Mathematical Modeling and Experimental Substantiation of the Gas Release Process in the Production of Non-Autoclaved Aerated Concrete

The widespread use of aerated concrete in construction has led to the emergence of many types and compositions. However, additional research should fill theoretical gaps in the phenomenon of gas release during the formation of the structure of aerated concrete. Based on theoretical analysis and experimental studies, the article proposes a mathematical model of the swelling process based on the physicochemical laws of convection and molecular diffusion of hydrogen from a mixture and the conditions of swelling, precipitation, and stabilization of the mixture. An improved method for the manufacture of aerated concrete is proposed, which consists of introducing cement pre-hydrated for 20–30 min into the composition of the aerated concrete mixture and providing improved gas-holding capacity and increased swelling of the mixture, reducing the average density of aerated concrete up to 29% and improving heat-shielding properties up to 31%. At the same time, the small dynamics of a decrease in the strength properties of aerated concrete were observed, which is confirmed by an increased structural quality factor (CSQ) of up to 13%. As a result, aerated concrete has been obtained that meets the requirements of environmental friendliness and has improved mechanical and physical characteristics. Economic efficiency is to reduce the cost of production of aerated concrete and construction in general by about 15%.     

Wearable microfluidic-based e-skin sweat sensors

Electronic skins (e-skins) are soft (deformable and stretchable) state-of-the-art wearable devices that emulate the attributes of human skin and act as a Human–Machine Interface (HMI). Recent advances in e-skin for real-time detection of medical signals such as pulse, temperature, electromyogram (EMG), electroencephalogram (EEG), electrooculogram (EOG), electrocardiogram (ECG), and other bioelectric signals laid down an intelligent foundation for early prediction and diagnosis of diseases with a motive of reducing the risk of the ailment reaching to the end stage. In particular, sweat testing has been employed in diverse applications ranging from medical diagnosis of diabetes, cystic fibrosis, tuberculosis, blood pressure, and autonomic neuropathy to evaluating fluid and electrolyte balance in athletes. Typically, sweat testing techniques are done by trained experts and require off-body measurements, which prevent individuals from de-coding health issues quickly and independently. With the onset of soft electronics, wearable sweat sensors overcome this disadvantage via in situ sweat measurements with real-time feedback, timely diagnosis, creating the potential for preventive care and treatment. Over the past few decades, wearable microfluidic-based e-skin sweat sensors have paved a new way, promising sensing interfaces that are highly compatible with arranging medical and electronic applications. The present review highlights the recent research carried out in the microfluidic-based wearable sweat sensors with a critical focus on real-time sensing of lactate, chloride, and glucose concentration; sweat rate, simultaneously with pH, and total sweat loss for preventive care, timely diagnosis, and point-of-care health and fitness monitoring.

Electronic skins are soft wearable devices that emulate attributes of human skin and act as a human–machine interface for early prediction and real-time monitoring of disease.     

Utilization of a rodent model to examine the neurological effects of early life adversity on adolescent pain sensitivity

All children experience pain, and although many recover quickly, some go on to develop chronic pain. Adolescent chronic pain is a growing epidemic. It is unknown why some adolescents recover without incident and others experience persistent pain. Although unexplored, early life adversity may contribute to the development and maintenance of chronic pain. This study investigated the effects and underlying neurobiological mechanisms of an early life stressor on nociceptive (pain) sensitivity and emotional function in male and female Sprague-Dawley rats. Using maternal separation (MS) as an established model of early life stress, we addressed two aims: investigation of the effects of MS on behavior (anxiety and pain sensitivity), and investigation of the effects of MS on mRNA and pathophysiological changes associated with an acutely painful stimulus. Our results indicate that MS increased anxiety-like behavior and altered nociceptive responsivity in adolescent rats, with decreased mechanical withdrawal thresholds indicative of heightened and prolonged pain-related behavior. The MS groups also demonstrated increased expression of genes involved in regulating the stress and fight-or-flight response, mood, and neuroplasticity; as well as increased levels of inflammatory markers. We conclude that nociception, both at the behavioral and molecular level, is altered in response to the MS stressor.     

Target-specific PIP2 signalling: how might it work?

Phosphatidylinositol 4,5-bisphosphate (PIP₂)-mediated signalling is a new and rapidly developing area in the field of cellular signal transduction. With the extensive and growing list of PIP₂-sensitive membrane proteins (many of which are ion channels and transporters) and multiple signals affecting plasma membrane PIP₂ levels, the question arises as to the cellular mechanisms that confer specificity to PIP₂-mediated signalling. In this review we critically consider two major hypotheses for such possible mechanisms: (i) clustering of PIP₂ in membrane microdomains with restricted lateral diffusion, a hypothesis providing a mechanism for spatial segregation of PIP₂ signals and (ii) receptor-specific buffering of the global plasma membrane PIP₂ pool via Ca²⁺-mediated stimulation of PIP₂ synthesis or release, a concept allowing for receptor-specific signalling with free lateral diffusion of PIP₂. We also discuss several other technical and conceptual intricacies of PIP₂-mediated signalling.     

Sexual Dimorphism of Digit‐Length Ratio in a Viviparous Lizard: Influence of Age,but not Preservation State or Sex of Interuterine Twin

The existence of sex differences in digit‐length ratio (especially between the second and fourth digits, 2D:4D) is well established for humans from fetal life onwards, and has been linked with later performance. In rodents, the ratio is affected prenatally by exposure to androgens and estrogens, with some research suggesting an influence from sex of the neighbouring intrauterine fetus. However, the ubiquity and ontogenetic development of sexual dimorphism in digit ratios is not well established among wild amniotes. We report the first digit ratios for a gekkotan lizard, representing a speciose lineage in which viviparity has evolved independently from mammals and other reptiles. For the gecko Woodworthia “Otago/Southland”, in which up to two embryos develop in separate uteri, we found: (1) significant sexual dimorphism in adults in 2D:3D of the right hindlimb only (larger in males), but not in 2D:4D for any limb; (2) no dimorphism in ratios for young juveniles, with no influence of sex of the interuterine twin, and no relationship with sprint speed; (3) in preserved tissues of the same juveniles, no sexual dimorphism in ratios, but a change in relative lengths of some digits with preservation. The ontogenetic pattern might be explained by altered sex–steroid exposure at the transition to adulthood rather than during prenatal development. Our results support a phylogenetic hypothesis that sauropsids (birds and reptiles) differ from mammals in the direction of sex difference, if present. Experiments are needed to establish the roles of androgens and estrogens in establishing these sex differences in lizards. Anat Rec, 301:1169–1178, 2018. © 2018 Wiley Periodicals, Inc.