Machine Learning-Assisted Sensor Based on CsPbBr3@ZnO Nanocrystals for Identifying Methanol in Mixed Environments.

Methanol is a respiratory biomarker for pulmonary diseases, including COVID-19, and is a common chemical that may harm people if they are accidentally exposed to it. It is significant to effectively identify methanol in complex environments, yet few sensors can do so. In this work, the strategy of coating perovskites with metal oxides is proposed to synthesize core-shell CsPbBr3@ZnO nanocrystals. The CsPbBr3@ZnO sensor displays a response/recovery time of 3.27/3.11 s to 10 ppm methanol at room temperature, with a detection limit of 1 ppm. Using machine learning algorithms, the sensor can effectively identify methanol from an unknown gas mixture with 94% accuracy. Meanwhile, density functional theory is used to reveal the formation process of the core-shell structure and the target gas identification mechanism. The strong adsorption between CsPbBr3 and the ligand zinc acetylacetonate lays the foundation for the formation of the core-shell structure. The crystal structure, density of states, and band structure were influenced by different gases, which results in different response/recovery behaviors and makes it possible to identify methanol from mixed environments. Furthermore, due to the formation of type II band alignment, the gas response performance of the sensor is further improved under UV light irradiation.

Differential responses of the sunn4 and rdn1-1 super-nodulation mutants of Medicago truncatula to elevated atmospheric CO2.

BACKGROUND AND AIMS: Nitrogen fixation in legumes requires tight control of carbon and nitrogen balance. Thus, legumes control nodule numbers via an autoregulation mechanism. 'Autoregulation of nodulation' mutants super-nodulate are thought to be carbon-limited due to the high carbon-sink strength of excessive nodules. This study aimed to examine the effect of increasing carbon supply on the performance of super-nodulation mutants. METHODS: We compared the responses of Medicago truncatula super-nodulation mutants (sunn-4 and rdn1-1) and wild type to five CO2 levels (300-850 µmol mol-1). Nodule formation and nitrogen fixation were assessed in soil-grown plants at 18 and 42 d after sowing. KEY RESULTS: Shoot and root biomass, nodule number and biomass, nitrogenase activity and fixed nitrogen per plant of all genotypes increased with increasing CO2 concentration and reached a maximum at 700 µmol mol-1. While the sunn-4 mutant showed strong growth retardation compared with wild-type plants, elevated CO2 increased shoot biomass and total nitrogen content of the rdn1-1 mutant up to 2-fold. This was accompanied by a 4-fold increase in nitrogen fixation capacity in the rdn1-1 mutant. CONCLUSIONS: These results suggest that the super-nodulation phenotype per se did not limit growth. The additional nitrogen fixation capacity of the rdn1-1 mutant may enhance the benefit of elevated CO2 for plant growth and N2 fixation.

Elevated CO2 weakens the shift in bacterial community structure in response to 8-year soybean straw return in the same experiment.

A potentially important source for soil organic carbon (SOC) in the agricultural ecosystem is straw, straw return has been shown to affect soil bacterial communities. Facing global climate change, the response of bacterial communities to straw return will change at CO2 enrichment. In this study, we investigate the changes of bacterial communities in response to straw return (+straw) at elevated CO2 (eCO2, 700 ppm) in a long-term field experiment of northeast China. Soil samples were taken in the eighth year and analyzed by high throughput sequencing. Soil bacterial communities exhibited distinct clustering according to straw return and eCO2, while eCO2 shortened the distance of clustering between straw return and not. The relative abundances of 10 genera (Acidobacteria_norank, Candidatus_Solibacter, Gaiella, Nocardioides, Streptomyces, C0119_norank, Roseiflexus, Gemmatimonas, Mizugakiibacter and Rhodanobacter) were significantly affected by the interaction of straw × eCO2. In addition, straw return significantly decreased the relative abundances of Gaiellales_norank, Blastococcus, Psedarthrobacter, and Bacillus and increased that of Geminatimonadaceae_norank, Tepidisphaeraceae, Nitrosomonadaceae_norank, and SC-I-84_norank. These differential responses of genera abundances are illustrative of the susceptibility of bacterial communities and indicate their importance in evaluating the fate of exogenous C. The Clusters of Orthologous Groups (COG) analysis showed that straw return had a greater effect on the relative abundances of COG categories than eCO2. The present results point to the need to focus more strongly on the turnover and storage of straw-C during a chronic straw return in the future.

Greater variation of bacterial community structure in soybean- than maize-grown Mollisol soils in responses to seven-year elevated CO2 and temperature.

Changes in rhizodeposits of crops under elevated CO2 (eCO2) and elevated temperature (eT) may substantially impact on soil microbial community, which in turn affects soil carbon and nutrient cycling. However, the responses of soil bacterial community to long-term eCO2 and eT are not fully understood. A seven-year field experiment using open-top chambers was carried out with soybean (Glycine max L. Merr.) and maize (Zea mays L.) grown in a Mollisol soil under ambient CO2 (380 ppm), eT (2.1 °C increase in air temperature) and eTeCO2 (elevated temperature plus elevated CO2, 2.1 °C increase in air temperature and 700 ppm CO2). Soil DNA was extracted for Illumina MiSeq sequencing. The principal coordinate analysis showed that changes of bacterial community structure due to eT and eTeCO2 were greater in soybean- than maize-grown soils. The eT increased the relative abundances of Gaiella and Bacillus in Actinobacteria and Firmicutes, but decreased those of Nocardioides and H16 in Actinobacteria and Proteobacteria, respectively. The magnitudes of responses of seven genera sensitive to eT varied between soybean- and maize-grown soils. The eTeCO2 decreased the relative abundance of Bacillus and increased those of Gaiella, Streptomyces and Mizugakiibacter. The abundances of Gaiella, Gemmatimonas, and Mizugakiibacter under eTeCO2 were higher in soybean- than maize-grown soils. The redundancy analysis showed that soil organic C, moisture, nitrate, microbial biomass N and Olsen-P significantly affected soil bacterial community composition. All these results indicate that long-term eT increased the abundance of bacterial community and shifted their composition compared to the ambient control. In addition, the bacterial community composition under eTeCO2 was more stable in maize- than soybean-grown soils. The study suggests that warming and crop species may interactively affect the stability of bacterial community linking to the sustainability of soil eco-function in future cropping systems.

Elevated CO2 and temperature increase grain oil concentration but their impacts on grain yield differ between soybean and maize grown in a temperate region.

The increases in CO2 concentration and attendant temperature are likely to impact agricultural production. This study investigated the effects of elevated temperature alone and in combination with CO2 enrichment on grain yield and quality of soybean (Glycine max) and maize (Zea mays) grown in a Mollisol over five-year growing seasons. Plants were grown in open-top chambers with the ambient control, 2.1 °C increase in air temperature (eT) and eT together with 700 ppm atmospheric CO2 concentration (eTeCO2). While eTeCO2 but not eT increased the mean grain yield of soybean by 31%, eTeCO2 and eT increased the yield of maize similarly by around 25% compared to the ambient control. Furthermore, eT and eTeCO2 did not significantly affect grain protein of either species but consistently increased oil concentrations in grains of both species with eTeCO2 increasing more. The eT increased grain Fe concentration relative to the control treatment but decreased Ca concentration, while the relative concentrations of P, K, Mn and Zn varied with crop species. The elevated CO2 enlarged the eT effect on Fe concentration, but decreased the effect on Ca concentration. The results suggest that crop selection is important to maximize yield benefits and to maintain grain quality to cope with elevated CO2 and temperature of future climate change in this temperate region where the temperature is near or below the optimal temperature for crop production.

Improving soil nutrient availability increases carbon rhizodeposition under maize and soybean in Mollisols.

Rhizodeposited carbon (C) is an important source of soil organic C, and plays an important role in the C cycle in the soil-plant-atmosphere continuum. However, interactive effects of plant species and soil nutrient availability on C rhizodeposition remain unclear. This experiment examined the effect of soil nutrient availability on C rhizodeposition of C4 maize and C3 soybean with contrasting photosynthetic capacity. The soils (Mollisols) were collected from three treatments of no fertilizer (Control), inorganic fertilizer only (NPK), and NPK plus organic manure (NPKM) in a 24-year fertilization field trial. The plants were labelled with 13C at the vegetative and reproductive stages. The 13C abundance of shoots, roots and soil were quantified at 0, 7days after 13C labelling, and at maturity. Increasing soil nutrient availability enhanced the C rhizodeposition due to the greater C fixation in shoots and distribution to roots and soil. The higher amount of averaged below-ground C allocated to soil resulted in greater specific rhizodeposited C from soybean than maize. Additional organic amendment further enhanced them. As a result, higher soil nutrient availability increased total soil organic C under both maize and soybean systems though there was no significant difference between the two crop systems. All these suggested that higher soil nutrient availability favors C rhizodeposition. Mean 80, 260 and 300kgfixedCha-1 were estimated to transfer into soil in the Control, NPK and NPKM treatments, respectively, during one growing season.

Frozen cropland soil in northeast China as source of N2O and CO2 emissions.

Agricultural soils are important sources of atmospheric N2O and CO2. However, in boreal agro-ecosystems the contribution of the winter season to annual emissions of these gases has rarely been determined. In this study, soil N2O and CO2 fluxes were measured for 6 years in a corn-soybean-wheat rotation in northeast China to quantify the contribution of wintertime N2O and CO2 fluxes to annual emissions. The treatments were chemical fertilizer (NPK), chemical fertilizer plus composted pig manure (NPKOM), and control (Cont.). Mean soil N2O fluxes among all three treatments in the winter (November-March), when soil temperatures are below -7°C for extended periods, were 0.89-3.01 µg N m(-2) h(-1), and in between the growing season and winter (October and April), when freeze-thaw events occur, 1.73-5.48 µg N m(-2) h(-1). The cumulative N2O emissions were on average 0.27-1.39, 0.03-0.08 and 0.03-0.11 kg N2O_N ha(-1) during the growing season, October and April, and winter, respectively. The average contributions of winter N2O efflux to annual emissions were 6.3-12.1%. In all three seasons, the highest N2O emissions occurred in NPKOM, while NPK and Cont. emissions were similar. Cumulative CO2 emissions were 2.73-4.94, 0.13-0.20 and 0.07-0.11 Mg CO2-C ha(-1) during growing season, October and April, and winter, respectively. The contribution of winter CO2 to total annual emissions was 2.0-2.4%. Our results indicate that in boreal agricultural systems in northeast China, CO2 and N2O emissions continue throughout the winter.

The key role of Shenyan Kangfu tablets, a Chinese patent medicine for diabetic nephropathy: study protocol for a randomized, double-blind and placebo-controlled clinical trial.

BACKGROUND: Diabetic nephropathy (DN) is a major microvascular complication with diabetes. In China, an estimated 34.7 percent of people diagnosed with diabetes have renal complications and a further 50 percent die of renal failure. Hence, identification of alternative treatments for these patients should be given priority. The Shenyan Kangfu tablet (SYKFT) is a new formulation of an existing and widely acclaimed Chinese herbal tea for treating qi-yin deficiency syndrome. Because a considerable portion of DN patients presenting with symptoms of swelling, fatigue and weak limbs would be diagnosed with qi-yin deficiency syndrome according to the traditional Chinese medicine (TCM) diagnostic criteria, we hypothesize that SYKFT may represent a complementary drug for DN patients with the corresponding syndrome. In view of this, we have designed a trial to assess the efficacy and safety of SYKFT for patients with diabetic nephropathy exhibiting signs of qi and yin deficiency. METHODS: This is a multicenter, double-blind, randomized controlled trial (RCT). The total target sample size is planned at 80 participants, with a balanced (1:1) treatment allocation. The experimental intervention will be SYKFY plus irbesartan (SI regimen) and the control intervention will be a placebo plus irbesartan (PI regimen). Participants will receive two courses of medication treatment each lasting 8 weeks. The primary outcome will be the composite of the quantitative 24-hour urinary protein level and urinary albumin excretion rate (UAER). Changes in urine albumin-to-creatinine ratio (UACR) and DN staging, and TCM symptom improvement will be the secondary outcome measures. Adverse events (AEs) will be monitored throughout the trial. DISCUSSION: This study will be the first placebo-controlled RCT to assess whether SYKFT plus irbesartan will have beneficial effects on enhancing overall response rate (ORR), changing DN staging, improving clinical symptoms, and reducing the frequency of AEs for DN patients with qi-yin deficiency syndrome. The results of this trial will help to provide evidence-based recommendations for clinicians.

[Changes of crop yield and soil fertility under long-term fertilization and nutrients-recycling and reutilization on a black soil: IV. Soil organic carbon and its fractions].

A long-term experiment was conducted on a black soil of Northeast China to study the effects of applying chemical fertilizers and recycled organic manure (ROM) on the changes of soil organic carbon and its fractions. The results showed that from 1985 to 2004, soil total organic carbon (TOC) decreased by 7.83% in control,4.56% in N application, 1.61% in N + P application, and 5.56% in ROM application, but increased by 0.33% in N + P + K application. Comparing with single application of ROM, its application with chemical fertilizers, i. e., N + ROM, N + P + ROM, and N + P + K + ROM, increased the TOC concentration by 0.35%, 1.05% and 0.64%, respectively. The readily oxidized carbon (ROC) in fertilization treatments was increased by 8.64% to approximately 28.4%, and the increment was higher in treatments of chemical fertilizers plus ROM than in treatments of chemical fertilizers. The ROC was significantly correlated with soil TOC (Y = 14.192X + 23.9, R2 = 0.802) and stalk yields (Y = 19032X - 7950.6, R2 = 0.759). Light fraction organic carbon (LF-C) had the same trends with ROC. After 20 years fertilization, the organic carbon in soil humic acid and fulvic acid was decreased by 1.64% to approximately 26.23% and 2.33% to approximately 28.68%, respectively, but in treatments of chemical fertilizers plus ROM, the decreasing trend was slowed down.