In catalytic asymmetric reactions, the formation of chiral molecules generally relies on a direct chirality transfer (point or axial chirality) from a chiral catalyst to products in the ...stereo-determining step. Herein, we disclose a transient-axial-chirality transfer strategy to achieve asymmetric reaction. This method relies on transferring point chirality from the catalyst to a dirhodium carbene intermediate with axial chirality, namely a transient-axial-chirality since this species is an intermediate of the reaction. The transient chirality is then transferred to the final product by C(sp
)-H functionalization reaction with exceptionally high enantioselectivity. We also generalize this strategy for the asymmetric cascade reaction involving dual carbene/alkyne metathesis (CAM), a transition-metal-catalyzed method to access chiral 9-aryl fluorene frameworks in high yields with up to 99% ee. Detailed DFT calculations shed light on the mode of the transient-axial-chirality transfer and the detailed mechanism of the CAM reaction.
Human umbilical cord mesenchymal stem cell (hucMSC)-derived exosomes are recognized as novel cell-free therapeutic agents for inflammatory bowel disease (IBD), a condition caused by dysregulated ...intestinal mucosal immunity. In this event, macrophage pyroptosis, a process of cell death following the activation of NLRP3 (NOD-like receptor family, pyrin domain-containing 3) inflammasomes, is believed to partially account for inflammatory reactions. However, the role of macrophage pyroptosis in the process of hucMSC-derived exosomes alleviating colitis remains unknown. This study aimed at exploring the therapeutic effect and mechanism of hucMSC-derived exosomes on colitis repair.
In vivo, we used BALB/c mice to establish a dextran sulfate sodium (DSS)-induced colitis model and administrated hucMSC-derived exosomes intravenously to estimate its curative effect. Human myeloid leukemia mononuclear (THP-1) cells and mouse peritoneal macrophages (MPMs) were stimulated with lipopolysaccharides (LPS) and Nigericin to activate NLRP3 inflammasomes, which simulated an inflammation environment in vitro. A microRNA mimic was used to verify the role of miR-378a-5p/NLRP3 axis in the colitis repair.
hucMSC-derived exosomes inhibited the activation of NLRP3 inflammasomes in the mouse colon. The secretion of interleukin (IL)-18, IL-1β, and Caspase-1 cleavage was suppressed, resulting in reduced cell pyroptosis. The same outcome was observed in the in vitro cell experiments, where the co-culture of THP-1 cells and MPMs with hucMSC-derived exosomes caused decreased expression of NLRP3 inflammasomes and increased cell survival. Furthermore, miR-378a-5p was highly expressed in hucMSC-derived exosomes and played a vital function in colitis repair.
hucMSC-derived exosomes carrying miR-378a-5p inhibited NLRP3 inflammasomes and abrogated cell pyroptosis to protect against DSS-induced colitis.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The effect of several parameters on the recovery of silicon dioxide from calcined boron mud（CBM）such as stirring speed, temperature, sodium silicate concentration, and carbonation time was studied. ...The recovery of silicon dioxide is 88 % when the stirring speed is450 r min-1, temperature is 60 °C, sodium silicate concentration is 1 mol L-1, and the carbonation time is 6 h.The effect of carbonation time on the recovery of silicon dioxide is divided into three kinetic regimes, and the carbonation process of sodium silicate solution follows a second-order reaction based on the double-film theory model. The apparent rate constant of the three kinetic regimes is 0.064, 3.178, and 1.130 L h mol-1, respectively.The amorphous SiO_2 products obtained by carbonating the purified solution have 99.6 % purity and are spherical with diameters of about 100 nm.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Long-term streamflow forecast is of great significance for water resource application and management. However, accurate monthly streamflow forecasting is challenging due to its non-stationarity and ...uncertainty. Time series analysis methods have been proved to perform well in stationary time series forecasting, which can be derived from decomposition of the non-stationary sequence. As common decomposition methods in time domain, Empirical Mode Decomposition (EMD) and Ensemble Empirical Mode Decomposition (EEMD) are selected to decompose the components with different time-scale characteristics in the original hydrological time series in this study. The derived components are proved to be stationary by the stationarity test. Thus, Autoregressive Integrated Moving Average (ARIMA) model, a simple and effective time series analysis method, is used to forecast the components. A hybrid EMD/EEMD-ARIMA model is proposed in this study for long-term streamflow forecasting, which is applied to the upper stream of the Yellow River. The original daily streamflow time series of six years at the Tangnaihai station are firstly decomposed by EMD/EEMD into several stationary or simple non-stationary sub-series to explore detailed data information with different time scales. ARIMA models with appropriate parameters are then established for each subsequence to forecast the stream flow of the next year. Predicted ten-day and monthly stream flow is finally obtained combing the predictions of all the components. The EMD-ARIMA hybrid model performs best in forecasting high and moderate value of streamflow and fits best with the observation compared with EEMD-ARIMA and ARIMA models. The results not only verify the effectiveness of the proposed hybrid EMD/EEMD-ARIMA model in exploiting comprehensive information to improve the prediction but also indicate that the EMD-ARIMA model with end points disposal performs the best and can be used for long-term hydrological forecasting.
In this paper, quaternary 8-（1-acylethene-l-yl）-13-methylcoptisine chlorides targeting thioredoxin reductases （TrxRs） were designed to test the growth inhibitory activity against human cancer cell ...lines and the effect on viability of the normal intestinal epithelial cell-6 （IEC-6） in vitro and to evaluate structure-activity relationship （SAR）. The introduced α, β-unsaturated ketone groups at C-8 consisting of n-alkanoyls possessing five to ten carbons or aroyls or cyclohexylcarbonyl increased the tested activity against the target cancer cell lines. By and large, this type of improvement was increasingly graced by the elongation of the aliphatic chain of the n-alkanoyls in the range of less than ten carbon atoms. The relatively more polar l-acylethene-l-yls displayed no effect on improving the activity. All the explored aroyls showed significant effect on improving the activity of the target compounds against the tested cancer cell lines with no SAR being observed, The findings of this study suggested that oilwater partition coefficient of the test compounds was one of the key factors impacting the target activity against the tested cancer cell lines. At the concentration of 10 μmol/L, except for the compounds with n-all（anoyls possessing seven or more carbons or with α-naphthoyl, none of the other compounds displayed obvious cytotoxicity on normal IEC-6 cell when co-incubated. The survival rate of IEC-6 cell ranged from 75% to 100% for the noncytotoxic compounds.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
AIM：To investigate the intestine and body development of intrauterine growth retardation（IUGR）rats under early different protein diet and to analyze the correlation between leptin and intestine and ...body development．
METHODS：An IUGR rat model was established by food restriction of pregnant female rats．Fifty-six neonatal IUGR rats and 24 neonatal normal rats were randomly divided into normal control group（Cgroup），IUGR model group （scgroup），low protein diet IUGR group（SL group），and high protein diet IUGR group（SH group）．Eight rats were killed per group at wk 0，4，and 12．Serum leptin，body weight（BW），body length（BL），intestinal weight（IW），intestinal length（IL），andintestinal disaccharidase（including lactase，maltase，and saccharase） were detected．
RESULTS：BW（4．50±0．41g），BL（5．96±0．40cm），IW（0．05±0．01g），and IL（15.9±2．8cm）in neonatal IUGR rats were much lower than those in Cgroup（6．01±0．55g，6．26±0．44cm，0．10±0．02g，21.8±2．7cm，P〈0．05），while intestinal lactase and maltase activities were higher than those in Cgroup．SH group showed the fastest catch up growth and their BW，BL，IW，and IL reached the Cgroup level at wk 4．SC group showed relatively slower catch up growth than SH group，and their BW，BL，IW did not reach the Cgroup level at wk 4．SL group did not show intestine and body catch up growth．Intestinal maltase 344±33μmol／（min·q）and saccharase activities138±32μmol／（min·g）in SL group were both markedly lower than nose in C group 751±102，258±271μmol／（min·g），P〈0．05．There were no significant difierences in lactase activities at wk 4 and disaccharidase activities at wk 12 among all groups（P〈0．05）．The leptin level in SL group（0．58±0．12ng／mL） was the highest in all groups，and much lower in SH group（0．21±0．03ng／mL） than that in any other IUGR groups at wk 4（P〈0．05）．Leptin was negatively related to BW （r=-0．556，P=0．001），IW（r=-0．692，P=0．001） and IL（r=-0．738，P=0．000）at wk 4，while no correlation was found at wk 12．
CONCLUSION：High protein diet is a reasonable early nutritional mode to IUGR rats in promoting intestine and body catch up growth．
To mitigate the level of blast-induced vibrations, the time-delay experiments involved 5 delay intervals, 8 holes and 11 monitoring stations, were undertaken in a newly constructed underground mine. ...The method of instantaneous energy based on the empirical mode decomposition (EMD) was adopted to identify the actual delay times from the near-field accelerations. Then the Theil-Sen regression was adopted to analyze the vibration attenuation. Based on the drawbacks of the field experiments due to various unpredictable factors, the blast damage model was further employed to make a comprehensive understanding of the effects of delay times. The signature invoked the average waveform of multiple holes in the experimental 75 ms case, then a group of fluctuating signature waveforms were generated from the Monte Carlo scheme based on waveform comparison between the measured and the signature. Upon completion of the model verification, the number of delays was examined within four delay intervals, and 25 delays were selected to figure out the effects of delay times and delay errors. The results state that the peak particle velocity (PPV) and average frequency (AF) are insensitive to delay times irrespective of delay errors, except short delay times. The vibration dominant frequency (DF) is mainly contributed by idea delay times and delay errors, and the optimal delay interval is half of the dominant period, which is only effective to improve DFs at a target location. The commonly used pyrotechnic detonator is competent in most blasts unless structures need to be protected from their resonances.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Interstitial lung disease (ILD) is the most widespread and fatal pulmonary complication of rheumatoid arthritis (RA). Existing knowledge on the prevalence and risk factors of rheumatoid ...arthritis-associated interstitial lung disease (RA-ILD) is inconclusive. Therefore, we designed this review to address this gap.
To find relevant observational studies discussing the prevalence and/or risk factors of RA-ILD, EMBASE, Web of Science, PubMed, and the Cochrane Library were explored. The pooled odds ratios (ORs) / hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated with a fixed/ random effects model. While subgroup analysis, meta-regression analysis and sensitivity analysis were carried out to determine the sources of heterogeneity, the
statistic was utilized to assess between-studies heterogeneity. Funnel plots and Egger's test were employed to assess publication bias. Following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, our review was conducted.
A total of 56 studies with 11,851 RA-ILD patients were included in this meta-analysis. The pooled prevalence of RA-ILD was 18.7% (95% CI 15.8-21.6) with significant heterogeneity (
= 96.4%). The prevalence of RA-ILD was found to be more likely as a result of several identified factors, including male sex (ORs = 1.92 95% CI 1.70-2.16), older age (WMDs = 6.89, 95% CI 3.10-10.67), having a smoking history (ORs =1.91, 95% CI 1.48-2.47), pulmonary comorbidities predicted (HRs = 2.08, 95% CI 1.89-2.30), longer RA duration (ORs = 1.03, 95% CI 1.01-1.05), older age of RA onset (WMDs =4.46, 95% CI 0.63-8.29), positive RF (HRs = 1.15, 95%CI 0.75-1.77; ORs = 2.11, 95%CI 1.65-2.68), positive ACPA (ORs = 2.11, 95%CI 1.65-2.68), higher ESR (ORs = 1.008, 95%CI 1.002-1.014), moderate and high DAS28 (≥3.2) (ORs = 1.87, 95%CI 1.36-2.58), rheumatoid nodules (ORs = 1.87, 95% CI 1.18-2.98), LEF use (ORs = 1.42, 95%CI 1.08-1.87) and steroid use (HRs= 1.70, 1.13-2.55). The use of biological agents was a protective factor (HRs = 0.77, 95% CI 0.69-0.87).
The pooled prevalence of RA-ILD in our study was approximately 18.7%. Furthermore, we identified 13 risk factors for RA-ILD, including male sex, older age, having a smoking history, pulmonary comorbidities, older age of RA onset, longer RA duration, positive RF, positive ACPA, higher ESR, moderate and high DAS28 (≥3.2), rheumatoid nodules, LEF use and steroid use. Additionally, biological agents use was a protective factor.
Abstract
Lenticular galaxies (S0s) were considered mainly as passive evolved spirals due to environmental effects for a long time; however, most S0s in the field cannot fit into this common scenario. ...In this work, we study one special case, Sloan Digital Sky Survey J120237.07+642235.3 (PGC 38025), a star-forming field S0 galaxy with an off-nuclear blue core. We present optical integral field spectroscopic observation with the 3.5 meter telescope at Calar Alto Observatory, and high-resolution millimeter observation with the NOrthern Extended Millimeter Array. We estimated the star formation rate (SFR = 0.446
M
⊙
yr
−1
) and gaseous metallicity (12 + log(O/H) = 8.42) for PGC 38025, which follows the star formation main sequence and stellar mass–metallicity relation. We found that the ionized gas and cold molecular gas in PGC 38025 show the same spatial distribution and kinematics, while rotating misaligned with stellar component. The off-nuclear blue core is locating at the same redshift as PGC 38025 and its optical spectrum suggest it is H
ii
region. We suggest that the star formation in PGC 38025 is triggered by a gas-rich minor merger, and the off-nuclear blue core might be a local star formation happened during the accretion/merger process.
PDF
