Bimodal nanostructured (NS) metals composed of coarse-grained (CG) and nano-/ultrafine-grained phases possess high strength and good ductility. In this paper, three-dimensional (3D) ...microstructure-based numerical simulations via the mechanism-based strain gradient plasticity and the Johnson–Cook failure model are performed to study the effects of the shape and distribution of CG inclusions on the strength and ductility of bimodal NS Cu. Our results show that both the shape and distribution of CG inclusions significantly affect the overall ductility, while the former has more prominent influences than the latter. Spherical CG inclusions result in excellent overall ductility under all considered spatial distributions, while CG inclusions with sharp edges and corners facilitate microcrack initiation. However, the earlier microcrack initiation does not necessarily lead to a lower ductility since proper combinations of the shape and distribution of CG inclusions may retard microcrack propagation and thus enhance the overall ductility. These 3D microstructure-based simulations are helpful for the design of bimodal NS metals with improved mechanical properties.
Research has shown that a stable thermal environment with tight temperature control cannot bring occupants more thermal comfort. Instead, such an environment will incur higher energy costs and ...produce greater CO2 emissions. Furthermore, this may lead to the degeneration of occupants' inherent ability to combat thermal stress, thereby weakening thermal adaptability. Measured data from many field investigations have shown that the human body has a higher acceptance to the thermal environment in free‐running buildings than to that in air‐conditioned buildings with similar average parameters. In naturally ventilated environments, occupants have reported superior thermal comfort votes and much greater thermal comfort temperature ranges compared to air‐conditioned environments. This phenomenon is an integral part of the adaptive thermal comfort model. In addition, climate chamber experiments have proven that people prefer natural wind to mechanical wind in warm conditions; in other words, dynamic airflow can provide a superior cooling effect. However, these findings also indicate that significant questions related to thermal comfort remain unanswered. For example, what is the cause of these phenomena? How we can build a comfortable and healthy indoor environment for human beings? This article summarizes a series of research achievements in recent decades, tries to address some of these unanswered questions, and attempts to summarize certain problems for future research.
Highly plastic endocrine traits are thought to play a central role in allowing organisms to respond rapidly to environmental change. Yet, not all individuals display the same degree of plasticity in ...these traits, and the costs of this individual variation in plasticity are unknown. We studied individual differences in corticosterone levels under varying conditions to test whether there are consistent individual differences in (1) baseline corticosterone levels; (2) plasticity in the hormonal response to an ecologically relevant stressor (food restriction); and (3) whether individual differences in plasticity are related to fitness costs, as estimated by oxidative stress levels. We took 25 wild-caught house sparrows into captivity and assigned them to repeated food restricted and control treatments (60% and 110% of their daily food intake), such that each individual experienced both food restricted and control diets twice. We found significant individual variation in baseline corticosterone levels and stress responsiveness, even after controlling for changes in body mass. However, these individual differences in hormonal responsiveness were not related to measures of oxidative stress. These results have implications for how corticosterone levels may evolve in natural populations and raise questions about what we can conclude from phenotypic correlations between hormone levels and fitness measures.
It has been reported previously that people who are acclimated to naturally ventilated (NV) environments respond to hot and warm environments differently than people who are acclimated to ...air‐conditioned (AC) environments. However, it is not clear whether physiological acclimatization contributes to this discrepancy. To study whether living and working in NV or AC environments for long periods of time can lead to different types of physiological acclimatization, and whether physiological acclimatization has an important influence on people’s responses of thermal comfort, measurements of physiological reactions (including skin temperature, sweat rate, heart rate variability, and heat stress protein 70) and thermal comfort responses were conducted in a ‘heat shock’ environment (climate chamber) with 20 people (10 in the NV group and 10 in the AC group). The results showed that the NV group had a significantly stronger capacity for physiological regulation to the heat shock than the AC group. In other words, the NV group did not feel as hot and uncomfortable as the AC group did. These results strongly indicate that living and working in indoor thermal environments for long periods of time affects people’s physiological acclimatization. Also, it appears that long‐term exposure to stable AC environments may weaken people’s thermal adaptability.
Practical Implications
This study examined the psychological and physiological differences of thermal adaptability of people used to air‐conditioned environments and naturally ventilated environments. The results suggested that long‐term exposure to stable air‐conditioned environments may weaken people’s thermal adaptability. Therefore, it might be advantageous for people to spend less time in static air‐conditioned environments; this is not only because of its possible deleterious impact on people’s physiological adaptability, but also because the air‐conditioners’ high‐energy consumption will contribute to the effects of global warming.
In this study, we explore the correlations between indoor climate change and human thermal adaptation, especially with regard to the timescale and weighting factors of physiological adaptation. A ...comparative experiment was conducted in China where wintertime indoor climate in the southern region (devoid of space heating) is much colder than in the northern region (with pervasive district heating). Four subject groups with different indoor thermal experiences participated in this climate chamber experiment. The results indicate that previous indoor thermal exposure is an important contributor to occupants’ physiological adaptation. More specifically, subjects acclimated to neutral‐warm indoors tended to have stronger physiological responses and felt more uncomfortable in moderate cold exposures than those adapted to the cold. As for the driving force of thermal adaptation, physiological acclimation is an important aspect among all the supposed adaptive layers. However, the physiological adaptation speed lags behind changes in the overall subjective perception.
The avian life cycle is composed by a progressive sequence of life history stages (LHS). Changes in energy expenditure and exposure to stressors at different LHS require corresponding changes in ...behavior, physiology, and morphology. Variation in hematological parameters, such hematocrit (Hct), hemoglobin (Hb), and heterophil to lymphocyte ratio (H/L ratio), can have permissive, stimulatory, and preparative actions to help maintain homeostasis through different LHS. Few studies have examined differences in these parameters among different LHS in free‐living birds, with most of them restricted to temperate zones. We collected blood samples and measured hematological parameters every week for over a year from a population of a common resident bird species in southeastern Brazil, the pale‐breasted thrush Turdus leucomelas. Hematocrit and hemoglobin concentration were highest during the onset of the reproduction and lowest during molt. Furthermore, H/L ratios were higher at the end of the reproduction, indicating that the breeding season could be the most stressful period of the year for this population of thrushes. There was no difference between sexes for any hematological parameter at any LHS. These results show that there is a permissive physiological effect for Hct and Hb to facilitate LHS transitions and that reproduction could be the most stressful event for this species. Lastly, these results mirror those from temperate species despite distinct environmental differences between these regions.
Background:
Pyrotinib is a novel irreversible pan-ErbB receptor tyrosine kinase inhibitor. Evidence of the efficacy of pyrotinib-based treatments for HER2-positive metastatic breast cancer (MBC) in ...patients exposed to lapatinib is limited.
Methods:
Ninety-four patients who received pyrotinib as a third- or higher-line treatment for HER2-positive MBC were included in this retrospective study. The primary and secondary endpoints were overall survival (OS) and progression‐free survival (PFS). Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) analysis were implemented to balance important patient characteristics between groups.
Results:
Thirty (31.9%) patients were pretreated with lapatinib and subsequently received pyrotinib as an anti-HER2 treatment, and 64 (68.1%) patients did not receive this treatment. The OS and PFS indicated a beneficial trend in lapatinib-naive group compared to lapatinib-treated group in either the original cohort (PFS: 9.02 vs 6.36 months,
p
= 0.05; OS: 20.73 vs 14.35 months,
p
= 0.08) or the PSM (PFS: 9.02 vs 6.08 months,
p
= 0.07; OS: 19.07 vs 18.00 months,
p
= 0.61) or IPTW (PFS: 9.90 vs 6.17 months,
p
= 0.05; OS: 19.53 vs 15.10 months,
p
= 0.08) cohorts. Subgroup analyses demonstrated lapatinib treatment-related differences in PFS in the premenopausal subgroup and the no prior trastuzumab treatment subgroup, but no significant differences were observed in OS.
Conclusion:
Pyrotinib-based therapy demonstrated promising effects in HER2-positive MBC patients in a real-world study, especially in lapatinib-naive patients, and also some activity in lapatinib-treated patients.
Disentangling the interaction between the genetic basis and environmental context underlying phenotypic variation is critical for understanding organismal evolution. Environmental change, such as ...increased rates of urbanization, can induce shifts in phenotypic plasticity with some individuals adapting to city life while others are displaced.
A key trait that can facilitate adaptation is the degree at which animals respond to stressors. This stress response, which includes elevation of baseline circulating concentrations of glucocorticoids, has a heritable component and exhibits intra‐ and inter‐individual variation. However, the mechanisms behind this variability and whether they might be responsible for adaptation to different environments are not known. Variation in DNA methylation can be a potential mechanism that mediates environmental effects on the stress response, as early‐life stressors increase glucocorticoid concentrations and change adult phenotype.
We used an inter‐ and intra‐environmental cross‐foster experiment to analyse the contribution of DNA methylation to early‐life phenotypic variation. We found that at hatching, urban house wren (Troglodytes aedon) offspring had higher methylation frequencies compared with their rural counterparts.
We also observed age‐related patterns in offspring methylation, indicating the developmental effects of the rearing environment on methylation. At fledgling, differential methylation analyses showed that cellular respiration genes were differentially methylated in broods of different origins and behavioural and metabolism genes were differentially methylated in broods of different rearing environments. Lastly, hyper‐methylation of a single gene (CNTNAP2) is associated with decreased glucocorticoid levels and the rearing environment.
These differential methylation patterns linked to a specific physiological phenotype suggest that DNA methylation may be a mechanism by which individuals adjust to novel environments during their lifespan. Characterizing genetic and environmental influences on methylation is critical for understanding the role of epigenetic mechanisms in evolutionary adaptation.
Species face rapidly changing environments and increased rates of urbanization. The authors used an inter‐ and intra‐environmental cross‐foster experiment to analyse the contribution of DNA methylation to early‐life phenotypic variation. They discovered different networks of genes were important at hatching compared with fledging and that DNA methylation shapes the physiological phenotype.
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