A novel tertiary magnetic ZnFe2O4/BiOBr/rGO nanocomposite catalyst for photodegrading organic contaminants by visible light.

A novel tertiary magnetic ZnFe2O4/BiOBr/rGO visible light-driven photocatalytic system was successfully synthesized from graphite, bismuth nitrate pentahydrate, iron (III) nitrate, and zinc nitrate precursors. The produced materials were characterized regarding micro-structure, chemical composition and functional groups, surface charge properties, photocatalytic characteristics such as band gap energy (Eg), recombination rate of charge carriers, and magnetic properties. ZnFe2O4/BiOBr/rGO heterojunction photocatalyst exhibited a saturation magnetization of 7.5 emu/g, and a visible light response (Eg = 2.08 eV). Thus, under visible light, these materials could generate effective charge carriers responsible for forming free hydroxyl radicals (HO•) for degrading organic pollutants. ZnFe2O4/BiOBr/rGO also exhibited the lowest charge carriers recombination rate compared to all individual components. The construction of ZnFe2O4/BiOBr/rGO system resulted in 1.35 to 2.55 times higher in photocatalytic degradation of DB 71 compared to individual components. At the optimal conditions (0.5 g/L catalyst load and pH 7.0), the ZnFe2O4/BiOBr/rGO system could completely degrade 30 mg/L DB 71 after 100 min. DB 71 degradation process was best described by the pseudo-first-order model, with the coefficient of determination within the range of 0.9043-0.9946 for all conditions. HO• radicals were mainly responsible for degrading the pollutant. The photocatalytic system could be effortlessly regenerated, very stable, which showed an efficiency of >80.0 % after 5 repetitive runs regarding the DB 71 photodegradation. The photocatalyst was easily recovered by a magnet. This research provides a novel approach for producing an effective and practical photocatalyst that can be applied in real organic pollutants-containing waste water treatment systems.

Aetiology of Acute Undifferentiated Fever Among Children Under the Age of Five in Vietnam: A Prospective Study.

BACKGROUND: To investigate the aetiology of acute undifferentiated fever (AUF) among children under the age of five in Vietnam. METHODS: This prospective study was conducted in the Thai Binh paediatric hospital, between July 2020 and July 2021 among children with AUF at admission. Real-time PCR testing 18 microbial pathogens were done on blood samples. RESULTS: 286 children were included, with median age of 16 months. 64.7% were male. 53.9% were positive for at least one pathogen by PCR. Enterovirus, human herpesvirus 6, adenovirus, and varicella zoster virus PCR were positive for 31.1, 12.6, 1.4, and 1.0% patients, respectively. Other pathogens tested negative by PCR. During the hospital stay, based on clinical criteria 47.2% children secondarily presented with signs of respiratory tract infections, 18.9% had hand, foot and mouth disease, 4.6% had chickenpox. 4.2% presented signs of central nervous system infections, 1.0% had dengue (antigenic test) and 1.0% had signs of gastrointestinal infection. Finally, 23.1% patients presented a fever with or without a rash and no other symptoms and ultimately received a diagnosis of AUF. CONCLUSION: Real-time PCR of blood is useful for detecting pathogens and diagnosing infectious causes of AUF. Further prospective studies with blood and urine culture testing and PCR investigation of not only blood but also cerebrospinal fluid, throat, and skin samples according to symptoms would be of interest to confirm the predominance of viral infections in children with AUF and to guide therapeutic options.

Novel N,C,S-TiO2/WO3/rGO Z-scheme heterojunction with enhanced visible-light driven photocatalytic performance.

Novel N,C,S-TiO2/WO3/rGO Z scheme photocatalyst was successfully synthesized from graphite, TIOT, and ammonium metatungstate precursors. Material characteristics such as crystal structure, surface morphology, functional groups, specific surface area, elemental composition, band gap energy, and electron-hole recombination were characterized by XRD, TEM, BET, SEM/EDX, FT-IR, UV-VIS, and PL methods. The as-synthesized novel N,C,S-TiO2/WO3/rGO Z-scheme heterojunction photocatalyst exhibited visible light-driven photocatalytic activity (the band gap energy = 2.24 eV), could generate both effective electrons and holes, and presented the lowest electron-hole recombination rate compared to all individual components. Different factors impacting the photocatalytic decomposition of Direct Blue 71 (DB 71) by the N,C,S-TiO2/WO3/rGO system were studied. The results showed that pH of the solution, catalyst load, DB 71 initial concentration, and reaction time affected the DB 71 photocatalytic degradation efficiency. The DB 71 degradation completed after 100 min with a typical efficiency of over 91%, which was much better than other photocatalytic systems. The DB 71 degradation process followed the pseudo-first-order kinetics model with coefficients of determination > 0.95 for all conditions. The photocatalyst was easily regenerated, and exhibited a very good stability, with a photocatalytic degradation efficiency of over 83.0% after 3 cycles.

Peak shape enhancement using diethylamine in hydrophilic liquid interaction chromatography: Application in simultaneous determination of methionine and paracetamol.

Methionine (MET) is combined with paracetamol (PAR) in a pain relief soft capsule in order to prevent the haematologic damage of paracetamol. A hydrophillic liquid chromatographic (HILIC) method was developed for simultaneous determination of PAR and MET in the combined formulation. Various analytical conditions were investigated, and the final method was chosen using silica column (150 × 4,6 mm; 5 µm), mobile phase of acetonitrile - aqueous solution of 10 mM formic acid 5 mM diethylamine (60:40, v/v), UV detection at 254 nm for PAR and 210 nm for MET. The method was validated according to ICH guidelines in terms of selectivity, linearity, accuracy, precision and robustness. The method was successfully applied for quantitation of both compounds in soft capsule preparations bought from the market. Notably, in this study, a novel approach was proposed to improve peak shape of amino acid - a problem often observed in HILIC. The addition of diethylamine to mobile phase shortened the retention time of MET and significantly improved peak shape on both silica and cyano columns, due to electrostatic interaction competition and silanol end-capping effect. The result of this research demonstrated the advantages of HILIC in simultaneous analysis of a polar compound amino acid, especially in combination with a less polar substance. The use of diethylamine as a mobile phase modifier to enhance peak shape is a new suggestion that can be used in further studies on amino acid analysis by HILIC.

Phytochemical profile of Syzygium formosum (Wall.) Masam leaves using HPLC-PDA-MS/MS and a simple HPLC-ELSD method for quality control.

Syzygium formosum (SF) leaves have been used for thousands of years in traditional Vietnamese medicine for the treatment of allergy or skin rash. However, the role of the phytochemical profile of SF leaves on their activities is poorly understood. Additionally, there is currently no quality control method for this herbal material, which is required by the pharmaceutical industry. Therefore, this study aimed to investigate chemical profile of SF leaves using high-performance liquid chromatography-photodiode array-tandem mass spectrometry (HPLC-PDA-ESI-MS/MS) and establish a simple and efficient HPLC method for controlling major bioactive compounds. The characterization of 28 components, including eleven flavonoids, thirteen triterpene acids, and four phenolic acids, was achieved on the basis of their maximum ultraviolet wavelength values and MS fragmentation pathways. An HPLC-evaporate light scattering detector (HPLC-ELSD) method over 35 min of analysis time for quality control of SF leaves was proposed. Using response surface methodology based on a Box-Behnken design and Derringer's desirability function, the optimal conditions for extracting the main bioactive compounds in SF leaves were determined. The content of marker compounds within SF leaves decreased in the order asiatic acid > corosolic acid > betulinic acid > maslinic acid. The developed HPLC-ELSD method is appropriate for quality control testing of SF leaves.

Evaluation of phenolic compounds from viroid-free and viroid-infected apples using HPLC-PDA-ESI-MS/MS.

INTRODUCTION: Apples are the most consumed fruits in Korea and have played an economically important role in Korean agriculture. However, widespread viroid infection in apples had been reported in recent years. OBJECTIVES: The objective of this study was to clarify the relationships between viroid-disease resistance and phenols content of three apple cultivars: "Fuji", "Gamhong", and "Hongro". A model for distinguishing between viroid-free and viroid-infected apples was also developed. METHODOLOGY: Phenolic compounds in samples were detected using high-performance liquid chromatography photodiode array tandem mass spectrometry (HPLC-PDA-MS/MS) and quantified using an ultraviolet detector at 280 nm. A C18 -column and 0.5% aqueous acetic acid-methanol were used as the stationary and mobile phase. The HPLC method was validated with respect to linearity, precision, accuracy, and recovery. Multivariate analysis was performed using phenols content as variables to classify viroid-free and viroid-infected apples. RESULTS: An accurate method for identifying and quantifying phenol compounds in apple samples was developed and validated. In response to viroid infection, considerable increases in the content of dihydrochalcones (in all three cultivars), hydroxycinnamic acid (in "Fuji"), and flavonols (in "Hongro") were observed. The flavonols content in "Fuji" viroid-infected samples, however, decreased dramatically. An effective linear discriminant model, with 98.2% accuracy and 94.6% predictive ability, was achieved to discriminate between viroid-free and viroid-infected samples. CONCLUSION: The developed HPLC method is suitable to identify and quantify phenol compounds in viroid-free and viroid-infected apples. A hypothesis about the significance of these compounds in viroid-disease resistance was proposed. The linear discriminant model with high predictive ability is useful for identifying viroid-infected apples in the orchards.

Growth in children infected with HIV receiving anti-retroviral therapy in Vietnam.

BACKGROUND: There are currently two markers used to monitor treatment response to anti-retroviral therapy (ART) in HIV-infected children: CD4 T-cell count and HIV viral load; but analysis of these could be challenging in resource-poor countries. The aim of this study was therefore to determine whether change in growth parameters such as weight-for-age Z score (WAZ), height-for-age Z score (HAZ) and body mass index-for-age Z score (BMIZ) is associated with treatment response in HIV-infected children. METHODS: This was a nested case-control study, in which the data were collected at enrolment and then periodically every 6 months for a total 36 month follow up of 107 HIV-infected children enrolled and treated at National Hospital of Pediatrics, Vietnam. RESULTS: At treatment initiation, WAZ, HAZ and BMIZ were not significantly higher in the treatment success (TS) group compared with the treatment failure (TF) group. After ART initiation, WAZ and HAZ increased, and this was significant in the TS group (from -1.5 to -0.54, P < 0.01 and from -2.06 to -0.84, P < 0.01, respectively). Low HAZ was significantly associated with TF (HR, 0.71; 95% CI: 0.54-0.92). CONCLUSION: Height-for-age Z score was the most sensitive growth parameter in prediction of the treatment response. In order to use growth parameters, particularly HAZ as a prognosis marker for TF in clinical practice, further research should be conducted to evaluate the role of growth parameters and their effects on treatment response.

Elevation of immunoglobulin levels is associated with treatment failure in HIV-infected children in Vietnam.

BACKGROUND: HIV-infected children suffer from higher levels of treatment failure compared to adults. Immunoactivation, including humoral immunoactivation reflected by increased immunoglobulin levels, is believed to occur early during HIV infection. Therefore, we wanted investigate alteration in immunoglobulin levels in association with treatment response in HIV-infected children. METHODS: A nested case-control study was conducted using clinical data collected from 68 HIV-infected children enrolled at the National Hospital of Pediatrics, Vietnam. RESULTS: The results showed that immunoglobulin levels, CD4 T-cell counts, CD4 T-cell percentage, and HIV load were significantly higher in the treatment-failure group than the treatment-success group at treatment initiation. IgG and IgA levels were negatively correlated with CD4 T-cell counts (P=0.049 and P<0.01, respectively) and positively correlated with HIV load (P=0.04 and P=0.02, respectively). In addition, IgG and IgA levels were independently associated with treatment response, analyzed by Cox regression analysis (HR 1.19 [P=0.049] and HR 1.69 [P<0.01], respectively). CONCLUSION: Elevation of IgA levels occurred early during HIV infection, and might have a prognostic role in treatment response.

Adjunctive dexamethasone for the treatment of HIV-uninfected adults with tuberculous meningitis stratified by Leukotriene A4 hydrolase genotype (LAST ACT): Study protocol for a randomised double blind placebo controlled non-inferiority trial.

Background: Tuberculosis kills more people than any other bacterial infection worldwide. In tuberculous meningitis (TBM), a common functional promoter variant (C/T transition) in the gene encoding leukotriene A4 hydrolase (LTA4H), predicts pre-treatment inflammatory phenotype and response to dexamethasone in HIV-uninfected individuals. The primary aim of this study is to determine whether LTA4H genotype determines benefit or harm from adjunctive dexamethasone in HIV-uninfected Vietnamese adults with TBM. The secondary aim is to investigate alternative management strategies in individuals who develop drug induced liver injury (DILI) that will enable the safe continuation of rifampicin and isoniazid therapy.  Methods: We will perform a parallel group, randomised (1:1), double blind, placebo-controlled,  multi-centre Phase III non-inferiority trial, comparing dexamethasone versus placebo for 6-8 weeks in addition to standard anti-tuberculosis treatment in HIV-uninfected patients with TBM stratified by LTA4H genotype. The primary endpoint will be death or new neurological event. The trial will enrol approximately 720 HIV-uninfected adults with a clinical diagnosis of TBM, from two hospitals in Ho Chi Minh City, Vietnam. 640 participants with CC or CT- LTA4H genotype will be randomised to either dexamethasone or placebo, and the remaining TT- genotype participants will be treated with standard-of-care dexamethasone. We will also perform a randomised comparison of three management strategies for anti-tuberculosis DILI. An identical ancillary study will also be perfomed in the linked randomised controlled trial of dexamethasone in HIV-infected adults with TBM (ACT HIV).  Discussion: Previous data have shown that LTA4H genotype may be a critical determinant of inflammation and consequently of adjunctive anti-inflammatory treatment response in TBM. We will stratify dexamethasone therapy according to LTA4H genotype in HIV-uninfected adults, which may indicate a role for targeted anti-inflammatory therapy according to variation in LTA4H C/T transition. A comparison of DILI management strategies may allow the safe continuation of rifampicin and isoniazid.

Anti-allergic effects of the ethanol extract of Syzygium formosum (Wall.) Masam leaves and its immunoregulatory mechanisms.

ETHNOPHARMACOLOGICAL RELEVANCE: As documented in a Vietnamese traditional medical encyclopedia, Syzygium formosum (Wall.) Masam leaves have been routinely used among indigenous Vietnamese people for treatment of various allergy-like symptoms including dermatitis and rhinitis. AIM OF THE STUDY: Anti-allergic activity of S. formosum leaves was examined with a mouse model of chicken ovalbumin (cOVA)-induced food allergy, and mechanisms underlying the anti-allergic effect were explored. MATERIAL AND METHODS: BALB/c mice were administered i.p. cOVA (20µg) plus alum (2mg) twice on day 0 and 14 for sensitization (immunization). Two weeks after the second immunization, the mice were administered cOVA (50mg) p.o. 5 times every 3 days to induce food allergy symptoms (i.e., anaphylaxis, diarrhea, and drop in the body temperature). Ethanol extract of dried leaves of S. formosum (80mg/kg or 200mg/kg body weight) was administered p.o. daily during the induction (challenge) period. RESULTS: Treatment with the S. formosum leaves ethanol extract ameliorated the allergic symptoms to a significant extent and in a dose-dependent manner. The treatment also resulted in a significant improvement in the inflammatory lesion in the small intestine and reduction in the numbers of mast cells and eosinophils recruited to the lesion. The treatment also brought about a significant reduction in the levels of Th2 cytokines produced by the mesenteric lymph node cells cultured ex vivo with cOVA. The passive anaphylaxis experiment also showed that the extract treatment impaired the mast cell function. CONCLUSION: Our study provides a scientific basis for the traditional (indigenous) use of the S. formosum leaves extract for the treatment of various allergy symptoms in Vietnam. In addition, the results show that the extract has activities to suppress antigen-specific Th2 T cell immune responses and the mast cell function, which are directly related with its anti-allergic effect.