women annually). Among people living with HIV, we estimated 451 cases of cryptococcal meningitis, 1030 of pneumocystis pneumonia, 166 of histoplasmosis and 1612 of talaromycosis annually. Candidaemia incidence was estimated at 12/100,000 population each year. Owing to its high burden of tuberculosis and respiratory diseases, Vietnam had high rates of severe infections caused by Aspergillus species. Incidence of invasive aspergillosis is 24/100,000 population, allergic bronchopulmonary aspergillosis 78/100,000 and severe asthma with fungal sensitisation 102/100,000. Five-year period prevalence of chronic pulmonary aspergillosis is 120/100,000 population /5-year period. Mucormycosis, fungal keratitis and tinea capitis were estimated at 192, 14,431 and 201 episodes each year, respectively.CONCLUSIONS: The number of patients with mycoses in Vietnam is likely underestimated due to a lack of local data and limited diagnostic capacity, but at least 2.5% of the population might have some form of serious fungal disease.</p

    Promoting Respectful Maternity Care by Reducing Unnecessary Episiotomies: Experiences from Centers of Excellence for Breastfeeding in Vietnam

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    (1) Background: Routine episiotomy is not recommended by international guidelines; however, it occurs at a high rate in Vietnam. (2) Methods: A process to reduce unnecessary episiotomies was developed and implemented as part of the Centers of Excellence for Breastfeeding initiative, which aims to deliver high-quality breastfeeding and early essential newborn care services within a supportive policy environment. The aim of this project report is to outline the steps undertaken to reduce episiotomies, the experience in pilot hospitals, and the process towards changing policy. (3) Results: During the 14 months following the change in episiotomy policy, pilot hospital records showed no infant death or injury. Monthly monitoring data from four pilot hospitals showed that the prevalence of episiotomy was substantially lower than the average in national hospitals in Vietnam. Facilitators to reducing the episiotomy rate include the incentive of Centers of Excellence for Breastfeeding designation and supportive hospital leadership. Challenges include the ambiguity of Vietnam’s national guideline on episiotomy and lack of routine monitoring on the episiotomy rate and indications. (4) Discussion: Our experience suggests that through training and routine monitoring hospitals can apply a policy of selective episiotomy and reduce the practice, particularly among multiparous women, and improve breastfeeding rates.(5) Conclusions: Sharing our experience of implementing this process and offering four areas for action will hopefully contribute to expanded use of mother-friendly, evidence-based care as policy and routine practice in Vietnam and similar settings
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