Effect of the ACAA1 Gene on Preadipocyte Differentiation in Sheep

Acetyl-CoA acyltransferase 1 (ACAA1) functions as a key regulator of fatty acid β-oxidation in peroxisomes by catalyzing the cleavage of 3-ketoacyl-CoA to acetyl-CoA and acyl-CoA, which participate in the extension and degradation of fatty acids. Thus, ACAA1 is an important regulator of lipid metabolism and plays an essential role in fatty acid oxidation and lipid metabolism. Our previous study findings revealed that ACAA1 is closely associated with the peroxisome proliferator-activated receptor (PPAR) signaling and fatty acid metabolism pathways, which are involved in fat deposition in sheep, leading to our hypothesis that ACAA1 may be involved in fat deposition by regulating lipid metabolism. However, the associated molecular mechanism remains unclear. In the present study, to assess the potential function of ACAA1 in sheep preadipocyte differentiation, we knocked down and overexpressed ACAA1 in sheep preadipocytes and evaluated the pattern of ACAA1 gene expression during preadipocyte differentiation by qRT-PCR. ACAA1 was significantly expressed in the early stage of adipocyte differentiation, and then its expression decreased. ACAA1 deficiency increased lipid accumulation and the triglyceride content and promoted sheep preadipocyte differentiation, whereas ACAA1 overexpression inhibited adipogenesis and decreased lipid accumulation and the triglyceride content. Simultaneously, we demonstrated that ACAA1 deficiency upregulated the expressions of the adipogenic marker genes PPARγ and C/EBPα in sheep preadipocytes, but ACAA1 overexpression inhibited the expressions of these markers, indicating that ACAA1 affects lipid metabolism by regulating adipogenic marker genes. Our results may promote a better understanding of the regulation of adipogenesis by ACAA1

The Optimal combination: Grammatical Swarm, Particle Swarm Optimization and Neural Networks.

Social behaviour is mainly based on swarm colonies, in which each individual shares its knowledge about the environment with other individuals to get optimal solutions. Such co-operative model differs from competitive models in the way that individuals die and are born by combining information of alive ones. This paper presents the particle swarm optimization with differential evolution algorithm in order to train a neural network instead the classic back propagation algorithm. The performance of a neural network for particular problems is critically dependant on the choice of the processing elements, the net architecture and the learning algorithm. This work is focused in the development of methods for the evolutionary design of artificial neural networks. This paper focuses in optimizing the topology and structure of connectivity for these networks

Limb development genes underlie variation in human fingerprint patterns

Fingerprints are of long-standing practical and cultural interest, but little is known about the mechanisms that underlie their variation. Using genome-wide scans in Han Chinese cohorts, we identified 18 loci associated with fingerprint type across the digits, including a genetic basis for the long-recognized “pattern-block” correlations among the middle three digits. In particular, we identified a variant near EVI1 that alters regulatory activity and established a role for EVI1 in dermatoglyph patterning in mice. Dynamic EVI1 expression during human development supports its role in shaping the limbs and digits, rather than influencing skin patterning directly. Trans-ethnic meta-analysis identified 43 fingerprint-associated loci, with nearby genes being strongly enriched for general limb development pathways. We also found that fingerprint patterns were genetically correlated with hand proportions. Taken together, these findings support the key role of limb development genes in influencing the outcome of fingerprint patterning

Design, Control, and Test of Emerging Grid-connected Converters Considering Grid Requirements

Power electronics plays a significant and non-substitutable role in the power system\u27s ongoing revolution from the traditional centralized model to a decentralized system. However, many challenges need to be addressed, and this dissertation aims at addressing some of the challenges in power electronics-based grid applications. To systematically evaluate the benefits of using medium voltage (MV) silicone carbide (SiC) devices in grid applications, benchmark design comparisons are conducted considering different grid applications, voltage levels, and power ratings. The impact of grid requirements on MV SiC-based grid-connected converters is evaluated in a 13.8 kV/ 1 MW grid-connected converter design. Then, a 13.8 kV / 100 kW grid-connected converter prototype is designed and developed following the same design consideration. The converter performances and grid-side functions are tested with the designed MV test platform. An insulation structure is proposed for the MV filter inductor, which helps to shrink the overall inductor size and still maintain the grid insulation requirements. The grounding and parasitic capacitance impact on the MV device dynamic characterization and the converter power loss are analyzed. Approaches are proposed to reduce the power loss introduced by the parasitic capacitance loss of the MV transformer and the MV inductor. To test the electrical performance of the flexible combined heat and power (CHP) system and the controller, a power electronics-based test platform is designed and developed. Different grid conditions, system mode transitions, system central controller, and the system performance during both the steady state and transients are tested. To improve the low overcurrent capability of inverter-based resources (IBRs) and solve the corresponding issues, a grid strengthening IBR, combining an IBR and a co-located synchronous condenser, and its control are proposed. The proposed setup can provide comparable overcurrent capability as a synchronous generator, which is verified in the steady-state operation, single-unit operation considering different grid fault conditions, multi-unit operation, and transient stability performance. Also, it is concluded that the proposed setup does not have the transient stability issue

Simulation Research on Ventilation Control of Gaseous Pollutants in Urban Sentry Boxes

The tiny spaces of sentry boxes in cities, such as mobile security guards, highway toll booths, etc., are mostly located beside roads with harsh outdoor environments. Due to office demands, work windows often need to be kept or frequently opened. The intrusion of outdoor pollutants through the windows leads to the deterioration of the indoor air quality, and threatens the health of employees. This paper takes the gaseous pollutant NO2 as the representative and discusses the effective ventilation design scheme for improving the air quality in the sentry box with openings using two attached ventilation modes as the carrier. Taking the vertical wall-attached ventilation as an example, the formation of the air curtain at the window hole and its barrier performance to outdoor pollutants were studied. The conclusion is that when the air supply velocity is sufficient to form a complete air curtain at the window hole, it can effectively block the pollutants. The horizontal wall-attached ventilation shows that clean air is delivered to the space with openings, and the indoor air quality can also be well improved due to the dilution effect, but the effect of positive pressure control is not obvious due to the large opening. The conclusions can provide guidance for the ventilation design of sentry boxes with openings

Column-Attached Airflow Fields Created by Multi-slot in Single Ring

Researchers have shown increasing interest in attachment ventilation due to its high ventilation efficiency and good thermal comfort. To meet the ventilation performance and engineering design challenges of Circular Column Attached Ventilation (CCAV) mode due to low ventilation rates, large-diameter cylinders, and installation too high at the top of large spaces. This paper proposes a novel ventilation mode known as Column-attached ventilation with Multi-slot in Single Ring (MCAV). Through measurement of air velocity and computational fluid dynamics simulation, the air distribution characteristics of the MCAV were studied. The findings show that MCAV and CCAV have similar trends of maximum velocity decay in the vertical attachment region. The MCAV has a 10.48% higher average value of dimensionless axial velocity in the horizontal air reservoir region than the CCAV. Besides, the flow pattern envelope surface and the velocity non-uniform coefficient were introduced to verify ventilation performance. The current study helps understand a new air distribution and is used as a reference for Attachment Ventilation design

Modeling and Emulation of a Synchronous Generator Considering Unbalanced Load Conditions

Power electronics converters can be applied as emulators to mimic different grid components used for system behavior analyses and control validation. Synchronous generators (SGs) are the major sources of electric grids. Converter-based SG emulators have been developed for system stability analysis, fault analysis, and frequency support. However, existing SG emulators have not considered the impacts of load unbalance, which is a common phenomenon in distribution grids and will lead to system-level issues. In this article, a SG emulator considering an actual SG's negative sequence (NS) performance is developed for system analyses under unbalanced load conditions. With different simplifications, a SG can have different orders of electrical models. By deriving the NS performances of different SG electrical models, an appropriate SG electrical model in unbalanced load conditions is selected. Then a novel control diagram is proposed to ensure that the NS performances of the selected model can be fully realized. The derived NS models and the proposed control diagram are verified through simulation first and then validated with a converter-based hardware testbed

Performance Evaluation of An Innovative Column Attachment Ventilation

An innovative column attachment ventilation (CAV) was proposed for heating, ventilating and air-conditioning (HVAC) systems and its performance was evaluated through experimental investigation and numerical modeling. Airflow pattern, air temperature distribution, air diffusion performance index (ADPI), predicted mean vote (PMV), and draught rate (DR), were used as the performance indicators to investigate the air distribution performance. The ventilation effectiveness for heat removal in the CAV mode was compared with a conventional mixing ventilation (MV). The results showed that the discharged air from the linear slot diffuser can attach to the column and enter into the occupied zone creating air lake phenomenon. The airflow spread over the floor in a radial pattern behaved as a stratified air distribution like displacement ventilation (DV), providing good air quality and comfort level for occupants. Moreover, the heat removal effectiveness in the CAV was found to be higher than in the MV, i.e. 1.32 in the C-CAV and 1.29 in the S-CAV modes. The column attachment ventilation can achieve thermal comfort in the occupied zone without local discomfort caused by high vertical temperature difference and draught, and this ventilation strategy could be expected as a new and efficient air distribution pattern for different HVAC applications

Measurement and evaluation of indoor air quality in naturally ventilated residential buildings

This paper presents the field measurement and evaluation of the indoor air quality of 25 naturally ventilated residential buildings in northwestern China. Concentrations of formaldehyde, benzene, toluene, total volatile organic compounds, nitrogen dioxide and PM2.5, and air infiltration rate were measured in the bedroom, living room and kitchen of each building in different seasons. The results show that the concentration of formaldehyde can be used as a representative index of indoor gaseous pollutants, and that formaldehyde concentrations in various locations measured were highest in spring and lowest in autumn. PM2.5 concentration was the most important influencing factor of indoor air quality in winter, and concentration of outdoor PM2.5 was the key factor under hazy weather conditions. The median air infiltration rate was around 0.35 h-1 in bedrooms and 0.8 h-1 in kitchens, and these should be increased to 0.66 h-1 and 1.6 h-1 , respectively, to provide acceptable indoor air quality in northwestern China. The findings obtained from this study can be used to understand where and how to improve the indoor air quality of naturally ventilated buildings in northwestern China. The data can also contribute to the development of a national database for improving residential ventilation, energy efficiency and indoor air quality