Young infants exhibit robust functional antibody responses and restrained IFN-γ production to SARS-CoV-2

Severe COVID-19 appears rare in children. This is unexpected, especially in young infants, who are vulnerable to severe disease caused by other respiratory viruses. We evaluate convalescent immune responses in four infants under 3 months old with confirmed COVID-19 who presented with mild febrile illness, alongside their parents, and adult controls recovered from confirmed COVID-19. Although not statistically significant, compared to seropositive adults, infants have high serum levels of IgG and IgA to SARS-CoV-2 spike protein with corresponding functional ability to block SARS-CoV-2 cellular entry. Infants also exhibit robust saliva anti-spike IgG and IgA responses. Spike-specific IFN-γ production by infant peripheral blood mononuclear cells appears restrained, but the frequency of spike-specific IFN-γ and/or TNF-ɑ producing T cells is comparable between infants and adults. On principal component analysis, infant immune responses appear distinct from their parents. Robust functional antibody responses alongside restrained IFN-γ production may help protect infants from severe COVID-19

Development and evaluation of low-volume tests to detect and characterize antibodies to SARS-CoV-2

Low-volume antibody assays can be used to track SARS-CoV-2 infection rates in settings where active testing for virus is limited and remote sampling is optimal. We developed 12 ELISAs detecting total or antibody isotypes to SARS-CoV-2 nucleocapsid, spike protein or its receptor binding domain (RBD), 3 anti-RBD isotype specific luciferase immunoprecipitation system (LIPS) assays and a novel Spike-RBD bridging LIPS total-antibody assay. We utilized pre-pandemic (n=984) and confirmed/suspected recent COVID-19 sera taken pre-vaccination rollout in 2020 (n=269). Assays measuring total antibody discriminated best between pre-pandemic and COVID-19 sera and were selected for diagnostic evaluation. In the blind evaluation, two of these assays (Spike Pan ELISA and Spike-RBD Bridging LIPS assay) demonstrated >97% specificity and >92% sensitivity for samples from COVID-19 patients taken >21 days post symptom onset or PCR test. These assays offered better sensitivity for the detection of COVID-19 cases than a commercial assay which requires 100-fold larger serum volumes. This study demonstrates that low-volume in-house antibody assays can provide good diagnostic performance, and highlights the importance of using well-characterized samples and controls for all stages of assay development and evaluation. These cost-effective assays may be particularly useful for seroprevalence studies in low and middle-income countries

Delineamentos para uma teoria da Museologia

The guiding principles in the formulation of a Museology theory were established\ud and disseminated internationally from the mid-1980s, and are related to the creation of the\ud International Committee for Museology (Icofom), associated with the International Council of\ud Museums (Icom). The opinions regarding the nature of so-called museological knowledge\ud were issued under the very specific conditions of each groups composition and of the intellectual\ud work undertook in the occasion. Despite the difficulties with the wording, risen in tandem with\ud the exercise (the terminology problem), we focused on the conjuncture that surrounded the\ud formulation: the environment, the aims, the way in which it was composed and the foundations\ud that characterise it, as well as some of the discussions that took place, which revealed aspects\ud that have been handed down as a legacy in this field of specialization

The influence of temperature and pore size on cell growth and proliferation on hydroxyapatite scaffolds

Porous biomaterials, especially synthetic porous ceramics, are of significant importance in bone tissue engineering, and there has been rapid growth in the medical use of these biomaterials over the last 50 years. The reason is that they are relatively easy to prepare and are available in unlimited supply, unlike the allografts and autografts that are used in clinical practice. Various hydroxyapatite (HAp) scaffolds can be prepared, using various pore-forming techniques and firing temperatures. The firing temperature significantly affects microstructural parameters such as total porosity, pore size, the interconnected pore network, and also the chemical and phase composition. Last but not least, it also affects the mechanical properties of the samples. Knowledge about these factors is therefore essential for designing a sample with the desired controlled microstructure and properties. In this work, uniaxial pressing has been used for preparing HAp disks from nanocrystalline HAp powder, using saccharose as a pore-forming agent. The highest porosity achieved (after partial sintering at 800°C) was in the range of 64.7-70.6%. The firing temperature significantly affects porosity, pore size, grain size and mechanical strength, whereas the dwell time has only a minor effect on these parameters. After firing, XRD confirmed more than 98.4% HAp in all cases. Mercury porosimetry confirmed the presence of nanosized interstitial voids for partially sintered materials and pore throat sizes of approximately 100μm (much smaller than the pore cavities), which is adequate for bone cell penetration and further ingrowth. After firing at 1200°C, the matrix is more or less fully sintered, and nanosized pores are absent or closed. The biological part of the paper summarizes the results from cell-seeding and cultivation experiments to determine the cell adhesion, proliferation, viability, mitochondrial activity and osteogenic cell differentiation on the scaffolds, and thus the biocompatibility and bioactivity of the scaffolds. The highest values for all these parameters, particularly the number of cells, were on HAp fired at 1200°C. The samples fired at 1200°C were prepared with various pore sizes (in the range of 100 - 800μm). We found that pore size has a non-significant effect on cell colonization, whereas the firing temperature has a major influence. All tested HAp samples showed a remarkable ability to adsorb proteins on their surfaces, namely albumin and fibronectin, and to promote cell adhesion. Some cytotoxic activity was observed on the samples fired at 800 and 1000°C. Possible reasons for this cytotoxicity have been discussed. However, it can be concluded that the HAp samples created in this study and fired at 1200°C hold great promise for bone tissue engineering

Thermal conductivity of porous alumina ceramics prepared using starch as a pore-forming agent

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