Physiological and biochemical changes in longan fruit (Dimocarpus longan Lour.) cultivated in Vietnam during growth and ripening

333-339This paper presents research results on some physiological (pigments content) and biochemical indicators (reducing sugar content, starch, total organic acid, vitamin C, α-amylase enzyme, catalase enzyme, peroxidase enzyme) of longan fruit grown in Vietnam during growth and ripening, thereby determining the physiological ripening time of the fruit (the most appropriate time for fruit harvest). The results showed that significant changes occurred in pigments content, reducing sugar content, starch, total organic acid, vitamin C, protein, lipid, α-amylase enzyme, catalase enzyme, and peroxidase enzyme of longan from formation to fruit ripening. Through the research process, it was observed that the longan achieved the best quality to harvest when fruits were 19 weeks old. The results of this study provide important data for the harvesting and storage of longan fruit

Physiological and biochemical changes in longan fruit (Dimocarpus longan Lour.) cultivated in Vietnam during growth and ripening

This paper presents research results on some physiological (pigments content) and biochemical indicators (reducing sugar content, starch, total organic acid, vitamin C, α-amylase enzyme, catalase enzyme, peroxidase enzyme) of longan fruit grown in Vietnam during growth and ripening, thereby determining the physiological ripening time of the fruit (the most appropriate time for fruit harvest). The results showed that significant changes occurred in pigments content, reducing sugar content, starch, total organic acid, vitamin C, protein, lipid, α-amylase enzyme, catalase enzyme, and peroxidase enzyme of longan from formation to fruit ripening. Through the research process, it was observed that the longan achieved the best quality to harvest when fruits were 19 weeks old. The results of this study provide important data for the harvesting and storage of longan fruit

HỢP CHẤT STEROID VÀ FLAVONE TỪ THÂN RỄ THIÊN NIÊN KIỆN LÁ LỚN (Homalomena pendula)

Phytochemical investigation of the rhizomes of Homalomena pendula resulted in the isolation of one flavone and three steroids. These compounds were determined as tangeretin (1), ergosterol peroxide (2), sitoindoside I (3), and stigmasterol (4) on the basis of 1D and 2D NMR data and in comparison with the available data in the literature. Compounds 1‒3 were found for the first time from the genus Homamomena. The n-hexane and ethyl acetate extracts show NO production inhibitory activity in RAW 264.7 macrophage cells with IC50 values of 46.8 and 75.52 µg·mL–1.Hợp chất flavone, tangeretin (1), và ba hợp chất steroid: ergosterol peroxide (2), sitoindoside I (3) và stigmasterol (4) đã được phân lập từ thân rễ của cây thiên niên kiện lá lớn (Homalomena pendula). Cấu trúc hóa học của chúng được xác định dựa trên phân tích dữ liệu phổ cộng hưởng từ hạt nhân (1D và 2D NMR) và so sánh với các tài liệu đã công bố. Các hợp chất (1-3) được phân lập lần đầu tiên từ chi Homalomena. Cao chiết n-hexane và ethyl acetate của cây này có hoạt tính ức chế sản sinh NO trên đại thực bào RAW 264.7 kích thích bằng lipopolysaccharide với các giá trị IC50 là 46,80 và 75,52 µg·mL–1

The induction and identification of novel Colistin resistance mutations in Acinetobacter baumannii and their implications.

Acinetobacter baumannii is a significant cause of opportunistic hospital acquired infection and has been identified as an important emerging infection due to its high levels of antimicrobial resistance. Multidrug resistant A. baumannii has risen rapidly in Vietnam, where colistin is becoming the drug of last resort for many infections. In this study we generated spontaneous colistin resistant progeny (up to >256 μg/μl) from four colistin susceptible Vietnamese isolates and one susceptible reference strain (MIC <1.5 μg/μl). Whole genome sequencing was used to identify single nucleotide mutations that could be attributed to the reduced colistin susceptibility. We identified six lpxACD and three pmrB mutations, the majority of which were novel. In addition, we identified further mutations in six A. baumannii genes (vacJ, pldA, ttg2C, pheS and conserved hypothetical protein) that we hypothesise have a role in reduced colistin susceptibility. This study has identified additional mutations that may be associated with colistin resistance through novel resistance mechanisms. Our work further demonstrates how rapidly A. baumannii can generate resistance to a last resort antimicrobial and highlights the need for improved surveillance to identified A. baumannii with an extensive drug resistance profile

Clinical and Microbiological Features of Pediatric Endopthalmitis After Open Globe Injury in the North of VietNam

BACKGROUND: Pediatric endophthalmitis after open-globe injury had its clinical features, microbiological profile different from those in aldults. In Viet Nam, there was no report on the clinical and microbiological characteristic of pediatric posttraumatic endophthalmitis. Therefore, we conduct this study. AIM: To describe clinical features, ultrasound results, gram stain and culture results of endophthalmitis in pediatric open globe injuries. METHODS: Prospective non-controlled study. Case series of 30 eyes presenting with post-traumatic endophthalmitis between 2015 and 2016 were reviewed. RESULTS: Mean age was 8.03 ± 3.99 years. Metallic and organic etiologies were most common causes for injuries (n = 11). 27 cases had penetrating corneal trauma. Dense opaque vitreous was seen in 25 eyes. Retinal necrosis &lt; 1 quadrant and chorioretinal abscess &gt; 1 quadrant were most common fundus lesions. Dense vitreous opacity on ultrasound was most common (n = 28). Gram stain bacteria positivity was 93.3%, gram-positive were isolated in 63.3%. Vitreous samples were more often positive than aqueous (P = 0,002). CONCLUSION: Posttraumatic endophthalmitis in children is more common in boys aged 6-10 years and most often caused by injury with metallic and organic matter. Culture results were very low. Vitreous samples were more often positive than aqueous. Gram-positive bacteria were the most common causative organism

Adsorption of Methyl Orange Dyes on Oriented Co/Fe-MOF Bimetallic Organic Framework in Wastewater Treatment

The production of highly efficient and reusable adsorbents that can be used in pigment treatment has been of great scientific interest. Metallic organic frameworks (MOFs) are considered a new type of material with extremely diverse structures and can be used as adsorbents to remove environmental pollutants. The selected Co/Fe-MOF material was synthesized in this study by using the solvent-thermal method. Then, the effects of several influencing factors such as adsorbent dosage, pH, initial concentration of MO, and exposure time on the adsorption capacity of methyl orange (MO) dyes by Co/Fe-MOF were evaluated. Under acidic conditions (pH 4), the effective removal of MO from aqueous solution reached equilibrium after 60 min upon exposure to MO at the concentration of 200 mg/L, and the adsorption capacity was 137.6 mg/g. The two models of adsorption isotherms, Freundlich and Langmuir, showed good compatibility with the experimental data, and the calculated correlation coefficients (R2) were both greater than 0.96. The MO adsorption efficiency was proposed to fit the pseudo-quadratic and pseudo-first-order kinetic models. Therefore, MOF materials can be considered as a potential agent for wastewater treatment, thereby providing a possible solution to solve water pollution

Blood pressure percentiles and systemic hypertension-associated factors among children aged between 6 and 15 years in Southern Vietnam

Background: The present study determined blood pressure percentiles in children aged between 6 and 15 years in Southern Vietnam. Material and methods: Blood pressure was measured in a random sample of 1080 students aged 6–15 years who was studying at primary and secondary high schools in My Tho city, Vietnam. A descriptive cross-sectional study was conducted from November 2019 to June 2020. To diagnose children systemic hypertension, the blood pressure must be above the 95th percentile. Data were analyzed by IBM SPSS statistics software version 20.0. The Chi-squared test was employed to evaluate the relationship between systemic hypertension and child demographic characteristics including gender and obesity. Results: The results showed that the 95th percentiles of systolic and diastolic blood pressure of the children was 110/70 mm Hg in the 6-year-old group, 120/75 mm Hg in the 7 to12-year-old group and 125/80 mm Hg in the 13 to 15-year-old group, respectively. The rate of systemic hypertension in the children was 10% whereas boys had a 1.2 time higher risk of systemic hypertension than girls (p &gt; 0.05). Obese children had an 8.6 time higher risk of systemic hypertension than non-obese ones (p &lt; 0.001). Conclusion: The blood pressure percentile chart of school children aged 6–15 years were reported here for the first time in Vietnam. The results provided useful information in early diagnosis and timely treatment of systemic hypertension in children

The Epidemiology of Interpandemic and Pandemic Influenza in Vietnam, 2007–2010: The Ha Nam Household Cohort Study I

Prospective community-based studies have provided fundamental insights into the epidemiology of influenza in temperate regions, but few comparable studies have been undertaken in the tropics. The authors conducted prospective influenza surveillance and intermittent seroprevalence surveys in a household-based cohort in Vietnam between December 2007 and April 2010, resulting in 1,793 person-seasons of influenza surveillance. Age- and sex-standardized estimates of the risk of acquiring any influenza infection per season in persons 5 years of age or older were 21.1% (95% confidence interval: 17.4, 24.7) in season 1, 26.4% (95% confidence interval: 22.6, 30.2) in season 2, and 17.0% (95% confidence interval: 13.6, 20.4) in season 3. Some individuals experienced multiple episodes of infection with different influenza types/subtypes in the same season (n = 27) or reinfection with the same subtype in different seasons (n = 22). The highest risk of influenza infection was in persons 5–9 years old, in whom the risk of influenza infection per season was 41.8%. Although the highest infection risk was in school-aged children, there were important heterogeneities in the age of infection by subtype and season. These heterogeneities could influence the impact of school closure and childhood vaccination on influenza transmission in tropical areas, such as Vietnam

CHẾ TẠO VÀ TÍNH CHẤT CỦA VẬT LIỆU TỔ HỢP GRAPHENE – ỐNG NANO CÁCBON – HẠT NANO VÀNG

In this work, a composite nanomaterial consisting of graphene (Gr), double-wall carbon nanotube (DWCNTs) and gold nanoparticles (AuNPs), designated as DWCNTs-AuNPs-Gr was synthesized via the thermal chemical vapour deposition technique. The morphology and electrical and electrochemical properties of the material were characteried by using field emission scanning electron microscopy, Raman spectroscopy, four-probe sheet resistance measurement, and cyclic voltammetry (CV). The average sheet resistance value of DWCNTs-AuNPs-Gr is 549 W/sq, 2.3 times lower than that of graphene. The current response of a DWCNTs-AuNPs-Gr-modified electrode in a 2 mM K3[Fe(CN)6]/K4[Fe(CN)6] solution with 0.1 M PBS is 15.79 µA, 1.48 times higher than that of a graphene-modified electrode and 2.57 times higher than that of a bare electrode. The DWCNTs-AuNPs-Gr material can be used for electrochemical biosensors to detect various bioelements.Trong công trình này, màng tổ hợp của vật liệu graphene (Gr) – ống nano cácbon hai tường (DWCNT) và hạt nano kim loại vàng (AuNPs) (DWCNT-AuNPs-Gr) đã được chế tạo bằng phương pháp lắng đọng pha hơi nhiệt hóa học (CVD). Hình thái học bề mặt và các tính chất điện, điện hóa của vật liệu tổ hợp đã được khảo sát thông qua kính hiển vi điện tử quét phát xạ trường, phổ Raman, điện trở bốn mũi dò và kỹ thuật quét thế vòng (CV). Với nồng độ DWCNTs 0,3 g/L và tốc độ quay phủ 4000 vòng/phút, vật liệu DWCNTs-AuNPs-Gr có điện trở bề mặt giảm 2,3 lần so với màng Gr và đạt khoảng 549 W/sq; dòng đỉnh đáp ứng trong dung dịch 2 mM K3[Fe(CN)6]/K4[Fe(CN)6] trong 0,1 M PBS đạt 15,79 µA tại 50 mV/s, cao gấp 1,48 lần so với điện cực biến tính màng Gr và gấp 2,57 lần so với điện cực trần. Vật liệu DWCNTs-AuNPs-Gr có tiềm năng ứng dụng trong cảm biến điện hóa để phát hiện các phần tử sinh học khác nhau