24 results on '"Rongbing Chen"'
Search Results
2. Association of uterine fibroids with increased blood pressure: a cross-sectional study and meta-analysis
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Yequn Chen, Nianling Xiong, Jiaxin Xiao, Xiru Huang, Rongbing Chen, Shu Ye, and Xuerui Tan
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Cross-Sectional Studies ,Leiomyoma ,Physiology ,Hypertension ,Uterine Neoplasms ,Internal Medicine ,Humans ,Blood Pressure ,Female ,Cardiology and Cardiovascular Medicine - Abstract
Uterine fibroids (UFs) are the most common benign gynecological tumor and greatly affect reproductive health in women of reproductive age. Some studies have indicated an association between UFs and several cardiovascular disease (CVD) risk factors. To determine whether UFs are associated with increased blood pressure, we performed a cross-sectional study and meta-analysis. In the cross-sectional study, 8401 participants who underwent a physical examination at the First Affiliated Hospital of Shantou University Medical College from June 2011 to June 2013 were divided into a uterine fibroid group (1617 cases) and a control group (6784 cases) to assess the relationship between UFs and blood pressure. Then, we conducted a systematic review to confirm the results. The cross-sectional study showed that UFs were associated with an increased rate of elevated blood pressure [OR = 1.35, 95% confidence interval (CI): 1.016-1.792]. The meta-analysis revealed a significant association between UFs and the prevalence of hypertension [pooled OR = 1.44, 95% CI: 1.17-1.75, P = 0.0004; I
- Published
- 2022
3. Effect of probiotic supplementation on in-hospital mortality in patients with acute myocardial infarction: a study protocol for an open-label, randomized, controlled, superiority clinical trial
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Rongbing Chen, Xuerui Tan, Yequn Chen, Xin Wang, Yan Zhou, Liekai Hong, Nianling Xiong, Jinxiu Zhu, and Shu Ye
- Abstract
Background: Recent studies have demonstrated a correlation between intestinal flora and the severity of myocardial infarction as well as post-myocardial infarction repair. However, few studies have investigated whether probiotics reduce mortality and improve cardiovascular outcomes in patients with acute myocardial infarction. In this study, we will conduct a randomized controlled trial (RCT) to evaluate the effect of probiotics on in-hospital mortality and incidence of major adverse cardiovascular events (MACE) in patients with acute myocardial infarction (AMI). Methods: This is an open-label, randomized, controlled, superiority clinical trial involving 2594 adult patients who diagnosed with acute myocardial infarction. Patients will be randomized to (1)receive bifidobacteria triple viable capsule (Bifidobacterium longum, Lactobacillus acidophilus, and Enterococcus faecalis) 840 mg, twice a day, plus standard treatment strategy during the hospital stay , for a maximum of 30 days, or (2)receive the standard treatment strategy and will not take the bifidobacterium triple live capsule. The primary outcome was in-hospital all-cause mortality. Discussion: The purpose of this clinical trial is to determine whether probiotics can reduce in-hospital mortality and improve prognosis in patients with AMI, and the results will provide evidence for probiotics as a complementary treatment for AMI. Trial registration: Chinese Clinical Trials Registry ChiCTR2000038797. Registered on 2 October 2020.
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- 2022
4. A Literature Review of Resiliency Technologies in Military Software Defined Networks
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Guozhu YAN, Qiongyu Wu, Rongbing Chen, Linfeng Du, and Shuangyin Ren
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- 2022
5. Dysnatremia is associated with increased risk of all-cause mortality within 365 days post-discharge in patients with atrial fibrillation without heart failure: A prospective cohort study
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Yan Zhou, Dong Lin, Shiwan Wu, Jiaxin Xiao, Min Yu, Zhongbo Xiao, Muli Wu, Zhisheng Chen, Cuihong Tian, Rongbing Chen, Yequn Chen, and Xuerui Tan
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Cardiology and Cardiovascular Medicine - Abstract
AimThe aim of this study is to evaluate the association between serum sodium concentrations at hospital admission and all-cause mortality within 365 days post-discharge in patients with atrial fibrillation (AF) without heart failure (HF).MethodsThe prospective cohort study enrolled 1,446 patients with AF without HF between November 2018 and October 2020. A follow-up was performed 30, 90, 180, and 365 days after enrollment through outpatient visits or telephone interviews. All-cause mortality was estimated in three groups according to serum sodium concentrations: hyponatremia (< 135 mmol/L), normonatremia (135–145 mmol/L), and hypernatremia (> 145 mmol/L). We estimated the risk of all-cause mortalities using univariable and multivariable Cox proportional hazards models with normonatremia as the reference.ResultsThe all-cause mortalities of hyponatremia, normonatremia, and hypernatremia were 20.6, 9.4, and 33.3% within 365 days post-discharge, respectively. In the univariable analysis, hyponatremia (HR: 2.19, CI 1.5–3.2) and hypernatremia (HR: 4.03, CI 2.32–7.02) increased the risk of all-cause mortality. The HRs for hyponatremia and hypernatremia were 1.55 (CI 1.05–2.28) and 2.55 (CI 1.45–4.46) after adjustment for age, diabetes mellitus, loop diuretics, antisterone, antiplatelet drugs, and anticoagulants in the patients with AF without HF. The association between serum sodium concentrations and the HRs of all-cause mortality was U-shaped.ConclusionDysnatremia at hospital admission was an independent factor for all-cause mortality in patients with AF without HF within 365 days post-discharge.
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- 2022
6. Simulating Drillstring Dynamics Motion and Post-Buckling State with Advanced Transient Dynamics Model
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Zhengxin Zhang, Sheldon Andre Rawlins, Rongbing Chen, Yuelin Shen, and Wei Chen
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Mechanical Engineering ,Dynamics (mechanics) ,Energy Engineering and Power Technology ,Motion (geometry) ,02 engineering and technology ,Mechanics ,010502 geochemistry & geophysics ,01 natural sciences ,020401 chemical engineering ,Buckling ,State (computer science) ,Transient (oscillation) ,0204 chemical engineering ,Geology ,0105 earth and related environmental sciences - Abstract
SummaryAs drilling sections become deeper and longer, transferring more weight downhole to improve rate of penetration is the primary concern for the operator. Drillstring dynamics and buckling are some primary limiters for drilling efficiency. Aggressive drilling parameters may lead to severe downhole dynamics, which leads to cutter breakage and tool damage. When axial compression exceeds a certain threshold, the drillstring buckles sinusoidally inside the wellbore first, followed by helical buckling. Buckling leads to accelerated joint wear, tool fatigue failures, and lower drilling efficiency. To better manage drillstring dynamics and buckling, we propose a method of simulating drillstring dynamics motion and postbuckling state using an advanced transient dynamics model.An analysis methodology was developed on the basis of the finite element transient dynamics model. The model captures the enriched physics of drillstring dynamics and loading: the large deformation of buckled drillstring, the strong nonlinearity of contact and friction forces, and the dynamically triggered instability caused by drilling rotation. Transient dynamics simulations are conducted for drillstring with the actual well trajectory and rotation speed. The weight on bit (WOB) is ramped up gradually, and the drillstring deformation is monitored to detect the onset of buckling or dynamics instability.To conduct the model validation, the buckling inception loads predicted by the model are compared against the analytical equation of critical buckling loads. A field extended reach drilling (ERD) job was simulated by the model. The downhole weight and torque data from the measurement-while-drilling (MWD) tool was used to validate the weight transfer prediction by the model. Most existing buckling theories use the analytical equations of critical buckling load, which were normally derived on the basis of the idealized assumptions, such as perfect wellbore shape and uniform tubular geometry. The proposed method simulates the drillstring behaviors in the field drilling conditions and aims to capture effects of wellbore friction and string rotation. The transient dynamics model is capable of simulating drillstring dynamics movement (whirling and snaking) and weight lockup under severe helical buckling. An automatic method is proposed to interpret the drillstring behaviors from the simulation results. Using the transient dynamics model, the procedure presented in this article can simulate the dynamics and buckling behaviors of drillstring and help mitigate associated risks in well-planning and execution phases.
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- 2021
7. A UAV UGV Collaboration Paradigm Based on Situation Awareness: Framework and Simulation
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Shuangyin Ren, Rongbing Chen, and Wei Gao
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- 2022
8. Dysnatremia Predicts All-Cause Mortality in Atrial Fibrillation Patients Without Heart Failure: A Prospective Cohort Study
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Xuerui Tan, Yequn Chen, Yan zhou, Dong Lin, Shiwan Wu, Jiaxin Xiao, Min Yu, Zhongbo Xiao, Muli Wu, Zhisheng Chen, Cuihong Tian, and Rongbing Chen
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
9. Prophenoloxidase-positive tubes derived from the hindguts may be the doorkeeper to detoxify the waste metabolites collected by Malpighian tubules in Lepidoptera insects
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Yingyu Tang, Ying Zhang, Qiaoli Zhang, Rongbing Chen, Liyuan Gong, Xuefei Wei, Jingfeng Yang, Kai Wu, Wuren Huang, Shirong Li, Shahzad Toufeeq, Qiuning Liu, and Erjun Ling
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Lepidoptera ,Enzyme Precursors ,Immunology ,Animals ,Malpighian Tubules ,Catechol Oxidase ,Developmental Biology - Abstract
Prophenoloxidase (PPO), an important immunity protein in insects, is mainly produced by hemocytes and released into the hemolymph upon cell lysis. In addition, PPO can also be produced by epidermal cells in the foregut to detoxify the toxic plant secondary metabolites and in the hindgut to kill pathogens through PPO-induced melanization. Previously, we noticed a pair of tubes extended from the larval hindgut became melanized upon staining in dopamine dissolved in 30% ethanol. However, the structure and function of these tubes are largely unknown. In this study, we performed staining of the tubes and the neighboring Malpighian tubule for further confirmation. Eventually, we detected PPO inside epidermal cells of the tubes, and called them as PPO-positive tubes. We observed that the PPO-positive tubes are physically derived from the hindgut but strongly adhere to the Malpighian tubule. Inside the PPO-positive tubes, there is an acellular peritrophic membrane to protect the epidermal cells. Furthermore, the PPO-positive tubes act like a doorkeeper to firstly detoxify the metabolite wastes collected by the Malpighian tubule from the hemolymph.
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- 2021
10. Involvement of Epidermis Cell Proliferation in Defense Against
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Wuren, Huang, Ruijuan, Tang, Shirong, Li, Ying, Zhang, Rongbing, Chen, Liyuan, Gong, Xuefei, Wei, Yingyu, Tang, Qiuning, Liu, Lei, Geng, Guoqing, Pan, Brenda T, Beerntsen, and Erjun, Ling
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Host Microbial Interactions ,Virulence ,fungi ,Chitinases ,Immunology ,Hyphae ,Chitin ,Lipase ,Spores, Fungal ,Bombyx ,infection ,Mycoses ,Microscopy, Electron, Transmission ,epidermis ,Mutation ,Insect Proteins ,Animals ,insect ,cuticle ,Pest Control ,Beauveria ,Beauveria bassiana ,Peptide Hydrolases ,Cell Proliferation ,Original Research - Abstract
Entomopathogenic fungi Beauveria bassiana can infect many species of insects and is used as a biological pesticide world-wide. Before reaching the hemocoel, B. bassiana has to penetrate the integument which is composed of a thick chitin layer and epidermal cells. Some chitinase, protease and lipase secreted by B. bassiana are probably involved in the fungal penetration of the integument. While microscopic proof is needed, it is difficult to locate the precise infection sites following the traditional method of immersion infection. Consequently, we developed a new method to inoculate conidia solution into a single fixed-site on the back of one segment. This fixed-site infection method is pathogenic but it is also dose dependent. Using the fixed-site infection protocol, it is also very convenient to track hyphae inside the cuticle layer by light and transmission electron microscopy. The fact that few hyphae were detected inside the chitin layer after fixed-site infection with mutant ΔBPS8, a protease secreted during fungi germination, indicates that this method is suitable for screening genes involved in penetrating the integument in large scale. We also found that melanization occurs before new hyphae penetrate the chitin layer. Most importantly, we discovered that fungal infection can induce epidermal cell proliferation through DNA duplication and cell division, which is essential for the host to defend against fungal infection. Taken together the fixed-site infection method may be helpful to determine the mechanism of fungal and host interaction in the integument so as to effectively exert fungal biological virulence.
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- 2021
11. Identification of Phospho-Tyrosine Targets as a Strategy for the Treatment of Esophageal Adenocarcinoma Cells
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Sumeet K. Mittal, Thalachallour Mohanakumar, Timothy Fleming Ph.D., John Lee, R. Bremner, and Rongbing Chen
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0301 basic medicine ,Afatinib ,Receptor tyrosine kinase ,OncoTargets and Therapy ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,medicine ,kinase inhibitors ,Pharmacology (medical) ,ERBB3 ,esophageal cancer ,Tyrosine ,Receptor ,Original Research ,treatment ,biology ,Chemistry ,tyrosine phosphorylation ,Tyrosine phosphorylation ,030104 developmental biology ,Oncology ,030220 oncology & carcinogenesis ,biology.protein ,Cancer research ,Erlotinib ,Tyrosine kinase ,tyrosine kinase receptors ,medicine.drug - Abstract
John Lee, Rongbing Chen, T Mohanakumar, Ross Bremner, Sumeet Mittal, Timothy P Fleming Norton Thoracic Institute, St. Joseph Hospital, Phoenix, AZ, USACorrespondence: Timothy P FlemingSt. Joseph’s Hospital and Medical Center, Norton Thoracic Institute, 124 W. Thomas Road, Suite 105, Phoenix, AZ, 85013, USATel +1 314-960-2331Email Timothy.Fleming@commonspirit.orgIntroduction: Esophageal cancer (EC) is an aggressive cancer type that is increasing at a high rate in the US and worldwide. Extensive sequencing of EC specimens has shown that there are no consistent driver mutations that can impact treatment strategies. The goal of this study was to identify activated tyrosine kinase receptors (TKRs) in EC samples as potential targets in the treatment of EC.Methods: Activated tyrosine kinase receptors were detected using a dot-blot array for human TK receptors. Human esophageal cancer cell lines were transplanted into immunocompromised mice, and tumor xenografts were subjected to tyrosine kinase inhibitors based on the dot-blot array data.Results: Using the OE33 esophageal cancer cell line, we identified activated EGF receptor (EGFR), as well as ErbB2 and ErbB3. Treatment of this cell line with erlotinib, a specific inhibitor of EGFR, did not impact the growth of this tumor cell line. Treating the OE33 cell line with afatinib, a pan-EGFR family inhibitor resulted in the growth inhibition of OE33, indicating that the ErbB2 and ErbB3 receptors were contributing to tumor cell proliferation. Afatinib treatment of mice growing OE33 tumors inhibited growth of the OE33 tumor cells.Discussion: Activated tyrosine kinase receptors were readily detected in both cancer cell lines and human esophageal cancer samples. By identifying the activated receptors and then using the appropriate tyrosine kinase inhibitors, we can block tumor growth in vitro and in animal xenografts. We propose that identifying and targeting activated TKRs can be used as a personalized EC tumor treatment strategy.Keywords: tyrosine phosphorylation, tyrosine kinase receptors, esophageal cancer, treatment, kinase inhibitors
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- 2021
12. The complete chloroplast genome sequence of
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Li Li, Shengcai Luo, Rongbing Chen, Linhui Wu, and Yunfei Hu
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0106 biological sciences ,0301 basic medicine ,Whole genome sequencing ,phylogenetic analysis ,Biology ,010603 evolutionary biology ,01 natural sciences ,Genome ,Camellia sinensis ,Chloroplast ,03 medical and health sciences ,030104 developmental biology ,Synonym (taxonomy) ,Botany ,Genetics ,Chloroplast genome ,Molecular Biology ,Illumina dye sequencing ,Mitogenome Announcement ,Research Article - Abstract
Here, combining PacBio and Illumina sequencing data, we reported the complete chloroplast genome of the first Wuyi tea (Bohea), Camellia sinensis cv. Dahongpao (DHP) with very high economic value. The chloroplast genome was 157,077 bp in length, with a large single copy (LSC) region of 86,633 bp, a small single-copy (SSC) region of 18,282 bp, separated by two inverted repeat (IR) regions of 26,081 bp each. It contained a total of 137 genes, with an overall GC content of 37.29%. The phylogenetic analysis showed that DHP was sister to C. sinensis cv. Longjing.
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- 2021
13. Simulating Drillstring Postbuckling State and Weight Transfer with Advanced Transient Dynamics Model
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Yuelin Shen, Wei Chen, Zhengxin Zhang, Rongbing Chen, and Sheldon Andre Rawlins
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020401 chemical engineering ,Dynamics (mechanics) ,Weight transfer ,02 engineering and technology ,Mechanics ,State (computer science) ,Transient (oscillation) ,0204 chemical engineering ,010502 geochemistry & geophysics ,01 natural sciences ,Geology ,0105 earth and related environmental sciences - Abstract
As the drilling sections become deeper and longer, transferring more weight downhole to improve ROP is the primary concern to the operator. Drillstring buckling is a primary concern when using very aggressive drilling parameters. Buckling is a phenomenon where the drillstring suddenly loses stability as axial compression exceeds a certain threshold. The drillstring first buckles sinusoidally inside the wellbore which is then followed by helical buckling. Buckling leads to accelerated joint wear, tool fatigue failures, and lower drilling efficiency. To better manage the buckling risk, this paper proposes a method of simulating drillstring buckling inception and post-buckling state using an advanced transient dynamics model. A buckling and post-buckling analysis methodology was developed based on the finite element transient dynamics model. The model captures the enriched physics involved in the buckling phenomenon: the large deformation of buckled drillstring, the strong non-linearity of contact and friction forces, and the dynamically triggered buckling due to drilling rotation. Transient dynamics simulations are conducted for drillstring with the actual well trajectory and rotation speed. Weight on bit (WOB) is ramped up gradually, and the drillstring deformation is monitored to detect the onset of buckling. The post-buckling state is examined to evaluate drilling efficiency and string reliability. To conduct the model validation, an extended reach drilling (ERD) job was analyzed by the model. A measurement while drilling (MWD) tool was deployed in BHA to measure the downhole weight and torque. The simulation implies the helical buckling occurs in drill-pipe and captures the drilling weight and torque loss due to buckled string. Most existing buckling theories use the analytical equations of critical buckling load, which were normally derived based on the idealized assumptions, such as perfect wellbore shape and uniform tubular geometry, but neglect friction and string rotation. The proposed method simulates the drillstring buckling in the actual field drilling conditions. It gives more realistic predictions of buckling inception load and post-buckling configuration. The transient dynamics model is capable of simulating drillstring whirl and weight lockup under the severe helical buckling. Based on the simulated the post buckling configuration of the string, an automatic interpretation method was proposed to detect the buckling mode and location along the drillstring. Using the transient dynamics model, the simulation procedure presented in this paper can significantly improve drillstring buckling and post-buckling predictions and help mitigate buckling risk in well planning and execution phases.
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- 2020
14. Temporal variation analysis and risk assessment of neonicotinoid residues from tea in China
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Lifeng Li, Jun Ren, Jingguang Li, Shaohua Li, Yongning Wu, Dawei Chen, Rongbing Chen, and Yunfeng Zhao
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China ,Insecticides ,010504 meteorology & atmospheric sciences ,Health, Toxicology and Mutagenesis ,010501 environmental sciences ,Biology ,Toxicology ,Risk Assessment ,01 natural sciences ,Acetamiprid ,Neonicotinoids ,chemistry.chemical_compound ,Chinese tea ,0105 earth and related environmental sciences ,Nitenpyram ,Residue (complex analysis) ,Tea ,Neonicotinoid ,Clothianidin ,General Medicine ,Nitro Compounds ,Thiacloprid ,Pollution ,chemistry ,Thiamethoxam - Abstract
The extensive use of neonicotinoids (NEOs) has caused the release of wide-ranging of residues to the environment and food, and their potential health risks are now receiving more attention. In this study, three surveys were conducted to obtain the overall profiles of NEO residue levels (seven NEOs and one metabolite) in Chinese tea over a period of seven years. A total of 726 tea samples were tested, and nearly 87% of the samples were found to have detectable NEO residues. The overall average detection frequency of acetamiprid was the highest, reaching 73%. Imidacloprid residues in 4.6% of the samples exceeded the Chinese maximum residue limits, whereas clothianidin and nitenpyram had been detected in Chinese tea samples since 2014. The applications of thiacloprid and thiamethoxam gradually increased, and some tea samples with high residue levels appeared in China. These findings signal the replacement of new and old varieties of NEOs in China. Both long- and short-term cumulative exposures to NEOs were calculated based on optimistic and pessimistic models recommended in the EFSA guidelines. In the three survey periods, the average total imidacloprid-equivalent concentrations were 484.63, 1713.36, and 1148.34 μg/kg, respectively. Combined with the refined point estimates and probabilistic models used in this study, the hazard quotients of NEO residues in tea for Chinese tea consumers were found to be low and within the bounds of safety.
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- 2020
15. Development of and Validating a Procedure for Drillstring Fatigue Analysis
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Geng Yun, Yuelin Shen, Rongbing Chen, Wei Chen, and Yani Dong
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020401 chemical engineering ,Stress cycle ,business.industry ,Computer science ,021105 building & construction ,0211 other engineering and technologies ,02 engineering and technology ,Structural engineering ,0204 chemical engineering ,business - Published
- 2018
16. Development of two novel benzoylphenylurea sulfur analogues and evidence that the microtubule-associated protein tau is predictive of their activity in pancreatic cancer
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X. Zhang, Preeti Shah, Gurulingappa Hallur, Ernest Hamel, Antonio Jimeno, Manuel Hidalgo, Rongbing Chen, George Cusatis, Fonda Chan, Elizabeth Garrett-Mayer, Saeed R. Khan, and Audrey Chan
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Cancer Research ,Benzoylphenylurea ,Tau protein ,Mice, Nude ,Antineoplastic Agents ,tau Proteins ,Docetaxel ,Microtubules ,Mice ,Tubulin ,In vivo ,Cell Line, Tumor ,Pancreatic cancer ,medicine ,Animals ,biology ,Chemistry ,Phenylurea Compounds ,Cancer ,medicine.disease ,In vitro ,Gene Expression Regulation, Neoplastic ,Pancreatic Neoplasms ,Oncology ,Biochemistry ,Mechanism of action ,biology.protein ,Cancer research ,Female ,Taxoids ,medicine.symptom ,Neoplasm Transplantation ,Sulfur ,medicine.drug - Abstract
In this work, we evaluated two lead compounds, referred to as SG410 and SG430, obtained from a screen of sulfur benzoylphenylurea analogues, against in vitro and in vivo models of pancreas cancer. Both drugs showed a similar mechanism of action profile, with SG410 being more potent as an inhibitor of tubulin assembly. We determined the best in vivo administration schedule and tested SG410 and SG430 in nine cases of a novel platform of direct pancreas cancer xenografts. Both compounds had antiproliferative activity in vitro in the low nanomolar range, but only SG410 showed significant activity in vivo. Administration of SG410 resulted in significant tumor growth delay in five of nine groups tested. In a direct comparison in three of the cases, SG410 was at least as efficacious as docetaxel. We also sought markers that would be predictive of the efficacy of these agents, and we found such a marker in microtubule-associated protein tau (MAPT). This protein enhances the assembly and stability of microtubules. In both the cell lines and the direct human xenografts, MAPT mRNA and protein levels correlated well. There was also a statistically significant inverse correlation between MAPT expression and sensitivity to the tested agents. In summary, the novel sulfur benzoylphenylurea SG410 showed activity inversely related to MAPT expression in a preclinical model of pancreatic cancer comparable with that observed with docetaxel, another microtubule-targeting agent. [Mol Cancer Ther 2007;6(5):1509–16]
- Published
- 2007
17. Defining Design and Optimization Method: Dynamic Simulation Model Produces Integrated BHA Solutions for Efficient Wellbore Delivery
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Wei Chen, Richard Harmer, Sheldon Andre Rawlins, Rongbing Chen, Yani Dong, and Yuelin Shen
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Wellbore ,Engineering ,business.industry ,Dynamic simulation model ,Control engineering ,business - Abstract
In difficult drilling environments, a critical aspect for success is BHA design optimization in the pre-job phase. In previous operations, modeling and run simulations have proven valuable at helping operators improve drilling efficiency (reduce NPT; increase footage/day), produce high-quality log data and properly position the wellbore to increase contact with the reservoir. To further improve modeling accuracy/reliability, a dynamic modeling system was used for BHA analysis. The FEA (finite element analysis)-based system enables engineers to leverage the team's combined expertise and full suite of drilling tools to optimize a BHA for a specific application. Four criteria are used to evaluate BHA performance during simulations: stability; robustness/reliability; measurement quality; steerability. Simulations are run to determine each configuration's potential for axial, lateral/torsional vibration and identify the root cause and dominant mode. To ensure maximum BHA robustness, the loading on BHA components is mapped/rated allowing refinements to increase BHA service life and reduce the potential for costly NPT. Simulations are run to observe the potential for MWD/LWD tool deformation and sag angle to determine the adverse effect sensor motion could have on measurement quality. To mitigate steerability issues, build/walk tendencies are simulated to determine how the BHA will respond to steering command from RSS/PDM. A wide-range of factors can be considered in this procedure. Various cutting structures and steering tools are analyzed and modified as required. The type and location of BHA components are also modeled and re-positioned for optimization purposes. Various drilling scenarios and operating parameters are fed into the system including RPM/WOB, sliding/rotating time, back-reaming and rotating off bottom. Formation characteristics including rock types, friction factor, heterogeneity/homogeneity, degree/amount of interbedding can all be varied to investigate the BHA's corresponding directional implications and vibrational response. All potential BHA designs are evaluated under a set of pre-defined drilling scenarios. A comparative analysis is performed to investigate BHA responses against each specific criterion to identify the optimum BHA configuration. Operating conditions are analyzed for each BHA and an optimal parameter window of minimized BHA shock and vibration is generated with a range of RPM/WOB recommendations. The authors will present several conclusive case studies that document the method's effectiveness and cost reducing capabilities.
- Published
- 2015
18. Individual RFI classification based on chaotic characteristics
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Li-Chang Qian, Rongbing Chen, Wenfeng Sun, Yingning Peng, and JiaXu
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Engineering ,business.industry ,Radar signal processing ,Speech recognition ,Feature extraction ,Transmitter ,Chaotic ,Entropy (information theory) ,Pattern recognition ,Artificial intelligence ,business ,Transient analysis ,Hilbert–Huang transform - Abstract
This paper provides an efficient approach to classify individual radio-frequency interference in high-frequency radars. By employing empirical mode decomposition as signal pre-process method, stable chaotic characteristics of individual radio-frequency interference are extracted. Based on these stable characteristics and treelike assembly classifier, individual radio-frequency interference can be effectively classified. Detailed real data experiments are finally provided to demonstrate the effectiveness of the proposed method.
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- 2011
19. Characterization of a novel PMA-inducible pathway of interleukin-13 gene expression in T cells
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Giovanni Florio, Marsha Wills-Karp, Jessica Roman, Rongbing Chen, Antonella Cianferoni, Vincenzo Casolaro, Judith C. Keen, Steve N. Georas, and Jia Guo
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Transcription, Genetic ,T-Lymphocytes ,Immunology ,Molecular Sequence Data ,Biology ,Cell Line ,Mice ,Species Specificity ,Interleukin 26 ,Gene expression ,Immunology and Allergy ,Cytotoxic T cell ,Animals ,Humans ,IL-2 receptor ,Promoter Regions, Genetic ,Cells, Cultured ,Protein Kinase C ,Interleukin 3 ,Interleukin-13 ,Base Sequence ,Reverse Transcriptase Polymerase Chain Reaction ,Promoter ,Original Articles ,Molecular biology ,Gene Expression Regulation ,Interleukin 13 ,Interleukin 12 ,Tetradecanoylphorbol Acetate ,Signal Transduction - Abstract
Although interleukin 13 (IL-13) is an important mediator of asthma and allergic diseases, the molecular mechanisms regulating IL-13 gene expression are not well understood. This study was designed to define the molecular mechanisms governing IL-13 gene expression in T cells. IL-13 expression was examined in human peripheral blood T cells and in the EL-4 T-cell line by enzyme-linked immunosorbent assay and reverse-transcription polymerase chain reaction. An IL-13 promoter deletion analysis was performed using luciferase-based reporter plasmids transiently transfected into EL-4 cells by electroporation. DNA binding factors were investigated using electrophoretic mobility shift assays. In contrast to IL-4 expression, which required concomitant activation of calcium- and protein kinase C- (PKC-) dependent signalling pathways, PKC activation alone was sufficient for IL-13 protein secretion in mitogen-primed (but not resting) peripheral blood T cells, and for IL-13 mRNA expression and promoter activity in EL-4 T cells. Promoter deletion analysis localized a phorbol 12-myristate 13-acetate (PMA) -sensitive element to a proximal promoter region between −109 and −79 base pairs upstream from the IL-13 transcription start site. This promoter region supported the binding of both constitutive and PMA-inducible nuclear factors in gel shift assays.
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- 2006
20. Lysophosphatidic acid enhances interleukin-13 gene expression and promoter activity in T cells
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Nitat Sookrung, Viswanathan Natarajan, Rongbing Chen, Joshua M.F. Rubenfeld, Jia Guo, Vincenzo Casolaro, Wanpen Chaicumpa, Steve N. Georas, and Yutong Zhao
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Pulmonary and Respiratory Medicine ,CD4-Positive T-Lymphocytes ,Transcription, Genetic ,Physiology ,T-Lymphocytes ,Gene Expression ,Inflammation ,Biology ,Jurkat cells ,chemistry.chemical_compound ,Jurkat Cells ,Transcription (biology) ,Physiology (medical) ,Gene expression ,Lysophosphatidic acid ,medicine ,Transcriptional regulation ,Humans ,Protein Isoforms ,Promoter Regions, Genetic ,Transcription factor ,Calcimycin ,Interleukin-13 ,Ionophores ,Cell Biology ,Molecular biology ,chemistry ,Interleukin 13 ,lipids (amino acids, peptides, and proteins) ,biological phenomena, cell phenomena, and immunity ,medicine.symptom ,Lysophospholipids - Abstract
Lysophosphatidic acid (LPA) is a membrane-derived lysophospholipid with wide-ranging effects on multiple lung cells including airway epithelial and smooth muscle cells. LPA can augment migration and cytokine synthesis in lymphocytes, but its potential effects on Th2 cytokines have not been well studied. We examined the effects of physiological concentrations of LPA on IL-13 gene expression in human T cells. The Jurkat T cell line and human peripheral blood CD4+ T cells were incubated with LPA alone or with 1) pharmacological agonists of different signaling pathways, or 2) antibodies directed against the T cell receptor complex and costimulatory molecules. Luciferase-based reporter constructs driven by different lengths of the human IL-13 promoter were transfected by electroporation in Jurkat cells treated with and without LPA. The effects of LPA on IL-13 mRNA stability were examined using actinomycin D to halt ongoing transcription. Expression of mRNA encoding LPA2and LPP-1 increased with T cell activation. LPA augmented IL-13 secretion under conditions of submaximal T cell activation. This was observed using pharmacological agonists activating intracellular calcium-, PKC-, and cAMP-dependent signaling pathways, as well as antibodies directed against CD3 and CD28. LPA only slightly prolonged IL-13 mRNA half-life in submaximally stimulated Jurkat cells. In contrast, LPA significantly enhanced transcriptional activation of the IL-13 promoter via regulatory elements contained within proximal 312 bp. The effects of LPA on IL-13 promoter activation appeared to be distinct from those mediated by GATA-3. LPA can augment IL-13 gene expression in T cells, especially under conditions of submaximal activation.
- Published
- 2005
21. Glucocorticoids Inhibit Calcium- and Calcineurin-Dependent Activation of the Human IL-4 Promoter
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Vincenzo Casolaro, Lisa A. Beck, John E. Cumberland, Thomas F. Burke, Mary Brummet, Rongbing Chen, and Steve N. Georas
- Subjects
Immunology ,Calcineurin Inhibitors ,chemistry.chemical_element ,Calcium ,Biology ,Lymphocyte Activation ,Response Elements ,Transfection ,Jurkat cells ,Dexamethasone ,Transactivation ,Jurkat Cells ,Gene expression ,Immunology and Allergy ,Humans ,Promoter Regions, Genetic ,Transcription factor ,Protein Kinase C ,Cell Nucleus ,Base Composition ,NFATC Transcription Factors ,Calcineurin ,Nuclear Proteins ,Molecular biology ,DNA-Binding Proteins ,Enzyme Activation ,chemistry ,Interleukin-4 ,hormones, hormone substitutes, and hormone antagonists ,Immunosuppressive Agents ,Transcription Factors - Abstract
The mechanism by which glucocorticoids (GC) inhibit IL-4 gene expression is currently unknown. In T lymphocytes, IL-4 gene expression is regulated at the level of transcription by increases in intracellular calcium concentration and by the calcium-activated phosphatase calcineurin. In this paper we report that dexamethasone (Dex) inhibits calcium ionophore-induced activation of the human IL-4 promoter in transiently transfected Jurkat T cells. Inhibition of the promoter by Dex is dependent on expression of the GC receptor (GR), because it does not occur in GR-deficient cells. Dex also represses activation of the promoter induced by cotransfecting cells with a constitutively active mutant of calcineurin. Using a series of deletion constructs, we show that the proximal 95 bp of the IL-4 promoter contain a Dex-sensitive regulatory element. This region contains the P1 sequence, a proximal binding site for NF-AT. A calcium-induced but Dex-inhibited nuclear complex containing NF-AT binds to the P1 element in EMSA. Using immunoprecipitation under nondenaturing conditions, we found that the GRα isoform coprecipitates with NF-ATc in nuclear extracts of calcium ionophore- and Dex-treated cells. Taken together, our results show that GC inhibit IL-4 gene expression by interfering with NF-AT-dependent transactivation of the proximal human IL-4 promoter.
- Published
- 2000
22. Stat6 inhibits human interleukin-4 promoter activity in T cells
- Author
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John E. Cumberland, Thomas F. Burke, Ulrike Schindler, Steve N. Georas, Vincenzo Casolaro, and Rongbing Chen
- Subjects
Chloramphenicol O-Acetyltransferase ,Transcription, Genetic ,T-Lymphocytes ,Immunology ,Response element ,Biology ,Transfection ,Biochemistry ,Jurkat Cells ,Epigenetics of physical exercise ,Genes, Reporter ,Tumor Cells, Cultured ,Humans ,Promoter Regions, Genetic ,STAT4 ,Transcription factor ,STAT6 ,Binding Sites ,NFATC Transcription Factors ,Nuclear Proteins ,NFAT ,Promoter ,Cell Biology ,Hematology ,Molecular biology ,Receptors, Interleukin-4 ,DNA-Binding Proteins ,Gene Expression Regulation ,Trans-Activators ,Interleukin-4 ,STAT6 Transcription Factor ,Signal Transduction ,Transcription Factors - Abstract
The differentiation of naive T-helper (Th) cells into cytokine-secreting effector Th cells requires exposure to multiple signals, including exogenous cytokines. Interleukin-4 (IL-4) plays a major role in this process by promoting the differentiation of IL-4–secreting Th2 cells. In Th2 cells, IL-4 gene expression is tightly controlled at the level of transcription by the coordinated binding of multiple transcription factors to regulatory elements in the proximal promoter region. Nuclear factor of activated T cell (NFAT) family members play a critical role in regulating IL-4 transcription and interact with up to five sequences (termed P0 through P4) in the IL-4 promoter. The molecular mechanisms by which IL-4 induces expression of the IL-4 gene are not known, although the IL-4–activated transcription factor signal transducer and activator of transcription 6 (Stat6) is required for this effect. We report here that Stat6 interacts with three binding sites in the human IL-4 promoter by electrophoretic mobility shift assays. These sites overlap the P1, P2, and P4 NFAT elements. To investigate the role of Stat6 in regulating IL-4 transcription, we used Stat6-deficient Jurkat T cells with different intact IL-4 promoter constructs in cotransfection assays. We show that, whereas a multimerized response element from the germline IgE promoter was highly induced by IL-4 in Stat6-expressing Jurkat cells, the intact human IL-4 promoter was repressed under similar conditions. We conclude that the function of Stat6 is highly dependent on promoter context and that this factor promotes IL-4 gene expression in an indirect manner.
- Published
- 1998
23. The molecular basis of IL-4 dysregulation in the atopic condition
- Author
-
Steve N. Georas, John E. Cumberland, Thomas F. Burke, Vincenzo Casolaro, and Rongbing Chen
- Subjects
Transcriptional regulation ,Coding region ,Heterologous ,Promoter ,Luciferase ,Biology ,Enhancer ,Gene ,Molecular biology ,Interleukin 4 - Abstract
Publisher Summary The knowledge of IL-4 transcriptional regulation comes from studies of a relatively restricted region (approximately 300 bp) within the 12,500 bp intergene segment located between the IL-13 and IL-4 gene coding regions. This IL-4 proximal upstream region is indeed sufficient to confer Th2 cell specificity on heterologous gene transcription. A recent report on IL-4-1uciferase and TCR-αβ double transgenic mice demonstrates that an extended 800 bp IL-4 upstream region is preferentially activated in Th2 cells, while a lower degree of Th2 cell specificity was attained in transgenics for reporter constructs driven by an artificial promoter made of three copies of the P1/OAP40 region placed upstream of the IL-4 minimal promoter (up to bp -58). However, luciferase mRNA expression in Th2 cells was very low when compared with expression of the native IL-4 gene, implicating a role for an as yet unidentified enhancer region outside the IL-4 promoter region. Possible IL-4 enhancers might reside somewhere in the IL-13/IL-4 intergene region, downstream of the IL-4 gene, or, in an untranslated area within the coding region of the IL-4 gene.
- Published
- 1998
24. Polymorphic nucleotides within the human IL-4 promoter that mediate overexpression of the gene
- Author
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Zhimin, Song, Casolaro, Vincenzo, Rongbing, Chen, Georas, Steve N., Dimitris, Monos, and Santa Jeremy Ono
- Subjects
Hypersensitivity, Immediate ,B-Lymphocytes ,Base Sequence ,Transcription, Genetic ,Molecular Sequence Data ,Immunoglobulin E ,Transcription Factor AP-1 ,Th2 Cells ,Gene Expression Regulation ,Leukemia, Basophilic, Acute ,Sequence Homology, Nucleic Acid ,Mutagenesis, Site-Directed ,Tumor Cells, Cultured ,Humans ,Leukemia-Lymphoma, Adult T-Cell ,Genetic Predisposition to Disease ,Disease Susceptibility ,Interleukin-4 ,Promoter Regions, Genetic ,Sequence Alignment ,Alleles ,Cell Line, Transformed - Abstract
Atopy, which predisposes individuals to develop asthma, severe systemic anaphylaxis, and atopic dermatitis, is usually associated with dramatically elevated total serum IgE levels and is thought to be controlled by a major susceptibility gene and multiple minor susceptibility genes. A recent sib-pair analysis revealed a tight linkage between markers on 5q31.1 and a major susceptibility gene controlling total serum IgE levels. Due to its location within this cluster and its biologic role in Ig class switching and Th2 cell differentiation, the IL-4 gene has emerged as one major candidate for the atopy gene. In one model, polymorphisms within IL-4 regulatory elements might result in overexpression of the gene, amplifying Th2 cell differentiation and class switching to IgE. In support of this model, we report that the human IL-4 promoter exists in multiple allelic forms that exhibit distinct transcriptional activities in IL-4-positive T cells. A particular allele has an unusually high transcriptional activity. A nucleotide substitution within a recently described OAP40 element located just upstream of an NF-AT site (P sequence) appears to be largely responsible for the increased promotor strength of this particular allelic form of the IL-4 promoter. In EMSAs, this substitution results in a markedly enhanced affinity for sequence-specific complexes exhibiting an AP-1 specificity. The identification of allelic nucleotides, which results in overexpression of the IL-4 gene, provides specific targets for a comprehensive screening of atopic and nonatopic individuals and may provide a clue for genetic predisposition for atopy.
- Published
- 1996
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