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Optomechatronics

ISBN: 9783038420019 9783038420088 Year: Pages: 276 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Added to DOAB on : 2016-05-20 15:03:42
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The field of optomechatronics provides synergistic effects of optics, mechanics and electronics for efficient sensor development. Optical sensors for the measurement of mechanical quantities, equipped with appropriate electronic signal (pre)processing means have a wide range of applications, from surface testing, stress monitoring, thin film analysis to biochemical sensing. The aim of this special issue is to provide an overview of actual research and innovative applications of optomechatronics in sensors. Papers addressing, inter alia, optical sensor principles, fiber-optic sensors, electronic speckle pattern interferometry, surface analysis, thin film measurement, FGB sensors, and biochemical sensors are provided.

Structure, function, and plasticity of hippocampal dentate gyrus microcircuits

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193875 Year: Pages: 133 DOI: 10.3389/978-2-88919-387-5 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2015-12-03 13:02:24
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The hippocampus mediates several higher brain functions, such as learning, memory, and spatial coding. The input region of the hippocampus, the dentate gyrus, plays a critical role in these processes. Several lines of evidence suggest that the dentate gyrus acts as a preprocessor of incoming information, preparing it for subsequent processing in CA3. For example, the dentate gyrus converts input from the entorhinal cortex, where cells have multiple spatial fields, into the spatially more specific place cell activity characteristic of the CA3 region. Furthermore, the dentate gyrus is involved in pattern separation, transforming relatively similar input patterns into substantially different output patterns. Finally, the dentate gyrus produces a very sparse coding scheme in which only a very small fraction of neurons are active at any one time. How are these unique functions implemented at the level of cells and synapses? Dentate gyrus granule cells receive excitatory neuron input from the entorhinal cortex and send excitatory output to the hippocampal CA3 region via the mossy fibers. Furthermore, several types of GABAergic interneurons are present in this region, providing inhibitory control over granule cell activity via feedback and feedforward inhibition. Additionally, hilar mossy cells mediate an excitatory loop, receiving powerful input from a small number of granule cells and providing highly distributed excitatory output to a large number of granule cells. Finally, the dentate gyrus is one of the few brain regions exhibiting adult neurogenesis. Thus, new neurons are generated and functionally integrated throughout life. How these specific cellular and synaptic properties contribute to higher brain functions remains unclear. One way to understand these properties of the dentate gyrus is to try to integrate experimental data into models, following the famous Hopfield quote: "Build it, and you understand it." However, when trying this, one faces two major challenges. First, hard quantitative data about cellular properties, structural connectivity, and functional properties of synapses are lacking. Second, the number of individual neurons and synapses to be represented in the model is huge. For example, the dentate gyrus contains ~1 million granule cells in rodents, and ~10 million in humans. Thus, full scale models will be complex and computationally demanding. In this Frontiers Research Topic, we collect important information about cells, synapses, and microcircuit elements of the dentate gyrus. We have put together a combination of original research articles, review articles, and a methods article. We hope that the collected information will be useful for both experimentalists and modelers. We also hope that the papers will be interesting beyond the small world of "dentology", i.e., for scientists working on other brain areas. Ideally, the dentate gyrus may serve as a blueprint, helping neuroscientists to define strategies to analyze network organization of other brain regions.

Regulation of Cell Fate Determination in Plants

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193240 Year: Pages: 84 DOI: 10.3389/978-2-88919-324-0 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-03-10 08:14:32
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Plants are made up of a large number of distinct cell types that originate from a single fertilized egg cell. How the diversity of cell types arise in appropriate places is one of the most fascinating and attractive research areas of plant biology. During the past several decades, due to the development of new molecular techniques and tools, advances in optical microscopy, and availability of whole genome information and mutants in the model plant Arabidopsis and other plants, great advances have been made in understanding the mechanisms involved in cell fate determination in plants. Multiple mechanisms are used to generate cellular diversity. Asymmetric cell division is one of the primary mechanisms. As an example, asymmetric cell division enables one stem cell to generate a stem cell daughter and a daughter with a distinct identity. Initially equivalent cells can also differentiate to generate different cell types. This mechanism has been clearly demonstrated in the formation of multiple cell types during epidermis development in the shoot and root. Cell fate determination is influenced by both intrinsic factors, i.e, developmental regulators, as well as extrinsic signals, i.e., environmental stimuli. By using model systems like stomata, trichome, root hair and shoot and root apical meristem cells, ligands, receptors and transcription factors have been found to regulate cell fate determination. However, the details of signaling cassettes responsible for cell fate determination remain largely unknown. Plants are made up of a large number of distinct cell types that originate from a single fertilized egg cell. How the diversity of cell types arise in appropriate places is one of the most fascinating and attractive research areas of plant biology. During the past several decades, due to the development of new molecular techniques and tools, advances in optical microscopy, and availability of whole genome information and mutants in the model plant Arabidopsis and other plants, great advances have been made in understanding the mechanisms involved in cell fate determination in plants. This research topic contains 12 collected articles, including 2 Opinion Articles, 5 Reviews, 4 Mini Reviews, and 1 Original Research Article. Hopefully, these articles will expand our understanding of the regulation of cell fate determination in plants.

Nutrition and Celiac Disease

ISBN: 9783906980638 9783906980645 Year: Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Added to DOAB on : 2015-01-12 11:28:32
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During its 2.5 million years of evolution, the human species has evolved through major dramatic changes, mainly dictated by natural elements and, most importantly, by food availability. The diet of hunters and gatherers, hominids, was mainly based on fruit, vegetables, tubers, and occasionally meat and fish. Then, approximately 10,000 years ago, a drastic change in life style occurred, shifting from nomadic to settlers with domestication of animals and crops. A consequence of this change was the advent of wheat and other grains containing gluten-related proteins in human diet. This revolutionary transformation occurred at the Fertile Crescent, the modern-day Iraq, and spread from South to North and East to West at a speed of approximately 1 km/year. Ever since, the distribution of food goods became more and more uneven with wealthy countries getting more than necessary, while poor countries struggle with malnutrition and consequently this increased mortality. Unfortunately, the industrial revolution, rather than closing the gap, created even more inequalities that still exist today, leading to very different but equally worrisome pathologies, namely obesity in industrialized countries and famine in developing countries. [...]

Beitrag zur Vorbemessung der Biegeverstärkung von Stahlbetonbauteilen mit Rechteckquerschnitt mittels aufgeklebten CFK-Lamellen

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ISBN: 9783966270021 9783966270038 9783966270007 9783966270014 Year: Pages: 252 DOI: 10.33968/9783966270021-00 Language: German
Publisher: HTWK Leipzig - OA-Hochschulverlag
Subject: Agriculture (General)
Added to DOAB on : 2020-02-12 11:21:04
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"Since 2012, the subsequent reinforcement of reinforced concrete components with bonded reinforcement has been regulated in a separate guideline. This includes the dimensioning of the adhesively bonded strips made of carbon fiber reinforced plastic (CFRP), which, in addition to the complex iterative bending design, have a very complex bonding behavior. For this purpose, the German Committee for Structural Concrete developed a model for the verification based on experimental evaluations, in which the occurring tensile forces are partly transferred into the component via intermediate elements (partial distances between flexural cracks). Simultaneously, simplified but more inaccurate verification formats were made available to reduce the complexity of the verification. For an early assessment of the use of bonded CFRP strips, different tools have been developed in this paper for reinforced concrete components with a rectangular cross-section depending on the different verification formats. For this purpose, the design parameters were considered separately for pure bending strength and bonding behavior. For a simple calculation, tables for the design with dimensionless coefficients were obtained by analogy with the reinforced concrete construction, with which the required cross-section area for the CFRP strips can be determined by means of a limited stretching from the simplified verification of the flexural load bearing capacity. For a more economical solution, the more precise verification of the force transmission on the intermediate elements was configured in an Excel workbook, because this results in an extraordinary iterative calculation effort."

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