On 12 May 2026, at VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher Lê Thị Nga successfully defended a doctoral thesis in Microbiology. The research, titled “The prevalence of antibiotic resistance and characteristics of colistin resistance in enteric bacteria isolated from faecal samples of paediatric patients with diarrhoea in Southern Viet Namâ€�, was supervised by Associate Professor Phan Thị Phượng Trang and Dr Hoàng Hoài PhÆ°Æ¡ng.

Antimicrobial resistance represents one of the pre-eminent challenges to global public health, particularly regarding the clinical management of infections caused by multi-drug resistant Gram-negative bacteria. Consequently, colistin—a polymyxin antibiotic—serves as a treatment of last resort for numerous severe infections. Nevertheless, the emergence and dissemination of colistin resistance genes within the mcr family pose significant hurdles to therapeutic efficacy.

Driven by these clinical realities, the thesis investigates the status of antibiotic resistance and the specific mechanisms of colistin resistance in enteric bacteria isolated from paediatric patients aged five and under suffering from diarrhoea in Southern Viet Nam. The study involved isolating Enterobacteriaceae strains, performing antibiotic susceptibility testing, determining minimum inhibitory concentrations (MIC) for colistin, and identifying mcr genes via PCR techniques.

The findings indicate variations in colistin resistance rates across different groups of enteric bacteria, with E. coli and Klebsiella spp. exhibiting the highest prevalence. Furthermore, the research identified mcr-1, mcr-8, and mcr-9 gene variants within the isolates, providing clarity on the transmission dynamics of colistin resistance genes within microbial populations.

In addition, the thesis analysed the molecular genetic characteristics of mcr genes and evaluated the capacity for horizontal gene transfer through conjugation experiments. These results contribute essential data towards the establishment of a molecular surveillance system for colistin resistance genes in Viet Nam, specifically targeting children under five—a demographic characterised by immature immune systems and developing gut microbiota.

During the doctoral candidature, doctoral researcher Lê Thị Nga published three international papers indexed in Scopus and one national scientific paper presented at the National Conference on Biology.

The examiners commended the thesis for timeliness, scientific rigour, and originality. This work provides vital data to inform the ongoing study and monitoring of antibiotic resistance in paediatric enteric bacteria within the Vietnamese context.

 

On 11 May 2026, at VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher Lê Thanh Bình successfully defended a doctoral thesis in Microbiology. The research, entitled “Isolation, Selection, and Genetic Characterisation of Microorganism Strains from the Mekong Delta Capable of Antagonising Ralstonia solanacearum causing Bacterial Wilt in Cucumbers (Cucumis sativus)â€�, was conducted under the supervision of Associate Professor Phan Thị Phượng Trang and Dr Võ Ä�ình Quang.

The research focuses on selecting microbial strains capable of antagonising the bacterium Ralstonia solanacearum. This pathogen causes bacterial wilt in cucumbers, a disease that significantly impacts yields and cultivation efficiency across numerous vegetable-growing regions in the Mekong Delta.

By isolating and screening soil and disease samples collected throughout the Mekong Delta, the study identified several promising microbial strains. Notably, two strains—Bacillus velezensis DB2.1 and Streptomyces noursei DS30.6—demonstrated outstanding antagonistic efficacy within laboratory, greenhouse, and field settings.

Experimental results indicate that the combination of these two microbial strains substantially reduces the incidence of bacterial wilt in cucumber plants while simultaneously enhancing crop productivity. Furthermore, the study performed an analysis of genetic characteristics and functional genes related to the pathogenicity of the bacteria, alongside the antagonistic mechanisms of the selected microbial strains.

According to the findings, the thesis highlights the potential for utilising indigenous microbial strains to develop biological products for sustainable agriculture. Such advancements contribute to reducing the reliance on chemical pesticides in farming practices.

Throughout the doctoral candidacy, doctoral researcher Lê Thanh Bình published six scientific papers, comprising three articles in domestic journals and three international publications indexed in Scopus.

The Examination Committee concluded that the thesis satisfies all requirements for a doctorate in Microbiology, possessing both scientific merit and practical significance for the field of applied microbiology in agriculture.

 

On 28 March 2026, at VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher Lê Quang TrÆ°á»�ng (class of 2022) successfully defended a doctoral thesis at the institutional level in Algebra and Number Theory. The research is entitled: “Certain matrix decompositions corresponding to given generating setsâ€�.

The thesis was conducted under the academic supervision of Professor Mai Hoàng Biên and Dr Phạm Thị Thu Thủy. The study focuses on investigating matrix decomposition problems within linear groups, particularly describing subgroups generated by specific classes of elements, such as idempotent matrices of index 2, quadratic matrices, matrices of finite order, and commutators.

The scope of the research involves examining the structure of groups such as general linear groups, upper triangular matrix groups, and several classes of extended linear groups. Furthermore, the researcher investigated the representability of elements as products of elements from corresponding generating sets. A significant direction of the thesis is the determination of conditions under which a matrix can be decomposed into prescribed forms, alongside an evaluation of the decomposition length in each specific case.

Regarding the results, the thesis established necessary and sufficient conditions for representing matrices as products of element classes, including idempotent matrices of index 2, quadratic matrices, matrices of finite order, and commutators within specific algebraic classes. Additionally, the research contributes to clarifying the structure of certain subgroups within linear groups and the relationship between decomposition forms and the algebraic properties of matrices.

The findings of the thesis contribute to the supplement and development of research directions concerning linear group structures as well as matrix decomposition problems in non-commutative algebra.

The Examination Committee evaluated the thesis as being of high quality, possessing significant scientific merit and professional value within the fields of Algebra and Number Theory. The work was meticulously executed with a systematic approach, yielding numerous original results that do not duplicate previously published studies or research directions. The Committee further acknowledged that the researcher possesses strong independent research capabilities, demonstrated through international scientific publications directly related to the thesis content, fully satisfying the requirements for a doctoral degree.

 

On 28 March 2026, at VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher Trần Nam SÆ¡n (class of 2022, specialising in Algebra and Number Theory) successfully defended a doctoral thesis at the institutional level. The research is entitled: “Images of polynomials on certain classes of algebrasâ€�.

The thesis was conducted under the academic supervision of Professor Mai Hoàng Biên. The study focuses on investigating the images of polynomials when evaluated on non-commutative algebras, with a particular emphasis on generalised non-commutative polynomials and the connection to the L’vov–Kaplansky Conjecture and the Mesyan Conjecture.

The scope of the research involves examining the behaviour of polynomials across various classes of algebras, such as division algebras, matrix algebras over division rings, quaternion algebras, and other specialised algebraic structures. On this basis, the thesis considers instances where the image of a polynomial may cover the entire algebra or form characteristic subspaces.

Furthermore, the research investigates the representation of elements as products of squares or multiplicative commutators. These findings contribute to establishing links with problems in linear group theory and Waring-type problems within a non-commutative context.

Regarding the results, the thesis established necessary and sufficient conditions concerning algebraic structures through the images of polynomials. The researcher successfully described the images of multilinear polynomials on quaternion algebras and clarified specific cases where the polynomial image coincides with the entire algebra. Additionally, the study proved extended results related to Kursov’s Theorem and analysed the relationship between multiplicative commutators and squares in several classes of algebras.

The Examination Committee evaluated the thesis as being of high quality, possessing significant scientific merit and professional value within the fields of Algebra and Number Theory. The researcher demonstrated a capacity for independent research, fully satisfying the requirements for a doctoral thesis. The findings are reliable, original, and do not duplicate previously published works, thereby contributing to the clarification of advanced problems within the field of study.

On 24 March, at VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher Ä�á»— Văn Nhật TrÆ°á»�ng successfully defended a doctoral thesis at the institutional level in Organic Chemistry. The research is entitled: “Study on the chemical constituents, xanthine oxidase inhibitory activity, and anti-inflammatory activity of Gnetum montanum Markgr.â€�, conducted under the academic supervision of Professor Nguyá»…n Thị Thanh Mai.

The work focuses on investigating the chemical composition and biological activity of the G. montanum species in Viet Nam, thereby adding scientific data to this medicinal material and providing a basis for applied research orientations in the field of healthcare.

From the screening process of 22 methanol (MeOH) extract samples from 18 medicinal plant species according to the ability to inhibit the xanthine oxidase (XO) enzyme—an enzyme related to the formation of uric acid in gout—the project recorded 12 samples with good activity (IC₅₀ < 100 µg/mL). Among these, the extract sample from the G. montanum stem showed outstanding results with an IC₅₀ value of 76.7 µg/mL. On this basis, the researcher selected the stem of this species for further in-depth investigation.

One of the prominent results is the successful isolation and structural identification of 47 compounds from the EtOAc extract of the G. montanum stem. Notably, the research group published 11 new compounds discovered for the first time, including 7 compounds belonging to the stilbene group, 2 2-phenylbenzofuran compounds, 1 lignan compound, and 1 phenolic acid glycoside compound. Simultaneously, this is also the first time two groups of compounds, anthraquinone and cycloartane triterpene, have been recorded in this species.

In addition to clarifying the chemical composition, the work also evaluates the biological activity of the extracts and compounds isolated from G. montanum. The results show that the test samples exhibit remarkable XO enzyme inhibition and anti-inflammatory capacity, whilst showing no toxicity to RAW264.7 cells at the tested concentrations.

Specifically, the EtOAc extract showed the strongest XO inhibition with an IC₅₀ value of 25.3 µg/mL. At the molecular level, 10 compounds exhibited XO inhibitory activity and 19 compounds showed anti-inflammatory activity (inhibition of NO production) with IC₅₀ values < 100 µM. Among these, 6 newly isolated compounds showed good XO inhibitory effects; whereas in the anti-inflammatory test, stilbene framework compounds recorded outstanding results, typically isorhapontigenin with an IC₅₀ value of 5.9 µM, which is superior to the positive control quercetin (14.0 µM).

Another noteworthy point is the optimisation of the isolation process for two highly active compounds: resveratrol (5.0 g) and isorhapontigenin (50.0 g). On this basis, the researcher successfully established reference standards for these two compounds with purities reaching 99.14% and 96.38% respectively. This result contributes to the quantification of the main compounds, aiming at quality control for medicinal materials and products derived from G. montanum in the future.

The Examination Committee acknowledged the serious research effort, the large volume of work, and the scientific and practical value of the project. The achieved results not only supplement data on the phytochemistry and biological activity of G. montanum in Viet Nam, but also contribute to clarifying the potential of this species in the development of herbal products.

On 20 March 2026, at VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher VÅ© Tấn Phát successfully defended a doctoral thesis at the institutional level in Physical and Theoretical Chemistry. The research is entitled: “Study on the synthesis and electrochemical characterisation of silica-based materials for use as negative electrodes in Lithium-ion and Sodium-ion rechargeable batteriesâ€�, conducted under the academic supervision of Associate Professor Trần Văn Mẫn and Associate Professor Lê Mỹ Loan Phụng.

The thesis focuses on the development of SiO₂-based materials for negative electrodes in Li-ion and Na-ion rechargeable batteries, aiming to overcome limitations such as low electrical conductivity, significant volume expansion, and the poor stability of the Solid Electrolyte Interphase (SEI) layer. On this basis, the researcher successfully synthesised C/SiO₂ material from rice husk biomass using chemical activation methods, creating a porous, low-cost, and environmentally friendly structure. Modifying the material with graphene and silver nanoparticles (AgNPs) facilitated the formation of a continuous conductive network, significantly improving ion diffusion and electrochemical performance.

Research results indicate that the materials achieve high capacity, stable Coulombic efficiency exceeding 98%, and excellent rate capability. Simultaneously, the electrolyte system was optimised with LiPF₆ salt and FEC additives for high electrochemical stability, contributing to enhanced battery performance. These materials were subsequently utilised to assemble full-cells and pouch cells, demonstrating stable operation and good capacity retention over numerous charge-discharge cycles, thus proving the potential for practical application.

Furthermore, the thesis investigated a novel material, Mn₇O₈SiO₄, featuring a stable structure and superior ion storage capacity, opening avenues for the development of next-generation electrode material systems. These findings not only contribute to enhancing the efficiency of SiO_{2 Â} materials but also move towards the development of sustainable energy storage solutions by utilising biomass sources and promoting a circular economy.

The Examination Committee highly commended doctoral researcher Vũ Tấn Phát for the scientific value and practical applicability of the thesis, noting that the doctoral researcher exceeded all doctoral education requirements. During the research process, the doctoral researcher published 11 scientific works, including 9 international publications (7 as lead author), 1 domestic journal article, and 1 patent, confirming outstanding research capacity and academic contribution. The results achieved by the thesis provide a further scientific foundation for the development of silica-based electrode materials, whilst offering prospects for application in next-generation rechargeable battery systems, aligning with global trends in green and sustainable energy development.

On the afternoon of 20 March 2026, at VNUHCM–Â鶹´«Ã½ (HCMUS), researcher Ä�oàn Thiên Thanh (Biotechnology, class of 2017) successfully defended a doctoral thesis at the institutional level. The research is entitled: “Study on the activity and mechanism of action against Helicobacter pylori of extracts and compounds from hexane fractions of Cleistocalyx operculatus (Roxb.) Merr. et Perry (synonym Syzygium nervosum) leaves and flower budsâ€�.

The thesis was conducted under the academic supervision of Senior Lecturer Dr Lương Thị Mỹ Ngân and Senior Lecturer Dr Trần Trung Hiếu. The study focuses on harnessing the medicinal potential of Cleistocalyx operculatus—a species familiar in daily life with significant value in traditional medicine, though the biological mechanisms of the species remain insufficiently researched.

The scope of the research involved the collection of total extracts and fractional extracts from the leaves and flower buds of C. operculatus, alongside the qualitative and quantitative analysis of natural compounds present within these extracts. On this basis, the thesis evaluated the anti-Helicobacter pylori activity and the in vitro urease enzyme inhibition capacity. The hexane fraction from flower buds was selected for further isolation and identification of primary bioactive compounds. Furthermore, the study analysed the mechanisms by which the extracts and compounds affect biofilm formation, cellular integrity, and morphology, as well as the expression levels of bacterial virulence genes.

The research findings yielded 14 total extracts and 6 fractional extracts from the leaves and flower buds. These fractional extracts demonstrated higher concentrations of natural compounds—specifically phenols and flavonoids—compared to the total extracts. Hexane fractions exhibited marked inhibitory activity against H. pylori, with Minimum Inhibitory Concentrations (MIC) ranging from 62.5 to 125 µg/mL, whilst effectively inhibiting the urease enzyme. From the hexane fraction of the flower buds, the study isolated and identified three representative compounds: DMC, kaempferol, and β-sitosterol, with DMC and kaempferol showing prominent anti-H. pylori activity.

These compounds not only inhibit bacterial growth but also influence several critical biological mechanisms. Such actions include the suppression of biofilm formation, increasing membrane permeability, and disrupting cell membrane structure. There was also a significant reduction in the expression of virulence genes, namely cagA, vacA, ureA, ureB, flaA, flaB, flgE, and dnaA. Toxicity assessments indicated a high level of safety on normal cells, suggesting significant potential for application within the biomedical field.

From the achieved results, the thesis provides further scientific evidence regarding the medicinal value of C. operculatus in the prevention and supportive treatment of gastric diseases related to Helicobacter pylori. This approach, utilising natural compounds, is regarded as a promising pathway to reduce reliance on antibiotics and contribute to mitigating the rise of drug resistance.

The Board commended the thesis for the systematic approach, clear data, and reliability. The findings hold scientific value and provide a significant reference for future research in medicinal plants and microbiology.

On 12 March 2026, at the VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher Lê Ngá»�c Năng (2023–2026 cohort) successfully defended his doctoral dissertation at the institutional level. The research, titled “Mineralogical, Gemmological Characteristics and Origin of Gemstones Associated with Basalts in Southeast Viet Nam,â€� was conducted under the academic supervision of Associate Professor Phạm Trung Hiếu.

The dissertation focuses on the mineralogical and gemmological properties, as well as the origins, of various gemstones associated with Cenozoic basalt formations widely distributed across Southeast Viet Nam. By integrating geological, petrological, and geochemical methodologies with advanced gemmological and spectroscopic analytical techniques, the study identified seven types of minerals suitable for use as gemstones: sapphire, zircon, pyrope (garnet), anorthoclase (alkali feldspar), augite, brown peridot, and opal.

Findings indicate that gemstones within this region generally exhibit mineralogical and gemmological characteristics consistent with global records. Nevertheless, several notable distinctions were identified, contributing new scientific data and refining the criteria for the identification and quality assessment of basalt-related gemstones in Viet Nam.

Geochemical analysis and geological evidence suggest that the majority of these gem minerals did not crystallise directly from basaltic magma (with the exception of opal). Instead, the basalt primarily served as a medium for transporting and hosting minerals that had previously formed from diverse sources, such as syenite, peridotite, or deep-seated magmas. This discovery clarifies the mechanisms underlying the formation and distribution of basalt-associated gemstones in the Southeast region.

Gemmological quality assessments revealed that the zircon, pyrope, anorthoclase, and augite samples are of high quality, whereas the sapphire, brown peridot, and opal range from medium to low quality. Although the potential for commercial extraction remains uncertain at present, these gemstones possess significant scientific value. Furthermore, the study highlights prospective opportunities for exploitation through geo-heritage and geo-tourism in the future.

Throughout the doctoral programme, doctoral researcher Lê Ng�c Năng published seven scientific papers in prestigious national and international journals, demonstrating rigorous academic discipline and a profound research capacity within the fields of geology and gemmology.

Based on the successful defence and established academic criteria, the Committee resolved to confer the degree of Doctor of Philosophy in Geology upon doctoral researcher Lê Ng�c Năng.

Image credit: Office of Graduate Studies

 

On 1 March 2026, at VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher Mai Văn Duy successfully defended a doctoral dissertation in Applied Mathematics. The thesis, entitled “Optimality conditions and duality for some classes of adjustable robust optimisation problems”, was conducted under the academic supervision of Associate Professor Nguyá»…n Minh Tùng and Associate Professor Nguyá»…n Lê Hoàng Anh.

The research focuses on optimality conditions and duality models for several classes of adjustable robust optimisation problems. These include adjustable robust linear, convex, non-smooth, and multi-objective convex optimisation. Central to this study is the construction of non-adjustable equivalent forms for adjustable robust optimisation problems involving general data.

By establishing these equivalent forms, the adjustable robust optimisation problem is transformed into a standard robust optimisation model—a framework extensively studied within optimisation theory, supported by a wealth of analytical tools and algorithms. This approach simplifies the structure of the original problem and facilitates the application of established techniques within the field of robust optimisation.

The equivalent models were developed within a comprehensive framework sufficiently broad to encompass most classes of adjustable robust optimisation problems, including linear, convex, and non-smooth cases. Notably, the proposed methodology does not require restrictive assumptions regarding the structure of the uncertainty set, thereby extending the applicability of these models to complex real-world scenarios.

Building upon this foundation, the thesis employs tools from robust optimisation and variational analysis to systematically investigate regularity conditions and constraint qualifications. The work establishes optimality conditions for various types of solutions in adjustable robust multi-objective problems and analyses the corresponding duality models. These findings offer novel contributions that supplement and advance previous research on adjustable robust optimisation, strengthening the theoretical framework and providing a basis for future algorithmic developments.

Beyond the theoretical significance, the results provide a foundation for analysing computational complexity and developing efficient solution methods for optimisation problems under uncertainty.

Throughout the doctoral candidacy, doctoral researcher Mai Văn Duy published four international scientific papers related to the dissertation within the ISI/Scopus database. These publications comprise two Q1, one Q2, and one Q3 ranked journals, with a cumulative Impact Factor of 5.7.

The Examination Committee concluded that the dissertation fully satisfies the requirements for a doctorate in Applied Mathematics. The research holds significant scientific value and serves as a formal reference for advanced study and specialised research within the field.

On 1 March 2026, at VNUHCM–Â鶹´«Ã½ (HCMUS), doctoral researcher Hoàng Văn Ä�ại (2022 cohort, Mathematical Analysis) successfully defended a doctoral thesis entitled “Investigation of Several Non-local Problems Involving Fractional Derivativesâ€�. The research was conducted under the academic supervision of Assoc. Prof. Nguyá»…n Huy Tuấn and Assoc. Prof. Bùi Lê Trá»�ng Thanh.

During the presentation, the researcher elucidated three primary groups of problems within the field of partial differential equations: non-local problems with Riemann–Liouville derivatives; problems utilising modified Caputo derivatives; and fractional Rayleigh–Stokes equations featuring exponential nonlinear source terms. Built upon a systematically constructed theoretical framework, the thesis establishes conditions ensuring the existence, uniqueness, and stability of solutions, whilst further analysing ill-posed scenarios frequently arising in models with non-local elements.

To address specific challenges inherent in these problems, the research employs a versatile range of modern analytical tools, including the concept of mild solutions, fixed-point theorems, Sobolev embeddings, spectral analysis, and fundamental inequalities. Such an approach facilitates an extension of the scope of investigation for classes of equations with more complex structures than previously published results.

Notable contributions of the thesis include: establishing a theoretical framework for problems involving various forms of fractional derivatives; proposing methods to handle ill-posed problems via the concept of mild solutions; and providing supplementary research findings on fractional Rayleigh–Stokes equations with exponential nonlinear sources—a field hitherto seldom explored domestically. These results contribute to the refinement of the theoretical foundations for models characterised by memory effects and non-local interactions.

Regarding practical applications, the findings may assist in modelling physical and engineering phenomena such as anomalous diffusion, the motion of viscous fluids, heat transfer in specialised materials, and certain financial models. Furthermore, the thesis suggests potential for developing discretisation methods and numerical algorithms for simulation-based research in computational science. This work also serves as an advanced reference for teaching and future research directions in the field of fractional partial differential equations.

In addition to the achieved results, the researcher proposed future developments, such as extending the models to more complex nonlinear structures, considering alternative definitions of fractional derivatives, and constructing efficient numerical methods to optimise computational costs and enhance interdisciplinary applicability.

Concluding the session, the Examination Committee determined that the thesis satisfies all requirements for a doctoral degree under current regulations and unanimously approved the work. The thesis was judged to meet the required standards, possessing significant reference value for both specialist training and academic research.