ABSTRACT
Owing to the load bearing and the other external environmental factors, the defects in the concrete occur in the form of cracks and flaws which leads to the reduction in the durability characteristics. Generally, the bacteria-based autogenous healing is adopted to restore those cracks. The ureolytic bacteria used urea as a source of nitrogen and convert it to carbonate ions, and then carbonate ions react with calcium ions to induce calcium carbonate in the presence of water. In the present study, binary cement-based concrete containing different concentration of immobilized bacteria is investigated, and its performance is evaluated based on the strength and durability characteristics. The experimentation includes bagasse ash (< 45µ) and fly ash (Class C) in proportions partially blended with cement. External loads are stimulated to assess the mechanical properties of concrete. Rapid chloride penetration test of the concrete before the induction of cracks is also performed. By comparing the compression test results, the microbial concrete of 105cells/mg shows greater compressive strength when compared with the microbial concrete of 107cells/mg and also with the conventional concrete. SEM analysis and compression test results reveal 15% fly ash additives have accomplished microbial concrete. And also the test results indicate the potential of encapsulation using clay pellets and silica gel.
Subject(s)
Calcium Carbonate , Construction Materials , Bacteria , Coal Ash , Compressive Strength , Construction Materials/analysisABSTRACT
We evaluated post-vaccination immunity after COVID-19 vaccination with serial changes in cellular and antibody responses to the spike protein S, its S2 component which is conserved between SARS-CoV-2 and human coronaviruses, and the S1 component, which is specific to SARS-CoV-2 and also contains its receptor binding domain (RBD). In 21 healthy immunocompetent subjects all of whom demonstrated circulating IgG antibodies 4 months after mRNA1273 or BNT162b vaccination, a) the strength of S-IgG was stable while RBD-IgG declined, b) S2-reactive B-cell frequencies increased progressively (p=0.002) c) S1-reactive CD8+T-cells and CD19+B-cells were undetectable after a transient increase, and d) monocytic and polymorphonuclear myeloid-derived suppressor cells (M-MDSC, PMN-MDSC) increased after the first vaccine dose. Compared with 4-month measurements from immunocompetent subjects, single samples from 20 vaccinated immunocompromised (IC) subjects revealed a) circulating S-IgG and RBD-IgG in 13 (65%) and 9 (45%) subjects, respectively, b) no differences in S2-reactive T- and B-cells, c) undetectable S1-reactive T- and B-cells, and d) fewer S-reactive CD8+T-cells and CD19+B-cells (p<0.05). Among 11 IC recipients who failed to make RBD-IgG, frequencies of PMN-MDSC were significantly higher (p<0.0004) compared with IC or immunocompetent subjects with RBD-IgG. COVID-19 vaccination induces stable antibodies to the spike protein and expands circulating B-cells reactive to the conserved spike protein sequence in immunocompetent subjects. MDSC which are known to suppress T- and B-cells, and which increase after vaccination, may limit post-vaccination responses especially among immunocompromised subjects. Antibody and cellular responses to SARS-CoV-2-specific spike antigenic sequences appear to be less durable.
ABSTRACT
Assessment of T-cell immunity to the COVID-19 coronavirus requires reliable assays and is of great interest, given the uncertain longevity of the antibody response. Some recent reports have used immunodominant spike (S) antigenic peptides and anti-CD28 co-stimulation in varying combinations to assess T-cell immunity to SARS-CoV-2. These assays may cause T-cell hyperstimulation and could overestimate antiviral immunity in chronically immunosuppressed transplant recipients, who are predisposed to infections and vaccination failures. Here, we evaluate CD154-expressing T-cells induced by unselected S antigenic peptides in 204 subjects-103 COVID-19 patients and 101 healthy unexposed subjects. Subjects included 72 transplanted and 130 non-transplanted subjects. S-reactive CD154+T-cells co-express and can thus substitute for IFN{gamma} (n=3). Assay reproducibility in a variety of conditions was acceptable with coefficient of variation of 2-10.6%. S-reactive CD154+T-cell frequencies were a) higher in 42 healthy unexposed transplant recipients who were sampled pre-pandemic, compared with 59 healthy non-transplanted subjects (p=0.02), b) lower in Tr COVID-19 patients compared with healthy transplant patients (p<0.0001), c) lower in Tr patients with severe COVID-19 (p<0.0001), or COVID-19 requiring hospitalization (p<0.05), compared with healthy Tr recipients. S-reactive T-cells were not significantly different between the various COVID-19 disease categories in NT recipients. Among transplant recipients with COVID-19, cytomegalovirus co-infection occurred in 34%; further, CMV-specific T-cells (p<0.001) and incidence of anti-receptor-binding-domain IgG (p=0.011) were lower compared with non-transplanted COVID-19 patients. Healthy unexposed transplant recipients exhibit pre-existing T-cell immunity to SARS-CoV-2. COVID-19 infection leads to impaired T-cell and antibody responses to SARS-CoV-2 and increased risk of CMV co-infection in transplant recipients.
ABSTRACT
In the present research work, an effort has been made to explore the potential of using the adhesive tapes while drilling CFRPs. The input parameters, such as drill bit diameter, point angle, Scotch tape layers, spindle speed, and feed rate have been studied in response to thrust force, torque, circularity, diameter error, surface roughness, and delamination occurring during drilling. It has been found that the increase in point angle increased the delamination, while increase in Scotch tape layers reduced delamination. The surface roughness decreased with the increase in drill diameter and point angle, while it increased with the speed, feed rate, and tape layer. The best low roughness was obtained at 6 mm diameter, 130° point angle, 0.11 mm/rev feed rate, and 2250 rpm speed at three layers of Scotch tape. The circularity error initially increased with drill bit diameter and point angle, but then decreased sharply with further increase in the drill bit diameter. Further, the circularity error has non-linear behavior with the speed, feed rate, and tape layer. Low circularity error has been obtained at 4 mm diameter, 118° point angle, 0.1 mm/rev feed rate, and 2500 RPM speed at three layers of Scotch tape. The low diameter error has been obtained at 6 mm diameter, 130° point angle, 0.12 mm/rev feed rate, and 2500 rpm speed at three layer Scotch tape. From the optical micro-graphs of drilled holes, it has been found that the point angle is one of the most effective process parameters that significantly affects the delamination mechanism, followed by Scotch tape layers as compared to other parameters such as drill bit diameter, spindle speed, and feed rate.
ABSTRACT
The development of a portfolio of SARS-CoV-2 vaccines to vaccinate the global population remains an urgent public health imperative. Here, we demonstrate the capacity of a subunit vaccine under clinical development, comprising the SARS-CoV-2 Spike protein receptor binding domain displayed on a two-component protein nanoparticle (RBD-NP), to stimulate robust and durable neutralizing antibody (nAb) responses and protection against SARS-CoV-2 in non-human primates. We evaluated five different adjuvants combined with RBD-NP including Essai O/W 1849101, a squalene-in-water emulsion; AS03, an alpha-tocopherol-containing squalene-based oil-in-water emulsion used in pandemic influenza vaccines; AS37, a TLR-7 agonist adsorbed to Alum; CpG 1018-Alum (CpG-Alum), a TLR-9 agonist formulated in Alum; or Alum, the most widely used adjuvant. All five adjuvants induced substantial nAb and CD4 T cell responses after two consecutive immunizations. Durable nAb responses were evaluated for RBD-NP/AS03 immunization and the live-virus nAb response was durably maintained up to 154 days post-vaccination. AS03, CpG-Alum, AS37 and Alum groups conferred significant protection against SARS-CoV-2 infection in the pharynges, nares and in the bronchoalveolar lavage. The nAb titers were highly correlated with protection against infection. Furthermore, RBD-NP when used in conjunction with AS03 was as potent as the prefusion stabilized Spike immunogen, HexaPro. Taken together, these data highlight the efficacy of the RBD-NP formulated with clinically relevant adjuvants in promoting robust immunity against SARS-CoV-2 in non-human primates.
ABSTRACT
Recently emerged beta-coronavirus, SARS-CoV-2 has resulted in the current pandemic designated COVID-19. COVID-19 manifests as severe illness exhibiting systemic inflammatory response syndrome, acute respiratory distress syndrome (ARDS), thrombotic events, and shock, exacerbated further by co-morbidities and age1-3. Recent clinical reports suggested that the pulmonary failure seen in COVID-19 may not be solely driven by acute ARDS, but also microvascular thrombotic events, likely driven by complement activation4,5. However, it is not fully understood how the SARS-CoV-2 infection mechanisms mediate thrombotic events, and whether such mechanisms and responses are unique to SARS-CoV-2 infection, compared to other respiratory infections. We address these questions here, in the context of normal lung epithelia, in vitro and in vivo, using publicly available data. Our results indicate that plasmin is a crucial mediator which primes interactions between complement and platelet-activating systems in lung epithelia upon SARS-CoV-2 infection, with a potential for therapeutic intervention.
ABSTRACT
We have used a bioinformatics approach for the identification and reconstruction of metabolic pathways associated with amino acid metabolism in human mitochondria. Human mitochondrial proteins determined by experimental and computational methods have been superposed on the reference pathways from the KEGG database to identify mitochondrial pathways. Enzymes at the entry and exit points for each reconstructed pathway were identified, and mitochondrial solute carrier proteins were determined where applicable. Intermediate enzymes in the mitochondrial pathways were identified based on the annotations available from public databases, evidence in current literature, or our MITOPRED program, which predicts the mitochondrial localization of proteins. Through integration of the data derived from experimental, bibliographical, and computational sources, we reconstructed the amino acid metabolic pathways in human mitochondria, which could help better understand the mitochondrial metabolism and its role in human health.
