At Ta >40°C, however, RMR and EWL of females were significantly lower than those of males, by ∼13% and ∼17%, respectively, despite similar relationships between Tb and Ta, maximum ratio of evaporative heat loss to metabolic heat production and heat tolerance limits (∼50°C). These sex-specific differences in hornbill thermoregulation support the hypothesis that avian thermal physiology can vary within species in response to fine-scale microclimatic factors. In addition, Q10 for RMR varied substantially, with Q10 ≤2 in some individuals, supporting recent arguments that active metabolic suppression may be an underappreciated aspect of endotherm thermoregulation in the heat.Cranial morphology in lepidosaurs is highly disparate and characterised by the frequent loss or reduction of bony elements. In varanids and geckos, the loss of the postorbital bar is associated with changes in skull shape, but the mechanical principles underlying this variation remain poorly understood. Here, we sought to determine how the overall cranial architecture and the presence of the postorbital bar relate to the loading and deformation of the cranial bones during biting in lepidosaurs. Using computer-based simulation techniques, we compared cranial biomechanics in the varanid Varanus niloticus and the teiid Salvator merianae, two large, active foragers.  https://www.selleckchem.com/CDK.html  The overall strain magnitude and distribution across the cranium were similar in the two species, despite lower strain gradients in V. niloticus In S. merianae, the postorbital bar is important for resistance of the cranium to feeding loads. The postorbital ligament, which in varanids partially replaces the postorbital bar, does not affect bone strain. Our results suggest that the reduction of the postorbital bar impaired neither biting performance nor the structural resistance of the cranium to feeding loads in V. niloticus Differences in bone strain between the two species might reflect demands imposed by feeding and non-feeding functions on cranial shape. Beyond variation in cranial bone strain related to species-specific morphological differences, our results reveal that similar mechanical behaviour is shared by lizards with distinct cranial shapes. Contrary to the situation in mammals, the morphology of the circumorbital region, calvaria and palate appears to be important for withstanding high feeding loads in these lizards.Wing integrity is crucial to the many insect species that spend distinct portions of their life in flight. How insects cope with the consequences of wing damage is therefore a central question when studying how robust flight performance is possible with such fragile chitinous wings. It has been shown in a variety of insect species that the loss in lift-force production resulting from wing damage is generally compensated by an increase in wing beat frequency rather than amplitude. The consequences of wing damage for flight performance, however, are less well understood, and vary considerably between species and behavioural tasks. One hypothesis reconciling the varying results is that wing damage might affect fast flight manoeuvres with high acceleration, but not slower ones. To test this hypothesis, we investigated the effect of wing damage on the manoeuvrability of hummingbird hawkmoths (Macroglossum stellatarum) tracking a motorised flower. This assay allowed us to sample a range of movements at different temporal frequencies, and thus assess whether wing damage affected faster or slower flight manoeuvres. We show that hummingbird hawkmoths compensate for the loss in lift force mainly by increasing wing beat amplitude, yet with a significant contribution of wing beat frequency. We did not observe any effects of wing damage on flight manoeuvrability at either high or low temporal frequencies.
  Reduced risk perceptions influence young people's consumption behaviours of e-cigarettes, suggesting that a health halo effect may be associated with these devices. Product, performative, and social factors contribute to the appeal of e-cigarettes, with young people using e-cigarettes with friends as part of social interactions. This study explored the factors that influence the appeal and risk perceptions associated with e-cigarettes among young Cambodian men.
 
  A mixed-method, interviewer-administered survey with 147 young men in Cambodia, who were aged between 18 and 24 years and identified as cigarette smokers. Participants described their attitudes and consumption behaviours surrounding e-cigarettes, recalled e-cigarette promotions, and described their risk perceptions towards e-cigarettes. Descriptive statistics were calculated for quantitative data, and thematic analysis was conducted for qualitative data.
 
  Some participants associated e-cigarettes with affluence and exclusivity, describing these deg people to underestimate the potential health risks associated with these devices.
  In the USA, many states do not pre-empt municipalities from enacting stricter tobacco-control policies than state or federal laws. Several municipalities in Massachusetts have passed progressive local laws aimed at reducing adolescent tobacco use. We exploited this variability to examine the associations between county-level flavoured tobacco product restrictions, tobacco 21 policies and smoke-free laws prohibiting e-cigarettes with adolescent cigarette and e-cigarette use in Massachusetts, and to assess whether policy effects varied by age.
 
  We conducted difference-in-differences models to link changes in county-level tobacco-control policies to changes in adolescents' use of cigarettes and e-cigarettes using 2011-2017 biennial Massachusetts Youth Health Surveys.
 
  Counties with greater implementation of flavoured tobacco product restrictions were associated with a decrease in the level of cigarette use among users (incidence rate ratio -1.56; 95% CI -2.54 to -0.58). A significant interaction (p=0.03) revnt tobacco use and municipalities should enact stricter tobacco-control policies when not pre-empted by state law.Mitochondria are involved in many biological processes including cellular homeostasis, energy generation, and apoptosis. Moreover, mitochondrial and metabolic pathways are interconnected with gene expression to regulate cellular functions such as cell growth, survival, differentiation, and immune recognition. Metabolites and mitochondrial enzymes regulate chromatin-modifying enzymes, chromatin remodeling, and transcription regulators. Deregulation of mitochondrial pathways and metabolism leads to alterations in gene expression that promote cancer development, progression, and evasion of the immune system. This review highlights how mitochondrial and metabolic pathways function as a central mediator to control gene expression, specifically on stem cell functions, differentiation, and immune response in leukemia. SIGNIFICANCE Emerging evidence demonstrates that mitochondrial and metabolic pathways influence gene expression to promote tumor development, progression, and immune evasion. These data highlight new areas of cancer biology and potential new therapeutic strategies.