The Chaotic Long-term X-ray Variability of 4U 1705-44.

The low-mass X-ray binary 4U1705-44 exhibits dramatic long-term X-ray time variability with a timescale of several hundred days. The All-Sky Monitor (ASM) aboard the Rossi X-ray Timing Explorer (RXTE) and the Japanese Monitor of All-sky X-ray Image (MAXI) aboard the International Space Station together have continuously observed the source from December 1995 through May 2014. The combined ASM-MAXI data provide a continuous time series over fifty times the length of the timescale of interest. Topological analysis can help us identify fingerprints in the phase-space of a system unique to its equations of motion. The Birman-Williams theorem postulates that if such fingerprints are the same between two systems, then their equations of motion must be closely related. The phase-space embedding of the source light curve shows a strong resemblance to the double-welled nonlinear Duffing oscillator. We explore a range of parameters for which the Duffing oscillator closely mirrors the time evolution of 4U1705-44. We extract low period, unstable periodic orbits from the 4U1705-44 and Duffing time series and compare their topological information. The Duffing and 4U1705-44 topological properties are identical, providing strong evidence that they share the same underlying template. This suggests that we can look to the Duffing equation to help guide the development of a physical model to describe the long-term X-ray variability of this and other similarly behaved X-ray binary systems.

Medical technology horizon scanning.

Horizon scanning is becoming particularly important in the medical industry, in the identification and evaluation of emerging technologies. This paper examines the role biomedical engineers may have in horizon scanning new medical technologies and considers whether this is a useful activity for biomedical engineers. A horizon scanning methodology for conducting studies of emerging medical technologies is introduced, consisting of the three main phases of (a) a systematic literature review, in which a set approach is taken to the gathering of information; (b) scanning for publications across a range of different sources; and (c) consideration of the literature in relation to fixed benchmarks to indicate the quality of published information and reported achievements. This methodology has been successfully applied by the authors in a horizon scanning study for the purpose of advising a Government agency on the status of remote patient monitoring technology.

Uptake of zinc by human placental microvillus border membranes and characterization of the effects of cadmium on this process.

The uptake of Zinc (Zn) by microvillus border membrane vesicles formed from the trophoblast of term human placentae is markedly increased over brief periods of incubation with much slower increases persisting for up to 2 h of incubation. Zinc is both bound to membrane components and transported into intravesicular osmotically active space. Uptake is saturable, temperature dependent from 4 to 37 degrees C with a Q10 of 1.7, and is inhibited by the sulphydryl agent DTNB. About 20 per cent of the uptake is susceptible to inhibition by Cadmium (Cd) at concentrations from 5 to 50 microM, a significant part of the action of this metal being on the transmembrane component of Zn uptake.

Chronic airflow obstruction in long-term survivors of allogeneic bone marrow transplantation.

Prospective pulmonary function tests (PFTs) of 49 long-term survivors of identical sibling bone marrow transplants (BMT) were analysed. Eight (16%) developed a persistent pulmonary syndrome characterised by a late onset, cough and dyspnoea, hyperinflation or patchy infiltrates on plain radiography and episodic bacterial infections. The predominant PFT pattern was obstructive (reduced forced expiratory ratio, FER) with a variable restrictive component (reduced vital capacity, VC). When compared with the other 41 patients (controls), mean FER (53% absolute) and VC (73% predicted) were significantly lower at 12 months (P = 0.005). Graft-versus-host disease (GVHD) was the only identifiable risk factor (odds ration 7.1). Five of 7 patients compared with 4 of 31 controls tested at 3 months had an abnormal FER or maximum mid-expiratory flow rate (MMFR), but not VC, prior to the onset of symptoms (P = 0.015). Patients with mild to moderate disease (FER 50-70%) had stable pulmonary function while severe cases progressed despite immunosuppressive agents. Earlier recognition of this syndrome by a reduced FER or MMFR may allow the initiation of therapy at a potentially reversible stage.

Symbolic decision support in medical care.

Symbolic decision procedures offer a flexible alternative to classical quantitative procedures for decision making, particularly when precise parameters (such as probabilities) are hard to estimate. One such procedure, based on a logic of argumentation, is described. Specifications of inference methods for such functions as proposing and refining decision options, deducing and inheriting arguments for and against options, and selecting among alternatives are presented. These exploit declarative models for patient data, domain and task knowledge. A simple method for translating the specifications into executable Prolog is described. A practical and efficient toolset for using the procedure in a wide range of clinical environments is being developed within the DILEMMA project of the European Commission's Advanced Informatics in Medicine research programme.

DILEMMA: logic engineering in primary care, shared care and oncology (AIM Project A2005).

The aim of DILEMMA is to provide tools for the development of decision support systems for use in general medical practice, hospital-based cancer care, and shared care of cancer and cardiology patients. In primary care, the project intends to provide aids to clinical performance in prescribing, referral and the use of clinical guidelines. The demonstrator applications involve telematics and knowledge-based methodology, using an approach termed logic engineering which combines logic programming and software lifecycle methods. DILEMMA will demonstrate systems to assist shared care and home care which should help reduce pressure on secondary health resources and, by disseminating best practice knowledge, improve patient care and patient quality of life.

Protocols for clinical care.

This paper describes the work of the DILEMMA project to provide protocol-based decision support in a variety of clinical domains. We give an outline of the generic protocol model that DILEMMA has produced, and the protocol task manager (PTM) software developed to assist protocol use in routine clinical practice. We summarise the validation of the model carried out to date, and take a quick look at the place of protocols in the wider context of clinical decision support.

Randomized controlled pilot trial of a hand-held patient-oriented, insulin regimen optimizer.

A robust, hand-held, patient-oriented insulin regimen optimizer (POIRO) has been developed. Relevant information is entered by selecting appropriate items from choices displayed on a touch-sensitive screen rather than a conventional keyboard. All data items are recorded, together with their time and date of entry, and may be recalled at any time with glucose values displayed graphically to provide an overview of glycaemic control. When requested, an integral, hybrid, statistical and rule-based expert system program uses all available data to suggest an optimum insulin dose within physician determined, pre-set limits. POIRO has been formally evaluated in a randomized crossover pilot trial, comparing two 3 week periods with and without decision support, in six patients with type 1 diabetes. Mean (SE) pre-prandial blood glucose levels were significantly lower during the period when decision support was available (7.5 (0.4) versus 8.9 (0.4) mmol/l, p = 0.015) with no increase in the frequency or severity of hypoglycaemia. The device, which was well received by the patients, may offer a relatively inexpensive method of providing expert diabetic advice at a distance. The persistence of improved glycaemic control, even after decision support was switched off, suggests the device could be used intermittently by patients and may have educational value.