Download or read book Intrinsic Clocks written by Timo Partonen and published by Frontiers Media SA. This book was released on 2018-03-19 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Intrinsic Clocks" presents an array of current research activities on intrinsic clocks and their contributions to biology and physiology. It elucidates the current models for the intrinsic clocks, their molecular components and key mechanisms as well as the key brain regions and animal models for their behavioral analysis. It provides a timely view on how these clocks guide behavior, and how their disruption may cause depressive-like behavior and impairment in cognitive functions. Thereby, any specific method by which the mood-related functions of the intrinsic clocks might be influenced bears therapeutic potential and has clinical interest. The importance of some of these mechanisms was highlighted by the 2017 award of the Nobel Prize in Physiology or Medicine to Jeffrey C. Hall, Michael Rosbash, and Michael W. Young for their discoveries of the genetic control of the daily biological rhythm. The key to the explanation was the discovery of transcription-translation feedback loops of the so-called “clock genes.”
Download or read book Timing of Biological Clocks written by Arthur T. Winfree and published by Macmillan + ORM. This book was released on 1986-11-15 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A clock," writes Arthur T. Winfree, "is not much good if you can't pull out its stem and set it." Similarly, the most critical property of biological clocks--which rhythmically organize the processes of life--is their ability to reset on cue. This ability allows enables biological clocks to regain synchrony with a changing environment (as when we travel across time zones) or to maintain the alignment between certain physiological rhythms and the natural solar day. In The Timing of Biological Clocks, Winfree explores circadian rhythms. In reporting experiments on animals, plants, and single cells, he not only illustrates the principles that guide the resetting of biological clocks but reveals that each of these clocks has a vulnerable phase, a moment in each "turn of the dial" when a cueing stimulus of a particular intensity results in an abnormal, unpredictable resetting--perhaps even annihilating the clock's rhythm entirely. A singular feature of the author's exploration of these phenomena is his use of a range of colors to represent the passage of cyclic time. By this device, Winfree not only removes the purely arbitrary discontinuity of a conventional clock dial but makes reasoning about the real discontinuities of biological clocks transparently clear.
Download or read book Circadian Clocks written by Tsuyoshi Hirota and published by Springer Nature. This book was released on 2022-09-15 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides backgrounds, methods, and troubleshooting for the analysis of circadian rhythms at the molecular, cellular, and organismal levels in vertebrates and invertebrates, and also covers light input, sleep, circalunar rhythms, and seasonal rhythms. The chapters in this book discuss behavioral and biological testing, histochemistry, single-cell imaging, electrophysiology, photochemistry, genetics, genomics, transcriptomics, proteomics, metabolomics, systems biology, chemical biology, and mathematical modeling. In the Neuromethods series style, chapters include experimental detail and key advice from the specialists needed to successfully carry out these methods in your laboratory. Cutting-edge and practical, Circadian Clocks is a valuable resource for all researchers seeking to learn about established and novel methods in chronobiology, and the molecular mechanisms of the rhythmic control of physiology and behavior.
Download or read book Circadian Clocks and Their Adjustment written by Derek J. Chadwick and published by John Wiley & Sons. This book was released on 2008-04-30 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prestigious contributors describe the genetic, molecular, anatomical and neurochemical mechanisms and pathways that operate to regulate and control circadian rhythmicity and functioning in organisms ranging from unicellular algae to human beings. Also considers the implications of the basic and clinical research for humans.
Download or read book Intrinsic Clocks written by and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Intrinsic Clocks" presents an array of current research activities on intrinsic clocks and their contributions to biology and physiology. It elucidates the current models for the intrinsic clocks, their molecular components and key mechanisms as well as the key brain regions and animal models for their behavioral analysis. It provides a timely view on how these clocks guide behavior, and how their disruption may cause depressive-like behavior and impairment in cognitive functions. Thereby, any specific method by which the mood-related functions of the intrinsic clocks might be influenced bears therapeutic potential and has clinical interest. The importance of some of these mechanisms was highlighted by the 2017 award of the Nobel Prize in Physiology or Medicine to Jeffrey C. Hall, Michael Rosbash, and Michael W. Young for their discoveries of the genetic control of the daily biological rhythm. The key to the explanation was the discovery of transcription-translation feedback loops of the so-called "clock genes."
Download or read book The Living Clock written by John D. Palmer and published by Oxford University Press. This book was released on 2002-03-14 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: From one-celled paramecium to giant blue whales, we all have internal clocks that regulate the rhythms we live by. In The Living Clock, John Palmer, one of the world's leading authorities on these rhythms, takes us on a tour of this broad and multifaceted subject, examining everything from glowing fruit flies to the best cures for jet lag. Palmer has a wonderful sense of humor and an eye for the startling fact. We learn that fiddler crabs--in a lab where there are no time nor tide cues--remain active when low tide would occur and motionless during high tide, the same pattern they follow in their natural habitat. (In fact, you can remove a crab's leg and the leg will keep a tidal rhythm as long as it's kept alive.) Moreover, humans are subject to more than one hundred biological rhythms. Mental acuity peaks in the afternoon, for instance, and our blood pressure peaks at seven in the morning (when most heart attacks occur). The time of day you take medication can affect how well it works. And Palmer shows that when our clocks are thrown off kilter, trouble follows, especially for rotating shift workers--the Bhopal spill, the Chernobyl reactor explosion, and the Three Mile Island accident all happened when new crews began early-hour shifts. No one has discovered exactly how our internal clocks work--Palmer says a Nobel Prize awaits that lucky scientist--but they are no less fascinating for their inexplicable nature. Frequently amusing and always eye-opening, The Living Clock is a treat for everyone curious about the nature of life as well as anyone planning a long jet flight.
Download or read book Of Time Tides and Inner Clocks written by Henry Still and published by . This book was released on 1972 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Circadian Clock Functions volume II written by Daisuke Ono and published by Frontiers Media SA. This book was released on 2024-07-31 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The temporal order of physiological functions such as sleep/wakefulness is regulated by the circadian clock. This intrinsic clock starts ticking in the embryo and matures during development, with attenuation of the clock function in the elderly, illustrated by attenuation of synchrony, entrainment, and outputs of cellular circadian rhythms in the SCN. This age-related diminution can contribute to the emergence of diseases, such as sleep disorders, infertility, diabetes, mental disorders etc. Over the course of our lives, a variety of internal and external factors are under the influence of the circadian clock. This inherent developmental plasticity of the circadian system is critical for the establishment of normal bodily functions to adapt to the changing environment on earth. In mammals, the central circadian clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Circadian rhythms in the SCN are observed during the embryonic period, and input and output pathways from the SCN are formed after birth. During postnatal development, functions of neurotransmitters in the SCN are changed, which have an influence on special temporal patterns of circadian rhythms in the SCN and outputs signals to the outside of the SCN. During postnatal development properties of circadian rhythms in the SCN and its inputs and outputs can be modulated by environmental light conditions. Recent optical manipulation and imaging techniques have revealed that cell type specific functions for circadian rhythms. However, it remains unclear which cell types or networks in the brain are modulated during postnatal development, and how these cells regulate circadian rhythms depending on postnatal period.
Download or read book From Sundials to Atomic Clocks written by James Jespersen and published by Courier Corporation. This book was released on 1999-01-01 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clear and accessible introduction to the concept of time examines measurement, historic timekeeping methods, uses of time information, role of time in science and technology, and much more. Over 300 illustrations.
Download or read book Neuronal Input Pathways to the Brain s Biological Clock and their Functional Significance written by Jens Hannibal and published by Springer Science & Business Media. This book was released on 2006-06-07 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rhythmic changes in physiology and behaviour within a 24 h period occur in living organisms on earth to meet the challenges associated with the daily changes in the external environment. The circadian pacemaker responsible for the temporal internal organisation and the generation of endogenous rhythms of approximately 24 h is located in the hypothalamic suprachiasmatic nucleus (SCN) in mammals. The endogenous period generated by the pacemaker is close to, but generally not equal to 24 h and the biological clock therefore needs to be daily adjusted (entrained) by external cues. The daily alteration of light and darkness due to the rotation of our planet on its own axis in relation to the sun is the most prominent "zeitgeber" which adjusts the phase of the circadian rhythms to the astronomical day length, a process known as photoentrainment. In mammals, light is perceived only through photoreceptors located in the retina. Light information is mediated to the SCN via the retinohypothalamic tract (RHT) by activation of the classical photoreceptor system of rods and cones and a more recently identified system of intrinsic photosensitive retinal ganglion cells (ipRGCs) using melanopsin as a photopigment.
Download or read book Inner Time written by Carol Orlock and published by Citadel Press. This book was released on 1993 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crops. Like the animals and plants around us, we are tuned to the cycles of our planet. Time cycles, encoded into our cells, tell us when to sleep and wake, work and play. When we ignore them, we put both our health and our happiness at risk. The development of chronobiology represents a new era in our understanding of the universe. Like the discovery of the microscope, chronobiology is revolutionizing how we view ourselves and our world on every level. Inner Time.
Download or read book Suprachiasmatic Nucleus written by David C. Klein and published by Oxford University Press, USA. This book was released on 1991 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on a conference funded by the National Institutes of Health, this timely book is the most up-to-date and definitive reference on the suprachiasmatic nucleus (SCN), the part of the brain that controls circadian rhythms in mammals. These biological rhythms range from daily fluctuations in metabolism to seasonal and annual cycles. This book comprehensive and incisive review of the SCN covers anatomy and physiology, intrinsic SCN rhythms, circadian rhythms, neuropharmacology, transplants, and development.
Download or read book Regulation and Synchronization of the Master Circadian Clock by Purinergic Signaling from Suprachiasmatic Nucleus Astrocytes written by Alisa Diane Womac and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular, cellular, and physiological processes within an organism are set to occur at specific times throughout the day. The timing of these processes is under control of a biological clock. Nearly all organisms on Earth have biological clocks, ranging from unicellular bacteria and fungi to multicellular plants, insects, reptiles, fish, birds, and mammals. The biological clock is an endogenous time-keeping mechanism that generates the onset of many processes and coordinates the phases of processes over 24 hours. While the biological clock allows these organisms to maintain roughly 24-hour, or circadian, timing in daily processes, many organisms have the ability to set their clocks, or entrain them, to changes in light. In mammals, the suprachiasmatic nucleus (SCN) is the master biological clock that entrains daily physiological and behavioral rhythms to the appropriate times of day and night. The SCN is located in the hypothalamus and contains thousands of neurons and glia that function in coordinating system-level physiological rhythms that are entrained to environmental light cues. Many of these neurons and glia are individual circadian oscillators, and the cellular mechanisms that couple them into ensemble oscillations are emerging. Adenosine triphosphate (ATP) is a transmitter involved in local communication among astrocytes and between astrocytes and neurons. ATP released from astrocytes may play a role in SCN cellular communication and synchrony. Extracellular ATP accumulated rhythmically in the rat SCN in vivo, and ATP released from rat SCN astrocytes in vitro was rhythmic, with a periodicity near 24 hours. ATP released from mouse SCN astrocytes was circadian, and disruption of the molecular clock abolished rhythmic extracellular ATP accumulation. SCN astrocyte cultures with disrupted molecular clocks also had marked reductions in total ATP accumulation compared to SCN astrocyte cultures with functional biological clocks. Furthermore, ATP-induced calcium transients were rhythmic, and this rhythmic purinergic sensitivity was abolished in clock mutant astrocytes. Pharmacological blockade of purinergic signaling, with antagonists of both the P2X7 and P2Y1 receptors, led to a gradual reduction in the amplitude of coordinated ATP accumulation over three days. These purinergic receptor antagonists, as expected, led to a reduction in calcium responses of SCN astrocytes to ATP and led to a dampening of clock gene expression rhythms as determined by PER2::LUC bioluminescence reporting in SCN astrocytes. These data demonstrate that astrocytes of the mammalian SCN rhythmically release ATP and are rhythmically sensitive to ATP in a manner dependent on their intrinsic molecular clock. Ensemble rhythmicity of SCN astrocytes is, in turn, dependent on that rhythmic purinergic signaling via both P2X and P2Y classes of ATP receptors. These results are indicative of a functional role for ATP accumulation within the SCN, with astrocytes releasing ATP every 24 hours for continual signaling onto astrocytes and neurons to maintain daily coordinated synchrony of the clocks in these cells.
Download or read book Of Clocks and Time written by Lutz Hüwel and published by Morgan & Claypool Publishers. This book was released on 2018-05-03 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of Clocks and Time takes readers on a five-stop journey through the physics and technology (and occasional bits of applications and history) of timekeeping. On the way, conceptual vistas and qualitative images abound, but since mathematics is spoken everywhere the book visits equations, quantitative relations, and rigorous definitions are offered as well. The expedition begins with a discussion of the rhythms produced by the daily and annual motion of sun, moon, planets, and stars. Centuries worth of observation and thinking culminate in Newton's penetrating theoretical insights since his notion of space and time are still influential today. During the following two legs of the trip, tools are being examined that allow us to measure hours and minutes and then, with ever growing precision, the tiniest fractions of a second. When the pace of travel approaches the ultimate speed limit, the speed of light, time and space exhibit strange and counter-intuitive traits. On this fourth stage of the journey, Einstein is the local tour guide whose special and general theories of relativity explain the behavior of clocks under these circumstances. Finally, the last part of the voyage reverses direction, moving ever deeper into the past to explore how we can tell the age of "things" - including that of the universe itself.
Download or read book The Living Clocks written by Ritchie R. Ward and published by . This book was released on 1972 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Accurate Clock Pendulums written by Robert J. Matthys and published by Oxford University Press. This book was released on 2004-06-03 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Shortt clock, made in the 1920s, is the most famous accurate clock pendulum ever known, having an accuracy of one second per year when kept at nearly constant temperature. Almost all of a pendulum clock's accuracy resides in its pendulum. If the pendulum is accurate, the clock will be accurate. In this book, the author describes many scientific aspects of pendulum design and operation in simple terms with experimental data, and little mathematics. It has been written, looking atall the different parts and aspects of the pendulum in great detail, chapter by chapter, reflecting the degree of attention necessary for making a pendulum run accurately. The topics covered include the dimensional stability of different pendulum materials, good and poor suspension spring designs,the design of mechanical joints and clamps, effect of quartz on accuracy, temperature compensation, air drag of different bob shapes and making a sinusoidal electromagnetic drive. One whole chapter is devoted to simple ways of improving the accuracy of ordinary low-cost pendulum clocks, which have a different construction compared to the more expensive designs of substantially well-made ones. This book will prove invaluable to anyone who wants to know how to make a more accurate pendulum orpendulum clock.
Download or read book The Measurement of Time written by Claude Audoin and published by Cambridge University Press. This book was released on 2001-09-06 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unique insight into the measurement of time and its applications, at an introductory level.
