BACKGROUND Metabolic dysfunction-associated fatty liver disease(MAFLD)is a recently proposed term that highlights the role of metabolic dysfunction in hepatic steatosis.It currently affects more than one-third of adul...BACKGROUND Metabolic dysfunction-associated fatty liver disease(MAFLD)is a recently proposed term that highlights the role of metabolic dysfunction in hepatic steatosis.It currently affects more than one-third of adults worldwide and is associated with liver fibrosis,hepatocellular carcinoma,cardiovascular disease,and chronic kidney disease.Given its high prevalence,asymptomatic progression,and revised definition,evaluating its epidemiology and risk profile remains an important public health priority.AIM To assess the prevalence and characteristics of MAFLD among Vietnamese individuals undergoing health check-ups.METHODS This retrospective study included 331 adults undergoing routine health check-ups at The Health Evaluation and Promotion Center,International University of Health and Welfare Center,Cho Ray Hospital,from June to October 2023.MAFLD was diagnosed based on the 2020 international expert consensus.Data collected included demographic,clinical,laboratory information,and metabolic risk factors from routine health check-up records.Descriptive statistics,χ^(2) tests,and ttests/Mann-Whitney tests were applied as appropriate.Significance was defined as P<0.05.RESULTS MAFLD was identified in 97 of 331 individuals(29.31%).Prevalence was significantly higher in men than women(44.51%vs 14.37%;P<0.001).In females,prevalence increased sharply after age 50(P=0.008).According to body mass index groups,prevalence was 0%(underweight),9.27%(normal),and 48.26%(overweight/obese).The MAFLD group had significantly higher rates of hypertension(19.59%vs 2.99%),dyslipidemia(98.96%vs 89.32%),prediabetes/diabetes(65.98%vs 28.20%),hyperuricemia(64.95%vs 31.19%),and metabolic syndrome(54.64%vs 7.69%)compared to the non-MAFLD group(all P<0.001).CONCLUSION MAFLD is prevalent in Vietnamese adults undergoing health screening.It is strongly associated with sex,age,body mass index,and metabolic disorders,indicating the importance of early detection and integrated management.展开更多
BACKGROUND Hepatocellular carcinoma(HCC),the sixth most common cancer and fourthleading cause of cancer-related mortality globally,imposes a significant burden in Vietnam due to endemic hepatitis B virus(HBV)and hepat...BACKGROUND Hepatocellular carcinoma(HCC),the sixth most common cancer and fourthleading cause of cancer-related mortality globally,imposes a significant burden in Vietnam due to endemic hepatitis B virus(HBV)and hepatitis C virus(HCV)infections.Accurate prognostication is crucial for optimizing treatment and outcomes.Numerous staging systems exist,including the Barcelona Clinic Liver Cancer(BCLC),Hong Kong Liver Cancer(HKLC),cancer of the liver Italian Program(CLIP),Italian Liver Cancer(ITA.LI.CA),Japan Integrated Staging(JIS),Tokyo Score,and model to estimate survival in ambulatory HCC patients(MESIAH).However,their comparative performance in Vietnamese patients remains underexplored.AIM To compare the prognostic accuracy of seven HCC staging systems in predicting survival and identify the optimal model.METHODS This retrospective cohort study included 987 patients with HCC diagnosed at Nhan dan Gia Dinh Hospital,Vietnam,from January 2016 to December 2023.Patients were staged using BCLC,HKLC,CLIP,ITA.LI.CA,JIS,Tokyo score,and MESIAH.Overall survival was analyzed using Kaplan-Meier methods,and prognostic performance was evaluated via the area under the receiver operating characteristic(ROC)curve,Harrell’s concordance index,and calibration plots.RESULTS The HKLC and BCLC systems demonstrated the highest discriminatory ability,with area under the ROC curves of 0.834 and 0.830,respectively,at 12 months and 0.859 for both systems at 36 months.CLIP and ITA.LI.CA exhibited superior calibration,particularly at 36 months.The JIS system consistently showed the poorest discriminatory performance.Subgroup analyses revealed that HKLC maintained strong performance across different viral etiologies(HBV,HCV,non-B-non-C)and treatment modalities(transarterial chemoembolization,surgery,ablation).CONCLUSION The HKLC and BCLC systems showed superior prognostic performance for Vietnamese patients with HCC,supporting HKLC adoption in clinical practice.展开更多
Mangrove forest is always considered an effective barrier to protect habitats from high waves,especially tsunami.Therefore,the estimation of wave energy dissipation is required for disater warning.The aim of this stud...Mangrove forest is always considered an effective barrier to protect habitats from high waves,especially tsunami.Therefore,the estimation of wave energy dissipation is required for disater warning.The aim of this study is to calculate wave attenuation in mangrove areas by combining field survey method and mathematical modeling method.The application area is Cu Lao Dung mangrove forest,Soc Trang,Vietnam.From data measurements of hydrodynamics and mangrove characteristics,the wave attenuation coefficient r,the drag coefficient Cd were determined in mud area,mud-mangrove area and mangrove area.In addition,using WAPROMAN model,the attenuation of wave height is simulated in different cases such as without mangrove,with mangrove,breaking wave effect and wave trunk interaction effect.Both the results from the measured method and the model method show the role of mangroves in reducing wave energy.The results from modeling are smaller than the calculated results.However,both methods tend to be suitable.Such difference required more considerations not only on calculation formulas but also on modeling adjustment.The research clearly demonstrated the effectiveness of mangroves in coastal protection,with wave-trunk interaction becoming the dominant factor in energy dissipation deeper into the forest.For future,extending the study to different mangrove forests and longer time scales could provide a more comprehensive understanding of the role of mangroves in coastal protection across various geographical and temporal contexts.展开更多
Mangrove ecosystems along Vietnam’s coastline face significant degradation due to human activities,despite their crucial role in coastal protection against natural hazards.This study aims to assess the spatial and te...Mangrove ecosystems along Vietnam’s coastline face significant degradation due to human activities,despite their crucial role in coastal protection against natural hazards.This study aims to assess the spatial and temporal changes in mangrove coverage along Vietnam’s southern coast by integrating remote sensing techniques with hydrodynamic model simulations.The research methodology combines the Collect Earth tool analysis of Spot-4 and Planet satellite imagery(2000–2020)with Mike 21-HD two-dimensional(2D)hydrodynamic modeling to evaluate mangrove coverage changes by simulating shoreline erosion.Results analysis reveals that a significant increase of 109.83 ha in mangrove area within Vinh Chau Town of Soc Trang Province during the period 2010–2020,predominantly in the eastern region.Hydrodynamic simulations demonstrate that the coastal zone is primarily influenced by the interaction of nearshore currents,East Sea tides,and seasonal monsoon wave patterns.The model results effectively capture the complex interactions between these hydrodynamic factors and mangrove distribution.These findings not only validate the effectiveness of combining remote sensing and hydrodynamic modeling for mangrove assessment but also provide crucial insights for sustainable coastal ecosystem management.The study’s integrated approach offers a robust framework for monitoring mangrove dynamics and developing evidence-based conservation strategies,highlighting the importance of maintaining these vital ecosystems for coastal protection.展开更多
Rip currents are a significant threat to swimmers worldwide,responsible for numerous drowning incidents each year.In Vietnam,Bai Dai Beach in Cam Ranh Bay,Khanh Hoa Province,has experienced an increase in drowning eve...Rip currents are a significant threat to swimmers worldwide,responsible for numerous drowning incidents each year.In Vietnam,Bai Dai Beach in Cam Ranh Bay,Khanh Hoa Province,has experienced an increase in drowning events due to rip currents in recent years.To address this issue,a comprehensive study was conducted based on developing a depth-averaged 2D hydrodynamic model to simulate rip currents in the Bai Dai-Cam Ranh coast.The HYDIST-2D numerical model was applied to simulate the rip current evolution in space and time for the study area.The results showed that the HYDIST-2D numerical model can accurately predict the location,magnitude,and microstructure of rip currents,including rip current speed,width,and length.The simulation results revealed that the rip current speed is greater during the low tide phase,with an average speed of 0.5 m s^(-1),while during high tide,the rip current speed is lower,around 0.1–0.8 m s^(-1).The width and length of the rip current also vary with the tide phase,with a wider and longer rip current observed during the low tide phase.The results also showed that the rip current speed and microstructure are influenced by the wave features,tide current,and bathymetry of the study area.The present study provides valuable insights into the dynamics of rip currents in the Bai Dai-Cam Ranh coast.The findings can be used to support the management of bathing activities and provide early warnings for potential risks associated with rip currents.展开更多
Rapid industrial growth,urbanization,and agricultural activities have led to the discharge of large volumes of pollutants into coastal environments,raising levels of metals such as arsenic(As),cadmium(Cd),and mercury(...Rapid industrial growth,urbanization,and agricultural activities have led to the discharge of large volumes of pollutants into coastal environments,raising levels of metals such as arsenic(As),cadmium(Cd),and mercury(Hg)in water and sediments.Bivalve molluscs,such as Meretrix lyrata and Saccostrea glomerata can accumulate high amounts of toxic heavy metals in their tissues that pose potential risks to human health.They are frequently used as bioindicators due to their filter-feeding behavior and high accumulation potential.This study evaluates heavy metal accumulation in bivalve molluscs from Northeastern Vietnam,including Quang Ninh Province and Hai Phong City.In this study,a systematic literature review was conducted,combined with a bibliometric analysis,to synthesize and evaluate data on heavy metal accumulation in bivalve molluscs from Northeastern Vietnam.The analysis results showed bio-concentration factors exceeding 1,000 for As,Cd,and Hg in certain species,particularly in samples from Quang Ninh Province.Meanwhile,sediment accumulation factors(BSAF)were lower,suggesting that waterborne pathways predominantly contribute to heavy metal uptake.These findings highlight significant food safety risks due to toxic metal accumulation in seafood resources,emphasizing the urgent need for continuous monitoring and the establishment of local safety standards.The study provides important scientific evidence to support marine environmental management and public health protection.展开更多
Irrigation service defines the responsibilities and rights of irrigation system management agencies,water users,and other parties involved in the irrigation service contract.As a result,the irrigation service must be ...Irrigation service defines the responsibilities and rights of irrigation system management agencies,water users,and other parties involved in the irrigation service contract.As a result,the irrigation service must be clearly specified and updated by crop seasons and by all partners.Given the inherent complexity of the service,this article presents and discusses the development and application of a computer model designed to support the specification of public service levels in rice-based irrigation systems.Applied to the Tu Mai irrigation system,the model has enabled all involved parties to define irrigation service levels through systematic analysis and a thorough consideration of constraints such as water resource characteristics,hydraulic structures,and the operational plans of the irrigation system.The research findings have also helped relevant agencies reach agreements on irrigation service levels for the particular irrigation season of spring 2023,which included one irrigation period for land preparation and five subsequent irrigation periods for rice crops corresponding with a specific schedule for operating the system(discharges and duration)that met the farmers’requests for their farming practices and reduced the loss due to rice crop yield decline at the irrigation system as a whole.Additionally,recommendations for improving irrigation services in the Tu Mai system have been made,including upgrading the head pumping station to accommodate lower water levels in the Cau River,aligning the irrigation schedules of the Water User Associations(WUAs)more flexibly,and strictly supervising water deliveries to ensure safety and fairness.展开更多
Coastal cities in Vietnam face increasing urban flooding vulnerability due to climate change-induced extreme pre-cipitation.This study evaluates the response capacity of urban drainage systems,using Vung Tau City as a...Coastal cities in Vietnam face increasing urban flooding vulnerability due to climate change-induced extreme pre-cipitation.This study evaluates the response capacity of urban drainage systems,using Vung Tau City as a case study.We employed a comprehensive approach,combining Intensity-Duration-Frequency(IDF)curve analysis with hydrodynamic modeling,to assess drainage performance under current and projected rainfall intensities.A significant rainfall event on June 19,2020(54.4 mm in 3 h,peaking at 42 mm/h),which exceeded the 5-year return period design(TCVN 7957:2008),caused widespread flooding(25-50 cm depths).Design rainfall hyetographs for 2,5,and 10-year return periods(TCVN 7957:2008)were developed.Results show that under more extreme scenarios,flooded areas increase significantly,with depths up to 1.05 m in the 10-year scenario and prolonged durations due to stormwater routing through regulatory lakes.The analysis reveals the current infrastructure meets only 64%of the 5-year return period demands and merely 41% for a 10-year period.This research highlights the urgent need for enhanced flood management in Vung Tau and similar coastal cities,suggesting upgrades to drainage capacity,implementation of sustainable urban drainage systems,and improved early warning.These insights are valuable for developing climate-resilient infrastructure.展开更多
Photocatalysis is one of the most capable green energy techniques for sustainable solar-to-chemical energy conversion.However,the speedy recombination of photocarriers remains a critical bottleneck in achieving high p...Photocatalysis is one of the most capable green energy techniques for sustainable solar-to-chemical energy conversion.However,the speedy recombination of photocarriers remains a critical bottleneck in achieving high photocatalytic efficiency.Recent advancements have underscored the pivotal role of internal and external electrostatic fields in regulating charge dynamics within semiconductor systems.This review highlights the emerging strategy of employing non-covalent electrostatic interactions to modulate photocatalytic behavior.Internally,spontaneous polarization within polar or ferroelectric semiconductors facilitates efficient charge separation through built-in electric fields.Externally applied mechanical stress and magnetic fields further augment these effects via piezoelectric and magnetoelectric phenomena,offering dynamic control over carrier transport.Beyond macroscopic fields,subtle non-covalent electrostatic forces,such as hydrogen bonds,van der Waals forces,andπ-πstacking,significantly influence surface adsorption,electronic structure modulation,and interfacial charge transfer processes.Combining these external influences with semiconductor properties,we can develop innovative strategies to stabilize the reactive intermediates and reduce the recombination pathways,improving the practical implications of these synergistic effects in energy conversion and environmental remediation.This review systematically elucidates the mechanistic contributions of internal polarization and external fields to the modulation of non-covalent electrostatic forces in photocatalytic systems.Emphasis is placed on material design strategies that integrate structural polarity,field-responsive behavior,and interfacial engineering to achieve superior photocatalytic performance.Finally,the prospects of non-covalent electrostatic interactions in photocatalysis are discussed,providing insights to guide the rational development of more efficient and sustainable photocatalytic systems.展开更多
Urban flooding in low-lying coastal regions(LCRs)is intensifying due to climate change and sea-level rise;however,the complex interplay of hydrological,climatic,and anthropogenic drivers remains poorly understood.This...Urban flooding in low-lying coastal regions(LCRs)is intensifying due to climate change and sea-level rise;however,the complex interplay of hydrological,climatic,and anthropogenic drivers remains poorly understood.This study investigates the specific meteo-hydrological factors linking climate-induced changes and human activities to the urban flooding event in My Tho City,a vulnerable coastal city in Vietnam's Tien Giang Province,from February 9 to 12,2024.Analyzing historical meteo-hydrological data(rainfall,monsoon winds,river discharge,and water levels),we examined the contributing factors.Our findings reveal that the flooding was predominantly driven by the combination of high astronomical tidal levels and significant water surges.These surges were amplified by northeast monsoon circulation.This situation was compounded by critically low Mekong River discharge during the dry season,which enhanced the inland penetration of tidal effects.Rainfall during the period was minimal and did not contribute significantly.We utilized a filtering technique to differentiate between astronomical tides and non-tidal surges in the water level data.These results provide empirical evidence demonstrating that climate-driven sea-level influences(manifesting as high tides and surges)and anthropogenic alterations to river flow governed the urban flooding dynamics.The study underscores the urgent need for integrated adaptation solutions addressing the complex land-ocean interactions, particularly in the context ofclimate change and relative sea-level rise.展开更多
A dual-support smoothed particle hydrodynamics(DS-SPH)that allows variable smoothing lengths while satisfying the conservations of linear momentum,angular momentum and energy is developed.The present DS-SPH is inspire...A dual-support smoothed particle hydrodynamics(DS-SPH)that allows variable smoothing lengths while satisfying the conservations of linear momentum,angular momentum and energy is developed.The present DS-SPH is inspired by the dual-support,a concept introduced from dual-horizon peridynamics from the authors and applied here to SPH so that the unbalanced interactions between the particles with different smoothing lengths can be correctly considered and computed.Conventionally,the SPH formulation employs either the influence domain or the support domain.The concept of dual-support identifies that the influence domain and the support domain involves the duality and should be simultaneously in the SPH formulation when variable smoothing lengths are used.The DS-SPH formulation can be implemented into conventional SPH codes with minimal changes and also without compromising the computational efficiency.A number of numerical examples involving weakly compressible.fluid are presented to demonstrate the capability of the method.展开更多
Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax v...Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax vietnamensis(P. vietnamensis) in cell suspension culture.Methods: Cell suspension cultures were established from friable calluses derived from leaves and petioles of 3-year-old in-vitro P. vietnamensis plants. The cell suspension cultures were grown in Murashige and Skoog basal media supplemented with various concentrations of KN, benzyl adenine, naphthalene acetic acid, and yeast extract and casein hydrolyzate.Results: All tested factors generated an increase in the cell biomass of P. vietnamensis in suspension culture, but the impact of each varies depended on the factor type, concentration, and incubation period. Addition of 2.0 mg/L KN resulted in the largest biomass increase after 24 d,(57.0 ± 0.9) and(3.1 ± 0.1) mg/m L fresh and dry weight, respectively,whereas addition of benzyl adenine or naphthalene acetic acid produced optimum levels of Panax cell biomass at 1.0 and 1.5 mg/L, respectively. Addition of the elicitor yeast extract led to a 1.4–2.4 fold increase in biomass of P. vietnamensis, while addition of casein hydrolyzate enhanced biomass accumulation 1.8–2.6 fold.Conclusions: The addition of each factor causes significant changes in biomass accumulation of P. vietnamensis. The largest biomass accumulation is from cultures grown in MS media containing 2.0 mg/L KN for 24 d. The outcome of the present study provides new insights into the optimal suspension culture conditions for studies on the in vitro cell biomass production of P. vietnamensis.展开更多
Objective:To compare perceived ill-health and health seeking behavior between two communities affected by the large Nam Theun 2 hydroelectric project in central Lao People’s Democratic Republic(PDR).Methods: Two diff...Objective:To compare perceived ill-health and health seeking behavior between two communities affected by the large Nam Theun 2 hydroelectric project in central Lao People’s Democratic Republic(PDR).Methods: Two different affected areas;Nakai plateaubeing remote,sparcely populated and mountainous,and Xe Bang Fai lowland plains,more densely populated and comparatively affluent were included.Data were obtained from two cross-sectional household-based health and socio-economic surveys.Results:We found pronounced differences in the frequency of self-reported fever,cough,headache and myalgia according to location.On the Nakai plateau,45.1%of the individuals with ill-health report(recall period;2 weeks) went to a local health volunteer compared to only 7.2%in the Xe Bang Fai area(P 【 0.001 ).In Nakai,there were disproportionately more illiterates seeking help from local health volunteers when compared to those who attended at least primary schooling(49.2%versus 17.5%,P 【0.01 ).Self-medication with antimalarials was more common in Xe Bang Fai than on Nakai(32.3%versus 7.0%,P 【 0.001).The mean amount of money spent per health consultation was US $ 1.7 in Nakai and US $ 7.2 in Xe Bang Fai.Conclusion:The observed differences in self-reported ill-health and health seeking behavior among these two Lao communities need to be considered when implementing setting-specific mitigation measures as part of the public health action plan of the Nam Theun 2 hydroelectric project.展开更多
AIM:To report the etiologies,risk factors,treatments,and outcomes of infectious keratitis(IK)at a major Vietnamese eye hospital.METHODS:This is a retrospective review of all cases of IK at Vietnam National Eye Hospita...AIM:To report the etiologies,risk factors,treatments,and outcomes of infectious keratitis(IK)at a major Vietnamese eye hospital.METHODS:This is a retrospective review of all cases of IK at Vietnam National Eye Hospital(VNEH)in Hanoi,Vietnam.Medical histories,demographics,clinical features,microbiological results,and treatment outcomes were reviewed.RESULTS:IK was diagnosed in 1974 eyes of 1952 patients,with ocular trauma being the greatest risk factor for IK(34.2%),frequently resulting from an agriculturerelated injur y(53.3%).The mean duration between symptom onset and presentation to VNEH was 19.3±14.4 d,and 98.7%of patients had been treated with topical antibiotic and/or antifungal agents prior to evaluation at VNEH.Based on smear results of 1706 samples,the most common organisms identified were bacteria(n=1107,64.9%)and fungi(n=1092,64.0%),with identification of both bacteria and fungi in 614(36.0%)eyes.Fifty-five of 374 bacterial cultures(14.7%)and 426 of 838 fungal cultures(50.8%)were positive,with the most commonly cultured pathogens being Pseudomonas aeruginosa,Streptococcus pneumonia,Fusarium spp.,and Aspergillus spp.Corneal perforation and descemetocele developed in 391(19.8%)and 93(4.7%)eyes,respectively.Medical treatment was successful in resolving IK in 50.4%eyes,while 337(17.1%)eyes underwent penetrating or anterior lamellar keratoplasty.Evisceration was performed in 7.1%of eyes,most commonly in the setting of fungal keratitis.CONCLUSION:Ocular trauma is a major risk factor for IK in Vietnam,which is diagnosed in almost 400 patients each year at VNEH.Given this,and as approximately one quarter of the eyes that develop IK require corneal transplantation or evisceration,greater emphasis should be placed on the development of prevention and treatment programs for IK in Vietnam.展开更多
Recent paleobotanical investigations in Vietnam provide a good opportunity to improve our understanding of the biodiversity and paleoclimatic conditions in the geological past of Southeast Asia.Palms(Arecaceae)are a d...Recent paleobotanical investigations in Vietnam provide a good opportunity to improve our understanding of the biodiversity and paleoclimatic conditions in the geological past of Southeast Asia.Palms(Arecaceae)are a diverse family of typical thermophilous plants with a relatively low tolerance for freezing.In this study,we describe well-preserved fossil palm leaves from the Oligocene Dong Ho Formation of Hoanh Bo Basin,northern Vietnam.Characters of the fossil leaves,such as a fan-shaped costapalmate lamina,an unarmed petiole,a costa slightly enlarged at the base that then tapers distally into the blade,and well-preserved amphistomatic leaves with cuticles,suggest that they represent a new fossil species,which we herein designate Sabalites colaniae A.Song,T.Su,T.V.Do et Z.K.Zhou sp.nov.Together with other paleontological and palaeoclimatic evidence,we conclude that a warm climate prevailed in northern Vietnam and nearby areas during the Oligocene.展开更多
The groundwater potential map is an important tool for a sustainable water management and land use planning,particularly for agricultural countries like Vietnam.In this article,we proposed new machine learning ensembl...The groundwater potential map is an important tool for a sustainable water management and land use planning,particularly for agricultural countries like Vietnam.In this article,we proposed new machine learning ensemble techniques namely AdaBoost ensemble(ABLWL),Bagging ensemble(BLWL),Multi Boost ensemble(MBLWL),Rotation Forest ensemble(RFLWL)with Locally Weighted Learning(LWL)algorithm as a base classifier to build the groundwater potential map of Gia Lai province in Vietnam.For this study,eleven conditioning factors(aspect,altitude,curvature,slope,Stream Transport Index(STI),Topographic Wetness Index(TWI),soil,geology,river density,rainfall,land-use)and 134 wells yield data was used to create training(70%)and testing(30%)datasets for the development and validation of the models.Several statistical indices were used namely Positive Predictive Value(PPV),Negative Predictive Value(NPV),Sensitivity(SST),Specificity(SPF),Accuracy(ACC),Kappa,and Receiver Operating Characteristics(ROC)curve to validate and compare performance of models.Results show that performance of all the models is good to very good(AUC:0.75 to 0.829)but the ABLWL model with AUC=0.89 is the best.All the models applied in this study can support decision-makers to streamline the management of the groundwater and to develop economy not only of specific territories but also in other regions across the world with minor changes of the input parameters.展开更多
Black pepper varieties, namely “Vinh Linh”, “Lada”, “An Do” and “Loc Ninh” were planted in three different ecological regions: Dak Lak, Gia Lai and Dong Nai in order to compare the growth ability, productivity...Black pepper varieties, namely “Vinh Linh”, “Lada”, “An Do” and “Loc Ninh” were planted in three different ecological regions: Dak Lak, Gia Lai and Dong Nai in order to compare the growth ability, productivity, and quality of peppercorn. The experiments were designed in the Randomized Complete Block Design (RCBD) with four replications. The results of study have been indicated that “Vinh Linh” and “Lada” both varieties performed better crucial parameters of growth, productivity and yield, after 36 months planted. Although having greater growth parameter in the location of Dong Nai province, four varieties showed lower yield than other regions. By contrast, the four pepper types achieved the highest yield in Gia Lai, followed by Dak Lak. With respect to peppercorn quality, “Vinh Linh”, “Loc Ninh” and “Lada” achieved requirements of Vietnamese Standard (TCVN 7036:2008) including bulk density: 535.69 - 612.72 g/l;piperine: 4.06 - 4.31 g/100g and volatile oil at 2.72 - 3.16 ml/100g. In contrast, “An Do” variety presented the poorest level of piperine (3.78 g/100g), and unachieved requirements.展开更多
The main goal of this study is to use higher-order isogeometric analysis(IGA)to study the dynamic response of sandwich shells with an auxetic honeycomb core and two different functionally graded materials(FGM)skin lay...The main goal of this study is to use higher-order isogeometric analysis(IGA)to study the dynamic response of sandwich shells with an auxetic honeycomb core and two different functionally graded materials(FGM)skin layers(namely honeycomb-FGS shells)subjected to dynamic loading.Touratier's non-polynomial higher-order shear deformation theory(HSDT)is used due to its simplicity and performance.The governing equation is derived from Hamilton's principle.After verifying the present approach,the effect of input parameters on the dynamic response of honeycomb-FGS shells is carried out in detail.展开更多
Heavy metals may induce bacterial antibiotic resistance and affect their growth in the ecosystem.In this study,we aim to determine bacterial growth and antibiotic resistance in the pressure of heavy metals.Observed th...Heavy metals may induce bacterial antibiotic resistance and affect their growth in the ecosystem.In this study,we aim to determine bacterial growth and antibiotic resistance in the pressure of heavy metals.Observed the changing morphology by gram staining was checked for bacterial toleration with heavy metal,developing of the colony form unit(CFU)was analysed bacterial kinetic growths and their biofilm formation.The disk diffusion test was used to perform bacterial susceptibility profiles with Ceftazidime(30μg),Ceftriaxone(30μg),Colistin sulfate(10μg),Meropenem or Imipenem(10μg),Ciprofloxacin(5μg)and Azithromycin(15μg)and the CLSI was applied for interpreting the data.The bacterial morphology remarkably changed from normal to short,round shape at a high concentration of heavy metals after 1 month.Their changing shape adapted to heavy metals by survival growing and resisted to Azithromycin,Ciprofloxacin,and Colistin without biofilm formation after 1 month,that was continued increasing after 2 months.The bacterial growth and antibiotic resistance were significant differences between provinces(P=0.01),type of bacterial species,and concentration of heavy metals.These results indicate that heavy metals are a crucial factor-driven for enhancing bacterial adaptation in pollution water resources and inducing their antimicrobial resistance in the aquatic environment.展开更多
This paper uses isogeometric analysis(IGA)based on higher-order shear deformation theory(HSDT)to study the dynamic response of bio-inspired helicoid laminated composite(B-iHLC)plates resting on Pasternak foundation(PF...This paper uses isogeometric analysis(IGA)based on higher-order shear deformation theory(HSDT)to study the dynamic response of bio-inspired helicoid laminated composite(B-iHLC)plates resting on Pasternak foundation(PF)excited by explosive loading.IGA takes advantage of non-uniform rational Bspline(NURBS)basic functions to exactly represent the structure geometry models and the attainment of higher-order approximation conditions.This method also ensures a C1 continuous function in the analysis of transverse shear deformation via HSDT.Furthermore,IGA eliminates the requirement for correction factors and delivers accurate results.Pasternak foundation with two stiffness parameters:springer stiffness(k_(1))and shear stiffness(k_(2)).The derivation of the governing equations is based on Hamilton's principle.The proposed method is validated through numerical examples.A comprehensive analysis of the impact of geometrical parameters,material properties,boundary conditions(BCs),and foundation stiffness on dynamic response of B-i HLC plates is carried out.展开更多
文摘BACKGROUND Metabolic dysfunction-associated fatty liver disease(MAFLD)is a recently proposed term that highlights the role of metabolic dysfunction in hepatic steatosis.It currently affects more than one-third of adults worldwide and is associated with liver fibrosis,hepatocellular carcinoma,cardiovascular disease,and chronic kidney disease.Given its high prevalence,asymptomatic progression,and revised definition,evaluating its epidemiology and risk profile remains an important public health priority.AIM To assess the prevalence and characteristics of MAFLD among Vietnamese individuals undergoing health check-ups.METHODS This retrospective study included 331 adults undergoing routine health check-ups at The Health Evaluation and Promotion Center,International University of Health and Welfare Center,Cho Ray Hospital,from June to October 2023.MAFLD was diagnosed based on the 2020 international expert consensus.Data collected included demographic,clinical,laboratory information,and metabolic risk factors from routine health check-up records.Descriptive statistics,χ^(2) tests,and ttests/Mann-Whitney tests were applied as appropriate.Significance was defined as P<0.05.RESULTS MAFLD was identified in 97 of 331 individuals(29.31%).Prevalence was significantly higher in men than women(44.51%vs 14.37%;P<0.001).In females,prevalence increased sharply after age 50(P=0.008).According to body mass index groups,prevalence was 0%(underweight),9.27%(normal),and 48.26%(overweight/obese).The MAFLD group had significantly higher rates of hypertension(19.59%vs 2.99%),dyslipidemia(98.96%vs 89.32%),prediabetes/diabetes(65.98%vs 28.20%),hyperuricemia(64.95%vs 31.19%),and metabolic syndrome(54.64%vs 7.69%)compared to the non-MAFLD group(all P<0.001).CONCLUSION MAFLD is prevalent in Vietnamese adults undergoing health screening.It is strongly associated with sex,age,body mass index,and metabolic disorders,indicating the importance of early detection and integrated management.
文摘BACKGROUND Hepatocellular carcinoma(HCC),the sixth most common cancer and fourthleading cause of cancer-related mortality globally,imposes a significant burden in Vietnam due to endemic hepatitis B virus(HBV)and hepatitis C virus(HCV)infections.Accurate prognostication is crucial for optimizing treatment and outcomes.Numerous staging systems exist,including the Barcelona Clinic Liver Cancer(BCLC),Hong Kong Liver Cancer(HKLC),cancer of the liver Italian Program(CLIP),Italian Liver Cancer(ITA.LI.CA),Japan Integrated Staging(JIS),Tokyo Score,and model to estimate survival in ambulatory HCC patients(MESIAH).However,their comparative performance in Vietnamese patients remains underexplored.AIM To compare the prognostic accuracy of seven HCC staging systems in predicting survival and identify the optimal model.METHODS This retrospective cohort study included 987 patients with HCC diagnosed at Nhan dan Gia Dinh Hospital,Vietnam,from January 2016 to December 2023.Patients were staged using BCLC,HKLC,CLIP,ITA.LI.CA,JIS,Tokyo score,and MESIAH.Overall survival was analyzed using Kaplan-Meier methods,and prognostic performance was evaluated via the area under the receiver operating characteristic(ROC)curve,Harrell’s concordance index,and calibration plots.RESULTS The HKLC and BCLC systems demonstrated the highest discriminatory ability,with area under the ROC curves of 0.834 and 0.830,respectively,at 12 months and 0.859 for both systems at 36 months.CLIP and ITA.LI.CA exhibited superior calibration,particularly at 36 months.The JIS system consistently showed the poorest discriminatory performance.Subgroup analyses revealed that HKLC maintained strong performance across different viral etiologies(HBV,HCV,non-B-non-C)and treatment modalities(transarterial chemoembolization,surgery,ablation).CONCLUSION The HKLC and BCLC systems showed superior prognostic performance for Vietnamese patients with HCC,supporting HKLC adoption in clinical practice.
基金funded by Vietnam National University Ho Chi Minh City(VNU-HCM)under grant number B2019-18-09.
文摘Mangrove forest is always considered an effective barrier to protect habitats from high waves,especially tsunami.Therefore,the estimation of wave energy dissipation is required for disater warning.The aim of this study is to calculate wave attenuation in mangrove areas by combining field survey method and mathematical modeling method.The application area is Cu Lao Dung mangrove forest,Soc Trang,Vietnam.From data measurements of hydrodynamics and mangrove characteristics,the wave attenuation coefficient r,the drag coefficient Cd were determined in mud area,mud-mangrove area and mangrove area.In addition,using WAPROMAN model,the attenuation of wave height is simulated in different cases such as without mangrove,with mangrove,breaking wave effect and wave trunk interaction effect.Both the results from the measured method and the model method show the role of mangroves in reducing wave energy.The results from modeling are smaller than the calculated results.However,both methods tend to be suitable.Such difference required more considerations not only on calculation formulas but also on modeling adjustment.The research clearly demonstrated the effectiveness of mangroves in coastal protection,with wave-trunk interaction becoming the dominant factor in energy dissipation deeper into the forest.For future,extending the study to different mangrove forests and longer time scales could provide a more comprehensive understanding of the role of mangroves in coastal protection across various geographical and temporal contexts.
基金supported by Environmental Protection Project 2023-2024,with the Joint Vietnam-Russia Tropical Science and Technology Research Center(Southern Branch)as the lead Institution.
文摘Mangrove ecosystems along Vietnam’s coastline face significant degradation due to human activities,despite their crucial role in coastal protection against natural hazards.This study aims to assess the spatial and temporal changes in mangrove coverage along Vietnam’s southern coast by integrating remote sensing techniques with hydrodynamic model simulations.The research methodology combines the Collect Earth tool analysis of Spot-4 and Planet satellite imagery(2000–2020)with Mike 21-HD two-dimensional(2D)hydrodynamic modeling to evaluate mangrove coverage changes by simulating shoreline erosion.Results analysis reveals that a significant increase of 109.83 ha in mangrove area within Vinh Chau Town of Soc Trang Province during the period 2010–2020,predominantly in the eastern region.Hydrodynamic simulations demonstrate that the coastal zone is primarily influenced by the interaction of nearshore currents,East Sea tides,and seasonal monsoon wave patterns.The model results effectively capture the complex interactions between these hydrodynamic factors and mangrove distribution.These findings not only validate the effectiveness of combining remote sensing and hydrodynamic modeling for mangrove assessment but also provide crucial insights for sustainable coastal ecosystem management.The study’s integrated approach offers a robust framework for monitoring mangrove dynamics and developing evidence-based conservation strategies,highlighting the importance of maintaining these vital ecosystems for coastal protection.
文摘Rip currents are a significant threat to swimmers worldwide,responsible for numerous drowning incidents each year.In Vietnam,Bai Dai Beach in Cam Ranh Bay,Khanh Hoa Province,has experienced an increase in drowning events due to rip currents in recent years.To address this issue,a comprehensive study was conducted based on developing a depth-averaged 2D hydrodynamic model to simulate rip currents in the Bai Dai-Cam Ranh coast.The HYDIST-2D numerical model was applied to simulate the rip current evolution in space and time for the study area.The results showed that the HYDIST-2D numerical model can accurately predict the location,magnitude,and microstructure of rip currents,including rip current speed,width,and length.The simulation results revealed that the rip current speed is greater during the low tide phase,with an average speed of 0.5 m s^(-1),while during high tide,the rip current speed is lower,around 0.1–0.8 m s^(-1).The width and length of the rip current also vary with the tide phase,with a wider and longer rip current observed during the low tide phase.The results also showed that the rip current speed and microstructure are influenced by the wave features,tide current,and bathymetry of the study area.The present study provides valuable insights into the dynamics of rip currents in the Bai Dai-Cam Ranh coast.The findings can be used to support the management of bathing activities and provide early warnings for potential risks associated with rip currents.
文摘Rapid industrial growth,urbanization,and agricultural activities have led to the discharge of large volumes of pollutants into coastal environments,raising levels of metals such as arsenic(As),cadmium(Cd),and mercury(Hg)in water and sediments.Bivalve molluscs,such as Meretrix lyrata and Saccostrea glomerata can accumulate high amounts of toxic heavy metals in their tissues that pose potential risks to human health.They are frequently used as bioindicators due to their filter-feeding behavior and high accumulation potential.This study evaluates heavy metal accumulation in bivalve molluscs from Northeastern Vietnam,including Quang Ninh Province and Hai Phong City.In this study,a systematic literature review was conducted,combined with a bibliometric analysis,to synthesize and evaluate data on heavy metal accumulation in bivalve molluscs from Northeastern Vietnam.The analysis results showed bio-concentration factors exceeding 1,000 for As,Cd,and Hg in certain species,particularly in samples from Quang Ninh Province.Meanwhile,sediment accumulation factors(BSAF)were lower,suggesting that waterborne pathways predominantly contribute to heavy metal uptake.These findings highlight significant food safety risks due to toxic metal accumulation in seafood resources,emphasizing the urgent need for continuous monitoring and the establishment of local safety standards.The study provides important scientific evidence to support marine environmental management and public health protection.
文摘Irrigation service defines the responsibilities and rights of irrigation system management agencies,water users,and other parties involved in the irrigation service contract.As a result,the irrigation service must be clearly specified and updated by crop seasons and by all partners.Given the inherent complexity of the service,this article presents and discusses the development and application of a computer model designed to support the specification of public service levels in rice-based irrigation systems.Applied to the Tu Mai irrigation system,the model has enabled all involved parties to define irrigation service levels through systematic analysis and a thorough consideration of constraints such as water resource characteristics,hydraulic structures,and the operational plans of the irrigation system.The research findings have also helped relevant agencies reach agreements on irrigation service levels for the particular irrigation season of spring 2023,which included one irrigation period for land preparation and five subsequent irrigation periods for rice crops corresponding with a specific schedule for operating the system(discharges and duration)that met the farmers’requests for their farming practices and reduced the loss due to rice crop yield decline at the irrigation system as a whole.Additionally,recommendations for improving irrigation services in the Tu Mai system have been made,including upgrading the head pumping station to accommodate lower water levels in the Cau River,aligning the irrigation schedules of the Water User Associations(WUAs)more flexibly,and strictly supervising water deliveries to ensure safety and fairness.
基金supported by the Ministry of Natural Resources and Environment project 2024.06.04,“Research on the application of artificial intelligence combined with remote sensing in warning of flood risks due to heavy rain and high tides for coastal cities”,grant number 2024.06.04.
文摘Coastal cities in Vietnam face increasing urban flooding vulnerability due to climate change-induced extreme pre-cipitation.This study evaluates the response capacity of urban drainage systems,using Vung Tau City as a case study.We employed a comprehensive approach,combining Intensity-Duration-Frequency(IDF)curve analysis with hydrodynamic modeling,to assess drainage performance under current and projected rainfall intensities.A significant rainfall event on June 19,2020(54.4 mm in 3 h,peaking at 42 mm/h),which exceeded the 5-year return period design(TCVN 7957:2008),caused widespread flooding(25-50 cm depths).Design rainfall hyetographs for 2,5,and 10-year return periods(TCVN 7957:2008)were developed.Results show that under more extreme scenarios,flooded areas increase significantly,with depths up to 1.05 m in the 10-year scenario and prolonged durations due to stormwater routing through regulatory lakes.The analysis reveals the current infrastructure meets only 64%of the 5-year return period demands and merely 41% for a 10-year period.This research highlights the urgent need for enhanced flood management in Vung Tau and similar coastal cities,suggesting upgrades to drainage capacity,implementation of sustainable urban drainage systems,and improved early warning.These insights are valuable for developing climate-resilient infrastructure.
基金the Deputyship for Research and Innovation,“Ministry of Education”in Saudi Arabia for funding this research(IFKSU-HCRA-12-3).
文摘Photocatalysis is one of the most capable green energy techniques for sustainable solar-to-chemical energy conversion.However,the speedy recombination of photocarriers remains a critical bottleneck in achieving high photocatalytic efficiency.Recent advancements have underscored the pivotal role of internal and external electrostatic fields in regulating charge dynamics within semiconductor systems.This review highlights the emerging strategy of employing non-covalent electrostatic interactions to modulate photocatalytic behavior.Internally,spontaneous polarization within polar or ferroelectric semiconductors facilitates efficient charge separation through built-in electric fields.Externally applied mechanical stress and magnetic fields further augment these effects via piezoelectric and magnetoelectric phenomena,offering dynamic control over carrier transport.Beyond macroscopic fields,subtle non-covalent electrostatic forces,such as hydrogen bonds,van der Waals forces,andπ-πstacking,significantly influence surface adsorption,electronic structure modulation,and interfacial charge transfer processes.Combining these external influences with semiconductor properties,we can develop innovative strategies to stabilize the reactive intermediates and reduce the recombination pathways,improving the practical implications of these synergistic effects in energy conversion and environmental remediation.This review systematically elucidates the mechanistic contributions of internal polarization and external fields to the modulation of non-covalent electrostatic forces in photocatalytic systems.Emphasis is placed on material design strategies that integrate structural polarity,field-responsive behavior,and interfacial engineering to achieve superior photocatalytic performance.Finally,the prospects of non-covalent electrostatic interactions in photocatalysis are discussed,providing insights to guide the rational development of more efficient and sustainable photocatalytic systems.
基金supported by the Vietnam National University,Ho Chi Minh City(VNU-HCM)project entitled“Identifying and quantifying drivers causing water level fluctuations in the Vietnamese Mekong Delta”grant number[B2024-18-01].
文摘Urban flooding in low-lying coastal regions(LCRs)is intensifying due to climate change and sea-level rise;however,the complex interplay of hydrological,climatic,and anthropogenic drivers remains poorly understood.This study investigates the specific meteo-hydrological factors linking climate-induced changes and human activities to the urban flooding event in My Tho City,a vulnerable coastal city in Vietnam's Tien Giang Province,from February 9 to 12,2024.Analyzing historical meteo-hydrological data(rainfall,monsoon winds,river discharge,and water levels),we examined the contributing factors.Our findings reveal that the flooding was predominantly driven by the combination of high astronomical tidal levels and significant water surges.These surges were amplified by northeast monsoon circulation.This situation was compounded by critically low Mekong River discharge during the dry season,which enhanced the inland penetration of tidal effects.Rainfall during the period was minimal and did not contribute significantly.We utilized a filtering technique to differentiate between astronomical tides and non-tidal surges in the water level data.These results provide empirical evidence demonstrating that climate-driven sea-level influences(manifesting as high tides and surges)and anthropogenic alterations to river flow governed the urban flooding dynamics.The study underscores the urgent need for integrated adaptation solutions addressing the complex land-ocean interactions, particularly in the context ofclimate change and relative sea-level rise.
基金The authors acknowledge the supports from the ERC-CoG(Computational Modeling and Design of Lithium-ion Batteries(COMBAT)),RISE-BESTOFRAC and National Science Foundation of China(51474157).
文摘A dual-support smoothed particle hydrodynamics(DS-SPH)that allows variable smoothing lengths while satisfying the conservations of linear momentum,angular momentum and energy is developed.The present DS-SPH is inspired by the dual-support,a concept introduced from dual-horizon peridynamics from the authors and applied here to SPH so that the unbalanced interactions between the particles with different smoothing lengths can be correctly considered and computed.Conventionally,the SPH formulation employs either the influence domain or the support domain.The concept of dual-support identifies that the influence domain and the support domain involves the duality and should be simultaneously in the SPH formulation when variable smoothing lengths are used.The DS-SPH formulation can be implemented into conventional SPH codes with minimal changes and also without compromising the computational efficiency.A number of numerical examples involving weakly compressible.fluid are presented to demonstrate the capability of the method.
基金the Ministry of Science and Technology,Vietnam for financial support
文摘Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax vietnamensis(P. vietnamensis) in cell suspension culture.Methods: Cell suspension cultures were established from friable calluses derived from leaves and petioles of 3-year-old in-vitro P. vietnamensis plants. The cell suspension cultures were grown in Murashige and Skoog basal media supplemented with various concentrations of KN, benzyl adenine, naphthalene acetic acid, and yeast extract and casein hydrolyzate.Results: All tested factors generated an increase in the cell biomass of P. vietnamensis in suspension culture, but the impact of each varies depended on the factor type, concentration, and incubation period. Addition of 2.0 mg/L KN resulted in the largest biomass increase after 24 d,(57.0 ± 0.9) and(3.1 ± 0.1) mg/m L fresh and dry weight, respectively,whereas addition of benzyl adenine or naphthalene acetic acid produced optimum levels of Panax cell biomass at 1.0 and 1.5 mg/L, respectively. Addition of the elicitor yeast extract led to a 1.4–2.4 fold increase in biomass of P. vietnamensis, while addition of casein hydrolyzate enhanced biomass accumulation 1.8–2.6 fold.Conclusions: The addition of each factor causes significant changes in biomass accumulation of P. vietnamensis. The largest biomass accumulation is from cultures grown in MS media containing 2.0 mg/L KN for 24 d. The outcome of the present study provides new insights into the optimal suspension culture conditions for studies on the in vitro cell biomass production of P. vietnamensis.
基金financial support was granted by the Swiss National Science Foundationthe Swiss Agency for Development and Cooperation(projects no.3270B0 - 110020 to SS and PO and no.PPOOB - 102883 to TEE and JU)
文摘Objective:To compare perceived ill-health and health seeking behavior between two communities affected by the large Nam Theun 2 hydroelectric project in central Lao People’s Democratic Republic(PDR).Methods: Two different affected areas;Nakai plateaubeing remote,sparcely populated and mountainous,and Xe Bang Fai lowland plains,more densely populated and comparatively affluent were included.Data were obtained from two cross-sectional household-based health and socio-economic surveys.Results:We found pronounced differences in the frequency of self-reported fever,cough,headache and myalgia according to location.On the Nakai plateau,45.1%of the individuals with ill-health report(recall period;2 weeks) went to a local health volunteer compared to only 7.2%in the Xe Bang Fai area(P 【 0.001 ).In Nakai,there were disproportionately more illiterates seeking help from local health volunteers when compared to those who attended at least primary schooling(49.2%versus 17.5%,P 【0.01 ).Self-medication with antimalarials was more common in Xe Bang Fai than on Nakai(32.3%versus 7.0%,P 【 0.001).The mean amount of money spent per health consultation was US $ 1.7 in Nakai and US $ 7.2 in Xe Bang Fai.Conclusion:The observed differences in self-reported ill-health and health seeking behavior among these two Lao communities need to be considered when implementing setting-specific mitigation measures as part of the public health action plan of the Nam Theun 2 hydroelectric project.
文摘AIM:To report the etiologies,risk factors,treatments,and outcomes of infectious keratitis(IK)at a major Vietnamese eye hospital.METHODS:This is a retrospective review of all cases of IK at Vietnam National Eye Hospital(VNEH)in Hanoi,Vietnam.Medical histories,demographics,clinical features,microbiological results,and treatment outcomes were reviewed.RESULTS:IK was diagnosed in 1974 eyes of 1952 patients,with ocular trauma being the greatest risk factor for IK(34.2%),frequently resulting from an agriculturerelated injur y(53.3%).The mean duration between symptom onset and presentation to VNEH was 19.3±14.4 d,and 98.7%of patients had been treated with topical antibiotic and/or antifungal agents prior to evaluation at VNEH.Based on smear results of 1706 samples,the most common organisms identified were bacteria(n=1107,64.9%)and fungi(n=1092,64.0%),with identification of both bacteria and fungi in 614(36.0%)eyes.Fifty-five of 374 bacterial cultures(14.7%)and 426 of 838 fungal cultures(50.8%)were positive,with the most commonly cultured pathogens being Pseudomonas aeruginosa,Streptococcus pneumonia,Fusarium spp.,and Aspergillus spp.Corneal perforation and descemetocele developed in 391(19.8%)and 93(4.7%)eyes,respectively.Medical treatment was successful in resolving IK in 50.4%eyes,while 337(17.1%)eyes underwent penetrating or anterior lamellar keratoplasty.Evisceration was performed in 7.1%of eyes,most commonly in the setting of fungal keratitis.CONCLUSION:Ocular trauma is a major risk factor for IK in Vietnam,which is diagnosed in almost 400 patients each year at VNEH.Given this,and as approximately one quarter of the eyes that develop IK require corneal transplantation or evisceration,greater emphasis should be placed on the development of prevention and treatment programs for IK in Vietnam.
基金supported by National Natural Science Foundation of China(NSFC)(31800183,41922010,42002020,41661134049)Yunnan Basic Research Projects(202001AU070137,2019FB026)+2 种基金Chinese Academy of Sciences"Light of West China"Program(2020000023)the CAS 135 program(2017XTBG-T03)Project“Study,collection of fossil woods in Vietnam for exhibition in System of Vietnam National Museum of Nature”(CT0000.01/19-21).
文摘Recent paleobotanical investigations in Vietnam provide a good opportunity to improve our understanding of the biodiversity and paleoclimatic conditions in the geological past of Southeast Asia.Palms(Arecaceae)are a diverse family of typical thermophilous plants with a relatively low tolerance for freezing.In this study,we describe well-preserved fossil palm leaves from the Oligocene Dong Ho Formation of Hoanh Bo Basin,northern Vietnam.Characters of the fossil leaves,such as a fan-shaped costapalmate lamina,an unarmed petiole,a costa slightly enlarged at the base that then tapers distally into the blade,and well-preserved amphistomatic leaves with cuticles,suggest that they represent a new fossil species,which we herein designate Sabalites colaniae A.Song,T.Su,T.V.Do et Z.K.Zhou sp.nov.Together with other paleontological and palaeoclimatic evidence,we conclude that a warm climate prevailed in northern Vietnam and nearby areas during the Oligocene.
基金funded by Vietnam National Foundation for Science and Technology Development(NAFOSTED)under grant number 105.08-2019.03.
文摘The groundwater potential map is an important tool for a sustainable water management and land use planning,particularly for agricultural countries like Vietnam.In this article,we proposed new machine learning ensemble techniques namely AdaBoost ensemble(ABLWL),Bagging ensemble(BLWL),Multi Boost ensemble(MBLWL),Rotation Forest ensemble(RFLWL)with Locally Weighted Learning(LWL)algorithm as a base classifier to build the groundwater potential map of Gia Lai province in Vietnam.For this study,eleven conditioning factors(aspect,altitude,curvature,slope,Stream Transport Index(STI),Topographic Wetness Index(TWI),soil,geology,river density,rainfall,land-use)and 134 wells yield data was used to create training(70%)and testing(30%)datasets for the development and validation of the models.Several statistical indices were used namely Positive Predictive Value(PPV),Negative Predictive Value(NPV),Sensitivity(SST),Specificity(SPF),Accuracy(ACC),Kappa,and Receiver Operating Characteristics(ROC)curve to validate and compare performance of models.Results show that performance of all the models is good to very good(AUC:0.75 to 0.829)but the ABLWL model with AUC=0.89 is the best.All the models applied in this study can support decision-makers to streamline the management of the groundwater and to develop economy not only of specific territories but also in other regions across the world with minor changes of the input parameters.
文摘Black pepper varieties, namely “Vinh Linh”, “Lada”, “An Do” and “Loc Ninh” were planted in three different ecological regions: Dak Lak, Gia Lai and Dong Nai in order to compare the growth ability, productivity, and quality of peppercorn. The experiments were designed in the Randomized Complete Block Design (RCBD) with four replications. The results of study have been indicated that “Vinh Linh” and “Lada” both varieties performed better crucial parameters of growth, productivity and yield, after 36 months planted. Although having greater growth parameter in the location of Dong Nai province, four varieties showed lower yield than other regions. By contrast, the four pepper types achieved the highest yield in Gia Lai, followed by Dak Lak. With respect to peppercorn quality, “Vinh Linh”, “Loc Ninh” and “Lada” achieved requirements of Vietnamese Standard (TCVN 7036:2008) including bulk density: 535.69 - 612.72 g/l;piperine: 4.06 - 4.31 g/100g and volatile oil at 2.72 - 3.16 ml/100g. In contrast, “An Do” variety presented the poorest level of piperine (3.78 g/100g), and unachieved requirements.
基金funded by Le Quy Don Technical University Research Found (Grant No.2023QHT.03)。
文摘The main goal of this study is to use higher-order isogeometric analysis(IGA)to study the dynamic response of sandwich shells with an auxetic honeycomb core and two different functionally graded materials(FGM)skin layers(namely honeycomb-FGS shells)subjected to dynamic loading.Touratier's non-polynomial higher-order shear deformation theory(HSDT)is used due to its simplicity and performance.The governing equation is derived from Hamilton's principle.After verifying the present approach,the effect of input parameters on the dynamic response of honeycomb-FGS shells is carried out in detail.
文摘Heavy metals may induce bacterial antibiotic resistance and affect their growth in the ecosystem.In this study,we aim to determine bacterial growth and antibiotic resistance in the pressure of heavy metals.Observed the changing morphology by gram staining was checked for bacterial toleration with heavy metal,developing of the colony form unit(CFU)was analysed bacterial kinetic growths and their biofilm formation.The disk diffusion test was used to perform bacterial susceptibility profiles with Ceftazidime(30μg),Ceftriaxone(30μg),Colistin sulfate(10μg),Meropenem or Imipenem(10μg),Ciprofloxacin(5μg)and Azithromycin(15μg)and the CLSI was applied for interpreting the data.The bacterial morphology remarkably changed from normal to short,round shape at a high concentration of heavy metals after 1 month.Their changing shape adapted to heavy metals by survival growing and resisted to Azithromycin,Ciprofloxacin,and Colistin without biofilm formation after 1 month,that was continued increasing after 2 months.The bacterial growth and antibiotic resistance were significant differences between provinces(P=0.01),type of bacterial species,and concentration of heavy metals.These results indicate that heavy metals are a crucial factor-driven for enhancing bacterial adaptation in pollution water resources and inducing their antimicrobial resistance in the aquatic environment.
文摘This paper uses isogeometric analysis(IGA)based on higher-order shear deformation theory(HSDT)to study the dynamic response of bio-inspired helicoid laminated composite(B-iHLC)plates resting on Pasternak foundation(PF)excited by explosive loading.IGA takes advantage of non-uniform rational Bspline(NURBS)basic functions to exactly represent the structure geometry models and the attainment of higher-order approximation conditions.This method also ensures a C1 continuous function in the analysis of transverse shear deformation via HSDT.Furthermore,IGA eliminates the requirement for correction factors and delivers accurate results.Pasternak foundation with two stiffness parameters:springer stiffness(k_(1))and shear stiffness(k_(2)).The derivation of the governing equations is based on Hamilton's principle.The proposed method is validated through numerical examples.A comprehensive analysis of the impact of geometrical parameters,material properties,boundary conditions(BCs),and foundation stiffness on dynamic response of B-i HLC plates is carried out.
