Search

The addition of organic matter via green manure rotations in paddy rice has previously been proposed as a smart agricultural practice to maintain soil productivity and support environmental sustainability. However, to date, only a few studies have assessed quantitatively the impact of green manure application on the interactions between agronomic management practices, soil fertility, and crop production. In this study, 800 pairs of data from 108 studies, conducted in the Yangtze River agricultural region of China were assessed, and a meta-analysis was carried out to evaluate and quantify the effect of green manure application on rice yield and soil properties. Firstly, compared to a winter fallow system, amendment with green manure significantly increased paddy rice yield and soil organic carbon (SOC) by 8.1% and 8.4%, respectively. Secondly, analysis using a Random Forest model revealed that paddy rice type, green manure application rate and duration, mineral and organic N fertilizer rate, and initial SOC and pH were identified as the main drivers for paddy rice yield and SOC change. Finally, Marginal Benefit Analysis (MBA) revealed that green manure application rates for production in early rice of double cropping rice (ER) and single rice (SR) were approximately of 20 and 26 t ha-1 respectively. and further, for carbon sequestration, that the optimal rate was ~25 t ha-1. It should, however, be noted that green manure application to soils with already high SOC level might result in the soil becoming a net C source. The study supported the scientific and quantitative indicators for achieving the best benefits of paddy rice yield and SOC increase after green manure application.

With the improvement of people’s living standard, the fast-increase demand for agricultural products with high quality is endless. Therefore, developing accurate and rapid detection methods for agr...

Magnetic brain stimulation has greatly contributed to the advancement of neuroscience. However, challenges remain in the power of penetration and precision of magnetic stimulation, especially in small animals. Here, a novel combined magnetic stimulation system (c-MSS) was established for brain stimulation in mice. The c-MSS uses a mild magnetic pulse sequence and injection of superparamagnetic iron oxide (SPIO) nanodrugs to elevate local cortical susceptibility. After imaging of the SPIO nanoparticles in the left prelimbic (PrL) cortex in mice, we determined their safety and physical characteristics. Depressive-like behavior was established in mice using a chronic unpredictable mild stress (CUMS) model. SPIO nanodrugs were then delivered precisely to the left PrL cortex using in situ injection. A 0.1 T magnetic field (adjustable frequency) was used for magnetic stimulation (5 min/session, two sessions daily). Biomarkers representing therapeutic effects were measured before and after c-MSS intervention. Results showed that c-MSS rapidly improved depressive-like symptoms in CUMS mice after stimulation with a 10 Hz field for 5 d, combined with increased brain-derived neurotrophic factor (BDNF) and inactivation of hypothalamic-pituitary-adrenal (HPA) axis function, which enhanced neuronal activity due to SPIO nanoparticle-mediated effects. The c-MSS was safe and effective, representing a novel approach in the selective stimulation of arbitrary cortical targets in small animals, playing a bioelectric role in neural circuit regulation, including antidepressant effects in CUMS mice. This expands the potential applications of magnetic stimulation and progresses brain research towards clinical application.

Amorphous Co-rich microwires with excellent soft magnetic and mechanical properties produced by melt-extraction technique are emerging as a multifunctional material for a variety of applications ranging from ultrasensitive magnetic field sensors to structural health self-monitoring composites. There is a pressing need for enhancing these properties to make the microwires practical for integration into new technologies. Conventional heat treatments at temperature below crystallization may improve the magnetic softness of an as-quenched amorphous wire, but usually deteriorate the good mechanical characteristic of the wire due to crystallization. To overcome this, we propose a new approach that utilizes the advantages of a multi-step Joule current annealing method to design novel (nanocrystal, amorphous)/amorphous core/shell structures directly from as-quenched amorphous microwires. These results show that the density and size of nanocrystals in the core can be optimized by controlling the Joule current intensity, resulting in the large enhancement of soft magnetic and giant magneto-impedance properties, while the amorphous shell preserves the excellent mechanical strength of the microwire. This study also provides a new pathway for the design of novel core/shell structures directly from rapidly quenched amorphous magnetic materials that are currently exploited in high frequency transformers, sensing and cooling devices.

Inosine monophosphate (IMP) was considered to be an important component of meat flavor and an important indicator for evaluating the quality of meat products. This paper developed a novel dual-enzyme biosensor for the quantitative detection of inosinic acid to assess meat quality. Using the conductivity of MXene materials and the ability of Au@Pt nanoflowers to catalyze the oxidation of H2O2, a dual-enzyme biosensor was assembled and prepared for sensitive and rapid detection of IMP. The MXene-Ti3C2Tx material had 2D nanostructure similar to that of graphene, as well as metal conductivity and good biocompatibility. MXene was used as a carrier for 5′-nucleotidase and xanthine oxidase, with good biological environment and stable microenvironment. Bimetallic nanoflowers with a core-shell structure had better ability to catalyze H2O2 than the single metal. The double-enzyme hydrolyzed IMP to produce the H2O2. The Au@Pt nanoflowers of the sensor can catalyze the decomposition of H2O2, which causes electron transfer to produce current change. Therefore, the content of IMP is indirectly obtained by monitoring the current change. The results showed that the linear range of the double-enzyme biosensor was 0.04~17 g L−1, the correlation coefficient was 0.9964, and the detection limit was 2.73 ng mL−1. The biosensor had great reproducibility and stability. Compared with high-performance liquid chromatography, biosensors could quickly and accurately detect the content of inosine monophosphate in meat, and provided a better method to detect the quality index of meat products.

We have designed a new magnetic bed structure with desirable table-like magnetocaloric effect (MCE) by using three kinds of soft ferromagnetic Gd-Al-Co microwire arrays with different Curie temperatures ($T_C$). The $T_C$ interval of these three wires is ~10 K and the designed new structure named Sample A. This sample shows a smooth table-like magnetic entropy change ($\Delta S_M$) at high applied field change ($\mu_0 \Delta H=5 T$) ranging from ~92 K to ~107 K. The maximum entropy change ($-\Delta S_M^{\rm max}$) and refrigerant capacity (RC) for Sample A at $\mu_0 \Delta H=5 T$ are calculated to be ~9.42 Jkg$^{-1}$K$^{-1}$ and ~676 Jkg$^{-1}$. The calculated curves of $-\Delta S_M(T)$ and the corresponding experimental data match well with each other, suggesting that the desirable magnetocaloric properties of the microwire arrays can be designed. Simulation shows that the RC values of the designed systems increase when increasing the interval of $T_C$. The table-like MCE and the enhanced heat-transfer efficiency due to the enhanced surface areas of the microwires make this newly designed magnetic bed very promising for use in energy-efficient magnetic refrigerators.

Through designing the composition and processing approach, the non-equiatomic (Gd36Tb20Co20Al24)100-xFex (x = 0, 1, 2 and 3 at.%) high-entropy-metallic-glass (HE-MG) alloy microwires were successfully fabricated by melt-extraction technique. The microstructure and magnetocaloric properties of the microwires were systematically investigated. The microwires possess tunable Curie temperatures, i.e. 81–108 K, above the typical rare-earth (RE) containing HE-MG reports. The high Curie temperatures are attributed to the designed composition. Magnetocaloric response peak values of Fe-containing GdTbCoAl alloy microwires range 7.6–8.9 J kg−1 K−1 (5 T), which are comparable to those of many outstanding RE-containing magnetocaloric HE-MGs. The characteristics of the melt-extraction method, combining with compositional effects, favor the formation of amorphous and nanocrystalline phases. The increase in the cooling efficiency for microwires with higher Fe content can be attributed to the broadening of the Curie temperature distribution induced by the composition difference between nanocrystalline phase and amorphous matrix. The designed composition and the melt-extraction processing approach for Fe-containing GdTbCoAl alloys can tune their Curie temperatures towards a temperature range of natural gas liquefaction and improve their magnetocaloric properties. This demonstrates that Fe-containing GdTbCoAl HE-MG composite microwires have great potential as high-performance magnetic refrigerants. National Natural Science Foundation of China 51871076, 51671070, 51801044, 51827801 China Postdoctoral Science Foundation 2019M661275 Agencia Estatal de Investigación PID2019-105720RB-I00 Universidad de Sevilla US-1260179 Junta de Andalucía P18-RT-746 China Scholarship Council 201906120183

Literature search and scientometrics analysis method

The polycrystalline Mn1.26Fe0.60P0.48Si0.52 microwires were successfully fabricated for the first time by the melt-extraction technique, and their magnetic and magnetocaloric properties were investigated systematically. The structural analysis shows that the microwires possess a hexagonal phase with Fe2P type, with a homogeneous composition distribution. Magnetometry measurements show that the microwires undergo a weak first-order magnetic phase transition at a temperature of 142 K. The maximum magnetic entropy change of the microwires reaches 4.64 Jkg-1K-1 for a field change of 5 T. These low-cost Mn1.26Fe0.60P0.48Si0.52 microwires are promising for active magnetic refrigeration in the liquid nitrogen temperature range.

In this work, a novel dual signal amplification strategy for aptasensor employing reduced graphene with silver nanoparticles and prussian blue-gold nanocomposites was developed for detection of acetamiprid. To improve the sensitivity of aptasensors, reduced graphene oxide-silver nanoparticles (rGo-AgNPs) were modified on a bare glassy carbon electrode surface, which provided a large specific surface area for subsequent material immobilization and amplified current signal. The electrical signal output and sensitivity of the aptasensor was significantly improved after the immobilization of prussian blue-gold nanoparticles (PB-AuNPs) as a catalyst for the redox reaction. The analysis experiment exhibited that it had super-high sensitivity with a detection limit of 0.30 pM (S/N = 3), which met the requirements of the vast majority of daily leaf vegetable testing. Under optimized conditions, the proposed aptasensor showed a wide linear detection range from 1 pM to 1 μM. This aptasensor also had good stability and high selectivity for acetamiprid detection without an interfering effect of some other pesticides. The proposed aptasensor displayed good recovery rates in real samples, which proposed a new method for constructing electrochemical sensors and provided a novel tool for rapid, sensitive analysis of pesticides with low cost.

Shanshan Ma,1,* Zibin Wang,2,* Yu Guo,1 Peng Wang,3 Zukun Yang,1 Liping Han,1 Jianfei Sun,4 Yang Xia1,4 1Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, Jiangsu 210029, China; 2Analysis and Test Center, Nanjing Medical University, Nanjing, Jiangsu211166, China; 3Department of Sports Medicine and Adult Reconstructive Surgery, Drum Tower Hospital Affiliated to Medical School of Nanjing University, Nanjing, Jiangsu 210008, China; 4Jiangsu KeyLaboratory for Biomaterials andDevices, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu210096, China *These authors contributed equally to this work Purpose: Electrospun scaffolds have been studied extensively for their potential use in bone tissue engineering. However, their hydrophobicity and relatively low matrix stiffness constrain their osteoinduction capacities. In the present study, we studied polymer electrospun scaffolds coated with hydrophilic hematite nanoparticles (αFeNPs) constructed using layer-by-layer (LbL) assembly to construct a bioactive interface between the scaffolds and cells, to improve the osteoinduction capacities of the scaffolds.Materials and methods: The morphology of the αFeNPs was assessed. Surface properties of the scaffolds were tested by X-ray photoelectron spectroscopy (XPS), surface water contact angle, and in vitro protein adsorption test. The stiffness of the coating was tested using an atomic force microscope (AFM). In vitro cell assays were performed using rat adipose-derived stem cells (ADSCs).Results: Morphology characterizations showed that αFeNPs assembled on the surface of the scaffold, where the nano assemblies improved hydrophilicity and increased surface roughness, with increased surface stiffness. Enhanced initial ADSC cell spread was found in the nano assembled groups. Significant enhancements in osteogenic differentiation, represented by enhanced alkaline phosphatase (ALP) activities, elevated expression of osteogenic marker genes, and increased mineral synthesis by the seeded ADSCs, were detected. The influencing factors were attributed to the better hydrophilicity, rougher surface topography, and harder interface stiffness. In addition, the presence of nanoparticles was believed to provide better cell adhesion sites.Conclusion: The results suggested that the construction of a bioactive interface by LbL assembly using αFeNPs on traditional scaffolds should be a promising method for bone tissue engineering. Keywords: layer-by-layer assembly, osteogenesis, nanotechnology, bone tissue engineering, surface, αFeNPs &nbsp

树干表面CO2通量是森林生态系统碳收支的重要组成部分，对全球碳平衡产生重要影响。近年来，全球变化导致植物光合产物供应发生改变，这将影响树干表面CO2通量。然而，关于光合产物供应如何影响树干表面CO2通量的机理仍不清楚。以盆栽杉木（Cunninghamia lanceolata）幼苗为研究对象，采用遮光方法减少光合产物供应，通过自制呼吸气室，使用Li-8100测定树干表面CO2通量，并结合树干可溶性糖、淀粉和非结构性碳及树干温度等数据分析遮光对树干表面CO2通量的影响。结果表明：遮光后树干可溶性糖、淀粉和非结构性碳含量分别显著下降了55.0%、78.9%和64.3%。遮光处理阶段树干表面CO2通量平均下降39.9%，且下降幅度随着遮光时间的延长而增加；此外，遮光降低了树干表面CO2通量的温度敏感性。恢复光照后，树干表面CO2通量、树干可溶性糖、淀粉和非结构性碳含量以及树干温度均恢复至对照水平。可见，光合产物供应变化对树干表面CO2通量具有调控作用，而且能够通过调控树干表面CO2通量对温度变化的响应对全球碳循环产生重要影响。

Hyperspectral imaging technology combined with chemometrics were applied to detect fat content in peanut kernels. Four varieties of peanuts were scanned to acquire hyperspectral images by using a “push-broom” system. Then, the spectral data was extracted from hyperspectral images. Principal component analysis (PCA) was used to detect outliers. After outliers removed, five different pre-processing methods were used to preprocess spectral data. Successive projections algorithm (SPA) and regression coefficient (RC) were adopted to select effective wavelengths. Finally, based on the full wavelengths and the effective wavelengths, the models of partial least squares regression (PLSR), support vector machine regression (SVR) and multiple linear regression (MLR) were established respectively. Comparing these models, Baseline-SPA-MLR was the most excellent with determination coefficient (R2p) of 0.9736, root mean square errors (RMSEp) of 0.4635% and residual prediction deviation (RPD) of 6.1273 in the prediction set. All results in this study indicated that the combination of chemometrics and hyperspectral imaging technology provided an efficient and non-destructive method for detecting the fat content in peanut kernels.

The present study reported a dual-amplification electrochemical aptasensor for sensitive detection of profenofos (PFF) in vegetables. A screen-printed carbon electrode (SPCE) modified with graphitized multi-walled carbon nanotubes (MWCNTGr) and Au nanoshell was used as a test platform, which ensured a rapid detection process and showed a favorable electrochemical performance. MWCNTGr and Au nanoshell enhanced the electrical conductivity and the surface area, thus the detection signal was amplified. The affinity between PFF and its aptamer (Apt) was verified firstly by dot blot hybridization (DBH), and the result was exciting. Furthermore, the effects of the aptamers modified respectively with -NH2 and -SH on the current signal were compared with each other by cyclic voltammetry (CV), and results showed that the aptamers modified with -NH2 made the current signal change more obvious. Based on all above, a high-efficiency electrochemical aptasensor was fabricated with a wide linear range from 0.1–1 × 105 ng · ml−1 and a detection limit of 0.052 ng · ml−1 under the optimized conditions. This aptasensor had great specificity, stability and reproducibility. Hence, the developed aptasensor was successfully used to detect PFF in vegetables. The proposed method also has a potential for the detection of other organophosphorus pesticide (OPs).

The simulation of a complete manufacturing process to produce an aero engine case, including forging, rolling, and machining processes, is analyzed via finite element software. The deformation of the turning and drilling processes is quantitatively studied using the energy principles. Firstly, simulations of multi-stage forging of aero engine case and machining-induced residual stress are conducted and verified via the residual stresses test in order to provide the initial elastic strain energy condition prior to machining processes. The effects of blank forging-induced residual stress and machining-induced residual stress on the deformation of titanium alloys aero engine case are investigated. Secondly, a potential energy expression for the machining processes is developed. The predicted results of turning and drilling simulations indicate that there is an optimal process in which the deformation and potential energy decline rapidly compared with the other processes and finally, gradually stabilize at the end of the process.

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive. However, effective inspection and characterization metrology systems are needed to ensure the functional reliability of MEMS. This study presents a system based on digital holography as a tool for MEMS metrology. Digital holography has gained increasing attention in the past 20 years. With the fast development and decreasing cost of sensor arrays, resolution of such systems has increased broadening potential applications. Thus, it has attracted attention from both research and industry sides as a potential reliable tool for industrial metrology. Indeed, by recording the interference pattern between an object beam (which contains sample height information) and a reference beam on a CCD camera, one can retrieve the quantitative phase information of an object. However, most of digital holographic systems are bulky and thus not easy to implement on industry production lines. The novelty of the system presented is that it is lens-less and thus very compact. In this study, it is shown that the Compact Digital Holographic Microscope (CDHM) can be used to evaluate several characteristics typically consider as criteria in MEMS inspections. The surface profiles of MEMS in both static and dynamic conditions are presented. Comparison with AFM is investigated to validate the accuracy of the CDHM.

In order to investigate the influence of anneal treatment on the Co-based melt extraction wires, the soft magnetic properties and giant magnet-impedance （GMI） effect of the annealed Co75Fe40Si8B12Nb1 wire are investigated. Samples are prepared using melt extraction technology in vacuum and annealed at 450℃ without magnetic field or with miagntic field either longitudinal or transverse to the axis of wire of strength from 500 Oe to 4000 Oe，respectively. The magnetic softness and GMI response are measured using HP4192 Impedance Analyzer and Lakeshore7407 VSM. Test results show that the circular anisotropy and GMI response are reduced after longitudinal field anneal treatment. GMI profiles are single-peaked and the maximum impedance ratio ΔZ/Z is 131% and field sensitivity is 7%/Oe. The circular permeability and GMI response are improved after transverse field anneal treatments because of the increased circular anisotropy. At higher frequencies，the GMI profiles change from single-peaked to two-peaked after being annealed in strong transverse field. The circular permeability is increased and GMI effect gets stronger with the increase of current frequency and anneal field. The largest impedance ratio of 190% with a field sensitivity of 26%/Oe is obtained for the Co-based transverse field annealed wires at 10 MHz. The correlations between the circular permeability，the GMI effect and the current frequency are discussed in the light of a skin effect model.

Two-dimensional gold-assembled nanomaterials have garnered considerable interest in biomedical applications such as wearable sensors and flexible devices. The assembly can be accomplished via attractive interactions between gold nanoparticles (GNPs) and a standard polymer. It is highly desirable and a great challenge to develop a new assembly method that can provide formed materials with novel properties. In this work, we explored complementary DNA-functionalized gold nanoparticles (DNA-GNPs) as building blocks to establish multifunctional two-dimensional gold nanomaterials via layer-by-layer (LBL) assembly. We found that the DNA-mediated assembly endows GNP films with a superlattice and their sonic behavior could be regulated in a controllable manner through altering the sequence of SH-DNA and linker DNA, which was detected by the electric-induced ultrasound method. Our observation suggested that this DNA-mediated assembly of GNP films with controllable sonic behaviors could greatly promote the biomedical application of two-dimensional assembled-gold nanomaterials. Refereed/Peer-reviewed