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.
The World Health Organization has declared the outbreak of a novel coronavirus (SARS-CoV-2 or 2019-nCoV) as a global pandemic. However, the mechanisms behind the coronavirus infection are not yet ...fully understood, nor are there any targeted treatments or vaccines. In this study, we identified high-binding-affinity aptamers targeting SARS-CoV-2 RBD, using an ACE2 competition-based aptamer selection strategy and a machine learning screening algorithm. The K d values of the optimized CoV2-RBD-1C and CoV2-RBD-4C aptamers against RBD were 5.8 nM and 19.9 nM, respectively. Simulated interaction modeling, along with competitive experiments, suggests that two aptamers may have partially identical binding sites at ACE2 on SARS-CoV-2 RBD. These aptamers present an opportunity for generating new probes for recognition of SARS-CoV-2 and could provide assistance in the diagnosis and treatment of SARS-CoV-2 while providing a new tool for in-depth study of the mechanisms behind the coronavirus infection.
Radical trifluoromethylation Xiao, Haiwen; Zhang, Zhenzhen; Fang, Yewen ...
Chemical Society reviews,
06/2021, Letnik:
5, Številka:
11
Journal Article
Recenzirano
The trifluoromethyl group plays an increasingly important role in pharmaceuticals, agrochemicals and materials. This tutorial describes recent advances in trifluoromethylation of carbon-centered ...radical intermediates.
Radical trifluoromethylation has been emerging as a versatile tool for the synthesis of trifluoromethylated compounds that play increasingly important roles in pharmaceuticals, agrochemicals and materials science.
Circular RNA (circRNA) is a novel class of noncoding RNAs with functions in various pathophysiological activities. However, the expression profiles and functions of circRNAs in colorectal cancer ...(CRC) remain largely unknown.
High-throughput RNA sequencing (RNA-seq) was performed to assess circRNA expression profiles in 4 paired CRC tissues, and significantly dysregulated circRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to predict the potential functions of dysregulated circRNAs. Target miRNAs of circRNAs were predicted using miRanda software, and were further analyzed combining DIANA-miRPath v.3 platform (Reverse Search module) with KEGG pathways of COLORECTAL CANCER and MicroRNAs in cancer (Entry: map05210 and map05206). CircRNA-miRNA interaction networks were constructed using Cytoscape software. Expression levels of a significantly down-regulated circRNA, circDDX17 (hsa_circ_0002211), was detected by qRT-PCR in 60 paired CRC tissues. CircDDX17 was knockdown by siRNA, and the biological functions of circDDX17 were examined in CRC cell lines.
Totally 448 differentially expressed circRNAs were identified, including 394 up-regulated and 54 down-regulated circRNAs. qRT-PCR validation confirmed the reliability of the RNA-Seq data. GO and KEGG analyses revealed that these dysregulated circRNAs were potentially implicated in CRC pathogenesis. Analyses by combining miRanda and miRPath softwares with KEGG pathways suggested that the miRNAs targeted by the top 10 dysregulated circRNAs were associated with the KEGG pathways of COLORECTAL CANCER and MicroRNAs in cancer, indicating that circRNA-miRNA interactions might play important functional roles in the initiation and progression of CRC. The results of qRT-PCR for circDDX17 in 60 paired CRC tissues showed that circDDX17 was significantly down-regulated in CRC tissues and associated with unfavorable clinicopathological parameters. In vitro experiments showed that silencing of circDDX17 promoted CRC cell proliferation, migration, invasion, and inhibited apoptosis.
In conclusion, we have identified numerous circRNAs that are dysregulated in CRC tissues compared with adjacent normal mucosa tissues. Bioinformatic analyses suggested that these dysregulated circRNAs might play important functional roles in CRC tumorigenesis. CircDDX17 functions as a tumor suppressor and could serve as a potential biomarker and a therapeutic target for CRC.
How to understand the X(2900)? Wang, Bo; Zhu, Shi-Lin
The European physical journal. C, Particles and fields,
05/2022, Letnik:
82, Številka:
5
Journal Article
Recenzirano
Odprti dostop
In this work, the
S
- and
P
-wave
D
¯
∗
K
∗
interactions are studied in a coupled-channel formalism to understand the recently observed
X
0
(
2900
)
and
X
1
(
2900
)
at LHCb. The experimental event ...distributions can be well described, and two states with
I
(
J
P
)
=
0
(
0
+
)
and
0
(
1
-
)
are yielded in a unified framework. The masses of the
0
+
and
1
-
states are consistent with the experimental data, but the width of the
0
+
state is larger than that of the
1
-
one. The
X
1
(
2900
)
can be interpreted as the
P
-wave excitation of the ground-state
X
0
(
2900
)
in the hadronic molecular picture. The
S
- and
P
-wave multiplets in the
D
¯
∗
K
∗
system have many members, so the present peak in the
D
-
K
+
invariant mass distributions might contain multi substructures.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The design on synthesizing a sturdy, low‐cost, clean, and sustainable electrocatalyst, as well as achieving high performance with low overpotential and good durability toward water splitting, is ...fairly vital in environmental and energy‐related subject. Herein, for the first time the growth of sulfur (S) defect engineered self‐supporting array electrode composed of metallic Re and ReS2 nanosheets on carbon cloth (referred as Re/ReS2/CC) via a facile hydrothermal method and the following thermal treatment with H2/N2 flow is reported. It is expected that, for example, the as‐prepared Re/ReS2‐7H/CC for the electrocatalytic hydrogen evolution reaction (HER) under acidic medium affords a quite low overpotential of 42 mV to achieve a current density of 10 mA cm−2 and a very small Tafel slope of 36 mV decade−1, which are comparable to some of the promising HER catalysts. Furthermore, in the two‐electrode system, a small cell voltage of 1.30 V is recorded under alkaline condition. Characterizations and density functional theory results expound that the introduced S defects in Re/ReS2‐7H/CC can offer abundant active sites to advantageously capture electron, enhance the electron transport capacity, and weaken the adsorption free energy of H* at the active sites, being responsible for its superior electrocatalytic performance.
The S‐defect‐rich ReS2/CC electrocatalyst for highly efficient hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is constructed. The as‐prepared Re/ReS2‐7H/CC affords the overpotentials of 44 and 290 mV at 10 mA cm−2 under alkaline condition for HER and OER, respectively, a small cell voltage of 1.30 V in alkaline medium in the two‐electrode system, which are superior to pristine ReS2/CC.
In this paper, audio and lyrics features of music are fused from the audio and lyrics attributes of modern music tracks to obtain a joint representation of music. The features such as tempo, ...directionality, average value of intensity, beat, and change of rhythm of each musical segment are extracted from the main audio track to form the music feature vector. Subsequently, the music was separated into multiple segments with distinct emotions, and the emotional expression of modern music was evaluated using the Hevner emotion model. Finally, the note extraction performance of this paper’s model is analyzed, and the spectral contrast features of different music pieces and the emotional expression of music pieces under different features are explored. The results show that the pitch patterns of sad emotions are mostly distributed in the range of 0.5-0.55, and the values of the pitch patterns of angry music are basically larger than 0.55. The mean values of the spectral entropy of joy and calmness are mostly distributed in the range of 0.5-0.7, and the sad emotions are mostly in the vicinity of 0.7, while the mean values of the spectral entropy of angry emotions are larger than 0.8.
A generative adversarial network (GAN) usually contains a generative network and a discriminative network in competition with each other. The GAN has shown its capability in a variety of ...applications. In this paper, the usefulness and effectiveness of GAN for classification of hyperspectral images (HSIs) are explored for the first time. In the proposed GAN, a convolutional neural network (CNN) is designed to discriminate the inputs and another CNN is used to generate so-called fake inputs. The aforementioned CNNs are trained together: the generative CNN tries to generate fake inputs that are as real as possible, and the discriminative CNN tries to classify the real and fake inputs. This kind of adversarial training improves the generalization capability of the discriminative CNN, which is really important when the training samples are limited. Specifically, we propose two schemes: 1) a well-designed 1D-GAN as a spectral classifier and 2) a robust 3D-GAN as a spectral-spatial classifier. Furthermore, the generated adversarial samples are used with real training samples to fine-tune the discriminative CNN, which improves the final classification performance. The proposed classifiers are carried out on three widely used hyperspectral data sets: Salinas, Indiana Pines, and Kennedy Space Center. The obtained results reveal that the proposed models provide competitive results compared to the state-of-the-art methods. In addition, the proposed GANs open new opportunities in the remote sensing community for the challenging task of HSI classification and also reveal the huge potential of GAN-based methods for the analysis of such complex and inherently nonlinear data.
Neurocognitive studies of the translation (including interpreting) process have developed quickly for decades. They not only shed new light on the black box of the translating brain but also spark ...discussions in neurolinguistic and neurocognitive issues in the translation process, which are firstly explicated in the paper, underlying a more in-depth explanation of a dynamic view of the neurocognition of translation. This dynamic view is further expounded by a comprehensive analysis of the research findings of ten representative neurocognitive studies in terms of cognitive components and relevant brain areas involved in the translation process. The above analysis reveals the connectivity and complexity of the neural basis of translation and demonstrates the neurocognitive variety of translating under the influence of different factors, such as language proficiency, the translator's age of second language acquisition, translation directionality, and the specific tasks of translation or interpreting, among others. The explication of the dynamic view offers a neurocognitive lens to observe the neural basis of translation psychology more comprehensively on the one hand and raises further problems to explore on the other.
•This paper expounds a dynamic view of neurocognition of translation (and interpreting) through a comprehensive analysis of major neurocognitive studies on bilingual processing, switching, and translation/interpreting.•The explication of the dynamic view offers a neurocognitive lens to observe the neural basis of translation psychology more comprehensively on the one hand and raises further problems to explore on the other.•It demonstrates that translation/interpreting is the most complex bilingual processing which recruits the most extensive brain areas involved in lexico-semantic processing, language control and general cognitive control.•It offers a neurocognitive explanation of simultaneity and expertise in interpreting and demonstrates the embodied nature of translation/interpreting at the neurocognitive level.
Electroreduction of CO2 to acetate provides a promising strategy to reduce CO2 emissions and store renewable energy, but acetate is usually a by‐product. Here, we show a stable and conductive ...two‐dimensional phthalocyanine‐based covalent‐organic framework (COF) as an electrocatalyst for reduction of CO2 to acetate with a single‐product Faradaic efficiency (FE) of 90.3(2)% at −0.8 V (vs. RHE) and a current density of 12.5 mA cm−2 in 0.1 M KHCO3 solution. No obvious degradation was observed over 80 hours of continuous operation. Combined with the comparison of the properties of other catalysts with isolated metal active sites, theoretical calculations and in situ infrared spectroscopy revealed that the isolated copper‐phthalocyanine active site with high electron density is conducive to the key step of C−C coupling of *CH3 with CO2 to produce acetate, and can avoid the coupling of *CO with *CO or *CHO to produce ethylene and ethanol.
Compared to multiple active sites, an isolated active site with high electron density may be more suitable for electroreduction of CO2 towards the C2 product acetate, and can avoid the coupling of *CO with *CO or *CHO to produce ethylene and ethanol.
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