Alcoholysis of Furfuryl Alcohol to Ethyl Levulinate Catalyzed by a Deep Eutectic Solvent

In this study, the alcoholysis of furfuryl alcohol (FA) into ethyl levulinate (EL) using a deep eutectic solvent (DES) composed of choline chloride (ChCl) and ethanol was investigated by experiments and calculations. Experimental results reveal that the addition of 5-sulfonic acid salicylic acid (5-SSA) can catalyze the alcoholysis of FA to produce EL. The combined presence of ChCl and 5-SSA significantly improved the selectivity for EL. The mechanism of the alcoholysis of FA to EL in acidic DES was investigated by density functional theory (DFT) calculations in Gaussian 03. It was found that hydrogen-bond acceptor ChCl is coupled with hydrogen-bond donor ethanol to form a structure similar to HCl and ethoxy, which facilitates the alcoholysis of FA into EL

High-Density N‑Vacancy-Induced Multipath Electrochemiluminescence Improvement of 3D g‑C₃N₄ for Ultrasensitive MiRNA-222 Analysis

Using dissolved O2 as the cathodic co-reactant of three-dimensional (3D) g-C3N4 is a convenient method to improve the electrochemiluminescence (ECL) signal, but it still suffers the disadvantages of limited luminous efficiency of 3D g-C3N4 and low content, low reactivity, and instability of dissolved O2. Here, N vacancy with high density was first introduced into the structure of 3D g-C3N4 (3D g-C3N4-NV), which could conveniently realize multipath ECL improvement by simultaneously solving the above shortcomings effectively. Specifically, N vacancy could change the electronic structure of 3D g-C3N4 to broaden its band gap, increase fluorescence (FL) lifetime, and accelerate electron transfer rate, obviously improving the luminous efficiency of 3D g-C3N4. Meanwhile, N vacancy made the excitation potential of 3D g-C3N4-NV to shift from −1.3 to −0.6 V, effectively weakening the electrode passivation. Moreover, the adsorption capacity of 3D g-C3N4-NV was obviously enhanced, which could make the dissolved O2 enrich around 3D g-C3N4-NV. And massive active NV sites of 3D g-C3N4-NV could promote O2 to more efficiently convert to reactive oxygen species (ROS) that were key intermediates in ECL generation. Using the newly proposed 3D g-C3N4-NV-dissolved O2 system as an ECL emitter, an ultrasensitive target conversion biosensor was constructed for miRNA-222 detection. The fabricated ECL biosensor exhibited satisfactory analytical performance for miRNA-222 with a detection limit of 16.6 aM. The strategy achieved multipath ECL improvement by introducing high-density N vacancy simply in the 3D structure of g-C3N4 and could open a new horizon for developing a high-performance ECL system

An urban cellular automata model based on a spatiotemporal non-stationary neighborhood

Spatiotemporal modeling has long been a major concern of geographic information science. Even though previous research has shown the importance of temporal and spatial information in quantifying the neighborhood effects of urban cellular automata (CA) models, constructing a spatiotemporal non-stationary neighborhood remains a challenge, due to the complexity of the spatiotemporal models. In this study, we introduced spatiotemporal modeling into the neighborhood of an urban CA model and constructed a geographically and temporally weighted neighborhood (GTWN). A corresponding approach to optimizing the bandwidth of the GTWN was also developed. Taking Beijing and Wuhan in China as examples, the GTWN-CA model was employed to simulate their urban expansion. The experimental results indicate that the GTWN-CA model has a better and performance than other CA models whose neighborhood is constructed based on the assumption of temporal or spatial stationarity, highlighting the advantages of spatiotemporal modeling in quantifying the neighborhood effect. Compared with the commonly used CA model with a homogeneous neighborhood (HON-CA), in terms of the figure of merit (FoM), the calibration accuracy of the GTWN-CA model was improved by 0.87% in Beijing and 5.4% in Wuhan, and the validation accuracy was improved by 7.9% in Beijing and 8.9% in Wuhan.</p

Supplemental Material - A hybrid modeling approach considering spatial heterogeneity and nonlinearity to discover the transition rules of urban cellular automata models

Supplemental Material for A hybrid modeling approach considering spatial heterogeneity and nonlinearity to discover the transition rules of Urban cellular automata models by Haoran Zeng, Bin Zhang and Haijun Wang in Environment and Planning B: Urban Analytics and City Science.</p

Mechanochemical Model of the Power Stroke of the Single-Headed Motor Protein KIF1A

During the process of ATP binding to an apo-kinesin microtubule (MT), the kinesin core rotates on the MT, and the neck linker (NL) of the kinesin undergoes an undocked to docked transition. This has been suggested to be a power stroke of kinesin, on the basis of the structural analysis. Here, we developed a mesoscopic structure-based model and studied the power stroke of KIF1A. We quantified the underlying free energy landscape and showed the emergence of several states for the power stroke of KIF1A: UB-UR-UD (unbound, unrotating, undock), B-IR-UD (bound, initial rotating, undock), B-PR-UD (bound, partial rotating, undock), and B-R-D (bound, rotating, dock). We found that ATP binding triggered conformational fluctuations of key elements. We also explored the conformational change of key structural elements during the rotation of KIF1A and docking of the NL. In addition, we semiquantitatively and qualitatively estimated the free energy released by the ATP binding, and how much of this remains for the docking of the NL during the power stroke process at different temperatures. Finally, based on results from the thermodynamics landscape and conformational change of structural key elements, we proposed a mechanochemical model of the power stroke of KIF1A

The results of difference-in-difference analyses (DID) for indicators of economic status between affected and comparison households (Mean, US $).

<p>Affected group: households with a maternal death; Comparison group: matched households without maternal death.</p>a<p>Δ_affected refers to the mean value of affected group in follow-up minus that at baseline.</p>b<p>Δ_comparison refers to the mean value of comparison group in follow-up minus that at baseline.</p>c<p>Numbers in parentheses are <i>P</i>-value.</p>d<p>1 score for each item with answer “have”, 0 score for each item with answer “don't have”. All 5 items were summed up. The items included (1) TV, (2) Cable TV, (3) Telephone, (4) Motorcycle, electrobicycle, or elctrotricycle, (5) Truck, tricar, or tractor.</p>e<p>All 3 items were summed up. The items included (1) How many pigs are there in your family? (2) How many sheep is there in your family? (3) How many other live stocks are there in your family, such as cattle, horse, donkey, mule, etc?</p>f<p>1 score for each item with answer “yes”, 0 score for each item with answer “no”. All 6 items were summed up. The items included (1) Can your family have enough food to be not hungry? (2) Can your family eat meat, egg, or fish at least once every week? (3) Can your family buy enough clothes to keep warm in winter? (4) Can your family buy a piece of new clothes? (5) Can your family members go to the hospital when having indisposition? (6) Can your family buy some daily necessaries (e.g. Toilet paper, shampoo, soap, washing powder, etc)?</p

Effect of Linear-Hyperbranched Amphiphilic Phosphate Esters on Collagen Fibers

The surfactants of the linear-hyperbranched phosphate esters (PAMAMGn-3-Ps) have been constructed through random multibranching esterification of lauroyl chloride and phosphate ester as a branching agent. Subsequently, a series of surfactant products were obtained. Benefiting from the amphiphilic structure with the hydrophilic core and many hydrophobic tails, PAMAMGn-3-Ps were able to self-assemble into nanomicelles in aqueous media. Importantly, the polymers show low critical micelle concentrations (CMCs) and small particle sizes. Here, PAMAMG1-3-P was applied in the collagen fibers of leather to improve the fibers’ distance and mechanical property of collagen fibers. Additionally, the polymers display significant flexibility, which could replace ordinary fatliquor in the future. The result provides a new application of using linear-hyperbranched amphiphilic phosphate esters into traditional leather materials to enhance the performance of collagen fibers

Stratification results of difference-in-difference analyses (DID) for indicators of economic status between affected households with newborn survived or not and comparison households (Mean, US $).

<p>Affected group: households with a maternal death; Comparison group: matched households without maternal death.</p>a<p>Δ_affected refers to the mean value of affected group in follow-up minus that at baseline.</p>b<p>Δ_comparison refers to the mean value of comparison group in follow-up minus that at baseline.</p>c<p>Numbers in parentheses are <i>P</i>-value.</p>d<p>1 score for each item with answer “have”, 0 score for each item with answer “don't have”. All 5 items were summed up. The items included (1) TV, (2) Cable TV, (3) Telephone, (4) Motorcycle, electrobicycle, or elctrotricycle, (5) Truck, tricar, or tractor.</p>e<p>All 3 items were summed up. The items included (1) How many pigs are there in your family? (2) How many sheep is there in your family? (3) How many other live stocks are there in your family, such as cattle, horse, donkey, mule, etc?</p>f<p>1 score for each item with answer “yes”, 0 score for each item with answer “no”. All 6 items were summed up. The items included (1) Can your family have enough food to be not hungry? (2) Can your family eat meat, egg, or fish at least once every week? (3) Can your family buy enough clothes to keep warm in winter? (4) Can your family buy a piece of new clothes? (5) Can your family members go to the hospital when having indisposition? (6) Can your family buy some daily necessaries (e.g. Toilet paper, shampoo, soap, washing powder, etc)?</p

Categories of annual income and expenditure at individual level (Mean, US $).

<p>Affected group: households with a maternal death; Comparison group: matched households without maternal death; DID: Difference-in-difference analyses.</p>a<p>Δ_affected refers to the mean value of affected group in follow-up minus that at baseline.</p>b<p>Δ_comparison refers to the mean value of comparison group in follow-up minus that at baseline.</p>c<p>Numbers in parentheses are <i>P</i>-value.</p

Demographic profile of the affected and comparison groups at baseline survey.

<p>Affected group: households with a maternal death; Comparison group: matched households without maternal death; SD: Standard Deviation.</p>a<p>Primiparas refers to a woman who has given birth once.</p>b<p>In China, “minority” means non-Han ethnicity, including Hui, Yi, Hani, etc.</p>c<p>Dependency ratio is the ratio of dependent part (number of those under the age of 15 and over the age of 64 in the household) to productive part (number of those ages between 15–64 in the household).</p