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In the animal kingdom, sexually dimorphic color variation is a widespread phenomenon that significantly influences survival and reproductive success. However, the genetic underpinnings of this variation remain inadequately understood. Our investigation into sexually dimorphic color variation in the desert-dwelling Guinan population of the toad-headed agamid lizard (Phrynocephalus putjatai) utilized a multidisciplinary approach, encompassing phenotypic, ultrastructural, biochemical, genomic analyses, and behavioral experiments. Our findings unveil the association between distinct skin colorations and varying levels of carotenoid and pteridine pigments. The red coloration in males is determined by a genomic region on chromosome 14, housing four pigmentation genes: BCO2 and three 6-pyruvoyltetrahydropterin synthases. A Guinan population-specific nonsynonymous single nucleotide polymorphism in BCO2 is predicted to alter the electrostatic potential within the binding domain of the BCO2-β-carotene complex, influencing their interaction. Additionally, the gene MAP7 on chromosome 2 emerges as a potential contributor to the blue coloration in subadults and adult females. Sex-specific expression patterns point to steroid hormone-associated genes (SULT2B1 and SRD5A2) as potential upstream regulators influencing sexually dimorphic coloration. Visual modeling and field experiments support the potential selective advantages of vibrant coloration in desert environments. This implies that natural selection, potentially coupled with assortative mating, might have played a role in fixing color alleles, contributing to prevalence in the local desert habitat. This study provides novel insights into the genetic basis of carotenoid and pteridine-based color variation, shedding light on the evolution of sexually dimorphic coloration in animals. Moreover, it advances our understanding of the driving forces behind such intricate coloration patterns. [ABSTRACT FROM AUTHOR]

Fiber‐enhanced Raman spectroscopy is applied actively for gas analysis. Hollow‐core anti‐resonant fibers (HC‐ARFs) with low loss and low spatial overlap between core and cladding modes show the potential of low background. We integrated an HC‐ARF into the Raman system, collected the forward scattering radiation with a lens‐coupled imaging spectrometer, and filtered most of the background through selection of region of interest. The limits of detection (LODs) of this system were determined as 1.2 ppm·bar for CH4, 2.9 ppm·bar for C2H6, 1.6 ppm·bar for C2H4, 2.7 ppm·bar for C2H2, 13.8 ppm·bar for H2, and 16.7 ppm·bar for CO with the excitation laser of 200 mW and the exposure time of 60 s. In addition, the LOD was better than 2.5 ppm·bar for H2S. By the detection of gas samples with the critical detectable concentration, it was proven that the estimated values of LOD from the preceding experimental results are reliable and the system had practical detectability. The gas samples we tested are relevant for multiple fields such as industrial process control and environment monitoring, showing the diversified application prospects of the Raman gas analysis system based on HC‐ARF. [ABSTRACT FROM AUTHOR]

Size changes in brain and brain regions along altitudinal gradients provide insight into the trade‐off between energetic expenditure and cognitive capacity. We investigated the brain size variations of the Asiatic Toad (Bufo gargarizans) across altitudes from 700 m to 3,200 m. A total of 325 individuals from 11 sites and two transects were sampled. To reduce confounding factors, all sampling sites within each transect were within a maximum distance of 85 km and an altitudinal difference close to 2,000 m. Brains were dissected, and five regions were both measured directly and with 3D CT scan. There is a significant negative correlation between the relative whole‐brain volume (to snout‐vent length) and altitude. Furthermore, the relative volumes (to whole‐brain volume) of optic tectum and cerebellum also decrease along the altitudinal gradients, while the telencephalon increases its relative volume along the gradients. Therefore, our results are mostly consistent with the expensive brain hypothesis and the functional constraint hypothesis. We suggest that most current hypotheses are not mutually exclusive and data supporting one hypothesis are often partially consistent with others. More studies on mechanisms are needed to explain the brain size evolution in natural populations. [ABSTRACT FROM AUTHOR]

Brain size variation is often attributed to energetic trade-offs with other metabolically expensive tissues and organs, which is a prediction of the expensive brain hypothesis (EBH). Here we examine Asiatic toads (Bufo gargarizans) along altitudinal gradients, and test size trade-offs between brain and four visceral organs (heart, liver, alimentary tract, and kidney) with altitude. Body size and scaled mass index (SMI; a proxy for total energy intake) decline with altitude, implying stronger energetic constraints at high altitudes. Relative brain size decreases along altitudinal gradients while visceral organs mostly increase in relative sizes. Using structural equation modelling, a significant negative relationship between brain size and a latent variable 'budget', which represents the energy allocation to the four visceral organs, is detected among high-altitudinal toads. Heart appears to have the largest and most consistent response to changes of energy allocation. No such relationships are observed among toads at middle and low altitudes, where high energy intake may allow individuals to forego energetic trade-offs. When applying EBH to poikilotherms, a great emphasis should be placed on total energy intake in addition to energy allocation. Future research on EBH will benefit from more intra-specific comparisons and the evaluation of fitness consequences beyond energy limitation., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Society for the Study of Evolution (SSE).)

Polycarbonate (PC) as a widely used engineering plastic that shows disadvantages of flammability and large smoke production during combustion. Although many flame-retardant PCs have been developed, most of them show enhanced flame retardancy but poor smoke suppression or worsened mechanical performance. In this work, a novel nitrogen-phosphorus-sulfur synergistic flame retardant (Pc-FR) was synthesized and incorporated into PC with polytetrafluoroethylene (PTFE). The extremely low content of PC-FR (0.1-0.5 wt%) contributes significantly to the flame retardancy, smoke suppression and mechanical performance of PC. PC/0.3 wt% Pc-FR/0.3 wt% PTFE (PC-P0.3) shows the UL-94 V-0 and LOI of 33.5%. The PHRR, THR, PSPR, PCO and TCO of PC-P0.3 decreased by 39.44%, 14.38%, 17.45%, 54.75% and 30.61%, respectively. The impact strength and storage modulus of PC-P0.1 increased by 7.7 kJ/m 2 and 26 MPa, respectively. The pyrolysis mechanism of PC-P0.3 is also revealed. The pyrolysis mechanism of PC-P0.3 is stochastic nucleation and subsequent growth and satisfies the Aevrami-Erofeev equation. The reaction order of PC-P0.3 is 1/2. The activation energy of PC-P0.3 is larger than PC-0, which proves that the Pc-FR can suppress the pyrolysis of the PC. This work offers a direction on how to design high-performance PC.