Structure Refinement and Fragmentation of Precipitates under Severe Plastic Deformation: A Review

During severe plastic deformation (SPD), the processes of lattice defect formation as well as their relaxation (annihilation) compete with each other. As a result, a dynamic equilibrium is established, and a steady state is reached after a certain strain value. Simultaneously, other kinetic processes act in opposite directions and also compete with each other during SPD, such as grain refinement/growth, mechanical strengthening/softening, formation/decomposition of solid solution, etc. These competing processes also lead to dynamic equilibrium and result in a steady state (saturation), albeit after different strains. Among these steady-state phenomena, particle fragmentation during the second phase of SPD has received little attention. Available data indicate that precipitate fragmentation slows down with increasing strain, though saturation is achieved at higher strains than in the case of hardness or grain size. Moreover, one can consider the SPD-driven nanocrystallization in the amorphous phase as a process that is opposite to the fragmentation of precipitates. The size of these crystalline nanoprecipitates also saturates after a certain strain. The fragmentation of precipitates during SPD is the topic of this review.

Hot deformation behavior of 60NiTi shape-memory alloy fabricated by hot isostatic pressing

The 60NiTi (Ni60wt%–Ti40wt%) intermetallic is a hard-to-process material. Understanding of hot deformation behavior is crucial for the hot working of 60NiTi. This work studied hot deformation behavior and corresponding microstructure of the hot isostatic pressed 60NiTi in the temperature range of 900 °C–1050 °C and at strain rates of 0.1, 0.01, and 0.001 s-1 through a hot compression test. The flow stress and microstructure were susceptible to the hot deformation parameters. The flow stress decreased with the increase in deformation temperature and decrease in strain rate. Work hardening occurred at a small strain, then followed by softening; finally, near-dynamic equilibrium was achieved between work hardening and softening. A constitutive equation was developed to describe the effects of strain rate and temperature on flow stress. Simulation of hot deformation via the finite element method revealed the workpiece’s inhomogeneous deformation. The deformation occurred mainly in the center area of the cylindrical sample, resulting in high stress and strain concentrations in this region and causing the equiaxial grains to be compressed into prolate grains. This work can provide guidance for the hot working, such as forging and hot rolling, of 60NiTi.

Trends of Healthy Life Expectancy of the Elderly in China in 1994–2015: Revisiting From the Perspective of Morbidity Transition

Research on healthy life expectancy (HLE) in China has been fueled by a spate of new data sources and studies, yet no consensus is reached on the pattern of HLE changes and the underlying mechanism. This study examined the change of HLE in China over 20 years with long term national data. Health status, measured by activities of daily living, is combined with mortality to calculate the disability-free life expectancy by the Sullivan method. The results show that the HLE rose slower than life expectancy (LE) in 1994–2004, indicating morbidity expansion. However, in 2010–2015, the proportion of HLE to LE increased, manifesting morbidity compression. A counterfactual analysis further shows that health improvement has been increasingly important in increasing HLE in 2010–2015, despite the dominance of mortality decline. The findings suggest that morbidity can transition between compression, expansion and dynamic equilibrium over a long period due to different combinations of mortality and health improvements. Given the limited data in this study, whether and how morbidity transitions unfold in the future remains open and requires further research.

A Novel Protective Mechanism for Melatonin Against Acute Lung Injury: Preserving Mitochondrial Dynamic Equilibrium of Lung Epithelial Cells Through SIRT3-Dependent Deacetylation of SOD2

Mitochondrial dynamic equilibrium of lung epithelial cells is disturbed during sepsis, which contributes to abnormal mitochondrial function and acute lung injury (ALI). Melatonin is one primary hormone secreted by the pineal gland, displaying favorable antioxidative actions in sepsis and cardiopulmonary disease. However, the potential roles and molecular basis of melatonin in lipopolysaccharide (LPS)-treated lung epithelial cells have not been explored and reported. Herein, we investigated whether melatonin could protect against sepsis-induced ALI and lipopolysaccharide (LPS)-treated lung epithelial cells through mitochondrial dynamic equilibrium as well as its possible molecular targets. Wild type and Sirt3 knockout mice were instilled with LPS intratracheally for 12 hours to construct an in vivo ALI model. And A549 lung epithelial cells were used to explore the possible roles of melatonin in vitro by incubating with small interfering RNA (siRNA) against Sirt3. To figure out the involvement of melatonin receptor, si Mtnr1b and luzindole were used in cells and mice. Melatonin pretreatment significantly inhibited pathological injury, inflammatory response, oxidative stress and apoptosis in LPS-treated lung tissues and LPS-treated lung epithelial cells. Meanwhile, melatonin also shifted the dynamic course of mitochondria from fission into fusion in LPS-treated lung epithelial cells in vivo and in vitro. However, SIRT3 inhibition abolished the protective roles of melatonin in ALI. Mechanistically, we found that melatonin increased the activity and expression of SIRT3, which further promoted the deacetylation of SOD2 at K122 and K68. More importantly, melatonin exerted pulmonary protection by activating MTNR1B but not MTNR1A in ALI. Collectively, melatonin could preserve mitochondrial dynamic equilibrium of lung epithelial cells through the deacetylation of SOD2 in a SIRT3-dependent manner, which eventually alleviated LPS-elicited injury, inflammation, oxidative stress, apoptosis. Thus, melatonin may serve as a promising candidate against ALI in the future.

Settlers in Earthquake Country

This article examines how settlers in New Zealand and California responded to seismic instability throughout the late nineteenth century. By interpreting a series of moments during which the foundations of settlement were shaken by earthquakes I argue that the economic temporality of colonial boom and bust inflected contemporary understandings of natural disaster. In earthquake country, the relationships between scientists and settlers, their environmental knowledge, and the physical world existed in a dynamic equilibrium. When earthquakes struck in opportune conditions settlers were quick to resume their speculation on land, scientists were inspired by upheaval, and artists found sublimity in instability. In times of doubt earthquakes induced a latent anxiety among settlers about the prospects of the colonial project. In this context natural disasters were framed as threats to growth or harbingers of decline. Read together, responses to earthquakes offer a new way into the environmental history of settler colonialism that places a form of creative destruction at the center of the colonial project on both sides of the Pacific Rim.

Nutrigenetics and nutrigenomics: A brief review with future prospects

Individual’s genetic makeup best describes the properties regarding its growth and development. It is stored and passed on to generations and is in dynamic equilibrium with the environmental and other non-living factors. The most predominant environmental stimuli are diet/nutrition. Diet/nutrition interacts and modulates varying underlying molecular mechanisms central to various physiological functions basically at three different levels: genome, proteome, and metabolome. Advances in genomic studies are paving the way to the development of scientific insights into nutritional sciences. Nutrigenetics and nutrigenomics are closely associated but two different areas of nutritional research. Both the fields involved the study of the implication between nutrition, metabolism, and genetic mechanism. The primary goal is to pinpoint nutrient-dependent health characteristics and nutrition dependent diseases. Another important area connected to these sciences concerns food composition and performance of quality assessment by studying proteomics and metabolic pathways. Nutrigenomics explains how the nutrients influences or effects the expression of the, while the response of different gene variants to nutrients or different dietary components is called Nutrigenetics. A personalized based diet can help us to know the right nutrient to take or avoid those who may potentially harm overall health. The goals are intended to alter or decrease the impact of hostile dietary changes that have occurred in since past in the developed world and more recently in the developing countries.

A Dynamic Modeling Method for the Bi-Directional Pneumatic Actuator Using Dynamic Equilibrium Equation

Dynamic modeling of soft pneumatic actuators are a challenging research field. In this paper, a dynamic modeling method used for a bi-directionaly soft pneumatic actuator with symmetrical chambers is proposed. In this dynamic model, the effect of uninflated rubber block on bending deformation is considered. The errors resulting from the proposed dynamic equilibrium equation are analyzed, and a compensation method for the dynamic equilibrium equation is proposed. The equation can be solved quickly after simplification. The results show that the proposed dynamic model can describe the motion process of the bi-directional pneumatic actuator effectively.

Music Listening and Homeostatic Regulation: Surviving and Flourishing in a Sonic World

This paper argues for a biological conception of music listening as an evolutionary achievement that is related to a long history of cognitive and affective-emotional functions, which are grounded in basic homeostatic regulation. Starting from the three levels of description, the acoustic description of sounds, the neurological level of processing, and the psychological correlates of neural stimulation, it conceives of listeners as open systems that are in continuous interaction with the sonic world. By monitoring and altering their current state, they can try to stay within the limits of operating set points in the pursuit of a controlled state of dynamic equilibrium, which is fueled by interoceptive and exteroceptive sources of information. Listening, in this homeostatic view, can be adaptive and goal-directed with the aim of maintaining the internal physiology and directing behavior towards conditions that make it possible to thrive by seeking out stimuli that are valued as beneficial and worthy, or by attempting to avoid those that are annoying and harmful. This calls forth the mechanisms of pleasure and reward, the distinction between pleasure and enjoyment, the twin notions of valence and arousal, the affect-related consequences of music listening, the role of affective regulation and visceral reactions to the sounds, and the distinction between adaptive and maladaptive listening.