New insights into the biomechanics of Legg-Calvé-Perthes’ disease: The role of epiphyseal skeletal immaturity in vascular obstruction

ObjectivesLegg–Calvé–Perthes’ disease (LCP) is an idiopathic osteonecrosis of the femoral head that is most common in children between four and eight years old. The factors that lead to the onset of LCP are still unclear; however, it is believed that interruption of the blood supply to the developing epiphysis is an important factor in the development of the condition.MethodsFinite element analysis modelling of the blood supply to the juvenile epiphysis was investigated to understand under which circumstances the blood vessels supplying the femoral epiphysis could become obstructed. The identification of these conditions is likely to be important in understanding the biomechanics of LCP.ResultsThe results support the hypothesis that vascular obstruction to the epiphysis may arise when there is delayed ossification and when articular cartilage has reduced stiffness under compression.ConclusionThe findings support the theory of vascular occlusion as being important in the pathophysiology of Perthes disease

A General Formulation for Least-Squares Problems

Abstract — We show in this paper that many different least-squares problems which have applications in signal processing may be seen as special cases of a more general vector space minimization problem called the Minimum Norm problem. We show that special cases of the Minimum Norm problem include: least squares fitting of a finite set of points to a linear equation and to a quadratic equation; the infinite length MMSE-optimum linear equalizer; the finite length MMSE-optimum linear equalizer; the steepest descent algorithm and the more practical LMS algorithm for iterative estimation of the finite-length MMSE-optimum linear equalizer for an unknown channel; and the finite-length least-squares-optimum linear equalizer with a forgetting factor. These examples are not exhaustive but are chosen to illustrate the scope of this framework

Silicon and III-V compound nanotubes: structural and electronic properties

Unusual physical properties of single-wall carbon nanotubes have started a search for similar tubular structures of other elements. In this paper, we present a theoretical analysis of single-wall nanotubes of silicon and group III-V compounds. Starting from precursor graphene-like structures we investigated the stability, energetics and electronic structure of zigzag and armchair tubes using first-principles pseudopotential plane wave method and finite temperature ab-initio molecular dynamics calculations. We showed that (n,0) zigzag and (n,n) armchair nanotubes of silicon having n > 6 are stable but those with n < 6 can be stabilized by internal or external adsorption of transition metal elements. Some of these tubes have magnetic ground state leading to spintronic properties. We also examined the stability of nanotubes under radial and axial deformation. Owing to the weakness of radial restoring force, stable Si nanotubes are radially soft. Undeformed zigzag nanotubes are found to be metallic for 6 < n < 11 due to curvature effect; but a gap starts to open for n > 12. Furthermore, we identified stable tubular structures formed by stacking of Si polygons. We found AlP, GaAs, and GaN (8,0) single-wall nanotubes stable and semiconducting. Our results are compared with those of single-wall carbon nanotubes.Comment: 11 pages, 10 figure

Integrating user-centred design in the development of a silent speech interface based on permanent magnetic articulography

Abstract: A new wearable silent speech interface (SSI) based on Permanent Magnetic Articulography (PMA) was developed with the involvement of end users in the design process. Hence, desirable features such as appearance, port-ability, ease of use and light weight were integrated into the prototype. The aim of this paper is to address the challenges faced and the design considerations addressed during the development. Evaluation on both hardware and speech recognition performances are presented here. The new prototype shows a com-parable performance with its predecessor in terms of speech recognition accuracy (i.e. ~95% of word accuracy and ~75% of sequence accuracy), but significantly improved appearance, portability and hardware features in terms of min-iaturization and cost

Do preparticipation clinical exams reduce morbidity and mortality for athletes?

Though clinical preparticipation exams (PPE) are recommended by experts and required in most states, we found no medium- or better-quality evidence that demonstrates they reduce mortality or morbidity. PPEs detect only a very small percentage of cardiac abnormalities among athletes who subsequently die suddenly (strength of recommendation [SOR]: C, case series study). PPEs are also unable to accurately identify athletes with exercise-induced bronchospasm (SOR: C, small cross-sectional study) and are poorly predictive of which athletes are at increased risk of orthopedic injuries (SOR: C, cross-sectional study)

Electrochemical fecal pellet sensor for simultaneous real-time ex vivo detection of colonic serotonin signalling and motility

Various investigations have focused on understanding the relationship between mucosal serotonin (5-HT) and colonic motility, however contradictory studies have questioned the importance of this intestinal transmitter. Here we described the fabrication and use of a fecal pellet electrochemical sensor that can be used to simultaneously detect the release of luminal 5-HT and colonic motility. Fecal pellet sensor devices were fabricated using carbon nanotube composite electrodes that were housed in 3D printed components in order to generate a device that had shape and size that mimicked a natural fecal pellet. Devices were fabricated where varying regions of the pellet contained the electrode. Devices showed that they were stable and sensitive for ex vivo detection of 5-HT, and no differences in the fecal pellet velocity was observed when compared to natural fecal pellets. The onset of mucosal 5-HT was observed prior to the movement of the fecal pellet. The release of mucosal 5-HT occurred oral to the fecal pellet and was linked to the contraction of the bowel wall that drove pellet propulsion. Taken, together these findings provide new insights into the role of mucosal 5-HT and suggest that the transmitter acts as a key initiator of fecal pellet propulsion

A review of solar and visible light active TiO2 photocatalysis for treating bacteria, cyanotoxins and contaminants of emerging concern

Researchintothedevelopmentofsolarandvisiblelightactivephotocatalystshasbeensignificantlyincreased\ud inrecentyearsduetoitswiderangeofapplicationsintreatingcontaminantsofemergingconcern(CECs),\ud endocrine disruptingcompounds(EDCs), bacteriaandcyanotoxins.Solarphotocatalysisisfoundtobehighly\ud effectiveintreatingawiderangeofCECsfromsourcessuchaspharmaceuticals,steroids,antibiotics,phthalates,\ud disinfectants,pesticides,fragrances(musk),preservativesandadditives.Similarly,anumberofEDCsincluding\ud polycyclicaromatichydrocarbons(PAHs),alkylphenols(APs),bisphenolA(BPA),organotins(OTs),volatileor-\ud ganic compounds(VOCs),naturalandsyntheticestrogenicandandrogenicchemicals,pesticides,andheavy\ud metalscanberemovedfromcontaminatedwaterbyusingsolarphotocatalysis.Photocatalysiswasalsofound\ud effectiveintreatingawiderangeofbacteriasuchas Staphylococcusaureus,Bacillussubtilis,Escherichiacoli,\ud Salmonellatyphi and Micrococcuslylae. Thecurrentreviewalsocomparestheeffectivenessofvariousvisible\ud lightactivatedTiO2 photocatalystsfortreatingthesepollutants. Dopingorco-dopingofTiO2 usingnitrogen,\ud nitrogen–silver,sulphur,carbon,copperandalsoincorporation ofgraphenenano-sheetsarediscussed.Theuse\ud of immobilisedTiO2 for improvingthephotocatalyticactivityisalso presented.Decoratingtitaniaphotocatalyst\ud withgrapheneoxide(GO)isofparticularinterestduetoGO'sabilitytoincreasethephotocatalyticactivityof\ud TiO2. TheuseGOtoincreasethephotocatalyticactivityofTiO2 againstmicrocystin-LR(MC-LR)underUV-Aand\ud solarirciationisdiscussed.TheenhancedphotocatalyticactivityofGO–TiO2 comparedtothecontrolmaterialis\ud attributedtotheeffectiveinhibitionoftheelectron–holerecombinationbycontrollingtheinterfacialcharge\ud transferprocess.Itisconcludedthatthereisacriticalneedforfurtherimprovementoftheefficiencyofthese\ud materialsiftheyaretobeconsideredforbulkindustrialuse

What's the best treatment for sebaceous cysts?

Punch biopsy excision appears to be superior to traditional wide elliptical excision for the treatment of sebaceous cysts when intervention is necessary (strength of recommendation [SOR]: B, based on 1 small randomized study). No rigorous metho- dological studies have compared punch biopsy excision of sebaceous cysts with the minimal excision technique