Endoscopic transluminal pancreatic necrosectomy using a self-expanding metal stent and high-flow water-jet system

Walled-off pancreatic necrosis and a pancreatic abscess are the most severe complications of acute pancreatitis. Surgery in such critically ill patients is often associated with significant morbidity and mortality within the first few weeks after the onset of symptoms. Minimal invasive approaches with high success and low mortality rates are therefore of considerable interest. Endoscopic therapy has the potential to offer safe and effective alternative treatment. We report here on 3 consecutive patients with infected walled-off pancreatic necrosis and 1 patient with a pancreatic abscess who underwent direct endoscopic necrosectomy 19-21 d after the onset of acute pancreatitis. The infected pancreatic necrosis or abscess was punctured transluminally with a cystostome and, after balloon dilatation, a non-covered self-expanding biliary metal stent was placed into the necrotic cavity. Following stent deployment, a nasobiliary pigtail catheter was placed into the cavity to ensure continuous irrigation. After 5-7 d, the metal stent was removed endoscopically and the necrotic cavity was entered with a therapeutic gastroscope. Endoscopic debridement was performed via the simultaneous application of a high-flow water-jet system; using a flush knife, a Dormia basket, and hot biopsy forceps. The transluminal endotherapy was repeated 2-5 times daily during the next 10 d. Supportive care included parenteral antibiotics and jejunal feeding. All patients improved dramatically and with resolution of their septic conditions; 3 patients were completely cured without any further complications or the need for surgery. One patient died from a complication of prolonged ventilation severe bilateral pneumonia, not related to the endoscopic procedure. No procedure related complications were observed. Transluminal endoscopic necrosectomy with temporary application of a self-expanding metal stent and a high-flow water-jet system shows promise for enhancing the potential of this endoscopic approach in patients with walled-off pancreatic necrosis and/or a pancreatic abscess.

Formation Control for Water-Jet USV Based on Bio-Inspired Method

The formation control problem for underactuated unmanned surface vehicles(USVs) is addressed by a distributed strategy based on virtual leader strategy. The control system takes account of disturbance induced by external environment. With the coordinate transformation, the advantage of the proposed scheme is that the control point can be any point of the ship instead of the center of gravity. By introducing bio-inspired model, the formation control problem is addressed with backstepping method. This avoids complicated computation, simplifies the control law,and smoothes the input signals. The system uniform ultimate boundness is proven by Lyapunov stability theory with Young inequality. Simulation results are presented to verify the effectiveness and robust of the proposed controller.

Natural orifice transluminal endoscopic wedge hepatic resection with a water-jet hybrid knife in a non-survival porcine model

AIM: To explore the feasibility of a water-jet hybrid knife to facilitate wedge hepatic resection using a natural orifice transluminal endoscopic surgery (NOTES) approach in a non-survival porcine model. METHODS: The Erbe Jet2 water-jet system allows a needleless, tissue-selective hydro-dissection with a pre-selected pressure. Using this system, wedge hepatic resection was performed through three natural routes (trans-anal, trans-vaginal and trans-umbilical) in three female pigs weighing 35 kg under general anesthesia. Entry into the peritoneal cavity was via a 15-mm incision using a hook knife. The targeted liver segment was marked by an APC probe, followed by wedge hepatic resection performed using a water-jet hybrid knife with the aid of a 4-mm transparent distance soft cap mounted onto the tip of the endoscope for holding up the desired plane. The exposed vascular and ductal structures were clipped with Endoclips. Hemostasis was applied to the bleeding cut edges of the liver parenchyma by electrocautery. After the procedure, the incision site was left open, and the animal was euthanized followed by necropsy. RESULTS: Using the Erbe Jet2 water-jet system, trans-anal and trans-vaginal wedge hepatic resection was successfully performed in two pigs without laparoscopic assistance. Trans-umbilical attempt failed due to an unstable operating platform. The incision for peritoneal entry took 1 min, and about 2 h was spent on excision of the liver tissue. The intra-operative blood loss ranged from 100 to 250 mL. Microscopically, the hydro-dissections were relatively precise and gentle, preserving most vessels. CONCLUSION: The Erbe Jet2 water-jet system can safely accomplish non-anatomic wedge hepatic resection in NOTES, which deserves further studies to shorten the dissection time.

Trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife:A pilot animal study

AIM:To investigate the feasibility and safety of Natural orifice trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife in a non-survival porcine model.METHODS:Pure natural orifice transluminal endoscopic surgery(NOTES) cholecystectomy was performed on three non-survival pigs,by transumbilical approach,using a water-jet hybrid-knife. Under general anesthesia,the following steps detailed the procedure:(1) incision of the umbilicus followed by the passage of a double-channel flexible endsocope through an overtube into the peritoneal cavity;(2) establishment of pneumoperitoneum;(3) abdominal exploration;(4)endoscopic cholecystectomy:dissection of the gallbladder performed using water jet equipment,ligation of the cystic artery and duct conducted using nylon loops;and(5) necropsy with macroscopic evaluation.RESULTS:Transumbilical endoscopic cholecystectomy was successfully completed in the first and third pig,with minor bleedings. The dissection times were 137and 42 min,respectively. The total operation times were 167 and 69 min,respectively. And the lengths of resected specimen were 6.5 and 6.1 cm,respectively.Instillation of the fluid into the gallbladder bed produced edematous,distended tissue making separation safe and easy. Reliable ligation using double nylon loops insured the safety of cutting between the loops.There were no intraoperative complications or hemodynamic instability. Uncontrolled introperative bleeding occurred in the second case,leading to the operation failure.CONCLUSION:Pure NOTES trans-umbilical cholecystectomy with a water-jet hybrid-knife appears to be feasible and safe. Further investigation of this technique with long-term follow-up in animals is needed to confirm the preliminary observation.

Water-Jet Cavitation Shock Bulging as Novel Microforming Technique

With the continuous expansion of the application range of microelectromechanical systems,microdevice forming technology has achieved remarkable results.However,it is challenging to develop new microforming processes that are low cost,environmentally friendly,and highly flexible;the high-energy shock wave in a cavitation bubble's collapse process is used as the loading force.Herein,a new process for the microbulging of the water-jet cavitation is proposed.A series of experiments involving the water-jet cavitation shock microbulging process for TA2 titanium foil is performed on an experimental system.The microforming feasibility of the water-jet cavitation is investigated by characterizing the shape of the formed part.Subsequently,the effects of the main parameters of the water-jet cavitation on the bulging profile,forming depth,surface roughness,and bulging thickness distribution of TA2 titanium foil are revealed.The results show that the plastic deformation increases nonlinearly with the incident pressure.When the incident pressure is 20 MPa,the maximum deformation exceeds 240 pm,and the thickness thinning ratio changes within 10%.The microbulging feasibility of water-jet cavitation is verified by this phenomenon.

The Propulsive Force of the Water-jet to the Flying Weft in Water-jet Looms

In order to study the propulsive force on the water-jet to the flying weft in water-jet looms, a dynamic model has been established. Based on the analysis and example testing, an experiential formula of the propulsive force of the water-jet to the flying weft is obtained for the first time. The formula will profit the further research of the water-jet weft insertion and the production of textile.

Influence of long and short guide vanes on hydraulic performance of water-jet pump

Different guide vane structures will affect the flow inside the pump,and then affect the transformation of the pressure energy and kinetic energy,and change the velocity distribution of the pump outlet.In order to study the influence of long and short guide vanes on the water-jet pump,on the basis of conventional design,eight schemes of guide vane with different vertical heights were designed in the method of computational fluid dynamics for numerical calculation,the performance curve of water-jet pumps with different long and short guide vanes was obtained,and finally the influence of different guide vanes on hydraulic performance and internal flow was analyzed.The results show that all of schemes reducing the height of blade can improve the head and efficiency.In the schemes reducing the height on the shroud,the guide vanes that the height of the blade is equal to the height difference between hub and shroud in impeller have the highest head and efficiency.In all schemes decreasing the blade height,with the increase of the height difference,the velocity increases gradually and the distribution of turbulence kinetic energy becomes more reasonable in the guide vane outlet.The schemes reducing the height on the hub have more reasonable distribution of velocity and turbulence kinetic energy according to schemes reducing the height on the shroud.The guide vanes of long and short blades can be used to stagger the position of the diffusion flow generated by adjacent blades,which can reduce the effect of the velocity circulation and make the flow of the outlet position more stable.

Study of Water Jet Impulse in Water-Jet Looms

The watar jet impulse is brought forward to study the traction force of the water jet to the flying weft in water-jet looms. The distribution of the water jet impulse in the shed is tested by a sensor, and the influence of water jet parameters on the water jet impulse is analyzed.

Prediction and Analysis of Surface Quality of Northeast China Ash Wood during Water-Jet Assisted CO_(2) Laser Cutting

As a natural and environmentally friendly renewable material,Northeast China ash wood(NCAW)(Fraxinus mandshurica Rupr.)was cut by water-jet assisted CO_(2) laser(WACL),the surface quality was evaluated by surface roughness of cut section.The surface roughness was measured by three-dimensional(3D)profilometry.Furthermore,the micromorphology of machined surface was observed by scanning electronic microscopy(SEM).Carbon content changes of machined surface were measured by energy dispersive spectrometer(EDS).A relationship between surface roughness and cutting parameters was established using response surface methodology(RSM).It is concluded that the cutting speed,laser power and water pressure played an important role in surface roughness of cut section.The surface roughness increased as an increase in laser power.It decreased caused by increasing of cutting speed and water pressure.Measurements revealed that the surface quality of NCAW part was improved using the optimized combination of cutting parameters.The established quadratic mathematical model of a good prediction is helpful for matching suitable cutting parameters to obtain expected surface quality.

The kinematic Design of Beating-up Mechanism for Water-jet Loom Series Modified from Air-jet Loom

For Toyoda looms with air-jet weft insertion,the beat-ing-up mechanisms together with those of Tsudakomawater-jet looms are analyzed.Then by changing thecrank length of the four-bar-linkage for the air-jetlooms to get four specifications of reed travel correspond-ing to the series of Tsudakoma water-jet looms,it canbe proved by comparisons of displacements,velocities,accelerations and transmission pressure angles that thosetwo series of mechanisms have very similar kinematicproperties.So the possibility of developing a series of wa-ter-jet looms modified from Toyoda air-jet looms isproved.It is beneficial to save the machine cost andbroaden the machine types.

苯乙烯-丙烯酸丁酯乳液性能的研究

介绍了以苯乙烯、丙烯酸丁酯和丙烯酸为反应单体,过硫酸铵为引发剂苯丙乳液的合成工艺。通过实验确定了新产品的原料配比以及主要技术性能指标,同时讨论了单体、引发剂、乳化剂及温度对乳液性能的影响。结果表明,以苯乙烯、丙烯酸丁酯和丙烯酸为主要单体的苯丙乳液具有优良的化学稳定性。

生产球形纳米碳酸钙新型碳化反应器开发研究

已经工业化的纳米碳酸钙生产方法所生产的产品多为立方形和纺锤形,目前还没有生产球形纳米碳酸钙的工业方法。给出了一种生产球形纳米碳酸钙的喷射—乳化新型组合式碳化反应器,并进行了小试和中试实验研究。在小型实验装置上,采用正交试验的方法,确定出粒度分布窄的球形纳米碳酸钙的最佳反应条件为:温度15℃,氢氧化钙浆液质量浓度65 g/L,气液体积比51∶。在完成小试的基础上,建成了年产60 t纳米碳酸钙的中试实验装置,并成功制备出平均粒径80 nm球形纳米碳酸钙。

柴油乳化实验研究

本文参考近年来国内外学者的研究成果 ,使用非离子及阴离子表面活性剂 ,采用HLB值法筛选和复配方法得到稳定性良好的乳化剂 ,选用该乳化剂对柴油乳化后 ,在 1135单缸柴油机和 2 135双缸柴油机上进行了实际运行实验 ,与原机柴油比较 ,平均节油率为 14 % ,平均烟度降低率可达 5 2 % ,平均NOx降低率超过 7% ;而且该乳化剂生产成本较低 ,经济性好 ,具有广阔发展前景。

苯丙乳液的合成

介绍了苯丙乳液的合成工艺、用途、优缺点及目前存在的差距,通过实验确定了新产品的原料配比以及主要技术性能指标,同时讨论了单体、引发剂、乳化剂及温度对乳液性能的影响,结果表明:以丙烯酸丁酯和苯乙烯为主要单体的苯丙乳液具有优良的化学稳定性。

油包水型乳化柴油试验研究

使用非离子及阴离子表面活性剂,采用HLB值法筛选和复配方法得到稳定性良好的乳化剂。选用该乳化剂对柴油乳化,在1135单缸柴油机和2135双缸柴油机上进行实际运行实验,与原机柴油比较,油耗及排放都有不同程度改善。该乳化剂产生成本较低,具有广泛发展前景。

PS系列煤浆预处理器

重点阐述水喷射式乳化器和管道混合器组成的PS系列煤浆预处理器工作原理、结构参数的研究,并介绍了该系列设备的规格和使用情况。

浮选剂乳化系统在选煤厂的推广应用

介绍水喷射式乳化器的结构和工作原理,浮选剂乳浊液添加系统的安装、使用中的注意事项以及在镇城底等3座选煤厂的推广应用情况。

SM型阳离子咪唑啉乳化剂乳化沥青应用技术条件的研究

本文以SM型阳离子咪唑啉乳化剂,对较难乳化的兰炼100~#路用沥青提出了应用技术条件,为公路工程提供了基础应用数据。

WMH─Ⅰ型脉冲式油水乳化器及其特性

介绍了ＷＭＨ－Ⅰ型脉冲式油水乳化器的结构及其操作特性。试验表明，该种乳化器的操作参数可在较宽的范围内变化，其停留时间的均值在６．５～８．５秒之间，无因次方差在０．２～０．４之间，乳液粒径的均值小于３．２μｍ，均方差在１．４～１．７μｍ之间。湍流状态下的摩擦系数ｆ小于２。

新型染料防尘剂的研究

采用工业脂肪酸和环氧乙烷加成法研制成乳化剂 ,进而获得一种新型染料防尘剂。试验结果表明此防尘剂具有较好的防尘效果 ,对染料的色光、强度无影响 。