Search

In degraded karst ecosystem, vegetation restoration efforts almost exclusively rely on planted seedlings, but this is not effective to maintain community diversity and resilience. As seed functional traits, seed dormancy and germination are key to community assembly. Unfortunately, these elements are commonly overlooked in restoring degraded ecosystems. This work classifies seed dormancy of 27 species with different life forms that are common on a degraded karst mountain. We examined the effects of temperature regime and light conditions on percentage germination and assessed the relationships between seed traits and germination index using a partial least squares regression (PLSR). Approximately 48% of the investigated species had physiological dormancy, 37% were non-dormant, 7% had morphophysiological dormancy, 4% had morphological dormancy and 4% had physical dormancy. We found that 94% (15 out of 16) species had maximum germination in warm temperature regimes (20/13 and 25/18 °C), while the remaining species required cool temperatures (10/4 °C). PLSR analysis indicated a significant positive correlation between seed mass and T

Background: Soybean is the most important oil crop globally; however, droughts are expected to seriously affect the growth and development of soybean in the context of climate change. Methods: In this study, polyethylene glycol (PEG) was used to simulate drought to explore the regulation of proline metabolism in soybean leaves under different degrees of drought stress at the seedling stage. Result: The results showed that the activities of ornithine aminotransferase and D1-pyrroline-5-carboxylate synthetase increased while the activities of proline dehydrogenase decreased with an increase in drought stress. During the same number of treatment days, the higher the degree of drought stress, the greater the increase or decrease in enzyme activity. The content of leaf proline increased gradually with an extension in stress time at PEG concentrations of 5% and 10%, first increased and then decreased at PEG concentrations of 15% and 20% and the peak value appeared on the 7th and 9th day, respectively.

In this study, the microstructure and hardness of the fusion zone of 316L-316LN stainless steel multi-pass gas tungsten arc welding (GTAW) weld joint were systematically investigated. The results showed that there were two typical inhomogeneous intermediate mixed zones distributed in the weld metal along the 316L (filler metal)-316LN (base metal) stainless steel multi-pass GTAW weld joint fusion boundary, one was the dendritic structure region, the other was the cellular structure region. The dendritic structure region was duplex structure with ferrite in vermicular morphology in austenite. By contrast, the cellular structure region exhibited cellular austenite structure with a small amount of ferrite particles at the cellular boundary triple points. It was found that the cellular boundary was high-density tangled dislocation structure with Cr and Mo segregation. Obvious residual strain was found to be concentrated adjacent to cellular boundaries due to the thermal expansion/shrinkage during the rapid solidification process. Because of the high-density dislocations, grain refinement and solute micro-segregation at the cellular boundaries, the microhardness of the cellular structure region was 239 HV, higher than that of the dendritic structure region (227 HV), and the nano-hardness exhibited a same trend, which was 3.03 GPa and 2.74 GPa, respectively.

Water Cherenkov detector array (WCDA) is one of the key parts of the Large High Altitude Air Shower Observatory (LHAASO), the construction of which was completed by the end of 2020. The WCDA covers a 78 000-m2 area and there exist 3120 large size photomultiplier tubes (PMTs) in three ponds: 8-in PMTs are used in WCDA pond No. 1 and 20-in PMTs are used in ponds No. 2 and No. 3. The front-end electronics (FEE) system based on multigain measurement technique is designed to achieve both high-precision time and charge measurements over a large dynamic range from single photon electron (S.P.E.) to 4000 P.E. (for water pond No. 1)/1800 P.E. (for water ponds No. 2 and No. 3). To achieve a high-quality clock distribution and phase alignment as well as mixed transmission of data, clock, and commands in one fiber over a long distance, an enhanced white rabbit (WR) technique is used. Testing of all the 350 FEE modules for the WCDA is presented in this article. Test results indicate that the charge resolution is better than 20% at S.P.E. and 1% at 1800/4000 P.E. and the time resolution is better than 300 ps root mean square (rms), which successfully meets the application requirement. All the FEE modules have been fabricated and installed for the LHAASO WCDA from 2018 to 2020, and the initial commissioning operation indicates that the FEEs function well.

In this research, the Cr/TiO2 composite coatings were formed in Na2HPO4 + NaOH + Cr2O3 by micro-arc oxidation (MAO) technology with different ratios of anodic and cathodic currents. Surface morpho...

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus spp. and Penicillium spp. and poses a threat to food safety. Biodegradation may be a promising strategy for reducing the OTA contamination in the future. In this study, Aspergillus niger strain W-35 was isolated from cereals and studied for its ability to degrade OTA. Results showed that the supernatant of W-35 could degrade OTA both in vitro and in commercial feeds after incubation at 37 °C for 12 h by 78.0 and 37.0%, respectively. Ochratoxin α (OTα) was assayed as a degradation product by HPLC-FLD. Furthermore, an enzyme specific for OTA degradation (ochratoxinase, OTase) obtained from W-35 was successfully expressed in Escherichia coli BL21, and degraded OTA at a rate of 85.1% for 12 h. These results indicated that this OTA degradation is enzymatic and that the responsible enzyme is extracellular OTase. Reliable degradation of OTA has the potential for wide-ranging applications in the food and feed industries.

Artificial intelligence (AI) is poised to significantly impact healthcare systems, including clinical diagnosis, healthcare administration and delivery, and public health infrastructures. In the context of the Quintuple Aim of healthcare (patient outcomes, cost reduction, population impact, provider wellness, and equity/inclusion), this chapter discusses the current state of AI in healthcare, focusing on issues that may inform the development of adaptive, efficient, and equitable governance frameworks for AI in healthcare. The chapter introduces prominent examples of clinical AI applications in recent years, highlighting their successes and extant limitations. It emphasizes the processes of clinical AI algorithm development, implementation, and provider adoption, noting important policy considerations for active maintenance and updating of such algorithms. It also focuses on the issue of bias in AI algorithms for healthcare by (1) illustrating how unrepresentative and/or inappropriate datasets can exacerbate health disparities and inequities, and (2) emphasizing the need for diversity, transparency, and accountability in algorithm development. It provides an overview of current national and international regulatory approaches for AI-driven medical devices. It concludes with recommendations of strategic goals for developers, healthcare providers, and governmental agencies to work towards cooperatively in building a productive and equitable future for AI in healthcare.

Objective This study aimed to characterize Neolithic human maxillary molars from archeological remains at the Jiaojia site, Shandong, China, and compare their ultrastructural features with sex and age-matched modern locals. Design Maxillary first (n = 86) and second (n = 80) molars in 5000-year-old individuals (n = 50) from the Jiaojia site were scanned by cone-beam computed tomography (CBCT). Sex and age-matched control groups were assigned from oral surgical patients at Shandong University. Images were analyzed for crown size, root length, root morphology, canal inter-orifice distances, mesiobuccal canal morphology, and second mesiobuccal (MB2) canal prevalence and location. Neolithic and modern values were compared statistically using Chi-squared and Mann-Whitney test at p Results Crown and root size were smaller, and canal inter-orifice distances were shorter in Neolithic maxillary molars than their modern counterparts. For mesiobuccal roots, Weine’s Type I single canals were the most prevalent in Neolithic and modern first and second molars. MB2 canal prevalence were not significantly different (p > .05) in Neolithic (53.3%) or modern (60.5%) first molars, and Neolithic (11.3%) or modern (21.3%) second molars. But, MB2 prevalence was significantly higher for modern than ancient male first (p = .032) and second (p = .005) molars. Additionally, MB2 were located more mesially and closer to MB1 in Neolithic than modern molars. Conclusions Maxillary molar root and canal morphology of ancient 5000-year-old remains at the Jiaojia site resemble that of local patients. A trend towards larger tooth size, and more dispersed MB2 canals over this short evolutionary period warrants additional investigation.

Stress corrosion cracking in light water reactor is one of the most important factors threatening the safe operation of nuclear power plants. Due to the severity, generality and various safety and economic problems caused by this phenomenon, it is necessary to establish a model for predicting the stress corrosion cracking growth rates. This paper provides an overview of three main methods for predicting stress corrosion cracking growth rates in recent decades, i.e., empirical, deterministic and calculation methods, which are introduced in detail. Empirical models describe classical statistical analysis and emerging artificial neural network method, both of which are based on a large number of experimental test data mining. They are convenient and relatively accurate in predicting, but require extensive, time-consuming and expensive tests for different service environments. Deterministic models aim to establish a theoretical relationship between crack growth rate and various influencing parameters by studying the stress corrosion cracking mechanism. Many scholars have proposed different mechanisms to scientifically explain the stress corrosion cracking phenomenon and propose corresponding crack growth rate models. Calculation models reveal the mechanism of crack initiation and propagation in different layers of materials by means of finite element method based on fracture mechanics and multiscale method based on quantum mechanics. They provide new idea for future research on stress corrosion cracking and bridge the quantitative mechanism or model, but no specific stress corrosion cracking growth rate model is formed. The article concludes with the prospect, aim and direction for stress corrosion cracking mechanism and prediction model.

The microstructural evolution and mechanical behavior of cast duplex stainless steels (CDSSs) at 400 °C for different thermal aging times were investigated by transmission electron microscope (TEM) and small punch test (SPT). The results showed that the spinodal decomposition in ferrite was the main reason for the decrease in toughness, and G-phase did not play an important role in the embrittlement process. The change of membrane stretching zone (Wm) played an important role in the SPT load-displacement curve before and after thermal aging. During the deformation process of Wm in the SPT, for thermal aging for 10,000 h, some completely curved slip bands were generated inside the ferrite phase, which had no contact with the δ/γ phase interface and belonged to the slip bands produced by the independent deformation of ferrite. The combined effect of the curved slip bands and stress concentration led to the initiation of obvious micro-cracks at the δ/γ phase interface. The micro-cracks propagated along the ferrite phase curved slip bands, and eventually penetrated the entire hardened ferrite phase.

The deformation behavior and fracture mechanism of cast duplex stainless steel tubular specimens under different tensile stages were investigated through experimental and numerical evaluation. The results showed that the axial stress was redistributed due to the necking of the tubular specimen, the axial stress near the internal wall was larger than those near the external wall, and its maximum axial stress was distributed between the internal wall and the center of the wall thickness. Microcracks and voids were initiated under the maximum shear stress along the δ/γ phase interface and propagated to the ferrite interior. The voids were connected and merged into the main crack through the propagation of the microcracks. Moreover, the main crack first propagated to the internal wall and then rapidly propagated to the external wall. The fracture morphology can be divided into three types: shear lip zones that can be found on both the internal and external walls, and shear lip zones that can be found on either only the internal wall or the external wall.

Hybrids with two-dimensional and three-dimensional nanostructures have attracted great interest in the construction of supercapacitor electrodes due to their unique structural features. Graphitic carbon nitride (g-C3N4) nanosheets are deposited on the surface of a nanoporous gold (NPG) film via an electrochemical method to form a hybrid electrode of NPG/g-C3N4 with an ultra-thin, ultra-light and good flexible characteristics. The electrochemical tests show that the hybrid electrode exhibits a good supercapacitive performance, such as an admirable specific capacitance (440 F g−1 at 2 A g−1) in 0.5 M Na2SO4 solution and a favorable cycling durability (maintaining 98% capacity after 10000 cycles). More interesting, the NPG/g-C3N4 electrode displays a striking enhancement of supercapacitive performance with the increase of bending angle. This superior property can be attributed to the unique nanosheets on nanoporous structure by a strong interfacial effect between the defected Au atoms of NPG and g-C3N4.

RIBLL Collaboration: et al., The mass of 27P is expected to impact the X-ray burst (XRB) model predictions of burst light curves and the composition of the burst ashes, but large uncertainties and inconsistencies still exist in the reported 27P masses. We have used the β-decay spectroscopy of 27S to determine the most precise mass excess of 7P to date to be −659(9)keV, which is 63 keV (2.3σ) higher and a factor of 3 more precise than the value recommended in the 2016 Atomic Mass Evaluation. Based on the new 27P mass, the 26Si(p, γ)27P reaction rate and its uncertainty were recalculated using Monte Carlo techniques. We also estimated the previously unknown mass excess of 27S to be 17678(77) keV, based on the measured β-delayed two-proton energy and the Coulomb displacement energy relations. The impact of these well-constrained masses and reaction rates on the modeling of the explosive astrophysical scenarios has been investigated by post-processing XRB and hydrodynamic nova models. Compared to the model calculations based on the masses and rates from databases, the abundance of A =26 in the burst ashes is increased by a factor of 2.4, while no substantial change was found in the XRB energy generation rate or the light curve. Our calculation also suggests that 27S is not a significant waiting point in the rapid proton capture process, and the change of the 26Si(p, γ)27P reaction rate is not sufficiently large to affect the conclusion previously drawn on the nova contribution to the synthesis of galactic 26Al., This work is supported by the Ministry of Science and Technology of China under the National Key R&D Programs Nos. 2018YFA0404404 and 2016YFA0400503, and the National Natural Science Foundation of China under Grants Nos. 11635015, 11805120, U1632136, 11705244, U1432246, 11775316, U1732145, 11705285, U1867212, 11805280, 11825504, 11675229, and 11490562, and the Youth Innovation Promotion Association of Chinese Academy of Sciences under Grant No. 2019406, and the Continuous Basic Scientific Research Project under Grant No. WDJC-2019-13, and the China Postdoctoral Science Foundation under Grants Nos. 2017M621442 and 2017M621035, and the Office of China Postdoctoral Council under the International Postdoctoral Exchange Fellowship Program (Talent-Dispatch Program) No. 20180068. Jordi José acknowledges funding from the Spanish MINECO grant AYA2017-86274-P, by the E.U. FEDER funds, and by the AGAUR/Generalitat de Catalunya grant SGR-661/2017.

The structures of the Ti75Al25 alloy during rapid-quenching with and without external pressure are investigated by using molecular dynamic techniques. The amorphous phase can be obtained at the cooling rate 10.0 K/ps without pressure. The alloy is composed of crystal and amorphous phase at the cooling rate 0.1 and 1.0 K/ps without pressure, but the pure amorphous phase can be formed when the pressure exceeds the critical value. The critical pressure is about 20 and 30 GPa when the cooling rate is 0.1 and 1.0 K/ps, respectively. H-A indices analysis indicates that high pressure favors the formation of the ideal icosahedral structures in the amorphous Ti75Al25 alloy, and the content of 1551 bond-type can reach near to 50% when the pressure is 30 GPa. The amorphous state can be maintained if the external pressure is removed from the alloy step-by-step. The content of 1551 bond-type decreases with the deceasing of the pressure, but the 1541 and 1431 bond-types increase in this process.

Liquid structure is still a challenging research problem. In this work, we introduce a new Atoms Loyalty Model and use it to explore the cluster structure transition in liquid states. By means of molecular dynamics simulation, this model can reveal the transient characteristics of the structure in liquid. It is helpful to understand the liquid-liquid and liquid-solid transition with the concept of cluster's stochastic volatility, which describes the process of formation of the initial cluster in liquid state. The new model can be a convenient and practical method for future studies on the liquid-glass transitions.

The effect of scratch depth on high cycle fatigue behavior of Alloy 690TT stream generator (SG) tubes was investigated by experimental characterization and numerical simulation. Results indicated that fatigue cracks initiated at the scratch root of the SG tube external surface. The effect of scratch depth on fatigue life mainly depended on the loading stress levels, which could be considered as an exponential relationship between the loading stress and scratch depth for a given fatigue life. The fatigue limit decreased with the increase of scratch depth and changed in a small range of yield strength.

The SCC crack tip of deformed Alloy 690TT tube was investigated in high temperature caustic solution. The results showed that SCC crack tip extended along the oxidation zone on the grain boundaries. The oxidation zone was composed of mixed oxides including NiO, Ni, spinel oxide and Cr2O3. Due to the competitive effect of intergranular carbides and local deformation zone (LDZ) on diffused oxygen, the oxidation zone ahead of crack tip bypassed the carbides as branched oxide and then grew up to be nodular oxidation zone, which resulted in a semi-continuous nodular pattern for the oxidation zone along the crack.

The effects of uniformly distributed spherical B2-CuZr crystal particles on the mechanical properties of Cu50Zr50 amorphous alloy were studied. With the increasing of the radius of B2-CuZr particles, the yield strength of nanocomposites decreases first and then increases. In this study, the material shows the best comprehensive mechanical properties when the radius of B2-CuZr particle is 2.3 nm, corresponding volume fraction is 29.1%. Compared with the Cu50Zr50 amorphous alloy, multiple shear bands were formed in the Cu50Zr50 amorphous/B2 crystalline composites during compression. Analysis of the deformation mechanism show that the amorphous-crystalline interfaces play the key role in this process. B2-CuZr particles retard the rapid expansion and propagation of the single shear band, and it makes the nanocomposites have the better plasticity than the Cu50Zr50 amorphous alloy.

Ceratovacuna lanigera Zehntner is a major leaf pest of sugarcane. Widely distributed, it affects both the yield and quality of sugarcane in China. This study aimed to assess real yield and sugar yield losses, and the effect of C. lanigera damage on emergence of newly planted and ratoon cane under current production levels. Field experiments were carried out from 2014 to 2016 in Yunnan Province China. At maturity, plants were harvested and weighed to determine yield, and the effect on sugarcane quality and sucrose content analyzed. Real yield decreased by average of 46,185 kg hm−2 (range: 37,545–61,845 kg hm−2) in damaged versus undamaged areas, with an average yield loss rate of 35.9% (28.5–45.7%). Juice yield decreased by an average of 3.01% (2.4–4.13%) and sucrose content by 6.38% (5.48–8.16%). Juice brix decreased by an average of 7.66°BX (6.95–9.05°BX) and juice gravity purity by 12.35% (8.43–19.97%). In contrast, the reducing sugar content increased by an average of 1.21% (1.01–1.3%). Emergence rates of newly planted cane decreased by an average of 26.0% (24.7–27.3%). The emergence number of ratoon cane decreased by 66,834 hm2 (57,429–76,238 hm−2) and relative emergence loss rates of ratoon cane decreased by an average of 57.8% (57.6–58.0%). These findings confirm that C. lanigera damage severely affects sugarcane yield and quality in Yunnan Province. The results will help the implementation of effective control measures, thereby supporting sustainable development of the Chinese sugar industry.

An 8-week feeding trial was conducted to estimate the optimum dietary manganese (Mn) requirement for juvenile hybrid grouper, Epinephelus lanceolatus × E. fuscoguttatus. The basal diet was formulated to contain 520 g/kg crude protein from casein and fishmeal. Manganese methionine was added to the basal diet at 0 (control group), 2.5, 5, 10, 20 and 40 mg Mn/kg diet providing 7.48, 10.34, 13.76, 19.72, 31.00 and 53.91 mg Mn/kg diet, respectively. Each diet was randomly fed to triplicate groups of juveniles, and each tank was stocked with 20 fish (initial weight, 60.06 ± 0.68 g). The manganese content in rearing water was monitored and kept below 0.01 mg/L. Results showed that the weight gain ratio (WGR), protein efficiency ratio (PER), specific growth rate (SGR), Mn contents in whole body, liver and vertebra, and activities of hepatic Mn superoxide dismutase (Mn-SOD), total SOD (T-SOD) and glutathione peroxidase (GSH-PX) were significantly improved by dietary Mn supplementation (p