38 research outputs found

    Clinical characteristics of cognitive deficits in major depressive disorder: a 6-month prospective study

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    Background: Previous studies have shown that major depressive disorder (MDD) is associated with a variety of cognitive deficits, which can persist even in remitted states. Nevertheless, the relationship between the cognitive and affective symptoms in depression remains obscure. The aim of the present study was to explore the clinical characteristics and correlates of the cognitive deficits in patients with MDD. Methods: Clinical and neuropsychological assessments were conducted at baseline and 6-month follow-ups. The severity of the disease and the effect of treatment were assessed with the Hamilton Depression Scale-17. Neuropsychological tests, including the digital symbol substitution test and digit span test, were administered to 67 depressed patients and 56 healthy participants. Results: MDD patients showed impairments in memory, attention, and executive function at baseline. After the 6-month treatment phase, patients in remission showed significant alleviation of these cognitive deficits, although impairments in attention and executive function were still present when compared to controls. Discussion: Significant cognitive deficits are present in MDD. The speed of remission of cognitive functions seems to be slower than and inconsistent with emotional symptoms, which provides new support for the argument that cognitive deficits are independent factors from the emotional symptoms in MDD

    Histopathological Features and Composition of Gut Microbiota in Rhesus Monkey of Alcoholic Liver Disease

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    Alcohol-induced chronic liver disease (ALD) is becoming the most common liver disease in the world. However, there are no effective, universally accepted therapies for ALD. The etiology of ALD remains blurry so far. Historical evidence has demonstrated a link between the liver and gut microbiota. But it is difficult to distinguish the effect of gut microbiota changes caused by alcohol consumption in humans since the microbiota change detected in humans is complicated by diet and environmental factors. Due to the genetic, physiological, metabolic, and behavioral similarities to humans, the rhesus monkey provides excellent translational validity in preclinical studies, and the diet and environmental conditions can be controlled well in rhesus monkey. In our study, we explored the relationship between ALD and the gut microbiome in the rhesus monkeys with alcoholic liver steatosis. Our results showed that there was a change of the bacterial community structure in monkeys with ALD. Differences of the relative abundances of gut microbiota at phylum, order, family, genus, and species levels were observed between control monkeys and monkeys with ALD, and different pathways enriched in the monkeys with ALD were identified by metagenomic function analysis. Firmicutes, Proteobacteria, Verrucomicrobia tended to increase whereas Bacteroidetes and Actinobacteria decreased in the fecal microbiota of ALD group compared to the control group. Lactobacillales and Lactobacillus significantly decreased in ALD monkeys compared with normal monkeys, Streptococcus was lower in the ALD group compared with the control group. The non-human primate model of ALD will be useful for exploration of the microbiome markers as diagnosis and potentially prognosis for ALD. The ALD model will benefit the development of new therapeutic procedures for treating ALD and provide safety and efficacy evaluation for clinical application

    A novel three-phase AC/DC converter without front-end filter based on adjustable triangular-wave PWM technique

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    Single-phase diode rectifier with novel passive filter

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    Two-Stage Battery Energy Storage System (BESS) in AC Microgrids with Balanced State-of-Charge and Guaranteed Small-Signal Stability

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    In this paper, a two-stage battery energy storage system (BESS) is implemented to enhance the operation condition of conventional battery storage systems in a microgrid. Particularly, the designed BESS is composed of two stages, i.e., Stage I: integration of dispersed energy storage units (ESUs) using parallel DC/DC converters, and Stage II: aggregated ESUs in grid-connected operation. Different from a conventional BESS consisting of a battery management system (BMS) and power conditioning system (PCS), the developed two-stage architecture enables additional operation and control flexibility in balancing the state-of-charge (SoC) of each ESU and ensures the guaranteed small-signal stability, especially in extremely weak grid conditions. The above benefits are achieved by separating the control functions between the two stages. In Stage I, a localized power sharing scheme based on the SoC of each particular ESU is developed to manage the SoC and avoid over-charge or over-discharge issues; on the other hand, in Stage II, an additional virtual impedance loop is implemented in the grid-interactive DC/AC inverters to enhance the stability margin with multiple parallel-connected inverters integrating at the point of common coupling (PCC) simultaneously. A simulation model based on MATLAB/Simulink is established, and simulation results verify the effectiveness of the proposed BESS architecture and the corresponding control diagram

    A Novel High Efficiency Quasi-Resonant Converter

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    In this paper, a new constant-frequency quasi-resonant converter is proposed. Compared with the traditional LLC converter, the proposed converter can effectively reduce the range of the operating frequency. The output voltage is changed to adjust the reactance of the resonant cavity. The proposed converter has a better loss factor. To verify the theoretical analysis and soft-switching condition, a 250 W, 100 V output prototype was built and compared with the full-bridge LLC converter. Analysis and experimental results verify that a smaller operating frequency range and volume of the transformers, a soft-switching condition, and a higher overall efficiency are achieved with the proposed converter

    Two-Stage Battery Energy Storage System (BESS) in AC Microgrids with Balanced State-of-Charge and Guaranteed Small-Signal Stability

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    In this paper, a two-stage battery energy storage system (BESS) is implemented to enhance the operation condition of conventional battery storage systems in a microgrid. Particularly, the designed BESS is composed of two stages, i.e., Stage I: integration of dispersed energy storage units (ESUs) using parallel DC/DC converters, and Stage II: aggregated ESUs in grid-connected operation. Different from a conventional BESS consisting of a battery management system (BMS) and power conditioning system (PCS), the developed two-stage architecture enables additional operation and control flexibility in balancing the state-of-charge (SoC) of each ESU and ensures the guaranteed small-signal stability, especially in extremely weak grid conditions. The above benefits are achieved by separating the control functions between the two stages. In Stage I, a localized power sharing scheme based on the SoC of each particular ESU is developed to manage the SoC and avoid over-charge or over-discharge issues; on the other hand, in Stage II, an additional virtual impedance loop is implemented in the grid-interactive DC/AC inverters to enhance the stability margin with multiple parallel-connected inverters integrating at the point of common coupling (PCC) simultaneously. A simulation model based on MATLAB/Simulink is established, and simulation results verify the effectiveness of the proposed BESS architecture and the corresponding control diagram

    Inflation, operating cycle, and cash holdings

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    A corporate cash-holding strategy is a trade-off between the costs and benefits of holding cash. At the macrolevel, firms are inclined to adjust and optimize their cash-holding strategies in response to changes in purchasing power due to inflation. At the microlevel, the operating cycle, which indicates the speed and turnover of corporate cash flow, also influences the corporate cash-holding strategy. Firms flexibly adjust their cash-holding strategies in response to changes in the internal and external environment, which is referred to as the cash adjustment strategy. We examine these predicted relationships using a sample of listed firms in China’s stock market over the 1998–2009 period. Consistent with our predictions, the empirical results indicate a significant negative association between cash holdings and the CPI, but the relationship is reversed when the CPI reaches a certain level. There is also a U-shaped relationship between operating cycle and cash holdings, and this relationship is similarly influenced by changes in the inflation level. In examining the macroeconomic environment and microlevel firm-specific characteristics simultaneously, our findings supplement the literature on firms’ cash-holding strategies and provide theoretical and practical implications
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