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Stimulated by the exciting progress in the observation of new bottomonium states, we study the bottomonium spectrum. To calculate the mass spectrum, we adopt a nonrelativistic screened potential model. The radial Schr\"{o}dinger equation is solved with the three-point difference central method, where the spin-dependent potentials are dealt with non-perturbatively. With this treatment, the corrections of the spin-dependent potentials to the wave functions can be included successfully. Furthermore, we calculate the electromagnetic transitions of the $nS$ ($n\leq 4$), $nP$ ($n\leq 3$), and $nD$ ($n\leq 2$) bottomonium states with a nonrelativistic electromagnetic transition operator widely applied to meson photoproduction reactions. Our predicted masses, hyperfine and fine splittings, electromagnetic transition widths and branching ratios of the bottomonium states are in good agreement with the available experimental data. Especially, the EM transitions of $\Upsilon(3S)\to \chi_{b1,2}(1P)\gamma$, which were not well understood in previous studies, can be reasonably explained by considering the corrections of the spin-dependent interactions to the wave functions. We also discuss the observations of the missing bottomonium states by using radiative transitions. Some important radiative decay chains involving the missing bottomonium states are suggested to be observed. We hope our study can provide some useful references to observe and measure the properties of bottomonium mesons in forthcoming experiments.Comment: 14 pages, 1 figure, revised version. To appear in PR

The charmonium spectrum is calculated with two nonrelativistic quark models, the linear potential model and the screened potential model. Using the obtained wavefunctions, we evaluate the electromagnetic transitions of charmonium states up to 4S multiplet. The higher multipole contributions are included by a multipole expansion of the electromagnetic interactions. Our results are in reasonable agreement with the measurements. As conventional charmonium states, the radiative decay properties of the newly observed charmonium-like states, such as X(3823), X(3872), X(4140/4274), are discussed. The X(3823) as ψ 2 (1D), its radiative decay properties well agree with the observations. From the radiative decay properties of X(3872), one can not exclude it as a χ c1 (2P) dominant state. We also give discussions of possibly observing the missing charmonium states in radiative transitions, which might provide some useful references to look for them in forthcoming experiments. The higher multipole contributions to the electromagnetic transitions are analyzed as well. It is found that the higher contribution from the magnetic part could give notable corrections to some E1 dominant processes by interfering with the E1 amplitudes. Our predictions for the normalized magnetic quadrupole amplitudes M 2 of the χ c1,2 (1P) → J/ψγ processes are in good agreement with the recent CLEO measurements.

Objectives To assess the prevalence of complicated appendicitis (including gangrene, abscess and perforation) after the outbreak of the 2019-nCoV epidemic and to identify the risk factors associated with complicated appendicitis. Methods Two groups were established in the study consisting of: one group for cases of acute appendicitis before the 2019-nCoV epidemic (before January 1, 2020; pre-epidemic group) and another group for those after the epidemic outbreak (after January 1, 2020; epidemic group). These two groups were compared in terms of demographic and clinical characteristics, prevalence of complicated appendicitis, and treatment intention. A multivariate analysis model using binary logistic regression was constructed. Results A total of 163 patients were included in this study, with 105 in the pre-epidemic group and 58 in the epidemic group. In the epidemic group, the interval from the onset of symptoms to admission was 65.0 h, which is significantly longer than the 17.3 h interval noted in the pre-epidemic group ( P < 0.001). The prevalence of complicated appendicitis after the epidemic outbreak was significantly higher than before the outbreak (51.7% vs. 12.4%, P < 0.001). In addition, the epidemic group had a lower score of patient’s intention to seek treatment than the pre-epidemic group (9.5 ± 2.7 vs. 3.4 ± 2.6, P < 0.001). Based on the multivariate analysis, the risk factors for complicated appendicitis included the time from symptoms onset to admission (OR = 1.075) and the patients’ intention to receive treatment (OR = 0.541). Conclusion Complicated appendicitis was more common in patients with acute appendicitis after the outbreak of the 2019-nCoV epidemic.

The preparation methods and applications of flavor and fragrance capsules based on polymeric, inorganic and polymeric–inorganic wall materials are summarized.