What Happens to MnO2 When It Comes in Contact with Zn2+? An Electrochemical Study in Aid of Zn/MnO2-Based Rechargeable Batteries

In the science and technology of electrochemical energy storage, different allotropes of MnO2, fabricated with a variety of methods, are assembled into electrodes, playing the role of cathode or oxygen reduction reaction (ORR) electrocatalyst. Often, MnO2-based cathodes are combined with Zn anodes into different types of batteries, resulting in contact between MnO2 and its electrochemical reaction products, and Zn2+. Awareness is growing that this interaction adversely affects the functional performance of MnO2, but no definitive understanding has been reached for this issue. This study contributes, through electrochemical measurements accompanied by microscopy and Raman spectroscopy, to a better understanding of the way the electrochemical behavior of two technologically representative types of manganese dioxide - hydrothermally grown α-MnO2 and electrodeposited γ-MnO2 (EDM) - is degraded when these materials are exposed to neutral and alkaline aqueous solutions, containing Zn2+. Specifically, we highlighted different types of irreversible changes in electrochemical response, which can be interpreted with phase-formation processes. Such changes result in the deactivation of α-MnO2 as ORR electrocatalyst, and of both α-MnO2 and EDM as zinc-ion battery (ZIB) cathodes. The electroactivity of EDM for ZIB operation can be restored if Mn2+ is added to the neutral electrolyte, because a phase, active in discharge, is electrodeposited during charging

Insight into the Cycling Behaviour of Metal Anodes, Enabled by X-ray Tomography and Mathematical Modelling

This work tackles the methodological challenge of rationalizing symmetric-cell cycling data from a materials-science perspective, through experiment replication, mathematical modelling, and tomographic imaging. Specifically, we address Zn electrode cycling in alkaline electrolyte with and without adding tetrabutylammonium bromide (TBAB). This additive is known from literature, but its practical impact is jeopardized by lack of in-depth understanding of its behaviour. Electrochemical testing was carried out at practically relevant current densities and the effect of variations of operating conditions was taken into account. The physical chemistry underlying cell potential profiles, has been modelled mathematically, accounting for: electrokinetics, mass-transport, electrode shape change and passivation. In particular, we disclosed an unexpected joint effect of TBAB and current density on passivation time: tomography allowed to rationalise this behaviour in terms of precipitate morphology

Danneggiamento per pitting di acciai bonificati, cementati e nitrurati

La comprensione dei meccanismi di danneggiamento che portano al manifestarsi dell’usura per faticaè di fondamentale importanza per l’ottimizzazione dei materiali e dei trattamenti termici.Il presente lavoro ha previsto l’esecuzione di prove di rotazione disco su disco (rolling disc-on-disc test).Questo metodo si basa sulla rotazione simultanea di una coppia di dischi sagomati in modo da simulareil contatto tra superfici sferiche. Le prove sono state eseguite su tre differenti tipi di acciaio:• UNI EN 42CrMo4 bonificato; • UNI EN 18NiCrMo5 cementato; • UNI EN 42CrMo4 nitruratoLo scopo del presente lavoro è quello di identificare i meccanismi di danneggiamento coinvoltinella fase di innesco del fenomeno di usura per fatica e durante la sua evoluzione.A tal proposito sui campioni ottenuti dalle prove di rotazione disco su disco sono state condotte numerose analisifrattografiche sia ad occhio nudo, che mediante l’utilizzo del microscopio elettronico a scansione (SEM).Sono stati identificati differenti meccanismi di danneggiamento a seconda del tipo di acciaio:• UNI EN 42CrMo4 bonificato: pitting dovuto a cricche originate negli strati superficialifortemente incruditi. • UNI EN 18NiCrMo5 cementato: pitting originato dagli ossidi depositati a bordo granodurante la fase di carburazione. • UNI EN 42CrMo4 nitrurato: pitting dovuto a cricche che siinnescano e propagano all’interno della coltre bianca

Extrinsic modulation of integrin α6 and progenitor cell behavior in mesenchymal stem cells

Mesenchymal stem cells (MSC) are heterogeneous cells of complex nature that show different potentials while different culture conditions can modify their functionalities through interactions with the microenviroment. Here, we found that bone marrow (BM) MSC from different donor sources and passages that expressed higher levels of α6 integrin subunit (ITGA6), showed higher clonogenicity, migration and differentiation potential. ITGA6 showed important roles improving these potentials and regulating proliferation through protein kinase B (AKT) pathway and cell cycle inhibitor proteins p53 and p21. Moreover, ITGA6 downregulation impaired migration. Cell confluence regulated ITGA6, increasing its expression in low density cultures and decreasing in high density cultures. Besides, ITGA6- cells expressed ITGA6 when seeded at low densities. We found higher ITGA6 expression on fibronectin substrates at lower confluency. Fibronectin increased proliferation, clonogenicity, activation of AKT, decreased cell cycle inhibitor proteins and augmented growth factors expression. Spheres-derived MSC showed higher ITGA6 expression and enhanced potentials for migration, clonogenicity and proliferation. In conclusion, though there is an intrinsic regulation of ITGA6 expression, associated to the progenitor potential of BM-MSC, this expression is regulated by culture conditions and is translated in changes in cell behavior and proliferation. This knowledge could be used to enhance the potential of BM-MSC for clinical application

FORENSIC ENGINEERING SURVEYS WITH UAV PHOTOGRAMMETRY AND LASER SCANNING TECHNIQUES

This work aims at presenting the use of new technologies in the field of forensic engineering. In particular, the use of UAV photogrammetry and laser scanning is compared with the traditional methods of surveying an accident site. In this framework, surveys must be carried out promptly, executed in a short time and performed so that the greatest possible amount of information is collected with sufficient accuracy to avoid the possibility of neglecting details once that the scene is no longer preserved. The combination of modern surveying techniques such UAV photogrammetry and laser scanning can properly fulfill these requirements. An experimental test has been arranged and instruments, procedures, settings, practical limits and results have been evaluated and compared with respect to the usual way of performing the survey for forensic purposes. In particular, both qualitative and quantitative considerations are given, assessing the completeness of the reconstructed model, the statistical evaluation of the errors and the accuracy achieved

Novel association of high C-reactive protein levels and A69S at risk alleles in wet age-related macular degeneration women

Purpose: To explore the relationship between plasma C-reactive protein (CRP) levels, the main ARMS2 gene single nucleotide polymorphism (SNP), and gender in patients with neovascular age-related macular degeneration (wet AMD). Methods: Our study included 131 patients with wetAMD [age-related eye disease study (AREDS) category 4] and 153 control participants (AREDS category 1) from two Spanish retinal units. CRP levels were determined on blood samples by high-sensitivity ELISA assay. According to their CRP level, subjects were categorized into three well-established CRP categories: low (3.00 mg/L, H-CRP). Genomic DNA was extracted from oral swabs using QIAcube (Qiagen, Hilden, Germany) and the A69S; rs10490924 of ARMS2 gene was genotyped by allelic discrimination with validated TaqMan assays (Applied Biosystems, Foster City, CA, USA). Univariate and multivariate logistic regression adjusted for age was used to analyze the genomic frequencies and to calculate odds ratio (OR) using SNPStats software. Results: Considering CRP risk categories, H-CRP group showed a significant [OR 4.0 (1.9-8.3)] association with wetAMD compared to L-CRP group. The risk genotypes of A69S (TT) SNPs showed an association with wetAMD risk [OR 14.0 (4.8-40.8)]. Interestingly, the gender stratification of the CRP categories showed a significant increase in CRP levels in wetAMD women compared with control women [OR 6.9 (2.2-22.3)] and with wetAMD men [OR 4.6 (1.3-16.9)]. In addition, the subgroup analysis of CRP within A69S genotype and gender showed a link in women between the A69S and CRP levels in the AMD group compared to controls [OR 4.2 (1.4-12.6)]. Conclusion: Our study shows, for the first time, that a different genetic association related with gender could contribute to AMD risk. As a consequence, the risk of female gender in the different CRP levels and A69S SNP frequencies could be taken into consideration to the established risk relationship of high levels of CRP and its association with risk A69S genotype

Qualidade sanitária e fisiológica de sementes de abóbora variedade menina Brasileira.

O trabalho teve como objetivos avaliar e correlacionar a qualidade sanitária e fisiológica de sementes de abóbora, variedade Menina Brasileira (Cucurbita moschata.). Foram avaliados dois lotes de sementes de abóbora produzidas no sistema agroecológico e quatro no sistema convencional, com e sem tratamento químico. Os lotes foram submetidos aos testes de sanidade, seguindo a metodologia do “Blotter test”, com congelamento, germinação e vigor (primeira contagem, índice de velocidade de germinação, envelhecimento acelerado e emergência de plântulas). Os resultados indicaram a separação dos lotes de diferentes origens a partir da qualidade sanitária e fisiológica, onde as maiores incidências de fungos foram observadas nos lotes agroecológicos e o maior potencial fisiológico foi observado nos lotes de origem convencional não tratados. Foram encontrados os fungos Fusarium oxysporum, Alternaria alternata, Cladosporium cucumerinum, Aspergillus niger, Penicillium digitatum, Rhizopus stolonifer e Phoma terrestris. A qualidade sanitária não interferiu na qualidade fisiológica das sementes de abóbora, variedade Menina Brasileira

Endothelial alpha-parvin controls integrity of developing vasculature and is required for maintenance of cell-cell junctions

RATIONALE: Angiogenesis and vessel integrity depend on the adhesion of endothelial cells (EC) to the extracellular matrix (ECM) and to adjacent ECs. The focal adhesion protein alpha-parvin (alpha-pv) is essential for vascular development. However, the role of alpha-pv in ECs in vivo is not known. OBJECTIVE: To determine the function of alpha-pv in ECs during vascular development in vivo and the underlying mechanisms. METHODS AND RESULTS: We deleted the alpha-pv gene specifically in ECs of mice to study its role in angiogenesis and vascular development. Here we show that endothelial-specific deletion of alpha-pv in mice results in late embryonic lethality associated with hemorrhages and reduced vascular density. Postnatal induced EC-specific deletion of alpha-pv leads to retinal hypovascularization due to reduced vessel sprouting and excessive vessel regression. In the absence of alpha-pv, blood vessels display impaired VE-cadherin junction morphology. In vitro, alpha-pv deficient ECs show reduced stable adherens junctions, decreased monolayer formation and impaired motility, associated with reduced formation of integrin-mediated cell-ECM adhesion structures and an altered actin cytoskeleton. CONCLUSIONS: Endothelial alpha-pv is essential for vessel sprouting and for vessel stability