Effect of Nitrogen Cation as "Electron Trap" at π-Linker on Properties for p-Type Photosensitizers: DFT Study.

On the basis of thieno(3,2-b)thiophene and dithieno[3,2-b:2',3'-d]thiophene (T2 and T3 moieties) as π-linker, the A, D and S series dyes were designed to investigate the effect of the introducing N+ as an "electron trap" into T2 and T3 on the properties of the dyes. The optimized structures, electronic and optical properties were investigated by the density functional theory (DFT) and time-dependent DFT (TD-DFT). The results show that the properties of the dyes are sensitive to the N+ position in π-linkers. D series dyes with electron-withdrawing units located near the donor have better properties than the corresponding A series with the electron-withdrawing units located near the acceptor. For A and D series, the N+ modified dye named T2N+1-d displays the largest red shift of the UV-vis absorption, the maximum integral values of the adsorption-wavelength curves over the visible light, the highest light harvesting efficiency (LHE, 0.996), and the strongest adsorption energy (-44.33 kcal/mol). T2N+1-d also has a large driving force of hole injection (ΔGinj, -0.74 eV), which results in a more efficient hole injection. Bearing a lengthier π-linker than T2N+1-d, the properties of T2N+1-s are further improved. T2N+1-d moiety or its increased conjugated derivatives may be a promising π-linker.

[Hydatidosis Prevalence in 6- to 12-year-old Children in Southern Xinjiang].

Objective: To understand the hydatidosis prevalence in 6- to 12-year-old children in southern Xinjiang Uygur Autonomous Region and provide scientific basis for formulation of control measures. Methods: One primary school was selected from each of the pastoral area, pastoral-agricultural area, agricultural area, and township area in 42 counties （cities） of southern Xinjiang, using the stratified sampling method. With the consent of their parents, B ultrasonic abdominal scan and venous blood collection were performed on all the children （6-12 years） in the selected schools. Serum level of echinococcus antibody IgG was determined by ELISA. Hydatidosis prevalence and the serum level of IgG in these children were analyzed. Results: A total of 80 429 children were examined from 168 primary schools. B ultrasonic scan revealed hydatidosis in 9 children （0.01%）, comprising 3 cases in Kezhou, 2 in Aksu, 2 in Bazhou, and 2 in Kashi. ELISA results showed that 4 189 children were positive for serum IgG, with a positive rate of 5.21%. The positive rate was highest in Kashi （8.41%, 2 143/25 495）, followed by Aksu （5.69%, 913/16 051）, with significant difference between different areas （χ2=977.303， P<0.01）. The positive rate was lowest in 6-year children （2.13%, 44/2 065） and highest in 11-year children （5.68%, 822/14 462） （χ2=48.221, P<0.01）. In addition, the positive rate was highest in Uighur children（5.19%, 3 899/75 115）, followed by Mongolian children （4.27%, 68/1 592）, with no significant difference between ethnic groups （χ2=4.072, P>0.05）. Among the children of residents, children with a nomadic lifestyle, and children settled in winter and living in a nomadic lifestyle in summer, hydatidosis occurred in 7 residents and 2 children who settled in winter and living in a nomadic lifestyle in summer; and the positive rate of serum antibody was 5.45% （184/77 512）, 2.97% （3/101）, 0.07% （2/2 816）, respectively（χ2=148.609, P<0.01）. Conclusion: There is a low hydatidosis prevalence in 6- to 12-year-old children in southern Xinjiang, but the positive rate of serum echinococcus IgG in kashgar region, Uighur ethnicity, and children of the resident group are relatively high.

Prevalence of Cystic Echinococcosis in Slaughtered Sheep as an Indicator to Assess Control Progress in Emin County, Xinjiang, China.

Hydatid disease imposing serious threat on human health and great loss in live¬stock pastoralism remains a major public health problem in western China. To assess and monitor the effect of control program on transmission dynamics, we used the prevalence of cystic echinococcosis in slaughtered sheep at slaughterhouse as an indicator during the period of 2007 to 2013 in Emin County, Xinjiang Uygur Autonomous Region, China. The results showed a significant decline trend of prevalence in all age groups during the 7 years when the control program was implemented; particularly, the rate was reduced by 72% after first 3 years. Among the sheep slaughtered, the age distribution evidenced that the prevalence increased significantly as the sheep grew older. The baseline data indicated that the rate was 4.5% at the age <1, 6.7% at age 2~, and reached to the highest 17.9% at age ≥ 4 years. Earlier response to the intervention pressure was seen in the sheep at the younger age. Significant decline started from 2008 at the age <1, from 2009 at age of 1~, 2010 at 2~ to 3~, and the latest, in 2012 at age ≥ 4. This study demonstrated that the prevalence of cystic echinococcosis in slaughtered sheep may be used as an indicator to assess and monitor the transmission status during and after control program providing information for betterment of performance to sustain control strength.

[Retrospective analysis of echinococcosis surgerical cases in Xinjiang from 2005 to 2013].

UNLABELLED: [Abstract] OBJECTIVE: To analyze the situation of echinococcosis surgerical cases in Xinjiang Uygur Autonomous Region from 2005 to 2013. METHODS: The surgery cases of echinococcosis in Xinjiang from 2005 to 2013 were collected, and analyzed with SPSS 17.0 and Epi Info 3.5.3 software. RESULTS: A total of 8 639 hydatid disease cases were reported during 2005-2013 from 94 counties (cities and districts) of 14 prefectures (municipalities) in the Region. The average number of annual operation cases were 960 cases (8,639/9 years), and the annual incidence was 4.40/100,000 (960/21.81 million). 82.8% (7,152/8,639) of report cases came from northern Xinjiang area with an incidence of 7.59/100,000, and 17.2% (1,487/8,639) distributed in southern Xinjiang area with an incidence of 1.58/100,000. There were 373 cases (4.4%, 373/8,639) reported in 2005, and increased to 1434 cases (16.5% 1,434/8,639) in 2013 (P<0.05). The cases mainly distributed in Yili Kazak Autonomous Prefecture (2,028 cases), Tarbagatai Prefecture (1,218 cases), Changji Hui Autonomous Prefecture (1,179 cases), and Urumqi City (1,128 cases) of the northern Xinjiang area. There were 4,557 male (52.8%, 4,557/8,639) and 4 082 famale patients (47.3%, 4,082/8,639)(P<0.05). The age distribution showed a single-peak curve, and more patients concentrated in the age group of 31-40 years, accounting for 26.2% (2,265/8,639). Among 8,639 cases, farmers accounted for 47.9% (4 134/8 639). CONCLUSION: The nunber of surgical cases of echinococcosis increases every year in Xinjiang since 2005, and the distribution of the disease shows a trend from the agricultural and pastoral areas to the towns.

Prevalence and spatial distribution characteristics of human echinococcosis: A county-level modeling study in southern Xinjiang, China.

Objectives: Human echinococcosis remains an important public health problem. The aim of this study was to analyze the prevalence and spatial distribution characteristics of human echinococcosis cases in southern Xinjiang, China from 2005 to 2021. Methods: Human echinococcosis cases were collected from the National Infectious Disease Reporting System. Joinpoint regression analysis was performed to explore the trends. Spatial autocorrelation, hot spot analysis, as well as spatial-temporal clustering analysis were conducted to confirm the distribution and risk factors. Results: A total of 4580 cases were reported in southern Xinjiang during 2005-2021, with a mean annual incidence of 2.56/100,000. Echinococcosis incidence showed an increasing trend from 2005 to 2017 (APC = 17.939, 95%CI: 13.985 to 22.029) and a decreasing trend from 2017 to 2021 (APC = -18.769, 95%CI: 28.157 to -8.154). Echinococcosis cases had a positive spatial autocorrelation in 2005-2021 (Moran's I = 0.19, P < 0.05). The disease hotspots were located in the east and west in these areas, then returned to the east clusters, including Hejing, Heshuo, Wuqia, Atushi, Aheqi, and Yanqi Hui Autonomous County. Meanwhile, spatial-temporal analysis identified the first cluster comprised of five counties (cities): Yanqi Hui Autonomous County, Korla City, Bohu County, Hejing County, and Heshuo County. And secondary clusters 1-3 are predominantly in Wushi County, Aheqi County, Keping County, Atushi City, Wuqia County and Cele County. Conclusions: Our findings suggest that echinococcosis is still an important zoonotic parasitic disease in southern Xinjiang, yet it showed a certain degree of spatial clustering. It is crucial to implement comprehensive prevention and control measures to effectively combat the epidemic of echinococcosis.

Epidemiological characteristics and risk factors for cystic and alveolar echinococcosis in China: an analysis of a national population-based field survey.

BACKGROUND: Human cystic and alveolar echinococcosis are neglected tropical diseases that WHO has prioritized for control in recent years. Both diseases impose substantial burdens on public health and the socio-economy in China. In this study, which is based on the national echinococcosis survey from 2012 to 2016, we aim to describe the spatial prevalence and demographic characteristics of cystic and alveolar echinococcosis infections in humans and assess the impact of environmental, biological and social factors on both types of the disease. METHODS: We computed the sex-, age group-, occupation- and education level-specific prevalences of cystic and alveolar echinococcosis at national and sub-national levels. We mapped the geographical distribution of echinococcosis prevalence at the province, city and county levels. Finally, by analyzing the county-level echinococcosis cases combined with a range of associated environmental, biological and social factors, we identified and quantified the potential risk factors for echinococcosis using a generalized linear model. RESULTS: A total of 1,150,723 residents were selected and included in the national echinococcosis survey between 2012 and 2016, of whom 4161 and 1055 tested positive for cystic and alveolar echinococcosis, respectively. Female gender, older age, occupation at herdsman, occupation as religious worker and illiteracy were identified as risk factors for both types of echinococcosis. The prevalence of echinococcosis was found to vary geographically, with areas of high endemicity observed in the Tibetan Plateau region. Cystic echinococcosis prevalence was positively correlated with cattle density, cattle prevalence, dog density, dog prevalence, number of livestock slaughtered, elevation and grass area, and negatively associated with temperature and gross domestic product (GDP). Alveolar echinococcosis prevalence was positively correlated with precipitation, level of awareness, elevation, rodent density and rodent prevalence, and negatively correlated with forest area, temperature and GDP. Our results also implied that drinking water sources are significantly associated with both diseases. CONCLUSIONS: The results of this study provide a comprehensive understanding of geographical patterns, demographic characteristics and risk factors of cystic and alveolar echinococcosis in China. This important information will contribute towards developing targeted prevention measures and controlling diseases from the public health perspective.

Design of high performance p-type sensitizers with pyridinium derivatives as the acceptor by theoretical calculations.

Based on triphenylamine as an electron donor and thiophene as a π-linker, Series P and A p-type sensitizers were designed to investigate the effects of the different acceptors on the properties of the sensitizers. The optimized molecular structures, electronic and optical properties were investigated by density functional theory (DFT) and time-dependent DFT (TD-DFT). The results showed that the properties of the dyes can be tuned by the introduction of the different electron-withdrawing groups to the N atom in the pyridinium acceptor. Compared with the synthesized Series P dyes used in p-type sensitizers, the properties of Series A dyes, except for two dyes that cannot be used as p-type sensitizers, are improved by means of modifying pyridinium acceptors. Due to the suitable electron-withdrawing ability of the hexafluorodiacetylamino group in its acceptor, A6 has the narrowest energy gap (1.90 eV), the largest driving force of hole injection (ΔG inj, -0.68 eV), the high light harvesting efficiency (LHE, 0.9984) and the smallest internal reorganization energy (λ int, 5.05 kcal mol-1). Hence, A6 not only enhances electronic excitation, but also improves the reorganization energy. Importantly, A6 shows the largest red shift and the maximum integral values of the adsorption over the visible light, as well as the strongest adsorption energy (-74.80 kcal mol-1) on a NiO surface. Thus, A6 may be a promising sensitizer for the p-type dye-sensitized solar cells (DSSCs), and the acceptor of A6 may provide a new and easily accessible high performance acceptor for p-type sensitizers.

Theoretical study of nitrogen cation modified aromatics containing thiophene as π-linker for p-type photosensitizers.

On the basis of triphenylamine as an electron donor with attachment of two -COOH anchoring groups and dicyanovinyl as acceptor, ten dyes with D-π-A structures were designed to investigate the effects of different π-linker groups on the properties of the sensitizers, especially the influence of the π-linkers containing nitrogen cation (N+). The optimized structures and electronic and optical properties were investigated by the density functional theory (DFT) and time-dependent DFT (TD-DFT). The results show that all the investigated dyes can be used as dye sensitizers for the p-type dye-sensitized solar cells (DSSCs) except one dye which contains two N+. The N+ modified dye (named S3-PZL1C) has narrow energy gap (2.02 eV), the best light-harvesting efficiency (LHE, 0.9974), and the smallest internal reorganization energy (λint = 7.00 kcal/mol). Importantly, S3-PZL1C displays the largest red shift of the UV-vis absorption, the maximum integral values of the adsorption-wavelength curves over the visible light (400~800 nm), and the strongest adsorption energy (- 66.84 kcal/mol) on NiO surface. In addition, S3-PZL1C not only enhances the electronic excitation but also improves the reorganization energy and charge separation. The intramolecular charge transfer towards the acceptor is sensitive to the N+ position in π-linkers. Therefore, the suitable introduction of N+ in dyes can improve the performance of the dyes, and the PZL1C moiety may be a promising π-linker for p-type DSSCs. Graphical abstract.

Molecular docking and molecular dynamics simulation analyses of urea with ammoniated and ammoxidized lignin.

Ammoniated lignin, prepared through the Mannich reaction of lignin, has more advantages as a slow-release carrier of urea molecules than ammoxidized lignin and lignin. The advantages of the ammoniated lignin include its amine groups added and its high molecular mass kept as similar as that of lignin. Three organic molecules including guaiacyl, 2-hydroxybenzylamine and 5-carbamoylpentanoic acid are monomers respectively in lignin, ammoniated lignin and ammoxidized lignin. We studied the difference between the interactions of lignin, ammoniated lignin and ammoxidized lignin with respect to urea, based on radial distribution functions (RDFs) results from molecular dynamics (MD) simulations. Glass transition temperature (Tg) and solubility parameter (δ) of ammoniated and ammoxidized lignin have been calculated by MD simulations in the constant-temperature and constant-pressure ensemble (NPT). Molecular docking results showed the interaction sites of the urea onto the ammoniated and ammoxidized lignin and three different interaction modes were identified. Root mean square deviation (RMSD) values could indicate the mobilities of the urea molecule affected by the three different interaction modes. A series of MD simulations in the constant-temperature and constant-volume ensemble (NVT) helped us to calculate the diffusivity of urea which was affected by the content of urea in ammoniated and ammoxidized lignin.