Ultrasonographic percutaneous nephrolithotomy, with or without ureteral catheter

Introduction: Access by ultrasonography rather than fluoroscopy in addition to reducing radiation exposure to the patient and staff, is safe and effective. Access by ultrasonography is bi-planar and real-time compared to fluoroscopy, because it provides fewer side effects and more stone free rate. Objectives: To study the complications and outcome of PCNL (percutaneous nephrolithotomy) with or without using ureteral catheter. Patients and Methods: We studied 59 patients with at least 2 cm diameter of renal stone from January to December of 2018. After general anesthesia, 35 patients in the ureteral stent group were prepared in bladder lithotomy position. Then 5-French (Fr) ureteral catheters were introduced endoscopically in stone affected side and fixed to 16 Fr urethral Foley catheters in the patients. Other 24 patients in the non-stent group following anesthesia were directed to prone position instantly. In all of the patients, ultrasonography was performed in posterior auxiliary line below the ribs in prone position. Retrograde instillation of normal saline was performed through ureteral catheter in stent-group. Then we inserted 18G Chiba needle to desired calyx without needle holder guidance in all patients. Our approach according to probe was transverse. Results: Our patients comprised of 24 men and 35 women aged 24 to 66 years. Thirteen of them had no hydronephrosis and their stone sizes ranged from 21 mm to 65 mm. Patients in the ureteral stent group were more obese compared to the non-stent group (P=0.02) in addition to significantly more operation time (P=0.03). However hydronephrosis was not significantly different between groups (P=0.3). Postoperative residual stone rate, hospital stay days and complications (Fever, blood transfusion) were the same between both groups. Only urinary leak was more common in the non-stent group (P=0.04) Conclusion: Ultra-sonographic-PCNL without inserting ureteral catheter before surgery is conceivable especially in patients with lower body mass index (BMI). Advantages and complications are same in ureteral stent and non-stent patients except urinary leak that is more common in non-stent patients.

Self-Controlled Cleaving Method for Silicon DRIE Process Cross-Section Characterization

Advanced microsystems widely used in integrated optoelectronic devices, energy harvesting components, and microfluidic lab-on-chips require high-aspect silicon microstructures with a precisely controlled profile. Such microstructures can be fabricated using the Bosch process, which is a key process for the mass production of micro-electro-mechanical systems (MEMS) devices. One can measure the etching profile at a cross-section to characterize the Bosch process quality by cleaving the substrate into two pieces. However, the cleaving process of several neighboring deeply etched microstructures is a very challenging and uncontrollable task. The cleaving method affects both the cleaving efficiency and the metrology quality of the resulting etched microstructures. The standard cleaving technique using a diamond scriber does not solve this issue. Herein, we suggest a highly controllable cross-section cleaving method, which minimizes the effect on the resulting deep etching profile. We experimentally compare two cleaving methods based on various auxiliary microstructures: (1) etched transverse auxiliary lines of various widths (from 5 to 100 μm) and positions; and (2) etched dashed auxiliary lines. The interplay between the auxiliary lines and the etching process is analyzed for dense periodic and isolated trenches sized from 2 to 50 μm with an aspect ratio of more than 10. We experimentally showed that an incorrect choice of auxiliary line parameters leads to silicon “build-up” defects at target microstructures intersections, which significantly affects the cross-section profile metrology. Finally, we suggest a highly controllable defect-free cross-section cleaving method utilizing dashed auxiliary lines with the stress concentrators.

The Application of Space Vector in Calculation of Plinth Elevation Angle

The plinth elevation angle was related to the upstream slope and face slab shape of CFRD, as well as to the dam axis, which was very important in plinth design. Based on the space vector algorithm, the function established consists of plinth elevation angle and three-dimensional coordinate of key points of plinth line, which was taken as the unique input variable, and then the plinth elevation angle was directly obtained. The improved vector method with characteristics of high efficiency, simple input parameters and clear spatial concept, is obviously superior to the traditional geometric method which was deduce by doing the auxiliary line, and it has been widely applied and well verified in engineering.

Clinical and Radiographic Assessment of Periodontal Infrabony Defect Depth and Width and Their Correlation

Brief Background There is preliminary evidence of periodontal defect depth, number of walls and the width of infrabony defects exerting influence on the regenerative potential of particular therapeutic modality. Aim: To assess defect width and defect depth and their influence on pretreatment defect angle in patients affected with periodontal disease. Materials and Methods 60 untreated severe chronic or aggressive periodontitis patients were selected for the study. Digital intraoral periapical radiograph of defects in all patients were taken using RVG. First auxiliary line was drawn to represent tooth axis (AUX1). Perpendicular to this, a second auxiliary line (AUX2) was drawn that ran through most coronal margin of defect (M3). The depth of defect was measured as the distance between the base of bony defect and AUX2. The width of defect was the distance from coronal margin of bony defect to the root surface perpendicular to AUX1. Results In a total of 67 defects, the radiographic defect depth, defect width and defect angle for maxillary arch was 3.19 ± 1.19 mm , 2.82 ± 0.63 mm and 37.34 ± 9.47 ° respectively while these values for mandibular sites were 3.69 ± 0.92 mm, 2.87 ± 0.76 mm and 35.62 ± 7.08 ° respectively. Multilevel regression analysis revealed narrow defect angles to be related to deep infrabony defects, whereas the width of the interdental space to wide defects. Summary and Conclusion Defect dimensions are determined by the radius of action of microbial biofilm and the baseline defect angle of an infrabony defect would be a function of defect depth. Key Words: Periodontitis, periodontal therapy, vertical defects, radiography

Study on the Laser Precision Cutting System and Stainless Steel Microporous Cutting Technology

In order to improve the quality of laser cutting of stainless steel porous, the investigation on cutting 0.12mm stainless steel plates was carried out by a50W-powerbridgefiber laser cutting machine.The influence of the auxiliary line angle, laser power, and the pulse width and gas pressure on the cutting quality was studied in this paper.The results show that fewer defects was found on the samples when the cutting angle of auxiliary line was 90°and few splash orburrswas found on the samplesby 40 Wlaser power, with 56 μs pulse width and 1.3MPa gas pressure.

Research on the Last Train Connection in the Urban Mass Transit System

With the urban rail transit becoming more and more networked, determining the departure time of last trains has been an important part for the urban rail transit network operations organization. First analyze two aspects of passengers and vehicles to determine reasonable time intervals of last trains, then analyze last train departure time optimization, minimizing the total loss in the transfer station as the objective to build the mathematical model, by adding and shifting line at the transfer station to reduce the connection direction loss, an auxiliary line being added or not according to the operating time so as to determine the final operation result. Finally, use the Beijing subway to verify and the result shows that the method has practical significance for the improvement of urban rail transit operation organization.