65 research outputs found

    Pre-gestational stress reduces the ratio of 5-HIAA to 5-HT and the expression of 5-HT1A receptor and serotonin transporter in the brain of foetal rat

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    <p>Abstract</p> <p>Background</p> <p>Many studies have found that stress before or during pregnancy is linked to an increased incidence of behavioural disorders in offspring. However, few studies have investigated hypothalamic-pituitary-adrenal (HPA) axis activity and the serotonergic system as a consequence of pregestational stress. In the present study, we investigated the effect of pre-gestational stress on HPA axis activity in maternal rats and their foetuses and examined whether changes in HPA axis activity of maternal rats produced functional changes in the serotonergic system in the brain of foetuses.</p> <p>Results</p> <p>We used the behavioural tests to assess the model of chronic unpredictable stress (CUS) in maternal rats. We found the activity in the open field and sucrose consumption was lower for rats with CUS than for the controls. Body weight but not brain weight was higher for control foetuses than those from the CUS group. Serum corticosterone and corticotrophin-releasing hormone levels were significantly higher for mothers with CUS before pregnancy and their foetuses than for the controls. Levels of 5-hydroxytryptamine (5-HT) were higher in the hippocampus and hypothalamus of foetuses in the CUS group than in the controls, and 5-hydroxyindoleacetic acid (5-HIAA) levels were lower in the hippocampus in foetuses in the CUS group than in the control group. Levels of 5-HIAA in the hypothalamus did not differ between foetuses in the CUS group and in the control group. The ratio of 5-HIAA to 5-HT was significantly lower for foetuses in the CUS group than in the control group. Levels of 5-HT1A receptor were significantly lower in the foetal hippocampus in the CUS group than in the control group, with no significant difference in the hypothalamus. The levels of serotonin transporter (SERT) were lower in both the foetal hippocampus and foetal hypothalamus in the CUS group than in the control group.</p> <p>Conclusions</p> <p>Our data demonstrate that pre-gestational stress alters HPA axis activity in maternal rats and their foetuses, which is associated with functional changes in 5-HT activity (5-HT, 5-HIAA and ratio of 5-HIAA to 5-HT), as well as the levels of the 5-HT1A receptor and SERT in the hippocampus and hypothalamus of foetuses.</p

    The Optimal Sine Pulse Frequency of Pulse Hydraulic Fracturing for Reservoir Stimulation

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    Pulse hydraulic fracturing (PHF) is a key technique for reservoir stimulation. PHF can well accelerate the rupture of rock. However, the supercharging mechanism of PHF is not fully understood. The main reason is that the pressure distribution and its variation, especially the peak pressure characteristics, are unclear inside the pipe and fissure. The present research focuses on the sine pulse applied at the inlet of a pipe or fracture to reveal the variation regularity of peak pressure with the pulse frequency, amplitude, pipe length, diameter and wave speed. First, the weakly compressible Navier–Stokes equations were developed to simulate the variation of fluid pressure. The computation codes were developed using the MacCormack method validated by the existing experimental data. Then, the sine pulse effect was studied inside the pipe and fissure. Last, a new frequency model was built to describe the relationship between the optimal pulse frequency, wave speed and pipe length. The results show that there is a family of frequencies at which the peak pressure of the endpoint can be significantly enhanced and that these frequencies are the optimal pulse frequency. It is found that the optimal pulse frequency depends on the pipe or fissure length and wave speed. At the optimal pulse frequency, the peak pressure at the endpoint can be increased by 100% or more, and the cavitation phenomenon occurs. However, the peak pressure decreases when with the decrease in the pipe diameter and fissure departure due to the friction drag effect of the wall. These new landmark findings are very important for the PHF technique. In addition, a new universal frequency model is built to predict the optimal sine pulse frequency. The present research shows the variation regularity of the fluid pressure inside the pipe and develops a sine frequency-controlled method, providing a potential guide for reservoir stimulation

    The Optimal Sine Pulse Frequency of Pulse Hydraulic Fracturing for Reservoir Stimulation

    No full text
    Pulse hydraulic fracturing (PHF) is a key technique for reservoir stimulation. PHF can well accelerate the rupture of rock. However, the supercharging mechanism of PHF is not fully understood. The main reason is that the pressure distribution and its variation, especially the peak pressure characteristics, are unclear inside the pipe and fissure. The present research focuses on the sine pulse applied at the inlet of a pipe or fracture to reveal the variation regularity of peak pressure with the pulse frequency, amplitude, pipe length, diameter and wave speed. First, the weakly compressible Navier&ndash;Stokes equations were developed to simulate the variation of fluid pressure. The computation codes were developed using the MacCormack method validated by the existing experimental data. Then, the sine pulse effect was studied inside the pipe and fissure. Last, a new frequency model was built to describe the relationship between the optimal pulse frequency, wave speed and pipe length. The results show that there is a family of frequencies at which the peak pressure of the endpoint can be significantly enhanced and that these frequencies are the optimal pulse frequency. It is found that the optimal pulse frequency depends on the pipe or fissure length and wave speed. At the optimal pulse frequency, the peak pressure at the endpoint can be increased by 100% or more, and the cavitation phenomenon occurs. However, the peak pressure decreases when with the decrease in the pipe diameter and fissure departure due to the friction drag effect of the wall. These new landmark findings are very important for the PHF technique. In addition, a new universal frequency model is built to predict the optimal sine pulse frequency. The present research shows the variation regularity of the fluid pressure inside the pipe and develops a sine frequency-controlled method, providing a potential guide for reservoir stimulation

    Proteomes reveal the lipid metabolic network in the complex plastid of Phaeodactylum tricornutum

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    International audiencePhaeodactylum tricornutum plastid is surrounded by four membranes, and its protein composition and function remain mysterious. In this study, the P. tricornutum plastid‐enriched fraction was obtained and 2850 proteins were identified, including 92 plastid‐encoded proteins, through label‐free quantitative proteomic technology. Among them, 839 nuclear‐encoded proteins were further determined to be plastidial proteins based on the BLAST alignments within Plant Proteome DataBase and subcellular localization prediction, in spite of the strong contamination by mitochondria‐encoded proteins and putative plasma membrane proteins. According to our proteomic data, we reconstructed the metabolic pathways and highlighted the hybrid nature of this diatom plastid. Triacylglycerol (TAG) hydrolysis and glycolysis, as well as photosynthesis, glycan metabolism, and tocopherol and triterpene biosynthesis, occur in the plastid. In addition, the synthesis of long‐chain acyl‐CoAs, elongation, and desaturation of fatty acids (FAs), and synthesis of lipids including TAG are confined in the four‐layered‐membrane plastid based on the proteomic and GFP‐fusion localization data. The whole process of generation of docosahexaenoic acid (22:6) from palmitic acid (16:0), via elongation and desaturation of FAs, occurs in the chloroplast endoplasmic reticulum membrane, the outermost membrane of the plastid. Desaturation that generates 16:4 from 16:0 occurs in the plastid stroma and outer envelope membrane. Quantitative analysis of glycerolipids between whole cells and isolated plastids shows similar composition, and the FA profile of TAG was not different. This study shows that the diatom plastid combines functions usually separated in photosynthetic eukaryotes, and differs from green alga and plant chloroplasts by undertaking the whole process of lipid biosynthesis

    Cyber-physical thermal management of 3D multi-core cache-processor system with microfluidic cooling

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    Existing three-dimensional (3D) integration of multi-core processor-cache system is confronted with the problem of die thermal run-away hazard. This teething problem is addressed by a real-time demand-based thermal management with non-uniform microfluidic cooling in this paper. A novel runtime temperature management is implemented to predict the real-time temperature demand based on software-sensing with prediction-and-correction. A 3D thermal model is developed to cater the real-time microfluidic thermal dynamics. An autoregressive (AR) prediction with correction is implemented by Kalman filtering to predict and correct the runtime power, which is further used to calculate the future temperature demand. With this software-sensing approach, thermal management can be performed in a cyber-physical fashion with real-time sensing, prediction-and-correction and fine-grained control. Compared to the existing works using on-chip temperature sensors, our closed-loop controller with software-sensing avoids the cost of sensor implementation and deployment. Our work analyzes and predicts the fine-grained temperature profile of multi-core processorcache system. It enables a number of microfluidic channels to be adjusted adaptively with different flow-rates to control the system temperature proactively as opposed to the static control with a uniform flow-rate for microfluidic channels. With the proposed cyber-physical temperature management scheme, it is shown that the temperature of multi-core system is suppressed below an acceptable thermal threshold. In fact, the fine-grained flow-rate control also achieves a more even temperature distribution and saves up to 72.1% of total flow-rate compared with uniform flow-rate controls

    The Difference between Aesthetic Appreciation of Artistic and Popular Music: Evidence from an fMRI Study

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    <div><p>To test the hypothesis that pleasure from artistic music is intellectual while that from popular music is physiological, this study investigated the different functional mechanisms between aesthetic appreciation of artistic and popular music using fMRI. 18 male non-musicians were scanned while they performed an aesthetic rating task for excerpts of artistic music, popular music and musical notes playing and singing (control). The rating scores of artistic and popular music excerpts were both significantly higher than that of control materials while the scores of them were not different. The fMRI results showed both artistic and popular conditions activated the VS and vmPFC, compared with control condition. When contrasted popular and artistic condition directly, we found popular music activated right putamen, while artistic music activated right mPFC. By parametric analysis, we found the activation of right putamen tracked the aesthetic ratings of popular music, whereas the BOLD signal in right mPFC tracked the aesthetic ratings of artistic music. These results indicate the reward induced by popular music is closer to a primary reward while that induced by artistic music is closer to a secondary reward. We also found artistic music activated ToM areas, including PCC/PC, arMFC and TPJ, when compared with popular music. And these areas also tracked aesthetic ratings of artistic music but not those of popular music. These results imply that the pleasure from former comes from cognitive empathy. In conclusion, this study gives clear neuronal evidences supporting the view that artistic music is of intelligence and social cognition involved while the popular music is of physiology.</p></div

    Horizontal and Vertical Distributions of Chromium in a Chromate Production District of South Central China

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    To study the horizontal and vertical distribution of chromium (Cr) in the soil of a chromate production site (CPS) and its nearby area (NA-CPS) in south central China, 61 profiles (depth: 14 m) in the CPS and 69 samples (topsoil) were excavated following a grid-sampling method. The geographic coordinates, elevation, and types of soil layers were recorded, and the total Cr in the soil and the total Cr and Cr(VI) in the leachate of the soil and in the groundwater were determined. Migration of Cr in surface soils may be represented in terms of a multiple linear regression equation (R2adj = 0.632). Distance, elevation, and pH are the primary factors that influence the horizontal distribution of Cr content in the surface soils, while the Cr concentration in different soil profiles mostly obeys the positive or negative binomial distributions. For a positive distribution, the Cr concentration decreases with increasing depth in the 0.0–8.0 m soil layer, under the fixing effect of soil. However, it shows an upward trend with a depth in the 8–14 m soil layer under the influence of Cr-polluted phreatic water. Under a negative distribution, Cr content is stable in the 0–6 m layer because of the influence of chromite ore processing residue mixed with miscellaneous fills, but it decreases obviously in the 6–14 m layer under the fixing effect of soil. Similar vertical distributions were observed for pH, LCr, LCr6+, and PCr6+. The decreasing amplitude of the Cr concentration for binomial distributions is mainly affected by the Cr concentration, pH, and LRCr of the soil. Moreover, PCr6+ of soil increases with pH, and the type of soil layer is the primary factor influencing LRCr in the soil profiles. Our results of the horizontal and vertical distributions of Cr could be used to guide investigations that are focused on reducing the number of samples in the horizontal and vertical directions at CPSs, and to improve risk assessments of CPSs and nearby areas

    Regions tracking increasing aesthetic ratings of popular music and artistic music.

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    <p>Regions tracking increasing aesthetic ratings of popular music and artistic music.</p
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