Income distribution and unequal gains from trade

This paper studies welfare gains from trade in a tractable model with a nonhomothetic preference over product quality. We show that the welfare changes due to trade shocks are unequal across consumers and derive a parsimonious formula to measure these welfare changes as in Arkolakis et al. (2012, American Economic Review, 102, 94–130). We find that the welfare changes are larger for consumers with lower income. Moreover, this paper shows that the welfare implications are different between a change in (iceberg-type) variable trade cost and a change in tariff when tariff revenue matters. More importantly, we show that the difference varies across consumers with different income levels.</p

Export quality differentiation in learning from neighbors

This paper explores how learning from neighboring firms affects new exporters’ product quality. We build a Bayesian learning model where new exporters can update their prior beliefs about the quality preference of foreign markets from their neighboring pioneering exporters. Our model shows that a new exporter raises its product quality when it receives a positive signal from its neighbors. The learning process of a firm depends on the number of neighbors, the level and heterogeneity of their export quality, and its own prior knowledge of the market. Using highly disaggregated firm-product-country-level transaction data, we find robust evidences for these predictions. Our results also suggest the impact of neighboring signals on a new exporter’s quality is channeled through the imports of high-quality intermediate inputs and more fixed investment. In addition, we find that the learning effect are heterogeneous across firms and learning can influence other aspects of export performance.</p

Export quality differentiation in learning from neighbors

This paper explores how learning from neighboring firms affects new exporters’ product quality. We build a Bayesian learning model where new exporters can update their prior beliefs about the quality preference of foreign markets from their neighboring pioneering exporters. Our model shows that a new exporter raises its product quality when it receives a positive signal from its neighbors. The learning process of a firm depends on the number of neighbors, the level and heterogeneity of their export quality, and its own prior knowledge of the market. Using highly disaggregated firm-product-country-level transaction data, we find robust evidences for these predictions. Our results also suggest the impact of neighboring signals on a new exporter’s quality is channeled through the imports of high-quality intermediate inputs and more fixed investment. In addition, we find that the learning effect are heterogeneous across firms and learning can influence other aspects of export performance.</p

The complete plastome genome sequence of <i>Cynanchum otophyllum</i> (Asclepiadaceae), a unique medicinal species in China

Cynanchum otophyllum Schneid is an important medicinal plant in China. In this paper, the chloroplast genome of C. otophyllum was sequenced based on high-throughput technology, and the chloroplast genome structure characteristics and phylogenetic relationship of C. otophyllum were analyzed. The results showed the complete plastome genome size of C. otophyllumis 160,874bp, including one small single copy (SSC, 19,851bp) and one large single copy (LSC, 92,009bp) regions isolated by a pair of inverted repeat regions (IRs, 24,507bp). The whole plastome genome including 84 protein encoding genes, 8 rRNA and 37 tRNA. Based on the phylogenetic topologies, C. otophyllum shows close association with additional Gomphocarpus and Asclepias genus. This study contributes to an enhanced understanding of the genetic information of C. otophyllum and provides a theoretical basis for the development of molecular markers and phylogeographic of the species, as well as for constructing the phylogenetic tree of Asclepiadaceae.</p

Extracellular Polymeric Substances Induced Porous Polyaniline for Enhanced Cr(VI) Removal from Wastewater

Extracellular polymeric substances (EPS) of bacteria were used as templates for synthesizing unique polyaniline nanocomposites, i.e., porous EPS-modified polyaniline (EPS@PANI). The proteins were responsible for forming porous structure, while polysaccharides for the fiber morphology of EPS@PANI. The specific surface area (53.2 m²/g) of these unique EPS@PANI with an optimal EPS loading of 2 wt % was ∼2 times larger than that of pristine PANI. The PANI in EPS@PANI stayed as the emeraldine form and acted as the electron donor for reduction of Cr­(VI) to Cr­(III). Herein, 1.0 mg/L Cr­(VI) was completely reduced to Cr­(III) by 600 mg/L of EPS@PANI within 10 min, which was much faster than the pristine PANI (1 h). A maximum Cr­(VI) removal capacity of 913.2 mg/g was achieved by these unique EPS@PANI nanocomposites and was ∼4.7 times higher than the pristine PANI (193.8 mg/g). Moreover, the isoelectric point (pI) was decreased from pH 7.5 for pure PANI to ∼4.5 for these porous EPS@PANI nanocomposites due to the low pI of polysaccharides remained in the composites. This lowered pI facilitated further Cr­(III) removal on the surface of EPS@PANI from the wastewater

Gold Nanorods as Colorful Chromogenic Substrates for Semiquantitative Detection of Nucleic Acids, Proteins, and Small Molecules with the Naked Eye

Herein, we report for the first time a colorful chromogenic substrate, which displays vivid color responses in the presence of different concentration of analytes. Our investigation reveals that the selective shortening of gold nanorods (AuNRs) could generate a series of distinct colors that covers nearly the whole visible range from 400 to 760 nm. These vivid colors can be easily distinguished by the naked eye; as a result, the accuracy of visual inspection could be greatly improved. Next, we demonstrate the utility of AuNRs as multicolor chromogenic substrate to develop a number of colorimetric immunoassay methods, e.g., multicolor enzyme-linked immunosorbent assay (ELISA), multicolor competitive ELISA, and multicolor magnetic immunoassay (MIA). These methods allow us to visually quantify the concentration of a broad range of target molecules with the naked eye, and the obtained results are highly consistent with those state-of-the-art techniques that are tested by the sophisticated apparatus. These multicolor portable and cost-effective immunoassay approaches could be potentially useful for a number of applications, for example, in-home personal healthcare, on-site environmental monitoring, and food inspection in the field

Enantioselective Epoxidation of Olefins with H₂O₂ Catalyzed by Bioinspired Aminopyridine Manganese Complexes

A novel family of bioinspired manganese­(II) complexes bearing chiral aminopyridine ligands that possessed additional aromatic groups and strong donating dimethylamino groups were synthesized and characterized. These manganese complexes exhibited efficient and improved activities in the asymmetric epoxidation of various olefins, such as styrene derivatives (up to 93% ee) with H₂O₂ as the oxidant, even with a catalytic amount of carboxylic acid as the additive

Nanostructured Electrode Materials Derived from Metal–Organic Framework Xerogels for High-Energy-Density Asymmetric Supercapacitor

This work successfully demonstrates metal–organic framework (MOF) derived strategy to prepare nanoporous carbon (NPC) with or without Fe₃O₄/Fe nanoparticles by the optimization of calcination temperature as highly active electrode materials for asymmetric supercapacitors (ASC). The nanostructured Fe₃O₄/Fe/C hybrid shows high specific capacitance of 600 F/g at a current density of 1 A/g and excellent capacitance retention up to 500 F/g at 8 A/g. Furthermore, hierarchically NPC with high surface area also obtained from MOF gels displays excellent electrochemical performance of 272 F/g at 2 mV/s. Considering practical applications, aqueous ASC (aASC) was also assembled, which shows high energy density of 17.496 Wh/kg at the power density of 388.8 W/kg. The high energy density and excellent capacity retention of the developed materials show great promise for the practical utilization of these energy storage devices

Photoelectrochemical Sensor for H₂S Based on a Lead-Free Perovskite/Metal–Organic Framework Composite

Halide perovskites have emerged as a highly promising class of photoelectric materials. However, the application of lead-based perovskites has been hindered by their toxicity and relatively weak stability. In this work, a composite material comprising a lead-free perovskite cesium copper iodide (CsCu2I3) nanocrystal and a metal–organic framework (MOF-801) has been synthesized through an in situ growth approach. The resulting composite material, denoted as CsCu2I3/MOF-801, demonstrates outstanding stability and exceptional optoelectronic characteristics. MOF-801 may serve a dual role by acting as a protective barrier between CsCu2I3 nanocrystals and the external environment, as well as promoting the efficient transfer of photogenerated charge carriers, thereby mitigating their recombination. Consequently, CsCu2I3/MOF-801 demonstrates its utility by providing both stability and a notably high initial photocurrent. Leveraging the inherent reactivity between H2S and the composite material, which results in the formation of Cu2S and structural alteration, an exceptionally sensitive photoelectrochemical sensor for H2S detection has been designed. This sensor exhibits a linear detection range spanning from 0.005 to 100 μM with a remarkable detection limit of 1.67 nM, rendering it highly suitable for precise quantification of H2S in rat brains. This eco-friendly sensor significantly broadens the application horizon of perovskite materials and lays a robust foundation for their future commercialization

Label-Free Fluorometric Method for Monitoring Conformational Flexibility of Laccase Based on a Selective Laccase Sensor

A facile and selective fluorescence sensor for laccase determination has been proposed depending on the interaction between 3-azidocoumarin and trametes versicolor (Tv) laccase in this paper. The azido group of 3-azidocoumarin that is electron-rich α-nitrogen can directly interact with histidines that coordinate to three copper sites through hydrogen bonds and forms a new complex, which decreases the electron-donating ability of the azido group, leading to enhance the fluorescence intensity of the sensing system. Also, other common proteins have no significant interference for the proposed laccase sensor. Additionally, the proposed fluorescence sensor is extended to demonstrate the conformational flexibility of Tv laccase by the urea denaturant. A good consistency of the results obtained with the presented laccase sensor and CD spectra is performed. Furthermore, the relationship between the catalytic activity and the unfolding percentage of the unfolded Tv laccase through the proposed laccase sensor is also elucidated well