A Robust Solution Procedure for Hyperelastic Solids with Large Boundary Deformation

Compressible Mooney-Rivlin theory has been used to model hyperelastic solids, such as rubber and porous polymers, and more recently for the modeling of soft tissues for biomedical tissues, undergoing large elastic deformations. We propose a solution procedure for Lagrangian finite element discretization of a static nonlinear compressible Mooney-Rivlin hyperelastic solid. We consider the case in which the boundary condition is a large prescribed deformation, so that mesh tangling becomes an obstacle for straightforward algorithms. Our solution procedure involves a largely geometric procedure to untangle the mesh: solution of a sequence of linear systems to obtain initial guesses for interior nodal positions for which no element is inverted. After the mesh is untangled, we take Newton iterations to converge to a mechanical equilibrium. The Newton iterations are safeguarded by a line search similar to one used in optimization. Our computational results indicate that the algorithm is up to 70 times faster than a straightforward Newton continuation procedure and is also more robust (i.e., able to tolerate much larger deformations). For a few extremely large deformations, the deformed mesh could only be computed through the use of an expensive Newton continuation method while using a tight convergence tolerance and taking very small steps.Comment: Revision of earlier version of paper. Submitted for publication in Engineering with Computers on 9 September 2010. Accepted for publication on 20 May 2011. Published online 11 June 2011. The final publication is available at http://www.springerlink.co

Remote control of a robotic hand using a leap sensor

This paper presents a low-cost gesture-based remote control of a ro-botic hand. The proposed control architecture is based on a commercial leap motion sensor and an Arduino board, which have been chosen due to their low-cost and user-friendly features. A specific Matlab code has been implemented to collect data from the leap motion sensor and to generate proper instructions to control a robotic hand, which has been 3D print at Sheffield Hallam Univer-sity. Experimental tests have been carried out validate the effectiveness of the proposed remote control for performing various grasping tasks

Expression pattern of class I histone deacetylases in vulvar intraepithelial neoplasia and vulvar cancer: a tissue microarray study

BACKGROUND: Epigenetic regulation is an important mechanism leading to cancer initiation and promotion. Histone acetylation by histone deacetylases (HDACs) represents an important part of it. The development of HDAC inhibitors has identified the utility of HDACs as a therapeutic target. Little is known about the epigenetic regulation of vulvar intraepithelial neoplasia (VIN) and vulvar squamous cell cancer (VSCC). In this study, the expression of class I HDACs (HDAC 1, 2 and 3) was compared in a series of VIN and VSCC tissues. METHODS: A tissue micro array (TMA) with specimens from 106 patients with high-grade VIN and 59 patients with vulvar cancer was constructed. The expression of HDACs 1, 2 and 3 were analyzed with immunohistochemistry (IHC). The nuclear expression pattern was evaluated in terms of intensity and percentage of stained nuclei and was compared between vulvar preinvasive lesions and vulvar cancer. RESULTS: HDAC 2 expression was significantly higher in VIN than in VSCC (p < 0.001, Fisher's test). Also, 88.7% (n=94/106) of VIN samples and only 54.5% (n=31/57) of VSCC samples were scored at the maximum level. Conversely, HDAC 3 expression was significantly higher in VSCC (93%, 53/57) compared to VIN (73.6%, 78/106, p=0.003), whereas only a small difference in the expression of HDAC 1 was found between these two entities of vulvar neoplasia. CONCLUSIONS: These results suggest that epigenetic regulation plays a considerable role in the transformation of VIN to invasive vulvar neoplasia

Assessment of Stormflow and Water Quality from Undisturbed and Site Prepared Forest Land in East Texas (Final Report)

In 1979, nine small forested watersheds were instrumented in East Texas to determine the effect of intensive forest management practices On water quantity and quality. Three replications of three treatments were used: 1) clearcutting - followed by shearing and windrowing, 2) clearcutting - followed by roller chopping and 3) undisturbed control. Following treatment, the sheared and windrowed sites exposed 57% of the surface soil compared to 16% for the chopped watersheds. During 1981, the first year after treatment, stormflow volumes increased with the intensity of the site disturbance. Sites sheared produced the greatest amount of stormflow (5.76 inches), followed by chopped (3.26 inches) and the undisturbed watersheds (1.03 inches). Stormflow volumes decreased 66% and 57% on the sheared and chopped watersheds the second year following treatment. Sediment losses were significantly higher on the sheared watersheds (2,620 lb/acre) than the chopped (22 lb/acre), during 1981. By the fall of 1982, the exposure of mineral soil on the sheared sites dropped to 20% and to 4% on the chopped sites. For this reason and the lower volume of runoff, sediment loss for 1982 dropped to 71.3, 4.9 and 4.5 lb/acre for the sheared, chopped and undisturbed watersheds, respectively. Nitrate concentrations were significantly different between treatments during 1981: Sheared - 205 ppb, chopped - 96 ppb and control 10 ppb. During 1982, although nitrate concentrations were lower, the sheared watershed still had a significantly higher concentration. Total nitrogen concentration on the sheared sites was 2,155 ppb, which was significantly higher than the chopped (999 ppb) or the control sites (996 ppb) for 1981. The first year total nitrogen export from the sheared sites (2.79 lb/acre) was 3.5 times greater than the chopped loss (0.76 lb/acre) and 12 times greater than the loss on the control sites (0.24 lb/acre). The second year following treatment, total nitrogen concentrations were not significantly different and total nitrogen loss on the sheared areas was less than half of the loss recorded from the control sites during 1981. Total phosphorus concentrations for 1981 were 221, 85 and 54 ppb for the sheared, chopped and control watersheds, respectively. Total phosphorus loss for this period was only 0.297 lb/acre from the sheared treatments, but was significantly higher than the chopped or undisturbed treatments. A drop in sediment concentrations and runoff in 1982 reduced phosphorus losses on the sheared watersheds by over 90%. Calcium, potassium and sodium concentrations during 1981, were highest for the chopped treatments, while magnesium concentrations were highest on the sheared treatments. Export of these elements was greatest from the sheared sites, except for calcium, which was lost in greater quantities on the chopped sites. During 1982 there was no significant difference between treatments for Ca, Mg, K and Na concentrations. The rapid revegetation and reduction in exposed mineral soil that occurred on both sheared and chopped treatments during 1982, resulted in a decrease in runoff and sediment and nutrient losses. As the stabilization of sites continues, treatment differences should diminish. Limiting shearing and windrowing activities to the more gentle slopes will reduce first year erosion and prevent increases in sediment and nutrient losses. Roller chopping on the other hand, appears to cause only minor changes to water yield and quality on slopes of up to 25%

Anticholinergic medications in patients admitted with cognitive impairment or falls (AMiCI). The impact of hospital admission on anticholinergic cognitive medication burden. Results of a multicentre observational study

What is known and objectiveDrugs with anticholinergic properties increase the risk of falls, delirium, chronic cognitive impairment, and mortality and counteract procholinergic medications used in the treatment of dementia. Medication review and optimisation to reduce anticholinergic burden in patients at risk is recommended by specialist bodies. Little is known how effective this review is in patients who present acutely and how often drugs with anticholinergic properties are used temporarily during an admission. The aim of the study was to describe the changes in the anticholinergic cognitive burden (ACB) in patients admitted to hospital with a diagnosis of delirium, chronic cognitive impairment or falls and to look at the temporary use of anticholinergic medications during hospital stay. MethodsThis is a multi-centre observational study that was conducted in seven different hospitals in the UK, Finland, The Netherlands and Italy. Results and discussion21.1% of patients had their ACB score reduced by a mean of 1.7%, 19.7% had their ACB increased by a mean of 1.6%, 22.8% of DAP naive patients were discharged on anticholinergic medications. There was no change in the ACB scores in 59.2% of patients. 54.1% of patients on procholinergics were taking anticholinergics. Out of the 98 medications on the ACB scale, only 56 were seen. Medications with a low individual burden were accounting for 64.9% of the total burden. Anticholinergic drugs were used temporarily during the admission in 21.9% of all patients. A higher number of DAPs used temporarily during admission was associated with a higher risk of ACB score increase on discharge (OR=1.82, 95% CI for OR: 1.36-2.45, P What is new and conclusionThere was no reduction in anticholinergic cognitive burden during the acute admissions. This was the same for all diagnostic subgroups. The anticholinergic load was predominantly caused by medications with a low individual burden. More than 1 in 5 patients not taking anticholinergics on admission were discharged on them and similar numbers saw temporary use of these medications during their admission. More than half of patients on cholinesterase-inhibitors were taking anticholinergics at the same time on admission, potentially directly counteracting their effects.Peer reviewe

The FLASHForward Facility at DESY

The FLASHForward project at DESY is a pioneering plasma-wakefield acceleration experiment that aims to produce, in a few centimetres of ionised hydrogen, beams with energy of order GeV that are of quality sufficient to be used in a free-electron laser. The plasma wave will be driven by high-current density electron beams from the FLASH linear accelerator and will explore both external and internal witness-beam injection techniques. The plasma is created by ionising a gas in a gas cell with a multi-TW laser system, which can also be used to provide optical diagnostics of the plasma and electron beams due to the <30 fs synchronisation between the laser and the driving electron beam. The operation parameters of the experiment are discussed, as well as the scientific program.Comment: 19 pages, 9 figure

Clinical efficacy and satisfaction of a digital wheeze detector in a multicentre randomised controlled trial: the WheezeScan study.

INTRODUCTION: Wheezing is common in preschool children and its clinical assessment often challenging for caretakers. This study aims to evaluate the impact of a novel digital wheeze detector (WheezeScan™) on disease control in a home care setting. METHODS: A multicentre randomised open-label controlled trial was conducted in Berlin, Istanbul and London. Participants aged 4-84 months with a doctor's diagnosis of recurrent wheezing in the past 12 months were included. While the control group followed usual care, the intervention group received the WheezeScan™ for at-home use for 120 days. Parents completed questionnaires regarding their child's respiratory symptoms, disease-related and parental quality of life, and caretaker self-efficacy at baseline (T0), 90 days (T1) and 4 months (T2). RESULTS: A total of 167 children, with a mean±sd age of 3.2±1.6 years, were enrolled in the study (intervention group n=87; control group n=80). There was no statistically significant difference in wheeze control assessed by TRACK (mean difference 3.8, 95% CI -2.3-9.9; p=0.2) at T1 between treatment groups (primary outcome). Children's and parental quality of life and parental self-efficacy were comparable between both groups at T1. The evaluation of device usability and perception showed that parents found it useful. CONCLUSION: In the current study population, the wheeze detector did not show significant impact on the home management of preschool wheezing. Hence, further research is needed to better understand how the perception and usage behaviour may influence the clinical impact of a digital support

Prognostic value of histopathological regression in 850 neoadjuvantly treated oesophagogastric adenocarcinomas.

BACKGROUND Recently, histopathological tumour regression, prevalence of signet ring cells, and localisation were reported as prognostic factors in neoadjuvantly treated oesophagogastric (junctional and gastric) cancer. This exploratory retrospective study analyses independent prognostic factors within a large patient cohort after preoperative chemotherapy including clinical and histopathological factors. METHODS In all, 850 patients presenting with oesophagogastric cancer staged cT3/4 Nany cM0/x were treated with neoadjuvant chemotherapy followed by resection in two academic centres. Patient data were documented in a prospective database and retrospectively analysed. RESULTS Of all factors prognostic on univariate analysis, only clinical response, complications, ypTNM stage, and R category were independently prognostic (P<0.01) on multivariate analysis. Tumour localisation and signet ring cells were independently prognostic only when investigator-dependent clinical response evaluation was excluded from the multivariate model. Histopathological tumour regression correlates with tumour grading, Laurén classification, clinical response, ypT, ypN, and R categories but was not identified as an independent prognostic factor. Within R0-resected patients only surgical complications and ypTNM stage were independent prognostic factors. CONCLUSIONS Only established prognostic factors like ypTNM stage, R category, and complications were identified as independent prognostic factors in resected patients after neoadjuvant chemotherapy. In contrast, histopathological tumour regression was not found as an independent prognostic marker