Theoretical and kinetic study of the H-atom abstraction reactions by H atom from alkyl cyclohexanes.

Reaction kinetics of hydrogen atom abstraction from six alkyl cyclohexanes, methyl cyclohexane (MCH), ethyl cyclohexane (ECH), n-propyl cyclohexane (nPCH), iso-propyl cyclohexane (iPCH), sec-butyl cyclohexane (sBCH) and iso-butyl cyclohexane (iBCH), by the H atom are systematically studied in this work. The M06-2X method combined with the 6-311++G(d,p) basis set is used to perform geometry optimization, frequency analysis and zero-point energy calculations for all species. The intrinsic reaction coordinate (IRC) calculations are performed to confirm the transition states connecting the reactants and products correctly. One-dimensional hindered rotors are used to treat the low frequency torsional models with potentials scanned at the M06-2X/6-31G level of theory. Electronic single-point energy calculations for all reactants, transition states, and products are performed at the QCISD(T)/CBS level of theory. High-pressure limiting rate constants of 39 reaction channels are obtained using conventional transition state theory with asymmetric Eckart tunneling corrections in the temperature range 298.15-2000 K. Reaction rate rules for H-atom abstraction by the H atom from alkyl cyclohexanes on primary, secondary and tertiary carbon sites on both the side chain and ring are provided. The obtained rate constants are given by the Arrhenius expression in the temperature range 500-2000 K, which can be used for the combustion kinetics model development for alkyl cyclohexanes.

Transcatheter aortic valve replacement for aortic regurgitation: a systematic review and meta-analysis.

The efficacy and safety of new-generation devices (NGDs) for severe aortic regurgitation (AR) have mostly been based on single-arm studies with limited sample sizes. Our goal was to summarize the current evidence on NGDs and compare the safety and efficacy of 'off-label' and 'on-label' devices in NGDs. We searched MEDLINE, Embase, Cochrane Library, and Scopus for articles on transcatheter aortic valve replacement in patients with AR. A total of 31 studies that included 1851 patients were identified through April 2023. Among these, 1067 (57.6%) patients received treatment with 'on-label' devices (JenaValve and J-Valve). For NGDs, the total device success rate at 30 days was 94.5% (on-label: 97.8%, off-label: 89.9%; P < 0.001), the all-cause mortality was 4.2% (on-label: 2.6%, off-label: 5.1%; P = 0.006), permanent pacemaker implantation (PPI) was 8.8% (on-label: 6.9%, off-label: 18.4%; P < 0.001), and the rate of greater-than-mild paravalvular leak (PVL) was 1.2% (on-label: 0.9%, off-label: 3.8%; P = 0.003). On-label devices showed significantly better safety and efficacy in terms of the success rate, PPI, greater-than-mild PVL, and 30 day mortality than off-label devices.

Synergistic effects of the bimetallic Ni-Fe systems and their application in the reductive amination of polyether polyols.

We report the synthesis of xNi-yFe/γ-Al2O3 catalysts which were applied to the reductive amination of polypropylene glycol (PPG) for the preparation of polyether amine (PEA). The catalysts were characterized by N2-sorption, X-ray diffraction, H2-temperature programmed reduction, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy to reveal the synergistic effect of the bimetallic Ni-Fe-loaded catalysts. It was found that in the reductive amination of PPG to PEA, the conversion and product selectivity of the reaction were closely related to the types of active centers of the catalyst. In particular, the surface Ni0 content increased by adding Fe as a promoter, with a maximum Ni0 content on the 15Ni-7.5Fe/Al2O3 catalyst, which also led to the highest conversion rate (>99%). In addition, no deactivation was observed after three cycles of reaction carried out by the catalyst.

Differential expression profiles and functional analysis of long non-coding RNAs in calcific aortic valve disease.

AIM: To evaluate the expression profile of long non-coding RNAs (lncRNAs) in calcific aortic valve disease (CAVD) and explore their potential mechanism of action. METHODS: The gene expression profiles (GSE153555, GSE148219, GSE199718) were downloaded from the Gene Expression Omnibus (GEO) database and FastQC was run for quality control checks. After filtering and classifying candidate lncRNAs by differentially expressed genes (DEGs) and weighted co-expression networks (WGCNA) in GSE153555, we predicted the potential cis- or trans-regulatory target genes of differentially expressed lncRNAs (DELs) by using FEELnc and established the competitive endogenous RNA (ceRNA) network by miRanda, more over functional enrichment was analyzed using the ClusterProfiler package in R Bioconductor. The hub cis- or trans-regulatory genes were verified in GSE148219 and GSE199718 respectively. RESULTS: There were 340 up-regulated lncRNAs identified in AS group compared with the control group (|log2Fold Change| ≥ 1.0 and Padj ≤ 0.05), and 460 down-regulated lncRNAs. Based on target gene prediction and co-expression network construction, twelve Long non-coding RNAs (CDKN2B-AS1, AC244453.2, APCDD1L-DT, SLC12A5-AS1, TGFB3, AC243829.4, MIR4435-2HG, FAM225A, BHLHE40-AS1, LINC01614, AL356417.2, LINC01150) were identified as the hub cis- or trans-regulatory genes in the pathogenesis of CAVD which were validated in GSE148219 and GSE19971. Additionally, we found that MIR4435-2HG was the top hub trans-acting lncRNA which also plays a crucial role by ceRNA pattern. CONCLUSION: LncRNAs may play an important role in CAVD and may provide a new perspective on the pathogenesis, diagnosis, and treatment of this disease. Further studies are required to illuminate the underlying mechanisms and provide potential therapeutic targets.

Thrombosis origin identification of cardioembolism and large artery atherosclerosis by distinct metabolites.

BACKGROUND: The diagnosis of cerebral thrombosis origin is challenging and remains unclear. This study aims to identify thrombosis due to cardioembolism (CE) and large artery atherosclerosis (LAA) from a new perspective of distinct metabolites. METHODS: Distinct metabolites between 26 CE and 22 LAA origin thrombi, which were extracted after successful mechanical thrombectomy in patients with acute ischemic stroke in the anterior circulation, were analyzed with a ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) system. Enriched metabolic pathways related to the metabolites were identified. Least absolute shrinkage selection operator regression analyses and a filtering method were used to select potential predictors. Furthermore, four machine learning classifiers, including decision tree, logistic regression, random forest (RF), and k means unsupervised classification model, were used to evaluate the predictive ability of the selected metabolites. RESULTS: UPLC-QTOF-MS analysis revealed that levels of 88 and 55 metabolites were elevated in LAA and CE thrombi, respectively. Kyoto Encyclopedia of Genes and Genomes analysis revealed a significant difference between the pathways enriched in the two types of thrombi. Six metabolites (diglyceride (DG, 18:3/24:0), DG (22:0/24:0), phytosphingosine, galabiosylceramide (18:1/24:1), triglyceride (15:0/16:1/o-18:0), and glucosylceramide (18:1/24:0)) were finally selected to build a predictive model. The predictive RF model was confirmed to be the best, with a satisfactory stability and prediction capacity (area under the curve=0.889). CONCLUSIONS: Six metabolites as potential predictors for distinguishing between cerebral thrombi of CE and LAA origin were identified. The results are useful for understanding the pathogenesis and for secondary stroke prevention.

Clinical Significance and Influencing Factors of Microvascular Tissue Reperfusion After Macrovascular Recanalization.

The relevance of impaired microvascular tissue reperfusion despite successful macrovascular angiographic reperfusion (no-reflow) in acute ischemic stroke (AIS) remains controversial. In this study, we aimed to investigate the impact of tissue optimal reperfusion (TOR) and its influencing factors. From December 1, 2020 to December 1, 2021, AIS patients with successful recanalization (modified Thrombolysis in Cerebral Infarction score [mTICI] ≥ 2b) after mechanical thrombectomy (MT) were retrospectively reviewed. Computed tomography perfusion was performed before and after MT. Successful reperfusion was assessed by TOR, defined as > 90% reduction of the Tmax > 6 s lesion volumes between baseline and early follow-up perfusion profiles. The impact of TOR on functional outcomes after successful recanalization and influencing factors for TOR were both investigated. Sixty-three patients were included, including 44 cases in the TOR group and 19 cases in the non-TOR group. The TOR group had a higher rate of favorable outcome (aOR 4.366, 95%CI 1.159-16.445, p = 0.030) and NIHSS improvement (aOR 5.089, 95%CI 1.340-19.322, p = 0.017) than the non-TOR group. Multivariable logistic regression showed baseline glucose (OR 0.648, 95%CI 0.492-0.854, p = 0.002) and mTICI 2c/3 (OR 10.984, 95%CI 2.220-54.343, p = 0.003) predicted TOR in model 1; in model 2, postoperative glucose (OR 0.468, 95%CI 0.278-0.787, p = 0.004) and mTICI 2c/3 (OR 9.436, 95%CI 1.889-47.144, p = 0.006) were predictive. TOR was strongly associated with good functional outcomes after successful recanalization of MT. Higher mTICI grade and lower perioperative glucose level may predict microvascular tissue reperfusion.

Clinical evidence comparing bridging and direct endovascular thrombectomy: progress and controversies.

Clinical evidence comparing bridging endovascular thrombectomy (bEVT) with intravenous thrombolysis and direct endovascular thrombectomy (dEVT) without thrombolysis for patients with acute ischemic stroke (AIS) presented directly to an EVT-capable center is overwhelming but inconsistent. This study aimed to analyze the progress and controversies in clinical evidence based on current meta-analyses. Three databases, including MEDLINE, EMBASE, and the Cochrane Library, were searched. Relevant data were extracted and reviewed from the pooled studies. The Assessment of Multiple Systematic Review (AMSTAR-2) was used for quality assessment. Twenty-five meta-analyses were finally included. There were 56% (14/25) from Asian countries, 20% (5/25) from North America, and 24% (6/25) from Europe. The majority (72%, 18/25) of evidence arose in a short period from 2020 to 2022 with the serial publication of four randomized controlled trials (RCTs). Among the 25 meta-analyses, 11 pooled at least three RCTs but there is substantial overlap among seven (five recruited the same four RCTs solely and two recruited the same three RCTs solely). Meanwhile, quality rating based on AMSTAR-2 showed 16 'high' rated studies (64%). For functional independence, 40% (10/25) of studies favored bEVT and 60% showed neutral results. For symptomatic intracerebral hemorrhage, most studies (82.6%, 19/23) showed no significant difference. Non-RCT studies contributed to evidence favoring bEVT. Current RCTs provide an update of clinical evidence comparing bEVT and dEVT. However, they simultaneously contribute to an unnecessary overlap among studies. Contemporary observational studies demonstrated different but possibly confounded evidence. Thus, this issue still requires more clinical evidence under standard procedures.

Outcomes after endovascular thrombectomy for acute ischemic stroke patients with active cancer: A systematic review and meta-analysis.

Background: Active cancer (AC) is a known risk factor for stroke and a common comorbidity among patients being considered for treatment with endovascular thrombectomy (EVT). This systematic review and meta-analysis aimed to evaluate the current evidence for the feasibility, efficacy, and safety of EVT for patients with AC. Methods: MEDLINE, EMBASE, and the Cochrane Library were searched for relevant randomized controlled trials (RCTs) and observational studies which met the inclusion criteria for EVT in patients with AC. Studies were excluded due to the mismatch of data format, article type, and group design. The risk of bias was assessed through different scales according to the study design. I 2 statistics were used to evaluate the heterogeneity. Funnel plots were used to evaluate publication bias. Results: A total of six studies and 3,657 patients were included. Compared to without active cancer (WC) patients, patients with AC had a significantly higher proportion of in-hospital mortality (OR 3.24; 95% CI, 1.03-10.15). The estimated rate of favorable outcome of six studies was lower in patients with AC than in patients with WC (OR 0.47; 95% CI, 0.35-0.65). For 90-day mortality of four studies, the AC group had a higher proportion when compared with the WC group (OR 3.87; 95% CI, 2.64-5.68). There was no difference between rate of six studies of successful recanalization (OR 1.24; 95% CI, 0.90-1.72) and four studies of symptomatic ICH (OR 1.09; 95% CI, 0.61-1.97) comparing AC and WC. Conclusion: Patients with AC are less likely to have a favorable outcome and have a higher risk of mortality after EVT. Further studies are warranted for this unique patient population.

Postoperative neutrophil-lymphocyte ratio predicts unfavorable outcome of acute ischemic stroke patients who achieve complete reperfusion after thrombectomy.

Purpose: Only approximately half of anterior circulation large vessel occlusion (LVO) patients receiving endovascular treatment (EVT) have a favorable outcome. The aim of this study was to explore the association of dynamic inflammatory markers (i.e., neutrophil to lymphocyte ratios, NLR, measured at different times after EVT) as well as other potential influencing factors with unfavorable outcome among acute ischemic stroke (AIS) patients who achieved complete reperfusion after EVT. Methods: Patients treated with EVT for LVO between January 2019 to December 2021 were prospectively enrolled. Complete reperfusion was defined as modified thrombolysis in cerebral infarction (mTICI) grade 3. A modified Rankin scale at 90 days (mRS90) of 3-6 was defined as unfavorable outcome (i.e., futile reperfusion). A logistic regression analysis was performed with unfavorable outcome as a dependent variable. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were then used to determine the diagnostic values of NLR and other relevant factors. Results: 170 patients with complete reperfusion (mTICI 3) were included in this study. Unfavorable outcome was observed in 70 (41.2%). Higher NLR within 24h (p=0.017) and at 3-7d (p=0.008) after EVT were an independent risk factors for unfavorable outcome at 3 months. In addition, older age, higher NIHSS scores, poor collaterals, and general anesthesia were independent predictors of unfavorable outcomes. When accounting for NLR, the diagnostic efficiency improved compared to conventional characteristics. Conclusion: Our findings suggest that advanced age, increased stroke severity, poor collaterals, general anesthesia, and NLR are independent predictors for an unfavorable clinical outcome following complete reperfusion after EVT. Neuroinflammation may merit particular attention in future studies.

[Development of bio-jet fuel production technology: a review].

Due to the large amount of greenhouse gas emissions and the high dependence on fossil fuels, the sustainable development of aviation industry has attracted worldwide attention. Bio-jet fuel is considered to be a promising alternative to traditional aviation fuel. This article summarizes the representative technological route, development status, opportunities and challenges faced by the development of bio-jet fuel industry. So far, several bio-jet fuel production technologies have been certified by the American Society for Testing and Materials (ASTM). Hydroprocessed esters and fatty acids is currently the most mature process that can be fully commercialized. Considering economic characteristics and technology maturity, Fischer-Tropsch is promising in near term.

Highly Efficient Hydroisomerization of Endo-Tetrahydrodicyclopentadiene to Exo-Tetrahydrodicyclopentadiene over Pt/HY.

The fast deactivation caused by serious formation of coke is a major challenge in catalytic isomerization of endo-tetrahydrodicyclopentadiene (endo-THDCPD) into exo-tetrahydrodicyclopentadiene (exo-THDCPD) over the HY zeolite. In order to suppress the coke formation for the isomerization process, the conventional HY zeolite was modified with Pt at 0.3 wt %. Then, the hydroisomerization of endo-THDCPD into exo-THDCPD was evaluated over a fixed-bed reactor. The catalytic stability of Pt/HY was greatly enhanced in comparison to that of the HY zeolite. The Pt/HY catalyst provided 97% endo-THDCPD conversion and 96% selectivity for exo-THDCPD without deactivation after 100 h. Moreover, the formation mechanism of coke on the HY zeolite during the isomerization process was proposed based on the results of the coke analysis. It was indicated that the coke was generated from the oligomerization and condensation of olefin species, which originated from the ß-scission reaction or hydride transfer reaction of intermediates. The lower coke formation over Pt/HY was attributed to the lower amount of coke precursors, which could be hydrogenated by activated H2 over Pt sites. Therefore, Pt on Pt/HY and H2 were two crucial factors in efficiently enhancing the catalytic stability of the HY zeolite for this isomerization reaction.