VISCOUS DAMAGE MODEL FOR TIMOSHENKO BEAM STRUCTURES

A local damage constitutive model based on Kachanov’s theory is used within a finite element frame and applied to the case of 2D and 3D Timoshenko beam elements. The model takes into account viscous effects, thus allowing damping to be considered in a rigorous way. A damage index based on potential energy criteria, useful in evaluating the behaviour of structures or of parts of structures, is proposed. The procedure is applied to estimate the damage produced by seismic actions in reinforced concrete building structures, whose response is computed by using a non-linear Newmark-type incremental time integration scheme. Three numerical examples are included; one of them compares results obtained by using the proposed model with results of a laboratory test. &nbsp

The experience of pediatric surgery clinic in the treatment of hemangiomas and vascular malformations

Universitatea de Medicină şi Farmacie “Grigore T. Popa”, Clinica de Chirurgie şi Ortopedie Pediatrică a Spitalului Clinic de Urgenţă pentru Copii "Sfânta Maria", Iaşi, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroducere: Afecţiunile congenitale vasculare includ tumorile vasculare (hemangioamele infantile, hemangioendoteliomul caposiform, hemangioame non-involutive, hemangioame rapid-involutive) şi malformaţii vasculare (capilare, venoase, limfatice, arteriovenoase şi mixte). Hemangioamele sunt cele mai frecvente tumori benigne vasculare în populaţia pediatrică iar localizarea lor poate fi unică – extremitate cefalică (60%), trunchi (25%) sau multiplă, impunând extinderea investigaţiilor pentru interesarea viscerală (hemangioame hepatice, intestinale, splenice, intracraniene, renale). Malformaţiile capilare apar ca leziuni singulare sau în asociere în cadrul altor afecţiuni – sindrom Struge-Weber, sindrom Klippel-Trenaunay. Cunoscute în trecut ca limfangioame, malformaţiile limfatice sunt clasificate acum ca fiind microcistice, macrocistice (localizate mai frecvent la nivelul capului şi gâtului) sau mixte. Material și metode: Lucrarea prezintă cazuri de hemangioame din colecţia clinicii, aspectul lor clinic şi evoluţia sub terapie cu un beta-blocant. Experienţa Clinicii de Chirurgie Pediatrică Iaşi privind utilizarea Propranololului datează din 2011 şi se datorează participării într+un studiu internaţional multicentric dublu-orb randomizat privind eficienţa şi siguranţa utilizării mai multor scheme de betablocant în tratamentul hemangioamelor infantile. Acest studiu a condus la aprobarea produsului Hemangiol de către Agenţia Europeană a Medicamentelor (EMA). Rezultate și concluzii: Hemangioamele au un prognostic bun, cu 98% rata de răspuns la administrarea de Propranolol.Introduction: The vascular congenital disorders include vascular tumor (hemangioma, kaposiform hemangioendothelioma, tufted hemangioma, non-involuting congenital hemangioma, rapidly-involuting congenital hemangioma) and vascular malformation (capillary, venous, lymphatic, arteriovenous and mixed malformations). Hemangiomas are the most common benign vascular tumors in the pediatric age and their localization may be unique – head (60%) and trunk (25%) or multiple, requiring extensive investigations for visceral involvement (hepatic, intestinal, splenic, intracranial, renal). Capillary malformations occur as isolated lesions or in association with other disorders – Struge-Weber syndrome, Klippel-Trenaunay syndrome. Lymphatic malformations, previously known as lymphangiomas are classified as microcystic, macrocystic (often present on the head and neck) or mixed. Material and methods: The paper presents cases of hemagiomas on the clinic’s collection, their clinical aspects and evolution under the pharmacotherapy with a beta-blocker. The experience of the Pediatric Surgery Clinic in Iasi regarding the use of Propranolol dates back to 2011 and is due to participation in a randomized, double-blind, multi-center international study on the safety and efficiency of betablockers in the treatment of infantile hemangiomas. The study led to the approval of Hemangiol by EMA (European Medicines Agency). Results and conclusions: Hemangiomas have a good prognosis with a 98% response to Propranolol administration

Gray matter injury associated with periventricular leukomalacia in the premature infant

Neuroimaging studies indicate reduced volumes of certain gray matter regions in survivors of prematurity with periventricular leukomalacia (PVL). We hypothesized that subacute and/or chronic gray matter lesions are increased in incidence and severity in PVL cases compared to non-PVL cases at autopsy. Forty-one cases of premature infants were divided based on cerebral white matter histology: PVL (n = 17) with cerebral white matter gliosis and focal periventricular necrosis; diffuse white matter gliosis (DWMG) (n = 17) without necrosis; and

Gray Matter Changes in Parkinson's and Alzheimer's Disease and Relation to Cognition

Purpose of Review We summarize structural (s)MRI findings of gray matter (GM) atrophy related to cognitive impairment in Alzheimer's disease (AD) and Parkinson's disease (PD) in light of new analytical approaches and recent longitudinal studies results. Recent Findings The hippocampus-to-cortex ratio seems to be the best sMRI biomarker to discriminate between various AD subtypes, following the spatial distribution of tau pathology, and predict rate of cognitive decline. PD is clinically far more variable than AD, with heterogeneous underlying brain pathology. Novel multivariate approaches have been used to describe patterns of early subcortical and cortical changes that relate to more malignant courses of PD. New emerging analytical approaches that combine structural MRI data with clinical and other biomarker outcomes hold promise for detecting specific GM changes in the early stages of PD and preclinical AD that may predict mild cognitive impairment and dementia conversion

Developmental Hippocampal Neuroplasticity in a Model of Nicotine Replacement Therapy during Pregnancy and Breastfeeding

The influence of developmental nicotine exposure on the brain represents an important health topic in light of the popularity of nicotine replacement therapy (NRT) as a smoking cessation method during pregnancy.In this study, we used a model of NRT during pregnancy and breastfeeding to explore the consequences of chronic developmental nicotine exposure on cerebral neuroplasticity in the offspring. We focused on two dynamic lifelong phenomena in the dentate gyrus (DG) of the hippocampus that are highly sensitive to the environment: granule cell neurogenesis and long-term potentiation (LTP).Pregnant rats were implanted with osmotic mini-pumps delivering either nicotine or saline solutions. Plasma nicotine and metabolite levels were measured in dams and offspring. Corticosterone levels, DG neurogenesis (cell proliferation, survival and differentiation) and glutamatergic electrophysiological activity were measured in pups.Juvenile (P15) and adolescent (P41) offspring exposed to nicotine throughout prenatal and postnatal development displayed no significant alteration in DG neurogenesis compared to control offspring. However, NRT-like nicotine exposure significantly increased LTP in the DG of juvenile offspring as measured in vitro from hippocampal slices, suggesting that the mechanisms underlying nicotine-induced LTP enhancement previously described in adult rats are already functional in pups.These results indicate that synaptic plasticity is disrupted in offspring breastfed by dams passively exposed to nicotine in an NRT-like fashion

C-Terminus Glycans with Critical Functional Role in the Maturation of Secretory Glycoproteins

The N-glycans of membrane glycoproteins are mainly exposed to the extracellular space. Human tyrosinase is a transmembrane glycoprotein with six or seven bulky N-glycans exposed towards the lumen of subcellular organelles. The central active site region of human tyrosinase is modeled here within less than 2.5 Å accuracy starting from Streptomyces castaneoglobisporus tyrosinase. The model accounts for the last five C-terminus glycosylation sites of which four are occupied and indicates that these cluster in two pairs - one in close vicinity to the active site and the other on the opposite side. We have analyzed and compared the roles of all tyrosinase N-glycans during tyrosinase processing with a special focus on the proximal to the active site N-glycans, s6:N337 and s7:N371, versus s3:N161 and s4:N230 which decorate the opposite side of the domain. To this end, we have constructed mutants of human tyrosinase in which its seven N-glycosylation sites were deleted. Ablation of the s6:N337 and s7:N371 sites arrests the post-translational productive folding process resulting in terminally misfolded mutants subjected to degradation through the mannosidase driven ERAD pathway. In contrast, single mutants of the other five N-glycans located either opposite to the active site or into the N-terminus Cys1 extension of tyrosinase are temperature-sensitive mutants and recover enzymatic activity at the permissive temperature of 31°C. Sites s3 and s4 display selective calreticulin binding properties. The C-terminus sites s7 and s6 are critical for the endoplasmic reticulum retention and intracellular disposal. Results herein suggest that individual N-glycan location is critical for the stability, regional folding control and secretion of human tyrosinase and explains some tyrosinase gene missense mutations associated with oculocutaneous albinism type I

Language development after cochlear implantation: an epigenetic model

Growing evidence supports the notion that dynamic gene expression, subject to epigenetic control, organizes multiple influences to enable a child to learn to listen and to talk. Here, we review neurobiological and genetic influences on spoken language development in the context of results of a longitudinal trial of cochlear implantation of young children with severe to profound sensorineural hearing loss in the Childhood Development after Cochlear Implantation study. We specifically examine the results of cochlear implantation in participants who were congenitally deaf (N = 116). Prior to intervention, these participants were subject to naturally imposed constraints in sensory (acoustic–phonologic) inputs during critical phases of development when spoken language skills are typically achieved rapidly. Their candidacy for a cochlear implant was prompted by delays (n = 20) or an essential absence of spoken language acquisition (n = 96). Observations thus present an opportunity to evaluate the impact of factors that influence the emergence of spoken language, particularly in the context of hearing restoration in sensitive periods for language acquisition. Outcomes demonstrate considerable variation in spoken language learning, although significant advantages exist for the congenitally deaf children implanted prior to 18 months of age. While age at implantation carries high predictive value in forecasting performance on measures of spoken language, several factors show significant association, particularly those related to parent–child interactions. Importantly, the significance of environmental variables in their predictive value for language development varies with age at implantation. These observations are considered in the context of an epigenetic model in which dynamic genomic expression can modulate aspects of auditory learning, offering insights into factors that can influence a child’s acquisition of spoken language after cochlear implantation. Increased understanding of these interactions could lead to targeted interventions that interact with the epigenome to influence language outcomes with intervention, particularly in periods in which development is subject to time-sensitive experience

The peatland map of Europe

Based on the ‘European Mires Book’ of the International Mire Conservation Group (IMCG), this article provides a composite map of national datasets as the first comprehensive peatland map for the whole of Europe. We also present estimates of the extent of peatlands and mires in each European country individually and for the entire continent. A minimum peat thickness criterion has not been strictly applied, to allow for (often historically determined) country-specific definitions. Our ‘peatland’ concept includes all ‘mires’, which are peatlands where peat is being formed. The map was constructed by merging national datasets in GIS while maintaining the mapping scales of the original input data. This ‘bottom-up’ approach indicates that the overall area of peatland in Europe is 593,727 km². Mires were found to cover more than 320,000 km² (around 54 % of the total peatland area). If shallow-peat lands (< 30 cm peat) in European Russia are also taken into account, the total peatland area in Europe is more than 1,000,000 km2, which is almost 10 % of the total surface area. Composite inventories of national peatland information, as presented here for Europe, may serve to identify gaps and priority areas for field survey, and help to cross-check and calibrate remote sensing based mapping approaches