70 research outputs found
Accelerating the Discovery of g-CN-Supported Single Atom Catalysts for Hydrogen Evolution Reaction: A Combined DFT and Machine Learning Strategy
Two-dimensional materials supported by single atom catalysis (SACs) are
foreseen to replace platinum for large-scale industrial scalability of
sustainable hydrogen generation. Here, a series of metal (Al, Sc, Ti, V, Cr,
Mn, Fe, Ni, Cu, Zn) and non-metal (B, C, N, O, F, Si, P, S, Cl) single atoms
embedded on various active sites of g-CN are screened by DFT
calculations and six machine learning (ML) algorithms (support vector
regression, gradient boosting regression, random forest regression, AdaBoost
regression, multilayer perceptron regression, ridge regression). Our results
based on formation energy, Gibbs free energy and bandgap analysis demonstrate
that the single atoms of B, Mn and Co anchored on g-CN can serve as
highly efficient active sites for hydrogen production. The ML model based on
support vector regression (SVR) exhibits the best performance to accurately and
rapidly predict the Gibbs free energy of hydrogen adsorption (GH )
for the test set with a lower mean absolute error (MAE) and a high coefficient
of determination (R) of 0.45 and 0.81, respectively. Feature selection
based on the SVR model highlights the top five primary features: formation
energy, bond length, boiling point, melting point, and valance electron as key
descriptors. Overall, the multistep work-flow employed through DFT calculations
combined with ML models for efficient screening of potential hydrogen evolution
reaction (HER) from g-CN-based single atom catalysis can significantly
contribute to the catalyst design and fabrication.Comment: 10 pages, 4 figure
Modulation of T cell cytokine profiles and peptide-MHC complex availability in vivo by delivery to scavenger receptors via antigen maleylation
We have previously shown that conversion of proteins to scavenger receptor (SR) ligands by maleylation increases their immunogenicity. We now show that maleyl-Ag-immune spleen cells make relatively more IFN-ϒ and less IL-4 or IL-10 than native Ag-immune cells. This is also reflected in the IgG1:IgG2a ratios in Abs generated in vivo. SR engagement on macrophages does not alter their surface levels of the adhesive/costimulatory molecules CD11a/CD18, CD11b/CD18, CD24, CD54, or CD40, nor does it enhance their ability to support anti-CD3-driven proliferation of naive T cells in vitro. Costimulatory molecules implicated in differential Th1/Th2 commitment-CD80, CD86, and IL-12-are not inducible by SR ligation. In addition to macrophages and dendritic cells, B cells also show receptor-mediated uptake and enhanced presentation of maleyl-Ags. Using a monoclonal T cell line to detect peptide-MHC complexes expressed on spleen cells in Ag-injected mice, we find that higher levels of these complexes are generated in vivo from maleyl-proteins and they persist longer than those generated from the native protein. Together, these data suggest that in certain situations, the levels of cognate ligand available and/or the time course of their availability may play a major role in determining the cytokine profiles of the responding T cells in addition to the costimulatory signals implicated so far
Management of dental avulsion injuries: a survey of dental support staff in Cairns, Australia
The aim of this study was to assess the knowledge of dental support staff in providing appropriate first-aid advice regarding dental avulsion emergencies. Methods: This study was reported according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for cross-sectional studies. Dental support staff (includes dental assistants, administrative staff and other non-clinical staff) were contacted and data were collected from 50 private dental clinics across the Greater Cairns Area, Queensland, Australia. These data were collected through an online survey throughout 2020. Descriptive statistics and Pearson’s Chi-squared test was used to analyze the data and any associations between categorical outcomes. Results: This survey yielded a response rate of 34.1% with a margin of error of 10.3%. More than four-tenths of participants (42%) reported that they had received some form of dental avulsion management training previously. All but five participants (92%) denoted that they would immediately replant an avulsed permanent tooth. More than half of all participants would choose to rinse a soiled avulsed tooth with fresh milk (55%) and transport that tooth in fresh milk (65%) should they not be able to replant the tooth at the site. Almost nine in every ten participants (85%) expressed willingness to further their training in this area. Knowledge in replanting avulsed permanent teeth was found to be significantly impacted by gender, age, years of experience and participation in formal avulsion training. Male participants were found to be significantly more likely (p = 0.025) to replant a permanent avulsed tooth than their female counterparts. Participants who were 40 years of age and above were found to be significantly more likely to choose fresh milk to transport avulsed teeth (p = 0.0478). Older participants (p = 0.0021), alongside those who had greater years of experience (p = 0.0112) and those who had undertaken formal avulsion training (p = 0.0106) were all significantly more likely to express greater confidence in their ability to manage dental avulsion injuries. Participants who had previously received some form of education regarding avulsion injury management were also most likely to warrant further education and training in this area (p < 0.0001). Conclusion: This study demonstrated that dental support staff in the Greater Cairns Area seem to have a fair grasp of first-aid knowledge regarding the management of dental avulsion injuries. This result indicates that this knowledge has been picked up through years of experience, rather than a formal education. Despite this, one would expect people who work in the dental industry to be able to provide accurate and appropriate assistance during dental emergencies, hence, further training is warranted to ensure optimum patient outcomes
A Systematic Review on Predisposition to Lymphoid (B and T cell) Neoplasias in Patients With Primary Immunodeficiencies and Immune Dysregulatory Disorders (Inborn Errors of Immunity)
Primary immunodeficiencies and immune dysregulatory disorders (PIDDs; now referred to as inborn errors in immunity) are rare disorders with a prevalence of 41. 4 or 50.5 per 100,000 persons (1). The incidence of malignancy in PIDD patents is the second-highest cause of death in children as well as adults, after infection, and is higher in certain PIDDs compared to others. We performed a systematic review of the literature to identify reports of B cell and T cell neoplasias in PIDDs and clustered them based on their classification in the IUIS schema. As would be expected, higher susceptibility to malignancies are typically reported in patients with Common Variable Immunodeficiency (CVID), combined immunodeficiencies affecting cellular immunity, in particular, DNA repair defects, or in the context of impaired immune regulatory control. There is not much evidence of increased risk for cancer in patients with innate immune defects, indicating that not all types of infection or genetic susceptibility predispose equally to cancer risk. Viral infections, in particular EBV, HHV and HPV, have been shown to increase susceptibility to developing cancer, but also patients with defects in immune regulation, such as Autoimmune Lymphoproliferative Syndrome (ALPS), activated p110delta syndrome (APDS type 1) and IL-10 receptor deficiency among others have a higher incidence of neoplastic disease, particularly lymphomas. In fact, lymphomas account for two-thirds of all malignancies reported in PIDD patients (2), with either a combined immunodeficiency or DNA repair defect predominating as the underlying immune defect in one registry, or antibody deficiencies in another (3). The vast majority of lymphomas reported in the context of PIDDs are B cell lymphomas, though T cell lymphomas have been reported in a few studies, and tend to largely be associated with chromosomal breakage disorders (4) or Cartilage Hair Hypoplasia (5). There appears to be a much higher prevalence of T cell lymphomas in patients with secondary immunodeficiencies (6), though this could reflect treatment bias. We reviewed the literature and summarized the reports of B and T cell lymphoma in PIDD patients to survey the current state of knowledge in this area
Immunoglobulin variable-region gene mutational lineage tree analysis: application to autoimmune diseases
Lineage trees have frequently been drawn to illustrate diversification, via somatic hypermutation (SHM), of immunoglobulin variable-region (IGV) genes. In order to extract more information from IGV sequences, we developed a novel mathematical method for analyzing the graphical properties of IgV gene lineage trees, allowing quantification of the differences between the dynamics of SHM and antigen-driven selection in different lymphoid tissues, species, and disease situations. Here, we investigated trees generated from published IGV sequence data from B cell clones participating in autoimmune responses in patients with Myasthenia Gravis (MG), Rheumatoid Arthritis (RA), and Sjögren's Syndrome (SS). At present, as no standards exist for cell sampling and sequence extraction methods, data obtained by different research groups from two studies of the same disease often vary considerably. Nevertheless, based on comparisons of data groups within individual studies, we show here that lineage trees from different individual patients are often similar and can be grouped together, as can trees from two different tissues in the same patient, and even from IgG- and IgA-expressing B cell clones. Additionally, lineage trees from most studies reflect the chronic character of autoimmune diseases
Receptors via Antigen Maleylation In Vivo by Delivery to Scavenger and Peptide-MHC Complex Availability Modulation of T Cell Cytokine Profiles
MYSM1 attenuates DNA damage signals triggered by physiologic and genotoxic DNA breaks
BACKGROUND: Patients with deleterious variants in MYSM1 have an immune deficiency characterized by B-cell lymphopenia, hypogammaglobulinemia, and increased radiosensitivity. MYSM1 is a histone deubiquitinase with established activity in regulating gene expression. MYSM1 also localizes to sites of DNA injury but its function in cellular responses to DNA breaks has not been elucidated.
OBJECTIVES: This study sought to determine the activity of MYSM1 in regulating DNA damage responses (DDRs) to DNA double-stranded breaks (DSBs) generated during immunoglobulin receptor gene (Ig) recombination and by ionizing radiation.
METHODS: MYSM1-deficient pre- and non-B cells were used to determine the role of MYSM1 in DSB generation, DSB repair, and termination of DDRs.
RESULTS: Genetic testing in a newborn with abnormal screen for severe combined immune deficiency, T-cell lymphopenia, and near absence of B cells identified a novel splice variant in MYSM1 that results in nearly absent protein expression. Radiosensitivity testing in patient\u27s peripheral blood lymphocytes showed constitutive γH2AX, a marker of DNA damage, in B cells in the absence of irradiation, suggesting a role for MYSM1 in response to DSBs generated during Ig recombination. Suppression of MYSM1 in pre-B cells did not alter generation or repair of Ig DSBs. Rather, loss of MYSM1 resulted in persistent DNA damage foci and prolonged DDR signaling. Loss of MYSM1 also led to protracted DDRs in U2OS cells with irradiation induced DSBs.
CONCLUSIONS: MYSM1 regulates termination of DNA damage responses but does not function in DNA break generation and repair
Evaluation and Management of Deficiency of Adenosine Deaminase 2: An International Consensus Statement
IMPORTANCE: Deficiency of adenosine deaminase 2 (DADA2) is a recessively inherited disease characterized by systemic vasculitis, early-onset stroke, bone marrow failure, and/or immunodeficiency affecting both children and adults. DADA2 is among the more common monogenic autoinflammatory diseases, with an estimate of more than 35 000 cases worldwide, but currently, there are no guidelines for diagnostic evaluation or management. OBJECTIVE: To review the available evidence and develop multidisciplinary consensus statements for the evaluation and management of DADA2. EVIDENCE REVIEW: The DADA2 Consensus Committee developed research questions based on data collected from the International Meetings on DADA2 organized by the DADA2 Foundation in 2016, 2018, and 2020. A comprehensive literature review was performed for articles published prior to 2022. Thirty-two consensus statements were generated using a modified Delphi process, and evidence was graded using the Oxford Center for Evidence-Based Medicine Levels of Evidence. FINDINGS: The DADA2 Consensus Committee, comprising 3 patient representatives and 35 international experts from 18 countries, developed consensus statements for (1) diagnostic testing, (2) screening, (3) clinical and laboratory evaluation, and (4) management of DADA2 based on disease phenotype. Additional consensus statements related to the evaluation and treatment of individuals with DADA2 who are presymptomatic and carriers were generated. Areas with insufficient evidence were identified, and questions for future research were outlined. CONCLUSIONS AND RELEVANCE: DADA2 is a potentially fatal disease that requires early diagnosis and treatment. By summarizing key evidence and expert opinions, these consensus statements provide a framework to facilitate diagnostic evaluation and management of DADA2
Relevance of laboratory testing for the diagnosis of primary immunodeficiencies: a review of case-based examples of selected immunodeficiencies
The field of primary immunodeficiencies (PIDs) is one of several in the area of clinical immunology that has not been static, but rather has shown exponential growth due to enhanced physician, scientist and patient education and awareness, leading to identification of new diseases, new molecular diagnoses of existing clinical phenotypes, broadening of the spectrum of clinical and phenotypic presentations associated with a single or related gene defects, increased bioinformatics resources, and utilization of advanced diagnostic technology and methodology for disease diagnosis and management resulting in improved outcomes and survival. There are currently over 200 PIDs with at least 170 associated genetic defects identified, with several of these being reported in recent years. The enormous clinical and immunological heterogeneity in the PIDs makes diagnosis challenging, but there is no doubt that early and accurate diagnosis facilitates prompt intervention leading to decreased morbidity and mortality. Diagnosis of PIDs often requires correlation of data obtained from clinical and radiological findings with laboratory immunological analyses and genetic testing. The field of laboratory diagnostic immunology is also rapidly burgeoning, both in terms of novel technologies and applications, and knowledge of human immunology. Over the years, the classification of PIDs has been primarily based on the immunological defect(s) ("immunophenotype") with the relatively recent addition of genotype, though there are clinical classifications as well. There can be substantial overlap in terms of the broad immunophenotype and clinical features between PIDs, and therefore, it is relevant to refine, at a cellular and molecular level, unique immunological defects that allow for a specific and accurate diagnosis. The diagnostic testing armamentarium for PID includes flow cytometry - phenotyping and functional, cellular and molecular assays, protein analysis, and mutation identification by gene sequencing. The complexity and diversity of the laboratory diagnosis of PIDs necessitates many of the above-mentioned tests being performed in highly specialized reference laboratories. Despite these restrictions, there remains an urgent need for improved standardization and optimization of phenotypic and functional flow cytometry and protein-specific assays. A key component in the interpretation of immunological assays is the comparison of patient data to that obtained in a statistically-robust manner from age and gender-matched healthy donors. This review highlights a few of the laboratory assays available for the diagnostic work-up of broad categories of PIDs, based on immunophenotyping, followed by examples of disease-specific testing
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