Histochemistry and functional organization of the dorsal skin of Ancistrus dolichopterus (Siluriformes: Loricariidae)

The structural organization and histo-cytochemical features of dorsal skin of Ancistrus dolichopterus (acari bodo) are the main focus of this work. The epidermis, dermis and subcutis are the principal layers of the skin. The epidermis mainly consists of epithelial and mucous cells. Interspersed between them are lymphocytes, pigment cells, eosinophilic granular cells (EGC), and the taste buds as sensory structures. The high number of EGCs is implicated in general and specific immunological defense from pathogenic bacteria and multicellular parasites. The epithelial cells and mucous cells contain glycoproteins with oxidizable vicinal diols, carboxyl groups and O-sulphate esters and their high secretory activity is correlated with the bottom dwelling habit of this species. A thick stratum laxum contains overlapping osteoderms bearing denticles, and the stratum compactum make the integument thicker to help the fish in negative buoyancy for maneuvering near the bottom and protection. The entire body surface is covered by conical, backwardly directed denticles. These are composed of a dentine cone, surrounding a pulp cavity with the top covered by mineralized cap, and are the true homologues of teeth. These structures provide effective protection from abrasion and enemies. These structural peculiarities and histochemical features indicate additional physiological role of the skin of A. dolichopterus. © 2010 Sociedade Brasileira de Ictiologia

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Free vibration of sandwich laminates with two higher-order shear deformable facet shell element models

Two higher-order shear deformable finite element models using a higher-order facet shell element are presented for the free vibration analysis of layered anisotropic sandwich laminates. One of the higher-order shear deformation models accounts for the effects of both transverse shear strains/stresses and the transverse normal strain/stress, while the other includes only the effects of the transverse shear deformation. The accuracy of the present models is demonstrated by comparing the results of laminated sandwich plates with the available closed- form solutions. Benchmark solutions with the parametric study for the laminated sandwich cylindrical and spherical shell panels are also presented

Closed-form thermo-mechanical solutions of higher-order theories of cross-ply laminated shallow shells

Closed-form formulations of 2D higher-order shear deformation theories for the thermo-mechanical analysis of simply supported doubly curved cross-ply laminated shells are presented. Formulation includes the Sander’s theory for doubly curved shells. Two of the higher-order shear deformation theories account for the effects of both transverse shear strains/stresses and the transverse normal strain/stress, while the third includes only the effects of the transverse shear deformation. In these developments a realistic parabolic distribution of transverse shear strains through the shell thickness is assumed. The temperature variation considered in the formulation is uniform or sinusoidal over the surface and linearly varying through the thickness. Numerical results are presented for thermal and mechanical load cases in laminated composite and sandwich shallow shells. The closed-form solutions presented herein for laminated composite plate or shells are compared with the available 3D elasticity solutions for mechanical loading and it is believed that solutions for thermal loading will serve as bench mark in future.© Elsevie

Free vibration of composite and sandwich laminates with a higher-order facet shell element

A simple C0isoparametric finite element formulation based on a shear deformable model of higher-order theory using a higher-order facet shell element is presented for the free vibration analysis of isotropic, orthotropic and layered anisotropic composite and sandwich laminates. This theory incorporates a realistic non-linear variation of displacements through the shell thickness, and eliminates the use of shear correction coefficients. The validity and efficiency of the present formulation is established by obtaining solutions to a wide range of problems and comparing them with the available three-dimensional closed-form and finite element solutions. In addition, other plate and shell solutions of different kind and available in the literature are also compiled and tabulated for the sake of completeness. The parametric effects of degree of orthotropy, length-to-thickness ratio, plate aspect ratio, number of layers and fibre orientation upon the frequencies and mode shapes are discussed.© Elsevie

AN EFFICIENT MATHEMATICAL MODELING FOR THE COMPREHENSIVE DESIGN OF AON INCLUDING WAVELENGTH ASSIGNMENT SCHEME

This paper recommends a systematic wavelength assignment scheme which deliberately enhance the quality of service by minimizing the average dispersion in optical network. In this approach assignment of the wavelength recommended that allocates the wavelength as per mathematical model based on the path length request. Results validate that path length-based scheme improves the system performance in comparison with the commonly used existing assignment technique which works on the principle of first fit wavelength assignment(FFWA) and former assignment methodology should be ideal choice when the number of connection requests extremely high