A representative nitrogen doped titanium dioxide sample (denoted as N-doped TiO_2) was prepared by treating nanotubular titanic acid (H_2Ti_2O_5·H_2O,NTA in short) in flowing NH_3 at an elevated temperature of 500℃ for 4 h.The sub-band structure within Eg of N-NTA-500 was determined by means of photoluminescence (PL) spectrometry and ultraviolet-visible light-near infrared (UV-Vis-NIR)diffusion reflectance spectrometry (DRS).Moreover,the photocatalytic activity of N-NTA-500 was evaluated by performing the redox reaction of propylene under the irradiation of alternate on-and-off visible light,using commercially available P-25 titania as a comparison.It was found that a large amount of single-electron-trapped oxygen vacancies (denoted as Vo~·) formed a sub-band within the Eg of N-NTA-500,contributing to extend the optical absorption of N-doped TiO_2 into visible light region.The sub-band width,the bottom energy above the top edge of valence band,and the top energy below the bottom edge of conduction band were determined to be 0.24 eV,1.79 eV,and 0.99 eV,respectively.Results and discussion:Each of the four PL spectra at an excitation wavelength of 360-390 nm can be deconvoluted into two bands.The peak positions of the two deconvoluted PL bands for each of the four PL spectra at λ_(ex)=360-390 nm are unchanged and located at 465 nm and 570 nm,respectively,implying that they are not originated from the back band-to-band transition but the e~--h~+recombination on two surface states.The band at 465 nm represents the emission on shallow surface state (2.66 eV above valence band edge),while that band at 570 nm represents the emission on deep surface state (2.17 eV above valence band edge).Moreover,the PL peak intensity decreases with increasing excitation energy,indicating that the photogenerated energy-enriched electrons are firstly relaxed to the bottom of the conduction band and then transferred to the surface state,and the larger the value of E_(ex),the more the energy loss.Therefore,it can be concluded that the excitation at λ_(ex)≤400 nm for N-NTA-500 is dominated by band-to-band transition,while E_g of the N-doped TiO_2 is identical to that of TiO_2 (anatase),I.e.,3.1 eV at 400 nm.The emission mechanism with respect to band-to-band transition of N-NTA-500 in an excitation wavelength range of 360-390 nm is depicted.

Objective To explore how to prevent biliary duct injury during laparoscopic cholecystectomy.Methods The clinical data of 484 cases of laparoscopic cholecystectomy from December 2002 to December 2007 were retrospectively analyzed,and the experiences of preventing biliary duct injury were summarized.Results No biliary duct injury case was found but 26 cases were converted to laparotomy during operation and 20 cases were placed drainage tube.Conclusion Familiar with the anatomy of bile duct,careful handling of the Calot's triangle are the keys to prevent biliary duct injury in LC.

Objective To study the preventive effect of biliary duct injury(BDI)of three-dimensional spiral CT cholangiography(SCTC)before laparoscopic cholecystectomy(LC).Methods A retrospective analysis was carried out for 30 patients suffering from cholelithiasts concurrent with choledocholithiasis from July 2007 to June 2009.EAndoscopic sphincterotomy(EST),then three-dimensional SCTC was carried out through endoscop-ic nasobiliary drainage(ENBD)before IX,and the preventive effect of BDI was evaluated.Results The visibility of intra-hepatic bile duct,the hepatic bile duct and the common bile duct were 100% the visibility of chol-ecyst bile duct was 73% ,and three-dimensional SCTC can tell the position of cholecyst duct,BDI was not happened in all these patients.Conclusion Three-dimensional SCTC before LC can decrease the possibility of BDI.

ObjectiveTo study the preoperative evaluation of three-dimensional spiral CTcholangiography(SCTC) in patients with bile duct obstruction.MethodsA retrospective analysis was performed for 60patients with bile duct obstruction from May 2008 to April 2011,who were treated with endoscopic retrograde cholangiopancreatography( ERCP),then SCTC was performed through endoscopic nasobiliary drainage( EN-BD) tube,and the bile duct tree image of SCTC of bile duct obstruction was evaluated.ResultsIn 60 cases of bile duct obstruction who performed three-dimensional SCTC,the left and right hepatic bile ducts,the hepatic bile duct and the common bile duct were visible in 100％ patients,cholecyst bile duct was visible in 80％ patients,and three-dimensional SCTC can tell the position of cholecyst duct and the place where the cholecyst bile duct enters into the common bile duct.ConclusionThree-dimensional SCTC can show the shape of bile duct tree,especially the cholecyst duct,and has some guidance values in judging the structure of the bile duct tree and the shape of cholecyst bile duct during operation.

Objective To evaluate of three-dimensional spiral CT cholangiography to bile duct configuration before laparoscopic cholecystectomy.Methods A retrospective analysis was performed for 60 patients with cholelithiasts concurrent with choledocholithiasis from May 2009 to April 2012,which were treated with endoscopic retrograde cholangiopancreatography (ERCP),endoscopic sphincterotomy (EST),and endoscopic nasobiliary drainage (ENBD),then three-dimensional spiral CT cholangiography(SCTC) was performed through endoscopic nasobiliary drainage (ENBD) tube,and the bile duct tree image of SCTC was evaluated,then laparoscopic cholecystectomy (LC) was carried out.Results Sixty cases were performed three-dimensional SCTC.The left and right hepatic bile ducts,the hepatic bile duct and the common bile duct were visible in 100％ patients,and cholecyst bile duct was visible in 75％patients,and three-dimensional SCTC can tell the position of cholecyst duct and the place where the cholecyst bile duct enteres into the common bile duct.Conclusion Three-dimensional SCTC can show the shape of bile duct tree,especially the cholecyst duct,and has some guidance values to judge the structure of the bile duct tree and the configuration of cholecyst bile duct during operation,which can decrease the possibility of bile duct injure.

Nanotube titanic acid (NTA) has distinct optical and electrical character, and has photocatalysis character. In accordance with these qualities, NTA was treated with acid so as to enhance its surface activity. Surface structures and surface groups of acid-treated NTA were characterized and analyzed by Transmission Electron Microscope (TEM) and Fourier Transform Infrared Spectrometry (FT-IR). The interaction between acid-treated NTA and amino acids was investigated. Analysis results showed that the lengths of acid-treated NTA became obviously shorter. The diameters of nanotube bundles did not change obviously with acid-treating. Meanwhile, the surface of acid-treated NTA was cross-linked with carboxyl or esterfunction. In addition, acid-treated NTA can catch amino acid residues easily, and then form close combination.
Acetic Acid ; chemistry ; Adsorption ; Amino Acids ; chemistry ; Drug Interactions ; Nanotubes ; chemistry ; Oxides ; chemistry ; Titanium ; chemistry

Pulsatile blood flow plays an important role in maintaining normal vascular endothelial function. Quantitative measurement of pulsatility of artery blood pressure and blood flow in dogs and effects of enhanced external counterpulsation (EECP) on the pulsatility were taken in this study. Common carotid artery blood pressure and blood flow were measured in 6 beagle dogs that had suffered from an acute myocardial infarction 6 weeks before. A 6F tip transducer catheter was inserted into the right common carotid artery to measure blood pressure, and blood flow was measured in the left common carotid artery by an electromagnetic blood flow probe under anesthesia before and during EECP. Blood pulse pressure, pulsatility index (ratio of peak pressure to end diastolic pressure) and standard deviation of blood pressure were calculated to evaluate the pulsatility of arterial blood pressure. Blood pulse flow, pulsatility index (ratio of peak flow to trough flow) and standard deviation of blood flow were calculated to evaluate the pulsatility of blood flow. Mean vascular resistance (MVR) was calculated as MVR = mean blood pressure/mean blood flow. Blood pulse pressure, pulsatility index and standard deviation of blood pressure were elevated from 30 +/- 9 mmHg, 1.26 +/- 0.05 and 8.7 +/- 2.5 mmHg to 43 +/- 8 mmHg (P < 0.05), 1.54 +/- 0.13 and 12.4 +/- 2.0 mmHg (P < 0.05) before and during EECP, respectively. Blood pulse flow, pulsatility index and standard deviation of blood flow were elevated from 317 +/- 48 ml/min, 2.85 +/- 0.21 and 96 +/- 21 ml/min to 447 +/- 88 ml/min, 4.56 +/- 0.90 and 131 +/- 39 ml/min before and during EECP (P < 0.05). MVR was decreased from 578 +/- 72 before EECP to 476 +/- 85 Wood units during EECP(P < 0.05). These data demonstrate that EECP gives an elevation of pulsatility to blood pressure and blood flow, thus it may lead to the decrease of vascular resistance.
Animals ; Blood Pressure ; Carotid Arteries ; physiology ; Counterpulsation ; Dogs ; Hemodynamics ; Pulsatile Flow ; Regional Blood Flow ; Vascular Resistance

Pulsatile blood flow plays an important role in maintaining normal vascular endothelial function. Quantitative measurement of pulsatility of human arterial blood pressure and the influence of enhanced external counterpulsation (EECP) on the pulsatility were investigated in this study. Eight healthy young male volunteers aged 22 to 35 were included. A 4F tip transducer catheter was inserted under local anaesthesia into the radial artery up to the aortic arch. Intraarterial blood pressure was recorded before and during EECP. Blood pulse pressure, pulsatility index (ratio of peak pressure to end diastolic pressure) and standard deviation of blood pressure in 5 cardiac cycle was calculated to evaluate the pulsatility of arterial blood pressure. The results showed that blood pulse pressure, pulsatility index and standard deviation of blood pressure were elevated from 47 +/- 5 mmHg, 1.64 +/- 0.11 and 13.6 +/- 1.5 mmHg to 77 +/- 3 mmHg, 2.46 +/- 0.25 and 19.3 +/- 2.2 mmHg before and during EECP respectively (P < 0.05). Decreasing of systolic pressure and increasing of diastolic pressure during counterpulsation were also observed. EECP gives an elevation of pulsatility to human blood pressure.
Adult ; Blood Pressure ; physiology ; Blood Pressure Determination ; Counterpulsation ; Humans ; Male ; Pulsatile Flow