Recently the LHCb collaboration reported a new exotic state
T
cc
+
which possesses
c
c
u
¯
d
¯
flavor structure. Since its mass is very close to the threshold of
D
0
D
∗
+
(or
D
∗
0
D
+
) and its ...width is very narrow, it is inclined to conjecture that
T
cc
+
is a molecular state of
D
0
D
∗
+
(or
D
∗
0
D
+
). In this paper we study the possible molecular structures of
D
(
∗
)
D
(
∗
)
and
B
(
∗
)
B
(
∗
)
within the Bethe–Salpeter (B–S) framework. We employ one boson exchange model to stand the interaction kernels in the B–S equations. With reasonable input parameters we find the isospin eigenstate
1
2
(
D
0
D
∗
+
-
D
∗
0
D
+
)
(
J
P
=
1
+
) constitutes a solution, which supports the ansatz of
T
cc
+
being a molecular state of
D
0
D
∗
+
(or
D
∗
0
D
+
). With the same parameters we also find that the isospin-1 state
1
2
(
D
∗
0
D
∗
+
+
D
∗
0
D
∗
+
)
(
J
P
=
0
+
) can exist. Moreover, we also study the systems of
B
(
∗
)
B
(
∗
)
and their counterparts exist as possible molecular states. Consistency of theoretical computations based on such states with the data of the future experiments may consolidate the molecular structure of the exotic state
T
cc
+
.
We report an enantioselective Michael‐Aldol3+2 annulation between 2‐alkyl‐3‐hydroxynaphthalene‐1,4‐diones and nitroalkenes using a bifunctional thiourea catalyst, and a series of ...nitro‐methanobenzo7annulenes with potential biological activities were synthesized in good yields with excellent enantio‐ and diastereoselectivities. A gram‐scale synthesis and further transformation of the product demonstrated the synthetic value of this reaction.
An enantioselective Michael‐Aldol3+2 annulation via bifunctional thiourea catalysis has been reported, and a series of nitro‐methanobenzo7annulenes with potential biological activities were synthesized in good yields with excellent enantio‐ and diastereoselectivities.
Holey defective g‐C3N4 photocatalysts, which are easily prepared via a novel photoassisted heating process, are reported. The photoassisted treatment not only helps to create abundant holes, endowing ...g‐C3N4 with more exposed catalytic active sites and crossplane diffusion channels to shorten the diffusion distance of both reactants from the surface to bulk and charge carriers from the bulk to surface, but also introduces nitrogen vacancies in the tri‐s‐triazine repeating units of g‐C3N4, inducing the narrowing of intrinsic bandgap and the formation of defect states within bandgap to extend the visible‐light absorption range and suppress the radiative electron–hole recombination. As a result, the holey defective g‐C3N4 photocatalysts show much higher photocatalytic activity for H2O2 production with optimized enhancement up to ten times higher than pristine bulk g‐C3N4. The newly developed synthetic strategy adopted here enables the sufficient utilization of solar energy and shows rather promising for the modification of other materials for efficient energy‐related applications.
A holey defective g‐C3N4 photocatalyst can be prepared through a novel photo‐assisted heating process, and it shows much higher photocatalytic activity for H2O2 production with optimized enhancement up to 10 times higher than pristine bulk g‐C3N4, which is due to the introduction of abundant holes and nitrogen vacancies.
Through a facile and effective strategy by employing lithium molten salts the controlled synthesis of 2H‐ and 1T‐MoS2 monolayers with high‐yield production is achieved. Both phases of MoS2 monolayers ...exhibit high stabilities. When used as a catalyst for hydrogen evolution, these phased MoS2 monolayers deliver respective advantages in the field of electro‐ and photo‐catalytic hydrogen evolution.
We investigate the reaction π−p→π−J/ψp via the open-charm hadron rescattering diagrams. Due to the presence of the triangle singularity (TS) in the rescattering amplitudes, the TS peaks can simulate ...the pentaquark-like resonances arising in the J/ψp invariant mass distributions, which may bring ambiguities on our understanding of the nature of the exotic states. Searching for the heavy pentaquark in different processes may help us to clarify the ambiguities, because of the highly process-dependent characteristic of the TS mechanism.
A simple method is developed to fabricate protonated porous graphitic carbon nitride nanosheets (P‐PCNNS) by protonation–exfoliation of bulk graphitic carbon nitride (BCN) with phosphoric acid ...(H3PO4). The H3PO4 treatment not only helps to exfoliate the BCN into 2D ultrathin nanosheets with abundant micro‐ and mesopores, endowing P‐PCNNS with more exposed active catalytic sites and cross‐plane diffusion channels to facilitate the mass and charge transport, but also induces the protonation of carbon nitride polymer, leading to the moderate removal of the impurities of carbon species in BCN for the optimization of the aromatic π‐conjugated system for better charge separation without changing its chemical structure. As a result, the P‐PCNNS show much higher photocatalytic performance for hydrogen evolution and CO2 conversion than bare BCN and graphitic carbon nitride nanosheets.
A facile approach is developed to fabricate protonated porous g‐C3N4 nanosheets by protonation–exfoliation of bulk g‐C3N4 with phosphoric acid. The prepared protonated porous g‐C3N4 nanosheets exhibit a micro/mesoporous structure and an optimized aromatic π‐conjugated system and show a dramatically improved photocatalytic performance for H2 evolution and CO2 conversion than bulk g‐C3N4 and g‐C3N4 nanosheets.
We investigate the
B
+
→
J
/
ψ
ϕ
K
+
decay via various rescattering diagrams. Without introducing genuine exotic resonances, it is shown that the
Z
cs
(
4000
)
,
Z
cs
(
4220
)
and
X
(4700) reported ...by the LHCb collaboration can be simulated by the
J
/
ψ
K
∗
+
,
ψ
′
K
+
and
ψ
′
ϕ
threshold cusps, respectively. These cusps are enhanced by some nearby triangle singularities. The
X
(4685) with
J
P
=
1
+
cannot be well simulated by the threshold effects in our model, which implies that it may be a genuine resonance.
As the most relevant indicator of global warming, the ocean heat content (OHC) change is tightly linked to the Earth’s energy imbalance. Therefore, it is vital to study the OHC and heat absorption ...and redistribution. Here we analyzed the characteristics of global OHC variations based on a previously reconstructed OHC dataset (named OPEN) with four other gridded OHC datasets from 1993 to 2021. Different from the other four datasets, the OPEN dataset directly obtains OHC through remote sensing, which is reliable and superior in OHC reconstruction, further verified by the Clouds and the Earth’s Radiant Energy System (CERES) radiation flux data. We quantitatively analyzed the changes in the upper 2000 m OHC of the oceans over the past three decades from a multisource and multilayer perspective. Meanwhile, we calculated the global ocean heat uptake to quantify and track the global ocean warming rate and combined it with the Oceanic Niño Index to analyze the global evolution of OHC associated with El Niño–Southern Oscillation variability. The results show that different datasets reveal a continuously increasing and non-decaying global ocean warming from multiple perspectives, with more heat being absorbed by the subsurface and deeper ocean over the past 29 years. The global OHC heating trend from 1993 to 2021 is 7.48 ± 0.17, 7.89 ± 0.1, 10.11 ± 0.16, 7.78 ± 0.17, and 12.8 ± 0.26 × 1022 J/decade according to OPEN, IAP, EN4, Ishii, and ORAS5, respectively, which shows that the trends of the OPEN, IAP, and Ishii datasets are generally consistent, while those of EN4 and ORAS5 datasets are much higher. In addition, the ocean warming characteristics revealed by different datasets are somewhat different. The OPEN OHC dataset from remote sensing reconstruction shows a unique remote sensing mapping advantage, presenting a distinctive warming pattern in the East Indian Ocean. Meanwhile, the OPEN dataset had the largest statistically significant area, with 85.6% of the ocean covered by significant positive trends. The significant and continuous increase in global ocean warming over the past three decades, revealed from remote sensing reconstruction, can provide an important reference for projecting ocean warming in the context of global climate change toward the United Nations Sustainable Development Goals.
SCRaMbLE (Synthetic Chromosome Rearrangement and Modification by LoxP-mediated Evolution) is a genome restructuring technique that can be used in synthetic genomes such as that of Sc2.0, the ...synthetic yeast genome, which contains hundreds to thousands of strategically positioned loxPsym sites. SCRaMbLE has been used to induce rearrangements in yeast strains harboring one or more synthetic chromosomes, as well as plasmid DNA in vitro and in vivo. Here we describe a collection of heterozygous diploid strains produced by mating haploid semisynthetic Sc2.0 strains to haploid native parental strains. We subsequently demonstrate that such heterozygous diploid strains are more robust to the effects of SCRaMbLE than haploid semisynthetic strains, rapidly improve rationally selected phenotypes in SCRaMbLEd heterozygous diploids, and establish that multiple sets of independent genomic rearrangements are able to lead to similar phenotype enhancements. Finally, we show that heterozygous diploid SCRaMbLE can also be carried out in interspecies hybrid strains.
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