Mierostruetural development of a commercial 7055 （Al-Zn-Mg-Cu）alloy is studied by transmission electron mieroseope（TEM） during the process of single-ageing for up to 48 h. It is observed that Guinier-Preston （GP...Mierostruetural development of a commercial 7055 （Al-Zn-Mg-Cu）alloy is studied by transmission electron mieroseope（TEM） during the process of single-ageing for up to 48 h. It is observed that Guinier-Preston （GP） zones are formed on { 111} planes when the sample is aged for a short time and grows up gradually with increase of ageing time. η＇ phase is formsed after ageing for 4 h at 120℃, having the orientation relationship with the matrix as[0 0 0 1]η＇//[1 1^- 1]Al and （1 0 1^- 1）η＇//（1 1 0）Al.η phase starts to occur after 24 h ageing and has an orientation relationship with matrix as [1^- 1 0 0]η//[1 1 0]Al and （0 0 0 1）η// （1 1 1）Al. Since the density of both η＇ phase and η phase particles is much lower than that of GP zone on aged alloy, GP zones are important to control the properties of the alloy.展开更多
The self imaging effect in graded index waveguides using annealed proton exchange (APE) technique in lithium niobate (LiNbO 3) waveguides is analyzed and simulated using the three dimensional nonparaxial beam pro...The self imaging effect in graded index waveguides using annealed proton exchange (APE) technique in lithium niobate (LiNbO 3) waveguides is analyzed and simulated using the three dimensional nonparaxial beam propagation method (BPM).On this basis,a 1×8 multimode interference (MMI) optical power splitter by APE technique in X cut LiNibO 3 with Y propagation substrate is fabricated.Measurements show that the device has realized eight powers splittings.展开更多
Based on attenuated total reflection （ATR） and thermo-optic effect, the polymeric thin film planar optical waveguide is used as the temperature sensor, and the factors influencing the sensitivity of the temperature ...Based on attenuated total reflection （ATR） and thermo-optic effect, the polymeric thin film planar optical waveguide is used as the temperature sensor, and the factors influencing the sensitivity of the temperature sensor are comprehensively analyzed. Combined with theoretical analysis and experimental investigation, the sensitivity of the temperature sensor is related to the thicknesses of the upper cladding layer, the waveguide layer, the optical loss of the polymer material and the guided wave modes. The results show that the slope value about reflectivity and temperature, which stands for the sensitivity of the polymer thin film temperature sensor, is associated with the waveguide film thickness and the guided wave modes, and the slope value is the highest in the zero reflectance of a certain transverse electric （TE） mode. To improve the sensitivity of the temperature sensor, the sensor＇s working incident light exterior angle α should be chosen under a certain TE mode with the reflectivity to be zero. This temperature sensor is characterized by high sensitivity and simple structure and it is easily fabricated.展开更多
Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode cont...Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode contacts in FET devices heavily influences the device performance, which makes it difficult to obtain the intrinsic electric properties of nanomaterials. Dielectric force microscopy （DFM）, a contactless method developed recently, can detect the low-frequency dielectric responses of nanomaterials without electric contact, which avoids the influence of electric contact and can be used to study the intrinsic conductivity of nanomaterials. Here we study the influences of surface adsorbates on the conductivity of ZnO nanowires （NWs） by using FET and DFM methods. The conductivity of ZnO NW is much larger in N2 atmosphere than that in ambient environment as measured by FET device, which is further proven by DFM measurement that the ZnO NW exhibits larger dielectric response in N2 environment, and the influence of electrode contacts on measurement can be ruled out. Based on these results, it can be concluded that the adsorbates on ZnO NW surface highly influence the conductivity of ZnO NW rather than the electrode contact. This work also verifies the capability of DFM in measuring electric properties of nanomaterials.展开更多
The leaf structure, content and the storage location of aloin in the leaves of six species of Aloe L. were studied by means of semi-thin section, high performance liquid chromatography (HPLC) and fluorescent microscop...The leaf structure, content and the storage location of aloin in the leaves of six species of Aloe L. were studied by means of semi-thin section, high performance liquid chromatography (HPLC) and fluorescent microscope. Results showed that all leaves consisted of epidermis, chlorenchyma, aquiferous tissue and vascular bundles. The leaves had the xeromorphic characteristics, including thickened epidermal cell wall, thickened cuticle, sunken stomata and well-developed aquiferous tissue. With the exception of thus, there were remarkable differences in leaf structure among the six species. The chlorenchyma cells were similar to palisade tissues in Aloe arborescens Mill. and A. mutabilis Pillans, but isodiametric in A. vera L., A. vera L. var. chinensis Berg., A. saponaria Hawer and A. greenii Bali. A. arborescens, A. mutabilis, A. very and A. vera var. chinensis included large parenchymatous cells at the vascular bundles, whereas no such cells were observed at the vascular bundles of A. saponaria and A. greenii. In A. arborescens, A. mutabilis and A. vera, the aquiferous tissue sheaths were present and composed of a layer of small parenchymatous cells without chloroplasts around the aquiferous tissue. While there were no aquiferous tissue sheaths in A. vera var. chinensis, A. saponaria and A. greenii. The HPLC revealed that the content of aloin was high in A. arborescens, low in A. vera, and very low in A. saponaria among the six species. The fluorescent microscopy showed that the yellow-green globule only appeared in the large parenchymatous cells of vascular bundles, vascular bundle sheath and aquiferous tissue sheath, but not in the chlorenchyma and aquiferous tissue. Consequently, the large parenchymatous cells of vascular bundles, vascular bundle sheath and aquiferous tissue sheath were the storage location of aloin. They were positively correlated with the content of aloin.展开更多
According to the common Glan-Taylor prism's design feature, Fresnel formulae and Brewster's law, a novel Glan -Taylor prism was designed and fabricated. In the new prism, the structure angles of second half we...According to the common Glan-Taylor prism's design feature, Fresnel formulae and Brewster's law, a novel Glan -Taylor prism was designed and fabricated. In the new prism, the structure angles of second half were modified to proper values so that extraordinary ray is incident on with Brewster angle. In order to minimize the deviation angle of the new prism, an additional angle was designed. Theory and experiments have confirmed that the transmittance of the new prism is higher than that of a common one in a wide wavelength range and the interference effect will not occur in the new prism. Experimentally, its deviation angle is smaller than 3′in the wavelength range of 540-670 nm.展开更多
AIM： To investigate the endoscopic hemostasis for gastrointestinal bleeding due to Dieulafoy＇s lesion. METHODS： One hundred and seven patients with gastrointestinal bleeding due to Dieulafoy＇s lesion were treated ...AIM： To investigate the endoscopic hemostasis for gastrointestinal bleeding due to Dieulafoy＇s lesion. METHODS： One hundred and seven patients with gastrointestinal bleeding due to Dieulafoy＇s lesion were treated with three endoscopic hemostasis methods： aethoxysklerol injection （46 cases）, endoscopic hemoclip hemostasis （31 cases）, and a combination of hemoclip hemostasis with aethoxysklerol injection （30 cases）. RESULTS： The rates of successful hemostasis using the three methods were 71.7% （33/46）, 77.4% （24/31） and 96.7% （29/30）, respectively, with significant differences between the methods （P 〈 0.05）. Among those who had unsuccessful treatment with aethoxysklerol injection, 13 were treated with hemoclip hemostasis and 4 underwent surgical operation; 9 cases were successful in the injection therapy. Among the cases with unsuccessful treatment with hemoclip hemostasis,7 were treated with injection of aethoxysklerol and 3 cases underwent surgical operation; 4 cases were successful in the treatment with hemoclip hemostasis. Only 1 case had unsuccessful treatment with a combined therapy of hemoclip hemostasis and aeth- oxysklerol injection, and surgery was then performed. No serious complications of perforation occurred in the patients whose bleeding was treated with the endoscopic hemostasis, and no releeding was found during a 1-year follow-up. CONCLUSION： The combined therapy of hemoclip hemostasis with aethoxysklerol injection is the most effective method for gastrointestinal bleeding due to Dieulafoy＇s lesion.展开更多
AIM:To conduct a meta-analysis to determine the safety and efficacy of laparoscopic liver resection(LLR) and open liver resection(OLR) for hepatocellular carcinoma(HCC).METHODS:PubMed(Medline),EMBASE and Science Citat...AIM:To conduct a meta-analysis to determine the safety and efficacy of laparoscopic liver resection(LLR) and open liver resection(OLR) for hepatocellular carcinoma(HCC).METHODS:PubMed(Medline),EMBASE and Science Citation Index Expanded and Cochrane Central Register of Controlled Trials in the Cochrane Library were searched systematically to identify relevant comparative studies reporting outcomes for both LLR and OLR for HCC between January 1992 and February 2012.Two authors independently assessed the trials for inclusion and extracted the data.Meta-analysis was performed using Review Manager Version 5.0 software(The Cochrane Collaboration,Oxford,United Kingdom).Pooled odds ratios(OR) or weighted mean differences(WMD) with 95%CI were calculated using either fixed effects(Mantel-Haenszel method) or random effects models(DerSimonian and Laird method).Evaluated endpoints were operative outcomes(operation time,intraoperative blood loss,blood transfusion requirement),postoperative outcomes(liver failure,cirrhotic decompensation/ascites,bile leakage,postoperative bleeding,pulmonary complications,intraabdominal abscess,mortality,hospital stay and oncologic outcomes(positive resection margins and tumor recurrence).RESULTS:Fifteen eligible non-randomized studies were identified,out of which,9 high-quality studies involving 550 patients were included,with 234 patients in the LLR group and 316 patients in the OLR group.LLR was associated with significantly lower intraoperative blood loss,based on six studies with 333 patients [WMD:-129.48 mL;95%CI:-224.76-(-34.21) mL;P = 0.008].Seven studies involving 416 patients were included to assess blood transfusion requirement between the two groups.The LLR group had lower blood transfusion requirement(OR:0.49;95%CI:0.26-0.91;P = 0.02).While analyzing hospital stay,six studies with 333 patients were included.Patients in the LLR group were found to have shorter hospital stay [WMD:-3.19 d;95%CI:-4.09-(-2.28) d;P < 0.00001] than their OLR counterpart.Seven studies including 416 patients were pooled together to estimate the odds of developing postoperative ascites in the patient groups.The LLR group appeared to have a lower incidence of postoperative ascites(OR:0.32;95%CI:0.16-0.61;P = 0.0006) as compared with OLR patients.Similarly,fewer patients had liver failure in the LLR group than in the OLR group(OR:0.15;95%CI:0.02-0.95;P =0.04).However,no significant differences were found between the two approaches with regards to operation time [WMD:4.69 min;95%CI:-22.62-32 min;P = 0.74],bile leakage(OR:0.55;95%CI:0.10-3.12;P = 0.50),postoperative bleeding(OR:0.54;95%CI:0.20-1.45;P = 0.22),pulmonary complications(OR:0.43;95%CI:0.18-1.04;P = 0.06),intra-abdominal abscesses(OR:0.21;95%CI:0.01-4.53;P = 0.32),mortality(OR:0.46;95%CI:0.14-1.51;P = 0.20),presence of positive resection margins(OR:0.59;95%CI:0.21-1.62;P = 0.31) and tumor recurrence(OR:0.95;95%CI:0.62-1.46;P = 0.81).CONCLUSION:LLR appears to be a safe and feasible option for resection of HCC in selected patients based on current evidence.However,further appropriately designed randomized controlled trials should be undertaken to ascertain these findings.展开更多
AIM:To evaluate the proportion of successful complete cure en-bloc resections of large colorectal polyps achieved by endoscopic mucosal resection(EMR). METHODS:Studies using the EMR technique to resect large colorecta...AIM:To evaluate the proportion of successful complete cure en-bloc resections of large colorectal polyps achieved by endoscopic mucosal resection(EMR). METHODS:Studies using the EMR technique to resect large colorectal polyps were selected.Successful complete cure en-bloc resection was defined as one piece margin-free polyp resection.Articles were searched for in Medline,Pubmed,and the Cochrane Control Trial Registry,among other sources. RESULTS:An initial search identified 2620 reference articles,from which 429 relevant articles were selected and reviewed.Data was extracted from 25 studies(n =5221)which met the inclusion criteria.All the studies used snares to perform EMR.Pooled proportion of en-bloc resections using a random effect model was 62.85%(95%CI:51.50-73.52).The pooled proportion for complete cure en-bloc resections using a random effect model was 58.66%(95%CI:47.14-69.71).With higher patient load(>200 patients),this complete cure en-bloc resection rate improves from 44.19%(95%CI: 24.31-65.09)to 69.17%(95%CI:51.11-84.61). CONCLUSION:EMR is an effective technique for the resection of large colorectal polyps and offers an alternative to surgery.展开更多
AIM： TO evaluate the effectiveness and safety of capsule endoscopy （CE） in patients with recurrent subacute small bowel obstruction.METHODS： The study was a retrospective analysis of 31 patients referred to hospit...AIM： TO evaluate the effectiveness and safety of capsule endoscopy （CE） in patients with recurrent subacute small bowel obstruction.METHODS： The study was a retrospective analysis of 31 patients referred to hospital from January 2003 to August 2008 for the investigation of subacute small bowel obstruction, who underwent CE. The patients were aged 9-81 years, and all of them had undergone gastroscopy and colonoscopy previously. Some of them received abdominal computed tomography or small bowel follow-through.RESULTS： CE made a definitive diagnosis in 12 （38.7%） of 31 cases： four Crohn＇s disease （CD）, two carcinomas, one intestinal tuberculosis, one ischemic enteritis, one abdominal cocoon, one duplication of the intestine,one diverticulum and one ileal polypoid tumor. Capsule retention occurred in three （9.7%） of 31 patients, and was caused by CD （2） or tumor （1）. Two with retained capsules were retrieved at surgery, and the other one of the capsules was spontaneously passed the stricture by medical treatment in 6 too. No case had an acute small bowel obstruction caused by performance of CE.CONCLUSION： CE provided safe and effective visualization to identify the etiology of a subacute small bowel obstruction, especially in patients with suspected intestinal tumors or CD, which are not identified by routine examinations.展开更多
AIM： To determine the role of ciprofloxacin in reducing cholangitis in cholestatic patients with adequate biliary drainage after endoscopic retrograde cholangiopancreatogra phy （ERCP）. METHODS： A randomized, contr...AIM： To determine the role of ciprofloxacin in reducing cholangitis in cholestatic patients with adequate biliary drainage after endoscopic retrograde cholangiopancreatogra phy （ERCP）. METHODS： A randomized, controlled trial was performed in 48 cholestatic patients at Rajavithi Hospital （Tertiary Referral Center for ERCP： 600 cases per year）. All the 48 patients received 200 mg ciprofloxacin intravenous injection for 30 min before starting any procedures, and then were randomly divided in two groups. Twenty-two patients in study group continually received dprofloxacin until 48 h after ERCP. Causes of biliary obstruction, bacteriology of bile and blood （in cholangitis） and dinical cholangitis were recorded. RESULTS： Forty-eight patients were enrolled and divided into continuous ciprofloxacin treatment group （/7 = 22） and discontinuous ciprofloxacin treatment group （n = 26）. During ERCP, stones were found in 22 patients, malignant diseases in 24 patients and other pathologic lesions in 5 patients. One （4.5%） of the 22 patients who received ciprofloxacin and 2 （6.3%） of the 26 patients who discontinued ciprofloxacin after ERCP developed cholangitis （relative risk = 0.71; 95% CI = 0.14-3.65; P = 0.88）. Bacterobilia was found in 27 （56.3%） out of 48 patients. E. coli and Streptococcus viridans were the most common organisms. CONCLUSION： Continual use of ciprofloxacin in patients with cholestasis after adequate biliary drainage procedures plays no role in reducing cholangitis.展开更多
The influence of vibration is already one of main obstacles for improving the nano measuring accuracy.The techniques of anti-vibration,vibration isolation and vibration compensation become an important branch in nano ...The influence of vibration is already one of main obstacles for improving the nano measuring accuracy.The techniques of anti-vibration,vibration isolation and vibration compensation become an important branch in nano measuring field.Starting with the research of sensitivity to vibration of scanning tunneling microscope(STM),the theory,techniques and realization methods of nano vibration sensor based on tunnel effect are initially investigated,followed by developing the experimental devices.The experiments of the vibration detection and vibration compensation are carried out.The experimental results show that vibration sensor based on tunnel effect is characterized by high sensitivity,good frequency characteristic and the same vibratory response characteristic consistent with STM.展开更多
AIM:To assess the long-term outcome of endoscopic hemorrhoid ligation (EHL) for the treatment of symptomatic internal hemorrhoids.METHODS:A total of 759 consecutive patients (415 males and 344 females) were enrolled.C...AIM:To assess the long-term outcome of endoscopic hemorrhoid ligation (EHL) for the treatment of symptomatic internal hemorrhoids.METHODS:A total of 759 consecutive patients (415 males and 344 females) were enrolled.Clinical presentations were rectal bleeding (593 patients) and mucosal prolapse (166 patients).All patients received EHL at outpatient clinics.Hemorrhoid severity was classified by Goligher's grading.The mean follow-up period was 55.4 mo (range,45-92 mo).RESULTS:The number of band ligations averaged 2.35 in the first session for bleeding and 2.69 for prolapsed patients.Bleeding was controlled in 587 (98.0%) patients,while prolapse was reduced in 137 (82.5%) patients.After treatment,93 patients experienced anal pain and 48 patients had mild bleeding.Patient subjective satisfaction was 93.6%.Repeat treatment or surgery was performed if symptoms were not relieved in the first session.In the bleeding group,the recurrence rate was 3.7% (22 patients) at 1 year,and 6.6%and 13.0% at 2 and 5 years.In the prolapsed group,the recurrence rate was 3.0%,9.6% and 16.9% at 1,2 and 5 years,respectively.CONCLUSION:EHL is an easy and well-tolerated procedure for the treatment of symptomatic internal hemorrhoids,with good long-term results.展开更多
AIM:To examine the prophylactic effect of glyceryl trinitrate on post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis and hyperamylasemia.METHODS:Patients scheduled for ERCP were randomly divided int...AIM:To examine the prophylactic effect of glyceryl trinitrate on post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis and hyperamylasemia.METHODS:Patients scheduled for ERCP were randomly divided into study group and placebo group.Patients in study group and placebo group were treated with 5 mg glyceryl trinitrate and 100 mg vitamin C,respectively,5 min before endoscopic maneuvers.RESULTS:A total of 74 patients were enrolled in the final analysis.Post-ERCP pancreatitis occurred in 3 patients(7.9%) of the study group and 9 patients(25%) in the placebo group(P = 0.012).Hyperamylasemia occurred in 8 patients of the study group(21.1%) and 13 patients(36.1%) of the placebo group(P = 0.037).CONCLUSION:Glyceryl trinitrate before ERCP can effectively prevent post-ERCP and hyperamylasemia.展开更多
AIM:To evaluate the feasibility and safety of laparoscopic distal pancreatectomy(LDP) compared with open distal pancreatectomy(ODP).METHODS:Meta-analysis was performed using the databases,including PubMed,the Cochrane...AIM:To evaluate the feasibility and safety of laparoscopic distal pancreatectomy(LDP) compared with open distal pancreatectomy(ODP).METHODS:Meta-analysis was performed using the databases,including PubMed,the Cochrane Central Register of Controlled Trials,Web of Science and BIOSIS Previews.Articles should contain quantitative data of the comparison of LDP and ODP.Each article was reviewed by two authors.Indices of operative time,spleen-preserving rate,time to fluid intake,ratio of malignant tumors,postoperative hospital stay,incidence rate of pancreatic fistula and overall morbidity rate were analyzed.RESULTS:Nine articles with 1341 patients who underwent pancreatectomy met the inclusion criteria.LDP was performed in 501(37.4%) patients,while ODP was performed in 840(62.6%) patients.There were significant differences in the operative time,time to fluid intake,postoperative hospital stay and spleen-preserving rate between LDP and ODP.There was no difference between the two groups in pancreatic fistula rate [random effects model,risk ratio(RR) 0.996(0.663,1.494),P = 0.983,I2 = 28.4%] and overall morbidity rate [random effects model,RR 0.81(0.596,1.101),P = 0.178,I2 = 55.6%].CONCLUSION:LDP has the advantages of shorter hospital stay and operative time,more rapid recovery and higher spleen-preserving rate as compared with ODP.展开更多
AIM To assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia during peroral endoscopic myotomy(POEM).METHODS Twenty-four patients who underwent POEM and experienced mucosal ...AIM To assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia during peroral endoscopic myotomy(POEM).METHODS Twenty-four patients who underwent POEM and experienced mucosal injury of the cardia during the procedure were retrospectively identified. Of the 24 patients, 21 had mucosal penetration and 3 had only slight mucosal damage without penetration. The 21 patients with mucosal penetration received fibrin sealant for closure at the site of penetration. Penetration-related characteristics, treatment, and recovery were reviewed for all 21 patients to assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia. Clinical data, including general characteristics, procedure-related parameters, Eckardt scores, lower esophageal sphincter pressures (LESP), and esophagogastroduodenoscopy(EGD) results, were analyzed to determine their influence on treatment success after mucosal penetration during POEM.RESULTS All 21 patients had a solitary mucosal penetration in the cardia (12 in esophageal region of the cardia, 9 in the stomach region of the cardia, and 1 in both the esophageal and stomach regions). Twelve had ahole-like penetration and 9 had a linear penetration. For those with a hole-like penetration, the mean size was 0.14 cm2 (0.02-0.32 cm2). For those with a linear penetration, the median size was 0.37 cm (0.10-1.00 cm). Closure of the mucosal penetration using fibrin sealant was performed successfully in all 21 patients(two patients required 5 m L fibrin sealant, and the remaining 19 patients required 2.5 mL). Two patients had a nasogastric tube placed for five days after POEM; the remaining 19 patients were kept fasting for 3 d. All 21 patients were discharged after a median of 5 d(range: 5-7 d) postoperatively. During a median 42 mo (range: 9-62 mo) follow-up, all 21 patients with a mucosal penetration successfully healed without the occurrence of infection, ulcer, or esophagitis. Furthermore, the median LESP decreased from 31.9 mm Hg (range: 21.9-67.1 mm Hg) preoperatively to 20.3 mm Hg (range: 6.0-41.0 mm Hg) postoperatively(P < 0.05). The median preoperative and postoperative Eckardt scores were 5.0(range; 4-10) and 1.0(range: 0-4), respectively (P < 0.05). Of the 21 patients with mucosal penetration, symptom remission, which is defined as a postoperative Eckardt score ≤ 3, was achieved in 20 patients(95.2%) indicating that mucosal penetration did not influence the success of POEM treatment if closed successfully using fibrin sealant.CONCLUSION Fibrin sealant is safe and effective for closure of mucosal penetration during POEM. Mucosal penetrations do not appear to influence the treatment success of POEM if closed successfully using fibrin sealant. Additional studies regarding the feasibility, efficacy, and safety of fibrin sealant for closure of larger mucosal penetrations is warranted.展开更多
AIM:To assess the efficacy of N-acetylcysteine(NAC) and activated Dimethicone in improving endoscopic mucosal visibility.METHODS:A total of 148 patients were randomly allocated into four groups to receive one of the f...AIM:To assess the efficacy of N-acetylcysteine(NAC) and activated Dimethicone in improving endoscopic mucosal visibility.METHODS:A total of 148 patients were randomly allocated into four groups to receive one of the following premedications:group A:100 mL water alone;group B:activated Dimethicone plus water(up to 100 mL);group C:NAC plus water(up to 100 mL);and group D:activated Dimethicone and NAC plus water(up to 100 mL).A single endoscopist blinded to the patients group assessed the gastric mucosal visibility scores(range 1-4) at four sites.The sum of the scores from the four sites was considered as the total mucosal visibility score(TMVS).RESULTS:The patients in group B showed a significantly lower TMVS than those of groups A and C(P < 0.001).The TMVS in patients of group D was significantly lower than that of groups A and C(P < 0.001).The TMVS did not significantly differ between groups B and D(P > 0.05).The difference between TMVS of groups C and A was not significant(P > 0.05).CONCLUSION:Premedication with activated Dimethicone 20 min prior to the upper endoscopy leads to the best visibility.NAC does not improve visualization by itself.展开更多
The effects of pre-aging treatments on subsequent artificial aging response were investigated by means of transmission electron microscopy observations and hardness test in age hardened Al-3.95Cu-(1.32Mg)-0.52Mn-0.11 ...The effects of pre-aging treatments on subsequent artificial aging response were investigated by means of transmission electron microscopy observations and hardness test in age hardened Al-3.95Cu-(1.32Mg)-0.52Mn-0.11 Zr alloys. In Al-3.95Cu-0.52Mn-0.11 Zr alloy, when the pre-aging temperature is 25 °C, the pre-aging treatment has no evident effect on the peak hardness of subsequent artificial aging, while a positive effect(increase of peak hardness) appears when pre-aging temperature is50 °C. However, in Al-3.95Cu-1.32Mg-0.52Mn-0.11 Zr alloy, it is found that whether the pre-aging temperature is 25 °C or 50 °C,the peak artificial aging hardness is lower than that of T6 treated alloy, that is to say, pre-aging treatment has a negative effect on the peak hardness of subsequent artificial aging in the alloys.展开更多
文摘Mierostruetural development of a commercial 7055 （Al-Zn-Mg-Cu）alloy is studied by transmission electron mieroseope（TEM） during the process of single-ageing for up to 48 h. It is observed that Guinier-Preston （GP） zones are formed on { 111} planes when the sample is aged for a short time and grows up gradually with increase of ageing time. η＇ phase is formsed after ageing for 4 h at 120℃, having the orientation relationship with the matrix as[0 0 0 1]η＇//[1 1^- 1]Al and （1 0 1^- 1）η＇//（1 1 0）Al.η phase starts to occur after 24 h ageing and has an orientation relationship with matrix as [1^- 1 0 0]η//[1 1 0]Al and （0 0 0 1）η// （1 1 1）Al. Since the density of both η＇ phase and η phase particles is much lower than that of GP zone on aged alloy, GP zones are important to control the properties of the alloy.
文摘The self imaging effect in graded index waveguides using annealed proton exchange (APE) technique in lithium niobate (LiNbO 3) waveguides is analyzed and simulated using the three dimensional nonparaxial beam propagation method (BPM).On this basis,a 1×8 multimode interference (MMI) optical power splitter by APE technique in X cut LiNibO 3 with Y propagation substrate is fabricated.Measurements show that the device has realized eight powers splittings.
基金The National Natural Science Foundation of China(No.60977038)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20110092110016)+1 种基金the National Basic Research Program of China(973Program)(No.2011CB302004)the Foundation of Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology of Ministry of Education of China(No.201204)
文摘Based on attenuated total reflection （ATR） and thermo-optic effect, the polymeric thin film planar optical waveguide is used as the temperature sensor, and the factors influencing the sensitivity of the temperature sensor are comprehensively analyzed. Combined with theoretical analysis and experimental investigation, the sensitivity of the temperature sensor is related to the thicknesses of the upper cladding layer, the waveguide layer, the optical loss of the polymer material and the guided wave modes. The results show that the slope value about reflectivity and temperature, which stands for the sensitivity of the polymer thin film temperature sensor, is associated with the waveguide film thickness and the guided wave modes, and the slope value is the highest in the zero reflectance of a certain transverse electric （TE） mode. To improve the sensitivity of the temperature sensor, the sensor＇s working incident light exterior angle α should be chosen under a certain TE mode with the reflectivity to be zero. This temperature sensor is characterized by high sensitivity and simple structure and it is easily fabricated.
文摘Characterization of electric properties of nanomaterials usually involves fabricating field effect transistors （FET） and deriving materials properties from device performances. However, the quality of electrode contacts in FET devices heavily influences the device performance, which makes it difficult to obtain the intrinsic electric properties of nanomaterials. Dielectric force microscopy （DFM）, a contactless method developed recently, can detect the low-frequency dielectric responses of nanomaterials without electric contact, which avoids the influence of electric contact and can be used to study the intrinsic conductivity of nanomaterials. Here we study the influences of surface adsorbates on the conductivity of ZnO nanowires （NWs） by using FET and DFM methods. The conductivity of ZnO NW is much larger in N2 atmosphere than that in ambient environment as measured by FET device, which is further proven by DFM measurement that the ZnO NW exhibits larger dielectric response in N2 environment, and the influence of electrode contacts on measurement can be ruled out. Based on these results, it can be concluded that the adsorbates on ZnO NW surface highly influence the conductivity of ZnO NW rather than the electrode contact. This work also verifies the capability of DFM in measuring electric properties of nanomaterials.
文摘The leaf structure, content and the storage location of aloin in the leaves of six species of Aloe L. were studied by means of semi-thin section, high performance liquid chromatography (HPLC) and fluorescent microscope. Results showed that all leaves consisted of epidermis, chlorenchyma, aquiferous tissue and vascular bundles. The leaves had the xeromorphic characteristics, including thickened epidermal cell wall, thickened cuticle, sunken stomata and well-developed aquiferous tissue. With the exception of thus, there were remarkable differences in leaf structure among the six species. The chlorenchyma cells were similar to palisade tissues in Aloe arborescens Mill. and A. mutabilis Pillans, but isodiametric in A. vera L., A. vera L. var. chinensis Berg., A. saponaria Hawer and A. greenii Bali. A. arborescens, A. mutabilis, A. very and A. vera var. chinensis included large parenchymatous cells at the vascular bundles, whereas no such cells were observed at the vascular bundles of A. saponaria and A. greenii. In A. arborescens, A. mutabilis and A. vera, the aquiferous tissue sheaths were present and composed of a layer of small parenchymatous cells without chloroplasts around the aquiferous tissue. While there were no aquiferous tissue sheaths in A. vera var. chinensis, A. saponaria and A. greenii. The HPLC revealed that the content of aloin was high in A. arborescens, low in A. vera, and very low in A. saponaria among the six species. The fluorescent microscopy showed that the yellow-green globule only appeared in the large parenchymatous cells of vascular bundles, vascular bundle sheath and aquiferous tissue sheath, but not in the chlorenchyma and aquiferous tissue. Consequently, the large parenchymatous cells of vascular bundles, vascular bundle sheath and aquiferous tissue sheath were the storage location of aloin. They were positively correlated with the content of aloin.
文摘According to the common Glan-Taylor prism's design feature, Fresnel formulae and Brewster's law, a novel Glan -Taylor prism was designed and fabricated. In the new prism, the structure angles of second half were modified to proper values so that extraordinary ray is incident on with Brewster angle. In order to minimize the deviation angle of the new prism, an additional angle was designed. Theory and experiments have confirmed that the transmittance of the new prism is higher than that of a common one in a wide wavelength range and the interference effect will not occur in the new prism. Experimentally, its deviation angle is smaller than 3′in the wavelength range of 540-670 nm.
基金Supported by Yantai City Science and Technology Development Plan, No. 2010148-13
文摘AIM： To investigate the endoscopic hemostasis for gastrointestinal bleeding due to Dieulafoy＇s lesion. METHODS： One hundred and seven patients with gastrointestinal bleeding due to Dieulafoy＇s lesion were treated with three endoscopic hemostasis methods： aethoxysklerol injection （46 cases）, endoscopic hemoclip hemostasis （31 cases）, and a combination of hemoclip hemostasis with aethoxysklerol injection （30 cases）. RESULTS： The rates of successful hemostasis using the three methods were 71.7% （33/46）, 77.4% （24/31） and 96.7% （29/30）, respectively, with significant differences between the methods （P 〈 0.05）. Among those who had unsuccessful treatment with aethoxysklerol injection, 13 were treated with hemoclip hemostasis and 4 underwent surgical operation; 9 cases were successful in the injection therapy. Among the cases with unsuccessful treatment with hemoclip hemostasis,7 were treated with injection of aethoxysklerol and 3 cases underwent surgical operation; 4 cases were successful in the treatment with hemoclip hemostasis. Only 1 case had unsuccessful treatment with a combined therapy of hemoclip hemostasis and aeth- oxysklerol injection, and surgery was then performed. No serious complications of perforation occurred in the patients whose bleeding was treated with the endoscopic hemostasis, and no releeding was found during a 1-year follow-up. CONCLUSION： The combined therapy of hemoclip hemostasis with aethoxysklerol injection is the most effective method for gastrointestinal bleeding due to Dieulafoy＇s lesion.
文摘AIM:To conduct a meta-analysis to determine the safety and efficacy of laparoscopic liver resection(LLR) and open liver resection(OLR) for hepatocellular carcinoma(HCC).METHODS:PubMed(Medline),EMBASE and Science Citation Index Expanded and Cochrane Central Register of Controlled Trials in the Cochrane Library were searched systematically to identify relevant comparative studies reporting outcomes for both LLR and OLR for HCC between January 1992 and February 2012.Two authors independently assessed the trials for inclusion and extracted the data.Meta-analysis was performed using Review Manager Version 5.0 software(The Cochrane Collaboration,Oxford,United Kingdom).Pooled odds ratios(OR) or weighted mean differences(WMD) with 95%CI were calculated using either fixed effects(Mantel-Haenszel method) or random effects models(DerSimonian and Laird method).Evaluated endpoints were operative outcomes(operation time,intraoperative blood loss,blood transfusion requirement),postoperative outcomes(liver failure,cirrhotic decompensation/ascites,bile leakage,postoperative bleeding,pulmonary complications,intraabdominal abscess,mortality,hospital stay and oncologic outcomes(positive resection margins and tumor recurrence).RESULTS:Fifteen eligible non-randomized studies were identified,out of which,9 high-quality studies involving 550 patients were included,with 234 patients in the LLR group and 316 patients in the OLR group.LLR was associated with significantly lower intraoperative blood loss,based on six studies with 333 patients [WMD:-129.48 mL;95%CI:-224.76-(-34.21) mL;P = 0.008].Seven studies involving 416 patients were included to assess blood transfusion requirement between the two groups.The LLR group had lower blood transfusion requirement(OR:0.49;95%CI:0.26-0.91;P = 0.02).While analyzing hospital stay,six studies with 333 patients were included.Patients in the LLR group were found to have shorter hospital stay [WMD:-3.19 d;95%CI:-4.09-(-2.28) d;P < 0.00001] than their OLR counterpart.Seven studies including 416 patients were pooled together to estimate the odds of developing postoperative ascites in the patient groups.The LLR group appeared to have a lower incidence of postoperative ascites(OR:0.32;95%CI:0.16-0.61;P = 0.0006) as compared with OLR patients.Similarly,fewer patients had liver failure in the LLR group than in the OLR group(OR:0.15;95%CI:0.02-0.95;P =0.04).However,no significant differences were found between the two approaches with regards to operation time [WMD:4.69 min;95%CI:-22.62-32 min;P = 0.74],bile leakage(OR:0.55;95%CI:0.10-3.12;P = 0.50),postoperative bleeding(OR:0.54;95%CI:0.20-1.45;P = 0.22),pulmonary complications(OR:0.43;95%CI:0.18-1.04;P = 0.06),intra-abdominal abscesses(OR:0.21;95%CI:0.01-4.53;P = 0.32),mortality(OR:0.46;95%CI:0.14-1.51;P = 0.20),presence of positive resection margins(OR:0.59;95%CI:0.21-1.62;P = 0.31) and tumor recurrence(OR:0.95;95%CI:0.62-1.46;P = 0.81).CONCLUSION:LLR appears to be a safe and feasible option for resection of HCC in selected patients based on current evidence.However,further appropriately designed randomized controlled trials should be undertaken to ascertain these findings.
文摘AIM:To evaluate the proportion of successful complete cure en-bloc resections of large colorectal polyps achieved by endoscopic mucosal resection(EMR). METHODS:Studies using the EMR technique to resect large colorectal polyps were selected.Successful complete cure en-bloc resection was defined as one piece margin-free polyp resection.Articles were searched for in Medline,Pubmed,and the Cochrane Control Trial Registry,among other sources. RESULTS:An initial search identified 2620 reference articles,from which 429 relevant articles were selected and reviewed.Data was extracted from 25 studies(n =5221)which met the inclusion criteria.All the studies used snares to perform EMR.Pooled proportion of en-bloc resections using a random effect model was 62.85%(95%CI:51.50-73.52).The pooled proportion for complete cure en-bloc resections using a random effect model was 58.66%(95%CI:47.14-69.71).With higher patient load(>200 patients),this complete cure en-bloc resection rate improves from 44.19%(95%CI: 24.31-65.09)to 69.17%(95%CI:51.11-84.61). CONCLUSION:EMR is an effective technique for the resection of large colorectal polyps and offers an alternative to surgery.
文摘AIM： TO evaluate the effectiveness and safety of capsule endoscopy （CE） in patients with recurrent subacute small bowel obstruction.METHODS： The study was a retrospective analysis of 31 patients referred to hospital from January 2003 to August 2008 for the investigation of subacute small bowel obstruction, who underwent CE. The patients were aged 9-81 years, and all of them had undergone gastroscopy and colonoscopy previously. Some of them received abdominal computed tomography or small bowel follow-through.RESULTS： CE made a definitive diagnosis in 12 （38.7%） of 31 cases： four Crohn＇s disease （CD）, two carcinomas, one intestinal tuberculosis, one ischemic enteritis, one abdominal cocoon, one duplication of the intestine,one diverticulum and one ileal polypoid tumor. Capsule retention occurred in three （9.7%） of 31 patients, and was caused by CD （2） or tumor （1）. Two with retained capsules were retrieved at surgery, and the other one of the capsules was spontaneously passed the stricture by medical treatment in 6 too. No case had an acute small bowel obstruction caused by performance of CE.CONCLUSION： CE provided safe and effective visualization to identify the etiology of a subacute small bowel obstruction, especially in patients with suspected intestinal tumors or CD, which are not identified by routine examinations.
文摘AIM： To determine the role of ciprofloxacin in reducing cholangitis in cholestatic patients with adequate biliary drainage after endoscopic retrograde cholangiopancreatogra phy （ERCP）. METHODS： A randomized, controlled trial was performed in 48 cholestatic patients at Rajavithi Hospital （Tertiary Referral Center for ERCP： 600 cases per year）. All the 48 patients received 200 mg ciprofloxacin intravenous injection for 30 min before starting any procedures, and then were randomly divided in two groups. Twenty-two patients in study group continually received dprofloxacin until 48 h after ERCP. Causes of biliary obstruction, bacteriology of bile and blood （in cholangitis） and dinical cholangitis were recorded. RESULTS： Forty-eight patients were enrolled and divided into continuous ciprofloxacin treatment group （/7 = 22） and discontinuous ciprofloxacin treatment group （n = 26）. During ERCP, stones were found in 22 patients, malignant diseases in 24 patients and other pathologic lesions in 5 patients. One （4.5%） of the 22 patients who received ciprofloxacin and 2 （6.3%） of the 26 patients who discontinued ciprofloxacin after ERCP developed cholangitis （relative risk = 0.71; 95% CI = 0.14-3.65; P = 0.88）. Bacterobilia was found in 27 （56.3%） out of 48 patients. E. coli and Streptococcus viridans were the most common organisms. CONCLUSION： Continual use of ciprofloxacin in patients with cholestasis after adequate biliary drainage procedures plays no role in reducing cholangitis.
文摘The influence of vibration is already one of main obstacles for improving the nano measuring accuracy.The techniques of anti-vibration,vibration isolation and vibration compensation become an important branch in nano measuring field.Starting with the research of sensitivity to vibration of scanning tunneling microscope(STM),the theory,techniques and realization methods of nano vibration sensor based on tunnel effect are initially investigated,followed by developing the experimental devices.The experiments of the vibration detection and vibration compensation are carried out.The experimental results show that vibration sensor based on tunnel effect is characterized by high sensitivity,good frequency characteristic and the same vibratory response characteristic consistent with STM.
文摘AIM:To assess the long-term outcome of endoscopic hemorrhoid ligation (EHL) for the treatment of symptomatic internal hemorrhoids.METHODS:A total of 759 consecutive patients (415 males and 344 females) were enrolled.Clinical presentations were rectal bleeding (593 patients) and mucosal prolapse (166 patients).All patients received EHL at outpatient clinics.Hemorrhoid severity was classified by Goligher's grading.The mean follow-up period was 55.4 mo (range,45-92 mo).RESULTS:The number of band ligations averaged 2.35 in the first session for bleeding and 2.69 for prolapsed patients.Bleeding was controlled in 587 (98.0%) patients,while prolapse was reduced in 137 (82.5%) patients.After treatment,93 patients experienced anal pain and 48 patients had mild bleeding.Patient subjective satisfaction was 93.6%.Repeat treatment or surgery was performed if symptoms were not relieved in the first session.In the bleeding group,the recurrence rate was 3.7% (22 patients) at 1 year,and 6.6%and 13.0% at 2 and 5 years.In the prolapsed group,the recurrence rate was 3.0%,9.6% and 16.9% at 1,2 and 5 years,respectively.CONCLUSION:EHL is an easy and well-tolerated procedure for the treatment of symptomatic internal hemorrhoids,with good long-term results.
文摘AIM:To examine the prophylactic effect of glyceryl trinitrate on post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis and hyperamylasemia.METHODS:Patients scheduled for ERCP were randomly divided into study group and placebo group.Patients in study group and placebo group were treated with 5 mg glyceryl trinitrate and 100 mg vitamin C,respectively,5 min before endoscopic maneuvers.RESULTS:A total of 74 patients were enrolled in the final analysis.Post-ERCP pancreatitis occurred in 3 patients(7.9%) of the study group and 9 patients(25%) in the placebo group(P = 0.012).Hyperamylasemia occurred in 8 patients of the study group(21.1%) and 13 patients(36.1%) of the placebo group(P = 0.037).CONCLUSION:Glyceryl trinitrate before ERCP can effectively prevent post-ERCP and hyperamylasemia.
基金Supported by The key project grant from the Science and Technology Department of Zhejiang Province,No.2011C13036-2
文摘AIM:To evaluate the feasibility and safety of laparoscopic distal pancreatectomy(LDP) compared with open distal pancreatectomy(ODP).METHODS:Meta-analysis was performed using the databases,including PubMed,the Cochrane Central Register of Controlled Trials,Web of Science and BIOSIS Previews.Articles should contain quantitative data of the comparison of LDP and ODP.Each article was reviewed by two authors.Indices of operative time,spleen-preserving rate,time to fluid intake,ratio of malignant tumors,postoperative hospital stay,incidence rate of pancreatic fistula and overall morbidity rate were analyzed.RESULTS:Nine articles with 1341 patients who underwent pancreatectomy met the inclusion criteria.LDP was performed in 501(37.4%) patients,while ODP was performed in 840(62.6%) patients.There were significant differences in the operative time,time to fluid intake,postoperative hospital stay and spleen-preserving rate between LDP and ODP.There was no difference between the two groups in pancreatic fistula rate [random effects model,risk ratio(RR) 0.996(0.663,1.494),P = 0.983,I2 = 28.4%] and overall morbidity rate [random effects model,RR 0.81(0.596,1.101),P = 0.178,I2 = 55.6%].CONCLUSION:LDP has the advantages of shorter hospital stay and operative time,more rapid recovery and higher spleen-preserving rate as compared with ODP.
文摘AIM To assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia during peroral endoscopic myotomy(POEM).METHODS Twenty-four patients who underwent POEM and experienced mucosal injury of the cardia during the procedure were retrospectively identified. Of the 24 patients, 21 had mucosal penetration and 3 had only slight mucosal damage without penetration. The 21 patients with mucosal penetration received fibrin sealant for closure at the site of penetration. Penetration-related characteristics, treatment, and recovery were reviewed for all 21 patients to assess the efficacy and safety of fibrin sealant for closure of mucosal penetration at the cardia. Clinical data, including general characteristics, procedure-related parameters, Eckardt scores, lower esophageal sphincter pressures (LESP), and esophagogastroduodenoscopy(EGD) results, were analyzed to determine their influence on treatment success after mucosal penetration during POEM.RESULTS All 21 patients had a solitary mucosal penetration in the cardia (12 in esophageal region of the cardia, 9 in the stomach region of the cardia, and 1 in both the esophageal and stomach regions). Twelve had ahole-like penetration and 9 had a linear penetration. For those with a hole-like penetration, the mean size was 0.14 cm2 (0.02-0.32 cm2). For those with a linear penetration, the median size was 0.37 cm (0.10-1.00 cm). Closure of the mucosal penetration using fibrin sealant was performed successfully in all 21 patients(two patients required 5 m L fibrin sealant, and the remaining 19 patients required 2.5 mL). Two patients had a nasogastric tube placed for five days after POEM; the remaining 19 patients were kept fasting for 3 d. All 21 patients were discharged after a median of 5 d(range: 5-7 d) postoperatively. During a median 42 mo (range: 9-62 mo) follow-up, all 21 patients with a mucosal penetration successfully healed without the occurrence of infection, ulcer, or esophagitis. Furthermore, the median LESP decreased from 31.9 mm Hg (range: 21.9-67.1 mm Hg) preoperatively to 20.3 mm Hg (range: 6.0-41.0 mm Hg) postoperatively(P < 0.05). The median preoperative and postoperative Eckardt scores were 5.0(range; 4-10) and 1.0(range: 0-4), respectively (P < 0.05). Of the 21 patients with mucosal penetration, symptom remission, which is defined as a postoperative Eckardt score ≤ 3, was achieved in 20 patients(95.2%) indicating that mucosal penetration did not influence the success of POEM treatment if closed successfully using fibrin sealant.CONCLUSION Fibrin sealant is safe and effective for closure of mucosal penetration during POEM. Mucosal penetrations do not appear to influence the treatment success of POEM if closed successfully using fibrin sealant. Additional studies regarding the feasibility, efficacy, and safety of fibrin sealant for closure of larger mucosal penetrations is warranted.
文摘AIM:To assess the efficacy of N-acetylcysteine(NAC) and activated Dimethicone in improving endoscopic mucosal visibility.METHODS:A total of 148 patients were randomly allocated into four groups to receive one of the following premedications:group A:100 mL water alone;group B:activated Dimethicone plus water(up to 100 mL);group C:NAC plus water(up to 100 mL);and group D:activated Dimethicone and NAC plus water(up to 100 mL).A single endoscopist blinded to the patients group assessed the gastric mucosal visibility scores(range 1-4) at four sites.The sum of the scores from the four sites was considered as the total mucosal visibility score(TMVS).RESULTS:The patients in group B showed a significantly lower TMVS than those of groups A and C(P < 0.001).The TMVS in patients of group D was significantly lower than that of groups A and C(P < 0.001).The TMVS did not significantly differ between groups B and D(P > 0.05).The difference between TMVS of groups C and A was not significant(P > 0.05).CONCLUSION:Premedication with activated Dimethicone 20 min prior to the upper endoscopy leads to the best visibility.NAC does not improve visualization by itself.
基金Project(2006AA03Z517)supported by the National High-tech Research and Development Program of ChinaProject(CSUZC2013019)supported by Open Fund for the Precision Instruments of Central South University,China
文摘The effects of pre-aging treatments on subsequent artificial aging response were investigated by means of transmission electron microscopy observations and hardness test in age hardened Al-3.95Cu-(1.32Mg)-0.52Mn-0.11 Zr alloys. In Al-3.95Cu-0.52Mn-0.11 Zr alloy, when the pre-aging temperature is 25 °C, the pre-aging treatment has no evident effect on the peak hardness of subsequent artificial aging, while a positive effect(increase of peak hardness) appears when pre-aging temperature is50 °C. However, in Al-3.95Cu-1.32Mg-0.52Mn-0.11 Zr alloy, it is found that whether the pre-aging temperature is 25 °C or 50 °C,the peak artificial aging hardness is lower than that of T6 treated alloy, that is to say, pre-aging treatment has a negative effect on the peak hardness of subsequent artificial aging in the alloys.
