Nail surface topography and onychochronobiology.

Peer reviewe

A unified dynamic similitude model for solid continuum

Copyright © 2022 The Authors. Dynamic similitude has proven to be a valuable tool, which is widely adopted in fluid mechanics. However, even with the ever-growing interest in dynamic similitude in solid mechanics, there is still no unified scaling law applicable to any given solid structure or system, and this has prevented the broad adoption of similitude in the field. Here we develop a unified similitude model for solid mechanics using the momentum and the energy conservation. The model allows for the use of different materials in both elastic and plastic regimes. Never reported dimensionless numbers are derived for the first time in this article, and this set of numbers is sufficient for strictly accurate dynamic similitude of any solid structure. Very different case studies are considered, and the perfect agreement seen in compared results confirms the accuracy of the developed scaling model. The exactness of the dimensionless numbers is also confirmed through analytical solutions. The model allows for the scaling of strain rate and, for the first time, the scaling of the strain state between the full-scale structure and its scaled replica

Numerical Investigation into the Effects of Turbulence Modelling on the Aeroelastic Analysis of Flexible Wings

Copyright © 2022 The Authors. As wings are becoming more flexible, existing aeroelastic analysis methods may struggle to accurately resolve the complex flow around oscillating wings. A numerical case study is performed to compare the aeroelastic predictions obtained for a wing with two degrees of freedom when turbulence models of varying fidelity are used. Results are presented and compared in the time and frequency domain for simulations using Reynolds Averaged Navier Stokes and Detached Eddy turbulence models. These results show significant differences be- tween the results obtained, particularly in the time domain. The numerical methodology, setup and results for this case study are presented in this paper

A Unified Dynamic Similitude of Solid Continuum and its Application in Aeroelastic Structures

Copyright © 2022 The Authors. The use of dynamic similitude has been widely proven in fluid mechanics. With the drive for efficient aircraft wing through high aspect ratio wings comes the growing need for much more accurate aeroelastic analyses of aircraft wings and more accurate scaled experimental tests. Even with this need for dynamic similitude in solid mechanics, there is still no unified exact scaling law applicable to any given solid structure or system. Here we present a recently proposed unified similitude model for solid mechanics using the momentum and the energy conservation. The model allows for the use of different materials in both elastic and plastic regimes. Never reported dimensionless numbers are derived for the first time in this article, and this set of numbers is sufficient for strictly accurate dynamic similitude of any solid structure. The application of the unified model is demonstrated for the first time in an aeroelastic structure and in aerospace structures through case studies. The very good agreement seen in compared results confirms the accuracy of the developed scaling model and the exactness of the dimensionless numbers

Syndromic (phenotypic) diarrhea in early infancy

Syndromic diarrhea (SD), also known as phenotypic diarrhea (PD) or tricho-hepato-enteric syndrome (THE), is a congenital enteropathy presenting with early-onset of severe diarrhea requiring parenteral nutrition (PN). To date, no epidemiological data are available. The estimated prevalence is approximately 1/300,000–400,000 live births in Western Europe. Ethnic origin does not appear to be associated with SD. Infants are born small for gestational age and present with facial dysmorphism including prominent forehead and cheeks, broad nasal root and hypertelorism. Hairs are woolly, easily removed and poorly pigmented. Severe and persistent diarrhea starts within the first 6 months of life (≤ 1 month in most cases) and is accompanied by severe malabsorption leading to early and relentless protein energy malnutrition with failure to thrive. Liver disease affects about half of patients with extensive fibrosis or cirrhosis. There is currently no specific biochemical profile, though a functional T-cell immune deficiency with defective antibody production was reported. Microscopic analysis of the hair show twisted hair (pili torti), aniso- and poilkilotrichosis, and trichorrhexis nodosa. Histopathological analysis of small intestine biopsy shows non-specific villous atrophy with low or no mononuclear cell infiltration of the lamina propria, and no specific histological abnormalities involving the epithelium. The etiology remains unknown. The frequent association of the disorder with parental consanguinity and/or affected siblings suggests a genetic origin with an autosomal recessive mode of transmission. Early management consists of total PN. Some infants have a rather milder phenotype with partial PN dependency or require only enteral feeding. Prognosis of this syndrome is poor, but most patients now survive, and about half of the patients may be weaned from PN at adolescence, but experience failure to thrive and final short stature

The role of salt abuse on risk for hypercalciuria

<p>Abstract</p> <p>Background</p> <p>Elevated sodium excretion in urine resulting from excessive sodium intake can lead to hypercalciuria and contribute to the formation of urinary stones. The aim of this study was to evaluate salt intake in patients with urinary lithiasis and idiopathic hypercalciuria (IH).</p> <p>Methods</p> <p>Between August 2007 and June 2008, 105 lithiasic patients were distributed into 2 groups: Group 1 (n = 55): patients with IH (urinary calcium excretion > 250 mg in women and 300 mg in men with normal serum calcium); Group 2 (n = 50): normocalciuric patients (NC). Inclusion criteria were: age over 18 years, normal renal function (creatinine clearance ≥ 60 ml/min), absent proteinuria and negative urinary culture. Pregnant women, patients with intestinal pathologies, chronic diarrhea or using corticoids were excluded. The protocol of metabolic investigation was based on non-consecutive collection of two 24-hour samples for dosages of: calcium, sodium, uric acid, citrate, oxalate, magnesium and urinary volume. Food intake was evaluated by the three-day dietary record quantitative method, and the Body Mass Index (BMI) was calculated and classified according to the World Health Organization (WHO). Sodium intake was evaluated based on 24-hour urinary sodium excretion.</p> <p>Results</p> <p>The distribution in both groups as regards mean age (42.11 ± 10.61 vs. 46.14 ± 11.52), weight (77.14 ± 16.03 vs. 75.99 ± 15.80), height (1.64 ± 0.10 vs. 1.64 <b>± plusorminus </b>0.08) and BMI (28.78 ± 5.81 vs. 28.07 ± 5.27) was homogeneous. Urinary excretion of calcium (433.33 ± 141.92 vs. 188.93 ± 53.09), sodium (280.08 ± 100.94 vs. 200.44.93 ± 65.81), uric acid (880.63 ± 281.50 vs. 646.74 ± 182.76) and magnesium (88.78 ± 37.53 vs. 64.34 ± 31.84) was significantly higher in the IH group (p < 0.05). There was no statistical difference in calcium intake between the groups, and there was significantly higher salt intake in patients with IH than in NC.</p> <p>Conclusions</p> <p>This study showed that salt intake was higher in patients with IH as compared to NC.</p

Purinergic receptors are part of a signalling system for proliferation and differentiation in distinct cell lineages in human anagen hair follicles

We investigated the expression of P2X5, P2X7, P2Y1 and P2Y2 receptor subtypes in adult human anagen hair follicles and in relation to markers of proliferation [proliferating cell nuclear antigen (PCNA) and Ki-67], keratinocyte differentiation (involucrin) and apoptosis (anticaspase-3). Using immunohistochemistry, we showed that P2X5, P2Y1 and P2Y2 receptors were expressed in spatially distinct zones of the anagen hair follicle: P2Y1 receptors in the outer root sheath and bulb, P2X5 receptors in the inner and outer root sheaths and medulla and P2Y2 receptors in living cells at the edge of the cortex/medulla. P2X7 receptors were not expressed. Colocalisation experiments suggested different functional roles for these receptors: P2Y1 receptors were associated with bulb and outer root sheath keratinocyte proliferation, P2X5 receptors were associated with differentiation of cells of the medulla and inner root sheaths and P2Y2 receptors were associated with early differentiated cells in the cortex/medulla that contribute to the formation of the hair shaft. The therapeutic potential of purinergic agonists and antagonists for controlling hair growth is discussed

Pathogenesis of pili annulati

Plucked scalp hairs and hair roots of pili annulati were examined to understand their pathogenesis. Stereoscopic examinations of hairs in transmitted light and/or reflected light and light microscopic surveys of the cross-sections of hairs confirmed that the cortical empty spaces appeared to be responsible to the unique dotted shiny appearance of the hairs seen by the unaided eyes under a refracted light. By transmission electron microscope, small vacuoles and dense bodies were observed in the cytoplasm of the differentiating cortical cells; subsequently, with increasing number of tonofilaments, an uneven distribution of free ribosomes occurred and abnormal spaces containing fine granular substances were formed in the cytoplasm of the cortical cells. Occasionally, extremely large cortical trichohyaline granules were found. In the keratinized hair, irregular empty spaces were present in the cortex of the abnormal hair segments. Histochemically, the keratinized cortex of the affected hairs always had more residual SH groups than the controls. Pili annulati may be a disorder of protein metabolism involving a partial dysfunction of cytoplasmic ribosomes, resulting in a lack of cortical keratin formation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47241/1/403_2004_Article_BF00440605.pd