Hierarchically nanostructured porous hollow microspheres of hydroxyapatite (HAP) are a promising biomaterial, owing to their excellent biocompatibility and porous hollow structure. Traditionally, ...synthetic hydroxyapatite is prepared by using an inorganic phosphorus source. Herein, we report a new strategy for the rapid, sustainable synthesis of HAP hierarchically nanostructured porous hollow microspheres by using creatine phosphate disodium salt as an organic phosphorus source in aqueous solution through a microwave‐assisted hydrothermal method. The as‐obtained products are characterized by powder X‐ray diffraction (XRD), Fourier‐transform IR (FTIR) spectroscopy, SEM, TEM, Brunauer–Emmett–Teller (BET) nitrogen sorptometry, dynamic light scattering (DLS), and thermogravimetric analysis (TGA). SEM and TEM micrographs show that HAP hierarchically nanostructured porous hollow microspheres consist of HAP nanosheets or nanorods as the building blocks and DLS measurements show that the diameters of HAP hollow microspheres are within the range 0.8–1.5 μm. The specific surface area and average pore size of the HAP porous hollow microspheres are 87.3 m2g−1 and 20.6 nm, respectively. The important role of creatine phosphate disodium salt and the influence of the experimental conditions on the products were systematically investigated. This method is facile, rapid, surfactant‐free and environmentally friendly. The as‐prepared HAP porous hollow microspheres show a relatively high drug‐loading capacity and protein‐adsorption ability, as well as sustained drug and protein release, by using ibuprofen as a model drug and hemoglobin (Hb) as a model protein, respectively. These experiments indicate that the as‐prepared HAP porous hollow microspheres are promising for applications in biomedical fields, such as drug delivery and protein adsorption.
Sleepy hollow: Hydroxyapatite (HAP) microspheres were synthesized from creatine phosphate as a biocompatible phosphorus source (see figure). As‐prepared nanostructured porous hollow microspheres show relatively high drug‐loading and high protein‐adsorption capacity.
Different fertilization regimes can substantially influence soil fungal community composition, yet fewer studies try to control for the effects of nitrogen input. Here, we investigated the impact of ...fertilization with equal nitrogen upon soil properties and soil fungal diversity and community composition in the North China Plain in a long-term field experiment. Long-term (32 years) fertilization regimes were applied with equal amounts of nitrogen: no chemical fertilizer or organic manure; chemical fertilization only; organic manure fertilization only, and; combination of 1/2 chemical fertilizer and 1/2 organic manure. Then we investigated the influence of these four fertilization regimes to soil properties, fungal diversity and community composition. The results showed that applying organic manure significantly influenced soil properties. Illumina MiSeq sequencing and its analysis revealed that organic manure fertilization significantly changed soil fungal alpha diversity, but chemical fertilization did not. Although soil fungal community composition did not differ significantly among all the fertilization regimes at the phylum and class levels, they did show differences in the abundance of dominant fungi. Yet at the genus level, soil fungal community composition, abundance, and beta diversity was affected by all fertilization regimes. Application of organic manure also reduced the abundance of soil-born fungal pathogens such as Fusarium. Our results suggest that long-term application of organic manure could markedly improve soil properties, altering soil fungal community composition and its diversity. Moreover, organic manure fertilization could limit soil-born fungal diseases, to further contribute to soil ecosystem sustainability.
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•Chitosan-coated mesoporous microspheres of calcium silicate hydrate are prepared.•A simple, low-cost and environmentally friendly solution method is reported.•The product is a highly ...efficient adsorbent for heavy metal ions.
Chitosan-coated calcium silicate hydrate (CSH/chitosan) mesoporous microspheres formed by self-assembly of nanosheets have been synthesized in aqueous solution under ambient conditions without using any toxic surfactant or organic solvent. The method reported herein has advantages of simplicity, low cost and being environmentally friendly. The BET specific surface area of CSH/chitosan mesoporous microspheres is measured to be as high as ∼356m2g–1, which is considerably high among calcium silicate materials. The as-prepared CSH/chitosan mesoporous microspheres are promising adsorbent and exhibit a quick and highly efficient adsorption behavior toward heavy metal ions of Ni2+, Zn2+, Cr3+, Pb2+ Cu2+ and Cd2+ in aqueous solution. The adsorption kinetics can be well fitted by the pseudo second-order model. The maximum adsorption amounts of Ni2+, Zn2+, Pb2+, Cu2+ and Cd2+ on CSH/chitosan mesoporous microspheres are extremely high, which are 406.6, 400, 796, 425 and 578mg/g, respectively. The CSH/chitosan adsorbent exhibits the highest affinity for Pb2+ ions among five heavy metal ions. The adsorption capacities of the CSH/chitosan adsorbent toward heavy metal ions are relatively high compared with those reported in the literature.
As one of the staple food crops, rice（Oryza sativa L.） is widely cultivated across China, which plays a critical role in guaranteeing national food security. Most previous studies on grain yield ...or/and nitrogen use efficiency（NUE） of rice in China often involved site-specific field experiments, or small regions with insufficient data, which limited the representation for the current rice production regions. In this study, a database covering a wide range of climate conditions, soil types and field managements across China, was developed to estimate rice grain yield and NUE in various rice production regions in China and to evaluate the relationships between N rates and grain yield, NUE. According to the database for rice, the values of grain yield, plant N accumulation, N harvest index（HIN）, indigenous N supply（INS）, internal N efficiency（IE_N）, reciprocal internal N efficiency（RIE_N）, agronomic N use efficiency（AE_N）, partial N factor productivity（PEPN）, physiological N efficiency（PE_N）, and recover efficiency of applied N（RE_N） averaged 7.69 t ha~（–1）, 152 kg ha~（–1）, 0.64 kg kg~（–1）, 94.1 kg kg~（–1）, 53.9 kg kg~（–1）, 1.98 kg kg~（–1）, 12.6 kg kg~（–1）, 48.6 kg kg~（–1）, 33.8 kg kg~（–1）, and 39.3%, respectively. However, the corresponding values all varied tremendously with large variation. Rice planting regions and N rates had significant influence on grain yield, N uptake and NUE values. Considering all observations, N rates of 200 to 250 kg ha~（–1） commonly achieved higher rice grain yield compared to less than 200 kg N ha~（–1） and more than 250 kg N ha~（–1） at most rice planting regions. At N rates of 200 to 250 kg ha~（–1）, significant positive linear relationships were observed between rice grain yield and AE_N, PE_N, RE_N, IE_N, and PFPN, and 46.49, 24.64, 7.94, 17.84, and 88.24% of the variation in AE_N, PE_N, RE_N, IE_N, and PFPN could be explained by grain yield, respectively. In conclusion, in a reasonable range of N application, an increase in grain yield can be achieved accompanying by an acceptable NUE.
Exploration of soil environmental characteristics governing soil microbial community structure and activity may improve our understanding of biogeochemical processes and soil quality. The impact of ...soil environmental characteristics especially organic carbon availability after 15-yr different organic and inorganic fertilizer inputs on soil bacterial community structure and functional metabolic diversity of soil microbial communities were evaluated in a 15-yr fertilizer experiment in Changping County, Beijing, China. The experiment was a wheat-maize rotation system which was established in 1991 including four different fertilizer treatments. These treatments included： a non-amended control（CK）, a commonly used application rate of inorganic fertilizer treatment（NPK）; a commonly used application rate of inorganic fertilizer with swine manure incorporated treatment（NPKM）, and a commonly used application rate of inorganic fertilizer with maize straw incorporated treatment（NPKS）. Denaturing gradient gel electrophoresis（DGGE） of the 16 S r RNA gene was used to determine the bacterial community structure and single carbon source utilization profiles were determined to characterize the microbial community functional metabolic diversity of different fertilizer treatments using Biolog Eco plates. The results indicated that long-term fertilized treatments significantly increased soil bacterial community structure compared to CK. The use of inorganic fertilizer with organic amendments incorporated for long term（NPKM, NPKS） significantly promoted soil bacterial structure than the application of inorganic fertilizer only（NPK）, and NPKM treatment was the most important driver for increases in the soil microbial community richness（S） and structural diversity（H）. Overall utilization of carbon sources by soil microbial communities（average well color development, AWCD） and microbial substrate utilization diversity and evenness indices（H＇ and E） indicated that long-term inorganic fertilizer with organic amendments incorporated（NPKM, NPKS） could significantly stimulate soil microbial metabolic activity and functional diversity relative to CK, while no differences of them were found between NPKS and NPK treatments. Principal component analysis（PCA） based on carbon source utilization profiles also showed significant separation of soil microbial community under long-term fertilization regimes and NPKM treatment was significantly separated from the other three treatments primarily according to the higher microbial utilization of carbohydrates, carboxylic acids, polymers, phenolic compounds, and amino acid, while higher utilization of amines/amides differed soil microbial community in NPKS treatment from those in the other three treatments. Redundancy analysis（RDA） indicated that soil organic carbon（SOC） availability, especially soil microbial biomass carbon（Cmic） and Cmic/SOC ratio are the key factors of soil environmental characteristics contributing to the increase of both soil microbial community structure and functional metabolic diversity in the long-term fertilization trial. Our results showed that long-term inorganic fertilizer and swine manure application could significantly improve soil bacterial community structure and soil microbial metabolic activity through the increases in SOC availability, which could provide insights into the sustainable management of China＇s soil resource.
Highly stable amorphous calcium phosphate (ACP) porous nanospheres with a relatively uniform size and an average pore diameter of about 10 nm have been synthesized by using a microwave‐assisted ...hydrothermal method with adenosine 5′‐triphosphate disodium salt (ATP) as the phosphorus source and stabilizer. The as‐prepared ACP porous nanospheres have a high stability in the phosphate buffer saline (PBS) solution for more than 150 h without phase transformation to hydroxyapatite, and the morphology and size were essentially not changed. The important role of ATP and effects of experimental conditions on the formation of ACP porous nanospheres were also investigated. The ACP porous nanospheres were characterized by X‐ray powder diffraction (XRD), Fourier‐transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). This method is facile, rapid, surfactant‐free and environmentally friendly. The as‐prepared ACP porous nanospheres are efficient for anticancer drug (docetaxel) loading and release. The ACP porous nanosphere drug‐delivery system with docetaxel shows a high ability to damage tumor cells, thus, is promising for the application in anticancer treatment.
Stabilized nanospheres: Highly stable amorphous calcium phosphate (ACP) porous nanospheres with an average pore diameter of about 10 nm have been synthesized by using a microwave‐assisted hydrothermal method with adenosine 5′‐triphosphate disodium salt (ATP) as the phosphorus source and stabilizer (see scheme). The as‐prepared ACP porous nanospheres show a high ability to damage tumor cells after loading docetaxel, thus, are promising for application in anticancer drug delivery.
Humic acid (HA) is a readily available and low-cost material that is used to enhance crop production and reduce nitrogen (N) loss.However,there is little consensus on the efficacy of different HA ...components.In the current study,a soil column experiment was conducted using the 15N tracer technique in Dezhou City,Shandong Province,China,to compare the effects of urea with and without the addition of weathered coal-derived HA components on maize yield and the fate of fertilizerderived N (fertilizer N).The HA components were incorporated into urea by blending different HA components into molten urea to obtain the three different types of HA-enhanced urea (HAU).At harvest,the aboveground dry biomass of plants grown with HAU was enhanced by 11.50-21.33％ when compared to that of plants grown with U.More significantly,the grain yields under the HAU treatments were 5.58-18.67％ higher than the yield under the urea treatment.These higher yields were due to an increase in the number of kernels per plant rather than the weight of individual kernels.The uptake of fertilizer N under the HAU treatments was also higher than that under the urea treatment by 11.49-29.46％,while the unaccounted N loss decreased by 12.37-30.05％.More fertilizer-derived N was retained in the 0-30 cm soil layer under the HAU treatments than that under the urea treatment,while less N was retained in the 30-90 cm soil layer.The total residual amount of fertilizer N in the soil column,however,did not differ significantly between the treatments.Of the three HAU treatments investigated,the one with an HA fraction derived from extraction with pH values ranging from 6 to 7,resulted in the best improvement in all assessment targets.This is likely due to the abundance of the COO/C-N=O group in this HA component.
Calcium carbonate is a common substance found in rocks worldwide, and is the main biomineral formed in shells of marine organisms and snails, pearls and eggshells. Amorphous calcium carbonate (ACC) ...is the least stable polymorph of calcium carbonate, which is so unstable under normal conditions that it is difficult to be prepared in vitro because it rapidly crystallizes to form one of the more stable polymorphs in aqueous solution. Herein, we report the successful synthesis of highly stable ACC nanospheres in vitro using adenosine 5′‐triphosphate disodium salt (ATP) as a stabilizer. The effect of ATP on the stability of ACC nanospheres is investigated. Our experiments show that ATP plays an unique role in the stabilization of ACC nanospheres in aqueous solution. Moreover, the as‐prepared ACC nanospheres are highly stable in phosphate buffered saline for a relatively long period of time (12 days) even under relatively high concentrations of calcium and phosphate ions. The cytotoxicity tests show that the as‐prepared highly stable ACC nanospheres have excellent biocompatibility. The highly stable ACC nanospheres have high protein adsorption capacity, implying that they are promising for applications in biomedical fields such as drug delivery and protein adsorption.
Highly stable amorphous calcium carbonate (ACC) nanospheres are prepared using ATP biomolecule as the stabilizer in aqueous solution. The as‐prepared ACC nanospheres have high protein adsorption capacity and pH responsive protein release property, thus are promising for applications in biomedical fields such as drug delivery and protein adsorption.
The aim of drip fertigation is synchronising the application of water and nutrients with crop requirements, and maintaining the proper concentration and distribution of nutrient and water in the ...soil. The wetting patterns and nutrient distributions under drip fertigation have been proved to be closely related to the fertigation strategies. In order to find out the critical factors that affect the nutrient distribution under different drip fertigaiton strategies, a computer simulation model HYDRUS2D/3D was used to simulate the water and nitrate distribution for various fertigation strategies from a surface point source. Simulation results were compared with the observed ones from our previous studies. A 15° wedge-shaped plexiglass container was used in our experiment to represent one-twenty-fourth of the complete cylinder. The height of container is 40 cm, and the radius is 41 cm. The ammonium nitrate solution was added through a no. 7 needle connected to a Mariotte tube with a flexible hose. The soil water content, nitrate and ammonium concentrations were measured. The comparison of simulated and observed data demonstrated that the model performed reliably. The numerical analysis for various fertigation strategies from a surface point source showed that：（1） The total amount of irrigation water, the concentration of the fertilizer solution and the amount of pure water used to flush the pipeline after fertilizer solution application are the three critical factors influencing the distribution of water and fertilizer nitrogen in the soil.（2） The fresh water irrigation duration prior to fertigation has no obvious effect on nitrate distribution. The longer flushing time period after fertigation resulted in nitrate accumulation closer to the wetting front. From the point of avoiding the possibility of nitrate loss from the root zone, we recommended that the flushing time period should be as shorter as possible.（3） For a given amount of fertilizer, higher concentration of the fertilizer applied solution reduces the potential of nitrate leaching in drip irrigation system. While, lower concentration of the fertilizer solution resulted in an uniform distribution of nitrate band closer to the wetted front.
Plant endophytes exhibit an excellent ability to promote plant growth and control plant diseases. However, the influence of long‐term fertilisation regimes on the diversity and community of plant ...endophytes has seldom been reported. In this research, Illumina MiSeq sequencing was used to investigate the effect of 34 years of different fertilisation regimes on the diversity and community of wheat (Triticum aestivum L.) leaf endophytes. Results showed that different fertilisation regimes could significantly influence the diversity and community of wheat leaf endophytes. The diversity of leaf endophytes after organic manure fertilisation was different from the diversity after chemical fertilisation and no fertilisation. The endophyte community was significantly different under different fertilisation regimes. Pseudomonas has higher abundance after chemical and organic manure fertilisation than in the no fertilisation treatment. The abundance of Brevundimonas in the organic manure fertilisation treatment group is higher than in chemical and no fertilisation treatment. Redundancy analysis (RDA) showed that the endophyte communities in the chemical and organic manure fertilisation were positively correlated with wheat height, stem diameter, leaf area and yield. This research lays the foundations for understanding the diversity and community of wheat leaf endophytes under different fertilisation regimes and provides useful information for further scientific research on fertilisation.
Different fertilisation regimes could significantly influence the diversity and community of wheat leaf endophytes. The diversity of leaf endophytes after organic manure fertilisation was different from the diversity after chemical fertilisation and no fertilisation.
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