40 research outputs found

    A hybrid FV/FD scheme for a novel conservative form of extended Boussinesq equations for waves in porous media

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    International audienceThis paper introduces a conservative form of the extended Boussinesq equations for waves in porous media. This model can be used in both porous and non-porous media since it does not requires any boundary condition at the interface between the porous and non-porous media. A hybrid Finite Volume/Finite Difference (FV/FD) scheme technique is used to solve the conservative form of the extended Boussinesq equations for waves in porous media. For the hyperbolic part of the governing equations, the FV formulation is applied with a Riemann solver of Roe approximation. Whereas, the dispersive and porosity terms are discretized by using FD. The model is validated with experimental data for solitary waves interacting with porous structures and a porous dam break of a one-dimensional flow

    Potential evapotranspiration estimation and its effect on hydrological model response

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    Potential evapotranspiration can be directly calculated by the Penman-Monteith equation, known as the one-step method. The approach requires data on the land cover and related-vegetation parameters based on AVHRR and LDAS information, which are available in recent years. The Nong Son basin, a sub-catchment of the Vu Gia-Thu Bon basin in the Central Vietnam, is selected for this study. To this end, NAM model was used; the results obtained show that the NAM model has the potential to reproduce the effects of potential evapotranspiration on hydrological response. This is seemingly manifested in the good agreement between model simulation of discharge and the observed at the stream gauge

    BISMUTH FILM ELECTRODE FOR MEASUREMENT OF TRACE LEAD BY ADSORPTIVE STRIPPING VOLTAMMETRY WITH CALCEIN BLUE

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    Joint Research on Environmental Science and Technology for the Eart

    Comparison of two hydrological model simulations using NAM and XINANJIANG for Nong Son catchment

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    The study presents the hydrological simulations for the Nong Son catchment, a drainage area of the Vu Gia-Thu Bon basin in the Central Vietnam, by using the NAM and XINANJIANG models. Simulation results for both models show good agreement between calculated and observed discharges at the stream gauge. The overall water balance error is less than ±10%, Nash-Sut cliffe efficiency R2R^2  above 0.85, and Pearson correlation coefficient rr above 0.92 in both model calibration and verification period. Although NAM's performance shows a slightly better correspondence between the discharges at the stream gauge, the XINANJIANG model shows a relatively better reproduction of the runoff components (i.e. overland flow, interflow and baseflow)

    Isolation and identification of indole acetic acid producing bacteria from the coasts of Ben Tre and Tra Vinh Provinces

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    Beneficial plant-growth-promoting bacteria (PGPB) have been reasonably applied to rescue crucial issue for agriculture by salinity soil. Observed most of PGPB was found in endophyte, rhizosphere and soil. Indole acetic acid (IAA)-producing bacteria could naturally stimulate and facilitate plant growth. The knowledge of IAA production and content of bacteria resident in the marine environment has been typically insufficient and limited to date. In recent years, unwarrantable intrusions of sea water have been enlarged in the Mekong River Delta of Vietnam, threatening productive rice fields, local fruits, and cash crops. Therefore, finding PGPB in the coastal regions in the Mekong River Delta as a creative resource for sustainable agriculture is necessary and is a prompt challenge. In this study, IAA-producing bacteria from coastal regions of Ben Tre and Tra Vinh Provinces were isolated and adequately identified. Out of 202 bacterial isolates, 10 isolates showed the possible ability to produce IAA from L-tryptophan. These 10 isolates were objectively evaluated the capacity to produce IAA under 5% (w/v) NaCl in King B and marine broths. The results revealed that IAA production decreased in 5% NaCl, even though bacterial growth increased. These 10 IAA-producing bacteria were classified at the species level, Marinobacter hydrocarbonoclasticus, M. pelagius, M. daepoensis, and Mameliella phaeodactyli by 16S rRNA gene analysis. The most IAA producer in King’s B broth, the isolate C7, was investigated in more detail. The isolate C7 produced the maximum IAA amount (192.2 ± 1.14 µg/ml) under the presence of 20 g/l yeast extract, 2 g/l of L-tryptophan and 1% NaCl. The isolate C7 was able to grow at 1–17% (w/v) NaCl (optimum, 4%), but not in the absence of NaCl, indicating it is a moderate halophilic bacteria. This study highlighted the considerable ability to produce IAA of marine bacteria, which could be thoughtfully considered to use naturally as biofertilizers to promote plant growth in saline intrusion lands.

    The Efficacy and Safety of Hyaluronic Acid Microinjection for Skin Rejuvenation in Vietnam

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    BACKGROUND: Aging is an increasing concern of modern society, particularly facial ageing. In recent years, the microinjection technique has increasingly been emphasised as a skin rejuvenation strategy. Hyaluronic acid (HA) plays an important role in the hydration of the extracellular space and can thus improve skin hydration, firmness and viscoelastic properties. AIM: To evaluate the efficacy and safety of HA microinjection in skin rejuvenation. METHODS: We enrolled thirty participants underwent three sessions of HA microinjection involving multiple injections in the face or back of the hands at 2-week intervals. The aesthetic outcomes were assessed at baseline and after 2, 4 and 8 weeks. Clinical evaluation was based on the Global Aesthetic Improvement Scale (GAIS) and the Wrinkle Severity Rating Scale (WSRS). RESULTS: Evaluation of photographs from 2, 4 and 8 weeks revealed significant clinical improvement in the brightness, texture and wrinkling of the skin. Analysis of the GAIS and WSRS scores revealed statistically significant results after 2 months. CONCLUSION: Most of the participants felt satisfied with the treatment (93.3%)

    Improving Treatment Outcome of Pemphigus Vulgaris on Vietnamese Patients by Using Desmoglein Elisa Test

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    BACKGROUND: Pemphigus Vulgaris (PV) is a chronic disease, is characterized by the presence of flacid bullous in skin and mucosa. There are 2 main autoantibodies against desmoglein3 (Dsg3) and desmoglein1 (Dsg1). AIM: The aims of this study were to evaluate the before and after treatment outcome with corticosteroid, using Desmoglein ELISA test. METHOD: Forty patients with Pemphigus include 36 PV and 4 PF (28 women, 12 women) were enrolled. The titers of Dsg in pemphigus patients by using ELISA test were done before and 1-month treatment RESULTS: Both anti-Dsg1 and anti-Dsg3 levels were significantly reduced after treatment (P < 0.05). The severity of skin lesions was correlated with anti-Dsg1 antibody level and the severity of oral lesions was significantly correlated with anti-Dsg 3 antibody levels (p < 0.05) CONCLUSION: It is recommended that we can predict and improve the outcome of treatment by using Desmoglein ELISA test

    Successful Treatment of Facial Atrophic Acne Scars by Fractional Radiofrequency Microneedle in Vietnamese Patients

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    AIM: The aim of this study was to evaluate the effect of the fractional Radiofrequency microneedle treatment for facial atrophic acne scars. METHODS: A group of 52 patients were recruited for the study. Goodman & Baron’s acne scar grading system was used for assessment at their first visit and at the end of 3 months after the last treatment session. RESULTS: The results displayed that 73.1% of patients have the improvement of the Goodman scar level after four times treatment. The Goodman and Baron scar point mean was reduced from 16 ± 7.6 to 5.6 ± 5.0 (p < 0.01). Post-inflammatory hyperpigmentation was experienced in 5 patients (9.6%). CONCLUSION: The microneedle fractional Radiofrequency is an effective treatment method of facial atrophic acne scars, with minor side effects and a short down-time

    Successful Psoriasis Treatment Using NB-UVB with Methotrexate: The Vietnamese Experience

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    AIM: To compare the effectiveness of narrowband ultraviolet B (NBUVB) and oral methotrexate (MTX) to oral MTX alone in Vietnamese psoriasis patients, from May 2016 to May 2018. METHODS: We conducted a non-randomized trial on 70 patients with plaque-type psoriasis of moderate to severe. Thirty-five patients apply NBUVB once/day in 5 days/week for 4 weeks plus oral MTX 7.5 mg/week and 35 patients oral MTX 7.5 mg/week and both two groups treatment for 3 months. The extent of the lesion was assessed by the Psoriasis Area and Severity Index (PASI). RESULTS: The proportion of decreasing PASI was comparable (68.49% in NBUVB and MTX versus 57.62% in MTX alone); p < 0.05. Inside, good 28.58%, moderate 68.57% and poor 2.85% in NBUVB and MTX better than good 2.85%, moderate 71.4% and poor 25.72% in MTX alone; p < 0.05. The recurrence rate after 24 months of the NBUVB and MTX group (42.9%) was lower than the MTX alone group (71.4%); p < 0.05. CONCLUSION: NBUVB and oral MTX have affected treatment with chronic plaque psoriasis better than oral MTX alone

    The Effectiveness of Narrow Band Uvb (Nb-Uvb) In the Treatment of Pityriasis Lichenoides Chronica (PLC) In Vietnam

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    AIM: This prospective clinical study presents the experiences with NB-UVB monotherapy in the treatment of PLC on Vietnamese patients. METHODS: We enrolled at National Hospital of Dermatology and Venereology (NHDV), Vietnam, 29 PLC patients with generalised disease involving at least 60% of the total body surface (based on Nine’s Rule) and/or failed to respond to other modalities of treatment. Patients were treated with NB-UVB followed the guideline of the psoriatic treatment of AAD-2010, three times weekly. RESULTS: A complete response (CR) was seen in 24 out of 29 PLC patients (82.8%) with a mean cumulative dose of 9760.5 mJ/cm2 after a mean treatment period of 4.6 weeks (13.8 ± 7.4 exposures). Mild side effects were observed: 69% erythema minimum, 55.2% irritation related to dry skin. No severe side effects were seen during the study. No relapses occurred in 24 CR patients within a mean period of 3 months after the last treatment. CONCLUSION: NB-UVB therapy is an effective and safe option for the treatment and management of PLC
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