Data on breakthrough SARS-CoV-2 Delta variant infections in vaccinated individuals are limited.
We studied breakthrough infections among Oxford-AstraZeneca vaccinated healthcare workers in an ...infectious diseases hospital in Vietnam. We collected demographic and clinical data alongside serial PCR testing, measurement of SARS-CoV-2 antibodies, and viral whole-genome sequencing.
Between 11th–25th June 2021 (7-8 weeks after the second dose), 69 staff tested positive for SARS-CoV-2. 62 participated in the study. Most were asymptomatic or mildly symptomatic and all recovered. Twenty-two complete-genome sequences were obtained; all were Delta variant and were phylogenetically distinct from contemporary viruses obtained from the community or from hospital patients admitted prior to the outbreak. Viral loads inferred from Ct values were 251 times higher than in cases infected with the original strain in March/April 2020. Median time from diagnosis to negative PCR was 21 days (range 8–33). Neutralizing antibodies (expressed as percentage of inhibition) measured after the second vaccine dose, or at diagnosis, were lower in cases than in uninfected, fully vaccinated controls (median (IQR): 69.4 (50.7-89.1) vs. 91.3 (79.6-94.9), p=0.005 and 59.4 (32.5-73.1) vs. 91.1 (77.3-94.2), p=0.043). There was no correlation between vaccine-induced neutralizing antibody levels and peak viral loads or the development of symptoms.
Breakthrough Delta variant infections following Oxford-AstraZeneca vaccination may cause asymptomatic or mild disease, but are associated with high viral loads, prolonged PCR positivity and low levels of vaccine-induced neutralizing antibodies. Epidemiological and sequence data suggested ongoing transmission had occurred between fully vaccinated individuals.
Wellcome and NIH/NIAID
ICTACS 2006 Ho, Bao T; Dong, Thuy T. B; Duong, Due A ...
2007., 2006-12-29
eBook
This volume brings together many contributions from leading research scientists, engineers and practitioners in computer science. Selected by program committee members, the topics describe innovative ...research and new technologies in the following areas of interest: image processing, computer vision and pattern recognition; computational linguistics and natural language processing; artificial intelligence, machine learning and algorithms; software engineering; computer networks and security; and bioinformatics.
Cordyceps neovolkiana DL0004 is a group of insect parasitic fungi collected at an altitude of 1650 m above sea level at the top of Langbiang Mountain, Lam Dong province, Vietnam. C. neovolkiana ...DL0004 has been used in traditional medicine and possesses numerous biological effects such as anti-cancer, anti-inflammation, antioxidant properties. In this research, the fungi biomass and fruiting body of C. neovolkiana DL0004 were cultured and examined for their antioxidant properties using test methods such as reducing power, scavenging 2,2’-diphenyl-1-picrylhydrazyl (DPPH) free radical, neutralizing 2,2’-azinobis(3-ethylbenzothiazonline-6-sulfonate (ABTS) free radical, and inhibiting xanthine oxidase (XO). The results showed that all 7 extracts of the biomass were more active than the fruiting bodies of C. neovolkiana DL0004. Furthermore, the ethyl acetate (EtOAc) extract of C. neovolkiana DL0004 biomass showed DPPH, ABTS, and XO free radical scavenging with IC50 values (the concentration of the sample required to inhibit 50% of radical) of 107.01 μg/ml, 111.91 μg/ml, and 106.2248 μg/ml, respectively. Moreover, the reducing power of the EtOAc from C. neovolkiana DL0004 biomass was 0.184 at 1000 μg/ml.From the obtained results, the biomass EtOAc fraction extract of C. neovolkiana DL0004 was demonstrated to contain antioxidant compounds with potential applications in the production of functional foods.
Electrochemical polymerisation of 3-hexylthiophene (3HT) and electrochemical copolymerisation of 3HT and N-benzoyl dithienopyrrole (BDP) were performed to prepare polymer and copolymer films using a ...linear sweep voltammetry potentiostatic technique with a voltage range from 1.7-1.8 V and a scan rate of 0.1 mV/s. Cyclic voltammetry (CV) curves, Fourier-transform infrared (FTIR) spectra, scanning electron microscope (SEM) images, and UV-Vis absorption spectra of the polymer and copolymer were recorded for analysis and comparison of the electropolymerisation process and properties of the resultant films. The SEM photographs of the copolymer base on 3HT and BDP exhibited a rigid structure with large spherical aggregates with an average size around 200 nm. The copolymer of 3HT and BDP exhibited the band gaps of 2.25 eV which was determined via electrochemical measurement that is higher than of band gaps of homopolymer poly(3-hexylthiophene) (P3HT). The copolymer’s energy bandgap HOMO-LUMO was enhanced compared to polymer P3HT. Moreover, the increased conjugation length significantly improved the morphology structure as well as the electrochemical stability of the conjugated copolymer.
Elevated levels of pollutants, including heavy metals, resulting from human activities, have raised concerns regarding their adverse impacts on natural ecosystems. Among these, aquatic organisms, ...particularly non-target microalgae, bear substantial consequences from such contaminants. This study endeavored to evaluate the impact of the heavy metal lead (Pb) at concentrations of 2.5, 25, and 250 μg L−1 on the growth and lipid content of the diatom Cyclotella meneghiniana in a 14-day toxicity test conducted under controlled laboratory conditions. The findings indicate that lower Pb concentrations (2.5 and 25 μg L−1 ) fostered algal proliferation, whereas exposure to 250 μg L−1 resulted in complete inhibition in two distinct endpoints. Additionally, no significant fluctuations in algal lipid content were discernible between exposure to 2.5 and 25 μg Pb L−1 and the control group. This study stands as a pioneering effort in unveiling the toxicity of Pb on C. meneghiniana, shedding light on the species’ susceptibility to this heavy metal and underscoring the necessity of incorporating this species into ongoing ecological risk assessments of Pb.
Air pollution is the leading environmental agent that poses a severe threat to human health and is one of the most severe problems in cities. Of the pollutants, particulate matter (PM), especially ...particles less than 2.5 microns in diameter, has the most profound health impacts. Urbanization and industrialization in cities have made the air quality up there worse and worse. Our study was based on the Aerosol Optical Depth (AOD) feature, a parameter obtained by remote sensing that relates to the presence of airborne particles potentially associated with PM. In this study, the PM2.5 concentration data from the ground monitoring station and the MODIS AOD product of 3 km resolution were correlated to build a suitable regression function to simulate the spatial distribution of PM2.5 concentrations. Next, the AOD was retrieved from the Landsat image based on the characteristics of the decrease in atmospheric clarity caused by the pollution particles. Landsat AOD has a 600m higher resolution than MODIS AOD. Research results on air quality (AQ) were simulated on Landsat AOD image through PM2.5 concentration distribution and air quality index (AQI), in which AQI was determined based on USEPA standards. The analysis shows that the linear regression function between PM2.5 concentration and MODIS AOD correlated best with the correlation coefficient R=0.9. Then PM2.5 distribution was established on Landsat AOD image with higher spatial resolution. Case analysis for March of 2018 reflected that the average concentration of PM2.5 across Ho Chi Minh City (HCMC) was higher than the allowable threshold specified in QCVN05:2013/BTNMT. PM2.5 concentration in central districts tended to be higher than in suburban districts. The study also found that the city average AQI-PM2.5 was around 97.38, peaking at 159, which was in the Unhealthy range, especially for sensitive groups. The result of the study provides potential solutions for AQ monitoring at the city level with a detailed spatial distribution.
In this study, chitin was chemically extracted from shrimp shell, and then used for the development of a chitin hydrogel-based moisture supporter for hydroponic systems. Here, the chitin hydrogel was ...prepared at different concentrations of lithium chloride (LiCl), varying from 5 to 9%, in N,N-dimethylacetamide (DMAc) at room temperature. The results revealed that, while most characteristic functional groups of the chitin segment remained intact in all chitin hydrogels, higher levels of LiCl in DMAc led to a reduction in both crystalline index and equilibrium water content in the resulting chitin hydrogel. In a seed germination experiment, it was observed that the chitin hydrogel containing 5% LiCl concentration exhibited superior results in terms of root, stem, and leaf length, compared to other concentrations. Therefore, the chitin hydrogel was an effective moisture-supporter for seed germination and early plant development, compared conventional soil used as control. Moreover, SEM images illustrated that the chitin hydrogel possessed a pliable structure, indicating improved degradation when subjected to composting over a 15-day period.
A conjugated molecular triad based on pyrene and 9,9-dioctyl-9H-fluorene has been successfully synthesised via the Suzuki cross-coupling reaction with yield of 48%. In this polymerization, the ...Pd(PPh3)4 has been used as the catalytic in the presence of K2CO3 as base in a mixture of toluene/ethanol/H2O at 80oC under N2. The chemical structures of the conjugated molecules were determined via Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR) that proved the chemical structure of 1,1’-(9,9-dioctyl-9H-fluorene-2,7-diyl)dipyrene. The optical properties of the molecules were investigated via UV-Vis in different concentration that exhibited the maximum absorption of 340 nm. The conjugated molecular triad also have been investigated by fluorescence spectroscopy that showed a mission peak at 475 nm under the excitation of 350 nm of wavelength. In addition, the 1,1’-(9,9-dioctyl-9H-fluorene-2,7-diyl)dipyrene exhibited a fluorescence quenching as a chemosensor in the presence of mesotrione, a nitroaromatic herbicide. This phenomenon proved the efficient energy and electron transfer from a photo-excited pyrene moiety to the ground state electron-deficient mesotrione as a result of Forster resonance energy transfer (FRET) mechanism.
Conventional optimal power flow studies neglect the effect of temperature on resistance for simple calculation. However, the branch resistance changes with the change of temperature. Thus, the ...optimal power flow (OPF) should consider the temperature effect for accurate calculation. Moreover, contingency cases should be considered to ensure system security. Accordingly, the security-constrained temperature-dependent optimal power flow (SC-TDOPF) emerges as a critical and practical issue in power systems. To deal with the SC-TDOPF problem, this study suggests a hybrid method, namely pseudo-gradient based particle swarm optimization and differential evolution method (PGPSO-DE). The suggested PGPSO-DE method is applied to the standard IEEE 30 bus system under normal condition as well as contingency condition. The findings have shown that the PGPSO-DE method provides better solution quality than other studied optimization methods. Consequently, the PGPSO-DE method proves its effectiveness in solving the complex SC-TDOPF problem.
PDF
