A
bstract
In this paper, we calculate the matrix element and form factors of vector-to- vector (
V
I
→ V
II
) transition within the standard light-front (SLF) and covariant light- front (CLF) quark ...models (QMs), and investigate the self-consistency and Lorentz covari- ance of the CLF QM within two types of correspondences between the manifest covariant Bethe-Salpeter approach and the LF approach. The zero-mode and valence contributions to the form factors of
V
I
→ V
II
transition in the CLF QM and their relation to the SLF results are analyzed, and the main conclusions obtained via the decay constants of vector and axial-vector mesons and the form factors of
P → V
transition in the previous works are confirmed again. Furthermore, we present our numerical predictions for the form factors of
c →
(
q, s
) (
q
=
u, d
) induced
D
*
→
(
K
*
, ρ
),
D
∗
→
(
ϕ, K
*
),
J/
Ψ
→
D
s
∗
D
∗
,
B
c
∗
→
B
s
∗
B
∗
transitions and
b →
(
c, s, q
) induced
B
∗
→ (
D
∗
,
K
∗
,
ρ
),
B
s
∗
→
D
s
∗
ϕ
K
∗
,
B
c
∗
→
J
/
Ψ
D
s
∗
D
∗
,
ϒ
1
S
→
B
c
∗
B
s
∗
B
∗
the relevant phenomenological studies of meson decays.
Press-hardened steels (PHS) with a 1.5-mm-thick coated Al⁻Si layer is welded using an IPG YLS6000 continuous fiber laser in the air atmosphere. An SU5000 scanning electron microscope (SEM) and an ...Oxford EDS X-Max20 energy spectrometer are used to characterize the microstructure, which consists of delta (δ)-ferrite and lath martensite. It is similar to that of the welding performed in the Ar atmosphere, but the content of δ-ferrite is less. The reason is the formation of Al₂O₃ inclusions in the molten pool, which reacts with oxygen from the air ambient and the Al from the molten Al⁻Si coating of PHS. The oxygen content is measured with an ONH-3000 analyzer. An HV-1000 microhardness tester and DNS-100 universal material test equipment are performed to test the hardness and tensile strength. Similar hardness and strength of welded joints are achieved welding in the air atmosphere compared to that of the Ar atmosphere. Fracture was initialed in the fusion line of overlapping zone and propagated along the interface of two plates and fusion line due to the Al segregation.
The pursuit of single-molecule magnets (SMMs) with better performance urges new molecular design that can endow SMMs larger magnetic anisotropy. Here we report that two-coordinate cobalt imido ...complexes featuring highly covalent CoN cores exhibit slow relaxation of magnetization under zero direct-current field with a high effective relaxation barrier up to 413 cm–1, a new record for transition metal based SMMs. Two theoretical models were carried out to investigate the anisotropy of these complexes: single-ion model and Co–N coupling model. The former indicates that the pseudo linear ligand field helps to preserve the first-order orbital momentum, while the latter suggests that the strong ferromagnetic interaction between Co and N makes the CoN+ fragment a pseudo single paramagnetic ion, and that the excellent performance of these cobalt imido SMMs is attributed to the inherent large magnetic anisotropy of the CoN+ core with |M J = ± 7/2⟩ ground Kramers doublet.
Cell-free DNA is naturally degraded in various bodily fluids. The aim of this study was to determine the degradation kinetics of DNA, with and without protein, in serum, urine and saliva.
Naked DNA ...and DNA-protein complex were prepared, added to the samples to be analysed and incubated at 37°C and room temperature for various lengths of time. Alleles of 20 short tandem repeat loci were amplified from the incubated samples, and clearance models were generated from the mean peak areas.
Plotting the natural logarithm of DNA concentration against the incubation time produced a linear relationship. The half-lives of DNA with and without protein in serum were 157.6min and 30.8min at 37°C, 330.5min and 70.5min at room temperature, respectively. The half-lives of DNA with protein in saliva were 175.6min and 251.3min at 37°C and room temperature, respectively. However, the half-lives of DNA in urine (both with and without protein) were too short to detect.
The kinetics of DNA degradation in serum and saliva followed a first-order clearance model. Urine had the strongest effect on DNA degradation, and the half-lives of DNA with protein were relatively longer than those of naked DNA.
•DNA degradations were qualitatively observed in serum, saliva and urine.•DNA degradation followed a first-order clearance model in these samples.•The half-lives of DNA with protein were relatively longer than those of naked DNA.•The half-lives were around 3h in 37°C and 5h in 24°C for serum and saliva.•The half-lives of DNA in urine were too short to detect in room temperature.
X-linked inhibitor of apoptosis protein (XIAP) possesses a critical role in promotion of cell survival and maintenance of cellular homeostasis. In cancer, elevated XIAP expression has been associated ...with malignancy, poor prognosis, and treatment resistance. However, the underlying mechanisms of these effects remain unclear. XIAP has previously been proposed to promote tumor growth through suppression of autophagy. In this study, we examined the expression of XIAP and p62, two critical mediators of autophagy, in breast and colon cancer. We observed a negative correlation between XIAP and p62 expression in normal and cancer tissues of breast and colon, and that the ratio of XIAP and p62 expression determines the cancer phenotype. In vitro, we observed that XIAP interacted with p62 and also that XIAP depletion resulted in increased expression of p62. XIAP functioned as an ubiquitination E3 ligase towards p62 and suppressed p62 expression through ubiquitin-proteasomal degradation. Furthermore, XIAP enhanced cancer cell proliferation, viability, and colony formation in vitro via suppression of p62. In addition, we demonstrated that XIAP-enhanced tumor growth is dependent on depletion of p62 in vivo. Herein, we have therefore delineated a novel mechanism by which XIAP contributes to development and progression of breast and colon carcinoma.
Both phototropins (phot1 and phot2) and cryptochromes (cry1 and cry2) were proven as the Arabidopsis thaliana blue light receptors. Phototropins predominately function in photomovement, and ...cryptochromes play a role in photomorphogenesis. Although cryptochromes have been proposed to serve as positive modulators of phototropic responses, the underlying mechanism remains unknown. Here, we report that depleting sucrose from the medium or adding gibberellic acids (GAs) can partially restore the defects in phototropic curvature of the phot1 phot2 double mutants under high‐intensity blue light; this restoration does not occur in phot1 phot2 cry1 cry2 quadruple mutants and nph3 (nonphototropic hypocotyl 3) mutants which were impaired phototropic response in sucrose‐containing medium. These results indicate that GAs and sucrose antagonistically regulate hypocotyl phototropism in a cryptochromes dependent manner, but it showed a crosstalk with phototropin signaling on NPH3. Furthermore, cryptochromes activation by blue light inhibit GAs synthesis, thus stabilizing DELLAs to block hypocotyl growth, which result in the higher GAs content in the shade side than the lit side of hypocotyl to support the asymmetric growth of hypocotyl. Through modulation of the abundance of DELLAs by sucrose depletion or added GAs, it revealed that cryptochromes have a function in mediating phototropic curvature.
The concluded function of cryptochromes in hypocotyls phototropism is controversial. By phenotypic analysis of mutant lines grown on sucrose free medium or medium with added gibberellic acids, we demonstrated that cryptochromes‐mediated hypocotyl phototropism was regulated antagonistically by gibberellin and sugar. This process showed a crosstalk with phototropin signaling on NPH3.
A hydroxide-template strategy coupled with in-situ chemical activation is reported for the first time to fabricate porous carbon nanosheets (PCNSs) from coal tar. The thin PCNSs feature abundant ...short pores accessible for fast ion transport and high specific surface area up to 3235 m2 g−1 for ion adsorption. As electrodes for supercapacitors, the PCNSs show a high capacitance of 296.2 F g−1 at 0.05 A g−1 in 6 M KOH electrolyte, an excellent rate performance with a capacitance of 220.7 F g−1 at 20 A g−1 and a superior cycle stability with over 97.2% capacitance retention after 11000 charge-discharge cycles at 3.5 A g−1. This work paves a new way for efficient fabrication of sheet-like carbon materials with tuned porous structure from polycyclic aromatic hydrocarbons for high performance supercapacitors.
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•A hydroxide-template method was developed to prepare porous carbon nanosheets.•Porous carbon nanosheets feature short hierarchical pores and high surface area.•Porous carbon nanosheet electrodes show high capacitance and good cycle stability.
800MPa strength cold rolled annealed DP steels was welded by different heat inputs (6–66J/mm) using 6kW fiber laser, to study the microstructure and fracture behavior of laser welded joints with ...sub-micron scale soften zone. The microstructure and fracture morphology of welded joints were observed by scanning electron microscope (SEM) and optical microscope (OM). Hardness, tensile properties and formability of welded joints were tested using microhardness tester, universal material testing equipment and Erichsen test machine. The results showed that the microstructure of welded joints was similar, but decomposition of martensite and precipitation of carbides was significant gradually with heat input increased such that the hardness was decreased. For the complete penetration of DP780 laser welded joints, the soften zone was impossible to eliminate by adjusting the heat input. When the size of soften zone was controlled within 539µm, the tensile properties and formability of welded joints were more than 95% of BM, due to the double effect of the size and microstructure of soften zone.
A high-performance potassium-ion battery anode is achieved by using nitrogen-doped soft carbon frameworks with high electronic and ionic conductivity.
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•N-doped soft carbon frameworks ...have been fabricated by MgO template method.•The N-doped soft carbon shows rapid electron transfer and K+ diffusion.•The N-doped soft carbon anode presents a superior rate performance and ultra-stable cycle life.•The ordered N-doped carbon clusters with enlarged interlayer distance may responsible for the superior rate performance.
Potassium-ion batteries (PIBs) have been regarded as one of the most promising alternatives to traditional lithium-ion batteries because of the low cost and abundant reserves of potassium resources. However, it is challenging to achieve suitable anode materials with long cycle life and high rate performance. Herein, nitrogen-doped soft carbon frameworks built of well-interconnected nanocapsules have been fabricated as facile and effective anodes for PIBs. The anode delivers a high specific capacity of 293 mAh g−1 at 0.05 A g−1 and 151 mAh g−1 at 5 A g−1 with a rate capability of 51.5%. It retains 85.5% capacity retention at 1 A g−1 after 500 cycles. The excellent rate performance can be mainly ascribed to the high ionic and electronic conductivity, resulted from the ordered nitrogen-doped carbon clusters with enlarged interlayer distance. The interconnected hierarchically porous structure further promotes K+ diffusion kinetics.
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