A review of experimental investigations and assessment methods for masonry arch bridges

Masonry arch bridges constitute a significant proportion of European road and rail infrastructures. Most of them are well over 100 years old and are supporting traffic loads many times above those originally envisaged. The inherent variation in their constituent materials, the traditional design criteria and methods used for their construction, their deterioration over time caused by weathering processes and the development of other defects, significantly influence the mechanical response of these historic structures. A deep understanding on the numerous factors that affect the structural behaviour of masonry arch bridges and on the analysis methods to assess the life expectancy of such bridges and inform maintenance and strengthening strategies is essential. This paper provides a critical review of the experimental studies that have been carried out and of the assessment approaches that have been developed in the last three decades to these aims. The current knowledge is established and areas of possible future research work are identified, with the aim of providing students and researchers, asset managers and bridge owners, and practitioners with a guidance for research activities and maintenace strategies.     

Electronic coupling between azurin and gold at different protein/substrate orientations

By means of constrained classical molecular dynamics simulations, we have computed the structure of azurin deposited on a Au(111) surface at different possible orientations and the azimuthal forces acting on the protein at each sampled conformation. We have then evaluated the effect of the angular variation on the speed of electron tunneling between the protein redox site and the metal surface. We find that the azurin/gold electronic coupling has a strong dependence on the molecular orientation and is greatly enhanced by inclining the protein to lie as flat as possible on the surface. We discuss the implications of our results for scanning probe microscopy experiments in which tunneling currents are measured while the protein is subjected to mechanical forces exerted by the tip of the instrument.     

Iron Chelates: Production Processes and Reaction Evolution Analysis

Nowadays, fertilization using synthetic chelates is the most common technique to address iron chlorosis, a disease that affects plant growth. Ethylenediamine-N,N'-bis(o-hydroxyphenyl) acetic acid (EDDHA) is among the most efficient iron chelating agents. To produce EDDHA, a reaction was performed using as reactants phenol, ethylenediamine, glyoxylic acid, and sodium hydroxide. To study the reaction kinetics, samples were withdrawn from the reactor during the reaction and the kinetics was quantified, evaluating the yield evolution during the reaction phase. This study was useful to optimize the reaction time. Then, a catalyst was added to the reaction mixture to analyze its effect on the reaction evolution. Comparing the reaction evolution of the non-catalyzed and the catalyzed reaction protocols, two main results have to be highlighted: the time to reach the final yield is lower than the one proposed in the literature and the used catalyst has a minimum effect on the reaction rate.     

Congenital diarrheal disorders: an updated diagnostic approach

Congenital diarrheal disorders (CDDs) are a group of inherited enteropathies with a typical onset early in the life. Infants with these disorders have frequently chronic diarrhea of sufficient severity to require parenteral nutrition. For most CDDs the disease-gene is known and molecular analysis may contribute to an unequivocal diagnosis. We review CDDs on the basis of the genetic defect, focusing on the significant contribution of molecular analysis in the complex, multistep diagnostic work-up.     

Environmental factors affect the activity of biocontrol agents against ochratoxigenic Aspergillus carbonarius on wine grape

The influence of temperature and relative humidity (RH) on the activity of three biocontrol agents-the yeast Metschnikowia pulcherrima LS16 and two strains of the yeast-like fungus Aureobasidium pullulans LS30 and AU34-2-against infection by A. carbonarius and ochratoxin A (OTA) accumulation in wine grape berries was investigated in lab-scale experiments. The presence of wounds on grape skin dramatically favored infection of berries by A. carbonarius strain A1102, since unwounded berries showed very low levels of infection at all conditions of RH and temperature tested. Artificially wounded berries pre-treated with the biocontrol agents were inoculated with the ochratoxigenic A. carbonarius strain A1102 and were incubated for 5days at two levels of RH (60% and 100%) and three different temperatures (20, 25 and 30°C). The three biocontrol agents were able to prevent infections at 60% RH and 20°C. At 60% RH and 25°C only strain AU34-2 achieved some protection on day 5, whereas at 30°C a limited biocontrol efficacy was evident only up to day 2. At 100% RH, LS16, LS30 and AU34-2 showed effective protection of grape berries at 20°C until the 5th day of incubation. The three biocontrol agents achieved significant protection at higher temperatures only until the 2nd day after the beginning of the experiment: all three strains at 25°C, and only strain LS16 at 30°C. After 5days, the three biocontrol agents were able to significantly reduce the level of OTA in berries at all the conditions tested. This occurred even when protection from infection was not significant, except at 30°C and 100% of RH for all the three strains, and at 25°C and 100% of RH for strain LS16. The biocontrol agents displayed a higher rate of colonization on grape berries at 20 and 25°C than at 30°C. The higher value of RH (100%) appeared to increase the rate of colonization, in particular at 20 and 25°C. Taken together, our results emphasize the significant influence of environmental factors on the effectiveness of biocontrol against A. carbonarius as well as on OTA contamination in wine grape berries, and the need for biocontrol agents that can cope with the environmental conditions that are conducive to attack by A. carbonarius.     

Interactions of Spike-RBD of SARS-CoV-2 and Platelet Factor 4: New Insights in the Etiopathogenesis of Thrombosis

The rare but dangerous adverse events evidenced after massive vaccination against SARS-CoV-2 are represented by thrombosis and thrombocytopenia. The patients diagnosed with severe COVID-19 may develop a pro-thrombotic state with a much higher frequency, thus we decided to investigate the role of Spike protein (the only common product of the two conditions) or the anti-Spike antibodies in the etiopathogenesis of thrombosis. A pathogenic Platelet Factor 4 (PF4)-dependent syndrome, unrelated to the use of heparin therapy, has been reported after the administration of vaccines in the patients manifesting acute thrombocytopenia and thrombosis. Thus, we aimed at shedding light on the structural similarities of Spike of SARS-CoV-2 and PF4 on their eventual biochemical interactions and on the role of their specific antibodies. The similarities between PF4 and Spike-RBD proteins were evaluated by a comparison of the structures and by testing the cross-reactivity of their specific antibodies by ELISA assays. We found that the anti-Spike antibodies do not recognize PF4, on the contrary, the anti-PF4 antibodies show some cross-reactivity for Spike-RBD. More interestingly, we report for the first time that the PF4 and Spike-RBD proteins can bind each other. These data suggest that the interaction of the two proteins could be involved in the generation of anti-PF4 antibodies, their binding to Spike-RBD, which could lead to platelets aggregation due also to their high expression of ACE2.     

Low life purpose and high hostility are related to an attenuated decline in nocturnal blood pressure.

Objective: An attenuation of the nighttime decline in blood pressure (BP) predicts cardiovascular disease and cardiovascular-related mortality, beyond daytime BP levels. We investigated whether positive and negative psychological attributes were associated with sleep–wake BP ratios and examined sleep parameters as potential mediators of these relationships. Design: Two hundred twenty-four participants (50% men; 43% Black; mean age = 60 years) underwent ambulatory BP monitoring for 2 days and nights. Self-reports of positive and negative psychological attributes were collected. In-home polysomnography was conducted for 2 nights, and a wrist actigraph was worn for 9 nights. Main Outcome Measures: Sleep–wake mean arterial pressure (MAP) ratios. Results: After adjustment for demographics, body mass index, and hypertensive status, low life purpose and high hostility were associated with high sleep–wake MAP ratios. Depression, anxiety, and optimism were not related to MAP ratios. Sleep latency, fragmentation, architecture, and the apnea–hypopnea index were examined as potential mediators between psychological attributes and MAP ratios; only long sleep latency mediated the relationship between hostility and MAP ratios. Conclusion: Low life purpose and high hostility are associated with high sleep–wake BP ratios in Black and White adults, and these relationships are largely independent of sleep. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

OPERA: a novel method to reduce ghost and aliasing artifacts

Objective

A method for Orthogonal Phase Encoding Reduction of Artifact (OPERA) was developed and tested.

Materials and methods

Because the position of ghosts and aliasing artifacts is predictable along columns or rows, OPERA combines the intensity values of two images acquired using the same parameters, but with swapped phase-encoding directions, to correct the artifacts. Simulations and phantom experiments were conducted to define the efficacy, robustness, and reproducibility. Clinical validation was performed on a total of 1003 images by comparing the OPERA-corrected images and the corresponding image standard in terms of Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR). The method efficacy was also rated using a Likert-type scale response by two experienced independent radiologists using a single-blinded procedure.

Results

Simulations and phantom experiments demonstrated the robustness and effectiveness of OPERA in reducing artifacts strength. OPERA application did not significantly change the SNR [+?4.16%; inter-quartile range (IQR): 2.72–5.01%] and CNR (+?4.30%; IQR: 2.86–6.04%) values. The two radiologists observed a total of 893 original images with artifacts (89.03% of the total images), a reduction in the perceived artifacts of 82.0% and 83.9% (p?<?0.0001), and an improvement in the perceived SNR (82.8% and 88.5%; K?=?0.714) and perceived CNR (86.9–88.9%; K?=?0.722).

Discussion

The study demonstrated that OPERA reduces MR artifacts and improves the perceived image quality.

     

Human Aquaporin-4 and Molecular Modeling: Historical Perspective and View to the Future

Among the different aquaporins (AQPs), human aquaporin-4 (hAQP4) has attracted the greatest interest in recent years as a new promising therapeutic target. Such a membrane protein is, in fact, involved in a multiple sclerosis-like immunopathology called Neuromyelitis Optica (NMO) and in several disorders resulting from imbalanced water homeostasis such as deafness and cerebral edema. The gap of knowledge in its functioning and dynamics at the atomistic level of detail has hindered the development of rational strategies for designing hAQP4 modulators. The application, lately, of molecular modeling has proved able to fill this gap providing a breeding ground to rationally address compounds targeting hAQP4. In this review, we give an overview of the important advances obtained in this field through the application of Molecular Dynamics (MD) and other complementary modeling techniques. The case studies presented herein are discussed with the aim of providing important clues for computational chemists and biophysicists interested in this field and looking for new challenges.     

Effects of carbonaceous nanoparticles from low-emission and older diesel engines on human skin cells

Diesel exhaust particles (DEP) are major constituents of ambient air pollution and are associated with respiratory and cardiovascular diseases as well skin cell alterations in vitro. The epidermal cells are among the first cell populations exposed to chemical pollutants, including DEP, and are an important source of pro-inflammatory mediators. We evaluated the effects of carbonaceous soot particles from current low-emission (Euro IV) diesel engines on the oxidative and inflammatory response of normal human skin cells and compared the results with those induced by carbonaceous soot particles from an older diesel engine (BS) operating under black smoke conditions. We observed that both soot nanoparticles were spontaneously internalised by keratinocytes and distributed mostly around the cell nucleus. Moreover, at the same mass concentration, Euro IV soot particles exhibited a much higher oxidative, pro-fibrotic and toxic potential on these cell types than soot particles from the older diesel engine. These results are in agreement with and confirm our previous findings on human macrophage cells and strengthen the assumption that, at the same mass concentration, soot particles produced under low emission conditions are more cytotoxic than particles from the older diesel engine. This effect could be assigned to the defective surface structure of Euro IV diesel soot, rendering it highly active. Our findings highlight that the reduction of soot emission in terms of mass does not automatically lead to a reduction of the dangerous effects and show that soot particles from different diesel engines possess different biological behaviour towards human cells.