Creating oxide interfaces with precise chemical specificity at the atomic layer level is desired for the engineering of quantum phases and electronic applications, but highly challenging, owing ...partially to the lack of in situ tools to monitor the chemical composition and completeness of the surface layer during growth. Here we report the in situ observation of atomic layer-by-layer inner potential variations by analysing the Kikuchi lines during epitaxial growth of strontium titanate, providing a powerful real-time technique to monitor and control the chemical composition during growth. A model combining the effects of mean inner potential and step edge density (roughness) reveals the underlying mechanism of the complex and previously not well-understood reflection high-energy electron diffraction oscillations observed in the shuttered growth of oxide films. General rules are proposed to guide the synthesis of atomically and chemically sharp oxide interfaces, opening up vast opportunities for the exploration of intriguing quantum phenomena at oxide interfaces.
Abstract
We report on a detailed spectral analysis of the transient X-ray pulsar 1A 0535+262, which underwent the brightest giant outburst ever recorded for this source from 2020 November to December ...with a peak luminosity of 1.2 × 10
38
erg s
−1
. Thanks to the unprecedented energy coverage and high-cadence observations provided by Insight-HXMT, we were able to find for the first time evidence for a transition of the accretion regime. At high luminosity, above the critical luminosity 6.7 × 10
37
erg s
−1
, the cyclotron absorption line energy anticorrelates with luminosity. Below the critical luminosity, a positive correlation is observed. Therefore, 1A 0535+262 becomes the second source after V0332+53, which clearly shows an anticorrelation above and transition between correlation and anticorrelation around the critical luminosity. The evolution of both the observed CRSF line energy and broadband X-ray continuum spectrum throughout the outburst exhibits significant differences during the rising and fading phases; that is, for a similar luminosity, the spectral parameters take different values, which results in hysteresis patterns for several spectral parameters including the cyclotron line energy. We argue that, similar to V0332+53, these changes might be related to the different geometry of the emission region in rising and declining parts of the outburst, probably due to changes in the accretion disk structure and its interaction with the magnetosphere of the neutron star.
Non-small cell lung cancer (NSCLC) is the leading cause of cancer death, reflecting the need for better understanding the oncogenesis, and developing new diagnostic and therapeutic targets for the ...malignancy. Emerging evidence suggests that small nucleolar RNAs (snoRNAs) have malfunctioning roles in tumorigenesis. Our recent study demonstrated that small nucleolar RNA 42 (SNORA42) was overexpressed in lung tumors. Here, we investigate the role of SNORA42 in tumorigenesis of NSCLC. We simultaneously assess genomic dosages and expression levels of SNORA42 and its host gene, KIAA0907, in 10 NSCLC cell lines and a human bronchial epithelial cell line. We then determine in vitro functional significance of SNORA42 in lung cancer cell lines through gain- and loss-of-function analyses. We also inoculate cancer cells with SNORA42-siRNA into mice through either tail vein or subcutaneous injection. We finally evaluate expression level of SNORA42 on frozen surgically resected lung tumor tissues of 64 patients with stage I NSCLC by using quantitative reverse transcriptase PCR assay. Genomic amplification and associated high expression of SNORA42 rather than KIAA0907 are frequently observed in lung cancer cells, suggesting that SNORA42 overexpression is activated by its genomic amplification. SNORA42 knockdown in NSCLC cells inhibits in vitro and in vivo tumorigenicity, whereas enforced SNORA42 expression in bronchial epitheliums increases cell growth and colony formation. Such pleiotropy of SNORA42 suppression could be achieved at least partially through increased apoptosis of NSCLC cells in a p53-dependent manner. SNORA42 expression in lung tumor tissue specimens is inversely correlated with survival of NSCLC patients. Therefore, SNORA42 activation could have an oncogenic role in lung tumorigenesis and provide potential diagnostic and therapeutic targets for the malignancy.
While most NOD‐like receptors (NLRs) are predominately expressed by innate immune cells, NLRC3, an inhibitory NLR of immune signaling, exhibits the highest expression in lymphocytes. The role of ...NLRC3 or any NLRs in B lymphocytes is completely unknown. Gammaherpesviruses, including human Epstein–Barr virus (EBV) and murine gammaherpesvirus 68 (MHV‐68), establish latent infection in B lymphocytes, which requires elevated NF‐κB. This study shows that during latent EBV infection of human B cells, viral‐encoded latent membrane protein 1 (LMP1) decreases NLRC3 transcript. LMP1‐induced‐NF‐κB activation suppresses the promoter activity of NLRC3 via p65 binding to the promoter. Conversely, NLRC3 inhibits NF‐κB activation by promoting the degradation of LMP1 in a proteasome‐dependent manner. In vivo, MHV‐68 infection reduces Nlrc3 transcripts in splenocytes, and Nlrc3‐deficient mice show greater viral latency than controls. These results reveal a bidirectional regulatory circuit in B lymphocytes, where viral latent protein LMP1 reduces NLRC3 expression, while NLRC3 disrupts gammaherpesvirus latency, which is an important step for tumorigenesis.
This study was conducted to investigate the effects of pyrroloquinoline quinone disodium (PQQ·Na2) on inflammatory responses, oxidative stress, and intestinal morphology of broiler chickens ...challenged with lipopolysaccharide (LPS). A 2 × 2 factorial arrangement in a complete randomized design experiment was used to study the effect of dietary PQQ·Na2 (0 or 1 mg/kg) on broiler chickens with or without a challenge with LPS. A total of two hundred eighty-eight 1-day-old Arbor Acre broiler chickens were randomly assigned to 4 treatments with 6 replicate cages of 12 birds per cage. All experimental broilers were injected intraperitoneally with 0.5 mg/kg body weight of either Escherichia coli LPS or sterile saline at 16, 18, and 20 d of age. Results showed that injecting LPS significantly increased the concentrations of interleukin-1beta (IL-1β) in serum of birds on day 20 and day 21. Meanwhile, LPS injection increased (P < 0.05) the relative mRNA expression of interleukin-6 (IL-6) in the duodenal mucosa of broilers on day 21. However, dietary supplementation with PQQ·Na2 decreased (P < 0.05) the concentration of IL-6 in serum of birds on day 20 and the levels of IL-1β, IL-6, and interleukin-10 (IL-10) in serum of broiler chickens on day 21. Besides, supplementation of PQQ·Na2 within diet decreased (P < 0.05) the mRNA expressions of IL-1β and IL-10 in the duodenal mucosa of birds on day 20. Relative to saline injection, the activity of glutathione peroxidase (GSH-Px) in serum and the activities of total superoxide dismutase (T-SOD) and catalase (CAT) in liver were found to be lower (P < 0.05) in broilers after LPS challenge on day 21. However, birds fed with PQQ·Na2 showed higher (P < 0.05) GSH-Px activity in serum and higher (P < 0.05) T-SOD activities in liver on day 21 and day 42. Pyrroloquinoline quinone disodium also significantly attenuated the LPS-induced decreases in villus height to crypt depth ratio in the duodenum of broilers. In conclusion, dietary PQQ·Na2 supplementation significantly exerted protective effects on inflammation damage and oxidant stress of broilers under LPS challenge by regulating the expression of inflammatory cytokines (IL-1β, IL-6, and IL-10) and activities of antioxidant enzymes (GSH-Px, T-SOD, and CAT). Moreover, dietary PQQ·Na2 supplementation significantly ameliorated the LPS-impaired intestinal morphology in broilers. Therefore, it has been considered that PQQ·Na2 can be used as a potential feed additive in broiler production.
AIMS: Wheat straw is generated in billions of tons around the world every year and has not been fully used. This study sought to evaluate the delignification capacity and enzyme production of ...Trametes trogii MT strain and to clarify the changes of structure and chemical composition of wheat straw during the decay process. METHODS AND RESULTS: The results obtained revealed that the T. trogii MT strain has the ability to degrade lignin, cellulose as well as hemicellulose of wheat straw simultaneously. The strain can produce high activities of laccase, manganese peroxidase, xylanase, carboxymethylcellulase and feruloyl esterase but no lignin peroxidases during the decay process of a 60‐day incubation period on wheat straw. Scanning electron microscopy observation and infrared spectroscopy analysis showed the lignin and carbohydrate of wheat straw were degraded with no obvious different levels. The low molecular mass fractions collected from the culture of the MT strains grown in wheat straw powder liquid medium showed high Fe³⁺chelating, reducing capacity and hydroxyl radical and hydrogen peroxide generation. CONCLUSIONS: Trametes trogii MT has a complex mechanism to degrade lignocellulose, in addition to the extracellular enzymatic systems, and has great potential as an attractive micro‐organism used for the biological degradation of waste straws. SIGNIFICANCE AND IMPACT OF THE STUDY: This study revealed the dynamic changes of the ligninolytic enzymes of T. trogii MT during the degradation of wheat straw, and suggested that the decay patterns of wheat straw by T. trogii MT had some simultaneous type characteristics.
A
bstract
Using (10087 ± 44) × 10
6
J
/
ψ
events collected with the BESIII detector at the BEPCII
e
+
e
−
storage ring at the center-of-mass energy of
s
= 3.097 GeV, we present a search for the rare ...semi-muonic charmonium decay
J
/
ψ
→
D
−
μ
+
ν
μ
+ c.c.. Since no significant signal is observed, we set an upper limit of the branching fraction to be
B
(
J
/
ψ
→
D
−
μ
+
ν
μ
+ c.c.) < 5.6 × 10
−
7
at 90% confidence level. This is the first search for the weak decay of charmonium with a muon in the final state.
A
bstract
Based on
e
+
e
−
collision data collected at center-of-mass energies from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a partial wave analysis is performed for the ...process
e
+
e
−
→
K
S
0
K
L
0
π
0
. The results allow the Born cross sections of the process
e
+
e
−
→
K
S
0
K
L
0
π
0
, as well as its subprocesses
e
+
e
−
→
K
∗
(892)
0
K
¯
0
and
K
2
∗
(1430)
0
K
¯
0
to be measured. The Born cross sections for
e
+
e
−
→
K
S
0
K
L
0
π
0
are consistent with previous measurements by BaBar, but with substantially improved precision. The Born cross section lineshape of the process
e
+
e
−
K
∗
(892)
0
K
¯
0
is consistent with a vector meson state around 2.2 GeV with a significance of 3.2
σ
. A Breit-Wigner fit determines its mass as
M
Y
= (2164
.
7
±
9
.
1
±
3
.
1) MeV
/c
2
and its width as Γ
Y
= (32
.
4
±
21
.
0
±
1
.
8) MeV.
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