Phosphorus is an essential macronutrient for plant growth and development. Root system architecture (RSA) affects a plant's ability to obtain phosphate, the major form of phosphorus that plants ...uptake. In this review, I first consider the relationship between RSA and plant phosphorus‐acquisition efficiency, describe how external phosphorus conditions both induce and impose changes in the RSA of major crops and of the model plant Arabidopsis, and discuss whether shoot phosphorus status affects RSA and whether there is a universal root developmental response across all plant species. I then summarize the current understanding of the molecular mechanisms governing root developmental responses to phosphorus deficiency. I also explore the possible reasons for the inconsistent results reported by different research groups and comment on the relevance of some studies performed under laboratory conditions to what occurs in natural environments.
This review presents the root developmental responses of major crops and Arabidopsis to phosphorus nutrition, discuss the factors that affect these responses, and summarizes our current understandings of the molecular mechanisms underlying these responses.
Ultra-compact X-ray binaries (UCXBs) are low-mass X-ray binaries with ultra-short orbital periods (usually less than 1 hr) and hydrogen-poor donor stars, which are proposed to be potential Laser ...Interferometer Space Antenna (LISA) sources. In this work, we first employ the Modules for Experiments in Stellar Astrophysics code to examine the parameter space of the progenitors of UCXBs that LISA will detect. Our simulations indicate that the initial binaries with a neutron star and a companion star, in an orbit of initial orbital period smaller than the bifurcation period, could evolve into UCXBs, some of which will emit gravitational wave signals that can be detectable by LISA. However, the initial orbital periods of the binaries that will evolve into UCXB-LISA sources in a distance of 10 kpc are located in a very narrow range, i.e., the formation of these LISA source requires an extreme fine-tuning of initial parameter. According to the characteristic strains and the derived maximum detectable distances, four sources among eight UCXBs with the observed distances are expected to be detected by LISA. Based on the parameter space given by the detailed binary evolution models and the rapid binary star evolution code, the birthrate of UCXBs appearing as LISA sources in the Galaxy is estimated to be . Considering the contribution of UCXBs in globular clusters, the number of UCXB-LISA sources can reach 240-320. Although the formation condition is severe, the detectability of UCXBs by LISA is still significant because it provides an opportunity to pursue full multi-messenger investigations.
•Overview of nanomaterial immobilized enzyme.•Binding force for enzyme immobilization.•Performance of nanomaterial immobilized enzyme.•Application of immobilized enzyme.•Outlook of nanomaterial in ...enzyme immobilization.
Enzymes have been widely used because of their catalytic properties, and immobilization is a promising technique to improve their catalytic activity and stability. Due to their large specific surface areas, exceptional chemical, mechanical, thermal and cost effective characteristics, nanomaterials should be ideal carriers for the immobilization of enzymes. Enzymes immobilized on nano-carriers are more robust and stable, and can be recycled and reused. This review focuses on the nanomaterial immobilized enzymes and their applications. The introduction addresses the advantages of immobilized enzymes and the features of enzyme immobilization nanocarriers. The next section covers carbonaceous nanomaterials used in enzymes immobilization, with subsections on carbon nanotube, graphene, graphene oxide and reduced graphene oxide. The third section treats metallic nanomaterials for enzymes immobilization, with subsections on metal (gold), metal oxide (titanium dioxide, zinc oxide) and metal hydroxide (layered double hydroxide) nanomaterials. Then, the next section summarizes the applications of nanomaterial immobilized enzymes. A concluding section discusses the challenges and prospects of nanomaterial immobilized enzymes.
Acetylcholinesterase (AChE) is popularly used in biological and chemical sensors since it can be inhibited or reactivated. As the inhibitor of AChE is meaningful for many neurodegenerative diseases ...caused by the lack of AChE substrate acetylcholine (ACh), and the reactivator of inhibited AChE is helpful to treat the blocked neurotransmission resulted from the excessive ACh. Therefore, it is significant to screen AChE inhibitors and reactivators for pharmaceutical application. In addition, the detection of pesticides and heavy metals is of great importance to food safety and environment. So, based on the inhibition of AChE by pesticides and heavy metals, AChE can also be used in food safety and environmental analysis. Colorimetric method is a popular strategy for AChE assay due to its low cost, practicality and simplicity. In this review, we focus on the colorimetric method for AChE assay and the corresponding applications. The basic principles, advantages and disadvantages of Ellman's method, pH indicator-, 3,3′,5,5′-tetramethylbenzidine- (TMB-), noble metal nanomaterial-, and substrate-based colorimetric method are evaluated. In addition, the applications of colorimetric AChE assays in inhibitors and reactivators screening, pesticides and heavy metals detection are reviewed. Finally, the conclusions and future perspectives are provided.
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•Different chromogenic reagent-based colorimetric method for AChE are reviewed.•The mechanism, advantage and disadvantage of colorimetric AChE assay are discussed.•The applications of colorimetric AChE assays in analysis are reviewed.•A perspective for the colorimetric AChE assay is proposed.
In contrast to the wealth of asymmetric transformations for generating central chirality from alkyl radicals, the enantiocontrol over the allenyl radicals for forging axial chirality represents an ...uncharted domain. The challenge arises from the unique elongated linear configuration of the allenyl radicals that necessitates the stereo‐differentiation of remote motifs away from the radical reaction site. We herein describe a copper‐catalyzed asymmetric radical 1,4‐carboalkynylation of 1,3‐enynes via the coupling of allenyl radicals with terminal alkynes, providing diverse synthetically challenging tetrasubstituted chiral allenes. A chiral N,N,P‐ligand is crucial for both the reaction initiation and the enantiocontrol over the highly reactive allenyl radicals. The reaction features a broad substrate scope, covering a variety of (hetero)aryl and alkyl alkynes and 1,3‐enynes as well as radical precursors with excellent functional group tolerance.
A copper‐catalyzed asymmetric radical 1,4‐carboalkynylation of 1,3‐enynes is realized, providing diverse tetrasubstituted chiral allenes. The utilization of the copper/chiral N,N,P‐ligand is crucial for the enantiocontrol over the allenyl radicals, which is difficult due to their elongated linear configuration that necessitates the stereo‐differentiation of remote motifs away from the reaction site.
Tocilizumab (TCZ), a monoclonal antibody against interleukin‐6 (IL‐6), emerged as an alternative treatment for COVID‐19 patients with a risk of cytokine storms recently. In the present study, we ...aimed to discuss the treatment response of TCZ therapy in COVID‐19 infected patients. The demographic, treatment, laboratory parameters of C‐reactive protein (CRP) and IL‐6 before and after TCZ therapy and clinical outcome in the 15 COVID‐19 patients were retrospectively assessed. Totally 15 patients with COVID‐19 were included in this study. Two of them were moderately ill, six were seriously ill and seven were critically ill. The TCZ was used in combination with methylprednisolone in eight patients. Five patients received the TCZ administration twice or more. Although TCZ treatment ameliorated the increased CRP in all patients rapidly, for the four critically ill patients who received an only single dose of TCZ, three of them (No. 1, 2, and 3) still dead and the CRP level in the rest one patient (No. 7) failed to return to normal range with a clinical outcome of disease aggravation. Serum IL‐6 level tended to further spiked firstly and then decreased after TCZ therapy in 10 patients. A persistent and dramatic increase of IL‐6 was observed in these four patients who failed treatment. TCZ appears to be an effective treatment option in COVID‐19 patients with a risk of cytokine storms. And for these critically ill patients with elevated IL‐6, the repeated dose of the TCZ is recommended.
Research Highlights
TCZ benefits the COVID‐19 patients in relieving inflammatory activity.
Repeat doses of TCZ is recommended for critically ill COVID‐19 patients.
More cases are still needed to further verify the effect of TCZ.
Caching popular contents at base stations (BSs) can reduce the backhaul cost and improve the network throughput. Yet whether locally caching at the BSs can improve the energy efficiency (EE), a major ...goal for fifth generation cellular networks, remains unclear. Due to the entangled impact of various factors on EE such as interference level, backhaul capacity, BS density, power consumption parameters, BS sleeping, content popularity, and cache capacity, another important question is what are the key factors that contribute more to the EE gain from caching. In this paper, we attempt to explore the potential of EE of the cache-enabled wireless access networks and identify the key factors. By deriving closed-form expression of the approximated EE, we provide the condition when the EE can benefit from caching, find the optimal cache capacity that maximizes the network EE, and analyze the maximal EE gain brought by caching. We show that caching at the BSs can improve the network EE when power efficient cache hardware is used. When local caching has EE gain over not caching, caching more contents at the BSs may not provide higher EE. Numerical and simulation results show that the caching EE gain is large when the backhaul capacity is stringent, interference level is low, content popularity is skewed, and when caching at pico BSs instead of macro BSs.
The chemical effects of hydrogen addition on premixed laminar low-pressure dimethyl ether flames were studied by kinetic analysis. The chemical effects of hydrogen addition on flame structures and ...mole fractions of major species, intermediate species and free radicals have been distinguished clearly from the dilution and thermal effects. The results show that the chemical effects of hydrogen addition cause the DME profile to move toward the upstream side and can suppress the production of acetylene and ethylene. The production of formaldehyde is promoted by the chemical effects of hydrogen addition but the dilution and thermal effects are more dominant which decrease the mole fraction of formaldehyde so that the overall effects make formaldehyde mole fraction decrease. The dominant effects of hydrogen addition on H, OH and O radicals are the chemical effects that make mole fractions of these radicals increase.
•Chemical effects of H2 addition on DME flames are isolated from other effects.•Chemical effects of H2 addition suppress the production of C2H2 and C2H4.•The production of CH2O is promoted by the chemical effects of H2 addition.•H, OH and O radicals increase caused by the chemical effects of H2 addition.
The ADJUVANT study reported the comparative superiority of adjuvant gefitinib over chemotherapy in disease-free survival of resected EGFR-mutant stage II-IIIA non-small cell lung cancer (NSCLC). ...However, not all patients experienced favorable clinical outcomes with tyrosine kinase inhibitors (TKI), raising the necessity for further biomarker assessment. In this work, by comprehensive genomic profiling of 171 tumor tissues from the ADJUVANT trial, five predictive biomarkers are identified (TP53 exon4/5 mutations, RB1 alterations, and copy number gains of NKX2-1, CDK4, and MYC). Then we integrate them into the Multiple-gene INdex to Evaluate the Relative benefit of Various Adjuvant therapies (MINERVA) score, which categorizes patients into three subgroups with relative disease-free survival and overall survival benefits from either adjuvant gefitinib or chemotherapy (Highly TKI-Preferable, TKI-Preferable, and Chemotherapy-Preferable groups). This study demonstrates that predictive genomic signatures could potentially stratify resected EGFR-mutant NSCLC patients and provide precise guidance towards future personalized adjuvant therapy.
Seed plants have evolved to maintain the dormancy of freshly matured seeds until the appropriate time for germination. Seed dormancy and germination are distinct physiological processes, and the ...transition from dormancy to germination is not only a critical developmental step in the life cycle of plants but is also impor- tant for agricultural production. These processes are precisely regulated by diverse endogenous hormones and environmental cues. Although ABA （abscisic acid） and GAs （gibberellins） are known to be the primary phytohormones that antagonistically regulate seed dormancy, recent findings demonstrate that another phytohormone, auxin, is also critical for inducing and maintaining seed dormancy, and therefore might act as a key protector of seed dormancy. In this review, we summarize our current understanding of the sophisticated molecular networks involving the critical roles of phytohormones in regulating seed dormancy and germination, in which AP2-domain-containing transcription factors play key roles. We also discuss the interactions （crosstalk） of diverse hormonal signals in seed dormancy and germination, focusing on the ABA/GA balance that constitutes the central node.
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