Bioflocs protects copper-induced inflammatory response and oxidative stress in Rhynchocypris lagowski Dybowski through inhibiting NF-κB and Nrf2 signaling pathways.

Copper (Cu) is an essential element in the metabolic process of humans and animals, but it can cause toxicity at high concentrations of exposure. Bioflocs has been proved to have antioxidant, immune-enhancing and anti-inflammatory properties. Here, the purpose of this study was to evaluate potential mechanisms and protective effects of bioflocs and Cu exposure on inflammatory response, oxidative stress and immune-related genes and protein expression in Rhynchocypris lagowski Dybowski. 360 healthy R. lagowski were irregularly distributed among 12 tanks (3 tanks per group, 30 fish per tank). The experiment was divided into two parts: the feeding experiment was carried out in the first eight weeks, followed by acute copper exposure for 96 h. Then we selected the stressed fish for experimental analysis. The results provided evidences that bioflocs protected the R. lagowski by inhibiting the accumulation of copper, the activity of immune enzymes and the expression of NF-κB signaling pathway related genes and proteins, and the activity of antioxidant enzymes and the expression of Nrf2 signaling pathway related genes. Overall, these findings suggest that bioflocs could regulate the activation of Nrf2 and protect acute copper exposure induced inflammatory response by inhibiting the NF-κB signaling pathway in R. lagowski.

Expiratory asynchrony.

Expiratory asynchrony is a universal phenomenon, and expiratory synchrony occurs only by chance. Expiratory asynchrony exists in all breath modes and has a significant impact on the patient's work of breathing and the weaning process. Advancements in ventilator designs and basic physiologic science could lead to the improvement of the expiratory asynchrony.

Estimation of cerebrospinal fluid pressure via lumbar epidural space by equilibration method.

By introducing water into the lumbar epidural space from a vertically held tube under gravity, we measured lumbar epidural pressure (EDP) when the water meniscus no longer declined. In principle, the pressure of either side of dura mater had become equal at this time which is referred to as the equilibrium point. EDP measured in this way was consistently 1-3 mmHg lower than lumbar cerebrospinal fluid pressure (CSFP) not only immediately after the equilibrium point, but also for 5 min after the equilibrium point had been reached. Both EDP and CSFP responded sensitively to the manipulations of CSFP during this period. We suggest that this method may provide a means to continuously monitor CSFP by EDP.

Expiratory asynchrony in proportional assist ventilation.

One of the proposed advantages of proportional assist ventilation (PAV) has been the automatic synchrony between the end of the patient's inspiratory effort and the ventilator cycle (i.e., expiratory synchrony). However, recent clinical studies have shown a prolonged ventilator inspiratory time or even a "runaway" phenomenon with the normal use of PAV. We hypothesize that control-system delay may account for this, because in reality there is always some degree of delays between control-system's input and output in all ventilators. Computer simulation study to date has not taken into account the potential effect of control-system delay on expiratory synchrony. We therefore created a computer model in which the parameter of control-system delay time was introduced. We found that significant expiratory asynchrony may occur with this more realistic model of PAV. The ventilator flow termination may fall behind the completion of the patient inspiration by as long as 0.33 seconds under the selected simulation conditions. The inspiratory termination delay time is in proportion to the control-system delay time, the respiratory time constant, and the assist gain settings. In conclusion, this model indicates that due to the unavoidable control-system delay in the ventilators, expiratory asynchrony may be an inherent shortcoming associated with PAV.