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Purpose: The objective of this study was to investigate the effects of morning versus evening plyometric training (PT) on performance adaptations in male volleyball players. Methods: A total of 30 collegiate national-level young male volleyball players (age = 21.9 [2.1]; height = 186 [4.1]; body mass = 82.4 [4.6]) were randomly divided into 3 groups: morning PT (MPT), evening PT (EPT), and an active control group, each group consisting of 10 subjects. The players engaged in PT sessions twice weekly for a period of 6 weeks. The evaluation of biomotor abilities such as countermovement vertical jump, standing long jump, spike jump, block jump, 10-m sprint, T-test, sit and reach, and Y-balance test took place in the morning and evening before and after the intervention. Results: Both the MPT and EPT groups indicated significant (P <.05) improvements in all biomotor abilities from pretraining to posttraining during both the morning and evening testing sessions. Furthermore, the MPT group displayed greater adaptive responses in the vertical jump (P =.001), standing long jump (P =.023), and Y-balance test (P ≤.01) compared to the EPT group. Time-of-day fluctuations were the same between the MPT and EPT groups at the pretest. Conversely, EPT demonstrated significantly more daytime variations than MPT in the jump, sprint, and balance tests at postintervention (P <.05). Conclusion: Engaging in PT at specific times of the day has a significant impact on biomotor ability adaptations, with a focus on morning being more favorable than the evening for achieving greater gains in jump and balance performance of volleyball players. [ABSTRACT FROM AUTHOR]

Purpose: To examine nocturnal sleep patterns, napping behaviors, and subjective wellness responses of elite water polo players within an in-season week and to identify whether sleeping patterns differ between men and women. Methods: Sleep characteristics of 10 male and 17 female professional water polo players were objectively assessed during 1 week of the in-season period, including 5 training days, 1 match day, and 1 day of rest. Internal load (rating of perceived exertion × duration of training or match) was assessed 30 minutes posttraining or postmatch, and the total quality of recovery was recorded every morning. A series of multilevel models were used to analyze the data. Results: Time in bed and wake-up time were earlier on both training (P <.001) and rest days (P <.001) than on the day of the match. Internal workload did not predict any of the players' sleeping patterns. Midday naps predicted less time in bed (P =.03) and likely less sleep time (P =.08). The total quality of recovery was predicted only by the total sleep time (P <.01). Women exhibited higher sleep efficiency (P <.001), less waking after sleep onset (P =.01), and a lower number of awakenings (P =.02) than men. Conclusions: The current results indicate that the nocturnal sleep patterns of elite water polo players are not associated with internal load and that women display better nocturnal sleep quality compared with men. As long naps interfere with nocturnal sleep, and total nocturnal sleep time predicts total quality of recovery, we suggest that athletes follow hygiene sleep strategies to facilitate adequate nocturnal sleep and next-day recovery. [ABSTRACT FROM AUTHOR]

The objective of this 18-month walking intervention was to evaluate the effect on rest–activity rhythm (RAR) for older adults with mild-to-moderate dementia (65.8% female; aged M = 82.4 [SD = 6.5]). The intervention group (n = 44) was intended to walk 30 min, five times per week for 18 months. The control group (n = 35) received sedentary activities or usual care. RAR was measured at baseline to after 18 months and five times in between actigraphy outcome variables (interdaily stability, intradaily variability, relative amplitude, activity 10 most active hours, and activity 5 least active hours). Hierarchical mixed model analyses revealed no significant intervention effects (with or without baseline confounders as covariate) on RAR. However, participants in the intervention group were able to significantly increase their daily life activity (activity 10 most active hours) from the onset of the preceding measurement, b = 0.10, t(239.32) = 2.36, p =.019. More research is warranted to study the effect of regular walks on older persons with dementia whose RAR is worst at baseline. [ABSTRACT FROM AUTHOR]

Casein kinase 1δ (CK1δ) controls essential biological processes including circadian rhythms and wingless-related integration site (Wnt) signaling, but how its activity is regulated is not well understood. CK1δ is inhibited by autophosphorylation of its intrinsically disordered C-terminal tail. Two CK1 splice variants, δ1 and δ2, are known to have very different effects on circadian rhythms. These variants differ only in the last 16 residues of the tail, referred to as the extreme C termini (XCT), but with marked changes in potential phosphorylation sites. Here, we test whether the XCT of these variants have different effects in autoinhibition of the kinase. Using NMR and hydrogen/deuterium exchange mass spectrometry, we show that the δ1 XCT is preferentially phosphorylated by the kinase and the δ1 tail makes more extensive interactions across the kinase domain. Mutation of δ1-specific XCT phosphorylation sites increases kinase activity both in vitro and in cells and leads to changes in the circadian period, similar to what is reported in vivo. Mechanistically, loss of the phosphorylation sites in XCT disrupts tail interaction with the kinase domain. δ1 autoinhibition relies on conserved anion-binding sites around the CK1 active site, demonstrating a common mode of product inhibition of CK1δ. These findings demonstrate how a phosphorylation cycle controls the activity of this essential kinase.

Huntingtons Disease (HD) is a neurodegenerative disorder caused by an autosomal-dominant mutation in the huntingtin gene, which manifests with a triad of motor, cognitive and psychiatric declines. Individuals with HD often present with disturbed sleep/wake cycles, but it is still debated whether altered circadian rhythms are intrinsic to its aetiopathology or a consequence. Conversely, it is well established that sleep/wake disturbances, perhaps acting in concert with other pathophysiological mechanisms, worsen the impact of the disease on cognitive and motor functions and are a burden to the patients and their caretakers. Currently, there is no cure to stop the progression of HD, however, preclinical research is providing cementing evidence that restoring the fluctuation of the circadian rhythms can assist in delaying the onset and slowing progression of HD. Here we highlight the application of circadian-based interventions in preclinical models and provide insights into their potential translation in clinical practice. Interventions aimed at improving sleep/wake cycles synchronization have shown to improve motor and cognitive deficits in HD models. Therefore, a strong support for their suitability to ameliorate HD symptoms in humans emerges from the literature, albeit with gaps in our knowledge on the underlying mechanisms and possible risks associated with their implementation.

Chrononutrition is a rapidly evolving field of nutritional epidemiology that addresses the complex relationship between temporal eating patterns, circadian rhythms, and metabolic health, but most prior research has focused on the cardiometabolic consequences of time-restricted feeding and intermittent fasting. The purpose of this topical review is to summarize epidemiological evidence from observational and intervention studies regarding the role of chrononutrition metrics related to eating timing and regularity in cardiometabolic health preservation and cardiovascular disease prevention. Observational studies are limited due to the lack of time-stamped diet data in most population-based studies. Findings from cohort studies generally indicate that breakfast skipping or the later timing of the first eating occasion, a later lunch and dinner, and a greater proportion of caloric intake consumed in the evening are associated with adverse cardiometabolic outcomes, including higher risk for coronary heart disease, hypertension, type 2 diabetes, obesity, dyslipidemia, and systemic inflammation. Randomized controlled trials are also limited, as most in the field of chrononutrition focus on the cardiometabolic consequences of time-restricted feeding. Overall, interventions that shift eating timing patterns to earlier in the day and that restrict evening caloric intake tend to have protective effects on cardiometabolic health, but small sample sizes and short follow-up are notable limitations. Innovation in dietary assessment approaches, to develop low-cost validated tools with acceptable participant burden that reliably capture chrononutrition metrics, is needed for advancing observational evidence. Culturally responsive pragmatic intervention studies with sufficiently large and representative samples are needed to understand the impact of fixed and earlier eating timing schedules on cardiometabolic health. Additional research is warranted to understand the modifiable determinants of temporal eating patterns, to investigate the role of chrononutrition in the context of other dimensions of diet (quantity, quality, and food and nutrition security) in achieving cardiometabolic health equity, and to elucidate underlying physiological mechanisms.

Purpose: Transmeridian travel is common for elite athletes participating in competitions and training. However, this travel can lead to circadian misalignment wherein the internal biological clock becomes desynchronized with the light–dark cycle of the new environment, resulting in performance decrement and potential negative health consequences. Existing literature extensively discusses recommendations for managing jet lag, predominantly emphasizing light-based interventions to synchronize the internal clock with the anticipated time at the destination. Nevertheless, visually impaired (VI) athletes may lack photoreceptiveness, diminishing or nullifying the effectiveness of this therapy. Consequently, this invited commentary explores alternative strategies for addressing jet lag in VI athletes. Conclusions: VI athletes with light perception but reduced visual acuity or visual fields may still benefit from light interventions in managing jet lag. However, VI athletes lacking a conscious perception of light should rely on gradual shifts in behavioral factors, such as meal timing and exercise, to facilitate the entrainment of circadian rhythms to the destination time. Furthermore, interventions like melatonin supplementation may prove useful during and after travel. In addition, it is recommended that athlete guides adopt phase-forward or phase-back approaches to synchronize with the athlete, aiding in jet-lag management and optimizing performance. [ABSTRACT FROM AUTHOR]

Paradoxical leadership—the integration of leadership behaviors that are seemingly contradictory, but nevertheless interdependent—is becoming increasingly important in today's complex and turbulent business environments. Despite evidence for the positive consequences of paradoxical leadership, little research has examined how and when leaders can effectively integrate or reconcile opposing leadership behaviors. Two of the most fundamental paradoxical challenges that leaders face include the need to integrate control and empowerment, as well as reconciling collective rules with followers' individual needs. In this article, we advance a circadian theory of paradoxical leadership that outlines how leaders can combine episodic thinking with circadian principles to achieve a dynamic equilibrium between the opposing poles of these two leadership paradoxes. Our temporal framework explains how leaders can effectively structure paradoxical leadership episodes that leverage their own and their followers' circadian processes within a broader framework of situation-driven leadership. In doing so, we contribute to future research by providing a novel circadian perspective on how paradoxical tensions in organizations can be reconciled within the constraints of situational demands. [ABSTRACT FROM AUTHOR]

STUDY OBJECTIVES: This single-arm, mixed-methods, pilot study examined the feasibility and preliminary efficacy of an adapted version of the transdiagnostic intervention for sleep and circadian dysfunction (TranS-C) on multidimensional sleep health (MDSH) in a sample of adults with excess weight and suboptimal sleep health. METHODS: Participants received up to eight, weekly, remotely delivered, tailored TranS-C sessions. At pre- and post-intervention, the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and 7 days of Fitbit data were used to evaluate changes in sleep dimensions (regularity, alertness, timing, satisfaction, duration, and efficiency) and the composite MDSH score. Study feasibility examined recruitment, data collection, and intervention engagement (completion of core TranS-C sessions). Acceptability of the intervention was assessed with semi-structured interviews, which were analyzed using thematic analysis. RESULTS: From 85 referrals, 11 individuals were eligible, and 10 completed the study. All intervention participants completed the measures needed to calculate their composite MDSH score and completed the core intervention sessions. Themes from interviews support the interventions remote delivery approach, applicability of the information provided, and impact on self-reported health. The intervention resulted in a large improvement in the mean composite MDSH score (Cohens d = 1.17). Small-to-large effects were also observed for individual sleep health dimensions except for timing. CONCLUSIONS: Adapted TranS-C is acceptable for adults with excess weight and suboptimal sleep health and may be effective at improving short-term MDSH. With changes to recruitment methods, a larger study is feasible. Limitations include the small sample size and the lack of a control condition.

Circadian rhythms are driven by an internal molecular clock which controls physiological and behavioral processes. Disruptions in these rhythms have been associated with health issues. Therefore, studying circadian rhythms is crucial for understanding physiology, behavior, and pathophysiology. However, it is challenging to study circadian rhythms over gene expression data, due to a scarcity of time labels. In this paper, we propose a novel approach to predict the phases of un-timed samples based on a deep neural network (DNN) architecture. This approach addresses two challenges: (1) prediction of sample phases and reliable identification of cyclic genes from high-dimensional expression data without relying on conserved circadian genes and (2) handling small sample-sized datasets. Our algorithm begins with initial gene screening to select candidate cyclic genes using a Minimum Distortion Embedding framework. This stage is then followed by greedy layer-wise pre-training of our DNN. Pre-training accomplishes two critical objectives: First, it initializes the hidden layers of our DNN model, enabling them to effectively capture features from the gene profiles with limited samples. Second, it provides suitable initial values for essential aspects of gene periodic oscillations. Subsequently, we fine-tune the pre-trained network to achieve precise sample phase predictions. Extensive experiments on both animal and human datasets show accurate and robust prediction of both sample phases and cyclic genes. Moreover, based on an Alzheimer's disease (AD) dataset, we identify a set of hub genes that show significant oscillations in cognitively normal subjects but had disruptions in AD, as well as their potential therapeutic targets. [ABSTRACT FROM AUTHOR]

The suprachiasmatic nucleus (SCN) is the master clock that directly dictates behavioural rhythms to anticipate the earth's light/dark cycles. Although post‐transcriptional regulators called microRNAs have been implicated in physiological SCN function, how the absence of the entire mature miRNome impacts SCN output has not yet been explored. To study the behavioural consequences of miRNA depletion in the SCN, we first generated a mouse model in which Dicer is inactivated in the SCN by crossing Syt10Cre mice with Dicerflox mice to study behavioural consequences of miRNA depletion in the SCN. Loss of all mature miRNAs in the SCN shortened the circadian period length by ~37 minutes at the tissue level and by ~45 minutes at the locomotor activity level. Moreover, knockout animals exhibited a reduction in the precision of the circadian rhythm with more variable activity onsets under both LD 12:12 and DD conditions. We also observed that knockouts with higher onset variations were inclined to develop ultradian rhythms under constant light. In a second mouse model, recombination of Dicerflox via Cre delivery specifically in the SCN resulted in loss of behavioural rhythms in some animals depending on the injection efficiency. Together, our observations highlight the importance of microRNAs for a physiological SCN function and their pivotal role in robust circadian oscillations. [ABSTRACT FROM AUTHOR]

Anxiety is being increasingly linked to circadian rhythms, including chronotype, in addition to its intricate links with sleep quality. Emotional competence is thought to be a strong predictor of wellbeing and mental health. This study aimed to examine whether a combination of chronotype, sleep quality, and intrapersonal emotional competence can predict anxiety in emerging adults (aged 18–29), who have the greatest prevalence of adult anxiety. One hundred and seventeen participants completed self-report measures of chronotype, sleep quality, emotional competence, and anxiety. A multiple linear regression, with anxiety as the criterion variable, showed that while all predictors were significant, sleep quality was the strongest predictor of anxiety. A later chronotype, poorer sleep quality and lower intrapersonal emotional competence were related to higher anxiety. Thus, integrating intrapersonal emotional competence and chronotype considerations into interventions may address the interplay between sleep quality and anxiety in emerging adults more effectively. [ABSTRACT FROM AUTHOR]

The ability to anticipate tides is critical for a wide range of marine organisms, but this task is complicated by the diversity of tidal patterns on Earth. Previous findings suggest that organisms whose geographic range spans multiple types of tidal cycles can produce distinct patterns of rhythmic behavior that correspond to the tidal cycles they experience. How this behavioral plasticity is achieved, however, is unclear. Here, we show that Parhyale hawaiensis adapts its rhythmic behavior to various naturally occurring tidal regimens through the plastic contribution of its circatidal and circadian clocks. After entrainment to a tidal cycle that deviated only mildly from a regular 12.4 h tidal cycle, animals exhibited strong circatidal rhythms. By contrast, following entrainment to more irregularly spaced tides or to tides that occurred every 24.8 h, a significant fraction of animals instead synchronized to the light/dark (LD) cycle and exhibited circadian behavior, while others showed rhythmic behavior with both circatidal and circadian traits. We also show that the circatidal clock, while able to entrain to various naturally occurring tidal patterns, does not entrain to an unnatural one. We propose that Parhyale hawaiensis 's ecological success around the world relies in part on the plastic interactions between the circatidal and circadian clocks, which shape its rhythmic behavior appropriately according to tidal patterns. [Display omitted] • P. hawaiensis synchronizes its circatidal behavior to different tidal patterns • Various rhythmic phenotypes emerge when tides are irregular or diurnal • Interactions between circadian and circatidal clock shape rhythmic behavior • Unnatural 17-h tidal cycles do not entrain circatidal behavior Tides usually follow a 12.4 h schedule but can be irregular in duration or occur only once every 24.8 h. Kwiatkowski et al. show that the rhythmic behavior of P. hawaiensis adapts to tidal patterns through plastic crosstalk between its circatidal and circadian clocks. This flexibility might help this crustacean colonize various coastal areas. [ABSTRACT FROM AUTHOR]

Shift work, particularly night shifts, disrupts circadian rhythms and increases stroke risk. This manuscript explores the mechanisms connecting shift work with stroke, focusing on circadian rhythms, hypertension, and diabetes. The circadian system, controlled by different mechanisms including central and peripheral clock genes, suprachiasmatic nuclei (SCN), and pineal gland (through melatonin production), regulates body functions and responds to environmental signals. Disruptions in this system affect endothelial cells, leading to blood pressure issues. Type 2 diabetes mellitus (T2DM) is significantly associated with night shifts, with circadian disturbances affecting glucose metabolism, insulin sensitivity, and hormone regulation. The manuscript examines the relationship between melatonin, insulin, and glucose balance, highlighting pathways that link T2DM to stroke risk. Additionally, dyslipidemia, particularly reduced HDL-c levels, results from shift work and contributes to stroke development. High lipid levels cause oxidative stress, inflammation, and endothelial dysfunction, increasing cerebrovascular risks. The manuscript details the effects of dyslipidemia on brain functions, including disruptions in blood flow, blood–brain barrier integrity, and neural cell death. This comprehensive analysis emphasizes the complex interplay of circadian disruption, hypertension, diabetes, and dyslipidemia in increasing stroke risk among shift workers. Understanding these mechanisms is essential for developing targeted interventions to reduce stroke susceptibility and improve cerebrovascular health in this vulnerable population. [ABSTRACT FROM AUTHOR]

Galls are thought to be induced by insects for protection, yet many gall‐forming insects experience heavy parasitization. Little is known about how parasitoids locate gall‐forming insects. Quadrastichus mendeli Kim & La Salle (Hymenoptera: Eulophidae) is an obligate ectoparasitoid of the larvae of Leptocybe invasa Fisher et La Salle (Hymenoptera: Eulophidae), which is an invasive gall‐forming pest in eucalyptus (Eucalyptus spp., Myrtaceae) plantations. In this study, Q. mendeli and L. invasa were used to explore parasitoid behavior when locating gall‐forming insects. Our results revealed that host location by Q. mendeli involved five discrete steps: walking, resting or grooming, antennating, probing and stinging. Antennation was the most frequent behavior, accounting for about half of the total time. Host location behavior of Q. mendeli occurred in the photophase. Female Q. mendeli exhibited a clear circadian rhythm: Almost all behaviors occurred during the photophase, and behavior peaked at the sixth hour of the light phase. The olfactory response rates of Q. mendeli to volatiles from galls decreased significantly after their antennae were detached. However, there was no significant difference in the host location behavior of Q. mendeli after their eyes were obscured. Our results provide essential information to explore the host location mechanisms in gall parasitoids. [ABSTRACT FROM AUTHOR]

In mammals, there is a central clock that regulates both physiological and behavioral circadian rhythms. This clock is situated within the suprachiasmatic nucleus (SCN), which consists of two nuclei in the mammalian brain. Each nucleus has two subgroups, i.e., the ventral-lateral (VL) part and the dorsal-medial (DM) part, so that a total of four subgroups are within the SCN. Thus far, the connection structures of the four subgroups has not been explored in the experiment due to the lack of technology. In this study, based on the Poincaré model, we examined the effect of the connection structures on the synchronization between the subgroups, which is important for the robust rhythms of the SCN, under constant darkness. Comparing seven structures, we found that the connection of the VL in one nucleus to the DM in another is more conducive to the synchronization, but the connection between the two VL subgroups or between the two DM subgroups across the different nuclei reduces the synchronization degree. Our findings illuminate the influence of the connection structures of the four subgroups on the SCN function. [ABSTRACT FROM AUTHOR]

Understanding the daily activity patterns and social dynamics of giraffes (Giraffa camelopardalis) is crucial for their management and conservation. In this study, a comprehensive 24-hour observational analysis of three female reticulated giraffes kept for three weeks at the Opel-Zoo in Kronberg, Germany, was conducted. Using infrared-sensitive cameras, the study captured behavioral data across baseline and two intervention phases involving changes in group composition. Social network analysis was performed using the Mantel test to assess changes in social interactions between day and night and across different study periods, while the MRQAP was applied to evaluate the influence of individual subtypes on the social structure. During the day, the giraffes exhibited a high level of activity, primarily engaging in walking, standing, and feeding behaviors. Diurnal resting was minimal, with sporadic lying phases. Night-time behavior was markedly different, with the giraffes spending most of the night lying down, interspersed with periods of feeding. The presence of a male giraffe during one intervention phase significantly altered diurnal activity patterns, increasing standing behaviors and decreasing feeding time. Social interactions, including nearest neighbor preferences, varied across day and night periods and changed with alterations in group composition. The study highlights the complexity of giraffe social dynamics and their adaptation to different social contexts. These findings provide valuable insights into the natural behavioral rhythms and social behaviors of giraffes, which are essential for effective zoo management and conservation strategies. [ABSTRACT FROM AUTHOR]

This study aimed to analyze vital sign characteristics of adult patients admitted at the Tertiary Hospital, and to define fever threshold and average body temperature by examining the tympanic temperatures of all patients. Retrospective medical data were extracted from 9195 patients aged > 21 years admitted to a tertiary hospital for elective surgeries between 2016 and 2020. Data regarding the patients' vital signs during their hospital stay, including tympanic body temperature, heart rate, and respiratory rate, were analyzed according to age, sex, and circadian rhythm. A normal-distribution graph was obtained when all the body temperature results were aligned. The average body temperature measured was 36.91 ± 0.45 °C (average ± standard deviation), indicating a potential fever threshold of 37.81 °C. When the participants were divided into age groups, the average temperature, heart rate, and respiratory rate exhibited parabolic trends. Patients in their 60s exhibited the lowest average temperature (36.88 °C), whereas those in their 50s had the lowest average heart rate (75.82/min) and lowest respiratory rate (19.08/min). Heart rate and respiratory rate tended to increase in elderly people older than 81 years. The average body temperature was greater in women than in men (36.94 ± 0.42 °C vs. 36.89 ± 0.47 °C), while the average heart (75.53 ± 10.04/min vs. 77.31 ± 11.52/min) and respiratory rates (19.13 ± 1.39/min vs. 19.29 ± 2.24/min) were lower in women than in men respectively. According to the time of measurement, the average temperature and heart rate appeared to follow a sinusoidal pattern, suggesting that the circadian rhythm was highest at 1 a.m. and lowest at 8 a.m. Tympanic temperature is a convenient measurement method preferred in hospital settings because it is noninvasive and easier to measure compared to other body parts. To develop an improved device and measurement method in the future, it is necessary to analyze tympanic temperature big data and compare it with past vital sign data or biometric information from other body parts. [ABSTRACT FROM AUTHOR]

Tumor-associated macrophages (TAMs) are prime therapeutic targets due to their pro-tumorigenic functions, but varying efficacy of macrophage-targeting therapies highlights our incomplete understanding of how macrophages are regulated within the tumor microenvironment (TME). The circadian clock is a key regulator of macrophage function, but how circadian rhythms of macrophages are influenced by the TME remains unknown. Here, we show that conditions associated with the TME such as polarizing stimuli, acidic pH, and lactate can alter circadian rhythms in macrophages. While cyclic AMP (cAMP) has been reported to play a role in macrophage response to acidic pH, our results indicate pH-driven changes in circadian rhythms are not mediated solely by cAMP signaling. Remarkably, circadian disorder of TAMs was revealed by clock correlation distance analysis. Our data suggest that heterogeneity in circadian rhythms within the TAM population level may underlie this circadian disorder. Finally, we report that circadian regulation of macrophages suppresses tumor growth in a murine model of pancreatic cancer. Our work demonstrates a novel mechanism by which the TME influences macrophage biology through modulation of circadian rhythms. Synopsis: Circadian rhythms of macrophages are altered by conditions associated with the tumor microenvironment, including acidic pH. This may be responsible for the heterogeneity in circadian clock gene expression within the tumor-associated macrophage population. Circadian rhythms of macrophages are altered by polarizing stimuli, acidic pH, and lactate. There is circadian disorder in the tumor-associated macrophage population. Heterogeneity of circadian rhythms and circadian gene expression within a population may underlie circadian disorder. The circadian clock in tumor-associated macrophages plays a tumor-suppressive role in pancreatic cancer. Circadian rhythms of macrophages are altered by conditions associated with the tumor microenvironment, including acidic pH. This may be responsible for the heterogeneity in circadian clock gene expression within the tumor-associated macrophage population. [ABSTRACT FROM AUTHOR]

Background: Resting heart rate (HR) and HR variability (HRV) are widely used parameters to assess cardiac autonomic nervous system function noninvasively. While resting assessments can be performed during sleep or after awakening, it would be relevant to know how interchangeable the results of these measurements are. This study aimed at examining the alignment between nocturnal and morning assessments during regular endurance training and in response to intensive training. A total of 24 recreational runners performed a 3-week baseline period (BL) and a 2-week overload (OL) period (Lucia's training impulse + 80%). Their running performance was assessed with a 3000-m running test after the BL and OL. The participants recorded daily their nocturnal HR and HRV (the natural logarithm of the root mean square of successive differences; LnRMSSD) with a photoplethysmography-based wrist device and performed an orthostatic test (2-min supine, 2-min standing) every morning with a chest-strap HR sensor. The HR and LnRMSSD segments that were analyzed from the nocturnal recordings included start value (SleepStart), end value (SleepEnd), first 4-h segment 30 min after detected sleep onset (Sleep4h), and full sleep time (SleepFull). The morning segments consisted of the last-minute average in both body positions. All segments were compared at BL and in response to the 3000-m test and OL. Results: All nocturnal HR and LnRMSSD segments correlated with supine and standing segments at BL (r = 0.42 to 0.91, p < 0.05). After the 3000-m test, the HR increased and LnRMSSD decreased only in the SleepStart, Sleep4h, and SleepFull segments (p < 0.05). In response to the OL, the standing HR decreased (p < 0.01), while the LnRMSSD increased (p < 0.05) in all segments except for SleepStart. The Pearson correlations between relative changes in nocturnal and morning segments were − 0.11 to 0.72 (3000-m) and − 0.25 to 0.79 (OL). The OL response in Sleep4h HR and LnRMSSD correlated with the relative change in 3000-m time (r = 0.63, p = 0.001 and r=-0.50, p = 0.013, respectively). Conclusions: Nocturnal and morning HR and LnRMSSD correlated moderately or highly in the majority of cases during the BL, but their responses to intensive training were not similarly aligned, especially in LnRMSSD. The nocturnal segments seemed to be sensitive to physical loading, and their responses were associated with the performance-related training responses. Key Points: • Moderate-to-high correlations were found between nocturnal and morning assessments of HR and HRV during regular endurance training in recreational runners. • In their responses to maximum exercise, nocturnal and morning HR and HRV were not necessarily aligned, as nocturnal segments seemed more responsive to such a stimulus. • While lower HR and higher HRV were associated with better endurance performance in all recording segments, changes in these parameters after the overload period correlated only in nocturnal segments. [ABSTRACT FROM AUTHOR]

In this paper we propose some Harris-like criteria in order to study the long time behavior of general positive and periodic semiflows. These criteria allow us to obtain new existence results of principal eigenelements, and their exponential attractiveness. We present applications to two biological models in a space-time varying environment: a non local selection-mutation equation and a growth-fragmentation equation. The particularity of this article is to study some inhomogeneous problems that are periodic in time, as it appears for instance when the environment changes, due for instance to the seasonal cycle or circadian rhythms. [ABSTRACT FROM AUTHOR]

Studies have documented various effects of circadian rhythm and daytime variations on the cardiovascular and immune system as well as wound healing. From June to December 2016, n = 367 cardiac surgery patients were enrolled. Microbiological swabs from the mediastinum and subcutaneous wound were taken before sternal closure. Patients were assigned to groups based on operation start: morning (n = 219) or afternoon (n = 135). Bacterial contamination and wound infections were studied in relation to circadian rhythm and daytime variation. We did not observe any difference in mortality (morning: 3.7%, afternoon: 3.0%, p > 0.99) and major adverse events (morning: 8.2%, afternoon: 5.9%, p = 0.53). In 27.7% of the morning group, at least one positive intraoperative swab was observed, similar to the afternoon group (25.6%, p = 0.71). The incidence of positive presternal swabs was 15.6% in the morning compared to 9.1% in the afternoon (p = 0.18). About 90% of the germs detected were part of the natural skin flora (e.g., Cutibacterium acnes and Staphylococcus epidermidis). The incidence of sternal wound infections was 7.3% (morning) and 3.0% (afternoon) (p = 0.18). We did not find differences in the incidence of intraoperative bacterial sternal contamination, nor postoperative infections, between patients who underwent cardiac surgery in the morning or afternoon. [ABSTRACT FROM AUTHOR]

ABSTRACT Migration in animals and associated adaptations to contrasting environments are underpinned by complex genetic architecture. Here, we explore the genomic basis of facultative anadromy in brown trout (Salmo trutta), wherein some individuals migrate to sea while others remain resident in natal rivers, to better understand how alternative migratory tactics (AMTs) are maintained evolutionarily. To identify genomic variants associated with AMTs, we sequenced whole genomes for 194 individual trout from five anadromous–resident population pairs, situated above and below waterfalls, in five different Irish rivers. These waterfalls act as natural barriers to upstream migration and hence we predicted that loci underpinning AMTs should be under similar divergent selection across these replicate pairs. A sliding windows based analysis revealed a highly polygenic adaptive divergence between anadromous and resident populations, encompassing 329 differentiated genomic regions. These regions were associated with 292 genes involved in various processes crucial for AMTs, including energy homeostasis, reproduction, osmoregulation, immunity, circadian rhythm and neural function. Furthermore, examining patterns of diversity we were able to link specific genes and biological processes to putative AMT trait classes: migratory‐propensity, migratory‐lifestyle and residency. Importantly, AMT outlier regions possessed higher genetic diversity than the background genome, particularly in the anadromous group, suggesting balancing selection may play a role in maintaining genetic variation. Overall, the results from this study provide important insights into the genetic architecture of migration and the evolutionary mechanisms shaping genomic diversity within and across populations. [ABSTRACT FROM AUTHOR]

Aim Methods Results Conclusion Immune dysregulation and delayed onset of sleep wake cycling (SWC) are associated with worse outcome in neonatal encephalopathy (NE), however the association between sleep and immune dysfunction in NE remains unclear. Aimed to evaluate association of sleep and systemic inflammation with outcomes in NE.Amplitude‐integrated electroencephalography (aEEG) recordings were collected on infants undergoing therapeutic hypothermia (TH). Duration to onset of (SWC) and sleep quality (SQ) were examined. Blood samples collected during the first 2 days of life. Thirteen pro‐ and anti‐inflammatory serum cytokines were quantified. Adverse outcome defined as death or abnormal MRI brain.Earlier onset of SWC and better SQ had less adverse outcomes. SQ provided better prognostic value and showed better interobserver agreement compared to duration to SWC. Better SQ associated with lower cytokines EPO and interleukin (IL)‐1β. In infants with unfavourable outcome, shorter duration to SWC was associated with higher EPO and better SQ was associated with lower TNF‐α.Earlier onset of SWC or better SQ showed less systemic inflammation and fewer adverse outcomes. SQ during TH provided better prognostic information than time of onset of SWC. Modulation of circadian rhythm in infants with NE may have an immunomodulatory role, leading to improved outcomes. [ABSTRACT FROM AUTHOR]

Background: Myopia is a growing healthcare concern worldwide. Increasing evidence suggests that sleep and circadian rhythms may be associated with myopia. Furthermore, the risk factors of myopia have not been studied in the Estonian population to date. This study aimed to evaluate chronotype, lifestyle factors, and parental myopia in relation to myopia in Estonian secondary school students. Methods: Grade 10 students from three secondary schools in Tallinn, each with distinct focuses: one science-oriented, one arts-oriented, and one sports-oriented, were invited to participate. They underwent a comprehensive ocular examination, including cycloplegic autorefraction and ocular biometry. Chronotype was evaluated with the Morningness − Eveningness Questionnaire. Participants reported parental myopia and replied to a set of questions, separately for schooldays and free days, to indicate the amount of time they spent outdoors, doing near work and intermediate distance activities. Myopia was defined as cycloplegic SER ≤ − 0.50 D. Logistic regression analysis was performed to assess the association of the studied factors with myopia. Results: A total of 123 students (57% female) participated in the study, with a mean age of 16.71 years (standard deviation 0.41). In a multivariable regression model, having two myopic parents was associated with higher odds of myopia (OR 3.78, 95% CI 1.15 − 12.42). We found no association between myopia and chronotype. Notably, time spent outdoors and doing near work or intermediate distance work did not affect the likelihood of having myopia. We observed that students attending the sports-oriented school had lower odds of myopia than those attending the science-oriented school (OR 0.12, 95% CI 0.03–0.51). Conclusion: Chronotype was not associated with myopia in our study sample. Consistent with previous reports, we identified parental myopia as a myopia risk factor. Interestingly, there was no association between myopia and time spent outdoors or near work. However, the odds of myopia varied depending on the school attended by the participants, which may reflect the educational load or lifestyle of participants in earlier childhood. [ABSTRACT FROM AUTHOR]

The determination of age‐related transcriptional changes may contribute to the understanding of health and life expectancy. The broad application of results from age cohorts may have limitations. Altering sample sizes per time point or sex, using a single mouse strain or tissue, a limited number of replicates, or omitting the middle of life can bias the surveys. To achieve higher general validity and to identify less distinctive players, bulk RNA sequencing of a mouse cohort, including seven organs of two strains from both sexes of 5 ages, was performed. Machine learning by bootstrapped variable importance and selection methodology (Boruta) was used to identify common aging features where the circadian rhythms (CiR) transcripts appear as promising age markers in an unsupervised analysis. Pathways of 11 numerically analyzed local network clusters were affected and classified into four major gene expression profiles, whereby CiR and proteostasis candidates were particularly conspicuous with partially opposing changes. In a data‐based interaction association network, the CiR‐proteostasis axis occupies an exposed central position, highlighting its relevance. The computation of 11,830 individual transcript associations provides potential superordinate contributors, such as hormones, to age‐related changes, as in CiR. In hormone‐sensitive LNCaP cells, short‐term supraphysiologic levels of the sex hormones dihydrotestosterone or estradiol increase the expression of the CiR transcript Bhlhe40 and the associated senescence regulator Cdkn2b (p15). According to these findings, the bilateral dysregulation of CiR appears as a fundamental protagonist of aging, whose transcripts could serve as a biological marker and its restoration as a therapeutic opportunity. [ABSTRACT FROM AUTHOR]

Wildlife that share habitats with humans with limited options for spatial avoidance must either tolerate frequent human encounters or concentrate their activity into those periods with the least risk of encountering people. Based on 5259 camera trap images of adult wolves from eight territories, we analyzed the extent to which diel activity patterns in a highly cultivated landscape with extensive public access (Denmark) could be explained from diel variation in darkness, human activity, and prey (deer) activity. A resource selection function that contrasted every camera observation (use) with 24 alternative hourly observations from the same day (availability), revealed that diel activity correlated with all three factors simultaneously with human activity having the strongest effect (negative), followed by darkness (positive) and deer activity (positive). A model incorporating these three effects had lower parsimony and classified use and availability observations just as well as a 'circadian' model that smoothed the use‐availability ratio as function of time of the day. Most of the selection for darkness was explained by variation in human activity, supporting the notion that nocturnality (proportion of observations registered at night vs. day at the equinox) is a proxy for temporal human avoidance. Contrary to our expectations, wolves were no more nocturnal in territories with unrestricted public access than in territories where public access was restricted to roads, possibly because wolves in all territories had few possibilities to walk more than few hundred meters without crossing roads. Overall, Danish wolf packs were 6.5 (95% CI: 4.6–9.6) times more active at night than at daylight, which make them amongst the most nocturnally active wolves reported so far. These results confirm the prediction that wolves in habitats with limited options for spatial human avoidance, invest more in temporal avoidance. [ABSTRACT FROM AUTHOR]

Psoriasis is a multifactorial, chronic, and inflammatory disease that severely impacts patients' quality of life. The disease is caused by genetic irregularities affected by epigenetic and environmental factors. Some of these factors may include seasonal changes, such as solar radiation, air pollution, and humidity, and changes in circadian rhythm, especially in the temporal and polar zones. Thus, some psoriasis patients report seasonal variability of symptoms. Through a comprehensive review, we aim to delve deeper into the intricate interplay between seasonality, environmental factors, and the genetic and epigenetic landscape of psoriasis. By elucidating these complex relationships, we strive to provide insights that may inform targeted interventions and personalized management strategies for individuals living with psoriasis. [ABSTRACT FROM AUTHOR]

A cluster of metabolic changes occur to provide energy for fetal growth and development during pregnancy. There is a burgeoning body of research highlighting the pivotal role of circadian rhythms in the pathogenesis of metabolic disorders and lipid homeostasis in mammals. Perturbations of the circadian system and lipid metabolism during gestation might be responsible for a variety of adverse reproductive outcomes comprising miscarriage, gestational diabetes mellitus, and preeclampsia. Growing studies have confirmed that resynchronizing circadian rhythms might alleviate metabolic disturbance. However, there is no clear evidence regarding the specific mechanisms by which the diurnal rhythm regulates lipid metabolism during pregnancy. In this review, we summarize previous knowledge on the strong interaction among the circadian clock, lipid metabolism, and pregnancy. Analyzing the circadian clock genes will improve our understanding of how circadian rhythms are implicated in complex lipid metabolic disorders during pregnancy. Exploring the potential of resynchronizing these circadian rhythms to disrupt abnormal lipid metabolism could also result in a breakthrough in reducing adverse pregnancy outcomes. [ABSTRACT FROM AUTHOR]

The circadian clock is an autonomous timekeeping system evolved by organisms to adapt to external changes, regulating a variety of important physiological and behavioral processes. Recent studies have shown that the sirtuin family of histone deacetylases is involved in regulating the expression of clock genes and plays an important role in maintaining the normal rhythm of clock gene expression and behavior. Moreover, sirtuins are regulated directly or indirectly by the circadian clock system. The mutual regulation between the circadian clock and sirtuins is likely involved in a variety of signal transduction and metabolism processes. In this review, we discuss the molecular mechanisms and research progress on the intertwined relationship between the circadian clock and sirtuins, mainly in mammals, highlighting sirtuins as molecular links between metabolic control and circadian rhythms and offering our perspectives on future developments in the field. [ABSTRACT FROM AUTHOR]

Simple Summary: This research explores the impact of modern lifestyle factors, such as exposure to artificial light, shift work, and dietary habits, on our body's internal clock and its association with increased body fat deposits and cancer risk. By reviewing various published studies, we aim to understand the physiological mechanisms underlying the increased risk of cancer associated with an unhealthy lifestyle. In particular, there is evidence that disruptions in the body's natural rhythms can lead to abnormal cortisol levels, which in turn may promote fat buildup and create an adipose environment favorable for cancer growth. Additionally, we explore the anticancer effects of melatonin, either directly on cancer cells or through its role in preventing the formation of an adipose microenvironment conducive to tumor development. Our findings could offer new insights into how lifestyle choices and melatonin regulation influence cancer development, helping researchers and healthcare professionals better understand and address these risks. Background: Recent research underscores a crucial connection between circadian rhythm disruption and cancer promotion, highlighting an urgent need for attention. Objectives: Explore the molecular mechanisms by which modern lifestyle factors—such as artificial light exposure, shift work, and dietary patterns—affect cortisol/melatonin regulation and cancer risk. Methods: Employing a narrative review approach, we synthesized findings from Scopus, Google Scholar, and PubMed to analyze lifestyle impacts on circadian health, focusing on cortisol and melatonin chronobiology as molecular markers. We included studies that documented quantitative changes in these markers due to modern lifestyle habits, excluding those lacking quantitative data or presenting inconclusive results. Subsequent sections focused solely on articles that quantified the effects of circadian disruption on adipogenesis and tumor microenvironment modifications. Results: This review shows how modern habits lead to molecular changes in cortisol and melatonin, creating adipose microenvironments that support cancer development. These disruptions facilitate immune evasion, chemotherapy resistance, and tumor growth, highlighting the critical roles of cortisol dysregulation and melatonin imbalance. Conclusions: Through the presented findings, we establish a causal link between circadian rhythm dysregulation and the promotion of certain cancer types. By elucidating this relationship, the study emphasizes the importance of addressing lifestyle factors that contribute to circadian misalignment, suggesting that targeted interventions could play a crucial role in mitigating cancer risk and improving overall health outcomes. [ABSTRACT FROM AUTHOR]

Regular exercise is believed to suppress cancer progression. However, the precise molecular mechanisms by which exercise prevents cancer development remain unclear. In this study, using a steatosis‐associated liver cancer mouse model, we found that regular exercise at a speed of 18 m/min for 20 min daily suppressed liver cancer development. To explore the underlying mechanisms, we examined the gene expression profiles in the livers of the exercise and non‐exercise groups. The expressions of circadian genes, such as Per1 and Cry2, were upregulated in the exercise group. As circadian rhythm disruption is known to cause various diseases, including cancer, improving circadian rhythm through exercise could contribute to cancer prevention. We further found that the expression of a series of E2F1 and c‐Myc target genes that directly affect the proliferation of cancer cells was downregulated in the exercise group. However, the expression of E2F1 and c‐Myc was transcriptionally unchanged but degraded at the post‐translational level by exercise. Cry2, which is regulated by the Skp1‐Cul1‐FBXL3 (SCFFBXL3) ubiquitin ligase complex by binding to FBXL3, can form a complex with E2F1 and c‐Myc, which we think is the mechanism to degrade them. Our study revealed a previously unknown mechanism by which exercise prevents cancer development. [ABSTRACT FROM AUTHOR]

Objective: Ultradian rhythms are biological rhythms with periods of a few seconds to a few hours. Along with circadian rhythms, ultradian rhythms influence human physiology. However, such rhythms have not been studied as intensively as circadian rhythms. This study aimed to identify ultradian rest-activity rhythms induced by the dopamine D2/D3 agonist quinpirole in mice. Methods: We used 10 mice from the Institute of Cancer Research. Quinpirole was administered at a dose of 0.5 mg/kg. We assessed free rest-activity using infrared detectors and conducted wavelet analysis to measure the period and its variation. We also used the paired t test to compare ultradian rhythm patterns. Results: Quinpirole did not significantly change total 24-hour locomotor activity ( p = 0.065). However, it significantly increased locomotor activity during the dark phase ( p = 0.001) and decreased it during the light phase ( p = 0.016). In the continuous wavelet transform analysis, the mean period was 5.618 hours before quinpirole injection and 4.523 hours after injection. The period showed a significant decrease ( p = 0.040), while the variation remained relatively consistent before and after quinpirole injection. Conclusion: This study demonstrated ultradian rest-activity rhythms induced by quinpirole using wavelet analysis. Quinpirole-induced ultradian rhythms exhibited rapid oscillations with shortened periods and increased activity during the dark phase. To better understand these changes in ultradian rhythms caused by quinpirole, it is essential to compare them with the effects of other psychopharmacological agents. Furthermore, investigating the pharmacological impact on ultradian rest-activity rhythms may have valuable applications in clinical studies. [ABSTRACT FROM AUTHOR]

Background: Diabetic Kidney Disease (DKD) is a complex disease associated with circadian rhythm and biological clock regulation disorders. Melatonin (MT) is considered a hormone with renal protective effects, but its mechanism of action in DKD is unclear. Methods: We used the GSE151325 dataset from the GEO database for differential gene analysis and further explored related genes and pathways through GO and KEGG analysis and PPI network analysis. Additionally, this study used a type 2 diabetes db/db mouse model and investigated the role of melatonin in DKD and its relationship with clock genes through immunohistochemistry, Western blot, real-time PCR, ELISA, chromatin immunoprecipitation (ChIP), dual-luciferase reporter technology, and liposome transfection technology to study DEC1 siRNA. Results: Bioinformatics analysis revealed the central position of clock genes such as CLOCK, DEC1, Bhlhe41, CRY1, and RORB in DKD. Their interaction with key inflammatory regulators may reveal melatonin's potential mechanism in treating diabetic kidney disease. Further experimental results showed that melatonin significantly improved the renal pathological changes in db/db mice, reduced body weight and blood sugar, regulated clock genes in renal tissue, and downregulated the TLR2/MyD88/NF-κB signaling pathway. We found that the transcription factor DEC1 can bind to the TLR2 promoter and activate its transcription, while CLOCK's effect is unclear. Liposome transfection experiments further confirmed the effect of DEC1 on the TLR2/MyD88/NF-κB signaling pathway. Conclusion: Melatonin shows significant renal protective effects by regulating clock genes and downregulating the TLR2/MyD88/NF-κB signaling pathway. The transcription factor DEC1 may become a key regulatory factor for renal inflammation and fibrosis by activating TLR2 promoter transcription. These findings provide new perspectives and directions for the potential application of melatonin in DKD treatment. [ABSTRACT FROM AUTHOR]

Athletes frequently compete only a few days after long‐haul travel. Longitudinal real‐world data on athletes’ sleep and sleep–wake cycle in competitive settings remain scarce. This study assessed the impact of a long‐haul travel across ∼13 time zones on sleep patterns, rest–activity circadian rhythms (RAR), and their subsequent effects on neuromuscular function and race performance in the Canadian Short‐Track Speed Skating Team. Nineteen athletes (24 ± 4 years, 11 women) travelled from Montréal (UTC‐5) to Asia (UTC+8, UTC+9) for World Cup races between 2017 and 2019. Actigraphy data were collected before (Baseline) and during travel, during the stay in Asia (SIA), and during competition days. RAR were computed using cosinor analyses on accelerometry data with 24 h phase periods. Countermovement jump height (CMJ) was measured in a subsample (n = 10). Compared to baseline (7:08 ± 0:53), athletes obtained less sleep during travel (6:16 ± 1:27) and competition days (6:35 ± 1:10), and more during SIA (7:32 ± 0:46; time effect P < 0.0001). Sleep efficiency and CMJ were greater in SIA than baseline (P = 0.007 and P = 0.0004, respectively). During SIA, sleep time increased by 9 min per night until the fifth day (P < 0.0001), with a slight decrease in sleep efficiency (P = 0.005) and an increase in CMJ (P < 0.0001). For RAR, mean activity peaked on day 2, shifting from late evening to ∼15:00. Race performance was not different from other races of the same season (P > 0.254). Our results demonstrated that, despite the possible sleep debt from the long‐haul travel, athletes recovered within 5 days, highlighting their adaptability to manage sleep debt and jetlag without impacting competitive outcomes. [ABSTRACT FROM AUTHOR]

Living organisms, which are constantly exposed to cyclical variations in their environment, need a high degree of plasticity in their visual system to respond to daily and seasonal fluctuations in lighting conditions. In Drosophila melanogaster, the visual system is a complex tissue comprising different photoreception structures that exhibit daily rhythms in gene expression, cell morphology, and synaptic plasticity, regulated by both the central and peripheral clocks. In this review, we briefly summarize the structure of the circadian clock and the visual system in Drosophila and comprehensively describe circadian oscillations in visual structures, from molecules to behaviors, which are fundamental for the fine‐tuning of visual sensitivity. We also compare some features of the rhythmicity in the visual system with that of the central pacemaker and hypothesize about the differences in the regulatory signals and mechanisms that control these two clocks. [ABSTRACT FROM AUTHOR]

The article "To Home-Routine-Sleep, or Not to Home-Routine-Sleep: That Is the Intensive Care Question" discusses the impact of sleep disruptions on critically ill children in the Pediatric Intensive Care Unit (PICU). Factors such as chaotic surroundings, pain, medications, and caregiving can disrupt circadian rhythms and inhibit melatonin production, leading to cognitive impairment. The study highlights the importance of maintaining consistent sleep routines and identifies modifiable factors like sound pollution and nutrition timing that can impact sleep quality in the PICU. While the study provides valuable insights, methodological weaknesses limit the robustness of its conclusions, emphasizing the need for further research to develop effective sleep-promoting interventions for critically ill children. [Extracted from the article]

Alzheimer's disease (AD) is a leading cause of mortality and morbidity among aging populations worldwide. Despite arduous research efforts, treatment options for this devastating neurodegenerative disease are limited. Sleep disturbances, through their link to changes in neural excitability and impaired clearance of interstitial abnormal protein aggregates, are a key risk factor for the development of AD. Research also suggests that the neuroprotective effects of sleep are particularly active during slow wave sleep. Given the strong link between sleep disturbance and AD, targeting sleep in the prodromal stages of AD, such as in mild cognitive impairment (MCI), represents a promising avenue for slowing the onset of AD-related cognitive decline. In efforts to improve sleep in older individuals, several pharmacologic approaches have been employed, but many pose safety risks, concern for worsening cognitive function, and fail to effectively target slow wave sleep. Trazodone, a safe and widely used drug in the older adult population, has shown promise in inducing slow wave sleep in older adults, but requires more rigorous research to understand its effects on sleep and cognition in the prodromal stages of AD. In this review, we present the rationale and study design for our randomized, double-bind, placebo-controlled, crossover trial (NCT05282550) investigating the effects of trazodone on sleep and cognition in 100 older adults with amnestic MCI and sleep complaints. [ABSTRACT FROM AUTHOR]

The liver has many functions including the regulation of nutrient and metabolite levels in the systemic circulation through efficient transport into and out of hepatocytes. To sustain these functions, hepatocytes display large functional heterogeneity. This heterogeneity is reflected by zonation of metabolic processes that take place in different zones of the liver lobule, where nutrient‐rich blood enters the liver in the periportal zone and flows through the mid‐zone prior to drainage by a central vein in the pericentral zone. Metabolite transport plays a pivotal role in the division of labor across liver zones, being either transport into the hepatocyte or transport between hepatocytes through the blood. Signaling pathways that regulate zonation, such as Wnt/β‐catenin, have been shown to play a causal role in the development of metabolic dysfunction‐associated steatohepatitis (MASH) progression, but the (patho)physiological regulation of metabolite transport remains enigmatic. Despite the practical challenges to separately study individual liver zones, technological advancements in the recent years have greatly improved insight in spatially divided metabolite transport. This review summarizes the theories behind the regulation of zonation, diurnal rhythms and their effect on metabolic zonation, contemporary techniques used to study zonation and current technological challenges, and discusses the current view on spatial and temporal metabolite transport. [ABSTRACT FROM AUTHOR]

During adolescence major shifts in sleep and circadian systems occur with a notable circadian phase delay. Yet, the circadian influence on pain during early adolescence is largely unknown. Using 2 years of data from the Adolescent Brain Cognitive Development study, we investigated the impact of chronotype on pain incidence, moderate-to-severe pain, and multiregion pain 1 year later in U.S. adolescents. Based on the Munich ChronoType Questionnaire, chronotype was calculated as the midpoint between sleep onset and offset on free days, corrected for sleep debt over the week. Adolescents reported pain presence over the past month, and if present, rated pain intensity (0-10 numerical rating scale; ≥ 4 defined as moderate-to-severe pain) and body site locations (Collaborative Health Outcomes Information Registry Body Map; ≥2 regions defined as multiregion pain). Three-level random intercept logistic regression models were specified for each pain outcome, adjusting for baseline sociodemographic and developmental characteristics. Among 5991 initially pain-free adolescents (mean age 12.0 years, SD 0.7), the mean chronotype was 3:59 am (SD 97 minutes), and the 1-year incidence of pain, moderate-to-severe pain, and multiregional pain was 24.4%, 15.2%, and 13.5%, respectively. Each hour later chronotype at baseline was associated with higher odds of developing any pain (odds ratio [OR] = 1.06, 95% confidence interval [CI] = 1.01, 1.11), moderate-to-severe pain (OR = 1.10, 95% CI = 1.05-1.17), and multiregion pain (OR = 1.08, 95% CI = 1.02-1.14) during 1-year follow-up. In this diverse U.S. adolescent sample, later chronotype predicted higher incidence of new-onset pain. [ABSTRACT FROM AUTHOR]

[Display omitted] • Antioxidant, clock, and neurotrophic factors oscillate in the temporal cortex (TC). • Age-related oxidative stress disrupts the circadian organization in the TC. • Arrhythmic Nrf2 expression becomes rhythmic in the TC of aged rats. • Daily average of Bdnf and Rc3 expression increases in the old TC. Disruption of circadian rhythms contributes to deficits in cognitive functions during aging. Up to date, the biochemical, molecular and chronobiological bases of such deterioration have not been completely elucidated. Here, we aim: 1) to investigate the endogenous nature of 24 h-rhythms of antioxidant defenses, oxidative stress, clocḱ's, and neurotrophic factors expression, in the rat temporal cortex (TC), and 2) to study the consequences of aging on the circadian organization of those factors. We observed a circadian organization of antioxidant enzymes activity, lipoperoxidation and the clock, BMAL1 and RORa, proteins, in the TC of young rats. Such temporal organization suggests the existence of a two-way communication among clock transcription factors and antioxidant defenses. This might generate the rhythmic and circadian expression of Bdnf and Rc3 genes involved in the TC-depending cognitive function. Noteworthy, such circadian organization disappears in the TC of aged rats. Aging also reduces glutathione peroxidase activity and expression, and it increases lipid peroxidation, throughout a 24 h-period. An increased oxidative stress makes the cellular redox environment change into an oxidative status which alters the endogenous clock activity and disrupts the circadian organization of, at least part, of the molecular basis of the synaptic plasticity in the TC. [ABSTRACT FROM AUTHOR]

Summary: Arabidopsis PSEUDORESPONSE REGULATOR7 (PRR7) is a core component of the circadian oscillator which also plays a crucial role in freezing tolerance. PRR7 undergoes proteasome‐dependent degradation to discretely phase maximal expression in early evening. While its repressive activity on downstream genes is integral to cold regulation, the mechanism of the conditional regulation of the PRR7 abundance is unknown.We used mutant analysis, protein interaction and ubiquitylation assays to establish that the ubiquitin ligase adaptor, HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE 15 (HOS15), controls the protein accumulation pattern of PRR7 through direct protein–protein interactions at low temperatures. Freezing tolerance and electrolyte leakage assays show that PRR7 enhances cold temperature sensitivity, supported by ChIP‐qPCR at C‐REPEAT BINDING FACTOR1 (CBF1) and COLD‐REGULATED 15A (COR15A) promoters where PRR7 levels were higher in hos15 mutants.HOS15 mediates PRR7 turnover through enhanced ubiquitylation at low temperature in the dark. Under the same conditions, increased PRR7 association with the promoters of CBFs and COR15A in hos15 correlates with decreased CBF1 and COR15A transcription and enhanced freezing sensitivity.We propose a novel mechanism whereby HOS15‐mediated degradation of PRR7 provides an intersection between the circadian system and other cold acclimation pathways that lead to increased freezing tolerance. [ABSTRACT FROM AUTHOR]

Lighting in unconventional environments is closely related to eye health and circadian rhythms, making it essential for warm-colour light sources to align with technological advancements in solid-state lighting. Herein, warm light in spectral region over 550 nm is realised in Sm3+ doped multicomponent borotellurite (MBT-Sm) glass phosphors as colour converters for LEDs/LDs and their luminescent behaviours are quantified in detail. MBT-Sm glass phosphors standout for their high transparency and the large absorption/emission cross-section, with high quantum efficiency of 84.1 % and quantum yield of 19.15 % under violet LED excitation, and a high luminous flux of 3.33 lm under 50 mW laser. Remarkably, it not only possesses superior colour performance with the correlated colour temperature below 2000 K and colour purity up to 99.8 %, but also shows excellent heat resistance of luminescence. MBT-Sm glass phosphors show promising applications as colour conversion materials in innovative lighting technology. [ABSTRACT FROM AUTHOR]

The circadian clock system, an evolutionarily conserved mechanism, orchestrates diurnal rhythms in biological activities such as behavior and metabolism, aligning them with the earth's 24-hour light/dark cycle. This synchronization enables organisms to anticipate and adapt to predictable environmental changes, including nutrient availability. However, modern lifestyles characterized by irregular eating and sleeping habits disrupt this synchrony, leading to metabolic disorders such as obesity and metabolic syndrome, evidenced by higher obesity rates among shift workers. Conversely, circadian disturbances are also associated with reduced nutrient absorption and an increased risk of malnutrition in populations such as the critically ill or the elderly. The precise mechanisms of these disturbances in leading to either overnutrition or undernutrition is complex and not yet fully understood. Glucose, a crucial energy source, is closely linked to obesity when consumed excessively and to weight loss when intake is reduced, which suggests that circadian regulation of glucose metabolism is a key factor connecting circadian disturbances with nutritional outcomes. In this review, we describe how the biological clock in various tissues regulates glucose metabolism, with a primary focus on studies utilizing animal models. Additionally, we highlight current clinical evidence supporting the association between circadian disturbance and glucose metabolism, arguing that such disruption could predominantly contribute to undernutrition due to impaired efficient utilization of nutrients. [ABSTRACT FROM AUTHOR]

Acidic stress is a formidable environmental factor that exerts adverse effects on plant growth and development, ultimately leading to a potential reduction in agricultural productivity. A low pH triggers Ca2+ influx across the plasma membrane (PM), eliciting distinct responses under various acidic pH levels. However, the underlying mechanisms by which Arabidopsis plant cells generate stimulus-specific Ca2+ signals in response to acidic stress remain largely unexplored. The experimentally induced stimulus may elicit spikes in cytosolic free Ca2+ concentration ([Ca2+]i) spikes or complex [Ca2+]i oscillations that persist for 20 min over a long-term of 24 h or even several days within the plant cytosol and chloroplast. This study investigated the increase in [Ca2+]i under a gradient of low pH stress ranging from pH 3.0 to 6.0. Notably, the peak of [Ca2+]i elevation was lower at pH 4.0 than at pH 3.0 during the initial 8 h, while other pH levels did not significantly increase [Ca2+]i compared to low acidic stress conditions. Lanthanum chloride (LaCl3) can effectively suppress the influx of [Ca2+]i from the apoplastic to the cytoplasm in plants under acid stress, with no discernible difference in intracellular calcium levels observed in Arabidopsis. Following 8 h of acid treatment in the darkness, the intracellular baseline Ca2+ levels in Arabidopsis were significantly elevated when exposed to low pH stress. A moderately low pH, specifically 4.0, may function as a spatial-temporal input into the circadian clock system. These findings suggest that acid stimulation can exert a continuous influence on intracellular calcium levels, as well as plant growth and development. [ABSTRACT FROM AUTHOR]

Heat stress (HS) exerts detrimental effects on animal production, with lactating sows being particularly vulnerable. Understanding the mechanisms involved in HS response could aid in developing effective strategies against the negative impacts on livestock. Recent genome wide association studies identified two core circadian clock genes as potential candidates in mediating HS response. The study aimed to investigate how cooling lactating sows under natural heat stress conditions impacted circadian patterns of respiration rate (RR), rectal temperature (RT), behavior, salivary melatonin and cortisol levels, and diurnal patterns of cytokines in saliva. Mixed parity lactating sows were assigned to one of two treatment groups: electronic cooling pad (C; n = 9) and heat-stressed (H; n = 9). The experiment spanned two 48 h periods of elevated ambient temperatures due to summer heat wave. In the first 48 h period, RR was recorded every 30 min, RT every 60 min, and behaviors (eating, standing, sitting, laying, sleeping, drinking, and nursing) every 5 min. In the second 48 h period, saliva samples were collected every 4 h. Cooling reduced RR and RT and altered circadian patterns (P < 0.05). Cooling did not affect amount of time engaged in any behavior over the 48 h period (P > 0.05), however, daily patterns of eating, standing and laying differed between the treatments (P < 0.05), with altered eating behavior related to RT increment in H sows (P < 0.05). Cooling increased and altered the circadian pattern of salivary melatonin (P < 0.05). Cooling also influenced the diurnal pattern of saliva cytokines. Cooling had no impact on saliva cortisol levels. In conclusion, cooling HS sows impacted circadian rhythms of physiology and behavior, supporting the need for further research to understand if circadian disruption underlies decreased production efficiency of HS animals. [ABSTRACT FROM AUTHOR]

Background: Circadian rhythm disruption is typical in Parkinson’s disease (PD) early stage, and it plays an important role in the prognosis of the treatment effect in the advanced stage of PD. There is growing evidence that circadian rhythm genes can influence development of PD. Therefore, this study explored specific regulatory mechanism of circadian genes (C-genes) in PD through bioinformatic approaches. Methods: Differentially expressed genes (DEGs) between PD and control samples were identified from GSE22491 using differential expression analysis. The key model showing the highest correlation with PD was derived through WGCNA analysis. Then, DEGs, 1,288 C-genes and genes in key module were overlapped for yielding differentially expressed C-genes (DECGs), and they were analyzed for LASSO and SVM-RFE for yielding critical genes. Meanwhile, from GSE22491 and GSE100054, receiver operating characteristic (ROC) was implemented on critical genes to identify biomarkers, and Gene Set Enrichment Analysis (GSEA) was applied for the purpose of exploring pathways involved in biomarkers. Eventually, immune infiltrative analysis was applied for understanding effect of biomarkers on immune microenvironment, and therapeutic drugs which could affect biomarkers expressions were also predicted. Finally, we verified the expression of the genes by q-PCR. Results: Totally 634 DEGs were yielded between PD and control samples, and MEgreen module had the highest correlation with PD, thus it was defined as key model. Four critical genes (AK3, RTN3, CYP4F2, and LEPR) were identified after performing LASSO and SVM-RFE on 18 DECGs. Through ROC analysis, AK3, RTN3, and LEPR were identified as biomarkers due to their excellent ability to distinguish PD from control samples. Besides, biomarkers were associated with Parkinson’s disease and other functional pathways. Conclusion: Through bioinformatic analysis, the circadian rhythm related biomarkers were identified (AK3, RTN3 and LEPR) in PD, contributing to studies related to PD treatment. [ABSTRACT FROM AUTHOR]

The human body's physiological and behavioral activities are largely regulated by circadian rhythms. Chronotype predispose individuals to health problems. This paper emphasizes the importance of integrating chronotype assessments into studies on circadian rhythm and health. Precise risk assessments could result from this approach, especially in Asia and northern latitudes. [ABSTRACT FROM AUTHOR]

Phytochrome-interacting factors (PIFs) are a subgroup of transcription factors within the basic helix-loop-helix (bHLH) family, playing a crucial role in integrating various environmental signals to regulate plant growth and development. Despite the significance of PIFs in these processes, a comprehensive genome-wide analysis of PIFs in conifers has yet to be conducted. In this investigation, three PtPIF genes were identified in Chinese pine, categorized into three subgroups, with conserved motifs indicating the presence of the APA/APB motif and bHLH domain in the PtPIF1 and PtPIF3 proteins. Phylogenetic analysis revealed that the PtPIF1 and PtPIF3 proteins belong to the PIF7/8 and PIF3 groups, respectively, and were relatively conserved among gymnosperms. Additionally, a class of PIF lacking APA/APB motif was identified in conifers, suggesting its function may differ from that of traditional PIFs. The cis-elements of the PtPIF genes were systematically examined, and analysis of PtPIF gene expression across various tissues and under different light, temperature, and plant hormone conditions demonstrated similar expression profiles for PtPIF1 and PtPIF3. Investigations into protein-protein interactions and co-expression networks speculated the involvement of PtPIFs and PtPHYA/Bs in circadian rhythms and hormone signal transduction. Further analysis of transcriptome data and experimental validation indicated an interaction between PtPIF3 and PtPHYB1, potentially linked to diurnal rhythms. Notably, the study revealed that PtPIF3 may be involved in gibberellic acid (GA) signaling through its interaction with PtDELLAs, suggesting a potential role for PtPIF3 in mediating both light and GA responses. Overall, this research provides a foundation for future studies investigating the functions of PIFs in conifer growth and development. [ABSTRACT FROM AUTHOR]

Objective: Flow cytometry (FC) is probably the most important technique for single-cell analysis. It's precisely, rapid, and suitable for multidimensional single-cell analysis. The commonly used side scatter (SSC) intensity determined by FC is often interpreted as a measure of the internal cellular complexity of cells. In simple terms, the more structured a cell is, the higher the SSC intensity quantified by FC. Nevertheless, most of the studies that support this interpretation are based on data derived from animal or human cell lines and while it is assumed that the results can also be transferred to plant or algal cell lines, the details remain unclear. The objective of the recent work is to clarify the interpretation of the SSC signal from algal cells. Results: Algal lipid droplets and their starch play an inherent role to shape the popular SSC signal derived from FC. This was shown by a theoretical approach based on Lorenz–Mie theory. These results were supported by experiments with different model cultures of Chlamydomonas reinhardtii in which a high linear correlation was observed between the SSC signal and the 'physical' starch quantity. [ABSTRACT FROM AUTHOR]