Contact dermatitis and other skin conditions in instrumental musicians

BACKGROUND: The skin is important in the positioning and playing of a musical instrument. During practicing and performing there is a permanent more or less intense contact between the instrument and the musician's skin. Apart from aggravation of predisposed skin diseases (e.g., atopic eczema or psoriasis) due to music-making, specific dermatologic conditions may develop that are directly caused by playing a musical instrument. METHODS: To perform a systematic review on instrument-related skin diseases in musicians we searched the PubMed database without time limits. Furthermore we studied the online bibliography "Occupational diseases of performing artist. A performing arts medicine bibliography. October, 2003" and checked references of all selected articles for relevant papers. RESULTS: The most prevalent skin disorders of instrumental musicians, in particular string instrumentalists (e.g., violinists, cellists, guitarists), woodwind players (e.g., flautists, clarinetists), and brass instrumentalists (e.g., trumpeters), include a variety of allergic contact sensitizations (e.g., colophony, nickel, and exotic woods) and irritant (physical-chemical noxae) skin conditions whose clinical presentation and localization are usually specific for the instrument used (e.g., "fiddler's neck", "cellist's chest", "guitar nipple", "flautist's chin"). Apart from common callosities and "occupational marks" (e.g., "Garrod's pads") more or less severe skin injuries may occur in musical instrumentalists, in particular acute and chronic wounds including their complications. Skin infections such as herpes labialis seem to be a more common skin problem in woodwind and brass instrumentalists. CONCLUSIONS: Skin conditions may be a significant problem not only in professional instrumentalists, but also in musicians of all ages and ability. Although not life threatening they may lead to impaired performance and occupational hazard. Unfortunately, epidemiological investigations have exclusively been performed on orchestra musicians, though the prevalence of instrument-related skin conditions in other musician groups (e.g., jazz and rock musicians) is also of interest. The practicing clinician should be aware of the special dermatologic problems unique to the musical instrumentalist. Moreover awareness among musicians needs to be raised, as proper technique and conditioning may help to prevent affection of performance and occupational impairment

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Introducing the analysis of bifurcation in dynamical systems by symbolic computation

The aim of this paper is to introduce a few topics about nonlinear systems that are usual in electrical engineering but are frequently disregarded in undergraduate courses. More precisely, the main subject of this paper is to present the analysis of bifurcations in dynamical systems through the use of symbolic computation. The necessary conditions for the occurrence of Hopf, saddle-node, transcritical or pitchfork bifurcations in first order state space nonlinear equations depending upon a vector of parameters are expressed in terms of symbolic computation. With symbolic computation, the relationship between the state variables and the parameters that play a crucial role in the occurrence of such phenomena can be established. Firstly, the symbolic computation is applied to a third order dynamic Lorenz system in order to familiarise the students with the technique. Then, the symbolic routines are used in the analysis of the simplified model of a power system, bringing new insights and a deeper understanding about the occurrence of these phenomena in physical systems.44428930

Analysis of piecewise-linear oscillators with hysteresis

This brief proposed applying the point transformation method of Andronov to analyze the different kinds of oscillation that may occur in piecewise-linear systems, of the first, second, and third order, when a relay with hysteresis is used in the feedback loop.5081120112

Estudo eletromiográfico da deglutição na musculatura supra-hióidea em sujeitos Classe Ie III de Angle Electromyographic study of swallowing in suprahyoid musculature in Angle's Class I and III subjects

OBJETIVO: comparar a atividade elétrica do músculo supra-hióideo durante a deglutição em sujeitos com distintos padrões morfológicos e dentários. MÉTODOS: foram realizados registros eletromiográficos de superfície em 32 voluntários saudáveis e sem Disfunção Temporomandibular, subdivididos em dois grupos, 16 sujeitos Classes I e 16 Classe III de Angle, gênero masculino e feminino, com faixa etária entre 18 e 25 anos de idade. RESULTADOS: foram obtidos os valores do Root Mens Square (p< 0,05): original Classe I (15,238) e Classe III (32,550); normalizado pelo pico máximo Classe I (29,765) e Classe III (42,094); normalizado pela média Classe I (29,332) e Classe III (42,327). Período ativo do ciclo (p<0,05) Classe I (29,7648) e Classe III (42,0937); instante de máxima atividade (p>0,05) Classe I (47,6485) e Classe III (47,9437). CONCLUSÃO: os sujeitos Classe I demonstraram uma amplitude média menor, com aumento e diminuição da atividade elétrica sincrônica e equilibrada. Os sujeitos Classe III apresentaram uma amplitude média e um período ativo maior, assincrônico e desequilibrado durante a deglutição.<br>PURPOSE: to compare Suprahyoid musculature's electric activity during swallowing in subjects with dissimilar morphological and dental patterns. METHODS: surface Electromyography's records were taken from 32 healthy volunteers who do not have Temporomandibular Dysfunction, subdivided into two groups, Angle's 16 Class I subjects and 16 Class III subjects, males and females, aging from 18 to 25-year old. RESULTS: the values to Root Mens Square (p< 0.05): original Class I (15.238) e Class III (32.550); normalized by maximum peak Class I (29.765) e Class III (42.094); normalized by medium Class I (29.332) e Class III (42.327). Cycle's active period (p<0.05) Class I (29.7648) e Class III (42.0937); maximum activity instance (p>0.05) Class I (47.6485) e Class III (47.9437). CONCLUSION: class I subjects showed a smaller average amplitude, with increase and decrease of synchronized and balanced electric activity. Class III subjects showed a larger average amplitude and a larger desynchronized and unbalanced period during deglutition

CAR Modulates E-Cadherin Dynamics in the Presence of Adenovirus Type 5

Adenovirus (Ad) serotype 5 (Ad5) fiber competitively binds to the coxsackievirus and Ad receptor (CAR) to attach Ad5 to target cells and also disrupts cell junctions and facilitates virus escape at a late stage in Ad5 infection. Here we demonstrate that paracellular permeability in MCF7 and CAR overexpressing MCF7 (FLCARMCF7) cells is increased within minutes following the addition of Ad5 to cells. This is brought about, at least in part, by altering the molecular dynamics of E-cadherin, a key component of the cell-cell adhesion complex. We also demonstrate that the increase in E-cadherin mobility is constitutively altered by the presence of CAR at FLCARMCF7 cell junctions. As increased paracellular permeability was observed early after the addition of Ad5 to cells, we postulate that this may represent a mechanism by which Ad5 could disrupt cell junctions to facilitate further access to its cell receptors