Graphitic carbon nitride supported silver nanoparticles (AgNPs/g-C3N4): synthesis and photocatalytic behavior in the degradation of 2,4-dichlorophenoxyacetic acid.

Graphitic carbon nitride supported silver nanoparticles (AgNPs/g-C3N4) with 1%, 3%, and 5% AgNPs were successfully synthesized by an "ex situ" method with ultrasound of a mixture of AgNP solution and g-C3N4. The AgNP solution was prepared by chemical reduction with trisodium citrate, and g-C3N4 was synthesized from the urea precursor. The supported nanoparticles were characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption (BET), Fourier transformation infrared (FTIR) and Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence spectroscopy (PL), electron paramagnetic resonance (EPR) and electrochemical impedance spectroscopy (EIS) Nyquist plots. The visible light-driven photocurrent measurement was performed by three on-off cycles of intermittent irradiation. The analyses show that AgNPs were evenly dispersed on g-C3N4, and have sizes ranging from 40 to 50 nm. The optical properties of the AgNPs/g-C3N4 material were significantly enhanced due to the plasmonic effect of AgNPs. The photocatalytic activity of catalysts was evaluated by 2,4-D degradation under visible light irradiation (λ > 420 nm). In the reaction conditions: pH 2.2; C o (2,4-D) 40 ppm; a m/v ratio of 0.5 g L-1, AgNPs/g-C3N4 materials exhibit superior photocatalytic activity compared to the pristine g-C3N4. The studies on the influence of free radicals and photogenerated holes, h+, show that ˙OH, O2˙-, and h+ play decisive roles in the photocatalytic activity of AgNPs/g-C3N4. The TOC result indicates the minimal toxicity of the by-products formed during the 2,4-D degradation. In addition, the AgNPs/g-C3N4 catalytic activity under direct sunlight irradiation was similar to that under artificial UV irradiation. Based on these results, a possible mechanism is proposed to explain the enhanced photocatalytic activity and stability of AgNPs/g-C3N4. Theoretical calculations on the interaction between 2,4-D and g-C3N4, Ag/g-C3N4 was also performed. The calculated results show that the adsorption of 2,4-D on Ag-modified g-C3N4 is significantly more effective compared to pristine g-C3N4.

The Production of Standardized Samples with Known Concentrations for Severe Acute Respiratory Syndrome Coronavirus 2 RT-qPCR Testing Validation for Developing Countries in the Period of the Pandemic Era.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic of pneumonia spreading around the world, leading to serious threats to public health and attracting enormous attention. There is an urgent need for sensitive diagnostic testing implementation to control and manage SARS-CoV-2 in public health laboratories. The quantitative reverse transcription PCR (RT-qPCR) assay is the gold standard method, but the sensitivity and specificity of SARS-CoV-2 testing are dependent on a number of factors. METHODS: We synthesized RNA based on the genes published to estimate the concentration of inactivated virus samples in a biosafety level 3 laboratory. The limit of detection (LOD), linearity, accuracy, and precision were evaluated according to the bioanalytical method validation guidelines. RESULTS: We found that the LOD reached around 3 copies/reaction. Furthermore, intra-assay precision, accuracy, and linearity met the accepted criterion with an RSD for copies of less than 25%, and linear regression met the accepted R 2 of 0.98. CONCLUSIONS: We suggest that synthesized RNA based on the database of the NCBI gene bank for estimating the concentration of inactivated virus samples provides a potential opportunity for reliable testing to diagnose coronavirus disease 2019 (COVID-19) as well as limit the spread of the disease. This method may be relatively quick and inexpensive, and it may be useful for developing countries during the pandemic era. In the long term, it is also applicable for evaluation, verification, validation, and external quality assessment.

Comparison of Primer-Probe Sets among Different Master Mixes for Laboratory Screening of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).

BACKGROUND: There is a shortage of chemical reagents for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnosis and a surge of SARS-CoV-2 cases, especially in limited-resource settings. Therefore, the combination of an optimal assay kit is necessary. METHODS: We compared the ability to screen SARS-CoV-2 among three primer-probe sets in two different master mixes, Invitrogen™ SuperScript™ III One-Step RT-PCR and LightCycler Multiplex RNA Virus Master. RESULTS: The assay with TIB-Molbiol, IDT, and Phu Sa sets for LightCycler Multiplex RNA Virus Master or Invitrogen™ SuperScript™ III One-Step RT-PCR showed positive results from a single reaction of triplicate in the three days of 4.8 copies per reaction. R squared and amplification efficiency were 0.97 and ranged from 107 to 108%, respectively. CONCLUSIONS: Our findings indicated that TIB-Molbiol, IDT, and Phu Sa primer-probe sets could be beneficial for the laboratory screening of SARS-CoV-2 by RT-qPCR assay of E gene. There is a need to consider the combination of these reagent sets as a new strategy to increase the testing capacity of screening programs for COVID-19.

Assessing the Status of Filtering Blebs at 5 Year Post- Trabeculectomy.

BACKGROUND: Glaucoma is a common cause of blindness in the world as well as in Vietnam. It is treated by many different methods but trabeculectomy is still the most popular and highly effective surgical method to treat this condition. AIM: To analyze the status of 5 years filtering blebs following trabeculectomy and to explore multiple factors associated with filtering blebs. METHODS: This is a retrospective, cross-sectional descriptive study. Eyes had been performed trabeculectomy for 5 years were included in these results. The filtering blebs were assessed using slit lamp and OCT. the OCT captured bleb area to evaluate fluid subconjunctival spaces, thickness and height of bleb and to evaluate the related factors. RESULTS: A group of 106 primary glaucoma eyes of 97 patients (88 patients with 1 eye, 9 patients 2 eyes) had been performed trabeculectomy for 5 years were taken OCT anterior image. The proportion of female patients is 1.5 times that of male patients. IOP was controlled with or without topical medication in all eyes. The filtering bleb had a high echo reflection, which accounted for 42.5%, the average echo reflection was 38.6%, the low echo reflection response of 18.9%. 66% of the eyes had the aqueous space under the conjunctiva, 65.1% have the aqueous space under sclera flap, the average height of the bleb on OCT was 0.4 mm ± 0.3 mm. Young patients often have a higher rate of bleb fibrosis and loss of function than older patients. CONCLUSION: OCT is capable of assessing the function of bleb. After 5 years of trabeculectomy, on the OCT image, most cases of blebs are maintaining drainage function.

Association between salinity and hospital admission for hypertension: an ecological case-control study in the Mekong Delta Region in Vietnam.

Background: Drinking water in the Mekong Delta Region (MDR) is highly vulnerable to salinity intrusion and this problem is expected to increase with the projected climate change and sea level rise. Despite this, research on health effects of saline contaminated water is scarce in this region. This study examines the risk of hospital admission for hypertension in salinity-affected areas of the MDR. Methods: Cases and controls were obtained from national/provincial hospital admission records for 2013. The cases were adult patients whom hypertension (ICD10-code: I10-I15) was primary diagnosis for admission. Of the 13 provinces in the MDR, we identified seven as 'salinity exposed' and the remaining as 'non-exposed' areas. A multi-level logistic regression model was used to examine the association between salinity exposure and hypertension outcome. Results: Of the total 573 650 hospital admissions, 22 382 (~3.9%) were hypertensive cases. The multi-level logistic model combining both individual and ecological factors showed a 9% increase in risk (95% CI: 3-14%) of hypertension admission among individuals in exposed areas compared to those in non-exposed areas. Conclusion: In order to develop and promote appropriate adaptation strategies, further research is recommended to identify the salt exposure pathways and consumption behaviours in the salinity exposed areas.

Multi-micronutrient-fortified biscuits decreased the prevalence of anaemia and improved iron status, whereas weekly iron supplementation only improved iron status in Vietnamese school children.

In Vietnam, nutrition interventions do not target school children despite a high prevalence of micronutrient deficiencies. The present randomised, placebo-controlled study evaluated the impact of providing school children (n 403) with daily multiple micronutrient-fortified biscuits (FB) or a weekly Fe supplement (SUP) on anaemia and Fe deficiency. Micronutrient status was assessed by concentrations of Hb, and plasma ferritin (PF), transferrin receptor (TfR), Zn and retinol. After 6 months of intervention, children receiving FB or SUP had a significantly better Fe status when compared with the control children (C), indicated by higher PF (FB: geometric mean 36·9 (95% CI 28·0, 55·4) µg/l; SUP: geometric mean 46·0 (95% CI 33·0, 71·7) µg/l; C: geometric mean 34·4 (95% CI 15·2, 51·2) µg/l; P < 0·001) and lower TfR concentrations (FB: geometric mean 5·7 (95% CI 4·8, 6·52) mg/l; SUP: geometric mean 5·5 (95% CI 4·9, 6·2) mg/l; C: geometric mean 5·9 (95% CI 5·1, 7·1) mg/l; P = 0·007). Consequently, body Fe was higher in children receiving FB (mean 5·6 (sd 2·2) mg/kg body weight) and SUP (mean 6·1 (sd 2·5) mg/kg body weight) compared with the C group (mean 4·2 (sd 3·3) mg/kg body weight, P < 0·001). However, anaemia prevalence was significantly lower only in the FB group (1·0%) compared with the C group (10·4%, P = 0·006), with the SUP group being intermediate (7·4%). Children receiving FB had better weight-for-height Z-scores after the intervention than children receiving the SUP (P = 0·009). Vitamin A deficiency at baseline modified the intervention effect, with higher Hb concentrations in vitamin A-deficient children receiving FB but not in those receiving the SUP. This indicates that vitamin A deficiency is implicated in the high prevalence of anaemia in Vietnamese school children, and that interventions should take other deficiencies besides Fe into account to improve Hb concentrations. Provision of biscuits fortified with multiple micronutrients is effective in reducing anaemia prevalence in school children.