5,078 results on '"Hai Nguyen"'
Search Results
2. First-aid training for primary Healthcare providers on a remote Island: a mixed-methods study
- Author
-
Ninh Do Thi, Giang Hoang Thi, Yoonjung Lee, Khue Pham Minh, Hai Nguyen Thanh, Jwa-Seop Shin, and Tuyen Luong Xuan
- Subjects
Mixed-methods ,First aid ,Continuous training ,Primary healthcare provider ,Vietnam ,Special aspects of education ,LC8-6691 ,Medicine - Abstract
Abstract Background Ensuring ongoing first-aid training for primary healthcare providers (PHPs) is one of the critical strategies for providing quality health services and contributing to achieving universal health coverage. However, PHPs have received insufficient attention in terms of training and capacity building, especially in the remote areas of low-to-middle-income countries. This study evaluated the effectiveness of a first-aid training program for PHPs on a Vietnamese island and explored their perspectives and experiences regarding first-aid implementation. Methods A mixed-methods study was conducted among 39 PHPs working in community healthcare centers. The quantitative method utilized a quasi-experimental design to evaluate participants’ first-aid knowledge at three time points: pre-training, immediately post-training, and three months post-training. Sixteen of the PHPs participated in subsequent semi-structured focus group interviews using the qualitative method. Quantitative data were analyzed using repeated measures analysis of variance (ANOVA), while qualitative data were subjected to thematic analysis. Results The quantitative results showed a significant improvement in both the overall mean first-aid knowledge scores and the subdimensions of the first-aid knowledge scores among healthcare providers post-training. There was a statistically significant difference between the baseline and immediate posttest and follow-up knowledge scores (p 0.05). Three main themes emerged from the focus group discussions: perception of first-aid in remote areas, facilitators and barriers. Participants identified barriers, including infrastructure limitations, shortage of the primary healthcare workforce, inadequate competencies, and insufficient resources. Conversely, receiving considerable support from colleagues and the benefits of communication technologies in implementing first aid were mentioned as facilitators. The training bolstered the participants’ confidence in their first-aid responses, and there was a desire for continued education. Conclusions Implementing periodic first-aid refresher training for PHPs in a nationwide resource-limited setting can contribute significantly to achieving universal health coverage goals. This approach potentially enhances the preparedness of healthcare providers in these areas to deliver timely and effective first aid during emergencies, which may lead to more consistent primary healthcare services despite various challenges.
- Published
- 2024
- Full Text
- View/download PDF
3. Recruitment and retention of pediatric participants for pandemic preparedness research: Experience from the PREMISE EV-D68 Pilot Study
- Author
-
Hai Nguyen-Tran, Alicen B. Spaulding, Kevin Messacar, Matthew R. Vogt, Perdita Permaul, Daniel C. Douek, Abe Mittelman, Careese Thompson, Sandy Grubbs, Christine Magana, and Michelle L. Hernandez
- Subjects
Pediatric ,Cohort study ,Recruitment ,Retention ,Pandemic preparedness ,Medicine (General) ,R5-920 - Abstract
Recruitment and retention are challenges for prospective pediatric cohort studies, particularly those involving serial venipunctures. We investigated factors underlying enrollment and retention in the Pandemic Response Repository through Microbial and Immune Surveillance and Epidemiology (PREMISE) Enterovirus D68 (EV-D68) Pilot Study, a multicenter prospective longitudinal cohort study assessing the utility of immunologic surveillance for pandemic preparedness. This study enrolls children ≤10 years for two blood draws, pre- and post-EV-D68 season, separated by 6–18 months. Overall, 174 children were enrolled in Cohort 1 of the study and 120 (69 %) of children completed the study, with follow-up blood samples obtained from 101 (58 %) of participants. Families were primarily motivated to participate by a desire to help other children, advance science, and better prepare for the next pandemic. Adding research blood draws to clinically indicated blood draws improved enrollment, and multiple study touch points facilitated retention. These findings can be applied to improve recruitment and retention in future pandemic preparedness efforts and longitudinal pediatric cohort studies.
- Published
- 2024
- Full Text
- View/download PDF
4. On inverse source term for heat equation with memory term
- Author
-
Duc Nam Bui, Hai Nguyen Minh, Hoan Luu Vu Cam, and Long Le Dinh
- Subjects
inverse source problem ,parabolic equation ,memory term ,regularization method ,error estimate ,35k99 ,47j06 ,47h10 ,35k05 ,Mathematics ,QA1-939 - Abstract
In this article, we first study the inverse source problem for parabolic with memory term. We show that our problem is ill-posed in the sense of Hadamard. Then, we construct the convergence result when the parameter tends to zero. We also investigate the regularized solution using the Fourier truncation method. The error estimate between the regularized solution and the exact solution is obtained.
- Published
- 2024
- Full Text
- View/download PDF
5. Symptoms, Mental Health, and Quality of Life Among Patients After COVID-19 Infection: A Cross-sectional Study in Vietnam
- Author
-
Hai Nguyen Thanh, Duc Cap Minh, Hien Hoang Thu, and Duc Nguyen Quang
- Subjects
mental health ,quality of life ,covid-19 ,vietnam ,Medicine ,Public aspects of medicine ,RA1-1270 - Abstract
Objectives: This study was conducted to characterize the symptoms, mental health, quality of life (QoL), and associated factors following the coronavirus disease 2019 (COVID-19) infection. Methods: This cross-sectional study included 394 participants previously infected with COVID-19 in Ho Chi Minh City, Vietnam. Mental health was assessed using the 21-item Depression, Anxiety, and Stress Scale (DASS-21). Participants self-reported health-related QoL was measured with the EuroQol 5-Dimension 5-Level (EQ-5D-5L) scale. Results: Among the participants, 76.4% reported experiencing at least one symptom following COVID-19 infection. The most common symptoms were fatigue (42.1%), cognitive dysfunction (42.9%), and hair loss (27.9%). According to the DASS-21 results, the proportions of depression, anxiety, and stress were 28.7%, 26.4%, and 20.6%, respectively. The mean scores on the EQ-5D-5L and the EuroQol Visual Analog Scale were 0.94±0.11 and 84.20±13.11, respectively. Regarding QoL issues, the highest proportion of participants (32.7%) reported experiencing anxiety or depression, followed by pain or discomfort (25.4%). Multivariable logistic regression analysis revealed that factors associated with the presence of symptoms following COVID-19 infection included female (odds ratio [OR], 2.84; 95% confidence interval [CI], 1.65 to 4.91) and having QoL issues (OR, 3.25; 95% CI, 1.71 to 6.19). Conclusions: The study investigated the prevalence rates of various symptoms following COVID-19 infection. These findings underscore the need to prioritize comprehensive care for individuals recovering from COVID-19 and to implement strategies to mitigate the long-term impact of the disease on mental health and QoL.
- Published
- 2024
- Full Text
- View/download PDF
6. Evaluating left atrial function changes by speckle tracking echocardiography in type 2 diabetes patients in Central Vietnam: a cross-sectional comparative study
- Author
-
Hai Nguyen Ngoc Dang, Thang Viet Luong, and Toan Thanh Tran
- Subjects
Diabetes mellitus ,Left atrial function ,Speckle tracking echocardiography ,Central Vietnam ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Abstract Background Type 2 diabetes mellitus (T2DM) is a metabolic disorder that detrimentally affects multiple systems in the body, with a particular emphasis on the vascular and nervous systems. Despite its significant impact, limited studies have explored the influence of this condition on the left atrial (LA) function. To address this gap, our study utilized speckle tracking echocardiography (STE) to assess LA function in patients with T2DM in Central Vietnam. Results The cross-sectional comparative study enrolled 134 subjects involving 66 patients with T2DM and 68 healthy individuals meeting the selection and exclusion criteria of the study. In our study, healthy individuals demonstrated higher values for LA reservoir strain (LASr), LA conduit strain (LAScd), and LA contractile strain (LASct), measuring 38.75% ± 5.43%, 19.58% ± 5.91%, and 19.16% ± 4.98%, respectively. In contrast, the T2DM group exhibited lower values for LASr, LAScd, and LASct, which measured 31.2% ± 4.56%, 14.77% ± 6.3%, and 16.36% ± 4.82%, respectively (p
- Published
- 2024
- Full Text
- View/download PDF
7. Multimodal Surveillance Model for Enterovirus D68 Respiratory Disease and Acute Flaccid Myelitis among Children in Colorado, USA, 2022
- Author
-
Kevin Messacar, Shannon Matzinger, Kevin Berg, Kirsten Weisbeck, Molly Butler, Nicholas Pysnack, Hai Nguyen-Tran, Emily Spence Davizon, Laura Bankers, Sarah A. Jung, Meghan Birkholz, Allison Wheeler, and Samuel R. Dominguez
- Subjects
Enterovirus D68 ,EV-D68 ,surveillance ,disease outbreak ,viruses ,Colorado ,Medicine ,Infectious and parasitic diseases ,RC109-216 - Abstract
Surveillance for emerging pathogens is critical for developing early warning systems to guide preparedness efforts for future outbreaks of associated disease. To better define the epidemiology and burden of associated respiratory disease and acute flaccid myelitis (AFM), as well as to provide actionable data for public health interventions, we developed a multimodal surveillance program in Colorado, USA, for enterovirus D68 (EV-D68). Timely local, state, and national public health outreach was possible because prospective syndromic surveillance for AFM and asthma-like respiratory illness, prospective clinical laboratory surveillance for EV-D68 among children hospitalized with respiratory illness, and retrospective wastewater surveillance led to early detection of the 2022 outbreak of EV-D68 among Colorado children. The lessons learned from developing the individual layers of this multimodal surveillance program and how they complemented and informed the other layers of surveillance for EV-D68 and AFM could be applied to other emerging pathogens and their associated diseases.
- Published
- 2024
- Full Text
- View/download PDF
8. Kernel-Based Dimension Reduction Method for Time Series Nowcasting
- Author
-
Thanh Do Van and Hai Nguyen Minh
- Subjects
Big data ,dimension reduction ,dynamic factor model ,Kernel tricks ,nowcasting ,principal component analysis ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Nowcasts are closely related to big data. Currently, the most popular nowcast model-building approach is to use the factor bridge equation (BE) model or factor mixed data sampling (MIDAS) model, where the factors are extracted from large datasets using the principal component analysis (PCA) method. However, the PCA method only suits datasets approximating a hyperplane, while real-world datasets are sometimes unsuitable. This study proposes a kernel-based dimension reduction method. It is a natural extension of the PCA method and is called KTPCA. The KTPCA method can reduce the dimensionality of datasets without approximating a hyperplane. The dimension reduction performance of the iterative KTPCA method was superior to that of the PCA, Sparse PCA (SPCA), Randomized SPCA (RSPCA), and Robust SPCA (ROBSPCA) methods. In addition, the PCA and SPCA methods are competitive regarding dimension reduction performance. This study also proposes a nowcasting procedure using the iterative KTPCA method. This procedure can be applied to build nowcast models and update the forecasts of a target variable at a low frequency under real-time data flow of the original variables at a higher frequency.
- Published
- 2024
- Full Text
- View/download PDF
9. The correlation between liver fibrosis and the 10‐year estimated risk of cardiovascular disease in adults with metabolic‐associated fatty liver disease: A cross‐sectional study in Vietnam
- Author
-
Hai Nguyen Ngoc Dang, Thang Viet Luong, Toan Thanh Tran, and Tien Anh Hoang
- Subjects
cardiovascular risk ,FIB‐4 ,liver fibrosis ,metabolic‐associated fatty liver disease ,SCORE2 ,SCORE2‐OP ,Medicine - Abstract
Abstract Background and Aims Metabolic‐associated fatty liver disease (MAFLD) emerged as a novel term replacing nonalcoholic fatty liver disease (NAFLD) in 2020. While most MAFLD patients are asymptomatic, long‐term hepatic fat accumulation may lead to liver fibrosis and cardiovascular disease (CVD). Nevertheless, the relationship between MAFLD and cardiovascular (CV) risk factors remains unclear. This study aimed to assess the 10‐year estimated CVD risk in individuals diagnosed with MAFLD. Methods Between January 2022 and August 2023, this cross‐sectional study enrolled 139 MAFLD patients. We employed the systematic coronary risk evaluation 2 (SCORE2) and the systematic coronary risk evaluation 2–older persons (SCORE2‐OP) scoring systems to evaluate and categorize the 10‐year CV risk. Liver fibrosis was assessed using biochemical parameters (FIB‐4, AST/ALT, and APRI), and their correlation with CV risk was examined. Results Most MAFLD patients were categorized as having high or very high CV risk based on the SCORE2 and SCORE2‐OP. Liver fibrosis, measured by the FIB‐4 score, significantly differed among the various CV risk groups. Moreover, FIB‐4 correlated positively with SCORE2 and SCORE2‐OP (r = 0.588, p < 0.001), indicating its substantial predictive ability for identifying individuals at very high CV risk (AUC = 0.765, 95% CI: 0.686–0.845, p < 0.001). A FIB‐4 score of 1.275 demonstrated 81% sensitivity and 64% specificity in predicting very high CV risk among MAFLD patients. Conclusion Patients with MAFLD predominantly face high or very high CV risks, with elevated liver fibrosis associated with increased 10‐year estimated CVD risk. The FIB‐4 score exhibits promising predictive value for identifying MAFLD patients at very high risk of CV disease.
- Published
- 2024
- Full Text
- View/download PDF
10. Evaluation of the relationship between left atrial stiffness, left ventricular stiffness, and left atrioventricular coupling index in type 2 diabetes patients: a speckle tracking echocardiography study
- Author
-
Hai Nguyen Ngoc Dang, Thang Viet Luong, and Binh Anh Ho
- Subjects
speckle tracking echocardiography ,left atrial stiffness ,left ventricular stiffness ,left atrioventricular coupling index ,diabetes mellitus ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
BackgroundCardiovascular complications are a leading cause of mortality and disability in individuals with diabetes mellitus (DM). Moreover, DM can directly impact the structure and function of cardiac muscle. We conducted a study to evaluate cardiac stiffness in DM patients in both the left atrium (LA) and left ventricle (LV), as well as to assess the impact of DM on the synchronization of the LA and LV, particularly within the Vietnamese population, utilizing speckle tracking echocardiography (STE).MethodsWe studied 111 research subjects divided into two groups comprising 52 patients with DM and 59 healthy individuals. All the subjects provided relevant clinical information, and echocardiography was performed to assess the indices of LA stiffness, LV stiffness, and left atrioventricular coupling index (LACI).ResultsOur study indicated that DM patients exhibited greater LA and LV stiffness than control patients. The LACI (%) in the DM group was also greater than that in the control group (17.12% ± 6.72% vs. 12.28% ± 3.96%, respectively; p
- Published
- 2024
- Full Text
- View/download PDF
11. Duration of Enterovirus D68 RNA Shedding in the Upper Respiratory Tract and Transmission among Household Contacts, Colorado, USA
- Author
-
Hai Nguyen-Tran, Careese Thompson, Molly Butler, Kristen R. Miller, Laura Pyle, Sarah Jung, Shannon Rogers, Terry Fei Fan Ng, Janell Routh, Samuel R. Dominguez, and Kevin Messacar
- Subjects
Enterovirus D68 ,EV-D68 ,acute flaccid myelitis ,viruses ,respiratory infections ,virus shedding ,Medicine ,Infectious and parasitic diseases ,RC109-216 - Abstract
Enterovirus D68 (EV-D68) causes cyclical outbreaks of respiratory disease and acute flaccid myelitis. EV-D68 is primarily transmitted through the respiratory route, but the duration of shedding in the respiratory tract is unknown. We prospectively enrolled 9 hospitalized children with EV-D68 respiratory infection and 16 household contacts to determine EV-D68 RNA shedding dynamics in the upper respiratory tract through serial midturbinate specimen collections and daily symptom diaries. Five (31.3%) household contacts, including 3 adults, were EV-D68–positive. The median duration of EV-D68 RNA shedding in the upper respiratory tract was 12 (range 7–15) days from symptom onset. The most common symptoms were nasal congestion (100%), cough (92.9%), difficulty breathing (78.6%), and wheezing (57.1%). The median illness duration was 20 (range 11–24) days. Understanding the duration of RNA shedding can inform the expected rate and timing of EV-D68 detection in associated acute flaccid myelitis cases and help guide public health measures.
- Published
- 2023
- Full Text
- View/download PDF
12. Detecting Reinforced Concrete Rebars Using Ground Penetrating Radars
- Author
-
Wael Zatar, Hien Nghiem, and Hai Nguyen
- Subjects
nondestructive evaluation ,ground-penetrating radar ,rebar depth ,rebar diameter ,reinforced-concrete structures ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
A new algorithm is developed to automatically detect rebar locations and diameters of reinforced concrete structures using the ground penetrating radar technique. The study uses two-way travel time and biquadratic equations to formulate electromagnetic wave speed in reinforced concrete structures where hyperbolic signatures are approximated. Leveraging an established algorithm, a computer code has been developed to offer automated analysis of ground-penetrating radar data obtained from survey grids. Four reinforced concrete slabs were designed, fabricated, and tested to validate the developed evaluation approach. The proposed methodology demonstrates outstanding signal processing proficiency and reliably and effectively identifies rebar information.
- Published
- 2024
- Full Text
- View/download PDF
13. Mass production of entomopathogenic fungi Purpureocillium lilacinum PL1 as a biopesticide for the management of Amrasca devastans (Hemiptera: Cicadellidae) in okra plantation
- Author
-
Hai Nguyen Thi, Quynh Nhu Nguyen, Nhu Quynh Dang Thi, Ngoc Lam Nguyen, and Anh Duy Do
- Subjects
Amrasca devastans ,Biopesticides ,Purpureocillium lilacinum ,Fermentation ,Pest management ,Agriculture - Abstract
Abstract Background Effective management strategies are crucial in minimizing the adverse consequences associated with the leafhopper, Amrasca devastans (Dist.) (Hemiptera: Cicadellidae). Economic limitations to entomopathogenic fungi production present a substantial challenge, particularly in developing countries. This study aimed to investigate a cost-effective solid-state fermentation (SSF) for large-scale production of Purpureocillium lilacinum PL1 conidia to manage A. devastans infestations in okra cultivation. Results Rice and maize were demonstrated as highly suitable substrates for producing conidia densities of over 2 × 1010 conidia g−1. Furthermore, the influence of agricultural phytosanitary agents on the growth rates of P. lilacinum PL1 was evaluated. Certain pesticides were ineffective on the expansion of P. lilacinum PL1 colonies, while fungicides exhibited complete inhibition. The laboratory investigation revealed that 1 × 107 conidia ml−1 of P. lilacinum PL1 exhibited a success rate of 88.66% in decreasing the population of A. devastans nymphs in vitro. Furthermore, field investigations carried out in okra plantations demonstrated that the utilization of P. lilacinum PL1 at the concentration of 1 × 107 conidia ml−1 of resulted in a significant reduction of the pest nymph population by 72.87% subsequent to the 2 applications. Conclusion In conclusion, the cost-effective mass production of P. lilacinum PL1 conidia through SSF presents a promising solution for managing A. devastans infestations in okra farming, particularly in economically challenged regions.
- Published
- 2023
- Full Text
- View/download PDF
14. Investigation of phase difference and separation distance effects in the design of a dual flapping hydrofoil turbine
- Author
-
Dasom Jeong, Hai Nguyen Le Dang, and Jin Hwan Ko
- Subjects
CFD ,flapping hydrofoil turbine ,parametric analysis ,power efficiency ,power fluctuation ,Technology ,Science - Abstract
Abstract In this study, a parametric analysis was conducted for the design of a suggested dual flapping hydrofoil turbine. A Navier–Stokes‐based computational fluid dynamics code was utilized for the analysis while varying the pitch angle, reduced frequency, separation distance, and phase difference. The smallest pitch angle of 60° and the reduced frequency of 0.1 among the given ranges of the parameters were fixed for the first parametric analysis. After an assessment, the 90° front‐lead with the longest distance of 6c and the 90° rear‐lead with the shortest distance of 2c were chosen for further parametric analysis based on a suggested performance indicator and a margin for improvement. It was derived from a subsequent parametric analysis that a 70° pitch angle, 0.12 reduced frequency, and a 4c distance for the 90° front‐lead was the final optimum with 59.48% efficiency and 55.44% fluctuation according to the performance indicator as well as the system length and power balance of dual hydrofoils.
- Published
- 2023
- Full Text
- View/download PDF
15. Urine lipoarabinomannan concentrations among HIV-negative adults with pulmonary or extrapulmonary tuberculosis disease in Vietnam.
- Author
-
Nguyen B Hoa, Mark Fajans, Hung Nguyen Van, Bao Vu Ngoc, Nhung Nguyen Viet, Hoa Nguyen Thi, Lien Tran Thi Huong, Dung Tran Minh, Cuong Nguyen Kim, Trinh Ha Thi Tuyet, Tri Nguyen Huu, Diep Bui Ngoc, Hai Nguyen Viet, An Tran Khanh, Lorraine Lillis, Marcos Perez, Katherine K Thomas, Roger B Peck, Jason L Cantera, Eileen Murphy, Olivia R Halas, Helen L Storey, Abraham Pinter, Morten Ruhwald, Paul K Drain, and David S Boyle
- Subjects
Public aspects of medicine ,RA1-1270 - Abstract
Lipoarabinomannan (LAM) is a promising target biomarker for diagnosing subclinical and clinical tuberculosis (TB). Urine LAM (uLAM) testing using rapid diagnostic tests (RDTs) has been approved for people living with HIV (PLWH), however there is limited data regarding uLAM levels in HIV-negative (HIV-ve) adults with clinical TB. We conducted a clinical study of adults presenting with clinical TB-related symptoms at the National Lung Hospital in Hanoi, Vietnam. The uLAM concentrations were measured using electrochemiluminescent (ECL) immunoassays and compared to a microbiological reference standard (MRS) using GeneXpert Ultra and TB culture testing. Estimated uLAM concentrations above plate specific calculated limit of detection (LOD) were considered uLAM positive. Additional microbiological testing was conducted for possible extrapulmonary TB (EPTB). Among 745 participants enrolled, 335 (44.9%) participants with presumptive pulmonary TB (PTB) and 6 (11.3%) participants with presumptive EPTB had confirmed TB disease. Overall, the S/A antibody pair had a sensitivity of 39% (95% Confidence Interval [CI] 0.33, 0.44) and a specificity of 97% (95% CI 0.96, 0.99) compared to the MRS. The F/A antibody pair had a sensitivity of 41% (95% CI 0.35, 0.47) and a specificity of 79% (95% CI 0.75, 0.84). S/A provided greater discriminatory ability compared to F/A for both individuals with presumptive PTB (AUROC: 0.74 vs 0.63, p
- Published
- 2024
- Full Text
- View/download PDF
16. Insecticidal activity of isolated Purpureocillium lilacinum PL1 against whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) on cassava plantations in southern Viet Nam
- Author
-
Hai Nguyen Thi, Kim Yen Phung Le, Ngoc Duc Thai Thien, Thanh Diem Nguyen, and Anh Duy Do
- Subjects
Purpureocillium lilacinum ,Bemisia tabaci ,Entomopathogenic fungi ,Chitinase ,Protease ,Agriculture - Abstract
Abstract Background Whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a plant-damaging insect in tropical and subtropical regions that causes agricultural damage worldwide, including in Viet Nam. The abuse of pesticides derived from chemicals has resulted in the evolution of insect-resistant strains, polluting the environment and threatening human health. Using entomopathogenic fungi (EPF) for biological control is an alternative strategy in integrated pest management. Hence, an attempt was conducted to isolate, characterize and evaluate the efficacy of EPF, Purpureocillium lilacinum against whitefly B. tabaci under laboratory and field conditions. Results Purpureocillium lilacinum PL1 (PL1) was isolated from the whitefly B. tabaci cadavers and subsequently identified using morphological study and internal transcribed spacer sequencing. Purpureocillium lilacinum PL1 had effectively grown and sporulated at temperatures ranging from 25 to 35 °C and throughout a broad pH range, which is particularly advantageous against the harsh tropical monsoon climate. Bioassay study indicated that 1 × 107 conidia/ml of P. lilacinum PL1 had a high lethality against the whitefly B. tabaci nymphs in vitro with efficiency was 88.24% after 7 days of treatment. The median lethal concentration (LC50) of P. lilacinum PL1 to B. tabaci after 7 days of treatment was 1.24 × 105 conidia/ml. In field conditions, 1 × 107 conidia/ml of P. lilacinum PL1 lowered the population of B. tabaci nymphs with efficacy was 78.86% after 2 batches, 7 days after treatments. Conclusion The findings indicated that P. lilacinum PL1 was effective in the biological control of B. tabaci nymphs, which could be a potential alternative to chemical pesticides for pest management.
- Published
- 2023
- Full Text
- View/download PDF
17. Superiority of left heart deformation in early anthracycline-related cardiac dysfunction detection
- Author
-
Nhat Giang M, Hai Nguyen H, Duc Tan Vo, Tri Ho Huynh Quang, Duc Thi Hong Phan, and Ngoc-Hoa Chau
- Subjects
Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Objective This study aimed to assess the incidence of early cancer therapy-related cardiac dysfunction (CTRCD) and the characteristics of left and right heart deformations during anthracycline chemotherapy.Methods We prospectively enrolled a cohort of 351 chemotherapy-naïve women with breast cancer and cardiovascular risk factors who were scheduled to receive anthracycline. The left ventricular ejection fraction (LVEF), left ventricular global longitudinal strain (LV-GLS) and right ventricular and left atrial longitudinal strains were evaluated using echocardiography at baseline, before every subsequent cycles and at 3 weeks after the final anthracycline dose. CTRCD was defined as a new LVEF reduction by ≥10 percentage points to an LVEF15% from the baseline value.Results Eighteen (5.1%) patients had evidence of asymptomatic CTRCD during anthracycline treatment, and 50% developed CTRCD before completing the chemotherapy regimen. In the CTRCD group, while LV-GLS decrease significantly after the first dose of anthracycline, the reduction of right ventricular free-wall longitudinal strain and left atrial reservoir strain were observed after the second dose. Other strain indices could not be used to identify early CTRCD.Conclusions Cardiotoxicity appeared soon after the initiation of anthracycline chemotherapy. Among the left-heart and right-heart mechanics, LV-GLS remains the best deformation indicator for detecting early CTRCD.
- Published
- 2023
- Full Text
- View/download PDF
18. Strongyloides stercoralis infection reduces Fusicatenibacter and Anaerostipes in the gut and increases bacterial amino-acid metabolism in early-stage chronic kidney disease
- Author
-
Na T.D. Tran, Apisit Chaidee, Achirawit Surapinit, Manachai Yingklang, Sitiruk Roytrakul, Sawanya Charoenlappanit, Porntip Pinlaor, Nuttanan Hongsrichan, Hai Nguyen Thi, Sirirat Anutrakulchai, Ubon Cha'on, and Somchai Pinlaor
- Subjects
Strongyloides stercoralis ,Chronic kidney disease (CKD) ,Early-stage CKD ,high-throughput sequencing ,Metaproteomics ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Understanding gut bacterial composition and proteome changes in patients with early-stage chronic kidney disease (CKD) could lead to better methods of controlling the disease progression. Here, we investigated the gut microbiome and microbial functions in patients with S. stercoralis infection (strongyloidiasis) and early-stage CKD. Thirty-five patients with early stages (1–3) of CKD were placed in two groups matched for population characteristics and biochemical parameters, 12 patients with strongyloidiasis in one group and 23 uninfected patients in the other. From every individual, a sample of their feces was obtained and processed for 16S rRNA sequencing and metaproteomic analysis using tandem liquid chromatography-mass spectrometry (LC-MS/MS). Strongyloides stercoralis infection per se did not significantly alter gut microbial diversity. However, certain genera (Bacteroides, Faecalibacterium, Fusicatenibacter, Sarcina, and Anaerostipes) were significantly more abundant in infection-free CKD patients than in infected individuals. The genera Peptoclostridium and Catenibacterium were enriched in infected patients. Among the significantly altered genera, Fusicatenibacter and Anaerostipes were the most correlated with renal parameters. The relative abundance of members of the genus Fusicatenibacter was moderately positively correlated with estimated glomerular filtration rate (eGFR) (r = 0.335, p = 0.049) and negatively with serum creatinine (r = −0.35, p = 0.039). Anaerostipes, on the other hand, showed a near-significant positive correlation with eGFR (r = 0.296, p = 0.084). Individuals with S. stercoralis infection had higher levels of bacterial proteins involved in amino-acid metabolism. Analysis using STITCH predicted that bacterial amino-acid metabolism may also be involved in the production of colon-derived uremic toxin (indole), a toxic substance known to promote CKD. Strongyloides stercoralis infection is, therefore, associated with reduced abundance of Fusicatenibacter and Anaerostipes (two genera possibly beneficial for kidney function) and with increased bacterial amino-acid metabolism in the early-stages of CKD, potentially producing uremic toxin. This study provides useful information for prevention of progression of CKD beyond the early stages.
- Published
- 2023
- Full Text
- View/download PDF
19. Modeling N2O emissions with remotely sensed variables using machine learning
- Author
-
Paul R Adler, Hai Nguyen, Benjamin M Rau, and Curtis J Dell
- Subjects
bioenergy ,greenhouse gas emissions ,life cycle assessment ,Miscanthus ,switchgrass ,nitrous oxide ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
Nitrous oxide is the largest source of greenhouse gas emissions from crop production. There is significant interest in targeting marginal lands for growing biomass crops, however little information is available on how this will affect N _2 O emissions from these crops. Furthermore, to characterize N _2 O emission at the farm level to quantify mitigation using measurements is time intensive, costly, and impractical. We selected a highly diverse watershed varying in soil texture and topography to compare two approaches for modeling soil N _2 O emissions using machine learning, intensive measurements of soil environment and climate variables, with the other only using remotely sensed variables. We confirmed that soil nitrogen was the most important variable followed by soil environment as influence by soil characteristic, topography, and climate. We also found that the machine learning model built on remotely sensed variables performed as well as when direct site level measurements were available. This finding supports the potential of using remotely sensed data to build machine learning models to characterize soil N _2 O emissions without the need for intensive soil measurements for entity level assessments.
- Published
- 2024
- Full Text
- View/download PDF
20. Amplification Ratio of a Recycled Plastics-Compliant Mechanism Flexure Hinge
- Author
-
Tran Minh The Uyen, Pham Son Minh, Van-Thuc Nguyen, Thanh Trung Do, Hai Nguyen Le Dang, and Van Thanh Tien Nguyen
- Subjects
ABS ,amplification ratio ,recycle ratio ,HDPE ,PP ,LDPE/TPU ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This research focuses on the fabrication of plastic flexure hinges from diverse plastics such as ABS, PP, HDPE, and LDPE. To enhance hinge efficiency, the recycling ratios are also investigated. The amplification ratio of different recycle ratios and plastic types are measured. The results show that the input and output displacements of all PP, ABS, and HDPE hinges are linear. The presence of recycled plastics has no impact on this basis. The pure PP, ABS, and HDPE flexure hinges achieve the highest amplification ratios of 5.728, 8.249, and 5.668. The addition of recycled plastics reduces the amplification ratio. This decrease in the amplification ratio, however, is small. At a 25% recycle ratio, the PP, ABS, and HDPE flexure hinges have 12%, 13.3%, and 21.7% lower amplification ratios than the pure plastic hinges. Furthermore, the utilization of recycled plastics may lessen the need for new plastic made from raw materials. With the PP flexure hinge, a maximum input value of 157 µm could result in an output value of 886 µm. At a maximum input value of 115 µm, the ABS flexure hinge could achieve an output value of 833 µm. Finally, a maximum input value of 175 µm might result in an output value of 857 µm when using the HDPE flexure hinge. The average amplification ratio values for all recycling ratios for PP, ABS, and HDPE flexure hinges are, respectively, 5.35, 7.60, and 5.02. The ABS flexure hinge frequently outperforms the PP and HDPE flexure hinge in terms of amplification ratios. Among these plastics, HDPE flexure hinges have the lowest amplification ratio. In general, increasing the thermoplastic polyurethane (TPU) content of the LDPE/TPU blend increases the amplification ratio. The cause could be the TPU’s high compatibility with the LDPE polymer. The LDPE/TPU blend hinge offers a broader range of the amplification ratio of 2.85–10.504 than the PP, ABS, and HDPE flexure hinges. It is interesting that changing the blend percentage has a much greater impact on the amplification ratio than changing the recycling ratio. The findings broaden the range of applications for plastic flexure hinges by identifying optimal plastic types. The impact of the hinge shape on the performance of the injected plastic flexure hinge might be studied in further research.
- Published
- 2023
- Full Text
- View/download PDF
21. Lessons from 20 years of medical cannabis use in Canada.
- Author
-
Minsup Shim, Hai Nguyen, and Paul Grootendorst
- Subjects
Medicine ,Science - Abstract
BackgroundCanada was one of the first countries to regulate the medical use of cannabis. However, literature on Canada's medical cannabis program is limited.MethodsWe use administrative data from the medical cannabis program, and licensed cannabis vendor catalog data to describe a) the participation of patients, physicians, and cannabis vendors in the program from its inception in 1999 to 2021, and b) trends in medical cannabis consumption, prices and potency. We also use national surveys conducted over the last several decades to estimate trends in regular cannabis use (medical or otherwise) and how it changed during the medical cannabis access regimes.ResultsIn 2001, the Canadian government granted access to those with physician-documented evidence of a severe health problem that could not be managed using conventional therapies. Most patients accessed cannabis grown under a personal production license. By 2013, authorized daily cannabis dosages were very high. In 2014, the government, concerned over illegal diversion, required that cannabis be purchased from a licensed commercial grower; personal production was banned. Physicians were given responsibility for authorizing patient access. To fill the regulatory void, the physician regulatory bodies in Canada imposed their own prescribing restrictions. After these changes, the number of physicians who were willing to support patient cannabis use markedly decline but the number of patients participating in the program sharply increased. Medical cannabis use varied by province-rates were generally lower in provinces with stricter regulations on physician cannabis prescribing. Most varieties of cannabis oil available for sale are now high in CBD and low in THC. Dry cannabis varieties, conversely, tend to be high in THC and low in CBD. Inflation adjusted prices of most varieties of medical cannabis have declined over time. We find that rates of daily cannabis use (medical or otherwise) increased markedly after the 2014 policy regime. The fraction of Canadians using cannabis daily increased again after the 2018 legalization of recreational cannabis; at the same time, participation in the medical access program declined.ConclusionThe implications for patient health outcomes of changes in the medical cannabis program and legalization of recreational use remains an important area for future research.
- Published
- 2023
- Full Text
- View/download PDF
22. Characterizing T cell responses to enzymatically modified beta cell neo-epitopes
- Author
-
Hai Nguyen, David Arribas-Layton, I-Ting Chow, Cate Speake, William W. Kwok, Martin J. Hessner, Carla J. Greenbaum, and Eddie A. James
- Subjects
T cell ,citrullinated autoantigens ,deamidated autoantigens ,Type 1 diabetes (T1D) ,at risk ,Immunologic diseases. Allergy ,RC581-607 - Abstract
IntroductionPrevious studies verify the formation of enzymatically post-translationally modified (PTM) self-peptides and their preferred recognition by T cells in subjects with type 1 diabetes (T1D). However, questions remain about the relative prevalence of T cells that recognize PTM self-peptides derived from different antigens, their functional phenotypes, and whether their presence correlates with a specific disease endotype.MethodsTo address this question, we identified a cohort of subjects with T1D who had diverse levels of residual beta cell function. Using previously developed HLA class II tetramer reagents, we enumerated T cells that recognize PTM GAD epitopes in the context of DRB1*04:01 or PTM IA2 epitopes in the context of DQB1*03:02 (DQ8).ResultsConsistent with prior studies, we observed higher overall frequencies and a greater proportion of memory T cells in subjects with T1D than in HLA matched controls. There were significantly higher numbers of GAD specific T cells than IA2 specific T cells in subjects with T1D. T cells specific for both groups of epitopes could be expanded from the peripheral blood of subjects with established T1D and at-risk subjects. Expanded neo-epitope specific T cells primarily produced interferon gamma in both groups, but a greater proportion of T cells were interferon gamma positive in subjects with T1D, including some poly-functional cells that also produced IL-4. Based on direct surface phenotyping, neo-epitope specific T cells exhibited diverse combinations of chemokine receptors. However, the largest proportion had markers associated with a Th1-like phenotype. Notably, DQ8 restricted responses to PTM IA2 were over-represented in subjects with lower residual beta cell function. Neo-epitope specific T cells were present in at-risk subjects, and those with multiple autoantibodies have higher interferon gamma to IL-4 ratios than those with single autoantibodies, suggesting a shift in polarization during progression.DiscussionThese results reinforce the relevance of PTM neo-epitopes in human disease and suggest that distinct responses to neo-antigens promote a more rapid decline in beta cell function.
- Published
- 2023
- Full Text
- View/download PDF
23. Unified Topographic and Atmospheric Correction for Remote Imaging Spectroscopy
- Author
-
Nimrod Carmon, Alexander Berk, Niklas Bohn, Philip Gregory Brodrick, Olga Kalashnikova, Hai Nguyen, David Ray Thompson, and Michael Turmon
- Subjects
atmospheric correction ,topographic correction ,radiative transfer modeling ,optimal estimation ,optimization ,surface reflectance ,Geophysics. Cosmic physics ,QC801-809 ,Meteorology. Climatology ,QC851-999 - Abstract
Models linking surface characteristics within incident solar radiation are inexorably dependent on the topography of the given region. To date, however, most operational surface reflectance retrievals treat this dependence by assuming a flat terrain, leading to significant deviations in the estimated reflectance. Here, we demonstrate that incorporating dynamic topography directly into the joint surface and atmospheric model during retrievals has several advantages. First, it allows for a more complete physical accounting of downwelling illumination, providing more accurate estimates of the absolute magnitude of reflectance. Second, it facilitates a superior resolution of the atmospheric state, most notably due to the confounding influence of atmospheric aerosols and unresolved topographic effects. Our methodology utilizes a practical, high-fidelity, model-driven approach to separate out diffuse and direct irradiation and account for topographic effects during the joint inversion of atmosphere and surface properties. We achieve this by enhancing the atmosphere/surface inversion to account for the radiative transfer effects of surface slope. We further demonstrate how uncertainties in topographic features can be quantified and leveraged within our formulation for a more realistic posterior uncertainty estimates. Our results demonstrate that the inclusion of topographic effects into the retrieval model reduces errors in the reflectance of an only moderately rugged terrain by more than 15%, and that a post hoc accounting of topography cannot achieve these same results.
- Published
- 2022
- Full Text
- View/download PDF
24. Triage Errors in Primary and Pre–Primary Care
- Author
-
Hai Nguyen, Andras Meczner, Krista Burslam-Dawe, and Benedict Hayhoe
- Subjects
Computer applications to medicine. Medical informatics ,R858-859.7 ,Public aspects of medicine ,RA1-1270 - Abstract
Triage errors are a major concern in health care due to resulting harmful delays in treatments or inappropriate allocation of resources. With the increasing popularity of digital symptom checkers in pre–primary care settings, and amid claims that artificial intelligence outperforms doctors, the accuracy of triage by digital symptom checkers is ever more scrutinized. This paper examines the context and challenges of triage in primary care, pre–primary care, and emergency care, as well as reviews existing evidence on the prevalence of triage errors in all three settings. Implications for development, research, and practice are highlighted, and recommendations are made on how digital symptom checkers should be best positioned.
- Published
- 2022
- Full Text
- View/download PDF
25. Characteristics of shear strength at the interface between two soil layers in ring shear apparatus
- Author
-
Duong NGUYEN THANH, Nu NGUYEN THI, Hai NGUYEN VAN, Lan NGUYEN CHAU, Tien PHAM VAN, and Motoyuki SUZUKI
- Subjects
discontinuous planes ,peak interface strength ,residual interface strength ,ring shear test ,Structural engineering (General) ,TA630-695 - Abstract
The slopes containing discontinuous planes such as bedding planes, rupture, or boundary between two soil layers are often prone to sliding. Thus, the characteristics of shear strength mobilized along the discontinuous planes should be examined. In this study, the shear strength at the interface between two different soil layers will be investigated based on ring shear test. The combined sample comprising of one kaolin layer and one kaolin + bentonite mixture layer was used to simulate the discontinuous planes between two soil layers. A number of ring shear tests were conducted on these samples at a normal stress of 98 kPa and shear rates from 0.02 to 20 mm/min using a multi-stage of shearing rates procedure. The research results indicate that the shear strength at the interface sharply increases to reach the peak value after a small shear displacement, then drops to the residual value. The residual interface strength tends to increase with increasing shear rates above 2 mm/min and the level of increase in residual interface strength depends on the contact surface. Furthermore, the effect of the order sample layer in combined samples can be ignored when determining the peak, the residual interface strengths as well as the rate effect on residual interface strength in the laboratory.
- Published
- 2020
26. On Modular Invariants of Truncated Polynomial Rings in low ranks
- Author
-
Ha, Le Minh, Hai, Nguyen Dang Ho, and Van Nghia, Nguyen
- Subjects
Mathematics - Rings and Algebras ,Mathematics - Algebraic Topology ,Mathematics - Combinatorics ,Primary 54C40, 14E20, Secondary 46E25, 20C20 - Abstract
We verify the conjectures due to Lewis, Reiner and Stanton about the Hilbert series of the invariant ring of the truncated polynomial ring for all parabolic subgroups up to rank $3$. This is done by constructing an explicit set of generators for each invariant ring in question. We also propose a conjecture concerning the action of the Steenrod algebra and the Dickson algebra on a certain naturally occurring filtration of the invariant ring under the general linear group., Comment: 22 pages
- Published
- 2024
27. LLMs Are Biased Towards Output Formats! Systematically Evaluating and Mitigating Output Format Bias of LLMs
- Author
-
Long, Do Xuan, Ngoc, Hai Nguyen, Sim, Tiviatis, Dao, Hieu, Joty, Shafiq, Kawaguchi, Kenji, Chen, Nancy F., and Kan, Min-Yen
- Subjects
Computer Science - Computation and Language - Abstract
We present the first systematic evaluation examining format bias in performance of large language models (LLMs). Our approach distinguishes between two categories of an evaluation metric under format constraints to reliably and accurately assess performance: one measures performance when format constraints are adhered to, while the other evaluates performance regardless of constraint adherence. We then define a metric for measuring the format bias of LLMs and establish effective strategies to reduce it. Subsequently, we present our empirical format bias evaluation spanning four commonly used categories -- multiple-choice question-answer, wrapping, list, and mapping -- covering 15 widely-used formats. Our evaluation on eight generation tasks uncovers significant format bias across state-of-the-art LLMs. We further discover that improving the format-instruction following capabilities of LLMs across formats potentially reduces format bias. Based on our evaluation findings, we study prompting and fine-tuning with synthesized format data techniques to mitigate format bias. Our methods successfully reduce the variance in ChatGPT's performance among wrapping formats from 235.33 to 0.71 (%$^2$).
- Published
- 2024
28. A proof of the Lewis-Reiner-Stanton conjecture for the Borel subgroup
- Author
-
Ha, Le Minh, Hai, Nguyen Dang Ho, and Van Nghia, Nguyen
- Subjects
Mathematics - Rings and Algebras ,Mathematics - Algebraic Topology ,Mathematics - Representation Theory ,05E10, 05A30, 55N10, 13A50, 20J06 - Abstract
For each parabolic subgroup $P$ of the general linear group $GL_n(\mathbb{F}_q)$, a conjecture due to Lewis, Reiner and Stanton \cite{LewisReinerStanton2017} predicts a formula for the Hilbert series of the space of invariants $\mathcal{Q}_m(n)^{P}$ where $\mathcal{Q}_m(n)$ is the quotient ring $\mathbb{F}_q[x_1,\ldots,x_n]/(x_1^{q^m},\ldots,x_n^{q^m})$. In this paper, we prove the conjecture for the Borel subgroup $B$ by constructing a linear basis for $mathcal{Q}_m(n)^B$. The construction is based on an operator $\delta$ which produces new invariants from old invariants of lower ranks. We also upgrade the conjecture of Lewis, Reiner and Stanton by proposing an explicit basis for the space of invariants for each parabolic subgroup., Comment: to appear in Trans. Amer. Math. Soc
- Published
- 2024
29. Expanding access to HIV testing through Canadian community pharmacies: findings from the APPROACH study
- Author
-
Deborah V. Kelly, Jason Kielly, Christine Hughes, Jacqueline Gahagan, Shabnam Asghari, Stephanie Hancock, Kimberley Burt, Petra Smyczek, Carmen Charlton, and Hai Nguyen
- Subjects
HIV ,Point-of-care testing ,Rapid HIV testing ,Community pharmacy ,Pharmacist ,Implementation ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background There is a need for acceptable and feasible HIV testing options to ensure people living with HIV know their status so they can access care. Pharmacist-provided HIV point-of-care testing (POCT) may overcome testing barriers, including privacy concerns, testing wait times, and improve accessibility. In the APPROACH study, we aimed to develop and assess an HIV POCT program in community pharmacies for future scale up and evaluation. This paper describes the program uptake, participant and pharmacist experiences, and implementation factors. Methods A pharmacist-provided HIV POCT program was offered in 4 pharmacies in two Canadian provinces. A mixed methods design incorporated self-report questionnaire data, participant telephone interviews, pharmacist focus groups, workload analysis, and situational analysis to assess the uptake, acceptability and feasibility of the HIV POCT program. Results Over the 6-month pilot, 123 HIV tests were performed. One new case of HIV was identified; this participant was linked with confirmatory testing and HIV care. Participants were predominantly male (76%), with a mean age of 35 years. This was the first HIV test for 27% participants, and 75% were at moderate to very high risk of undiagnosed HIV infection, by Denver HIV Risk Score. Questionnaires and telephone interviews showed participants were very satisfied with the program; 99% agreed HIV POCT should be routinely offered in pharmacies and 78% were willing to pay for the service. Participants felt the pharmacy was convenient, discreet, and that the pharmacist was supportive and provided education about how to reduce their future risk. Pharmacists felt prepared, confident, and expressed professional satisfaction with offering HIV POCT. Community and public health supports, clear linkage to care plans to refer participants with positive HIV POCT results, and provision of counselling tools were important enabling factors for the program. Pharmacist remuneration, integration with existing healthcare systems, and support for ongoing promotion of HIV POCT availability in pharmacies were identified as needs for future scale-up and sustainability. Conclusions A successful model of pharmacy-based POCT, including linkage to care, was developed. Further research is needed to determine the effectiveness and cost-effectiveness of this approach in finding new diagnoses and linking them with care. Trial registration Retrospectively registered with clinicaltrials.gov ( NCT03210701 ) on July 6, 2017.
- Published
- 2020
- Full Text
- View/download PDF
30. Enterovirus D68: a test case for the use of immunological surveillance to develop tools to mitigate the pandemic potential of emerging pathogens
- Author
-
Hai Nguyen-Tran, Sang Woo Park, Kevin Messacar, Samuel R Dominguez, Matthew R Vogt, Sallie Permar, Perdita Permaul, Michelle Hernandez, Daniel C Douek, Adrian B McDermott, C Jessica E Metcalf, Bryan Grenfell, and Alicen B Spaulding
- Subjects
Medicine (General) ,R5-920 ,Microbiology ,QR1-502 - Published
- 2022
- Full Text
- View/download PDF
31. Ambulatory cephalosporin prescribing practices at a freestanding children’s hospital network
- Author
-
Hai Nguyen-Tran, Christine E. MacBrayne, Sarah K. Parker, and Nicole M. Poole
- Subjects
Infectious and parasitic diseases ,RC109-216 ,Public aspects of medicine ,RA1-1270 - Published
- 2022
- Full Text
- View/download PDF
32. Improper Estimation of Thermodynamic Parameters in Adsorption Studies with Distribution Coefficient KD (qe/Ce) or Freundlich Constant (KF): Considerations from the Derivation of Dimensionless Thermodynamic Equilibrium Constant and Suggestions
- Author
-
Hai Nguyen Tran
- Subjects
Physical and theoretical chemistry ,QD450-801 - Abstract
Adsorption processes often include three important components: kinetics, isotherm, and thermodynamics. In the study of solid–liquid adsorption, “standard” thermodynamic equilibrium constant KEqo; dimensionless) plays an essential role in accurately calculating three thermodynamic parameters: the standard Gibbs energy change (∆G°; kJ/mol), the standard change in enthalpy (∆H°; kJ/mol), and the standard change in entropy [∆S°; J/(mol × K)] of an adsorption process. Misconception of the derivation of the KEqo constant that can cause calculative errors in values (magnitude and sign) of the thermodynamic parameters has been intensively reflected through certain kinds of papers (i.e., letters to editor, discussions, short communications, and correspondence like comment/rebuttal). The distribution coefficient (KD) and Freundlich constant (KF) have been intensively applied for calculating the thermodynamic parameters. However, a critical question is whether KD or KF is equal to KEqo. This paper gives (1) thorough discussion on the derivation of thermodynamic equilibrium constant of solid–liquid adsorption process, (2) reasonable explanation on the inconsistency of (direct and indirect) application of KD or KF for calculating the thermodynamic parameters based on the derivation of KEqo, and (3) helpful suggestions for improving the quality of papers published in this field.
- Published
- 2022
- Full Text
- View/download PDF
33. Evaluating the Properties of Railway Ballast Using Spectral Analysis of Ground Penetrating Radar Signal Based on Optimized Variational Mode Decomposition
- Author
-
Wael Zatar, Xia Hua, Gang Chen, Hai Nguyen, and Hien Nghiem
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Ground penetrating radar (GPR) has been widely applied in the assessment of railway ballast conditions (fouling, moisture) by using the spectrum of the tested GPR signal. However, the drawbacks of the low time-frequency resolution and mode mixing prevent the traditional spectrum methods from a wide application. This paper uses the advanced time-frequency analysis of GPR signal based on optimized variational mode decomposition to extract the features of ballast. The new approach overperforms the conventional frequency spectrum methods of GPR signal processing by giving a clear and quantitative assessment of ballast signals. Experimental results of GPR with dry and wet fouled ballasts demonstrate that, by comparison with the feature extraction method of conventional spectrum methods such as spectrogram and wavelet, the feature extraction method based on the optimized VMD has much better separability and quantitative identification capability.
- Published
- 2022
- Full Text
- View/download PDF
34. Tolvaptan Add-on Therapy to Overcome Loop Diuretic Resistance in Acute Heart Failure With Renal Dysfunction (DR-AHF): Design and Rationale
- Author
-
Nhat Giang Minh, Hai Nguyen Hoang, Daichi Maeda, and Yuya Matsue
- Subjects
acute heart failure ,worsening renal function (WRF) ,loop diuretic resistance ,vasopressin-2 receptor antagonist ,diuretic combination therapy ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
BackgroundDiuretic Resistance in Acute Heart Failure (DR-AHF) was designed to demonstrate the effectiveness of the early tolvaptan (a vasopressin-2 receptor antagonist) add-on therapy in patients with AHF with renal dysfunction and to provide clinical evidence of loop diuretic resistance.Methods and ResultsThis single-centered, open-labeled, randomized, and controlled trial enrolled 128 patients hospitalized with AHF, as participants. These patients with a wet-warm phenotype, whose estimated glomerular filtration rates are of ≥15 ml/min/1.73 m2 and ≤ 60 ml/min/1.73 m2, with a cumulative urine output of
- Published
- 2022
- Full Text
- View/download PDF
35. Camber effect on the stability and power performance of a right-swing hydrofoil turbine
- Author
-
Hai Nguyen Le Dang, Tuyen Quang Le, Dasom Jeong, and Jin Hwan Ko
- Subjects
Right-swing turbine ,Camber ,Stability ,Power efficiency ,Ocean engineering ,TC1501-1800 ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 - Abstract
In this study, performance of a right-swing turbine with a cambered hydrofoil was analyzed by CFD numerical simulations to assess its stability and power efficiency. It is found from the analysis that the right-swing trajectory, which is close to the kinematics of flying or swimming creatures, has advantages over the left-swing trajectory in terms of stability with a slight loss of the power efficiency. A cambered hydrofoil can be utilized to offset this loss, but doing so negatively affects the stability at the turning positions of the flapping motion. Consequently, in order to guarantee stability and high efficiency of a right-swing hydrofoil turbine, camber shapes adjustable at the positions of flapping motion, which is an excellent feature of flight and swimming creatures, are mandatory. Eventually, the analysis results of this study will be utilized to develop a high-performance flapping hydrofoil turbine.
- Published
- 2022
- Full Text
- View/download PDF
36. High-speed 2D and 3D mid-IR imaging with an InGaAs camera
- Author
-
Eric O. Potma, David Knez, Martin Ettenberg, Matthew Wizeman, Hai Nguyen, Tom Sudol, and Dmitry A. Fishman
- Subjects
Applied optics. Photonics ,TA1501-1820 - Abstract
Recent work on mid-infrared (MIR) detection through the process of non-degenerate two-photon absorption (NTA) in semiconducting materials has shown that wide-field MIR imaging can be achieved with standard Si cameras. While this approach enables MIR imaging at high pixel densities, the low nonlinear absorption coefficient of Si prevents fast NTA-based imaging at lower illumination doses. Here, we overcome this limitation by using InGaAs as the photosensor. Taking advantage of the much higher nonlinear absorption coefficient of this direct bandgap semiconductor, we demonstrate high-speed MIR imaging up to 500 fps with under 1 ms exposure per frame, enabling 2D or 3D mapping without pre- or post-processing of the image.
- Published
- 2021
- Full Text
- View/download PDF
37. Online learning amid Covid-19 pandemic: students' experience and satisfaction
- Author
-
Pham Thach, Phuong Lai, Vinh Nguyen, and Hai Nguyen
- Subjects
e-Learning ,Covid-19 ,Satisfaction ,Course content ,Interaction ,Online Pedagogy ,Theory and practice of education ,LB5-3640 - Abstract
and learning to online mode. This had huge impact on the students, especially for those who had not been used to being online for learning before. This mixed methods study utilized correlation, factor analysis and multiple regression techniques to identify significant predictors of students’ satisfaction with online learning in a higher education institution in Vietnam amid COVID-19 Pandemic. The study results show that learners’ interaction with content, peers and instructors correlated to and predicted student satisfaction. The study also indicated that although students valued the chance to be online for learning during the historic time, they viewed that interaction was limited and instructors should improve online teaching pedagogy. These findings provide learners, teachers and curriculum developers with new insights into learner interaction and its relation to course contents, teaching pedagogy and learning satisfaction in an Asian context.
- Published
- 2021
- Full Text
- View/download PDF
38. Transitions in diatom assemblages and pigments through dry and wet season conditions in the Red River, Hanoi (Vietnam)
- Author
-
Thi Duong, Hai Nguyen, Thi Le, Trung Nguyen, Thi Tran, Nhu Le, Dinh Dang, Thi Vu, Virginia Panizzo, and Suzanne McGowan
- Subjects
Chlorophyll and carotenoid pigments ,diatom biofil ,Plant ecology ,QK900-989 - Abstract
Background and aims – Biomonitoring is an important tool for assessing river water quality, but is not routinely applied in tropical rivers. Marked hydrological changes can occur between wet and dry season conditions in the tropics. Thus, a prerequisite for ecological assessment is that the influence of ‘natural’ hydrological change on biota can be distinguished from variability driven by water quality parameters of interest. Here we aimed to (a) assess seasonal changes in water quality, diatoms and algal assemblages from river phytoplankton and artificial substrates through the dry-wet season transition (February–July 2018) in the Red River close to Hanoi and (b) evaluate the potential for microscopic counts and high-performance liquid chromatography (HPLC) analysis of chlorophyll and carotenoid pigments for biomonitoring in large tropical rivers.Methods – River water (phytoplankton) and biofilms grown on artificial glass substrates were sampled monthly through the dry (February–April) to wet (May–August) season transition and analysed via microscopic and HPLC techniques.Key results – All phototrophic communities shifted markedly between the dry and wet seasons. Phytoplankton concentrations were low (c. thousands of cells/mL) and declined as the wet season progressed. The dominant phytoplankton taxa were centric diatoms (Aulacoseira granulata and Aulacoseira distans) and chlorophytes (Scenedesmus and Pediastrum spp.), with chlorophytes becoming more dominant in the wet season. Biofilm diatoms were dominated by Melosira varians, and areal densities declined in the wet season when fast-growing pioneer diatom taxa (e.g. Achnanthidium minutissimum, Planothidium lanceolatum) and non-degraded Chlorophyll a concentrations increased, suggesting active phytobenthos growth in response to scour damage. Otherwise, a-phorbins were very abundant in river seston and biofilms indicating in situ Chlorophyll a degradation which may be typical of tropical river environments. The very large range of total suspended solids (reaching > 120 mg/L) and turbidity appears to be a key driver of photoautotrophs through control of light availability.Conclusions – Hydrological change and associated turbidity conditions exceed nutrient influences on photoautotrophs at inter-seasonal scales in this part of the Red River. Inter-seasonal differences might be a useful measure for biomonitoring to help track how changes in suspended solids, a major water quality issue in tropical rivers, interact with other variables of interest.
- Published
- 2019
- Full Text
- View/download PDF
39. The Characteristics of Aftershock Activities of Dien Bien Earthquake on 19 February 2001 and Their Relation to the Local Geomorphological, Tectonic Features
- Author
-
Lu Ngo Thi, Hang Phung Thi Thu, Tuyen Nguyen Huu, Giang Ha Thi, and Hai Nguyen Thanh
- Subjects
aftershocks ,dien bien earthquake ,morphotectonic ,Ecology ,QH540-549.5 - Abstract
This article examines in detail the characteristics of Dien Bien earthquake on 19 February 2001 and its aftershocks. On the basis of the temporal development of aftershocks and the spatial distribution of tectonic faults, five aftershock series have been determined. The analysis of spatial distribution and temporal evolution of these five aftershock series has clarified the development in the source zone of Dien Bien earthquake, which is closely related to the active and recent activities of tectonic faults in the area, especially Lai Chau Dien Bien fault. The comparison between characteristics of aftershock activities of Dien Bien earthquake and geomorphological features as well as tectonic activities in the area has indicated that the magnitude of these aftershocks and their temporal evolution (early or late) depend not only on the closer or further distance compared to the mainshock and the active faults that cause them but also on terrain elevation, slope index, lineament density and their positions relative to other tectonic faults in the studied area.
- Published
- 2019
- Full Text
- View/download PDF
40. Characterization of Cell Free Plasma Methyl-DNA From Xenografted Tumors to Guide the Selection of Diagnostic Markers for Early-Stage Cancers
- Author
-
Ling Liu, Jinghua Feng, Julian Polimeni, Manli Zhang, Hai Nguyen, Urmi Das, Xu Zhang, Harminder Singh, Xiao-Jian Yao, Etienne Leygue, Sam K. P. Kung, and Jiuyong Xie
- Subjects
whole-genome bisulfite sequencing ,xenograft mice ,early stage cancers ,diagnosis ,cell free methyl-DNA ,colon cancer ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Circulating cell-free methyl-DNA (mcfDNA) contains promising cancer markers but its low abundance and possibly diverse origin pose challenges toward the accurate diagnosis of early stage cancers. By whole-genome bisulfite sequencing (WGBS) of cell-free DNA (cfDNA) from about 0.5 mL plasma of mice xenografted with human tumors, we obtained and aligned the reads to the human genome, filtered out the mouse and carrier bacterial sequences, and confirmed the tumor origin of methyl-cfDNA (mctDNA) by methylation-sensitive restriction enzyme digestion prior to species-specific PCR. We estimated that human tumor-specific reads (ctDNA) or mctDNA comprised about 0.29 or 0.01%, respectively of the xenograft mouse cfDNA, and about 0.029 or 0.001% of the cfDNA of human early stage cancer patients. Similar WGBS of early stage (0-II, node- and metastasis-free) breast, lung or colorectal cancer samples identified hundreds of specific DMRs (differentially methylated regions) compared to healthy controls. Their association with tumourigenesis was supported by stage-dependent methylation, tumor suppressor or oncogene clusters, and genes also identified in the xenograft samples. Using 20 three-cancer-common and 17 colorectal cancer-specific DMRs in combination (top 0.0018% of the WGBS methylation clusters) was sufficient to distinguish the stage I colorectal cancers from breast and lung cancers and healthy controls. Our data thus confirmed the tumor origin of mctDNA by sequence specificity, and provide a selection threshold for authentic tumor mctDNA markers toward precise diagnosis of early stage cancers solely by top DMRs in combination.
- Published
- 2021
- Full Text
- View/download PDF
41. Association between levels of thiamine intake, diabetes, cardiovascular diseases and depression in Korea: a national cross-sectional study
- Author
-
Hai Nguyen Duc, Hojin Oh, In Mo Yoon, and Min-Sun Kim
- Subjects
KNHANES ,Mental health ,Non-communicable diseases ,Thiamine intake ,Nutrition. Foods and food supply ,TX341-641 ,Medicine - Abstract
The present study aimed to determine thiamine intake levels and the association between thiamine intake, diabetes, cardiovascular diseases and mental health. Participants were interviewed to obtain data on socio-demographic characteristics, lifestyle, current medications, medical and family history. The daily intake of thiamine was assessed by a 24-h recall. The mean age of the 34 700 study subjects was 42⋅9 years (sd 22⋅8, min–max: 1–80) and 19 342 (55⋅7 %) were women. The levels of thiamine intake were 1⋅126 mg (2016), 1⋅115 mg (2017) and 1⋅087 mg (2018) for women, which were equal to or only slightly above the recommended intake of 1⋅10 mg/d for women. The levels of thiamine intake from 2014–15 and 2016–18 significantly decreased. The estimated percentage of insufficient thiamine intake was 37⋅8 % (95 % CI 37⋅3, 38⋅4). Multivariable regression analysis adjusted for potential confounders showed that thiamine intake was critically associated with lower risks of hypertension, MI or angina, type 2 diabetes, depression and dyslipidemia. The daily thiamine intake from food can reversal the risks of hypertension (OR 0⋅95; 95 % CI 0⋅90, 0⋅99), MI or angina (OR 0⋅84; 95 % CI 0⋅74, 0⋅95), type 2 diabetes (OR 0⋅86; 95 % CI 0⋅81, 0⋅93), depression (OR 0⋅90; 95 % CI 0⋅83, 0⋅97) and dyslipidemia (OR 0⋅90; 95 % CI 0⋅86, 0⋅95), respectively. Further works are needed to identify the effects of thiamine and non-communicable diseases (NCDs) and mental health. A preventive thiamine supplementation strategy should be adopted to target NCDs and mental health and risk factors associated with thiamine deficiency. The optimisation of NCD control and mental health protection is also a vital integral part of Korea's public health system.
- Published
- 2021
- Full Text
- View/download PDF
42. Predicting GPR Signals from Concrete Structures Using Artificial Intelligence-Based Method
- Author
-
Wael Zatar, Tu T. Nguyen, and Hai Nguyen
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
This paper presents the application of an Artificial Intelligence-based method in analyzing the effects of environmental conditions, chloride contamination in concrete, and surface corrosion of rebars on the amplitude of Ground Penetrating Radar (GPR) signals. Six reinforced concrete slabs with different chloride contamination mixtures were fabricated and tested. GPR data were collected under various temperature and ambient humidity combinations. A total of 288 rebar picks were used for training, validation, and testing the proposed Artificial Neural Network (ANN) model. Multiple ANN model configurations with a variation in learning algorithms and the number of nodes in the hidden layer were explored to obtain the optimal model for the nondestructive data. It is shown that the “trainlm” learning algorithm produced the high accuracy prediction of the reflection amplitude of GPR signals. The sensitivity analysis was also conducted with the ANN model to investigate the effects of the input on the output parameters. Results from the sensitivity analysis revealed that the GPR reflection amplitudes were more sensitive to the changes of temperature parameter (TEM) and chloride contamination level (CCL), while they were less sensitive to the variation of ambient relative humidity (ARH) and rust condition on the rebar surface (CSR).
- Published
- 2021
- Full Text
- View/download PDF
43. Trajectories of healthy ageing among older adults with multimorbidity: A growth mixture model using harmonised data from eight ATHLOS cohorts.
- Author
-
Hai Nguyen, Dario Moreno-Agostino, Kia-Chong Chua, Silia Vitoratou, and A Matthew Prina
- Subjects
Medicine ,Science - Abstract
ObjectivesIn this study we aimed to 1) describe healthy ageing trajectory patterns, 2) examine the association between multimorbidity and patterns of healthy ageing trajectories, and 3) evaluate how different groups of diseases might affect the projection of healthy ageing trajectories over time.Setting and participantsOur study was based on 130880 individuals from the Ageing Trajectories of Health: Longitudinal Opportunities and Synergies (ATHLOS) harmonised dataset, as well as 9171 individuals from Waves 2-7 of the English Longitudinal Study of Ageing (ELSA).MethodsUsing a healthy ageing index score, which comprised 41 items, covering various domains of health and ageing, as outcome, we employed the growth mixture model approach to identify the latent classes of individuals with different healthy ageing trajectories. A multinomial logistic regression was conducted to assess if and how multimorbidity status and multimorbidity patterns were associated with changes in healthy ageing, controlled for sociodemographic and lifestyle risk factors.ResultsThree similar patterns of healthy ageing trajectories were identified in the ATHLOS and ELSA datasets: 1) a 'high stable' group (76% in ATHLOS, 61% in ELSA), 2) a 'low stable' group (22% in ATHLOS, 36% in ELSA) and 3) a 'rapid decline' group (2% in ATHLOS, 3% in ELSA). Those with multimorbidity were 1.7 times (OR = 1.7, 95% CI: 1.4-2.1) more likely to be in the 'rapid decline' group and 11.7 times (OR = 11.7 95% CI: 10.9-12.6) more likely to be in the 'low stable' group, compared with people without multimorbidity. The cardiorespiratory/arthritis/cataracts group was associated with both the 'rapid decline' and the 'low stable' groups (OR = 2.1, 95% CI: 1.2-3.8 and OR = 9.8, 95% CI: 7.5-12.7 respectively).ConclusionHealthy ageing is heterogeneous. While multimorbidity was associated with higher odds of having poorer healthy ageing trajectories, the extent to which healthy ageing trajectories were projected to decline depended on the specific patterns of multimorbidity.
- Published
- 2021
- Full Text
- View/download PDF
44. Arsenic and Heavy Metals in Soils and Plants near Sulfide Mines: Implications for Phytoremediation and Phytomanagement
- Author
-
Ha, Nguyen Thi Hoang, Hieu, Do Trung, Anh, Hoang Thi Phuong, Hien, Pham Thu, Nga, Tran Thi Huyen, Anh, Bui Thi Kim, Hai, Nguyen Thi, Duong, Dang Bao, Duong, Van-Hao, Duc, Nguyen Anh, and Kim, Kyoung-Woong
- Published
- 2024
- Full Text
- View/download PDF
45. Removal of ammonium from water by a KOH-treated bentonite biochar composite
- Author
-
Hoang-Minh, Thao, Hai, Nguyen Thi, Hieu, Do Trung, Hoai, Ta Thi, Van Dong, Bui, Dung, Luu Viet, and Ha, Nguyen Thi Hoang
- Published
- 2024
- Full Text
- View/download PDF
46. Laparoscopic versus open total gastrectomy for T4a gastric cancer: a propensity score-matched analysis of long-term outcomes
- Author
-
Long, Vo Duy, Nguyen, Doan Thuy, Thong, Dang Quang, Dat, Tran Quang, Hai, Nguyen Viet, Vuong, Nguyen Lam, and Bac, Nguyen Hoang
- Published
- 2024
- Full Text
- View/download PDF
47. DIAS: A Data-Informed Active Subspace Regularization Framework for Inverse Problems
- Author
-
Hai Nguyen, Jonathan Wittmer, and Tan Bui-Thanh
- Subjects
inverse problems ,regularization ,active subspaces ,data-informed regularization ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
This paper presents a regularization framework that aims to improve the fidelity of Tikhonov inverse solutions. At the heart of the framework is the data-informed regularization idea that only data-uninformed parameters need to be regularized, while the data-informed parameters, on which data and forward model are integrated, should remain untouched. We propose to employ the active subspace method to determine the data-informativeness of a parameter. The resulting framework is thus called a data-informed (DI) active subspace (DIAS) regularization. Four proposed DIAS variants are rigorously analyzed, shown to be robust with the regularization parameter and capable of avoiding polluting solution features informed by the data. They are thus well suited for problems with small or reasonably small noise corruptions in the data. Furthermore, the DIAS approaches can effectively reuse any Tikhonov regularization codes/libraries. Though they are readily applicable for nonlinear inverse problems, we focus on linear problems in this paper in order to gain insights into the framework. Various numerical results for linear inverse problems are presented to verify theoretical findings and to demonstrate advantages of the DIAS framework over the Tikhonov, truncated SVD, and the TSVD-based DI approaches.
- Published
- 2022
- Full Text
- View/download PDF
48. Explanation of the Convolutional Neural Network Classifying Chest X-Ray Images Supporting Pneumonia Diagnosis
- Author
-
Hai Nguyen, Hoang Huynh, Toan Tran, and Hiep Huynh
- Subjects
explanation ,chest images ,x-ray images ,pneumonia ,convolutional neural network ,disease diagnosis ,Technology (General) ,T1-995 - Abstract
Medical images are valuable sources for disease diagnosis. Besides, advancements in deep learning in recent years havebeen supporting disease diagnosis methods based on images to obtain numerous achievements. However, deep learningalgorithms still work as a black-box so it is difficult to interpret output from these algorithms. In this study, we propose aconvolutional network architecture to classify Chest X-ray images as well as apply explanation approaches for trainedmodels to support disease diagnosis. The proposed method provides insights in medical images to support Pneumoniadiagnosis.
- Published
- 2020
- Full Text
- View/download PDF
49. Multimorbidity patterns in low-middle and high income regions: a multiregion latent class analysis using ATHLOS harmonised cohorts
- Author
-
Josep Maria Haro, Hai Nguyen, Matthew Prina, Daniel Fernandez, Ivet Bayes-Marin, Albert Sanchez-Niubo, Laia Egea-Cortés, and Beatriz Olaya
- Subjects
Medicine - Abstract
Objectives Our aim was to determine clusters of non-communicable diseases (NCDs) in a very large, population-based sample of middle-aged and older adults from low- and middle-income (LMICs) and high-income (HICs) regions. Additionally, we explored the associations with several covariates.Design The total sample was 72 140 people aged 50+ years from three population-based studies (English Longitudinal Study of Ageing, Survey of Health, Ageing and Retirement in Europe Study and Study on Global Ageing and Adult Health) included in the Ageing Trajectories of Health: Longitudinal Opportunities and Synergies (ATHLOS) project and representing eight regions with LMICs and HICs. Variables were previously harmonised using an ex-post strategy. Eight NCDs were used in latent class analysis. Multinomial models were made to calculate associations with covariates. All the analyses were stratified by age (50–64 and 65+ years old).Results Three clusters were identified: ‘cardio-metabolic’ (8.93% in participants aged 50–64 years and 27.22% in those aged 65+ years), ‘respiratory-mental-articular’ (3.91% and 5.27%) and ‘healthy’ (87.16% and 67.51%). In the younger group, Russia presented the highest prevalence of the ‘cardio-metabolic’ group (18.8%) and England the ‘respiratory-mental-articular’ (5.1%). In the older group, Russia had the highest proportion of both classes (48.3% and 9%). Both the younger and older African participants presented the highest proportion of the ‘healthy’ class. Older age, being woman, widowed and with low levels of education and income were related to an increased risk of multimorbidity. Physical activity was a protective factor in both age groups and smoking a risk factor for the ‘respiratory-mental-articular’.Conclusion Multimorbidity is common worldwide, especially in HICs and Russia. Health policies in each country addressing coordination and support are needed to face the complexity of a pattern of growing multimorbidity.
- Published
- 2020
- Full Text
- View/download PDF
50. Microstructure Formation of Al-Based Alloys in the Presence of Rare Earth Metals (Ce, La) and Mn under High Cooling Rate
- Author
-
Hong, Hai Nguyen, Hoang, Viet Nguyen, Pham, Quang, Ngoc, Quyen Hoang Thi, Hong, Hai Nguyen, Mai, Khanh Pham, Le Minh, Duc, and Van, Vuong Hoang
- Published
- 2024
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.