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Biomedical subjects

A M Williams

Publications and source records attributed to A M Williams.

At least 19 recordsLinked to original sources
PubMed2006

The meniscal flounce: a valuable arthroscopic sign.

PURPOSE: The purpose of this study was to characterise the incidence and significance of the meniscal flounce. TYPE OF STUDY: Prospective Cohort Study. METHOD: A prospective study of 1088 consecutive knee arthroscopies. RESULTS: Intact menisci tended to have a flounce of characteristic size and position. The presence of this 'normal' flounce was closely correlated with an intact meniscus (p<0.0001). For the medial meniscus with a small flounce in zone 3 the sensitivity, specificity, and positive predictive value (PPV) for an intact medial meniscus were 68.5%; 92.9%; and 92.1% respectively. Conversely the presence of meniscal pathology correlated closely with either an absent or abnormal flounce (p<0.0001). The absence of a medial flounce had sensitivity, specificity, and PPV for a meniscal tear of 82.8%; 84.9%; and 81.9% respectively. CONCLUSIONS: The findings of this study are useful for arthroscopists especially when there is difficulty visualising all of the posterior half of the meniscus. In this situation the presence of a normal flounce is likely to signify an intact meniscus. However the presence of an abnormal or absent flounce may be the sign of an occult meniscal tear requiring better exposure.

Adolescent↗
PubMed2005

Conflicts in the treatment of chronic ulcers in drug addicts--case series and discussion.

Vascular access in intravenous drug abusers may become compromised by the repeated injection of toxic substances. In such circumstances abusers are driven by their addiction to seek alternative routes of drug delivery. We report a series of individuals with chronic ulcers, which were cultivated and maintained for the administration of heroin. We advise that practitioners should be wary of granulation tissue being promoted in this way and suggest that the patients' desire for wound healing may be overridden by their addiction and that successful treatment of these wounds is reliant upon cessation of drug abuse and patient compliance. In our experience this is most easily achieved in a multidisciplinary environment.

Adult↗
PubMed2005

Ultrasound-assisted hydrogenation of cinnamaldehyde.

The hydrogenation, employing hydrogen gas, of cinnamaldehyde was performed using Pd-black and Raney Ni catalysts at 298+/-3 K in a water-cooled (jacketed) reaction vessel. Sampling at pre-determined time intervals and GC/MS analysis yielded time-dependent product state distribution information. A kinetic modeling of the data revealed that cinnamaldehyde was both hydrogenated directly to the final product benzenepropanol, as well as a fraction being converted to the intermediate benzenepropanal, where the latter was subsequently hydrogenated to benzenepropanol. Comparing the ultrasound-assisted and blank (stirred) experiments revealed that a higher maximum relative concentration of the intermediate benzenepropanal was formed in the ultrasound experiments compared to the stirred experiment. The activity of the ultrasound experiments compared to blank were 9-fold and 20-fold greater for the Pd-black and Raney Ni catalysts, respectively. Finally, an application of the Bell-Evans-Polanyi principle to yield an estimate of the ratio of rate coefficients for benzenepropanal and benzenepropanol formation was performed by considering chemical group energy differences and surface adsorption energy differences in the first mechanistic step of hydrogenation.

Journal Article↗
PubMed2005

Visual search and coordination changes in response to video and point-light demonstrations without KR.

The authors examined the observational learning of 24 participants whom they constrained to use the model by removing intrinsic visual knowledge of results (KR). Matched participants assigned to video (VID), point-light (PL), and no-model (CON) groups performed a soccer-chipping task in which vision was occluded at ball contact. Pre- and posttests were interspersed with alternating periods of demonstration and acquisition. The authors assessed delayed retention 2-3 days later. In support of the visual perception perspective, the participants who observed the models showed immediate and enduring changes to more closely imitate the model's relative motion. While observing the demonstration, the PL group participants were more selective in their visual search than were the VID group participants but did not perform more accurately or learn more.

Adult↗
PubMed2004

Response of a lithium gadolinium borate scintillator in monoenergetic neutron fields.

Accurate estimation of neutron dose requires knowledge of the neutron energy distribution in the working environment. Existing neutron spectrometry systems, Bonner spheres for example, are large and bulky, and require long data acquisition times. A portable system that could indicate the approximate neutron energy spectrum in a short time would be extremely useful in radiation protection. A composite scintillator, consisting of lithium gadolinium borate crystals in a plastic scintillator matrix, produced by Photogenics is being tested for this purpose. A prototype device based on this scintillator and digital pulse processing electronics has been calibrated using quasi-monoenergetic neutron fields at the low-scatter facility of the UK National Physical Laboratory (NPL). Energies selected were 144, 250, 565, 1400, 2500 and 5000 keV, with correction for scattered neutrons being made using the shadow cone technique. Measurements were also made in the NPL thermal neutron field. Pulse distributions collected with the digitiser in capture-gated mode are presented, and detection efficiency and energy resolution derived. For comparison, neutron spectra were also collected using the commercially available Microspec N-Probe from Bubble Technology Industries, which consists of an NE213 scintillator and a 3He proportional counter.

Algorithms↗
PubMed2003

Pectus deformities of the anterior chest wall.

Pectus deformities affect about 1% of the population. Despite a subjective reduction in exercise tolerance, objective physiological disturbance is very uncommon. However, there is no doubt that cultural changes have significantly altered perception and tolerance of these deformities and increasing numbers of children are actively seeking surgery. Pectus excavatum is readily amenable to correction using minimally invasive techniques and pectus carinatum can be corrected using safe established conventional techniques. Good or excellent results can be expected in over 90% of cases, and children should no longer be denied treatment.

Funnel Chest↗
PubMed2003

Modelling home advantage in the Summer Olympic Games.

Home advantage in team games is well proven and the influence of the crowd upon officials' decisions has been identified as a plausible cause. The aim of this study was to assess the significance of home advantage for five event groups selected from the Summer Olympic Games between 1896 and 1996, and put home advantage in team games in context with other sports. The five event groups were athletics and weightlifting (predominantly objectively judged), boxing and gymnastics (predominantly subjectively judged) and team games (involving subjective decisions). The proportion of points won was analysed as a binomial response variable using generalized linear interactive modelling. Preliminary exploration of the data highlighted the need to control for the proportion of competitors entered and to split the analysis pre- and post-war. Highly significant home advantage was found in event groups that were either subjectively judged or rely on subjective decisions. In contrast, little or no home advantage (and even away advantage) was observed for the two objectively judged groups. Officiating system was vital to both the existence and extent of home advantage. Our findings suggest that crowd noise has a greater influence upon officials' decisions than players' performances, as events with greater officiating input enjoyed significantly greater home advantage.

Boxing↗
PubMed2003

A prospective, randomised comparison of autologous chondrocyte implantation versus mosaicplasty for osteochondral defects in the knee.

Autologous chondrocyte implantation (ACI) and mosaicplasty are both claimed to be successful for the repair of defects of the articular cartilage of the knee but there has been no comparative study of the two methods. A total of 100 patients with a mean age of 31.3 years (16 to 49) and with a symptomatic lesion of the articular cartilage in the knee which was suitable for cartilage repair was randomised to undergo either ACI or mosaicplasty; 58 patients had ACI and 42 mosaicplasty. Most lesions were post-traumatic and the mean size of the defect was 4.66 cm2. The mean duration of symptoms was 7.2 years and the mean number of previous operations, excluding arthroscopy, was 1.5. The mean follow-up was 19 months (12 to 26). Functional assessment using the modified Cincinatti and Stanmore scores and objective clinical assessment showed that 88% had excellent or good results after ACI compared with 69% after mosaicplasty. Arthroscopy at one year demonstrated excellent or good repairs in 82% after ACI and in 34% after mosaicplasty. All five patellar mosaicplasties failed. Our prospective, randomised, clinical trial has shown significant superiority of ACI over mosaicplasty for the repair of articular defects in the knee. The results for ACI are comparable with those in other studies, but those for mosaicplasty suggest that its continued use is of dubious value.

Adolescent↗
PubMed2002

Local stability in coordinated rhythmic movements: fluctuations and relaxation times.

An experiment was conducted to examine the stability of the anti-phase and in-phase modes of coordination by means of both fluctuations and relaxation times. Participants (n=6) performed a rhythmic bimanual forearm coordination task that required them to oscillate their forearms in-phase and anti-phase while grasping two manipulanda at fixed frequencies ranging from 0.6 to 1.8 Hz. Relaxation times were measured as the time taken to return to a stable mode following the application of a transient mechanical torque. It was found that relaxation times were not different statistically across participants, frequencies, and coordinative modes. However, fluctuations, as indicated by the mean S.D. of relative phase across individual frequency plateaus, were significantly greater in the anti-phase than in the in-phase mode of coordination, p<0.05. Whilst providing new empirical support for the notion that relaxation times should be of the same order of magnitude at frequencies outside transition regions, the findings suggest that the level of stochastic noise in the anti-phase mode is greater than that of the in-phase mode. Implications are made for the future assessment of local pattern stability.

Adult↗
PubMed2001

Balancing and compromising: nurses and patients preserving integrity of self and each other.

This paper brings together the perspective of both nurses and patients of the experience of nursing care delivery in acute care hospital settings. Initially, two grounded theory studies of the phenomenon of high-quality nursing care were conducted concurrently and in the same settings; one focussed on patients' experiences (Irurita, 1993. From person to patient: nursing care from the patient's perspective. Department of Nursing Research, Sir Charles Gairdner Hospital), the other on those of nurses (Williams, 1994. Unpublished report, Department of Nursing Research Sir Charles Gairdner Hospital, Perth, Western Australia). Similarities between the findings of both studies led the authors, using grounded theory methods, to re-examine and compare the findings and raw data, with additional data collected by theoretical sampling. The previous findings were integrated and extended, resulting in the development of a theory of Balancing and Compromising in response to the shared problem of threats to integrity, especially encountered when broader environmental and contextual conditions were unfavourable. This reciprocal process used by nurses and patients to preserve their own and each other's integrity involved: contributing to care--cooperating; prioritising and rational sacrificing; justifying compromised care and lowering expectations; and protecting self by attracting or repelling. Both positive and negative outcomes resulted.

Acute Disease↗
PubMed2001

The normal position of the umbilicus in the newborn: an aid to improving the cosmetic result in exomphalos major.

BACKGROUND/PURPOSE: The aim of this study was to determine the normal position of the umbilicus and hence improve the cosmetic result of exomphalos major repair. METHODS: The position of the umbilicus was determined in 50 neonates with respect to the xiphisternum and pubis. RESULTS: The normal umbilical position is 60% of the way from the inferior border of the xiphisternum to the superior border of the pubis in the midline. CONCLUSION: In the repair of exomphalos major, the most aesthetically pleasing result is obtained if the umbilicus is placed 60% of the way from the xiphisternum to the pubis.

Esthetics↗
PubMed2001

Home advantage in the Winter Olympics (1908-1998).

We obtained indices of home advantage, based on the medals won by competing nations, for each event held at the Winter Olympics from 1908 to 1998. These indices were designed to assess home advantage while controlling for nation strength, changes in the number of medals on offer and the performance of 'non-hosting' nations. Some evidence of home advantage was found in figure skating, freestyle skiing, ski jumping, alpine skiing and short track speed skating. In contrast, little or no home advantage was observed in ice hockey, Nordic combined, Nordic skiing, bobsled, luge, biathlon or speed skating. When all events were combined, a significant home advantage was observed (P = 0.029), although no significant differences in the extent of home advantage were found between events (P > 0.05). When events were grouped according to whether they were subjectively assessed by judges, significantly greater home advantage was observed in the subjectively assessed events (P = 0.037). This was a reflection of better home performances, suggesting that judges were scoring home competitors disproportionately higher than away competitors. Familiarity with local conditions was shown to have some effect, particularly in alpine skiing, although the bobsled and luge showed little or no advantage over other events. Regression analysis showed that the number of time zones and direction of travel produced no discernible trends or differences in performance.

Female↗
PubMed2001

Transforming growth factor-beta messenger RNA and protein in murine colitis.

Using a CD4+ T-cell-transplanted SCID mouse model of colitis, we have analyzed TGF-beta transcription and translation in advanced disease. By in situ hybridization, the epithelium of both control and inflamed tissues transcribed TGF-beta1 and TGF-beta3 mRNAs, but both were expressed significantly farther along the crypt axis in disease. Control lamina propria cells transcribed little TGF-beta1 or TGF-beta3 mRNA, but in inflamed tissues many cells expressed mRNA for both isoforms. No TGF-beta2 message was detected in either control or inflamed tissues. Immunohistochemistry for latent and active TGF-beta1 showed that all cells produced perinuclear latent TGF-beta1. The epithelial cell basal latent protein resulted in only low levels of subepithelial active protein, which co-localized with collagen IV and laminin in diseased and control tissue. Infiltrating cells expressed very low levels of active TGF-beta. By ELISA, very low levels (0-69 pg/mg) of soluble total or active TGF-beta were detected in hypotonic tissue lysates. TGF-beta1 and TGF-beta3 are produced by SCID mouse colon and transcription is increased in the colitis caused by transplantation of CD4+ T-cells, but this does not result in high levels of soluble active protein. Low levels of active TGF-beta may be a factor contributing to unresolved inflammation.

Animals↗
PubMed2001

Challenges in incorporating a quality strategy into information systems development efforts.

Quality is an essential element of conducting successful information systems (IS) initiatives. While quality is a critical issue, statistics indicate that between one and two thirds of IS projects fail and of the most expensive software projects, about half eventually will be canceled for being out of control. This article examines the three phases of quality management and how these relate to IS development. This article illustrates the challenges faced in incorporating quality into an IS development effort and concludes with observations about the general states of IS development quality.

Information Systems↗
PubMed2000

Transfer and motor skill learning in association football.

Transfer of learning involves the influence of previous experiences on the performance or learning of new skills. It is defined as a gain (or loss) in the capability for performance on one task as a result of practice on another. The aim of the study was to examine the degree of transfer between various association football skills. Twenty intermediate male players participated in the study. During pre- and post-training tests, participants juggled a football as many times as possible within 30 s using feet or knees. Further tests required participants to control an approaching football inside a restricted area using the preferred and non-preferred kicking leg. Following performance on the pretest, two matched skill groups were obtained. One group participated in a 4-week training period in which feet-only ball juggling was practised for 10 min daily, while the remaining group acted as a control. Trained participants exhibited superior post-test performance on knee juggling and ball control with preferred and non-preferred leg tasks relative to the control group (p < 0.05). Findings indicate positive transfer of learning from juggling practice with the feet to juggling with the knees and a football control task. Implications for theory and practice are highlighted.

Adult↗
PubMed2000

Talent identification and development in soccer.

In this review, we attempt to integrate the main research findings concerned with talent identification and development in soccer. Research approaches in anthropometry, physiology, psychology and sociology are considered and, where possible, integrated. Although some progress has been made in identifying correlates of playing success, it appears that no unique characteristics can be isolated with confidence. Both biological and behavioural scientists have indicated a strong genetic component in performance of sports such as soccer; nevertheless, the influence of systematic training and development programmes should not be underestimated. We conclude that the sport and exercise sciences have an important support role in the processes of identifying, monitoring and nurturing talented soccer players towards realizing their potential.

Anthropometry↗
PubMed2000

A multidisciplinary approach to talent identification in soccer.

The requirements for soccer play are multifactorial and distinguishing characteristics of elite players can be investigated using multivariate analysis. The aim of the present study was to apply a comprehensive test battery to young players with a view to distinguishing between elite and sub-elite groups on the basis of performance on test items. Thirty-one (16 elite, 15 sub-elite) young players matched for chronological age (15-16 years) and body size were studied. Test items included anthropometric (n = 15), physiological (n = 8), psychological (n = 3) and soccer-specific skills (n = 2) tests. Variables were split into separate groups according to somatotype, body composition, body size, speed, endurance, performance measures, technical skill, anticipation, anxiety and task and ego orientation for purposes of univariate and multivariate analysis of variance and stepwise discriminant function analysis. The most discriminating of the measures were agility, sprint time, ego orientation and anticipation skill. The elite players were also significantly leaner, possessed more aerobic power (9.0 +/- 1.7 vs 55.5 +/- 3.8 ml x kg(-1) x min(-1)) and were more tolerant of fatigue (P < 0.05). They were also better at dribbling the ball, but not shooting. We conclude that the test battery used may be useful in establishing baseline reference data for young players being selected onto specialized development programmes.

Adolescent↗