Comparative Study of Sensorless Control Methods of PMSM Drives

Recently, permanent magnet synchronous motors (PMSMs) are increasingly used in high performance variable speed drives of many industrial applications. This is because the PMSM has many features, like high efficiency, compactness, high torque to inertia ratio, rapid dynamic response, simple modeling and control, and maintenance-free operation. In most applications, the presence of such a position sensor presents several disadvantages, such as reduced reliability, susceptibility to noise, additional cost and weight and increased complexity of the drive system. For these reasons, the development of alternative indirect methods for speed and position control becomes an important research topic. Many advantages of sensorless control such as reduced hardware complexity, low cost, reduced size, cable elimination, increased noise immunity, increased reliability and decreased maintenance. The key problem in sensorless vector control of ac drives is the accurate dynamic estimation of the stator flux vector over a wide speed range using only terminal variables (currents and voltages). The difficulty comprises state estimation at very low speeds where the fundamental excitation is low and the observer performance tends to be poor. The reasons are the observer sensitivity to model parameter variations, unmodeled nonlinearities and disturbances, limited accuracy of acquisition signals, drifts, and dc offsets. Poor speed estimation at low speed is attributed to data acquisition errors, voltage distortion due the PWM inverter and stator resistance drop which degrading the performance of sensorless drive. Moreover, the noises of system and measurements are considered other main problems. This paper presents a comprehensive study of the different methods of speed and position estimations for sensorless PMSM drives. A deep insight of the advantages and disadvantages of each method is investigated. Furthermore, the difficulties faced sensorless PMSM drives at low speeds as well as the reasons are highly demonstrated. Keywords: permanent magnet, synchronous motor, sensorless control, speed estimation, position estimation, parameter adaptation

Alternative technique using dual source CT imaging for assessment of myocardial perfusion

AbstractPurposeTo elucidate the diagnostic role of multidetector DSCT for the assessment of myocardial perfusion in correlation with coronary luminal integrity in a single CT scan while both tubes were operated in single energy mode.Methods and materialThirty-five patients were subjected to single acquisition contrast-enhanced, ECG-gated DSCT of the heart at rest. Postprocessing was performed generating two image sets: coronary CT angiographic images (cCTA) and myocardial perfusion images (CTP) for respective correlative assessment of coronary luminal integrity and myocardial perfusion. Perfusion defect was detected subjectively using gray scale images and the color coded first pass and color overlaid late enhancement (color attenuation) images were used for semi-objective evaluation and final objective and quantitative confirmation by density measurement.ResultsSignificant correlation and good agreement between the findings of DSCT myocardial perfusion and the findings of stenosis and its degree on cCTA on a segmental basis is noted with Cohen’s Kappa=0.67 and prevalence and bias adjusted Kappa=0.71 emphasizing the high diagnostic value of DSCT myocardial perfusion as compared to cCTA as the gold reference standard.ConclusionWe propose that comprehensive evaluation of coronary artery morphology and myocardial perfusion in patients with CAD could be achieved by single reproducible non-invasive contrast enhanced CT acquisition using DSCT scanners while operated in single energy mode with high sensitivity, specificity and diagnostic accuracy, it also has the potential to be the first, independent and stand out imaging choice in such field

Modified Bianchi pyloromyotomy versus laparoscopic pyloromyotomy for patients with infantile hypertrophic pyloric stenosis: Intraoperative considerations and parents’ satisfaction

Introduction Infantile hypertrophic pyloric stenosis is a common cause of persistent nonbilious vomiting during infancy. Ramstedt pyloromyotomy through right upper quadrant transverse incision is the conventional treatment. The laparoscopic and Tan-Bianchi approaches were introduced to improve the cosmesis and decrease postoperative morbidity. In this study, we compared between laparoscopic and modified Bianchi approaches regarding intraoperative technical considerations and postoperative outcomes.Patients and methods The study included 40 patients with infantile hypertrophic pyloric stenosis. Overall, 20 patients underwent laparoscopic pyloromyotomy (LP) and the other 20 patients underwent modified Bianchi pyloromyotomy (MBP). Patients’ characteristics, including age, sex, gestational age, and associated  comorbidities, were documented. Intraoperative details and complications and postoperative outcomes were recorded.Results The operative time and intraoperative complications including mucosal perforation and bleeding did not significantly differ between both the groups. From the laparoscopic group, one (5%) case was complicated by mucosal perforation and converted to open and another case (5%) developed hypercapnia. There was no statistically significant difference between the two groups regarding time till full feed (P=0.648) and postoperative hospital stay (P=0.082). In addition, there was no statistically significant difference between the two groups regarding postoperative complications, with one (5%) case from the laparoscopic group underwent incomplete myotomy and required redo-operation and another case (5%) developed wound infection. MBP had a significantly more parent satisfaction regarding cosmesis than LP (P=0.016).Conclusion MBP is comparable to LP regarding intraoperative complications and postoperative outcomes; however, the modified Bianchi approach offered more parent satisfaction than laparoscopic approach.  Keywords: laparoscopic, modified Bianchi, pyloric stenosis, pyloromyotom

A New Chaotic System with Line of Equilibria: Dynamics, Passive Control and Circuit Design

A new chaotic system with line equilibrium is introduced in this paper. This system consists of five terms with two transcendental nonlinearities and two quadratic nonlinearities. Various tools of dynamical system such as phase portraits, Lyapunov exponents, Kaplan-Yorke dimension, bifurcation diagram and Poincarè map are used. It is interesting that this system has a line of fixed points and can display chaotic attractors. Next, this paper discusses control using passive control method. One example is given to insure the theoretical analysis. Finally, for the  new chaotic system, An electronic circuit for realizing the chaotic system has been implemented. The numerical simulation by using MATLAB 2010 and implementation of circuit simulations by using MultiSIM 10.0 have been performed in this study

Toxoplasma gondii and Neospora caninum Antibodies in Dogs and Cats from Egypt and Risk Factor Analysis.

BACKGROUND Toxoplasma gondii and Neospora caninum are major protozoan parasites of worldwide distribution and significance in veterinary medicine and, for T. gondii, in public health. Cats and dogs, as final hosts for T. gondii and N. caninum, respectively, have a key function in environmental contamination with oocysts and, thus, in parasite transmission. Very little is known about the prevalence of T. gondii infections in dogs and cats in Egypt, and even less about the prevalence of N. caninum in the same hosts. METHODS In the current study, 223 serum samples of both dogs (n = 172) and cats (n = 51) were investigated for specific antibodies to T. gondii and N. caninum using commercially available ELISAs. A risk factor analysis was conducted to identify factors associated with seropositivity. RESULTS & DISCUSSION Exposure to T. gondii was reported in 23.3% of the dogs and in 9.8% of the cats, respectively. In addition, N. caninum-specific antibodies were recorded in 5.8% of dogs and in 3.4% of cats. A mixed infection was found in two dogs (1.2%) and in one cat (2%). Antibodies to T. gondii in dogs were significantly more frequent in dogs aged 3 years or more and in male German Shepherds. As this breed is often used as watchdogs and was the most sampled breed in Alexandria governorate, the purpose "watchdog" (compared to "stray" or "companion"), the male sex, and the governorate "Alexandria" also had a significantly higher seroprevalence for T. gondii. No factors associated with antibodies to N. caninum could be identified in dogs, and no significant factors were determined in cats for either T. gondii or N. caninum infection. Our study substantially adds to the knowledge of T. gondii infection in dogs and cats and presents data on N. caninum infection in cats for the first and in dogs in Egypt for the second time

Serum Ceramide Kinase as a Biomarker of Cognitive Functions, and the Effect of Using Two Slimming Dietary Therapies in Obese Middle Aged Females

AIM: Highlighting the impact of obesity on mental and cognitive functions using serum ceramide kinase enzyme concentration as a biomarker for cognitive evaluation in the middle aged females, and also targeting to control the obesity and simultaneously postponing the deterioration of the cognitive functions, by implementing two slimming dietary therapies each incorporating different functional ingredients known to boost cognition.SUBJECTS AND METHODS: Ninety six obese middle aged females, divided into two groups volunteered to follow a low caloric balanced diet combined with two bread supplements composed essentially of barley flour and wheat germ mixed with either 5% turmeric, group (A); or with 5% ginger, group (B) for 4 weeks, phase (1); to be followed by the hypocaloric diet alone for another 4 weeks, phase (2).RESULTS: By the end of phase (1), the biochemical analysis showed a positive response of the levels of C-peptide and modified homeostatic model assessment of insulin resistance; also increased levels of the serum ceramide kinase enzyme, coupled with improved cognitive functions tests. Improvement of the relevant metabolic profile, fasting blood glucose, blood pressure and the anthropometric measurements was detected.CONCLUSION: Using dietary therapy supported by special formulas which contain active ingredients succeeded in reducing weight and improving both the metabolic profile and the cognitive functions

Injection Drug Use Is a Risk Factor for HCV Infection in Urban Egypt

OBJECTIVE: To identify current risk factors for hepatitis C virus (HCV) transmission in Greater Cairo. DESIGN AND SETTING: A 1:1 matched case-control study was conducted comparing incident acute symptomatic hepatitis C patients in two "fever" hospitals of Greater Cairo with two control groups: household members of the cases and acute hepatitis A patients diagnosed at the same hospitals. Controls were matched on the same age and sex to cases and were all anti-HCV antibody negative. Iatrogenic, community and household exposures to HCV in the one to six months before symptoms onset for cases, and date of interview for controls, were exhaustively assessed. RESULTS: From 2002 to 2007, 94 definite acute symptomatic HCV cases and 188 controls were enrolled in the study. In multivariate analysis, intravenous injections (OR = 5.0; 95% CI = 1.2-20.2), medical stitches (OR = 4.2; 95% CI = 1.6-11.3), injection drug use (IDU) (OR = 7.9; 95% CI = 1.4-43.5), recent marriage (OR = 3.3; 95% CI = 1.1-9.9) and illiteracy (OR = 3.9; 95% CI = 1.8-8.5) were independently associated with an increased HCV risk. CONCLUSION: In urban Cairo, invasive health care procedures remain a source of HCV transmission and IDU is an emerging risk factor. Strict application of standard precautions during health care is a priority. Implementation of comprehensive infection prevention programs for IDU should be considered

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Post-vasectomy semen analysis: Optimizing laboratory procedures and test interpretation through a clinical audit and global survey of practices

Purpose: The success of vasectomy is determined by the outcome of a post-vasectomy semen analysis (PVSA). This article describes a step-by-step procedure to perform PVSA accurately, report data from patients who underwent post vasectomy semen analysis between 2015 and 2021 experience, along with results from an international online survey on clinical practice. Materials and Methods: We present a detailed step-by-step protocol for performing and interpretating PVSA testing, along with recommendations for proficiency testing, competency assessment for performing PVSA, and clinical and laboratory scenarios. Moreover, we conducted an analysis of 1,114 PVSA performed at the Cleveland Clinic’s Andrology Laboratory and an online survey to understand clinician responses to the PVSA results in various countries. Results: Results from our clinical experience showed that 92.1% of patients passed PVSA, with 7.9% being further tested. A total of 78 experts from 19 countries participated in the survey, and the majority reported to use time from vasectomy rather than the number of ejaculations as criterion to request PVSA. A high percentage of responders reported permitting unprotected intercourse only if PVSA samples show azoospermia while, in the presence of few non-motile sperm, the majority of responders suggested using alternative contraception, followed by another PVSA. In the presence of motile sperm, the majority of participants asked for further PVSA testing. Repeat vasectomy was mainly recommended if motile sperm were observed after multiple PVSA’s. A large percentage reported to recommend a second PVSA due to the possibility of legal actions. Conclusions: Our results highlighted varying clinical practices around the globe, with controversy over the significance of non-motile sperm in the PVSA sample. Our data suggest that less stringent AUA guidelines would help improve test compliance. A large longitudinal multi-center study would clarify various doubts related to timing and interpretation of PVSA and would also help us to understand, and perhaps predict, recanalization and the potential for future failure of a vasectomy.American Center for Reproductive Medicin