Search results: Found 25

Listing 1 - 10 of 25 << page
of 3
>>
Sort by
Educational Mobility of Second-generation Turks: Cross-national Perspectives

Author:
ISBN: 9789089646514 Year: Pages: 280 Seiten DOI: 10.26530/OAPEN_496955 Language: Undetermined
Publisher: Amsterdam University Press
Subject: History --- Migration
Added to DOAB on : 2014-08-12 11:01:11
License:

Loading...
Export citation

Choose an application

Abstract

This volume investigates educational inequalities among children of Turkish immigrants in Austria, France, and Sweden. One of the largest immigrant groups in these countries, Turks nonetheless face discrimination and limited opportunities, and this study shows how those problems play out in education. One of its key findings is that systems that provide more favorable institutional arrangements lead to greater economic mobility in the second generation.

Inferior Colliculus Microcircuits

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193851 Year: Pages: 484 DOI: 10.3389/978-2-88919-385-1 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2015-12-03 13:02:24
License:

Loading...
Export citation

Choose an application

Abstract

The inferior colliculus (IC) is a unique structure in the auditory system, located between the primary auditory nuclei of the brainstem and the thalamus. The existence of the complex neural circuits in the auditory brainstem and midbrain, lacking in other sensory systems, has motivated an outpouring of research on the circuitry and physiological properties of the IC. IC neurons receive ascending inputs from over 20 separate sources in the brainstem as well as a dense collection of descending connections from the cortex. It is richly connected to both the left and right ears through these circuits and a major theme in research on the IC has been its role in binaural interactions. A second theme is the role of descending circuits in modulating responses to sound in the IC. A third theme is understanding the sound processing that occurs at the level of the IC, essentially how the representation of sound in the IC differs from that in the two auditory nerves. The representation of sound in the IC is an intermediate step in the development of the cortical representation as well as in the development of many perceptual features of sounds. These characteristics have been documented for a number of computations, including sound localization, masking properties, robustness of the representation, and responses to temporal and spectral properties of sounds. This Research Topic aims to discuss a wide range of aspects of the structure and function of the IC in a way that will facilitate future research.

The Coming of Age of Insulin-Signalling in Insects

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193141 Year: Pages: 138 DOI: 10.3389/978-2-88919-314-1 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
License:

Loading...
Export citation

Choose an application

Abstract

The new millennium has seen a major paradigm shift in insect endocrinology. Great advancements are being made which establish that nutrition and growth play a central role in diverse cellular and physiological phenomena during insect development and reproduction. Nutrition affects rates of growth and is mainly regulated by the function of the pathway of insulin/insulin-like growth factor signalling. This pathway is highly conserved across species and ultimately regulates rates of cell growth and proliferation in growing organs. Insulin and insulin-like peptides (ILPs) are some of the best studied hormones in the animal kingdom and all share a common structural motif and initiate a wide range of closely similar physiological processes in higher organisms. In insects, nutrition, via circulating sugar, promotes release of ILPs from brain neurosecretory cells into the haemolymph, which act on peripheral tissues and stimulate protein synthesis and cell growth. Therefore, insect ILPs are common mediators between nutrition and growth in insects and are functionally analogous to mammalian insulin. The 1980s and 1990s witnessed great progress in elucidation of the physiological and molecular mechanism of action of numerous insect hormones involved in regulation of growth, development, reproduction and metabolism. But the signals for the initiation or termination of controlled events remained largely unknown. ILPs were first identified from the silkmoth Bombyx mori and were named bombyxins, but related peptides were soon found in numerous species and their functions elucidated. The insulin signalling pathway is now recognized as a central factor in the timing of cell proliferation, growth, longevity, reproduction, and reproductive diapause, as well as social behaviour. Recent work has revealed that the insulin signalling pathway is closely integrated with that of various other hormones, including ecdysteroids, the juvenile hormones and neuropeptide(s) such a prothoracicotropic hormone. In addition, the pathway is also linked with both circadian (daily) and photoperiodic (seasonal) clocks potentially providing a basis for its timing function. This Research Topic aims to provide the only current collection of recent advances on insect ILPs. We encouraged submissions on all areas related to identification, characterization, regulation and physiological functions of insect ILPs. We welcomed both full and short reviews and original research articles.

Regulation of immune system cell functions by protein kinase C

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193264 Year: Pages: 129 DOI: 10.3389/978-2-88919-326-4 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-03-10 08:14:32
License:

Loading...
Export citation

Choose an application

Abstract

Members of the protein kinase C (PKC) family of Ser/Thr kinases are encoded by nine distinct but closely related genes, which give rise to more than 12 different protein isoforms via a mechanism of alternative RNA splicing. Most PKC proteins are ubiquitously expressed and participate in a plethora of functions in most cell types. A majority of PKC isoforms is also expressed in cells of the immune system in which they are involved in signal transduction downstream of a range of surface receptors, including the antigen receptors on T and B lymphocytes. PKC proteins are central to signal initiation and propagation, and to the regulation of processes leading to immune cell proliferation, differentiation, homing and survival. As a result, PKC proteins directly impact on the quality and quantity of immune responses and indirectly on the host resistance to pathogens and tendency to develop immune deficiencies and autoimmune diseases. A significant progress was made in recent years in understanding the regulation of PKC enzymes, their mechanism of action and their role in determining immunocyte behavior This volume reviews the most significant contributions made in the field of immune cell regulation by PKC enzymes. Several manuscripts are devoted to the role of distinct PKC isoforms in the regulation of selected immunocyte responses. Additional manuscripts review more general mechanisms of regulation of PKC enzymes, either by post-translational modifications, such as phosphorylation or controlled proteolysis, or by interaction with different binding proteins that may alter the conformation, activity and subcellular location of PKC. Both types of mechanisms can introduce conformational changes in the molecule, which may affect its ability to interact with cofactors, ATP, or substrates. This topic will be followed by a discussion on the positive and negative impact of individual PKC isoforms on cell cycle regulation. A second section of this volume concentrates on selected topics relevant to role of the novel PKC isoform, PKC-theta, in T lymphocyte function. PKC-theta plays important and some non-redundant roles in T cell activation and is a key isoform that recruits to the immunological synapse - the surface membrane area in T cells that comes in direct contact with antigen presenting cells. The immunological synapse is formed in T cells within seconds following the engagement of the TCR by a peptide-bound MHC molecule on the surface of antigen-presenting cells. It serves as a platform for receptors, adaptor proteins, and effector molecules, which assemble into multimolecular activation complexes required for signal transduction. The unique ability of PKC-theta to activate the NF-kB, AP-1 and NF-AT transcription factors is well established, and recent studies contributed essential information on the mechanisms involved in the recruitment of PKC-theta to the center of the immunological synapse and the nature of its substrates and the role of their phosphorylated forms in signal transduction. Additional review manuscripts will describe the unique behavior of PKC-theta in regulatory T cells and its role in the regulation of other cell populations, including those of the innate immune response. This volume brings together leading experts from different disciplines that review the most recent discoveries and offer new perspectives on the contributions of PKC isoforms to biochemical processes and signaling events in different immune cell populations and their impact on the overall host immune response.

Neurovision: Neural bases of binocular vision and coordination and their implications in visual training programs

Author:
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196555 Year: Pages: 264 DOI: 10.3389/978-2-88919-655-5 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2016-08-16 10:34:25
License:

Loading...
Export citation

Choose an application

Abstract

Binocular vision is achieved by five neurovisual systems originating in the retina but varying in their destination within the brain. Two systems have been widely studied: the retino-tectal or retino-collicular route, which subserves an expedient and raw estimate of the visual scene through the magnocellular pathway, and the retino-occipital or retino-cortical route, which allows slower but refined analysis of the visual scene through the parvocellular pathway. But there also exist further neurovisual systems: the retino-hypothalamic, retino-pretectal, and accessory optic systems, which play a crucial role in vision though they are less understood. The retino-pretectal pathway projecting onto the pretectum is critical for the pupillary or photomotor reflex. The retino-hypothalamic pathway projecting onto the suprachiasmatic nucleus regulates numerous behavioral and biological functions as well as circadian rhythms. The accessory optic system targeting terminal lateral, medial and dorsal nuclei through the paraoptic fasciculus plays a role in head and gaze orientation as well as slow movements. Taken together, these neurovisual systems involve 60% of brain activity, thus highlighting the importance of vision in the functioning and regulation of the central nervous system. But vision is first and foremost action, which makes perception impossible without movement. Binocular coordination is a prerequisite for binocular fusion of the object of interest on the two foveas, thus ensuring visual perception. The retino-collicular pathway is sufficient to elicit reflexive eye movements with short latencies. Thanks to its motor neurons, the superior colliculus activates premotor neurons, which themselves activate motor neurons of the oculomotor, trochlear and abducens nuclei. At a higher level, a cascade of neural mechanisms participates in the control of decisional eye movements. The superior colliculus is controlled by the substancia nigra pars reticulata, which is itself gated by subcortical structures such as the dorsal striatum. The superior colliculus is also inhibited by the dorsolateral prefrontal cortex through a direct prefrontotectal tract. Cortical areas are crucial for the triggering of eye movements: the frontal eye field, supplementary eye field, and parietal eye field. Finally the cerebellum maintains accuracy. The focus of the present research topic, entitled Neural bases of binocular vision and coordination and their implications in visual training programs, is to review the most recent findings in brain imaging and neurophysiology of binocular vision and coordination in humans and animals with frontally-placed eyes. The emphasis is put on studies that enable transfer of knowledge toward visual training programs targeting visual field defects (e.g., hemianopia) and binocular functional disorders (e.g., amblyopia).

Reelin-Related Neurological Disorders and Animal Models

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451111 Year: Pages: 179 DOI: 10.3389/978-2-88945-111-1 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
License:

Loading...
Export citation

Choose an application

Abstract

The Reeler mutation was so named because of the alterations in gait that characterize homozygous mice. Several decades after the description of the Reeler phenotype, the mutated protein was discovered and named Reelin (Reln). Reln controls a number of fundamental steps in embryonic and postnatal brain development. A prominent embryonic function is the control of radial neuronal migration. As a consequence, homozygous Reeler mutants show disrupted cell layering in cortical brain structures. Reln also promotes postnatal neuronal maturation. Heterozygous mutants exhibit defects in dendrite extension and synapse formation, correlating with behavioral and cognitive deficits that are detectable at adult ages. The Reln-encoding gene is highly conserved between mice and humans. In humans, homozygous RELN mutations cause lissencephaly with cerebellar hypoplasia, a severe neuronal migration disorder that is reminiscent of the Reeler phenotype. In addition, RELN deficiency or dysfunction is also correlated with psychiatric and cognitive disorders, such as schizophrenia, bipolar disorder and autism, as well as some forms of epilepsy and Alzheimer's disease. Despite the wealth of anatomical studies of the Reeler mouse brain, and the molecular dissection of Reln signaling mechanisms, the consequences of Reln deficiency on the development and function of the human brain are not yet completely understood. This Research Topic include reviews that summarize our current knowledge of the molecular aspects of Reln function, original articles that advance our understanding of its expression and function in different brain regions, and reviews that critically assess the potential role of Reln in human psychiatric and cognitive disorders.

Molecular and Biotechnological Advancements in Hypericum Species

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451173 Year: Pages: 159 DOI: 10.3389/978-2-88945-117-3 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Botany
Added to DOAB on : 2017-07-06 13:27:36
License:

Loading...
Export citation

Choose an application

Abstract

Hypericum is an important genus of the family Hypericaceae and includes almost 500 species of herbs, shrubs and trees. Being the home for many important bioactive compounds, these species have a long traditional value as medicinal plants. Currently, several species of this genus have been used in ailments as knowledge-based medicine in many countries. In the recent past, several pharmacological studies have been performed using crude extracts to evaluate the traditional knowledge. Results of those studies have revealed that Hypericum extract exert multiple pharmacological properties including antidepressant, antimicrobial, antitumor and wound healing effects. Phytochemical analyses revealed that these species produce a broad spectrum of valuable compounds, mainly naphthodianthrones (hypericin and pseudohypericin), phloroglucinols (hyperforin and adhyperforin), flavonoids (hyperoside, rutin and quercitrin), benzophenones/xanthones (garcinol and gambogic acid), and essential oils. Noticeably, Hypericum perforatum extracts have been used to treat mild to moderate depression from ancient to present times and the antidepressant efficacy of Hypericum extracts has been attributed to its hyperforin content, which is known to inhibit the re-uptake of aminergic transmitters such as serotonin and noradrenaline into synaptic nerve endings. Neurodegenerative diseases and inflammatory responses are also linked with Reactive Oxygen Species (ROS) production. A wide range of flavonoids present in Hypericum extracts, namely, rutin, quercetin, and quercitrin exhibit antioxidant/free radical scavenging activity. Hypericin, beside hyperforin, is the active molecule responsible for the antitumor ability of Hypericum extracts and is seen as a potent candidate to treat brain tumor. Recent attempts of using hypericin in patients with recurrent malignant brain tumors showed promising results. Collectively, Hypericum species contain multiple bioactive constituents, suggesting their potential to occupy a huge portion of the phytomedicine market. Today, studies on medicinal plants are rapidly increasing because of the search for new active molecules, and for the improvement in the production of plants and molecules for the herbal pharmaceutical industries. In the post genomic era, application of molecular biology and genomic tools revolutionized our understanding of major biosynthetic pathways, phytochemistry and pharmacology of Hypericum species and individual compounds. This special issue mainly focuses on the recent advancements made in the understanding of biosynthetic pathways, application of biotechnology, molecular biology, genomics, pharmacology and related areas.

The Impact of Systems Medicine on Human Health and Disease

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451401 Year: Pages: 96 DOI: 10.3389/978-2-88945-140-1 Language: English
Publisher: Frontiers Media SA
Subject: Physiology --- Neurology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
License:

Loading...
Export citation

Choose an application

Abstract

Complex diseases including diabetes, neurological disorders and cancer are results from a combination of genetic, environmental and lifestyle factors, and development of new prognostic tools for the treatment of such diseases requires a deep understanding of the mechanisms underlying cell functions. With the advances in high throughput technologies, biological components of cells can be measured with a very high resolution and these data can be used for investigating whole systems properties using a network-based approach. Systems medicine provides an integrative platform for studying the interactions between the biological components of the cell using a holistic approach and generating mechanistic explanations for the emergent systems properties. This inter-disciplinary field of study allows for understanding biological processes of cells in health and disease states, gaining new insights into what drives the appearance of the disease and finally identifying proteins and metabolites implicated in human disease. Systems medicine utilizes mathematical approaches to generate models which can be employed for designing new sets of experiments and for mapping the response of the system to perturbations quantitatively. These models, as well as the developed tools, can accelerate the emergence of personalized medicine which can transform the practice of medicine and offer better targets for drug development with minimum side effects. In this Research Topic, we aim to review the recently developed tools for modeling the cell behavior in normal and pathological states, recent advances and findings which increase our understanding of the molecular mechanisms involved in the progression of the diseases.

Signaling Pathways in Developing and Pathological Tissues and Organs of the Craniofacial Complex

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889456116 Year: Pages: 281 DOI: 10.3389/978-2-88945-611-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Physiology
Added to DOAB on : 2019-01-23 14:53:43
License:

Loading...
Export citation

Choose an application

Abstract

Head formation requires the well-orchestrated and harmonised development of various tissues and organs within the craniofacial complex. A big variety of signaling pathways are involved in this process by controlling cell proliferation, migration, differentiation, tissue morphogenesis, homeostasis and regeneration. Deregulation and malfunction of these signaling molecules may lead to mild or severe craniofacial pathologies. This eBook is a collection of articles dealing with a variety of important signals involved in the control of developmental and pathological events of craniofacial organs and tissues. These recent advances show the importance of signaling pathways in craniofacial physiology and pathology and generate important new knowledge aiming the development of new pharmaceutical products that mimic and/or block the actions of specific molecules.

Neuropeptide GPCRs in Neuroendocrinology

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192670 Year: Pages: 825 DOI: 10.3389/978-2-88919-267-0 Language: English
Publisher: Frontiers Media SA
Subject: Internal medicine --- Medicine (General) --- Neurology --- Science (General)
Added to DOAB on : 2015-12-03 13:02:24
License:

Loading...
Export citation

Choose an application

Abstract

The human genome encompasses ~ 860 G protein-coupled receptors (GPCRs) including 374 non-chemosensory GPCRs. Half of these latter GPCRs recognize (neuro)peptides as natural ligands. GPCRs thus play a pivotal role in neuroendocrine communication. In particular, GPCRs are involved in the neuroendocrine control of feeding behavior, reproduction, growth, hydromineral homeostasis and stress response. GPCRs are also major drug targets and hence possess a strong potential for the development of innovative pharmaceuticals. The aim of this Research Topic was to assemble a series of review articles and original research papers on neuropeptide GPCRs and their ligands that would illustrate the different facets of the studies currently conducted in this domain.

Listing 1 - 10 of 25 << page
of 3
>>
Sort by
Narrow your search