Prodrugs need to be converted to active drugs to exert their pharmacological activities.Identifying the direct targets of active drugs is essential to elucidate the pharmacological mechanisms of prodrugs,but remains c...Prodrugs need to be converted to active drugs to exert their pharmacological activities.Identifying the direct targets of active drugs is essential to elucidate the pharmacological mechanisms of prodrugs,but remains challenging,especially for active drugs with low stability.展开更多
Inbreeding increases genome homozygosity within populations,which can exacerbate inbreeding depression by exposing homozygous deleterious alleles that are responsible for declines in fitness traits.In small population...Inbreeding increases genome homozygosity within populations,which can exacerbate inbreeding depression by exposing homozygous deleterious alleles that are responsible for declines in fitness traits.In small populations,genetic purging that occurs under the pressure of natural selection acts as an opposing force,contributing to a reduction of deleterious alleles.Both inbreeding and genetic purging are paramount in the field of conservation genomics.The Amur tiger(Panthera tigris altaica)lives in small populations in the forests of Northeast Asia and is among the most endangered animals on the planet.Using genome-wide assessment and comparison,we reveal substantially higher and more extensive inbreeding in wild Amur tigers(F_(ROH)=0.50)than in captive individuals(F_(ROH)=0.24).However,a relatively reduced number of lossof-function mutations in wild Amur tigers is observed compared to captive individuals,indicating genetic purging of inbreeding load with relatively large-effect alleles.The higher ratio of homozygous mutation load and number of fixed damaging alleles in the wild population indicates a less-efficient genetic purging,with purifying selection also contributing to this process.These findings provide valuable insights for the future conservation of Amur tigers.展开更多
In photothermal power(solar energy)generation systems,purging residual molten salt from pipelines using highpressure gas poses a significant challenge,particularly in clearing the bottom of regulating valves.Ineffecti...In photothermal power(solar energy)generation systems,purging residual molten salt from pipelines using highpressure gas poses a significant challenge,particularly in clearing the bottom of regulating valves.Ineffective purging can lead to crystallization of the molten salt,resulting in blockages.To address this issue,understanding the gas-liquid two-phase flow dynamics during high-pressure gas purging is crucial.This study utilizes the Volume of Fluid(VOF)model and adaptive dynamic grids to simulate the gas-liquid two-phase flow during the purging process in a DN50 PN50 conventional molten salt regulating valve.Initially,the reliability of the CFD simulations is validated through comparisons with experimental data and findings from the literature.Subsequently,simulation experiments are conducted to analyze the effects of various factors,including purge flow rates,initial liquid accumulation masses,purge durations,and the profiles of the valve bottom flow channels.The results indicate that the purging process comprises four distinct stages:Initial violent surge stage,liquid discharge stage,liquid partial fallback stage,liquid dissipation stage.For an initial liquid height of 17 mm at the bottom of the valve,the critical purge flow rate lies between 3 and 5 m/s.Notably,the critical purge flow rate is independent of the initial liquid accumulation mass.As the purge gas flow rate increases,the volume of liquid discharged also increases.Beyond the critical purge flow rate,higher purge gas velocities lead to shorter purge durations.Interestingly,the residual liquid mass after purging remains unaffected by the initial liquid accumulation.Additionally,the flow channel profile at the bottom of the valve significantly influences both the critical purge speed and the efficiency of the purging process.展开更多
Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operati...Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operational costs,particularly for hydrocarbons with high boiling points or strong host-vip interactions[2].This is the same case in the newly-developed macrocyclebased crystalline adsorbents,namely nonporous adaptive crystals(NACs).To address these challenges,a recent study published in Angewandte Chemie International Edition by Jie,Ma,and co-workers reported an innovative molecular-"squeeze"triggered desorption mechanism in NACs[3-5].Specifically,ethyl acetate(EA)triggers vip desorption without penetrating the crystal pores or voids.Instead,EA molecules interact with the crystal surface through supramolecular forces,causing the adaptive closure of voids and the subsequent release of vip molecules.Unlike conventional sponges that rely on mechanical squeeze to deform themselves in the bulk for vip release,these macrocycle crystals undergo structural deformation at the molecular level and condensed phase when exposed to vaporized molecules.Because of the similar behavior between sponges and such NACs,the authors name them as sponge-likemacrocyclecrystals.展开更多
The pollution of VOCs was studied on both side of highway.With the determination method of purge and trap concentration coupled with gas chromatography-mass spectrometry,we found that the degree of pollution near the ...The pollution of VOCs was studied on both side of highway.With the determination method of purge and trap concentration coupled with gas chromatography-mass spectrometry,we found that the degree of pollution near the highway was not very bad.展开更多
Pre-procedural cleansing of the bowel can maximize the effectiveness and efficiency of colonoscopy.Yet,efficacy of the current gold standard colonic preparation method-high-volume oral administration of purgative agen...Pre-procedural cleansing of the bowel can maximize the effectiveness and efficiency of colonoscopy.Yet,efficacy of the current gold standard colonic preparation method-high-volume oral administration of purgative agents 12-24 h prior to the procedure-is limited by several factors,such as patient compliance(due to poor palatability and inconvenience of the dosing regimen)and risks of complications(due to drug interactions or intolerance).Attempts to resolve these limitations have included providing adjunctive agents and methods to promote the colonic cleansing ability of the principal purgative agent,with the aim of lessening unpleasant side effects(such as bloating)and reducing the large ingested volume requirement.Several promising adjunctive agents are bisacodyl,magnesium citrate,senna,simethicone,metoclopramide,and prokinetics,and each are being investigated for their potential.This review provides an up to date summary of the reported investigations into the potencies and weaknesses of the key adjuncts currently being applied in clinic as supplements to the traditional bowel preparation agents.While the comparative analysis ofthese adjuncts showed that no single agent or method has yet achieved the goal of completely overcoming the limitations of the current gold standard preparation method,they at least provide endoscopists with an array of alternatives to help improve the suboptimal efficacy of the main cleansing solutions when used alone.To aid in this clinical endeavor,a subjective grade was assigned to each adjunct to indicate its practical value.In addition,the systematic review of the currently available agents and methods provides insight into the features of each that may be overcome or exploited to create novel drugs and strategies that may become adopted as effective bowel cleansing adjuncts or alternatives.展开更多
AIM:To investigate the changes in renal function at 12-24 mo in patients following sodium phosphate(NaP) preparation for screening colonoscopy.METHODS:We carried out a retrospective study on the results from patients ...AIM:To investigate the changes in renal function at 12-24 mo in patients following sodium phosphate(NaP) preparation for screening colonoscopy.METHODS:We carried out a retrospective study on the results from patients who received health check-up services as part of an employer-provided wellness program performed between August 2006 and May 2008 and who were followed up for 12-24 mo.Prior to screening colonoscopy,224 patients underwent bowel cleansing with NaP(NaP group) and 113 patients with polyethylene glycol(PEG group).The control group comprised 672 age-matched patients.We compared the changes in the creatinine levels and the glomerular filtration rates(GFRs) from baseline to 12-24 mo between the NaP,PEG,and control groups using two-way repeated measured analysis of variance.In addition,multivariate linear regression analysis was performed to assess the risk factors for a decreased GFR.RESULTS:The baseline mean serum creatinine level in the NaP,PEG,and control groups was 1.12 ± 0.15,1.12 ± 0.16,and 1.12 ± 0.15 mg/dL,which increased to 1.15 ± 0.15,1.15 ± 0.18,and 1.15 ± 0.15 mg/dL,respectively,after 12-24 mo.The baseline mean GFR in the NaP,PEG,and control groups was 69.0 ± 7.7,68.9 ± 8.0,and 69.6 ± 6.7 mL/min per 1.73 m2,which decreased to 66.5 ± 7.8,66.5 ± 8.3,and 67.4 ± 6.4 mL/min per 1.73 m2,respectively,after 12-24 mo.The changes in serum creatinine levels and GFRs were not significantly between the NaP,PEG,and control groups(P = 0.992 and P = 0.233,respectively).Using multivariate linear regression analysis,only the baseline GFR was associated with the change in GFR(P < 0.001).Indeed,the bowel preparations were not associated with the change in GFR(P = 0.297).CONCLUSION:NaP bowel preparation in subjects with normal renal function was not associated with renal injury,and NaP can thus be used safely for screening colonoscopy.展开更多
AIM To assess the cleansing efficacy and safety of a new Colon capsule endoscopy(CCE)bowel preparation regimen.METHODS This was a multicenter,prospective,randomized,controlled study comparing two CCE regimens.Subjects...AIM To assess the cleansing efficacy and safety of a new Colon capsule endoscopy(CCE)bowel preparation regimen.METHODS This was a multicenter,prospective,randomized,controlled study comparing two CCE regimens.Subjects were asymptomatic and average risk for colorectal cancer.The second generation CCE system(Pill Cam?COLON 2;Medtronic,Yoqneam,Israel)was utilized.Preparation regimens differed in the 1 st and 2 nd boosts with the Study regimen using oral sulfate solution(89 m L)with diatrizoate meglumine and diatrizoate sodium solution("diatrizoate solution")(boost 1=60 m L,boost 2=30 m L)and the Control regimen oral sulfate solution(89 m L)alone.The primary outcome was overall and segmental colon cleansing.Secondary outcomes included safety,polyp detection,colonic transit,CCE completion and capsule excretion≤12 h.RESULTS Both regimens had similar cleansing efficacy for the whole colon(Adequate:Study=75.9%,Control=77.3%;P=0.88)and individual segments.In the Study group,CCE completion was superior(Study=90.9%,Control=76.9%;P=0.048)and colonic transit was more often<40 min(Study=21.8%,Control=4%;P=0.0073).More Study regimen subjects experienced adverse events(Study=19.4%,Control=3.4%;P=0.0061),and this difference did not appear related to diatrizoate solution.Adverse events were primarily gastrointestinal in nature and no serious adverse events related either to the bowel preparation regimen or the capsule were observed.There was a trend toward higher polyp detection with the Study regimen,but this did not achieve statistical significance for any size category.Mean transit time through the entire gastrointestinal tract,from ingestion to excretion,was shorter with the Study regimen while mean colonic transit times were similar for both study groups.CONCLUSION A CCE bowel preparation regimen using oral sulfate solution and diatrizoate solution as a boost agent is effective,safe,and achieved superior CCE completion.展开更多
Rumex nepalensis Spreng.(Polygonaceae) commonly known as Nepal Dock has wide-spectrum therapeutic potencies and is extensively used for centuries in traditional medicine systems. The leaves of this plant are edible an...Rumex nepalensis Spreng.(Polygonaceae) commonly known as Nepal Dock has wide-spectrum therapeutic potencies and is extensively used for centuries in traditional medicine systems. The leaves of this plant are edible and a rich source of natural antioxidants. They act as a possible food supplement and are largely used in pharmaceutical industry. Extracts and metabolites from this plant exhibits pharmacological activities including anti-inflammatory, antioxidant, antibacterial, antifungal, antiviral, insecticidal, purgative, analgesic, antipyretic, anti-algal, central nervous system depressant, genotoxic, wound healing and skeletal muscle relaxant activity. Due to its remarkable biological activities, it has the potential to act as a rich source of drug against life threatening diseases. However, more studies are needed to scientifically validate the traditional uses of this plant, beside isolating and identifying their active principles and characterizing the mechanisms of action. We present herein a critical account of its botany, ecology, traditional uses, phytoconstituent profile and major pharmacological activities reported in recent years and therefore will provide a source of information on this plant for further studies.展开更多
Objective:To investigate the modulating role of methanol extract of Tephrosia vogelii leaves on acetylcholine(ACh)-induced contraction of isolated rabbit jejunum.Methods: Rabbit jejunum segment was removed and placed ...Objective:To investigate the modulating role of methanol extract of Tephrosia vogelii leaves on acetylcholine(ACh)-induced contraction of isolated rabbit jejunum.Methods: Rabbit jejunum segment was removed and placed in an organ bath containing Tyrode's solution, and its contractions were recorded isometrically.Results: ACh(2.0 × 10-10 g/m L) and the extract(2.0 × 10-4 g/m L) individually increased the frequency of contraction(mean ± SEM) of the isolated smooth muscle tissue by 47.6% ± 9.5% and 77.8% ± 66.5%, respectively. When ACh and the extract were combined, the frequency of contraction of the tissue was increased by 222.2% ± 25.9%, representing a 366.7% increase(P < 0.001) over the effect of ACh alone. Similarly, ACh(2.0 × 10-9 g/m L) and the extract individually increased significantly(P < 0.001) the amplitude of contraction of the tissue by 685.7% ± 61.1% and 455.2% ± 38.1%, respectively. When ACh and the extract were combined, the amplitude of contraction of the tissue rose by 1263.8% ± 69.0%, representing 84.3% increase over the ef ect of ACh alone. Conclusions: The findings demonstrate that methanol extract of Tephrosia vogelii leaves potentiates the contractile ef ect of ACh on intestinal smooth muscle, supporting the traditional claim that the plant is purgative.展开更多
In modern gas turbines, rim seal located between the stator-disc and rotor-disc is used to prevent hot-gas ingestion into the inner stage-gap of high pressure turbine. However, the purge flow supplied to the cavity th...In modern gas turbines, rim seal located between the stator-disc and rotor-disc is used to prevent hot-gas ingestion into the inner stage-gap of high pressure turbine. However, the purge flow supplied to the cavity through the rim seal interacts with the main flow, producing additional aerodynamic loss due to the mixing process which plays a significant role in the formation, development and evolution of downstream secondary flow. In this paper, a set of cascade representative of low aspect ratio turbine is selected to numerically investigate the influence of upstream cavity purge flow on the hub secondary flow structure and aerodynamic loss. Cascade with/without upstream cavity and four different purge mass flow rates are all taken into account in this simulation. Then, a deep insight into the loss mechanism of interaction between purge flow and main flow is gained. The results show that the presence of cavity and purge flow has a significant impact on the main flow which not only changes the vortex structure in both the passage and upstream cavity, but also alters the cascade exit flow angle distribution along the spanwise. Moreover, aerodynamic loss in the cascade rises with the increase of purge flow rate while the sealing effect is also enhanced. Therefore, the effect of upstream cavity purge flow must be considered in the process of turbine aerodynamic design. What is more, it is necessary to minimize the purge flow rate in order to reduce aerodynamic loss on the premise of satisfying cooling requirements.展开更多
At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell (PEMFC) deteriorates markedly. The object of this work is to study the degradation mechanism of key components o...At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell (PEMFC) deteriorates markedly. The object of this work is to study the degradation mechanism of key components of PEMFC-membrane-electrode assembly (MEA) and seek feasible measures to avoid degradation. The effect of freeze/thaw cycles on the structure of MEA is investigated based on porosity and SEM measurement. The performance of a single cell was also tested before and after repetitious freeze/thaw cycles. The experimental results indicated that the performance of a PEMFC decreased along with the total operating time as well as the pore size distribution shifting and micro configuration changing. However, when the redundant water had been removed by gas purging, the performance of the PEMFC stack was almost resumed when it experienced again the same subzero temperature test. These results show that it is necessary to remove the water in PEMFCs to maintain stable performance under subzero temperature and gas purging is proved to be the effective operation.展开更多
Aroma of Chinese steamed bread（CSB） is one of the important parameters that determines the overall quality attributes and consumer acceptance. However, the aroma profile of CSB still remains poorly understood, mainl...Aroma of Chinese steamed bread（CSB） is one of the important parameters that determines the overall quality attributes and consumer acceptance. However, the aroma profile of CSB still remains poorly understood, mainly because of relying on only a single method for aroma extraction in previous studies. Therefore, the objective of this study was to determine the volatile aroma compounds of five different samples of CSB using three different aroma extraction methods, namely solid-phase microextraction（SPME）, simultaneous distillation–extraction（SDE）, and purge and trap（PT）. All samples showed a unique aroma profile, which could be attributed to their unique microbial consortia.（E）-2-Nonenal and（E,E）-2,4-decadienal were the most prevalent aromatic compounds revealed by SDE, which have not been reported previously, while ethanol and acetic acid proved to be the most dominant compounds by both SPME and PT. Our approach of combining three different aroma extraction methods provided better insights into the aroma profile of CSB, which had remained largely unknown in previous studies.展开更多
A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. ...A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. Detection limit of 2.5 pmol of DMS in 25 mL sample, corresponding to 0.10 nmol/L, was achieved. Recoveries for dimethyl sulfur compounds were in the range of 68.6- 78.3%. The relative standard deviations （R.S.D.s） for DMS, DMSP and DMSO determination were 3.0, 5.4 and 7.4%, respectively.展开更多
Water disinfection is an essential process that provides safe water by inactivating pathogens that cause waterborne diseases. However, disinfectants react with organic matter naturally present in water, leading to the...Water disinfection is an essential process that provides safe water by inactivating pathogens that cause waterborne diseases. However, disinfectants react with organic matter naturally present in water, leading to the formation of disinfection by-products(DBPs). Multi-analyte methods based on mass spectrometry(MS) are preferred to quantify multiple DBP classes at once however, most require extensive sample pre-treatment and significant resources. In this study, two analytical methods were developed for the quantification of 32 regulated and unregulated DBPs. A purge and trap(P&T) coupled with gas chromatography mass spectrometry(GC-MS) method was optimized that automated sample pre-treatment and analyzed volatile and semi-volatile compounds, including trihalomethanes(THMs), iodinated trihalomethanes(I-THMs), haloacetonitriles(HANs), haloketones(HKTs) and halonitromethanes(HNMs). LOQs were between 0.02-0.4 μg/L for most DBPs except for 8 analytes that were in the low μg/L range. A second method with liquid chromatography(LC) tandem mass spectrometry(MS/MS) was developed for the quantification of 10 haloacetic acids(HAAs) with a simple clean-up and direct injection. The LC-MS/MS direct injection method has the lowest detection limits reported(0.2-0.5 μg/L). Both methods have a simple sample pre-treatment, which make it possible for routine analysis. Hyperchlorination and uniform formation conditions(UFC) formation potential tests with chlorine were evaluated with water samples containing high and low TOC. Hyperchlorination formation potential test maximized THMs and HAAs while UFC maximized HANs. Ascorbic acid was found to be an appropriate quencher for both analytical methods. Disinfected drinking water from four water utilities in Alberta, Canada were also evaluated.展开更多
基金support from the National Natural Science Foundation of China(Grant Nos.:U21A20407 and 81973467).
文摘Prodrugs need to be converted to active drugs to exert their pharmacological activities.Identifying the direct targets of active drugs is essential to elucidate the pharmacological mechanisms of prodrugs,but remains challenging,especially for active drugs with low stability.
基金supported by the Fundamental Research Funds for the Central Universities of China(2572022DQ03)the National Natural Science Foundation of China(32170517)+2 种基金the Guangdong Provincial Key Laboratory of Genome Read and Write(2017B030301011)the Start-up Scientific Foundation of Northeast Forestry University(60201524043)supported by China National GeneBank(CNGB).
文摘Inbreeding increases genome homozygosity within populations,which can exacerbate inbreeding depression by exposing homozygous deleterious alleles that are responsible for declines in fitness traits.In small populations,genetic purging that occurs under the pressure of natural selection acts as an opposing force,contributing to a reduction of deleterious alleles.Both inbreeding and genetic purging are paramount in the field of conservation genomics.The Amur tiger(Panthera tigris altaica)lives in small populations in the forests of Northeast Asia and is among the most endangered animals on the planet.Using genome-wide assessment and comparison,we reveal substantially higher and more extensive inbreeding in wild Amur tigers(F_(ROH)=0.50)than in captive individuals(F_(ROH)=0.24).However,a relatively reduced number of lossof-function mutations in wild Amur tigers is observed compared to captive individuals,indicating genetic purging of inbreeding load with relatively large-effect alleles.The higher ratio of homozygous mutation load and number of fixed damaging alleles in the wild population indicates a less-efficient genetic purging,with purifying selection also contributing to this process.These findings provide valuable insights for the future conservation of Amur tigers.
文摘In photothermal power(solar energy)generation systems,purging residual molten salt from pipelines using highpressure gas poses a significant challenge,particularly in clearing the bottom of regulating valves.Ineffective purging can lead to crystallization of the molten salt,resulting in blockages.To address this issue,understanding the gas-liquid two-phase flow dynamics during high-pressure gas purging is crucial.This study utilizes the Volume of Fluid(VOF)model and adaptive dynamic grids to simulate the gas-liquid two-phase flow during the purging process in a DN50 PN50 conventional molten salt regulating valve.Initially,the reliability of the CFD simulations is validated through comparisons with experimental data and findings from the literature.Subsequently,simulation experiments are conducted to analyze the effects of various factors,including purge flow rates,initial liquid accumulation masses,purge durations,and the profiles of the valve bottom flow channels.The results indicate that the purging process comprises four distinct stages:Initial violent surge stage,liquid discharge stage,liquid partial fallback stage,liquid dissipation stage.For an initial liquid height of 17 mm at the bottom of the valve,the critical purge flow rate lies between 3 and 5 m/s.Notably,the critical purge flow rate is independent of the initial liquid accumulation mass.As the purge gas flow rate increases,the volume of liquid discharged also increases.Beyond the critical purge flow rate,higher purge gas velocities lead to shorter purge durations.Interestingly,the residual liquid mass after purging remains unaffected by the initial liquid accumulation.Additionally,the flow channel profile at the bottom of the valve significantly influences both the critical purge speed and the efficiency of the purging process.
基金the Natural Science Foundation of Jiangsu Province(No.BK20240679)National Natural Science Foundation of China(No.22101134)are greatly acknowledged。
文摘Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operational costs,particularly for hydrocarbons with high boiling points or strong host-vip interactions[2].This is the same case in the newly-developed macrocyclebased crystalline adsorbents,namely nonporous adaptive crystals(NACs).To address these challenges,a recent study published in Angewandte Chemie International Edition by Jie,Ma,and co-workers reported an innovative molecular-"squeeze"triggered desorption mechanism in NACs[3-5].Specifically,ethyl acetate(EA)triggers vip desorption without penetrating the crystal pores or voids.Instead,EA molecules interact with the crystal surface through supramolecular forces,causing the adaptive closure of voids and the subsequent release of vip molecules.Unlike conventional sponges that rely on mechanical squeeze to deform themselves in the bulk for vip release,these macrocycle crystals undergo structural deformation at the molecular level and condensed phase when exposed to vaporized molecules.Because of the similar behavior between sponges and such NACs,the authors name them as sponge-likemacrocyclecrystals.
文摘The pollution of VOCs was studied on both side of highway.With the determination method of purge and trap concentration coupled with gas chromatography-mass spectrometry,we found that the degree of pollution near the highway was not very bad.
文摘Pre-procedural cleansing of the bowel can maximize the effectiveness and efficiency of colonoscopy.Yet,efficacy of the current gold standard colonic preparation method-high-volume oral administration of purgative agents 12-24 h prior to the procedure-is limited by several factors,such as patient compliance(due to poor palatability and inconvenience of the dosing regimen)and risks of complications(due to drug interactions or intolerance).Attempts to resolve these limitations have included providing adjunctive agents and methods to promote the colonic cleansing ability of the principal purgative agent,with the aim of lessening unpleasant side effects(such as bloating)and reducing the large ingested volume requirement.Several promising adjunctive agents are bisacodyl,magnesium citrate,senna,simethicone,metoclopramide,and prokinetics,and each are being investigated for their potential.This review provides an up to date summary of the reported investigations into the potencies and weaknesses of the key adjuncts currently being applied in clinic as supplements to the traditional bowel preparation agents.While the comparative analysis ofthese adjuncts showed that no single agent or method has yet achieved the goal of completely overcoming the limitations of the current gold standard preparation method,they at least provide endoscopists with an array of alternatives to help improve the suboptimal efficacy of the main cleansing solutions when used alone.To aid in this clinical endeavor,a subjective grade was assigned to each adjunct to indicate its practical value.In addition,the systematic review of the currently available agents and methods provides insight into the features of each that may be overcome or exploited to create novel drugs and strategies that may become adopted as effective bowel cleansing adjuncts or alternatives.
文摘AIM:To investigate the changes in renal function at 12-24 mo in patients following sodium phosphate(NaP) preparation for screening colonoscopy.METHODS:We carried out a retrospective study on the results from patients who received health check-up services as part of an employer-provided wellness program performed between August 2006 and May 2008 and who were followed up for 12-24 mo.Prior to screening colonoscopy,224 patients underwent bowel cleansing with NaP(NaP group) and 113 patients with polyethylene glycol(PEG group).The control group comprised 672 age-matched patients.We compared the changes in the creatinine levels and the glomerular filtration rates(GFRs) from baseline to 12-24 mo between the NaP,PEG,and control groups using two-way repeated measured analysis of variance.In addition,multivariate linear regression analysis was performed to assess the risk factors for a decreased GFR.RESULTS:The baseline mean serum creatinine level in the NaP,PEG,and control groups was 1.12 ± 0.15,1.12 ± 0.16,and 1.12 ± 0.15 mg/dL,which increased to 1.15 ± 0.15,1.15 ± 0.18,and 1.15 ± 0.15 mg/dL,respectively,after 12-24 mo.The baseline mean GFR in the NaP,PEG,and control groups was 69.0 ± 7.7,68.9 ± 8.0,and 69.6 ± 6.7 mL/min per 1.73 m2,which decreased to 66.5 ± 7.8,66.5 ± 8.3,and 67.4 ± 6.4 mL/min per 1.73 m2,respectively,after 12-24 mo.The changes in serum creatinine levels and GFRs were not significantly between the NaP,PEG,and control groups(P = 0.992 and P = 0.233,respectively).Using multivariate linear regression analysis,only the baseline GFR was associated with the change in GFR(P < 0.001).Indeed,the bowel preparations were not associated with the change in GFR(P = 0.297).CONCLUSION:NaP bowel preparation in subjects with normal renal function was not associated with renal injury,and NaP can thus be used safely for screening colonoscopy.
文摘AIM To assess the cleansing efficacy and safety of a new Colon capsule endoscopy(CCE)bowel preparation regimen.METHODS This was a multicenter,prospective,randomized,controlled study comparing two CCE regimens.Subjects were asymptomatic and average risk for colorectal cancer.The second generation CCE system(Pill Cam?COLON 2;Medtronic,Yoqneam,Israel)was utilized.Preparation regimens differed in the 1 st and 2 nd boosts with the Study regimen using oral sulfate solution(89 m L)with diatrizoate meglumine and diatrizoate sodium solution("diatrizoate solution")(boost 1=60 m L,boost 2=30 m L)and the Control regimen oral sulfate solution(89 m L)alone.The primary outcome was overall and segmental colon cleansing.Secondary outcomes included safety,polyp detection,colonic transit,CCE completion and capsule excretion≤12 h.RESULTS Both regimens had similar cleansing efficacy for the whole colon(Adequate:Study=75.9%,Control=77.3%;P=0.88)and individual segments.In the Study group,CCE completion was superior(Study=90.9%,Control=76.9%;P=0.048)and colonic transit was more often<40 min(Study=21.8%,Control=4%;P=0.0073).More Study regimen subjects experienced adverse events(Study=19.4%,Control=3.4%;P=0.0061),and this difference did not appear related to diatrizoate solution.Adverse events were primarily gastrointestinal in nature and no serious adverse events related either to the bowel preparation regimen or the capsule were observed.There was a trend toward higher polyp detection with the Study regimen,but this did not achieve statistical significance for any size category.Mean transit time through the entire gastrointestinal tract,from ingestion to excretion,was shorter with the Study regimen while mean colonic transit times were similar for both study groups.CONCLUSION A CCE bowel preparation regimen using oral sulfate solution and diatrizoate solution as a boost agent is effective,safe,and achieved superior CCE completion.
基金supported by the VK’s lab from Savitribai Phule Pune University in the form of Research Grant(No.:OSD/BCUD/392/132)
文摘Rumex nepalensis Spreng.(Polygonaceae) commonly known as Nepal Dock has wide-spectrum therapeutic potencies and is extensively used for centuries in traditional medicine systems. The leaves of this plant are edible and a rich source of natural antioxidants. They act as a possible food supplement and are largely used in pharmaceutical industry. Extracts and metabolites from this plant exhibits pharmacological activities including anti-inflammatory, antioxidant, antibacterial, antifungal, antiviral, insecticidal, purgative, analgesic, antipyretic, anti-algal, central nervous system depressant, genotoxic, wound healing and skeletal muscle relaxant activity. Due to its remarkable biological activities, it has the potential to act as a rich source of drug against life threatening diseases. However, more studies are needed to scientifically validate the traditional uses of this plant, beside isolating and identifying their active principles and characterizing the mechanisms of action. We present herein a critical account of its botany, ecology, traditional uses, phytoconstituent profile and major pharmacological activities reported in recent years and therefore will provide a source of information on this plant for further studies.
基金Supported by the University Board of Research Grant,Ahmadu Bello University,Zaria,Nigeria(Grant No.DAPM/BOD/06)
文摘Objective:To investigate the modulating role of methanol extract of Tephrosia vogelii leaves on acetylcholine(ACh)-induced contraction of isolated rabbit jejunum.Methods: Rabbit jejunum segment was removed and placed in an organ bath containing Tyrode's solution, and its contractions were recorded isometrically.Results: ACh(2.0 × 10-10 g/m L) and the extract(2.0 × 10-4 g/m L) individually increased the frequency of contraction(mean ± SEM) of the isolated smooth muscle tissue by 47.6% ± 9.5% and 77.8% ± 66.5%, respectively. When ACh and the extract were combined, the frequency of contraction of the tissue was increased by 222.2% ± 25.9%, representing a 366.7% increase(P < 0.001) over the effect of ACh alone. Similarly, ACh(2.0 × 10-9 g/m L) and the extract individually increased significantly(P < 0.001) the amplitude of contraction of the tissue by 685.7% ± 61.1% and 455.2% ± 38.1%, respectively. When ACh and the extract were combined, the amplitude of contraction of the tissue rose by 1263.8% ± 69.0%, representing 84.3% increase over the ef ect of ACh alone. Conclusions: The findings demonstrate that methanol extract of Tephrosia vogelii leaves potentiates the contractile ef ect of ACh on intestinal smooth muscle, supporting the traditional claim that the plant is purgative.
基金Key Laboratory Foundation (9140C4103091003C) for funding this work
文摘In modern gas turbines, rim seal located between the stator-disc and rotor-disc is used to prevent hot-gas ingestion into the inner stage-gap of high pressure turbine. However, the purge flow supplied to the cavity through the rim seal interacts with the main flow, producing additional aerodynamic loss due to the mixing process which plays a significant role in the formation, development and evolution of downstream secondary flow. In this paper, a set of cascade representative of low aspect ratio turbine is selected to numerically investigate the influence of upstream cavity purge flow on the hub secondary flow structure and aerodynamic loss. Cascade with/without upstream cavity and four different purge mass flow rates are all taken into account in this simulation. Then, a deep insight into the loss mechanism of interaction between purge flow and main flow is gained. The results show that the presence of cavity and purge flow has a significant impact on the main flow which not only changes the vortex structure in both the passage and upstream cavity, but also alters the cascade exit flow angle distribution along the spanwise. Moreover, aerodynamic loss in the cascade rises with the increase of purge flow rate while the sealing effect is also enhanced. Therefore, the effect of upstream cavity purge flow must be considered in the process of turbine aerodynamic design. What is more, it is necessary to minimize the purge flow rate in order to reduce aerodynamic loss on the premise of satisfying cooling requirements.
基金Supported by the National Natural Science Foundation of China (No.20206030) and Ministry of Science and Technology 863 Hi-Technology Research and Development Program of China (2005AA501660).
文摘At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell (PEMFC) deteriorates markedly. The object of this work is to study the degradation mechanism of key components of PEMFC-membrane-electrode assembly (MEA) and seek feasible measures to avoid degradation. The effect of freeze/thaw cycles on the structure of MEA is investigated based on porosity and SEM measurement. The performance of a single cell was also tested before and after repetitious freeze/thaw cycles. The experimental results indicated that the performance of a PEMFC decreased along with the total operating time as well as the pore size distribution shifting and micro configuration changing. However, when the redundant water had been removed by gas purging, the performance of the PEMFC stack was almost resumed when it experienced again the same subzero temperature test. These results show that it is necessary to remove the water in PEMFCs to maintain stable performance under subzero temperature and gas purging is proved to be the effective operation.
基金supported by the National Natural Science Foundation of China(No.31371826)the China Postdoctoral Science Foundation(No.2016M592002)
文摘Aroma of Chinese steamed bread（CSB） is one of the important parameters that determines the overall quality attributes and consumer acceptance. However, the aroma profile of CSB still remains poorly understood, mainly because of relying on only a single method for aroma extraction in previous studies. Therefore, the objective of this study was to determine the volatile aroma compounds of five different samples of CSB using three different aroma extraction methods, namely solid-phase microextraction（SPME）, simultaneous distillation–extraction（SDE）, and purge and trap（PT）. All samples showed a unique aroma profile, which could be attributed to their unique microbial consortia.（E）-2-Nonenal and（E,E）-2,4-decadienal were the most prevalent aromatic compounds revealed by SDE, which have not been reported previously, while ethanol and acetic acid proved to be the most dominant compounds by both SPME and PT. Our approach of combining three different aroma extraction methods provided better insights into the aroma profile of CSB, which had remained largely unknown in previous studies.
文摘A sequential method for the determination of dimethyl sulfur compounds, including dimethylsulfide （DMS）, dimethylsulfonio- propionate （DMSP） and dimethylsulfoxide （DMSO）, in seawater samples has been developed. Detection limit of 2.5 pmol of DMS in 25 mL sample, corresponding to 0.10 nmol/L, was achieved. Recoveries for dimethyl sulfur compounds were in the range of 68.6- 78.3%. The relative standard deviations （R.S.D.s） for DMS, DMSP and DMSO determination were 3.0, 5.4 and 7.4%, respectively.
基金Funding for this research was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery GrantNSERC for Water Strategic NetworkCanada Foundation for Innovation (CFI)。
文摘Water disinfection is an essential process that provides safe water by inactivating pathogens that cause waterborne diseases. However, disinfectants react with organic matter naturally present in water, leading to the formation of disinfection by-products(DBPs). Multi-analyte methods based on mass spectrometry(MS) are preferred to quantify multiple DBP classes at once however, most require extensive sample pre-treatment and significant resources. In this study, two analytical methods were developed for the quantification of 32 regulated and unregulated DBPs. A purge and trap(P&T) coupled with gas chromatography mass spectrometry(GC-MS) method was optimized that automated sample pre-treatment and analyzed volatile and semi-volatile compounds, including trihalomethanes(THMs), iodinated trihalomethanes(I-THMs), haloacetonitriles(HANs), haloketones(HKTs) and halonitromethanes(HNMs). LOQs were between 0.02-0.4 μg/L for most DBPs except for 8 analytes that were in the low μg/L range. A second method with liquid chromatography(LC) tandem mass spectrometry(MS/MS) was developed for the quantification of 10 haloacetic acids(HAAs) with a simple clean-up and direct injection. The LC-MS/MS direct injection method has the lowest detection limits reported(0.2-0.5 μg/L). Both methods have a simple sample pre-treatment, which make it possible for routine analysis. Hyperchlorination and uniform formation conditions(UFC) formation potential tests with chlorine were evaluated with water samples containing high and low TOC. Hyperchlorination formation potential test maximized THMs and HAAs while UFC maximized HANs. Ascorbic acid was found to be an appropriate quencher for both analytical methods. Disinfected drinking water from four water utilities in Alberta, Canada were also evaluated.
