45 research outputs found
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Mitochondria-Localized Glutamic Acid-Rich Protein (MGARP) Gene Transcription Is Regulated by Sp1
Background: Mitochondria-localized glutamic acid-rich protein (MGARP) is a novel mitochondrial transmembrane protein expressed mainly in steroidogenic tissues and in the visual system. Previous studies showed that MGARP functions in hormone biosynthesis and its expression is modulated by the HPG axis. Methodology/principal findings: By bioinformatics, we identified two characteristic GC-rich motifs that are located proximal to the transcription start site (TSS) of MGARP, and each contains two Specificity protein 1 (Sp1) binding elements. We then determined that the −3 kb proximal MGARP promoter is activated in a Sp1-dependent manner using reporter assays and knockdown of Sp1 led to decreased expression of endogenous MGARP messages. We also demonstrated that one of the two GC-rich motifs, GC-Box1, harbors prominent promoter activity mediated by Sp1, and that it requires both GC boxes for full transcriptional activation. These findings suggest a dominant role for these GC boxes and Sp1 in activating the MGARP promoter through a synergistic mechanism. Consistently, the results of an Electrophoretic Mobility Gel Shift Assay (EMSA) and Chromatin Immunoprecipitation (ChIP) confirmed that Sp1 specifically interacts with the GC-rich region. We further found that estrogen receptor α (ERα), a known Sp1 co-activator, could potentiate GC-boxes containing MGARP promoter activity and this effect is mediated by Sp1. Knockdown of Sp1 significantly diminished the MGARP promoter transactivation and the expression of endogenous MGARP mediated by both Sp1 and ERα. Conclusions/significance: The present study identified a proximal core sequence in the MGARP promoter that is composed of two enriched Sp1 binding motifs and established Sp1 as one major MGARP transactivator whose functions are synergistic with ERα, providing a novel understanding of the mechanisms of MGARP gene transcriptional regulation
Effect of Ga on the Inoxidizability and Wettability of Sn-0.5Ag-0.7Cu-0.05Pr Solder
The effect of trace amount of Ga on the inoxidizability and wettability of Sn-0.5Ag-0.7Cu-0.05Pr solders was investigated systematically by means of microstructure characterizations. The results indicate that the wettability and oxidation resistance properties are remarkably improved with addition of trace amount of Ga. Moreover, it is observed that the trace amount of Ga in Sn-0.5Ag-0.7Cu-0.05Pr solders refines the matrix microstructure. The relationship between wettability and oxidation resistance was put into deep study. And Ga was found to be enriched on the surface of the molten solder, which benefited the properties correspondingly. The results of this study can stimulate the use of low-silver Sn-Ag-Cu-Pr solders for various applications
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A data schema for exchanging information between urban building energy models and urban microclimate models in coupled simulations
Understanding and quantifying the interactions between urban microclimate and urban buildings is essential to improve the urban environment and building performance, especially during heatwaves. Most previous studies used tool or application specific data exchange mechanisms that cannot be generalized for other tools or applications. In this paper, we introduce a new flexible and tool-agnostic data schema to facilitate the exchange of data between urban building energy models and urban microclimate models. The JSON schema was tested using a district of 97 buildings in San Francisco and running simulations with CityBES and CityFFD as the urban building energy and microclimate modeling platforms, respectively. Compared with simulation results using the historical weather data, simulation results considering interactions between two models over a two-day heatwave event showed a 5.3°C higher average peak building facade temperature, an 8.9 °C higher average peak air node temperature, and a 19.5% higher peak cooling energy use
Belowground net primary productivity and biomass allocation in response to different restoration measures in a salt-alkali-degraded Songnen meadow
The understanding of belowground productivity restoration and biomass allocation is especially important for the restoration of salt-alkali-degraded meadows. Despite this, it remains unclear how belowground net primary productivity (BNPP) and biomass allocation respond to combined restoration measures. To assess the effects of different combined restoration measures on BNPP and biomass allocation, a field experiment was carried out in a salt-alkali-degraded meadow from 2012 to 2014. The restoration treatments included: free grazing (FG), enclosure with no-ploughing (E), enclosure with ploughing alone (EP), enclosure with ploughing and N addition (EPF), enclosure with ploughing and mulching (EPM), and enclosure with ploughing plus both N addition and mulching (EPFM). Our results across all three years showed that relative to FG, all the other restoration measures, whether single or combined, significantly increased aboveground net primary productivity (ANPP), BNPP and net primary productivity (NPP). The response of BNPP to different restoration measures was stronger than the ANPP response, resulting in a higher root fraction. The trends were clearer in the EPF, EPM and EPFM treatments, suggesting that more C was allocated to belowground roots with N addition and mulching. The strong increases in NPP and BNPP and belowground biomass allocation in the EPF, EPM and EPFM treatments were mainly due to significant increases in the density of important species (e.g. Chloris virgata and Puccinellia tenuiflora) and soil moisture, and strong decreases in soil pH and EC. Our findings demonstrate that vegetation cover, species richness and productivity (ANPP + BNPP) should be considered as important indicators when evaluating the recovery of severely degraded grassland. Our results further suggest that the combined measures, including enclosure and ploughing plus N addition and mulching, are effective ways to accelerate restoration in salt-alkali-degraded meadows
Ternary Heterojunction Graphitic Carbon Nitride/Cupric Sulfide/Titanium Dioxide Photoelectrochemical Sensor for Sesamol Quantification and Antioxidant Synergism
Sesamol (SM) is a potent natural antioxidant that can quench free radicals and modulate the cholinergic system in the brain, thereby ameliorating memory and cognitive impairment in Alzheimer’s disease patients. Moreover, the total antioxidant capacity can be amplified by synergistic interactions between different antioxidants. Here, we constructed a ternary heterojunction graphitic carbon nitride/cupric sulfide/titanium dioxide (g-C3N4/CuS/TiO2) photoelectrochemical (PEC) sensor for the quantification of SM and its synergistic interactions with other antioxidants. Crucially, the Schottky barrier in ternary semiconductors considerably enhances electron transfer. The PEC sensor showed a wide linear range for SM detection, ranging from 2 to 1277 μmol L−1, and had a limit of detection of 1.8 μmol L−1. Remarkably, this sensing platform could evaluate the synergism between SM and five typical lipid-soluble antioxidants: tert-butyl hydroquinone, vitamin E, butyl hydroxyanisole, propyl gallate, and butylated hydroxytoluene. Owing to its low redox potential, SM could reduce antioxidant radicals and promote their regeneration, which increased the overall antioxidant performance. The g-C3N4/CuS/TiO2 PEC sensor exhibited high sensitivity, satisfactory selectivity, and stability, and was successfully applied for SM determination in both soybean and peanut oils. The findings of this study provide guidance for the development of nutritional foods, nutrition analysis, and the treatment of diseases caused by free radicals
Risk factors for acute postoperative hypertension in non-cardiac major surgery: a case control study
Abstract Purpose Acute postoperative hypertension (APH) is a common complication during the anesthesia recovery period that can lead to adverse outcomes, including cardiovascular and cerebrovascular accidents. Identification of risk factors for APH will allow for preoperative optimization and appropriate perioperative management. This study aimed to identify risk factors for APH. Patients and methods In this retrospective single-center study, 1,178 cases were included. Data was entered by two investigators, and consistency analysis was performed by another. Patients were divided into APH and non-APH groups. A predictive model was built by multivariate stepwise logistic regression. The predictive ability of the logistic regression model was tested by drawing the receiver operating characteristic (ROC) curve and calculating the area under the curve (AUC). Hosmer and Lemeshow goodness-of-fit (GOF) test was performed to reflect the goodness of fit of the model. Calibration curve was created to represent the relationship between predicted risk and observed frequency. Sensitivity analysis was performed to evaluate the robustness of the results. Results Multivariate logistic regression analysis showed that age over 65 years (OR = 3.07, 95% CI: 2.14 ~ 4.42, P < 0.001), female patients (OR = 1.37, 95% CI: 1.02 ~ 1.84, P = 0.034), presence of intraoperative hypertension (OR = 2.15, 95% CI: 1.57 ~ 2.95, P < 0.001), and use of propofol in PACU (OR = 2.14, 95% CI: 1.49 ~ 3.06, P < 0.001) were risk factors for APH. Intraoperative use of dexmedetomidine (OR = 0.66, 95% CI: 0.49 ~ 0.89, P = 0.007) was a protective factor. Higher baseline SBP (OR = 0.90, 95% CI: 0.89 ~ 0.92, P < 0.001) also showed some correlation with APH. Conclusions The risk of acute postoperative hypertension increased with age over 65 years, female patients, intraoperative hypertension and restlessness during anesthesia recovery. Intraoperative use of dexmedetomidine was a protective factor for APH
Factors responsible for unanticipated hypertension during emergence from general anesthesia
Design and experimental verification of the working mode of an electrostatic suspension accelerometer
An electrostatic suspension accelerometer is an important instrument for measuring quasi-steady micro-acceleration. A reasonable working mode is the premise to ensure acquisition and stable control of the accelerometer in-orbit and then to carry out high-precision linear measurement. Based on the dynamic model analysis of the electrostatic suspension accelerometer, and taking the force balance of inertial proof mass as the fundamental requirement, the design of the acquisition working mode and measurement working mode based on displacement sensing output and feedback control output is proposed. The rationality and feasibility of the proposed working mode design are verified by the ground drop tower test of the Taiji-1 accelerometer prototype and in-flight test of the actual product
Electrochemically Controlled Atom Transfer Radical Polymerization for Electrochemical Aptasensing of Tumor Biomarkers
Tumor biomarkers are of great value
in the liquid biopsy of malignant
tumors. In this work, a simple and cost-friendly electrochemical aptasensor
was presented for the highly sensitive and selective detection of
glycoprotein tumor biomarkers. The DNA aptamer-modified electrode
was used as the sensing interface to specifically capture the target
glycoprotein tumor biomarkers, to which the alkyl halide initiators
for atom transfer radical polymerization (ATRP) were then attached
via the esterification crosslinking between the boronic acid group
and the cis-dihydroxyl sites of the conjugated oligosaccharide
chains on glycoprotein tumor biomarkers followed by the growth of
long-chain polymers through electrochemically controlled ATRP (eATRP)
to efficiently recruit the ferrocene detection tags. As there are
tens to hundreds of cis-dihydroxyl sites on a glycoprotein
tumor biomarker for attaching ATRP initiators while each long-chain
polymer can recruit hundreds to thousands of ferrocene detection tags,
a significantly high current signal can be generated even in the presence
of ultralow-abundance targets. Hence, the eATRP-based electrochemical
aptasensor is capable of sensitively and selectively detecting glycoprotein
tumor biomarkers. Using alpha-fetoprotein as the model target, the
limit of detection was demonstrated to be 0.32 pg/mL. Moreover, the
aptasensor has been successfully applied to detect glycoprotein tumor
biomarkers in human serum samples. In view of its high sensitivity
and selectivity, simple operation, and cost-friendliness, the eATRP-based
electrochemical aptasensor shows great promise in the glycoprotein-based
liquid biopsy of malignant tumors, even at the early stage of development
ERα up-regulates the transcription of the MGARP promoter and acts in synergy with Sp1 to activate MGARP transcriptional activity.
<p>A. pGL3-(−3 kb) reporter and different doses of ERα expression plasmid were co-transfected into HEK-293T cells to determine the dose-dependent manner of ERα in regulating the MGARP promoter by luciferase assay. B. The functional synergy between Sp1 and ERα was determined by cotransfection of the full-length MGARP promoter (−3 kb) or various promoter truncates with or without Sp1 plasmids for Luc assay as indicated. C. The synergystic transactivation activity of ERα and Sp1 under the stimulation of estrogens. The HEK-293T cells were treated with or without 10 nM of estradiol (E2) for 24 hours post transfection of pGL3-(−3 kb) and ERα. Subsequently, the Luc assay was performed at 72 hours post transfection. D. Knockdown of Sp1 diminishes the activation function of ERα on MGARP promoter. HEK-293T cells were co-transfected with pGL3-(−3 kb) reporter and ERα, together with Sp1-specific RNAi (630-RNAi or 1722-RNAi) or control RNAi, in the absence or presence of exogenous Sp1. *** represents p<0.001 and <sup>#</sup> represents p>0.05 (no significant difference). E. RT-PCR shows that down-regulation of Sp1 with Sp1-specific RNAi (630-RNAi or 1722-RNAi) results in a reduction in endogenous MGARP mRNA expression in HEK-293T cells when stimulated by 10 nM E2. The cells were treated with or without 10 nM E2 for 24 hours post transfection and total RNA was harvested at 72 hours post transfection for semiquantitative RT-PCR analysis.</p