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Thymic stromal alterations and genetic disorders of immune system

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197170 Year: Pages: 81 DOI: 10.3389/978-2-88919-717-0 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-04-07 11:22:02
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The pathogenic mechanisms underlying primary T-cell disorders are mainly related to molecular alterations of genes whose expression is intrinsic to hematopoietic cells. However, since the differentiation process requires a crosstalk among thymocytes and the thymic microenvironment, molecular alterations of genes, involved in the differentiation and functionality of the stromal component of the thymus, may lead to a severe T-cell defect or failure of central tolerance, as well. The first example of severe combined immunodeficiency (SCID) not related to an intrinsic alteration of the hematopoietic cell but rather of the thymic epithelial component is the Nude/SCID phenotype, inherited as an autosomal recessive disorder, whose hallmarks are the T-cell defect and the absence of the thymus. The clinical and immunological phenotype is the human equivalent of the murine Nude/SCID syndrome, which represents the first spontaneous SCID identified in nude mice in 1966. For over 3 decades studies of immune system in these mice enormously contributed to the overall knowledge of cell mediated immunity, in the assumption that the athymia of these mice was solely responsible for the T-cell immunological defect. This syndrome is due to mutations of the transcription factor FOXN1, belonging to the forkhead-box gene family, which is mainly expressed in the thymus and skin epithelial cells, where it plays a critical role in differentiation and survival. An alteration of the thymic structure is also a feature of the DiGeorge syndrome (DGS), which has been long considered the human counterpart of the nude mice phenotype. This syndrome is frequently associated to a deletion of the 22q11 region, which contains approximately 30 genes, including the TBX1 gene, which is responsible for most of the clinical features of DGS in humans and mice. In this syndrome common manifestations are cardiac malformations, speech delay, hypoparathyrodism and immunodeficiency, even though the immunological hallmarks of the T-cell defect in DiGeorge syndrome are profoundly different from those reported in human Nude/SCID. The divergence of the phenotype among these 2 entities raised the possibility that the FOXN1 transcription factor represents the real key stromal molecule implicated in directing the hematopoietic stem cell toward a proper T-cell fate. Thymic stromal component of the primary lymphoid organ is also required to negatively select the autoreactive clones, a process driven by the expression of tissue specific antigens (TSA) by medullary thymic epithelial cells (mTECs). The expression of genes encoding TSA antigens is mediated by autoimmune regulator (AIRE) gene, encoding a transcription factor expressed in mTECs. Molecular alterations of this gene are associated to autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a rare autosomal disorder, which may be considered the prototype of an autoimmune disease due to the failure of central tolerance homeostasis. All these "experiments of nature" led to unravel novel pathogenic mechanisms underlying inherited disorders of immune system and, of note, to clarify the pivotal role of epithelial cells in the maturation and education process of T-cell precursors.

Neuro-Development and Psychological Issues in Congenital Heart Defects

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454280 Year: Pages: 87 DOI: 10.3389/978-2-88945-428-0 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Pediatrics
Added to DOAB on : 2018-11-16 17:17:57
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The advances in the peri-operative management of congenital heart defects have substantially improved the survival of infants over the last few decades, reaching >95% survival in the reports of the international congenital data-base from the European Association of Cardio-Thoracic Surgery and form the Society of Thoracic Surgery (North-America).Nevertheless, the surviving children often experience neurodevelopmental deficits and behavioral, emotional and social issues. These problems often have a profound impact on the quality of life of the growing population of these children at risk and their families.

Modelling the human cardiac fluid mechanics

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ISBN: 3937300821 Year: Pages: 49 p. DOI: 10.5445/KSP/1000003551 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:01:58
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We present a virtual heart model simulating the flow in the left human ventricle and in the aorta. Because of the lack of in vivo structure data of the human ventricle, the active ventricle movement is given by a time-dependent ventricle model that is derived from in vivo image data of a nuclear spin MRT tomograph of a healthy human heart. The passive part of the virtual heart model consists of a model aorta and vena cava, and of heart valves. As the movement is due to the flow in the inactive region of the heart, a coupling of flow and structure is necessary in the model to take into account the deviation of the aorta and the closing and opening of the heart valves. The flow calculation is performed with a finite volume method, while the structure of the aorta is calculated using the finite element method. The flow resistance of the time simulation in the body is taken into account with a circulation model. In the outlook of the article, we show how the virtual heart model can be used to predict flow losses due to pathological ventricle contraction defects in an unhealthy human heart.

Bemessung von Erzeugnissen aus Stahlguss unter vorwiegend ruhender Beanspruchung

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Book Series: Berichte zum Stahl- und Leichtbau / Karlsruher Institut für Technologie, Versuchsanstalt für Stahl, Holz und Steine, Stahl- und Leichtbau ISSN: 21987912 ISBN: 9783731505600 Year: Volume: 5 Pages: XVIII, 210 p. DOI: 10.5445/KSP/1000057630 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:01
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Since the internal condition directly influences the calculated component resistance by using cast steel, the requirement of a quality grade already has to be determined during the design and planning phase. However, there is currently no decision-making on the selection of a quality level depending on the load. Therefore, two design concepts are developed for the load-bearing capacity of steel castings depending on the grades.

Liquid Crystals: From Modified Phases to Applications 2014

ISBN: 9783906980850 9783906980867 Year: Pages: 320
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Added to DOAB on : 2015-10-22 06:24:45
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Liquid crystals can be found in both synthetic and natural materials, which include DNA, cellulose, soaps, and cholesteryl esters. Liquid crystal basic concepts are an inspiration for various branches of physics, chemistry, materials science, mathematics, biology, and engineering. These concepts enable the synthesis and characterization of new materials with low-molecular weight, as well as of polymeric and elastomeric materials. Fundamental theories and models of liquid crystals have gained great importance in many scientific communities. The concepts of orientational order and cooperative molecular behavior have entered the actual basic knowledge of the bio-sciences community, and have contributed to the understanding of muscle function, cell division and membranes, and morphogenesis.Recent trends in liquid crystal research include topics such as polymer-modified anisotropic fluids, dispersions of liquid crystals with various nano-sized particles, topological defects in soft materials, new lyotropic systems, liquid crystal functionality in living systems, and the synthesis of liquid crystal based functional materials (e.g., photonic materials, organic plastic conductors, semiconductors, materials in sensors, materials used in switchable GHz applications, and materials for data storage), along with the study of these materials’ properties and applications.

Titanium Dioxide Photocatalysis

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ISBN: 9783038976943 / 9783038976950 Year: Pages: 208 DOI: 10.3390/books978-3-03897-695-0 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Chemistry (General)
Added to DOAB on : 2019-06-26 08:44:06
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Although the seminal work of Fujishima et al. dates back to 1971, TiO2 still remains the most diffused and studied semiconductor, employed in photo-oxidation processes for cleantech (i.e., polluted water and air treatment), in solar fuel production (mainly hydrogen production by water photo splitting), and in Carbon Capture and Utilization (CCU) processes by CO2 photoreduction. The eleven articles, among them three reviews, in this book cover recent results and research trends of various aspects of titanium dioxide photocatalysis, with the chief aim of improving the final efficiency of TiO2-based materials. Strategies include doping, metal co-catalyst deposition, and the realization of composites with plasmonic materials, other semiconductors, and graphene. Photocatalysts with high efficiency and selectivity can be also obtained by controlling the precise crystal shape (and homogeneous size) and the organization in superstructures from ultrathin films to hierarchical nanostructures. Finally, the theoretical modeling of TiO2 nanoparticles is discussed and highlighted. The range of topics addressed in this book will stimulate the reader’s interest as well as provide a valuable source of information for researchers in academia and industry.

Neonatal Screening for Critical Congenital Heart Defects

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ISBN: 9783039210480 / 9783039210497 Year: Pages: 98 DOI: 10.3390/books978-3-03921-049-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Social Sciences --- Sociology
Added to DOAB on : 2019-06-26 08:44:06
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Critical congenital heart defects (CCHDs) are potentially life-threatening malformations that remain a significant cause of neonatal mortality and morbidity. Failure to diagnose these conditions shortly after birth may result in acute cardiovascular collapse and death. The identification of CCHDs by routine newborn clinical examination is routine in many countries, but consistently misses over a third of cases, and, although antenatal ultrasound screening can be very effective in early diagnosis, the provision and accuracy of ultrasound screening is highly variable. As most CCHDs present with mild cyanosis (hypoxaemia), which is frequently clinically undetectable, pulse oximetry is a rapid, simple, painless method of accurately identifying hypoxaemia, which has gained popularity as a screen for CCHD. This Special Issue of the International Journal of Neonatal Screening, devoted to ""Neonatal Screening for Critical Congenital Heart Defects (CCHDs)"", will consider the evidence for CCHD screening with pulse oximetry, the acceptability and cost-effectiveness of this intervention, the additional non-cardiac conditions which it may also identify, and international experiences of introducing CCHD screening across the globe.

Crystal Chemistry of Zinc, Cadmium and Mercury

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ISBN: 9783038976523 Year: Pages: 156 DOI: 10.3390/books978-3-03897-653-0 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Organic Chemistry --- Chemistry (General) --- Science (General)
Added to DOAB on : 2019-04-05 10:34:31
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This book is a printed edition of the Special Issue Crystal Chemistry of Zinc, Cadmium and Mercury that was published in Crystals

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