[en] Objective: By analysing the relation between the proportion of NBCA and the arteriovenous circulation time to give the optimal proportion of NBCA for embolizing cerebral AVM with microcatheter clinically. Methods: (1) The fresh arterial blood fractions from intracranial hemorrhage in vitro of 16 cases were mixed with the 20%, 33%, 50%, 70% and 80% NBCA respectively and evaluated the coagulation times with the different densities of NBCA in the fresh arterial blood in vitro; (2) two cases were performed with superselective embolotherapy to five feeding artery. Results: (1) the correlation index between different densities of NBCA and the fresh arterial blood in vitro, T_(c)=e^{1.9994-1.487D}, (2) about 90% nidus of AVM were occluded after embolization, and the fistulas of AVF were basically closed after embolization. Conclusions: There is a mathematical model between the arteriovenous circulation time and the proportion of NBCA, thus providing the theoretical clinical application of the embolotherapy of CAVM with microcatheter

[en] Objective: To evaluate the effect of bronchial artery embolization for treatment of massive hemoptysis. Methods: Between 2003 and 2009, 136 patients (87 men and 49 women, mean 49.6 years) who presented with massive hemoptysis of 500 to 1000 mL in 24 hours underwent bronchial artery or intercostal artery embolization. The main causes of hemoptysis were tuberculosis (28), bronchiectasis (102), and lung cancer (6). Embolization was performed with particles of gelfoam, PVA and /or coil. Results: Of 136 patients, hemoptysis was controlled in 129 patients after one treatment. Seven patients required repeat embolization. The effective rate was 100% with no serious complication. Conclusion: Bronchial or intercostal artery embolization is an effective and safe treatment for massive hemoptysis. (authors)

[en] The engines that produce extragalactic fast radio bursts (FRBs), and the mechanism by which the emission is generated, remain unknown. Many FRB models predict prompt multiwavelength counterparts, which can be used to refine our knowledge of these fundamentals of the FRB phenomenon. However, several previous targeted searches for prompt FRB counterparts have yielded no detections and have additionally not reached sufficient sensitivity with respect to the predictions. In this work, we demonstrate a technique to estimate the ratio, η, between the energy outputs of FRB counterparts at various wavelengths and the radio-wavelength emission. Our technique combines the fluence distribution of the FRB population with results from several wide-field blind surveys for fast transients from the optical to the TeV bands. We present constraints on η that improve upon previous observations even in the case where all unclassified transient events in existing surveys are FRB counterparts. In some scenarios for the FRB engine and emission mechanism, we find that FRB counterparts should have already been detected, thus demonstrating that our technique can successfully test predictions for η. However, it is possible that FRB counterparts are lurking among catalogs of unclassified transient events. Although our technique is robust to the present uncertainty in the FRB fluence distribution, its ultimate application to accurately estimate or bound η will require the careful analysis of all candidate fast transient events in multiwavelength survey data sets.

[en] Objective: To observe the relation between pathologic tumor response to concurrent chemo-radiotherapy and the serum VEGF level, and to explore its corresponding influence on the efficacy and prognosis in patients with esophageal carcinoma. Methods: Totally 46 cases of patients with esophageal cancer who received concurrent chemo-radiotherapy were enrolled. The gastroscopy and pathologic examination were conducted before and 4 weeks afterwards. Meanwhile, the serum VEGF level and X-ray barium of esophageal image were measured before, 4 weeks later and after the radiotherapy. The relation between the tumor pathologic response and the changes of the serum VEGF level and its influence on the efficacy and prognosis were analyzed. Results: There were 18 cases (85.7%), 7 cases (53.8%) and 6 cases (50.0%) whose serum VEGF level dropped in the severe, moderate and mild group, respectively, and significant differences among these groups(χ² = 6.072, P < 0.05). There were 19 cases (90.5%), 5 cases (38.5%) and 4 cases (33.3%) whose response measured as effective in the severe, moderate and mild group, respectively, and significant differences among these groups(χ² = 14.289, P < 0.05)). The 2-year survival rates of the severe, there was no statistically difference between the severe and mild group on OS. There were 22 cases (71.0%), 6 cases(40.0%) and 4 cases (33.3%) whose response measured as effective in the serum VEGF level drop and increase group, respectively, and significant differences between these groups(χ² = 14.289, P < 0.05)). Conclusions: The tumor pathologic response during chemo-radiotherapy and the changes of the serum VEGF lever may predict the curative effect of chemo-radiotherapy in the patients with esophageal cancer. To monitor the tumor pathologic response and the changes of the serum VEGF levels may be valuable for individualized treatment for esophageal cancer patients. (authors)

[en] At present, most of the diesel generating units in domestic nuclear power plants have adopted the PA machine as the original motive. This model has the characteristics of reliable operation and convenient maintenance. However, in recent years, the failure of the unit has been frequent. During the field delivery test of a domestic nuclear power plant and a diesel generator set, serious accidents such as starting air pipeline burning and opening of crankcase explosion proof doors have occurred. After site exploration, and through the fault tree, all factors that caused the accident were investigated, and the root causes and solutions of the accident were finally determined, which played a guiding role in the late manufacture and on-site commissioning of the crew. (authors)

[en] Given the possible repetitive nature of fast radio bursts (FRBs), their cosmological origin, and their high occurrence, detection of strongly lensed sources due to intervening galaxy lenses is possible with forthcoming radio surveys. We show that if multiple images of a repeating source are resolved with VLBI, using a method independent of lens modeling, accurate timing could reveal non-uniform motion, either physical or apparent, of the emission spot. This can probe the physical nature of FRBs and their surrounding environments, constraining scenarios including orbital motion around a stellar companion if FRBs require a compact star in a special system, and jet-medium interactions for which the location of the emission spot may randomly vary. The high timing precision possible for FRBs (∼ms) compared with the typical time delays between images in galaxy lensing (≳10 days) enables the measurement of tiny fractional changes in the delays ($\sim <!--\; ???\; -->{10}^{-<!--\; ???\; -->9}$) and hence the detection of time-delay variations induced by relative motions between the source, the lens, and the Earth. We show that uniform cosmic peculiar velocities only cause the delay time to drift linearly, and that the effect from the Earth’s orbital motion can be accurately subtracted, thus enabling a search for non-trivial source motion. For a timing accuracy of ∼1 ms and a repetition rate (of detected bursts) of ∼0.05 per day of a single FRB source, non-uniform displacement ≳0.1–1 au of the emission spot perpendicular to the line of sight is detectable if repetitions are seen over a period of hundreds of days.

[en] We consider the situation where the luminosity from a transient event is reprocessed by an optically thick wind. Potential applications are the tidal disruption of stars by black holes (BHs), engine-powered supernovae, and unique fast transients found by current and future wide-field surveys. We derive relations between the injected and observed luminosity for steady and time-dependent winds, and discuss how the temperature is set for scattering-dominated radiative transport. We apply this framework to specific examples of tidal disruption events and the formation of a BH by a massive star, as well as discuss other applications such as deriving observables from detailed hydrodynamic simulations. We conclude by exploring what is inferred about the mass-loss rate and underlying engine powering AT 2018cow if it is explained as a wind-reprocessed transient, demonstrating that its optical emission is consistent with reprocessing of the observed soft X-rays.

[en] Observational evidence suggests that the majority of stars may have been born in stellar clusters or associations. Within these dense environments, dynamical interactions lead to high rates of close stellar encounters. A variety of recent observational and theoretical indications suggest stellar-mass black holes may be present and play an active dynamical role in stellar clusters of all masses. In this study, we explore the tidal disruption of main-sequence stars by stellar-mass black holes in young star clusters. We compute a suite of over 3000 independent N-body simulations that cover a range of cluster mass, metallicity, and half-mass radii. We find stellar-mass black hole tidal disruption events (TDEs) occur at an overall rate of up to roughly 200 Gpc⁻³ yr⁻¹ in young stellar clusters in the local universe. These TDEs are expected to have several characteristic features, namely, fast rise times of order a day, peak X-ray luminosities of at least 10⁴⁴ erg s⁻¹, and bright optical luminosities (roughly 10⁴¹–10⁴⁴ erg s⁻¹) associated with reprocessing by a disk wind. In particular, we show these events share many features in common with the emerging class of Fast Blue Optical Transients.

[en] The discovery rate of fast radio bursts (FRBs) is increasing dramatically thanks to new radio facilities. Meanwhile, wide-field instruments such as the 47 deg² Zwicky Transient Facility (ZTF) survey the optical sky to study transient and variable sources. We present serendipitous ZTF observations of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) repeating source FRB 180916.J0158+65 that was localized to a spiral galaxy 149 Mpc away and is the first FRB suggesting periodic modulation in its activity. While 147 ZTF exposures corresponded to expected high-activity periods of this FRB, no single ZTF exposure was at the same time as a CHIME detection. No >3σ optical source was found at the FRB location in 683 ZTF exposures, totaling 5.69 hr of integration time. We combined ZTF upper limits and expected repetitions from FRB 180916.J0158+65 in a statistical framework using a Weibull distribution, agnostic of periodic modulation priors. The analysis yielded a constraint on the ratio between the optical and radio fluences of η ≲ 200, corresponding to an optical energy E _opt ≲ 3 × 10⁴⁶ erg for a fiducial 10 Jy ms FRB (90% confidence). A deeper (but less statistically robust) constraint of η ≲ 3 can be placed assuming a rate of $r(><!--\; >\; -->5\mathrm{J}\mathrm{y}\mathrm{m}\mathrm{s})=1{\mathrm{h}\mathrm{r}}^{-<!--\; ???\; -->1}$ and 1.2 ± 1.1 FRB occurring during exposures taken in high-activity windows. The constraint can be improved with shorter per-image exposures and longer integration time, or observing FRBs at higher Galactic latitudes. This work demonstrated how current surveys can statistically constrain multiwavelength counterparts to FRBs even without deliberately scheduled simultaneous radio observation.