RESUMO
Background: Dexmedetomidine (Dex), as a new and highly selective α2 adrenergic receptor agonist, has been widely used in mechanically ventilated patients. In the present study, we used meta-analysis to study the effect of Dex on the prognosis of mechanically ventilated patients with sepsis. Methods: We searched PubMed, Cochrane clinical trial, EMBASE, Web of Science, and Chinese biomedical literature database to analyze relevant literature published from January 2000 to January 2021. We conducted the quality evaluation and data extraction for studies that met the inclusion criteria. RevMan 5.3 software was used to perform a meta-analysis of the 28-day mortality, hospital mortality, the length of ICU stay, and other adverse indicators. Results: Ten randomized controlled trials (RCTs) that met the inclusion criteria were finally included, including 9 RCTs in English and one in Chinese, with a total of 892 patients. Our meta-analysis results found that in mechanically ventilated patients with sepsis, Dex could significantly reduce the length of ICU stay (P=0.02), but did not reduce the patients' 28-day mortality (P=0.06), hospital mortality (P=0.17) and ventilator-free days (P=0.33). Furthermore, our meta-analysis results also found that Dex had no significant effect on the respiratory rate (P=0.53), heart rate (P=0.02), mean arterial pressure (P=0.63), the level of creatinine (P=0.82) and continuous renal replacement therapy (P=0.39) in mechanically ventilated patients with sepsis. Conclusion: In mechanically ventilated patients with sepsis, Dex can reduce the length of ICU stay, but which cannot reduce the 28-day mortality, hospital mortality, and ventilator-free days.
RESUMO
We built a tethered nanoparticle (TNP) model that is composed of a nanoparticle with a hydrophobic tethered polymer chain. The shape of the nanoparticle can be tuned from a pure rigid cube to a soft sphere, mimicking the increase of grafting density on the nanocube surfaces. With this model, we study the self-assembly of TNPs in dilute solution using a dissipative particle dynamics simulation technique, and especially focus on the influence of particle shape, tethered chain length, and grafting density on the self-assembly structures. Some intriguing aggregates such as spherical micelles, pearl-necklace-like structures, cubic columnar structures, handshake structures, core-shell-corona micelles, and four-patch micelles have been observed when varying the interactions between cubes and solvents and the lengths of tethered chain. Modifying the nanocube surface with some hydrophilic grafted chains helps the TNPs form small micelles. Increased steric repulsion due to chain overlapping at larger grafting densities results in shape transformation of the nanoparticle from a rigid cube to a soft sphere. In these cases, the self-assembled structures are characterized by the packing of nanoparticles on the micelle surface, and the typical packing mode turns from rectangular (typical for cubes) to hexagonal (typical for spheres).
