The
D
(
∗
)
Ξ
cc
(
∗
)
system and
Ξ
¯
cc
(
∗
)
Ξ
cc
(
∗
)
system can be related to the
D
(
∗
)
D
¯
(
∗
)
system via heavy anti-quark di-quark symmetry (HADS). In this work, we employ a contact-range ...effective field theory to systematically investigate the likely existence of molecules in these systems in terms of the hypothesis that X(3872) is a
1
+
+
D
D
¯
∗
bound state in the isospin symmetry limit, with some of the unknown low energy constants estimated using the light-meson saturation approximation. In the meson–meson system, a
J
PC
=
2
+
+
D
¯
∗
D
∗
molecule commonly referred to as
X
(4013) is reproduced, which is the heavy quark spin partner of
X
(3872). In the meson-baryon system, we predict two triply charmed pentaquark molecules,
J
P
=
1
/
2
-
D
∗
Ξ
cc
and
J
P
=
5
/
2
-
D
∗
Ξ
cc
∗
. In the baryon-baryon system, there exist seven di-baryon molecules,
J
PC
=
0
-
+
Ξ
¯
cc
Ξ
cc
,
J
PC
=
1
-
-
Ξ
¯
cc
Ξ
cc
,
J
PC
=
1
-
+
Ξ
¯
cc
Ξ
cc
∗
,
J
PC
=
1
-
-
Ξ
¯
cc
Ξ
cc
∗
,
J
PC
=
2
-
+
Ξ
¯
cc
Ξ
cc
∗
,
J
PC
=
2
-
+
Ξ
¯
cc
∗
Ξ
cc
∗
, and
J
PC
=
3
-
-
Ξ
¯
cc
∗
Ξ
cc
∗
. Among them, the
J
PC
=
0
-
+
Ξ
¯
cc
Ξ
cc
molecule may contribute to the
X
(7200) state recently observed by the LHCb Collaboration, which implies that
X
(7200) can be related to
X
(3872) via HADS. As a byproduct, with the heavy quark flavor symmetry we also study likely existence of molecular states in the
B
(
∗
)
B
¯
(
∗
)
,
B
¯
(
∗
)
Ξ
bb
(
∗
)
, and
Ξ
¯
bb
(
∗
)
Ξ
bb
(
∗
)
systems.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cyclization of propargylamines with CO2 to obtain 2‐oxazolidone heterocyclic compounds is an essential reaction in industry but it is usually catalyzed by noble‐metal catalysts with organic bases as ...co‐catalysts under harsh conditions. We have synthesized a unique CuI/CuII mixed valence copper‐based framework {(CuI6I5)Cu3IIL6(DMA)3(NO3)⋅9DMA}n (1) with good solvent and thermal stability, as well as a high density of uncoordinated amino groups evenly distributed in the large nanoscopic channels. Catalytic experiments show that 1 can effectively catalyze the reaction of propargylamines with CO2, and the yield can reach 99 %. The turnover frequency (TOF) reaches a record value of 230 h−1, which is much higher than that of reported noble‐metal catalysts. Importantly, this is the first report of heterogeneously catalyzed green conversion of propargylamines with CO2 without solvents and co‐catalysts under low temperature and atmospheric pressure. A mechanistic study reveals that a triply synergistic catalytic effect between CuI/CuII and uncoordinated amino groups promotes highly efficient and green conversion of CO2. Furthermore, 1 directly catalyzes this reaction with high efficiency when using simulated flue gas as a CO2 source.
A mixed valence copper‐based cationic framework {(CuI6I5)Cu3IIL6(DMA)3(NO3)⋅9DMA}n was synthesized. The material realized the efficient and green conversion of propargylamine with CO2 in flue gas under solvent‐free and co‐catalyst free conditions.
A recent analysis by the LHCb Collaboration suggests the existence of three narrow pentaquarklike states-the P_{c}(4312), P_{c}(4440), and P_{c}(4457)-instead of just one in the previous analysis the ...P_{c}(4450). The closeness of the P_{c}(4312) to the Dover ¯Σ_{c} threshold and the P_{c}(4440) and P_{c}(4457) to the Dover ¯^{*}Σ_{c} threshold suggests a molecular interpretation of these resonances. We show that these three pentaquarklike resonances can be naturally accommodated in a contact-range effective field theory description that incorporates heavy-quark spin symmetry. This description leads to the prediction of all the seven possible S-wave heavy antimeson-baryon molecules that is, there should be four additional molecular pentaquarks in addition to the P_{c}(4312), P_{c}(4440), and P_{c}(4457), providing the first example of a heavy-quark spin symmetry molecular multiplet that is complete. If this is confirmed, it will not only give us an impressive example of the application of heavy-quark symmetries and effective field theories in hadron physics, it will also uncover a clear and powerful ordering principle for the molecular spectrum, reminiscent of the SU(3)-flavor multiplets to which the light hadron spectrum conforms.
Inspired by the recent discovery of a doubly charmed tetraquark state Tcc+ by the LHCb Collaboration, we employ the effective Lagrangian approach to investigate the decay width of Tcc+→D+D0π0/D0D0π+ ...and Tcc+→D0D+γ with the assumption that Tcc+ is an isoscalar DD⁎ molecule. We show that both the Tcc→DDπ and Tcc→DDγ modes contribute to the decay width of Tcc, with the former being dominant. The resulting total decay width of about Γ=63 keV is smaller than the experimental decay width obtained from the Breit-Wigner fit of the LHCb data, Γ=410±165±43−38+18 keV, while close to the number obtained from the alternative unitary analysis, Γ=48±2−14+0 keV, which supports the molecular nature of Tcc.
Lately, the LHCb Collaboration reported the discovery of two new states in the
B
+
→
D
+
D
-
K
+
decay, i.e.,
X
0
(
2866
)
and
X
1
(
2904
)
. In the present work, we study whether these states can be ...understood as
D
¯
∗
K
∗
molecules from the perspective of their two-body strong decays into
D
-
K
+
via triangle diagrams and three-body decays into
D
¯
∗
K
π
. The coupling of the two states to
D
¯
∗
K
∗
are determined from the Weinberg compositeness condition, while the other relevant couplings are well known. The obtained strong decay width for the
X
0
(
2866
)
state, in marginal agreement with the experimental value within the uncertainty of the model, hints at a large
D
¯
∗
K
∗
component in its wave function. On the other hand, the strong decay width for the
X
1
(
2904
)
state, much smaller than its experimental counterpart, effectively rules out its assignment as a
D
¯
∗
K
∗
molecule.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Self‐assembly is important for creating photonic structures and structural color is typically tunable by varying the size of building blocks, which are themselves obtained after time‐consuming ...chemical syntheses. The molecular conformation of bottlebrush block copolymers (BBCPs) in solution can be manipulated to create libraries of photonic structures. Amphiphilic BBCPs bearing oxidation‐responsive ferrocene groups on the hydrophilic block are used to fabricate porous particles via evaporation‐induced self‐assembly of water‐in‐oil‐in‐water (W/O/W) double emulsions stabilized by the BBCP surfactant. In situ oxidation of the ferrocene groups by hydrogen peroxide at the W/O interface leads to enhanced hydrophilicity, more hydration, and chain extension of the hydrophilic block. Consequently, larger internal water droplets are spontaneously formed, yielding larger pores within the microparticles. The pore diameter is readily tunable from 144 to 301 nm with a single BBCP, thereby generating full‐spectrum structural colors. This work provides a straightforward method for fabrication of libraries of photonic pigments in an easy and scalable manner.
Molecular conformation of amphiphilic bottlebrush block copolymers (PS‐b‐PEOFeCp) is successfully manipulated to create libraries of inverse photonic structures that exhibit full‐spectrum structural colors. In situ oxidation of ferrocene groups grafted on the poly(ethylene oxide) (PEO) block leads to polymer chain elongation in water‐in‐oil‐in‐water double emulsions, resulting in larger internal droplets and thus larger porous structures.
In the present work, we assign the newly observed Pc(4312) as a I(JP) = 1/2(1/2)− molecular state composed of ΣcD¯, while Pc(4440) and Pc(4457) as ΣcD¯* molecular states with I(JP) = 1/2(1/2)− and ...1/2(3/2)−, respectively. In this molecular scenario, we investigate the Pc → J/ψp process of these three states and further predict the ratios of the B(Pc → J/ψp) and those of B(Λb → PcK) between these three states, which could serve as a crucial test of the present molecular scenario.
The pentaquark states Pc(4312), Pc(4440), and Pc(4457) could be nicely arranged into a multiplet of seven molecules of ¯D(*)Σ(*)c dictated by heavy quark spin symmetry. However, the spins of Pc(4440) ...and Pc(4457) are not yet fully determined. We employ the contact-range effective field theory to investigate the SU(3)-flavor counterparts of ¯D(*)Σ(*)c and study the possibility of whether their discovery could help determine the spins of Pc(4457) and Pc(4440). We find the existence of a complete hidden charm strange multiplet of ¯D(*)Ξ(')*c molecules, irrespective of the spins of Pc(4440) and Pc(4457). On the other hand, we find that although molecules of ¯D(*)Ξc are also likely, depending on the realization of the underlying dynamics, their discovery could be more useful for determining the spins of Pc(4440) and Pc(4457) and for telling us how heavy quark and light quark interactions depend on the spin of the light quark pair.
Lung cancer is the leading cause of cancer-related mortality for males and females. Radiation therapy (RT) is one of the primary treatment modalities for lung cancer. While delivering the prescribed ...dose to tumor targets, it is essential to spare the tissues near the targets-the so-called organs-at-risk (OARs). An optimal RT planning benefits from the accurate segmentation of the gross tumor volume and surrounding OARs. Manual segmentation is a time-consuming and tedious task for radiation oncologists. Therefore, it is crucial to develop automatic image segmentation to relieve radiation oncologists of the tedious contouring work. Currently, the atlas-based automatic segmentation technique is commonly used in clinical routines. However, this technique depends heavily on the similarity between the atlas and the image segmented. With significant advances made in computer vision, deep learning as a part of artificial intelligence attracts increasing attention in medical image automatic segmentation. In this article, we reviewed deep learning based automatic segmentation techniques related to lung cancer and compared them with the atlas-based automatic segmentation technique. At present, the auto-segmentation of OARs with relatively large volume such as lung and heart etc. outperforms the organs with small volume such as esophagus. The average Dice similarity coefficient (DSC) of lung, heart and liver are over 0.9, and the best DSC of spinal cord reaches 0.9. However, the DSC of esophagus ranges between 0.71 and 0.87 with a ragged performance. In terms of the gross tumor volume, the average DSC is below 0.8. Although deep learning based automatic segmentation techniques indicate significant superiority in many aspects compared to manual segmentation, various issues still need to be solved. We discussed the potential issues in deep learning based automatic segmentation including low contrast, dataset size, consensus guidelines, and network design. Clinical limitations and future research directions of deep learning based automatic segmentation were discussed as well.
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