Pseudo-Nambu-Goldstone dark matter can interact with Standard Model fermion through the Higgs portal, and some models can emerge a cancellation mechanism that helps to escape the stringent ...constraints from direct detection experiments. In this paper we explore new constraints of these cancellation models on parameter space of non-zero momentum transfer, from both the current direct detection experiment and the neutron star temperature via the dark matter reheating mechanism.
A
bstract
We present two alternative proofs for the cancellation mechanism in the U(1) symmetric pseudo-Nambu-Goldstone-Boson Dark Matter (pNGB DM) model. They help us to have a better understanding ...of the mechanism from multi-angle, and inspire us to propose some interesting generalizations. In the first proof, we revisit the non-linear representation method and rephrase the argument with the interaction eigenstates. In this picture, the phase mode (DM) can only have a trilinear interaction with a derivative-squared acting on the radial mode when the DM is on-shell. Thus, the DM-quark scattering generated by a mass mixing between the radial mode and the Higgs boson vanishes in the limit of zero-momentum transfer. Using the same method, we can easily generalize the model to an SO(N) model with general soft-breaking structures. In particular, we study the soft-breaking cubic terms and identify those terms which preserve the cancellation mechanism for the DM candidate. In our discussion of the second method, we find that the cancellation relies on the special structure of mass terms and interactions of the mediators. This condition can be straightforwardly generalized to the vector-portal models. We provide two examples of the vector-portal case where the first one is an SU(2)
L
× U(1)
Y
× U(1)
X
model and the second one is an SU(2)
L
× U(1)
Y
× U(1)
B−L
× U(1)
X
model. In the first model the vector mediators are the
Z
μ
boson and a new U(1)
X
gauge boson
X
ν
, while in the second model the mediators are the U(1)
B−L
and U(1)
X
gauge bosons. The cancellation mechanism works in both models when there are no generic kinetic mixing terms for the gauge bosons. Once the generic kinetic mixing terms are included, the first model requires a fine-tuning of the mixing parameter to avoid the stringent direct detection bound, while the second model can naturally circumvent it.
Fused Deposition Modeling (FDM) can be used to manufacture any complex geometry and internal structures, and it has been widely applied in many industries, such as the biomedical, manufacturing, ...aerospace, automobile, industrial, and building industries. The purpose of this research is to characterize the polylactic acid (PLA) and polyethylene terephthalate glycol (PETG) materials of FDM under four loading conditions (tension, compression, bending, and thermal deformation), in order to obtain data regarding different printing temperatures and speeds. The results indicated that PLA and PETG materials exhibit an obvious tensile and compression asymmetry. It was observed that the mechanical properties (tension, compression, and bending) of PLA and PETG are increased at higher printing temperatures, and that the effect of speed on PLA and PETG shows different results. In addition, the mechanical properties of PLA are greater than those of PETG, but the thermal deformation is the opposite. The above results will be a great help for researchers who are working with polymers and FDM technology to achieve sustainability.
Antibiotic resistance genes (ARGs) in the environment are promoted by anthropogenic activities, which cause potential risks to human health. However, large-scale quantitative data on antibiotic ...resistome from the pristine and anthropogenic environments remains largely unexplored. Here, we used metagenome-wide analysis to investigate the share and divergence in ARG profiles and their potential bacterial hosts between the pristine and gut-associated environments. We found that the abundance of total ARGs in gut-associated environments was significantly higher than the pristine environments (P < 0.001). The mcr-1 and tetX, the genes resistant to the last resort antibiotics (colistin and tigecycline, respectively), were in high abundance (4.57 copies/Gb and 3.39 copies/Gb, respectively) in gut-associated environments, suggesting the ARG pollution caused by anthropogenic antibiotics. Metagenomic assembly-based host-tracking analysis identified Escherichia, Bacteroides, and Clostridium as the predominant bacterial hosts of ARGs in gut-associated environments, while Alteromonas, Vibrio, and Proteobacteria as the predominant bacterial hosts of ARGs in pristine environments. We first described the broad diversity of ARG hosts in different environments using metagenome-wide analysis. Our results revealed the heterogeneous distribution of ARGs and their hosts among different microbial niches in gut-associated environments and the pristine environments.
•Gut-associated microbiome had a higher detection rate of ARGs.•Much larger concentration of intrinsical ARGs in pristine environments were found.•ARGs exhibited a positive correlation with anthropogenic impacts.•ARG hosts are not randomly distributed in heterogeneous environments.
Herein we present a new viologen‐based radical‐containing metal–organic framework (RMOF) Gd‐IHEP‐7, which upon heating in air undergoes a single‐crystal‐to‐single‐crystal transformation to generate ...Gd‐IHEP‐8. Both RMOFs exhibit excellent air and water stability as a result of favorable radical‐radical interactions, and their long‐lifetime radicals result in wide spectral absorption in the range 200–2500 nm. Gd‐IHEP‐7 and Gd‐IHEP‐8 show excellent activity toward solar‐driven nitrogen fixation, with ammonia production rates of 128 and 220 μmol h−1 g−1, respectively. Experiments and theoretical calculations indicate that both RMOFs have similar nitrogen fixation pathways. The enhanced catalytic efficiency of Gd‐IHEP‐8 versus Gd‐IHEP‐7 is attributed to intermediates stabilized by enhanced hydrogen bonding.
A single‐crystal‐to‐single‐crystal (SCSC) transformation of stable radical‐containing MOF Gd‐IHEP‐7 generates Gd‐IHEP‐8. It is accompanied by a marked increase in efficiency of sacrificial agent‐free photocatalytic nitrogen fixation to yield NH3 from H2O and N2 under simulated solar light irradiation at ambient temperature. The NH3 production rate of 220 μmol h−1 g−1 for Gd‐IHEP‐8 is a new record for MOF photocatalysts.
Many healthcare workers were infected by coronavirus disease 2019 (COVID-19) early in the epidemic posing a big challenge for epidemic control. Hence, this study aims to explore perceived infection ...routes, influencing factors, psychosocial changes, and management procedures for COVID-19 infected healthcare workers.
This is a cross-sectional, single hospital-based study. We recruited all 105 confirmed COVID-19 healthcare workers in the Zhongnan Hospital of Wuhan University from February 15 to 29, 2020. All participants completed a validated questionnaire. Electronic consent was obtained from all participants. Perceived causes of infection, infection prevention, control knowledge and behaviour, psychological changes, symptoms and treatment were measured.
Finally, 103 professional staff with COVID-19 finished the questionnaire and was included (response rate: 98.1%). Of them, 87 cases (84.5%) thought they were infected in working environment in hospital, one (1.0%) thought their infection was due to the laboratory environment, and 5 (4.9%) thought they were infected in daily life or community environment. Swab of throat collection and physical examination were the procedures perceived as most likely causing their infection by nurses and doctors respectively. Forty-three (41.8%) thought their infection was related to protective equipment, utilization of common equipment (masks and gloves). The top three first symptoms displayed before diagnosis were fever (41.8%), lethargy (33.0%) and muscle aches (30.1%). After diagnosis, 88.3% staff experienced psychological stress or emotional changes during their isolation period, only 11.7% had almost no emotional changes. Arbidol (Umifenovir; an anti-influza drug; 69.2%) was the drug most commonly used to target infection in mild and moderate symptoms.
The main perceived mode of transmission was not maintaining protection when working at a close distance and having intimate contact with infected cases. Positive psychological intervention is necessary.
A
bstract
We study a dark matter model constructed by extending the standard model with an inert SU(2)
L
sextuplet scalar of hypercharge 1/2. The sextuplet components are split by the quartic ...couplings between the sextuplet and the Higgs doublet after electroweak symmetry breaking, resulting in a dark sector with one triply charged, two doubly charged, two singly charged, and two neutral scalars. The lighter neutral scalar boson acts as a dark matter particle. We investigate the constraints on this model from the monojet +
and soft-dilepton + jets +
searches at the 13 TeV Large Hadron Collider, as well as from the current electroweak precision test. Furthermore, we estimate the projected sensitivities of a 100 TeV
pp
collider and of a future
e
+
e
−
collider, and find that such future projects could probe TeV mass scales. Nonetheless, such mass scales only correspond to a subdominant component of the observed relic abundance if the dark matter particles solely originate from thermal production.
Vector-like quarks arise in many new theories beyond the Standard Model, which is driven by several theoretical issues. In a framework of the Standard Model simply extended by an SU(2) singlet ...vector-like bottom quark, we present a study of single production of such vector-like bottom quark at the LHeC. The work is preformed with assuming the LHeC with center of mass energy s=1.98 TeV and an integrated luminosity L=1000fb−1. We focus on the process e−p→νeB→νebH(orZ)→νebbb¯. The signal is searched in events with three b-jets within final state. Exclusion (discover) capability of the LHeC for the signal of the vector-like bottom quark are obtained at 2 σ (5 σ) confidence level. Our result demonstrates a significant improvement compared to previous relevant researches. We also discuss the capability of LHeC for the singlet B search with combined analysis from other experiments.
MicroRNA‐142‐3p (miR‐142‐3p) was previously investigated in various cancers, whereas, it's role in breast cancer (BC) remains far from understood. In this study, we found that miR‐142‐3p was markedly ...decreased both in cell lines and BC tumor tissues. Elevated miR‐142‐3p expression suppressed growth and metastasis of BC cell lines via gain‐of‐function assay in vitro and in vivo. Mechanistically, miR‐142‐3p could regulate the ras‐related C3 botulinum toxin substrate 1 (RAC1) expression in protein level, which simultaneously suppressed the epithelial‐to‐mesenchymal transition related protein levels and the activity of PAK1 phosphorylation, respectively. In addition, rescue experiments revealed RAC1 overexpression could reverse tumor‐suppressive role of miR‐142‐3p. Our results showed miR‐142‐3p could function as a tumor suppressor via targeting RAC1/PAK1 pathway in BC, suggesting a potent therapeutic target for BC treatment.
MiR‐142‐3p is downregulated in breast cancer (BC) tissues and cell lines. MiR‐142‐3p may act as a tumor suppressor by regulating cell proliferation, migration, invasion, angiogenesis, and epithelial‐to‐mesenchymal transition process through directly downregulation of ras‐related C3 botulinum toxin substrate 1 expression and subsequently inhibiting the activity of PAK1 phosphorylation in BC.
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