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LIOUVILLE RESULTS FOR STABLE SOLUTIONS OF QUASILINEAR EQUATIONS WITH WEIGHTS

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Acta Mathematica Scientia 2019年第2期39卷 357-368页

作者： Phuong LE Vu ho Department of Mathematical Economics Banking University of Ho Chi Minh City Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang University Faculty of Mathematics and Statistics Ton Duc Thang University

This paper is devoted to the quasilinear equation ■where p > 2,Ω is a(bounded or unbounded) domain of R^N,w_1,w_2 are nonnegative continuous functions and f is an increasing function. We establish a Liouville type theorem for nontrivial stable solutions of the equation under some mild assumptions on Ω,w_1, w_2 and f, which extends and unifies several results on this topic.

关键词： quasilinear equations stable solutions nonexistence Liouville theorems

Novel CagA ELISA exhibits enhanced sensitivity of Helicobacter pylori CagA antibody

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World Journal of Gastroenterology 2017年第1期23卷 48-59页

作者： Yuichi Matsuo Yasutoshi Kido Junko Akada Seiji Shiota Tran Thanh Binh Tran Thi Huyen Trang ho DQ Dung Pham huu Tung Tran Dinh Tri Ngo P Minh Thuan Le Quang Tam Bui Chi Nam Vu Van Khien Yoshio Yamaoka Department of Environmental and Preventive Medicine Oita University Faculty of Medicine Department of General Medicine Oita University Faculty of Medicine Department of Endoscopy Cho Ray Hospital Department of Molecular Biology 108 Military Central Hospital Department of Endoscopy Daklak Hospital Department of Endoscopy Lao Cai Hospital Department of Hepatogastroentrology 108 Military Center Hospital Department of Medicine-Gastroenterology Baylor College of Medicine and Michael E.De Bakey Veterans Affairs Medical Center

AIMTo develop a novel Helicobacter pylori (H. pylori) CagA antibody enzyme-linked immunosorbent assay (ELISA) suitable for detecting serum anti-CagA antibodies with high *** East Asian-type CagA protein was purified and immobilized for ELISA. Serum samples from 217 Vietnamese individuals (110 H. pylori-infected and 107 uninfected individuals) were applied. Conventional ELISA from Western-type CagA and our East Asian-type CagA ELISA were evaluated by comparing 38 subjects with the Western-type genotype and 72 subjects with the East Asian-type cagA genotype. Histological scores of the gastric mucosa were determined using the updated Sydney System to examine the relationship with anti-CagA antibody *** 70-100 kDa fragments were immobilized on the ELISA plate. In ROC analysis, the area under the curve of our East Asian-type CagA ELISA was comparable to that of conventional CagA ELISA. The sensitivity of the two ELISAs differed depending on the cagA genotype. The sensitivity of East Asian-type CagA ELISA was higher for subjects infected with East Asian-type cagA H. pylori (P < 0.001), and the sensitivity of the conventional CagA ELISA tended to be higher for subjects infected with Western cagA H. pylori (P = 0.056). The titer of anti-CagA antibody tended to correlate with monocyte infiltration scores (r = 0.25, P = 0.058) and was inversely correlated with H. pylori density (r = -0.26, P = 0.043).CONCLUSIONThe novel ELISA is useful to detect anti-CagA antibodies in East Asian countries, and the titer may be a marker for predicting chronic gastritis.

关键词： Helicobacter pylori cagA genotype Anti-CagA antibody Enzyme-linked immunosorbent assay Inflammation Gastritis

Genetic diversity in two threatened species in Vietnam:Taxus chinensis and Taxus wallichiana

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Journal of Forestry Research 2017年第2期28卷 265-272页

作者： Dinh Duy Vu Thi Tuyet Xuan Bui Minh Tam Nguyen Dinh Giap Vu Minh Duc Nguyen Van thang Bui Xiaohua Huang Yi Zhang College of Forestry Northwest A&F UniversityYangling 712100ShaanxiPeople's Republic of China Vietnam National Museum of Nature Vietnam Academy of Science and Technology(VAST)18 Hoang Quoc VietCau GiayHanoiVietnam Institute of Ecology and Biological Resource(VAST) 18 Hoang Quoc VietCau GiayHanoiVietnam Institute of Natural Products Chemistry(VAST) 18 Hoang Quoc VietCau GiayHanoiVietnam Institute of Forest Biotechnology Vietnam Forestry UniversityXuan MaiChuong MyHanoiVietnam

Taxus chinensis and T. wallichiana in have been threatened in their distribution areas in recent decades because of their over-exploitation and reduction and destruction of native habitats. Determining the genetic diversity in populations of the two species will provide guidelines for their protection and preservation. Two hundred and fifteen trees from six populations of T. chinensis and150 sampled trees of T. wallichiana were sampled. Six microsatellite primer pairs selected from 16 primer pairs were used to investigate genetic variation at the population and species levels. Five yielded polymorphic alleles, and among the 13 putative alleles amplified, 11 were polymorphic（accounting for 76.33 %）.Shannon＇s information index（I） and percentage of polymorphic bands（PPB）（I = 0.202 and PPB = 67.22 % for T. chinensis; I = 0.217 and PPB = 65.03 % for T. wallichiana）. Both species had low levels of genetic diversity（mean ho= 0.107, He= 0.121 for T. chinensis; ho= 0.095, He= 0.109 for T. wallichiana）. Genetic differentiation among populations was higher（FST= 0.189） for T. chinensis and lower（0.156） for ***, indicating limited gene flow（Nm） among populations for T. chinensis（0.68） and T. wallichiana（0.65）.Variation among individuals of T. chinensis was 63.59 and73.12 % for T. wallichiana. Thus, the threatened status of the two conifers is related to a lack of genetic diversity. All populations are isolated in small forest remnants. An ex situ conservation site should be established with a new population for these species that comprises all the genetic groups for the best chance to improve their fitness under environmental stresses.

关键词： Taxus populations alleles polymorphic microsatellite Vietnam primer accounting putative destruction

Improved flood susceptibility mapping using a best first decision tree integrated with ensemble learning techniques

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Geoscience Frontiers 2021年第3期12卷 333-342页

作者： Binh Thai Pham Abolfazl Jaafari Tran Van Phong hoang Phan Hai Yen Tran Thi Tuyen Vu Van Luong huu Duy Nguyen Hiep Van Le Loke Kok Foong University of Transport Technology Ha Noi 100000Viet Nam Research Institute of Forests and Rangelands Agricultural ResearchEducation and Extension Organization(AREEO)TehranIran Institute of Geological Sciences Vietnam Academy of Sciences and Technology84 Chua Lang StreetDong daHa NoiViet Nam Department of Geography School of Social EducationVinh UniversityViet Nam Department of Resource and Environment Management School of Agriculture and ResourcesVinh UniversityViet Nam Faculty of Geography VNU University of Science334 Nguyen TraiHa NoiViet Nam Institute of Research and Development Duy Tan UniversityDa Nang 550000Viet Nam Department for Management of Science and Technology Development Ton Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityViet Nam

Improving the accuracy of flood prediction and mapping is crucial for reducing damage resulting from flood *** this study,we proposed and validated three ensemble models based on the Best First Decision Tree(BFT)and the Bagging(Bagging-BFT),Decorate(Bagging-BFT),and Random Subspace(RSS-BFT)ensemble learning techniques for an improved prediction of flood susceptibility in a spatially-explicit manner.A total number of 126 historical flood events from the Nghe An Province(Vietnam)were connected to a set of 10 flood influencing factors(slope,elevation,aspect,curvature,river density,distance from rivers,flow direction,geology,soil,and land use)for generating the training and validation *** models were validated via several performance metrics that demonstrated the capability of all three ensemble models in elucidating the underlying pattern of flood occurrences within the research area and predicting the probability of future flood *** on the Area Under the receiver operating characteristic Curve(AUC),the ensemble Decorate-BFT model that achieved an AUC value of 0.989 was identified as the superior model over the RSS-BFT(AUC=0.982)and Bagging-BFT(AUC=0.967)models.A comparison between the performance of the models and the models previously reported in the literature confirmed that our ensemble models provided a reliable estimate of flood susceptibilities and their resulting susceptibility maps are trustful for flood early warning systems as well as development of mitigation plans.

关键词： Machine learning Ensemble learners Hybrid modeling

Ecoregional variations of aboveground biomass and stand structure in evergreen broadleaved forests

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Journal of Forestry Research 2020年第5期31卷 1713-1722页

作者： Tran Van Do Mamoru Yamamoto Osamu Kozan Vo Dai Hai Phung Dinh Trung Nguyen Toan thang Lai Thanh Hai Vu Thanh Nam Trieu Thai Hung hoang Van thang Tran Duc Manh Cao Chi Khiem Vu Tien Lam Nguyen Quang Hung Tran hoang Quy Pham Quang Tuyen Trinh Ngoc Bon Nguyen Thi Thu Phuong Ninh Viet Khuong Nguyen Van Tuan Dang Thi Hai Ha Tran Hai Long Dang Van Thuyet Dang Thinh Trieu Nguyen Van Thinh Tran Anh Hai Duong Quang Trung Nguyen Van Bich Dinh Hai Dang Pham Tien Dung Nguyen Huy hoang Le Thi Hanh Phan Minh Quang Nguyen Thi Thuy Huong hoang Thanh Son Nguyen Thanh Son Nguyen Thi Van Anh Nguyen Thi hoai Anh Pham Dinh Sam hoang Thi Nhung hoang Van Thanh Nguyen huu Thinh Tran hong Van ho Trung Luong Bui Kieu Hung Research Institute for Sustainable Humanosphere Kyoto UniversityUjiKyotoJapan Silviculture Research Institute Vietnamese Academy of Forest SciencesNorth Tu LiemHanoiVietnam Center for Southeast Asian Studies Kyoto UniversityKyotoJapan Vietnamese Academy of Forest Sciences North Tu LiemHanoiVietnam Vietnam Administration of Forestry No.2 Ngoc HaBa DinhHanoiVietnam

Biotic and abiotic factors control aboveground biomass(AGB)and the structure of forest *** study analyses the variation of AGB and stand structure of evergreen broadleaved forests among six ecoregions of Vietnam.A data set of 1731-ha plots from 52 locations in undisturbed old-growth forests was *** results indicate that basal area and AGB are closely correlated with annual precipitation,but not with annual temperature,evaporation or hours of *** area and AGB are positively correlated with trees>30 cm *** areas surveyed(52.6%)in these old-growth forests had AGB of 100–200 Mg ha^-1;5.2%had AGB of 400–500 Mg ha^-1,and 0.6%had AGB of>800 Mg ha^-*** percent of the areas surveyed had stand densities of 300–600 ***^-1,and 64%had basal areas of 20–40 m^2 ha^-*** is an important factor influencing the AGB of old-growth,evergreen broadleaved forests in *** causing the loss of large-diameter trees(e.g.,>100 cm DBH)affects AGB but may not seriously affect stand density.

关键词： Aboveground biomass Carbon storage Climatic variables Ecoregion Edaphic variables Oldgrowth forest

Ensemble machine learning models based on Reduced Error Pruning Tree for prediction of rainfall-induced landslides

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International Journal of Digital Earth 2021年第5期14卷 575-596页

作者： Binh Thai Pham Abolfazl Jaafari Trung Nguyen-Thoi Tran Van Phong huu Duy Nguyen Neelima Satyam Md Masroor Sufia Rehman Haroon Sajjad Mehebub Sahana Hiep Van Le Indra Prakash Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityViet Nam Research Institute of Forests and Rangelands Agricultural ResearchEducationand Extension Organization(AREEO)TehranIran Institute of Geological Sciences Vietnam Academy of Sciences and TechnologyHanoiViet Nam Faculty of Geography V.N.U.University of ScienceVietnam National UniversityHanoiViet Nam Discipline of Civil Engineering Indian Institute of Technology IndoreMadhya PradheshIndia Department of Geography Jamia Millia IslamiaNew DelhiIndia School of Environment Education and DevelopmentUniversity of ManchesterManchesterUK Institute of Research and Development Duy Tan UniversityDa NangViet Nam DDG(R)Geological Survey of India GujaratIndia

In this paper,we developed highly accurate ensemble machine learning models integrating Reduced Error Pruning Tree(REPT)as a base classifier with the Bagging(B),Decorate(D),and Random Subspace(RSS)ensemble learning techniques for spatial prediction of rainfallinduced landslides in the Uttarkashi district,located in the Himalayan range,*** do so,a total of 103 historical landslide events were linked to twelve conditioning factors for generating training and validation *** Mean Square Error(RMSE)and Area Under the receiver operating characteristic Curve(AUC)were used to evaluate the training and validation performances of the *** results showed that the single REPT model and its derived ensembles provided a satisfactory accuracy for the prediction of *** D-REPT model with RMSE=0.351 and AUC=0.907 was identified as the most accurate model,followed by RSS-REPT(RMSE=0.353 and AUC=0.898),B-REPT(RMSE=0.396 and AUC=0.876),and the single REPT model(RMSE=0.398 and AUC=0.836),*** prominent ensemble models proposed and verified in this study provide engineers and modelers with insights for development of more advanced predictive models for different landslide-susceptible areas around the world.

关键词： Machine learning ensemble modeling Bagging Decorate Random Subspace

Antibiotic usage in surgical sperm retrievals among IVF centers

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Asian Journal of Andrology 2022年第6期24卷 633-638页

作者： Le Dang Khoa Ngo Dinh Trieu Vy Nguyen Minh Tai Loc Le Duc thang Dang Tuan Anh Nguyen Phuc Hieu Giang Huynh Nhu Nguyen Dinh Tao Le hoang David J Handelsman IVFTA Tam Anh General HospitalHo Chi Minh 700000Vietnam IVFTA Tam Anh General HospitalHa Noi 100000Vietnam IVF Center 16A Ha Dong HospitalHa Noi 100000Vietnam ANZAC Research Institute University of Sydney and Concord Repatriation General HospitalHospital RoadConcordNSW 2139Australia

Surgical sperm retrieval(SSR)is currently one of the most common procedures in in vitro fertilization(IVF).however,a gap between the guidelines and routine clinical practice regarding antibiotic use in sSR,which might lead to antibiotic resistance,is a challenging problem worldwide.A cross-sectional survey was conducted from May 1,2021,to July 15,2021,to investigate antibiotic usage by medical professionals when performing SSR in IVF centers in *** confidential questionnaire comprised 12 items,including characteristics of the study population,awareness of antimicrobial resistance,attitude toward prescribing antibiotics,and current practice of prescribing antibiotics when performing *** were completed by 30 of 45 registered IVF centers(66.7%).Among 67 physicians working at those centers,the age and work-experience years(mean±standard deviation[s.d.])were 38.6±6.6 years and 11.2±7.0 years,*** 60%of them held a degree in Obstetrics and Gynecology,and over four-fifths were *** respondents"often/very often/always"raised awareness of antimicrobial resistance to their patients(83.3%),but only half of them"often/occasionally"prescribed antibiotics to patients with SSR in cases where the prescription would be *** one-tenth of respondents followed the recommendation from the American Urological Association using"prophylaxis only"for SSR *** more invasive SSR,physicians tended to prescribe more complicated and sometimes inappropriate *** conclusion,antibiotic usage in SSR was not always appropriate among IVF *** studies may define specific recommendations for regimens,intervention strategies,and programs to promote appropriate antibiotic use for SSR patients among IVF specialists.

关键词： antibiotic usage in vitro fertilization prophylaxis surgical sperm retrieval treatment

Favipiravir and its potentials in COVID-19 pandemic:An update

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Asian Pacific Journal of Tropical Medicine 2021年第10期14卷 433-455页

作者： Dao Ngoc Hien Tam Ahmad T Qarawi Mai Ngoc Luu Morgan Turnage Linh Tran Gehad Mohamed Tawfik Le huu Nhat Minh Nguyen Tien Huy Tatsuo Iiyama Kyoshi Kita Kenji Hirayama Online Research Club School of Tropical Medicine and Global HealthNagasaki UniversityNagasaki 852-8523Japan Asia Shine Trading&Service CO.LTD. Ho Chi Minh City 700000Vietnam Essen Healthcare BronxNew York 10461 USA Department of Internal Medicine University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh City 700000Vietnam American University of the Caribbean CupecoySint Maarten Institute of Fundamental and Applied Sciences Duy Tan UniversityHo Chi Minh City 700000Vietnam Faculty of Natural Sciences Duy Tan UniversityDa Nang City 550000Vietnam Department of Otorhinolaryngology Faculty of MedicineAin Shams UniversityCairoEgypt Methodist hospital MerrillvilleIndianaUnited States School of Tropical Medicine and Global Health Nagasaki University1-12-4 SakamotoNagasaki 852-8523Japan Department of International Trials Center of Clinical SciencesNational Center for Global Health and Medicine(NCGM)TokyoJapan

The COVID-19 pandemic has caused millions of deaths and hundreds of millions of confirmed infections *** pandemic has prompted researchers to produce medications or vaccines to reduce or stop the progression and spread of this disease.A variety of previously licensed and marketed medications are being tested for the treatment and recurrence of SARS-CoV2,including favipiravir(Avigan).Favipiravir was recognized as an influenza antiviral drug in Japan in 2014,and has been known to have a potential in vitro activity against SARS-CoV-2,in addition to its broad therapeutic safety *** was recently approved and officially used in many countries *** review provides insights and up-to-date knowledge of the current role of favipiravir in the treatment of COVID-19 infection,focusing on preclinical and ongoing clinical trials,evidence of its efficacy against SARS-CoV-2 in COVID-19,side effects,anti-viral mechanism,and the pharmacokinetic properties of the drug in the treatment of *** to its teratogenic effects,favipiravir cannot be offered to expectant or pregnant *** practical efficacy of such an intervention regimen will depend on its dose,treatment duration,and cost as well as difficulties in application.

关键词： Favipiravir Avigan COVID-19 SARS-CoV-2 Antiviral Review Efficacy

Improving the Dispersion and Integration of Multi-Walled Carbon Nanotubes in PolyvinyI-Alcohol Composite Thin Film through Surface Modification

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Journal of Chemistry and Chemical Engineering 2013年第1期7卷 18-25页

作者： Van thang LE T. Mirth Nguyet NGUYEN Duy Vinh CAO Key Laboratory of Materials Technology Vietnam National University Ho Chi Minh City 70000 Vietnam Faculty of Materials Technology University of Technology Ho Chi Minh City 70000 Vietnam

The article investigated the influence of modification process parameters on dispersity of MWNTs DI （in deionized） water and PVA/MWNT composite＇s electrical conductivity. Experimental results obtained by SEM （scanning electron microscope）, TEM （transmission electron microscope）, transform Fourier infrared spectroscopy, pH meter confirmed the most effective conditions in modifying the MWNT surface at the 1：3 mixture of nitric and sulfuric acid at 60 ℃. The extinction coefficient value of functionalized MWNTs at 500 nm wavelength was determined to be 41.24 cm^2·mg^-1, while their dispersibility in DI water was about 12.85 mg/mL and stable in more than 3 weeks via UV-vis spectroscopy. The other important result is the decrease of volume resistivity from 7.98 × 10^6 MΩ·m ofPVA （polyvinyl alcohol） to 4.15 × 10^4 MΩ·m of PVA/1 wt% modified MWNT thin film.

关键词： MWNT modification composite