Enhanced Quadratic V/f-Based Induction Motor Control of Solar Water Pumping System

In rural and remote areas, solar photovoltaic energy (PV) water pumping systems (SPWPSs) are being favored over diesel-powered water pumping due to environmental and economic considerations. PV is a clean source of electric energy offering low operational and maintenance cost. However, the direct-coupled SPWPS requires inventive solutions to improve the system’s efficiency under solar power variations while producing the required amount of pumped water concurrently. This paper introduces a new quadratic V/f (Q V/f) control method to drive an induction motor powered directly from a solar PV source using a two-stage power converter without storage batteries. Conventional controllers usually employ linear V/f control, where the reference motor speed is derived from the PV input power and the dc-link voltage error using a simple proportional–integral (PI) controller. The proposed Q V/f-based system is compared with the conventional linear V/f control using a simulation case study under different operating conditions. The proposed controller expectedly enhances the system output power and efficiency, particularly under low levels of solar irradiance. Some alternative controllers rather than the simple PI controller are also investigated in an attempt to improve the system dynamics as well as the water flow output. An experimental prototype system is used to validate the proposed Q V/f under diverse operating conditions

IFN-α-based treatment of patients with chronic HCV show increased levels of cells with myeloid-derived suppressor cell phenotype and of IDO and NOS

<p><b>Introduction:</b> Hepatitis C virus (HCV) infection causes chronic hepatitis, which is often associated with suppressed anti-HCV immune responses. We have recently reported accumulation of myeloid-derived suppressor cells (MDSCs) and suppressed immunity in cancer patients.</p> <p><b>Aim:</b> The main aim of this study was to determine whether chronic HCV patients harbor high of MDSCs in general and in nonresponders to IFN-based therapy in particular as well as to analyze the immune suppressive molecules.</p> <p><b>Methods:</b> Peripheral blood samples withdrawn from 154 patients with chronic HCV infection and were categorized into responders and nonresponders based on viral titer upon IFN-α treatment.</p> <p><b>Results:</b> The relative and absolute numbers of MDSCs defined as Lin⁻/HLA-DR⁻/CD33⁺/CD11b⁺ increased in all HCV patients, where they were higher in nonresponders than in responders. Additionally, the levels of MDSCs after 4–6 months of treatment in responders were lower than during the course of treatment. The responders also showed higher levels of IL-2 coincided with increased numbers of dendritic cells (DCs), CD4⁺ and CD8⁺ T cells. The levels of total NOS and IDO were also higher in nonresponders as compared to responders and healthy controls, while the expression levels of CD3ζ was lower in responders as compared to nonresponders and healthy volunteers.</p> <p><b>Conclusion:</b> Chronic HCV patients harbor high numbers of MDSCs, which are higher in nonresponders than in responders. The higher numbers of MDSCs associated with increases in the suppressing factors.</p

The impact of excluding adverse neonatal outcomes on the creation of gestational weight gain charts among women from low- and middle-income countries with normal and overweight BMI

Background Existing gestational weight gain (GWG) charts vary considerably in their choice of exclusion/inclusion criteria, and it is unclear to what extent these criteria create differences in the charts’ percentile values. Objectives We aimed to establish the impact of including/excluding pregnancies with adverse neonatal outcomes when constructing GWG charts. Methods This is an individual participant data analysis from 31 studies from low- and middle-income countries. We created a dataset that included all participants and a dataset restricted to those with no adverse neonatal outcomes: preterm 4000 g. Quantile regression models were used to create GWG curves from 9 to 40 wk, stratified by prepregnancy BMI, in each dataset. Results The dataset without the exclusion criteria applied included 14,685 individuals with normal weight and 4831 with overweight. After removing adverse neonatal outcomes, 10,479 individuals with normal weight and 3466 individuals with overweight remained. GWG distributions at 13, 27, and 40 wk were virtually identical between the datasets with and without the exclusion criteria, except at 40 wk for normal weight and 27 wk for overweight. For the 10th and 90th percentiles, the differences between the estimated GWG were larger for overweight (∼1.5 kg) compared with normal weight (<1 kg). Removal of adverse neonatal outcomes had minimal impact on GWG trajectories of normal weight. For overweight, the percentiles estimated in the dataset without the criteria were slightly higher than those in the dataset with the criteria applied. Nevertheless, differences were <1 kg and virtually nonexistent at the end of pregnancy. Conclusions Removing pregnancies with adverse neonatal outcomes has little or no influence on the GWG trajectories of individuals with normal and overweight