Appendicular mass – a rare form of tuberculosis

Tuberculosis is in the top 10 causes of death worldwide, being one of the most deadly infectious diseases. It is estimated that one of three people from the entire earth population has a latent infection with M tuberculosis. This aerobic bacterium possesses the ability to persist in host tissues for years and to begin replication once immunity declines. The lungs are most frequent site of infection as the Mycobacterium tuberculosis is carried by aerosol droplets and is commonly transmitted by respiratory route. The second way of transmission is by contaminated food. Intestinal contamination coexists with pulmonary tuberculosis and only 10% represent primitive enteric diseases. The ileocecal region is involved most frequently. Even in this context isolated appendicular involvement remains rare. We report the case of appendicular tuberculosis in a 17-year-old woman with no evidence of other location of disease elsewhere in the body

Transient effects in lubricated textured bearings

The aim of this paper is to study the transient phenomena in hydrodynamic textured bearings. Both convergent and convergent–divergent reciprocating textured bearings are considered. A mass-conserving formulation of the Reynolds equation recently proposed by some of the authors and used to capture cavitation in steady-state lubricated contacts has been implemented to study transient effects in lubricated textured bearings. It is shown that the proposed solver is capable of capturing the frictional response of bearings characterised by various geometries and loading conditions in both steady-state and transient configurations. Depending on the boundary conditions governing the problems under investigation, changes in load support or film thickness variations are correctly predicted, demonstrating that the methodology developed in this paper is suitable to provide an efficient tool for the design and optimisation of textured bearings. A qualitative comparison with preliminary experimental data obtained using an apparatus developed to study reciprocating textured surfaces is performed, showing that the characteristic transient behaviour of such surfaces in different loading regimes can be correctly captured using the proposed numerical implementation. </jats:p

Transient experimental and modelling studies of laser-textured micro-grooved surfaces with a focus on piston-ring cylinder liner contacts

This paper presents a comparison between the results from numerical modelling and experiments to shed light on the mechanisms by which surface texture can reduce friction when applied to an automotive cylinder liner. In this configuration, textured features move relative to th e piston-liner conjunction and to account for this our approach is to focus on the transient friction response to individual pockets as they pass through, and then leave, the sliding contact. The numerical approach is based on the averaged Reynolds’ equat ion with the Patir & Cheng’s flow factors and the p- θ Elrod- Adams mass-conserving cavitation model. The contact pressures that arises from the asperity interactions are solved simultaneously to the fluid flow solution using the Greenwood and Tripp method. The experimental data is produced using a pin-on -disc set up, in which laser textured pockets have been applied to the disc specimen. Under certain conditions in the mixed and boundary lubrication regime s, both model and experimental results show i ) an increase in friction as the pocket enters the contact, followed by ii ) a sharp decrease as the pocket leaves the contact, and then iii ) a gradual decay back to the pre-entrainment value. From the evidence obtained for the first time from the proposed combined modelling and experimental investigation conducted under carefully controlled conditions, w e suggest that these three stages occur due to the following mechanisms: i ) a reduction in fluid pressure due to the increased inlet gap, ii ) inlet suction as the cavitated fluid within the pocket draws lubricant into the contact, and iii ) film thickness decay as oil is squeezed out of the contact. The interplay of these three mechanisms is shown to control the response of micro-textured surfaces under all lubrication regimes

Experimental validation of a mixed-lubrication regime model for textured piston-ring-liner contacts

Recent experiments have shown that automotive piston-liner friction may be reduced by up to 50 % if the surface of the liner is laser textured with certain configurations of micro-pockets. It is important to model this behavior to understand and optimize the friction reduction mechanisms that are occurring. However, until now, very few models that predict the lubrication performance of textured surfaces have been successfully validated against experimental data. This is because of the requirement for them to: (1) reproduce experimental configurations with a certain degree of fidelity, (2) conserve mass properly, and (3) account for transient, boundary lubrication conditions. To address this, the current paper presents a comparison between the results from a numerical model, which fulfils these criteria, and an experimental test rig operating under the same conditions. The mathematical modeling is based on the averaged Reynolds’ equation with Patir and Cheng’s flow factors and the p − θ Elrod–Adams mass-conserving cavitation model. Simultaneously to the fluid flow solution, the contact pressures that arise from the asperity interactions are also included into the calculations through the well-known stochastic Greenwood and Tripp model for rough contacts. The experimental data is produced using a reciprocating tribometer, whose contact conditions are closely controlled and accurately mimic those found in an automotive piston–liner conjunction. Data is presented in terms of friction force versus stroke angle, and the similarities and differences between the model and experiment are discussed

What’s the Big IDEA? A Preliminary Analysis of Behavior Analysts’ Self-Reported Training in and Knowledge of Federal Special Education Law

Many behavior analysts currently work in school settings or with individuals who may qualify for educational services through federal special education law. However, it remains unclear what training, if any, behavior analysts receive in this law. Behavior analysts have an ethical responsibility to practice within their scope of competency and in compliance with legal regulations. Thus, it is important to determine whether behavior analysts practicing in the United States are adequately prepared and familiar with federal special education law. The current study consisted of a survey wherein respondents answered questions pertaining to the relevance of federal special education law, their familiarity with core terminology, and the alignment between the law and the Professional and Ethical Compliance Code for Behavior Analysts (Behavior Analyst Certification Board, 2016). Respondents' self-report indicates that behavior analysts hold conflicting views on how federal special education law aligns with and influences their role as service providers. As such, practitioners and agencies alike may benefit from explicit clarification of the responsibility Board Certified Behavior Analysts have to seek training in and adhere to federal special education law.VoRSUNY DownstateApplied Behavior AnalysisN/

Liquid repellency enhancement through flexible microstructures

Artificial liquid-repellent surfaces have attracted substantial scientific and industrial attention with a focus on creating functional topological features; however, the role of the underlying structures has been overlooked. Recent developments in micro-nanofabrication allow us now to construct a skin-muscle type system combining interfacial liquid repellence atop a mechanically functional structure. Specifically, we design surfaces comprising bioinspired, mushroom-like repelling heads and spring-like flexible supports, which are realized by three-dimensional direct laser lithography. The flexible supports elevate liquid repellency by resisting droplet impalement and reducing contact time. This, previously unknown, use of spring-like flexible supports to enhance liquid repellency provides an excellent level of control over droplet manipulation. Moreover, this extends repellent microstructure research from statics to dynamics and is envisioned to yield functionalities and possibilities by linking functional surfaces and mechanical metamaterials

Filling an Emulsion Drop with Motile Bacteria

We have measured the spatial distribution of motile Escherichia coli inside spherical water droplets emulsified in oil. At low cell concentrations, the cell density peaks at the water-oil interface; at increasing concentration, the bulk of each droplet fills up uniformly while the surface peak remains. Simulations and theory show that the bulk density results from a `traffic' of cells leaving the surface layer, increasingly due to cell-cell scattering as the surface coverage rises above $\sim 10\%$. Our findings show similarities with the physics of a rarefied gas in a spherical cavity with attractive walls.Comment: 5 pages, 4 figures, Supporting Information (5 pages, 5 figures

Swimming in a crystal

We study catalytic Janus swimmers and Escherichia coli bacteria swimming in a two-dimensional colloidal crystal. The Janus swimmers orbit individual colloids and hop between colloids stochastically, with a hopping rate that varies inversely with fuel (hydrogen peroxide) concentration. At high fuel concentration, these orbits are stable for 100s of revolutions, and the orbital speed oscillates periodically as a result of hydrodynamic, and possibly also phoretic, interactions between the swimmer and the six neighbouring colloids. Motile E.~coli bacteria behave very differently in the same colloidal crystal: their circular orbits on plain glass are rectified into long, straight runs, because the bacteria are unable to turn corners inside the crystal

IDENTIFICATION OF OCCULT CEREBRAL MICROBLEEDS IN ADULTS WITH IMMUNE THROMBOCYTOPENIA

Management of symptoms and prevention of life-threatening hemorrhage in immune thrombocytopenia (ITP) must be balanced against adverse effects of therapies. Because current treatment guidelines based on platelet count are confounded by variable bleeding phenotypes, there is a need to identify new objective markers of disease severity for treatment stratification. In this cross-sectional prospective study of 49 patients with ITP and nadir platelet counts <30 × 109/L and 18 aged-matched healthy controls, we used susceptibility-weighted magnetic resonance imaging to detect cerebral microbleeds (CMBs) as a marker of occult hemorrhage. CMBs were detected using a semiautomated method and correlated with clinical metadata using multivariate regression analysis. No CMBs were detected in health controls. In contrast, lobar CMBs were identified in 43% (21 of 49) of patients with ITP; prevalence increased with decreasing nadir platelet count (0/4, ≥15 × 109/L; 2/9, 10-14 × 109/L; 4/11, 5-9 × 109/L; 15/25 <5 × 109/L) and was associated with longer disease duration (P = 7 × 10−6), lower nadir platelet count (P = .005), lower platelet count at time of neuroimaging (P = .029), and higher organ bleeding scores (P = .028). Mucosal and skin bleeding scores, number of previous treatments, age, and sex were not associated with CMBs. Occult cerebral microhemorrhage is common in patients with moderate to severe ITP. Strong associations with ITP duration may reflect CMB accrual over time or more refractory disease. Further longitudinal studies in children and adults will allow greater understanding of the natural history and clinical and prognostic significance of CMBs