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Diurnal variation

Alicia Garzón-Ariza, Alicia Guisado, Alba Galán, Eva Martín-Suárez
OBJECTIVE: To study the diurnal variation in intraocular pressure (IOP) and central corneal thickness (CCT) in healthy Beagles by rebound tonometry and ultrasonic pachymetry, respectively, in addition to determining whether a correlation exists between these two variables. ANIMALS STUDIED: Twenty eyes from 10 healthy Beagle dogs were included in the study. PROCEDURES: The IOP and CCT were measured by rebound tonometry and ultrasonic pachymetry, respectively, at 2-h intervals over an 8-hour period between 10:00 and 18:00...
December 12, 2017: Veterinary Ophthalmology
Christine M Swanson, Wendy M Kohrt, Orfeu M Buxton, Carol A Everson, Kenneth P Wright, Eric S Orwoll, Steven A Shea
Adequate sleep timed appropriately during the circadian night is important for numerous biological processes and systems. New evidence suggests that both sleep timing and duration may be important for optimal bone health as well. This review examines the diurnal variation of bone turnover markers (BTMs) and the importance of circadian clock genes in regulating bone mass. In addition, this review explores the evidence for a link between shift work (and its associated disturbances in sleep duration/quality and circadian alignment) and alterations in bone metabolism and bone health...
December 8, 2017: Metabolism: Clinical and Experimental
Palakolanu Sudhakar Reddy, Murugesan Tharanya, Kaliamoorthy Sivasakthi, Mallayee Srikanth, C Tom Hash, Jana Kholova, Kiran K Sharma, Vincent Vadez
Pearl millet is a crop of the semi-arid tropics having high degree of genetic diversity and variable tolerance to drought stress. To investigate drought tolerance mechanism that possibly accounts for differences in drought tolerance, four recombinant inbred lines from a high resolution cross (HRC) were selected for variability in their transpiration rate (Tr) response to vapour pressure deficit (VPD) conditions. The differential Tr response of the genotypes to increased VPD conditions was used to classify the genotypes as sensitive or insensitive to high VPD...
December 2017: Plant Science: An International Journal of Experimental Plant Biology
Viktor Kalinchuk, Evgeny Lopatnikov, Anatoly Astakhov
Gaseous elemental mercury (Hg0) is a prolific and persistent contaminant in the atmosphere. Atmospheric concentrations of Hg0 were determined from 17 September to 7 October 2015 in the northwest Sea of Japan aboard the Russian research vessel Professor Gagarinsky. Simultaneous measurements of Hg0 concentrations were performed 2 m and 20 m above the sea surface using automatic Hg0 analysers RA-915M and RA-915+, respectively. Concentrations ranged from 0.3 to 25.9 ng/m3 (n = 5207) and from 0.3 to 27.8 ng/m3 (n = 4415), with medians of 1...
December 6, 2017: Environmental Pollution
Raphael Felber, Sibylle Stoeckli, Pierluigi Calanca
Accumulated growing degree-days (aGDD) are widely used to predict phenological stages of plants and insects. It has been shown in the past that the best predictive performance is obtained when aGDD are computed from hourly temperature data. As the latter are not always available, models of diurnal temperature changes are often employed to retrieve the required information from data of daily minimum and maximum temperatures. In this study, we examine the performance of a well-known model of hourly temperature variations in the context of a spatial assessment of aGDD...
December 7, 2017: International Journal of Biometeorology
Meiling Gao, Huanfeng Shen, Xujun Han, Huifang Li, Liangpei Zhang
Urban heat islands (UHIs) are the phenomenon of urban regions usually being warmer than rural regions, which significantly impacts both the regional ecosystem and societal activities. Numerical simulation can provide spatially and temporally continuous datasets for UHI analysis. In this study, a spatially and temporally continuous ground temperature dataset of Xi'an, China was obtained through numerical simulation based on the Community Land Model version 4.5 (CLM4.5), at a temporal resolution of 30 min and a spatial resolution of 0...
December 6, 2017: Environmental Monitoring and Assessment
Karin Richter, Isabelle Schmutz, Mahesh Darna, Johannes-F Zander, Rohit Chavan, Urs Albrecht, Gudrun Ahnert-Hilger
Glutamate is concentrated into synaptic vesicles (SV) by the vesicular glutamate transporters (VGLUT) 1and 2. VGLUTs also harbour a Na+/Pi -transport activity when residing at the plasma membrane. Here we aimed to identify whether the diurnal switches of VGLUT1 parallels interactions with or modification of endocytic proteins VGLUT1 and dynamin bind to SH3 domains of either endophilin (Enph) or intersectin 1 (ITSN1) harbouring one or five SH3 domains A-E, respectively. We followed diurnal variations by pull down experiments using SH3 fusion protein and brains from mice entrained in a strict 24 h light dark cycle (12 h light Zeitgeber (ZT) 0, 6; 12 h dark ZT 12 and 18)...
November 30, 2017: Neuroscience
Niels E Kirkhus, Øivind Skare, Bente Ulvestad, Trond Mogens Aaløkken, Anne Günther, Raymond Olsen, Yngvar Thomassen, May Brit Lund, Dag G Ellingsen
PURPOSE: The aim of this study was to assess short-term changes in pulmonary function in drill floor workers currently exposed to airborne contaminants generated as a result of drilling offshore. We also aimed to study the prevalence of pulmonary fibrosis using high-resolution computed tomography (HRCT) scans of another group of previously exposed drill floor workers. METHODS: Pulmonary function was measured before and after a 14-day work period in a follow-up study of 65 drill floor workers and 65 referents...
December 1, 2017: International Archives of Occupational and Environmental Health
James O Sanders, Xing Qiu, Xiang Lu, Dana L Duren, Raymond W Liu, Debbie Dang, Mariano E Menendez, Sarah D Hans, David R Weber, Daniel R Cooperman
Humans are one of the few species undergoing an adolescent growth spurt. Because children enter the spurt at different ages making age a poor maturity measure, longitudinal studies are necessary to identify the growth patterns and identify commonalities in adolescent growth. The standard maturity determinant, peak height velocity (PHV) timing, is difficult to estimate in individuals due to diurnal, postural, and measurement variation. Using prospective longitudinal populations of healthy children from two North American populations, we compared the timing of the adolescent growth spurt's peak height velocity to normalized heights and hand skeletal maturity radiographs...
December 1, 2017: Scientific Reports
Benjamin Y Xu, Rafaella Cleto Penteado, Robert Neal Weinreb
PURPOSE: To examine the diurnal variation of static and dynamic anterior segment parameters in young, healthy eyes by comparing anterior segment optical coherence tomography (AS-OCT) measurements obtained in the morning and evening and also in the light and dark. METHODS: Twenty-two subjects ranging from ages 19 to 47 years with no past ocular history were selected (12 male, 10 female; mean age 34.2 y). Imaging was performed with the Tomey CASIA2 AS-OCT device in two fixed lighting environments, light and dark, between the hours of 0830 to 1000 and 1730 to 1900...
November 30, 2017: Journal of Glaucoma
Thomas W DeCato, Sean M Bradley, Emily L Wilson, Matthew J Hegewald
INTRODUCTION/PURPOSE: Cardiopulmonary exercise testing (CPET) plays an important role in clinical medicine and research. Repeatability of CPET parameters has not been well characterized, but is important to assess variability and determine if there have been meaningful changes in a given CPET parameter. METHODS: We recruited 45 healthy subjects and performed two symptom-limited CPETs within 30 days using a cycle ergometer. Differences in relevant CPET parameters between CPET-1 and CPET-2 were assessed using a paired t-test...
November 7, 2017: Medicine and Science in Sports and Exercise
Salih Uzun, Emre Pehlivan, Mehmet Gulmez
No abstract text is available yet for this article.
2017: International Journal of Ophthalmology
Muralidhar Gollapalli, Sri Harsha Kota
Rapid urbanization and economic growth has led to significant increase in municipal solid waste generation in India during the last few decades and its management has become a major issue because of poor waste management practices. Solid waste generated is deposited into open dumping sites with hardly any segregation and processing. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are the major greenhouse gases that are released from the landfill sites due to the biodegradation of organic matter...
November 22, 2017: Environmental Pollution
Stefanos Nikolaidis, Ioannis Kosmidis, Michail Sougioultzis, Athanasios Kabasakalis, Vassilis Mougios
The postexercise urine lactate concentration is a novel valid exercise biomarker, which has exhibited satisfactory reliability in the morning hours under controlled water intake. The aim of the present study was to investigate the diurnal variation of the postexercise urine lactate concentration and its reliability in the afternoon hours. Thirty-two healthy children (11 boys and 21 girls) and 23 adults (13 men and 10 women) participated in the study. All participants performed two identical sessions of eight 25 m bouts of maximal freestyle swimming executed every 2 min with passive recovery in between...
November 27, 2017: Chronobiology International
Rui Zhang, Wiebke Schrempf, Moritz D Brandt, Moritz Mückschel, Christian Beste, Ann-Kathrin Stock
OBJECTIVE: The restless legs syndrome (RLS) is characterized by sensory-motor symptoms which usually occur predominantly at rest in the evening and at night. It is assumed that this circadian rhythm is caused by low dopamine levels in the evening. Yet, it has never been investigated whether RLS patients show diurnal variations in cognitive functions modulated by dopamine and what neurophysiological and functional neuroanatomical processes underlie such modulations. METHODS: We used a Simon task combined with EEG and source localization to investigate whether top-down response selection and/or automatic visuo-motor priming are subject to diurnal changes in RLS patients, as compared to matched healthy controls...
November 6, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Denise Ma, Lisa A Serbin, Dale M Stack
Anxiety can impact the immune system resulting in negative health outcomes. Salivary immunoglobulin A (sIgA) is a first line of defense against foreign antigens, with lowered levels indicative of weakened mucosal immunity. Little is known about how anxiety symptoms affect the diurnal rhythm of sIgA secretion, or the longitudinal transactional sequence between the two in children and adolescents. The goals of the two studies were to: (i) explore the concurrent associations between self-reported anxiety symptoms and diurnal variations of sIgA across the day using repeated daily samples of sIgA; and (ii) examine transactional relations between children's anxiety and aggregated total amount of sIgA levels across successive periods from middle childhood (Wave 1; ages 9-12) to early adolescence (Wave 2; ages 12-15), and from early to mid- adolescence (Wave 3; ages 15-18)...
November 24, 2017: Developmental Psychobiology
Denis Monneret, Jean-Claude Barthélémy, David Hupin, Delphine Maudoux, Sébastien Celle, Emilia Sforza, Frédéric Roche
OBJECTIVES: Dyslipidemia, sleep-disordered breathing (SDB) and hypertension are comorbid factors evidenced in adults, but poorly studied in old people. This study aimed to examine the long-term evolution of the serum lipid profile, and its relationships with SDB and blood pressure (BP) in the elderly. METHODS: A ten-year follow-up of the prospective Prognostic Indicator of Cardiovascular and Cerebrovascular Events (PROOF) and the Autonomic Nervous System Activity, Aging and Sleep Apnea/Hypopnea (SYNAPSE) cohort, which initially included 1011 elderly subjects from the general population, and who were untreated by continuous positive airway pressure (CPAP)...
November 2017: Sleep Medicine
Halszka Oginska, Justyna Mojsa-Kaja, Olivier Mairesse
The term "subjective circadian amplitude" refers to the range or the distinctness of diurnal variations of arousal, that is, the awareness (or lack thereof) of difference between hyper- and hypo-activation phases, the ability to volitionally modulate one's own psychophysiological state, the strength of morning-evening preferences and flexibility of the rhythm or perceived stability of the circadian phase. The complexity of this construct is the source of difficulties in research and measurement. The psychometric features of distinctness subscales of the Chronotype Questionnaire and the Caen Chronotype Questionnaire are not satisfactory...
November 20, 2017: Chronobiology International
Baozhu Ge, Zifa Wang, Weili Lin, Xiaobin Xu, Jie Li, Dongshen Ji, Zhiqiang Ma
High concentrations of the fine particles (PM2.5) are frequently observed during all seasons over the North China Plain (NCP) region in recent years. In NCP, the contributions of regional transports to certain area, e.g. Beijing city, are often discussed and estimated by models when considering an effective air pollution controlling strategy. In this study, we selected three sites from southwest to northeast in NCP, in which the concentrations of air pollutants displayed a multi-step decreasing trend in space...
November 17, 2017: Environmental Pollution
Harriet C P Lau, Jerry X Mitrovica, James L Davis, Jeroen Tromp, Hsin-Ying Yang, David Al-Attar
Earth's body tide-also known as the solid Earth tide, the displacement of the solid Earth's surface caused by gravitational forces from the Moon and the Sun-is sensitive to the density of the two Large Low Shear Velocity Provinces (LLSVPs) beneath Africa and the Pacific. These massive regions extend approximately 1,000 kilometres upward from the base of the mantle and their buoyancy remains actively debated within the geophysical community. Here we use tidal tomography to constrain Earth's deep-mantle buoyancy derived from Global Positioning System (GPS)-based measurements of semi-diurnal body tide deformation...
November 15, 2017: Nature
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