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Many UAVs today have an S-bend inlet for the sake of stealth; however, the majority of them have a relatively gentle transition of the flow channel. This study presents an experimental investigation of the aerodynamic performance and swirl flow characteristics of a UAV inlet with double 90° bends, which is also integrated with an aircraft fuselage as well as a volute. The influences of angle of attack, sideslip angle, AIP Mach number and freestream speed are explored in detail. The influences of the deflectors installed ahead of the first 90° bend of the inlet and the baffle installed at the bottom of the volute are revealed. It is found that both the deflectors and the baffle are beneficial in enhancing the aerodynamic performance of the inlet and alleviating the intensity of the swirl flow inside the volute. [ABSTRACT FROM AUTHOR]

The addition of fertilizers is indispensable in agricultural production, and currently, there is a wide variety of new types of fertilizers available. For example, commonly used are stabilized fertilizers with inhibitors and coated slow-release fertilizers, among others. However, the long-term effects of these fertilizers, when applied continuously are still uncertain. This study will provide scientific and theoretical support for the development and promotion of these fertilizers. A 16-year paddy field with brown soil treated with different urease and nitrification inhibitors, sulfur-coated urea (SCU), and resin-coated urea (PCU) was studied. The study showed that long-term use of conventional urea nitrogen fertilizer resulted in a significant reduction in soil total phosphorus (TP). Long-term application of NBPT and conventional urea significantly increased soil organic matter (SOM). Moreover, except for HQ and NBPT+DMPP, the prolonged application of new urea fertilizers also significantly enhanced soil total potassium (TK). Application of SCU fertilizer in brown soil type paddy fields resulted in a significant decrease in soil pH over time. However, changes in pH had no effect on the abundance of ammonia-oxidizing bacteria (AOB), as AOB was mainly affected by soil-available N. DMPP, HQ+DCD, NBPT+DMPP, SCU, and PCU significantly reduced the 16S rRNA gene copy number of soil bacteria, with the greatest effect of coated urea fertilizer (SCU and PCU). Long-term application of stable urea fertilizer with HQ significantly reduced the bacterial community in paddy soil. Conversely, HQ+DCD-stabilizede urea fertilizer significantly increased the population structure and abundance of Basidiomycota fungi while decreasing the population structure and abundance of Rozellomycota fungi. DMPP-stabilized urea fertilizer notably increased the population structure and abundance of Ascomycota fungi while decreasing the population structure and abundance of Rozellomycota and Chytridiomycota fungi. Furthermore, HQ-stabilized urea fertilizer significantly reduced the population structure and abundance of Chytridiomycota fungi. [ABSTRACT FROM AUTHOR]

Japanese farms currently occur on a small but expanding average physical scale and annual sales, in a decreasing and aging labor force, increasingly abandoned farmland and massive access of corporations powerful in capital and management. The government has proposed to accelerate agricultural growth through adopting high‐level smart technologies in large‐scale farms, with a series of favorite policies and measures. This paper reviews the connotations, characteristics and technologies of smart agriculture in the views of Japanese scholars, the practice of smart agriculture in Japan, followed by a case study on the smart rice production model 'NoshoNavi1000'. The results show that Japanese scholars have conducted in‐depth and massive studies in smart agriculture, with regional characteristics in the orientations on labor‐saving, precise management, disaster reduction and inheriting traditional farming skills. The government's ambitious objective is supported by its all‐round policy package, including project demonstration, supporting services, environmental improvement, education and training, and overseas outreaching. Closely combined with the planting structure of Japanese agriculture, rice production is an important sector for the R&D and application of smart farming in the form of either individual technologies or models. The policies and technologies have achieved benefits in saving labor and production costs, and improving the profit margin. Through years of on‐farm application, 'NoshoNavi1000' has been developed to involve the major technological components of smart agriculture. It has contributed to improving rice yield, production efficiency and profitability of large‐scale farms, through real‐time data collection, comprehensive and professional data mining, and specific and practical feedbacks. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In order to improve the application effect of inhibitors, the combination of seaweed extracts (SE), urease inhibitors (UIs) and nitrification inhibitors (NIs) were added to urea fertilizers for providing a theoretical basis to develop the efficient stabilized nitrogen (N) fertilizer. The combinations were tested in outdoor pots with no N fertilizer (CK) and application of urea alone (U) as control, and SE, N-butyl phosphorothioate triamine (NBPT), 3,4-dimethylpyrazole phosphate (DMPP), 2-chloro-6-trimethylpyridine (CP), and combinations of SE with each of the three inhibitors were added to urea to make seven fertilizer prototypes. The results showed that the addition of inhibitors and SE could regulate the N transformation, enzyme activity and microbial biomass carbon (MBC) contents and significantly improve maize yield and N use efficiency (NUE) (p < 0.05). Compared with the addition of inhibitor alone, the addition of SE was beneficial to N uptake by plants at the early growth stage of maize, but reduced the inhibitors effect; DMPP + S significantly increased the maize total biomass and NUE (p < 0.05), and the grain yield, N uptake and NUE by 15.6%, 28.5% and 30.6%, respectively. Therefore, the addition of DMPP with SE to urea significantly improved yield when planting maize in loess areas. [ABSTRACT FROM AUTHOR]

Application of nitrification inhibitors (NIs) with nitrogen (N) fertilizer is one of the most efficient ways to improve nitrogen use efficiency (NUE). To fully understand the efficiency of NIs with N fertilizer on soil nitrification, yield and NUE of maize (Zea mays L.), an outdoor pot experiment with different NIs in three soils with different pH was conducted. Five treatments were established: no fertilizer (Control); ammonium sulfate (AS); ammonium sulfate + 3, 4-dimethyl-pyrazolate phosphate (DMPP) (AD); ammonium sulfate + nitrogen protectant (N-GD) (AN); ammonium sulfate + 3, 4-dimethyl-pyrazolate phosphate + nitrogen protectant (ADN). The results showed that NIs treatments (AD, AN and ADN) significantly reduced soil nitrification in the brown and red soil, especially in AD and ADN, which decreased apparent nitrification rate by 28% - 44% (P < 0.05). All NIs treatments significantly increased yield and NUE of maize in three soils, especially ADN in the cinnamon soil and AD in the red soil were more efficiency, which significantly increased maize yield and apparent nitrogen recovery by 5.07 and 6.81 times, 4.39 and 8.16 times, respectively. No significant difference on maize yield was found in the brown soil, but AN significantly increased apparent nitrogen recovery by 70%. Given that the effect of NIs on both soil nitrification and NUE of maize, DMPP+N-GD was more efficient in the cinnamon soil, while N-GD and DMPP was the most efficiency in the brown and red soil, respectively. In addition, soil pH and soil organic matter play important role in the efficiency of NIs. [ABSTRACT FROM AUTHOR]

Nitrification inhibitors (NIs) affect nitrogen (N) cycle and crop yield, but how the combinations of NIs influence N transformation and maize yield remains unclear. An outdoor pot experiment was performed to explore the effect of three NIs (nitrapyrin (CP), 3, 4-dimethylpyrazole phosphate (DMPP) and dicyandiamide (DCD)) and their combinations on mineral N transformation, yield and N use efficiency (NUE) of maize in a brown soil and a cinnamon soil from northeast China. Higher yield and NUE were obtained in the brown soil than that in the cinnamon soil. All treatments with NIs significantly increased NH4+-N content, grain yield and NUE in both soils, especially for NIs combination (DMPP + DCD in the brown soil and CP + DCD in the cinnamon soil). These two treatments significantly increased yield and apparent nitrogen recovery by 1.84 and 2.31 times, 10.24 and 6.39 times, respectively, compared with N fertilizer treatment. They also showed lower apparent nitrification rates (17.2% and 53.7%, respectively) compared with single NIs treatments. Considering both the inorganic N supply and agronomic effect of NIs, DMPP + DCD and CP + DCD are the best strategies for the application of NIs in the brown soil and cinnamon soil. [ABSTRACT FROM AUTHOR]

Amino acids are important components of the soil organic nitrogen pool. There is, however, a current lack of knowledge concerning how exogenous C and N regulate amino acid uptake in the soil microorganism/plant system. We used a 13C,15N-glycine injection method to examine glycine-derived 13C and 15N partitioning in a planted or unplanted spring wheat pot experiment. Four treatments were used: control (CK), ammonium sulfate (N), glucose (C), and ammonium sulfate with glucose (NC). The results showed that amino acids were absorbed intact by soil microorganisms and plants at 4 h. An exogenous excess of C, rather than N, resulted in a reduced uptake of intact glycine by soil microorganisms, indicating that glycine was taken up primarily to fulfill their C requirement. Wheat was more effective in competing for glycine-C and N at 24 h. 13C and 15N partitioning in wheat was significantly influenced by exogenous C and N availability; uptake of 13C and 15N by wheat increased with increasing C and N availability. We concluded that amino acids are important not only for N but also for C to soil microorganisms and plants, which are able to respond quickly to exogenous C and N source application. [ABSTRACT FROM AUTHOR]

Sanjie Zhentong capsule, a well-known traditional Chinese medicine prescription, are used for the treatment of endometriosis-related diseases. In this study, a simple, rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) method was developed for the simultaneous determination of ten bioactive constituents, including peimine, peiminine, peimisine, loureirin A, loureirin B, 7,4′-dihydroxyflavone, pterostilbene, ginsenoside Rg1, ginsenoside Rb1, and notoginsenoside R1 in rat plasma after oral administration of Sanjie Zhentong capsule. The sample preparations for protein removal was accomplished using a simple methanol precipitation method. The analytes were completely separated from the endogenous compounds on an Agilent Poroshell 120 SB-C18 column (4.6 mm × 150 mm, 2.7 μm) using an isocratic elution with methanol − 0.1% formic acid aqueous (4/1, v/v) as a mobile phase. The single-run analysis time was as short as 14.0 min. The inter-day and intra-day precision of the quality control samples exhibited relative standard deviations (RSD) <9.5% and the accuracy values ranged from −8.6% to 15.0%. The lower limits of quantification (LLOQ) were 10, 10, 10, 10, 10, 10, 5, 10, 10 and 20 ng/mL for peimine, peiminine, peimisine, loureirin A, loureirin B, 7,4′-dihydroxyflavone, pterostilbene, ginsenoside Rg1, ginsenoside Rb1, notoginsenoside R1, respectively. The analytical method was successfully applied to a pharmacokinetic study of the multi-components after oral administration of Sanjie Zhentong Capsule in rats. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop an analytical method for the simultaneous determination of ultra-trace levels of 35 organophosphorus pesticide residues in Sanjie Zhentong capsules, a traditional Chinese medicine prescription. A method based on multiclass and multiresidue sample preparation was developed. First, samples were hydrated with water at 4°C. A ratio of 1:3 sample/water was used for each of the sample amounts. Then, different extraction solvents were screened. This step was followed by a dispersive solid-phase extraction clean-up procedure using both primary secondary amine and polyamide. A comprehensive sensitive multiresidue liquid chromatography tandem mass spectrometry method was investigated and validated. Good linearity was achieved in the range of 10-500 μg/kg for each analyte. The average recovery ranged from 70 to 120%, except for methamidophos, fonophos, diazinon, and chlorpyriphos-ethyl, the recoveries of which ranged from 60-70% at the lower concentration level. The precision values were lower than 10% for all the compounds in three concentration levels. The limits of detection and limits of quantification values were 0.01-2.1 and 0.05-3.4 μg/kg, respectively. The matrix effects were determined, and most of the compounds showed signal suppression. Finally, this optimized procedure was applied for the analysis of real samples. [ABSTRACT FROM AUTHOR]

This study investigated the influence of nitrogen (N) fertilizer and straw on intact amino acid N uptake by soil microorganisms and the relationship between amino acid turnover and soil properties during the wheat growing season. A wheat pot experiment was carried out with three treatments: control (CK), N fertilizer (NF) and N fertilizer plus rice straw (NS). We used stable isotope compound-specific analysis to determine the uptake of 13C,15N-glycine by soil microorganisms. In the NF treatment, microbial 13C,15N-glycine uptake was lower compared with CK, suggesting that inorganic N was the preferred N source for soil microorganisms. However, The application of straw with N fertilizer (in NS treatment) increased microbial 13C,15N-glycine uptake even with the same amount of N fertilizer application. In this treatment, enzyme activities, soil microbial biomass C and microbial biomass N increased simultaneously because more C was available. Soil mineral N and plant N contents all decreased substantially. The increased uptake of intact 13C,15N-glycine in the NS treatment can be attributed to direct assimilation by soil microorganisms to satisfy the demand for N when inorganic N was consumed. [ABSTRACT FROM AUTHOR]

Cytarabine has a poor oral absorption due to its rapid deamination and poor membrane permeability. Bile acid transporters are highly expressed both in enterocytes and hepatocytes and to increase the oral bioavailability and investigate the potential application of cytarabine for liver cancers, a transporter- recognizing prodrug strategy was applied to design and synthesize four conjugates of cytarabine with cholic acid (CA), chenodeoxycholic acid (CDCA), hyodeoxycholic acid (HDCA) and ursodeoxycholic acid (UDCA). The anticancer activities against HepG2 cells were evaluated by MTT assay and the role of bile acid transporters during cellular transport was investigated in a competitive inhibition experiment. The in vitro and in vivo metabolic stabilities of these conjugates were studied in rat plasma and liver homogenates. Finally, an oral bioavailability study was conducted in rats. All the cholic acid-cytarabine conjugates (40 μM) showed potent antiproliferative activities (up to 70%) against HepG2 cells after incubation for 48 h. The addition of bile acids could markedly reduce the antitumor activities of these conjugates. The N 4 -ursodeoxycholic acid conjugate of cytarabine (compound 5 ) exhibited optimal stability ( t 1/2 = 90 min) in vitro and a 3.9-fold prolonged half-life of cytarabine in vivo . More importantly, compound 5 increased the oral bioavailability 2-fold compared with cytarabine. The results of the present study suggest that the prodrug strategy based on the bile acid transporters is suitable for improving the oral absorption and the clinical application of cytarabine. [ABSTRACT FROM AUTHOR]

The study of pharmacokinetics of Ginkgo biloba extracts in Traditional Chinese Medicine was relatively recent. In this study, a simple, quick and sensitive LC-MS/MS analytical method was developed for the determination of ginkgolides A, B, C and bilobalide in rat plasma. The analytes were completely separated from the endogenous compounds on an Agilent Zorbax Eclipse plus C18 column (50 mm × 3.0 mm, 1.8 µm) using an isocratic elution. The single-run analysis time was as short as 5.0 min. Sample preparation for protein removal was accomplished used a simple methanol precipitation method, after SPE showing a simultaneous extraction and cleanup of extracts allowing for a direct analysis. Extraction recoveries in rat plasma for ginkgolides A, B, C and bilobalide ranged from 75.6% to 89.0%. The calibration curves were determined over the ranges 0.5-20,000 ng/mL for ginkgolides A, B, C and bilobalide respectively. The lower limits of quantification (LLOQ) of the analytes were 0.5 ng/mL. Inter-day and intra-day precision and accuracy were below 15% and between 85 and 115%, respectively. Finally, the developed method was successfully applied to a pharmacokinetic study following oral administration of the Ginkgo biloba extracts to the male ICR rats. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The application of nitrification inhibitors (NIs) based on ammonium (NH4+) is considered to be an efficient way to reduce nitrogen (N) loss by delaying the nitrification process through influencing ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). However, the inhibition mechanisms of NIs on AOA and AOB in different soils remain unclear. Hence, we explored the two commonly used NIs (3, 4-dimethylepyrazole phosphate (DMPP) and dicyandiamide (DCD) and their combination (DMPP + DCD) on the soil nitrification and abundance of ammonia oxidizers (AOA and AOB) in three black soils (HLJ, NA, and DA) with different physicochemical properties using a 120-day incubation experiment. The results demonstrated that NIs significantly increased NH4+-N concentrations and decreased NO3−-N concentrations in all three tested soils. There was no significant difference in inhibiting nitrification in HLJ among all NI treatments, while DCD was more efficient in NA, DMPP + DCD had better efficiency in DA. The potential nitrification rate (PNR) was greatly decreased by NIs addition, and PNR was significantly positively correlated with AOB (p < 0.05). AOA was dominant in the acid soil. All NI treatments significantly inhibited soil nitrification through inhibiting the growth of AOB in the two soils with higher pH. The abundance of AOA and AOB was significantly correlated with different soil types (positively correlated with soil pH, and negatively correlated with organic matter). Moreover, soil pH and soil organic matter were considered to be the most important factors influencing the inhibition efficiency of NIs and the abundance of AOA and AOB. The application of the NIs combination (DMPP + DCD) was considered to be the most cost-effective way to inhibit soil nitrification in soil with higher pH and lower SOM, which provides a theoretical basis for a field experiment. [ABSTRACT FROM AUTHOR]

External organic nitrogen (N) inputs can contrastingly affect the transformation and availability of N in forest soils, which is an important potential N resource and is possibly vulnerable to soil properties. Little is known about the transformation and availability of external small molecule organic N in forest soils and the underlying microbial mechanisms. Soil samples from Changbai Mountain at different altitudes (from 750 m to 2200 m) that ranged widely in soil properties were incubated with 13C, 15N-labeled glycine. The fate of 15N-glycine and the incorporation of 13C into different phospholipid fatty acids (PLFAs) were measured at the same time. The addition of glycine promoted gross N mineralization and microbial N immobilization significantly. Mineralization of glycine N accounted for 6.2–22.5% of the added glycine and can be explicable in the light of a readily mineralizable substrate by soil microorganisms. Assimilation of glycine N into microbial biomass by the mineralization-immobilization-turnover (MIT) route accounted for 24.7–52.1% of the added label and was most mightily affected by the soil C/N ratio. We also found that the direct utilization of glycine is important to fulfill microorganism growth under the lack of available carbon (C) at upper elevations. The labeled glycine was rapidly incorporated into the PLFAs and was primarily assimilated by bacteria, indicating that different groups of the microbial community were answerable to external organic N. G+ bacteria were the main competitors for the exogenous glycine. Increased intact incorporation of glycine into microbial biomass and the concentration of PLFAs in general, particularly in G+ bacteria, suggest a diversified arrangement to response changes in substrate availability. [ABSTRACT FROM AUTHOR]

The application of nitrification inhibitors (NIs) is considered to be an efficient way to delay nitrification, but the effect of NIs combinations on soil nitrification and ammonia (NH3) volatilization are not clear in soils with different pH values. In this study, we explored the effect of nitrapyrin (CP) and its combinations with 3, 4-dimethylepyrazole phosphate (DMPP), dicyandiamide (DCD) on the transformation of nitrogen, potential nitrification rate (PNR), and ammonia (NH3) volatilization in a 120-day incubation experiment with three different pH values of black soil. Treatments included no fertilizer (Control), ammonium sulfate (AS), AS+CP (CP), AS+CP+DMPP (CP+DMPP), and AS+CP+DCD (CP+DCD). The application of NIs significantly decreased NO3−-N contents and potential nitrification rate (p < 0.05), while significantly increased NH4+-N contents (p < 0.05), especially CP+DCD and CP+DMPP were the most effective in the neutral and alkaline soils, respectively. In the acid soil, CP significantly increased total NH3 volatilization by 31%, while CP+DCD significantly reduced by 28% compared with AS. However, no significant difference was found in NH3 volatilization with and without NIs treatments (p > 0.05) in the neutral and alkaline soils. In conclusion, the combined nitrification inhibitors had the better efficiency in all three tested soils. CP+DCD and CP+DMPP are the most effective in inhibiting soil nitrification in the clay soils with higher pH value and lower organic matter, while CP+DCD had the potential in mitigating environment pollution by reducing N loss of NH3 volatilization in the loam soil with lower pH value and higher organic matter. It provided a theoretical basis for the application of high efficiency fertilizer in different soils. Further studies under field conditions are required to assess the effects of these nitrification inhibitors. [ABSTRACT FROM AUTHOR]

Abstract: A simple and sensitive HPLC–MS/MS method was developed and validated for the simultaneous determination of decitabine and valdecitabine in rat plasma. The analytes were separated on a C18 column (150mm×4.6mm, 3.5μm) and a triple-quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source was applied for detection. A clean solid-phase extraction procedure with cation exchange cartridge was employed to extract the analytes from rat plasma with high recovery of decitabine (>82%). The calibration curves were linear over a concentration range of 10–10,000ng/mL for decitabine and 5–500ng/mL for valdecitabine. The lower limit of quantitation (LLOQ) of decitabine and valdecitabine was 10 and 5ng/mL, respectively. The intra-day and inter-day precisions were less than 15% and the relative error (RE) was all within ±15%. The validated method was successfully applied to a pharmacokinetics study in rats after either decitabine or valdecitabine orally administrated to the Sprague-Dawley rats. [Copyright &y& Elsevier]