Effects of cola drinks on the morphology and elastic modulus of dentin

The mechanical and morphological degradation that human dentin undergoes after prolonged exposure in cola drinks was examined using nanoindentation and AFM. The elastic modulus of the dentin prior cola exposure was 18.28 ± 1.7 GPa, while after exposure it had decreased to 4.25 ± 1.4 GPa on the surface that was in direct contact with the drink, and to 13.38 ± 2.9 GPa on the surface that was in indirect contact with the drink. AFM documented the corrosion effects of the cola through topography images and histograms of the RMS roughness.     

紫外分光光度法测可乐中咖啡因的含量

目的:用紫外分光光度法测定可乐中咖啡因的含量,建立测定可乐中咖啡因的含量的紫外分光光度法的最佳工作条件。方法:采用离心的方法提取样品中的咖啡因,用紫外分光光度法在276 nm处测含量。结果:咖啡因浓度在5～50μg/mL范围内与紫外吸收有较好的线性关系(y=0.0489x-0.0084,R2=0.9991)。可口可乐中咖啡因的含量为93.5μg/mL,回收率为99.1%,RSD%为0.94%;百事可乐中咖啡因的含量为101.0μg/mL,回收率为100.4%,RSD%为0.64%。结论:此方法准确、简单、快速,适合可乐中咖啡因的含量测定。     

Sweetness intensity perception and pleasantness ratings of sucrose, aspartame solutions and cola among multi-ethnic Malaysian subjects

As the sugar intake of Malaysians is one of the highest in the Asia Pacific region, we wanted to investigate how this high prevalence of ‘sweet tooth’ is influenced by biological determinants like age, gender, ethnicity and Body Mass Index (BMI). This study therefore sought to use the generalized Labeled Magnitude Scale to evaluate the sweetness intensity perception and pleasantness ratings of not only three increasing suprathreshold concentrations of sucrose and a popular naturally-sweetened carbonated beverage - Coca-Cola®, but also their non-nutritive sweetener (NNS) counterparts - aspartame and Coca-Cola Light®. Taken together, the overall intensity of NNS solutions and beverage was perceived as significantly higher, but not for their pleasantness. The intensity perception and pleasantness of most sweet solutions were not significantly associated with gender and BMI. Overall, Malays had a lower perceived intensity of sweet stimuli compared to other ethnicities, but a conclusion of the influence of ethnicity on sweetness pleasantness could not be met. Lastly, sweetness intensity perception and pleasantness ratings for both colas decreased significantly with age.     

基于Pro/E和MasterCAM软件的可乐瓶底模型数控加工

运用CAD/CAM技术对可乐瓶底凹模型腔进行数控加工的实例,介绍Pro/E和MasterCAM两个软件在加工过程中的具体步骤。首先用Pro/E软件强大的参数化设计功能,快捷的生成可乐瓶底凹模型腔,再利用MasterCAM软件易学易用的加工功能,生成自动刀具轨迹并进行仿真加工,检验零件加工质量,从而生成最优化的数控加工程序,获得最佳实际生产质量。说明配合使用两个软件各自功能上的优点,可以有效提高模具设计及其数控加工的质量和效率。     

可乐饮料中咖啡因的GC／MS定量测定

用GC／MS的内标定量法测定了市场上出售的3种可乐饮料中咖啡因的含量，结果为每毫升饮料中含咖啡因分别为21．18、2．98、1．2μg。     

Cola soft drinks for evaluating the bioaccessibility of uranium in contaminated mine soils

There is a rising need for scientifically sound and quantitative as well as simple, rapid, cheap and readily available soil testing procedures. The purpose of this study was to explore selected soft drinks (Coca-Cola Classic®, Diet Coke®, Coke Zero®) as indicators of bioaccessible uranium and other trace elements (As, Ce, Cu, La, Mn, Ni, Pb, Th, Y, Zn) in contaminated soils of the Mary Kathleen uranium mine site, Australia. Data of single extraction tests using Coca-Cola Classic®, Diet Coke® and Coke Zero® demonstrate that extractable arsenic, copper, lanthanum, manganese, nickel, yttrium and zinc concentrations correlate significantly with DTPA- and CaCl₂-extractable metals. Moreover, the correlation between DTPA-extractable uranium and that extracted using Coca-Cola Classic® is close to unity (+ 0.98), with reduced correlations for Diet Coke® (+ 0.66) and Coke Zero® (+ 0.55). Also, Coca-Cola Classic® extracts uranium concentrations near identical to DTPA, whereas distinctly higher uranium fractions were extracted using Diet Coke® and Coke Zero®. Results of this study demonstrate that the use of Coca-Cola Classic® in single extraction tests provided an excellent indication of bioaccessible uranium in the analysed soils and of uranium uptake into leaves and stems of the Sodom apple (Calotropis procera). Moreover, the unconventional reagent is superior in terms of availability, costs, preparation and disposal compared to traditional chemicals. Contaminated site assessments and rehabilitation of uranium mine sites require a solid understanding of the chemical speciation of environmentally significant elements for estimating their translocation in soils and plant uptake. Therefore, Cola soft drinks have potential applications in single extraction tests of uranium contaminated soils and may be used for environmental impact assessments of uranium mine sites, nuclear fuel processing plants and waste storage and disposal facilities.     

Assay of advanced glycation endproducts in selected beverages and food by liquid chromatography with tandem mass spectrometric detection

Food and beverages contain protein glycation adducts--both early-stage adducts and advanced glycation endproducts. We determined the concentrations of glycation adducts in selected food and beverages by liquid chromatography with triple quadrupole mass spectrometric detection. Cola drink contained low concentrations of glycation free adducts, whereas pasteurised and sterilised milk were rich sources of heat-stable glycation adduct residues--Nepsilon-carboxymethyl-lysine and Nepsilon-carboxyethyl-lysine. Laboratory rodent food was a rich source of advanced glycation endproducts. Measurement of glycation adducts in 24 h urine samples of normal and diabetic rats indicated that < 10% of glycation adduct residue consumption was excreted. Induction of diabetes by streptozotocin led to a 2-fold increase in urinary excretion of Nepsilon-carboxymethyl-lysine and a 27-fold increase in urinary excretion of methylglyoxal-derived hydroimidazolone Ndelta-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine - the latter was decreased by high-dose thiamine therapy that also prevented the development of nephropathy. We conclude that cola drinks are a poor source of glycation adduct whereas thermally processed milk is rich in glycation adducts. Dietary glycation adducts residues probably have low bioavailability. Experimental diabetes is associated with a marked increase in exposure to endogenous formation of methylglyoxal-derived hydroimidazolone which is linked to the development of diabetic nephropathy.