Direct observation of cation diffusion driven surface reconstruction at van der Waals gaps.

Weak interlayer van der Waals (vdW) bonding has significant impact on the surface/interface structure, electronic properties, and transport properties of vdW layered materials. Unraveling the complex atomistic dynamics and structural evolution at vdW surfaces is therefore critical for the design and synthesis of the next-generation vdW layered materials. Here, we show that Ge/Bi cation diffusion along the vdW gap in layered GeBi2Te4 (GBT) can be directly observed using in situ heating scanning transmission electron microscopy (STEM). The cation concentration variation during diffusion was correlated with the local Te6 octahedron distortion based on a quantitative analysis of the atomic column intensity and position in time-elapsed STEM images. The in-plane cation diffusion leads to out-of-plane surface etching through complex structural evolutions involving the formation and propagation of a non-centrosymmetric GeTe2 triple layer surface reconstruction on fresh vdW surfaces, and GBT subsurface reconstruction from a septuple layer to a quintuple layer. Our results provide atomistic insight into the cation diffusion and surface reconstruction in vdW layered materials.

[Treatment of urosepsis induced by extracorporeal shock wave lithotripsy: analysis of 4 cases].

OBJECTIVE: To evaluate the strategy for management of urosepsis after extracorporeal shock wave lithotripsy (ESWL). METHODS: The clinical data were analyzed in 4 cases of urosepsis caused by ESWL during the period from January, 2008 to October 2011. RESULTS: Two of the patients had kidney stones and two had ureteral stones. Analysis of urine bacterial culture revealed the presence of E. coli in 2 cases, Klebsiella pneumoniae in 1 case and Pseudomonas putida combined E. coli in 1 case. All the 4 patients were monitored for ECG, blood pressure and oxygen saturation, and received fluid replacement and anti-inflammatory therapy. The vital signs of the patients became stable after 5-11 days (mean 6.75 days). Three patients underwent ureteroscopic lithotripsy, and 1 patient had emergency ureteral stent indwelling. All the 4 patients were cured and discharged. CONCLUSION: ESWL is more likely to cause urosepsis in patients with ureteral stones and urinary infection, for which early nonsurgical interventions should be administered immediately after the diagnosis is established.

[A model for predicting the success rate of a single extracorporeal shock wave lithotripsy session for single renal calculus].

OBJECTIVE: To evaluate the factors affecting the efficacy of extracorporeal shock wave lithotripsy (ESWL) and establish a model for predicting the success rate of a single ESWL session in the treatment of single renal calculus. METHODS: Between January 2008 and February 2010, 325 patients underwent ESWL monotherapy and were followed up for at most 3 months. The correlations between the outcome of a single ESWL session and the patients' age, gender, body mass index (BMI), disease duration, pretreatment renal colic, hematuria, urinary irritation symptoms, stone location, stone laterality, stone length and stone width were analyzed. The statistically significant factors identifies were further analyzed by multivariate logistic regression, and the predictive model was established. RESULTS: The stone-free rate of ESWL was 76.9%. Univariate analysis found that the patients' age, stone laterality, stone location, disease duration, pretreatment hematuria, stone length and width all significantly affected the outcome of the treatment. Logistic regression analysis indicated the factors including disease duration, pretreatment hematuria, stone length and stone width determined the success rate of the treatment. Hosmer and Lemeshow Test showed a good fitting of the predictive model (Χ(2)=18.144, df=8, P=0.168) with an overall accuracy of 87.4%. CONCLUSION: Disease duration, pretreatment hematuria, stone length and width are independent factors affecting the outcome of a single ESWL session for single renal calculus.

[Extracorporeal shock wave lithotripsy for lower urinary tract stones: complications and the contributing factors].

OBJEVTIVE: To analyze the complications of extracorporeal shock wave lithotripsy (ESWL) for treatment of lower urinary tract stones and identify the factors contributing to the complications. METHODS: We retrospectively analyzed the postoperative complications of ESWL in 83 patients with lower urinary tract stones and their association with the patients' age, height, body weight, body mass index (BMI), stone features, shock wave times, and shock wave energy. RESULTS: Of the 83 cases treated with ESWL, 72.3% (60 cases) showed gross hematuria, 27.7% (23 cases) complained of pain, and 25.3% (21 cases) had both pain and gross hematuria. None of the patients reported vomiting, skin rash, flatulence, gastrointestinal bleeding or other complications. Patients with postoperative gross hematuria, pain, and both had significantly greater stone length, stone width and more shock body times than those without these complications (P<0.01 or P<0.05). Patients with gross hematuria had significantly lower height than those without complications (P<0.05). CONCLUSION: The common complications of ESWL for lower urinary tract stones include hematuria and pain. The patient's height, stone length, stone width and shock times are important factors contributing to these postoperative complications.

[Extracorpreal shockwave lithotripsy in treatment of bilateral ureteral calculi with renal colic during emergency].

OBJECTIVE: To evaluate the clinical efficacy of extracorporeal shockwave lithotripsy (ESWL) for bilateral ureteral stones with renal colic in emergency. METHODS: We retrospectively analyzed the clinical data of 86 patients suffered with sudden renal colic due to bilateral ureteral stones and treated with ESWL between January 2005 and January 2009. RESULTS: The success rate was 74.4% after a single ESWL session, and the overall success rate was 82.6%. Significant difference in stone length was observed between successful group and failed group (P<0.01). The stone position did not produce significant impact on the outcome of the treatment (P>0.05). CONCLUSION: ESWL is an effective treatment modality in emergency for small-length and short-term obstruction bilateral ureteral stones with remal colic.

[Analysis of the outcome of extracorporeal shock wave lithotripsy for renal calculia].

OBJECTIVE: To evaluate the factors affecting the efficacy of extracorporeal shock wave lithotripsy (ESWL) for renal calculi. METHODS: Between January, 2004 and January, 2007, 316 patients (212 men and 104 women) with renal stone underwent ESWL. The correlations of the patients' age, gender, body mass index (BMI), disease course, pain, hematuria, stone size, location, side, number and hydronephrosis to the outcome of the treatment was analyzed. The treatment success was defined as complete clearance of the stones or residual stone fragments <0.4 cm, and ESWL was considered unsuccessful with residual stones>0.4 cm. RESULTS: The overall success rate was 75.3% (238/316) in these patients. Significant difference in stone clearance rates was observed in patients with stone size of 0.5-1.0 cm (90.3%, 167/185), 1.0-2.0 cma(69.6%, 55/79), and >2.0 cm (30.8%, 16/52) (P<0.05). The success rates differed significantly between cases of pelvic stones (83.1%, 118/142) and those of caliceal stones (69.0%, 120/174) (P<0.05). But in cases of caliceal stones, the success rates were comparable between cases with stones at the upper calyx (71.7%, 43/60), middle calyx (68.9%, 31/45), and lower calix (66.7%, 46/69) (P>0.05). Patients with single stones had significantly higher success rate (82.9%,170/205) than those with multiple stones (61.3%, 68/111) (P<0.05). The patients' gender, age, disease course, pain, hematuria, stone side and hydronephrosis did not produce significant impact on the outcome of the treatment (P>0.05). CONCLUSION: Stone size, location and quantity are significant independent factors affecting the outcome of ESWL for renal stones.

[Factors affecting the outcome of extracorporeal shockwave lithotripsy for upper urinary tract stones].

OBJECTIVE: To investigate the factors affecting the efficacy of extracorporeal shockwave lithotripsy (ESWL) for upper urinary tract stones. METHODS: Between January 2003 and January 2006, 366 patients with upper urinary tract stone underwent ESWL, and the results were identified by regular KUB/IVU or ultrasonography and evaluated 3 months after the treatment. The treatment success was defined as complete clearance of the stones without residual fragments. The stone-free rate was analyzed in relation to the stone features and the patients' clinical characteristics, and the factors identified to significant affect the results were further analyzed using multivariate regression analysis. RESULTS: Three months after the treatment, the overall stone-free (success) rate was 63.4% (232/366) in these patients. Chi square test and t test identified the disease course, stone length and width as the factors with significant impact on the stone-free rate. Multivariate analysis excluded the disease course and stone width from the logistic regression model, and identified the stone length as the independent factor affecting the outcome of ESWL. CONCLUSION: The stone length is an independent factor influencing the efficacy of ESWL for upper urinary tract stones.

[Selection of the imaging modalities for diagnosis of renal trauma: experience with 74 cases].

OBJECTIVE: To explore the diagnostic approaches and values of the imaging modalities for traumatic renal injuries. METHODS: The clinical records of 74 cases of renal trauma treated in Nanfang Hospital were retrospectively reviewed to assess the diagnostic value of intravenous urography (IVU), type B ultrasonography and computed tomography (CT). RESULTS: The positivity rates by IVU, type B ultrasonography, and CT were 89% (43/49), 80% (55/68) and 100% (51/51) respectively for the diagnosis of renal trauma. CONCLUSION: IVU is rapid and convenient, ultrasonography less costly and invasive, and CT accurate for diagnosis of renal traumas.

[Application of self-controlled breathing technique in respiratory gating that triggers the shockwave for lithotripsy of urinary calculi].

OBJECTIVE: To review our experience with the application of respiratory gating technique in extracorporeal shock wave lithotripsy (ESWL). METHODS: According to the established criteria 424 patients with urinary calculi were included in this study to received ESWL. These patients were divided into three groups, in which different breathing techniques were used for ESWL: group A with free breathing, group B with basically normal breathing except for the breath-holding upon each shockwave triggering, and group C with controlled breathing acquired from preoperative training. All the patients were followed up from 3 to 6 months, during the period of which the effect of ESWL was observed and recorded for comparative appraisal of the therapeutic efficacy. RESULTS: The therapeutic effect significantly differed between the groups (P < 0.01), with the best effect recorded in group C (96.40%), followed by group A (83.87%) immediately before group B (86.67%), indicating that the essential difference occurred between group C and groups A and B, but not between the latter two groups. None of the patients developed serious short-term complications. CONCLUSION: The application of breathing technique in respiratory gating for ESWL is safe and effective without causing serious complications.

Extracorporeal shock wave lithotripsy for difficulty in withdrawal of double J ureteral stents due to ureteral lithiasis.

OBJECTIVE: To explore the efficacy of extracorporeal shock wave lithotripsy (ESWL) to coping with lithiasis-induced difficulty in withdrawing double J ureteral stents. METHODS: This study includes 6 patients with difficulty in withdrawing the stents due to lithiasis, who were in the anterior prone position or posterior oblique supine position to receive ESWL treatment. The stones were localized by double-band intersection X-ray system. The treatment voltage of shock wave was 11.2 kV initially, which was gradually increased to 18.1 kV, and the shock wave attack amounted to 1,000 to 3,000 times in total. RESULTS AND CONCLUSION: After ESWL treatment, the encrusted double J stents were successfully withdrawn in all the 6 cases, without causing any morbidity related to the use of ESWL. Among the various techniques available for removing encrusted double J stents, ESWL appears to be the most effective and the least invasive modality.