15 research outputs found

    Investigation of factors in improving Agrobacterium-mediated gene transfer in Ruellia tuberosa L. and evaluation of α-glucosidase inhibitory activity in established hairy roots

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    Ruellia tuberosa (family Acanthaceae) is widely known in traditional medicine in Asian countries for the treatment of diabetes and other diseases. Its roots were demonstrated to possess a hypoglycemic ability in diabetic animal models. In this study, an original induced procedure was investigated to establish hairy root (HR) from R. tuberosa. With the aim of increasing the transformation rate, some induced factors (acetosyringone (AS) dosage, type of explant, age, infection time, bacterial density, co-cultivation duration) were individually examined. As a result, an improved procedure was implemented: ten-day-old in vitro cotyledon explants were injured and then immersed in the bacterial suspension (OD600 nm = 0.4) added 200 µM AS during 10 min. The infected explants were co-cultivated for 4 days in the Murashige & Skoog (MS) medium before transferring to the medium containing cefotaxime for bacterial elimination. After thirty days of culture, the improved procedure revealed a synergistic effect by enhancing the rooting rate and number of secondary roots per explant up to 4.4- and 8.0-fold, respectively, in comparison with the original procedure. The R. tuberosa HR was then cultured in liquid MS medium and achieved the highest biomass production at the late exponential growth phase (3rd week). Its ethanol extract was also higher 2.0-fold in α-glucosidase inhibitory activity than that of the natural root. In conclusion, the α-glucosidase inhibitory activity of HR inducing by the improved procedure may offer an effective and reliable substitute for the utilization of this herbal plant

    Clinical features, antimicrobial susceptibility patterns and genomics of bacteria causing neonatal sepsis in a children's hospital in Vietnam: protocol for a prospective observational study.

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    INTRODUCTION: The clinical syndrome of neonatal sepsis, comprising signs of infection, septic shock and organ dysfunction in infants ≤4 weeks of age, is a frequent sequel to bloodstream infection and mandates urgent antimicrobial therapy. Bacterial characterisation and antimicrobial susceptibility testing is vital for ensuring appropriate therapy, as high rates of antimicrobial resistance (AMR), especially in low-income and middle-income countries, may adversely affect outcome. Ho Chi Minh City (HCMC) in Vietnam is a rapidly expanding city in Southeast Asia with a current population of almost 8 million. There are limited contemporary data on the causes of neonatal sepsis in Vietnam, and we hypothesise that the emergence of multidrug resistant bacteria is an increasing problem for the appropriate management of sepsis cases. In this study, we aim to investigate the major causes of neonatal sepsis and assess disease outcomes by clinical features, antimicrobial susceptibility profiles and genome composition. METHOD AND ANALYSIS: We will conduct a prospective observational study to characterise the clinical and microbiological features of neonatal sepsis in a major children's hospital in HCMC. All bacteria isolated from blood subjected to whole genome sequencing. We will compare clinical variables and outcomes between different bacterial species, genome composition and AMR gene content. AMR gene content will be assessed and stratified by species, years and contributing hospital departments. Genome sequences will be analysed to investigate phylogenetic relationships. ETHICS AND DISSEMINATION: The study will be conducted in accordance with the principles of the Declaration of Helsinki and the International Council on Harmonization Guidelines for Good Clinical Practice. Ethics approval has been provided by the Oxford Tropical Research Ethics Committee 35-16 and Vietnam Children's Hospital 1 Ethics Committee 73/GCN/BVND1. The findings will be disseminated at international conferences and peer-reviewed journals. TRIAL REGISTRATION NUMBER: ISRCTN69124914; Pre-results

    Collaborative Filtering by Co-Training Method

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    Reliability Evaluation of a Hexacopter-Based Flight Module of a Tethered Unmanned High-Altitude Platform

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    This article discusses a model on the basis of a multidimensional Markov process applied for evaluation of the reliability characteristics of a tethered multirotor high-altitude platform based on a hexacopter. The proposed model takes into account the increase in the functional load after the failure of an element on the remaining operating ones, and also takes into account the location of the failed elements. © 2019, Springer Nature Switzerland AG

    The role of state forest enterprises in the payments for forest environmental services programme in Vietnam

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    To promote pro-poor payments for environmental services, it is necessary to identify institutional options that reduce transaction costs and organisational problems associated with establishing and maintaining contracts with small-scale environmental service providers. This study examined the dual functionality of state forest enterprises (SFEs) in the implementation of the Payments for Forest Environmental Services (PFES) Program in Vietnam. We considered whether SFEs’ involvement in the programme could reduce transaction costs and organisational problems. Data were collected from Tu Ly SFE in Hoa Binh province, northern Vietnam and from implementing agencies at various institutional levels. A survey of households participating in the SFE loan programme, and two stakeholder workshops were executed in 2014. The results revealed that Tu Ly SFE plays an important role in the livelihood of many farmers. A SWOT analysis exhibited SFEs’ advantage over other state agencies in implementing national forest management programmes as there are fewer parties involved with greater autonomy and outreach in the district. This study proposes the acknowledgment of SFEs as environmental service providers in their own forestlands and to use SFEs as intermediaries in the Payments for Forest Environmental Services Programme activities

    Вплив концентрації графенових нанопластинок на теплопровідність силіконової термопасти

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    Ми повідомляємо про ефективний шлях до підвищення теплопровідності силіконової термопасти без погіршення її сумісності за рахунок використання високої теплопровідності та механічної гнучкості/пластичності графенових матеріалів. Силіконові термопасти, що містять графенові нанопластинки (ГНП), готувалися із застосуванням високоенергетичного помелу в кульовому млині. Зображення СЕМ показали, що ГНП були добре дисперговані у базовій термопасті. Досліджена теплопровідність термопасти. Отримані результати показали, що ГНП ефективні для підвищення теплопровідності термопаст. Найвище підвищення теплопровідності до 59 % було отримано для термопасти, що містить 0,75 об. % ГНП. Таке підвищення можна віднести до високої теплопровідності ГНП, хорошої сумісності та рівномірного диспергування ГНП у термопасті. Теплопровідність термопасти з більш високою концентрацією ГНП 1 об. % зменшувалася за рахунок утворення кластерів ГНП. Використовуючи модель Чу з підбором міжфазної термостійкості (Rk), ми виявили, що підвищення теплопровідності термопасти стосується термостійкості Rk між ГНП та матрицею термопасти. Найкращий спосіб поліпшити теплопровідність термопасти – це зменшити Rk. Отримані результати продемонстрували переваги ГНП в термопастах для розсіювання тепла в електронних пристроях високої потужності.We herein report a facile route to improve the thermal conductivity of silicone thermal grease without deteriorating its conformability via exploitation of outstanding thermal conductivity and mechanical flexibility/ductility of graphene materials. The silicone thermal greases containing GNPs were prepared by using the high-energy ball milling process. The SEM images proved that GNPs were well dispersed in the base grease. The thermal conductivity of the thermal greases was investigated and presented. The obtained results demonstrated that GNPs are efficient for the thermal conductivity enhancement of the thermal grease. The highest thermal conductivity enhancement up to 59 % was obtained with the grease containing 0.75 vol. % GNPs. The enhancement could be attributed to high thermal conductivity of GNPs, the good compatibility and uniform dispersion of GNPs in the thermal grease. The thermal conductivity of the thermal grease with higher GNPs concentration of 1 vol. % was decreased due to the formation of GNPs clusters. By using Chu’s model with the interfacial thermal resistance (Rk) fitting, we found that the thermal conductivity enhancement of the thermal grease concerns to the Rk between GNPs and the grease matrix. The best way to improve the thermal conductivity of the thermal grease is to reduce the Rk. The obtained results demonstrated the advantages of GNP in the thermal greases for the heat dissipation in high power electronic devices

    Clinical and laboratory factors associated with neonatal sepsis mortality at a major Vietnamese children’s hospital

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    Sepsis is a major cause of neonatal mortality and children born in low- and middle-income countries (LMICs) are at greater risk of severe neonatal infections than those in higher-income countries. Despite this disparity, there are limited contemporaneous data linking the clinical features of neonatal sepsis with outcome in LMICs. Here, we aimed to identify factors associated with mortality from neonatal sepsis in Vietnam. We conducted a prospective, observational study to describe the clinical features, laboratory characteristics, and mortality rate of neonatal sepsis at a major children’s hospital in Ho Chi Minh City. All in-patient neonates clinically diagnosed with probable or culture-confirmed sepsis meeting inclusion criteria from January 2017 to June 2018 were enrolled. We performed univariable analysis and logistic regression to identify factors independently associated with mortality. 524 neonates were recruited. Most cases were defined as late-onset neonatal sepsis and were hospital-acquired (91.4% and 73.3%, respectively). The median (IQR) duration of hospital stay was 23 (13–41) days, 344/524 (65.6%) had a positive blood culture (of which 393 non-contaminant organisms were isolated), and 69/524 (13.2%) patients died. Coagulase-negative staphylococci (232/405; 57.3%), Klebsiella spp. (28/405; 6.9%), and Escherichia coli (27/405; 6.7%) were the most isolated organisms. Sclerema (OR = 11.4), leukopenia 4 mmol/L (OR = 3.4), extremely low birth weight (OR = 3.2), and hyperglycaemia >180 mg/dL (OR = 2.6) were all significantly (p<0.05) associated with mortality. The identified risk factors can be adopted as prognostic factors for the diagnosis and treatment of neonatal sepsis and enable early risk stratification and interventions appropriate to reduce neonatal sepsis in LMIC settings
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