Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular se...Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular sensors of chemical, thermal, and mechanical noxious stimuli to evoke the pain and itch sensations. Among them are the TRPA1 channel, members of the vanilloid subfamily （TRPV1, TRPV3, and TRPV4）, and finally members of the melastatin group （TRPM2, TRPM3, and TRPMS）. Given that pain and itch are pro-survival, evolutionarily-honed protective mechanisms, care has to be exercised when developing inhibitory/modulatory com- pounds targeting specific pain/itch-TRPs so that physio- logical protective mechanisms are not disabled to a degree that stimulus-mediated injury can occur. Such events have impeded the development of safe and effective TRPV1- modulating compounds and have diverted substantial resources. A beneficial outcome can be readily accom- plished via simple dosing strategies, and also by incorpo- rating medicinal chemistry design features during compound design and synthesis. Beyond clinical use, where compounds that target more than one channel might have a place and possibly have advantageous features, highly specific and high-potency compounds will be helpful in mechanistic discovery at the structure-function level.展开更多
Farnesoid X receptor （FXR） is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid, cholesterol, lipid, and glucose metab...Farnesoid X receptor （FXR） is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid, cholesterol, lipid, and glucose metabolism. Therefore, FXR is a potential drug target for a number of metabolic disorders, especially those related to the metabolic syndrome. More recently, our group and others have extended the functions of FXR to more than metabolic regulation, which include anti-bacterial growth in intestine, liver regeneration, and hepatocarcinogenesis. These new findings suggest that FXR has much broader roles than previously thought, and also higi.light FXR as a drug target for multiple diseases. This review summarizes the basic information of FXR but focuses on its new functions.展开更多
AIM: To identify signaling pathways and genes that initiate and commit hepatic stellate cells (HSCs) to transdifferentiation. METHODS: Primary HSCs were isolated from male Sprague-Dawley rats and cultured on plastic f...AIM: To identify signaling pathways and genes that initiate and commit hepatic stellate cells (HSCs) to transdifferentiation. METHODS: Primary HSCs were isolated from male Sprague-Dawley rats and cultured on plastic for 0-10 d. Gene expression was assessed daily (quiescent to day 10 culture-activation) by real time polymerase chain reaction and data clustered using AMADA software. The significance of JAK/STAT signaling to HSC transdifferentiation was determined by treating cells with a JAK2 inhibitor. RESULTS: Genetic cluster analyses, based on expression of these 21 genes, showed similar expression profiles on days 1-3, days 5 and 6, and days 7-10, while freshly isolated cells (day Q) and day 4 cells were genotypically distinct from any of the other days. Additionally, gene expression clustering revealed strong upregulation of interleukin-6, JAK2 and STAT3 mRNA in the early stages of activation. Inhibition of the JAK/STAT signaling pathway impeded the morphological transdifferentiation of HSCs which correlated with decreased mRNA expression of several profibrotic genes including collagens, α-SMA, PDGFR and TGFβR. CONCLUSION: These data demonstrate unique clustered genetic profiles during the daily progression of HSC transdifferentiation and that JAK/STAT signaling may be critical in the early stages of transdifferentiation.展开更多
Hydrogen sulfide （H2S） is a gasotransmitter that regulates cardiovascular functions. The present study aimed to determine the protective effect of slow-releasing H2S donor GYY4137 on myocardial ischemia and reperfus...Hydrogen sulfide （H2S） is a gasotransmitter that regulates cardiovascular functions. The present study aimed to determine the protective effect of slow-releasing H2S donor GYY4137 on myocardial ischemia and reperfusion （I/R） injury and to investigate the possible signaling mechanisms involved. Male Sprague-Dawley rats were treated with GYY4137 at 12.5 mg/（kg.day）, 25 mg/（kg.day） or 50 mg/（kg.day） intraperitoneally for 7 days. Then, rats were subjected to 30 minutes of left anterior descending coronary artery occlusion followed by reperfusion for 24 hours. We found that GYY4137 increased the cardiac ejection fraction and fractional shortening, reduced the ischemia area, alleviated histological injury and decreased plasma creatine kinase after myocardial I/R. Both H2S concentration in plasma and cystathionine-γ-lyase （CSE） activity in the myocardium were enhanced in the GYY4137 treated groups. GYY4137 also decreased malondialdehyde and myeloperoxidase levels in serum, attenuated superoxide anion level and suppressed phosphorylation of mitogen activated protein kinases in the myocardium after I/R. Meanwhile, GYY4137 increased the expression of Bcl-2 but decreased the expression of Bax, caspase-3 activity and apoptosis in the myocardium. The data suggest that GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis.展开更多
AIM To identify health and psychosocial problems associated with bullying victimization and conduct a meta-analysis summarizing the causal evidence.METHODS A systematic review was conducted using Pub Med, EMBASE, ERIC...AIM To identify health and psychosocial problems associated with bullying victimization and conduct a meta-analysis summarizing the causal evidence.METHODS A systematic review was conducted using Pub Med, EMBASE, ERIC and Psyc INFO electronic databases up to 28 February 2015. The study included published longitudinal and cross-sectional articles that examined health and psychosocial consequences of bullying victimization. All meta-analyses were based on qualityeffects models. Evidence for causality was assessed using Bradford Hill criteria and the grading system developed by the World Cancer Research Fund.RESULTS Out of 317 articles assessed for eligibility, 165 satisfied the predetermined inclusion criteria for meta-analysis.Statistically significant associations were observed between bullying victimization and a wide range of adverse health and psychosocial problems. The evidence was strongest for causal associations between bullying victimization and mental health problems such as depression, anxiety, poor general health and suicidal ideation and behaviours. Probable causal associations existed between bullying victimization and tobacco and illicit drug use. CONCLUSION Strong evidence exists for a causal relationship between bullying victimization, mental health problems and substance use. Evidence also exists for associations between bullying victimization and other adverse health and psychosocial problems, however, there is insufficient evidence to conclude causality. The strong evidence that bullying victimization is causative of mental illness highlights the need for schools to implement effective interventions to address bullying behaviours.展开更多
Sequencing data from 10 species show that a plant hexokinase （HXK） family contains 5-11 genes. Functionally, a given family can include metabolic catalysts, glucose signaling proteins, and non-catalytic, apparent re...Sequencing data from 10 species show that a plant hexokinase （HXK） family contains 5-11 genes. Functionally, a given family can include metabolic catalysts, glucose signaling proteins, and non-catalytic, apparent regulatory enzyme homologs. This study has two goals. The first aim is to develop a predictive method to determine which HXK proteins within a species have which type of function. The second aim is to determine whether HXK-dependent glucose signaling proteins occur among more primitive plants, as well as among angiosperms. Using a molecular phylogeny ap- proach, combined with selective experimental testing, we found that non-catalytic HXK homologs might occur in all plants, including the relatively primitive Selaginella moellendorffi. We also found that different lineages of angiosperm HXKs have apparent conserved features for catalytic activity and for sub-cellular targeting. Most higher-plant HXKs are expressed predominantly at mitochondria, with HXKs of one lineage occurring in the plastid, and HXKs of one monocot lineage occurring in the cytosol. Using protoplast transient expression assays, we found that HXK glucose signaling pro- teins occur likely in all higher plants and in S. moellendorffi as well. Thus, the use of glucose by plant HXK isoforms in metabolism and/or as a regulatory metabolite occurs as widespread, conserved processes.展开更多
AIM:Hydrogen sulfide (H2S) is a prominent gaseous constituent of the gastrointestinal (GI) tract with known cytotoxic properties. Endogenous concentrations of H2S are reported to range between 0.2-3.4 mmol/L in the GI...AIM:Hydrogen sulfide (H2S) is a prominent gaseous constituent of the gastrointestinal (GI) tract with known cytotoxic properties. Endogenous concentrations of H2S are reported to range between 0.2-3.4 mmol/L in the GI tract of mice and humans. Considering such high levels we speculate that, at non-toxic concentrations, H2S may interact with chemical agents and alter the response of colonic epithelium cells to such compounds. The GI tract is a major site for the absorption of phytochemical constituents such as isothiocyanates, flavonoids, and carotenoids, with each group having a role in the prevention of human diseases such as colon cancer. The chemopreventative properties of the phytochemical agent p-phenyethyl isothiocyanate (PEITC) are well recognized. However, little is currently known about the physiological or biochemical factors present in the GI tract that may influence the biological properties of ITCs. The current study was undertaken to determine the effects of H2S on PEITC mediated apoptosis in colon cancer cells. METHODS: Induction of apoptosis by PEITC in human colon cancer HCT116 cells was assessed using classic apoptotic markers namely SubGl population analysis, caspase-3 like activity and nuclear fragmentation and condensation coupled with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide) viability assay and LDH leakage. RESULTS: PEITC significantly induced apoptosis in HCT116 cells as assessed by SubGl population formation, nuclear condensation, LDH leakage and caspase-3 activity after 24 h, these data being significant from control groups (P<0.01). In contrast, co-treatment of cells with physiological concentrations of H2S (0.1-1 mmol/L) prevented PEITC mediated apoptosis as assessed using the parameters described. CONCLUSION: PEITC effectively induced cell death in the human adenocarcinoma cell line HCT116 in vitro through classic apoptotic mechanisms. However, in the presence of H2S, apoptosis was abolished. These data suggest that H2S may play a significant role in the 展开更多
Ascites is a pathologic accumulation of peritoneal fluidcommonly observed in decompensated cirrhotic states. Its causes are multi-factorial, but principally involve significant volume and hormonal dysregulation in the...Ascites is a pathologic accumulation of peritoneal fluidcommonly observed in decompensated cirrhotic states. Its causes are multi-factorial, but principally involve significant volume and hormonal dysregulation in the setting of portal hypertension. The diagnosis of ascites is considered in cirrhotic patients given a constellation of clinical and laboratory findings, and ultimately confirmed, with insight into etiology, by imaging and paracentesis procedures. Treatment for ascites is multimodal including dietary sodium restriction, pharmacologic therapies, diagnostic and therapeutic paracentesis, and in certain cases transjugular intra-hepatic portosystemic shunt. Ascites is associated with numerous complications including spontaneous bacterial peritonitis, hepato-hydrothorax and hepatorenal syndrome. Given the complex nature of ascites and associatedcomplications, it is not surprising that it heralds increased morbidity and mortality in cirrhotic patients and increased cost-utilization upon the health-care system. This review will detail the pathophysiology of cirrhotic ascites, common complications derived from it, and pertinent treatment modalities.展开更多
Shadow is one of the major problems in remotely sensed imagery which hampers the accuracy of information extraction and change detection.In these images,shadow is generally produced by different objects,namely,cloud,m...Shadow is one of the major problems in remotely sensed imagery which hampers the accuracy of information extraction and change detection.In these images,shadow is generally produced by different objects,namely,cloud,mountain and urban materials.The shadow correction process consists of two steps:detection and de-shadowing.This paper reviews a range of techniques for both steps,focusing on urban regions(urban shadows),mountainous areas(topographic shadow),cloud shadows and composite shadows.Several issues including the problems and the advantages of those algorithms are discussed.In recent years,thresholding and recovery techniques have become important for shadow detection and de-shadowing,respectively.Research on shadow correction is still an important topic,particularly for urban regions(in high spatial resolution data) and mountainous forest(in high and medium spatial resolution data).Moreover,new algorithms are needed for shadow correction,especially given the advent of new satellite images.展开更多
After decades of research and development, the WSR-88 D(NEXRAD) network in the United States was upgraded with dual-polarization capability, providing polarimetric radar data(PRD) that have the potential to improve we...After decades of research and development, the WSR-88 D(NEXRAD) network in the United States was upgraded with dual-polarization capability, providing polarimetric radar data(PRD) that have the potential to improve weather observations,quantification, forecasting, and warnings. The weather radar networks in China and other countries are also being upgraded with dual-polarization capability. Now, with radar polarimetry technology having matured, and PRD available both nationally and globally, it is important to understand the current status and future challenges and opportunities. The potential impact of PRD has been limited by their oftentimes subjective and empirical use. More importantly, the community has not begun to regularly derive from PRD the state parameters, such as water mixing ratios and number concentrations, used in numerical weather prediction(NWP) models.In this review, we summarize the current status of weather radar polarimetry, discuss the issues and limitations of PRD usage, and explore potential approaches to more efficiently use PRD for quantitative precipitation estimation and forecasting based on statistical retrieval with physical constraints where prior information is used and observation error is included. This approach aligns the observation-based retrievals favored by the radar meteorology community with the model-based analysis of the NWP community. We also examine the challenges and opportunities of polarimetric phased array radar research and development for future weather observation.展开更多
Carotene pigments in flowers and fruits are distinct features related to fitness advantages such as attracting insects forpollination and birds for seed dispersal.In papaya,the flesh color of the fruit is considered a...Carotene pigments in flowers and fruits are distinct features related to fitness advantages such as attracting insects forpollination and birds for seed dispersal.In papaya,the flesh color of the fruit is considered a quality trait that correlateswith nutritional value and is linked to shelf-life of the fruit.To elucidate the carotenoid biosynthesis pathway in papaya,we took a candidate gene approach to clone the lycopene β-cyclase gene,LCY-B.A papaya LCY-B ortholog,cpLCY-B,was successfully identified from both cDNA and bacterial artificial chromosome(BAC)libraries and complete genomicsequence was obtained from the positive BAC including the promoter region.This cpLCY-B shared 80% amino acididentity with citrus LCY-B.However,full genomic sequences from both yellow- and red-fleshed papaya were identical.Quantitative real-time PCR(qPCR)revealed similar levels of expression at six different maturing stages of fruits forboth yellow-and red-fleshed genotypes.Further expression analyses of cpLCY-B showed that its expression levels wereseven- and three-fold higher in leaves and,respectively,flowers than in fruits,suggesting that cpLCY-B is down-regulatedduring the fruit ripening process.展开更多
Background: Infectious diseases associated with Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV) continue to pose significant public health challenges that necessitate continuou...Background: Infectious diseases associated with Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV) continue to pose significant public health challenges that necessitate continuous surveillance and interventions. This study investigates the prevalence of HIV, HBV and HCV infections within the academic community of Rivers State University, Port Harcourt, Nigeria. Given the potential for transmission in university settings and the importance of early detection and intervention, this research explores the extent of these infections and evaluates the outcomes of a medical outreach program aimed at addressing them. Methodology: A cross-sectional study design was employed to recruit 513 participants using a convenience sampling approach between the 20<sup>th</sup> and 22<sup>nd</sup> of April 2022. Participants included students and staff members who voluntarily consented to the medical outreach and study. Serological assays were utilized to identify HIV, HBV and HCV infections. The medical outreach program’s design, implementation, and outcomes were evaluated, focusing on testing uptake, counselling utilization, and linkage to care. Statistical analysis employed GraphPad Prism version 9 software. Result: The study revealed low prevalence rates of HIV (0.6%), HBV (1.2%), and HCV (0.6%) infections within the university population. Age-based analysis indicated a slightly higher prevalence in the 15 - 24 age group. Gender-wise, HBV showed a marginal difference, with 1.3% among females and 0.9% among males. The medical outreach program achieved a testing uptake of 80.8%, with 75% utilizing counselling services, and 75% of those identified with infections successfully linked to care. Conclusion: This study provides valuable insights into the prevalence of infections and the effectiveness of a medical outreach program within a university community. While low prevalence rates are encouraging, the findings emphasize the continued importance of awareness and prevention efforts. The succes展开更多
With a high penetration of wind turbines,the proportion of synchronous generation in the power system will be reduced at times,thus creating operating difficulties especially during frequency events.Therefore,it is an...With a high penetration of wind turbines,the proportion of synchronous generation in the power system will be reduced at times,thus creating operating difficulties especially during frequency events.Therefore,it is anticipated that many grid operators will demand inertia response from wind turbines.In this article,different ways for emulating inertia response in full-rated power converter-based wind turbines equipped with permanent magnet synchronous generators are considered.Supplementary control signals are added to the controller of the wind turbine to extract stored energy from the rotating mass and DC-link capacitors.Simulations in MATLAB/Simulink show that the inertia response is improved by adding a term proportional to the rate of change of frequency and by extracting the stored energy in the DC-link capacitors.展开更多
基金supported by the National Institutes of Health,USA(DE018549,UL1TR001117,P30AR066527,and AR48182 to WL,AR48182-S1 to WL as co-investigatorF33DE024668 and K12DE022793 to YC)+1 种基金the US Department of Defense(W81XWH-13-1-0299 to WL)the Harrington Discovery Institute,Cleveland OH(to WL)
文摘Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular sensors of chemical, thermal, and mechanical noxious stimuli to evoke the pain and itch sensations. Among them are the TRPA1 channel, members of the vanilloid subfamily （TRPV1, TRPV3, and TRPV4）, and finally members of the melastatin group （TRPM2, TRPM3, and TRPMS）. Given that pain and itch are pro-survival, evolutionarily-honed protective mechanisms, care has to be exercised when developing inhibitory/modulatory com- pounds targeting specific pain/itch-TRPs so that physio- logical protective mechanisms are not disabled to a degree that stimulus-mediated injury can occur. Such events have impeded the development of safe and effective TRPV1- modulating compounds and have diverted substantial resources. A beneficial outcome can be readily accom- plished via simple dosing strategies, and also by incorpo- rating medicinal chemistry design features during compound design and synthesis. Beyond clinical use, where compounds that target more than one channel might have a place and possibly have advantageous features, highly specific and high-potency compounds will be helpful in mechanistic discovery at the structure-function level.
文摘Farnesoid X receptor （FXR） is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid, cholesterol, lipid, and glucose metabolism. Therefore, FXR is a potential drug target for a number of metabolic disorders, especially those related to the metabolic syndrome. More recently, our group and others have extended the functions of FXR to more than metabolic regulation, which include anti-bacterial growth in intestine, liver regeneration, and hepatocarcinogenesis. These new findings suggest that FXR has much broader roles than previously thought, and also higi.light FXR as a drug target for multiple diseases. This review summarizes the basic information of FXR but focuses on its new functions.
基金Supported by National Institutes of Health Grant RO1 AA014891
文摘AIM: To identify signaling pathways and genes that initiate and commit hepatic stellate cells (HSCs) to transdifferentiation. METHODS: Primary HSCs were isolated from male Sprague-Dawley rats and cultured on plastic for 0-10 d. Gene expression was assessed daily (quiescent to day 10 culture-activation) by real time polymerase chain reaction and data clustered using AMADA software. The significance of JAK/STAT signaling to HSC transdifferentiation was determined by treating cells with a JAK2 inhibitor. RESULTS: Genetic cluster analyses, based on expression of these 21 genes, showed similar expression profiles on days 1-3, days 5 and 6, and days 7-10, while freshly isolated cells (day Q) and day 4 cells were genotypically distinct from any of the other days. Additionally, gene expression clustering revealed strong upregulation of interleukin-6, JAK2 and STAT3 mRNA in the early stages of activation. Inhibition of the JAK/STAT signaling pathway impeded the morphological transdifferentiation of HSCs which correlated with decreased mRNA expression of several profibrotic genes including collagens, α-SMA, PDGFR and TGFβR. CONCLUSION: These data demonstrate unique clustered genetic profiles during the daily progression of HSC transdifferentiation and that JAK/STAT signaling may be critical in the early stages of transdifferentiation.
基金supported by grants from the National Natural Science Foundation of China(Grant No.81170083,81400203)Universities Natural Science Research Project of Jiangsu Province(No.10KJA310033)+1 种基金Major Science and Technology Development Fund Project of Nanjing Medical University(2011NJMU264)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions
文摘Hydrogen sulfide （H2S） is a gasotransmitter that regulates cardiovascular functions. The present study aimed to determine the protective effect of slow-releasing H2S donor GYY4137 on myocardial ischemia and reperfusion （I/R） injury and to investigate the possible signaling mechanisms involved. Male Sprague-Dawley rats were treated with GYY4137 at 12.5 mg/（kg.day）, 25 mg/（kg.day） or 50 mg/（kg.day） intraperitoneally for 7 days. Then, rats were subjected to 30 minutes of left anterior descending coronary artery occlusion followed by reperfusion for 24 hours. We found that GYY4137 increased the cardiac ejection fraction and fractional shortening, reduced the ischemia area, alleviated histological injury and decreased plasma creatine kinase after myocardial I/R. Both H2S concentration in plasma and cystathionine-γ-lyase （CSE） activity in the myocardium were enhanced in the GYY4137 treated groups. GYY4137 also decreased malondialdehyde and myeloperoxidase levels in serum, attenuated superoxide anion level and suppressed phosphorylation of mitogen activated protein kinases in the myocardium after I/R. Meanwhile, GYY4137 increased the expression of Bcl-2 but decreased the expression of Bax, caspase-3 activity and apoptosis in the myocardium. The data suggest that GYY4137 protects against myocardial ischemia and reperfusion injury by attenuating oxidative stress and apoptosis.
文摘AIM To identify health and psychosocial problems associated with bullying victimization and conduct a meta-analysis summarizing the causal evidence.METHODS A systematic review was conducted using Pub Med, EMBASE, ERIC and Psyc INFO electronic databases up to 28 February 2015. The study included published longitudinal and cross-sectional articles that examined health and psychosocial consequences of bullying victimization. All meta-analyses were based on qualityeffects models. Evidence for causality was assessed using Bradford Hill criteria and the grading system developed by the World Cancer Research Fund.RESULTS Out of 317 articles assessed for eligibility, 165 satisfied the predetermined inclusion criteria for meta-analysis.Statistically significant associations were observed between bullying victimization and a wide range of adverse health and psychosocial problems. The evidence was strongest for causal associations between bullying victimization and mental health problems such as depression, anxiety, poor general health and suicidal ideation and behaviours. Probable causal associations existed between bullying victimization and tobacco and illicit drug use. CONCLUSION Strong evidence exists for a causal relationship between bullying victimization, mental health problems and substance use. Evidence also exists for associations between bullying victimization and other adverse health and psychosocial problems, however, there is insufficient evidence to conclude causality. The strong evidence that bullying victimization is causative of mental illness highlights the need for schools to implement effective interventions to address bullying behaviours.
文摘Sequencing data from 10 species show that a plant hexokinase （HXK） family contains 5-11 genes. Functionally, a given family can include metabolic catalysts, glucose signaling proteins, and non-catalytic, apparent regulatory enzyme homologs. This study has two goals. The first aim is to develop a predictive method to determine which HXK proteins within a species have which type of function. The second aim is to determine whether HXK-dependent glucose signaling proteins occur among more primitive plants, as well as among angiosperms. Using a molecular phylogeny ap- proach, combined with selective experimental testing, we found that non-catalytic HXK homologs might occur in all plants, including the relatively primitive Selaginella moellendorffi. We also found that different lineages of angiosperm HXKs have apparent conserved features for catalytic activity and for sub-cellular targeting. Most higher-plant HXKs are expressed predominantly at mitochondria, with HXKs of one lineage occurring in the plastid, and HXKs of one monocot lineage occurring in the cytosol. Using protoplast transient expression assays, we found that HXK glucose signaling pro- teins occur likely in all higher plants and in S. moellendorffi as well. Thus, the use of glucose by plant HXK isoforms in metabolism and/or as a regulatory metabolite occurs as widespread, conserved processes.
文摘AIM:Hydrogen sulfide (H2S) is a prominent gaseous constituent of the gastrointestinal (GI) tract with known cytotoxic properties. Endogenous concentrations of H2S are reported to range between 0.2-3.4 mmol/L in the GI tract of mice and humans. Considering such high levels we speculate that, at non-toxic concentrations, H2S may interact with chemical agents and alter the response of colonic epithelium cells to such compounds. The GI tract is a major site for the absorption of phytochemical constituents such as isothiocyanates, flavonoids, and carotenoids, with each group having a role in the prevention of human diseases such as colon cancer. The chemopreventative properties of the phytochemical agent p-phenyethyl isothiocyanate (PEITC) are well recognized. However, little is currently known about the physiological or biochemical factors present in the GI tract that may influence the biological properties of ITCs. The current study was undertaken to determine the effects of H2S on PEITC mediated apoptosis in colon cancer cells. METHODS: Induction of apoptosis by PEITC in human colon cancer HCT116 cells was assessed using classic apoptotic markers namely SubGl population analysis, caspase-3 like activity and nuclear fragmentation and condensation coupled with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide) viability assay and LDH leakage. RESULTS: PEITC significantly induced apoptosis in HCT116 cells as assessed by SubGl population formation, nuclear condensation, LDH leakage and caspase-3 activity after 24 h, these data being significant from control groups (P<0.01). In contrast, co-treatment of cells with physiological concentrations of H2S (0.1-1 mmol/L) prevented PEITC mediated apoptosis as assessed using the parameters described. CONCLUSION: PEITC effectively induced cell death in the human adenocarcinoma cell line HCT116 in vitro through classic apoptotic mechanisms. However, in the presence of H2S, apoptosis was abolished. These data suggest that H2S may play a significant role in the
文摘Ascites is a pathologic accumulation of peritoneal fluidcommonly observed in decompensated cirrhotic states. Its causes are multi-factorial, but principally involve significant volume and hormonal dysregulation in the setting of portal hypertension. The diagnosis of ascites is considered in cirrhotic patients given a constellation of clinical and laboratory findings, and ultimately confirmed, with insight into etiology, by imaging and paracentesis procedures. Treatment for ascites is multimodal including dietary sodium restriction, pharmacologic therapies, diagnostic and therapeutic paracentesis, and in certain cases transjugular intra-hepatic portosystemic shunt. Ascites is associated with numerous complications including spontaneous bacterial peritonitis, hepato-hydrothorax and hepatorenal syndrome. Given the complex nature of ascites and associatedcomplications, it is not surprising that it heralds increased morbidity and mortality in cirrhotic patients and increased cost-utilization upon the health-care system. This review will detail the pathophysiology of cirrhotic ascites, common complications derived from it, and pertinent treatment modalities.
基金Under the auspices of National Technology Research and Development Program of China(No.2006BAJ05A02)National Natural Science Foundation of China(No.31172023)
文摘Shadow is one of the major problems in remotely sensed imagery which hampers the accuracy of information extraction and change detection.In these images,shadow is generally produced by different objects,namely,cloud,mountain and urban materials.The shadow correction process consists of two steps:detection and de-shadowing.This paper reviews a range of techniques for both steps,focusing on urban regions(urban shadows),mountainous areas(topographic shadow),cloud shadows and composite shadows.Several issues including the problems and the advantages of those algorithms are discussed.In recent years,thresholding and recovery techniques have become important for shadow detection and de-shadowing,respectively.Research on shadow correction is still an important topic,particularly for urban regions(in high spatial resolution data) and mountainous forest(in high and medium spatial resolution data).Moreover,new algorithms are needed for shadow correction,especially given the advent of new satellite images.
基金supported by the NOAA (Grant Nos. NA16AOR4320115 and NA11OAR4320072)NSF (Grant No. AGS-1341878)
文摘After decades of research and development, the WSR-88 D(NEXRAD) network in the United States was upgraded with dual-polarization capability, providing polarimetric radar data(PRD) that have the potential to improve weather observations,quantification, forecasting, and warnings. The weather radar networks in China and other countries are also being upgraded with dual-polarization capability. Now, with radar polarimetry technology having matured, and PRD available both nationally and globally, it is important to understand the current status and future challenges and opportunities. The potential impact of PRD has been limited by their oftentimes subjective and empirical use. More importantly, the community has not begun to regularly derive from PRD the state parameters, such as water mixing ratios and number concentrations, used in numerical weather prediction(NWP) models.In this review, we summarize the current status of weather radar polarimetry, discuss the issues and limitations of PRD usage, and explore potential approaches to more efficiently use PRD for quantitative precipitation estimation and forecasting based on statistical retrieval with physical constraints where prior information is used and observation error is included. This approach aligns the observation-based retrievals favored by the radar meteorology community with the model-based analysis of the NWP community. We also examine the challenges and opportunities of polarimetric phased array radar research and development for future weather observation.
文摘Carotene pigments in flowers and fruits are distinct features related to fitness advantages such as attracting insects forpollination and birds for seed dispersal.In papaya,the flesh color of the fruit is considered a quality trait that correlateswith nutritional value and is linked to shelf-life of the fruit.To elucidate the carotenoid biosynthesis pathway in papaya,we took a candidate gene approach to clone the lycopene β-cyclase gene,LCY-B.A papaya LCY-B ortholog,cpLCY-B,was successfully identified from both cDNA and bacterial artificial chromosome(BAC)libraries and complete genomicsequence was obtained from the positive BAC including the promoter region.This cpLCY-B shared 80% amino acididentity with citrus LCY-B.However,full genomic sequences from both yellow- and red-fleshed papaya were identical.Quantitative real-time PCR(qPCR)revealed similar levels of expression at six different maturing stages of fruits forboth yellow-and red-fleshed genotypes.Further expression analyses of cpLCY-B showed that its expression levels wereseven- and three-fold higher in leaves and,respectively,flowers than in fruits,suggesting that cpLCY-B is down-regulatedduring the fruit ripening process.
文摘Background: Infectious diseases associated with Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV) continue to pose significant public health challenges that necessitate continuous surveillance and interventions. This study investigates the prevalence of HIV, HBV and HCV infections within the academic community of Rivers State University, Port Harcourt, Nigeria. Given the potential for transmission in university settings and the importance of early detection and intervention, this research explores the extent of these infections and evaluates the outcomes of a medical outreach program aimed at addressing them. Methodology: A cross-sectional study design was employed to recruit 513 participants using a convenience sampling approach between the 20<sup>th</sup> and 22<sup>nd</sup> of April 2022. Participants included students and staff members who voluntarily consented to the medical outreach and study. Serological assays were utilized to identify HIV, HBV and HCV infections. The medical outreach program’s design, implementation, and outcomes were evaluated, focusing on testing uptake, counselling utilization, and linkage to care. Statistical analysis employed GraphPad Prism version 9 software. Result: The study revealed low prevalence rates of HIV (0.6%), HBV (1.2%), and HCV (0.6%) infections within the university population. Age-based analysis indicated a slightly higher prevalence in the 15 - 24 age group. Gender-wise, HBV showed a marginal difference, with 1.3% among females and 0.9% among males. The medical outreach program achieved a testing uptake of 80.8%, with 75% utilizing counselling services, and 75% of those identified with infections successfully linked to care. Conclusion: This study provides valuable insights into the prevalence of infections and the effectiveness of a medical outreach program within a university community. While low prevalence rates are encouraging, the findings emphasize the continued importance of awareness and prevention efforts. The succes
基金This study was supported by the Low Carbon Research Institute(LCRI).
文摘With a high penetration of wind turbines,the proportion of synchronous generation in the power system will be reduced at times,thus creating operating difficulties especially during frequency events.Therefore,it is anticipated that many grid operators will demand inertia response from wind turbines.In this article,different ways for emulating inertia response in full-rated power converter-based wind turbines equipped with permanent magnet synchronous generators are considered.Supplementary control signals are added to the controller of the wind turbine to extract stored energy from the rotating mass and DC-link capacitors.Simulations in MATLAB/Simulink show that the inertia response is improved by adding a term proportional to the rate of change of frequency and by extracting the stored energy in the DC-link capacitors.
