US-China health exchange and collaboration following COVID-19.

Strong US-China collaboration on health and medicine is a crucial element of the global effort against COVID-19. We review the history of health collaboration and exchanges between the public and private sectors in the USA and China, including the long-lasting collaboration between governmental public health agencies of the two countries. Academic and scientific exchanges should be reinvigorated and the increasing valuable role of non-profit foundations acknowledged. The shared interests of the two countries and the magnitude of the pandemic necessitate both countries to collaborate and cooperate. We provide recommendations to the two governments and the global health community to control the ongoing COVID-19 pandemic and prepare for future threats. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

Metal-Organic-Framework-Derived Atomically Dispersed Mn-N-C Electrocatalysts Boosting Oxygen Reduction Modulated by Anion Exchange of Permanganate.

Mn-N-C materials have received increasing interest in recent years because of their low Fenton reactivity and ORR activity comparable to those of their Fe-N-C and Co-N-C counterparts. In this contribution, an atomically dispersed Mn-N-C electrocatalyst with a prominent oxygen reduction performance was constructed by employing a cationic Cd-MOF as a precursor that can facilely and accurately introduce MnO4- anions through anion exchange. The best-performing Mn-N-C catalyst displays a 0.96 V (vs RHE) Eonset (onset potential) and a 0.87 V (vs RHE) E1/2 (half-wave potential) in an alkaline solution, which exceed those of the benchmark Pt/C catalyst. In particular, the maximal power density of the self-made zinc-air battery reaches 200 mW·cm-2, surpassing that of most reported Mn-N-C materials.

Effects of continuous cucumber cropping on crop quality and soil fungal community.

Long-term continuous cropping is a common practice in facility vegetable production, which has an adverse effect on cucumber yield and quality. Soil fungi are of great significance for creating a normal soil ecological environment. However, the impact of continuous cropping on cucumber quality and soil fungal community has yet to be understood. In this study, we evaluated the effects of continuous cropping on cucumber using high-throughput sequencing technology. The results showed that the extension of continuous cropping would increase nitrate and total acidity of cucumber, while the contents of vitamin C (VC), soluble sugar, and protein were decreased. The increase of continuous cropping duration also reduced the fungal diversity of the cucumber soil. For example, the activity of three dominant fungal phylums, Ascomycota, Aphelidiomycota, and Basidiomycota, decreased with the extension of planting years. The relative abundance of the two fungi species (Remersonia_thermophila, Mortierella_oligospora) was negatively correlated with the contents of available phosphorus and available potassium (P < 0.05). Redundancy analysis (RDA) found that soil electrical conductivity (EC), available phosphorus (AP), and pH accounted for the top three major factors of fungal community structure changes. The soil fungal community was changed during the continuous cucumber cultivation, which might be the result of the combined cultivation period of cucumber and excessive application of chemical fertilizers (nitrogen fertilizer, phosphate fertilizer, etc.). Our study provides a theoretical basis for the understanding of the impact of continuous cropping in cucumber facilities.

Effects of exogenous sulfur on maize (Zea mays L.) growth and Cd accumulation in Cd-contaminated plastic shed soil.

Cadmium (Cd) pollution in plastic shed soils has become increasingly severe, posing a great threat to human health and social stability. Phytoremediation of cadmium pollution is an environmentally friendly and inexpensive remediation method. In this study, maize (Zea mays L.) was selected as the phytoremediation crop by a potted method, and the bioavailability of cadmium was investigated by adding exogenous elemental sulfur. The relationships among the sulfur content, maize growth, cadmium accumulation, and soil parameters were systematically studied. The results showed that, with the supplement of sulfur, the soil pH and activities of soil enzymes (urease, catalase, and sucrase) decreased gradually, and the available heavy metals (Cd, Cr, Zn, and Cu) in soil showed an upward trend. The optimal cadmium enrichment was achieved under T2 by increasing both the biomass of the maize plant and the cadmium concentration in roots and stems. However, T3 and T4 significantly inhibited the growth of maize roots and shoots, leading to a much lower plant biomass compared with that of CK (sulfur-free treatment) and T2. In addition, the cumulative cadmium was not increased because of the low accumulation of cadmium in some parts of the plant. Correlation analyses showed that the sulfur content was negatively correlated with soil pH and maize biomass (P < 0.01), and the cadmium content of whole maize was positively correlated with the dry weight of maize (P < 0.05) and the cadmium content in roots and stems (P < 0.01). In summary, to optimize cadmium phytoremediation of the plastic shed soil, an appropriate concentration of sulfur should be selected in practical applications to ensure that the biomass of the maize is maximized, and the cadmium concentration in different parts of the maize is increased or stabilized.

Heavy metal and soil nutrient accumulation and ecological risk assessment of vegetable fields in representative facilities in Shandong Province, China.

Shandong is one of the main areas for protected vegetable cultivation in China. A total of 88.5% of the facility soil samples had a pH between 7.0 and 8.4, indicating the majority of the soils were alkaline. Key properties, including total nitrogen (TN), organic matter (OM), electrical conductivity (EC), available phosphorus (AP), and available potassium (AK), showed an increasing trend with the number of years. The geoaccumulation index (Igeo) indicated that the Cd and Hg contents ranged from uncontaminated to moderate contaminated, while the risk of Hg and Cd reached the class of considerable risk as indicated by the potential ecological risk factor ([Formula: see text]). The mean of Hakanson potential ecological risk index (RI) was 234.00, with the highest contribution from Hg (55.26%), followed by Cd (38.81%). It indicated that the survey area was at the moderate-risk level and Hg had the highest potential ecological risk factor, followed by Cd.

Carbon Nanomaterials for Plant Priming through Mechanostimulation: Emphasizing the Role of Shape.

The use of nanomaterials to improve plant immunity for sustainable agriculture is gaining increasing attention; yet, the mechanisms involved remain unclear. In contrast to metal-based counterparts, carbon-based nanomaterials do not release components. Determining how these carbon-based nanomaterials strengthen the resistance of plants to diseases is essential as well as whether shape influences this process. Our study compared single-walled carbon nanotubes (SWNTs) and graphene oxide (GO) infiltration against the phytopathogen Pseudomonas syringae pv tomato DC3000. Compared with plants treated with GO, plants primed with SWNTs showed a 29% improvement in the pathogen resistance. Upon nanopriming, the plant displayed wound signaling with transcriptional regulation similar to that observed under brushing-induced mechanostimulation. Compared with GO, SWNTs penetrated more greatly into the leaf and improved transport, resulting in a heightened wound response; this effect resulted from the tubular structure of SWNTs, which differed from the planar form of GO. The shape effect was further demonstrated by wrapping SWNTs with bovine serum albumin, which masked the sharp edges of SWNTs and resulted in a significant decrease in the overall plant wound response. Finally, we clarified how the local wound response led to systemic immunity through increased calcium ion signaling in distant plant areas, which increased the antimicrobial efficacy. In summary, our systematic investigation established connections among carbon nanomaterial priming, mechanostimulation, and wound response, revealing recognition patterns in plant immunity. These findings promise to advance nanotechnology in sustainable agriculture by strengthening plant defenses, enhancing resilience, and reducing reliance on traditional chemicals.

Anodic Oxidation of Methanol to Formaldehyde Synergizing with a Br-/Br2 Redox-Mediated Chemical Route to Produce Methyl Formate.

Methyl formate (MF) is one of the most important chemical commodities, which has a wide range of applications. Due to environmental friendliness, mild reaction conditions, and easy operations, electrosynthesis of MF has garnered increasing attention in recent years. In this work, we reported an electrosynthesis route toward MF in a halide-containing methanol solution. The thorough mechanistic investigations point out that electrosynthesis of MF is accomplished by instant reaction between aldehyde from anodic methanol oxidation, and methoxy bromide (CH3OBr) that is in-situ generated by reaction of Br2 from anodic oxidation of Br- with methoxide (CH3O-) from cathodic reduction of methanol. This method features high atomic economy only producing valuable MF and hydrogen gas, and shows distinct advantages compared to the reported MF electrosynthesis methods. Even at 200 mA/cm2, the faradaic efficiency (FE) of MF remains consistently around 60 % at the anode while a 100 % FE hydrogen gas is produced at the cathode.

Iodide ion-imprinted chitosan beads for highly selective adsorption for nuclear wastewater treatment applications.

Iodide ions from radioactive iodine isotopes are common contaminants present in nuclear wastewater from nuclear power plants which are considered hazardous contaminants to be released in water sources even at low concentrations due to their association with metabolic disorders, therefore its removal from the nuclear wastewater effluents is necessary. Chitosan beads are natural and cost-efficient adsorbents that have been used for ion removal from wastewater. However, issues of poor selectivity persist in achieving high-efficiency iodide ion removal. In this study, ion-imprinted chitosan beads (IIC) have been synthesized using the phase-inversion method, IIC beads were modified by cross-linking with epichlorohydrin (IIC-EPI) and modified by cross-linking with epichlorohydrin and silicon dioxide nanoparticles (IIC-SiO2-EPI). Through 4 h of batch adsorption experiments, IIC beads achieved a maximum adsorption capacity (Qe) of 0.65 mmol g-1 and showed more preference for the iodide ions compared to the non-imprinted chitosan beads which achieved a maximum adsorption capacity of 0.27 mmol g-1 at pH 7. While the modified beads IIC-EPI and IIC-SiO2-EPI beads have boosted the adsorption capacities to 0.72 mmol g-1 and 0.91 mmol g-1. Scanning electron microscopic cross-sectional images have shown more pores and cavities than the surface images which agrees with the multilayer heterogeneous diffusion suggested by the Freundlich adsorption isotherm, that the experimental data has fitted. Adsorption kinetic data have fitted the Pseudo-second-order model as well as the Weber and Morris intraparticle model, which suggest an intraparticle pore diffusion adsorption mechanism, with the involvement of the physical electrostatic interactions with the cationic chitosan surface.

Synergistic effects of CuS/TiO2 heterointerfaces: Enhanced cathodic CO2 reduction and anodic CH3OH oxidation for paired electrosynthesis of formate.

The electrochemical reduction of carbon dioxide into energy-carrying compounds or value-added chemicals is of great significance for diminishing the greenhouse effect. However, it is still imperative to replace the less-value anodic oxygen evolution reaction (OER) to improve the technical economy. Herein, we firstly reported a bifunctional CuS/TiO2 catalyst for both anodic methanol oxidation reaction (MOR) and cathodic carbon dioxide reduction (CO2R). The in-built abundant CuS/TiO2 heterointerfaces are found to boost the CO2R and MOR to produce formate. Based on the unique bifunctionality of CuS/TiO2, a paired electrosynthesis of formate was performed with a total Faradaic efficiency (FE) of about 170 %, in which the cathodic CO2R achieved a formate FE of about 70 %, and the anodic MOR exhibited an almost 100 % formate FE.

Zn(II)-MOF derived N-doped carbons achieve marked ORR activity in alkaline and acidic media.

A highly efficient metal-free N-doped carbon electrocatalyst toward oxygen reduction was obtained by one-pot pyrolysis of a single Zn(II)-MOF with mixed azolate and terephthalate ligands, demonstrating E1/2 of 0.88 V (vs. RHE) in 0.1 M KOH, and 0.79 V (vs. RHE) in 0.5 M H2SO4. It represents one of the best metal-free N-doped carbon electrocatalysts for the acidic ORR.

The separation of oily water using low-cost natural materials: Review and development.

This paper reviewed the recent progress on a number of important natural/biomass materials (fibers, leaves, woods, nutshells, algae, and sands, etc.) for the separation of oily water mixture/emulsions. Experiments were conducted with desert pristine sand samples, which were collected, sieved, characterized and tested for the separation of two surfactant-stabilized oil in water (O/W) emulsions in a simple cross-flow sand bed filter under the simulated natural gravity. The wettability of the sand samples was checked through contact angle measurements. The morphology of sands was characterized with SEM/EDX and FTIR. Experimental results revealed that natural sand filtration is a promising technology with the characteristics of: 1) a surface of superhydrophilicity and underwater superoleophobicity; 2) sands bed achieved separation efficiency and flux comparable or higher than commercial microfiltration membranes under natural gravity conditions, and 3) the separation efficiency and flux of the sand bed are relatively stable with respect to the operation parameters. This technology is technically feasible, low-cost, and environmental-benign and can play an important role in the practical applications.

Melatonin Participates in Selenium-Enhanced Cold Tolerance of Cucumber Seedlings.

Melatonin is an important and widespread plant hormone. However, the underlying physiological and molecular mechanisms of melatonin as a secondary messenger in improving cold tolerance by selenium are limited. This study investigated the effects of selenite on the cold stress of cucumber seedlings. The results showed that exogenous application of selenite improved the cold tolerance of cucumber seedlings, which was dependent on the concentration effect. In the present experiment, 1 µM of selenite showed the best effect on alleviating cold stress. Interestingly, we found that in the process of alleviating cold stress, selenite increased the content of endogenous melatonin by regulating the expression of melatonin biosynthesis genes (TDC, T5H, SNAT, and COMT). To determine the interrelation between selenite and melatonin in alleviating cold stress, melatonin synthesis inhibitor p-chlorophenylalanine and melatonin were used for in-depth study. This study provides a theoretical basis for cucumber cultivation and breeding.

[Effects of different forms of microbial agents on the growth and quality of Brassica rapa L. ssp. chinensis Makino (non-heading Chinese cabbage).] / 不同形态微生物菌剂对不结球白菜生长和品质的影响.

Reasonable application of microbial agents can significantly improve soil environment and increase the yield and quality of vegetables. In this study, we examined the effects of different forms of microbial agents on the growth and quality of Brassica rapa L. ssp. chinensis Makino (non-heading Chinese cabbage) under the conditions of no microbial agent application, liquid and solid microbe agents application. The results showed that compared with no microbial agent, application of liquid and solid microbial agent significantly improved soil urease activity, plant nitrogen content, leaf area, SPAD value, and net photosynthetic rate, and increased vegetable production by 26.9% and 34.4% respectively. Meanwhile, the total phenol content and ascorbic acid content of non-heading Chinese cabbage were increased and nitrate content was significantly decreased by applying microbial agents. Thus, rational application of microbial agents promoted the yield and quality of non-heading Chinese cabbage. From the perspective of vegetable growth, liquid microbial agents work fast, solid microbial agents had good long-term efficacy. The cooperating application with organic and inorganic fertilizers would facilitate the excellent quality and high yield of vegetables.

Effects of nutrient fortified complementary food supplements on anemia of infants and young children in poor rural of Gansu.

OBJECTIVE: To assess the effectiveness of complementary food supplements with protein and multi-micronutrients on hemoglobin and anemia in infants and young children. METHODS: In 5 poor counties of Gansu, 984 children aged 6-12 months were enrolled and divided into two groups. In addition to the usual home-made complementary food, all the children were fed one sachet of either Formula I or Formula II supplements each day. Protein and micronutrients were provided in Formula I, while the same energy intake was secured in Formula II as in Formula I. A massive dose of vitamin A was supplemented to all the children every 6 months. Hemoglobin test was done at the same time. RESULTS: Prevalence of anemia was about 35% in both Formula I and Formula II group at baseline, and there were no differences in hemoglobin concentration between the two groups. During the 6-month and 12-month supplementation, hemoglobin of children in Formula I group was higher than that in Formula II group (P < 0.05), and hemoglobin increase in Formula I group was significantly higher than that in Formula II group (P < 0.001). After 6- and 12-month supplementation, the prevalence of anemia in Formula I group dropped to 19.1% and 8.2% respectively, and it was 28.0% and 12.4% in Formula 2 group. The prevalence of anemia in Formula I group was significantly lower than that in Formula II group (P < 0.05). After adjusting age and hemoglobin level at baseline, the hemoglobin increase at age of 24 months in formula 1 group was higher (10.7 g/L vs 7.9 g/L, P < 0.0001). CONCLUSION: Micronutrient fortified complementary food supplements, with large-dose vitamin A, is effective for children aged 6-12 months in terms of iron deficiency prevention.

Effect of operating conditions on the removal of Pb2+ by microporous titanosilicate ETS-10 in a fixed-bed column.

The breakthrough behavior of Pb2+ in an ETS-10 fixed bed was experimentally examined at various operating conditions. Results showed that the adsorption amount of Pb2+ ions per unit mass of ETS-10 particles in a column is about 1.68 mmol/g under the experimental conditions. This amount was not markedly affected by the operating conditions because of the rapid adsorption rate of Pb2+ ions on ETS-10. In the presence of competitive metal ions, the amount of Pb2+ adsorbed on ETS-10 was slightly reduced. An overshoot of the effluent concentrations of competitive metal ions Cu2+ and Cd2+ was observed in the adsorption systems of binary and ternary solutions. This is ascribed to the replacement of pre-adsorbed Cu2+ and Cd2+ ions by Pb2+ ions. The ETS-10 column broken up by Pb2+ ions can be regenerated by using an EDTA-Na2 solution and the regenerated column can be reused.

[Effects of nutrient fortified complementary food supplements on growth of infants and young children in poor rural area in Gansu Province].

OBJECTIVE: To investigate the effects of complementary food supplements with protein and multimicronutrients on growth of infants and yound children in poor rural area in Gansu Province, China. METHODS: In 5 poor counties of Gansu Province, 1478 children aged 4-12 months were enrolled and divided into two groups. In addition to the usual home-made complementary food, all the children were fed one sachet of either formula I or formula II per day, protein and micronutrient were supplemepted in formula I group, fomula II group got energy supplement corresponding with same energy intake as formula I, a massive dose of vitamin A was supplemented to both groups every 6 months interval. Weight and height measurements were done every 3 months until they were 24 months old. RESULTS: At baseline survey, LAZ and WAZ of children in formula II group was better than those of formula I group, the prevalence of under nutrition in formula I was higher than those in formula II group, but not statistically significant. After 12 months supplementation, the differences of LAZ and WAZ between the two groups diminished, the stunting prevalence of the two groups was close, it demonstrated that formula I was slightly more effective than formula II, the effect size was 0.17. Formula I has positive effect independently with the nutrition status of children. When all children were 24 months, formula I was better than formula II in LAZ and WAZ changes P < 0.05), the length changes were bigger in formula I group (P < 0.05). If takeing the children initiating supplementation at under age of 7 month, LAZ changes in formula I group and formula II group was statistically significant (P < 0.005). The average length increased in formula I group was 1.3cm longer. CONCLUSION: Multinutrient-fortified complementary food supplement could be effective for children aged 4-12 month in terms of growth promotion. The study proved that application of home-level fortification of supplementation into the regular complementary feeding in poor rural China may be feasible.

How Sensitive Is the Elasticity of Hydroxyapatite-Nanoparticle-Reinforced Chitosan Composite to Changes in Particle Concentration and Crystallization Temperature?

Hydroxyapatite (HA) nanoparticle-reinforced chitosan composites are biocompatible and biodegradable structural materials that are used as biomaterials in tissue engineering. However, in order for these materials to function effectively as intended, e.g., to provide adequate structural support for repairing damaged tissues, it is necessary to analyse and optimise the material processing parameters that affect the relevant mechanical properties. Here we are concerned with the strength, stiffness and toughness of wet-spun HA-reinforced chitosan fibres. Unlike previous studies which have addressed each of these parameters as singly applied treatments, we have carried out an experiment designed using a two-factor analysis of variance to study the main effects of two key material processing parameters, namely HA concentration and crystallization temperature, and their interactions on the respective mechanical properties of the composite fibres. The analysis reveals that significant interaction occurs between the crystallization temperature and HA concentration. Starting at a low HA concentration level, the magnitude of the respective mechanical properties decreases significantly with increasing HA concentration until a critical HA concentration is reached, at around 0.20-0.30 (HA mass fraction), beyond which the magnitude of the mechanical properties increases significantly with HA concentration. The sensitivity of the mechanical properties to crystallization temperature is masked by the interaction between the two parameters-further analysis reveals that the dependence on crystallization temperature is significant in at least some levels of HA concentration. The magnitude of the mechanical properties of the chitosan composite fibre corresponding to 40 °C is higher than that at 100 °C at low HA concentration; the reverse applies at high HA concentration. In conclusion, the elasticity of the HA nanoparticle-reinforced chitosan composite fibre is sensitive to HA concentration and crystallization temperature, and there exists a critical concentration level whereby the magnitude of the mechanical property is a minimum.

Role of interface in dispersion and surface energetics of polymer nanocomposites containing hydrophilic POSS and layered silicates.

Three different hydrophilic nanofillers--natural and synthetic layered silicate as well as octaammonium polyhedral oligomeric silsesquioxane (POSS)--were incorporated into polyamide-6 by a solution-mixing method. The surfaces of the resulting polymer nanocomposites were characterized by X-ray diffraction, polarized optical microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and contact angle measurements. All polymer nanocomposites displayed enhancement in surface hydrophilicity as well as increase in surface free energy due to surface enrichment of the nanofillers. The degree of enhancement was found to depend on both nanofiller type and dispersion state. Interfacial interactions in the form of hydrogen bonding played an important role in affecting the dispersion state of the layered silicates. Exfoliated layered silicates caused a larger increase in hydrophilicity than aggregated layered silicate. On the other hand, aggregated POSS molecules were able to induce a large increase in hydrophilicity. Significant spreading of water was also observed on surfaces containing POSS molecules. Surface models have been proposed to explain these phenomena.

Surface activated carbon nanospheres for fast adsorption of silver ions from aqueous solutions.

We report the synthesis and activation of colloidal carbon nanospheres (CNS) for adsorption of Ag(I) ions from aqueous solutions. CNS (400-500 nm in diameter) was synthesized via simple hydrothermal treatment of glucose solution. The surface of nonporous CNS after being activated by NaOH was enriched with -OH and -COO(-) functional groups. Despite the low surface area (<15m(2)/g), the activated CNS exhibited a high adsorption capacity of 152 mg silver/g. Under batch conditions, all Ag(I) ions can be completely adsorbed in less than 6 min with the initial Ag(I) concentrations lower than 2 ppm. This can be attributed to the minimum mass transfer resistance as Ag(I) ions were all deposited and reduced as Ag(0) nanoparticles on the external surface of CNS. The kinetic data can be well fitted to the pseudo-second-order kinetics model. The adsorbed silver can be easily recovered by dilute acid solutions and the CNS can be reactivated by the same treatment with NaOH solution. The excellent adsorption performance and reusability have also been demonstrated in a continuous mode. The NaOH activated CNS reported here could represent a new type of low-cost and efficient adsorbent nanomaterials for removal of trace Ag(I) ions for drinking water production.

Covalent immobilization of nisin on multi-walled carbon nanotubes: superior antimicrobial and anti-biofilm properties.

Despite unique and useful properties of multi-walled carbon nanotubes (MWNTs) such as high strength and a low synthesis cost, their weak antimicrobial property hampers their use as an antimicrobial material. Herein, we demonstrate that the immobilization of nisin, a natural and inexpensive antimicrobial peptide, with poly(ethylene glycol) (PEG(1000)) as a linker significantly enhanced the antimicrobial and anti-biofilm properties of MWNTs. The MWNT-nisin composite showed up to 7-fold higher antimicrobial property than pristine MWNTs against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis. Moreover, the MWNT-nisin composite had a dramatically improved capability to prevent biofilm formation both on a deposited film and in suspension. In particular, the MWNT-nisin deposit film exhibited a 100-fold higher anti-biofilm property than the MWNT deposit film. Further, it has been shown that PEG and nisin are covalently attached to MWNTs with excellent stability against leaching. We envision that our novel MWNT-nisin composite can serve as an effective and economical antimicrobial material.