Search

Background A computer-assisted (CAD) system was developed to assess, score, and classify the technical difficulty of common bile duct (CBD) stone removal during endoscopic retrograde cholangiopancreatography (ERCP). The efficacy of the CAD system was subsequently assessed through a multicenter, prospective, observational study. Method All patients who met the inclusion criteria were included. Based on cholangiogram images, the CAD system analyzed the level of difficulty of stone removal and classified it into “difficult” and “easy” groups. Subsequently, differences in clinical endpoints, including attempts at stone extraction, stone extraction time, total operation time, and stone clearance rates were compared between the two groups. Results 173 patients with CBD stones from three hospitals were included in the study. The group classified as difficult by CAD had more extraction attempts (7.20 vs. 4.20, P Conclusion The CAD system effectively assessed and classified the degree of technical difficulty in endoscopic stone extraction during ERCP. In addition, it automatically provided a quantitative evaluation of CBD and stones, which in turn could help endoscopists to apply suitable procedures and interventional methods to minimize the possible risks associated with endoscopic stone removal.

Accurate endoscopic optical prediction of the depth of cancer invasion is critical for guiding an optimal treatment approach of large sessile colorectal polyps but was hindered by insufficient endoscopists expertise and inter-observer variability. We aimed to construct a clinically applicable AI system for the identification of presence of cancer invasion in large sessile colorectal polyps.A deep learning based colorectal cancer invasion calculation (CCIC) system was constructed. Multi-modal data including clinical information, white light (WL) and image enhanced endoscopy (IEE) were included for training. The system was trained using 339 lesions and tested on 198 lesions across 3 hospitals. Man-machine contest, reader study and video validation were further conducted to evaluate the performance of CCIC.The overall accuracy of CCIC system using image and video validation was 90.4% and 89.7%, respectively. In comparison with 14 endoscopists, the accuracy of CCIC was comparable with expert endoscopists but superior to all the participating senior and junior endoscopists in both image and video validation set. With CCIC augmentation, the average accuracy of junior endoscopists improved significantly from 75.4% to 85.3% (P=0.002).This deep learning based CCIC system may play an important role in predicting the depth of cancer invasion in colorectal polyps, thus determining treatment strategies for these large sessile colorectal polyps.

Mulching has been extensively sought after in modern agriculture. However, massive utilization of plastics for mulching has induced severe environmental concerns. Developing biodegradable mulch thus represents an emerging need for future agriculture. By using bamboo-derived carboxymethyl cellulose (CMC), this study proposed a crosslinking strategy to prepare liquid film as quality mulch. CMC was synthesized by delignifying bamboo and etherifying resultant cellulose, which was then blended with polyvinyl alcohol (PVA) and crosslinked by glutaraldehyde to prepare a liquid film. By simply spraying on soil, mulch can quickly form on soil surface. Especially, bamboo-timber derived mulch had strong mechanical property (18.2 MPa), good transmittance (74.2%) and moisture absorption (141%), and excellent soil moisture retention. More importantly, about 64% of used mulches were biodegraded within 60-d after burring in soil, which will not need post-handling. These results highlighted that bamboo-derived mulch can be an alternative of current plastic mulch to tackle associated environmental pollution.

Background Tandem colonoscopy studies have found that about one in five adenomas are missed at colonoscopy. It remains debatable whether the combination of a computer-aided polyp detection (CADe) system with a computer-aided quality improvement (CAQ) system for real-time monitoring of withdrawal speed results in additional benefits in adenoma detection or if the synergetic effect may be harmed due to excessive visual burden resulting from information overload. This study aimed to evaluate the interaction effect on improving the adenoma detection rate (ADR). Methods This single-center, randomized, four-group, parallel, controlled study was performed at Renmin Hospital of Wuhan University. Between 1 July and 15 October 2020, 1076 patients were randomly allocated into four treatment groups: control 271, CADe 268, CAQ 269, and CADe plus CAQ (COMBO) 268. The primary outcome was ADR. Results The ADR in the control, CADe, CAQ, and COMBO groups was 14.76 % (95 % confidence interval [CI] 10.54 to 18.98), 21.27 % (95 %CI 16.37 to 26.17), 24.54 % (95 %CI 19.39 to 29.68), and 30.60 % (95 %CI 25.08 to 36.11), respectively. The ADR was higher in the COMBO group compared with the CADe group (21.27 % vs. 30.6 %, P = 0.024, odds ratio [OR] 1.284, 95 %CI 1.033 to 1.596) but not compared with the CAQ group (24.54 % vs. 30.6 %, P = 0.213, OR 1.309, 95 %CI 0.857 to 2.000, respectively). Conclusions CAQ significantly improved the efficacy of CADe in a four-group, parallel, controlled study. No significant difference in the ADR or polyp detection rate was found between CAQ and COMBO.

Recently, the study of quantum materials through thermal characterization methods has attracted much attention. These methods, although not as widely used as electrical methods, can reveal intriguing physical properties in materials that are not detectable by electrical methods, particularly in electrical insulators. A fundamental understanding of these physical properties is critical for the development of novel applications for energy conversion and storage, quantum sensing and quantum information processing. In this review, we introduce several commonly used thermal characterization methods for quantum materials, including specific heat, thermal conductivity, thermal Hall effect, and Nernst effect measurements. Important theories for the thermal properties of quantum materials are discussed. Moreover, we introduce recent research progress on thermal measurements of quantum materials. We highlight experimental studies on probing the existence of quantum spin liquids, Berry curvature, chiral anomaly, and coupling between heat carriers. We also discuss the work on investigating the quantum phase transitions and quasi-particle hydrodynamics using thermal characterization methods. These findings have significantly advanced knowledge regarding novel physical properties in quantum materials. In addition, we provide some perspectives on further investigation of novel thermal properties in quantum materials.

Extracting roads from aerial images is a challenging task in the field of remote sensing. Most approaches formulate road extraction as a segmentation problem and use thinning and edge detection to obtain road centerlines and edge lines, which could produce spurs around the extracted centerlines/edge lines. In this study, a novel regression-based method is proposed to extract road centerlines and edge lines directly from aerial images. The method consists of three major steps. First, an end-to-end regression network based on CNN is trained to predict confidence maps for road centerlines and estimate road width. Then, after the CNN predicts the confidence map, non-maximum suppression and road tracking are applied to extract accurate road centerlines and construct road topology. Meanwhile, Road edge lines are generated based on the road width estimated by the CNN. Finally, in order to improve the connectivity of extracted road network, tensor voting is applied to detect road intersections and the detected intersections are used as guidance for the overcome of discontinuities. The experiments conducted on the SpaceNet and DeepGlobe datasets show that our approach achieves better performance than other methods.

Summary Background Colonoscopy performance varies among endoscopists, impairing the discovery of colorectal cancers and precursor lesions. We aimed to construct a real-time quality improvement system (ENDOANGEL) to monitor real-time withdrawal speed and colonoscopy withdrawal time and to remind endoscopists of blind spots caused by endoscope slipping. We also aimed to evaluate the effectiveness of this system for improving adenoma yield of everyday colonoscopy. Methods The ENDOANGEL system was developed using deep neural networks and perceptual hash algorithms. We recruited consecutive patients aged 18–75 years from Renmin Hospital of Wuhan University in China who provided written informed consent. We randomly assigned patients (1:1) using computer-generated random numbers and block randomisation (block size of four) to either colonoscopy with the ENDOANGEL system or unassisted colonoscopy (control). Endoscopists were not masked to the random assignment but analysts and patients were unaware of random assignments. The primary endpoint was the adenoma detection rate (ADR), which is the proportion of patients having one or more adenomas detected at colonoscopy. The primary analysis was done per protocol (ie, in all patients having colonoscopy done in accordance with the assigned intervention) and by intention to treat (ie, in all randomised patients). This trial is registered with http://www.chictr.org.cn , ChiCTR1900021984. Findings Between June 18, 2019, and Sept 6, 2019, 704 patients were randomly allocated colonoscopy with the ENDOANGEL system (n=355) or unassisted (control) colonoscopy (n=349). In the intention-to-treat population, ADR was significantly greater in the ENDOANGEL group than in the control group, with 58 (16%) of 355 patients allocated ENDOANGEL-assisted colonoscopy having one or more adenomas detected, compared with 27 (8%) of 349 allocated control colonoscopy (odds ratio [OR] 2·30, 95% CI 1·40–3·77; p=0·0010). In the per-protocol analysis, findings were similar, with 54 (17%) of 324 patients assigned ENDOANGEL-assisted colonoscopy and 26 (8%) of 318 patients assigned control colonoscopy having one or more adenomas detected (OR 2·18, 95% CI 1·31–3·62; p=0·0026). No adverse events were reported. Interpretation The ENDOANGEL system significantly improved the adenoma yield during colonoscopy and seems to be effective and safe for use during routine colonoscopy. Funding Hubei Provincial Clinical Research Center for Digestive Disease Minimally Invasive Incision, Hubei Province Major Science and Technology Innovation Project, and the National Natural Science Foundation of China.

— Sapium sebiferum is one of the four woody oil tree species in China for bioenergy forest. Its seeds have high oil content and are widely used. It is an excellent tree species that can be cultivated as a renewable energy source. An experiment was conducted to study culture in vitro and rapid propagation of S. sebiferum using segments with axillary bud. The results showed that the survival rate could be reached to 50.0% when the explants were disinfected with 70% ethanol for 30 seconds and with 0.1% HgCl2 for 10 minutes. In induction culture, the lateral buds began to sprout about 5 days later, and after 20 days, the buds gradually differentiated. Among the three basic mediums, WPM medium has the highest effective bud induction rate, the effect of 6-benzyladenine (6-BA) mass concentration on axillary bud induction rate is extremely significant. The optimal medium WPM +6-BA 0.5mg/L+ NAA 0.05mg/L, conducting bud induction, and the induction rate could reach 62.9% after 30 days. Multiplication culture was carried out in the medium MS + 6-BA 1.0 mg/L +NAA 0.5 mg/L+ KT 0.5 mg/L, the proliferation effect was the best, with the multiplication rate of 81.2% and proliferation multiple of 3.2. The results of variance analysis showed that Naphthalene acetic acid (NAA) is the main factor affecting bud proliferation, followed by 6-BA. The rooting rate was up to 93.3% after induction in the medium 1/2 MS+ IBA 0.5mg/L. The establishmentofrapid propagation technology system through tissue culture is animportantwaytosolve the shortage of high-quality seedlings and provide technical support for the establishment of large scale S. sebiferum energy forest.

Boron arsenide (BAs) is an ultrahigh-thermal-conductivity material with special phonon-phonon scattering behaviors. At ambient pressure, the bunching of acoustic phonon branches in BAs is believed to result in a small phase space for three-phonon scattering. Density functional theory predicts that this acoustic phonon bunching effect is sensitive to pressure and leads to an unusual pressure dependence of thermal conductivity. To explore this physics, we measure the thermal conductivity of BAs from 0 to 25 GPa using time-domain thermoreflectance in a diamond anvil cell. We characterized two BAs samples with ambient thermal conductivities of 350 and 480 W m-1 K-1. Our experiments show that the thermal conductivity of both samples depends weakly on pressure from 0 to 25 GPa. We attribute the weak pressure dependence of the thermal conductivity of BAs to the weak pressure dependence of total phonon-phonon scattering rates. Our experimental results are consistent with DFT predictions that three-phonon scattering rates increase from 0 to 25 GPa, while four-phonon scattering rates decrease.

The optical diagnosis of colorectal cancer (CRC) invasion depth with white light (WL) and image-enhanced endoscopy (IEE) remains challenging. We aimed to construct and validate a 2-modal deep learning-based system, incorporated with both WL and IEE images (named Endo-CRC) in estimating the invasion depth of CRC.Samples were retrospectively obtained from 3 hospitals in China. We combined WL and IEE images into image pairs. Altogether, 337,278 image pairs from 268 noninvasive and superficial CRC and 181,934 image pairs from 82 deep CRC were used for training. A total of 296,644 and 4528 image pairs were used for internal and external tests and for comparison with endoscopists. Thirty-five videos were used for evaluating the real-time performance of the Endo-CRC system. Two deep learning models, solely using either WL (model W) or IEE images (model I), were constructed to compare with Endo-CRC.The accuracies of Endo-CRC in internal image tests with and without advanced CRC were 91.61% and 93.78%, respectively, and 88.65% in the external test, which did not include advanced CRC. In an endoscopist-machine competition, Endo-CRC achieved an expert comparable accuracy of 88.11% and the highest sensitivity compared with all endoscopists. In a video test, Endo-CRC achieved an accuracy of 100.00%. Compared with model W and model I, Endo-CRC had a higher accuracy (per image pair: 91.61% vs 88.27% compared with model I and 91.61% vs 81.32% compared with model W).The Endo-CRC system has great potential for assisting in CRC invasion depth diagnosis and may be well applied in clinical practice.

Computed tomography (CT) is the preferred imaging method for diagnosing 2019 novel coronavirus (COVID19) pneumonia. We aimed to construct a system based on deep learning for detecting COVID-19 pneumonia on high resolution CT. For model development and validation, 46,096 anonymous images from 106 admitted patients, including 51 patients of laboratory confirmed COVID-19 pneumonia and 55 control patients of other diseases in Renmin Hospital of Wuhan University were retrospectively collected. Twenty-seven prospective consecutive patients in Renmin Hospital of Wuhan University were collected to evaluate the efficiency of radiologists against 2019-CoV pneumonia with that of the model. An external test was conducted in Qianjiang Central Hospital to estimate the system’s robustness. The model achieved a per-patient accuracy of 95.24% and a per-image accuracy of 98.85% in internal retrospective dataset. For 27 internal prospective patients, the system achieved a comparable performance to that of expert radiologist. In external dataset, it achieved an accuracy of 96%. With the assistance of the model, the reading time of radiologists was greatly decreased by 65%. The deep learning model showed a comparable performance with expert radiologist, and greatly improved the efficiency of radiologists in clinical practice.

Background Accurate identification of the differentiation status and margins for early gastric cancer (EGC) is critical for determining the surgical strategy and achieving curative resection in EGC patients. The aim of this study was to develop a real-time system to accurately identify differentiation status and delineate the margins of EGC on magnifying narrow-band imaging (ME-NBI) endoscopy. Methods 2217 images from 145 EGC patients and 1870 images from 139 EGC patients were retrospectively collected to train and test the first convolutional neural network (CNN1) to identify EGC differentiation status. The performance of CNN1 was then compared with that of experts using 882 images from 58 EGC patients. Finally, 928 images from 132 EGC patients and 742 images from 87 EGC patients were used to train and test CNN2 to delineate the EGC margins. Results The system correctly predicted the differentiation status of EGCs with an accuracy of 83.3 % (95 % confidence interval [CI] 81.5 % – 84.9 %) in the testing dataset. In the man – machine contest, CNN1 performed significantly better than the five experts (86.2 %, 95 %CI 75.1 % – 92.8 % vs. 69.7 %, 95 %CI 64.1 % – 74.7 %). For delineating EGC margins, the system achieved an accuracy of 82.7 % (95 %CI 78.6 % – 86.1 %) in differentiated EGC and 88.1 % (95 %CI 84.2 % – 91.1 %) in undifferentiated EGC under an overlap ratio of 0.80. In unprocessed EGC videos, the system achieved real-time diagnosis of EGC differentiation status and EGC margin delineation in ME-NBI endoscopy. Conclusion We developed a deep learning-based system to accurately identify differentiation status and delineate the margins of EGC in ME-NBI endoscopy. This system achieved superior performance when compared with experts and was successfully tested in real EGC videos.

BackgroundComputed tomography (CT) is the preferred imaging method for diagnosing 2019 novel coronavirus (COVID19) pneumonia. Our research aimed to construct a system based on deep learning for detecting COVID-19 pneumonia on high resolution CT, relieve working pressure of radiologists and contribute to the control of the epidemic.MethodsFor model development and validation, 46,096 anonymous images from 106 admitted patients, including 51 patients of laboratory confirmed COVID-19 pneumonia and 55 control patients of other diseases in Renmin Hospital of Wuhan University (Wuhan, Hubei province, China) were retrospectively collected and processed. Twenty-seven consecutive patients undergoing CT scans in Feb, 5, 2020 in Renmin Hospital of Wuhan University were prospectively collected to evaluate and compare the efficiency of radiologists against 2019-CoV pneumonia with that of the model.FindingsThe model achieved a per-patient sensitivity of 100%, specificity of 93.55%, accuracy of 95.24%, PPV of 84.62%, and NPV of 100%; a per-image sensitivity of 94.34%, specificity of 99.16%, accuracy of 98.85%, PPV of 88.37%, and NPV of 99.61% in retrospective dataset. For 27 prospective patients, the model achieved a comparable performance to that of expert radiologist. With the assistance of the model, the reading time of radiologists was greatly decreased by 65%.ConclusionThe deep learning model showed a comparable performance with expert radiologist, and greatly improve the efficiency of radiologists in clinical practice. It holds great potential to relieve the pressure of frontline radiologists, improve early diagnosis, isolation and treatment, and thus contribute to the control of the epidemic.

Poor oral health appears to be a risk factor for pancreatic cancer, possibly implicating the oral microbiota. In this pilot study, we evaluated the characteristics of the oral microbiota in patients with pancreatic ductal adenocarcinoma (PDAC), intraductal papillary mucinous neoplasms (IPMN), and healthy controls. Forty newly diagnosed PDAC patients, 39 IPMN patients, and 58 controls, excluding current smokers and users of antibiotics, provided saliva samples. Common oral bacterial species were comprehensively surveyed by sequencing of the 16S rRNA microbial genes. We obtained measures of diversity and the mean relative proportions of individual taxa. We explored the degree to which these measures differed according to respondent characteristics based on individual interviews. PDAC cases did not differ in diversity measures from either controls or IPMN cases. PDAC cases had higher mean relative proportions of Firmicutes and related taxa, while controls had higher mean relative proportions of Proteobacteria and related taxa. Results were generally similar when comparing PDAC to IPMN cases. Among IPMNs and controls combined, younger individuals had higher levels of several taxa within the Proteobacteria. The only other variable consistently related to mean relative proportions was mouthwash use, with taxa within Firmicutes more common among users. While there were no differences in diversity of the oral microbiota among these groups, there were differences in the mean relative proportions of some taxa. Characteristics of the oral microbiota are not associated with most measures of oral health.

We aimed to determine the severity and co-occurrence of established and potential paraneoplastic conditions in pancreatic cancer (weight loss, new onset diabetes, fatigue, and depression) and their relation to patient characteristics.Using information from personal interviews with 510 cases and 463 controls, we obtained adjusted odds ratios for weight loss, long-term and new-onset diabetes, fatigue, and depression before diagnosis. Among cases, we investigated the extent to which these factors occurred together and the characteristics of those reporting them.The adjusted odds ratio for weight loss (3% of usual weight) was 27.0 (95% confidence interval, 17.1-42.6). Severe weight loss was common (21% of cases lost15%), and was more common in those previously obese. Diabetes was more common in cases and was strongly associated with weight loss (P0.0001). Diabetes in cases more often led to prescription of insulin, compared with controls.Fatigue and depression were significantly more common in cases than controls but not related to weight loss or diabetes. These conditions were not related to stage at diagnosis.Weight loss, often severe, and new-onset diabetes frequently occur together before diagnosis of pancreatic cancer. Fatigue and depression are also potential precursors of diagnosis.

A new composite adsorbent, zeolite-supported microscale zero-valent iron (Z-mZVI) was evaluated as a potential adsorbent for the removal of Cd

Optical branch waveguides are one of the most important optical elements and have been widely exploited for optical communication systems. However, prevailing devices are typically solid and have limit in tunability. Liquid optical devices have attracted more interest for the advantage of tunability of liquid media, but their signals suffer serious leakage if the refractive index (RI) of liquid is smaller than that of solid channels. This paper demonstrates the tunable three-dimensional (3D) optofluidic Y-branch waveguides in plannar microchannels by simply introducing Dean flow. This device can reconfigure 3D Y-branch profiles and separate the intensity of light as tunable ratio from 0 to 1 by adjusting the flow rates with low loss. Different from the prevailing 2D liquid counterparts, the 3D configuration offer much more freedom in the selection of liquid media as liquid’s RI can be totally independent to the solid channel structure. The transmission loss through the device is estimated to 0.97 db when the splitting angle is 10°, which shows the light is confined better in the 3D liquid structures than traditional 2D liquid counterparts. The Y-branch waveguides show potential in applications of integrated optofluidic devices.

Objective To report our experience and assess the safety and efficacy of Doppler ultrasound–guided percutaneous nephrolithotomy (PCNL) with 2-step tract dilation for complex renal stones. Materials and Methods From March 2009 to February 2011, 262 patients underwent PCNL. Eighty-three patients had a complete and 105 had partial staghorn calculus, and 74 had a renal pelvic stone of >2 cm in diameter. Thirty-five patients had renal surgical history. Doppler ultrasound–guided PCNL with 2-step tract dilation were performed. Stones were fragmented and cleared using a combination of ultrasonic and pneumatic lithotripters. Results All PCNL procedures were successful. Successful access to the collecting system was 100%. Although most of the cases (231/262) were managed satisfactorily by a single tract, a second tract was used in 31 cases. Mean operation time was 56 minutes (range 25–145). The primary stone-free rate of PCNL was 80.9%. There were 39 auxiliary procedures (13 second PCNL and 26 extracorporeal shock wave lithotripsy). One month after treatment, the overall stone-free rate was 92.7%. Five patients (1.9%) received blood transfusion. Eight patients (3.1%) with a postoperative fever of ≥38.5°C were cured by intravenous antibiotics. No other severe complications occurred. The mean postoperative stay was 3.8 days (range 2–12). Conclusion Doppler ultrasound–guided PCNL with 2-step tract dilation for complex renal stones is safe, effective, and worthy of wider use in clinical practice.

For the purpose of utilizing bamboo cellulose and providing a theoretical basis, the isothermal crystallization kinetics of modified bamboo cellulose/poly(e-caprolactone) (MBC/PCL) composites has been investigated by differential scanning calorimetry (DSC) at different crystallization temperature (Tc). The Avrami model was applied to describe the process of isothermal crystallization. According to Hoffman–Weeks theory, the values of the equilibrium melting point ( T m 0 ) increased with an increase in the content of MBC in the composites. The spherulite growth rate, the overall crystallization rate, the activation energy and folding-surface free energy (σe) of PCL/MBC composites are markedly affected by the presence of MBC. According to Avrami theory, MBC accelerates the crystallization of PCL in the composites. However, as compared to neat PCL, all the composites of PCL/MBC had the higher σe value. This indicates that there exist constraints on the mobility of the PCL chains in the interspherulitic regions due to the presence of MBC.

To report our experience and assess the feasibility and safety of laparoendoscopic single-site (LESS) retroperitoneoscopic nephrectomy for giant hydronephrosis.Between July 2011 and April 2013, 22 patients underwent LESS retroperitoneoscopic nephrectomy for giant hydronephrosis with nonfunctioning kidneys. A reusable elastic single-port device was inserted through the 2.5-cm incision at the midpoint between the costal arch and iliac crest on the midaxillary line. A rigid, 10-mm, 30° extra-long laparoscope was introduced for monitoring, and a combination of lengthened prebent and conventional laparoscopic instruments was used for handling. The operation procedure was similar to the conventional retroperitoneal laparoscopic nephrectomy.LESS retroperitoneoscopic nephrectomy was completed in all patients without conversion to open surgery and the additional placement of ports. The mean operative time was 98 minutes (range 77-146), and estimated blood loss was 45 mL (range 20-120). No major intraoperative complications occurred. The postoperative period was uneventful in all patients and the mean hospital stay was 3.4 days (range 2-7).LESS retroperitoneoscopic nephrectomy for giant hydronephrosis is technically feasible and safe for selected patients. The combination of conventional and prebent laparoscopic instruments represents an attractive option for retroperitoneoscopic LESS.

Heavy oil residua contain large amounts of hetero-atoms, such as sulfur, nitrogen, oxygen and metals. The metals, mainly vanadium and nickel, are removed by catalytic hydrotreatment. Sulfur, nitrogen and oxygen containing compounds present in heavy oil residua can influence the rate at which the metals are removed, since they can adsorb competitively on the active site of the catalyst. Hence, the rate of the hydrogenation and ring cleavage steps in the hydrodemetallisation of the organo-metallic compounds may be slowed down. In the present work the competitive effect of hetero-atom containing compounds which are analogues of those occurring in heavy oil residua, i.e. quinoline, ammonia, benzofuran, water, dibenzothiophene and anthracene, has been investigated on the hydrodemetallisation of vanadyl-tetraphenyl-porphyrin. The spiked amount of hetero-atoms has been chosen near to those occurring in oil residua. The added hetero-atom containing compounds appeared to decrease the rate of metal removal. An increasing effect on the hydrogenation steps was found in the following sequence: dibenzothiophene < quinoline < anthracene ≈ benzofuran < ammonia ≈ water. For the lumped ring cleavage step the effect increased in the following sequence: dibenzothiophene < anthracene ≈ quinoline ≈ benzofuran < ammonia < water. The effect of quinoline, benzofuran, dibenzothiophene and anthracene is caused by competitive adsorption on the active sites of the catalyst. Water and ammonia, which have the most pronounced effect, are suggested to be co-ordinated to the vanadyl group in the porphyrin and, therefore, decrease the rate of metal removal. It is concluded that competitive adsorption of the reaction products from the ring cleavage of VO-TPP is negligible and that the presence of hetero-atom containing compounds in realistic feedstocks can decrease the rate of metal removal significantly.

Aim: To report our experience with retroperitoneal laparoendoscopic single-site (LESS) ureterolithotomy for the management of large proximal ureteral stones. Patients and Methods: From July 2011 to April 2012, 20 patients underwent retroperitoneal LESS ureterolithotomy. The indications for the operation were impacted upper ureteral stones larger than 15 mm. A reusable elastic single-port device with 3 working channels was inserted through the 2.5-cm incision at the midpoint between the costal arch and iliac crest on the mid-axillary line. A rigid 10-mm 30° extra-long laparoscope was introduced for monitoring, and a combination of lengthened pre-bent and conventional laparoscopic instruments was used for handling. The surgical procedure was similar to conventional retroperitoneal laparoscopic ureterolithotomy. Results: Retroperitoneal LESS ureterolithotomy was completed in all of the patients. The mean stone size was 18.8 mm (range 16-28). The mean operative time was 108 min (range 75-140). Significant bleeding was not observed, and no major intraoperative complications occurred in any of the patients. The mean hospital stay was 4.4 days (range 3-7). Conclusions: Retroperitoneal LESS ureterolithotomy, using a reusable elastic single-port device, is technically feasible and safe, and the combination of conventional and pre-bent laparoscopic instruments represents an attractive option for retroperitoneal LESS.

• To report our experience with retroperitoneal laparoscopic dismembered pyeloplasty for pelvi-ureteric junction (PUJ) obstruction in children.• Between March 2007 and December 2009, 38 children with PUJ obstruction (mean age 8.3 years, range 3-14) underwent retroperitoneal laparoscopic dismembered pyeloplasty. • A ureteric catheter was inserted into the mid-ureter cystoscopically. During pyeloplasty, the proximal end of the ureteric catheter was extracorporeally sutured to the distal end of the JJ stent with silk. • The ureteric catheter was then pulled down and the stent was pulled antegrade into the ureter and bladder.• The approach was retroperitoneal in all patients except one who required open conversion. The overall mean operative time was 162 min (range 145-210 min) and this appeared to decrease with experience. Mean hospital stay was 4 days (range 3-7 days). • Mean follow-up was 20.2 months (range 6-32 months). Satisfactory drainage with decreased hydronephrosis was documented in all patients on ultrasonography and intravenous urography.• Our study shows that retroperitoneal laparoscopic dismembered pyeloplasty is a feasible and effective alternative to open pyeloplasty with a relatively minimal complication rate in children 3 years of age and older, but it should be undertaken by experienced laparoscopic surgeons.

Objective • To report our experience with retroperitoneal laparoscopic dismembered pyeloplasty for pelvi-ureteric junction (PUJ) obstruction in children. Patients and methods • Between March 2007 and December 2009, 38 children with PUJ obstruction (mean age 8.3 years, range 3-14) underwent retroperitoneal laparoscopic dismembered pyeloplasty. • A ureteric catheter was inserted into the mid-ureter cystoscopically. During pyeloplasty, the proximal end of the ureteric catheter was extracorporeally sutured to the distal end of the JJ stent with silk. • The ureteric catheter was then pulled down and the stent was pulled antegrade into the ureter and bladder. Results • The approach was retroperitoneal in all patients except one who required open conversion. The overall mean operative time was 162 min (range 145-210 min) and this appeared to decrease with experience. Mean hospital stay was 4 days (range 3-7 days). • Mean follow-up was 20.2 months (range 6-32 months). Satisfactory drainage with decreased hydronephrosis was documented in all patients on ultrasonography and intravenous urography. Conclusion • Our study shows that retroperitoneal laparoscopic dismembered pyeloplasty is a feasible and effective alternative to open pyeloplasty with a relatively minimal complication rate in children 3 years of age and older, but it should be undertaken by experienced laparoscopic surgeons.

The nonisothermal crystallization kinetics of modified bamboo fiber/polycaprolactone (MBF/PCL) composites was investigated by differential scanning calorimetry (DSC) at different cooling rates. The results were studied by a direct fitting of the experimental data to various macrokinetic models, namely, Avrami, Ozawa, and Mo models. Both the Avrami analysis modified by Jeziorny and the method developed by Mo could describe the nonoisothermal crystallization of the composites very well, but the Ozawa analysis could not give an adequate description. Kinetic parameters such as the Avrami exponent (n), the kinetic crystallization rate constant (Zc), the peak temperatures (Tpeak) and the half-time of crystallization (t1/2) etc. were determined at various scanning rates. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Objectives To describe a novel technique of double-J stenting in laparoscopic pyeloplasty. Methods Between January 2008 and July 2009, 22 patients with ureteropelvic junction obstruction underwent retroperitoneal laparoscopic dismembered pyeloplasty. A ureteral catheter was inserted into the midureter cystoscopically. During pyeloplasty, the ureteral catheter was pushed up and grasped outside the body through the laparoscopic port. Its proximal end was extracorporeally sutured to the distal end of the double-J stent with a silk. The length of the silk was about that of the urethra. The ureteral catheter was then pulled down until its proximal end exited the external orifice of the urethra, while the stent was pulled smoothly and antegrade into the ureter and bladder. After the proximal end of the stent was positioned in the renal pelvis, the silk was cut and the ureteral catheter was removed. Results The stent was correctly placed in all these patients without any stent-related complications. The mean time for cystoscopy to place the ureteral catheter was 5 minutes, 10 seconds, and the mean time for the stent placement was 2 minutes, 45 seconds. The mean time for a total of 2 parts was 9 minutes, 15 seconds. Conclusions Our new method of laparoscopic double-J stenting is reliable and easily reproducible with the combined advantages of the antegrade and retrograde approaches to eliminate the risk of the stenting failure.