SARS-CoV-2 Spike Protein Binding of Glycated Serum Albumin—Its Potential Role in the Pathogenesis of the COVID-19 Clinical Syndromes and Bias towards Individuals with Pre-Diabetes/Type 2 Diabetes and Metabolic Diseases

The immune response to SARS-CoV-2 infection requires antibody recognition of the spike protein. In a study designed to examine the molecular features of anti-spike and anti-nucleocapsid antibodies, patient plasma proteins binding to pre-fusion stabilised complete spike and nucleocapsid proteins were isolated and analysed by matrix-assisted laser desorption ionisation–time of flight (MALDI-ToF) mass spectrometry. Amongst the immunoglobulins, a high affinity for human serum albumin was evident in the anti-spike preparations. Careful mass comparison revealed the preferential capture of advanced glycation end product (AGE) forms of glycated human serum albumin by the pre-fusion spike protein. The ability of bacteria and viruses to surround themselves with serum proteins is a recognised immune evasion and pathogenic process. The preference of SARS-CoV-2 for AGE forms of glycated serum albumin may in part explain the severity and pathology of acute respiratory distress and the bias towards the elderly and those with (pre)diabetic and atherosclerotic/metabolic disease.     

Metrics-based profiling of university research engagement with Africa: research management,gender, and internationalization perspective

Scientometrics - U.S. university engagement with Africa in various areas including global health, education, environment, and agriculture has grown in the last 15 years. However, there is...     

Happiness versus sadness as a determinant of thought confidence in persuasion: A self-validation analysis.

The present research introduces a new mechanism by which emotion can affect evaluation. On the basis of the self-validation hypothesis (R. E. Petty, P. Bri?ol, & Z. L. Tormala, see record 2002-12575-003), the authors predicted and found that emotion can influence evaluative judgments by affecting the confidence people have in their thoughts to a persuasive message. In each study, participants first read a strong or weak persuasive communication. After listing their thoughts about the message, participants were induced to feel happy or sad. Relative to sad participants, those put in a happy state reported more thought confidence. As a consequence, the effect of argument quality on attitudes was greater for happy than for sad participants. These self-validation effects generalized across different emotion inductions, different persuasion topics, and different measures of thought confidence. In one study, happy and sad conditions each differed from a neutral affect control. Most important, these metacognitive effects of emotion only occurred under high elaboration conditions. In contrast, individuals with relatively low motivation to think showed a main effect of emotion on attitudes, regardless of argument quality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of alterations to action potential duration on beta-adrenoceptor-mediated aftercontractions in human and guinea-pig ventricular myocytes

Aftercontractions induced by beta-adrenoceptor stimulation in human and guinea-pig cardiomyocytes may be related to changes in action potential duration (APD). We investigated the effects of altering APD during the occurrence of isoproterenol-induced aftercontractions, using the KATP channel openers cromakalim and lemakalim or the action potential voltage clamp technique, in guinea-pig and human ventricular cardiomyocytes. Contractile responses were measured at 32 degrees C using a video-based edge-detection system. In guinea-pig myocytes, action potentials, Indo-1 fluorescence and contraction were measured at 22 degrees C. Isoproterenol (< or = 12 nM) had variable effects on APD but induced aftercontractions, the majority (14/19 cells) of which occurred during the action potential. Short action potentials were produced using K+ channel openers. These compounds reduced or completely abolished the isoproterenol-induced aftercontractions. Increasing isoproterenol in the presence of K+ channel opener restored the main contraction to a level similar to or above those with isoproterenol alone, but without the reappearance of aftercontractions. When cells were stimulated to contract under action potential voltage clamp, isoproterenol-induced aftercontractions were abolished by voltage clamping with action potentials of short duration. It was possible to induce aftercontractions in some cells without application of isoproterenol if voltage clamp-imposed action potentials of very long duration were used. These aftercontractions were also abolished by shortening action potential duration. We conclude that K+ channel openers or the imposition of action potentials of short duration can dissociate positively inotropic beta-adrenoceptor stimulation from aftercontraction formation and that action potentials of long duration can be pro-arrhythmic.     

Determining the Toughness of Ceramics from Vickers Indentations Using the Crack-Opening Displacements: An Experimental Study

Recently, a method for evaluating the fracture toughness of ceramics has been proposed by Fett based on the computed crack-opening displacements of cracks emanating from Vickers hardness indentations. To verify this method, experiments have been conducted to determine the toughness of a commercial silicon carbide ceramic, Hexoloy SA, by measuring the crack-opening profiles of such Vickers indentation cracks. Although the obtained toughness value of K _o= 2.3 MPa·m^1/2 is within 10% of that measured using conventional fracture toughness testing, the computed crack-opening profiles corresponding to this toughness display poor agreement with those measured experimentally, raising concerns about the suitability of this method for determining the toughness of ceramics. The effects of subsurface cracking and cracking during loading are considered as possible causes of such discrepancies, with the former based on direct observations of lateral subsurface cracks below the indents.     

Deducing the Fatigue Crack Growth Rates of Natural Flaws in Silicon Nitride Ceramics: Role of R‐Curves

Fatigue failure is a concern when high‐strength, high‐toughness silicon nitride ceramics are used in mechanical components and the growth of natural flaws will determine the usable upper bound strength. In this study a fracture resistance curve (R‐curve) model is incorporated into an established method for deducing natural flaw growth rates from a combination of strength and fatigue life data for smooth specimens. Experimental data for a commercial silicon nitride, SL200, were examined. When compared with results deduced using a constant fracture toughness model, the new method gives more physically realistic growth rate results. Specifically, by incorporating the R‐curve the deduced fatigue threshold is equal to the reported intrinsic toughness for crack propagation of 2.2 MPa√m, whereas the constant fracture toughness model gives a physically unrealistic threshold value. Furthermore, much better agreement is achieved with the growth rates measured using macroscopic compact‐tension specimens. Overall, it is concluded that the R‐curve effect should not be ignored when deducing the fatigue crack growth rates of natural flaws in high‐toughness silicon nitride ceramics.     

Plasma Processing of B4C–TiB2 Eutectic Composite Powders

The production of a composite powder of eutectic B₄C–TiB₂ is demonstrated via an atmospheric plasma processing method. Feedstock material is prepared for plasma processing by mixing and spray drying monolithic B₄C and TiB₂ to produce a flowable precursor powder. These powders are fed through a plasma torch, where they are melted and actively quenched in flight with argon gas. Plasma processed powders are composed of crystalline B₄C and TiB₂, with some additional B₂O₃ oxide phase. The plasma processing method results in the production of monolithic B₄C and TiB₂ nanoparticles, but some larger particles (generally ≥10 μm in diameter) are shown to contain the traditional lamellar eutectic microstructure. The eutectic interphase spacing ranges from 100 to 650 nm, and the composite microstructure is present through the entire thickness of the eutectic particles. Future work on plasma processing of eutectic powders should focus on methods utilizing passive in‐flight quenching to increase the average particle size.     

The Effect of Lowering the Surface Free Energy of Water on the Thermodynamic Work of Adhesion

The dispersive and polar force components of surface free energy have been measured for water left in contact with films dried from various emulsion adhesives. The polar component was lowered but the dispersive components were about 28 mJ m^?2 in each case. From these measurements of thermodynamic work of adhesion in the presence of contaminated water have been calculated for adhesive-polystyrene interfaces. An equation has been derived giving the dependence of thermodynamic work of adhesion upon the total surface free energy of water. It shows that the thermodynamic work of adhesion decreases as the surface free energy of water is lowered, but it eventually reaches a minimum and then may increase slightly.