In this work, we systematically study the mass spectra and strong decays of 1
P
and 2
S
charmed and charmed-strange baryons in the framework of non-relativistic constituent quark models. With the ...light quark cluster–heavy quark picture, the masses are simply calculated by a potential model. The strong decays are studied by the Eichten–Hill–Quigg decay formula. Masses and decay properties of the well-established 1
S
and 1
P
states can be reproduced by our method.
Σ
c
(
2800
)
0
,
+
,
+
+
can be assigned as a
Σ
c
2
(
3
/
2
-
)
or
Σ
c
2
(
5
/
2
-
)
state. We prefer to interpret the signal
Σ
c
(
2850
)
0
as a
2
S
(
1
/
2
+
)
state although at present we cannot thoroughly exclude the possibility that this is the same state as
Σ
c
(
2800
)
0
.
Λ
c
(
2765
)
+
or
Σ
c
(
2765
)
+
could be explained as the
Λ
c
+
(
2
S
)
state or
Σ
c
1
+
(
1
/
2
-
)
state, respectively. We propose to measure the branching ratio of
B
(
Σ
c
(
2455
)
π
)
/
B
(
Σ
c
(
2520
)
π
)
in the future, which may disentangle the puzzle of this state. Our results support
Ξ
c
(
2980
)
0
,
+
as the first radial excited state of
Ξ
c
(
2470
)
0
,
+
with
J
P
=
1
/
2
+
. The assignment of
Ξ
c
(
2930
)
0
is analogous to
Σ
c
(
2800
)
0
,
+
,
+
+
, i.e., a
Ξ
c
2
′
(
3
/
2
-
)
or
Ξ
c
2
′
(
5
/
2
-
)
state. In addition, we predict some typical ratios among partial decay widths, which are valuable for experimental search for these missing charmed and charmed-strange baryons.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We apply a new mass formula which is derived analytically in the relativistic flux tube model to the mass spectra of
Λ
Q
and
Ξ
Q
(
Q
=
c
or
b
quark) baryons. To this end, the heavy quark-light ...diquark picture is employed. We find that all masses of the available
Λ
Q
and
Ξ
Q
states can be understood well. The assignments to these states do not appear to contradict the strong decay properties.
Λ
c
(2760)
+
and
Ξ
c
(2980) are assigned to the first radial excitations with
J
P
= 1/2
+
.
Λ
c
(2940)
+
and
Ξ
c
(3123) might be the 2
P
states. The
Λ
c
(2880)
+
and
Ξ
c
(3080) are the good 1
D
candidates with
J
P
= 5/2
+
.
Λ
c
(3055) is likely to be a 1
D
state with
J
P
=3/2
+
.
Λ
b
(5912)
0
and
Λ
b
(5920)
0
favor the 1
P
assignments with
J
P
= 1/2
−
and 3/2
−
, respectively. We propose a search for the
state which can help to distinguish the diquark and three-body schemes.
Selecting the newly observed Ξb(6227)− by LHCb as a study example, we decode its inner structure by giving the mass spectrum analysis and the investigation of its two-body strong decay behaviors. Our ...result indicates that the Ξb(6227)− is a good candidate of the P-wave Ξb′ state with JP=3/2− or 5/2−. In addition, we further provide the information of the properties of the partners of the Ξb(6227)−. These predicted states include three 2S states and the remaining 1P states in the bottom-strange baryon family. The calculated sizable Okubo-Zweig-Iizuka–allowed decay widths of these partners show that the experimental search for them becomes possible via LHCb. We have a reason to believe that the present study can be treated as a start point for constructing the highly excited bottom baryon spectroscopy.
A new strategy for enantioselective synthesis of axially chiral naphthyl‐indoles has been established through catalytic asymmetric addition reactions of racemic naphthyl‐indoles with bulky ...electrophiles. Under chiral phosphoric acid catalysis, azodicarboxylates and o‐hydroxybenzyl alcohols served as bulky but reactive electrophiles that were attacked by C2‐unsubstituted naphthyl‐indoles, which underwent a dynamic kinetic resolution to afford two series of axially chiral naphthyl‐indoles in good yields (up to 98 %) and high enantioselectivities (up to 98:2 er).
A new strategy for enantioselective synthesis of axially chiral naphthyl‐indoles was established by catalytic asymmetric addition reactions of racemic naphthyl‐indoles with bulky electrophiles. Under chiral Brønsted acid (B*−H) catalysis, azodicarboxylates and o‐hydroxybenzyl alcohols served as bulky but reactive electrophiles that were attacked by C2‐unsubstituted naphthyl‐indoles, affording axially chiral naphthyl‐indoles in good yields and enantioselectivities.
The first highly atroposelective construction of N−N axially chiral indole scaffolds was established via a new strategy of de novo ring formation. This strategy makes use of the organocatalytic ...asymmetric Paal–Knorr reaction of well‐designed N‐aminoindoles with 1,4‐diketones, thus affording N‐pyrrolylindoles in high yields and with excellent atroposelectivities (up to 98 % yield, 96 % ee). In addition, this strategy is applicable for the atroposelective synthesis of N−N axially chiral bispyrroles (up to 98 % yield, 97 % ee). More importantly, such N−N axially chiral heterocycles can be converted into chiral organocatalysts with applications in asymmetric catalysis, and some molecules display potent anticancer activity. This work not only provides a new strategy for the atroposelective synthesis of N−N axially chiral molecules but also offers new members of the N−N atropisomer family with promising applications in synthetic and medicinal chemistry.
The first highly atroposelective construction of N−N axially chiral indole scaffolds was established via a new strategy of de novo ring formation, which is also applicable for the synthesis of N−N axially chiral bispyrroles. Such N−N axially chiral heterocycles can be converted into chiral organocatalysts. They may also display potent anticancer activity, thus offering new members of the N−N atropisomer family with promising applications in synthetic and medicinal chemistry.
Mortality from hepatitis B virus (HBV)–related acute‐on‐chronic liver failure (ACLF) is high due to limited treatment options. Preclinical and clinical investigations have proved that treatment with ...mesenchymal stromal cells (MSCs) is beneficial for recovery from liver injury. We hypothesized that the outcome of HBV‐related ACLF would be improved by MSC treatment. From 2010 to 2013, 110 patients with HBV‐related ACLF were enrolled in this open‐label, nonblinded randomized controlled study. The control group (n = 54) was treated with standard medical therapy (SMT) only. The experimental group (n = 56) was infused weekly for 4 weeks with 1.0 to 10 × 105 cells/kg allogeneic bone marrow–derived MSCs and then followed for 24 weeks. The cumulated survival rate of the MSC group was 73.2% (95% confidence interval 61.6%‐84.8%) versus 55.6% (95% confidence interval 42.3%‐68.9%) for the SMT group (P = 0.03). There were no infusion‐related side effects, but fever was more frequent in MSC compared to SMT patients during weeks 5‐24 of follow‐up. No carcinoma occurred in any trial patient in either group. Compared with the control group, allogeneic bone marrow–derived MSC treatment markedly improved clinical laboratory measurements, including serum total bilirubin and Model for End‐Stage Liver Disease scores. The incidence of severe infection in the MSC group was much lower than that in the SMT group (16.1% versus 33.3%, P = 0.04). Mortality from multiple organ failure and severe infection was higher in the SMT group than in the MSC group (37.0% versus 17.9%, P = 0.02). Conclusion: Peripheral infusion of allogeneic bone marrow–derived MSCs is safe and convenient for patients with HBV‐related ACLF and significantly increases the 24‐week survival rate by improving liver function and decreasing the incidence of severe infections. (Hepatology 2017;66:209–219).
Recently LHCb declared a new structure
X
(6900) in the final state di-
J
/
ψ
which is popularly regarded as a
cc
-
c
¯
c
¯
tetraquark state. Within the Bethe–Salpeter (B–S) framework we study the ...possible
cc
-
c
¯
c
¯
bound states and the interaction between diquark (
cc
) and antidiquark (
c
¯
c
¯
). In this work
cc
(
c
¯
c
¯
) is treated as a color anti-triplet (triplet) axial-vector so the quantum numbers of
cc
-
c
¯
c
¯
bound state are
0
+
,
1
+
and
2
+
. Learning from the interaction in meson case and using the effective coupling we suggest the interaction kernel for the diquark and antidiquark system. Then we deduce the B–S equations for different quantum numbers. Solving these equations numerically we find the spectra of some excited states can be close to the mass of
X
(6900) when we assign appropriate values for parameter
κ
introduced in the interaction (kernel). We also briefly calculate the spectra of
bb
-
b
¯
b
¯
bound states. Future measurement of
bb
-
b
¯
b
¯
state will help us to determine the exact form of effective interaction.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A copper‐catalyzed cyclization reaction of 2‐(3‐arylpropioloyl)benzaldehydes was developed, leading to benzylated 1,4‐naphthoquinones via radical‐triggered cascade cyclization. This example of an ...acylbenzylation involving internal alkynes could be carried out with a broad substrate scope and wide functional group tolerance.
Recently, some singly bottom baryons have been established experimentally, but none of the doubly or triply bottom baryons have been observed. Under the Regge phenomenology, the mass of an unobserved ...ground-state doubly or triply bottom baryon is expressed as a function of masses of the well-established light baryons and singly bottom baryons. Then, the values of Regge slopes and Regge intercepts for baryons containing one, two, or three bottom quarks are calculated. After that, the masses of the orbitally excited singly, doubly, and triply bottom baryons are estimated. Our predictions may be useful for the discovery of these baryons and their JP assignments.
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