Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Plant J ; 118(6): 2188-2201, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38581688

RESUMO

Moving from sole cropping to intercropping is a transformative change in agriculture, contributing to yield. Soybeans adapt to light conditions in intercropping by adjusting the onset of reproduction and the inflorescence architecture to optimize reproductive success. Maize-soybean strip intercropping (MS), maize-soybean relay strip intercropping (IS), and sole soybean (SS) systems are typical soybean planting systems with significant differences in light environments during growth periods. To elucidate the effect of changes in the light environment on soybean flowering processes and provide a theoretical basis for selecting suitable varieties in various planting systems to improve yields, field experiments combining planting systems (IS, MS, and SS) and soybean varieties (GQ8, GX7, ND25, and NN996) were conducted in 2021 and 2022. Results showed that growth recovery in the IS resulted in a balance in the expression of TERMINAL FLOWER 1 (TFL1) and FLOWERING LOCUS T (FT) in the meristematic tissues of soybeans, which promoted the formation of new branches or flowers. IS prolonged the flowering time (2-7 days) and increased the number of forming flowers compared with SS (93.0 and 169%) and MS (67.3 and 103.3%) at the later soybean flowering stage. The higher carbon and nitrogen content in the middle and bottom canopies of soybean contributed to decreased flower abscission by 26.7 and 30.2%, respectively, compared with SS. Canopy light environment recovery promoted branch and flower formation and transformation of flowers into pods with lower flower-pod abscission, which contributed to elevating soybean yields in late-maturing and multibranching varieties (ND25) in IS.


Assuntos
Flores , Glycine max , Luz , Zea mays , Glycine max/fisiologia , Glycine max/genética , Glycine max/crescimento & desenvolvimento , Zea mays/fisiologia , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Flores/fisiologia , Flores/genética , Flores/crescimento & desenvolvimento , Agricultura/métodos , Produção Agrícola/métodos , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Produtos Agrícolas/crescimento & desenvolvimento
2.
J Sci Food Agric ; 104(7): 3865-3882, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38217341

RESUMO

BACKGROUND: Soil is a key foundation of crop root growth. There are interactions between root system and soil in multiple ways. The present study aimed to further explore the response of root distribution and morphology to soil physical and chemical environment under maize (Zea mays L.) soybean (Glycine Max L. Merr.) relay strip intercropping (MS) An experiment was carried out aiming to examine the effects of nitrogen (N) applications and interspecific distances on root system and soil environment in MS. The two N application levels, referred to as no N application (NN) and conventional N application (CN), were paired with different interspecific distances: 30, 45 and 60 cm (MS30, MS45 and MS60) and 100 cm of monoculture maize and soybean (MM/SS100). RESULTS: The results demonstrated that MS45 increased the distribution of soil aggregates (> 2 mm) near the crop roots and maize soil nutrients status, which increased by 20.3% and 15.6%. Meanwhile, MS reduced soil bulk density, increased soil porosity and improved soil oxygen content. Optimization of the soil environment facilitated root growth. The MS45 achieved a better result on root distribution and morphology than the other configuration and also increased land productivity. CONCLUSION: Relay intercropped soybean with maize in interspecific row spacing of 45 cm, improved soil physicochemical environment, reshaped root architecture and optimized root spatial distribution of crops to achieve greater land productivity. © 2024 Society of Chemical Industry.


Assuntos
Agricultura , Solo , Solo/química , Agricultura/métodos , Glycine max , Zea mays , Nitrogênio/análise
3.
J Sci Food Agric ; 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38980001

RESUMO

BACKGROUND: Relay intercropping of maize and soybean can improve land productivity. However, the mechanism behind N2O emissions in this practice remains unclear. A two-factor randomized block field trial was conducted to reveal the mechanism of N2O emissions in a full additive maize-soybean relay intercropping. Factor A was three cropping systems - that is, monoculture maize (Zea mays L.), monoculture soybean (Glycine max L. Merr.) and maize-soybean relay intercropping. Factor B was different N supply, containing no N, reduced N and conventional N. Differences in N2O emissions, soil properties, rhizosphere bacterial communities and yield advantage were evaluated. RESULTS: The land equivalent ratio was 1.55-2.44, and the cumulative N2O emission ( C E N 2 O $$ \mathrm{C}{\mathrm{E}}_{{\mathrm{N}}_2\mathrm{O}} $$ ) was notably lower by 60.2% in intercropping than in monoculture, respectively. Reduced N declined C E N 2 O $$ \mathrm{C}{\mathrm{E}}_{{\mathrm{N}}_2\mathrm{O}} $$ without penalty on the yield advantages. The relay intercropping shifted soil properties - for example, soil organic matter, total N, NH 4 + $$ {\mathrm{NH}}_4^{+} $$ and protease activity - and improved the soil microorganism community - for example, Proteobacteria and Acidobacteria. Intercropping reduced C E N 2 O $$ \mathrm{C}{\mathrm{E}}_{{\mathrm{N}}_2\mathrm{O}} $$ by directly suppressing nirS- and amoA-regulated N2O generation during soil N cycling, or nirS- and amoA-mediated soil properties shifted to reduce C E N 2 O $$ \mathrm{C}{\mathrm{E}}_{{\mathrm{N}}_2\mathrm{O}} $$ indirectly. Reduced N directly reduced C E N 2 O $$ \mathrm{C}{\mathrm{E}}_{{\mathrm{N}}_2\mathrm{O}} $$ by decreasing soil N content and reducing soil microorganism activities to alleviate N2O produced in soil N cycling. CONCLUSION: Conducting a full additive maize-soybean relay intercropping with reduced nitrogen supply provides a way to alleviate N2O emissions without the penalty on the yield advantage by changing rhizosphere bacterial communities and soil N cycling. © 2024 Society of Chemical Industry.

4.
BMC Plant Biol ; 23(1): 38, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36646997

RESUMO

Applying Biochar (BC) or biofertilizers (BF) are potential approaches to reduce the nitrogen input and mitigate soil degradation in the maize soybean relay strip intercropping system (IS). In 2019 and 2020, a two-factor experiment was carried out to examine the effects of BC and BF on soil productivity and yield production in IS. 4 N input levels (8.4, 22.5, 45 kg, and 67.5 kg ha - 1) referred to as N0, N1, N2, and N3 were paired with various organic treatments, including BC (150 kg ha - 1), BF (300 kg ha - 1), and without organic amendments (CK). The results demonstrated that, despite BF decreasing the biomass and N distribution into grains, BF performed better on improved soybean yield (5.2-8.5%) by increasing the accumulation of soybean biomass (7.2 ~ 11.6%) and N (7.7%). Even though BC and BF have a detrimental effect on soybean nitrogen fixation by reducing nodule number and weight, the values of soybean nitrogenase activity and nitrogen fixation potential in BF were higher than those in BC. Additionally, BF performs better at boosting the soil's nitrogen content and nitrate reductase and urease activity. BF increased the concentration of total N, soil organic matter, Olsen-phosphorus, and alkaline hydrolyzable N in the soil by 13.0, 17.1, 22.0, and 7.4%, respectively, compared to CK. Above all, applying BF combination with N2 (45 kg ha - 1 N) is a feasible strategy to raise crop grain output and keep soil productivity over the long term in IS.


Assuntos
Agricultura , Glycine max , Glycine max/metabolismo , Zea mays/metabolismo , Nitrogênio/metabolismo , Fertilizantes , Solo
5.
Beilstein J Org Chem ; 17: 2840-2847, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34956406

RESUMO

A novel hemicucurbituril-based macrocycle, alternately consisting of amidobenzene and 2-imidazolidione moieties was designed and synthesized. Based on the fragment coupling strategy, nitrobenzene-containing hemicucurbituril was firstly prepared facilely under alkaline environment, and reduction of the nitro groups produced the desired amidobenzene-containing hemicucurbituril. As an original fluorescent chemosensor, it exhibited strong interactions with Fe3+ over other metal cations. The experimental evidence of fluorescence spectra suggested that a 1:1 complex was formed between this macrocycle and Fe3+ with an association constant up to (2.1 ± 0.3) × 104 M-1. Meanwhile, this macrocycle showed no obvious or only slight enhancement of the fluorescence intensity with selected anions.

6.
Colloids Surf B Biointerfaces ; 239: 113969, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38749168

RESUMO

In this study, poly (lactic acid)/zinc-doped nano hydroxyapatite (PLA/nano-ZnHA) composite microspheres were prepared and formed into injectable bone paste with sodium alginate (SA) and polyvinyl alcohol (PVA) for bone defect repair. The effect of component of bone paste on injectability and zinc doping content related biological properties were mainly discussed. An injectable bone paste of PLA/nano-ZnHA composite microspheres (CM) was formed in mass ratio of (2.5-25):(0.25-4): (0-2.5):(20-65) of CM, SA, PVA and water with the favorable injectability (average force:4.46±1.72 N). In vitro 5%-10% zinc doping content displayed significantly higher promotion on cell proliferation and osteogenic differentiation than 15%-20% zinc doping content. Furthermore, in vivo the significant promoting effect of 0-5% zinc doping in ZnHA on bone repair was observed. Although 5% zinc doping content did not show a significant enhancement in bone volume/tissue volume (BV/TV), it has the ability to improve the bone mineral density (BMD) in early stage of bone repair compared with the 0% zinc doping content. The PLA/nano-ZnHA composite microsphere injectable paste with convenient surgical operation and well filling ability has the potential to become a competitive tissue repair material.


Assuntos
Durapatita , Microesferas , Poliésteres , Crânio , Zinco , Poliésteres/química , Durapatita/química , Durapatita/farmacologia , Zinco/química , Zinco/farmacologia , Animais , Crânio/efeitos dos fármacos , Crânio/patologia , Proliferação de Células/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Injeções , Diferenciação Celular/efeitos dos fármacos
7.
Materials (Basel) ; 16(12)2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37374478

RESUMO

Nickel-based alloys have demonstrated significant promise as structural materials for Gen-IV nuclear reactors. However, the understanding of the interaction mechanism between the defects resulting from displacement cascades and solute hydrogen during irradiation remains limited. This study aims to investigate the interaction between irradiation-induced point defects and solute hydrogen on nickel under diverse conditions using molecular dynamics simulations. In particular, the effects of solute hydrogen concentrations, cascade energies, and temperatures are explored. The results show a pronounced correlation between these defects and hydrogen atoms, which form clusters with varying hydrogen concentrations. With increasing the energy of a primary knock-on atom (PKA), the number of surviving self-interstitial atoms (SIAs) also increases. Notably, at low PKA energies, solute hydrogen atoms impede the clustering and formation of SIAs, while at high energies, they promote such clustering. The impact of low simulation temperatures on defects and hydrogen clustering is relatively minor. High temperature has a more obvious effect on the formation of clusters. This atomistic investigation offers valuable insights into the interaction between hydrogen and defects in irradiated environments, thereby informing material design considerations for next-generation nuclear reactors.

8.
Colloids Surf B Biointerfaces ; 228: 113418, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37348268

RESUMO

In this study, polylactic acid (PLA) microspheres were used as the raw material to construct bulk implants with surface microtopography through hot pressing and heat treatment, and the microtopographical structures were regulated through the sizes of the PLA microspheres. The surface microtopographies of PLA implants were successfully constructed using micron-sized bulges, which showed a wave-like structure. The ridge width of bulges ranged from 1.64 ± 0.16 µm to 82.52 ± 14.38 µm and the valley depth ranged from 0.49 ± 0.07 µm to 37.35 ± 6.78 µm according to the sizes of microspheres. The nanoindentation tests showed that the modulus and hardness of PLA implants were gradually increased with the decrease in microsphere sizes. The surface microtopography resulted in a slight increase in the hydrophobicity of the PLA implants, but no significant differences were observed. Cells cultured on the implant surface with microtopography exhibited varying morphological responses, and significantly increased osteogenic activity was observed relative to a PLA flat film. This study demonstrated that the surface microtopography derived from PLA microspheres could regulate cellular response and activate osteogenic properties of PLA implants.


Assuntos
Poliésteres , Polímeros , Polímeros/química , Poliésteres/farmacologia , Osteogênese , Próteses e Implantes , Propriedades de Superfície
9.
Research (Wash D C) ; 6: 0156, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37287892

RESUMO

Conventionally, to produce a linear motion, one motor's stator is employed to drive one runner moving forward or backward. So far, there is almost no report of one electromechanical motor or piezoelectric ultrasonic motor that can directly generate two symmetrical linear motions, while this function is desired for precise scissoring and grasping in the minimally invasive surgery field. Herein, we report a brand-new symmetric-actuating linear piezoceramic ultrasonic motor capable of generating symmetrical linear motions of two outputs directly without additional mechanical transmission mechanisms. The key component of the motor is an (2 × 3) arrayed piezoceramic bar stator operating in the coupled resonant mode of the first longitudinal (L1) and third bending (B3) modes, leading to symmetric elliptical vibration trajectories at its two ends. A pair of microsurgical scissors is used as the end-effector, demonstrating a very promising future for high-precision microsurgical operations. The sliders of the prototype show the following features: (a) symmetrical, fast relative moving velocity (~1 m/s) outward or inward simultaneously; (b) high step resolution (40 nm); and (c) high power density (405.4 mW/cm3) and high efficiency (22.1%) that are double those of typical piezoceramic ultrasonic motors, indicating the full capacity of symmetric-actuating linear piezoceramic ultrasonic motor working in symmetric operation principle. This work also has enlightening significance for future symmetric-actuating device designs.

10.
Ann Palliat Med ; 10(6): 6753-6759, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34237975

RESUMO

BACKGROUND: Placenta previa is one dangerous disease which threatens the health of pregnant women and their fetuses. The purpose of this study was to evaluate the clinical value of ultrasound combined with magnetic resonance imaging (MRI) in screening for placenta previa complicated by placenta accreta. METHODS: Seventy patients with abnormal fetal position admitted to our hospital from January 2019 to January 2020 were selected for the study. Patients were diagnosed by ultrasound alone, MRI alone, and ultrasound combined with MRI. Diagnostic accuracy, sensitivity, specificity and false positive and negative diagnosis rates were evaluated against the postoperative pathological examinations of the patients. RESULTS: The diagnostic accuracy, sensitivity and false negative rate for ultrasound combined with MRI were 86.27%, 97.78% and 72.00%, respectively. These results were significantly superior to those of MRI or ultrasound alone (P<0.05). The specificity and false positive rate for ultrasound combined with MRI were 13.73% and 5.26%, respectively, which were not significantly different from those for MRI or ultrasound alone (P>0.05). CONCLUSIONS: Compared with ultrasound or MRI alone, ultrasound combined with MRI has higher accuracy and sensitivity in the diagnosis of placenta previa with placenta accreta, along with lower false positive diagnosis rates. These findings are clinically important for improving the diagnostic efficiency.


Assuntos
Placenta Acreta , Placenta Prévia , Feminino , Humanos , Imageamento por Ressonância Magnética , Placenta Acreta/diagnóstico por imagem , Placenta Prévia/diagnóstico por imagem , Gravidez , Estudos Retrospectivos , Sensibilidade e Especificidade , Ultrassonografia
11.
Front Plant Sci ; 12: 818327, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35069671

RESUMO

Insufficient and unbalanced biomass supply inhibited soybean [Glycine max (L.) Merr.] yield formation in the maize-soybean relay strip intercropping (IS) and monoculture soybean (SS). A field experiment was conducted to explore the soybean yield increase mechanism of DA-6 in IS and SS treatments. In this 2-year experiment, compact maize "Denghai 605" and shade-tolerant soybean "Nandou 25" were selected as cultivated materials. DA-6 with four concentrations, i.e., 0 mg/L (CK), 40 mg/L (D40), 60 mg/L (D60), and 80 mg/L (D80), were sprayed on soybean leaves at the beginning of flowering stage of soybean. Results showed that DA-6 treatments significantly (p < 0.05) increased soybean grain yield, and the yield increase ratio was higher in IS than SS. The leaf area index values and net photosynthesis rate of IS peaked at D60 and were increased by 32.2-49.3% and 24.1-27.2% compared with the corresponding CK. Similarly, DA-6 treatments increased the aboveground dry matter and the amount of soybean dry matter accumulation from the R1 stage to the R8 stage (VDMT) and highest at D60 both in IS and SS. D60 increased the VDMT by 29.0-47.1% in IS and 20.7-29.2% in SS. The TR G at D60 ranged 72.4-77.6% in IS and 61.4-62.5% in SS. The MDA content at D60 treatment was decreased by 38.3% in IS and 25.8% in SS. The active grain-filling day in IS was about 7 days longer than in SS. In D60 treatment, the Vmean and Vmax increased by 6.5% and 6.5% in IS and 5.7% and 4.3% in SS compared with the corresponding CK. Although the pod number and hundred-grain weight were significantly (p < 0.05) increased by DA-6 treatments, the grains per pod were maintained stable. The pod number and hundred-grain weight were increased by 30.1-36.8% and 4.5-6.7% in IS and 6.3-13% and 3.6-5.6% in SS. Thus, the grain yield at D60 was increased by 36.7-38.4% in IS and 21.7-26.6% in SS. DA-6 treatments significantly (p < 0.05) increased soybean grain yield and peaked D60 treatments both in IS and SS.

12.
J Chromatogr A ; 1623: 461154, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505273

RESUMO

Chiral stationary phases (CSPs) have always been research hotspot in enantiomer separation. Currently, most of the CSPs are based on silica platform. In this research, monodisperse, porous glycidyl methacrylate-divinylbenzene copolymer particles (poly(GMA-DVB)) were designed and prepared. Then the GMA was further reacted with ethylenediamine to introduce amino groups onto the polymer, which provide anchoring sites for cellulose derivatives. Herein, Cellulose-tris (3,5-dimethylphenylcarbamate) (CDMPC) was successfully coated onto the polymer microspheres, achieving a stable and successful CSP. The porous structure and the surface moieties of the CSPs were studied in detail. The chromatographic separation was optimized. Hexaconazole,methyl DL-mandelate,benzoin and tebuconazole have been successfully separated on the CSP column, with column efficiency as high as 10,200 plates/m, which is comparable with some silica-based CSPs. The research has indicated that the poly(GMA-DVB) is a promising candidate for constructing CSPs for chiral separation.


Assuntos
Celulose/análogos & derivados , Microesferas , Fenilcarbamatos/química , Polímeros/química , Celulose/química , Cromatografia Líquida de Alta Pressão/métodos , Compostos de Epóxi/química , Metacrilatos/química , Porosidade , Dióxido de Silício/química , Estereoisomerismo , Triazóis/química , Compostos de Vinila/química
13.
Food Chem ; 307: 125531, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31644979

RESUMO

In the present study, submicrometer flow-through silica microspheres (Sub-FTSiO2) was for the first time obtained via a suspension polymerization method coupled with sol-gel transition and phase separation. The Sub-FTSiO2 was characteristic of rich mesopores, penetrable macropores and small particle size, which would be beneficial to fast mass transfer, low column backpressure and high column efficiency. It was directly used as the hydrophilic interaction liquid chromatographic (HILIC) stationary phase, and the fast separation of seven water-soluble vitamins in 2.2 min was realized. The proposed method was successfully applied to the determination of water-soluble vitamins in two functional beverages on the market. The prepared Sub-FTSiO2 was well demonstrated for fast HILIC, and would be potential as the stationary phase matrix for fast liquid chromatography in diverse separation modes.


Assuntos
Cromatografia Líquida/métodos , Microesferas , Dióxido de Silício/química , Vitaminas/isolamento & purificação , Ácido Ascórbico/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Complexo Vitamínico B/isolamento & purificação , Vitaminas/química , Água/química
14.
Research (Wash D C) ; 2019: 8232097, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31922139

RESUMO

Fast actuation with nanoprecision over a large range has been a challenge in advanced intelligent manufacturing like lithography mask aligner. Traditional stacked stage method works effectively only in a local, limited range, and vibration coupling is also challenging. Here, we design a dual mechanism multimodal linear actuator (DMMLA) consisted of piezoelectric and electromagnetic costator and coslider for producing macro-, micro-, and nanomotion, respectively. A DMMLA prototype is fabricated, and each working mode is validated separately, confirming its fast motion (0~50 mm/s) in macromotion mode, micromotion (0~135 µm/s) and nanomotion (minimum step: 0~2 nm) in piezoelectric step and servomotion modes. The proposed dual mechanism design and multimodal motion method pave the way for next generation high-precision actuator development.

15.
Sci Adv ; 5(11): eaax1782, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31976367

RESUMO

Designing topological and geometrical structures with extended unnatural parameters (negative, near-zero, ultrahigh, or tunable) and counterintuitive properties is a big challenge in the field of metamaterials, especially for relatively unexplored materials with multiphysics coupling effects. For natural piezoelectric ceramics, only five nonzero elements in the piezoelectric matrix exist, which has impeded the design and application of piezoelectric devices for decades. Here, we introduce a methodology, inspired by quasi-symmetry breaking, realizing artificial anisotropy by metamaterial design to excite all the nonzero elements in contrast to zero values in natural materials. By elaborately programming topological structures and geometrical dimensions of the unit elements, we demonstrate, theoretically and experimentally, that tunable nonzero or ultrahigh values of overall effective piezoelectric coefficients can be obtained. While this work focuses on generating piezoelectric parameters of ceramics, the design principle should be inspirational to create unnatural apparent properties of other multiphysics coupling metamaterials.

16.
Sci Rep ; 7(1): 8592, 2017 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-28819271

RESUMO

The magnetic flux gate sensors based on Faraday's Law of Induction are widely used for DC or extremely low frequency magnetic field detection. Recently, as the fast development of multiferroics and magnetoelectric (ME) composite materials, a new technology based on ME coupling effect is emerging for potential devices application. Here, we report a magnetoelectric flux gate sensor (MEFGS) for weak DC magnetic field detection for the first time, which works on a similar magnetic flux gate principle, but based on ME coupling effect. The proposed MEFGS has a shuttle-shaped configuration made of amorphous FeBSi alloy (Metglas) serving as both magnetic and magnetostrictive cores for producing a closed-loop high-frequency magnetic flux and also a longitudinal vibration, and one pair of embedded piezoelectric PMN-PT fibers ([011]-oriented Pb(Mg,Nb)O3-PbTiO3 single crystal) serving as ME flux gate in a differential mode for detecting magnetic anomaly. In this way, the relative change in output signal of the MEFGS under an applied DC magnetic anomaly of 1 nT was greatly enhanced by a factor of 4 to 5 in comparison with the previous reports. The proposed ME flux gate shows a great potential for magnetic anomaly detections, such as magnetic navigation, magnetic based medical diagnosis, etc.

SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa