Light Cycle Research Articles

Thermal management of honeycomb heat sink filled with phase change material for smart lighting applications

Recently, thermal management of LEDs lamps has become increasingly essential due to the widespread integration of LEDs in smart lighting applications. In this work, we focus on the thermal analysis of convective heat transfer using a honeycomb heat sink designed for LEDs lamp cooling. Three different heat sink geometries were examined: an aluminum-filled honeycomb radiator, a hollow honeycomb radiator, and a hollow honeycomb radiator incorporating a phase change material (PCM) layer. The results obtained from numerical simulations using COMSOL Multiphysics® showed that the third heat sink geometry, when employed in short-duration lighting applications, led to a 25% reduction in temperature for a 20W power lamp. We also determined the optimal operational time, during which the temperature drop is maximum. Moreover, we observed that the integration of a PCM-filled honeycomb radiator in cyclic lighting applications (involving on/off cycles and high/low power settings) significantly mitigates temperature rise in the lamp by leveraging the PCM's heat storage capacity. This approach effectively prevents thermal shocks, ensures prolonged LEDs performance, and contributes to energy savings in the lighting sector. By addressing the thermal management challenges associated with LEDs lamps through innovative heat sink designs and the utilization of PCM, our research offers valuable insights for enhancing the overall performance and efficiency of LED lighting systems.

Principles of synaptic encoding of brainstem circadian rhythms.

Circadian regulation of autonomic tone and reflex pathways pairs physiological processes with the daily light cycle. However, the underlying mechanisms mediating these changes on autonomic neurocircuitry are only beginning to be understood. The brainstem nucleus of the solitary tract (NTS) and adjacent nuclei, including the area postrema and dorsal motor nucleus of the vagus, are key candidates for rhythmic control of some aspects of the autonomic nervous system. Recent findings have contributed to a working model of circadian regulation in the brainstem which manifests from the transcriptional, to synaptic, to circuit levels of organization. Vagal afferent neurons and the NTS possess rhythmic clock gene expression, rhythmic action potential firing, and our recent findings demonstrate rhythmic spontaneous glutamate release. In addition, postsynaptic conductances also vary across the day producing subtle changes in membrane depolarization which govern synaptic efficacy. Together these coordinated pre- and postsynaptic changes provide nuanced control of synaptic transmission across the day to tune the sensitivity of primary afferent input and likely govern reflex output. Further, given the important role for the brainstem in integrating cues such as feeding, cardiovascular function and temperature, it may also be an underappreciated locus in mediating the effects of such non-photic entraining cues. This short review focuses on the neurophysiological principles that govern NTS synaptic transmission and how circadian rhythms impacted them across the day.

Prostaglandin F2α Affects the Cycle of Clock Gene Expression and Mouse Behavior.

Prostaglandins are bioactive compounds, and the activation of their receptors affects the expression of clock genes. However, the prostaglandin F receptor (Ptgfr) has no known relationship with biological rhythms. Here, we first measured the locomotor period lengths of Ptgfr-KO (B6.129-Ptgfrtm1Sna) mice and found that they were longer under constant dark conditions (DD) than those of wild-type (C57BL/6J) mice. We then investigated the clock gene patterns within the suprachiasmatic nucleus in Ptgfr-KO mice under DD and observed a decrease in the expression of the clock gene cryptochrome 1 (Cry1), which is related to the circadian cycle. Moreover, the expression of Cry1, Cry2, and Period2 (Per2) mRNA were significantly altered in the mouse liver in Ptgfr-KO mice under DD. In the wild-type mouse, the plasma prostaglandin F2α (PGF2α) levels showed a circadian rhythm under a 12 h cycle of light-dark conditions. In addition, in vitro experiments showed that the addition of PTGFR agonists altered the amplitude of Per2::luc activity, and this alteration differed with the timing of the agonist addition. These results lead us to hypothesize that the plasma rhythm of PGF2α is important for driving clock genes, thus suggesting the involvement of PGF2α- and Ptgfr-targeting drugs in the biological clock cycle.

First Report of Colletotrichum gloeosporioides Causing Anthracnose on Peanut in Chongqing, China.

In July 2022, dieback and discoloration were detected on infected stems of peanut in Qijiang District of Chongqing (106.56°E,29.41°N), China, with an incidence up to 5%. These peanut stems had disease symptoms typical of anthracnose with irregular gray-brown spots with dark brown edges, sunken, and necrotic. High temperature and high humidity were favorable for the growth of the pathogen. To isolate the pathogen, we collected 10 typical infected peanuts and cut one piece from each of symptomatic stems, surface sterilized with 0.5% NaClO for 1 min, and 75% ethanol for 30 s, then rinsed three times with sterile distilled water and dried on sterilized filter paper. These pieces were incubated on potato dextrose agar (PDA) at 25°C in the dark. Pure cultures were obtained from hyphal tips of each colony. It was found that isolates with the same colony morphology were isolated from each infected stem. A representative isolate (L7) was used for morphological characterization, molecular analysis, phylogenetic analysis, and pathogenicity tests. The colonies appeared white to gray, with white margins and aerial hyphae, and the reverse of the colonies was gray to brown. Conidia were cylindrical, aseptate, with obtuse to slightly rounded ends, 13.4 to 18.8 × 4.2 to 5.8 μm (n=50). Morphological characteristics were generally consistent with those of Colletotrichum gloeosporioides species complex (Cannon et al., 2012). For molecular identification, genomic DNA was extracted using a CTAB method and partial sequences of β-tubulin (TUB2), actin (ACT) genes, chitin synthase (CHS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were amplified and sequenced using primers T1/T2, ACT-512F/ACT-783R, CHS-79F/CHS-345R, and GDF1/GDR1, respectively (Damm et al., 2012; Dowling et al., 2020). Using the BLAST, TUB2, ACT, CHS and GAPDH gene sequences (GenBank accession No. OR714793, OP168707, OP168708 and OR714794, respectively) were100% (429 bp out of 429 bp), 99.22% (256 bp out of 258 bp), 99.64% (276 bp out of 277 bp) and 100% (253 bp out of 253 bp) identical to C. gloeosporioides CBS:112999 (JQ005587, JQ005500, JQ005326, and JQ005239), respectively. Using Neighbor-Joining algorithm, phylogenetic analysis was conducted based on the concatenated sequences of published TUB2, ACT, CHS and GAPDH genes. The identified isolate (L7) was closely related to C. gloeosporioides. To evaluate pathogenicity, the stems of ten peanut (Zhonghua12) seedlings (2 weeks) were wounded with a sterile toothpick and mycelial plugs (5 mm in diameter) or 20 μl of conidial suspension (105/ml) were inoculated. Non-colonized agar plugs or 20 μl of sterile distilled water were treated as control. After inoculation, the peanuts were kept in a moist chamber at 28°C with 80% humidity in the dark for 24 h, and subsequently transferred to the moist chamber with 12 h light and darkness cycle for 6 days, similar symptoms were observed on all inoculated peanuts. Controls remained asymptomatic. C. gloeosporioides was reisolated from the diseased stems and confirmed using morphological features and sequence analysis of TUB2, ACT, CHS and GAPDH. Anthracnose caused by C. truncatum and C. fructicola has been reported on peanut leaves in China (Gong et al., 2023; Yu et al., 2019). To our knowledge, this is the first report of anthracnose on peanut stem caused by C. gloeosporioides in Chongqing. Our report will provide crucial information for studying on epidemiology and management of this disease.

Influence of light and dark cycle on recovery from ketamine and xylazine anesthesia in mice

Influence of light and dark cycle on recovery from ketamine and xylazine anesthesia in mice

Promoting student interest in plant biology through an inquiry-based module exploring plant circadian rhythm, gene expression, and defense against insects.

We present a weeklong curricular module for high school biology students that promotes knowledge of phytohormones, the circadian clock, and the Central Dogma. The module, which relies on easily accessible items and requires minimal space, integrates a hands-on experiment that guides students through replicating research examining circadian entrainment in postharvest cabbage from groceries. This work found that plants have cyclical, circadian expression of genes that produce phytohormones, and that such cyclical expression influences herbivory by caterpillars. Such cyclical patterns were found in plants both in situ and in postharvest cabbage. This work thus provides an ideal platform to shape student conceptions of circadian rhythms, gene expression, and plant herbivory by having students use light timers to entrain postharvest cabbage to alternating light and dark cycles and then measuring herbivory in these plants. The results should replicate previous work and demonstrate less herbivory when both plant and caterpillar are entrained to the same light and dark cycles since the expression of phytohormones involved in plant defense will be greatest when caterpillars are active. The module then concludes with a discussion of gene regulation and how this influences phytohormones. This module was field tested at four public schools, reaching over 600 students, and we present data demonstrating that the module led to learning gains and likely increases in interest in plant biology and self-efficacy.

Programmable Photoswitchable Microcapsules Enable Precise and Tailored Drug Delivery from Microfluidics.

The development of precision personalized medicine poses a significant need for the next generation of advanced diagnostic and therapeutic technologies, and one of the key challenges is the development of highly time-, space-, and dose-controllable drug delivery systems that respond to the complex physiopathology of patient populations. In response to this challenge, an increasing number of stimuli-responsive smart materials are integrated into biomaterial systems for precise targeted drug delivery. Among them, responsive microcapsules prepared by droplet microfluidics have received much attention. In this study, we present a UV-visible light cycling mediated photoswitchable microcapsule (PMC) with dynamic permeability-switching capability for precise and tailored drug release. The PMCs were fabricated using a programmable pulsed aerodynamic printing (PPAP) technique, encapsulating an aqueous core containing magnetic nanoparticles and the drug doxorubicin (DOX) within a poly(lactic-co-glycolic acid) (PLGA) composite shell modified by PEG-b-PSPA. Selective irradiation of PMCs with ultraviolet (UV) or visible light (Vis) allows for high-precision time-, space-, and dose-controlled release of the therapeutic agent. An experimentally validated theoretical model was developed to describe the drug release pattern, holding promise for future customized programmable drug release applications. The therapeutic efficacy and value of patternable cancer cell treatment activated by UV radiation is demonstrated by our experimental results. After in vitro transcatheter arterial chemoembolization (TACE), PMCs can be removed by external magnetic fields to mitigate potential side effects. Our findings demonstrate that PMCs have the potential to integrate embolization, on-demand drug delivery, magnetic actuation, and imaging properties, highlighting their immense potential for tailored drug delivery and embolic therapy.

Crickets in the spotlight: exploring the impact of light on circadian behavior.

Crickets serve as a well-established model organism in biological research spanning various fields, such as behavior, physiology, neurobiology, and ecology. Cricket circadian behavior was first reported over a century ago and prompted a wealth of studies delving into their chronobiology. Circadian rhythms have been described in relation to fundamental cricket behaviors, encompassing stridulation and locomotion, but also in hormonal secretion and gene expression. Here we review how changes in illumination patterns and light intensity differentially impact the different cricket behaviors as well as circadian gene expression. We further describe the cricket's circadian pacemaker. Ample anatomical manipulations support the location of a major circadian pacemaker in the cricket optic lobes and another in the central brain, possibly interconnected via signaling of the neuropeptide PDF. The cricket circadian machinery comprises a molecular cascade based on two major transcriptional/translational negative feedback loops, deviating somewhat from the canonical model of Drosophila and emphasizing the significance of exploring alternative models. Finally, the nocturnal nature of crickets has provided a unique avenue for investigating the repercussions of artificial light at night on cricket behavior and ecology, underscoring the critical role played by natural light cycles in synchronizing cricket behaviors and populations, further supporting the use of the cricket model in the study of the effects of light on insects. Some gaps in our knowledge and challenges for future studies are discussed.

Effects of Soy Protein Isolate on Fragile X Phenotypes in Mice.

Obesity is a pediatric epidemic that is more prevalent in children with developmental disabilities. We hypothesize that soy protein-based diets increase weight gain and alter neurobehavioral outcomes. Our objective herein was to test matched casein- and soy protein-based purified ingredient diets in a mouse model of fragile X syndrome, Fmr1KO mice. The experimental methods included assessment of growth; 24-7 activity levels; motor coordination; learning and memory; blood-based amino acid, phytoestrogen and glucose levels; and organ weights. The primary outcome measure was body weight. We find increased body weight in male Fmr1KO from postnatal day 6 (P6) to P224, male wild type (WT) from P32-P39, female Fmr1KO from P6-P18 and P168-P224, and female Fmr1HET from P9-P18 as a function of soy. Activity at the beginning of the light and dark cycles increased in female Fmr1HET and Fmr1KO mice fed soy. We did not find significant differences in rotarod or passive avoidance behavior as a function of genotype or diet. Several blood-based amino acids and phytoestrogens were significantly altered in response to soy. Liver weight was increased in WT and adipose tissue in Fmr1KO mice fed soy. Activity levels at the beginning of the light cycle and testes weight were greater in Fmr1KO versus WT males irrespective of diet. DEXA analysis at 8-months-old indicated increased fat mass and total body area in Fmr1KO females and lean mass and bone mineral density in Fmr1KO males fed soy. Overall, dietary consumption of soy protein isolate by C57BL/6J mice caused increased growth, which could be attributed to increased lean mass in males and fat mass in females. There were sex-specific differences with more pronounced effects in Fmr1KO versus WT and in males versus females.

Adolescent social isolation increases binge-like alcohol drinking in male but not female high-alcohol-preferring mice.

This study examined how adolescent social isolation affects adult binge-like alcohol drinking and stress-axis function, via basal levels of circulating corticosterone (CORT), in male and female mice with a genetic predisposition toward high alcohol preference (HAP). Male and female HAP2 mice were randomly assigned to a group-housed or social isolation (ISO) group. Social isolation began at postnatal Days 40-42 and lasted for 21days prior to assessment of binge-like alcohol drinking using a 4-day drinking-in-the-dark (DID) procedure. Blood samples to assess basal CORT were taken 6days after social isolation ended and 24h before DID started, and again 60h after DID ended, during the light portion of the light cycle. Adolescent social isolation increased adult binge-like alcohol drinking in male but not female mice. All groups showed significantly lower CORT after DID compared to before DID. Pearson bivariate correlation coefficients between the first 2h of grams-per-kilogram alcohol intake on Day 4 and CORT levels indicated a significant positive correlation in ISO males only after DID and negative correlations in ISO females before and after DID. These findings demonstrate that adolescent social isolation increased binge-like alcohol drinking in male but not female adult HAP2 mice. Stress-axis adaptations in male HAP2 mice may be associated with the social-isolation-induced increase in binge-like alcohol drinking.

Experimental and neural network prediction of the cyclic stability and light absorption characteristics of supercritical CO2 based CNTs nanofluids

Traditional working fluids face challenges including constrained heat transfer efficiency and inadequate thermal stability, which are detrimental to the thermal efficiency of energy conversion systems. To overcome these limitations and achieve a profound breakthrough in the field of energy conversion, it is imperative to develop innovative working fluids. Consequently, this study builds a nanofluid circulation flow experimental platform and prepares a supercritical carbon dioxide/hydroxylated multi-walled carbon nanotubes nanofluid. The study conducts a series of meaningful experimental tests and performance predictions, including stability analysis, deposition characterization research, light absorption potential investigation, and artificial neural network prediction. Remarkably, the artificial neural network model exhibits excellent learning capacity in training, validation, and testing, with root mean square error of only 9.069 W/m2, 8.9996 W/m2, and 13.0143 W/m2, respectively. Test results indicate that the nanofluid reaches a steady state after 4 min, with a fluctuation amplitude of only 2.13 %. Furthermore, the deposition density of the nanofluid on nickel sheet saturates after 4 h, confirming its considerable potential for promotion and application. The light absorption capacity and power decay rate of the nanofluid are enhanced by 606–881 W/m2 and 32.3–46.99 %, compared to other typical substances. The transmittance is reduced by 8.51–22.96 % compared to other nanofluids. The nanofluid proves to be an effective alternative to conventional working fluids, providing a practical reference solution for researchers aiming to improve working fluids in the field of energy conversion.

Adaptive Traffic Control Using Cooperative Communication Through Visible Light

The study aims to create a Visible-Light Communication (VLC) system for secure vehicle management at intersections. This involves enabling communication between vehicles and infrastructure (V2V, V2I, and I2V) using headlights, streetlights, and traffic signals. Mobile optical receivers gather data, determine their location, and read transmitted information through joint transmission. An intersection manager coordinates traffic and communicates with vehicles through embedded Driver Agents. The system utilizes a "mesh/cellular" hybrid network configuration and encodes data into light signals emitted by transmitters. Optical sensors and filtering properties enable reception and decoding. The study demonstrates bidirectional communication, employing queue/request/response mechanisms and relative pose concepts for safe vehicle passage. A deep reinforcement learning model controls traffic light cycles, validated via simulation in a Simulation of Urban Mobility simulator. Results show that this adaptive traffic control system effectively collects detailed vehicle data and ensures secure communication within the short-range mesh network.

Obesity-Resistant Mice on a High-Fat Diet Display a Distinct Phenotype Linked to Enhanced Lipid Metabolism.

Individually, metabolic variations can significantly influence predisposition to obesity in the form of the obesity-prone (super-responders) and obesity-resistant (non-responders) phenotypes in response to modern calorie-dense diets. In this study, C57BL/6J mice (n = 76) were randomly assigned to either a low-fat diet (LFD) or a high-fat diet (HFD) for 6 weeks, followed by selection of the normally obese (HFD), non-responders (NR), super-responders (SR), or super-responders switched back to the low-fat diet (SR-LFD) for an additional 8 weeks. SR mice showed the highest gains in body weight, lean and fat body mass, and total and free water, in part due to increased feed efficiency, despite having a respiratory exchange ratio (RER) similar to that of NR mice. A switch to the LFD was sufficient to revert most of the observed physiological changes in the SR-LFD mice; however, voluntary physical activity and exercise capacity did not return to the basal level. NR mice showed the highest food intake, lowest feed efficiency, increased oxygen consumption during the light (rest) cycle, increased physical activity during the dark (active) cycle, and increased heat production during both cycles. These variations were observed in the absence of changes in food intake and fecal parameters; however, NR fecal lipid content was lower, and the NR fecal microbiome profile was characterized by reduced abundance of Actinobacteria. Taken together, our findings suggest that NR mice showed an increased ability to metabolize excessive dietary fats in skeletal muscle at the expense of reduced exercise capacity that persisted for the duration of the study. These findings underscore the need for further comprehensive investigations into the mechanisms of obesity resistance, as they hold potential implications for weight-loss strategies in human subjects.

Susceptibility of centipede tongavine (Epipremnum pinnatum) commercially grown in nurseries in Florida to aroid leaf rust (Pseudocerradoa paullula).

Epipremnum pinnatum (L.) Engl., (Araceae, Monocots) known as dragon-tail plant or centipede tongavine, is the most cultivated aroid species worldwide (Boyce 2004). In 2022, symptomatic dragon-tail plants, collected from plant nurseries in south Florida (e-Xtra Fig.1). Symptoms included round leaf spots often with a yellow halo and erupting pustules mainly distributed in the underside of the leaves. Visits to the nurseries revealed a 60% incidence of approximability 50 mature plants, with some leaves showing up to 30% of tissue damage. The putative pathogen was identified morphologically as Pseudocerradoa paullula (Syd. & P. Syd.) M. Ebinghaus & Dianese (Pucciniaceae, Basidiomycota) (Ebinghaus et al. 2022), characterized by the production of pseudosuprastomatal uredinia with globose to subglobose urediniospores, light-brown, echinulate (1 µm height), 24-31 µm diam with thick walls, 1.5-2.5 µm in height (n=30). Identical morphological features reported by Urbina et al. (2023) (e-Xtra Fig. 1). PCR amplification followed by Sanger sequencing of the internal transcribed spacer (ITS) and large subunit (LSU) of the ribosomal RNA genes (Aime 2006) together with LSU internal species specific primer (Urbina et al. 2023) were used to confirm the identification of the pathogen (GenBank ON887194-ON887196). MegaBlast (Chen et al. 2015) searches resulted in a >99% sequence similarity to a P. paullula specimen collected in Florida (2019-101665, GenBank ON887197). Host identification was made by using the Ribulose-1,5-bisphosphate carboxylase-oxygenase (rbcL. GenBank ON887186, ON887187) and Maturase K (matK) loci (GenBank ON887190, ON887191) (Fazekas et al. 2012). Both barcodes resulted in >99.13% sequence similarity to voucher J.R. Abbott 24912 FLAS (GenBank GU135198 and GU135036, respectively). Symptomatic dried specimens were deposited in the Plant Industry Herbarium (PIHG 16229 - 16232). Koch's postulates were fulfilled using urediniospores collected from an infected E. pinnatum sample that was kept in darkness at 4°C for seven days until inoculation. Eight potted dragon-tail plants were inoculated by hand rubbing urediniospores against upper and lower leaf surfaces and three plants were used as controls. All plants were misted with sterile water and covered with plastic bags (23 °C, >90% RH, 12/12 h daylight). Bags were removed 48 h after inoculation, plants were set in a climate-controlled greenhouse (~30 °C, ~65% RH, 12/12 h light cycle) and monitored daily for symptoms. Chlorotic spots appeared after 10 days, and pustules after 25 days while the non-inoculated controls remained symptomless. Aroid leaf rust is known to infect several aroid species, including dragon-tail (Shaw 1995), which some varieties capable to outdoors in USDA 9a hardiness zones (Wunderlin et al. 2023), but the rust fungus has not been observed on any species of Epipremnum in the landscape yet, suggesting that its susceptibility could be driven by plant growth conditions that favor pathogen infection (e.g., excess of humidity and nutrients, dense planting, overhead irrigation, etc.). Here we encourage dragon-tail plant growers to be aware of its susceptibility to P. paullula and to stay vigilant of the culture conditions to avoid plants from getting infected with this airborne pathogen.

Light cycling as a key to understanding the outdoor behaviour of perovskite solar cells

The long-term outdoor performance and stability of Perovskite Solar Cells showed several features that stem from the device's meta-stability. To rationalize this behavior we need indoor ageing experiments with cycled light.

Photoresponsive hydrogel friction.

Photoresponsive hydrogels are an emerging class of stimuli-responsive materials that exhibit changes in physical or chemical properties in response to light. Previous investigations have leveraged photothermal mechanisms to achieve reversible changes in hydrogel friction, although few have focused on photochemical means. To date, the tribological properties of photoswitchable hydrogels (e.g., friction and lubrication) have remained underexplored. In this work, we incorporated photoresponsive methoxy-spiropyran-methacrylate monomers (methoxy-SP-MA) into a hydrogel network to form a copolymerized system of poly(N-isopropylacrylamide-co-2-acrylamido-2-methylpropane sulfonic acid-co-methoxy-spiropyran-methacrylate) (p(NIPAAm-co-AMPS-co-SP)). We demonstrated repeatable photoresponsive changes to swelling, friction, and stiffness over three light cycles. Our findings suggest that volume changes driven by the decreased hydrophilicity of the methoxy-SP-MA upon light irradiation are responsible for differences in the mechanical and tribological properties of our photoresponsive hydrogels. Our results could inform future designs of photoswitchable hydrogels for applications ranging from biomedical applications to soft robotics.

Red, blue or mix: choice of optimal light qualities for enhanced plant growth and development through in silico analysis

Abstract In smart greenhouse farming, the impact of light qualities on plant growth and development is crucial but lacks systematic identification of optimal combinations. This study addresses this gap by analysing various light properties’ effects (photoperiod, intensity, ratio, light–dark order) on Arabidopsis thaliana growth using days-to-flower (DTF) and hypocotyl length as proxies to measure plant growth and development. After establishing suitable ranges through a comprehensive literature review, these properties varied within those ranges. Compared to white light, a 16-h cycle of blue light reduces DTF and hypocotyl length by 12 % and 3 %, respectively. Interestingly, similar results can be achieved using a shorter photoperiod of 14-h light (composed of 8 h of a mixture of 66.7 μmol m−2s−1 red and 800 μmol m−2s−1 blue lights (i.e. blue:red ratio of 12:1) followed by 6 h of monochromatic red light and 10-h dark. These findings offer potential for efficient growth light recipes in smart greenhouse farming, optimizing productivity while minimizing energy consumption.

Fiber-based hydrophobic and stretchable UV-photochromic textile

Wearable sensors composed of fabric have attracted considerable research interest as they can detect various environmental factors that affect the human body, such as ultraviolet (UV) radiation, temperature, and humidity. Among these sensors, color-conversion sensors are especially valuable as they can provide a visual representation of data without the need for additional electrical devices. For a sensor to be used on the human body, it must maintain its sensing capabilities even when exposed to solutions such as rainwater, sweat, and various cleansing liquids or when subjected to mechanical deformation. Therefore, this study was aimed at fabricating a UV-photochromic fiber that can maintain its color-change reaction to UV light even when exposed to chemical and physical stressors. To this end, UV-photochromic pigment was infused into porous and hydrophobic silica aerogels to create UV-photochromic aerogels, which were then placed between the inner strands of spandex fibers. During the drying process, the UV-photochromic aerogels adhered firmly to the spandex strands and were not separated even when the fibers were stretched and contracted up to 100 times under 200% tensile conditions. The resulting UV-photochromic fibers initially appeared white but transformed to magenta when exposed to UV light. This color change persisted through seven repeated on–off cycles of UV light. Moreover, the hydrophobic nature of the fibers ensured that the color-change reactivity remained stable even under exposure to water, artificial sweat, and detergent solutions. Overall, the proposed UV-photochromic fibers, with enhanced reversibility, stability, and reliability, can promote the commercialization of wearable-based colorimetric sensors.

Role of melanocortin system in the locomotor activity rhythms and melatonin secretion as revealed by agouti-signalling protein (asip1) overexpression in zebrafish.

Temporal signals such as light and temperature cycles profoundly modulate animal physiology and behaviour. Via endogenous timing mechanisms which are regulated by these signals, organisms can anticipate cyclic environmental changes and thereby enhance their fitness. The pineal gland in fish, through the secretion of melatonin, appears to play a critical role in the circadian system, most likely acting as an element of the circadian clock system. An important output of this circadian clock is the locomotor activity circadian rhythm which is adapted to the photoperiod and thus determines whether animals are diurnal or nocturnal. By using a genetically modified zebrafish strain known as Tg (Xla.Eef1a1:Cau.asip1)iim04, which expresses a higher level of the agouti signalling protein 1 (Asip1), an endogenous antagonist of the melanocortin system, we observed a complete disruption of locomotor activity patterns, which correlates with the ablation of the melatonin daily rhythm. Consistent with this, in vitro experiments also demonstrated that Asip1 inhibits melatonin secretion from the zebrafish pineal gland, most likely through the melanocortin receptors expressed in this gland. Asip1 overexpression also disrupted the expression of core clock genes, including per1a and clock1a, thus blunting circadian oscillation. Collectively, these results implicate the melanocortin system as playing an important role in modulating pineal physiology and, therefore, circadian organisation in zebrafish.

THERAPEUTIC AND ANTAGONIST VILLI INSURGENCY OF GARCINIA KOLA ON ACETIC ACID INDUCED EROSIVE SMALL INTESTINAL ULCER OF WISTAR ALBINO RATS MODEL

The small bowel, also known as the small intestine, is a key component of the digestive system responsible for the majority of nutrient absorption from food. Positioned between the stomach and the large intestine, it receives digestive enzymes from bile and pancreatic juice via the pancreatic duct. The small intestine measures approximately 18 feet (6.5 meters) in length and is intricately folded to fit within the abdominal cavity. The Garcinia Kola plant was recognized by the Department of Pharmacology at Niger Delta University, located on Wilberforce Island, Amasomma, Bayelsa State. The seeds of this plant were collected from Amasomma and subjected to a drying process under natural sunlight for 14 days. Subsequently, they were ground into a fine powder and distributed into various beakers. After allowing the mixture to settle for three days, it was filtered using Watchman's No. 1 filter paper. For this research, thirty albino rats with weights ranging from 150g ± 3.5 to 205g ± 2.6 were utilized. These rats were sourced from the animal facility of the Pharmacology Department at Niger Delta University. They were kept in a controlled environment with temperatures maintained between 20°C and 27°C and a 12-hour cycle of light and darkness. The rats were grouped and provided with standard feed pellets from Guinea Feed Nigeria Plc and unlimited access to clean water for the duration of the study, which included a two-week acclimatization period. The handling of the animals adhered to the institution's guidelines for animal experimentation. The study spanned two months, with an initial four-week acclimatization phase. Post-acclimatization, the 30 rats were randomly assigned to seven groups (A to G). Group A (control) received a diet of pelleted growers feed (mash) and water. Group B (chronic exposure group) was given 1ml of 4% acetic acid orally, along with the standard diet, for 30 days. Group C (subchronic exposure group) received the same acetic acid treatment for 14 days. Groups D and E (sub-chronic exposure groups) were treated with acetic acid and varying doses of Garcinia Kola extract for 14 days. Groups F and G (chronic exposure groups) underwent a similar regimen with Garcinia Kola extract for 30 days. At the end of the treatment period, the rats were euthanized using chloroform anesthesia, and vital organs were harvested and preserved in 10% formalin. The tissues underwent standard histological processing and were stained with Haematoxylin and Eosin at the Histopathology laboratory of the Niger Delta Teaching Hospital (NDUTH) in Okolobiri. Histological examination revealed that the control group's villi and submucosal walls remained intact. However, plates 4.2 to 4.4 displayed erosion of the submucosal layer, interruption of the villi, and aggregation of white blood cells. Plate 4.5 indicated mild erosion of the mucosal layer and the presence of inflammatory cells. The findings suggest that oral ingestion of acetic acid for 30 days can cause inflammation and necrosis in the stomach tissues of lab animals. Additionally, it was noted that administering Garcinia Kola seed extract alone had minimal impact on the animals' histology.