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PubMedDate not supplied

Design for user efficiency in a dedicated ICU viewing station.

The intensive care unit (ICU) is one application where significant benefit is expected from the use of digital technology in the acquisition, management and presentation of images. However, the potential benefits should not be outweighed by disadvantages of current digital technology. One of the bottlenecks is the efficiency of image viewing using a workstation, especially if this viewing station is implemented using affordable commonly available hardware. In this paper we describe the design concepts of a relatively low-cost but efficient viewing station for chest images, and discuss clinical experience with this system at an ICU ward. The user interface has been optimized towards the specific patterns of ICU image viewing. By anticipating user requests and preparing images during idle times of the computer, the mean image access time could be reduced by a factor of 4, while most images could be presented instantaneously. Information from the hospital information system (HIS) is exploited in the user interface, and a simplified PAC-HIS coupling has been implemented for the simultaneous presentation of images and reports.

Belgium↗

PubMed2005

A method for deriving displacement data during cyclical movement using an inertial sensor.

Biomechanical studies often employ optical motion capture systems for the determination of the position of an object in a room-based coordinate system. This is not ideal for many types of study in locomotion since only a few strides may be collected per ;trial', and outdoor experiments are difficult with some systems. Here, we report and evaluate a novel approach that enables the user to determine linear displacements of a proprietary orientation sensor during cyclical movement. This makes experiments outside the constraints of the laboratory possible, for example to measure mechanical energy fluctuations of the centre of mass during over-ground locomotion. Commercial orientation sensors based on inertial sensing are small and lightweight and provide a theoretical framework for determining position from acceleration. In practice, the integration process is difficult to implement because of integration errors, integration constants and the necessity to determine the orientation of the measured accelerations. Here, by working within the constraints of cyclical movements, we report and evaluate a method for determining orientation and relative position using a modified version of a commercial inertial orientation sensor that combines accelerometers, gyroscopes and magnetometers, thus giving a full set of movement parameters (displacement, velocity and acceleration in three dimensions). The 35 g sensor was attached over the spine of a horse exercising on a treadmill. During canter locomotion (9.0 m s-1), the amplitudes of trunk movement in the x (craniocaudal), y (mediolateral) and z (dorsoventral) directions were 99.6, 57.9 and 140.2 mm, respectively. Comparing sensor displacement values with optical motion capture values for individual strides, the sensor had a median error (25th, 75th percentile) in the x, y and z directions of 0.1 (-9.7, +10.8), -3.8 (-15.5, +13.7) and -0.1 (-6.3, +7.1) mm, respectively. High-pass filtering of the displacement data effectively separated non-cyclical from cyclical components of the movement and reduced the interquartile ranges of the errors considerably to (-3.6, 6.2), (-4.0, 3.8) and (-4.5, 5.1) for x, y and z displacement, respectively, during canter locomotion. This corresponds to (-3.2, 5.5)%, (-6.7, 6.3)% and (-3.3, 3.7)% of the range of motion.

Acceleration↗

PubMed2001

Observation and experiment with the efficacy of drugs: a warning example from a cohort of nonsteroidal anti-inflammatory and ulcer-healing drug users.

Observational data are well suited for many types of medical research, especially when randomized controlled trials are inappropriate. However, some researchers have attempted to justify routine use of observational data in situations in which randomized controlled trials are normally conducted. Literature searches cannot be used to directly compare the results of the two types of research, because invalid observational studies normally are not publishable in the journal literature. The author created a study (1989-1994) to determine the efficacy of one exposure (ulcer-healing drugs) in preventing the serious upper gastrointestinal toxicity associated with another exposure (nonsteroidal anti-inflammatory drugs (NSAIDs)). A cohort of subjects from Tayside, Scotland, receiving both NSAIDs and ulcer-healing drugs appeared to experience a large rise in their risk of gastric bleeding and perforation (e.g., the rate ratio was 10.00 (95% confidence interval: 6.68, 14.97) when this cohort was compared with one receiving NSAIDs alone). This increased risk was due to confounding. Thus, use of a "restricted cohort design" was not able to eliminate uncontrollable bias. It is possible that if many different studies were carried out, then observational research would be found to be only occasionally useful for studying drug efficacy.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Use of an interactive tool to assess patients' willingness-to-pay.

Assessment of willingness to pay (WTP) has become an important issue in health care technology assessment and in providing insight into the risks and benefits of treatment options. We have accordingly explored the use of an interactive method for assessment of WTP. To illustrate our methodology, we describe the development and testing of an interactive tool to administer a WTP survey in a dental setting. The tool was developed to measure patient preference and strength of preference for three dental anesthetic options in a research setting. It delivered written and verbal formats simultaneously, including information about the risks and benefits of treatment options, insurance, and user-based WTP scenarios and questions on previous dental experience. Clinical information was presented using a modified decision aid. Subjects could request additional clinical information and review this information throughout the survey. Information and question algorithms were individualized, depending on the subject's reported clinical status and previous responses. Initial pretesting resulted in substantial modifications to the initial tool: shortening the clinical information (by making more of it optional reading) and personalizing the text to more fully engage the user. In terms of results 196 general population subjects were recruited using random-digit dialing in southwestern Ontario, Canada. Comprehension was tested to ensure the instrument clearly conveyed the clinical information; the average score was 97%. Subjects rated the instrument as easy/very easy to use (99%), interesting/very interesting (91%), and neither long nor short (72.4%). Most subjects were comfortable/very comfortable with a computer (84%). Indirect evaluation revealed most subjects completed the survey in the expected time (30 min). Additional information was requested by 50% of subjects, an average of 2.9 times each. Most subjects wanted this type of information available in the provider's office for use in clinical decision making (92%). Despite extensive pretesting, three "bugs" remained undiscovered until live use. We have demonstrated that the detailed information, complex algorithms, and cognitively challenging questions involved in a WTP survey can be successfully administered using a tailor-made, patient-based, interactive computer tool. Key lessons regarding the use of such tools include allowing the user to set the pace of information flow and tailor the content, engaging the user by personalizing the textual information, inclusion of tests of comprehension and offering opportunities for correction, and pretesting by fully mimicking the live environment.

Adult↗

PubMed1991

A fast 80X86 assembly language module to low-pass filter digital data.

This short assembly language procedure, which can be called from a high level language program, will low-pass filter an array of digital data. This is a well known algorithm coded in assembly language for speed: it filters 512 data points in 5 ms in a 16 MHz 386 microcomputer. The procedure can handle up to 32 kb of binary data, 12-16 bits wide, from an on-line experiment or from an already stored file. The user chooses the cutoff frequency selecting a factor and how many times the data are passed through the filter. The filter has an excellent time-domain response which makes it ideal for physiological pulse recording. The listings of the source assembly routine and of a sample Pascal program that calls it are provided in the text.

Algorithms↗

PubMed1990

Functionality of the ARPIA ambulatory information system.

Although database-based medical information systems are becoming popular, experiments done by researchers tell us that physicians still do not fully accept them. Key factors for changing physicians' practice habits are the availability of more powerful methods and tools for interactive data acquisition and retrieval. Problems involving human engineering usually require the identification of and experimentation with many novel approaches before the most suitable answer is discovered. ARPIA is an ambulatory information system experimenting on the effectiveness and acceptability (by medical users) of new intelligent and friendly interaction techniques and tools. In particular, it tests a novel flexible dialogue-based man-machine interface offering physical and logical data 'independence' during retrieval operations. Other features of the system are: a fast and robust data acquisition environment; a text- and picture-based data presentation and report generation facility; finally, a set of modules offering the ambulatory staff effective assistance in some extra complex interactive tasks. A user-oriented description of the main functionality of ARPIA is given; users' feedback summarizing almost 2 years of usage of the system is also reported.

Ambulatory Care Information Systems↗

PubMed2004

Acute reduction in secretory immunoglobulin A following smoking cessation.

Smokers report an increase in upper respiratory infections in the early phase of stopping smoking. One possible cause is a depletion in secretory immunoglobulin A (S-IgA) which has been observed in one study. The present study sought to establish this finding in smokers using nicotine patches. Ninety-two smokers, trying to stop smoking, were assessed whilst smoking and for up to six weeks of abstinence. All smokers were prescribed 15 mg 16-h nicotine patches. Among abstinent smokers, changes in S-IgA and saliva volume were assessed. During the preliminary analyses, we observed that for the pre-smoking cessation measure a longer time since the last cigarette was significantly related to lower S-IgA levels (P = 0.006). Consequently, the main analysis, of changes in S-IgA from pre-cessation to post-cessation, was confined to those who had smoked within 0.5-1.5 h of the pre-cessation measure (n = 51). There was a significant decline in S-IgA, relative to pre-smoking abstinence levels, following abstinence of one day (P = 0.027), but levels returned to pre-abstinence values after one week. There was no evidence of any significant changes in saliva volume following smoking cessation, relative to pre-cessation levels. Users of 15 mg patches are likely to experience a decline in S-IgA levels on the first day of smoking cessation, independent of saliva volumes, and this decline in S-IgA is likely to occur acutely, within the first few hours of smoking abstinence. This acute drop in S-IgA appears to stem from a factor other than depletion of nicotine from the body. The observed decrease in S-IgA may help to explain the increased susceptibility of smokers to upper respiratory tract infections in the immediate post-cessation period.

Administration, Cutaneous↗

PubMed2002

Visual product evaluation: exploring users' emotional relationships with products.

This paper discusses an industrial designer's approach to eliciting user perceptions and emotional responses to products through visual evaluation and stimuli. Whilst the authors accept that product functionality is crucial for product success, the appearance, use of materials, shape and form provide the most immediate product data for the user. Less tangible issues such as emotional bonding of users with products, cultural perceptions and social value systems, provide valuable insights for the product developer to help expand knowledge and understanding of the users' need beyond the functional. This paper presents product personality profiling as a new technique for design researchers/designers, and discusses it alongside other emerging approaches such as mood boards and visual product evaluation. The authors have used these techniques during focus group sessions with users to elicit individuals' needs and aspirations towards products. Such a user-centred approach is fundamental to applied ergonomics. Experiences, benefits, and limitations of these techniques are outlined as well as the opportunities for further development.

Emotions↗

PubMed1999

The World Health Organization multinational study of breast-feeding and lactational amenorrhea. IV. Postpartum bleeding and lochia in breast-feeding women. World Health Organization Task Force on Methods for the Natural Regulation of Fertility.

OBJECTIVE: To describe and compare the duration of lochia in seven groups of women; to investigate the occurrence of a possible "end-of-puerperium" bleeding episode; and to determine the frequency of bleeding episodes before postpartum day 56, which applies to the practice of the lactational amenorrhea method of contraception. DESIGN: Prospective longitudinal study with fortnightly follow-up, beginning within 7 days of delivery. SETTING: Five developing and two developed countries. PATIENT(S): Four thousand one hundred eighteen breast-feeding women. INTERVENTION(S): Postpartum lochia and all days of bleeding per vaginam were recorded. MAIN OUTCOME MEASURE(S): Duration of lochia, frequency of an end-of-puerperium bleeding episode, and frequency of postlochia bleeding episodes within 56 days of delivery. RESULT(S): The median duration of lochia was 27 days; it varied significantly among the centers (range, 22-34 days). In 11% of the women, lochia lasted >40 days. An end-of-puerperium bleeding episode around the 40th day postpartum was reported by 20.3% of the women. Bleeding within 56 days of delivery (separated from lochia by at least 14 days) occurred in 11.3% of the women and usually was followed by a confirmatory bleeding episode 21-70 days later. CONCLUSION(S): The duration of lochia varied significantly among the study populations, and long durations were not unusual. The significance of the end-of-puerperium bleeding episode is unknown. Most users of the lactational amenorrhea method will not experience a postlochia bleeding episode before postpartum day 56.

Amenorrhea↗

PubMed1999

Mechanistic bases for adverse vaccine reactions and vaccine failures.

Mild local and systemic reactions to vaccines are to be expected as a natural consequence of vigorously stimulating the immune system. Dramatic adverse reactions to vaccines are occasionally due to mistakes during the production or handling of vaccines. More often, they are due to not following label instructions, particularly the restriction to only use vaccines in healthy animals. It is important to publish well-documented instances of adverse vaccine reactions so that producers and users of vaccines can all learn from the experience and avoid similar problems. Vaccine failure to protect from disease is usually due to problems with either client education or compliance with good animal management practices. It is important for clients to understand the proper timing and method of vaccine administration, what to realistically expect for vaccine efficacy, and the importance of minimizing immunosuppressive factors and exposure to high doses of infectious agents in vaccinated animals. Veterinary vaccines have produced dramatic benefits in terms of animal health, human health, and efficiency of food production. Advances in research and the accumulating experience with vaccines are leading to safer and more effective vaccines. Proper usage of vaccines and adherence to good management practices will continue to be essential to achieve maximal vaccine safety and efficacy.

Animal Husbandry↗

PubMed2001

An imaging system for monitoring receptive field dynamics.

The paper describes a computerized method, termed receptive field imaging (RFI), for the rapid mapping of multiple receptive fields and their respective sensitivity distributions. RFI uses random stimulation of multiple sites, in combination with an averaging procedure, to extract the relative contribution from each of the stimulated sites. Automated multi-electrode stimulation and recording, with spike detection and counting, are performed on-line by the RFI programme. Direct user interpretation of receptive field changes is made possible by a user-friendly graphic interface. A series of imaging experiments was carried out to evaluate the functional capacity of the system. RFI was tested on the receptive fields in the nociceptive withdrawal reflex (NWR) system in the rat. RFI replicates the results obtained with conventional methods and allows the display of receptive field dynamics induced by topical spinal cord application of morphine and naloxone on a minute-to-minute time scale. Data variance was estimated, and proved to be small enough to yield a stable representation of the receptive field, thereby achieving a high sensitivity in dynamic imaging experiments. The large number of stimulation and registration sites that can be monitored in parallel permits detailed network analysis of synaptic sets, corresponding to 'connection weights' between individual neurones.

Analysis of Variance↗

PubMed2001

Transmission electron microscopy with Zernike phase plate.

The possibility of implementing a Zernike phase plate in a transmission electron microscope is investigated both theoretically and experimentally. The phase-retarding plate in the form of thin film with a hole in the center is positioned in the back-focal plane of the objective lens. The experiments show that the phase plate functions as predicted, producing a cosine-type phase contrast transfer function. Images of negatively stained horse spleen ferritin were highly improved in the contrast and the image-modulation, compared to those acquired without the phase plate. Charging and related difficulties were encountered during the phase plate experiments. In order to make the technique user-friendly a number of improvements have to be made, and are discussed in terms of the current level of technology and instrumentation.

Animals↗

PubMed1999

Dimensional change in muscle as a control signal for powered upper limb prostheses: a pilot study.

The vast majority of externally powered prostheses are controlled from the myoelectric signal, measured at the skin surface using socket-located electrodes. This signal has been well researched and sophisticated signal processing methods developed. Nevertheless, the inherent properties of the signal, such as its broad bandwidth and low voltage amplitude, make its use less than straightforward in the control of low frequency activity such as powered prosthetic hand movement. This paper reports on a pilot study of an alternative, a signal derived from dimensional change in muscle. A new socket-located sensor was designed to measure dimensional change in muscle, the linearised output of which is termed the myokinemetric (MK) signal. This was used in a series of tasks aimed at investigating the potential for its use in upper-limb prosthesis control. Six amputee subjects were tested, of whom one was a regular user of the myoelectric hand, one had some experience, and four had little or no previous experience of controlling devices using their residual limb. Data is presented on the problems of shift in signal range with time and socket donning and doffing and on the ability of subjects to control the amplitude of the signal. The results show that subjects were able to control the magnitude of the MK signal to a significant degree, with typical errors averaging 0.1-0.3 mm, around 10% of the signal range. The principal problem encountered was the shift in signal with time and socket donning and doffing.

Adult↗

PubMedDate not supplied

An e-science environment for service crystallography--from submission to dissemination.

The U.K. National Crystallography Service (NCS) has developed a prototype e-science infrastructure for the provision of a small molecule crystallography service from sample receipt to results dissemination. This paper outlines the two strands of this service, which (a) enable a user to contribute in the conduction of an experiment and (b) provide an effective route for the archival and dissemination of the arising results. Access to use the NCS facilities and expertise and a mechanism to submit samples is granted through a secure Grid infrastructure, which seamlessly provides instantaneous feedback and the ability to remotely monitor and guide diffraction experiments and stage the diffraction data to a securely accessible location. Publication of all the data and results generated during the course of the experiment, from processed data to analyzed structures, is then enabled by means of an open access data repository. The repository publishes its content through established digital libraries' protocols, which enable harvester and aggregator services to make the data searchable and accessible.

Crystallography, X-Ray↗

PubMed2002

A multidimensional scaling analysis of tone discrimination ability in Cantonese-speaking children using a cochlear implant.

Tone discrimination testing with two groups of profoundly hearing-impaired children using a cochlear implant and one group of normally hearing children suggests that pitch level is perceptually more salient than pitch contour. In this paper, the discrimination results from these children are submitted to a multidimensional scaling analysis to determine what differences if any exist between the children in the information they use to discriminate between tone types. Through the multidimensional scaling analysis it is shown that, 'average pitch height' and 'pitch direction' are the most salient acoustic features in tone with pitch height being perceptually more important than pitch level. Furthermore, these acoustic features are similarly salient for all three groups of children despite differences in the source of auditory information and linguistic experience. Finally, the two groups of cochlear implant users who employ different speech processing strategies with their implant are shown to be distinguishable by differences in the relative salience of pitch direction.

Child↗

PubMedDate not supplied

Drug treatment on demand--not.

Drug treatment on demand, appropriate and affordable drug treatment for injection drug users who are "ready" to enter a program, is a humane approach to drug treatment services and an important mechanism to halt the spread of HIV. However, drug treatment on demand is not a reality in the United States. In fact, due to funding cuts at federal, state, and local levels, entry into drug treatment programs has become increasingly more difficult over the past decade. In a NIDA-funded ethnographic study of methadone maintenance, i.v. drug use and AIDS, 70 heroin addicts who were out of treatment and actively seeking methadone maintenance were interviewed. In life-history interviews, the drug users described barriers to treatment, waiting-list experiences, and the impact of these experiences on their drug use, drug-using behavior, and emotional well-being. Respondents used many mechanisms to cope with the lack of availability of drug treatment slots, some of which have increased their risk of exposure to and spread of HIV. These findings indicate the need for an increase in the availability of subsidized methadone maintenance treatment slots "on demand" if individuals are to decrease their drug use and their high-risk behaviors. Drug treatment on demand is more than politically correct rhetoric. It is a necessary ingredient in reducing the harm caused by the use of illegal drugs.

Adaptation, Psychological↗

PubMed2003

Pelvic motion in trans-femoral amputees in the frontal and transverse plane before and after special gait re-education.

Using a special gait re-education programme, combining methods in physiotherapy with a psychological therapeutic approach to integrate the prosthesis with normal movements and to increase body awareness, the authors studied unilateral trans-femoral amputees aged 16-60 years with trauma or tumour as causes. In their service area they found 16 such current prosthetic users with at least 2 years of prosthetic experience and 9 who could complete the programme. Gait was measured before and after treatment and at 6 months follow-up with a three-dimensional motion analysis system and was compared to a reference group of 18 healthy volunteers of similar age. Results showed normalised gait speed and increased symmetry in step length after treatment, but reduced symmetry in pelvic motion. The reference group had a pelvic rotation of + 4 degrees both in the frontal and transverse planes. In the frontal plane, pelvic obliquity increased after treatment to a similar amplitude to the reference group, but with a different timing. Pelvic internal rotation on the amputated side increased to about 8 degrees in the beginning of stance. The amputated and the intact side before treatment were more symmetrical than afterwards and also when compared with the reference group. In spite of this, gait appeared to be more symmetrical, probably due to more efficient pelvic motion and more symmetrical upper-body movements. This was probably an effect of increased work with the intact side to compensate for the lack of power on the amputated side. These results remained at follow-up.

Adolescent↗

PubMed2002

Drug use, travel and HIV risk.

A study was conducted to examine the travel experiences of a community sample of 160 drug users and 44 non-users recruited as part of a study of HIV risk. Of the sample, 47% (96/204) reported intercity travel in the previous ten years. Results showed that men were more likely to travel than women, Anglos more than minorities, and young persons more than old. When travellers testing HIV-seropositive (n = 13) were compared with seronegative travellers, HIV-positive travellers reported more sex while travelling than HIV-negative persons, but virtually all of the difference reported involved sex with condoms. There were no significant differences in sex risk behaviours while travelling between drug users and non-drug users, or in sex risk behaviors between drug injectors and non-injectors. Travellers had fewer injection partners while travelling than they had while at home. There was also a significant difference in number of sex partners with whom a condom was not used, with fewer sex partners while travelling.

Adult↗