107 research outputs found
The effect of friction behavior on the migration of metal elements from stainless-steel articles for food contact
Objective To evaluate the effect of friction behavior on migration levels of metal elements from stainless-steel articles for food contact. Methods The migration levels of metal elements from used and new stainless-steel articles were compared according to GB 4806.9-2016 and Council of Europe Resolution CM/Res (2013) 9. The migration conditions were boiling in 4% acetic acid for 30 min followed by at room temperature for 24 h and soaking in 5 g/L citric acid at 100 ℃ for 2 h, respectively. Meanwhile, the impact of dynamic friction on migration were investigated on new stainless-steel articles, where the friction method were referred to the GB/T 32095.2-2015 standard. Migration of metal elements complied with the corresponding standard. Results Based on the European standard, migration of lead in the first migration test was above limit of quantitation (LOQ) in all five used stainless-steel articles after friction, but none in new ones. The quantification rate of chromium in the first migration test in 80% (4/5) of used stainless-steel articles were above LOQ after friction by GB 4806.9-2016 standard while were 20% (1/5) in new ones. The migration level of Cr was higher by GB 4806.9-2016 standard than by European resolution in single dynamic friction study. Results from the dynamic friction experiments indicated that the migration of Cr and Ni reached equilibrium after 3 times of friction. Conclusion The migration condition in GB 4806.9-2016 standard had stronger leaching ability for Cr from stainless-steel articles than that in European resolution. Friction behavior promoted corrosion and metal element migration of stainless steel. Long-term used stainless-steel products had higher lead and chromium migration than new products, but without safety risks
Effects of acarbose on cardiovascular and diabetes outcomes in patients with coronary heart disease and impaired glucose tolerance (ACE): a randomised, double-blind, placebo-controlled trial.
The effect of the α-glucosidase inhibitor acarbose on cardiovascular outcomes in patients with coronary heart disease and impaired glucose tolerance is unknown. We aimed to assess whether acarbose could reduce the frequency of cardiovascular events in Chinese patients with established coronary heart disease and impaired glucose tolerance, and whether the incidence of type 2 diabetes could be reduced. The Acarbose Cardiovascular Evaluation (ACE) trial was a randomised, double-blind, placebo-controlled, phase 4 trial, with patients recruited from 176 hospital outpatient clinics in China. Chinese patients with coronary heart disease and impaired glucose tolerance were randomly assigned (1:1), in blocks by site, by a centralised computer system to receive oral acarbose (50 mg three times a day) or matched placebo, which was added to standardised cardiovascular secondary prevention therapy. All study staff and patients were masked to treatment group allocation. The primary outcome was a five-point composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, hospital admission for unstable angina, and hospital admission for heart failure, analysed in the intention-to-treat population (all participants randomly assigned to treatment who provided written informed consent). The secondary outcomes were a three-point composite outcome (cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke), death from any cause, cardiovascular death, fatal or non-fatal myocardial infarction, fatal or non-fatal stroke, hospital admission for unstable angina, hospital admission for heart failure, development of diabetes, and development of impaired renal function. The safety population comprised all patients who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov, number NCT00829660, and the International Standard Randomised Controlled Trial Number registry, number ISRCTN91899513. Between March 20, 2009, and Oct 23, 2015, 6522 patients were randomly assigned and included in the intention-to-treat population, 3272 assigned to acarbose and 3250 to placebo. Patients were followed up for a median of 5·0 years (IQR 3·4-6·0) in both groups. The primary five-point composite outcome occurred in 470 (14%; 3·33 per 100 person-years) of 3272 acarbose group participants and in 479 (15%; 3·41 per 100 person-years) of 3250 placebo group participants (hazard ratio 0·98; 95% CI 0·86-1·11, p=0·73). No significant differences were seen between treatment groups for the secondary three-point composite outcome, death from any cause, cardiovascular death, fatal or non-fatal myocardial infarction, fatal or non-fatal stroke, hospital admission for unstable angina, hospital admission for heart failure, or impaired renal function. Diabetes developed less frequently in the acarbose group (436 [13%] of 3272; 3·17 per 100 person-years) compared with the placebo group (513 [16%] of 3250; 3·84 per 100 person-years; rate ratio 0·82, 95% CI 0·71-0·94, p=0·005). Gastrointestinal disorders were the most common adverse event associated with drug discontinuation or dose changes (215 [7%] of 3263 patients in the acarbose group vs 150 [5%] of 3241 in the placebo group [p=0·0007]; safety population). Numbers of non-cardiovascular deaths (71 [2%] of 3272 vs 56 [2%] of 3250, p=0·19) and cancer deaths (ten [<1%] of 3272 vs 12 [<1%] of 3250, p=0·08) did not differ between groups. In Chinese patients with coronary heart disease and impaired glucose tolerance, acarbose did not reduce the risk of major adverse cardiovascular events, but did reduce the incidence of diabetes.</p
Exploring the historical evolution of tourism-environment interaction in protected area: A case study of Mt. Bogda
Hydrophobic modification of cellulose fibres by cationic-modified polyacrylate latex with core-shell structure
Interacting Effects of Nitrogen Addition and Mowing on Plant Diversity and Biomass of a Typical Grassland in Inner Mongolia
It is unclear how N addition and mowing interactively affect grassland community structure and function. We studied the short-term effects of N addition and mowing on the species diversity and biomass of a typical grassland in Inner Mongolia using a split-plot design, with the whole plot representing the mowing treatment and the subplot representing the N addition rate. Three stubble heights were set at 10 cm (M2), 6 cm (M3) and 3 cm (M4), and a no-mowing treatment (M1) was also included. N addition consisted of five rates, i.e., 0 (N1), 2 (N2), 5 (N3), 10 (N4) and 20 (N5) g N m2.yr−1. Mowing significantly increased species diversity. Mowing with a stubble height of 10 cm (M2) significantly increased both species biomass and community biomass. Heavy mowing (3 cm stubble height, M4) weakened the difference in C. squarrosa biomass caused by N addition. Species richness decreased, while community biomass and Leymus chinensis biomass increased significantly with increasing N addition rate. Mowing alleviated the negative effects of N addition on species richness, and this effect was influenced by stubble height. Community biomass and L. chinensis biomass tended to be stable when N addition was greater than 10 g N m2.yr−1. The N saturation threshold of C. squarrosa biomass was much lower than that of community biomass and L. chinensis biomass. Species richness was negatively correlated with the Gini coefficient and litter production, which indicated that light competition and litter accumulation were important factors affecting the decrease in species richness in our study
Characterization of the complete chloroplast genome of Gymnocarpos przewalskii, an endangered species in China and Mongolia
Characteristic Volatile Fingerprints and Odor Activity Values in Different Citrus-Tea by HS-GC-IMS and HS-SPME-GC-MS
Citrus tea is an emerging tea drink produced from tea and the pericarp of citrus, which consumers have increasingly favored due to its potential health effects and unique flavor. This study aimed to simultaneously combine the characteristic volatile fingerprints with the odor activity values (OAVs) of different citrus teas for the first time by headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Results showed that the establishment of a citrus tea flavor fingerprint based on HS-GC-IMS data can provide an effective means for the rapid identification and traceability of different citrus varieties. Moreover, 68 volatile compounds (OAV > 1) were identified by HS-SPME-GC-MS, which reflected the contribution of aroma compounds to the characteristic flavor of samples. Amongst them, the contribution of linalool with sweet flower fragrance was the highest. Odorants such as decanal, β-lonone, β-ionone, β-myrcene and D-limonene also contributed significantly to all samples. According to principal component analysis, the samples from different citrus teas were significantly separated. Visualization analysis based on Pearson correlation coefficients suggested that the correlation between key compounds was clarified. A comprehensive evaluation of the aroma of citrus tea will guide citrus tea flavor quality control and mass production.</jats:p
Influence of the roof lithological characteristics on rock burst: a case study in Tangshan colliery, China
Theoretical investigation of cadmium vapor adsorption on kaolinite surfaces with DFT calculations
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