The self coupling
λ
of the Higgs boson in the Standard Model may show critical behavior, i.e. the Higgs potential may have a point at an energy scale
∼
10
17
-
18
GeV where both the first and second ...derivatives (almost) vanish. In this case the Higgs boson can serve as inflaton even if its nonminimal coupling to the curvature scalar is only
O
(
10
)
, thereby alleviating concerns about the perturbative unitarity of the theory. We find that just before the Higgs as inflaton enters the flat region of the potential the usual slow-roll conditions are violated. This leads to “overshooting” behavior, which in turn strongly enhances scalar curvature perturbations because of the excitation of entropic (non-adiabatic) perturbations. For appropriate choice of the free parameters these large perturbations occur at length scales relevant for the formation of primordial black holes. Even if these perturbations are not quite large enough to trigger copious black hole formation, they source second order tensor perturbations, i.e. primordial gravitational waves; the corresponding energy density can be detected by the proposed space-based gravitational wave detectors DECIGO and BBO.
The nuclear receptor PPARs are fundamentally important for energy homeostasis. Through their distinct yet overlapping functions and tissue distribution, the PPARs regulate many aspects of energy ...metabolism at the transcriptional level. Functional impairment or dysregulation of these receptors leads to a variety of metabolic diseases, while their ligands offer many metabolic benefits. Studies of these receptors have advanced our knowledge of the transcriptional basis of energy metabolism and helped us understand the pathogenic mechanisms of metabolic syndrome.
Effective manipulation of phonons is crucial to modern energy‐information science and technologies but limited by the charge neutral and spinless nature of phonons. Recently, novel quantum concepts, ...including Berry phase, topology, and pseudospin, are introduced to phonon systems, providing fundamentally new routes to control phonons, opening an emerging field of “topological phononics.” Here, the basic concepts of Berry phase, topology, and pseudospin for phonons are introduced. Also, recent research progresses on various phononic topological states are reviewed, including phononic Su‐Schrieffer‐Heeger‐like states in 1D, quantum anomalous Hall‐like states, quantum valley Hall‐like states, and quantum spin Hall‐like states in 2D, and phononic Weyl points, nodal lines, and topological insulators in 3D. In addition to the fundamental models, material realizations and potential applications of topological phononics are comprehensively presented.
Phononic topological states are comprehensively discussed, including Su‐Schrieffer‐Heeger‐like states in 1D, quantum anomalous/valley/spin Hall‐like states in 2D, and phononic topological insulators and topological semimetals in 3D. An overview of topological phononics from fundamental models to real materials is also provided, followed by an outlook on future experiments and potential applications of this emerging research field.
Abstract
Background
The emergence of coronavirus disease 2019 (COVID-19) is a major healthcare threat. The current method of detection involves a quantitative polymerase chain reaction (qPCR)–based ...technique, which identifies the viral nucleic acids when present in sufficient quantity. False-negative results can be achieved and failure to quarantine the infected patient would be a major setback in containing the viral transmission. We aim to describe the time kinetics of various antibodies produced against the 2019 novel coronavirus (SARS-CoV-2) and evaluate the potential of antibody testing to diagnose COVID-19.
Methods
The host humoral response against SARS-CoV-2, including IgA, IgM, and IgG response, was examined by using an ELISA-based assay on the recombinant viral nucleocapsid protein. 208 plasma samples were collected from 82 confirmed and 58 probable cases (qPCR negative but with typical manifestation). The diagnostic value of IgM was evaluated in this cohort.
Results
The median duration of IgM and IgA antibody detection was 5 (IQR, 3–6) days, while IgG was detected 14 (IQR, 10–18) days after symptom onset, with a positive rate of 85.4%, 92.7%, and 77.9%, respectively. In confirmed and probable cases, the positive rates of IgM antibodies were 75.6% and 93.1%, respectively. The detection efficiency by IgM ELISA is higher than that of qPCR after 5.5 days of symptom onset. The positive detection rate is significantly increased (98.6%) when combining IgM ELISA assay with PCR for each patient compared with a single qPCR test (51.9%).
Conclusions
The humoral response to SARS-CoV-2 can aid in the diagnosis of COVID-19, including subclinical cases.
The time kinetics of humoral responses against the novel coronavirus (SARS-CoV-2) are characterized in patients with COVID-19 by nucleocapsid-based enzyme-linked immunosorbent assay. The antibody testing can aid in the diagnosis of COVID-19 when combined with quantitative polymerase chain reaction, including in subclinical cases.
Organic field-effect transistors (OFETs) are promising for numerous potential applications but suffer from poor charge injection, such that their performance is severely limited. Recent efforts in ...lowering contact resistance have led to significantly improved field-effect mobility of OFETs, up to 100 times higher, as the results of careful choice of contact materials and/or chemical treatment of contact electrodes. Here we review the innovative developments of contact engineering and focus on the mechanisms behind them. Further improvement toward Ohmic contact can be expected along with the rapid advance in material research, which will also benefit other organic and electronic devices.
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•Tea catechins were studied for their combined antioxidant and cytotoxic effects.•EGCG presented the highest Cu2+ chelating ability.•67.4% ECG and 32.6% EGCG was the optimal ...combination (OPC)•OPC enhanced the anti-proliferative activity towards OVCAR-3, HEK293 and HFL1 cells.•OPC enhanced the bitterness and astringency of the chrysanthemum beverage model.
The effects of epigallocatechin gallate (EGCG), epigallocatechin (EGC) and epicatechin gallate (ECG) on the chemical and cell-based antioxidant activity, sensory properties, and cytotoxicity of a catechin-free model beverage were modeled using response surface methodology. Results showed that ECG presented the highest reducing capacity while EGCG presented the highest Cu2+ chelating ability. Binary interactions (EGCG/EGC and EGCG/ECG) had an additive effect on CUPRAC, DPPH and Cu2+ chelating ability. The mixture containing 67.4% ECG and 32.6% EGCG was the optimal combination of flavanols (OPC). In a beverage model – chrysanthemum tea – OPC enhanced the anti-proliferative activity in relation to OVCAR-3, HEK293 and HFL1 cells and decreased the intracellular generation of reactive oxygen species. OPC enhanced the bitterness and astringency of the beverage models impacting in a decrease in overall acceptance. The pasteurization process did not decrease the antioxidant activity and the flavanol concentration of the beverages.
The practice of intercropping, which involves growing more than one crop simultaneously during the same growing season, is becoming more important for increasing soil quality, land-use efficiency, ...and subsequently crop productivity. The present study examined changes in soil physicochemical properties, enzymatic activity, and microbial community composition when walnut (
spp.) was intercropped with tea (
L.) plants in a forest and compared with a walnut and tea monocropping system. The results showed that walnut-tea intercropping improved the soil nutrient profile and enzymatic activity. The soil available nitrogen (AN), available phosphorus (AP), available potassium (AK), organic matter (OM) content, and sucrase activity were significantly boosted in intercropped walnut and tea than in monocropping forests. The interaction between crops further increased bacterial and fungal diversity when compared to monoculture tea forests. Proteobacteria, Bacteroidetes, Firmicutes, Chlamydiae, Rozellomycota, and Zoopagomycota were found in greater abundance in an intercropping pattern than in monoculture walnut and tea forest plantations. The walnut-tea intercropping system also markedly impacted the abundance of several bacterial and fungal operational taxonomic units (OTUs), which were previously shown to support nutrient cycling, prevent diseases, and ameliorate abiotic stress. The results of this study suggest that intercropping walnut with tea increased host fitness and growth by positively influencing soil microbial populations.
The plant vacuole is an important organelle for storing excess iron (Fe), though its contribution to increasing the Fe content in staple foods remains largely unexplored. In this study we report the ...isolation and functional characterization of two rice genes OsVIT1 and OsVIT2, orthologs of the Arabidopsis VIT1. Transient expression of OsVIT1:EGFP and OsVIT2:EGFP protein fusions revealed that OsVIT1 and OsVIT2 are localized to the vacuolar membrane. Ectopic expression of OsVIT1 and OsVIT2 partially rescued the Fe2+‐ and Zn2+‐sensitive phenotypes in yeast mutant Δccc1 and Δzrc1, and further increased vacuolar Fe2+, Zn2+ and Mn2+ accumulation. These data together suggest that OsVIT1 and OsVIT2 function to transport Fe2+, Zn2+ and Mn2+ across the tonoplast into vacuoles in yeast. In rice, OsVIT1 and OsVIT2 are highly expressed in flag leaf blade and sheath, respectively, and in contrast to OsVIT1, OsVIT2 is highly responsive to Fe treatments. Interestingly, functional disruption of OsVIT1 and OsVIT2 leads to increased Fe/Zn accumulation in rice seeds and a corresponding decrease in the source organ flag leaves, indicating an enhanced Fe/Zn translocation between source and sink organs, which might represent a novel strategy to biofortify Fe/Zn in staple foods.
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