Coherent acoustic phonons in a coupled hexagonal boron nitride-graphite heterostructure.

Femtosecond optically excited coherent acoustic phonon modes (CAPs) are investigated in a free-standing van der Waals heterostructure composed of a 20-nm transparent hexagonal boron nitride (hBN) and a 42-nm opaque graphite layer. Employing ultrafast electron diffraction, which allows for the independent evaluation of strain dynamics in the constituent material layers, three different CAP modes are identified within the bilayer stack after the optical excitation of the graphite layer. An analytical model is used to discuss the creation of individual CAP modes.

Droplet etching of deep nanoholes for filling with self-aligned complex quantum structures.

Strain-free epitaxial quantum dots (QDs) are fabricated by a combination of Al local droplet etching (LDE) of nanoholes in AlGaAs surfaces and subsequent hole filling with GaAs. The whole process is performed in a conventional molecular beam epitaxy (MBE) chamber. Autocorrelation measurements establish single-photon emission from LDE QDs with a very small correlation function g ((2))(0)≃ 0.

A nitric oxide scavenger protects against pulmonary inflammation following hemorrhagic shock.

Hemorrhagic shock (HS) elicits an inflammatory response characterized by increased cytokine production and recruitment of PMN which we previously found to be iNOS dependent. In this study we attempted to remove excess induced-NO by administration of the NO scavenger, NOX, with the goal of suppressing proinflammatory signaling and reducing organ damage. Rats subjected to HS (MAP = 40 mmHg for 100 min) followed by resuscitation and examined 24 h later demonstrated histological signs of lung injury including pulmonary edema as well as an 8.

[Case report: emergency surgery of a giant scrotal hernia].

We present the case of a 61-year-old patient, who had developed a giant scrotal hernia during the course of 30 years. The patient was transferred to our service after stabilization of hemorrhagic shock due to bleeding from varicosis of the giant scrotal sack. The urgent operation was performed by resection of parts of small intestine, colon ascendens, transversum, and the left testis.

Self-guided robotic camera control for laparoscopic surgery compared with human camera control.

Background: In laparoscopic surgery, the surgeon no longer has direct visual control of the operation area, and a camera assistant who maneuvers the laparoscope is essential. Problems of cooperation between the two naturally arise, and a robotic assistant that automatically controls the laparoscope can offer a highly desirable alternative to this situation.

Methods: A self-guided robotic camera control system (SGRCCS) based upon a color tracking method has been developed and its use evaluated in 20 cases of laparoscopic cholecystectomy and compared with using human camera control.

Endoscopic stapling diverticulostomy for Zenker's diverticulum.

Endoscopic stapling diverticulostomy (ESD) using an endostapler is a modification of the standard endoscopic treatment of Zenker's diverticulum (ZD). It is characterized by complete myotomy of the upper esophageal sphincter, with division of the common wall between diverticulum and esophagus, followed by immediate simultaneous closure of the divided edges with the staples. ESD was performed on 21 patients with ZD between January 1996 and October 1997.

Long-term follow-up of endoscopic therapy in patients with post-surgical biliary leakage.

Background/aims: Leakage is a rare complication of biliary surgery which is thought to follow a benign course after appropriate treatment. However there is a paucity of long-term follow-up data.

Patients And Methods: In this retrospective analysis, we present our experience with 21 patients in whom a biliary leakage was diagnosed following conventional and laparoscopic cholecystectomy (n = 14) or other types of biliary surgeries such as liver transplantation or segmental liver resection.

[Technical requirements and possibilities of teleconsultation in laparoscopic interventions].

Recent developments in robot technology and communication media have opened the way for their use in various medical techniques. Automated camera guidance as well as new telecommunication systems make it possible to carry out extensive laparoscopic operations precisely and to provide teaching assistance from great distances (so-called telepreceptorship). Long-term cost reduction, reduction of surgical complications and the improvement of quality standards are some of the benefits which could be realized by use of such systems.

[Possibilities of telecommunications in surgery].

In contrast to telesurgery, telepresence involves only the audiovisual dialogue between the local surgeon and a remote expert; the latter, however, is able to actively monitor the operation by giving his judgement and recommendations. Under clinical conditions, telepresence may have the potential to facilitate intraoperative consultation of remote experts or even tele-assistance. Technical requirements consist of a suitable telemanipulation device (remotely controlled camera and indicator) and a high-duty communication system for real-time transmission of the operating site and the control signal.

[Bile duct lesions in laparoscopic cholecystectomy].

Laparoscopic cholecystectomy is both resulting in a slightly higher incidence of biliary lesions and a change of prevalence of the type of lesions. Damage to the biliary system occurs in 4 different types: The most severe case is the lesion with a structural defect of the hepatic or common bile duct with (IVa) or without (IVb) vascular injury. Tangential lesions without structural loss of the duct should be denominated as type III (IIIa with additional lesion to the vessels, type IIIb without).

[Role of i.v. cholangiography and ultrasonography in preoperative diagnosis before laparoscopic cholecystectomy].

In a prospective clinical study the relevance of i.v. cholangiography and ultrasonography for preoperative diagnosis before laparoscopic cholecystectomy was assessed.

[Laparoscopic cholecystectomy: ERCP as standard preoperative diagnostic technique].

In a prospective study 250 patients with proven cholelithiasis and clinical, biochemical and ultrasound indications for laparoscopic cholecystectomy (LC) underwent endoscopic retrograde cholangiography (ERCP) and (if bile-duct stones had been shown) endoscopic papillotomy (EPT). The biliary system was demonstrated in 229 patients (91.6%).

Prospective evaluation of the use of endoscopic retrograde cholangiography prior to laparoscopic cholecystectomy.

Preoperative cholangiography and subsequent removal of bile duct stones may increase the efficacy of laparoscopic cholecystectomy and reduce the rate of conversion to open cholecystectomy. Since there is little data on the incidence of choledocholithiasis in this group of patients, we undertook a prospective study on the routine performance of ERC in 288 patients selected for laparoscopic cholecystectomy. ERC succeeded in 264 of the 288 patients (91.

[Technique of laparoscopic cholecystectomy].

A new technique for laparoscopic cholecystectomy is described which regards as far as possible the conventional approach to cholecystectomy. Positioning of the operating team is identical to normal cholecystectomy, and the surgeon is able to use both hands to operate since the camera is handled by the assistant. Dissection of the infundibulum is performed in the socalled "tease-and-tear" technique.

[An anatomic study of the pancreatic lymphatics. Review of the summary and an abridged version of the original text].

A detailed study of the lymphatics around the pancreas was carried out in order to provide a theoretic basis for ideal lymph-node resection in radical cancer operations. The following results were obtained as a result of minute macroscopic dissection of the lymphatics. Three major pathways are identified on the anterior surface of the head of the pancreas.