Commentaries

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67348/2/10.1177_00030651970450031204.pd

How ions distribute in a drying porous medium: A simple model

Salt crystallization at surfaces is an important problem for buildings and monuments. We do not consider the formation of salt crystals as such, but focus on transport properties of ions in a drying porous medium. We deal with the first phase of the drying process, where the water is still uniformly distributed throughout the medium. An approximate model is presented, which accounts for both convection and diffusion. It is shown that the key parameter is the Peclet number at the evaporating surface, PehL/D, where h, L, , and D are the drying rate, sample size, porosity, and diffusion constant, respectively. When Pe1 (diffusion dominates over convection) the ions remain uniformly distributed throughout the system. Strong accumulation at the evaporating surface occurs for Pe1 (convection dominates over diffusion). Crossover behavior is found for Pe1. Therefore, it is likely that the first crystals will be formed both in the bulk and at the interfaces of the material when Pe1. For high values of Pe the density peak at the evaporating surface will reach the saturation concentration long before it is reached in the bulk of the material. As a consequence, the salt starts to crystallize at the interfaces

Comparing the Clinical and Histological Diagnosis of Leprosy and Leprosy Reactions in the INFIR Cohort of Indian Patients with Multibacillary Leprosy

Leprosy affects skin and peripheral nerves. Although we have antibiotics to treat the mycobacterial infection, the accompanying inflammation is a major part of the disease process. This can worsen after starting antibacterial treatment with episodes of immune mediated inflammation, so called reactions. These are associated with worsening of nerve damage. However, diagnosing these reactions is not straightforward. They can be diagnosed clinically by examination or by microscopic examination of the skin biopsies. We studied a cohort of 303 newly diagnosed leprosy patients in India and compared the diagnosis rates by clinical examination and microscopy and found that the microscopic diagnosis has higher rates of diagnosis for both types of reaction. This suggests that clinicians and pathologists have different thresholds for diagnosing reactions. More work is needed to optimise both clinical and pathological diagnosis. In this cohort 43% of patients had Borderline Tuberculoid leprosy, an immunologically active type, and 20% of the biopsies showed only minimal inflammation, perhaps these patients had very early disease or self-healing. The public health implication of this work is that leprosy centres need to be supported by pathologists to help with the clinical management of difficult cases

Effects of Impurity Content on the Sintering Characteristics of Plasma-Sprayed Zirconia

Yttria-stabilized zirconia powders, containing different levels of SiO2 and Al2O3, have been plasma sprayed onto metallic substrates. The coatings were detached from their substrates and a dilatometer was used to monitor the dimensional changes they exhibited during prolonged heat treatments. It was found that specimens containing higher levels of silica and alumina exhibited higher rates of linear contraction, in both in-plane and through-thickness directions. The in-plane stiffness and the through-thickness thermal conductivity were also measured after different heat treatments and these were found to increase at a greater rate for specimens with higher impurity (silica and alumina) levels. Changes in the pore architecture during heat treatments were studied using Mercury Intrusion Porosimetry (MIP). Fine scale porosity (<_50 nm) was found to be sharply reduced even by relatively short heat treatments. This is correlated with improvements in inter-splat bonding and partial healing of intra-splat microcracks, which are responsible for the observed changes in stiffness and conductivity, as well as the dimensional changes

Living with joint hypermobility syndrome: patient experiences of diagnosis, referral and self-care.

BACKGROUND: Musculoskeletal problems are common reasons for seeking primary health care. It has been suggested that many people with 'everyday' non-inflammatory musculoskeletal problems may have undiagnosed joint hypermobility syndrome (JHS), a complex multi-systemic condition. JHS is characterized by joint laxity, pain, fatigue and a wide range of other symptoms. Physiotherapy is usually the preferred treatment option for JHS, although diagnosis can be difficult. The lived experience of those with JHS requires investigation. OBJECTIVE: The aim of the study was to examine patients' lived experience of JHS, their views and experiences of JHS diagnosis and management. METHODS: Focus groups in four locations in the UK were convened, involving 25 participants with a prior diagnosis of JHS. The focus groups were audio recorded, fully transcribed and analysed using the constant comparative method to inductively derive a thematic account of the data. RESULTS: Pain, fatigue, proprioception difficulties and repeated cycles of injury were among the most challenging features of living with JHS. Participants perceived a lack of awareness of JHS from health professionals and more widely in society and described how diagnosis and access to appropriate health-care services was often slow and convoluted. Education for patients and health professionals was considered to be essential. CONCLUSIONS: Timely diagnosis, raising awareness and access to health professionals who understand JHS may be particularly instrumental in helping to ameliorate symptoms and help patients to self-manage their condition. Physiotherapists and other health professionals should receive training to provide biopsychosocial support for people with this condition

Cytokine and Protein Markers of Leprosy Reactions in Skin and Nerves: Baseline Results for the North Indian INFIR Cohort

Leprosy affects skin and peripheral nerves. Although we have effective antibiotics to treat the mycobacterial infection, a key part of the disease process is the accompanying inflammation. This can worsen after starting antibacterial treatment with episodes of immune mediated inflammation, so called ‘reactions’. These reactions are associated with worsening of the nerve damage. We recruited a cohort of 303 newly diagnosed leprosy patients in North India with the aim of understanding and defining the pathological processes better. We took skin and nerve biopsies from patients and examined them to define which molecules and mediators of inflammation were present. We found high levels of the cytokines Tumour Necrosis Factor alpha, Transforming Growth Factor beta and inducible Nitric Oxide Synthase in biopsies from patients with reactions. We also found high levels of bacteria and inflammation in the nerves. These experiments tell us that we need to determine which other molecules are present and to explore ways of switching off the production of these pro-inflammatory molecules