Search

Aims: Plant S concentration (Sc) and nitrogen (N) to S ratio (N:S) in canola are important indicators for diagnosing S deficiency. A field study was conducted on sandy and clay loam soils at two sites in eastern Canada for three growing seasons to determine plant critical Sc and N:S ratios across various growth stages (GSs). Methods: For each site year, factorial experiments consisting of combinations of four N levels (0, 80, 160, and 240 kg N ha–1) as urea (46–0–0) and four S levels (0, 20, 30, and 40 kg S ha–1) as potassium sulfate (0–0–50–18) were classified orthogonally to form 16 combinations. Muriate of potash (0–0–60) was also applied as needed to ensure all plots receiving the equal amount of potassium (K). Results: Our study found that S fertilization increased plant Sc at each GS but reduced the whole‐plant N:S ratio, and the effect was stronger during the flowering stage. Both whole‐plant Sc and N:S ratios varied with GS, environment, and soil type and declined with plant aging. Our results showed that whole‐plant S analysis combined with visual signs of plant S deficiency (purple‐edged and cup‐shaped leaves with less green; stunted growth, slow blooming, and fewer flowers) appeared to be the best way to identify S problems in the field, and whole‐plant Sc and N:S ratios could confirm S deficiencies. Conclusion: Our findings indicated that if the whole‐plant Sc in the rosette stage is <0.35% and the N:S ratio is >9.6, the plant may be S‐deficient, and timely supplementary S fertilization measures may be beneficial to canola crop yield. [ABSTRACT FROM AUTHOR]

Background and aim: Deep roots are important for crops to access water when the topsoil is dry. Root anatomy and activity play an important role in water uptake. However, little is known about the effects of root distribution and anatomical structure on water uptake and grain yield under different water conditions. This study aimed to reveal the contribution of deeper roots, root anatomy and root activity on grain yield and water use efficiency. Methods: A field experiment and Rhizobox experiment were performed to evaluate the effects of changes in root distribution, root anatomy and root activity on grain yield and water use efficiency under three water conditions. Three dryland wheat cultivars (BM1, CH58 and CH1) were compared. Results: BM1 formed a root system, which limited the acquisition of water in the subsoil, resulting in lower grain yield and water use efficiency in field and rhizobox experiments. In contrast, cultivars CH58 and CH1 exhibited greater root biomass and root length density in the subsoil, optimizing subsoil water uptake, thereby increasing grain yield and water use efficiency. CH58 had a smaller root diameter and vessel diameter, thicker cortex thickness, higher root cortex thickness-to-diameter ratio and higher root activity. Conclusion: This study demonstrated that, deeper roots, root anatomy and root activity are important traits in selecting wheat cultivars that maintain yield under low water conditions. Therefore, wheat crop development and breeding to improve grain yield should also consider optimizing root anatomy and improving root activity while promoting deep root development. [ABSTRACT FROM AUTHOR]

Nitrogen (N) is an essential nutrient for plant healthy growth and development, determining crop performance and yield outcomes. However, less than 50% of the N fertilizer applied in modern agricultural systems is effectively utilized by crops in the year of planting, causing resource waste and environmental harm. To improve N use efficiency (NUE), it is crucial to prioritize root performance as it primarily controls the plants' ability to absorb and utilize soil nutrients. The robustness of the root system is also closely related to crop lodging, which is an important factor that hinders the absorption, assimilation, translocation and distribution of N in major field crops. This review attempts to comprehensively summarize recent advances in plant root biology in the context of climate change, emphasizing its important role in soil nutrient dynamics and crop lodging risk, as well as its comprehensive impact on NUE of field grain crops. We discussed the importance of balanced and precision nutrient management to improve NUE and highlighted the innovative role of machine learning in modern agriculture, including root phenotyping, crop lodging detection and nutrient management decisions. Overall, combining machine learning with root biology, along with other practices such as crop rotation, cover cropping, use of biostimulants, and balanced nutrient supply, can reduce lodging risk and promote N uptake and utilization, thereby simultaneously improving NUE, crop productivity and agroecosystem sustainability. This helps ultimately secure our food supply while minimizing the negative impact of N on the environment facing unprecedent climate change. [ABSTRACT FROM AUTHOR]

Crack identification is essential for the preventive maintenance of asphalt pavement. Through periodic inspection, the characteristics of existing and emerging cracks can be obtained, and the pavement condition index can be calculated to assess pavement health. The most common method to estimate the area of cracks in an image is to count the number of grid cells or boxes that cover the cracks in an image. Accurate and efficient crack identification is the premise of crack assessment. However, the current patch‐based classification method is limited by the receptive field and cannot be used to directly classify cracks. Furthermore, the postprocessing algorithm in anchor‐based detection is not explicitly optimized for crack topology. In this paper, a new model, which is the fusion of grid‐based classification and box‐based detection based on You Only Look Once version 5 (YOLO v5) is developed and described for the first time. The accuracy and efficiency of the model are high partly due to the implementation of a shared backbone network, multi‐task learning, and joint training. The non‐maximum suppression (NMS)–area‐reduction suppression (ARS) algorithm is presented to filter redundant, overlapping prediction boxes in the postprocessing stage for the crack topology, and the mapping and matching algorithm is proposed to combine the advantages of both the grid‐based and box‐based models. A double‐labeled dataset containing tens of thousands of asphalt pavement images is assembled, and the proposed method is verified on the test set. The fusion model has superior performance over the individual classification and detection models, and the proposed NMS‐ARS algorithm further improves the detection accuracy. Experimental results demonstrate that the presented method effectively realizes automatic crack identification for asphalt pavement. [ABSTRACT FROM AUTHOR]

Given the worldwide effort to improve crop drought resistance, it is crucial to understand the mechanisms of root system adaptation of ploidy wheat to water‐deficient environments. A meta‐analysis was performed to examine the changes in root system mechanisms under drought conditions. Data used in the analysis were drawn from 192 papers, taking into account wheat ploidy levels as well as pot and field studies. The results illustrated that water stress reduced grain yield and aboveground biomass to a greater extent in diploid and tetraploid compared with hexaploid genotypes. In contrast, drought reduced root biomass, root surface area and root volume more in hexaploid than in diploid and tetraploid wheat. Under water‐limited conditions, diploid and tetraploid genotypes exhibited greater root biomass and root length densities in the topsoil. Hexaploid genotypes greatly reduced root biomass and root length density in the topsoil and maintained higher root biomass and root length density in subsoil. These genotypes also showed smaller root diameter and xylem centre vessel diameter under drought conditions. The analysis revealed that grain yield was negatively correlated with topsoil root biomass and root length density, root volume, root diameter and xylem centre vessel, but positively correlated with subsoil root mass, root length density and root vigour. The study demonstrated that domestication and selection pressures of ploidy wheat have altered wheat root system traits while improving grain yield. Greater root mass and root length densities in the subsoil facilitate access to soil moisture from deep layers, contributing to high yields in drought environments. [ABSTRACT FROM AUTHOR]

BACKGROUND: Most plant breeding and agricultural practices are based on selecting genotypes for yield. However, this is inadequate to screen crop varieties for specific attributes, such as drought tolerance. In this study, we quantified the response of oat (Avena sativa L.) plant physiological and morphological traits to drought stress and selected some key traits to establish a genotype by yield*trait (GYT)‐based method for ranking 30 oat genotypes. The effectiveness of this method was also evaluated under drought conditions. RESULTS: Water‐deficit treatment significantly reduced leaf chlorophyll, root morphological traits, groat yield and associated components, such as mean grain weight. We observed that the genotypes 'JUSTICE' and 'BOLINA' had the smallest and largest yield loss, respectively, after exposure to drought stress, but showed opposite trends in the biomass allocation of roots and grains. This indicated that drought tolerance was highly dependent on the distribution of photoassimilates. Our results also illustrated that the GYT method is a trade‐off approach and more effective in selecting oat ideotypes under drought conditions than the yield‐related index method because it combines yield, yield stability, and related agronomic traits in the calculation process. CONCLUSION: Drought‐tolerant genotypes had more biomass allocated to roots and grains with higher chlorophyll content and better root structure, e.g. longer root lengths than drought‐sensitive lines. By integrating yield and yield‐related traits, the GYT approach is more practical than traditional single‐trait selection methods when assessing drought tolerance. © 2023 His Majesty the King in Right of Canada. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. Reproduced with the permission of the Minister of Agriculture and Agri‐Food Canada. [ABSTRACT FROM AUTHOR]

High biomass and nutrient acquisition are desirable for oat (Avena sativa L.) as a cover crop. However, our understanding of oat genotypes suitable for cover crops and associated traits is limited. The objectives of this experiment on growing oat as a cover crop, after winter wheat (Triticum aestivum L.) harvest, were to determine biomass production, nutrient uptake of a set of oat genotypes, and to identify phenotypic traits that can be used as indicators to select cultivars suitable for cover crops. The results showed that the top biomass-producing genotypes took up larger amounts of soil nutrients, up to 142 kg N ha−1 and 17 kg P ha−1 in 2016, and 43.5 kg N ha−1 and 8.3 kg P ha−1 in 2017. The biomass production was significantly related to plant height and leaf area index (LAI) in both years, and to the normalized difference vegetation index (NDVI) in 2017. Both NDVI and LAI were closely related to the total amounts of N and P uptake. The poor association between biomass and NDVI in 2016 was due to vigorous growth of volunteer wheat and weeds as well as severe rust (Puccinia coronata f. sp. avenae Eriks.) infestation. Our results suggest that it is important to choose oat varieties as cover crops. Leaf area index can be used as a nondestructive indicator for final biomass and nutrient acquisition, while both NDVI and LAI are important traits for choosing oats as soil conservation cover crops. [ABSTRACT FROM AUTHOR]

Animal manure is an excellent renewable source of plant nutrients, but the correct quantification of nutrient equivalents is affected by manure type and application rate as well as weather conditions that impact crop yields The objectives from a 32-year field experiment were to (1) compare the effects of mineral N fertilization and solid dairy cattle manure on corn grain yield; (2) determine the manure N fertilizer replacement value (NFRV), and (3) quantify environmental factors, mainly the impact of total precipitation during the critical period (silking) on corn yield and manure NFRV. A field experiment under continuous corn with annual manure application was conducted over 32 years in Ottawa, Ontario, Canada. Corn yield data were categorized into low, intermediate, and high N response groups. On an equivalent amount of manure organic N basis, NFRVs were, on average, 0.38 (±0.02) for stockpiled manure (SM) and 0.27 (±0.02) for incompletely composted or rotted manure (RM), with a wide range of 0.12 (±0.02), 0.28 (±0.02), and 0.37 (±0.04) for RM, and 0.16 (±0.04), 0.39 (±0.03), and 0.48 (±0.04) for SM under the low, intermediate, and high N response conditions, respectively. Supplementing 100 kg synthetic fertilizer N ha−1 in low RM (50 Mg ha−1 fresh weight; f.w.), and 50 kg fertilizer N ha−1 in high RM (100 Mg ha−1 f.w.) application rates decreased NFRVs under low and intermediate N response conditions, whereas the addition of similar synthetic N in the corresponding SM rates reduced NFRVs only under low N response conditions. Based on the 32-year long-term study, we documented that the maximum economic synthetic N fertilizer rates for continuous corn cropping varied from 117 to 179 kg N ha−1 under the low N response, from 127 to 283 kg N ha−1 under the intermediate N response, and from 227 to 289 kg N ha−1 under the high N response conditions. The NFRVs of solid cattle manures varied according to corn yield-N response levels. Our findings showed that the response of corn yields to manure NFRV depends on the level of yield-N response and climatic conditions. It also indicated the importance of soil organic amendments for improving the climate resilience of corn production, while simultaneously meeting the demand for more sustainable nutrient management of soil resources. • Corn grain yield responded quadratically to rates of synthetic N fertilizer. • Yield and N response curves can be grouped into low, intermediate, and high levels. • Nitrogen fertilizer replacement value (NFRV) of solid manure depends on yield-N response patterns. • NFRV varies with manure type, application rate, and whether synthetic N fertilizer is supplemented. [ABSTRACT FROM AUTHOR]

Crop avoidance and tolerance strategies are critical adaptive mechanisms of drought stress and play different roles in grain yield. However, little is known about the contribution of these two mechanisms to grain yield in old and modern wheat genotypes. Here, pot and field experiments were carried out to characterize and compare the mechanisms of drought avoidance and drought tolerance, and determine their differential contributions to the yield in six wheat genotypes. The pot experiment results demonstrated that the old genotypes acquired a better avoidance ability to adapt to drought stress. These avoidance abilities include larger root systems, lower leaf areas, low stomatal conductance, pale green leaf colour, higher degrees of leaf rolling and leaf waxiness. The modern genotypes displayed stronger drought tolerance advantages, such as high osmotic adjustment and antioxidant enzyme activity, and a smaller root system. Our field experiment further showed that under severe water-deficit conditions, the old genotypes with stronger drought avoidance traits had higher yields and water use efficiency (WUEg), whereas the modern genotypes with strong drought tolerance characteristics produced higher yields and had higher WUEg under mild and intermediate water deficits. The results indicate that the relative contribution of drought tolerance and drought avoidance to grain yield depends to a large extent on the degree of drought stress and genotypes. Understanding the differential plant response depending on genotype and drought stress may help plant breeders develop drought-resistant varieties suitable for drought-prone environments under anticipated climate change scenarios. [ABSTRACT FROM AUTHOR]

BACKGROUND Modern wheat cultivars have been developed having distinct advantages in many aspects under drought stress, such as plasticity in biomass allocation and root system architecture. A better understanding of the biomass allocation mechanisms that enable modern wheat to achieve higher yields and yield‐based water use efficiency (WUEg) is essential for implementing best management strategies and identifying phenotypic traits for cultivar improvement. We systematically investigated the biomass allocation, morphological and physiological characteristics of three ploidy wheat genotypes under 80% and 50% field water‐holding capacity (FC) conditions. Some crucial traits were also assessed in a complementary field experiment. RESULTS: The diploid and tetraploid genotypes were found to allocate more biomass to the root system, especially roots in the topsoil under drought stress. Our data illustrated that lower WUEg and yield of these old genotypes were due to excessive investment in the root system, which was associated with severely restricted canopy development. Modern hexaploid genotypes were found to allocate smaller biomass to roots and larger biomass to shoots. This not only ensured the necessary water uptake, but also allowed the plant to distribute more assimilates and limited water to the shoots. Therefore, the hexaploid genotypes have evolved a stable plant canopy structure to optimize WUEg and grain yield. CONCLUSION: This study demonstrated that the biomass shift from below ground to above ground or a more balanced root:shoot ratio tended to optimize water use and yield of the modern cultivars. This discovery provides potential guidance for future dryland wheat breeding and sustainable management strategies. © 2021 Her Majesty the Queen in Right of Canada Journal of The Science of Food and Agriculture © 2021 Society of Chemical Industry. Reproduced with the permission of the Minister of Agriculture and Agri‐Food Canada. [ABSTRACT FROM AUTHOR]

While no significant differences in initial ovule number were found among oilseed rape Brassica napus genotypes, there was a large variation in effective ovule number (EON), which determines the final seeds per silique (SPS), a critical component of yield. In this study, we selected 18 oilseed rape Brassica napus genotypes with contrasting nitrogen utilization efficiency (NUtE) to unravel the main factors responsible for different EON and determine the critical period of EON formation under both a field and a pot experiments from 2016–2018. The high NUtE genotypes displayed significantly higher NUtE by 14.3%, along with greater yield per plant (29.4%) and SPS (21.1%) than the low NUtE genotypes. The greater productivity of the high NUtE genotypes was associated with 44.1% higher pollen grain number, 23.5% greater pollen viability, and 39.3% lower ovule abortion rate, compared to the low NUtE genotypes. In addition, the heart stage was the critical ovule development period for delineating the variability of EON among contrasting NUtE oilseed rape Brassica napus genotypes, when the high NUtE genotypes displayed higher silique net photosynthetic rate, surface area, biomass, and RNA expression levels. Taken together, this study indicated the pollen grain number, pollen viability and ovule abortion rate contributed to the final variation in EON and the heart stage was the critical period of determining the EON differences among contrasting NUtE genotypes. Increasing pollen grain number and pollen viability, and decreasing ovule abortion rate before heart stage should be the prerequisite for breeders to improve yield and NUtE of oilseed rape Brassica napus genotypes. [ABSTRACT FROM AUTHOR]

Preliminary studies observed a lower growth activity during the vegetative stage with higher growth attributes at the pod-filling stage among the high nitrogen (N) utilisation efficiency (NUtE) oilseed rape (Brassica napus L.) genotypes, compared with the low NUtE genotypes. Therefore, we hypothesised that there would exist a critical growth stage when distinctive phenotypic traits are exhibited to regulate yield formation and NUE. A field experiment and a hydroponic culture were conducted to characterise the differences in shoot and root physiological indicators of the high and low NUtE oilseed rape genotypes at seedling, bud, bolting, flowering and pod-filling stages. We found that flowering was the critical period when the reverse growth habit occurred between high and low NUtE genotypes. The high NUtE genotypes displayed larger values of root traits, stronger N uptake kinetics parameters, higher activity of leaf glutamine synthetase (GS) and glutamate synthetase (GOGAT), larger SPAD values and net photosynthetic rate, ultimately leading to higher seed yield and NUE. Our results indicate that flowering is the critical growth stage to distinguish the high from low NUtE oilseed rape genotypes, and plant breeders may focus on selecting root and shoot phenotypic traits from flowering stage onwards to achieve both high yields and NUE for oilseed rape genotypes. [ABSTRACT FROM AUTHOR]

Stem lodging is a common problem in cereal crop production and a main constraint for grain yield improvement. The leaf sheath that surrounds and protects the hollow internodes of stem could provide the plants with a great physical support. However, this biomechanical function has been ignored for several decades in cereal crops. This study aimed to examine the biomechanical properties of basal stem internodes and lodging susceptibility of the whole plants with or without the clasping leaf sheath in wheat (Triticum aestivum L.) and oat (Avena sativa L.) among different genotypes and agronomic practices (including planting densities and nitrogen application rates). The main objective was to quantify the mechanical role of the leaf sheath in oat and wheat crops by a "safety factor" method. On average, the leaf sheath contributed 40%, 68% and 38% of the overall stem bending strength, flexural rigidity and safety factor, in oat, while it accounted for 11%, 24% and 10%, respectively, in wheat plants. The significant contribution of the leaf sheath is due to its vital role in enlarging the peripheral position (i.e., second moment of area) and stiffness (i.e., Young's modulus). The contribution ratios (%) were found to be higher in oat than in wheat plants, due to the greater mass density of leaf sheath and more proficient/prevailing stay‐green capability in oat genotypes. This study emphasizes the important mechanical role of clasping leaf sheath on stem internodes of cereals and indicates that the stay‐green trait of the leaf sheath can be exploited to design appropriate varieties with improved lodging resistance and great yield potential. [ABSTRACT FROM AUTHOR]

Balanced plant nutrition is essential to achieve high yields of canola (Brassica napus L.) and get the best economic return from applied fertilizers. A field study was conducted at nine site‐years across eastern Canada to investigate the effects of nitrogen (N), sulfur (S) and boron (B) fertilization on canola nutrient uptake, nutrient balance, and their relationship to canola yields. The factorial experiment consisted of four N rates of 0 (N0), 50 (N50), 100 (N100), and 150 (N150) kg ha−1, two S rates of 0 (S0) and 20 (S20) kg ha−1, and three B treatments of 0 (B0), 2 kg ha−1 at preplant (B2.0P), and 0.5 kg B ha−1 foliar‐applied at early flowering stage (B0.5F). Each site‐year used the same experimental design and assigned treatments in a randomized complete block design with four replications. Fertilizer S application greatly improved seed yields at six out of nine site‐years, and the highest N use efficiency was in the N150+S20 treatment. Sulfur application generally increased seed S concentration, seed S removal, and plant total S uptake, while B fertilization mainly elevated straw B concentration and content, with minimal effect on seed yields. At the early flowering stage, plant tissue S ranged from 2.2 to 6.6 mg S g−1, but the N : S ratio was over or close to the critical value of 12 in the N150+S0 combination at five site‐years. On average across nine site‐years, canola reached a plateau yield of 3580 kg ha−1 when plants contained 197 kg N ha−1, 33 kg S ha−1 and 200 g B ha−1, with a seed B content of 60 g B ha−1. The critical N, S, and B values identified in this work and their potential for a posteriori nutrient diagnosis of canola should be useful to validate fertilizer requirements for canola production in eastern Canada. [ABSTRACT FROM AUTHOR]

Highlights • Erect leaf posture improves resistance of oat plants to lodging. • Prostrate leaf stature reduces oat resistance to lodging under dense planting. • Oat plants are more prone to anchorage failure than stem buckling. • Important plant ideotype traits are identified to improve oat yield and lodging resistance. Abstract Developing an appropriate strategy to increase oat yield potential to meet the increasing market demand and overall returns is urgently needed. Crop lodging is the main constraint for improving oat yields. The objectives of this study were aimed to evaluate the effect of leaf posture on crop lodging resistance and lodging related traits, yield performance and their responses to plant populations. Four genotypes with similar yield potential, but differing substantially in leaf architecture, i.e., erect–leaf (E) vs. prostrate–leaf type (P), were tested under three plant population conditions. The results showed that with increasing plant densities from 200 to 600 plants m–2, resistance to stem lodging, resistance to root lodging, and grain yield were decreased, respectively by 21.9%, 14.9% and 6.8% for the P cultivars, but increased by 11.5%, 28.7%, and 3.2%, for E cultivars, averaged across both years. It implied that erect–leaf posture could promote crop resistance to lodging, especially under high plant population condition. Oat plants were more prone to anchorage failure than stem buckling, which was illustrated by the quantitative "safety factor" that was closely related to the visual lodging scores based on field investigation (R2 = 0.56* in 2017). Thus, root lodging should be targeted as the priority criteria in oat breeding for selecting more rigid root system. Taken together, two important attributes of the plant ideotype, i.e., erect–leaf architecture and rigid root system, could be recommended to plant breeders in selecting oat cultivars with improved high–yielding potential and strong lodging resistance. [ABSTRACT FROM AUTHOR]

Abstract First-principles calculations were performed to investigate the structural, elastic, electronic and sensitive properties of triclinic TATB crystal. The obtained ground state properties using GGA-PBE method were in agreement with the previous theoretical and experimental data. The elastic constants, bulk modulus, shear modulus, Young's modulus, Poisson's ratio, anisotropy under the hydrostatic pressure from 0 GPa to 30 GPa were calculated and analyzed. Moreover, we found that TATB became more and more hardness with the increasing pressure. Furthermore, comparing the density of states in different pressures, we can find that the electrons of TATB become more active under ambient pressure. Highlights • The elastic constants, bulk and shear modulus, Young's modulus, Poisson's ratio, anisotropy under 0 to 30 GPa were analyzed. • TATB became more and more hardness with the increasing pressure. • Starting from 2 GPa, TATB has changed from brittleness to ductility. • The band structures and density of states of TATB were associated with sensitivity. [ABSTRACT FROM AUTHOR]

The inspection of bridges is increasingly dependent on advanced equipment and algorithms like digital cameras and SfM (Structure from Motion). However, many existing SfM-based bridge inspection methods lack efficiency due to lengthy 3D reconstruction computation times, and digital image resolution often falls short in detecting fine cracks and calculating their widths, mainly influenced by the acquisition equipment. This paper describes a fast and accurate crack assessment method that leverages multi-sensor fusion SLAM (Simultaneous Localization and Mapping) and image super-resolution. Through multi-sensor fusion SLAM, textured point clouds of the bridge structure can be obtained directly, significantly improving efficiency. Furthermore, deep learning-based image super-resolution enhances the precision of crack width calculation. Field tests demonstrate the effectiveness of the proposed methods, showcasing a 94% reduction in scene reconstruction time and a 16% improvement in crack width calculation accuracy. • Multi-sensor fusion SLAM is applied in bridge inspection for the first time which greatly improves the inspection efficiency. • A deep learning-based crack image super-resolution model is trained to enhance the accuracy of width calculation. • The performance of both SLAM and SfM methods for scene reconstruction are meticulously compared. • A quantitative study is conducted to assess the impact of image super-resolution on the accuracy of crack width calculation. [ABSTRACT FROM AUTHOR]

Hybrids are currently the dominant varieties in canola production, but their yield response to nitrogen (N) application across Canada has not been adequately updated. As a result, there is a lack of effective N management guidelines for modern hybrid canola to reach their full yield potential and cope with growing abiotic stresses caused by climate change. This study was designed to investigate the responses of yield and N use efficiency (NUE) of modern canola hybrids to N fertilization for determining site-specific economic optimum N rates (EONR). Additionally, the key driving factors of canola yields and N recommendations were identified. A 32 site-year field study across Canada was conducted to test 8 combinations of N rates and application methods on 2 site-specific hybrids in each trial. Nitrogen fertilization greatly increased canola yield by an average of 41%, with significant responses in 19 out of 32 trials. Split-N strategy led to similar yield, NUE, and yield response index compared to preplant-only N application. However, these traits varied among hybrids due to different growing environments and hybrid-specific tolerance to abiotic stresses. The number of heat-stress days and heat-induced thermal accumulation surrounding the 4 weeks before and post-flowering stage directly determined the canola responses to N fertilization and EONR. Our results suggest a site-specific EONR of 146–166 kg N ha−1 in the Black soil zone, 85–100 kg N ha−1 in the low-yielding Brown soil zone, and 140 kg N ha−1 in Ontario, preferably with a split-N strategy for hybrid canola production. The split-N fertilization is generally recommended, as it provides an opportunity to adjust the amount of topdressing N based on historical and early season weather conditions to achieve the dual goals of increasing canola productivity and reducing greenhouse gas (GHG) emissions from fertilizer use. The energy and time costs must be considered when making practical decisions. Environment-specific selection of canola hybrids also played an important role in the response to N, with '6074RR' in favorable weather and 'L233P' in drought-prone conditions appearing to be good choices for specific ecoregions. • Up to 200 kg N ha−1 increased canola yield by an average of 41%, but decreased NUE by 53%. • Benefit of split- vs. preplant-N fertilization in improving yield and NUE depends on rainfall patterns. • Yield response and EONR were mainly affected by heat-stress days in the 4-week flowering period. • In Canada, zone-specific EONRs of canola varied from 85 to 165 kg N ha−1. [ABSTRACT FROM AUTHOR]

Globally, the increase in climatic variability is responsible for more frequent extreme heat and drought stress events. Heat and water stress have a devastating impact on plant growth, development, and formation of the yield components of rapeseed/canola, an important oilseed crop for human consumption and a renewable feedstock for biodiesel production. The growing demand for rapeseed/canola will not be met unless strategies are rapidly developed to sustain and improve crop yields and product quality in the context of global climate change. Therefore, the objective of this review is to discuss the development of rapeseed/canola varieties with enhanced tolerance to heat and drought stresses, as the most promising solution to improve crop productivity in the future. The genetic basis of stress tolerance has provided plant breeders with new options for efficient breeding programs that support high yield potentials under both favorable and stressful environments. This review provides an update on recent advances in characterizing the response of rapeseed/canola to heat and drought stresses, from the molecular level (i.e., signal transduction) to phenotypes at the whole-plant and agroecosystem scales. Of particular interest is the ability of the root system to alleviate abiotic stressors. Roots, as the "hidden half" of the plant, play a central role in acquiring water and nutrients (i.e., improving water and nutrient use efficiencies) as well as anchoring the crop so it can resist lodging and tolerate heat and drought stresses. Considering the urgent need to achieve sustainable production of rapeseed/canola under changing climatic conditions, it is essential to determine how the root system can mitigate abiotic stress. Modern methodologies to quantify root system architecture are presented. Finally, we describe root-specific tolerance mechanisms to abiotic stress and explain how this information can be used to direct breeding programs and decide on agronomic practices that support sustainable rapeseed/canola production now and under future climate change scenarios. [ABSTRACT FROM AUTHOR]

We have used the first-principles density-functional theory calculations to study the structural parameters, Raman/IR spectrum, electronic, vibrational, dielectric, thermodynamic and optical properties of TATB. The obtained structural parameters and the vibrational frequencies of the internal modes are consistent with previous results. The results of density of states, bond populations and Mulliken charges are used to analyze the electronic properties and chemical bondings. The vibrational frequencies (in 300–3267 cm −1 ) are assigned to corresponding vibrational modes. We also used the phonon density of states and quasiharmonic approximation to calculate entropy, enthalpy, heat capacity and Gibbs free energy. Further, the permittivity, refractive index, reflectivity, absorption coefficient, loss function and optical conductivity have been obtained. [ABSTRACT FROM AUTHOR]

With temperatures rising due to global climate change, many endeavors have been looking into how this will affect crop production and food security. Lodging, which is the permanent displacement of crop plants from upright position, is one of the main causes of yield loss and quality reduction in canola/oilseed rape. However, there has been little research to date on how the mechanisms of crop lodging might be affected by high temperature. The objectives of this study were to examine the effect of high temperature on the structural features of lodging resistance in four canola genotypes, to determine what kind of lodging (stem or root) was more prevalent, and to identify corresponding mechanistic traits associated with lodging under high temperature conditions. The experiment was carried out in controlled growth facilities with the genotypes tested under normal (23/17 °C; CK) and high temperature (27.01/24.3 °C) regimes. The results showed that high temperature reduced root lodging resistance significantly, as indicated by a dramatic reduction in both root anchorage and safety factor (against anchorage failure). These were attributable to the large suppression on lateral root growth (32%), and thereby reduction in root bending resistance (33%), root–soil cone dimension (13%), and its shear strength (33%). High temperature showed an inconsistent effect on stem lodging resistance, which was in alignment with the engineering mechanics theory and supported by the anatomical observations. These results indicated that canola genotypes were more prone to anchorage failure than stem buckling. Consequently, root lodging resulted from anchorage failure would become a critical aspect under rising temperatures with the global warming. The present study indicates that root lodging should be targeted as a priority to improve crop lodging resistance through breeding selection for a root system with high anchorage strength, especially when the crop plants are expected to encounter inevitable high temperature stress. [ABSTRACT FROM AUTHOR]

BACKGROUND The eco-physiological mechanism of wheat yield loss resulting from chilling stress is a fundamental scientific issue. However, previous studies have focused on hexaploid wheats, and few studies on the morphological and physiological plasticity of wheat plants. Six different wheat genotypes were tested under chilling stress to investigate the physio-morphological parameters as well as the loss of grain yield in growth chambers. RESULTS Chilling stress resulted in significant loss in grain yield in all genotypes. Under chilling stress, diploid wheats generated zero harvest, and tetraploid genotypes also suffered from a pronounced loss in grain yield, compared with the control group. In contrast, hexaploid genotypes acquired relatively high maintenance rate of grain yield among three species. CONCLUSIONS Diploid and tetraploid wheat genotypes maintained relatively large leaf area and high photosynthetic rates, but they were subjected to significant declines in vascular bundle number and productive tillers as a consequence of the inhibition by sink growth under chilling stress. The hexaploid wheats were found to have relatively low leaf area and photosynthetic rates. These genotypes also stored more soluble carbohydrates and exhibited stronger sink enhancement, ensuring the translocation and redistribution of assimilates. Our findings provided a new theoretical understanding of yield stabilization in the domestication process of wheat genotypes under chilling stress. © 2017 Her Majesty the Queen in Right of Canada. Journal of The Science of Food and Agriculture © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND The hypothesis that positive and negative interactions account for adaptive strategies was tested in a controlled study with two oat ( Avena sativa) genotypes: 'Manotick' with erect leaves and 'Oa1316-1' with prostrate leaves. An increasing competition pattern was designed by varying the number of seeds planted in each container and the space between containers, thus creating different planting density regimes (i.e. alternative and solid treatments). RESULTS Total biomass of individual plants tended to decrease exponentially with increasing density in both genotypes. Under high density stress, Manotick allocated more biomass to the roots and produced 50% more tillers, leading to more non-productive tillers and lower harvest index in the alternative than in the solid treatment. In contrast, Oa1316-1 allocated more biomass to panicles and stems, and less to the roots, with fewer tillers. CONCLUSIONS With increasing density and strengthening intraspecific competition, Manotick reduced aboveground biomass allocation, leading to lower yield, while Oa1316-1 decreased allocation to the roots, but increased allocation to the panicles under an increasingly competitive environment. These adjustments were mechanically derived from negative and positive interactions, ensuring greater yield in the prostrate type. Our findings provided a novel rationale for a planting strategy based on plant type selections. © 2015 Her Majesty the Queen in Right of Canada. Journal of the Science of Food and Agriculture © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Machine learning approaches are attracting more attention in predicting the economic optimum nitrogen rate (EONR) for field crop production. However, the robustness in fertilizer recommendations appeared to be less responsive to extreme abiotic stress conditions, due to the lack of post-fertilization seasonal weather information. This study employed four machine learning models, namely, support vector machine (SVM), gradient boosting (GB), random forest (RF), and ridge regression (RR) to predict the site-specific EONR values of canola crops, based on a 22-site-year field study across eastern Canada. Model performance was assessed using the 'leave-one-out' approach under three scenarios, i.e., different combinations of input variables, including current seasonal weather data before N topdressing, 10-year historical weather records, and field management and crop traits. Results of this study showed that including historical weather data highly improved prediction accuracy for EONR in a variety of canola growing environments. The RF model outperformed other models in predicting site-specific EONRs, with a Pearson correlation coefficient of 0.9, a standard deviation of 23 kg N ha−1 and a relative error of 2%. For 16 of the 22 test environments, the EONR predicted using RF fell within its confidence range, indicating that the prediction has a 73% chance of being an acceptable recommendation. Overall, incorporating historical weather data is essential for successfully predicting crop N requirements under normal and stressful growing conditions. The results indicate that with a base fertilizer of 50 kg N ha−1, the recommended topdressing application rate varied from 50 to 110 kg N ha−1 in moist seasons, but decreased to 20–50 kg N ha−1 in hot and dry years, for sustainable canola production in eastern Canada. Appropriately incorporating historical weather data and soil properties into machine learning-based algorithms can be used to precisely guide fertilizer N management on canola crops under diverse climatic stress conditions. This approach promises to optimize seed yield and reduce nitrogen losses to the environment for sustainable canola production in Canada. • Four machine learning models were compared to predict economic optimum nitrogen rate (EONR). • Historical weather conditions were essential to predict the site-specific EONR. • Random forest model performed the best in recommending EONR by integrating weather data, field management and crop features. • A rate of 50 kg N ha−1 at planting plus 20–110 kg N ha−1 at the 4–6 leaf stage is recommended for canola production. [ABSTRACT FROM AUTHOR]

Efficient nitrogen (N) nutrient management is important for developing sustainable strategies to increase seed yield while reducing negative environmental impacts. Motivation to increase seed yield by appropriately increasing N application rates would make crop lodging a potential problem. Fewer studies have been conducted to elucidate the trade–off between yield gain and lodging susceptibility in canola (Brassica napus L.), and a non–destructive and high–throughput assessment of lodging is seriously lacking. In this regard, a field study consisting of two varieties and five combinations of rates and timing of N application was conducted to explore the strength of their trade–offs for better N fertilization recommendation and to determine the feasibility of non–destructive technique for diagnosing canola lodging susceptibility. Two non–destructive techniques including root electrical capacitance and normalized difference vegetative index (NDVI) were verified in this study. The susceptibility of stem and root lodging were quantified by "safety factor" method. The results showed that there was a trade–off between seed yield and lodging resistance under conditions of seed yield greater than 1.3 t ha–1. Under high–yielding condition of 2021 cropping season, split–N treatment, 50 kg N ha–1 at preplant plus 50 kg N ha–1 topdressed at the 6–leaf stage, increased seed yield by 20% and lodging resistance by 38% for hybrid 'Invigor L233P', compared with the equivalent preplant–only N application. However, under low–yielding condition, split–N treatments did not always show advantages over the equivalent preplant–only N treatments in terms of lodging resistance and seed yield, whereas the highest seed yield was generally attained under the split–N application in all experimental years. Root capacitance and impedance were significantly correlated with root morphological traits, which in turn affected lodging resistance and seed yield, while NDVI was closely related to lodging resistance (P < 0.01). A split–N application strategy with moderate N rates (100–150 kg N ha–1) can be highly recommended for canola production in eastern Canada. Indirect prediction of lodging susceptibility through root electrical measurements and NDVI mapping have high applicability due to their low cost and non–destructive properties, and are expected to serve as high–throughput techniques for guiding N fertilizer management to improve seed yield, while reducing lodging risk. • The trade–off between canola yield and lodging susceptibility was elucidated. • Split–N application with moderate rates can be recommended for canola production. • NDVI and root capacitance were feasible for diagnosing lodging susceptibility risk. [ABSTRACT FROM AUTHOR]

Developing efficient nutrient management regimes is a prerequisite for promoting canola ( Brassica napus L.) as a viable cash crop in eastern Canada. Field experiments were conducted to investigate the growth, yield, and yield components of canola in response to various combinations of preplant and sidedress nitrogen (N) with soil-applied sulfur (S) and soil and foliar-applied boron (B). Canola yield and all its yield components were strongly correlated ( r2 = 0.99) with the amount of N applied, as was the above-ground biomass at 20% flowering and the leaf area index. Sidedress N was more efficiently utilized by the crop, leading to greater yields than preplant N application. On average, canola yields increased by 9.7 kg ha−1 for preplant N application and by 13.7 kg ha−1 for sidedress N application, for every kg N ha−1 applied, in 6 of the 10 site-years. Soil-applied S also increased canola yields by 3-31% in 7 of the 10 site-years, but had no effect on yield components. While there was no change in yield from soil-applied B, the foliar B application at early flowering increased yields up to 10%, indicating that canola plants absorb B efficiently through their leaves. In summary, canola yields were improved by fertilization with N (8 of 10 site-years), S (7 of 10 site-years) and B (4 of 10 site-years). Yield gains were also noted with split N-fertilizer application that involved sidedressing N between the rosette and early flowering stage. Following these fertilizer practices could improve the yield and quality of canola crop grown in rainfed humid regions similar to those in eastern Canada. [ABSTRACT FROM AUTHOR]

BACKGROUND Optical sensing is a potential tool to estimate plant N status, but soil water deficits may interefere with forming a clear relationship. A greenhouse study was conducted with oat plants treated with three water regimes and four N levels to determine whether optical sensing could be used to estimate leaf N and relative water content (RWC). RESULTS Leaf N was strongly correlated with reflectance at 550 nm and at around 705 nm, and N treatments caused a red-edge peak shift to lower wavelength. The ratio of the first derivative reflectance at 741-696 nm (FDRE) was identified to be a good estimator of leaf N at jointing ( R2 = 0.90) and heading ( R2 = 0.86) stages across water treatments. Leaf N also had a stronger association with the red-edge position (REP) at both stages ( R2 = 0.83 and 0.78), or with the ratio R4 (R760/R550) at jointing ( R2 = 0.88), than with chlorophyll meter (SPAD) readings. Under water stress, the predictive accuracy of leaf N increased with these reflectance indices, but decreased using SPAD readings. CONCLUSION The results indicate that specific reflectance indices of FDRE, REP and R4 may be used for a rapid and non-destructive estimation of oat plant N status over a range of water regimes. © 2014 Her Majesty the Queen in Right of Canada Journal of the Science of Food and Agriculture © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Recent development in canopy optical-sensing technology provides the opportunity to apply fertilizer variably at the field scale according to spatial variation in plant growth. A field experiment was conducted in Ottawa, Canada, for two consecutive years to determine the effect of fertilizer nitrogen (N) input at variable- vs. uniform-application strategies at the V6-V8 growth stage, on soil mineral N, canopy reflectance, and grain yield of maize ( Zea mays L.). The variable N rates were calculated using an algorithm derived from readings of average normalized difference vegetation index (NDVI) of about 0.8 m × 4.6 m, and N fertilizer was then applied to individual patches of the same size of NDVI readings (0.8 m × 4.6 m) within a plot (2184 m2). Canopy reflectance, expressed as NDVI, was monitored with a hand-held spectrometer, twice weekly before tasseling and once a week thereafter until physiological maturity. Soil mineral N (0-30 cm depth) was analyzed at the V6 and VT growth stages. Our data show that both variable and uniform-application strategies for N side-dressings based on canopy-reflectance mapping data required less amount of N fertilizer (with an average rate of 80 kg N ha-1 as side-dressing in addition to 30 kg N ha-1 applied at planting), and produced grain yields similar to and higher nitrogen-use efficiency (NUE) than the preplant fully fertilized (180 kg N ha-1) treatment. No difference was observed in either grain yield or NUE between the variable- and uniform-application strategies. Compared to unfertilized or fully fertilized treatments, the enhancements in grain yield and NUE of the variable-rate strategy originated from the later N input as side-dressing rather than the variation in N rates. The variable-rate strategy resulted in less spatial variations in soil mineral N at the VT growth stage and greater spatial variations in grain yield at harvest than the uniform-rate strategy. Both variable- and uniform-application strategies reduced spatial variations in soil mineral N at the VT stage and grain yield compared to the unfertilized treatment. The variable-rate strategy resulted in more sampling points with high soil mineral N than the uniform-rate strategy at the VT stage. [ABSTRACT FROM AUTHOR]

Heterojunctions near infrared (NIR) photodetectors have attracted increasing research interests for their wide-ranging applications in many areas such as military surveillance, target detection, and light vision. A high-performance NIR light photodetector was fabricated by coating the methyl-group terminated Si nanowire array with plasmonic gold nanoparticles (AuNPs) decorated graphene film. Theoretical simulation based on finite element method (FEM) reveals that the AuNPs@graphene/CH3-SiNWs array device is capable of trapping the incident NIR light into the SiNWs array through SPP excitation and coupling in the AuNPs decorated graphene layer. What is more, the coupling and trapping of freely propagating plane waves from free space into the nanostructures, and surface passivation contribute to the high on-off ratio as well. [ABSTRACT FROM AUTHOR]

Humic amendment (HA) is increasingly being evaluated and utilized to improve soil health and crop productivity in intensely farmed arid and semi-arid regions. However, the scientific comparison of field-scale use of single vs. repeated application of HA has not been reported. A field study was conducted to quantify the effect of different numbers of annual HA applications on (i) oat crop performance indicators, and (ii) the changes in soil health metrics in a dryland farming ecosystem. We found that multiple years of annual HA application improved crop growth, and increased grain protein yield (up to 60%), grain yield (21%), water use efficiency (22%), partial factor productivity of nitrogen (21%) and economic benefit (34%) over that for the control (no HA) during both a wetter and a drier growing season. The greater input of crop residue associated with higher yields led to an increase of soil organic carbon and water storage at both 0–20 and 20–60 cm soil layers, and a reduction in soil electrical conductivity, pH and bulk density with increasing years of HA application. There was an overall improvement in soil micro-environmental conditions. These in turn promoted an increased activity of the soil enzymes urease (up to 89%), invertase and catalase and soil nutrient turnover and availability (e.g. up to 58% higher plant available nitrogen). Our results show for the first time that repeated annual HA application of at least 2 years would be a cost-effective strategy to combat land degradation and nurture sustainable crop production in dryland agriculture under widely varying weather scenarios expected with climate change. • Humic amendment (HA) improved grain yield and water use efficiency of oat crop. • Positive effects achieved with two or more annual applications of 1500 kg ha−1. • HA increased soil organic carbon and other properties in the upper and deeper soil layers. • Increased oat productivity was attributed to improved soil health. [ABSTRACT FROM AUTHOR]

Abstract: In this study, boronizing of 99.95% pure cobalt was performed in a solid medium by using Commercial LSB-II powders (that contain SiC) at 850, 900 and 950°C for 2, 4, 6 and 8h, respectively. The surface modified samples were examined by means of scanning electron microscopy (SEM)–energy dispersive spectroscopy (EDS), X-ray diffraction, microhardness tester and ring-on-block wear tester. Samples boronized had Co2B phase or Co2B plus Co2Si phases depending on the process temperatures. The depth of modified layer ranged from 40 to 186μm, depending on treatment temperature and time. The hardness of boride layer is much higher than that of silicide layer and substrate, and the wear resistance of the boride layer is more excellent than that of the silicide layer. [Copyright &y& Elsevier]

p-type ZnSe nanowires (NWs) with tunable electrical conductivity were fabricated on a large scale by evaporating a mixed powder composed of ZnSe and Sb in different ratios. According to the structural characterization, the Sb-doped ZnSe NWs are of single crystalline form and grow along the [001] direction. The presence of Sb in the ZnSe NWs was confirmed by XPS spectra. Electrical measurement of a single ZnSe:Sb NW based back-gate metal-oxide field-effect-transistor reveals that all the doped NWs exhibit typical p-type conduction characteristics, and the conductivity can be tuned over eight orders of magnitude, from 6:36 × 10-7 S cm-1 for the undoped sample to ~37:33 S cm-1 for the heavily doped sample. A crossed p-n nano-heterojunction photodetector made from the as-doped nanostructures displays pronounced rectification behavior, with a rectification ratio as high as 103 at ±5 V. Remarkably, it exhibits high sensitivity to ultraviolet light illumination with good reproducibility and quick photoresponse. Finally, the work mechanism of such a p-n junction based photodetector was elucidated. The generality of the above result suggests that the as-doped p-type ZnSe NWs will find wide application in future optoelectronics devices. [ABSTRACT FROM AUTHOR]

Background Most cavernous sinus dural arteriovenous fistulas (CSDAVFs) present with benign ocular symptoms; isolated CSDAVFs with aggressive behavior are extremely rare. The treatment goal is to occlude the fistula totally. However, transarterial or venous access may not be possible because of complex angioarchitecture. Case description A woman in her late 70s presented with progressive respiratory failure and rapid deterioration of limb muscle power. Imaging studies showed an isolated CSDAVF with exclusive venous drainage to the deep venous system leading to venous hypertension as well as ischemic changes in the brain stem, left thalamus and basal ganglia. Transvascular access of the cavernous sinus (CS) failed. The fistula was eventually occluded by transorbital direct puncture of the posterior CS through the internal carotid artery (ICA) with coils delivered into the CS. The holes in the walls of the ICA created by the puncture needle were sealed by detachable coils and the patient was discharged with mild paresis. Conclusion Although more invasive than the transvascular route and possibly associated with the risk of loss of visual acuity and occurrence of subarachnoid hemorrhage, transorbital direct puncture of the posterior CS through the ICA is an alternative and feasible method to treat isolated aggressive CSDAVFs when access by the transvascular route fails. [ABSTRACT FROM AUTHOR]

Some properties of boride formed on gray cast iron (GCI) have been investigated. GCI was boronized by powder-pack method using Commercial LSB-II powders at 1123, 1173, and 1223K for 2, 4, 6, and 8 h, respectively. Scanning electron microscopy showed that boride formed on the surface of boronized GCI had tooth-shaped morphology. The hardness of boride formed on surfaces of GCI ranged from 1619 to 1343HV0.025, and quenched and tempered GCI ranged from 400 to 610HV0.025. The boride formed in the coating layer confirmed by X-ray diffraction analysis was Fe2B single phase. Depending on boronizing time and temperature, the thickness of coating layers on boronized GCI ranged from 26 to 105 μm. The activation energy was 209 kJ/mol for boronized GCI. Moreover, the possibility of predicting the iso-thickness of boride layers variation was studied. Dry-sliding wear tests showed that the wear resistance of boronized sample was greater than that of quenched and tempered sample. [ABSTRACT FROM AUTHOR]

Human diets containing oat ( Avena sativa L.) grain offer health benefits resulting in an emerging interest in oat improvement. Information on nitrogen (N) uptake, distribution, and use efficiency (NUE) in oat is limited. A greenhouse study using a 15N-labeling technique was conducted to determine the responses of two contrasting oat genotypes to timing and level of N deficiency. Hulled oat cv. Prescott and hulless cv. AC Gehl were grown in soil-mix pot culture with five N treatments applied through modified Hoagland solutions. Differences in 15N accumulation, 15N distribution, plant N originating from the labeled source, and NUE between the contrasting cultivars, were examined for each N strategy. Level of N deficiency and timing of N supply of 15NH415NO3 greatly affected 15N distribution, the origins of plant N, and the amount of 15N recovered in the plant. When N was supplied from seedling emergence to maturity (T1), AC Gehl accumulated 61% more 15N in the shoots, but 46% less 15N in the grain than Prescott (0.43 vs. 0.80 mg plant-1), indicating that AC Gehl was less effective in producing grain yield than Prescott as AC Gehl produced greater total dry matter (DM). Withholding N supply until flag-leaf stage (FL) increased 15N in the grain of both cultivars by 29.6%, resulting in the highest NUE. In most cases, there were larger portions of plant N derived from the labeled source for AC Gehl than for Prescott. Our results suggest that greater NUE in the newly released AC Gehl was associated with N accumulation in the vegetative tissues. It is concluded that genotype improvement of hulless oat should be focused on enhancing N-translocation efficiency. [ABSTRACT FROM AUTHOR]

Abstract: In this study, CoCrMo alloy was boronized at 950°C for 2, 4, 6 and 8h, respectively. The boronized samples were characterized by scanning electron microscopy, X-ray diffraction, microhardness tester and ring-on-block wear tester. X-ray diffraction studies showed the boride layer formed at 950°C for 2–8h consisted of the phases Co2B and CrB. A large number of pores formed in diffusion zone were probably attributed to the Kirkendall effect. Depending on boronizing time, the thickness of boride layer ranged from 4 to 11μm. The excellent wear resistance of the boronized CoCrMo alloy was attributed to the high surface hardness of the Co2B and CrB under dry-sliding conditions when compared to the as-received state. [Copyright &y& Elsevier]

Abstract: Boronizing of CoCrMo alloy has been performed by means of a powder-pack method using commercial LSB powders at 850, 900 and 950°C for 8h, respectively. In this study, the boronized CoCrMo alloy before and after oxidation tests were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The distribution of alloy elements of boronized samples from surface to interior was determined using energy-dispersive X-ray spectroscopy (EDS). XRD study showed the boride layer formed at 950°C/8h consisted of the phases Co2B and CrB. Depending on boronizing temperature, the thickness of boride layer ranged from 2 to 11μm. Cyclic oxidation behavior of the boride layer has been investigated at an oxidation temperature of 950°C with a total exposure time up to 50h in air. The test results indicated that the boronized CoCrMo alloy had superior oxidation resistance compared to unboronized sample. [Copyright &y& Elsevier]

Abstract: In this study, boronizing of 99.9% pure nickel was performed by means of a powder-pack method using Commercial LSB-II powders (that contained SiC) at 850, 900 and 950°C for 2, 4, 6 and 8h, respectively. The coated samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and hardness tests. The presence of boride (Ni2B) and silicide (Ni5Si2, Ni2Si) phases, formed on the surface of boronized pure nickel, were confirmed by X-ray diffraction analysis. The Ni3Si phase was found when pure nickel was boronized at 850°C for 2h. Depending on boronizing time and temperature, the thickness of coating layer ranged from 36 to 237μm. The hardness values were 832 HV0.01 for the silicide layer, 984 HV0.01 for boride layer, and 139 HV0.01 for the Ni substrate. [Copyright &y& Elsevier]

Typical treatment of intracranial aneurysm includes: surgical clipping, intrasacular packing, and parent artery occlusion. The treatment of a fusiform aneurysm is often parent artery occlusion, and keeping patency of the parent artery is difficult. We report our experience in the treatment of 3 cases of intracranial fusiform aneurysm with stent placement inside the parent artery only, without coil packing of the aneurysm lumen. All 3 patients had a non-hemorrhagic dissecting aneurysm in the vertebral artery. They were treated with 2 Helistents, 3 Neuroform stents, and 2 Neuroform stents, respectively. These aneurysms disappeared after treatment at their follow-up angiograms. Treatment with a bare stent may induce obliteration or reduction in the size of some aneurysms. This technique is useful in the treatment of non-hemorrhagic fusiform-shaped aneurysms or non-hemorrhagic dissecting aneurysms to preserve the patency of these parent arteries. [ABSTRACT FROM AUTHOR]

We report our experience with transarterial embolization of traumatic carotid-cavernous fistulae (TCCFs) by using Gugliemi detachable coil (GDC). From 2000 to 2007 at our institution, 11 patients with 12 TCCFs underwent transarterial GDC embolization because of failure to occlude fistulae by detachable balloon with preservation of the parent artery. The cause of the failure to occlude the fistula by detachable balloon was small fistula tract (n=9) and/or tortuous parent artery (n=3) or repeated balloon puncture by bony fragment (n=1). All TCCFs were successfully occluded by a single session transarterial GDC embolization. The average number of coils were eight (range, two-16) with an average length of 104 cm (range, 12-283 cm). No statistically significant procedure-related neurological complication or recurrent TCCF was observed in any of the patients. Transarterial GDC embolization is a useful method in the treatment of TCCFs, particularly in those TCCFs with small fistula tract or small CS. [ABSTRACT FROM AUTHOR]

The purpose of this study was to improve clinical assessment of carotid-blowout syndrome (CBS) in patients with head-and-neck cancers and with covered stents by evaluating immediate and delayed complications of reconstructive management. Eleven such patients were treated with self-expandable covered stents. We evaluated immediate and delayed complications by assessing clinical and imaging findings. Technical success and immediate hemostasis were achieved in all patients. Immediate complications were noted in four patients (36.4%), including thromboembolism in three patients and, in one patient, dissection of the carotid artery and type III endoleak by the overlapped self-expandable stent causing rebleeding. Delayed complications were noted in eight patients (72.7%), including six episodes of rebleeding in five patients, distal marginal stenosis in five patients, and delayed carotid thrombosis in three patients (one with brain abscess formation). We suggest close follow-up of the patients and aggressive re-intervention of their complications to improve outcomes. [ABSTRACT FROM AUTHOR]

The hepatopulmonary syndrome (HPS) results from intrapulmonary vasodilation in the setting of cirrhosis and portal hypertension. In experimental HPS, pulmonary endothelial endothelin B (ETB) receptor overexpression and increased circulating endothelin-1 (ET-1) contribute to Vasodilation through enhanced endothelial nitric oxide synthase (eNOS)-derived nitric oxide (NO) production. In both experimental cirrhosis and prehepatic portal hypertension, ETB receptor overexpression correlates with increased vascular shear stress, a known modulator of ETB receptor expression. We investigated the mechanisms of pulmonary endothelial ETB receptor-mediated eNOS activation by ET-1 in vitro and in vivo. The effect of shear stress on ETB receptor expression was assessed in rat pulmonary microvascular endothelial cells (RPMVECs). The consequences of ETB receptor overexpression on ET-1-dependent ETB receptor-mediated eNOS activation were evaluated in RPMVECs and in prehepatic portal hypertensive animals exposed to exogenous ET-1. Laminar shear stress increased ETB receptor expression in RPMVECs without altering mRNA stability. Both shear-mediated and targeted overexpression of the ETB receptor enhanced ET-1-mediated ETB receptor-dependent eNOS activation in RPMVECs through Ca2+-mediated signaling pathways and independent of Akt activation. In prehepatic portal hypertensive animals relative to control, ET-1 administration also activated eNOS independent of Akt activation and triggered HPS. These findings support that increased pulmonary microvascular endothelial ETB receptor expression modulates ET-1-mediated eNOS activation, independent of Akt, and contributes to the development of HPS. [ABSTRACT FROM AUTHOR]

Recently, we proposed a simple, large-scale hydrothermal synthesis of flexible nanocables with silver as cores and cross-linked poly(vinyl alcohol) (PVA) as shells in which silver ions catalyzed the cross-linking of PVA chains under hydrothermal conditions and a so-called synergistic soft−hard template mechanism (SSHM) was proposed (Luo et al. J. Am. Chem. Soc. 2005, 127, 2822−2823). In this paper, we extend this approach to examine whether high valent metal ions such as Te4+ also can be reduced under a similar reaction but using sodium tellurite and PVA as precursors. The results demonstrated that different tellurium/cross-linked PVA core−shell nanostructures such as a core−shell structure with nanorod bundles penetrated through a ball, branched cables, and separated cables can be synthesized. The influence of the concentration of PVA, reaction temperature, and reaction time on the formation of different nanostructures has been investigated. In addition, the detailed reaction and shape evolution process of core−shell structures have also been studied. The results suggested that the cross-linking of PVA also can occur in the presence of high valent metal ions besides noble metal ions, underlining that it is possible to access various core−shell structures with different inorganic components as cores by this approach. [ABSTRACT FROM AUTHOR]

Assesses the role of endothelin-1 (ET-1) in the molecular and physiological changes associated with experimental hepatopulmonary syndrome (HPS) by evaluating partial portal vein ligation (PVL), biliary and (thiocetamide treatment) TAA-induced cirrhosis. Evaluation for HPS in rat perihepatic portal hypertension, biliary and nonbiliary TAA cirrhosis; Finding that HPS developed only in biliary cirrhosis in association with increased plasma ET-1 and TNF-α levels and the development of molecular changes in the pulmonary microvasculature; Observation that ET-1 and TNF-α interact to trigger pulmonary microvascular changes in experimental HPS.

Hypochlorous acid (HClO/ClO−) is a key reactive oxidative species (ROS) in the body. The HClO/ClO− concentrations are imbalanced during cancer formation due to the ROS stress response. This paper introduces a novel chitosan-based self-calibration fluorescent nanoprobe (ChCyNil) constructed by molecular assembly for the ratiometric detection of HClO/ClO−. Two chromophores with different fluorescence characteristics and HClO/ClO− sensitivity were labeled on chitosan, and nanoparticles were prepared by a self-assembly strategy for HClO/ClO− detection. ChCyNil exhibits several advantages, such as dual near-infrared emissions at 670 nm and 845 nm, tunable fluorescence intensity, self-calibration fluorescence, and good biocompatibility, improving its accuracy in HClO/ClO− detection. Our study confirmed that ChCyNil exhibits a well-assembled spheroidal nanostructure and good photophysical properties in solution. The fluorescence imaging properties were further proved by detecting endogenous HClO/ClO− produced by LPS/PMA stimuli in cells and zebrafish. In addition, ChCyNil was used to detect the fluorescence behavior of HClO/ClO− in tumors of live mice. The successful design and fabrication of ChCyNil have presented a new strategy for constructing detection tools with improved fluorescence properties for HClO/ClO− in live animals. [Display omitted] • A chitosan-based nanoprobe ChCyNil for HClO/ClO− was constructed by self-assembly • ChCyNil has two emission signals at 670 nm and 845 nm with self-calibration property • ChCyNil exhibits good biocompatibility, tunable fluorescence, and improved accuracy • These near-infrared emissions make ChCyNil suitable for HClO/ClO− detection in vivo [ABSTRACT FROM AUTHOR]

Hypochlorous acid (HClO/ClO−) is a key reactive oxidative species (ROS) in the body. The HClO/ClO− concentrations are imbalanced during cancer formation due to the ROS stress response. This paper introduces a novel chitosan-based self-calibration fluorescent nanoprobe (ChCyNil) constructed by molecular assembly for the ratiometric detection of HClO/ClO−. Two chromophores with different fluorescence characteristics and HClO/ClO− sensitivity were labeled on chitosan, and nanoparticles were prepared by a self-assembly strategy for HClO/ClO− detection. ChCyNil exhibits several advantages, such as dual near-infrared emissions at 670 nm and 845 nm, tunable fluorescence intensity, self-calibration fluorescence, and good biocompatibility, improving its accuracy in HClO/ClO− detection. Our study confirmed that ChCyNil exhibits a well-assembled spheroidal nanostructure and good photophysical properties in solution. The fluorescence imaging properties were further proved by detecting endogenous HClO/ClO− produced by LPS/PMA stimuli in cells and zebrafish. In addition, ChCyNil was used to detect the fluorescence behavior of HClO/ClO− in tumors of live mice. The successful design and fabrication of ChCyNil have presented a new strategy for constructing detection tools with improved fluorescence properties for HClO/ClO− in live animals. [Display omitted] • A chitosan-based nanoprobe ChCyNil for HClO/ClO− was constructed by self-assembly • ChCyNil has two emission signals at 670 nm and 845 nm with self-calibration property • ChCyNil exhibits good biocompatibility, tunable fluorescence, and improved accuracy • These near-infrared emissions make ChCyNil suitable for HClO/ClO− detection in vivo [ABSTRACT FROM AUTHOR]

Examines whether low levels of circulating endothelin-1 (ET-1), arising during chronic hepatic injury, can induce pulmonary endothelial nitric oxide synthase expression. Role of ET-1 in nitric oxide production; Contribution of ET-1 to the development of intrapulmonary vasodilation and hepatopulmonary syndrome.

Although much investigated, the factors constraining cereal grain protein accumulation are not well understood. As a result of the development of a new technique, new approaches to this question are now possible. A peduncle perfusion system was used to deliver a range of plant growth regulators (PGRs) and/or N solutions into barley (Hordeum vulgare) plants during the grain-filling period. The perfusion technique floods the peduncle interior with a treatment solution for periods of weeks to months, allowing the plant to take up administered substances from the perfused solution. The objectives of the present work were to determine: (1) whether some PGRs could alter the overall pattern of N allocation within barley plants, perhaps leading to higher protein accumulation in the seeds, (2) whether the addition of N through the peduncle could increase the seed N concentration even when the concentration of N in the rooting medium was high, and (3) whether or not PGR-stimulated elevations in grain protein levels and peduncle-added N increases in grain protein levels were additive. Three experiments were conducted to determine the physiological effects of (1) peduncle-administered PGRs (2) combinations of soil- and peduncle-applied N and (3) selected combinations of soil- and peduncle-administered N, and peduncle-applied PGRs on photosynthetic rate, dry matter partitioning and N accumulation of barley plants during grain filling. The first experiment tested four PGRs: abscisic acid (ABA), kinetin, gibberellic acid (GA3), and 2,4-dichlorophenoxy acetic acid (2,4-D) each at three concentrations. The second experiment tested three levels of soil N (NH4NO3) fertility, and two concentrations of peduncle-added N (urea). The third experiment tested four PGRs: ABA, kinetin, GA3, and 2,4-D with two soil N concentrations and two concentrations of peduncle-added N. ABA and 2,4-D decreased total seed weight of the perfused spike. The addition of peduncle-perfused N increased seed protein concentratin and content under conditions of high soil N fertility, suggesting that seed protein accumulation is more limited by the ability of roots to take up N from the soil than by the seed to take up N from the rest of the plant. The effects of the PGRs on N allocation among plant parts varied with the amount of N available to the lant. Because it resulted in less protein stored in the flag leaf and more in the seeds. GA3 perfusion caused an overall change in the allocation of N among plant parts. Peduncle perfusion of Kinetin and ABA affected some aspects of photosynthetic physiology. [ABSTRACT FROM AUTHOR]

Ecologically relevant low UV-B is reported to alter reactive oxygen species metabolism and anti-oxidative systems through an up-regulation of enzymes of the phenylpropanoid pathway. However, little is known about low UV-B-induced changes in carotenoid profile and their impacts on light harvesting and photoprotection of photosystem II (PSII) in plants. We investigated carotenoids profile, chlorophyll pigments, phenolics, photosynthetic efficiency and growth in Arabidopsis thaliana (Col-0) plants grown under photosynthetically active radiation (PAR), PAR+ ultraviolet (UV)-A and PAR+UV-A+B regimes for 10 days in order to assess plant acclimation to low UV-B radiation. A chlorophyll fluorescence assay was used to examine UV-B tolerance in plants further exposed to acute high UV-B for 4 and 6 h following a 10-day growth under different PAR and UV regimes. We found that both PAR+ UV-A and PAR+UV-A+B regimes had no negative effect on quantum efficiency, electron transport rate, rosette diameter, relative growth rate and shoot dry weight of plants. Chronic PAR+ UV-A regime considerably (P < 0.05) increased violaxanthin (26 %) and neoxanthin (92 %) content in plants. Plant exposure to chronic PAR+UV-A+B significantly (P < 0.05) increased violaxanthin (48 %), neoxanthin (63 %), lutein (33 %), 9-cis ß-carotene (28 %), total ß-carotene (29 %) and total phenolics (108 %). The maximum photochemical efficiency (F v /F m) in leaves was found to be positively correlated with total phenolics (rho = 0.81 and rho = 0.91, P < 0.05 for 4 and 6 h, respectively) and non-photochemical quenching (q N) (rho = 0.81 and rho = 0.84, P < 0.05 for 4 and 6 h, respectively) in plants exposed to acute high UV-B for 4 and 6 h following a 10-day growth under chronic PAR+UV-A+B. There was also a significant positive correlation (rho = 0.93, P < 0.01) between q N and lutein content in the plants exposed to acute high UV-B stress for 4 h following plant exposure to chronic PAR+UV-A+B. The findings from our study indicate that plants grown under chronic PAR+UV-A+B displayed higher photoprotection of PSII against acute high UV-B stress than those grown under PAR and PAR+ UV-A regimes. An induction of phenolics and lutein-mediated development of q N were involved in the photoprotection of PSII against UV-B-induced oxidative stress. [ABSTRACT FROM AUTHOR]

The metal-insulator transition (MIT) with large change in electric resistance offers the electronic devices great application prospects whatsoever limited by its gap formation mechanisms such as complex electron correlation or magnetic ordering effects. In the past, studies on Slater-type insulators based on antiferromagnetic (AFM)-ordering-induced MIT effect were only limited to high atomic number transition metal oxides (TMO). In this paper, we predict a Slater-type insulator based on spin-web Cu 3 TeO 6 in AFM ground state by simulating the formation progress of MIT using density functional theory (DFT) and the local spin density approximation (LSDA) + U (Hubbard parameter). The molecular bonding relevant with orbital hybridization between Cu-3 d and O-2 p states are analyzed. [ABSTRACT FROM AUTHOR]