Novel Methods to Manipulate Autolysis in Sparkling Wine: Effects on Yeast

Sparkling wine made by the traditional method (Méthode Traditionelle) develops a distinct and desirable flavour and aroma profile attributed to proteolytic processes during prolonged ageing on lees. Microwave, ultrasound and addition of β-glucanase enzymes were applied to accelerate the disruption of Saccharomyces cerevisiae, and added to the tirage solution for secondary fermentation in traditional sparkling winemaking. Scanning electron microscopy and flow cytometry analyses were used to observe and describe yeast whole-cell anatomy, and cell integrity and structure via propidium iodide (PI) permeability after 6-, 12- and 18-months post-tirage. Treatments applied produced features on lees that were distinct from that of the untreated control yeast. Whilst control yeast displayed budding cells (growth features) with smooth, cavitated and flat external cell appearances; microwave treated yeast cells exhibited modifications like ‘doughnut’ shapes immediately after treatment (time 0). Similar ‘doughnut’-shaped and ‘pitted/porous’ cell features were observed on progressively older lees from the control. Flow cytometry was used to discriminate yeast populations; features consistent with cell disruption were observed in the microwave, ultrasound and enzyme treatments, as evidenced by up to 4-fold increase in PI signal in the microwave treatment. Forward and side scatter signals reflected changes in size and structure of yeast cells, in all treatments applied. When flow cytometry was interpreted alongside the scanning electron microscopy images, bimodal populations of yeast cells with low and high PI intensities were revealed and distinctive ‘doughnut’-shaped cell features observed in association with the microwave treatment only at tirage, that were not observed until 12 months wine ageing in older lees from the control. This work offers both a rapid approach to visualise alterations to yeast cell surfaces and a better understanding of the mechanisms of yeast lysis. Microwave, ultrasound or β-glucanase enzymes are tools that could potentially initiate the release of yeast cell compounds into wine. Further investigation into the impact of such treatments on the flavour and aroma profiles of the wines through sensory evaluation is warranted.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定胡蜂酒中无机元素

采用电感耦合等离子体原子发射光谱法测定胡蜂酒中20种无机元素,建立无机元素对照指纹图谱,对重金属元素进行风险评估。结果表明,胡蜂酒中无机元素种类丰富,其中P、K、Na元素占测定总元素的96.14%。有害元素Pb、Cd、As、Hg、Cu含量符合国家药典标准要求,Cu的靶标危险系数(THQ)为1.00×10^-2,THQ<1说明摄入的重金属对人体健康造成的影响不明显。不同产区胡蜂酒金属元素含量存在差异,根据金属元素图谱得出元素含量按原子序数顺序出现相似的分布态势。结果表明,胡蜂酒中含有丰富的金属元素,很多为营养微量元素,有害元素(Pb、Cd、As、Hg、Cu)含量符合药典要求,从金属元素方面单一来看,饮用胡蜂酒没有明显的健康风险。胡蜂酒无机元素指纹图谱可为胡蜂酒的鉴别提供一定的的参考依据。     

碳钢的高应力冲击磨损行为研究

在高应力冲击磨损条件下，金属材料的磨损表面很容易形成硬度很高（ＨＶ≥１０００）的白层．采用新的试验方法，研究了碳钢在高应力冲击条件下的磨损特征，并且从分析白层的结构出发，讨论了白层的形成机制和失效模式．结果表明，材料的高应力冲击磨损质量损失与冲击次数之间具有线性关系，韧性较好的低碳钢的耐磨性比高碳钢的好，原因是硬度越高，白层在磨损过程中越容易发生剥层与剥落．白层是一种高度塑性变形层，其内部精细结构的变形特征证实了白层的塑性变形机制     

带加法白噪声的随机Boussinesq方程组的解的渐近行为

考虑速度和温度同时在加法白噪声扰动下的随机Boussinesq方程组的解的渐近特征.可以接轨道得到该随机方程组的唯一解,并可以验证该解生成随机动力系统,进而证明了该随机动力系统存在随机吸引子.     

酒类中微量甲醛的快速测定新方法

在FeCl3存在条件下,甲醛与自制蛋白液显色剂能生成紫色化合物,藉此可以定量测定微量甲醛。方法线性范围为1~10μg/10mL,线性相关系数r2=0.996,检出限为0.05μg/mL。用该法测定经活性炭脱色的啤酒和白酒中的甲醛含量,回收率为96.46%~103.32%,相对标准偏差为1.36%~2.09%(n=6)。     

Birthrates and delay times of Type Ia supernovae

Type Ia supernovae (SNe Ia) play an important role in diverse areas of astrophysics, from the chemical evolution of galaxies to observational cosmology. However, the nature of the progenitors of SNe Ia is still unclear. In this paper, according to a detailed binary population synthesis study, we obtained SN Ia birthrates and delay times from different progenitor models, and compared them with observations. We find that the Galactic SN Ia birthrate from the double-degenerate (DD) model is close to those infe...     

White light electroluminescence from graphene‐enhanced single polymer comprising two color emitters of equal molar ratios

White polymeric light‐emitting diode (WPLED) based on a single polymer, poly(3‐hexylthiophene‐alt‐9,9‐dioctylfluorene) (PTAF), has been successfully demonstrated. This conjugated alternating copolymer, PTAF, comprises 50 mol % of 3‐hexylthiophene which is an orange‐red color chromophore and 50 mol % 9,9‐dioctylfluorene which is a bluish‐green color chromophore. It was synthesized by Suzuki cross‐coupling reaction and has a molecular weight of 15,021 and polydispersity of 1.36. Nanocomposite consisting PTAF and graphene nanosheets enhances the optoelectronic properties and the device fabricated with a configuration of ITO/PEDOT:PSS/(PTAF + 1% graphene)/Ca/Al shows two‐color white electroluminescence with CIE 1931 coordinates of (0.28, 0.34). The white luminescence from a single polymer affords the WPLED device a simple structure and low fabrication cost. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

同轴电喷法制备PCL-蛋清体系复合微胶囊

以鸡蛋的卵清蛋白作为蛋白质药物模板、生物可降解材料聚己内酯(PCL)为药物载体模板,采用同轴电喷法制备PCL-蛋清体系的复合微球.研究了电导率、黏度对于电喷微球成型的影响.核壳溶液推进速率比、电压、溶液质量分数和接收距离等对于所得微球表面形态和结构的影响.利用扫描电子显微镜(SEM)研究了微球的表面形态,用荧光显微镜表征了微球的包覆模式.结果表明:同轴电喷法可以制备PCL-蛋清体系的复合结构微胶囊,其中推进速率比对微球形貌、粒径及其分布的影响比较明显,当PCL与蛋清溶液推进速率比大于10时,将出现具有包覆结构的微球.     

The use of vibrational spectroscopy to study the pathogenesis multiple sclerosis and other neurological conditions

Spectroscopy techniques are valuable tools in biomedical research and have been used extensively in the study of disease. However, neurological conditions such as multiple sclerosis (MS) have received little attention and the available spectroscopy studies are limited, both in overall numbers of patients studied and the disease samples considered. MS is a complex immune-mediated disease, with variable clinical courses and limited therapeutic options. This review aims to summarize current literature in the area, demonstrating how spectroscopy techniques can provide valuable information to inform and advance research into the most common neurological condition affecting young adults.     

Luminescence characteristics of Eu3+ activated borate phosphor for white light emitting diode

In this paper, the Sr₃Y₂ (BO₃)₄:Eu³⁺ phosphor was synthesized by high temperature solid-state reaction method and the luminescence characteristics were investigated. The emission spectrum exhibits one strong red emission at 613nm corresponding to the electric dipole ⁵D₀--⁷F₂ transition of Eu³⁺ under 365nm excitation, this is because Eu³⁺ substituted for Y³⁺ occupied the non-centrosymmetric position in the crystal structure of Sr₃Y₂ (BO₃)₄. The excitation spectrum indicates that the phosphor can be effectively excited by ultraviolet (254nm, 365nm and 400nm) and blue (470nm) light. The effect of Eu³⁺ concentration on the red emission of Sr₃Y₂ (BO₃)₄:Eu³⁺ was measured, the result shows that the emission intensities increase with increasing Eu³⁺ concentration, then decrease. The Commission Internationale del'Eclairage chromaticity (x, y) of Sr₃Y₂(BO₃)₄:Eu³⁺ phosphor is (0.640,0.355) at 15 mol% Eu³⁺.