Browsing by Author "Liu S"

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    Assessing the Dynamic Outcomes of Containment Strategies against COVID-19 under Different Public Health Governance Structures: A Comparison between Pakistan and Bangladesh
    (MDPI (Basel, Switzerland), 2022-08) Zhang W; Huggins T; Zheng W; Liu S; Du Z; Zhu H; Raza A; Tareq AH
    COVID-19 scenarios were run using an epidemiological mathematical model (system dynamics model) and counterfactual analysis to simulate the impacts of different control and containment measures on cumulative infections and deaths in Bangladesh and Pakistan. The simulations were based on national-level data concerning vaccination level, hospital capacity, and other factors, from the World Health Organization, the World Bank, and the Our World in Data web portal. These data were added to cumulative infections and death data from government agencies covering the period from 18 March 2020 to 28 February 2022. Baseline curves for Pakistan and Bangladesh were obtained using piecewise fitting with a consideration of different events against the reported data and allowing for less than 5% random errors in cumulative infections and deaths. The results indicate that Bangladesh could have achieved more reductions in each key outcome measure by shifting its initial lockdown at least five days backward, while Pakistan would have needed to extend its lockdown to achieve comparable improvements. Bangladesh’s second lockdown appears to have been better timed than Pakistan’s. There were potential benefits from starting the third lockdown two weeks earlier for Bangladesh and from combining this with the fourth lockdown or canceling the fourth lockdown altogether. Adding a two-week lockdown at the beginning of the upward slope of the second wave could have led to a more than 40 percent reduction in cumulative infections and a 35 percent reduction in cumulative deaths for both countries. However, Bangladesh’s reductions were more sensitive to the duration of the lockdown. Pakistan’s response was more constrained by medical resources, while Bangladesh’s outcomes were more sensitive to both vaccination timing and capacities. More benefits were lost when combining multiple scenarios for Bangladesh compared to the same combinations in Pakistan. Clearly, cumulative infections and deaths could have been highly impacted by adjusting the control and containment measures in both national settings. However, COVID-19 outcomes were more sensitive to adjustment interventions for the Bangladesh context. Disaggregated analyses, using a wider range of factors, may reveal several sub-national dynamics. Nonetheless, the current research demonstrates the relevance of lockdown timing adjustments and discrete adjustments to several other control and containment measures.
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    China's Changing Alcohol Market and Need for an Enhanced Policy Response: A Narrative Review
    (MDPI (Basel, Switzerland), 2022-05-11) Liu S; Huang F; Zhu X; Zhou S; Si X; Zhao Y; Liu Y; Zhang X; Casswell S; Tchounwou PB
    This study describes trends in alcohol consumption in the context of an expanding commercial context, current policy responses, and flaws in relation to international best practice for alcohol control in China. We surveyed the literature and other documents in Chinese or English up to December 2020 on policy responses to alcohol consumption and harm, industry structure, and marketing practices in China. Databases searched included PubMed, China National Knowledge Internet, Wanfang Data, Web of Science, and Baidu Scholar. We also scanned the official websites of government organizations and gathered information using snowballing. We analyzed existing alcohol policy against evidence-based, cost-effective policies for reducing alcohol harm. Our findings show that although some restrictive policies have been enacted with potential impacts on alcohol harm, they are not comprehensive, and some are poorly executed. The long history of alcohol use remains an important element in alcohol consumption by the Chinese population. However, alcohol marketing and promotion, ease of access, and affordability have become increasingly prominent. The gaps identified in alcohol policy suggest improved strategies and measures to reduce the harmful use of alcohol are urgently needed in China.
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    Decoupling of nutrient stoichiometry in Suaeda glauca (Bunge) senesced leaves under salt treatment
    (Frontiers Media S.A., 2023-09-04) Yang F; Liu S; Qian M; Wang D; Chen J; Li W
    The stoichiometry of senesced leaves is pivotal in nutrient cycling and can be significantly influenced by soil salinization, a rising global issue threatening the functionality of ecosystems. However, the impacts of soil salinization on senesced leaf stoichiometry are not fully understood. In this study, we conducted a pot experiment with varying soil salt concentrations to examine their influence on the concentrations and stoichiometric ratios of nitrogen (N), phosphorus (P), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), and zinc (Zn) in the senesced leaves of Suaeda glauca (Bunge). Compared to the control group, salt treatments significantly enhanced Na concentration while diminishing the concentrations of K, Ca, Mg, Zn, N, and P. Interestingly, as salinity levels escalated, N concentration maintained stability, whereas P concentration exhibited an increasing trend. Moreover, K, Ca, and Mg significantly declined as salt levels rose. Salt treatments brought about significant changes in stoichiometric ratios, with the N:P, K:Na, N:Na, N:Mg, and Ca : Mg ratios dropping and the N:Ca and N:K ratios rising, illustrating the varying nutrient coupling cycles under different salt conditions. These findings shed light on the plasticity of stoichiometric traits in S. glauca senesced leaves in response to soil salinization shifts, which could potentially offer insights into nutrient cycling reactions to soil salinization.
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    Experimental evolution of bacterial survival on metallic copper
    (John Wiley and Sons Ltd., 2022-08-22) Xu F; Liu S; Naren N; Li L; Ma LZ; Zhang X-X
    Antimicrobial copper-containing surface materials have a great potential of reducing the risks of healthcare-associated infections (HAIs), but their increased use in hospital facilities may select copper-resistant strains, causing concerns to antimicrobial resistance management. Here, we describe a long-term bacterial evolution experiment wherein a non-pathogenic Pseudomonas strain was subjected to daily transfer in laboratory media with and without copper-mediated contact killing. The copper treatment sequentially involved two surface materials differing in Cu content and thus contact killing effectiveness: first on brass (Cu 63.5%) and then on pure copper (Cu 99.9%). A gradual increase in bacterial survival rate (or a decrease of killing effectiveness) was observed over time on the related copper surfaces. For the final evolved populations after 320 transfers, 37.8% cells of the copper-evolved populations were able to survive 60 min on pure copper, whereas populations in the control lines remained sensitive with a survival rate of 0.09% under the same contact killing condition. Genome re-sequencing revealed ~540 mutations accumulated in the copper lines but only 71, on average, in the control lines (variant frequency > 0.5). The mutagenic activities of Cu+ ions were confirmed by measuring spontaneous mutation rate in a laboratory medium supplemented with copper sulfate at a non-inhibitory concentration. The copper-evolved populations have acquired increased resistance to Cu+ ions and tobramycin (an aminoglycoside antibiotic), but showed decreased production of biofilm, exoprotein, and pyoverdine. Together, our data demonstrate the potential of bacteria to evolve prolonged survival on metallic copper, and the long-term impacts should be considered with increased copper usage in hospital environments.
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    Prevalence and genetic diversity of Theileria equi from horses in Xinjiang Uygur Autonomous region, China.
    (Elsevier B.V., 2023-07-01) Zhang Y; Shi Q; Laven R; Li C; He W; Zheng H; Liu S; Lu M; Yang DA; Guo Q; Chahan B
    Theileria equi is a tick-borne intracellular apicomplexan protozoan parasite that causes equine theileriosis (ET). ET is an economically important disease with a worldwide distribution that significantly impacts international horse movement. Horses are an essential part of the economy in Xinjiang which is home to ∼10% of all the horses in China. However, there is very limited information on the prevalence and genetic complexity of T. equi in this region. Blood samples from 302 horses were collected from May to September 2021 in Ili, Xinjiang, and subjected to PCR examination for the presence of T. equi. In addition, a Bayesian latent class model was employed to estimate the true prevalence of T. equi, and a phylogenetic analysis was carried out based on the 18S rRNA gene of T. equi isolates. Seventy-two horses (23.8%) were PCR positive. After accounting for the imperfect PCR test using a Bayesian latent class model, the estimated true prevalence differed considerably between age groups, being 10.8% (95%CrI: 5.8% - 17.9%) in ≤ 3-year-old horses and 35.7% (95%CrI: 28.1% - 44.5%) in horses that were > 3 year-old. All T. equi isolates had their 18S rRNA gene (430bp) sequenced and analyzed in order to identify whether there were multiple genotypes of T. equi in the Xinjiang horse population. All of the 18S rRNA genes clustered into one phylogenetic group, clade E, which is thus probably the dominant genotype of T. equi in Xinjiang, China. To summarize, we monitored the prevalence of T. equi in horses of Xinjiang, China, with a focus on the association between age and the occurrence of T. equi by Bayesian modelling, accompanied by the genotyping of T. equi isolates. Obtaining the information on genotypes and age structure is significant in monitoring the spread of T. equi and studying the factors responsible for the distribution.
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    Structural Properties of Quinoa Protein Isolate: Impact of Neutral to High Alkaline Extraction pH
    (MDPI (Basel, Switzerland), 2023-07-03) Liu S; Xie Y; Li B; Li S; Yu W; Ye A; Guo Q; Tilley M
    In this work, we extracted proteins from white quinoa cultivated in the northeast of Qinghai-Tibet plateau using the method of alkaline solubilization and acid precipitation, aiming to decipher how extraction pH (7-11) influenced extractability, purity and recovery rate, composition, multi-length scale structure, and gelling properties of quinoa protein isolate (QPI). The results showed that protein extractability increased from 39 to 58% with the increment of pH from 7 to 11 whereas protein purity decreased from 89 to 82%. At pH 7-11, extraction suspensions and QPI showed the similar major bands in SDS-PAGE with more minor ones (e.g., protein fractions at > 55 or 25-37 kDa) in suspensions. Extraction pH had limited effect on the secondary structure of QPI. In contrast, the higher-order structures of QPI were significantly affected, e.g., (1) emission maximum wavelength of intrinsic fluorescence increased with extraction pH; (2) surface hydrophobicity and the absolute value of zeta-potential increased with increasing extraction pH from 7 to 9, and then markedly decreased; (3) the particle size decreased to the lowest value at pH 9 and then increased to the highest value at pH 11; and (4) denaturation temperature of QPI had a large decrease with increasing extraction pH from 7/8 to 9/10. Besides, heat-set QPI gels were formed by loosely-connected protein aggregates, which were strengthened with increasing extraction pH. This study would provide fundamental data for industrial production of quinoa protein with desired quality.