Seroprevalence and risk factors of Toxoplasma gondii infections among high-risk populations in Changzhou City / 中国血吸虫病防治杂志

Objective To understand the prevalence and risk factors of Toxoplasma gondii infections among high-risk populations in Changzhou City, so as to provide the scientific basis for formulating effective control measures of toxoplasmosis. MethodsFour types of high-risk populations living in Changzhou City were recruited from 2016 to 2018 as the study subjects, including HIV/AIDS patients, cancer patients, pregnant women and livestock and poultry breeding or processing workers. Each subject was investigated for the knowledge on knowledge, attitude and practice of toxoplasmosis prevention and control. In addition, serum specific IgG and IgM antibodies against T. gondii were detected, and the risk factors of T. gondii infections were identified. Results A total of 900 participants at high risk of T. gondii infections were investigated in Changzhou City from 2016 to 2018, including 150 HIV/AIDS patients, 250 cancer patients, 250 pregnant women and 250 livestock and poultry breeding or processing workers. The overall awareness rate of toxoplasmosis prevention and control knowledge was 16.8% (151/900), and the awareness rate was significantly greater in women than in men (χ2 = 41.34, P < 0.05). The awareness rate of toxoplasmosis prevention and control reduced with ages (χ2 = 147.78, P < 0.05), and increased with the education level (χ2 = 166.42, P < 0.05). In ad dition, there was an occupation-specific awareness rate of toxoplasmosis prevention and control (χ2 = 92.26, P < 0.05), and the highest awareness rate was seen in cadres and staff (47.2%, 34/72). Among all high-risk populations, 34.6% (311/900) had fre- quent contacts with cats/dogs, 40.4% (364/900) raised cats/dogs at home, 0.9% (8/900) ate raw meat, and 15.8% (142/900) sepa- rated chopping boards for raw and cooked food. Among the participants aware of toxoplasmosis prevention and control knowledge, 24.5% (37/151) contacted cats/dogs frequently, which was significantly lower than those not aware of toxoplasmosis prevention and control knowledge (36.6%, 274/749) (χ2 = 8.11, P < 0.05), and 35.1% (53/151) separated chopping boards for raw and cooked food, which was significantly higher than those not aware of toxoplasmosis prevention and control knowledge (11.9%, 89/749) (χ2 = 50.97, P < 0.05). The overall seroprevalence of T. gondii infections was 11.0% (99/900), and the positive rates of IgG antibodies against T. gondii were 6.0%, 13.9%, 4.8% and 17.3% in HIV/AIDS patients, livestock and poultry breeding or processing workers, pregnant women and cancer patients, respectively (χ2 = 25.87, P < 0.05). A higher seroprevalence of T. gon- dii infection was seen in men than in women (χ2 = 8.88, P < 0.05), and the seroprevalence increased with ages (χ2 = 37.03, P < 0.05) and reduced with education levels (χ2 = 25.07, P < 0.05). There was an occupation-specific seroprevalence of T. gondii in- fection (χ2 = 22.09, P < 0.05), and the highest seroprevalence was detected in peasants (57/330, 17.3%). Conclusions The awareness of toxoplasmosis prevention and control knowledge is low among high-risk populations in Changzhou City. Health edu- cation pertaining to toxoplasmosis prevention and control requires to be strengthened in cancer patients and livestock and poultry breeding or processing workers who have a high seroprevalence of T. gondii infections, so as to change the poor behavior styles.

Theoretical insight into the mechanism of photoreduction of CO2 to CO by graphitic carbon nitride.

Graphitic carbon nitride (g-C3N4) is a promising photocatalyst for the reduction of CO2 into fuels. However, the reduction mechanism of CO2 using g-C3N4 is not clear in the literature. In the present study, the fixation of CO2 and the formation of carbamate on the nitrogen atom at the edge of g-C3N4 were investigated using first-principles density functional theory. The calculated results shows that two adjacent bare nitrogen atoms at the edge of g-C3N4 could be the activation sites for the proton and CO2 molecule respectively, which are crucial to the formation of carbamate. The calculated energy barrier of carbamate formation is 0.95 eV for a preferential pathway. From studies on these micro processes, we propose a mechanism with proton assistance for the g-C3N4-catalyzed photoreduction of CO2 to CO.

Exploring the formation and electronic structure properties of the g-C3N4 nanoribbon with density functional theory.

The optical properties and condensation degree (structure) of polymeric g-C3N4 depend strongly on the process temperature. For polymeric g-C3N4, its structure and condensation degree depend on the structure of molecular strand(s). Here, the formation and electronic structure properties of the g-C3N4 nanoribbon are investigated by studying the polymerization and crystallinity of molecular strand(s) employing first-principle density functional theory. The calculations show that the width of the molecular strand has a significant effect on the electronic structure of polymerized and crystallized g-C3N4 nanoribbons, a conclusion which would be indirect evidence that the electronic structure depends on the structure of g-C3N4. The edge shape also has a distinct effect on the electronic structure of the crystallized g-C3N4 nanoribbon. Furthermore, the conductive band minimum and valence band maximum of the polymeric g-C3N4 nanoribbon show a strong localization, which is in good agreement with the quasi-monomer characters. In addition, molecular strands prefer to grow along the planar direction on graphene. These results provide new insight on the properties of the g-C3N4 nanoribbon and the relationship between the structure and properties of g-C3N4.

Al atom on MoO3(010) surface: adsorption and penetration using density functional theory.

Interfacial issues, such as the interfacial structure and the interdiffusion of atoms at the interface, are fundamental to the understanding of the ignition and reaction mechanisms of nanothermites. This study employs first-principle density functional theory to model Al/MoO3 by placing an Al adatom onto a unit cell of a MoO3(010) slab, and to probe the initiation of interfacial interactions of Al/MoO3 nanothermite by tracking the adsorption and subsurface-penetration of the Al adatom. The calculations show that the Al adatom can spontaneously go through the topmost atomic plane (TAP) of MoO3(010) and reach the 4-fold hollow adsorption-site located below the TAP, with this subsurface adsorption configuration being the most preferred one among all plausible adsorption configurations. Two other plausible configurations place the Al adatom at two bridge sites located above the TAP of MoO3(010) but the Al adatom can easily penetrate below this TAP to a relatively more stable adsorption configuration, with a small energy barrier of merely 0.2 eV. The evidence of subsurface penetration of Al implies that Al/MoO3 likely has an interface with intermixing of Al, Mo and O atoms. These results provide new insights on the interfacial interactions of Al/MoO3 and the ignition/combustion mechanisms of Al/MoO3 nanothermites.

The effect of water on the structural, electronic and photocatalytic properties of graphitic carbon nitride.

g-C3N4, as a typical metal-free catalyst for water splitting, has attracted special attention. The structural and electronic properties of water adsorption on g-C3N4 play a key role in understanding the water splitting mechanism at the atomic level. The properties of a single g-C3N4 sheet and the water adsorption on a single g-C3N4 sheet were thoroughly explored based on density functional theory (DFT) calculations. The results show that water adsorption on one side of the single g-C3N4 sheet will lead the initial flat structure to change to a buckle one, while water molecule adsorption on both sides of g-C3N4 will not disturb the flat structure. The flat g-C3N4 is an indirect semiconductor, and interestingly the band structure of g-C3N4 changes from an indirect to a direct one during the flat structure transformation from flat to buckle because of the water adsorption. Water molecules prefer to adsorb around the intrinsic vacancy of the single g-C3N4 sheet at low coverage, and further adsorbed water molecules stay around the intrinsic vacancy. Water adsorption also affects the band edge position of g-C3N4 for water splitting. These results provide a deep insight into the structure and adsorption properties of g-C3N4 in the water environment, which will greatly help to design a new type of metal-free catalyst for water-splitting.

[Analysis of the distribution of VOCs concentration field with oil static breathing loss in internal floating roof tank].

Internal floating roof tank has the advantages of external floating roof tank and fixed roof tank and has its own evaporation loss properties. The influences of volatile organic compounds (VOCs) distribution gradient, molecular diffusion, thermal diffusion and forced convection on the evaporation loss of oil were studied in the space of the homemade platform of an internal floating roof tank. The results showed that thermal diffusion with temperature change was the main cause for the static loss in the internal floating roof tank. On this basis, there were some measures for reduction of the evaporation loss and formulas to calculate the evaporation loss of the internal floating roof tank in this research.

Molecular dynamics study of the response of nanostructured Al/Ni clad particles system under thermal loading.

Molecular dynamics simulations are used to study the exothermic alloying reactions by imposing a thermal loading on a local area of nanostructured Al/Ni clad particles. The combustion parameters, such as particles size, density, and ignition temperature, are characterized. Reducing the size of Al/Ni clad particles makes the propagation velocity of reaction front increase but lowers both the adiabatic combustion temperature and pressure of the system. However, increasing either mass density or ignition temperature makes the propagation velocity of reaction front increase and raises the adiabatic temperature and pressure as well. We estimate the propagation velocity of the chemical reaction front to range from 35.70 to 44.06 m/s.