Nanometer-thick passive films on metals usually impart remarkable resistance to general corrosion but are susceptible to localized attack in certain aggressive media, leading to material failure with ...pronounced adverse economic and safety consequences. Over the past decades, several classic theories have been proposed and accepted, based on hypotheses and theoretical models, and oftentimes, not sufficiently nor directly corroborated by experimental evidence. Here we show experimental results on the structure of the passive film formed on a FeCr
Ni
single crystal in chloride-free and chloride-containing media. We use aberration-corrected transmission electron microscopy to directly capture the chloride ion accumulation at the metal/film interface, lattice expansion on the metal side, undulations at the interface, and structural inhomogeneity on the film side, most of which had previously been rejected by existing models. This work unmasks, at the atomic scale, the mechanism of chloride-induced passivity breakdown that is known to occur in various metallic materials.
Supplementary cementitious materials (SCMs) like fly ash (FA) and blast furnace slag (BFS) are normally used to replace parts of Ordinary Portland cement (OPC) to reduce the cost and CO2 emission. ...During the carbonation, a relatively high amount of C-S-H with low Ca/Si ratio will be carbonated in cement paste blended with SCMs. Therefore, it’s very important to figure out the influences of the carbonation of C-S-H on the pore structure of SCMs blended cement paste.
In this paper, Mercury Intrusion Porosimetry (MIP) are used to determine the pore volume and size distribution of capillary pores. Results reveal that carbonation of most of the species of C-S-H results in increased porosity of cement paste. Total and effective capillary porosity of pastes blended with high amount of BFS increase after carbonation. This will bring adverse effects on the durability of blended cement concrete exposed to the carbonation.
Autism is a prevailing neurodevelopmental disorder with a large genetic/genomic component. Recently, the dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1 A (DYRK1A) gene was ...implicated as a risk factor for autism spectrum disorder (ASD). We identified five DYRK1A variants in ASD patients and found that the dose of DYRK1A protein has a crucial role in various aspects of postnatal neural development. Dyrk1a loss of function and gain of function led to defects in dendritic growth, dendritic spine development and radial migration during cortical development. Importantly, two autism-associated truncations, R205X and E239X, were shown to be Dyrk1a loss-of-function mutants. Studies of the truncated Dyrk1a mutants may provide new insights into the role of Dyrk1a in brain development, as well as the role of Dyrk1a loss of function in the pathophysiology of autism.
Nanometer-thick passive films, which impart superior corrosion resistance to metals, are degraded in long-term service; they are also susceptible to chloride-induced localized attack. Here we show, ...by engineering crystallographic configurations upon metal matrices adjacent to their passive films, we obtain great enhancement of corrosion resistance of FeCr15Ni15 single crystal in sulphuric acid, with activation time up to two orders of magnitude longer than that of the non-engineered counterparts. Meanwhile, engineering crystallography decreases the passive current density and shifts the pitting potential to noble values. Applying anodic polarizations under a transpassivation potential, we make the metal matrices underneath the transpassive films highly uneven with {111}-terminated configurations, which is responsible for the enhancement of corrosion resistance. The transpassivation strategy also works in the commercial stainless steels where both grain interior and grain boundaries are rebuilt into the low-energy configurations. Our results demonstrate a technological implication in the pretreatment process of anti-corrosion engineering.
Tooth development and regeneration are regulated through a complex signaling network. Previous studies have focused on the exploration of intracellular signaling regulatory networks, but the ...regulatory roles of extracellular networks have only been revealed recently. Proteoglycans, which are essential components of the extracellular matrix (ECM) and pivotal signaling molecules, are extensively involved in the process of odontogenesis. Proteoglycans are composed of core proteins and covalently attached glycosaminoglycan chains (GAGs). The core proteins exhibit spatiotemporal expression patterns during odontogenesis and are pivotal for dental tissue formation and periodontium development. Knockout of core protein genes Biglycan, Decorin, Perlecan, and Fibromodulin has been shown to result in structural defects in enamel and dentin mineralization. They are also closely involved in the development and homeostasis of periodontium by regulating signaling transduction. As the functional component of proteoglycans, GAGs are negatively charged unbranched polysaccharides that consist of repeating disaccharides with various sulfation groups; they provide binding sites for cytokines and growth factors in regulating various cellular processes. In mice, GAG deficiency in dental epithelium leads to the reinitiation of tooth germ development and the formation of supernumerary incisors. Furthermore, GAGs are critical for the differentiation of dental stem cells. Inhibition of GAGs assembly hinders the differentiation of ameloblasts and odontoblasts. In summary, core proteins and GAGs are expressed distinctly and exert different functions at various stages of odontogenesis. Given their unique contributions in odontogenesis, this review summarizes the roles of proteoglycans and GAGs throughout the process of odontogenesis to provide a comprehensive understanding of tooth development.
A topological meron features a non-coplanar structure, whose order parameters in the core region are perpendicular to those near the perimeter. A meron is half of a skyrmion, and both have potential ...applications for information carrying and storage. Although merons and skyrmions in ferromagnetic materials can be readily obtained via inter-spin interactions, their behaviour and even existence in ferroelectric materials are still elusive. Here we observe using electron microscopy not only the atomic morphology of merons with a topological charge of 1/2, but also a periodic meron lattice in ultrathin PbTiO
films under tensile epitaxial strain on a SmScO
substrate. Phase-field simulations rationalize the formation of merons for which an epitaxial strain, as a single alterable parameter, plays a critical role in the coupling of lattice and charge. This study suggests that by engineering strain at the nanoscale it should be possible to fabricate topological polar textures, which in turn could facilitate the development of nanoscale ferroelectric devices.
As the life expectancy and growth of the aging population increase globally, efforts to promote healthy longevity become more important. Holistic policy guidelines and actions have been designed to ...advocate and fortify healthy aging at multiple levels. Oral health, a fundamental contributor of overall health and well-being, forms a core part of the noncommunicable disease agenda within the sustainable development goals set by the World Health Organization. Aging significantly heightens the risk of myriad oral disorders and other noncommunicable diseases. As of 2019, oral disorders accounted for 8.9 million disability-adjusted life-years in individuals older than 60 y. In addition to the development of multidisciplinary aging-friendly policies to promote healthy aging, basic biology and translational research has been encouraged that focuses on deciphering the underlying mechanisms involved in age-related physical and cognitive decline or dysregulation of oral tissues. Given the relevance of oral health aging as a critical component of the One Health Initiative, this special issue encompasses a collection of articles dedicated to recent advances in the behavioral and social implications of age-related oral diseases and tooth loss on several aspects of the quality of life of adults as they age. Furthermore, it includes articles detailing molecular mechanisms associated with cellular aging and their implications for oral tissue health, periodontal disease severity, and the regenerative potential of stem cells.
Context.
Despite over 50 years of research, many open questions remain about the origin and nature of gamma-ray bursts (GRBs). Linear polarization measurements of the prompt emission of these extreme ...phenomena have long been thought to be key to answering a range of these questions. The POLAR detector was designed to produce the first set of detailed and reliable linear polarization measurements in the 50 − 500 keV energy range. During late 2016 and early 2017, POLAR detected a total of 55 GRBs. The analysis results of 5 of these GRBs have been reported, and were found to be consistent with a low or unpolarized flux. However, previous reports by other collaborations found high levels of linear polarization, including some as high as 90%.
Aims.
We study the linear polarization for the 14 GRBs observed by POLAR for which statistically robust inferences are possible. Additionally, time-resolved polarization studies are performed on GRBs with sufficient apparent flux.
Methods.
A publicly available polarization analysis tool, developed within the Multi-Mission Maximum Likelihood framework (
3ML
), was used to produce statistically robust results. The method allows spectral and polarimetric data from POLAR to be combined with spectral data from the
Fermi
Gamma-ray Burst Monitor (
Fermi
-GBM) and the
Neil Gehrels Swift
Observatory to jointly model the spectral and polarimetric parameters.
Results.
The time-integrated analysis finds all results to be compatible with low or zero polarization with the caveat that, when time-resolved analysis is possible within individual pulses, we observe moderate linear polarization with a rapidly changing polarization angle. Therefore, time-integrated polarization results, while pointing to lower polarization, are potentially an artifact of summing over the changing polarization signal and thus washing out the true moderate polarization. We therefore caution against overinterpretation of any time-integrated results inferred herein and encourage the community to wait for more detailed polarization measurements from forthcoming missions such as POLAR-2 and LEAP.
This document is an essential companion to the third iteration of the National Academy of Clinical Biochemistry NACB,
now the American Association for Clinical Chemistry (AACC) Academy Laboratory ...Medicine Practice Guidelines (LMPG) on cardiac markers. The expert consensus recommendations were drafted in collaboration with the International Federation of Clinical Chemistry and Laboratory Medicine Task Force on Clinical Applications of Bio-Markers (IFCC TF-CB). We determined that there is sufficient clinical guidance on the use of cardiac troponin (cTn) testing from clinical practice groups. Thus, in this expert consensus document, we focused on clinical laboratory practice recommendations for high-sensitivity (hs)-cTn assays. This document utilized the expert opinion class of evidence to focus on the following 10 topics: (
) quality control (QC) utilization, (
) validation of the lower reportable analytical limits, (
) units to be used in reporting measurable concentrations for patients and QC materials, (
) 99th percentile sex-specific upper reference limits to define the reference interval; (
) criteria required to define hs-cTn assays, (
) communication with clinicians and the laboratory's role in educating clinicians regarding the influence of preanalytic and analytic problems that can confound assay results, (
) studies on hs-cTn assays and how authors need to document preanalytical and analytical variables, (
) harmonizing and standardizing assay results and the role of commutable materials, (
) time to reporting of results from sample receipt and sample collection, and (
) changes in hs-cTn concentrations over time and the role of both analytical and biological variabilities in interpreting results of serial blood collections.
A high-fat diet (HFD) is a major risk factor for cardiovascular diseases. Many pure compounds have been demonstrated to be effective in treating cardiovascular diseases. In this study, we ...investigated the alleviating effects of oral ovatodiolide and antcin K (OAK) supplements on HFD-induced cardiovascular dysfunction in apolipoprotein E (ApoE)-knockout mice. Cardiovascular dysfunction was induced in ApoE-knockout mice by feeding them an HFD for 12 weeks. The degree of cardiovascular dysfunction was assessed through echocardiography, hematological and biochemical analyses, and immunofluorescence and immunohistochemical staining. The HFD-fed mice exhibited cardiovascular dysfunction—abnormal blood biochemical index. The arterial wall tissue exhibited the marked deposition of lipids, upregulated expression of vascular cell adhesion molecule-1 and CD36 receptors, and downregulated expression of the ABCA1 receptor. Macrophages isolated from the peritoneal cavity of the mice exhibited increased levels of lipid accumulation, reactive oxygen species, and CD11b expression but reduced mitochondrial membrane potential. The expression of superoxide dismutase 2 was downregulated and that of tumor necrosis factor-α was upregulated in the myocardial tissue. Oral OAK supplements twice a day for 12 weeks significantly mitigated HFD-induced cardiovascular dysfunction in the experimental mice. Oral OAK supplements appear to be a promising strategy for treating HFD-induced cardiovascular dysfunction. The underlying mechanisms may involve the reduction of lipid accumulation in the artery and oxidative stress and inflammation in the cardiovascular tissue.
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