Expression of hepatocyte low-density lipoprotein receptor-related protein is post-transcriptionally regulated by extracellular matrix

A clinical trial was conducted to assess the feasibility, safety, and efficacy of the atrial septal defect (ASD) occlusion system for transcatheter closure of secundum ASD and patent foramen ovale (PFO) after episodes of cerebral embolism. Occlusion was attempted in 200 patients aged 1 to 74 years (mean 32). The procedure failed in 26 patients (13%); the device was retrieved through a catheter in 20 and through surgery in 6 patients. Procedure-related complications necessitating surgical removal of the device included device embolization in 2, device entrapment within the Chiari network in 1, frame fracture in 1, and perforation of atrial wall in 2. All 6 patients experienced an uneventful postoperative course. An additional 11 patients (6%) underwent surgical removal of the device during follow-up. There were 163 patients (81%) with an implanted ASD occlusion system at follow-up of from 6 to 36 months (mean 17). Thrombus formation around the device was detected by transesophageal echocardiography in 9 patients 1 to 4 weeks after implantation. One of these patients (who had a coagulation factor XII deficiency) suffered a cerebral thromboembolism. Late atrial wall perforation (5, 6, and 8 months after implantation) occurred in 3 adult patients. Infectious endocarditis developed in 2 adult patients (1%). No late device embolization and no atrioventricular valve injury occurred. An asymptomatic device frame fracture was found in 14% and frame deformity in 4% of all patients during the follow-up period of >230 patient-years. Immediately after closure, a moderate/large residual shunt remained in 8% and a small shunt in 29% of patients. After 1 year, a moderate/large shunt was present in 2% and a small one in 26% of patients. During a total follow-up of 49 patient-years, only 1 of 46 patients with PFO had a transient neurologic event after the closure. The study indicates that patients with centrally situated secundum ASD and those with PFO after cerebral embolism can be treated with this system with a high success rate and an acceptable morbidity.     

Engineering Dynamic Scheduler for Work Manager

Provision of service to business and residential customers, network maintenance and fault repair are core activities of large telecommunications companies which involve thousands of technicians every day. Managing a large-sized workforce efficiently in a highly dynamic environment is a challenge that BT has addressed by automating its work management processes within a single application known as Work Manager. For the most part, the success of Work Manager rests upon the ability of its work allocation component in determining the best assignments at any time and in any environment.This paper presents a scheduler for Work Manager which is both predictive and reactive and whose computational model reconciles genericity and efficiency. Coupling Constraint Satisfaction and Local Search, this scheduler can generate long-term schedules that satisfy the conflicting objectives of feasibility, productivity, quality of service and cost minimisation. It also provides the capability to adjust schedules before despatch through on-line heuristic repair/improvement. Equipped with a powerful interface, this system has been successfully trialled within the field and is now deployed nationally.     

Field workforce scheduling

BT employs thousands of field engineers across the UK to maintain networks, repair faults and provide service to customers. To allocate work more efficiently, BT launched Work Manager in the early 1990s — an information system automating work management and field communications, and now marketed as a.p.solve's TASKFORCE. In 1996, BT Exact's Intelligent Systems Lab enhanced Work Manager with a Dynamic Scheduler (DS) combining heuristic search and constraint-based reasoning. Since its national roll-out in 1997, DS has consistently reduced operational costs while preserving high quality of service. This paper gives an overview of BT's workforce scheduling problem, the DS system, and its operational and commercial impact. This revised version was published online in July 2006 with corrections to the Cover Date.     

Natural Commutation of Current-Source Thyristor Inverters by Cage-Rotor Induction Machines

A new type of brushless cage-rotor induction machine has recently been developed [1]-[3] which is capable of providing enough counter electromotive force (EMF) when interfaced with a current-source inverter (CSI) to naturally commutate the thyristors in a high-voltage dc-link adjustable-frequency converter. The basis of this system is that by stator electromagnetic design, the induction motor may have the terminal characteristics of a dc-field synchronous machine yet still retain the torque and constructional features of a conventional induction machine. Four-quadrant operation has been demonstrated on 35- and 150-hp cage motors, and most important, leading power factor operation of the entire unit at full load is compatible with high power natural commutation of thyristor inverters. The single rotating machine has two distinct and different stator pole-pitches which must be excited from a common CSI. The analysis determines the magnitude of the CEMF available from the asynchronous condenser winding and the consequent operation of the machine in both natural commutation and in a dc-link current pulsing mode for startup.     

Development of an Induction Machine Commutated Thyristor Inverter for Traction Drives

Several designs detailing the construction of brushless cage-rotor induction machines operating at unity or leading power factor at the 35-hp level have recently been published [1]-[3]. The experimental machine combines the torque characteristics of a conventional cage induction machine with the leading power-factor (PF) capability of an overexcited dc field synchronous condenser into one unit using a common cage rotor and a common stator core. The ability of this machine to naturally commutate a high-power current-source thyristor inverter is apparent without any need for capacitors. The preferred adjustable speed propulsion arrangement consists of a mains-fed phase-delay-rectifier (PDR), high-voltage dc link, and a current-source inverter powering a ten-pole traction motor with constant V/Hz control. The drive system provides continuously variable torque during motoring, and regenerative braking modes and specific details are given for a 150-hp cage-rotor traction motor and converter, capable of natural commutation up to 200 Hz, currently under development.     

Invention before Adam and Eve

Many of man's discoveries and their applications have been anticipated by the so-called `lower orders' of living creature. This article gives some examples and the author suggests that the artificial division between engineering and biology has been a hindrance to our progress which should not be allowed to continue. In particular the author discusses nature's engineering, mathematics in nature, and electricity in nature     

The way ahead [EM launchers]

The author discusses the history and future of electromagnetic launchers, focusing on linear induction machines for producing standstill forces, for propelling high-speed vehicles, and as accelerators for producing kinetic energy. He refers to his own experience to illustrate the points made. Conclusions concerning fruitful directions for future research are drawn