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Meadows McIntyre opublikował 1 rok, 3 miesiące temu
The stabilization efficacy of the ZIF-8 coating is comparable to the current „gold standard” refrigeration approach, and superior to the commonly used sucrose coating method. This approach will greatly improve the shelf-life and stability of antibody-coated ELISAs and other types of assays which utilize surface-bound antibodies, thus extending biomedical research and medical diagnostics to resource-limited settings.The clinical and public health utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic testing requires a better understanding of the dynamics of the humoral response to infection. To track seroconversion of IgG and IgM antibodies in patients with SARS-CoV-2 infection and its association with patient and clinical factors and outcomes. Residual patient specimens were analyzed on the Abbott ARCHITECT i2000 instrument using the Abbott SARS-CoV-2 IgG assay and prototype SARS-CoV-2 IgM assay. Age, sex, comorbidities, symptom onset date, mortality, and specimen collection date were obtained from electronic medical records. Three hundred fifty-nine longitudinal samples were collected from 89 hospitalized patients 0 to 82 days postsymptom onset. Of all, 51.7% of the patients developed IgG and IgM antibodies simultaneously; 32.8% seroconverted for IgM before IgG. On average, patients seroconverted for IgG by 8 days and for IgM by 7 days postsymptom onset. All patients achieved IgG seropositivity by 19 days and IgM seropositivity by 17 days. Median time to IgG and IgM seroconversion was prolonged and initial levels of IgG were lower in immunocompromised patients and patients less then 65 years of age compared to immune competent patients and those ≥65 years of age. Immunocompromised patients also had persistently lower levels of IgM that peaked on day 17.6 and decreased thereafter compared to immune competent patients. IgM seroconversion in patients who died reached significantly higher levels later after symptom onset than in those who recovered. SARS-CoV-2 infected patients have similar time to seroconversion for IgG and IgM. However, differences in immune status and age alter time to seroconversion. These results may help guide serologic testing application in COVID-19 management.
The persistence of circulating antibodies to SARS-CoV-2 infection is not yet well known. We compare the results of 2 automated systems for the determination of IgG against SARS CoV-2 and assess the time-course of the IgG response.
IgG were measured in 103 specimens of 55 patients with COVID-19 (time from the symptoms’ onset 3-187 days) using the automated tests „Abbott SARS-COV-2 IgG” and „MAGLUMI 2019-nCoV IgG”.
The 2 methods had a concordance of 90.3%, but the quantitative correlation, although significant, showed dispersed results. All the specimens resulted positive after 17 days. However, the median concentrations of IgG rapidly increased up to 20 days and decreased for Maglumi IgG while Abbott IgG showed a constant trend up to 85 days, and then slowly declined.
The titer of IgG against SARS-CoV-2 may significantly and rapidly decrease, but with a very different time-course depending on the method used for the determination.
The titer of IgG against SARS-CoV-2 may significantly and rapidly decrease, but with a very different time-course depending on the method used for the determination.There is growing concern due to the emergence of multidrug resistance in Neisseria gonorrhoeae. A rapid molecular test which guides and provides antimicrobial susceptibility knowledge prior to start of treatment is needed. This study evaluated the clinical performance of the ResistancePlus GC assay compared to in-house PCR and antimicrobial susceptibility results for ciprofloxacin resistance. Samples were selected from a range of sites with corresponding cultures isolated from the same patient episode. The ResistancePlus GC assay displayed high sensitivity for N. gonorrhoeae detection (98.5%) and gyrA detection (97.1%). There was high agreement (98.9%) between the ResistancePlus GC assay and culture phenotype. Mixed population testing showed that the assay was able to detect resistance in a sample containing a minority variant of 27% resistant. The ResistancePlus GC assay performed well and could be used to provide a clinically relevant indication of ciprofloxacin susceptibility for the treatment of gonorrhoea.Tocilizumab, an interleukin-6 receptor antagonist, has been used to treat critically ill patients with coronavirus disease-2019. We present the case of a previously immunocompetent man with coronavirus disease-2019 who developed invasive pulmonary aspergillosis after treatment with tocilizumab, illustrating the importance of considering opportunistic infections when providing immune modulating therapy.Recently, the growing environmental concerns and economic demands have driven the need to develop effective solutions for the treatment of vegetal fibers to be used as renewable source for various industrial applications. The present study aimed to explore pineapple crown fibers (PCs) as an alternative source of cellulose. The three treatments (alcohol-insoluble residue (AIR), alkaline (AT), and organosolv) evaluated promoted chemical and morphological changes to the PCs. Fresh and treated PCs were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), thermogravimetric analysis (TG), and chemical composition. The XRD results showed that the Cellulose-I allomorph was not altered during extraction, and that the crystallinity index of the fibers treated with AT, first bleaching step, second bleaching step, and the second bleaching step followed by KOH treatment (2B_KOH) increased to 77.8; 83.2; 83.5 and 86% when compared with fresh PC (62.3%). Results from the thermal analysis revealed that thermal stability increased for the isolated cellulose, and the maximum degradation for (2B_KOH) is 350 °C. Chemical composition results showed a decrease in the content of hemicellulose, lignin and other soluble materials after alkaline treatment, suggesting high-quality 2B_KOH with 74.6% of cellulose. SEM revealed changes in the morphological structure on fibers. Alkaline treatment followed by H2O2 bleaching is an excellent alternative for the removal of non-cellulosic material and facilitates the isolation of cellulose. These results suggested that there is a potential to isolate cellulose from PC via the sequence of treatment of a methodology by chlorite-free.Environmental pollution caused by human activities in the Yangtze River Basin (YRB), especially nitrogen pollution, has always been a hot topic. High-intensity anthropogenic nitrogen (AN) inputs have undergone some changes on account of environmental management practices in the YRB. We used the latest statistical data (2000-2017) to estimate spatiotemporal heterogeneity of AN inputs across the YRB, characterize hotspots of AN inputs, and predict the future trend, which is critical to meet nitrogen management challenges. We found agricultural sources were major contributors to nitrogen inputs (more than 70%) in the YRB. Due to the reduction in agricultural fertilizers use in China, AN inputs had gradually decreased from a peak of 19.0 Tg/yr in 2014 after a rapid growth period. Additionally, the nitrogen flux in sub-catchments and from various sources indicated an increasing distribution characteristic from the upper reaches to the lower reaches. Hotspots of AN inputs were mainly concentrated in the Sichuan Basin and the Middle-Lower Yangtze Plain (more than 50 tons/km2), however, growth rates were relatively low or even negative. STIRPAT model showed population size was the most important factor affecting AN loads. Although the growth rate would slow down in the future, AN loads would be maintained at a high level. Besides, aquaculture had become an important source of potential nitrogen growth in the whole basin, although the contribution was relatively small at present. Controlling nitrogen loads in hotspots and avoiding high inputs of new nitrogen sources should be the focus of future nitrogen environmental management.Mineral processing, pyro- and hydrometallurgical processes of auriferous sulfide ores and porphyry copper deposits (PCDs) generate arsenopyrite-rich wastes. These wastes are disposed of into the tailings storage facilities (TSF) in which toxic arsenic (As) is leached out and acid mine drainage (AMD) is generated due to the oxidation of arsenopyrite (FeAsS). To suppress arsenopyrite oxidation, this study investigated the passivation of arsenopyrite by forming ferric phosphate (FePO4) coating on its surface using ferric-catecholate complexes and phosphate simultaneously. Ferric iron (Fe3+) and catechol form three types of complexes (mono-, bis-, and triscatecholate complexes) depending on the pH, but mono-catecholate complex (i.e.,[Fe(cat)]+) became unstable in the presence of phosphate because the chemical affinity of Fe3+-PO43- is most probably stronger than that of Fe3+-catechol in [Fe(cat)]+. When two or more catechol molecules were coordinated with Fe3+ (i.e., [Fe(cat)2]- and [Fe(cat)3]3-), however, these complexes were stable irrespective of the presence of phosphate. The treatment of arsenopyrite with [Fe(cat)2]- and phosphate could suppress its oxidation due to the formation of FePO4 coating, evidenced by SEM-EDX and XPS analyses. The mechanism of FePO4 coating formation by [Fe(cat)2]- and phosphate was confirmed by linear sweep voltammetry (LSV) (1) [Fe(cat)2]- was oxidatively decomposed and (2) the resultant product (i.e., [Fe(cat)]+) reacts with phosphate, resulting in the formation of FePO4.In this study, magnetic Cu and Ni bimetallic particles embedded carbon sheets, namely as C@Cu-Ni, was derived via calcining a mixture of Cu-MOFs and Ni-MOFs (mass ratio = 46) under N2 protection and served as a catalyst for the degradation of 2,4,6-trichlorophenol (2,4,6-TCP) by peroxymonosulfate (PMS). The results showed that more than 98.5% of 2,4,6-TCP (10 mg L-1) was rapidly decomposed at initial pH = 5, PMS = 1 mM and catalyst dosage = 0.1 g L-1 within 30 min, accompanied by 42.47% removal of total organic carbon (TOC). This fully confirmed that C@Cu-Ni possessed excellent catalytic performance for PMS activation. The radical quenching experiments and electron paramagnetic resonance (EPR) investigation testified that the reactive oxygen species (ROS) included SO4•-, •OH, O2•- radicals and singlet oxygen (1O2), which were responsible for the rapid degradation of 2,4,6-TCP. Among them, O2•-and 1O2 played a decisive role. Cyclic voltammograms (CV) and electrochemical impedance spectroscopy (EIS) revealed that C@Cu-Ni material possessed superior electrical conductivity and electron transfer, improving its catalytic activity. What is more, C@Cu-Ni displayed excellent stability and could be consecutively used for five times without any decline of catalytic performance. The main intermediates of the 2,4,6-TCP degradation were analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) and possible pathways of 2,4,6-TCP degradation were further proposed. The extraordinary stability and superior catalytic activity of C@Cu-Ni coupled with its easy separation from wastewater due to magnetism suggest that the newly synthesized material may offer a promising alternative approach to efficiently degrade organic pollutants by PMS.


