ABSTRACT
In this study, we propose a novel ion formation simulation method for electrospray ionization (ESI) and atmosphere pressure interface (API). In this method, not the sheer particle trajectory, but the evolution of droplets and the offspring of gaseous ions are introduced instead. For the first time, the dynamic droplet-to-ion transformation process in the API of ESI-MS is visualized. The results suggest that this model provides a better understanding of the ion evolution mechanism and we propose a way for mass spectrometer structure optimization and ion source parameter adjustment in new aspects.
ABSTRACT
Objective:To investigate the types, incidences, and clinical characteristics of shock in polytrauma patients at different stages after polytrauma.Methods:A retrospective study was conducted on polytrauma patients admitted to multiple trauma centers from June 2020 to December 2021. The inclusion criteria were patients >18 years old and treated due to polytrauma. Exclusion criteria included an admission time of more than 48 h after trauma, a history of malignancy, or metabolic, consumptive, and immunological diseases. The early stage was defined as the period of ≤48 h after polytrauma, and the middle stage was defined as the period between 48 h and 14 days. The patient’s medical history, clinical manifestations, laboratory tests, imaging examination, injury severity score (ISS), and Glasgow coma scale (GCS) were collected. The types, incidences, and clinical characteristics of shock in different stages after polytrauma were analyzed, according to the diagnostic criteria of each type of shock. The differences between the groups were compared by Student’s t test, χ2 test or Mann-Whitney U test. Results:The incidence of the early and middle stage shock after polytrauma were 73.1% and 36.4%, respectively, with statistically significant difference between stages ( P<0.01). There were significant differences in the incidence of hypovolemic shock (83.6% vs. 28.4%), distributed shock (13.7% vs. 80.9%) and cardiogenic shock (3.5% vs. 6.6%) between stages (all P<0.05). The incidence of obstructive shock (8.4% vs. 9.7%, P>0.05) was similar between stages. The incidence of undifferentiated shock was 1.6% and 1.2%, respectively. There were 9.5% patients with multifactorial shock in the early stage and 14.4% in the middle stage. Totally 7 combinations of multifactorial shock were found in different stages after polytrauma. In the early stage, the combination of HS and DS accounted the highest ratio (42.3%) and followed by HS and OS for 28.8%. In the middle stage, the combination of HS and DS was the most common (48.6%) and followed by DS and OS (24.3%). Conclusions:The incidence of shock in polytrauma patients is high. Different types of shock can occur simultaneously or sequentially. Therefore a comprehensive resuscitation strategy is significant to improve the success rate of treatment.
ABSTRACT
The stress monitoring of bolted connections is crucial in the evaluation of mechanical systems' structural health, and the ultrasonic method using TOF (Time of Flight) is considered promising in this application. However, the discrete nature of couplant layer characteristics can deteriorate the robustness of the ultrasonic method significantly. Here, for the purpose of deducting the coupling error, a compensating method of TOF is proposed. In this method, the components of the waves backscattering from bolt bearing surface within the temporal signal are filtered and utilized. The analytical coupling error correction model is established and the influences of the installation eccentricity upon the model are analyzed. Meanwhile, the proposed method is further verified by a finite element simulation and the results are consistent with the analytical derivations. Ultimately, the proposed method is experimentally validated and the scattering components are extracted from the pulse echo signal by using the synchrosqueezed wavelet transform. The results imply that, after being compensated by the proposed method, the stress measurement error decreased from 5% to 1%. This research provides a novel perspective in reducing the coupling error in a concise manner and is potential in improving the practicality of the ultrasonic bolt axial stress measurement methods.
