A dose-response experiment was conducted to investigate the impacts of dietary threonine (Thr) levels on growth performance, serum biochemical indices, antioxidant capacities, and gut morphology of ...broiler chickens. Four hundred and thirty-two 1-d-old commercial broilers were allocated to 4 treatments consisting of 6 replicates of 18 birds. The experimental treatments received the same Thr-deficient basal diet and were labeled as follows: 85%, 100%, 125%, and 150% of NRC (1994) recommendations. The results demonstrated that on 21 d and 42 d, average daily weight gain (ADG, 22 to 42 d, 0 to 42 d) increased quadratically or cubically as the inclusion of Thr increased, while feed conversion ratio (FCR, 0 to 21 d, 0 to 42 d) decreased quadratically or cubically as dietary Thr increase from 85% to 150%. Excess dietary Thr levels triggered plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities. The concentrations of total protein (TP) and globulin (GLO) increased quadratically with increasing Thr level, and the highest concentrations of TP and GLO were obtained at the 125% Thr level. Moreover, the plasma uric acid (UA) concentration decreased linearly or quadratically with the increase in dietary Thr level. Likewise, the serum glutathione peroxidase (GSH-Px) and total superoxide dismutases (T-SOD) activities increased quadratically as dietary Thr increased, and the highest activity of GSH-Px was obtained at the 125% Thr level, while the highest T-SOD level occurred in the 100% Thr group. Gut morphology of birds showed significant response to different graded concentrations of Thr level. Villus height (VH), crypt depth (CD), and VH:CD ratio (VH/CD) were increased linearly or quadratically by Thr supplementation. Therefore, the present study suggests that the NRC (1994) recommendations Thr level that was optimum for growth performance, and 125% of the NRC (1994) recommendations Thr level had better effects on biochemical indices, antioxidant function, and gut morphology of broilers.
Room temperature magnetic refrigeration is a new highly efficient and environmentally protective technology. Although it has not been maturely developed, it shows great applicable prosperity and ...seems to be a substitute for the traditional vapor compression technology. In this paper, the concept of magnetocaloric effect is explained. The development of the magnetic material, magnetic refrigeration cycles, magnetic field and the regenerator of room temperature magnetic refrigeration is introduced. Finally some typical room temperature magnetic refrigeration prototypes are reviewed.
Abstract One challenge in aging research concerns identifying physiological parameters or biomarkers that can reflect the physical health of an animal and predict its lifespan. In C. elegans , a ...model organism widely used in aging research, motor deficits develop in old worms. Here we employed machine vision to quantify worm locomotion behavior throughout lifespan. We confirm that aging worms undergo a progressive decline in motor activity, beginning in early life. Importantly, the rate of motor activity decline rather than the absolute motor activity in the early-to-mid life of individual worms in an isogenic population inversely correlates with their lifespan, and thus may serve as a lifespan predictor. Long-lived mutant strains with deficits in insulin/IGF-1 signaling or food intake display a reduction in the rate of motor activity decline, suggesting that this parameter might also be used for across-strain comparison of healthspan. Our work identifies an endogenous physiological parameter for lifespan prediction and healthspan comparison.
The series-parallel resistance method is based on the model configured with two hemispheres and cylindrical water framework. According to the physical parameters of the rock-soil, the effective ...thermal conductivity can be obtained with the thermal resistances of different parts.
Display omitted
•Series-parallel method is developed to predict rock-soil thermal conductivity.•Model is configured with two hemispheres and cylindrical water framework.•Results are validated with 74 tested and predicted results of rock-soil samples.•Influence factors on thermal conductivity and prediction accuracy are analyzed.
The estimation of the underground rock-soil thermal conductivity from different depths is of great importance for the studies on the performance prediction and evaluation of geothermal utilization systems. Based on the authors’ previous work on the prediction of rock-soils with moderate porosities (0.2146 <n < 0.4764), this study presents a series-parallel thermal resistance method based thermal conductivity model for the rock-soils with different constituents and water contents at low (n < 0.2146) or high porosity (n> 0.4764). The arrangement of different phases in the cubic cell element is introduced, and the thermal resistance for each part is theoretically derived to achieve the expression of the effective thermal conductivity. After verified by 74 experimentally measured and predicted results of rock-soil sample thermal conductivities in the existing work, the newly proposed method is validated to be successful to predict the rock-soil thermal conductivity with an average RMSE of 0.1289, which implies that the present model configured with two hemispheres and cylindrical water framework and based on the series-parallel resistance method provides an accurate prediction on the thermal conductivity of the rock-soils with different constituents and water contents at low or high porosity.
Aims/hypothesis
Liver X receptors (LXR) are important transcriptional regulators of lipid and glucose metabolism. Our previous report demonstrated that LXR activation inhibited pancreatic beta cell ...proliferation through cell cycle arrest. Here we explore the role of LXR activation in beta cell insulin secretion and the underlying mechanism that might be involved.
Methods
Mouse pancreatic islets or insulin-secreting MIN6 cells were exposed to the LXR agonist, T0901317, and insulin secretion, glucose and fatty acid oxidation, and lipogenic gene expression were assessed. The unsaturated fatty acid eicosapentaenoic acid and the dominant negative sterol regulatory element binding protein 1c (SREBP1c) were used to inhibit endogenous SREBP1c and evaluate the involvement of SREBP1c in beta cell dysfunction induced by LXR activation.
Results
Treatment with the LXR agonist decreased beta cell glucose sensitivity and impaired glucose-stimulated insulin secretion in vivo and in vitro. This was accompanied by derangements of beta cell glucose oxygen consumption, glucose oxidation, ATP production and intracellular voltage-gated calcium channel flux. LXR activation also regulated the expression of lipid metabolism-related genes such as
Fas
,
Acc
(also known as
Acaca
) and
Cpt1a
, and led to intracellular lipid accumulation. Further studies revealed that inhibition of SREBP1c abolished LXR activation-induced lipid accumulation and improved beta cell glucose metabolism, ATP production and insulin secretion.
Conclusions/interpretation
Our data reveal that aberrant activation of LXR reproduced the phenomenon of beta cell dysfunction in the development of type 2 diabetes in vitro and in vivo. Upregulation of SREBP1c production and the lipotoxicity mediated by it played a central role in this process.
As one kind of the basic insulating materials, polyimide has been widely used in turn to turn insulation and turn to ground insulation in inverter-fed motors. However, the pulse voltage from the ...converter often causes overvoltage and localized high electrical field in the insulation system. During applying the pulse voltage, charges accumulate on the surface of the insulator, which could affect the dielectric property and cause the breakdown of insulation. Direct fluorination is a method to modify the surface layer of the polymers without changing the bulk properties. As a result of the fluorination, hydrogen atoms are replaced by the fluorine atoms and the component of the polymer surface is changed, which can influence the surface charge accumulation and affect the electrical properties. The experiment in this paper was focused on the effect of pulse duration and pulse number on surface charge of the polyimide films. The polyimide films with the fluorination time of 0, 15, 45 and 60 min were prepared. Surface charging was performed by corona discharging using repetitive pulse power at the temperature of 20 °C with the relative humidity of ~15%. The repetition frequency was 1 kHz and the pulse duration was 50, 110 and 210 μs, respectively. The surface charge decay was measured using a specific probe coupled with an electrostatic voltmeter. The results showed that the surface charge increases with increasing the pulse number and the duration of the microsecond pulse.
BACKGROUND
Chemokine CXCL8 (also known as IL-8) has been identified as a potential regulator of endometrial stromal cells (ESCs), but it is unclear how CXCL8 regulates the survival of ESCs in the ...pathogenesis of endometriosis.
METHODS
We assessed the secretion of CXCL8 by enzyme-linked immunosorbent assays and the expression of its receptors, CXCR1 and CXCR2, by in-cell Western assay and immunhistochemistry. The effects of CXCL8 on the activation or expression of various cell mediators were also investigated by in-cell Western assay. The effects of CXCL8 on the proliferation, growth and apoptosis of ESCs in vitro were assessed by BrdU assays, cell counts and annexin V labeling, respectively.
RESULTS
Secretion of CXCL8 and expression of CXCR1 in the eutopic ESCs from women with endometriosis were significantly higher than that in control ESCs, but the expression of CXCR2 showed no significant difference between these two cell types. CXCL8 stimulated proliferation and growth and reduced apoptosis of ESCs in an autocrine manner, and these effects were abolished by anti-human CXCL8 and CXCR1 neutralizing antibodies and by a PI3K/Akt inhibitor. Moreover, CXCL8 up-regulated the expression of the anti-apoptotic proteins, survivin and Bcl-2, inhibited the expression of the Phosphatase and tensin homolog (PTEN) and activated the phosphorylation of Akt.
CONCLUSIONS
This study suggests that CXCL8 and CXCR1 are involved in the pathogenesis of endometriosis by up-regulating proliferation and growth and restricting apoptosis in ESCs by activating the PTEN/Akt pathway and mediating the expression of survivin and Bcl-2.
Abstract
For the gatling weapon, due to its high firing rate and the complex characteristics of recoil, reducing the recoil resistance and enhancing firing precision becomes an important research ...topic for the improvement of the performance of gatling weapon system. In this paper, a spring-hydraulic floating buffer device was designed as the whole gun buffer. Based on the computational fluid dynamics numerical analysis method, a calculation model of the hydraulic buffer in the gun was established. ADAMS was used to simulate the buffer, and the recoil force of automata was obtained. By comparing the simulation results with the actual test results, the correctness of the calculation and simulation methods is verified, and a technical route combining simulation calculation and test is obtained, which lays a foundation for the practical engineering application and the hydraulic buffer design.
To investigate the differences and applicability of free silica detection methods of different crystal forms in dust, and to provide a basis for the selection of various methods.
From December 2021 ...to June 2022, dust samples from 20 enterprises in different industries in 18 cities in Henan Province were randomly selected as the investigation objects. X-ray diffraction (XRD) method was used to analyze the samples and classify the samples. Based on GBZ/T 192.4-2007 "Determination of Dust in the Air of Workplace-Part 4: Content of Free Silica in Dust", pyrophosphate method and infrared spectrophotometry were used for quantitative determination. The measured results were analyzed by paired sample
test to evaluate the advantages and disadvantages of the two methods and their applicable scope.
The XRD results of 20 dust samples could be divided into α, β, γ crystal types and the mixed type of α and γ. There was no significant difference between pyrophosphate method and infrared spectrophotometry (
=0.180). The pyro
Purpose of the present study was to evaluate the effect of surface roughness on the time-dependent wear performance of lithium disilicate (LD) glass-ceramic.
Friction pairs (pin and disk specimens) ...were prepared by IPS e.max® Press lithium disilicate glass-ceramic. The lateral faces of friction pairs (N = 12) were grinded with silicon carbide papers, and 6 friction pairs were polished with a 0.25 μm diamond suspension after grinding. The friction pairs were tested for wear performance using a pin-on-disk tribometer with 10 N for 1.02 × 106 wear cycles in artificial saliva. Wear analysis of the pin and disk was performed with a 3D profilometer. The microstructure and worn surface morphology were examined with scanning electron microscopy. One-way analysis of variance and Tukey's post-hoc pairwise comparison were used to analyze the wear data.
The two group LD friction pairs presented strong time-dependent wear performance. The polished group (GP) exhibited a high wear rate and extensive surface wear during 0–1 × 105 cycles (running-in wear stage). The wear rate, height loss and surface roughness were obviously lower than those of grinded group (GG) in running-in wear stage. However, these wear parameters were similar during the steady wear stage. The worn surface topographies of the pin and disk in GP were smoother at the same cycle before the GG entering the steady wear stage.
Running-in, which means the initial stage of wear process, is a critical period to determine the final wear loss and surface degradation, when compare the wear behavior of lithium disilicate ceramic with different initial surface states. Ceramic layer with smooth contact area leads to low wear rate and short running-in wear stage.
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