Solution of Linear Programming Problems using a Neural Network with Non-Linear Feedback

This paper presents a recurrent neural circuit for solving linear programming problems. The objective is to minimize a linear cost function subject to linear constraints. The proposed circuit employs non-linear feedback, in the form of unipolar comparators, to introduce transcendental terms in the energy function ensuring fast convergence to the solution. The proof of validity of the energy function is also provided. The hardware complexity of the proposed circuit compares favorably with other proposed circuits for the same task. PSPICE simulation results are presented for a chosen optimization problem and are found to agree with the algebraic solution. Hardware test results for a 2–variable problem further serve to strengthen the proposed theory

FORMULATION AND EVALUATION OF PECTIN-CALCIUM CHLORIDE BEADS OF AZATHIOPRINE FOR COLON TARGETED DRUG DELIVERY SYSTEM

Objective: Calcium pectinate is an insoluble hydrophilic material used for sustained release delivery. The objective of the study was formulation and evaluation pectin-calcium chloride beads of azathioprine.Methods: Calibration curves of azathioprine were prepared in 0.1N HCl solution (pH-1.2) and phosphate buffer (pH-6.8 and pH-7.4). Fourier transform infrared spectroscopy and differential scanning calorimetry was used to determine compatibility between azathioprine and excipients. Formulation and optimization of calcium-pectinate beads were performed. The coating of the optimized batch was performed with eudragit S100. Micrometric properties, scanning electron microscopy, in vitro azathioprine release, and stability study was performed. Dissolution kinetic study was assessed for various kinetics models of the optimized batch. The Wilcoxon test followed by the Dunnett's multiple comparison tests were performed between uncoated and coated beads in vitro dissolution profile of optimized batch in 0.1N HCl after 2 h.Results: Fourier transform infrared spectroscopy and differential scanning calorimetry had identical peaks with that of pure azathioprine in compatibility study. Scanning electron microscopy of an uncoated optimized batch of beads indicated the smooth and uniform surface of prepared beads. Eudragit S100 coating was decreased release of azathioprine release in 0.1N HCl after 2 h (p = 0.049, q = 3.533). Korsmeyer/Peppa's model was applied with release exponent higher than 1. In vitro percentage cumulative azathioprine release was identical before and after stability study.Conclusion: Calcium pectinate beads of azathioprine, a multi-particulate dosage form using pH-dependent approaches were prepared

PREPARATION OF BUDESONIDE-PECTIN BEADS USING THE PERISTALTIC PUMP

Objective: To formulate and evaluate budesonide-pectin beads using novel assembly with a peristaltic pump.Methods: The prepared budesonide-pectin dispersion was added to calcium chloride solution with the help of assembly. Provided at least 2 h for hardening and dried at 60 °C for 3 h. Assembly was assembled with the use of a peristaltic pump, polymeric solution reservoir, hose, needle, magnetic stirrer, gelling bath. One side of hose was dipped in pectin solution container and another side was passed through the peristaltic pump and connected to the needle. Peristaltic pump produced pumping of pectin solution through the hose. Needles with variable diameters are available. The gelling bath was kept on magnetic stirrer to keep prepared beads in motion, which helped to provide new surface and sufficient reaction time and helped to avoid agglomeration. There were 10 different batches with different process parameters prepared. Production yield, the diameter of beads, swelling index, and in vitro budesonide dissolution in phosphate buffer pH 7.4 after 5 h was determined.Results: There was a significant difference between selection of process parameter among the batches (p = 0.049, q = 6.11). As nozzle diameter was increased, percentage yield was decreased (p = 0.0038, q>5.98). However, if hardening time was decreased percentage release was increased (p = 0.0361, q>5.98).Conclusion: The novel assembly for bead generation had developed a uniform, spherical shaped, and smooth surfaced beads

Factors Affecting Grid-independent Results for Compartment Fire Modelling

Obtaining grid independent results for compartment fires using a computational fluid dynamics (CFD) model is a major challenge, especially when the fire is not prescribed. While simulating a fire scenario using a CFD model, most fire safety engineers use computational cell sizes that can only be supported by their computing resources which may lead to a large error. This paper presents a systematic study to obtain a grid independent result from CFD simulations of an ISO 9705 room fire experiment using the CFD package Fire Dynamics Simulator (FDS) which incorporates a large eddy simulation (LES) methodology along with a mixture fraction combustion model. The experiment involved ignition of two trays of liquid fuel placed in the room and the growth and development of this fire. The study shows that initially as the grid sizes decrease the size of the fire increases and then the fire size starts decreasing to an asymptotic value as the grid sizes decreases further. A discussion is presented on the factors in relation to “goodness” of the grid resolution such as the changing trend of characteristic fire diameters, the size of computational cells etc

Association of sickle cell disease with anthropometric indices among under-five children: evidence from 2018 Nigeria Demographic and Health Survey

BACKGROUND: Malnutrition continues to affect under-five children in Africa to an overwhelming proportion. The situation is further compounded by the burden of sickle cell disease (SCD). However, association of SCD with stunting, wasting, and underweight in a nationally representative sample of under-five children remains unexplored. We aimed to describe prevalence of undernutrition by sickle cell status, to evaluate its association with growth faltering ascertained by anthropometric indices, and to explore mediating role of hemoglobin. METHODS: We availed data from the 2018 Nigeria Demographic and Health Survey (DHS) and the sample comprised 11,233 children aged 6-59 months who were successfully genotyped for SCD. The DHS employed a two-stage, stratified sampling strategy. SickleSCAN rapid diagnostic test was used for SCD genotyping. Z-scores of length/height-for-age (HAZ), weight-for-height (WHZ), and weight-for-age (WAZ) were computed against the 2006 World Health Organization Child Growth Standards. We fitted logistic regression models to evaluate association of SCD with stunting, wasting, and underweight. Mediation analysis was performed to capture the indirect effect of and proportion of total effect mediated through hemoglobin level in SCD-anthropometric indices association. RESULTS: Prevalences of stunting, wasting, and underweight among children with SCD were 55.4% (54.5-56.4), 9.1% (8.6-9.7), and 38.9% (38.0-39.8), respectively. The odds of stunting were 2.39 times higher (adjusted odds ratio (aOR) 2.39, 95% CI: 1.26-4.54) among sickle children than those with normal hemoglobin. SCD was also significantly associated with underweight (aOR 2.64, 95% CI: 1.25-5.98), but not with wasting (aOR: 1.60, 95% CI 0.85-3.02). Association of SCD with all three anthropometric indices was significantly mediated through hemoglobin level: for SCD-HAZ, the adjusted indirect effect (aIE) was - 0.328 (95% CI: - 0.387, - 0.270); for SCD-WHZ, the aIE was - 0.080 (95% CI: - 0.114, - 0.050); and for SCD-WAZ, the aIE was - 0.245 (95% CI: - 0.291, - 0.200). CONCLUSION: We presented compelling evidence of the negative impact of SCD on anthropometric indices of nutritional status of under-five children. Integration of a nutrition-oriented approach into a definitive SCD care package and its nationwide implementation could bring promising results by mitigating the nutritional vulnerability of children with SCD

Tracking analysis of normalized adaptive algorithms

Tracking analysis of normalized adaptive algorithms is carried out in the presence of two sources of nonstationarities: carrier frequency offset between transmitter and receiver; random variations in the environment. A unified approach is carried out using a mixed-norm-type error nonlinearity. Close agreement between analytical analysis and simulation results is obtained for the case of the NLMS algorithm. The results show that, unlike the stationary case, the steady-state excess-mean-square error is not a monotonically increasing function of the step-size, while the ability of the adaptive algorithm to track the variations in the environment degrades by increasing the frequency offset

Tracking analysis of the NLMS algorithm in the presence of both random and cyclic nonstationarities

Tracking analysis of the normalized least mean square (NLMS) algorithm is carried out in the presence of two sources of nonstationarities: 1) carrier frequency offset between transmitter and receiver; 2) random variations in the environment. A novel approach to this analysis is carried out using the concept of energy conservation. Close agreement between analytical analysis and simulation results is obtained. The results show that, unlike in the stationary case, the steady-state excess MSE is not a monotonically increasing function of the step size. Moreover, the ability of the adaptive algorithm to track the variations in the environment is shown to degrade with increasing frequency offset

Tracking analysis of the NLMS algorithm in the presence of both random and cyclic nonstationarities

Tracking analysis of the normalized least mean square (NLMS) algorithm is carried out in the presence of two sources of nonstationarities: 1) carrier frequency offset between transmitter and receiver; 2) random variations in the environment. A novel approach to this analysis is carried out using the concept of energy conservation. Close agreement between analytical analysis and simulation results is obtained. The results show that, unlike in the stationary case, the steady-state excess MSE is not a monotonically increasing function of the step size. Moreover, the ability of the adaptive algorithm to track the variations in the environment is shown to degrade with increasing frequency offset

Effects of Aluminium Exposures on Growth, Photosynthetic Efficiency, Lipid Peroxidation, Antioxidant Enzymes and Artemisinin Content of Artemisia annua L.

Acid soils are widely distributed at a global scale; under acidic conditions, the solubility of aluminium (Al) increases and the elevated concentration of toxic Al3+ in soil solution seriously limits crop production. There is no information on the effects of aluminium (Al) on Artemisia annua L., which is a most important antimalarial plant in the recent time being artemisinin; responsible for its antimalarial activity. In this report, we describe the effects of Al contamination on growth, photosynthetic efficiency, membrane damage, antioxidant enzyme activities and changes in artemisinin content in A. annua. Al addition to the soil medium significantly reduced the yield and growth of the plants. Lower values of net photosynthetic rate, stomatal conductance, internal CO2 and total chlorophyll content were observed as a result of different Al concentrations applied. The activities of nitrate reductase (NR) and carbonic anhydrase (CA) were also found to be hampered by Al exposure to the plants. Al enhanced lipid peroxidation rate (TBRAS content) and activated the activities of catalase (CAT), peroxidase (POX) and superoxide dismutase (SOD) enzymes in the treated plants. The elicitation in the endogenous ROS levels, due to the Al treatments, was also noticed in the present study. Furthermore, enhanced artemisinin content and yield was obtained at 0.10mM concentration of soil applied Al. Our study provides evidence that excess Al in soil hamper the growth and yield, slow down the activities of NR and CA, induce lipid peroxidation and antioxidant enzymes but a low level of Al-toxicity can induce artemisinin content in A. annua plants.Key words: Aluminium (Al); Artemisia annua L.; Artemisinin; Lipid peroxidation; Reactive oxygen species (ROS)Tariq Aftab et al. Effects of Aluminium Exposures on Growth, Photosynthetic Efficiency, Lipid Peroxidation, Antioxidant Enzymes and Artemisinin Content of Artemisia annua L. J Phytol 2/8(2010) 23-37