VO_<i>x</i> Core–Shell Catalysts for One-Pot Oxidation and Separation of Refractory Multiaromatic Sulfur Compounds in a Model Diesel

Ti-MCM-41 supported vanadia core–shell catalysts were prepared and their catalytic activity was evaluated in a biphasic reactor for simultaneous oxidation/separation of refractory organosulfur compounds (dibenzothiophene (DBT), 4-methyldibenzo­thiophene (4-MDBT), and 4,6-dimethyldibenzo­thiophene (4,6-DMDBT)) in a model diesel fuel. Formation of core–shell structure in the catalyst nanoparticles resulted from the surface diffusion of the vanadium ion in semimelted state of vanadia during the calcination process. It was found that both the value of V⁵⁺/(V⁴⁺ + V⁵⁺) and the surface acidity of the catalysts generally increased as the content of V content increased to 15 wt % of vanadium and correlated well with variations in catalytic activity, indicating that the surface V⁵⁺ and surface acid sites were chiefly responsible for the oxidation of sulfur compounds. The reactivity of organosulfur compounds was influenced by their steric hindrance. Addition of carboxylic acid (acetic acid or formic acid) promoted the sulfur oxidation efficiency via formation of more stable and active oxygen species like peroxometallic and superoxometallic species on the catalyst surface. Approximately 99% of the sulfur compounds were removed with the best catalysts containing 15 wt % V at a reaction temperature of 60 °C and within 60 min. This one-pot organosulfur oxidation and separation method was proven to be efficient, economical, and practical for deep desulfurization of diesel fuels containing refractory organosulfur compounds

Predicting and Evaluating the Epidemic Trend of Ebola Virus Disease in the 2014-2015 Outbreak and the Effects of Intervention Measures

<div><p>We constructed dynamic Ebola virus disease (EVD) transmission models to predict epidemic trends and evaluate intervention measure efficacy following the 2014 EVD epidemic in West Africa. We estimated the effective vaccination rate for the population, with basic reproduction number (<i>R</i>₀) as the intermediate variable. Periodic EVD fluctuation was analyzed by solving a Jacobian matrix of differential equations based on a SIR (susceptible, infective, and removed) model. A comprehensive compartment model was constructed to fit and predict EVD transmission patterns, and to evaluate the effects of control and prevention measures. Effective EVD vaccination rates were estimated to be 42% (31–50%), 45% (42–48%), and 51% (44–56%) among susceptible individuals in Guinea, Liberia and Sierra Leone, respectively. In the absence of control measures, there would be rapid mortality in these three countries, and an EVD epidemic would be likely recur in 2035, and then again 8~9 years later. Oscillation intervals would shorten and outbreak severity would decrease until the periodicity reached ~5.3 years. Measures that reduced the spread of EVD included: early diagnosis, treatment in isolation, isolating/monitoring close contacts, timely corpse removal, post-recovery condom use, and preventing or quarantining imported cases. EVD may re-emerge within two decades without control and prevention measures. Mass vaccination campaigns and control and prevention measures should be instituted to prevent future EVD epidemics.</p></div

Periodical low dampened oscillation of <i>s</i> and <i>i</i> around the dynamic equilibrium point.

<p>The proportions of EVD cases (left y-axis) and susceptible people (right y-axis), compared to the total population, are shown as functions of time in years. In the absence of control and prevention measures, the <i>s</i> and <i>i</i> values would oscillate periodically around their dynamic equilibrium points. Meanwhile, periods between oscillations would shorten, and amplitudes would decrease gradually.</p

Compartment transfer block diagram of the transmission dynamic model.

<p>(A) Compartment transfer block diagram of the SIR model. Blocks <i>S</i>, <i>I</i>, and <i>R</i> represent susceptible individuals, symptomatic patients, and people with immunity owing to recovery, respectively. <i>β</i> is the standard contact rate, indicating the number of people infected by the same patient per unit time in a population of entirely susceptible persons. <i>α</i> and <i>γ</i> denote the probability of one patient dying or recovering per unit time, respectively. <i>b</i> and <i>d</i> are the population’s birth and mortality rates per unit time, respectively. (B) Comprehensive compartment transfer block diagram of EVD epidemiology. Blocks <i>S</i>, <i>E</i>, <i>I</i>, and <i>D</i> represent susceptible persons in a free environment, infected individuals in the incubation period, patients in a free environment, and not-yet-decontaminated corpses of EVD patients, respectively. Blocks <i>U</i>, <i>P</i>, and <i>Q</i> denote suspected cases in isolation, confirmed cases in isolation, and close contacts in isolation, respectively. Blocks <i>H</i>, <i>R</i>, <i>K</i>, and <i>A</i> indicate the medical staff in charge of <i>U</i> and <i>P</i>, recovered patients that are still infectious, recovered individuals that are not infectious and with immunity, and imported cases per day, respectively.</p

Comparison of the numbers of EVD cases and deaths predicted by the model to those published by the WHO.

<p>The cumulative number of EVD cases and deaths are plotted as a function of time <i>t</i> in months. The cumulative number of cases predicted curve (blue) includes confirmed and suspected cases. Each red point indicates the number of cumulative cases (blue curve) or deaths due to EVD (green curve) published by the WHO.</p

Values, ranges and data sources of all parameters in models in Fig 6A and 6B.

<p>Values, ranges and data sources of all parameters in models in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0152438#pone.0152438.g006" target="_blank">Fig 6A and 6B</a>.</p

Effects of control and prevention measures on EVD epidemic trends.

<p>(A) Summary of the effect of isolating EVD patients’ close contacts on the cumulative number of EVD cases. Note the markedly lower curve with close contact quarantine (red) relative to that without close contact quarantine (blue). (B) Predicted numbers of cumulative EVD cases when corpses of dead EVD patients were allowed to stay in the surrounding environment for 3 (blue), 2 (green), 1 (red), or 0.5 days (yellow). (C) Predicted new EVD cases when the average symptom onset-to-isolation and treatment is 5 days (blue), 4 days (green), and 3 days (red). (D) Predicted reduction in the number of new EVD cases from August 1^st, 2014 to May 31^st, 2015 when recovered patients have condom-protected (red) versus unprotected (green) sex. (E) Summary of the effect of cases being imported from other countries on the epidemic trend of EVD. Note that introduction of a new case every other day (0.5 cases/day, green) has a strong effect on amplitude relative to zero case importation (red). In all panels, the number of predicted EVD cases is plotted as a function of time.</p

Effects of EVD on total population and EVD case number in the absence of control and prevention measures.

<p>Changes in the total number of individuals in the population and in the number of EVD cases in Guinea (A, B), Liberia (C, D), and Sierra Leone (E, F) are shown. The x-axes indicate time in months, and the y-axes indicate population number or the number of EVD cases. The shaded area indicates the 95% confidence interval.</p

Metatranscriptome Revealed the Efficacy and Safety of a Prospective Approach for Agricultural Wastewater Reuse: Achieving Ammonia Retention during Biological Treatment by a Novel Natural Inhibitor Epsilon-Poly‑l‑Lysine

Appropriate inhibitors might play important roles in achieving ammonia retention in biological wastewater treatment and its reuse in agriculture. In this study, the feasibility of epsilon-poly-l-lysine (ε-PL) as a novel natural ammonia oxidation inhibitor was investigated. Significant inhibition (ammonia oxidation inhibition rate was up to 96.83%) was achieved by treating the sludge with ε-PL (400 mg/L, 12 h soaking) only once and maintaining for six cycles. Meanwhile, the organic matter and nitrite removal was not affected. This method was effective under the common environmental conditions of biological wastewater treatment. Metatranscriptome uncovered the possible action mechanisms of ε-PL. The ammonia oxidation inhibition was due to the co-decrease of Nitrosomonas abundance, ammonia oxidation genes, and the cellular responses of Nitrosomonas. Thauera and Dechloromonas could adapt to ε-PL by stimulating stress responses, which maintained the organic matter and nitrite removal. Importantly, ε-PL did not cause the enhancement of antibiotic resistance genes and virulent factors. Therefore, ε-PL showed a great potential of ammonia retention, which could be applied in the biological treatment of wastewater for agricultural reuse

Table_1_Size measurement and filled/unfilled detection of rice grains using backlight image processing.docx

Measurements of rice physical traits, such as length, width, and percentage of filled/unfilled grains, are essential steps of rice breeding. A new approach for measuring the physical traits of rice grains for breeding purposes was presented in this study, utilizing image processing techniques. Backlight photography was used to capture a grayscale image of a group of rice grains, which was then analyzed using a clustering algorithm to differentiate between filled and unfilled grains based on their grayscale values. The impact of backlight intensity on the accuracy of the method was also investigated. The results show that the proposed method has excellent accuracy and high efficiency. The mean absolute percentage error of the method was 0.24% and 1.36% in calculating the total number of grain particles and distinguishing the number of filled grains, respectively. The grain size was also measured with a little margin of error. The mean absolute percentage error of grain length measurement was 1.11%, while the measurement error of grain width was 4.03%. The method was found to be highly accurate, non-destructive, and cost-effective when compared to conventional methods, making it a promising approach for characterizing physical traits for crop breeding.</p