Multi-Objective Optimization for IRS-Aidded Multi-user MIMO SWIPT Systems

In this paper, we investigate an intelligent reflecting surface (IRS) assisted simultaneous wireless information and power transfer (SWIPT) system in which users equipped with multiple antennas exploit power-splitting (PS) strategies for simultaneously information decoding (ID) and energy harvesting (EH). Different from the majority of previous studies which focused on single objective optimization problems (SOOPs) and assumed the linearity of EH models, in this paper, we aim at studying the multi-objective optimization problem (MOOP) of the sum rate (SR) and the totalharvested energy (HE) subject to the maximum transmit power (TP) constraint, the user quality of service (QoS), and HE requirements at each user with taking a practical non-linear EH (NLEH) model into consideration. To investigate insightful tradeoffs between the achievable SR and total HE, we adopt the modified weighted Tchebycheff method to transform the MOOP into a SOOP. However, solving the SOOPs and modified SOOP is mathematically difficult due to the non-convexity of the object functions and the constraints of the coupled variables of the  base station (BS) transmit precoding matrices (TPMs), the user PS ratios (PSRs), and the IRS phase shift matrix (PSM). To address these challenges, an alternating optimization (AO) framework is used to decompose the formulated design problem into sub-problems. In addition, we apply the majorization-minimization (MM) approach to transform the sub-problems into convex optimization ones. Finally,  numerical simulation results are conducted to verify the tradeoffs between the SR and the total amount of HE. The numerical results also indicate that the considered system using the IRS with optimal phase shifts provides considerable performance improvement in terms of the achievable SR and HE as compared to the counterparts without using the IRS or with the IRS of fixed phase shifts

EVALUATION OF BIODEGRADATION RATE CONSTANT (K₁) AND BOD POLLUTION IN THE LAKE SYSTEM OF HANOI

Joint Research on Environmental Science and Technology for the Eart

Dry Eyes Status on Des Scale and Related Factors in Outpatients at Vietnam National Institute of Ophthalmology

BACKGROUND: Dry eye (DE) can effect on quality of life by pain, inability to perform certain activities that require prolonged attention (driving, reading,…) and productivity at work and finally effect to Q0L associated with DE. OSDI is scale questionnaire is created team to measure the quality of life related to ocular surface disease. AIM: To describe the dry eye disease according to OSDI scale and related factors of this disease. METHODS: A cross-sectional descriptive study was carried out on outpatients (≥ 16-year-old) who were examined and diagnosed with dry eyes at Vietnam National Institute Of Ophthalmology from April to July 2018. Data was collected using the OSDI questionnaire. RESULTS: The average age of participants was 44.6 years; 80.9% of patients were female; 39.9% were identified having mild dry eye. The related factors have been identified that associated with severe dry eye, including age OR = 1.03 (95%CI: 1.01-1.05, p = 0.005), binocular good vision OR = 0.11 (95%CI: 0.05-0.23; p < 0.0001), medical history OR = 17.09 (95%CI: 2.24-130.25; p < 0.0001), chronic conjunctivitis OR = 0.36 (95%CI: 0.14-0.91; p = 0.027), refractive errors OR = 0.14 (95%CI: 0.04-0.48; p < 0.0001), Sjogren's syndrome OR = 31.13 (95%CI: 7.08-136.76; p < 0.0001). CONCLUSION: Several related factors have been identified associated with severe dry eye, including: age, binocular good vision, medical history, chronic conjunctivitis, refractive errors, Sjogren's syndrome

Antibiotic Resistance Profile and Diversity of Subtypes Genes in Escherichia coli Causing Bloodstream Infection in Northern Vietnam

BACKGROUND: Evaluating the antibiotic susceptibility and resistance genes is essential in the clinical management of bloodstream infections (BSIs). But there are still limited studies in Northern Vietnam. AIM: The aim of the study was to determine the antibiotic resistance profile and characteristics of subtypes genes in Escherichia coli causing BSIs in Northern Vietnam. METHODS: The cross-sectional study was done in the period from December 2012 to June 2014 in two tertiary hospitals in Northern Vietnam. Tests were performed at the lab of the hospital. RESULTS: In 56 E. coli strains isolating 39.29 % produced ESBL. 100% of the isolates harbored blaTEM gene, but none of them had the blaPER gene. The prevalence of ESBL producers and ESBL non-producers in blaCTX-M gene was 81.82%, and 73.53%, in blaSHV gene was 18.18% and 35.29%. Sequencing results showed three blaTEM subtypes (blaTEM 1, 79, 82), four blaCTX-M subtypes (blaCTX-M-15, 73, 98, 161), and eight blaSHV subtypes (blaSHV 5, 7, 12, 15, 24, 33, 57, 77). Antibiotic resistance was higher in ampicillin (85.71%), trimethoprim/sulfamethoxazole (64.29%) and cephazolin (50%). Antibiotics were still highly susceptible including doripenem (96.43%), ertapenem (94.64%), amikacin (96.43%), and cefepime (89.29%). CONCLUSION: In Escherichia coli causing BSIs, antibiotic resistance was higher in ampicillin, trimethoprim/sulfamethoxazole and cephazolin. Antibiotics was highly susceptible including doripenem, ertapenem, amikacin, and cefepime

Antibiotic Resistance Profile and Methicillin-Resistant Encoding Genes of Staphylococcus aureus Strains Isolated from Bloodstream Infection Patients in Northern Vietnam

Background:  Evaluating the antibiotic susceptibility and resistance genes is essential in the clinical management of bloodstream infections (BSIs). Nevertheless, there are still limited studies in Northern Vietnam. AIM: This study aimed to determine the antibiotic resistance profile and methicillin-resistant encoding genes of Staphylococcus aureus (S. aureus) causing BSIs in Northern Vietnam. METHODS: The cross-sectional study was done from December 2012 to June 2014 in two tertiary hospitals in Northern Vietnam. Tests performed at the lab of the hospital. RESULTS:  In 43 S. aureus strains isolating, 53.5 % were MRSA. Distribution of gene for overall, MRSA, and MSSA strains were following: mecA gene (58.1 %; 95.7%, and 15%), femA gene (48.8%, 47.8%, and 50%), femB gene (88.4%, 82.6%, and 95%). Antibiotic resistance was highest in penicillin (100%), followed by erythromycin (65.1%) and clindamycin (60.5%). Several antibiotics were susceptible (100%), including vancomycin, tigecycline, linezolid, quinupristin/dalfopristin. Quinolone group was highly sensitive, include ciprofloxacin (83.7%), levofloxacin (86%) and moxifloxacin (86%). CONCLUSION:  In S. aureus causing BSIs, antibiotic resistance was higher in penicillin, erythromycin, and clindamycin. All strains were utterly susceptible to vancomycin, tigecycline, linezolid, quinupristin/dalfopristin

EFFECT OF CULTURE CONDITIONS FOR ANTIMICROBIAL ACTIVITY OF MARINE - DERIVED FUNGUS ASPERGILLUS FLOCCULOSUS 01NT.1.1.5

The biosynthesis of compounds with antibiotic activity produced by marine fungi, strongly depends on their growth conditions. A good understanding of the role of culture conditions in the biosynthesis of metabolites may lead to better exploitation of microbial metabolites. In this study, the influence of culture conditions including incubation period, initial pH and salinity on antimicrobial activity and secondary metabolites production of marine fungus 01NT.1.1.5 was investigated. This isolate, obtained from sponge Stylissa sp. in Nha Trang Bay, exhibited a broad spectrum of in vitro antimicrobial activity to Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 19111, Streptococcus faecalis ATCC 19433 and Candida albicans ATCC 10231. According to morphological characteristics and sequence analysis of 28S rDNA, the fungus was identified as Aspergillus flocculosus. The results indicated that antimicrobial activity and metabolite amount were highest when the fungus was cultivated in rice medium with incubation period of 20 days. The optimum salinity of 35 g/L and initial pH of 6.0 were found for the maximum antibiotic production. The colony growth, antimicrobial activity and production of secondary metabolites of the strain A. flocculosus 01NT.1.1.5 varied depending on salt concentrations and initial pH of medium. Particularly, extract of this fungus only showed activity against C. albicans when it was cultured in medium with 30-35 g/L salinity and initial pH 4.0-8.0. The results  indicate that salinity and initial pH along with cultivation period are important factors influencing antimicrobial activity and secondary metabolites of A. flocculosus 01NT.1.1.5, and might be for other marine fungi

Prospects for Food Fermentation in South-East Asia, Topics From the Tropical Fermentation and Biotechnology Network at the End of the AsiFood Erasmus+Project

Fermentation has been used for centuries to produce food in South-East Asia and some foods of this region are famous in the whole world. However, in the twenty first century, issues like food safety and quality must be addressed in a world changing from local business to globalization. In Western countries, the answer to these questions has been made through hygienisation, generalization of the use of starters, specialization of agriculture and use of long-distance transportation. This may have resulted in a loss in the taste and typicity of the products, in an extensive use of antibiotics and other chemicals and eventually, in a loss in the confidence of consumers to the products. The challenges awaiting fermentation in South-East Asia are thus to improve safety and quality in a sustainable system producing tasty and typical fermented products and valorising by-products. At the end of the “AsiFood Erasmus+ project” (www.asifood.org), the goal of this paper is to present and discuss these challenges as addressed by the Tropical Fermentation Network, a group of researchers from universities, research centers and companies in Asia and Europe. This paper presents current actions and prospects on hygienic, environmental, sensorial and nutritional qualities of traditional fermented food including screening of functional bacteria and starters, food safety strategies, research for new antimicrobial compounds, development of more sustainable fermentations and valorisation of by-products. A specificity of this network is also the multidisciplinary approach dealing with microbiology, food, chemical, sensorial, and genetic analyses, biotechnology, food supply chain, consumers and ethnology

Design of Zeolite-Covalent Organic Frameworks for Methane Storage

A new type of zeolite-based covalent organic frameworks (ZCOFs) was designed under different topologies and linkers. In this study, the silicon atoms in zeolite structures were replaced by carbon atoms in thiophene, furan, and pyrrole linkers. Through the adoption of this strategy, 300 ZCOFs structures were constructed and simulated. Overall, the specific surface area of ZCOFs is in the range of 300–3500 m2/g, whereas the pore size is distributed from 3 to 27 Å. Furthermore, the pore volume exhibits a wide range between 0.01 and 1.5 cm3/g. Screening 300 ZCOFs with the criteria towards methane storage, 11 preliminary structures were selected. In addition, the Grand Canonical Monte Carlo technique was utilized to evaluate the CH4 adsorption ability of ZCOFs in a pressure ranging from 1 to 85 bar at a temperature of 298 K. The result reveals that two ZCOF structures: JST-S 183 v/v (65–5.8 bar) and NPT-S 177 v/v (35–1 bar) are considered as potential adsorbents for methane storage. Furthermore, the thermodynamic stability of representative structures is also checked base on quantum mechanical calculations

Sequencing and analysis of the mitochondrial genome of Pennahia anea (Bloch, 1793) (Perciformes: Sciaenidae)

Donkey croaker, Pennahia anea (Bloch, 1793) is a commercially important croaker in the Indo-Pacific region. In this study, we sequenced and analyzed the mitogenome of P. anea. The nearly complete mitochondrial genome of P. anea is 15,694 bp in size. It contained 13 protein-coding genes (PCGs), 2 rRNA genes, and 22 tRNA genes. The sequence had the A-T content of 55.4% and GC content of 44.6%. All 13 PCGs used ATG codon for initiation, while TAA codon was the most common for termination. Phylogenetic analysis demonstrated that P. anea is located within the genus Pennahia. This study provides additional data for the understanding of the phylogeny of the family Sciaenidae

Prevalence and Risk Factors of Hypertension in Two Communes in the Vietnam Northern Mountainous, 2017

Background. The aims were to characterize the prevalence of hypertension (HTN) and explore its associations in the northern mountainous. Methods. We carried out a cross-sectional study in two communes in Chiem Hoa district, Tuyen Quang province, between June and November 2017. All subjects at the age of 18 years and over currently living in two communes. The usage of the descriptive statistics was to characterize the HTN prevalence. We used the univariate and multivariate models of logistic regression to determine the prevalence and related factors of HTN. Results. There were 319 people with overall HTN in the total of 675 participants. Among people with HTN, there were 101 ones with isolated systolic hypertension (ISH). The proportion of HTN among the Tay ethnic group was 47.6%. The factors related to HTN included group, body mass index (BMI), low physical fitness, and waist-hip ratio (WHR). These factors as well as the ethnicity were significantly associated with ISH. Conclusions. Two communes of Chiem Hoa district in Tuyen Quang province had a high prevalence of HTN. Age, BMI, WHR, and physical activity were the risk factors of overall HTN and ISH. In particular, ISH was affected by ethnicity