The history of wireless power transmission

The history of wireless power transmission at microwave frequencies is reviewed with emphasis upon the time period starting with the post World War II efforts to use the new microwave technology developed during the war. A nationally televised demonstration of a microwave powered helicopter at the Spencer Laboratory of the Raytheon Co., in 1964 was the result of these early efforts and broadly introduced the concept of wireless power transmission to scientific and engineering communities and to the public. Subsequent development efforts centered on improving the efficiency of the interconversion of d.c. and microwave power at the ends of the system to reach a demonstrated overall d.c. to d.c. system efficiency of 54% in 1974. The response to the requirements of applications such as the Solar Power Satellite and high altitude microwave powered aircraft have changed the direction of technology development and greatly expanded the technology base. Recent and current efforts are centered on examining the use of higher frequencies than the baseline 2.45 GHz, and in reducing the system costs at 2.45 GHz.     

Implementing Information Systems: Some Practical Advice and a Richer Model

Recent research suggests that implementing information systems presents considerable difficulties and that many implementations are total or partial failures. This paper argues that what both practitioners and students require are richer and more acceptable models of information systems implementation. Accordingly, case study data concerning the introduction of manufacturing resource planning (MRP II) are used to illustrate five patterns of behaviour (rites) which capture important social actions; and four components of changing psychological orientation. It is argued that appreciation of the rites and psychological developments identified here will support effective change programmes. Guidelines based on our model are provided for practitioners.     

A monoclonal antibody selected for probing the folding of staphylococcal nuclease and its N-terminal fragments

PURPOSE: Nitric oxide (NO) is generated in mammalian tissue by the conversion of L-arginine to L-citrulline. The reaction is catalyzed by nitric oxide synthase (NOS). NO has been suggested to have a dual role in tumor biology with both antitumor and tumor promoter activity. Furthermore, it has been proposed that NO contributes to interleukin-2-induced antitumor activity. Since interleukin-2 is used in the treatment of renal cell carcinoma (RCC) it was of interest to study the NOS activity in the human kidney and in RCC and its correlation to tumor grade. Furthermore, the effect of cytokine treatment on NOS activity and the effect of NO donor application was studied in cultured cells. MATERIALS AND METHODS: The effect of cytokine treatment on NOS activity and the effect of NO donor application on cell proliferation was studied in cultured human proximal tubular cells and in RCC cell lines HN4 and HN51. NOS activity was measured by the L-arginine to L-citrulline conversion assay. RESULTS: Calcium-dependent NOS activity was found in all non-malignant kidney tissues (486+/-63 pmol. min(-1) g(-1) tissue). The activity was significantly lower in RCC (24+/-6 pmol. min(-1) g(-1) tissue) and correlated with tumor grade; thus high grade tumors showed lower activity than low grade tumors. Calcium-independent NOS activity was not detected in non-malignant kidney tissue or in RCC tissue. In cultured proximal tubular cells and RCC cell lines HN4 and HN51, cytokine treatment induced a marked increase in NOS activity and NO exerted cytostatic effects on these cell lines. Conclusions: The NOS activity was higher in non-malignant kidney tissue than in RCC tissue and was inversely correlated with tumor grade. Furthermore, cytokine treatment induced a marked increase in NOS activity and NO exerted cytostatic effects on cultured proximal tubular cells and RCC cell lines.     

TraceLink: a model of amnesia and consolidation of memory

This investigation examined the feasibility of applying the conductance catheter technique for measurement of absolute aortic segmental volume. Aortic segment volume was estimated simultaneously in vitro by using the conductance catheter technique and sonomicrometer crystals. Experiments were performed in five isolated canine aortas. Vessel diameter and pressure were altered, as were the conductive properties of the surrounding medium. In addition, a three-dimensional finite-element model of the vessel and apparatus was developed to examine the electric field and parallel conductance volume under different experimental conditions. The results indicated that in the absence of parallel conductance volume, the conductance catheter technique predicted absolute changes in segmental volumes and segmental pressure-volume relationships that agreed closely with those determined by sonomicrometry. The introduction of parallel conductance volume added a significant offset error to measurements of volume made with the conductance catheter that were nonlinearly related to the conductive properties of the surrounding medium. The finite-element model was able to predict measured resistance and parallel conductance volume, which correlated strongly with those measured in vitro. The results imply that absolute segmental volume and distensibility may be determined only if the parallel conductance volume is known. If the offset volume is not known precisely, the conductance catheter technique may still be applied to measure absolute changes in aortic segmental volume and compliance.     

Resistance to atracurium in rats with experimental inflammation: role of protein binding

The influence of altered protein binding on the neuromuscular effect of atracurium has been studied in rats with experimental inflammation induced by subcutaneous injection of turpentine oil. Doses of atracurium ranging from 0.45 to 1.5 mg.kg-1 were administered to control (n = 30) and to experimental inflammation induced rats (n = 30). Neuromuscular transmission was monitored by recording the twitch tension of the tibialis-anterior muscle elicited by stimulation of the sciatic nerve. Three effect parameters were recorded: (i) intensity of the effect, measured as percentage depression of baseline twitch tension, (ii) duration of drug action (min) and (iii) recovery time (min). The dose-intensity of the effect relationship was modelled using a sigmoid Emax model. The ED50 (effective dose eliciting 50% of the maximum effect) was significantly increased (P < 0.01) in the inflammation group as compared to the control group (0.94 vs. 0.68 mg.kg-1). This change was reflected in a shift of the dose-response curve to the right in the pretreated rats. For equipotent doses ED95 (defined as the effective dose eliciting 95% of maximum effect), no differences were found in recovery time and duration of action between the two groups of rats. Mucoproteins levels (index of alpha 1-acid glycoprotein (AAG) and protein binding were significantly increased in rats with experimental inflammation as compared to control rats. Based on these results, altered serum protein binding of atracurium appears to be responsible, at least in part, for the resistance to atracurium.     

Developing visiting surgical services for rural and remote Australian communities

The University Department of Surgery at Queen Elizabeth II Medical Centre (Perth, Western Australia) has undertaken a pilot project to provide surgical services to country communities where no such service exists. Three surgeons undertake a regular schedule of appointments, and are accompanied by final-year medical students to give them experience with common conditions rarely managed in teaching hospitals. The service is supported by a central administrative office and coordinated by a general practitioner, who negotiates with the regional healthcare providers. Patients are referred by their general practitioner, who may work with the surgeon as anaesthetist or surgical assistant.     

Traumatic myocardial infarction caused by lead shot

The authors report the case of a 32 year old woman who was shot with a shotgun. Acute inferior wall infarction was detected fortuitously on electrocardiography and coronary angiography showed occlusion of the right coronary artery with lead shot. The single coronary lesion, absence, of other cardiac complications (haemopericardium, cardiac perforation, ...) and the favourable outcome with conservative medical treatment has not been previously reported to the authors' knowledge.