We present a microscopic calculation of α-cluster formation in heavy nuclei 104 Te (α+ 100 Sn), 212 Po (α+ 208 Pb) and their neighbors 102 Sn, 102 Te, 210 Pb and 210 Po by using the quartetting wave function approach. Improving the local density approximation, the shell structure of the core nucleus is considered, and the center-of-mass (c.o.m.) effective potential for the quartet is obtained self-consistently from the shell model wavefunctions. The α-cluster formation and decay probabilities are obtained by solving the bound-state of the c.o.m. motion of the quartet and the scattering state of the formed α-cluster in the Gurvitz approach. Striking shell effects on the α-cluster formation probabilities are analyzed for magic numbers 50, 82 and 126. The computed α-decay half-lives of these special nuclei are compared with the newest experimental data.
Well-designed second near-infrared (NIR-II) fluorophores are promising in optical diagnosis and therapy of tumors. In this work, we synthesized a donor−acceptor−donor (D−A−D) NIR-II fluorophore named BBTD-BET with dithienylethene as an electron donor and benzobisthiadiazole as an electron acceptor. To the best of our knowledge, this is the first report of using dithienylethene, a typical photochromic molecule, as a building block for NIR-II fluorophores. We studied the geometrical configuration, electronic state, and optical properties of BBTD-BET by both theoretical and experimental means. BBTD-BET had absorption and emission in the NIR-I and NIR-II spectral ranges, respectively. Using PEGylated BBTD-BET as a theranostic agent, we achieved NIR-II fluorescence/photoacoustic (PA) dual-modal imaging and attained high imaging resolution, desired signal-to-noise ratio, and excellent photothermal therapy (PTT) efficacy. After one PTT treatment, the tumors established in mice were eradicated. This work provides a novel organic conjugated molecule integrating NIR-II/PA dual-modal imaging and PTT functionalities that is very promising in the theranostic of tumors.
LHCb collaboration has recently announced a measurement of the difference of time-integrated CP asymmetries between D → K + K − and D → π + π − . This result provides the evidence of large direct CP violation in D meson and reveals some important implications on underlying new physics. It is shown that the direct CP violation in D meson can be enhanced by R-parity violating supersymmetry, while CP violations in K and B mesons are suppressed by this new physics, which is in consistence with previous experiments. Constraints on the model parameters and some consequences are also discussed.
Transition-metal-catalyzed enantioselective addition of aryl organometallic reagents to imines has emerged as one of the most powerful tools for the formation of optically active diarylmethylamines. Here, we report the first asymmetric reductive (hetero)arylations of imines using aryl and heteroaryl halides enabled by a chiral cobalt-bisphosphine catalyst. This approach shows good functional group compatibility and complements the reported strategy without use of organometallic reagents. Mechanistic investigations supported that aryl-cobalt, instead of an arylzinc reagent, was formed in situ in this reductive aryladdition event.
Semiconductor
polymers have several featured advantages, such as
easily tunable optical properties, high light harvesting, good photostability,
etc. However, semiconductor polymers with desirable NIR-II absorbance
for the applications of both NIR-II photoacoustic (PA) imaging and
photothermal therapy (PTT) are still lacking. Herein, we synthesized
a donor–acceptor (D–A) type semiconductor polymer PTPTQ
with thiophene (TP) as the electron donor and thiadiazoloquinoxaline
(TQ) as the acceptor. PTPTQ had a brushlike topological structure
with two poly(ethylene glycol) (PEG) chains (2000 Da) in each repeating
unit. Such an intriguing structure endowed it with high hydrophilicity,
good biocompatibility, and prominent passive tumor targeting ability.
PTPTQ exhibited strong absorption in 600–1800 nm and good photostability.
Its photothermal conversion efficiency was determined to be about
41.36%, which rendered it excellent properties in NIR-II PA imaging
and PTT. By using PTPTQ as a PTT agent, the mouse tumor models can
be eradicated. Taken together, the overall properties of PTPTQ make
it promising as a tumor theranostic agent.
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