Impact of Ethylene Oxide Butylene Oxide Copolymers on the Composition and Friction of Silicone Hydrogel Surfaces

The surface chemical compositions of three types of silicone hydrogel contact lenses, PureVision^® (balafilcon A), ACUVUE^® OASYS^® (senofilcon A), and O₂OPTIX^® (lotrafilcon B), were analyzed using X-ray photoelectron spectroscopy prior to and following treatment in a test solution of diblock copolymer of poly(ethylene oxide) and poly(butylene oxide) (EO–BO). Prior to treatment, differences in surface elemental compositions of the lenses were found to reflect known bulk compositions and/or respective surface treatments. Following solution treatment, surface chemical modifications were apparent in balafilcon A and lotrafilcon B, especially in the distribution of chemical functionalities present at the surface. Only modest changes in surface composition were observed for the senofilcon A material. Atomic force microscopy (AFM) was employed to evaluate the surface topography and frictional properties of the lenses prior to and following similar solution treatments. AFM measurements in saline revealed large disparities between the coefficients of friction of the three lenses, with balafilcon A and lotrafilcon B exhibiting coefficients of friction approximately five times greater than that of senofilcon A. Lens surface treatment with the diblock copolymer test solution produced a significant reduction in the coefficients of friction of the two lenses exhibiting higher friction, yet only a small reduction in friction was observed for senofilcon A lens. Together, these results depict a strong correlation between the surface chemistry and frictional response of the lens systems as they relate to solution treatment with this specific diblock copolymer.     

Impact of nanotube density and alignment on the elastic modulus near the top and base surfaces of aligned multi-walled carbon nanotube films

The mechanical compliance of vertically aligned carbon nanotube (VACNT) films renders them promising as interface materials that can accommodate thermal expansion mismatch. Here we study the relationship between the detailed morphology and elastic modulus of multi-walled VACNT films with thicknesses ranging from 98 to 1300 μm. A systematic analysis of scanning electron micrographs reveals variations in nanotube alignment and density among samples and within different regions of a given film. Nanoindentation of both top and bottom film surfaces using an atomic force microscope with spherical indenters with radii between 15 and 25 μm provides evidence of the modulus differences. The top surface is shown to have a higher modulus than the base, with out-of-plane modulus values of 1.0–2.8 MPa (top) and 0.2–1.4 MPa (base). The indentation data and microstructural information obtained from electron microscopy are interpreted together using an open cell foam model to account for differences in nanotube alignment and density, which are generally lower at the base and yield predictions that are consistent with the modulus data trends. This work shows that microstructure analysis complements property measurements to improve our understanding of nanostructured materials.     

Agriculture’s role in the Indian enigma: help or hindrance to the crisis of undernutrition?

In recent decades India has achieved one of the fastest economic growth rates in the world, yet its progress against both child and adult undernutrition has been sluggish at best. While this Indian variant of the so-called Asian enigma presents many puzzles, one of the puzzles pertains to agriculture’s role. Many researchers and policymakers have high expectations of agriculture’s potential to reduce undernutrition, despite a lack of substantive evidence. In this paper we assess this tenuous evidence base by exploring two key channels by which agricultural production conditions can influence nutritional outomes: a food consumption pathway and a maternal employment–time use pathway. We conclude with an appraisal of some possible entry points for pro-nutrition agricultural policies.     

Long-Run Trends in Victorian Housing Affordability and First Transition into Homeownership

Over the past two decades housing pathways have become increasingly differentiated between generations, particularly in advanced societies dominated by owner-occupied tenure systems. Demographic transformations caused by aging and falling fertility rates, along with a more volatile economy and a neo-liberal reorientation of governance have combined to restructure housing conditions. Drawing on empirical research in Japan, this paper illustrates the social origins and impact of generation-based differentiations in housing patterns in that country. It considers the housing experiences of three cohorts: baby-boomers, baby-busters and the ‘lost generation’. The contrast of housing pathways between these generations in Japan illustrates the contemporary dynamics of housing and social processes in homeowner societies.     

The Signaling Pathway of TNF Receptors: Linking Animal Models of Renal Disease to Human CKD

Chronic kidney disease (CKD) has been recognized as a global public health problem. Despite the current advances in medicine, CKD-associated morbidity and mortality remain unacceptably high. Several studies have highlighted the contribution of inflammation and inflammatory mediators to the development and/or progression of CKD, such as tumor necrosis factor (TNF)-related biomarkers. The inflammation pathway driven by TNF-α, through TNF receptors 1 (TNFR1) and 2 (TNFR2), involves important mediators in the pathogenesis of CKD. Circulating levels of TNFRs were associated with changes in other biomarkers of kidney function and injury, and were described as predictors of disease progression, cardiovascular morbidity, and mortality in several cohorts of patients. Experimental studies describe the possible downstream signaling pathways induced upon TNFR activation and the resulting biological responses. This review will focus on the available data on TNFR1 and TNFR2, and illustrates their contributions to the pathophysiology of kidney diseases, their cellular and molecular roles, as well as their potential as CKD biomarkers. The emerging evidence shows that TNF receptors could act as biomarkers of renal damage and as mediators of the disease. Furthermore, it has been suggested that these biomarkers could significantly improve the discrimination of clinical CKD prognostic models.     

Peptide Human Neutrophil Elastase Inhibitors from Natural Sources: An Overview

Elastases are a broad group of enzymes involved in the lysis of elastin, the main component of elastic fibres. They are produced and released in the human body, mainly by neutrophils and the pancreas. The imbalance between elastase activity and its endogenous inhibitors can cause different illnesses due to their excessive activity. The main aim of this review is to provide an overview of the latest advancements on the identification, structures and mechanisms of action of peptide human neutrophil elastase inhibitors isolated from natural sources, such as plants, animals, fungi, bacteria and sponges. The discovery of new elastase inhibitors could have a great impact on the pharmaceutical development of novel drugs through the optimization of the natural lead compounds. Bacteria produce mainly cyclic peptides, while animals provide for long and linear amino acid sequences. Despite their diverse natural sources, these elastase inhibitors show remarkable IC₅₀ values in a range from nM to μM values, thus representing an interesting starting point for the further development of potent bioactive compounds on human elastase enzymes.     

The Role of Vitamin D in Supporting Health in the COVID-19 Era

The genomic activity of vitamin D is associated with metabolic effects, and the hormone has a strong impact on several physiological functions and, therefore, on health. Among its renowned functions, vitamin D is an immunomodulator and a molecule with an anti-inflammatory effect, and, recently, it has been much studied in relation to its response against viral infections, especially against COVID-19. This review aims to take stock of the correlation studies between vitamin D deficiency and increased risks of severe COVID-19 disease and, similarly, between vitamin D deficiency and acute respiratory distress syndrome. Based on this evidence, supplementation with vitamin D has been tested in clinical trials, and the results are discussed. Finally, this study includes a biochemical analysis on the effects of vitamin D in the body’s defense mechanisms against viral infection. In particular, the antioxidant and anti-inflammatory functions are considered in relation to energy metabolism, and the potential, beneficial effect of vitamin D in COVID-19 is described, with discussion of its influence on different biochemical pathways. The proposed, broader view of vitamin D activity could support a better-integrated approach in supplementation strategies against severe COVID-19, which could be valuable in a near future of living with an infection becoming endemic.     

Morphogen Signals Shaping the Gastric Glands in Health and Disease

The adult gastric mucosa is characterised by deep invaginations of the epithelium called glands. These tissue architectural elements are maintained with the contribution of morphogen signals. Morphogens are expressed in specific areas of the tissue, and their diffusion generates gradients in the microenvironment. Cells at different positions in the gland sense a specific combination of signals that instruct them to differentiate, proliferate, regenerate, or migrate. Differentiated cells perform specific functions involved in digestion, such as the production of protective mucus and the secretion of digestive enzymes or gastric acid. Biopsies from gastric precancerous conditions usually display tissue aberrations and change the shape of the glands. Alteration of the morphogen signalling microenvironment is likely to underlie those conditions. Furthermore, genes involved in morphogen signalling pathways are found to be frequently mutated in gastric cancer. We summarise the most recent findings regarding alterations of morphogen signalling during gastric carcinogenesis, and we highlight the new stem cell technologies that are improving our understanding of the regulation of human tissue shape.     

Validation of a Cleanroom Compliant Sonication-Based Decellularization Technique: A New Concept in Nerve Allograft Production

Defects of the peripheral nervous system are extremely frequent in trauma and surgeries and have high socioeconomic costs. If the direct suture of a lesion is not possible, i.e., nerve gap > 2 cm, it is necessary to use grafts. While the gold standard is the autograft, it has disadvantages related to its harvesting, with an inevitable functional deficit and further morbidity. An alternative to autografting is represented by the acellular nerve allograft (ANA), which avoids disadvantages of autograft harvesting and fresh allograft rejection. In this research, the authors intend to transfer to human nerves a novel technique, previously implemented in animal models, to decellularize nerves. The new method is based on soaking the nerve tissues in decellularizing solutions while associating ultrasounds and freeze–thaw cycles. It is performed without interrupting the sterility chain, so that the new graft may not require post-production γ-ray irradiation, which is suspected to affect the structural and functional quality of tissues. The new method is rapid, safe, and inexpensive if compared with available commercial ANAs. Histology and immunohistochemistry have been adopted to evaluate the new decellularized nerves. The study shows that the new method can be applied to human nerve samples, obtaining similar, and, sometimes better, results compared with the chosen control method, the Hudson technique.