Search

The Litang fault (LTF), located in the southeast of the Qinghai-Tibetan Plateau, is known for its high level of present-day seismicity, whereas its Pleistocene activity has been scarcely documented. This study focused on a tract of banded travertine deposits precipitated from thermal waters along the NW–SE-trending LTF trace. The role of travertine deposits in recording neotectonic activity has been studied by identifying their internal structure. Typical soft-sediment deformation structures observed within the banded travertines include micro folds, liquefied breccia, and liquefied diapirs. These deformed structures, which are restricted to a single unit separated unconformably by undeformed layers, can be traced for tens of meters, indicating that they were formed by seismic shaking triggered by LTF activity. The deformation of the banded travertine layers is attributed to the combined effects of seismic shaking, liquefaction, and fluidization, and it can be related to a paleo earthquake event with a magnitude of MS ​> ​5. The U-series ages obtained from the banded travertine deposits perturbed by the earthquakes are in the range of 130.59–112.94 ka, indicating an important fault-assisted neotectonic activity that occurred during the Middle–Late Pleistocene. Analysis of such structures, in combination with the use of U-series dating methods, can yield a reliable timing of neotectonic activity and provide new evidence for understanding the seismotectonic setting of the Litang area.

ObjectiveThe Valsalva maneuver is the most sensitive provocative maneuver for patent foramen ovale detection. However, nearly half of patients are unable to perform the Valsalva maneuver well. The aim of this study was to investigate the mechanism of action of calf muscle pump tensing (TENSE) as a novel patent foramen ovale (PFO) provocative maneuver and to evaluate the diagnostic value for PFO and the effect on right-to-left shunt volume compared with the Valsalva maneuver.MethodsThis study prospectively investigated 171 patients who were highly suspected to have PFO clinically. Five patients with atrial septal defects newly diagnosed on transesophageal echocardiography (TEE) were excluded. 166 patients were injected with agitated saline under three provocative maneuvers: Valsalva maneuver, TENSE, and Valsalva + TENSE combined maneuver. The patients were divided into the effective Valsalva group (n = 93) and ineffective Valsalva group (n = 73) according to whether they could perform an effective Valsalva maneuver. TENSE consisted of the straightening of both lower limbs, and when the right atrium was filled with microbubbles, the patient performed instantaneous ankle dorsiflexion movements while maintaining dorsiflexion for 3–5 s.ResultsOverall, the PFO detection rate of the Valsalva + TENSE combined maneuver (78 [50.1%]) was significantly higher than that of the Valsalva maneuver (51 [30.7%]) and TENSE maneuver (57 [34.3%]) (P < 0.001). In the patients who were able to perform an effective Valsalva maneuver, the PFO detection rate by TENSE was not significantly different from that by the Valsalva maneuver (Valsalva 37/93 [39.8%] vs. TENSE 31/93 [33.3%], P > 0.05), while for the patients who performed an ineffective Valsalva maneuver, the PFO detection rate by the TENSE maneuver was higher than that by the Valsalva maneuver (TENSE 26/73 [35.6%] vs. Valsalva14/73[19.2%], P = 0.017).ConclusionTENSE is a simple and effective provocative maneuver in the diagnosis of PFO using TEE and can assist the Valsalva maneuver. For patients who cannot perform an effective Valsalva maneuver, TENSE can be an alternative to the Valsalva maneuver to some extent.

this study was to explore the diagnosis of septic shock patients with Escherichia coli (E. coli) infection based on cardiovascular color Doppler ultrasound (CCDUS) images under the machine learning risk prediction mathematical model (risk prediction model). 120 septic shock patients with Escherichia coli (E. coli) infection, admitted to xxx hospital were selected as research subjects, and they were randomly divided into experimental group and control group, including 76 males and 44 females, with an average age of (45.47 ± 11.35) years old. The prediction model, random forest mathematical model (RF model), and feature combination were trained and applied in the CCDUS. The error rate, F1-score, and area under the curve (AUC) were compared. It was found that the prediction effect of the risk prediction model was better (P

The structure-sensitive activity of Pd catalysts in carbonylation reactions is an urgent problem to be explored. Herein, Pd nanocrystals with uniform particle sizes (2.3 nm, 3.4 nm, 5.0 nm and 6.7 nm) were produced by using PVP to regulate the growth of Pd nanoparticles. The catalytic carbonylation reaction showed a "volcanic curve" with the increase in Pd particle size, and the obtained Pd/CsHPMo catalyst with 5 nm Pd nanoparticles was preferred. The 5.0Pd/CsHPMo catalyst, with the strongest "SMSI effect", shows the strongest Pd-CsHPMo interaction, and the generated electron-deficient Pd active sites accelerated the cycle of Pd δ+ ↔ Pd (0), which endows its excellent catalytic efficiency. Meanwhile, DRIFTS in association with C 2 H 2 -TPD confirmed that the activation capacity of CO and C 2 H 2 gas varies greatly on various Pd particle-size centers. These results provide a method for the accurate design of high-performance carbonylation catalysts.