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"Lu, Meng"
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Detection of Novel Coronavirus by RT-PCR in Stool Specimen from Asymptomatic Child, China
We report an asymptomatic child who was positive for a coronavirus by reverse transcription PCR in a stool specimen 17 days after the last virus exposure. The child was virus positive in stool specimens for at least an additional 9 days. Respiratory tract specimens were negative by reverse transcription PCR.
Journal Article
Two-particle scattering from finite-volume quantization conditions using the plane wave basis
A
bstract
We propose an alternative approach to Lüscher’s formula for extracting two-body scattering phase shifts from finite volume spectra with no reliance on the partial wave expansion. We use an effective-field-theory-based Hamiltonian method in the plane wave basis and decompose the corresponding matrix elements of operators into irreducible representations of the relevant point groups. The proposed approach allows one to benefit from the knowledge of the long-range interaction and avoids complications from partial wave mixing in a finite volume. We consider spin-singlet channels in the two-nucleon system and pion-pion scattering in the
ρ
-meson channel in the rest and moving frames to illustrate the method for non-relativistic and relativistic systems, respectively. For the two-nucleon system, the long-range interaction due to the one-pion exchange is found to make the single-channel Lüscher formula unreliable at the physical pion mass. For S-wave dominated states, the single-channel Lüscher method suffers from significant finite-volume artifacts for a
L
= 3 fm box, but it works well for boxes with
L >
5 fm. However, for P-wave dominated states, significant partial wave mixing effects prevent the application of the single-channel Lüscher formula regardless of the box size (except for the near-threshold region). Using a toy model to generate synthetic data for finite-volume energies, we show that our effective-field-theory-based approach in the plane wave basis is capable of a reliable extraction of the phase shifts. For pion-pion scattering, we employ a phenomenological model to fit lattice QCD results at the physical pion mass. The extracted P-wave phase shifts are found to be in a good agreement with the experimental results.
Journal Article
Hidden-charm and hidden-bottom molecular pentaquarks in chiral effective field theory
A
bstract
The newly observed
P
c
(4312),
P
c
(4440) and
P
c
(4457) at the LHCb experiment are very close to the
Σ
c
D
¯
and
Σ
c
D
¯
∗
thresholds. In this work, we perform a systematic study and give a complete picture on the interactions between the
Σ
c
∗
and
D
¯
∗
systems in the framework of heavy hadron chiral effective field theory, where the short-range contact interaction, long-range one-pion-exchange contribution, and intermediate-range two-pion-exchange loop diagrams are all considered. We first investigate the three
Pc
states without and with considering the Λ
c
contribution in the loop diagrams. It is difficult to simultaneously reproduce the three
P
c
s unless the Λ
c
is included. The coupling between the
Σ
c
∗
D
¯
∗
and
Λ
c
D
¯
∗
channels is crucial for the formation of these
P
c
s. Our calculation supports the
P
c
(4312),
P
c
(4440) and
P
c
(4457) to be the
S
-wave hidden-charm
Σ
c
D
¯
J
=
1
/
2
I
=
1
/
2
,
Σ
c
D
¯
∗
J
=
1
/
2
I
=
1
/
2
and
Σ
c
D
¯
∗
J
=
3
/
2
I
=
1
/
2
molecular pentaquarks, respectively. Our calculation disfavors the spin assignment
J
P
=
1
−
2
for
P
c
(4457) and
J
P
=
3
−
2
for
P
c
(4440), because the excessively enhanced spin-spin interaction is unreasonable in the present case. We obtain the complete mass spectra of the
Σ
c
∗
D
¯
∗
J
systems with the fixed low energy constants. Our result indicates the existence of the
Σ
c
∗
D
¯
∗
J
J
=
1
2
3
2
5
2
hadronic molecules. The previously reported
P
c
(4380) might be a deeper bound one. Additionally, we also study the hidden-bottom
Σ
b
∗
B
∗
systems, and predict seven bound molecular states, which could serve as a guidance for future experiments. Furthermore, we also examine the heavy quark symmetry breaking effect in the hidden-charm and hidden-bottom systems by taking into account the mass splittings in the propagators of the intermediate states. As expected, the heavy quark symmetry in the bottom cases is better than that in the charmed sectors. We notice that the heavy quark symmetry in the
Σ
c
D
¯
and
Σ
c
∗
D
¯
systems is much worse for some fortuitous reasons. The heavy quark symmetry breaking effect is nonnegligible in predicting the effective potentials between the charmed hadrons.
Journal Article
Antibacterial and biodegradable tissue nano-adhesives for rapid wound closure
Although various organic tissue adhesives designed to facilitate would healing are gaining popularity in diverse clinical applications, they present significant inherent limitations, such as rejection, infections, toxicity and/or excessive swelling. It is highly desirable to develop efficient, biocompatible and anti-bacterial tissue adhesives for skin wound healing.
Inspired by the fact that inorganic nanoparticles can directly glue tissues through the \"nanobridging effect\", herein disulfide bond-bridged nanosilver-decorated mesoporous silica nanoparticles (Ag-MSNs) was constructed as an effective and safe tissue adhesive with antibacterial and degradable properties for wound closure and healing.
Ag-MSNs was fabricated by controlled reduce of ultrasmall nanosilvers onto the both surface and large pore of biodegradable MSNs. The obtained MSNs were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and measurement of size distribution, zeta potential, and mesopore properties. Furthermore, adhesion strength test, anti-bacterial assessment, mouse skin wound model, and MTT assays were used to investigate the tissue adhesive property, antibacterial effect, biodegradability and biocompatibility of the Ag-MSNs.
Ag-MSNs exhibited not only strong adhesive properties but also excellent antibacterial activities than that of MSNs. Importantly, this antibacterial nano-adhesive achieved rapid and efficient closure and healing of wounds in comparison to sutures or MSNs in a mouse skin wound model. Furthermore, Ag-MSNs with fast degradable behavior caused little cellular toxicity and even less systemic toxicity during wound healing.
Our findings suggest that biodegradable Ag-MSNs can be employed as the next generation of nano-adhesives for rapid wound closure and aesthetic wound healing.
Journal Article
Redox/pH dual-controlled release of chlorhexidine and silver ions from biodegradable mesoporous silica nanoparticles against oral biofilms
Oral plaque biofilms pose a threat to periodontal health and are challenging to eradicate. There is a growing belief that a combination of silver nanoparticles and chlorhexidine (CHX) is a promising strategy against oral biofilms.
To overcome the side effects of this strategy and to exert maximum efficiency, we fabricated biodegradable disulfide-bridged mesoporous silica nanoparticles (MSNs) to co-deliver silver nanoparticles and CHX for biofilm inhibition.
CHX-loaded, silver-decorated mesoporous silica nanoparticles (Ag-MSNs@CHX) were fabricated after CHX loading, and the pH- and glutathione-responsive release profiles of CHX and silver ions along with their mechanism of degradation were systematically investigated. Then, the efficacy of Ag-MSNs@CHX against
and its biofilm was comprehensively assessed by determining the minimum inhibitory concentration, minimum bactericidal concentration, minimal biofilm inhibitory concentration, and the inhibitory effect on
biofilm formation. In addition, the biosafety of nanocarriers was evaluated by oral epithelial cells and a mouse model.
The obtained Ag-MSNs@CHX possessed redox/pH-responsive release properties of CHX and silver ions, which may be attributed to the redox-triggered matrix degradation mechanism of exposure to biofilm-mimetic microenvironments. Ag-MSNs@CHX displayed dose-dependent antibacterial activity against planktonic and clone formation of
. Importantly, Ag-MSNs@CHX had an increased and long-term ability to restrict the growth of
biofilms compared to free CHX. Moreover, Ag-MSNs@CHX showed less cytotoxicity to oral epithelial cells, whereas orally administered Ag-MSNs exhibited no obvious toxic effects in mice.
Our findings constitute a highly effective and safe strategy against biofilms that has a good potential as an oral biofilm therapy.
Journal Article
NPM1 Is a Prognostic Biomarker Involved in Immune Infiltration of Lung Adenocarcinoma and Associated With m6A Modification and Glycolysis
Overexpression of NPM1 can promote the growth and proliferation of various tumor cells. However, there are few studies on the comprehensive analysis of NPM1 in lung adenocarcinoma (LUAD).
TCGA and GEO data sets were used to analyze the expression of NPM1 in LUAD and clinicopathological analysis. The GO/KEGG enrichment analysis of NPM1 co-expression and gene set enrichment analysis (GSEA) were performed using R software package. The relationship between NPM1 expression and LUAD immune infiltration was analyzed using TIMER, GEPIA database and TCGA data sets, and the relationship between NPM1 expression level and LUAD m6A modification and glycolysis was analyzed using TCGA and GEO data sets.
NPM1 was overexpressed in a variety of tumors including LUAD, and the ROC curve showed that NPM1 had a certain accuracy in predicting the outcome of tumors and normal samples. The expression level of NPM1 in LUAD is significantly related to tumor stage and prognosis. The GO/KEGG enrichment analysis indicated that NPM1 was closely related to translational initiation, ribosome, structural constituent of ribosome, ribosome, Parkinson disease, and RNA transport. GSEA showed that the main enrichment pathway of NPM1-related differential genes was mainly related to mTORC1 mediated signaling, p53 hypoxia pathway, signaling by EGFR in cancer, antigen activates B cell receptor BCR leading to generation of second messengers, aerobic glycolysis and methylation pathways. The analysis of TIMER, GEPIA database and TCGA data sets showed that the expression level of NPM1 was negatively correlated with B cells and NK cells. The TCGA and GEO data sets analysis indicated that the NPM1 expression was significantly correlated with one m6A modifier related gene (YTHDF2) and five glycolysis related genes (ENO1, HK2, LDHA, LDHB and SLC2A1).
NPM1 is a prognostic biomarker involved in immune infiltration of LUAD and associated with m6A modification and glycolysis. NPM1 can be used as an effective target for diagnosis and treatment of LUAD.
Journal Article
The Compromised Intestinal Barrier Induced by Mycotoxins
Mycotoxins are fungal metabolites that occur in human foods and animal feeds, potentially threatening human and animal health. The intestine is considered as the first barrier against these external contaminants, and it consists of interconnected physical, chemical, immunological, and microbial barriers. In this context, based on in vitro, ex vivo, and in vivo models, we summarize the literature for compromised intestinal barrier issues caused by various mycotoxins, and we reviewed events related to disrupted intestinal integrity (physical barrier), thinned mucus layer (chemical barrier), imbalanced inflammatory factors (immunological barrier), and dysfunctional bacterial homeostasis (microbial barrier). We also provide important information on deoxynivalenol, a leading mycotoxin implicated in intestinal dysfunction, and other adverse intestinal effects induced by other mycotoxins, including aflatoxins and ochratoxin A. In addition, intestinal perturbations caused by mycotoxins may also contribute to the development of mycotoxicosis, including human chronic intestinal inflammatory diseases. Therefore, we provide a clear understanding of compromised intestinal barrier induced by mycotoxins, with a view to potentially develop innovative strategies to prevent and treat mycotoxicosis. In addition, because of increased combinatorial interactions between mycotoxins, we explore the interactive effects of multiple mycotoxins in this review.
Journal Article
PagWOX11/12a activates PagCYP736A12 gene that facilitates salt tolerance in poplar
Summary The WUSCHEL‐related homeobox (WOX) transcription factors WOX11 and WOX12 regulate adventitious rooting and responses to stress. The underlying physiological and molecular regulatory mechanisms in salt stress tolerance remain largely unexplored. Here, we characterized the roles of PagWOX11/12a from 84K poplar (Populus alba × P. glandulosa) and the underlying regulatory mechanism in salt stress. PagWOX11/12a was strongly induced by salt stress in roots. Overexpression of PagWOX11/12a in poplar enhanced salt tolerance, as evident by the promotion of growth‐related biomass. In contrast, salt‐treated PagWOX11/12a dominant repression plants displayed reduced biomass growth. Under salt stress conditions, PagWOX11/12a‐overexpressed lines showed higher reactive oxygen species (ROS) scavenging capacity and lower accumulation of hydrogen peroxide (H2O2) than non‐transgenic 84K plants, whereas the suppressors displayed the opposite phenotype. In addition, PagWOX11/12a directly bound to the promoter region of PagCYP736A12 and regulated PagCYP736A12 expression. The activated PagCYP736A12 could enhance ROS scavenging, thus reducing H2O2 levels in roots under salt stress in PagWOX11/12a‐overexpressed poplars. The collective results support the important role of PagWOX11/12a in salt acclimation of poplar trees, indicating that PagWOX11/12a enhances salt tolerance through modulation of ROS scavenging by directly regulating PagCYP736A12 expression in poplar.
Journal Article