Glial Cells in Health and Disease of the CNS

Download Glial Cells in Health and Disease of the CNS PDF Online Free

Author :
Publisher : Springer
ISBN 13 : 3319407643
Total Pages : 348 pages
Book Rating : 4.3/5 (194 download)

DOWNLOAD NOW!


Book Synopsis Glial Cells in Health and Disease of the CNS by : Rommy von Bernhardi

Download or read book Glial Cells in Health and Disease of the CNS written by Rommy von Bernhardi and published by Springer. This book was released on 2016-10-06 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: A timely overview covering the three major types of glial cells in the central nervous system - astrocytes, microglia, and oligodendrocytes. New findings on glia biology are overturning a century of conventional thinking about how the brain operates and are expanding our knowledge about information processing in the brain. The book will present recent research findings on the role of glial cells in both healthy function and disease. It will comprehensively cover a broad spectrum of topics while remaining compact in size.

The Functional Roles of Glial Cells in Health and Disease

Download The Functional Roles of Glial Cells in Health and Disease PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1461546850
Total Pages : 376 pages
Book Rating : 4.4/5 (615 download)

DOWNLOAD NOW!


Book Synopsis The Functional Roles of Glial Cells in Health and Disease by : Rebecca Matsas

Download or read book The Functional Roles of Glial Cells in Health and Disease written by Rebecca Matsas and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thirty-five years ago, when Stephen Kuffler and his colleagues at Harvard initiated a new era of research on the properties and functions of neuroglial cells, very few neuro scientists were impressed at the time with the hypothesis that neuroglial cells could have another, though more subtle, role to play in the nervous system than to provide static support to neurons. Today, very few neuroscientists are unaware of the fact that multiple interactions between neurons and glial cells have been described, and that they consti tute the basis for understanding the function and the pathology of the nervous system. Glial cells outnumber neurons and make up about one-half of the bulk of the nervous system. They are divided into two major classes: first, the macroglia, which include astrocytes and oligodendrocytes in the central nervous system, and the Schwann cells in the peripheral nervous system; and second, the microglial cells. These different classes of glial cells have different functions and contribute in different ways in the devel opment, function, and the pathology of the nervous system.

Microglia in Health and Disease

Download Microglia in Health and Disease PDF Online Free

Author :
Publisher : Springer
ISBN 13 : 1493914294
Total Pages : 486 pages
Book Rating : 4.4/5 (939 download)

DOWNLOAD NOW!


Book Synopsis Microglia in Health and Disease by : Marie-Ève Tremblay

Download or read book Microglia in Health and Disease written by Marie-Ève Tremblay and published by Springer. This book was released on 2014-09-22 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: These past few years have witnessed a revolution in our understanding of microglia, especially since their roles in the healthy central nervous system (CNS) have started to unravel. These cells were shown to actively maintain health, in concert with neurons and other types of CNS cells, providing further insight into their involvement with diseases. Edited by two pioneers in the field, Marie-Ève Tremblay and Amanda Sierra, Microglia in health and disease aims to share with the broader scientific community some of the recent discoveries in microglia research, from a broad perspective, with a collection of 19 chapters from 52 specialists working in 11 countries across 5 continents. To set microglia on the stage, the book begins by explaining briefly who they are, what they do in the healthy and diseased CNS, and how they can be studied. The first section describes in more details their physiological roles in the maturation, function, and plasticity of the CNS, across development, adolescence, adulthood, neuropathic pain, addiction, and aging. The second section focuses on their implication in pathological conditions impairing the quality of life: neurodevelopmental and neuropsychiatric disorders, AIDS, and multiple sclerosis; and in leading causes of death: ischemia and stroke, neurodegenerative diseases, as well as trauma and injury.

The Biology of Glial Cells: Recent Advances

Download The Biology of Glial Cells: Recent Advances PDF Online Free

Author :
Publisher : Springer Nature
ISBN 13 : 9811683131
Total Pages : 763 pages
Book Rating : 4.8/5 (116 download)

DOWNLOAD NOW!


Book Synopsis The Biology of Glial Cells: Recent Advances by : Ishan Patro

Download or read book The Biology of Glial Cells: Recent Advances written by Ishan Patro and published by Springer Nature. This book was released on 2022-04-09 with total page 763 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the role of glial cells (astrocytes, microglia, oligodendroglia, satellite cells, and Schwann cells) in neuronal health and diseases. It discusses the latest advances in understanding their origin, differentiation, and hemostasis. The book also examines the role of microglial cells in central nervous system (CNS) development, maintenance, and synaptic plasticity. Further, the book presents the functions of astrocytes in healthy CNS and their critical role in CNS disorders, including Parkinson's and Alzheimer's diseases. Notably, the book describes the pathobiology, molecular pathogenesis, stem cells, and imaging characteristics of gliomas. It defines the role of glial cells in regulating iron homeostasis and their effect on the neurodegeneration of neurons. Lastly, it covers the structure, function, and pathology of oligodendrocytes and their role in neuronal health and disease. ​

Glia in Health and Disease

Download Glia in Health and Disease PDF Online Free

Author :
Publisher : BoD – Books on Demand
ISBN 13 : 1789852536
Total Pages : 164 pages
Book Rating : 4.7/5 (898 download)

DOWNLOAD NOW!


Book Synopsis Glia in Health and Disease by : Tania Spohr

Download or read book Glia in Health and Disease written by Tania Spohr and published by BoD – Books on Demand. This book was released on 2020-05-20 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book will highlight the role played by glial cells in the central and peripheral nervous systems in both healthy and unhealthy individuals. Among all processes involved, we will discuss the importance of the enteric nervous system in the control of gut homeostasis, in the interaction with the immune system, and its participation in pathological conditions such as metabolic syndrome. We will also look at the relevance of astrocytes during synaptic transmission and the regulation of plasticity by releasing gliotransmitters. Ultimately, we will highlight the influence of astrocytes during the development of a number of neurodegenerative diseases, such as multiple sclerosis and Alzheimer’s disease, focusing on how the serum levels of the astrocytic protein S100B can be used as a biomarker for clinical decisions.

Glial Neurobiology

Download Glial Neurobiology PDF Online Free

Author :
Publisher : John Wiley & Sons
ISBN 13 : 9780470513071
Total Pages : 230 pages
Book Rating : 4.5/5 (13 download)

DOWNLOAD NOW!


Book Synopsis Glial Neurobiology by : Alexei Verkhratsky

Download or read book Glial Neurobiology written by Alexei Verkhratsky and published by John Wiley & Sons. This book was released on 2007-08-20 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This volume is a very valuable and much needed contribution." –Quarterly Review of Biology AT LAST - A comprehensive, accessible textbook on glial neurobiology! Glial cells are the most numerous cells in the human brain but for many years have attracted little scientific attention. Neurophysiologists concentrated their research efforts instead, on neurones and neuronal networks because it was thought that they were the key elements responsible for higher brain function. Recent advances, however, indicate this isn’t exactly the case. Not only are astroglial cells the stem elements from which neurones are born, but they also control the development, functional activity and death of neuronal circuits. These ground-breaking developments have revolutionized our understanding of the human brain and the complex interrelationship of glial and neuronal networks in health and disease. Features of this book: an accessible introduction to glial neurobiology including an overview of glial cell function and its active role in neural processes, brain function and nervous system pathology an exploration of all the major types of glial cells including: the astrocytes, oligodendrocytes and microglia of the ACNS and Schwann cells of the peripheral nervous system; the book also presents a broad overview of glial receptors and ion channels an investigation into the role of glial cells in various types of brain diseases including stroke, neurodegenerative diseases such as Alzheimer's, Parkinson's and Alexander's disease, brain oedema, multiple sclerosis and many more a wealth of illustrations, including unique images from the authors' own libraries of images, describing the main features of glial cells Written by two leading experts in the field, Glial Neurobiology provides a concise, authoritative introduction to glial physiology and pathology for undergraduate/postgraduate neuroscience, biomedical, medical, pharmacy, pharmacology, and neurology, neurosurgery and physiology students. It is also an invaluable resource for researchers in neuroscience, physiology, pharmacology and pharmaceutics.

Enteric Glia

Download Enteric Glia PDF Online Free

Author :
Publisher : Biota Publishing
ISBN 13 : 1615046615
Total Pages : 72 pages
Book Rating : 4.6/5 (15 download)

DOWNLOAD NOW!


Book Synopsis Enteric Glia by : Brian D. Gulbransen

Download or read book Enteric Glia written by Brian D. Gulbransen and published by Biota Publishing. This book was released on 2014-07-01 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The enteric nervous system (ENS) is a complex neural network embedded in the gut wall that orchestrates the reflex behaviors of the intestine. The ENS is often referred to as the “little brain” in the gut because the ENS is more similar in size, complexity and autonomy to the central nervous system (CNS) than other components of the autonomic nervous system. Like the brain, the ENS is composed of neurons that are surrounded by glial cells. Enteric glia are a unique type of peripheral glia that are similar to astrocytes of the CNS. Yet enteric glial cells also differ from astrocytes in many important ways. The roles of enteric glial cell populations in the gut are beginning to come to light and recent evidence implicates enteric glia in almost every aspect of gastrointestinal physiology and pathophysiology. However, elucidating the exact mechanisms by which enteric glia influence gastrointestinal physiology and identifying how those roles are altered during gastrointestinal pathophysiology remain areas of intense research. The purpose of this e-book is to provide an introduction to enteric glial cells and to act as a resource for ongoing studies on this fascinating population of glia. Table of Contents: Introduction / A Historical Perspective on Enteric Glia / Enteric Glia: The Astroglia of the Gut / Molecular Composition of Enteric Glia / Development of Enteric Glia / Functional Roles of Enteric Glia / Enteric Glia and Disease Processes in the Gut / Concluding Remarks / References / Author Biography

Physiology and Function of Glial Cells in Health and Disease

Download Physiology and Function of Glial Cells in Health and Disease PDF Online Free

Author :
Publisher : IGI Global
ISBN 13 : 1668496763
Total Pages : 613 pages
Book Rating : 4.6/5 (684 download)

DOWNLOAD NOW!


Book Synopsis Physiology and Function of Glial Cells in Health and Disease by : El-Mansoury, Bilal

Download or read book Physiology and Function of Glial Cells in Health and Disease written by El-Mansoury, Bilal and published by IGI Global. This book was released on 2023-12-18 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glial cells, including microglia, astrocytes, oligodendrocytes, and their progenitors NG2-glia, serve as key players in maintaining structural integrity and complex brain homeostasis. They actively participate in neurotransmission, energy metabolism, synaptic plasticity, neurogenesis, ion balance, immune defense, and the clearance of neuronal debris. However, the physiological functions of glial cells are often compromised in aging, neurodegenerative diseases such as Alzheimer's, Parkinson's, ALS, and multiple sclerosis, as well as in gliomas, brain tumors demanding specialized understanding for effective therapeutic interventions. Physiology and Function of Glial Cells in Health and Disease provides a comprehensive exploration of the vital role played by glial cells in maintaining neural homeostasis within the central nervous system (CNS). This book delves into the intricate interaction between glial cells and neurons, shedding light on their essential contributions to neural function and overall brain health. The book also highlights emerging research on astrocyte reprogramming for the management of neurodegenerative diseases, offering a glimpse into potential future therapies. This book is an essential resource for researchers, clinicians, and students in the field of neuroscience. Its academic tone, coupled with in-depth discussions and cutting-edge insights, makes it a valuable reference for anyone seeking a comprehensive understanding of the role of glial cells in both health and disease.

Dual Role of Microglia in Health and Disease: Pushing the Balance Towards Repair

Download Dual Role of Microglia in Health and Disease: Pushing the Balance Towards Repair PDF Online Free

Author :
Publisher : Frontiers Media SA
ISBN 13 : 2889661067
Total Pages : 176 pages
Book Rating : 4.8/5 (896 download)

DOWNLOAD NOW!


Book Synopsis Dual Role of Microglia in Health and Disease: Pushing the Balance Towards Repair by : Raquel Ferreira

Download or read book Dual Role of Microglia in Health and Disease: Pushing the Balance Towards Repair written by Raquel Ferreira and published by Frontiers Media SA. This book was released on 2020-10-27 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Interaction Between Neurons and Glia in Aging and Disease

Download Interaction Between Neurons and Glia in Aging and Disease PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 0387708308
Total Pages : 524 pages
Book Rating : 4.3/5 (877 download)

DOWNLOAD NOW!


Book Synopsis Interaction Between Neurons and Glia in Aging and Disease by : Ana Cristina Rego

Download or read book Interaction Between Neurons and Glia in Aging and Disease written by Ana Cristina Rego and published by Springer Science & Business Media. This book was released on 2007-08-09 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: A superb source of reference reviews as well as a concise overview of the functional cross-talk between neurons and glial cells, this book also focuses on microglia and inflammation in the aging brain and in neurological disorders. The scientific spectrum covered by this book is of key interest, and is recognized by the scientific community as a major competitive area with critical implications for human health.

Glial Cell Development

Download Glial Cell Development PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 504 pages
Book Rating : 4.3/5 (91 download)

DOWNLOAD NOW!


Book Synopsis Glial Cell Development by : Kristjan R. Jessen

Download or read book Glial Cell Development written by Kristjan R. Jessen and published by . This book was released on 2001 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of cells in the nervous system are glial cells. During de velopment, these cells provide growth factors that stimulate the proli feration, migration and survival of neurones and their precursors, and promote and guide axonal growth. In the mature nervous system, glial cells provide insulating myelin sheath around axons and provide metabo lic and structural support for neurones. Glial cells also have a major influence on the local response to injury of central nerve tracts and the peripheral nervous system, either promoting, or inhibiting, axona l regrowth and recovery of lost function. This book provides a compreh ensive, state-of-the-art overview of research into the development, fu nction and malfunction of glial cells. It offers a compelling insight into how basic research throws light onto diseases and disorders and p oints the way towards treatments. Teams of internationally renowned ex perts, all active in research, have contributed chapters.

The Other Brain

Download The Other Brain PDF Online Free

Author :
Publisher : Simon and Schuster
ISBN 13 : 1439160430
Total Pages : 631 pages
Book Rating : 4.4/5 (391 download)

DOWNLOAD NOW!


Book Synopsis The Other Brain by : R. Douglas Fields

Download or read book The Other Brain written by R. Douglas Fields and published by Simon and Schuster. This book was released on 2009-12-29 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite everything that has been written about the brain, a potentially critical part of this vital organ has been overlooked—until now. The Other Brain examines the growing importance of glia, which make up approximately 85 percent of the cells in the brain, and the role they play in how the brain functions, malfunctions, and heals itself. Long neglected as little more than cerebral packing material, glia (meaning “glue”) are now known to regulate the flow of information between neurons and to repair the brain and spinal cord after injury and stroke. But scientists are also discovering that diseased and damaged glia play a significant role in psychiatric illnesses such as schizophrenia and depression, and in neurodegenerative diseases such as Parkinson’s and Alzheimer’s. Diseased glia cause brain cancer and multiple sclerosis and are linked to infectious diseases such as HIV and prion disease (mad cow disease, for example) and to chronic pain. The more we learn about these cells that make up the “other” brain, the more important they seem to be. Written by a neuroscientist who is a leader in glial research, The Other Brain gives readers a much more complete understanding of how the brain works and an intriguing look at potentially revolutionary developments in brain science and medicine.

Microglia in Health and Disease: A Unique Immune Cell Population

Download Microglia in Health and Disease: A Unique Immune Cell Population PDF Online Free

Author :
Publisher : Frontiers Media SA
ISBN 13 : 2889456013
Total Pages : 108 pages
Book Rating : 4.8/5 (894 download)

DOWNLOAD NOW!


Book Synopsis Microglia in Health and Disease: A Unique Immune Cell Population by : Alessandro Michelucci

Download or read book Microglia in Health and Disease: A Unique Immune Cell Population written by Alessandro Michelucci and published by Frontiers Media SA. This book was released on 2018-10-05 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microglia are essential for the development and function of the adult brain. Their ontogeny, together with the absence of turnover from the periphery and the singular environment of the central nervous system (CNS), make microglia a unique cell population compared to other tissue-macrophages. The unique properties and functions of microglial cells, such as their role in synaptic pruning or the exceptional capacity to scan the brain parenchyma and rapidly react to its perturbations, have emerged in recent years. In the coming years, understanding how microglia acquire and maintain their unique profiles in order to fulfil distinct tasks in the healthy CNS and how these are altered in disease, will be essential to develop strategies to diagnose or treat CNS disorders with an immunological component. This Research Topic covers several aspects of microglial biology, ranging from their origin and the functional role of microglia during development and lifespan, their molecular properties compared with other brain and peripheral immune cells to microglial phenotypes and functional states in neurodegenerative diseases and brain tumours. In conclusion, the present Research Topic provides a comprehensive overview of our current understanding of several cellular and molecular mechanisms that make microglia a unique immune cell population within the healthy CNS as well as under inflammatory, neurodegenerative and tumorigenic processes.

Glia

Download Glia PDF Online Free

Author :
Publisher : Cold Spring Harbor Perspective
ISBN 13 : 9781621820277
Total Pages : 0 pages
Book Rating : 4.8/5 (22 download)

DOWNLOAD NOW!


Book Synopsis Glia by : Ben Barres

Download or read book Glia written by Ben Barres and published by Cold Spring Harbor Perspective. This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of cells in the nervous system are glia. Long thought of as passive bystanders, glial cells are increasingly being appreciated for their active roles in nourishing, supporting, and protecting the neuronal cells that relay electrical signals through the nervous system. Written and edited by experts in the field, this collection from Cold Spring Harbor Perspectives in Biology examines the development of the major classes of glial cells-astrocytes, oligodendrocytes, Schwann cells, and microglia-and their roles in normal physiology and disease. The contributors describe how glia help establish and refine synaptic connections, maintain the metabolic and ionic milieu of nerve cells, myelinate axons, modulate nerve signal propagation, and contribute to the blood-brain barrier. The biological characteristics of glial cells in vertebrate and invertebrate model systems, including those of Drosophila, Caenorhabditis elegans, and zebrafish, are also covered. The authors also discuss the roles of glia in repair and regeneration, as well as in cancer and neurodegenerative diseases (e.g., Alzheimer's). This volume is therefore a valuable reference for all neurobiologists and biomedical scientists wishing to understand these diverse and dynamic cells.

The Neuronal Environment

Download The Neuronal Environment PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1592591086
Total Pages : 429 pages
Book Rating : 4.5/5 (925 download)

DOWNLOAD NOW!


Book Synopsis The Neuronal Environment by : Wolfgang Walz

Download or read book The Neuronal Environment written by Wolfgang Walz and published by Springer Science & Business Media. This book was released on 2001-12-26 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leading neuroscience researchers offer a fresh perspective on neuronal function by examining all its many components-including their pertubation during major disease states-and relate each element to neuronal demands. Topics range from the dependency of neurons on metabolic supply, as well as on both ion and transmitter homeostasis, to their close interaction with the myelin sheath. Also addressed are the astrocytic signaling system that controls synaptic transmission, the extracellular matrix and space as communication systems, the role of blood flow regulation in neuronal demand and in blood-brain barrier function, and inflammation and the neuroimmune system. Insightful and integrative, The Neuronal Environment: Brain Homeostasis in Health and Disease demonstrates a clear new understanding that neurons do not work in isolation, that they need constant interactions with other brain components to process information, and that they are not the only information processing system in the brain.

Glial Neurobiology

Download Glial Neurobiology PDF Online Free

Author :
Publisher : Wiley
ISBN 13 : 9780470015643
Total Pages : 230 pages
Book Rating : 4.0/5 (156 download)

DOWNLOAD NOW!


Book Synopsis Glial Neurobiology by : Alexei Verkhratsky

Download or read book Glial Neurobiology written by Alexei Verkhratsky and published by Wiley. This book was released on 2007-09-04 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This volume is a very valuable and much needed contribution." –Quarterly Review of Biology AT LAST - A comprehensive, accessible textbook on glial neurobiology! Glial cells are the most numerous cells in the human brain but for many years have attracted little scientific attention. Neurophysiologists concentrated their research efforts instead, on neurones and neuronal networks because it was thought that they were the key elements responsible for higher brain function. Recent advances, however, indicate this isn’t exactly the case. Not only are astroglial cells the stem elements from which neurones are born, but they also control the development, functional activity and death of neuronal circuits. These ground-breaking developments have revolutionized our understanding of the human brain and the complex interrelationship of glial and neuronal networks in health and disease. Features of this book: an accessible introduction to glial neurobiology including an overview of glial cell function and its active role in neural processes, brain function and nervous system pathology an exploration of all the major types of glial cells including: the astrocytes, oligodendrocytes and microglia of the ACNS and Schwann cells of the peripheral nervous system; the book also presents a broad overview of glial receptors and ion channels an investigation into the role of glial cells in various types of brain diseases including stroke, neurodegenerative diseases such as Alzheimer's, Parkinson's and Alexander's disease, brain oedema, multiple sclerosis and many more a wealth of illustrations, including unique images from the authors' own libraries of images, describing the main features of glial cells Written by two leading experts in the field, Glial Neurobiology provides a concise, authoritative introduction to glial physiology and pathology for undergraduate/postgraduate neuroscience, biomedical, medical, pharmacy, pharmacology, and neurology, neurosurgery and physiology students. It is also an invaluable resource for researchers in neuroscience, physiology, pharmacology and pharmaceutics.

Nervous Tissue Cells in Health and Disease

Download Nervous Tissue Cells in Health and Disease PDF Online Free

Author :
Publisher : Murphy & Moore Publishing
ISBN 13 : 9781639877928
Total Pages : 0 pages
Book Rating : 4.8/5 (779 download)

DOWNLOAD NOW!


Book Synopsis Nervous Tissue Cells in Health and Disease by : Emma Hixon

Download or read book Nervous Tissue Cells in Health and Disease written by Emma Hixon and published by Murphy & Moore Publishing. This book was released on 2023-09-26 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nervous tissue is referred to as the primary tissue component of the nervous system. It can be found in the nerves, brain and spinal cord. Glial cells and neurons are the two types of cells that make up nervous tissue. Neurons are responsible for the communication and computation provided by the nervous system. Glial cells play a supporting role for nervous tissues and are considerably smaller than neurons. They enhance signal conduction within neurons and defend neurons from pathogens. Many body activities are controlled and coordinated by the nervous tissue. It develops environmental awareness, promotes muscle contraction and plays an important role in thinking, emotions and memory. The function of the nervous tissue is to create the communication network of the nervous system by conducting electric signals through the tissue. This book provides comprehensive insights on the role of nervous tissue cells in health and disease. It presents researches and studies performed by experts across the globe. The readers would gain knowledge that would broaden their perspective in this area of study.