A wearable multi-sensor system for real world gait analysis.

Gait analysis is commonly performed in standardized environments, but there is a growing interest in assessing gait also in ecological conditions. In this regard, an important limitation is the lack of an accurate mobile gold standard for validating any wearable system, such as continuous monitoring devices mounted on the trunk or wrist. This study therefore deals with the development and validation of a new wearable multi-sensor-based system for digital gait assessment in free-living conditions. In particular, results obtained from five healthy subjects during lab-based and real-world experiments were presented and discussed. The in-lab validation, which assessed the accuracy and reliability of the proposed system, shows median percentage errors smaller than 2% in the estimation of spatio-temporal parameters. The system also proved to be easy to use, comfortable to wear and robust during the out-of-lab acquisitions, showing its feasibility for free-living applications.

Inter-leg Distance Measurement as a Tool for Accurate Step Counting in Patients with Multiple Sclerosis.

Step detection is commonly performed using wearable inertial devices. However, methods based on the extraction of signals features may deteriorate their accuracy when applied to very slow walkers with abnormal gait patterns. The aim of this study is to test and validate an innovative step counter method (DiSC) based on the direct measurement of inter-leg distance. Data were recorded using an innovative wearable system which integrates a magneto-inertial unit and multiple distance sensors (DSs) attached to the shank. The method allowed for the detection of both left and right steps using a single device and was validated on thirteen people affected by multiple sclerosis (0 <; EDSS <; 6.5) while performing a six-minute walking test. Two different measurement ranges for the distance sensor were tested (DS200: 0-200 mm; DS400: 0-400 mm). Accuracy was evaluated by comparing the estimates of the DiSC method against video recordings used as gold standard. Preliminary results showed a good accuracy in detecting steps with half the errors in detecting the step of the instrumented side compared to the non-instrumented (mean absolute percentage error 2.4% vs 4.8% for DS200; mean absolute percentage error 2% vs 5.4% for DS400). When averaging errors across patients, over and under estimation errors were compensated, and very high accuracy was achieved (E%<; 1.2% for DS200; E%<; 0.7% for DS400). DS400 is the suggested configuration for patients walking with a large base of support.

Assessing impact of organised breast screening across small residential areas-development and internal validation of a prediction model.

Monitoring screening mammography effects in small areas is often limited by small numbers of deaths and delayed effects. We developed a risk score for breast cancer death to circumvent these limitations. Screening, if effective, would increase post-diagnostic survivals through lead-time and related effects, as well as mortality reductions. Linked cancer and BreastScreen data at four hospitals (n = 2,039) were used to investigate whether screened cases had higher recorded survivals in 13 small areas, using breast cancer deaths as the outcome (M1), and a risk of death score derived from TNM stage, grade, histology type, hormone receptor status, and related variables (M2). M1 indicated lower risk of death in screened cases in 12 of the 13 areas, achieving statistical significance (p < .05) in 5. M2 indicated lower risk scores in screened cases in all 13 areas, achieving statistical significance in 12. For cases recently screened at diagnosis (<6 months), statistically significant reductions applied in 8 areas (M1) and all 13 areas (M2). Screening effects are more detectable in small areas using these risk scores than death itself as the outcome variable. An added advantage is the application of risk scores for providing a marker of screening effect soon after diagnosis.

A systematic review of surgical biopsy for LCIS found at core needle biopsy - do we have the answer yet?

BACKGROUND: The natural history of lobular carcinoma in-situ (LCIS) suggests that women are at increased risk of subsequent invasive breast cancer. Questions of effective management for women with this lesion have led to the need for evidence-based guidance and, in particular, guidance regarding management after LCIS is found at core needle biopsy (CNB). METHODS: A systematic review was conducted to determine the most appropriate management for women with LCIS found at CNB. A comprehensive search of the scientific literature was conducted to identify the literature pertaining to this population. Critical appraisal of the literature, data extraction and a narrative synthesis of the results were conducted. The outcome of interest was upgrade of diagnosis to invasive breast cancer or ductal carcinoma in-situ (DCIS). RESULTS: Sparse data, with limited generalisability and considerable uncertainty, are available for women with LCIS at CNB. Nine studies were identified that met pre-specified inclusion criteria. The reported estimates of upgrade of diagnosis from LCIS to invasive breast cancer or DCIS ranged from 2% to 25%. The body of evidence was limited by its retrospective nature, risk of selection bias and poor generalisability to all women with LCIS at CNB. Further, higher quality research is required to determine the best approach for women with LCIS at CNB with any certainty.

Extracorporeal membrane oxygenation for cardiorespiratory failure in four patients with pandemic H1N1 2009 influenza virus and secondary bacterial infection.

We report four patients with pandemic H1N1 2009 influenza virus and secondary bacterial infection who were treated with extracorporeal membrane oxygenation (ECMO) for cardiorespiratory failure. Three of the four patients had profound shock, necessitating support with venoarterial ECMO. Two patients died during ECMO support. The two survivors had prolonged hospital stays, which were complicated by renal failure and limb ischaemia.

Syphilis outbreak in Walsall, UK: lessons for control and prevention.

An assessment of risk-taking behaviour among men who have sex with men (MSM) attending a sauna venue was undertaken, using a standardized questionnaire, after which outreach screening was introduced targeting MSM. The epidemiology of the continuing outbreak of syphilis was reviewed to determine the factors driving the outbreak and assess the benefit of continuing outreach screening. Findings among the 163 respondents at the sauna included a high rate of casual sex and a tendency not to disclose HIV status. Over 12 months, 51 cases of early syphilis were recorded. Our review showed a decline in incidence in MSM after outreach screening, but an increase in heterosexual spread. Given the frequent anonymous nature of syphilis transmission, traditional contact tracing is ineffective. Outreach screening is required at gay venues and other community settings to target at-risk populations.

An evaluation of digital, split-site and traditional formats in conference poster sessions.

The paper reports an evaluation of digital, split-site and traditional poster presentations at the Association for Medical Education in Europe (AMEE) conference in September 2004. The programme included 300 posters in 19 sessions, viewed, potentially, by 1265 conference participants, in parallel with other events. The instrument was a questionnaire of 16 open- and closed-format questions applied opportunistically and gaining 250 complete responses. Qualitative and quantitative analysis suggested that no one format was preferred. Each had different strengths and weaknesses relating to seeing and hearing the presenter and viewing the poster. Opportunities for discussion were highly valued.

Optotype acuity and re-operation rate after unilateral cataract surgery during the first 6 months of life with or without IOL implantation.

AIMS: To compare optotype acuities and re-operation rates in children corrected with a contact lens (CL) compared with an intraocular lens (IOL) following unilateral cataract extraction during infancy in a non-randomised, retrospective case series. METHODS: 25 infants with a unilateral congenital cataract underwent cataract surgery with (IOL group, n = 12) or without (CL group, n = 13) IOL implantation when <7 months of age. Optotype acuities were assessed in 19 of these children at a mean age of 4.3 years (range 3.3-5.5 years). The number of re-operations were assessed in 21 children. RESULTS: The visual acuity results were similar in the two treatment groups (p = 0.99); however, two of the four (50%) children in the IOL group compared with two of the seven (28%) children in the CL group undergoing surgery during the first 6 weeks of life had 20/40 or better visual acuity. The children in the IOL group had more re-operations than the children in the CL group (mean 1.1 v 0.36). Most of the re-operations in the IOL group were membranectomies performed during the first year of life (median 8.0 months) whereas all of the re-operations in the CL group were the implantation of a secondary IOL later in childhood (mean 2.2 years). CONCLUSION: Optotype acuities were similar for the children corrected with a CL compared with IOL, while the children in the IOL group underwent more re-operations .

Perioperative plasma concentrations of stable nitric oxide products are predictive of cognitive dysfunction after laparoscopic cholecystectomy.

In this study our objectives were to determine the incidence of postoperative cognitive dysfunction (POCD) after laparoscopic cholecystectomy under sevoflurane anesthesia in patients aged >40 and <85 yr and to examine the associations between plasma concentrations of i) S-100beta protein and ii) stable nitric oxide (NO) products and POCD in this clinical setting. Neuropsychological tests were performed on 42 ASA physical status I-II patients the day before, and 4 days and 6 wk after surgery. Patient spouses (n = 13) were studied as controls. Cognitive dysfunction was defined as deficit in one or more cognitive domain(s). Serial measurements of serum concentrations of S-100beta protein and plasma concentrations of stable NO products (nitrate/nitrite, NOx) were performed perioperatively. Four days after surgery, new cognitive deficit was present in 16 (40%) patients and in 1 (7%) control subject (P = 0.01). Six weeks postoperatively, new cognitive deficit was present in 21 (53%) patients and 3 (23%) control subjects (P = 0.03). Compared with the "no deficit" group, patients who demonstrated a new cognitive deficit 4 days postoperatively had larger plasma NOx at each perioperative time point (P < 0.05 for each time point). Serum S-100beta protein concentrations were similar in the 2 groups. In conclusion, preoperative (and postoperative) plasma concentrations of stable NO products (but not S-100beta) are associated with early POCD. The former represents a potential biochemical predictor of POCD.

Bragg gratings in air-silica structured fibers.

We report on grating writing in air-silica structured optical fibers with pure silica cores by use of two-photon absorption at 193 nm. A decrease in propagation loss with irradiation was observed. The characteristic growth curves were obtained.

Propagation in air by field superposition of scattered light within a Fresnel fiber.

Propagation of light at 1.5 microm with peak intensity in an air hole is achieved within an air-silica-structured Fresnel waveguide. Thus a simpler fiber design alternative to photonic crystal fibers is possible for high-peak-power propagation with reduced nonlinear interactions. Multiple foci are observed in the far field.

Multiple source generation using air-structured optical waveguides for optical field shaping and transformation within and beyond the waveguide.

In this paper we review recent results describing the generation of optical modes within waveguides based on coherent scattering from artificially structured interfaces. The generation of optical waveguide propagation similar to free space propagation enables possible solutions to controlling and shaping optical field generation in free space using coherent scattering of multiple sources. It is shown that the controlled fabrication of such sources can be done simply with air-material structured waveguides such as air-silica structured fibres. Further, the technique of coherent superposition is well known in Fresnel optics, exploiting zone plates to correct the necessary phase adjustments for a desired lens performance. Similarly, in waveguide form this allows fine control of the interference process resulting in the desired mode field and its properties within the waveguide, at the end of the waveguide in the near field regime and well beyond the waveguide into the far field. A factor that can contribute significantly to the coherent scattering within the Fresnel waveguide is resonant-like scattering inside the low index regions since the critical angle of propagation can be very small, increasing Fresnel reflections between interfaces. The results presented here open up a range of hitherto unexplored possibilities in controlling and shaping at first glance disparate phenomena, including free space diffraction.

All-fibre photonic crystal distributed Bragg reflector (PC-DBR) fibre laser.

We describe an Er3+-doped aluminosilicate core photonic crystal fibre laser incorporating distributed Bragg reflectors written by two-photon 193nm irradiation through an optical phase mask as the feedback elements. The laser is diode pumped at 980nm and evidence of dual linewidth laser operation close to threshold is observed. However, at higher pumping levels gain competition preferentially selects one laser line.

A framework for developing excellence as a clinical educator.

The current emphasis on providing quality undergraduate and postgraduate medical education has focused attention on the educational responsibilities of all doctors. There is a greater awareness of the need to train doctors as educators and courses have been set up to satisfy this need. Some courses, such as those on how to conduct appraisal, are specific to one task facing a medical educator. Other courses take a broader view and relate educational theory to practice. In this paper we describe an outcome-based approach in which competence in teaching is defined in terms of 12 learning outcomes. The framework provides a holistic approach to the roles of the teacher and supports the professionalism of teaching. Such a framework provides the basis for the development of a curriculum for teaching excellence. It helps to define important competences for different categories of teachers, communicate the areas to be addressed in a course, identify gaps in course provision, evaluate courses, assist in staff planning and allow individuals to assess their personal learning needs. The framework is presented to encourage wider debate.

A comparison of grating visual acuity, strabismus, and reoperation outcomes among children with aphakia and pseudophakia after unilateral cataract surgery during the first six months of life.

PURPOSE: The method of correcting aphakia after unilateral cataract extraction during infancy is controversial. Some authorities advocate correction with an intraocular lens (IOL) whereas others advocate correction with a contact lens (CL). We compared grating visual acuity, alignment, and reoperative outcomes in age-matched children treated with these 2 modalities at 5 clinical centers. METHODS: Twenty-five infants born in 1997 or 1998 with a dense unilateral congenital cataract who had cataract surgery coupled with (IOL group, n = 12) or without (CL group, n = 13) primary IOL implantation were enrolled in this study. All patients were prescribed half-time occlusion therapy. In July 1999, their grating visual acuities, ocular alignments, and reoperation rates were assessed. RESULTS: The mean grating visual acuity (LogMAR) for the affected eye was 0.70 +/- 0.32 for the IOL group and 0.87 +/- 0.31 for the CL group (P =.19). The mean interocular difference in grating visual acuity was 0.26 +/- 0.30 for the IOL group and 0.50 +/- 0.28 for the CL group (P =.048). The incidence of strabismus (>10 PD) was 75% in the IOL group compared with 92% in the CL group (P =.24). The incidence of reoperations was 83% in the IOL group compared with 23% in the CL group (P =.003). CONCLUSIONS: Our preliminary data suggest that correcting aphakia after unilateral congenital cataract surgery with primary IOL implantation results in an improved visual outcome but a higher rate of complications requiring reoperation. A randomized clinical trial, the Infant Aphakia Treatment Study, is planned to further study the optimal treatment for aphakia following unilateral cataract extraction during infancy.

Helicoverpa armigera granulovirus interference with progression of H. zea nucleopolyhedrovirus disease in H. zea larvae.

Capsular proteins from Helicoverpa armigera granulovirus (HaGV) have previously been shown to enhance H. armigera nucleopolyhedrovirus (HaSNPV) infection in H. armigera larvae. Yet, HaGV and HaS-NPV, as viable viruses, interfered with one another. In our study, we have examined the effects of co-infection of the slow-killing virus HaGV with the fast-killing virus Helicoverpa zea NPV (HzSNPV) on H. zea larvae. The mortality parameter measured was survival time. Virus stocks had 50% lethal concentrations of 3.2x10(-9) g HaGV-infected cadavers (GVC) (HaGV) and 32 occlusion bodies (HzSNPV) per cup. Average survival times were 16.8 and 5.5 days for larvae treated with HaGV and HzSNPV, respectively; death of HzSNPV-treated larvae was as early as 72 h posttreatment. In co-infection experiments in which larvae were treated concurrently with both viruses, the viruses competed in typical fashion for host resources. However, interference with disease progression in HzSNPV-fed larvae occurred even when HaGV was fed to larvae up to 36 h after the NPV, a time at which NPV infection should have been well established in host larvae. At death, co-infected larvae were observed microscopically to be filled with HaGV granules rather than HzSNPV polyhedra. The time study results imply that HaGV might be outcompeting HzSNPV by inhibiting its replication. We also observed that H. zea larvae treated with high dosages of HaGV (> or =3x10(-5) g GVC) were initially stunted but had survival times similar to those of larvae treated with lower dosages.

Combined superior oblique muscle recession and inferior oblique muscle advancement and transposition for cyclotorsion associated with macular translocation surgery.

PURPOSE: The purpose of this study was to evaluate the effects of oblique muscle surgery on the large-angle incyclotorsion resulting from macular translocation surgery for severe age-related macular degeneration. METHODS: Patients undergoing macular translocation (superiorly) at our institution from May 1996 until November 1998 were included. In the Staged Group, strabismus surgery for symptomatic incyclotorsion was performed after the macular translocation, and in the Combined Group, it was performed simultaneous with the macular translocation. Cyclotorsion was quantified using Maddox rod testing. Surgery for incyclotorsion included superior oblique muscle recession combined with inferior oblique muscle advancement and transposition in the affected eyes. The minimum follow-up time was 6 weeks. RESULTS: Fifteen patients (15 eyes) were included (ages 66-89 years). Nine eyes (Baseline Group) had macular translocation surgery before any strabismus surgery; the mean postoperative incylotorsional angle was 33.4 +/- 18.3 degrees (range, 20-80 degrees) after a mean follow-up of 6.6 months. Four of these eyes (Staged Group) underwent oblique muscle surgery for symptomatic incyclotorsion, which reduced the mean incyclotorsion from 26.9 +/- 6.9 degrees (range, 20-35 degrees) to 9. 9 +/- 7.9 degrees (range, 2.5-20 degrees)-a mean reduction of 16.9 +/- 1.3 degrees (P =.00012), after a mean follow-up of 4.6 months. Six additional eyes (Combined Group) had simultaneous macular translocation and oblique muscle surgery, with a mean postoperative cyclotorsional angle of 14.0 +/- 6.7 degrees (range, 4-22.5 degrees), after a mean follow-up of 3.75 months. CONCLUSION: Oblique muscle surgery is effective at reducing the large degree of incyclotorsion resulting from macular translocation surgery and may be used either following or simultaneous with retinal surgery.