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Artículos de revistas sobre el tema "Desynchronization under constant light"

Autor: Grafiati

Publicado: 28 de junio de 2021

Última modificación: 12 de febrero de 2022

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1

Rumanova, Valentina S., Monika Okuliarova y Michal Zeman. "Differential Effects of Constant Light and Dim Light at Night on the Circadian Control of Metabolism and Behavior". International Journal of Molecular Sciences 21, n.º 15 (31 de julio de 2020): 5478. http://dx.doi.org/10.3390/ijms21155478.

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The disruption of circadian rhythms by environmental conditions can induce alterations in body homeostasis, from behavior to metabolism. The light:dark cycle is the most reliable environmental agent, which entrains circadian rhythms, although its credibility has decreased because of the extensive use of artificial light at night. Light pollution can compromise performance and health, but underlying mechanisms are not fully understood. The present review assesses the consequences induced by constant light (LL) in comparison with dim light at night (dLAN) on the circadian control of metabolism and behavior in rodents, since such an approach can identify the key mechanisms of chronodisruption. Data suggest that the effects of LL are more pronounced compared to dLAN and are directly related to the light level and duration of exposure. Dim LAN reduces nocturnal melatonin levels, similarly to LL, but the consequences on the rhythms of corticosterone and behavioral traits are not uniform and an improved quantification of the disrupted rhythms is needed. Metabolism is under strong circadian control and its disruption can lead to various pathologies. Moreover, metabolism is not only an output, but some metabolites and peripheral signal molecules can feedback on the circadian clockwork and either stabilize or amplify its desynchronization.

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2

Poulis, J. A., F. Roelfsema y D. van der Heide. "Circadian urinary excretion rhythms in adrenalectomized rats". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 251, n.º 3 (1 de septiembre de 1986): R441—R449. http://dx.doi.org/10.1152/ajpregu.1986.251.3.r441.

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The impact of the adrenal system on urinary rhythms was investigated in adrenalectomized (ADX) rats under various experimental conditions. During a 12:12 light-dark cycle the acrophases were shifted in ADX rats with respect to control rats. Under constant light conditions ADX rats displayed free-running rhythms, similar to those of control rats. The periods were stable in blind rats but not in rats maintained on a constant light cycle. The abrupt change in period, which occurred after approximately 8 days, suggests a stage of internal desynchronization. A 6-h delay in the administration of corticosterone to ADX rats caused a delay shift of the acrophases. A single intraperitoneal injection of corticosterone in blind free-running ADX rats caused delay or advance shifts so that we could construct phase-response curves for the various excretory rhythms. These observations indicate that the adrenals are not essential for the establishment of the urinary rhythms; however, corticosterone influences the phase setting of these rhythms. The site of action is probably the X pacemaker (controlling the body temperature rhythm), although we cannot totally exclude an additional effect on secondary (renal) oscillators.

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3

Guerriero, Maria Luisa, Alexandra Pokhilko, Aurora Piñas Fernández, Karen J. Halliday, Andrew J. Millar y Jane Hillston. "Stochastic properties of the plant circadian clock". Journal of The Royal Society Interface 9, n.º 69 (31 de agosto de 2011): 744–56. http://dx.doi.org/10.1098/rsif.2011.0378.

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Circadian clocks are gene regulatory networks whose role is to help the organisms to cope with variations in environmental conditions such as the day/night cycle. In this work, we explored the effects of molecular noise in single cells on the behaviour of the circadian clock in the plant model species Arabidopsis thaliana . The computational modelling language Bio-PEPA enabled us to give a stochastic interpretation of an existing deterministic model of the clock, and to easily compare the results obtained via stochastic simulation and via numerical solution of the deterministic model. First, the introduction of stochasticity in the model allowed us to estimate the unknown size of the system. Moreover, stochasticity improved the description of the available experimental data in several light conditions: noise-induced fluctuations yield a faster entrainment of the plant clock under certain photoperiods and are able to explain the experimentally observed dampening of the oscillations in plants under constant light conditions. The model predicts that the desynchronization between noisy oscillations in single cells contributes to the observed damped oscillations at the level of the cell population. Analysis of the phase, period and amplitude distributions under various light conditions demonstrated robust entrainment of the plant clock to light/dark cycles which closely matched the available experimental data.

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4

Yamanaka, Yujiro. "Basic concepts and unique features of human circadian rhythms: implications for human health". Nutrition Reviews 78, Supplement_3 (26 de noviembre de 2020): 91–96. http://dx.doi.org/10.1093/nutrit/nuaa072.

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Abstract Most physiological functions and behaviors exhibit a robust approximately 24-hour rhythmicity (circadian rhythm) in the real world. These rhythms persist under constant conditions, but the period is slightly longer than 24 hours, suggesting that circadian rhythms are endogenously driven by an internal, self-sustained oscillator. In mammals, including humans, the central circadian pacemaker is located in the hypothalamic suprachiasmatic nucleus. The primary zeitgeber for this pacemaker is bright sunlight, but nonphotic time cues also affect circadian rhythms. The human circadian system uniquely exhibits spontaneous internal desynchronization between the sleep-wake cycle and core body temperature rhythm under constant conditions and partial entrainment of the sleep-wake cycle in response to nonphotic time cues. Experimental and clinical studies of human circadian rhythms must take into account these unique features. This review covers the basic concepts and unique features of the human circadian system, the mechanisms underlying phase adjustment of the circadian rhythms by light and nonphotic time cues (eg, physical exercise), and the effects of eating behavior (eg, chewing frequency) on the circadian rhythm of glucose metabolism.

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5

Madrid, J. A., F. J. Sánchez-Vázquez, P. Lax, P. Matas, E. M. Cuenca y S. Zamora. "Feeding behavior and entrainment limits in the circadian system of the rat". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 275, n.º 2 (1 de agosto de 1998): R372—R383. http://dx.doi.org/10.1152/ajpregu.1998.275.2.r372.

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The entrainment limits of the circadian rhythms of feeding activity were studied in Wistar rats exposed to gradually increasing and decreasing or to static light-dark cycles. In the former, the entrainment limits of feeding behavior were 22 h 10 min and 26 h 40 min. In the latter, the upper limit was higher, because rats under zeitgeber period ( t) length = 27 h ( t27) and t28 met the criteria of entrainment. The lower limit, on the other hand, was not modified because none of the t22 animals showed entrained rhythms and one-half of the t23 rats exhibited two components in their circadian feeding rhythms, one with a period of 23 h and the other free running. This 23-h component reflected not only the masking effect of light-dark cycles but also seemed a true light-entrained component. In well-synchronized animals, food intake seemed to depend more on the number of cycles that the animal experienced than on actual time lived; however, other feeding parameters, such as meal frequency and feeding duration, remained constant when expressed per 24 h, irrespective of the t cycle. These results concerning feeding duration, meal frequency, and food intake revealed that the homeostatic and circadian controls interacted to a degree that depended on the type of variable considered. In conclusion, the entrainment limits appeared much more imprecise than they were previously thought to be, because the circadian system can only be partially synchronized near its entrainment limits. The hypothesis that the rat’s circadian system is composed of multiple oscillators with different intrinsic frequencies and varying capacities for light synchronization would explain the partial desynchronization observed near the entrainment limits.

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6

RAMÍREZ ÁVILA, GONZALO M., JEAN-LUC GUISSET y JEAN-LOUIS DENEUBOURG. "INFLUENCE OF UNIFORM NOISE ON TWO LIGHT-CONTROLLED OSCILLATORS". International Journal of Bifurcation and Chaos 17, n.º 12 (diciembre de 2007): 4453–62. http://dx.doi.org/10.1142/s0218127407020117.

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We study the influence of uniform noise on a system of two light-controlled oscillators (LCOs) under three different configurations: uncoupled, master–slave and mutually coupled LCOs. We find that noise can induce desynchronization via a phase transition-like phenomenon depending on the noise intensity and the characteristics of the LCOs.

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7

Aryal, Uma K., Jana Stöckel, Eric A. Welsh, Marina A. Gritsenko, Carrie D. Nicora, David W. Koppenaal, Richard D. Smith, Himadri B. Pakrasi y Jon M. Jacobs. "Dynamic Proteome Analysis ofCyanothecesp. ATCC 51142 under Constant Light". Journal of Proteome Research 11, n.º 2 (diciembre de 2011): 609–19. http://dx.doi.org/10.1021/pr200959x.

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8

Liu, Ji, Klara Pendrak, Cheryl Capehart, Reiko Sugimoto, Gregor F. Schmid y Richard A. Stone. "Emmetropisation under continuous but non-constant light in chicks". Experimental Eye Research 79, n.º 5 (noviembre de 2004): 719–28. http://dx.doi.org/10.1016/j.exer.2004.08.007.

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9

Rosenwasser, Alan M., Walter D. McCulley, Matthew C. Hartmann, Michael C. Fixaris y John C. Crabbe. "Suppression of voluntary ethanol intake in mice under constant light and constant darkness". Alcohol 83 (marzo de 2020): 37–46. http://dx.doi.org/10.1016/j.alcohol.2019.05.009.

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10

Mizutani, Hiromi, Risa Tamagawa‐Mineoka, Risa Yasuike, Yoichi Minami, Kazuhiro Yagita y Norito Katoh. "Effects of constant light exposure on allergic and irritant contact dermatitis in mice reared under constant light conditions". Experimental Dermatology 30, n.º 5 (25 de febrero de 2021): 739–44. http://dx.doi.org/10.1111/exd.14308.

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11

Wang, Jianbin, Zhanhao Hu, Zhiming Zhong, Lei Wang, Jianhua Zou, Yueju Su, Dongyu Gao et al. "Stressing organic light-emitting diode under constant-brightness driving mode". Organic Electronics 21 (junio de 2015): 192–97. http://dx.doi.org/10.1016/j.orgel.2015.03.025.

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12

Túnez, Isaac, María del Carmen Muñoz, Montserrat Feijoo, Manuel E. Valdelvira, Juan Rafael Muñoz-Castañeda y Pedro Montilla. "Melatonin effect on renal oxidative stress under constant light exposure". Cell Biochemistry and Function 21, n.º 1 (7 de octubre de 2002): 35–40. http://dx.doi.org/10.1002/cbf.994.

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13

Túnez, I., M. C. Muñoz, M. Feijoo-López, E. Valdelvira, I. Bujalance-Arenas y P. Montilla. "Effect of melatonin on hyperlipidemic nephropathy under constant light exposure". Journal of Physiology and Biochemistry 58, n.º 2 (junio de 2002): 109–14. http://dx.doi.org/10.1007/bf03179846.

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14

Aguzzi, Jacopo, Nicole M. Bullock y Gianluca Tosini. "Spontaneous internal desynchronization of locomotor activity and body temperature rhythms from plasma melatonin rhythm in rats exposed to constant dim light". Journal of Circadian Rhythms 4 (4 de abril de 2006): 6. http://dx.doi.org/10.1186/1740-3391-4-6.

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15

Depres-Brummer, P., F. Levi, G. Metzger y Y. Touitou. "Light-induced suppression of the rat circadian system". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 268, n.º 5 (1 de mayo de 1995): R1111—R1116. http://dx.doi.org/10.1152/ajpregu.1995.268.5.r1111.

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In a constant environment, circadian rhythms persist with slightly altered period lengths. Results of studies with continuous light exposure are less clear, because of short exposure durations and single-variable monitoring. This study sought to characterize properties of the oscillator(s) controlling the rat's circadian system by monitoring both body temperature and locomotor activity. We observed that prolonged exposure of male Sprague-Dawley rats to continuous light (LL) systematically induced complete suppression of body temperature and locomotor activity circadian rhythms and their replacement by ultradian rhythms. This was preceded by a transient loss of coupling between both functions. Continuous darkness (DD) restored circadian synchronization of temperature and activity circadian rhythms within 1 wk. The absence of circadian rhythms in LL coincided with a mean sixfold decrease in plasma melatonin and a marked dampening but no abolition of its circadian rhythmicity. Restoration of temperature and activity circadian rhythms in DD was associated with normalization of melatonin rhythm. These results demonstrated a transient internal desynchronization of two simultaneously monitored functions in the rat and suggested the existence of two or more circadian oscillators. Such a hypothesis was further strengthened by the observation of a circadian rhythm in melatonin, despite complete suppression of body temperature and locomotor activity rhythms. This rat model should be useful for investigating the physiology of the circadian timing system as well as to identify agents and schedules having specific pharmacological actions on this system.

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16

Amano, Masafumi, Masayuki Iigo, Shoji Kitamura, Noriko Amiya y Kunio Yamamori. "Changes in melatonin binding sites under artificial light–dark, constant light and constant dark conditions in the masu salmon brain". Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 144, n.º 4 (agosto de 2006): 509–13. http://dx.doi.org/10.1016/j.cbpa.2006.04.018.

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17

Cambras, Trinitat, John R. Weller, Montserrat Anglès-Pujoràs, Michael L. Lee, Andrea Christopher, Antoni Díez-Noguera, James M. Krueger y Horacio O. de la Iglesia. "Circadian desynchronization of core body temperature and sleep stages in the rat". Proceedings of the National Academy of Sciences 104, n.º 18 (23 de abril de 2007): 7634–39. http://dx.doi.org/10.1073/pnas.0702424104.

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Proper functioning of the human circadian timing system is crucial to physical and mental health. Much of what we know about this system is based on experimental protocols that induce the desynchronization of behavioral and physiological rhythms within individual subjects, but the neural (or extraneural) substrates for such desynchronization are unknown. We have developed an animal model of human internal desynchrony in which rats are exposed to artificially short (22-h) light–dark cycles. Under these conditions, locomotor activity, sleep–wake, and slow-wave sleep (SWS) exhibit two rhythms within individual animals, one entrained to the 22-h light–dark cycle and the other free-running with a period >24 h (τ>24 h). Whereas core body temperature showed two rhythms as well, further analysis indicates this variable oscillates more according to the τ>24 h rhythm than to the 22-h rhythm, and that this oscillation is due to an activity-independent circadian regulation. Paradoxical sleep (PS), on the other hand, shows only one free-running rhythm. Our results show that, similarly to humans, (i) circadian rhythms can be internally dissociated in a controlled and predictable manner in the rat and (ii) the circadian rhythms of sleep–wake and SWS can be desynchronized from the rhythms of PS and core body temperature within individual animals. This model now allows for a deeper understanding of the human timekeeping mechanism, for testing potential therapies for circadian dysrhythmias, and for studying the biology of PS and SWS states in a neurologically intact model.

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18

Smrčinová, Miroslava, Preben Graae Sørensen, Július Krempasky y Peter Ballo. "Chaotic Oscillations in a Chloroplast System Under Constant Illumination". International Journal of Bifurcation and Chaos 08, n.º 12 (diciembre de 1998): 2467–70. http://dx.doi.org/10.1142/s0218127498001984.

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We show that nonlinear, aperiodic oscillatory behavior can be observed in a chloroplast system by measuring the absorption of light. This behavior depends on illumination of the system with light which is absorbed by chlorophyll. The oscillations can be stopped by addition of acetone indicating that chemical reactions are involved. These observations confirm the role of photosynthesis. The effect of stirring and the statistics of the oscillating part of the spectrum suggest that the buoyancy of oxygen bubbles formed during photosynthesis is an important art of the mechanism.

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19

Cruz, Adolfo, Francisco J. Padillo, Jose Granados, Isaac Túnez, M. Carmen Muñoz, Javier Briceño, Carlos Pera-Madrazo y Pedro Montilla. "Effect of melatonin on cholestatic oxidative stress under constant light exposure". Cell Biochemistry and Function 21, n.º 4 (30 de mayo de 2003): 377–80. http://dx.doi.org/10.1002/cbf.1046.

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20

Gervais, Frank. "Oxygen Productivity of Planktonic Algae under Fluctuating and Constant Light Conditions". International Review of Hydrobiology 96, n.º 5 (noviembre de 2011): 622–30. http://dx.doi.org/10.1002/iroh.201111277.

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21

TOIDA, Hiromi, Yoshitaka OMURA, Chieri KUBOTA y Toyoki KOZAI. "Growth and Development of Tomato Seedlings under Constant Light-dark Period with Random Light Periods". Environment Control in Biology 41, n.º 4 (2003): 369–75. http://dx.doi.org/10.2525/ecb1963.41.369.

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22

Moura, Clarissa de Almeida, Jéssica Polyana da Silva Lima, Vanessa Augusta Magalhães Silveira, Mário André Leocadio Miguel y Ana Carolina Luchiari. "Time place learning and activity profile under constant light and constant dark in zebrafish (Danio rerio)". Behavioural Processes 138 (mayo de 2017): 49–57. http://dx.doi.org/10.1016/j.beproc.2017.02.015.

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23

Proshold, F. I. "Sperm Transfer in Gypsy Moths: Effect of Constant or Cyclic Temperature and Constant Light or Darkness during the Pupal Stage". Journal of Entomological Science 32, n.º 3 (1 de julio de 1997): 321–31. http://dx.doi.org/10.18474/0749-8004-32.3.321.

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Sperm transfer and fertility of the gypsy moth, Lymantria dispar (L.), held as pupae under constant temperature and 24-h light, 24-h darkness, or a photoperiod of 16:8 (L:D) h were compared with males held in cyclic temperature and 24-h light, 24-h darkness, or a photoperiod of 16:8 (L:D) h. Constant temperature and constant light or darkness severely reduced its ability to transfer sperm. Males held under constant light were more severely affected than males held in darkness, but sperm transfer was not correlated with light intensity (between 80 and 3960 lux). Nearly all males held under constant light and most held under constant darkness were sterile or partially sterile. In either case, sterility was caused by poor sperm transfer. Females with a full complement of sperm were fertile regardless of holding condition of male pupae. The sterilizing effect of constant light or darkness was overridden by cyclic temperature of 28°C for 16 h and 22°C for 8 h. At a photoperiod of 16:8 h, pupae held in constant 28°C transferred less sperm than those held at 25°C. Pupae held at constant 30°C were sterile, but those held at 30°C for 16 h and 25°C for 8 h transferred similar quantities of sperm as males held at constant 28°C.

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24

Roach, Thomas. "LHCSR3-Type NPQ Prevents Photoinhibition and Slowed Growth under Fluctuating Light in Chlamydomonas reinhardtii". Plants 9, n.º 11 (18 de noviembre de 2020): 1604. http://dx.doi.org/10.3390/plants9111604.

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Natural light intensities can rise several orders of magnitude over subsecond time spans, posing a major challenge for photosynthesis. Fluctuating light tolerance in the green alga Chlamydomonas reinhardtii requires alternative electron pathways, but the role of nonphotochemical quenching (NPQ) is not known. Here, fluctuating light (10 min actinic light followed by 10 min darkness) led to significant increase in NPQ/qE-related proteins, LHCSR1 and LHCSR3, relative to constant light of the same subsaturating or saturating intensity. Elevated levels of LHCSR1/3 increased the ability of cells to safely dissipate excess light energy to heat (i.e., qE-type NPQ) during dark to light transition, as measured with chlorophyll fluorescence. The low qE phenotype of the npq4 mutant, which is unable to produce LHCSR3, was abolished under fluctuating light, showing that LHCSR1 alone enables very high levels of qE. Photosystem (PS) levels were also affected by light treatments; constant light led to lower PsbA levels and Fv/Fm values, while fluctuating light led to lower PsaA and maximum P700+ levels, indicating that constant and fluctuating light induced PSII and PSI photoinhibition, respectively. Under fluctuating light, npq4 suffered more PSI photoinhibition and significantly slower growth rates than parental wild type, whereas npq1 and npq2 mutants affected in xanthophyll carotenoid compositions had identical growth under fluctuating and constant light. Overall, LHCSR3 rather than total qE capacity or zeaxanthin is shown to be important in C. reinhardtii in tolerating fluctuating light, potentially via preventing PSI photoinhibition.

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25

Huang, Kuo-Chen. "Effects of Colored Light and Colors of Comparison Stimulus and Their Background on Heaviness of Lifted Weight". Perceptual and Motor Skills 107, n.º 2 (octubre de 2008): 513–22. http://dx.doi.org/10.2466/pms.107.2.513-522.

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The effects of colored light and colors of stimuli and their backgrounds on participants' perceptions that the weight of a stimulus was identical to a standard weight were examined. A total of 23 women and 19 men, Taiwanese college students ages 20 to 23 years ( M = 21.2, SD= 0.8) were randomly divided into three groups, with each assigned to one of three possible colored light conditions. Colored light significantly affected the constant errors between weight perceptions of the comparison and standard stimuli; the perception constant errors under yellow light were significantly less than those under red and blue lights, and the constant errors under red light were less than those under blue light. Stimulus color significantly affected the constant errors, which were significantly greater for white, yellow, red, and blue comparison stimuli than for black stimuli; the constant errors were significantly greater for white and yellow stimuli than for red and blue. Moreover, an interactive two-way effect of stimulus color and colored light was detected; however, no significant effect of color of stimulus background on constant error was observed. Practical applications include development of safe lifting guidelines and package and product design.

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26

Kasajima, Shin-ya, Naoto Inoue, Rezwanul Mahmud, Kaori Fujita y Masakazu Kato. "Effect of Light Quality on Developmental Rate of Wheat under Continuous Light at a Constant Temperature". Plant Production Science 10, n.º 3 (enero de 2007): 286–91. http://dx.doi.org/10.1626/pps.10.286.

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27

Fortier, François-Xavier y Sylvain G. Cloutier. "Constant-Stress Accelerated Degradation Life Test of an Organic Light-Emitting Diode Display under Violet Light". Engineering 08, n.º 02 (2016): 45–51. http://dx.doi.org/10.4236/eng.2016.82005.

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28

Lubin, Robert T., A. W. Rourke y Richard L. Saunders. "Influence of Photoperiod on the Number and Ultrastructure of Gill Chloride Cells of the Atlantic Salmon (Salmo salar) before and during Smoltification". Canadian Journal of Fisheries and Aquatic Sciences 48, n.º 7 (1 de julio de 1991): 1302–7. http://dx.doi.org/10.1139/f91-156.

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Atlantic salmon (Salmo salar) larger than 9 cm held under constant light since October had greater numbers of gill chloride cells in February compared with fish held under simulated natural photoperiod. By April, fish raised under simulated natural photoperiod were able to survive salinity tests, had a threefold increase in Na+/K+ ATPase activity, and had increased chloride cell numbers. These increases and salinity tolerance did not occur in fish raised under constant light. Only fish reared under constant light developed apical pits with large and numerous microvilli.

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29

Rosenberg, Yael, Tirza Doniger, Saki Harii, Frederic Sinniger y Oren Levy. "Demystifying Circalunar and Diel Rhythmicity in Acropora digitifera under Constant Dim Light". iScience 22 (diciembre de 2019): 477–88. http://dx.doi.org/10.1016/j.isci.2019.11.040.

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30

Nojima, Kazuo, Hideo Saito, Kuniaki Otsuka y Haruo Watanabe. "Circadian rhythm in third generation rats bred under a constant light schedule". Journal of the Autonomic Nervous System 41, n.º 3 (diciembre de 1992): 244. http://dx.doi.org/10.1016/0165-1838(92)90101-l.

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31

Shin, C. N., G.-Y. Rhee y J. Chen. "Phosphate Requirement, Photosynthesis, and Diel Cell Cycle of Scenedesmus obliquas Under Fluctuating Light". Canadian Journal of Fisheries and Aquatic Sciences 44, n.º 10 (1 de octubre de 1987): 1753–58. http://dx.doi.org/10.1139/f87-214.

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The effect of light fluctuation (0.06 Hz) on P requirement, photosynthesis, and the diel cell-division cycle was investigated in Scenedesmus obliquus in a chemostat under a 12 h day: 12 h night cycle. P requirement was much less under oscillating than under constant daylight of the same photon flux density. However, cell chlorophyll a was significantly higher, indicating an increased N requirement. There was little difference in photosynthetic efficiency (the slope of the photosynthesis–light regression) between oscillating and constant light, but photosynthetic capacity was higher in fluctuating light. Cell C was also higher. A strong diel rhythmicity in steady-state cell numbers was observed with little phase difference between oscillating and constant light. Although steady-state cell numbers under P limitation were significantly higher under fluctuating light, there was no difference in instantaneous growth rates and their diel distribution. At a dilution rate of 0.6∙d−1, cell death occurred at an average rate of −0.56∙d−1 between 4 h before and 5 h after the onset of the dark period.

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32

Ramos, Shayenne Elizianne, Luis David Solis Murgas, Monica Rodrigues Ferreira y Carlos Alberto Mourao Junior. "Learning and Working Memory In Mice Under Different Lighting Conditions". Revista Neurociências 21, n.º 3 (30 de septiembre de 2013): 349–55. http://dx.doi.org/10.34024/rnc.2013.v21.8158.

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Objective. This study aimed to investigate the effect of different light/ dark cycles and light intensity during behavioral tests of learning and working memory in Swiss mice. Method. Fifty-seven Swiss mice were kept in a housing room in either a 12:12h light/dark cycle (LD), constant light (LL), or constant darkness (DD). The animals were then tested in Lashley maze and Object recognition task under either 500 or 0 lux illumination, resulting in six treatments (LD-500, LD-0, LL- 500, LL-0, DD-500, and DD-0). Results. There were no significant differences between the conditions of light/dark, or between tests at 500 and 0 lux. Animals kept in constant darkness and tested at 0 lux (DD-0) had learning and working memory impaired, as demonstrated by slower learning in Lashley III maze, and no object recognition in Object recognition task. Conclusion. Continuous darkness throughout the experiment affected the learning and working memory of Swiss mice.

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33

Kujur, Pratibha. "Locomotor activity rhythm of catfish Heteropneustes fossilis are prominently regulated by light-dark cues". South Asian Journal of Experimental Biology 11, n.º 2 (15 de abril de 2021): 128–35. http://dx.doi.org/10.38150/sajeb.11(2).p128-135.

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It is interesting to explore, the circadian locomotor activity rhythm of dark adapted fishes. Therefore, it is aimed to investigate the circadian locomotor activity rhythm of catfish, Heteropneustes fossilis under different light regi-mens- light-dark condition LD 12:12, constant dark condition DD, constant light LL and dark-light condition DL 12:12 in both male and female. The study was conducted sequentially under LD 12: 12 (LON 0500 and LOFF 1700) and thereafter under the DD, LL and DL each for at least 10-12 consecutive days. The locomotor activity was monitored using Stanford Chronobiology Kit at a fixed period of 24 h. The three rhythm parameters obtained were Mesor (M, rhythm-adjusted 24-h average), amplitude (A) and acrophase (peak, Ø). All fish exhibited a statistically significant (p<0.001) circadian rhythm in locomo-tor activity under all light regimens LD, DD, LL and DL. The circadian ampli-tude was significantly declined under constant DD and LL. A significant shift was displayed in the circadian acrophase in all fish under each photic re-gimes LD, DD, LL and DL. The effect of light condition on M, A and Ø was sig-nificant, while gender imposed no effect. Chi-square periodogram revealed τ > 24 h in locomotor activity of most of the replicates under DD and LL. The respective study suggests that the endogenous circadian clocks in catfish H.fossilis are weakly expressed under constant conditions and requires light-dark LD or dark- light DL cues to generate/express the circadian rhythm in locomotor activity.

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34

Adachi, Akihito A., Atsuko Fujioka, Mamoru Nagano, Koh-hei Masumoto, Toru Takumi, Takashi Yoshimura, Shizufumi Ebihara, Kentaro Mori, Yoshifumi Yokota y Yasufumi Shigeyoshi. "Helix-loop-helix Protein Id2 Stabilizes Mammalian Circadian Oscillation Under Constant Light Conditions". Zoological Science 30, n.º 12 (diciembre de 2013): 1011–18. http://dx.doi.org/10.2108/zsj.30.1011.

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35

Cambras, T., M. M. Canal, A. Torres, J. Vilaplana y A. Diez-Noguera. "Manifestation of circadian rhythm under constant light depends on lighting conditions during lactation". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 272, n.º 4 (1 de abril de 1997): R1039—R1046. http://dx.doi.org/10.1152/ajpregu.1997.272.4.r1039.

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Adult rats transferred to continuous illumination (LL) show a disruption of circadian rhythms, although the mechanisms underlying this effect are not yet well known. In previous experiments, we found that when rats were born and raised under LL they showed an ultradian pattern during the first 10 days after weaning, but afterward they generated a circadian rhythm that was maintained until adulthood. It was not clear whether this evolution was attributable to the influence of the rhythm of the mother or to the effect of constant light. Here, we have studied the motor activity rhythm of young rats maintained under LL after weaning, taking into account the conditions to which they were exposed during lactation [LL or continuous darkness (DD)]. To check the possible effect of the rhythm of the dam, on the day of delivery some of the dams were blinded, others were subjected to a restricted feeding schedule of 3 h/day, and the others were used as controls. For each rat, the period of the circadian rhythm and the percentage of variance explained by this rhythm were calculated. Results show that all rats maintained under LL during lactation expressed a circadian rhythm in their motor activity. However, rats maintained under DD during lactation did not. This effect did not seem to be dependent on the type of dam. These results suggest that the rhythm of the dams does not affect the manifestation of the rhythm of the pups and that the expression of circadian rhythmicity under constant bright light depends on the lighting conditions under which the animals were maintained during lactation, which could affect the development of the circadian pacemaker or the retina.

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36

Miyazaki, Yosuke y Hideharu Numata. "Exhibition of circannual rhythm under constant light in the varied carpet beetleAnthrenus verbasci". Biological Rhythm Research 41, n.º 6 (diciembre de 2010): 441–48. http://dx.doi.org/10.1080/09291010903411443.

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37

Namyatov, I. G. y V. I. Babushok. "Critical conditions for explosive decomposition of ozone under UV light of constant intensity". Combustion, Explosion, and Shock Waves 32, n.º 3 (mayo de 1996): 270–75. http://dx.doi.org/10.1007/bf01998455.

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38

Jang, Y. H., C. Lee, B. G. Yoon y H. R. Park. "Light-induced defect generation in hydrogenated amorphous silicon under the constant photocurrent conditions". Solid State Communications 82, n.º 4 (abril de 1992): 283–86. http://dx.doi.org/10.1016/0038-1098(92)90642-m.

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39

Diatroptov, M. E. "Infradian Modulation of Circadian Rhythm in Small Mammals and Birds under Constant Light". Bulletin of Experimental Biology and Medicine 170, n.º 6 (abril de 2021): 795–98. http://dx.doi.org/10.1007/s10517-021-05157-9.

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40

Cushman, K. E. y T. W. Tibbitts. "125 THE ROLE OF ETHYLENE IN THE DEVELOPMENT OF CONSTANT-LIGHT INJURY OF POTATO". HortScience 29, n.º 5 (mayo de 1994): 446c—446. http://dx.doi.org/10.21273/hortsci.29.5.446c.

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Chlorosis and necrotic spotting develop on expanding leaves of particular cultivars of potato (Solanum tuberosum L.) when grown under constant light and temperature conditions. Plantlets of a constant-light sensitive cultivar, Kennebec, were planted into peat:vermiculite and established at 18C for 10 d under a 12 h light: 12 h dark photoperiod. Plants were then exposed to constant light and sprayed with 1 ml of either 0.5 mM silver thiosulfate (STS), an ethylene-action inhibitor, or water (as a control) every 2 days. Specific `target' leaflets, 5-10 mm in length at the beginning of the constant-light period, were harvested on days 5-9 of constant light, during injury development, and placed in bags made of Teflon film for IO-15 minutes to collect ethylene. Ethylene release and necrotic spotting increased as days of constant light increased for both water and STS-treated leaves, though STS-treated leaves produced slightly less ethylene and significantly less necrotic spotting than water-treated leaves. Ethylene release was correlated with extent of necrotic spotting. STS-treated plants exhibited greater dry weight and leaf area then water-treated plants. The results indicate that ethylene is not only produced by injured leaf tissue but, in addition, that ethylene may have a role in the development of constant-light injury symptoms.

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41

PORKKA-HEISKANEN, T., M. L. LAAKSO, D. STENBERG, M. PEDER y G. JOHANSSON. "Testosterone elevates pituitary prolactin content of long-term castrated rats under constant but not under periodic light". Acta Physiologica Scandinavica 140, n.º 2 (octubre de 1990): 279–85. http://dx.doi.org/10.1111/j.1748-1716.1990.tb08999.x.

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42

Dörr, Saskia y Christa Neumeyer. "The Goldfish—A Colour-Constant Animal". Perception 25, n.º 2 (febrero de 1996): 243–50. http://dx.doi.org/10.1068/p250243.

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A series of either thirteen or fifteen coloured test fields with hues from blue through grey to yellow were presented on a black background. Goldfish were trained on a bluish-grey test field by food reward. In the training situation, the setup with the coloured papers was illuminated with white light. In the test situation, the colour of the illumination was changed to blue or yellow. In both test illuminations the goldfish preferred the training field in the same way as under white illumination despite the fact that this test field stimulated the cone types very differently from the training situation. As test fields were present that excited the cones in exactly the same way as under white light, but were not chosen, colour constancy can be concluded. By means of colour metrics, it was possible to quantify direction and strength of colour constancy.

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43

Hoppe, Clara J. M., Lena‐Maria Holtz, Scarlett Trimborn y Björn Rost. "Ocean acidification decreases the light‐use efficiency in an A ntarctic diatom under dynamic but not constant light". New Phytologist 207, n.º 1 (24 de febrero de 2015): 159–71. http://dx.doi.org/10.1111/nph.13334.

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44

Yang, Chao-Hui, Chung-Feng Hwang, Jiin-Haur Chuang, Wei-Shiung Lian, Feng-Sheng Wang, Ethan I. Huang y Ming-Yu Yang. "Constant Light Dysregulates Cochlear Circadian Clock and Exacerbates Noise-Induced Hearing Loss". International Journal of Molecular Sciences 21, n.º 20 (13 de octubre de 2020): 7535. http://dx.doi.org/10.3390/ijms21207535.

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Noise-induced hearing loss is one of the major causes of acquired sensorineural hearing loss in modern society. While people with excessive exposure to noise are frequently the population with a lifestyle of irregular circadian rhythms, the effects of circadian dysregulation on the auditory system are still little known. Here, we disturbed the circadian clock in the cochlea of male CBA/CaJ mice by constant light (LL) or constant dark. LL significantly repressed circadian rhythmicity of circadian clock genes Per1, Per2, Rev-erbα, Bmal1, and Clock in the cochlea, whereas the auditory brainstem response thresholds were unaffected. After exposure to low-intensity (92 dB) noise, mice under LL condition initially showed similar temporary threshold shifts to mice under normal light–dark cycle, and mice under both conditions returned to normal thresholds after 3 weeks. However, LL augmented high-intensity (106 dB) noise-induced permanent threshold shifts, particularly at 32 kHz. The loss of outer hair cells (OHCs) and the reduction of synaptic ribbons were also higher in mice under LL after noise exposure. Additionally, LL enhanced high-intensity noise-induced 4-hydroxynonenal in the OHCs. Our findings convey new insight into the deleterious effect of an irregular biological clock on the auditory system.

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45

Yue, Li Hong y Yi Peng Yang. "Study on Light Intensity Attenuation Characteristics of Chlorella Sp. Culture and the Growth of Chlorella Sp. with the Gradient Light Illuminate Culture". Applied Mechanics and Materials 675-677 (octubre de 2014): 86–89. http://dx.doi.org/10.4028/www.scientific.net/amm.675-677.86.

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Based on the photoautotrophic characteristics of the freshwater microalage, light intensity attenuation characteristics in the cell culture system for Chlorella sp. were studied. Micralgae was cultured with a constant and the gradient light illuminate culture conditions, the cell growth of Microlagae was detected respectively, By means of regression analysis, mathematical models of illuminance intensity attenuation are gotten under different culture conditions. Results show algae cell density under gradient light culture conditions is higher than constant light, so the gradient light is more suitable for the cultivation of microalgae.

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46

Ekiert, Halina y Ewa Gomółka. "Effect of light on contents of coumarin compounds in shoots of Ruta graveolens L. cultivated in vitro". Acta Societatis Botanicorum Poloniae 68, n.º 3 (2014): 197–200. http://dx.doi.org/10.5586/asbp.1999.026.

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Shoots of <em>Ruta graveolens</em> L. (<em>Rutaceae</em>) were cultivated in stationary liquid culture under different light conditions: constant artificial light (900 lx), darkness, constant artificial light (900 ix) following irradiation with UV-C light. The contents of five furanocoumarins: psoralen, bergapten, xanthotoxin, isopimpinellin and imperatorin, as well as biogenetic precursor of these metabolites, umbelliferone, were determined by HPLC method in shoots cultivated in vitro and in overground parts of plants growing in open air. It was shown that light conditions, tested in these experiments, significantly influenced contents of the metabolites in shoots cultivated in in vitro culture. Total content of the coumarin compounds in shoots cultivated under constant artificial light (900 lx) was equal or higher than in plants growing under natural conditions. Therefore, it is suggested that stationary liquid shoot culture of <em>R. graveolens</em>. can be an alternative source for obtaining biologically active furanocoumarins.

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47

Bardonnet, Agnès y Philippe Gaudin. "Influence of Daily Variations of Light and Temperature on the Emergence Rhythm of Grayling Fry (Thymallus thymallus)". Canadian Journal of Fisheries and Aquatic Sciences 48, n.º 7 (1 de julio de 1991): 1176–80. http://dx.doi.org/10.1139/f91-141.

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The emergence rhythm of grayling fry (Thymallus thymallus) was studied in four aquaria fitted with traps under four different conditions of light and temperature. Both light and temperature induced an emergence rhythm characterized by a 24-h period. Under ambient Sight and constant temperature, emergence peaked at the end of the night before the onset of dawn. Under constant dim light and varying temperature, emergence peaked in early morning during the coldest hours. When both light and temperature fluctuated daily the emergence pattern was equivalent to the "sum" of these previous two regimes and was similar to that described in the field in a previous report. In the absence of light and temperature variations, no emergence rhythm was observed.

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48

Butler, T. M., S. R. Narayan, S. U. Mooers y M. J. Siegman. "Rapid turnover of myosin light chain phosphate during cross-bridge cycling in smooth muscle". American Journal of Physiology-Cell Physiology 267, n.º 4 (1 de octubre de 1994): C1160—C1166. http://dx.doi.org/10.1152/ajpcell.1994.267.4.c1160.

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The rate of phosphatase-mediated dephosphorylation of the regulatory light chain of smooth muscle myosin was determined under nearly steady-state conditions in permeabilized muscles, from the time course of incorporation of 33P-labeled phosphate into the light chain after the photolytic release of [gamma-33P]ATP from high specific activity caged [gamma-33P]ATP. The extent of myosin light chain phosphorylation is unchanged, and, if the kinase and phosphatase reactions are irreversible, the rate constant for the exponential increase in 33P in the light chain is equal to the rate constant for the phosphatase reaction. Under activated conditions (pCa 4.5) at 20 degrees C, the incorporation of 33P into approximately 80% of the phosphorylated light chain is fit by a single exponential with a rate constant of 0.37 s-1. ATP usage due to phosphorylation and dephosphorylation of the light chain is about one-third of the suprabasal energy requirement. The high phosphatase rate constant suggests that dephosphorylation of the light chain is rapid enough to interact with and potentially modify the completion of the cross-bridge cycle.

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49

Zhao, Kankan, Bin Ma, Yan Xu, Erinne Stirling y Jianming Xu. "Light exposure mediates circadian rhythms of rhizosphere microbial communities". ISME Journal 15, n.º 9 (21 de marzo de 2021): 2655–64. http://dx.doi.org/10.1038/s41396-021-00957-3.

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AbstractMicrobial community circadian rhythms have a broad influence on host health and even though light-induced environmental fluctuations could regulate microbial communities, the contribution of light to the circadian rhythms of rhizosphere microbial communities has received little attention. To address this gap, we monitored diel changes in the microbial communities in rice (Oryza sativa L.) rhizosphere soil under light–dark and constant dark regimes, identifying microbes with circadian rhythms caused by light exposure and microbial circadian clocks, respectively. While rhizosphere microbial communities displayed circadian rhythms under light–dark and constant dark regimes, taxa possessing circadian rhythms under the two conditions were dissimilar. Light exposure concealed microbial circadian clocks as a regulatory driver, leading to fewer ecological niches in light versus dark communities. These findings disentangle regulation mechanisms for circadian rhythms in the rice rhizosphere microbial communities and highlight the role of light-induced regulation of rhizosphere microbial communities.

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50

Hong, Yunkyung, Yunho Jin, Kanghui Park, Jeonghyun Choi, Hyunbon Kang, Sang-Rae Lee y Yonggeun Hong. "Elevated Serum Melatonin under Constant Darkness Enhances Neural Repair in Spinal Cord Injury through Regulation of Circadian Clock Proteins Expression". Journal of Clinical Medicine 8, n.º 2 (23 de enero de 2019): 135. http://dx.doi.org/10.3390/jcm8020135.

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We investigated the effects of environmental lighting conditions regulating endogenous melatonin production on neural repair, following experimental spinal cord injury (SCI). Rats were divided into three groups randomly: the SCI + L/D (12/12-h light/dark), SCI + LL (24-h constant light), and SCI + DD (24-h constant dark) groups. Controlled light/dark cycle was pre-applied 2 weeks before induction of spinal cord injury. There was a significant increase in motor recovery as well as body weight from postoperative day (POD) 7 under constant darkness. However, spontaneous elevation of endogenous melatonin in cerebrospinal fluid was seen at POD 3 in all of the SCI rats, which was enhanced in SCI + DD group. Augmented melatonin concentration under constant dark condition resulted in facilitation of neuronal differentiation as well as inhibition of primary cell death. In the rostrocaudal region, elevated endogenous melatonin concentration promoted neural remodeling in acute phase including oligodendrogenesis, excitatory synaptic formation, and axonal outgrowth. The changes were mediated via NAS-TrkB-AKT/ERK signal transduction co-regulated by the circadian clock mechanism, leading to rapid motor recovery. In contrast, exposure to constant light exacerbated the inflammatory responses and neuroglial loss. These results suggest that light/dark control in the acute phase might be a considerable environmental factor for a favorable prognosis after SCI.

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