AIM: To determine the best method out of the three types of interventional procedure for achalasia based on a longterm follow-up.METHODS: The study cohort was comprised of 133 patients of achalasia. Among them, 60 pat...AIM: To determine the best method out of the three types of interventional procedure for achalasia based on a longterm follow-up.METHODS: The study cohort was comprised of 133 patients of achalasia. Among them, 60 patients were treated under fluoroscopy with pneumatic dilation (group A), 8 patients with permanent uncovered or antireflux covered metal stent dilation (group B), and 65 patients with temporary partially covered metal stent dilation (group C).RESULTS: One hundred and thirty dilations were performed on the 60 patients of group A (mean 2.2 times per case).The mean diameter of the strictured cardia was 3.3±2.1 mm before dilation and 10.6±3.8 mm after dilation. The mean dysphagia score was 2.7±1.4 before dilation and 0.9±0.3after dilation. Complications in group A were chest pain (n=30), reflux (n=16), and bleeding (n=6). Thirty-six patients (60 %) in group A exhibited dysphagia relapse during a 12-month follow-up, and 45 patients (90 %) out of 50 exhibited dysphagia relapse during a 36-month followup. Five uncovered and 3 antireflux covered expandable metal stents were permanently placed in the 8 patients of group B. The mean diameter of the strictured cardia was 3.4±1.9 mm before dilation and 19.5±1.1 mm after dilation.The mean dysphagia score was 2.6±1.3 before dilation and 0.4±0.1 after dilation. Complications in group B were chest pain (n=6), reflux (n＝5), bleeding (n=3), and hyperplasia of granulation tissue (n=3). Four patients (50 %) in group B exhibited dysphagia relapse during a 12-month followup, and 2 case (66.7 %) out of 3 patients exhibited dysphagia relapse during a 36-month follow-up. Sixty-five partially covered expandable metal stents were temporarily placed in the 65 patients of group C and withdrawn after 3-7 days via gastroscopy. The mean diameter of the strictured cardia was 3.3±2.3 mm before dilation and 18.9±3.5 mm after dilation. The mean dysphagia score was 2.4±1.3 before dilation and 0.5±0.2 after dilation. Complications in group C were chest pain (n=26), reflux (n展开更多
In the present investigation, influence of gaps between multiple floating structures on wave forces is examined. Strong and complicate hydrodynamic interactions between the floating bodies are observed and the numeric...In the present investigation, influence of gaps between multiple floating structures on wave forces is examined. Strong and complicate hydrodynamic interactions between the floating bodies are observed and the numerical computations have proved the existence of the sharp peak force response on each floating body at some special resonant wave numbers. The resonant wave number is also proved to be around kL=nπ(n=1, 2, …, ∞) with a corresponding frequency shift. A small yet finite gap width will also give influence on the resonant frequency and resonant amplitude of the wave forces, but when the distance between two aligned box-shaped floating bodies becomes big enough, the hydrodynamic interaction can be neglected. The strong hydrodynamic interaction feature has its own important practical significance for the design of module structures and the links (connection) in the whole floating body system. Moreover, the importance is closely related to the hydro-elasticity analyses of a multiple box-shaped floating body system, in which local loads may be as important as the integrated loads.展开更多
Double staining flow cytometry was performed using 7-amino actinomycin D and 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate,to detect the level fluctuation of reactive oxygen species (ROS) during the cel...Double staining flow cytometry was performed using 7-amino actinomycin D and 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate,to detect the level fluctuation of reactive oxygen species (ROS) during the cell cycle of normal NB4 cells. Our results showed that NB4 cells possessed higher level of ROS in G2/M phase than in G1 and S phases. Double staining flow cytometry,with TdT mediated dUTP nick end labeling (Tunel) and propidium iodide (PI),indicated that As2O3 (2 μM) could induce apoptosis in NB4 cells prevailingly from G2/M phase,and this efficacy was enhanced upon co-administration of 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) (2.5 μM) which could produce the endogenous ROS. These results suggested that different ROS level in different cell cycle phases of NB4 cells might determin the selective induction of G2/M apoptosis and the cells' susceptibility to apoptosis by As2O3.展开更多
AIM: To study the therapeutic efficacy of temporary partiallycovered metal stent insertion on benign esophageal stricture.METHODS: Temporary partially-covered metal stent was inserted in 83 patients with benign esopha...AIM: To study the therapeutic efficacy of temporary partiallycovered metal stent insertion on benign esophageal stricture.METHODS: Temporary partially-covered metal stent was inserted in 83 patients with benign esophageal stricture. All the patients had various dysphagia scores.RESULTS: Insertion of 85 temporary partially-covered metal stents was performed successfully in 83 patients with benign esophageal stricture and dysphagia was effectively remitted in all the 83 cases. The dysphagia score was 3.20±0.63(mean±SD) and 0.68±0.31 before and after stent insertion,and 0.86±0.48 after stent removal. The mean diameter of the strictured esophageal lumen was 3.37±1.23 mm and 25.77±3.89 mm before and after stent insertion, and 16.15±2.96 mm after stent removal. Follow-up time was from 1 week to 96 months (mean 54.26±12.75 months). The complications were chest pain (n=37) after stent insertion,and bleeding (n=12) and reflux (n=13) after stent removal.CONCLUSION: Temporary partially-covered metal stent insertion is one of the best methods for treatment of benign esophageal stricture.展开更多
DNA methylation is the most intensively studied epigenetic phenomenon, disturbances of which result in changes ingene transcription, thus exerting drastic imparts onto biological behaviors of cancer. Both the global d...DNA methylation is the most intensively studied epigenetic phenomenon, disturbances of which result in changes ingene transcription, thus exerting drastic imparts onto biological behaviors of cancer. Both the global demethylation andthe local hypermethylation have been widely reported in all types of tumors, providing both challenges and opportunitiesfor a better understanding and eventually controlling of the malignance. However, we are still in the very early stage ofinformation accumulation concerning the tumor associated changes in DNA methylation pattern. A number of excellentrecent reviews have covered this issue in depth. Therefore, this review will summarize our recent data on DNA methy-lation profiling in cancers. Perspectives for the future direction in this dynamic and exciting field will also be given.展开更多
The full-length cDNA of Pinellia ternata agglutinin (PTA) was cloned from inflorescences using RACE-PCR. Through comparative analysis of PTA gene (pta) and its deduced amino acid sequence with those of other Araceae s...The full-length cDNA of Pinellia ternata agglutinin (PTA) was cloned from inflorescences using RACE-PCR. Through comparative analysis of PTA gene (pta) and its deduced amino acid sequence with those of other Araceae species, pta was found to encode a precursor lectin with signal peptide and to have extensive homology with those of other Araceae species. PTA was a heterotetrameric mannose-binding lectin with three mannose-binding boxes like lectins from other Araceae and Amaryllidaceae species. Southern blot analysis of the genomic DNA revealed that pta belonged to a low-copy gene family. Northern blot analysis demonstrated that pta constitutively expressed in various plant tissues including root, leaf, stem and inflorescence. The pta cDNA sequence encoding for mature PTA protein was cloned into pET-32a plasmid and the resulting plasmid, pET-32a-PTA containing Trx-PTA fusion protein, was investigated for the expression in E. coli BL21. SDS-PAGE gel analysis showed that the Trx-PTA fusion protein was successfully expressed in E. coli BL21 when induced by IPTG. Artificial diet assay revealed that PTA fusion protein had significant levels of resistance against peach potato aphids when incorporated into artificial diet at 0.1% (w/v). The cloning of the pta gene will enable us to further test its effect in depth on aphids by transferring the gene into crop plants.展开更多
The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the abso...The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.展开更多
Recently machine learning-based intrusion detection approaches have been subjected to extensive researches because they can detect both misuse and anomaly. In this paper, rough set classification (RSC), a modern learn...Recently machine learning-based intrusion detection approaches have been subjected to extensive researches because they can detect both misuse and anomaly. In this paper, rough set classification (RSC), a modern learning algorithm, is used to rank the features extracted for detecting intrusions and generate intrusion detection models. Feature ranking is a very critical step when building the model. RSC performs feature ranking before generating rules, and converts the feature ranking to minimal hitting set problem addressed by using genetic algorithm (GA). This is done in classical approaches using Support Vector Machine (SVM) by executing many iterations, each of which removes one useless feature. Compared with those methods, our method can avoid many iterations. In addition, a hybrid genetic algorithm is proposed to increase the convergence speed and decrease the training time of RSC. The models generated by RSC take the form of'IF-THEN' rules, which have the advantage of explication. Tests and comparison of RSC with SVM on DARPA benchmark data showed that for Probe and DoS attacks both RSC and SVM yielded highly accurate results (greater than 99% accuracy on testing set).展开更多
Drag reduction characteristics of supercavitating body of revolution was researched numerically with a bubble two-phase flow model embodied in commercial CFD code Fluent 6.0.The work included the effects of body shape...Drag reduction characteristics of supercavitating body of revolution was researched numerically with a bubble two-phase flow model embodied in commercial CFD code Fluent 6.0.The work included the effects of body shape on drag coefficient and supercavity sizes; supercavity control; drag coefficient Cd as a function of cavitation number; and the effect of the ratio of length L to diameter D on drag reduction rate. Research on drag reduction mechanism of supercavitation shows that supercavitation can reduce not only the friction drag coefficient but also the pressure drag coefficient. There may be a best combination among body shape, the ratio L/D, cavitation number, engineering feasibility and so on, which makes the drag reduction ratehighest.展开更多
The dynamics of hydraulic systems are highly nonlinear and the system may be subjected to non-smooth and discontinuous nonlinearities due to directional change of valve opening, friction, etc. Aside from the nonlinear...The dynamics of hydraulic systems are highly nonlinear and the system may be subjected to non-smooth and discontinuous nonlinearities due to directional change of valve opening, friction, etc. Aside from the nonlinear nature of hydraulic dynamics, hydraulic servo systems also have large extent of model uncertainties. To address these challenging issues, a robust state-feedback controller is designed by employing backstepping design technique such that the system output tracks a given signal arbitrarily well, and all signals in the closed-loop system remain bounded. Moreover, a relevant disturbance attenuation inequality is satisfied by the closed-loop signals. Compared with previously proposed robust controllers, this paper's robust controller based on backstepping recursive design method is easier to design, and is more suitable for implementation.展开更多
In this paper the dynamical behaviors of a predator-prey system with Holling Type-Ⅳ functionalresponse are investigated in detail by using the analyses of qualitative method,bifurcation theory,and numericalsimulation...In this paper the dynamical behaviors of a predator-prey system with Holling Type-Ⅳ functionalresponse are investigated in detail by using the analyses of qualitative method,bifurcation theory,and numericalsimulation.The qualitative analyses and numerical simulation for the model indicate that it has a unique stablelimit cycle.The bifurcation analyses of the system exhibit static and dynamical bifurcations including saddle-node bifurcation,Hopf bifurcation,homoclinic bifurcation and bifurcation of cusp-type with codimension two(ie,the Bogdanov-Takens bifurcation),and we show the existence of codimension three degenerated equilibriumand the existence of homoclinic orbit by using numerical simulation.展开更多
AIM:To observe the frequent complications of stent placement for stricture of the gastrointestinal tract and to find proper treatment.METHODS:A total number of 140 stents were inserted in 138 patients with benign stri...AIM:To observe the frequent complications of stent placement for stricture of the gastrointestinal tract and to find proper treatment.METHODS:A total number of 140 stents were inserted in 138 patients with benign stricture of the gastrointestinal tract.The procedure was cornpleted under fluoroscopy in all of the patients.RESULTS:Stents were successfully placed in all the 138 patients.Pains occurred in 23 patients (16.7%),slight or dull pains were found in 21 patients and severe chest pain in 2 respectively.For the former type of pain,the patients receivedonly analgesia or even no treatment,while peridural anesthesics was conducted for the latter condition. Reflux occurred in 16 of these patients (11.6%) after stent placement.It was managed by common antireflux procedures. Gastrointestinal bleeding occurred in 13 patients (9.4%),and was treated by hemostat.Restenosis of the gastrointestinal tract occurred in 8 patients (5.8%),and was apparently associated with hyperplasia of granulation tissue.In 2 patients,the second stent was placed under X-ray guidance.The granulation tissue was removed by cauterization through hot-node therapy under gastroscope guidance in 3 patients,and surgical reconstruction was performed in another 3 patients. Stent migration occurred in 5 patients (3.6%),and were extracted with the aid of a gastroscope.Food-bolus obstruction was encountered in 2 patients (1.4%) and was treated by endoscope removal.No perforation occurred in all patients.CONCLUSION:Frequent complications after stent placement for benign stricture of the gastrointestinal tract include pain,reflux,bleeding,restenosis,stent migration and food-bolus obstruction.They can be treated by drugs,the second stent placement or gastroscopic procedures according to the specific conditions.展开更多
By using variational method of Pekar type, we have studied the energy levels of strong coupling magnetopolaron in disk shape quantum dot(QD) and quantum well(QW). Our results show that, with the increasing magnetic f...By using variational method of Pekar type, we have studied the energy levels of strong coupling magnetopolaron in disk shape quantum dot(QD) and quantum well(QW). Our results show that, with the increasing magnetic field and confinement strength, the magnetopolaron binding energy of QD and QW in the ground state and in the excited state is enhanced. The limiting results of bulk type and strict two dimensional type are obtained.展开更多
Over the past years, more cases using buccal mucosa for urethral reconstruction have been reported.(1-4) The excellent early results with this tissue led some authors to extend their indications for its use. However, ...Over the past years, more cases using buccal mucosa for urethral reconstruction have been reported.(1-4) The excellent early results with this tissue led some authors to extend their indications for its use. However, patients with complex, long-segment urethral strictures and significant scar tissue formation after the failure of previous urethroplasty, still present an operative challenge. The buccal mucosa may not be useful for the treatment of the complicated lengthy urethral strictures because of limited material. To explore the possibility of urethral reconstruction with a graft of colonic mucosa for the treatment of complicated lengthy strictures, we investigated the use of colonic mucosa as a novel substitute for urethral reconstruction in dogs with severe lengthy urethral structure.(5,6) The objects of the present study were to investigate further whether the colonic mucosal graft is an ideal substitute material, for urethral reconstruction, in place of buccal mucosal graft and their pathological characteristic after long-term exposure to urine.展开更多
AIM: To propose a new, non-invasive method for monitoring 24-h pressure, temperature and pH value in gastrointestinal tract.METHODS: The authors developed a miniature, multifunctional gastrointestinal monitoring syste...AIM: To propose a new, non-invasive method for monitoring 24-h pressure, temperature and pH value in gastrointestinal tract.METHODS: The authors developed a miniature, multifunctional gastrointestinal monitoring system, which comprises a set of indigestible biotelemetry capsules and a data recorder.The capsule, after ingested by patients, could measure pressure, temperature and pH value in the gastrointestinal tract and transmit the data to the data recorder outside the body through a 434 MHz radio frequency data link. After the capsule passed out from the body, the data saved in the recorder were downloaded to a workstation via a special software for further analysis and comparison.RESULTS: Clinical experiments showed that the biotelemetry capsules could be swallowed by volunteers without any difficulties. The data recorder could receive the radio frequency signals transmitted by the biotelemetry in the body. The biotelemetry capsule could pass out from the body without difficulties. No discomfort was reported by any volunteer during the experiment. In vivo pressure and temperature data were acquired.CONCLUSION: A non-invasive method for monitoring 24-h gastrointestinal parameters was proposed and tested by the authors. The feasibility and functionality of this method are verified by laboratory tests and clinical experiments.展开更多
AIM: To determine the best mothod for benign stricture of the upper gastrointestinal tract (UGIT) with stent insertion by follow-up evaluation.METHODS: A total of 110 stents insertions were performed in 110 cases of b...AIM: To determine the best mothod for benign stricture of the upper gastrointestinal tract (UGIT) with stent insertion by follow-up evaluation.METHODS: A total of 110 stents insertions were performed in 110 cases of benign stricture of the UGIT. Permanent (group A) and temporary (group B) placement of an expandable metal stent in 30 cases and 80 cases respectively. All cases were completed under fluoroscopy.RESULTS: In group A, 30 uncovered or antireflux covered or partially covered expandable metal stents were placed permanently. In group A, 5 cases (16.7 %) in 3-months, 5 cases (20.0 %) in 6-months, 6 cases (25 %) in the 1st year,6 cases (50 %) in the 3rd year, and 4 cases (80 %) in the 5th year exhibited dysphagia relapse. In group B, a partiallycovered expandable metal stent was temporarily placed in each patient and removed after 3-7 days via gastroscopy.Follow-up data in this group showed that 8 cases (7.5 %) in 3-months, 9 cases (12.0 %) in 6-months, 10 cases (15.4 %) in the 1st year, 6 cases (20 %) in the 3rd year, and 3 cases (25 %) in the 5th year exhibited dysphagia relapse. The placement and withdrawal of all stents were all performed successfully. The follow-up of all cases lasted for 3-99 months (mean 41.6±19.7 months).CONCLUSION: The best mothod for benign stricture of UGIT with stent insertion is temporary placement of a partially-covered expandable metal stent.展开更多
LEACH (Low-Encrgy Adaptive Clustering Hi-erarchy) protocol is a basic clustering-based routing protocol of sensor networks. In this paper, we present the design of SLEACH, asecure extension for the LEACH protocol. We ...LEACH (Low-Encrgy Adaptive Clustering Hi-erarchy) protocol is a basic clustering-based routing protocol of sensor networks. In this paper, we present the design of SLEACH, asecure extension for the LEACH protocol. We divide SLEACH into four phases and fit inexpensivecryplp-graphic operations to each part of the protocol functionality to create an efficient,practical protocol. Then we give security analyses of SLEACH. Our security analyses show that ourschemeis robust against any external attacker or compromised nodes in the sensor network.展开更多
Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size ...Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size and volume fraction of retained austenite, which largely influence the strength and ductility of the steel, are reviewed and discussed one after another. Modelling of the inter-critical annealing and martempering processes as well as the designing of the TRIP steel aided by commercial software are introduced. Some special aspects of the dynamic mechanical properties of TRIP steel are firstly reported.展开更多
AIM: To establish the DNA methylation patterns of the promoter CpG islands of 14 'drug-resistance' genes in hepatocellular carcinoma (HCC).METHODS: The methylation specific polymerase chain reaction in conjunc...AIM: To establish the DNA methylation patterns of the promoter CpG islands of 14 'drug-resistance' genes in hepatocellular carcinoma (HCC).METHODS: The methylation specific polymerase chain reaction in conjunction with sequencing verification was used to establish the methylation patterns of the 14 genes in the liver tissues of four healthy liver donors, as well as tumor and the paired non-cancerous tissues of 30 HCC patients.RESULTS: While 11 genes (ATP-binding cassette, sub-family G (WHITE), member 2(ABCG2), activating transcription factor (ATF2), beta-2-microglobulin (B2M), deoxycytidine kinase(DCK, occludin (OCLN, v-raf-1 murine leukemia viral oncogene homolog (RAF/), ralA binding protein 1 (RALBP1),splicing factor (45 kD) (SPF45), S-phase kinase-associated protein 2 (p45) (SKP2), tumor protein p53 (Li-Fraumeni syndrome) (TP53) and topoisomerase (DNA) II beta (TOP2B) maintained the unmethylated patterns, three genes displayed to various extents the hypermethylation state in tumor tissues in comparison with the normal counterparts. The catalase (CAT) was hypermethylated in tumor and the neighboring non-cancerous tissue of one case (3.3%). Both glutathione S-transferase pi (GSTp/) (80%, 24/30 in tumor and 56.7%,17/30 in the paired non-cancerous tissues) and cystic fibrosis transmembrane conductance regulator, ATP-binding cassette (sub-family C, member 7) (CF-FR) (77%, 23/30 in tumor and 50%, 15/30 in the paired non-cancerous tissues) genes were prevalently hypermethylated in HCC as well as their neighboring non-cancerous tissues. No significant difference in the hypermethylation occurrence was observed between the HCC and its neighboring non-cancerous tissues.CONCLUSION: Hypermethylation of promoter CpG islands of both CF-FR and GSTpigenes occurs prevalently in HCC,which may correlate with the low expression of these two genes at the mRNA level and has the profound etiological and clinical implications. It is likely to be specific to the early phase of HCC carcinogenesis.展开更多
基金the National Key Medical Research and Development Program of China during the 9~(th)Five-year Plan Period(No.96-907-03-04)Shanghai Nature Science Funds(No.02Z1314073)Shanghai Medical Development Funds(No.00419)
文摘AIM: To determine the best method out of the three types of interventional procedure for achalasia based on a longterm follow-up.METHODS: The study cohort was comprised of 133 patients of achalasia. Among them, 60 patients were treated under fluoroscopy with pneumatic dilation (group A), 8 patients with permanent uncovered or antireflux covered metal stent dilation (group B), and 65 patients with temporary partially covered metal stent dilation (group C).RESULTS: One hundred and thirty dilations were performed on the 60 patients of group A (mean 2.2 times per case).The mean diameter of the strictured cardia was 3.3±2.1 mm before dilation and 10.6±3.8 mm after dilation. The mean dysphagia score was 2.7±1.4 before dilation and 0.9±0.3after dilation. Complications in group A were chest pain (n=30), reflux (n=16), and bleeding (n=6). Thirty-six patients (60 %) in group A exhibited dysphagia relapse during a 12-month follow-up, and 45 patients (90 %) out of 50 exhibited dysphagia relapse during a 36-month followup. Five uncovered and 3 antireflux covered expandable metal stents were permanently placed in the 8 patients of group B. The mean diameter of the strictured cardia was 3.4±1.9 mm before dilation and 19.5±1.1 mm after dilation.The mean dysphagia score was 2.6±1.3 before dilation and 0.4±0.1 after dilation. Complications in group B were chest pain (n=6), reflux (n＝5), bleeding (n=3), and hyperplasia of granulation tissue (n=3). Four patients (50 %) in group B exhibited dysphagia relapse during a 12-month followup, and 2 case (66.7 %) out of 3 patients exhibited dysphagia relapse during a 36-month follow-up. Sixty-five partially covered expandable metal stents were temporarily placed in the 65 patients of group C and withdrawn after 3-7 days via gastroscopy. The mean diameter of the strictured cardia was 3.3±2.3 mm before dilation and 18.9±3.5 mm after dilation. The mean dysphagia score was 2.4±1.3 before dilation and 0.5±0.2 after dilation. Complications in group C were chest pain (n=26), reflux (n
文摘In the present investigation, influence of gaps between multiple floating structures on wave forces is examined. Strong and complicate hydrodynamic interactions between the floating bodies are observed and the numerical computations have proved the existence of the sharp peak force response on each floating body at some special resonant wave numbers. The resonant wave number is also proved to be around kL=nπ(n=1, 2, …, ∞) with a corresponding frequency shift. A small yet finite gap width will also give influence on the resonant frequency and resonant amplitude of the wave forces, but when the distance between two aligned box-shaped floating bodies becomes big enough, the hydrodynamic interaction can be neglected. The strong hydrodynamic interaction feature has its own important practical significance for the design of module structures and the links (connection) in the whole floating body system. Moreover, the importance is closely related to the hydro-elasticity analyses of a multiple box-shaped floating body system, in which local loads may be as important as the integrated loads.
基金supported by research grants from National Natural Science Foundation of China(No.30170475)
文摘Double staining flow cytometry was performed using 7-amino actinomycin D and 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate,to detect the level fluctuation of reactive oxygen species (ROS) during the cell cycle of normal NB4 cells. Our results showed that NB4 cells possessed higher level of ROS in G2/M phase than in G1 and S phases. Double staining flow cytometry,with TdT mediated dUTP nick end labeling (Tunel) and propidium iodide (PI),indicated that As2O3 (2 μM) could induce apoptosis in NB4 cells prevailingly from G2/M phase,and this efficacy was enhanced upon co-administration of 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) (2.5 μM) which could produce the endogenous ROS. These results suggested that different ROS level in different cell cycle phases of NB4 cells might determin the selective induction of G2/M apoptosis and the cells' susceptibility to apoptosis by As2O3.
基金the National Key Medical Research and Development Program of China during the 9~(th)Five-year Plan Period(No.96-907-03-04)Shanghai Nature Science Funds(No.02Z 1314073)Shanghai Medical Development Funds(No.00419)
文摘AIM: To study the therapeutic efficacy of temporary partiallycovered metal stent insertion on benign esophageal stricture.METHODS: Temporary partially-covered metal stent was inserted in 83 patients with benign esophageal stricture. All the patients had various dysphagia scores.RESULTS: Insertion of 85 temporary partially-covered metal stents was performed successfully in 83 patients with benign esophageal stricture and dysphagia was effectively remitted in all the 83 cases. The dysphagia score was 3.20±0.63(mean±SD) and 0.68±0.31 before and after stent insertion,and 0.86±0.48 after stent removal. The mean diameter of the strictured esophageal lumen was 3.37±1.23 mm and 25.77±3.89 mm before and after stent insertion, and 16.15±2.96 mm after stent removal. Follow-up time was from 1 week to 96 months (mean 54.26±12.75 months). The complications were chest pain (n=37) after stent insertion,and bleeding (n=12) and reflux (n=13) after stent removal.CONCLUSION: Temporary partially-covered metal stent insertion is one of the best methods for treatment of benign esophageal stricture.
基金The research performed in this lab is supported by Shanghai Science Foundation(NO.04DZ14006)National Natural Science Foundation(NO.30450001)+1 种基金Major State Basic Research Development program of China(NO.2004CB51 8804)the National High Technology Re-search and Development Program of China(NO.2002AA2Z3352).
文摘DNA methylation is the most intensively studied epigenetic phenomenon, disturbances of which result in changes ingene transcription, thus exerting drastic imparts onto biological behaviors of cancer. Both the global demethylation andthe local hypermethylation have been widely reported in all types of tumors, providing both challenges and opportunitiesfor a better understanding and eventually controlling of the malignance. However, we are still in the very early stage ofinformation accumulation concerning the tumor associated changes in DNA methylation pattern. A number of excellentrecent reviews have covered this issue in depth. Therefore, this review will summarize our recent data on DNA methy-lation profiling in cancers. Perspectives for the future direction in this dynamic and exciting field will also be given.
文摘The full-length cDNA of Pinellia ternata agglutinin (PTA) was cloned from inflorescences using RACE-PCR. Through comparative analysis of PTA gene (pta) and its deduced amino acid sequence with those of other Araceae species, pta was found to encode a precursor lectin with signal peptide and to have extensive homology with those of other Araceae species. PTA was a heterotetrameric mannose-binding lectin with three mannose-binding boxes like lectins from other Araceae and Amaryllidaceae species. Southern blot analysis of the genomic DNA revealed that pta belonged to a low-copy gene family. Northern blot analysis demonstrated that pta constitutively expressed in various plant tissues including root, leaf, stem and inflorescence. The pta cDNA sequence encoding for mature PTA protein was cloned into pET-32a plasmid and the resulting plasmid, pET-32a-PTA containing Trx-PTA fusion protein, was investigated for the expression in E. coli BL21. SDS-PAGE gel analysis showed that the Trx-PTA fusion protein was successfully expressed in E. coli BL21 when induced by IPTG. Artificial diet assay revealed that PTA fusion protein had significant levels of resistance against peach potato aphids when incorporated into artificial diet at 0.1% (w/v). The cloning of the pta gene will enable us to further test its effect in depth on aphids by transferring the gene into crop plants.
文摘The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.
文摘Recently machine learning-based intrusion detection approaches have been subjected to extensive researches because they can detect both misuse and anomaly. In this paper, rough set classification (RSC), a modern learning algorithm, is used to rank the features extracted for detecting intrusions and generate intrusion detection models. Feature ranking is a very critical step when building the model. RSC performs feature ranking before generating rules, and converts the feature ranking to minimal hitting set problem addressed by using genetic algorithm (GA). This is done in classical approaches using Support Vector Machine (SVM) by executing many iterations, each of which removes one useless feature. Compared with those methods, our method can avoid many iterations. In addition, a hybrid genetic algorithm is proposed to increase the convergence speed and decrease the training time of RSC. The models generated by RSC take the form of'IF-THEN' rules, which have the advantage of explication. Tests and comparison of RSC with SVM on DARPA benchmark data showed that for Probe and DoS attacks both RSC and SVM yielded highly accurate results (greater than 99% accuracy on testing set).
文摘Drag reduction characteristics of supercavitating body of revolution was researched numerically with a bubble two-phase flow model embodied in commercial CFD code Fluent 6.0.The work included the effects of body shape on drag coefficient and supercavity sizes; supercavity control; drag coefficient Cd as a function of cavitation number; and the effect of the ratio of length L to diameter D on drag reduction rate. Research on drag reduction mechanism of supercavitation shows that supercavitation can reduce not only the friction drag coefficient but also the pressure drag coefficient. There may be a best combination among body shape, the ratio L/D, cavitation number, engineering feasibility and so on, which makes the drag reduction ratehighest.
文摘The dynamics of hydraulic systems are highly nonlinear and the system may be subjected to non-smooth and discontinuous nonlinearities due to directional change of valve opening, friction, etc. Aside from the nonlinear nature of hydraulic dynamics, hydraulic servo systems also have large extent of model uncertainties. To address these challenging issues, a robust state-feedback controller is designed by employing backstepping design technique such that the system output tracks a given signal arbitrarily well, and all signals in the closed-loop system remain bounded. Moreover, a relevant disturbance attenuation inequality is satisfied by the closed-loop signals. Compared with previously proposed robust controllers, this paper's robust controller based on backstepping recursive design method is easier to design, and is more suitable for implementation.
基金Supported by Chinese Academy of Sciences (KZCX2-SW-118)Supported by the NNSF of China (No.10071027No.10231020)
文摘In this paper the dynamical behaviors of a predator-prey system with Holling Type-Ⅳ functionalresponse are investigated in detail by using the analyses of qualitative method,bifurcation theory,and numericalsimulation.The qualitative analyses and numerical simulation for the model indicate that it has a unique stablelimit cycle.The bifurcation analyses of the system exhibit static and dynamical bifurcations including saddle-node bifurcation,Hopf bifurcation,homoclinic bifurcation and bifurcation of cusp-type with codimension two(ie,the Bogdanov-Takens bifurcation),and we show the existence of codimension three degenerated equilibriumand the existence of homoclinic orbit by using numerical simulation.
基金Supported by the National Key Medical Research and DevelopmentProgram of China during the 9~(th) Five-year Plan Period,No.96-907-03-04Shanghai Nature Science Funds,No.02Zl314073Shanghai Medical Development Funds,No.00419
文摘AIM:To observe the frequent complications of stent placement for stricture of the gastrointestinal tract and to find proper treatment.METHODS:A total number of 140 stents were inserted in 138 patients with benign stricture of the gastrointestinal tract.The procedure was cornpleted under fluoroscopy in all of the patients.RESULTS:Stents were successfully placed in all the 138 patients.Pains occurred in 23 patients (16.7%),slight or dull pains were found in 21 patients and severe chest pain in 2 respectively.For the former type of pain,the patients receivedonly analgesia or even no treatment,while peridural anesthesics was conducted for the latter condition. Reflux occurred in 16 of these patients (11.6%) after stent placement.It was managed by common antireflux procedures. Gastrointestinal bleeding occurred in 13 patients (9.4%),and was treated by hemostat.Restenosis of the gastrointestinal tract occurred in 8 patients (5.8%),and was apparently associated with hyperplasia of granulation tissue.In 2 patients,the second stent was placed under X-ray guidance.The granulation tissue was removed by cauterization through hot-node therapy under gastroscope guidance in 3 patients,and surgical reconstruction was performed in another 3 patients. Stent migration occurred in 5 patients (3.6%),and were extracted with the aid of a gastroscope.Food-bolus obstruction was encountered in 2 patients (1.4%) and was treated by endoscope removal.No perforation occurred in all patients.CONCLUSION:Frequent complications after stent placement for benign stricture of the gastrointestinal tract include pain,reflux,bleeding,restenosis,stent migration and food-bolus obstruction.They can be treated by drugs,the second stent placement or gastroscopic procedures according to the specific conditions.
文摘By using variational method of Pekar type, we have studied the energy levels of strong coupling magnetopolaron in disk shape quantum dot(QD) and quantum well(QW). Our results show that, with the increasing magnetic field and confinement strength, the magnetopolaron binding energy of QD and QW in the ground state and in the excited state is enhanced. The limiting results of bulk type and strict two dimensional type are obtained.
文摘Over the past years, more cases using buccal mucosa for urethral reconstruction have been reported.(1-4) The excellent early results with this tissue led some authors to extend their indications for its use. However, patients with complex, long-segment urethral strictures and significant scar tissue formation after the failure of previous urethroplasty, still present an operative challenge. The buccal mucosa may not be useful for the treatment of the complicated lengthy urethral strictures because of limited material. To explore the possibility of urethral reconstruction with a graft of colonic mucosa for the treatment of complicated lengthy strictures, we investigated the use of colonic mucosa as a novel substitute for urethral reconstruction in dogs with severe lengthy urethral structure.(5,6) The objects of the present study were to investigate further whether the colonic mucosal graft is an ideal substitute material, for urethral reconstruction, in place of buccal mucosal graft and their pathological characteristic after long-term exposure to urine.
基金Supported by the National Natural Science Foundation of China, No. 30270382High Technology Research and Development Program of China, No. 2002AA404280
文摘AIM: To propose a new, non-invasive method for monitoring 24-h pressure, temperature and pH value in gastrointestinal tract.METHODS: The authors developed a miniature, multifunctional gastrointestinal monitoring system, which comprises a set of indigestible biotelemetry capsules and a data recorder.The capsule, after ingested by patients, could measure pressure, temperature and pH value in the gastrointestinal tract and transmit the data to the data recorder outside the body through a 434 MHz radio frequency data link. After the capsule passed out from the body, the data saved in the recorder were downloaded to a workstation via a special software for further analysis and comparison.RESULTS: Clinical experiments showed that the biotelemetry capsules could be swallowed by volunteers without any difficulties. The data recorder could receive the radio frequency signals transmitted by the biotelemetry in the body. The biotelemetry capsule could pass out from the body without difficulties. No discomfort was reported by any volunteer during the experiment. In vivo pressure and temperature data were acquired.CONCLUSION: A non-invasive method for monitoring 24-h gastrointestinal parameters was proposed and tested by the authors. The feasibility and functionality of this method are verified by laboratory tests and clinical experiments.
基金National Key Technologies Research and Development Program of China during 9~(th)Five-Year Plan Period,No.96-907-03-04Shanghai Nature Science Funds,No.02Z 1314073Shanghai Medical Development Funds,No.00419
文摘AIM: To determine the best mothod for benign stricture of the upper gastrointestinal tract (UGIT) with stent insertion by follow-up evaluation.METHODS: A total of 110 stents insertions were performed in 110 cases of benign stricture of the UGIT. Permanent (group A) and temporary (group B) placement of an expandable metal stent in 30 cases and 80 cases respectively. All cases were completed under fluoroscopy.RESULTS: In group A, 30 uncovered or antireflux covered or partially covered expandable metal stents were placed permanently. In group A, 5 cases (16.7 %) in 3-months, 5 cases (20.0 %) in 6-months, 6 cases (25 %) in the 1st year,6 cases (50 %) in the 3rd year, and 4 cases (80 %) in the 5th year exhibited dysphagia relapse. In group B, a partiallycovered expandable metal stent was temporarily placed in each patient and removed after 3-7 days via gastroscopy.Follow-up data in this group showed that 8 cases (7.5 %) in 3-months, 9 cases (12.0 %) in 6-months, 10 cases (15.4 %) in the 1st year, 6 cases (20 %) in the 3rd year, and 3 cases (25 %) in the 5th year exhibited dysphagia relapse. The placement and withdrawal of all stents were all performed successfully. The follow-up of all cases lasted for 3-99 months (mean 41.6±19.7 months).CONCLUSION: The best mothod for benign stricture of UGIT with stent insertion is temporary placement of a partially-covered expandable metal stent.
文摘LEACH (Low-Encrgy Adaptive Clustering Hi-erarchy) protocol is a basic clustering-based routing protocol of sensor networks. In this paper, we present the design of SLEACH, asecure extension for the LEACH protocol. We divide SLEACH into four phases and fit inexpensivecryplp-graphic operations to each part of the protocol functionality to create an efficient,practical protocol. Then we give security analyses of SLEACH. Our security analyses show that ourschemeis robust against any external attacker or compromised nodes in the sensor network.
基金supported by the National Natural Science Foundation of China(No.50171038)the Chinese Society for Metals and China-Belgium Bilateral Project(No.2001-242).
文摘Research status of high strength low alloy TRIP (transformation induced plasticity) steels for automobile structural parts is briefly described. Composition and microstruc-ture factors especially the morphology, size and volume fraction of retained austenite, which largely influence the strength and ductility of the steel, are reviewed and discussed one after another. Modelling of the inter-critical annealing and martempering processes as well as the designing of the TRIP steel aided by commercial software are introduced. Some special aspects of the dynamic mechanical properties of TRIP steel are firstly reported.
基金Supported by the National High Technology Research and Development Program of China (863 program),No.2002AA2Z3353 and the Science Foundation of Shanghai Municipal Government,No.02DJ14056
文摘AIM: To establish the DNA methylation patterns of the promoter CpG islands of 14 'drug-resistance' genes in hepatocellular carcinoma (HCC).METHODS: The methylation specific polymerase chain reaction in conjunction with sequencing verification was used to establish the methylation patterns of the 14 genes in the liver tissues of four healthy liver donors, as well as tumor and the paired non-cancerous tissues of 30 HCC patients.RESULTS: While 11 genes (ATP-binding cassette, sub-family G (WHITE), member 2(ABCG2), activating transcription factor (ATF2), beta-2-microglobulin (B2M), deoxycytidine kinase(DCK, occludin (OCLN, v-raf-1 murine leukemia viral oncogene homolog (RAF/), ralA binding protein 1 (RALBP1),splicing factor (45 kD) (SPF45), S-phase kinase-associated protein 2 (p45) (SKP2), tumor protein p53 (Li-Fraumeni syndrome) (TP53) and topoisomerase (DNA) II beta (TOP2B) maintained the unmethylated patterns, three genes displayed to various extents the hypermethylation state in tumor tissues in comparison with the normal counterparts. The catalase (CAT) was hypermethylated in tumor and the neighboring non-cancerous tissue of one case (3.3%). Both glutathione S-transferase pi (GSTp/) (80%, 24/30 in tumor and 56.7%,17/30 in the paired non-cancerous tissues) and cystic fibrosis transmembrane conductance regulator, ATP-binding cassette (sub-family C, member 7) (CF-FR) (77%, 23/30 in tumor and 50%, 15/30 in the paired non-cancerous tissues) genes were prevalently hypermethylated in HCC as well as their neighboring non-cancerous tissues. No significant difference in the hypermethylation occurrence was observed between the HCC and its neighboring non-cancerous tissues.CONCLUSION: Hypermethylation of promoter CpG islands of both CF-FR and GSTpigenes occurs prevalently in HCC,which may correlate with the low expression of these two genes at the mRNA level and has the profound etiological and clinical implications. It is likely to be specific to the early phase of HCC carcinogenesis.
