VRF IN HEATING MODE

Variable refrigerant flow (VRF) air conditioning system has become attractive due to better energy performances than traditional air conditioning systems. However, the shortcoming of no outdoor air (OA) intake has not been solved thoroughly. A new VRF and outdoor air processing unit combined air conditioning system is proposed and simulated. The first obstacle is that there is no well-known simulation tool for VRF unit in heating mode. A VRF model of condenser-number independence is developed and validated first. The combined system is modeled by integrating the individual sub-system or component models into a complete system. The average error of the developed model to predict heating capacity, input power and COP are 7.87%, 12.45% and 6.19% respectively

Antibiotic residues in milk and eggs of commercial and local farms at Chittagong, Bangladesh

Aim: The study was conducted to detection and determination of concentration or level of antibiotic residues in milk and egg of local and commercial farms at Chittagong during December 2011 to June 2012. Materials and Methods: A total of 400 (200 milk and 200 egg) samples were collected from local and commercial dairy cows and local scavenging and commercial poultry farms, respectively. Microbial inhibition test and thin layer chromatography were used for screening and ultra-high performance liquid chromatography was used to estimate the concentrations of antibiotic residues in samples. Results: Tetracycline, amoxicillin, and ciprofloxacin residues were significantly (p ≤ 0.05) higher in commercial farms than local. The boiling insignificantly (p˃0.05) reduced residues level in milk and egg. The average concentrations of amoxicillin residue in local milk, commercial milk, local egg, and commercial egg were 9.84 μg/ml, 56.16 μg/ml, 10.46 μg/g and 48.82 μg/g, respectively, in raw samples and were reduced to 9.81 μg/ml, 55.54 μg/ml, 10.29 μg/g, and 48.38 μg/g, respectively, after boiling. Conclusions: Proper maintaining of the withdrawal period and development of active surveillance system are highly recommended for public health security

Silicene Quantum Capacitance Dependent Frequency Readout to a Label-Free Detection of DNA Hybridization— A Simulation Analysis

The use of deoxyribonucleic acid (DNA) hybridization to detect disease-related gene expression is a valuable diagnostic tool. An ion-sensitive field-effect transistor (ISFET) with a graphene layer has been utilized for detecting DNA hybridization. Silicene is a two-dimensional silicon allotrope with structural properties similar to graphene. Thus, it has recently experienced intensive scientific research interest due to its unique electrical, mechanical, and sensing characteristics. In this paper, we proposed an ISFET structure with silicene and electrolyte layers for the label-free detection of DNA hybridization. When DNA hybridization occurs, it changes the ion concentration in the surface layer of the silicene and the pH level of the electrolyte solution. The process also changes the quantum capacitance of the silicene layer and the electrical properties of the ISFET device. The quantum capacitance and the corresponding resonant frequency readout of the silicene and graphene are compared. The performance evaluation found that the changes in quantum capacitance, resonant frequency, and tuning ratio indicate that the sensitivity of silicene is much more effective than graphene

Nutritional status and dietary diversity of pregnant and nonpregnant reproductive‐age Rohingya women

Abstract There are no data on the nutritional status and dietary diversity of the pregnant and nonpregnant reproductive‐age Rohingya women who have recently shifted to the Bhasan Char Relocation Camp located on an island in the Bay of Bengal. A cross‐sectional survey was conducted in November–December, 2021 to assess the nutritional status and evaluate the dietary diversity of two vulnerable groups of the forcibly displaced Rohingya population: nonpregnant reproductive‐age women and pregnant mothers. Multivariable logistic regression was applied to identify the factors associated with nutritional impairments. Overall, 7.6% of the nonpregnant reproductive‐age women were underweight (Body Mass Index [BMI] < 18.5 kg/m2), and nearly one‐third of them had a BMI ≥ 25 kg/m2. However, 26.7% of the pregnant mothers were undernourished (BMI < 20.0 kg/m2) and almost one‐fourth of them were either overweight or obese (BMI ≥ 25.0 kg/m2). The prevalence of thinness (Mid Upper Arm Circumference [MUAC] < 23 cm) was 34.5% among pregnant mothers, and 10.1% of them were severely thin (MUAC < 21 cm). The mean (±SD) of the Women's Dietary Diversity Score (WDDS) was 3.3 (±1.1) for nonpregnant reproductive‐age women and 3.7 (±1.3) for pregnant mothers enrolled in this study. Overall, 63.8% of the nonpregnant women of childbearing age and 46% of the pregnant mothers had a low WDDS (WDDS < 4). The WDDS was found to be protective against thinness among nonpregnant reproductive‐age women (AOR = 0.61; 95% CI = 0.37, 0.93; p‐value = .03) and low BMI in pregnant mothers (AOR = 0.71; 95% CI = 0.55, 0.91; p‐value = .01). The results of this survey will assist in early recognition of the nutritional demands, and act as a guide to planning nutrition‐based programs among Rohingya reproductive‐age women relocated to the Bhasan Char Island