Speed sensorless and MPPT control of IPM synchronous generator for wind energy conversion system

The popularity of renewable energy has experienced significant growth recently due to the foreseeable exhaustion of conventional fossil fuel power generation methods and increasing realization of the adverse effects that conventional fossil fuel power generation has on the environment. Among the renewable energy sources, wind power generation is rapidly becoming competitive with conventional fossil fuel sources. The wind turbines in the market have a variety of innovative concepts, with proven technology for both generators and power electronics interfaces. Recently, variable-speed permanent magnet synchronous generator (PMSG) based wind energy conversion systems (WECS) is becoming more attractive in comparison to the fixed-speed WECS. In the variable-speed generation system, the wind turbine can be operated at maximum power operating points over a wide speed range by adjusting the shaft speed optimally. This thesis presents both wind and rotor speed sensorless control for the direct-drive interior permanent magnet synchronous generator (IPMSG) with maximum power point tracking (MPPT) algorithm. The proposed method, without requiring the knowledge of wind speed, air density or turbine parameters, generates optimum speed command for speed control loop of vector controlled machine side converter. The MPPT algorithm based on perturbation and observation uses only estimated active power as its input to track peak output power points in accordance with wind speed change and incorporates proposed sensorless control to transfer maximum dc-link power from generator. In this work for the IPMSG, the rotor position and speed are estimated based on model reference adaptive system. Additionally, it incorporates flux weakening controller (FWC) for wide operating speed range at various wind speed and other disturbances. Matlab/Simulink based simulation model of the proposed sensorless MPPT control of IPMSG based WECS is built to verify the effectiveness of the system. The MPPT controller has been tested for variable wind speed conditions. The performance of the proposed WECS is also compared with the conventional control of WECS system. The proposed IPMSG based WECS incorporating the MPPT and sensorless algorithms is successfully implemented in real-time using the digital signal processor (DSP) board DS1104 for a laboratory 5 hp machine. A 5 hp DC motor is used as wind turbine to drive the IPMSG. The speed tracking performance and maximum power transfer capability of the proposed WECS are verified by both simulation and experimental results at different speed conditions

Stress Fractures of the Elbow in the Throwing Athlete: A Systematic Review.

Background: Stress fractures of the elbow are rare in throwing athletes and present a challenge from both a management and rehabilitation perspective. Although the incidence of stress fractures of the elbow is increasing, there is a lack of data in the literature focused on throwers. Purpose: To evaluate studies regarding the management and outcomes of stress fractures of the elbow in throwing athletes. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was conducted by searching the Scopus, PubMed, and Cochrane Library electronic databases to identify studies reporting on the management and outcomes of stress fractures in overhead-throwing athletes. Management data included nonoperative and operative modalities, and outcome data included return to play, encompassing the timing and level of activity. Studies were excluded if the stress fracture of the elbow was not a result of a sport injury attributed to throwing or if the study failed to report whether an athlete returned to play. Results: Fourteen studies met the inclusion criteria and were included in this analysis. There were 52 patients in total (50 male, 2 female) with a mean age of 19.7 years (range, 13-29.1 years). The olecranon was the most common location of the stress fracture (51 patients; 98.1%), followed by the distal humerus (1 patient; 1.9%). The majority of patients (n = 40; 76.9%) were treated operatively. Of the 40 patients who were treated surgically, 14 (35.0%) underwent a period of conservative treatment preoperatively that ultimately failed because of persistent nonunion or continued elbow pain. A total of 50 patients (96.2%) returned to sport either at or above their preinjury level. Of the 2 patients (3.8%) who did not return to sport, 1 did not return because of continued elbow pain postoperatively, and the other was lost to follow-up. Complications occurred in 9 patients (17.3%), all of whom were treated surgically. Conclusion: On the basis of this systematic review, the majority of elbow stress fractures were treated operatively and approximately one-third after a period of failed nonoperative management. The return-to-sport rate was high. Further, higher level studies are needed to optimize management and return-to-sport rates in this population

Structure and permeability of ion-channels by integrated AFM and waveguide TIRF microscopy.

Membrane ion channels regulate key cellular functions and their activity is dependent on their 3D structure. Atomic force microscopy (AFM) images 3D structure of membrane channels placed on a solid substrate. Solid substrate prevents molecular transport through ion channels thus hindering any direct structure-function relationship analysis. Here we designed a ~70 nm nanopore to suspend a membrane, allowing fluidic access to both sides. We used these nanopores with AFM and total internal reflection fluorescence microscopy (TIRFM) for high resolution imaging and molecular transport measurement. Significantly, membranes over the nanopore were stable for repeated AFM imaging. We studied structure-activity relationship of gap junction hemichannels reconstituted in lipid bilayers. Individual hemichannels in the membrane overlying the nanopore were resolved and transport of hemichannel-permeant LY dye was visualized when the hemichannel was opened by lowering calcium in the medium. This integrated technique will allow direct structure-permeability relationship of many ion channels and receptors

The Association between Childhood Overweight and Reflux Esophagitis

Background. In adults, it has been shown that obesity is associated with gastroesophageal reflux disease (GERD) and GERD-related complications. There are sparse pediatric data demonstrating associations between childhood overweight and GERD. Objective. To investigate the association between childhood overweight and RE. Methods. We performed a retrospective chart review of 230 children (M : F = 114  : 116) who underwent esophagogastroduodenoscopy (EGD) with biopsies between January 2000 and April 2006. Patient demographics, weight, height, clinical indications for the procedure, the prevalence of BMI classification groups, the prevalence of RE and usage of anti-reflux medications were reviewed. For these analyses, the overweight group was defined to include subjects with BMI≥ 85th percentile. The normal weight group was defined to include subjects with BMI 5th to 85th percentile. Results. Among the 230 subjects, 67 (29.1%) had BMI percentiles above the 85th percentile for age and gender. The prevalence of RE in the overweight group did not differ significantly from that in the normal weight group (23.9% versus 24.5%, resp.). Overweight subjects taking anti-reflux medications clearly demonstrated a higher prevalence of biopsy-proven RE compared to overweight subjects not taking anti-reflux medications (34.1% versus 7.7%, P = .009). Conclusions. There was no significant difference in the prevalence of biopsy-proven RE in the overweight group compared to the normal weight group. However, the prevalence of RE was significantly higher in overweight subjects on anti-reflux medications compared to overweight subjects not taking anti-reflux medications. This finding emphasizes the importance of early recognition and treatment of GERD for the overweight pediatric patients with symptoms in conjunction with weight loss program for this population to reduce long-term morbidities associated with GERD

Large Differences in Small RNA Composition Between Human Biofluids.

Extracellular microRNAs (miRNAs) and other small RNAs are implicated in cellular communication and may be useful as disease biomarkers. We systematically compared small RNAs in 12 human biofluid types using RNA sequencing (RNA-seq). miRNAs and tRNA-derived RNAs (tDRs) accounted for the majority of mapped reads in all biofluids, but the ratio of miRNA to tDR reads varied from 72 in plasma to 0.004 in bile. miRNA levels were highly correlated across all biofluids, but levels of some miRNAs differed markedly between biofluids. tDR populations differed extensively between biofluids. Y RNA fragments were seen in all biofluids and accounted for >10% of reads in blood plasma, serum, and cerebrospinal fluid (CSF). Reads mapping exclusively to Piwi-interacting RNAs (piRNAs) were very rare, except in seminal plasma. These results demonstrate extensive differences in small RNAs between human biofluids and provide a useful resource for investigating extracellular RNA biology and developing biomarkers

Adverse drug reaction monitoring on antiretroviral therapy in human immunodeficiency virus patients in a tertiary care hospital

Background: The aim of current study was to assess the pattern of adverse drug reactions (ADRs) in patients receiving antiretroviral (ARV) therapy.Methods: A prospective, observational study was carried out for duration of 15 months. Clinical and treatment data were collected from patients, who underwent ARV therapy during the study period. CDSCO forms were used to record the ADRs. Causality, severity and preventability were assessed by suitable scales.Result: Out of 216 patients 165 (76%) patients develop ADRs. Total of 274 ADRs were noted among 165 patients (1.66 ADR/patient). Out of them 100 (60.60%) were males and 65 (39.39%) were females. The most common ADR was gastrointestinal disorders (83, 30.29%). The most numbers of ADRs were observed in ZLN (Zidovudine + Lamivudine + Nevirapine) regimen (54%) followed by SLN (Stavudine + Lamivudine + Nevirapine) regimen (26%). According to WHO causality assessment scale most ADRs were possible (236, 86.13%). Hartwig and Siegel severity scale show 243 (88.69%) ADRs were moderate. Schumock and Thornton scale show all, ADRs were “not preventable.”Conclusion: Early detection of drug toxicity helps to treat the patient and modify the drug regimen to minimize toxic effects

Orthopedic Principles to Facilitate Enhanced Recovery After Cardiac Surgery

Enhanced recovery after surgery (ERAS) protocols recognize early postoperative mobilization as a driver of faster postoperative recovery, return to normal activities, and improved long-term patient outcomes. For patients undergoing open cardiac surgery, an opportunity for facilitating earlier mobilization and a return to normal activity lies in the use of improved techniques to stabilize the sternal osteotomy. By following the key orthopedic principles of approximation, compression, and rigid fixation, a more nuanced approach to sternal precaution protocols is possible, which may enable earlier patient mobilization, physical rehabilitation, and recovery

Sooty Mangabey Genome Sequence Provides Insight into AIDS Resistance in a Natural SIV Host

In contrast to infections with human immunodeficiency virus (HIV) in humans and simian immunodeficiency virus (SIV) in macaques, SIV infection of a natural host, sooty mangabeys (Cercocebus atys), is non-pathogenic despite high viraemia. Here we sequenced and assembled the genome of a captive sooty mangabey. We conducted genome-wide comparative analyses of transcript assemblies from C. atys and AIDS-susceptible species, such as humans and macaques, to identify candidates for host genetic factors that influence susceptibility. We identified several immune-related genes in the genome of C. atys that show substantial sequence divergence from macaques or humans. One of these sequence divergences, a C-terminal frameshift in the toll-like receptor-4 (TLR4) gene of C. atys, is associated with a blunted in vitro response to TLR-4 ligands. In addition, we found a major structural change in exons 3-4 of the immune-regulatory protein intercellular adhesion molecule 2 (ICAM-2); expression of this variant leads to reduced cell surface expression of ICAM-2. These data provide a resource for comparative genomic studies of HIV and/or SIV pathogenesis and may help to elucidate the mechanisms by which SIV-infected sooty mangabeys avoid AIDS

Examining the correlates and drivers of human population distributions across low-and middle-income countries

Geographical factors have influenced the distributions and densities of global human population distributions for centuries. Climatic regimes have made some regions more habitable than others, harsh topography has discouraged human settlement, and transport links have encouraged population growth. A better understanding of these types of relationships enables both improved mapping of population distributions today and modelling of future scenarios. However, few comprehensive studies of the relationships between population spatial distributions and the range of drivers and correlates that exist have been undertaken at all, much less at high spatial resolutions, and particularly across the low-and middle-income countries. Here, we quantify the relative importance of multiple types of drivers and covariates in explaining observed population densities across 32 low-and middle-income countries over four continents using machine-learning approaches. We find that, while relationships between population densities and geographical factors show some variation between regions, theyare generally remarkably consistent,pointing to universal drivers of human population distribution. Here,we find that a set of geographical features relating to the built environment, ecology and topography consistently explain the majority of variability in population distributions at fine spatial scales across the low-and middle-income regions of the world.</p

High-resolution CT phenotypes in pulmonary sarcoidosis: a multinational Delphi consensus study

One view of sarcoidosis is that the term covers many different diseases. However, no classification framework exists for the future exploration of pathogenetic pathways, genetic or trigger predilections, patterns of lung function impairment, or treatment separations, or for the development of diagnostic algorithms or relevant outcome measures. We aimed to establish agreement on high-resolution CT (HRCT) phenotypic separations in sarcoidosis to anchor future CT research through a multinational two-round Delphi consensus process. Delphi participants included members of the Fleischner Society and the World Association of Sarcoidosis and other Granulomatous Disorders, as well as members' nominees. 146 individuals (98 chest physicians, 48 thoracic radiologists) from 28 countries took part, 144 of whom completed both Delphi rounds. After rating of 35 Delphi statements on a five-point Likert scale, consensus was achieved for 22 (63%) statements. There was 97% agreement on the existence of distinct HRCT phenotypes, with seven HRCT phenotypes that were categorised by participants as non-fibrotic or likely to be fibrotic. The international consensus reached in this Delphi exercise justifies the formulation of a CT classification as a basis for the possible definition of separate diseases. Further refinement of phenotypes with rapidly achievable CT studies is now needed to underpin the development of a formal classification of sarcoidosis