209 research outputs found
Induction motor load generator system using direct torque control method
Implementation of complicated tests for electrical machines usually demands special experimental setups and equipments. Getting to this target, electrical machine test benches are designed and constructed. In this paper, a direct torque controlled (DTC) load generator based on space vector modulation is proposed. To realize system performance with DTC method, classical DTC has been analyzed and is used for modelling the dynamometer. The performance of proposed dynamometer is investigated by simulating different parts of the system in SIMULINK/MATLAB environment and results are presented for several industrial load profiles
A Low Complexity Space-Time Block Codes Detection for Cell-Free Massive MIMO Systems
The new generation of telecommunication systems must provide acceptable data
rates and spectral efficiency for new applications. Recently massive MIMO has
been introduced as a key technique for the new generation of telecommunication
systems. Cell-free massive MIMO system is not segmented into cells. Each BS
antennas are distributed throughout the environment and each user is served by
all BSs, simultaneously.
In this paper, the performance of the multiuser cell-free massive MIMO-system
exploying space-time block codes in the uplink, and with linear decoders is
studied. An Inverse matrix approximation using Neumann series is proposed to
reduce the computational and hardware complexity of the decoding in the
receiver.
For this purpose, each user has two antennas, and also for improving the
diversity gain performance, space-time block codes are used in the uplink.
Then, Neumann series is used to approximate the inverse matrix in ZF and MMSE
decoders, and its performance is evaluated in terms of BER and spectral
efficiency.
In addition, we derive lower bound for throughput of ZF decoder.
The simulation results show that performance of the system , in terms of BER
and spectral efficiency, is better than the single-antenna users at the same
system. Also, the BER performance in a given system with the proposed method
will be close to the exact method.Comment: 5 pages, 4 figures, Accepted for ICEE202
SEX-SPECIFIC RESTORATION OF MK-801-INDUCED SENSORIMOTOR GATING DEFICIT BY ENVIRONMENTAL ENRICHMENT
Despite ample evidence of N-methyl-D-aspartate
(NMDA) receptor dysfunction in schizophrenia, no study
has addressed the effects of enriched environment (EE) on
sensorimotor gating deficits induced by postnatal NMDA
receptor blockade. We evaluated the effect of EE on sensorimotor gating (measured by prepulse inhibition, PPI), or on
sensorimotor gating deficit induced by the NMDA receptor
antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cy
clohepten-5,10-imine maleate (MK-801) in both sexes of
Wistar rats. Rats were injected with MK-801 (1 mg/kg) on
postnatal days (P) 6–10. EE was provided from birth up to
the time of experiments on P28–30 or P58–60. PPI data were
collected at three prepulse intensities and then averaged to
yield global PPI. MK-801 treatment reduced PPI significantly in both sexes. While EE per se had no significant
effect on PPI, it restored MK-801-induced PPI deficit only
in male rats. An extended period of EE did not influence
PPI deficit in female rats. Our results indicate that postnatal
exposure to MK-801 may exert long-lasting effects on neuronal circuits underlying sensorimotor gating. Sex-specific
modulation of such effects by EE suggests sexually dimorphic mechanisms are involved. � 2015 IBRO. Published by
Elsevier Ltd. All rights reserved
Estimation of cardiac output and pulmonary vascular resistance by contrast echocardiography transit time measurement: a prospective pilot study
Background
Studies with other imaging modalities have demonstrated a relationship between contrast transit and cardiac output (CO) and pulmonary vascular resistance (PVR). We tested the hypothesis that the transit time during contrast echocardiography could accurately estimate both CO and PVR compared to right heart catheterization (RHC). Methods
27 patients scheduled for RHC had 2D-echocardiogram immediately prior to RHC. 3 ml of DEFINITY contrast followed by a 10 ml saline flush was injected, and a multi-cycle echo clip was acquired from the beginning of injection to opacification of the left ventricle. 2D-echo based calculations of CO and PVR along with the DEFINITY-based transit time calculations were subsequently correlated with the RHC-determined CO and PVR. Results
The transit time from full opacification of the right ventricle to full opacification of the left ventricle inversely correlated with CO (r = -0.61, p \u3c 0.001). The transit time from peak opacification of the right ventricle to first appearance in the left ventricle moderately correlated with PVR (r = 0.46, p \u3c 0.01). Previously described echocardiographic methods for the determination of CO (Huntsman method) and PVR (Abbas and Haddad methods) did not correlate with RHC-determined values (p = 0.20 for CO, p = 0.18 and p = 0.22 for PVR, respectively). The contrast transit time method demonstrated reliable intra- (p \u3c 0.0001) and inter-observer correlation (p \u3c 0.001). Conclusions
We describe a novel method for the quantification of CO and estimation of PVR using contrast echocardiography transit time. This technique adds to the methodologies used for noninvasive hemodynamic assessment, but requires further validation to determine overall applicability
Effect of simultaneous exposure to occupational noise and cigarette smoke on binaural hearing impairment
In recent years, it has been postulated that cigarette smoking can aggravate noise-induced hearing loss. In this study, we aimed to assess the effect of concurrent exposure to cigarette smoke and occupational noise on binaural hearing impairment (BHI). In an analytic study on the workers of a large wagon manufacturing company in 2007, 622 male workers (252 smokers and 370 non-smokers, matched for other variables) participated and their BHI was compared. BHI was significantly higher in smokers than in non-smokers (odds ratio= 5.6, P < 0.001, 95 CI =3.4-9.4). Logistic regression confirmed this significant difference as well, and showed a direct relationship between the amount of BHI and pack/years of smoking. Cigarette smoking accompanied by exposure to workplace noise may play a role in causing binaural hearing impairment, so giving up or decreasing the amount of smoking may prevent or at least delay binaural hearing impairment, and eventually reduce its compensation costs
Characteristics of nursing homes and early preventive measures associated with risk of infection from COVID-19 in Lazio region, Italy: a retrospective case-control study
Objectives To understand which organisational-structural characteristics of nursing homes - also referred to as long-term care facilities (LTCFs) - and the preventative measures adopted in response to the pandemic are associated with the risk of a COVID-19 outbreak. Setting LTCFs in Lazio region in Italy. Design The study adopts a case-control design. Participants We included 141 facilities and 100 provided information for the study. Cases were defined as facilities reporting a COVID-19 outbreak (two or more cases) in March-December 2020; controls were defined as LTCFs reporting one case or zero. The exposures include the structural-organisational characteristics of the LTCFs as reported by the facilities, preventative measures employed and relevant external factors. Results Twenty facilities reported an outbreak of COVID-19. In binary logistic regression models, facilities with more than 15 beds were five times more likely to experience an outbreak than facilities with less than 15 beds OR=5.60 (CI 1.61 to 25.12; p value 0.002); admitting new residents to facilities was associated with a substantially higher risk of an outbreak: 6.46 (CI 1.58 to 27.58, p value 0.004). In a multivariable analysis, facility size was the only variable that was significantly associated with a COVID-19 outbreak OR= 5.37 (CI 1.58 to 22.8; p value 0.012) for larger facilities (>15 beds) versus smaller (<15 beds). Other characteristics and measures were not associated with an outbreak. Conclusion There was evidence of a higher risk of COVID-19 in larger facilities and when new patients were admitted during the pandemic. All other structural-organisational characteristics and preventative measures were not associated with an outbreak. This finding calls into question existing policies, especially where there is a risk of harm to residents. One such example is the restriction of visitor access to facilities, resulting in the social isolation of residents
Dysregulated autophagy in restrictive cardiomyopathy due to Pro209Leu mutation in BAG3
Myofibrillary myopathies (MFM) are hereditary myopathies histologically characterized by degeneration of myofibrils and aggregation of proteins in striated muscle. Cardiomyopathy is common in MFM but the pathophysiological mechanisms are not well understood. The BAG3-Pro209Leu mutation is associated with early onset MFM and severe restrictive cardiomyopathy (RCM), often necessitating heart transplantation during childhood. We report on a young male patient with a BAG3-Pro209Leu mutation who underwent heart transplantation at eight years of age. Detailed morphological analyses of the explanted heart tissue showed intracytoplasmic inclusions, aggregation of BAG3 and desmin, disintegration of myofibers and Z-disk alterations. The presence of undegraded autophagosomes, seen by electron microscopy, as well as increased levels of p62, LC3-I and WIPI1, detected by immunohistochemistry and western blot analyses, indicated a dysregulation of autophagy. Parkin and PINK1, proteins involved in mitophagy, were slightly increased whereas mitochondrial OXPHOS activities were not altered. These findings indicate that altered autophagy plays a role in the pathogenesis and rapid progression of RCM in MFM caused by the BAG3-Pro209Leu mutation, which could have implications for future therapeutic strategies
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