Prediction of binding affinity and enthalpy of CB7 with alkaloids by attach-pull-release molecular dynamics simulations study.

Host-guest complex has attracted much attention because of their fantastic capability. Accurate prediction of their binding affinity and enthalpy is essential to the rational design of guest molecules. The attach-pull-release (APR) method proposed by Henriksen et al. (J. Chem. Theory Comput., 2015, 11:4377.) shows good prediction capability of binding affinity especially for host-guest system. In order to further evaluate the performance of APR method in practice, we have conducted the calculations on the macrocycle cucurbit [7]urils (CB7) encapsulated with four structurally similar alkaloids (berberine, coptisine, epiberberine and palmatine) with two force fields (GAFF and GAFF2) and three water models (TIP3P, SPC/E and OPC). Compared to the experimental data, the calculation by the combination of GAFF2 and SPC/E force field presents the best performance, of which the Pearson correlation coefficients (R2) is 0.95, and the root-mean-square-deviation is 3.04 kcal/mol. While the predictions from GAFF force field all overestimated the binding affinity, suggesting a systematic error may be involved. Comparison of calculation also indicates that the accuracy of prediction was susceptible to the combination of force field. Therefore, it would be necessary to repeat the simulation with different combination of force fields in practice.

Correction: Enhanced photoluminescence stability and internal defect evolution of the all-inorganic lead-free CsEuCl3 perovskite nanocrystals.

Correction for 'Enhanced photoluminescence stability and internal defect evolution of the all-inorganic lead-free CsEuCl3 perovskite nanocrystals' by Yalei Gao et al., Phys. Chem. Chem. Phys., 2022, 24, 18860-18867, https://doi.org/10.1039/D2CP01374F.

Enhanced photoluminescence stability and internal defect evolution of the all-inorganic lead-free CsEuCl3 perovskite nanocrystals.

Perovskite materials are prominent candidates for many high-performance optoelectronic devices. The rare-earth lead-free CsEuCl3 perovskite nanocrystals are extremely unstable, which makes it very difficult to study their physicochemical properties and applications. Herein, we improved the stability of rare-earth based CsEuCl3 nanocrystals by employing a silica-coating for the first time. Simultaneously, the naturally formed "hollow" regions with an obviously blue-shifted PL emission were first observed inside the CsEuCl3 nanocrystals during the period of storage. Density functional theory (DFT) calculations showed that the formed "hollow" regions are due to the internal defect evolution in the perovskite lattice, which is also responsible for the increase of the bandgap and the blue-shift of emission. Additionally, the rapid decline of luminescence is probably due to the nanocrystals' final cracking with the expansion of the "hollow" regions. This work helps to understand the relationship between defects and luminescence properties, and provides guidance for the design of more stable lead-free perovskite nanocrystals.

Assessment of risk factors for postoperative cognitive dysfunction after coronary artery bypass surgery: a single-center retrospective cohort study.

AIM: To find out risk factors for postoperative cognitive dysfunction (POCD) after coronary artery bypass grafting (CABG), and to provide basis for clinical prevention of POCD. A total of 88 patients who underwent CABG were surveyed with Telephone Questionnaire (TICS-M) for their cognitive impairment after 3, 7, 21, 90, 180 days post-surgery. The occurrence of POCD was diagnosed by Neuropsychological Battery which included Vocabular Learning Test (VLT), Wisconsin Card Sorting Test (WCST), Trail Making Test (TMT) and Symbol Digit Modalities Test (SDMT). The preoperative, intraoperative and postoperative risk factors were assessed by the χ2 or t test. Multivariate analysis was used to study the correlation between the risk factors and the occurrence of POCD. Age, aortic plaque, carotid artery stenosis, cerebrovascular disease, anesthesia time, the rate of decline in intraoperative hemoglobin concentration (ΔHb) and systemic inflammatory response syndrome (SIRS) score on postoperative day 2 had statistically significant (P<0.05) influence on the occurrence of POCD. Aortic plaque, carotid artery stenosis, anesthesia time and SIRS score (odds ratio (OR) value > 1, P<0.05) are the risk factors for POCD. The incidence of day-21 and -180 POCD was approximately 26.1 and 22.7%, respectively.

Chronic unpredictable stress exacerbates surgery-induced sickness behavior and neuroinflammatory responses via glucocorticoids secretion in adult rats.

METHODS: Sprague-Dawley adult male rats (12-14 weeks old) were exposed to 14-day CUS and then subjected to partial hepatectomy 24 h after the last stress session. The rats were pretreated with an antagonist of the glucocorticoids (GCs) receptor RU486 (30 mg/kg, i.p.) 1 h prior to stress exposure. The behavioral changes were evaluated with open field test and elevated plus-maze test. The hippocampal cytokines interleukin (IL)-1ß and IL-6 were measured on postoperative days 1, 3 and 7. Ionized calcium binding adaptor protein (Iba)-1, microglial M2 phenotype marker Arg1, brain derived neurotrophic factor (BDNF) and CD200 were also examined at each time point. RESULTS: CUS exacerbated surgery-induced sickness behavior. Exposure to CUS alone failed to alter the levels of pro-inflammatory cytokines in the brain. However, CUS exaggerated surgery-induced pro-inflammatory cytokines expression (e.g. IL-1ß and IL-6) and upregulated the levels of Iba-1 on postoperative days 1 and 3. An additional significant decreased BDNF, CD200 and a lower level of Arg1 were also observed in the stressed rats following surgical procedure. Pretreatment with RU486 blunted the potentiating effects of CUS on surgery-induced sickness behavior and neuroinflammatory responses. CONCLUSION: Chronic unpredictable stress enhanced surgery-induced sickness behavior and neuroinflammatory responses. Stress-induced GCs played a pivotal role in enhancing surgery-induced neuroinflammatory processes by modulation of microglia functions.

Prior stressor exposure delays the recovery of surgery-induced cognitive impairment and prolongs neuroinflammation in aged rats.

UNLABELLED: Increasing evidence indicates that stress potentiates pro-inflammatory response to a subsequent peripheral immune challenge. The present study investigated if prior exposure to inescapable tailshock (IS) delayed the recovery of surgery-induced spatial learning and memory impairment and prolonged hippocampus interleukin (IL)-1ß and IL-6 expression. METHODS: A total of 192 aged rats were trained with Morris water-maze (MWM) for 6 consecutive days. A single session of inescapable tailshock was performed on day 6 after training. Then, the rats subjected to partial hepatectomy. Hippocampal-dependent spatial learning and memory were assessed on postoperative days 1, 3 and 7. The cytokines IL-1ß and IL-6 and ionized calcium binding adaptor protein (Iba)-1 were measured at each time point. Cluster of differentiation 200 (CD200) was also measured to explore potential mechanisms of glial cell activation. RESULTS: Exposure of IS alone failed to affect the latency to platform and increase hippocampal cytokine levels at each time point. However, IS alone significantly increased the expression levels of Iba-1. A prolonged latency and additional significant increase in hippocampal levels of IL-1ß and IL-6 were observed when partial hepatectomy was performed in aged rats exposed to IS 24h later. The combination of IS and surgical trauma dramatically upregulated the levels of Iba-1 and significantly decreased the expression of CD200. CONCLUSION: IS alone failed to induce cognitive deficits and increase pro-inflammatory cytokines expression. However, IS delayed the recovery of surgery-induced spatial learning and memory impairment and prolonged pro-inflammatory response to the subsequent surgery challenge.