This paper proposes a variable coefficient combined virtual inertia and primary frequency control strategy for doubly fed induction generators (DFIG) in coordination with diesel generator to ...participate in wind/photovoltaic/diesel microgrid frequency regulation. The frequency response characteristic is analyzed under different wind speeds with corresponding inertia control parameters different. A 10% wind power margin is preserved through overspeed control and pitch angle control to offset the decrease of wind output power after temporary extra power surge, and provide a permanent frequency support for microgrids. The influence of droop control gain setting is also illustrated under different wind velocities. By continuously adjusting the control parameters according to wind speed variation, a variable coefficient method is realized. The method can guarantee an efficient implementation of this strategy in time-varying conditions. Finally, this coordinated control strategy is tested in a storage-independent microgrid with solar, wind, and diesel generators.
In a variety of cancers, long non-coding RNAs (lncRNAs) were believed to play important roles. Nevertheless,
possible molecular mechanism related to miR-20b-5p has not yet been explored in ...endometrial cancer. Differential lncRNAs in endometrial cancer were identified based on microarray analysis (GSE23339). In this research, in the first place,
expression was detected to be increased but miR-20b-5p to be decreased in endometrial cancer tissues and cells. Besides,
expression displayed a negative relationship to miR-20b-5p expression in endometrial cancer tissues. According to gain- and loss-of-function experiments of
, like a ceRNA,
elevated
level and
expression so as to stimulate the migration, proliferation and EMT process of endometrial cancer. Additionally, the knockdown of
slowed down tumor growth, promoted apoptosis and upregulated miR-20b-5p expression but lowered the expressions of
, PCNA and
. Furthermore,
was also verified to stimulate the activity of endometrial cancer with
inhibitor BGB324
and
. To sum up,
accelerates the tumor formation of endometrial cancer through the miR-20b-5p/
/
signaling pathway, thereby providing a novel target for diagnosing and treating endometrial cancer.
Herein we report a protocol for visible-light-induced copper-catalyzed decarboxylative coupling reactions between N-heteroarenes and redox-active esters. Various N-hydroxyphthalimide esters reacted ...with isoquinoline, quinoline, pyridine, pyrimidine, quinazoline, phthalazine, phenanthridine, and pyridazine to give the corresponding products in modest to excellent yields. The reactions proceed under mild conditions and have a broad scope and high functional group tolerance. Mechanistic studies revealed that the catalytic behavior of CuI photocatalyst generated in situ was consistent with that of preformed Cu(dmp)(xantphos)BF4.
To investigate the roles of plasma
in the pathogenic process of Type 2 diabetes (T2D) with diabetic retinopathy (DR). T2D patients included patients without DR (NDR) group, patients with ...non-proliferative/background DR (BDR) group and patients with proliferative DR (PDR) group. Healthy individuals served as control group. Fasting plasma glucose (FPG), glycosylated haemoglobin (HbA1c), triacylglycerol (TG), total cholesterol (TC), urine creatinine (Cr), fasting blood glucose (FBG), blood urea nitrogen (BUN), low-density lipoprotein cholesterol (LDL-C), fasting insulin (FINS) and plasma
expression were measured. Quantitative real-time PCR (qRT-PCR) was applied to detect
expression. Pearson analysis was used to conduct correlation analysis and receiver operating characteristic (ROC) curve was used to analyse the diagnostic value of
in T2D with DR. Compared with the control group, FBG and HbA1c increased in the NDR group; compared with the control and NDR groups, disease course, HbA1c, FPG levels and homoeostasis model assessment of insulin resistance (HOMA-IR) were increased in the BDR and PDR groups; and compared with the BDR group, disease course, HbA1c and FPG levels were higher in the PDR group.
expression was higher in the BDR group than the control group, and higher in the PDR group than the BDR group.
expression was positively related with disease course, HbA1C, FPG and HOMA-IR, and had diagnostic value for T2D with DR and PDR. The plasma
expression was increased in the development of T2D with DR and can be used as an indicator for the severity of T2D with DR.
With the increasing share of wind power, it is expected that wind turbines would provide frequency regulation ancillary service. However, the complex wake effect intensifies the difficulty in ...controlling wind turbines and evaluating the frequency regulation potential from the wind farm. We propose a novel frequency control scheme for doubly-fed induction generator (DFIG)-based wind turbines, in which the wake effect is considered. The proposed control scheme is developed by incorporating the virtual inertia control and primary frequency control in a holistic way. To facilitate frequency regulation in time-varying operation status, the control gains are adaptively adjusted according to wind turbine operation status in the proposed controller. Besides, different kinds of power reserve control approaches are explicitly investigated. Finally, extensive case studies are conducted and simulation results verify that the frequency behavior is significantly improved via the proposed control scheme.
•N, P, S doped few-graphene-layers carbon is fabricated via a template approach.•The triple-doped carbon has a wafer-biscuit-like structure to prevent agglomeration.•Wafer-biscuit-like carbon anode ...exhibits improved electrochemical performances.•Sodium storage mechanism of the wafer-biscuit-like carbon anode has been explored.
Carbon-based materials are one of the most attractive anodes for sodium-ion batteries because of their wide availability, facile synthesis, and low cost. However, rational designing carbon-based architecture towards upgrading the electrochemical performance of anodes for sodium storage has been a great challenge. Herein, we prepared N, P, S triple-doped few-graphene-layers carbon with expanded interlayer spacing via a scalable template approach. The few-graphene-layers carbon negatively replicates the structure of the layered template to generate a wafer-biscuit-like architecture, which prevents the restack of carbon nanosheets. The interlayer spacing and heteroatom contents of wafer-biscuit-like carbon architecture can be modulated by varying carbonization temperatures. Consequently, the optimum carbon anode delivers a high reversible capacity of 329 mAh g−1, good rate capability, and long-term stability of 300 cycles at 1 A g−1. Furthermore, the sodium storage mechanism of wafer-biscuit-like carbon anodes has been systematically explored.
Wafer-biscuits-like few-graphene-layers carbon with N, P, S triple-doping and expanded interlayer spacing has been fabricated via a hard template approach using a polymer as the precursor and a layered silicate as the hard template. The unique carbon anode exhibits upgraded electrochemical performances and fast kinetic processes of sodium storage compared to many non-templated carbon anodes. Display omitted
1 The American College of Cardiology (ACC)/American Heart Association (AHA) score is one of the typical and accurate model to evaluate the 10-year risk of a first hard atherosclerotic cardiovascular ...disease (ASCVD) event based on a sex-and-race large Pooled Cohort study. ...the present study aimed to investigate the association between the ACC/AHA risk score and the Gensini Score (GS) system, and determine whether ACC/AHA score could predict the presence and severity of CAD. Figure 1A illustrates the results of ACC/AHA risk scores. ...linear and logistic regressions were applied to identify the causal association of ACC/AHA risk score with the presence and severity of CAD. Just like our present results, several studies have explored some risk scoring systems with the presence and severity of CAD, such as Framingham risk score,5 MESA,6 SCORE,4 and so on. Besides for models from CVD risk prediction, some research groups combine different risk factors to construct a novel statistical model for predicting the presence and severity of CAD.
Background： Pathophysiological processes, such as malignancy, can lead to the formation of stiffer tissue in lung cancers. Endobronchial ultrasound rEBUS） elastography is a novel technique for ...measuring tissue stiffness during EBUS-guided transbronchial needle aspiration （EBUS-TBNA）. The current study was conducted to investigate the diagnostic value of EBUS elastography tbr mediastinal and hilar lymph node metastasis in lung cancers. Methods： From January 2014 to January 2015, 40 patients suspected of lung cancer were enrolled, and a total of 68 lymph nodes were evaluated by EBUS-TBNA. EBUS-guided elastography of lymph nodes was perfornaed prior to EBUS-TBNA. Standard EBUS characteristics were also described. Pathological determination of malignant or benign lymph nodes was used as the gold standard for this study. If EBUS-TBNA did not result in a tbrmal pathological diagnosis of malignancy, patients were referred for a surgical procedure. Comparisons of elastography and standard EBUS characteristics were made between benign and malignant lymph nodes. Results： Elastography grading scores and strain ratios showed significant differences between benign and malignant lymph nodes （P = 0.000）. The elastography strain ratio was more sensitive and specific for determining malignant lymph nodes than elastography grading score or standard EBUS criteria. The receiver operating characteristic curve for the elastography strain ratio showed an area under the curve of 0.933. The best cut-off point of the strain ratio for differentiating malignant from benign lymph nodes was 32.07. The elastography strain ratio had a sensitivity of 88.1%, the specificity of 80.8%, positive predictive value of 88.1%, and negative predictive value of 80.8% for distinguishing malignant from benign nodes. The overall accuracy of elastography strain ratio was 85.3%. The strain ratio of malignant and benign lymph nodes positively correlated with the elastography grading score （r = 0.561, P = 0.000）. Conclusions： EBUS elastography can be effectively used to predict mediastinal and hilar lymph node metastases in lung cancer. This noninvasive technique may thus complement standard EBUS and help guide EBUS-TBNA procedures.
To observe the clinical efficacy of Huazhuo Jiedu formula in treating chronic erosive gastritis (CEG) patients with syndrome of accumulation of turbidity and toxicity, explore its mechanism by ...observing the changes in expression levels of hypoxia inducible factor (HIF-1α), vascular endothelial growth factor (VEGF) in serum and gastric mucosa tissues after treatment, and provide theoretical basis for the clinical application of Huazhuo Jiedu formula in treating chronic erosive gastritis. All 70 patient of CEG were randomly divided into control group and treatment group, 35 cases in each group. The patients in control group received Alatan Wuwei Wan, bid, 1 bag/time; while the patients in treatment group were given with Huazhuo Jiedu formula, 1 dose/day. The course of the treatment was 6 months in both groups. The changes in clinical symptoms, gastroscopic signs, pathology and the expression levels of HIF-1α, VEGF, and phosphatase and tensin homolog deleted on chromosome ten (PTEN) in serum and gastric mucosa t
Due to the critical nature of the ramp-up phase of an efficient steam-assisted gravity drainage (SAGD) process, it is important to understand the physics of the steam chamber ramp-up phase in order ...to improve SAGD production performance. In conventional numerical simulation models, the dynamics of the steam chamber ramp-up phase are not fully resolved because of unclear steam–oil–water interactions during the vertical growth of the steam chamber and how its state changes as the reservoir parameters vary. This work provides an efficient approach for the numerical modeling of the steam chamber ramp-up phase in an SAGD operation. The steam chamber ramp-up phase was fully examined through the consideration of the effects of the temperature-dependent oil–water–gas multiphase flow system and the vertical countercurrent flow. The simulation results revealed that for the large temperature gradient of the mobile oil zone at the edge of the steam chamber, a delicate temperature-dependent multiphase flow system was essential for the reliable estimation of the SAGD ramp-up phase. The vertical countercurrent flows of oil–gas and oil–condensate were the dominant mechanisms over cocurrent flow, which significantly impacted the steam chamber ramp-up rate. The numerical model physically predicted the steam chamber ramp-up phase and could be used to efficiently compute a field-scale simulation using a dynamic gridding function that was based on a fine grid model.
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