RESUMEN
Low-velocity shock wave-induced contraction and expansion of nanobubbles can be applied to biocarriers and microfluidic systems. Although experiments have been conducted to study the application effects, the dynamic behavior characteristics of nanobubbles remain unexplored. In this work, we utilize molecular dynamics (MD) simulations to investigate the dynamic behavior characteristics of nanobubbles influenced by low-velocity shock waves in a liquid argon system. The DBSCAN (Density-Based Spatial Clustering of Applications with Noise) machine learning method is used to calculate the equivalent radius of nanobubbles. Two statistical methods are then utilized to predict the time series changes in the equivalent radius of nanobubbles without rebound shock waves. The piston velocity is analyzed using the bisection method to obtain the critical impact states of the nanobubble. The results show that at the low velocity shock wave (piston velocity of 0.1 km s-1), the shock wave pressure is small, the non-vacuum nanobubbles contract and expand in a circular shape, and the gas particles inside the bubble are not dispersed. In contrast, the vacuum nanobubbles collapse directly. As the shock wave rebounds upon impact, it triggers periodic contraction and expansion of the nanobubbles. The predictions indicate that the equivalent radius will vary within a small range according to the pre-predicted values in the absence of the rebound shock wave. Nanobubbles are present in four critical impact states: dispersed gaps, multiple smaller bubbles, two split bubbles, and a concave bubble.
RESUMEN
Septic shock is the most serious complication of sepsis, leading to unacceptably high morbidity and mortality worldwide. Fluid resuscitation using crystalloids has become the mainstay of early and aggressive treatment of severe sepsis and septic shock, while increased daily fluid balances from day 2 until day 7 have been related with increased mortality. Recently, pharmacological management has been recommended to combine with appropriate fluid resuscitation for the treatment of septic shock. In this study, we compared the clinical efficacy of restricting volumes of resuscitation fluid strategy with or without intravenous infusion of ulinastatin (UTI) in treating patients with septic shock and additionally examined the patient's changes of the extravascular lung water index (EVLWI), pulmonary vascular permeability index (PVPI), systemic vascular resistance index (SVRI), cardiac function, lactic acid (LA) level, coagulation function, and renal function. The study included 182 patients with septic shock, among which 89 patients had undergone restricting volumes of resuscitation fluid strategy with intravenous infusion of UTI and 93 patients had undergone restricting volumes of resuscitation fluid strategy alone. It was found that patients with septic shock after restricting volumes of resuscitation fluid strategy with intravenous infusion of UTI showed an increased SVRI concomitant with declined PVPI and EVLWI, increased mean artery pressure (MAP), cardiac output (CO), left ventricular ejection fraction (LVEF), stroke volume (SV), and heart rate (HR), declined levels of cardiac troponin I (cTnI), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and C-reactive protein (CRP), reduced LA level along with shortened prothrombin time (PT) and partially activated thrombin time (PATT), and decreased levels of blood urea nitrogen (BUN), creatinine (Cr), and uric acid (UA) when comparable to those after restricting volumes of resuscitation fluid strategy alone (P < 0.05). We also observed fewer scores of the Acute Physiology and Chronic Health Evaluation (APACHE II) and the sequential organ failure assessment (SOFA) in patients undergoing restricting volumes of resuscitation fluid strategy with intravenous infusion of UTI than those undergoing restricting volumes of resuscitation fluid strategy alone (P < 0.05). According to the above data, it is concluded that UTI as an adjuvant therapy for restricting volumes of resuscitation fluid strategy in treating septic shock may decrease the LA level, attenuate the inflammatory response, reduce vascular permeability, prevent pulmonary edema, and restore cardiac and renal functions.