Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extract...Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extracted from the dog serum using dichlromethane followed by derivatization with DNBF for 20 min at 100℃. The solvent was then evaporated at 60℃ under nitrogen, and the residue was taken up in 100 μL of mobile phase consisting of acetonitrile water (75∶30, v/v). The separation was performed on a Hypersil BDS C18 column with a flow rate of 0 8 mL·min -1 , and the ultraviolet detector wavelength was set at 350 nm. Results Extraction recovery ranged from 75.9% to 83.2%, and methodological recovery was between 96.5% and 109.3%. Within day RSD ranged from 1.5% to 6.3%, and inter day RSD was between 2 9% and 14.8%. The method showed good linearity (R=0.9998). Conclusion The method was simple, convenient and sensitive. The reaction of derivatization was reproducible.展开更多
Based on the authentication tests and the strand space model, the robust email protocol with perfect forward secrecy is formally analyzed, and the security shortcomings of the protocol is pointed out. Meanwhile, the m...Based on the authentication tests and the strand space model, the robust email protocol with perfect forward secrecy is formally analyzed, and the security shortcomings of the protocol is pointed out. Meanwhile, the man-in-the-middle attack to the protocol is given, where the attacker forges the messages in the receiving phase to cheat the two communication parties and makes them share the wrong session keys with him. Therefore, the protocol is not ensured to provide perfect forward secrecy. In order to overcome the above security shortcomings, an advanced email protocol is proposed, where the corresponding signatures in the receiving phase of the protocol are added to overcome the man-in-the-middle attack and ensure to provide perfect forward secrecy. Finally, the proposed advanced email protocol is formally analyzed with the authentication tests and the strand space model, and it is proved to be secure in authentication of the email sender, the recipient and the server. Therefore, the proposed advanced email protocol can really provide perfect forward secrecy.展开更多
According to the security shortages of two robust practical email protocols with perfect forward secrecy, attacks on the two protocols are analyzed and corresponding improvements on the two protocols are proposed. Fir...According to the security shortages of two robust practical email protocols with perfect forward secrecy, attacks on the two protocols are analyzed and corresponding improvements on the two protocols are proposed. First, by analyzing the two email protocols, the corresponding man-in-the-middle attacks are proposed, where the adversary forges the messages in the receiving phase to cheat the two communication participants and makes them share the wrong session keys with him. Consequently, the man-in-the-middle attacks can make the two protocols fail to provide perfect forward secrecy. Secondly, by adding corresponding signatures in the receiving phases of the two protocols, two corresponding improvements on the protocols are proposed to overcome the man-in-the-middle attacks on the two protocols and make them provide perfect forward secrecy. Moreover, the two improved protocols can retain all the merits of the former protocols.展开更多
AIM： To evaluate the effects of indomethacin [dual cyclooxygenase （COX）-I/COX-2 inhibitor] and 3-（3,4-difluorophenyl）-4-（4-（methylsulfonyl） phenyl）- 2-（5H）-furanone （MF-tricyclic） （COX-2 selective inhibi...AIM： To evaluate the effects of indomethacin [dual cyclooxygenase （COX）-I/COX-2 inhibitor] and 3-（3,4-difluorophenyl）-4-（4-（methylsulfonyl） phenyl）- 2-（5H）-furanone （MF-tricyclic） （COX-2 selective inhibi- tor） in a rat experimental model of Barrett＇s esophagus and esophageal adenocarcinoma.METHODS： A total of 112 surviving post-surgery rats were randomly divided into three groups： the control group （n = 48）, which did not receive any treatment; the indomethacin group （n = 32）, which were given 2 mg/kg per day of the COX-I/COX-2 inhibitor; and the MF-tricyclic group （n = 32）, which received 10 mg/kg per day of the selective COX-2 inhibitor. Randomly se- lected rats were killed either 8 wk or 16 wk after sur- gery. The timing of the deaths was in accordance with a previous study performed in our group. Only rats that were killed at the times designated by the protocol were included in the study. We then assessed the histology and prostaglandin E2 （PGE2） expression levels in the rat esophagi. An additional group of eight animals that did not undergo esophagojejunostomy were included in order to obtain normal esophageal tissue as a control. RESULTS： Compared to a control group with no treat- ment （vehicle-treated rats）, indomethacin treatment was associated with decreases in ulcerated esophageal mucosa （16% vs 35% and 14% vs 17%, 2 mo and 4 mo after surgery, respectively; P = 0.021）, length of intestinal metaplasia in continuity with anastomosis （2 4- 1.17 mm vs 2.29 ＋ 0.75 mm and 1.25 4- 0.42 mm vs 3.5 4- 1.54 mm, 2 mo and 4 mo after surgery, respec- tively; P = 0.007）, presence of intestinal metaplasia beyond anastomosis （20% vs 71.4% and 0% vs 60%, 2 mo and 4 mo after surgery, respectively; P = 0.009）, severity of dysplasia （0% vs 71.4% and 20% vs 85.7% high-grade dysplasia, 2 mo and 4 mo after surgery, re- spectively; P = 0.002）, and adenocarcinoma incidence （0% vs 57.1% and 0% vs 60%, 2 mo and 4 mo after surgery, respectively; P 〈 0.0001）. Treatment with the selective COX-2 inhibitor, MF-tricyclic, did not prevent development of intestinal metaplasia or adenocarci- noma. In parallel, we observed a significant decrease in PGE2 levels in indomethacin-treated rats, but not in those treated with MF-tricyclic, at both 2 mo and 4 mo. Compared to control rats that did not undergo surgery （68 ＋ 8 ng/g, P = 0.0022 Kruskal-Wallis test） there was a significant increase in PGE2 levels in the esophageal tissue of the rats that underwent surgery either 2 mo （1332 ＋ 656 ng/g） or 4 mo （1121 ＋ 1015 ng/g） after esophagojejunostomy. However, no differences were found when esophageal PGE2 levels were compared 2 mo vs 4 mo post-esophagojejunostomy. At both the 2- and 4-mo timepoints, we observed a significant decrease in PGE2 levels in indomethacin-treated rat esophagi compared to those in either the control or MF-tricyclic groups （P = 0.049 and P = 0.017, respec- tively）. No differences in PGE2 levels were found when we compared levels in rats treated with MF-tricyclic to not-treated rats. CONCLUSION： In this rat model of gastrointestinal reflux, indomethacin was associated with a decrease in the severity of esophagitis and reduced development of esophageal intestinal metaplasia and adenocarcinoma.展开更多
Aims Global change factors(e.g.warming and nitrogen deposition)may influence biological invasions,but how these factors may influence the performance of invasive species and further mediate the interactions with nativ...Aims Global change factors(e.g.warming and nitrogen deposition)may influence biological invasions,but how these factors may influence the performance of invasive species and further mediate the interactions with native competitors remain still unknown.Methods Here,we conducted a 5-month greenhouse experiment to examine the effects of warming(using open-top chambers,+0.62°C)and N addition(adding NH4NO3 at a rate of 4.2 g m−2)on the performance of the native and invasive populations of an invasive species Plantago virginica in competition with a native Plantago asiatica.Important Findings Under warming treatment and its interaction with nitrogen addition treatment(W×N),invasive and native populations of P.virginica had different biomass allocation strategies to compete with native competitor P.asiatica.Native population of P.virginica(PV-Na)increased more below-ground biomass,whereas those from the invasive population(PV-In)increased more above-ground biomass.We also found that invasive species P.virginica had stronger responses to warming and N addition than the native species P.asiatica.The competitive ability of the invasive plants was significantly reduced by warming which indicated that the invasive plant were much stronger sensitivity to elevated temperature than native plant.Similarly,N addition and W×N reduced the competitive response of PV-In in below-ground biomass,but increased the competitive response of PV-Na in above-ground and total biomass when they grew with the P.asiatica.The results show that P.virginica have occurred differential biomass allocation strategies during its invasions and invasive population exhibit flexible competition ability to adapt to environmental changes(especially warming).These findings may potentially help to predict plant invasions and make management strategies in a world with changing climate.展开更多
Aims Interactions between plants and their soil biota,arbuscular mycorrhizal fungi(AMF)in particular,may play a vital role in the establishment and the range expansion of exotic plants in new environments.However,whet...Aims Interactions between plants and their soil biota,arbuscular mycorrhizal fungi(AMF)in particular,may play a vital role in the establishment and the range expansion of exotic plants in new environments.However,whether there are post-introduction shifts in dependence on AMF and how dependency interacts with competition remains poorly understood.Methods We conducted a common garden greenhouse experiment to examine how native(USA)and invasive(China)populations of the plant species Plantago virginica,respond to soil biota,and whether these responses change in the presence of a competitor.Important Findings We found that while native populations consistently had a higher AMF colonization rate and benefited from AMF in both biomass and seed production,invasive populations received less benefit from AMF,and even showed reduced biomass with AMF in the presence of a competitor.This low mycorrhizal dependency in invasive populations correlated with greater suppression by an indigenous competitor for the invader.The different responses of the invasive and native populations to AMF suggest that alteration of mycorrhizal dependency has occurred during the invasion of P.virginica into China.Our findings suggest that this reduced dependency incurs a cost during interspecific competition.展开更多
文摘Aim A simple, sensitive and rapid RP HPLC method with pre column derivatization has been developed for the determination of sulphonylurea glimepiride in dog serum. Methods The sulphonylurea glimepiride was extracted from the dog serum using dichlromethane followed by derivatization with DNBF for 20 min at 100℃. The solvent was then evaporated at 60℃ under nitrogen, and the residue was taken up in 100 μL of mobile phase consisting of acetonitrile water (75∶30, v/v). The separation was performed on a Hypersil BDS C18 column with a flow rate of 0 8 mL·min -1 , and the ultraviolet detector wavelength was set at 350 nm. Results Extraction recovery ranged from 75.9% to 83.2%, and methodological recovery was between 96.5% and 109.3%. Within day RSD ranged from 1.5% to 6.3%, and inter day RSD was between 2 9% and 14.8%. The method showed good linearity (R=0.9998). Conclusion The method was simple, convenient and sensitive. The reaction of derivatization was reproducible.
基金The Natural Science Foundation of Jiangsu Province(No.BK2006108)
文摘Based on the authentication tests and the strand space model, the robust email protocol with perfect forward secrecy is formally analyzed, and the security shortcomings of the protocol is pointed out. Meanwhile, the man-in-the-middle attack to the protocol is given, where the attacker forges the messages in the receiving phase to cheat the two communication parties and makes them share the wrong session keys with him. Therefore, the protocol is not ensured to provide perfect forward secrecy. In order to overcome the above security shortcomings, an advanced email protocol is proposed, where the corresponding signatures in the receiving phase of the protocol are added to overcome the man-in-the-middle attack and ensure to provide perfect forward secrecy. Finally, the proposed advanced email protocol is formally analyzed with the authentication tests and the strand space model, and it is proved to be secure in authentication of the email sender, the recipient and the server. Therefore, the proposed advanced email protocol can really provide perfect forward secrecy.
基金The Natural Science Foundation of Jiangsu Province(No.BK2006108)
文摘According to the security shortages of two robust practical email protocols with perfect forward secrecy, attacks on the two protocols are analyzed and corresponding improvements on the two protocols are proposed. First, by analyzing the two email protocols, the corresponding man-in-the-middle attacks are proposed, where the adversary forges the messages in the receiving phase to cheat the two communication participants and makes them share the wrong session keys with him. Consequently, the man-in-the-middle attacks can make the two protocols fail to provide perfect forward secrecy. Secondly, by adding corresponding signatures in the receiving phases of the two protocols, two corresponding improvements on the protocols are proposed to overcome the man-in-the-middle attacks on the two protocols and make them provide perfect forward secrecy. Moreover, the two improved protocols can retain all the merits of the former protocols.
基金Supported by Instituto de Salud Carlos III (CIBERehd)MFtricyclic was supplied free of charge by Merck Frosst Canada Inc
文摘AIM： To evaluate the effects of indomethacin [dual cyclooxygenase （COX）-I/COX-2 inhibitor] and 3-（3,4-difluorophenyl）-4-（4-（methylsulfonyl） phenyl）- 2-（5H）-furanone （MF-tricyclic） （COX-2 selective inhibi- tor） in a rat experimental model of Barrett＇s esophagus and esophageal adenocarcinoma.METHODS： A total of 112 surviving post-surgery rats were randomly divided into three groups： the control group （n = 48）, which did not receive any treatment; the indomethacin group （n = 32）, which were given 2 mg/kg per day of the COX-I/COX-2 inhibitor; and the MF-tricyclic group （n = 32）, which received 10 mg/kg per day of the selective COX-2 inhibitor. Randomly se- lected rats were killed either 8 wk or 16 wk after sur- gery. The timing of the deaths was in accordance with a previous study performed in our group. Only rats that were killed at the times designated by the protocol were included in the study. We then assessed the histology and prostaglandin E2 （PGE2） expression levels in the rat esophagi. An additional group of eight animals that did not undergo esophagojejunostomy were included in order to obtain normal esophageal tissue as a control. RESULTS： Compared to a control group with no treat- ment （vehicle-treated rats）, indomethacin treatment was associated with decreases in ulcerated esophageal mucosa （16% vs 35% and 14% vs 17%, 2 mo and 4 mo after surgery, respectively; P = 0.021）, length of intestinal metaplasia in continuity with anastomosis （2 4- 1.17 mm vs 2.29 ＋ 0.75 mm and 1.25 4- 0.42 mm vs 3.5 4- 1.54 mm, 2 mo and 4 mo after surgery, respec- tively; P = 0.007）, presence of intestinal metaplasia beyond anastomosis （20% vs 71.4% and 0% vs 60%, 2 mo and 4 mo after surgery, respectively; P = 0.009）, severity of dysplasia （0% vs 71.4% and 20% vs 85.7% high-grade dysplasia, 2 mo and 4 mo after surgery, re- spectively; P = 0.002）, and adenocarcinoma incidence （0% vs 57.1% and 0% vs 60%, 2 mo and 4 mo after surgery, respectively; P 〈 0.0001）. Treatment with the selective COX-2 inhibitor, MF-tricyclic, did not prevent development of intestinal metaplasia or adenocarci- noma. In parallel, we observed a significant decrease in PGE2 levels in indomethacin-treated rats, but not in those treated with MF-tricyclic, at both 2 mo and 4 mo. Compared to control rats that did not undergo surgery （68 ＋ 8 ng/g, P = 0.0022 Kruskal-Wallis test） there was a significant increase in PGE2 levels in the esophageal tissue of the rats that underwent surgery either 2 mo （1332 ＋ 656 ng/g） or 4 mo （1121 ＋ 1015 ng/g） after esophagojejunostomy. However, no differences were found when esophageal PGE2 levels were compared 2 mo vs 4 mo post-esophagojejunostomy. At both the 2- and 4-mo timepoints, we observed a significant decrease in PGE2 levels in indomethacin-treated rat esophagi compared to those in either the control or MF-tricyclic groups （P = 0.049 and P = 0.017, respec- tively）. No differences in PGE2 levels were found when we compared levels in rats treated with MF-tricyclic to not-treated rats. CONCLUSION： In this rat model of gastrointestinal reflux, indomethacin was associated with a decrease in the severity of esophagitis and reduced development of esophageal intestinal metaplasia and adenocarcinoma.
基金supported by the National Key Research and Development Program of China(no.2017YFC1200105)Project of National Natural Science Foundation of China(no.31100298).
文摘Aims Global change factors(e.g.warming and nitrogen deposition)may influence biological invasions,but how these factors may influence the performance of invasive species and further mediate the interactions with native competitors remain still unknown.Methods Here,we conducted a 5-month greenhouse experiment to examine the effects of warming(using open-top chambers,+0.62°C)and N addition(adding NH4NO3 at a rate of 4.2 g m−2)on the performance of the native and invasive populations of an invasive species Plantago virginica in competition with a native Plantago asiatica.Important Findings Under warming treatment and its interaction with nitrogen addition treatment(W×N),invasive and native populations of P.virginica had different biomass allocation strategies to compete with native competitor P.asiatica.Native population of P.virginica(PV-Na)increased more below-ground biomass,whereas those from the invasive population(PV-In)increased more above-ground biomass.We also found that invasive species P.virginica had stronger responses to warming and N addition than the native species P.asiatica.The competitive ability of the invasive plants was significantly reduced by warming which indicated that the invasive plant were much stronger sensitivity to elevated temperature than native plant.Similarly,N addition and W×N reduced the competitive response of PV-In in below-ground biomass,but increased the competitive response of PV-Na in above-ground and total biomass when they grew with the P.asiatica.The results show that P.virginica have occurred differential biomass allocation strategies during its invasions and invasive population exhibit flexible competition ability to adapt to environmental changes(especially warming).These findings may potentially help to predict plant invasions and make management strategies in a world with changing climate.
基金This work was supported by the Project of NationalNatural Science Foundation of China(31971435)National Key R6DProgram of China(2017YFC1200105).
文摘Aims Interactions between plants and their soil biota,arbuscular mycorrhizal fungi(AMF)in particular,may play a vital role in the establishment and the range expansion of exotic plants in new environments.However,whether there are post-introduction shifts in dependence on AMF and how dependency interacts with competition remains poorly understood.Methods We conducted a common garden greenhouse experiment to examine how native(USA)and invasive(China)populations of the plant species Plantago virginica,respond to soil biota,and whether these responses change in the presence of a competitor.Important Findings We found that while native populations consistently had a higher AMF colonization rate and benefited from AMF in both biomass and seed production,invasive populations received less benefit from AMF,and even showed reduced biomass with AMF in the presence of a competitor.This low mycorrhizal dependency in invasive populations correlated with greater suppression by an indigenous competitor for the invader.The different responses of the invasive and native populations to AMF suggest that alteration of mycorrhizal dependency has occurred during the invasion of P.virginica into China.Our findings suggest that this reduced dependency incurs a cost during interspecific competition.
