比较不同包装膜对白灵菇的保鲜效果

研究了三种包装膜（PE、PE+微孔、PP）对白灵菇贮藏品质的影响,并探究其影响的机制。结果表明：聚乙烯（Polytene,PE）包装膜白灵菇褐变程度为所有处理最低,外观品质最好。贮藏至第12天,可溶性蛋白和还原糖的含量分别提高了21.39%、70.68%,总糖含量为所有处理中最高。重量和硬度分别下降了0.82%、1.15%,电导率和丙二醛（Malondialdehyde,MDA）含量最低,几丁质酶（Chitinase,CHT）和β-1,3-葡聚糖酶（β-1,3-glucanase,Glu）活性分别降低了46.87%、48.56%。超氧化物歧化酶（Superoxide Dismutasee,SOD）和过氧化氢酶（Catalase,CAT）的活性最高,其中CAT的活性提高了2.42倍。抗氧化物质类黄酮和总酚含量分别提高了1.62倍、8.18倍。木质素含量增加了1.20倍。PE+微孔处理贮藏后期虽增强SOD活性及提高抗氧化物质的生成,但延缓褐变效果较差。聚丙烯（Polypropylene,PP）处理组褐变氧化、失重则最严重。综上,PE包装膜的贮藏效果最佳,其可能通过延缓细胞壁的降解,提高抗氧化酶活性和抗氧化物质含量来增强其抗氧化性,该研究结果可为白灵菇采后贮藏保鲜技术提供一定的参考依据。     

不同预处理和干燥方式下养心菜粉色泽、功能成分和抗氧化性水平 的比较

为了研究养心菜的加工适用性,拓展其利用途径,采用未预处理（Untreated,UT）、沸水漂烫（Boiling Water Blanching,BWB）、沸水+护色漂烫（COLOR Protection+Water Blanching,CPB）、蒸汽漂烫（Steam Blanching,SB）与冻融（Freeze-Thawing,FT）五种预处理方式处理后,分别进行热风干燥（Hot Air Drying,HA）、热泵干燥（Heat Pump Drying,HP）,得到UT HP、UT HA、BWB HP、BWB HA、CPB HP、CPB HA、SB HP、SB HA、FT HP及FT HA 10种养心菜粉,比较不同预处理方式和干燥方式下养心菜色泽、功能成分及抗氧化能力水平的变化。结果表明：UT HP没食子酸和山萘酚含量最高,但色泽差、叶绿素含量较低,干燥时间长;CPB HP的干燥时间短,Vc含量最高,具有较高的抗氧化水平,但没食子酸含量较低;SB HP总酚、总黄酮、槲皮素含量最高,其他品质指标介于中间;FT HP养心菜具有最好的色泽、最高的叶绿素、游离氨基酸含量,但总酚、总黄酮、槲皮素、山萘酚以及抗氧化水平低。从主成分分析来看,BWB HP、CPB HP、SB HP 和BWB HA、CPB HA、SB HA的养心菜品质分别具有一定的相似性,UT HP、FT HP、UT HA、UT HA和其有明显差异。该文综合比较了养心菜不同预处理及干燥方法的优劣,在养心菜下游的功能性食品的开发过程中,可以根据需求选择合适的干燥方法。     

Some observations on the role of oxygen in lubricated wear

The role of oxygen in lubricated wear is discussed. Previous studies have shown that at low concentrations, oxygen can reduce wear, but at higher concentrations, it can increase wear. The situation is complicated by ZDTP antioxidants. The present paper reports experimental work aimed at elucidating the role of hydroperoxides - whether they participate in the formation of wear-resistant oxide films, if they (or peroxy radicals) are the main source of oxygen, and whether ZDTP-hydroperoxide interactions in the wear zone are important in controlling wear.     

The Effect of Fullerenol C60(OH)36 on the Antioxidant Defense System in Erythrocytes

Background: Fullerenols (water-soluble derivatives of fullerenes), such as C₆₀(OH)₃₆, are biocompatible molecules with a high ability to scavenge reactive oxygen species (ROS), but the mechanism of their antioxidant action and cooperation with endogenous redox machinery remains unrecognized. Fullerenols rapidly distribute through blood cells; therefore, we investigated the effect of C₆₀(OH)₃₆ on the antioxidant defense system in erythrocytes during their prolonged incubation. Methods: Human erythrocytes were treated with fullerenol at concentrations of 50–150 µg/mL, incubated for 3 and 48 h at 37 °C, and then hemolyzed. The level of oxidative stress was determined by examining the level of thiol groups, the activity of antioxidant enzymes (catalase, glutathione peroxidase, glutathione reductase, and glutathione transferase), and by measuring erythrocyte microviscosity. Results: The level of thiol groups in stored erythrocytes decreased; however, in the presence of higher concentrations of C₆₀(OH)₃₆ (100 and 150 µg/mL), the level of -SH groups increased compared to the control. Extending the incubation to 48 h caused a decrease in antioxidant enzyme activity, but the addition of fullerenol, especially at higher concentrations (100–150 µg/mL), increased its activity. We observed that C₆₀(OH)₃₆ had no effect on the microviscosity of the interior of the erythrocytes. Conclusions: In conclusion, our results indicated that water-soluble C₆₀(OH)₃₆ has antioxidant potential and efficiently supports the enzymatic antioxidant system within the cell. These effects are probably related to the direct interaction of C₆₀(OH)₃₆ with the enzyme that causes its structural changes.     

Development and testing of a screw compressor fluid based on two-stage hydrotreated base oils,and comparison with a synthetic fluid

This paper reports the development and testing of a rotary screw compressor lubricant based on two-stage severely hydrotreated petroleum base oil, and compares the fluid's performance with that of a synthetic polyalphaolefinbased compressor fluid. It was found that performance was in most respects the same for both fluids. Laboratory and performance testing also shows equivalent extended service life greater than one year, with reduced maintenance and energy savings.     

An investigation into the antiwear,antioxidation, and anticorrosion behaviour of some derivatives of 2,5-dimercapto -1,3,4-thiadiaxole

It appears that the comprehensive performance of 2,5-dimercapto-1,3,4-thiadiazole derivatives is dependent upon both the type and the structure of the chains attached to the carbon atoms in the 2 and 5 positions of the thiadiazole ring. For the side chain of the monosulphide type R-S-, the type and location of substituents have an important influence on additive performance. In the case of the side chain of the disulphide type, X-SS-, the presence of the phosphorus-containing group has a significant effect on multifunctionality.     

Improvement of antioxidation and antiwear properties of polyalphaolefin oils

Polyalphaolefin-based lubricating oils were tested on a four-ball tester, and in a stability test, with antiwear and antioxidant additives of different types, along with other (petroleum and alkylbenzene) base oils and additives. Antioxidant additives for PAOs essentially influence their thermo-oxidation stability. It was found that binary inhibitors increased thermo-oxidation stability effectively. In the antiwear tests, the addition of additives to PAOs sharply decreased wear scar diameters. A significant difference was observed in the action of small concentrations of antiwear additives as between PAO, alkylbenzene and mineral oils. Explanations of this behaviour are put forward.     

Identification of In Vitro Metabolites of Synthetic Phenolic Antioxidants BHT,BHA, and TBHQ by LC-HRMS/MS

Butylated hydroxytoluene (BHT) and its analogs, butylated hydroxyanisole (BHA) and tert-butyl-hydroquinone (TBHQ), are widely used synthetic preservatives to inhibit lipid oxidation in the food, cosmetic and pharmaceutical industries. Despite their widespread use, little is known about their human exposure and related biotransformation products. The metabolism of these compounds was investigated using in vitro incubations with human and rat liver fractions. Liquid chromatography coupled to high-resolution tandem mass spectrometry was employed to detect and characterize stable and reactive species formed via oxidative metabolism, as well as phase II conjugates. Several oxidative metabolites have been detected, as well as glutathione, glucuronide, and sulfate conjugates, many of which were not previously reported. A combination of accurate mass measurements, MS/MS fragmentation behavior, and isotope-labeling studies were used to elucidate metabolite structures.     

葛根总黄酮的提取及抗氧化特性研究

分别考察醇提法和水提法对葛根总黄酮提取率的影响,结合对鲜豆油抗氧化性能试验,醇提法提取率是水提法提取率的2倍左右,醇提物比空白样的油脂氧化诱导期延长60%左右,比水提物的氧化诱导期延长8.3%左右,结果醇提法优于水提法。利用正交试验对醇提法的提取条件进行优化,在乙醇浓度30%、料液比1∶10,80℃下回流提取90min时,葛根总黄酮提取率达4.756%。对醇提物进行定性检识和和定性检测。对葛根总黄酮进行抑制邻苯三酚自氧化试验研究。在2.5g/L时对邻苯三酚自氧化抑制率为13.98%。葛根总黄酮抗氧化作用明显,可作为抗氧化剂应用到食品工业中。