Search Results (184)

The use of multimodal data can effectively compensate for the lack of temporal resolution in streetscape imagery-based studies and achieve hourly refinement in the study of street walkability dynamics. Exploring the 24 h dynamic pattern of urban street walkability and its diurnal variation characteristics is a crucial step in understanding and responding to the accelerated urban metabolism. Aiming at the shortcomings of existing studies, which are mostly limited to static assessment or only at coarse time scales, this study integrates multimodal data such as streetscape images, remote sensing images of nighttime lights, and text-described crowd activity information and introduces a novel approach to enhance the simulation of pedestrian perception through a visual–textual multimodal deep learning model. A baseline model for dynamic assessment of walkability with street as a spatial unit and hour as a time granularity is generated. In order to deeply explore the dynamic regulation mechanism of street walkability under the influence of diurnal shift, the 24 h dynamic score of walkability is calculated, and the quantification system of walkability diurnal change characteristics is further proposed. The results of spatio-temporal cluster analysis and quantitative calculations show that the intensity of economic activities and pedestrian experience significantly shape the diurnal pattern of walkability, e.g., urban high-energy areas (e.g., along the riverside) show unique nocturnal activity characteristics and abnormal recovery speeds during the dawn transition. This study fills the gap in the study of hourly street dynamics at the micro-scale, and its multimodal assessment framework and dynamic quantitative index system provide important references for future urban spatial dynamics planning. Full article

This study examines diurnal surface temperature dynamics across major Moroccan cities during the growing season and explores the interaction between urban and vegetated surfaces. We also introduce the Urban Thermal Impact Ratio (UTIR), a novel metric designed to quantify urban thermal comfort as a function of the surface urban heat island (SUHI) intensity. The analysis is based on outputs from a land surface model (LSM) for the year 2010, integrating high-resolution Landsat and MODIS data to characterize land cover and biophysical parameters across twelve land cover types. Our findings reveal moderate urban–vegetation temperature differences in coastal cities like Tangier (1.8 °C) and Rabat (1.0 °C), where winter vegetation remains active. In inland areas, urban morphology plays a more dominant role: Fes, with a 20% impervious surface area (ISA), exhibits a smaller SUHI than Meknes (5% ISA), due to higher urban heating in the latter. The Atlantic desert city of Dakhla shows a distinct pattern, with a nighttime SUHI of 2.1 °C and a daytime urban cooling of −0.7 °C, driven by irrigated parks and lawns enhancing evapotranspiration and shading. At the regional scale, summer UTIR values remain below one in Tangier-Tetouan-Al Hoceima, Rabat-Sale-Kenitra, and Casablanca-Settat, suggesting that urban conditions generally stay within thermal comfort thresholds. In contrast, higher UTIR values in Marrakech-Safi, Beni Mellal-Khénifra, and Guelmim-Oued Noun indicate elevated heat discomfort. At the city scale, the UTIR in Tangier, Rabat, and Casablanca demonstrates a clear diurnal pattern: it emerges around 11:00 a.m., peaks at 1:00 p.m., and fades by 3:00 p.m. This study highlights the critical role of vegetation in regulating urban surface temperatures and modulating urban–rural thermal contrasts. The UTIR provides a practical, scalable indicator of urban heat stress, particularly valuable in data-scarce settings. These findings carry significant implications for climate-resilient urban planning, optimized energy use, and the design of public health early warning systems in the context of climate change. Full article

Light is a major environmental factor that regulates circadian rhythms and pineal melatonin synthesis. While the influence of nighttime light exposure on melatonin suppression has been extensively investigated, much less is known about the impact of photophase light wavelength on pineal function. The aim of the study was to determine the influence of monochromatic light during the photophase on diurnal changes in melatonin-related indoles in the rat pineal gland. Wistar rats were exposed for 7 days to 150 lx of monochromatic blue (463 ± 10 nm), green (523 ± 10 nm), or red (623 ± 10 nm) LED light, or to white fluorescent light (control), under a 12:12 light–dark cycle. Pineal glands were collected every 3 h over 24 h, and the indole content was analyzed by high-performance liquid chromatography. The results demonstrated that both the timing and course of N-acetylserotonin (NAS) and melatonin (MLT) rhythms were significantly affected by light wavelength. Blue light most effectively preserved the normal rhythmicity observed under full-spectrum white light, whereas green—and particularly red light—delayed nocturnal NAS and MLT synthesis. These changes were accompanied by concurrent alternations in rhythms of serotonin, its precursors, and metabolites. The data strongly suggest that spectral light composition during the photophase influences pineal indole metabolism via melanopsin-mediated phototransduction and possibly other retinal mechanisms. These findings may have implications for the design of artificial lighting environments in human life and animal housing. Full article

Hemerocallis spp. exhibit distinct flower opening times, categorized into nocturnal and diurnal types. Previous studies have demonstrated that the circadian clock and CONSTANS (CO) genes play crucial roles in regulating flowering in Hemerocallis. However, the key genes that integrate flowering pathways remain largely unknown. To address this gap, we identified potential homologs of the FLOWERING LOCUS T (FT) gene in Hemerocallis. A yeast one-hybrid assay revealed that HfCOL2 and HfLHY directly bind to the HfFT1 and HfFT2 promoters, thereby activating FT transcription. The expression analysis reveals that HfCOL2 expression rhythms not only display opposing patterns between nocturnal and diurnal opening types of Hemerocallis but also between leaf and flower tissues. The peak expression of HfCOL2 in flowers aligns closely with the respective opening times of diurnally and nocturnally flowering Hemerocallis. The overexpression of HfCOL2 in tobacco plants led to early flowering and prolonged flower longevity. In Hemerocallis, the HfCOL2 gene plays a pivotal role not only in photoperiod-induced flowering but also in the circadian rhythm-mediated regulation of flower opening time. Due to the limited availability of plant materials exhibiting distinct flower opening rhythms, research in this area has been constrained. Identifying the key genes in the flowering pathway of Hemerocallis can facilitate a better understanding of the mechanisms by which plants respond to circadian rhythms. Full article

Background: In systemic sclerosis (SSc), endothelial dysfunction, inflammation, and reduced nitric oxide levels may disrupt circadian blood pressure (BP) regulation. There are studies showing that inflammatory and certain other cells in diseases like SSc exhibit diurnal rhythms. In our study, we examined the effect of SSc on BP. In particular, the frequency of the non-dipper pattern (lack of nighttime BP reduction) in SSc patients has not been adequately investigated. The aim of this study was to evaluate the 24 h BP profile in SSc patients and to compare the frequency of the non-dipper pattern with that of the non-scleroderma group. Additionally, the identification of disrupted circadian BP patterns in SSc patients aims to contribute to the development of personalized, time-sensitive BP monitoring strategies in the future and to support the applicability of personalized medicine in this context. Methods: A total of 31 SSc patients diagnosed according to the 2013 ACR/EULAR classification criteria and 30 age- and sex-matched individuals without SSc were included in this prospective study. BP changes between day and night were evaluated by measuring BP every 30 min with a 24 h ambulatory blood pressure monitoring (ABPM) device. The non-dipper pattern was defined as a decrease in BP of less than 10% during the night compared to the day. To better assess BP fluctuations during the night, nighttime measurements were divided into two time periods: first, 24:00–04:00, and then 04:00–08:00. Additionally, laboratory and clinical parameters and SSc subtypes were compared between the groups. Results: The ABPM findings were compared between the groups with and without SSc. The non-dipper pattern was significantly more common in the SSc group at all time intervals. The non-dipper pattern was observed in 25.8% of the non-SSc group and 83.9% of SSc patients (p < 0.001). In the period between 24:00 and 04:00, the prevalence was 25.8% in the control group and 71.0% in SSc patients (p < 0.001), and between 04:00 and 08:00, it was 35.5% in the control group and 80.6% in SSc patients (p < 0.001). No significant difference was found in non-dipper patterns between individuals with diffuse and limited cutaneous forms of systemic sclerosis. Conclusions: The non-dipper BP pattern is significantly more common in patients with SSc, indicating the disruption of the circadian rhythm affecting BP. Analysis performed by dividing the night into specific time periods revealed that this deterioration continued throughout the night. The findings highlight the importance of circadian BP monitoring in SSc patients and may contribute to future risk stratification and treatment strategies. Circadian BP analysis in SSc may help to develop strategies that are personalized for these patients and tailored to their physiological rhythm. Full article

Background: Renal ischemia–reperfusion injury (IRI) is a frequent cause of kidney transplant failure. Recent studies have shown that the extent of injury is closely linked to ferroptosis, and the process of cellular ferroptosis is diurnal and regulated by circadian genes. NRF2, involved in iron–heme metabolism, may be related to ferroptosis. We hypothesize that the pathway plays a role in circadian regulation in ferroptosis in renal IRI. Methods: Using hematoxylin and eosin (H&E) staining, enzyme-linked immunosorbent assay (ELISA), Cell Counting Kit-8 (CCK8), flow cytometry, real-time quantitative reverse transcription PCR (qRT-PCR), and Western blotting, we analyzed renal tubular tissues in vivo and in vitro and compared the groups with IR injury treatment, inhibition of ferroptosis, and inhibition of BMAL1 gene expression at the ZT0 (zeitgeber time 0) and ZT12 (zeitgeber time 12) time points. Results: IR injury treatments caused exacerbation of injury, both in vivo and in vitro, and were more pronounced at the ZT12 time point, which correlates with circadian rhythms. The use of the ferroptosis inhibitor (Fer-I) attenuated IR injury, suggesting that IRI is associated with ferroptosis. In contrast, reduced BMAL1-gene expression exacerbated injury, and NRF2, which is elevated in IR injury, was suppressed. Conclusions: The circadian gene BMAL1 affects the circadian rhythm of ferroptosis in renal IRI through the regulation of NRF2 and its downstream pathway. In this study, renal injury is well ameliorated by the ferroptosis inhibitor, exhibiting potential as a therapeutic agent for use in renal transplantation. Full article

Normal circadian rhythms are essential for organisms to adapt to diurnal changes and maintain an optimal state of physiological function. Disturbances in circadian rhythms such as shift work and working at night increase the risk of cardiovascular disease. Myocardial infarction exhibits a marked circadian rhythm, usually peaking in the early morning. Krüppel-like factor 15 (KLF15), a transcription factor with a circadian rhythm, plays an important role in cardiac physiopathology. It has a protective effect against myocardial injury after myocardial infarction by regulating energy metabolism and inflammatory factors, among other pathways. Currently, the association between circadian rhythm, KLF15, and myocardial infarction is unclear, thus this paper reviews how circadian rhythm influences the role of KLF15 in myocardial infarction, aiming to reveal the association between circadian rhythm, KLF15, and myocardial infarction, and to explore the underlying mechanisms, to provide new theoretical insights and therapeutic strategies for the clinical treatment of myocardial infarction. Full article

A detailed characterization of evapotranspiration (ET) patterns is of paramount importance for optimizing irrigation scheduling and enhancing water-use efficiency in the North China Plain. To delve into this, a two-season study was conducted at the National Experimental Station for Precise Agriculture in Beijing. Using 12 weighing lysimeters, the study compared two summer maize varieties with contrasting canopy sizes: Jingke 968 (JK), characterized by a large canopy, and CF 1002 (CF), with a small canopy. The comprehensive analysis yielded the following significant findings: (1) The daily average ET rates exhibited consistent trends across cultivars, yet with notable disparities in magnitude. JK consistently demonstrated higher water consumption throughout the growth seasons. In the first season, at the V13–R1 stage, the peak daily ET of JK and CF reached 5.91 mm/day and 5.52 mm/day, respectively. In the second season, during the R1–R3 stage, these values were 5.21 mm/day for JK and 5.22 mm/day for CF, highlighting the nuanced differences in water use between the varieties under varying growth conditions. (2) Regardless of canopy size, the hourly ET fluctuations across different growth stages followed similar temporal patterns. However, the most striking inter-varietal differences in ET emerged during the R1–R3 reproductive stages, when both cultivars had achieved peak canopy development (leaf area index, LAI > 4.5). Notably, the ET differences between JK and CF adhered to a characteristic diurnal “increase–decrease” pattern. These differences peaked during mid-morning (09:00–11:00) and early afternoon (13:00–15:00), while minimal divergence was observed at solar noon. This pattern suggests complex interactions between canopy structure, microclimate, and plant physiological processes that govern water loss over the course of a day. (3) Analysis of the pooled data pinpointed two critical time periods that significantly contributed to the cumulative ET differences between the varieties. The first period was from 12:00–17:00 during the R1–R3 (anthesis) stage, and the second was from 08:00–16:00 during the R3–R5 (grain filling) stage. JK maintained significantly higher transpiration rates (Tr) compared to CF, especially during the morning hours (09:00–12:00). On average, the Tr of JK exceeded that of CF by 5.3% during the pre-anthesis stage and by 16.0% during the post-anthesis stage. These observed Tr differentials strongly indicate that canopy architecture plays a pivotal role in modulating stomatal regulation patterns. Maize varieties with large canopies, such as JK, demonstrated enhanced morning photosynthetic activity, which likely contributed to increased transpiration. At the same time, both varieties seemed to employ similar midday water conservation strategies, possibly as an adaptive response to environmental stress. In summary, this study has comprehensively elucidated the intricate relationship between the leaf area index and the evapotranspiration of summer maize across multiple timescales, encompassing periodic, daily, and hourly variations. The findings provide invaluable data-driven insights that can underpin the development of precise and quantitative irrigation strategies, ultimately promoting sustainable and efficient maize production in the North China Plain. Full article

This study examines the climate adaptability of traditional Hani ‘Mushroom Houses’ located in the rice terrace region of Honghe Hani Autonomous Prefecture, Yunnan, China. By analyzing 30 years of meteorological data, the study identifies the local climatic characteristics of high temperatures, high humidity, and significant diurnal temperature variations. The thermal comfort voting method was used to establish a quantitative relationship between the Physiological Equivalent Temperature (PET) index and residents’ subjective thermal perceptions, thereby assessing seasonal variations in thermal comfort. Field measurements of indoor and outdoor temperature, humidity, and wind speed were conducted in May and December 2023 to evaluate thermal interactions between rooms. This study demonstrated: (1) the critical roles of building orientation (e.g., northwest-facing design), functional layout (e.g., multi-story zoning), and structural forms (e.g., thick walls, thatched roofs) in regulating temperature and humidity. (2) Confirmed that Hani ‘Mushroom Houses’ stabilize indoor environments through passive strategies, including material selection (wood, rammed earth), natural ventilation (cross-draft design), and spatial organization (climate-buffering storage layers). (3) Provided empirical evidence for optimizing traditional dwellings (e.g., enhanced insulation, ventilation improvements) and advancing sustainable practices in similar climatic regions. Full article

In mammals, the core molecular clock genes and the overall circadian system are established during early development; during this critical period of development, maternal metabolic condition plays a major role in programming temporal metabolic regulation. Therefore, this study aimed to evaluate the effects of the chronic maternal intake of a high-fat and high-carbohydrate diet (HFCD) before and during pregnancy, in addition to a challenge with HFCD during adulthood, on offspring diurnal metabolic profile and on clock gene expression in central and peripheral circadian oscillators. The HFCD offspring and/or those exposed to the metabolic challenge exhibited alterations in the temporal profiles of analytes associated with both the carbohydrate and lipid metabolisms, as well as markers associated with liver and kidney damage, ranging from phase changes in rhythmicity or, in some cases, to the complete loss of 24 h variations. At the molecular level, the expression of clock genes (Per1, Cry1, Bmal1, and Clock) in the central and peripheral oscillators showed differential susceptibility to undergoing changes in their abundance. Our data indicate that maternal HFCD during pregnancy, a second exposure in adulthood, or both result in the long-term misalignment of the diurnal rhythm’s metabolic and damage markers; these changes are possibly associated with alterations in the core molecular circadian clockwork. Full article

CO₂ is the primary contributor to global warming, and also the most significant anthropogenic emission gas in cities. This study investigates near-surface CO₂ spatiotemporal variability patterns at the community scale to address the critical gap in urban CO₂ high-resolution measurement and promote urban carbon neutrality. Combining fixed and mobile monitoring across five representative communities (1-km² coverage) with two-hour temporal precision and 20 m spatial resolution, results revealed average CO₂ concentrations of 440–480 ppm, exhibiting bimodal diurnal cycles and highlighting spatiotemporal divergent emission behaviors. Three communities peaked during 17:00–19:00 LT, while two peaked during 08:00–10:00 LT. Spatial correlation analysis identified two dominant patterns: road-adjacent “externally dominated” hotspots and “internally dominated” zones with elevated intra-community levels. Spearman correlation analysis, Random Forest, and Geographically and Temporally Weighted Regression models quantified spatial morphology and element contributions, demonstrating that building morphology exerted time-varying impacts across communities. Meanwhile, external traffic contributed 18–39% to concentration variability, while internal traffic and energy consumption drove localized peaks. The findings indicated that apart from the emission sources, the micro-scale urban spatial design elements also regulate the near-surface CO₂ distribution. This high-resolution approach provides actionable insights for optimizing community layouts and infrastructure to mitigate localized emissions, advancing carbon neutrality targeted urban planning. Full article

This narrative review explores the intricate relationship between circadian regulation and exercise performance, emphasizing the importance of aligning training strategies with the body’s natural physiological fluctuations. The three key mechanisms investigated are temperature, hormonal fluctuations, and diurnal chronotype—an individuals’ exhibition of enhanced physical or cognitive performance at specific times of day. Core body temperature variations impact exercise performance, suggesting strategic workout timing and intensity adjustments. Hormonal patterns (i.e., insulin, cortisol, testosterone) influence energy metabolism and muscle growth, informing tailored training plans. Diurnal chronotypes significantly affect performance, advocating for personalized training sessions based on individual preferences and entrained awakening. Integrating circadian mechanisms into training offers strategic advantages, guiding practitioners to design effective, personalized regimens, though we acknowledge relevant challenges and the need for further research. Full article

In response to the demands of climate change and urban sustainability, urban green space construction in China has rapidly expanded, while simultaneously giving rise to allergenic pollen pollution. Focusing on the central urban area of Xi’an, Shaanxi Province, China, this study utilizes urban surveys, field measurements, and pollen particle microscopy to analyze the seasonal variation in allergenic pollen pollution concentrations and the physical dispersion characteristics of allergenic pollen particles in residential areas. The study also examines the impact of urban residential area spatial layout on regulating allergenic pollen pollution. The results show that (1) allergenic pollen pollution in Xi’an’s residential areas exhibits significant seasonal characteristics, with spring, summer, and autumn being the primary seasons. The highest concentrations occur in spring, dominated by tree pollen, followed by summer and autumn with a predominance of herbaceous pollen. (2) Pollution concentrations in residential areas are affected by the diurnal temperature variation, with higher concentrations observed in public green spaces compared to residential green spaces and roadside green spaces. (3) Allergenic pollen pollution shows a layered characteristic in the vertical direction, with concentrations concentrated around 13 m above ground due to the effects of diurnal temperature variation and local microclimate. (4) Urban pollen pollution concentrations are positively correlated with high temperatures and negatively correlated with high humidity, while local circulations influence pollen dispersion concentrations in residential areas. (5) Design indicators such as plot ratio and building stagger affect the dispersion concentrations of allergenic pollen pollution in residential areas. The findings provide a scientific basis for optimizing residential area spatial design to mitigate allergenic pollen pollution and offer strategic guidance for improving the health and livability of urban environments. Full article

Background/Objectives: Parkinson’s disease (PD) and hypertension are often coexistent conditions that interact in entwined ways at various levels. Cardiovascular autonomic dysfunction (CAD), a non-motor feature of PD occurring across all stages, alters blood pressure (BP) regulation. Methods: We conducted a cross-sectional study enrolling patients with PD and primary hypertension, without diabetes mellitus or other causes of secondary CAD, aiming to characterize BP profiles/patterns by ambulatory BP monitoring. We also sought associations between different CAD phenotypes and PD characteristics, disability, and cardiovascular comorbidities. Results: We included 47 patients with a median age of 71 years, PD duration of 9 years, and Movement Disorder Society-sponsored revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part III score of 40. Diurnal and nocturnal BP values were within the reference range, but BP load was excessive. Almost one-third had neurogenic orthostatic hypotension (OH) and 80% were non-dippers. The overall burden of non-motor symptoms was significant in these phenotypes. Patients with neurogenic OH were more prone to constipation, anxiety, and urinary problems, whereas gustatory dysfunction, loss of libido, and erectile dysfunction were more frequently reported by non-dippers. No significant differences with regard to cognitive decline were identified in subjects with and without neurogenic OH. Neurogenic OH was symptomatic in 78% of the cases, whereas 56% of those with orthostatic symptoms did not have OH at repeated measurements. Conclusions: Neurogenic OH is an independent predictor of disability in patients with PD and hypertension, after adjusting for PD duration, Hoehn and Yahr stage, levodopa equivalent daily dose (LEDD), and Montreal Cognitive Assessment (MoCA) score. Full article

Measurements of concentrations of nitrogen oxides (NO_x) were collected over a period of thirteen years (2011–2023). The data were collected at Giordan Lighthouse atmospheric monitoring and research station on the Island of Gozo, forming part of the Maltese Archipelago, in the Central Mediterranean. Trend analysis shows that NO_x concentrations are decreasing at an annual rate of 0.15 ppbv per year. This is in comparison to what has been recorded across Europe due to stricter regulations and improvements in vehicle technologies. Significant reductions were observed during the COVID-19 pandemic due to the implementation of lockdowns and restrictions on mobility. NO_x concentrations also exhibit an amplitude seasonal variability of 35% with a maximum in October and a minimum in December, while the nitric oxide (NO) component of NO_x presents a broad maximum in May/June and a minimum in February. NO_x concentrations also show a strong diurnal variability with a maximum in the morning and a minimum in the afternoon. The diurnal amplitude of NO_x and NO is 44% and 148%, respectively. With respect to wind direction, the NO_x concentrations exhibit a maximum when the prevailing wind is from the South-East sector and a minimum when the wind is blowing from the West sector. Full article