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Abstract High‐gain converters play a vital role in all industrial applications such as automobiles, motor drives, renewable energy systems, and railway transportation sectors. The conventional converters have low gain owing to high‐voltage stress on active MOSFET, diode and low efficiency related with high operating pulse ratio. To overcome the limitations associated with the conventional converters, this study proposes a non‐isolated configuration of multiport quasi‐resonant converter (MP‐QRC) with high gain. The proposed MP‐QRC has the merits of high‐voltage gain, reduced number of components, minimum conduction losses, realization of soft switching in the devices and improved reliability. Moreover, the proposed converter is scalable and can serve as a good candidate in microgrid environment where the integration of more than one input is essential. In this paper, first a comprehensive analysis of various operation modes and design constraints are presented. Further, the study is supported with a reliability evaluation of proposed converter based on component failure. Also, the futuristic behaviour of MP‐QRC under continuous conduction mode as a function of operational and environmental variables is investigated to ascertain the reliability. The steady‐state operation of the converter is demonstrated for off‐board electric vehilce (EV) charging using MATLAB/SIMULINK and experiments performed on a 300‐W test rig.

Joubert syndrome is a rare neurological manifestation usually present in late infancy or early childhood with characteristic episodes of abnormal breathing pattern along with the neurological and other systemic involvement.We report a case of confirmed Joubert syndrome present in the immediate neonatal period with isolated spells of oxygen desaturations not accompanied by the classically described breathing pattern and absent neurological symptoms causing delay in the diagnosis. Isolated oxygen desaturation episodes could be a presenting manifestation of Joubert syndrome in a neonatal period. [ABSTRACT FROM AUTHOR]

PURPOSE OF REVIEW: With the increasing incidence of obesity today, related complications such as diabetes, insulin resistance and hepatic steatosis are also becoming major concerns. Since these conditions share a common factor, aberrations in lipid metabolism, understanding the molecular changes that lead to abnormal lipid partitioning has become key to combating the obesity epidemic. RECENT FINDINGS: The enzyme stearoyl-coenzyme A desaturase 1 (SCD1) has been shown to be intimately involved in both the lipogenic as well as the lipid oxidative pathways. Our studies with the SCD1 mouse model have established that these animals are lean and protected from leptin deficiency-induced and diet-induced obesity. Consequently, they also show greater whole body insulin sensitivity than wild-type mice. SCD1 mice have decreased expression of genes of lipogenesis and increased expression of lipid oxidative genes. The main transcription factors controlling genes of lipid synthesis and oxidation are sterol regulatory element binding protein-1c and peroxisome proliferator-activated receptor-alpha (PPARalpha), respectively. Here, we review some studies that show that the effects of SCD1 deficiency on whole body adiposity may be partly dependent on sterol regulatory element binding protein-1c, but are most likely independent of peroxisome proliferator-activated receptor-alpha. SUMMARY: Our findings indicate that SCD1 is a key controller of lipid partitioning between lipogenesis and oxidation. While some questions regarding the molecular changes downstream of SCD1 deletion are yet to be answered, the studies outlined below clearly point to SCD1 as a highly promising target in combating obesity as well as related complications. [ABSTRACT FROM AUTHOR]

This paper presents a simple multiple-input-multiple-output (MIMO) channel model that predicts the eigenvalue distribution and hence, the capacity of MIMO systems using vertically polarized and dual-polarized transmit-antenna configurations with dual-polarized receive antennas. The channel model is verified using broadband outdoor channel measurements taken by a 2 x 3 MIMO system in the 2.5 GHz band. [ABSTRACT FROM PUBLISHER]

We use field trial results obtained from a multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) wireless system with two transmitter and three receiver antennas (2×3), to first validate the properties of the transmit correlation matrix in a macro-cellular environment. We find that approximately 20% of the locations have well-defined transmit correlation matrices. Furthermore, the eigenvectors of the transmit correlation matrix vary slowly over distance with 60% of the locations having eigenvector variation of less than 1 dB over a distance of 20 m. Next, we quantify the performance of the optimal statistical linear precoding (OSLP) , and statistical one-dimensional (1-D) eigenbeamforming (SEB) based on transmit correlation matrices, and the 1-D eigenbeamforming (EB)-based on perfect channel knowledge at the transmitter. We find that the OSLP and SEB schemes obtain array gain over the Alamouti scheme at lower signal-to-noise ratio (SNR) with a median gain of 2.0 (1.5) dB at the 1.0-(3.5) km cell-radii. However, the SEB scheme (unlike the OSLP scheme) looses diversity order at higher SNR that leads to a performance loss. The EB scheme provides the best performance over the Alamouti scheme, at the expense of increased feedback requirements. [ABSTRACT FROM PUBLISHER]

We design an optimal linear precoder for a space-time coded system assuming knowledge of only the transmit antenna fading correlations. Assuming a flat fading channel and a maximum-likelihood receiver, we show that the linear precoder transmits power on the eigenmodes of the transmit antenna correlation matrix. The power allocation on the eigenmodes is a form of waterpouring policy. Simulation results are presented to show performance improvement on a space-time coded system [ABSTRACT FROM PUBLISHER]

Objective: Occupational hazards is an area where many countries have begun to pay more emphasis as it affects the health of many particularly in developing countries. However, documented literature is scarce in this regard although occupational hazards are common in workplaces. The study was carried out with the objective of describing the physical hazards and control measures adopted in the formal medium and large-scale industrial sector in Sri Lanka. Results: Of the 69 units of the 25 factories, physical hazards detected in the workplaces were; excessive noise (78.3%), poor light (58%), increased temperature (65.2%), and poor ventilation (68.1%). Over 50% of large machinery and 33% of medium-scale machinery were not adequately guarded. Nearly 41% of the machinery were difficult to operate, of them 36.2% had controls in positions which were hard to reach. Of safety measures adopted, only 34.8% had proper demarcation of areas with 28.9% displaying safety signs. Housekeeping was poor in 59.4% and less than 40% had safe storage of raw materials and end products. [ABSTRACT FROM AUTHOR]