External and internal rectal prolapse with their affiliated rectocele and enterocele, are associated with debilitating symptoms such as obstructed defecation, pelvic pain and faecal incontinence. Since perineal proced...External and internal rectal prolapse with their affiliated rectocele and enterocele, are associated with debilitating symptoms such as obstructed defecation, pelvic pain and faecal incontinence. Since perineal procedures are associated with a higher recurrence rate, an abdominal approach is commonly preferred. Despite the description of greater than three hundred different procedures, thus far no clear superiority of one surgical technique has been demonstrated. Ventral mesh rectopexy(VMR) is a relatively new and promising technique to correct rectal prolapse. In contrast to the abdominal procedures of past decades, VMR avoids posterolateral rectal mobilisation and thereby minimizes the risk of postoperative constipation. Because of a perceived acceptable recurrence rate, good functional results and low mesh-related morbidity in the short to medium term, VMR has been popularized in the past decade. Laparoscopic or robotic-assisted VMR is now being progressively performed internationally and several articles and guidelines propose the procedure as the treatment of choice for rectal prolapse. In this article, an outline of the current status of laparoscopic and robotic ventral mesh rectopexy for the treatment of internal and external rectal prolapse is presented.展开更多
Road throughput can be increased by driving at small inter-vehicle time gaps. The amplification of velocity disturbances in upstream direction, however, poses limitations to the minimum feasible time gap. This effect ...Road throughput can be increased by driving at small inter-vehicle time gaps. The amplification of velocity disturbances in upstream direction, however, poses limitations to the minimum feasible time gap. This effect is covered by the notion of string stability. String-stable behavior is thus considered an essential requirement for the design of automatic distance control systems, which are needed to allow for safe driving at time gaps well below 1 s. Using wireless inter-vehicle communications to provide real-time information of the preceding vehicle, in addition to the information obtained by common Adaptive Cruise Control （ACC） sensors, appears to significantly decrease the feasible time gap, which is shown by practical experiments with a test fleet consisting of six passenger vehicles. The large-scale deployment of this system, known as Cooperative ACC （CACC）, however, poses challenges with respect to the reliability of the wireless communication system. A solution for this scalability problem can be found in decreasing the transmission power and/or beaconing rate, or adapting the communications protocol. Although the main CACC objective is to increase road throughput, the first commercial application of CACC is foreseen to be in truck platooning, since short distance following is expected to yield significant fuel savings in this case.展开更多
Bulk polymerization of vinylene carbonate using t-butylperoxypivalate at 40℃gave colourless, high molecular weight poly(vinylene carbonate) (PVCA). Solutions of PVCA in acetone and DMF are not stable at 25℃and this ...Bulk polymerization of vinylene carbonate using t-butylperoxypivalate at 40℃gave colourless, high molecular weight poly(vinylene carbonate) (PVCA). Solutions of PVCA in acetone and DMF are not stable at 25℃and this degradation was studied. From measurements in DMF with unfractionated PVCA a Mark-Houwink equation was obtained:展开更多
Microsystems are increasingly being applied in harsh and/or inaccessible environments,but many markets expect the same level of functionality for long periods of time.Harsh environments cover areas that can be subject...Microsystems are increasingly being applied in harsh and/or inaccessible environments,but many markets expect the same level of functionality for long periods of time.Harsh environments cover areas that can be subjected to high temperature,(bio)-chemical and mechanical disturbances,electromagnetic noise,radiation,or high vacuum.In the field of actuators,the devices must maintain stringent accuracy specifications for displacement,force,and response times,among others.These new requirements present additional challenges in the compensation for or elimination of cross-sensitivities.Many state-of-the-art precision devices lose their precision and reliability when exposed to harsh environments.It is also important that advanced sensor and actuator systems maintain maximum autonomy such that the devices can operate independently with low maintenance.The next-generation microsystems will be deployed in remote and/or inaccessible and harsh environments that present many challenges to sensor design,materials,device functionality,and packaging.All of these aspects of integrated sensors and actuator microsystems require a multidisciplinary approach to overcome these challenges.The main areas of importance are in the fields of materials science,micro/nano-fabrication technology,device design,circuitry and systems,(first-level)packaging,and measurement strategy.This study examines the challenges presented by harsh environments and investigates the required approaches.Examples of successful devices are also given.展开更多
文摘External and internal rectal prolapse with their affiliated rectocele and enterocele, are associated with debilitating symptoms such as obstructed defecation, pelvic pain and faecal incontinence. Since perineal procedures are associated with a higher recurrence rate, an abdominal approach is commonly preferred. Despite the description of greater than three hundred different procedures, thus far no clear superiority of one surgical technique has been demonstrated. Ventral mesh rectopexy(VMR) is a relatively new and promising technique to correct rectal prolapse. In contrast to the abdominal procedures of past decades, VMR avoids posterolateral rectal mobilisation and thereby minimizes the risk of postoperative constipation. Because of a perceived acceptable recurrence rate, good functional results and low mesh-related morbidity in the short to medium term, VMR has been popularized in the past decade. Laparoscopic or robotic-assisted VMR is now being progressively performed internationally and several articles and guidelines propose the procedure as the treatment of choice for rectal prolapse. In this article, an outline of the current status of laparoscopic and robotic ventral mesh rectopexy for the treatment of internal and external rectal prolapse is presented.
文摘Road throughput can be increased by driving at small inter-vehicle time gaps. The amplification of velocity disturbances in upstream direction, however, poses limitations to the minimum feasible time gap. This effect is covered by the notion of string stability. String-stable behavior is thus considered an essential requirement for the design of automatic distance control systems, which are needed to allow for safe driving at time gaps well below 1 s. Using wireless inter-vehicle communications to provide real-time information of the preceding vehicle, in addition to the information obtained by common Adaptive Cruise Control （ACC） sensors, appears to significantly decrease the feasible time gap, which is shown by practical experiments with a test fleet consisting of six passenger vehicles. The large-scale deployment of this system, known as Cooperative ACC （CACC）, however, poses challenges with respect to the reliability of the wireless communication system. A solution for this scalability problem can be found in decreasing the transmission power and/or beaconing rate, or adapting the communications protocol. Although the main CACC objective is to increase road throughput, the first commercial application of CACC is foreseen to be in truck platooning, since short distance following is expected to yield significant fuel savings in this case.
文摘Bulk polymerization of vinylene carbonate using t-butylperoxypivalate at 40℃gave colourless, high molecular weight poly(vinylene carbonate) (PVCA). Solutions of PVCA in acetone and DMF are not stable at 25℃and this degradation was studied. From measurements in DMF with unfractionated PVCA a Mark-Houwink equation was obtained:
文摘Microsystems are increasingly being applied in harsh and/or inaccessible environments,but many markets expect the same level of functionality for long periods of time.Harsh environments cover areas that can be subjected to high temperature,(bio)-chemical and mechanical disturbances,electromagnetic noise,radiation,or high vacuum.In the field of actuators,the devices must maintain stringent accuracy specifications for displacement,force,and response times,among others.These new requirements present additional challenges in the compensation for or elimination of cross-sensitivities.Many state-of-the-art precision devices lose their precision and reliability when exposed to harsh environments.It is also important that advanced sensor and actuator systems maintain maximum autonomy such that the devices can operate independently with low maintenance.The next-generation microsystems will be deployed in remote and/or inaccessible and harsh environments that present many challenges to sensor design,materials,device functionality,and packaging.All of these aspects of integrated sensors and actuator microsystems require a multidisciplinary approach to overcome these challenges.The main areas of importance are in the fields of materials science,micro/nano-fabrication technology,device design,circuitry and systems,(first-level)packaging,and measurement strategy.This study examines the challenges presented by harsh environments and investigates the required approaches.Examples of successful devices are also given.
