EFFECTIVENESS OF RINSES IN ALLEVIATING BITTERNESS AND ASTRINGENCY RESIDUALS IN MODEL SOLUTIONS1,2

A two‐part study determined the effectiveness of gum‐based rinses with or without oil for alleviating residuals of a bitter (0.8 g/L caffeine solution) and an astringent (1g/L alum solution) stimuli in serial responses using a sip and spit method. In Experiment 1, rinsing with deionized water was compared to rinsing with 0.3% xanthan gum in water alone or with 5% corn oil and 0.55% carboxymethyl cellulose (CMC) in water alone or with 5% or 10% corn oil. The 0.3% xanthan gum and 5% corn oil mixture resulted in the highest stimulus intensity difference before and after rinsing, whereas 0.55% CMC had a value of nearly zero for residual effect. Results of a two‐alternative forced choice test used in Experiment 2 indicated that both were equally effective for reducing bitterness residuals, but 0.55% CMC solution resulted in the lowest (p=0.007) residual effect for astringency. Therefore, the 0.55% CMC rinse was considered an effective interstimulus rinse to use for assessing both bitterness and astringency in model solutions.     

EVALUATION OF BITTERNESS OF CAFFEINE IN HOT CHOCOLATE DRINK BY CATEGORY, GRAPHIC, AND RATIO SCALING

Perceived intensity of bitterness of caffeine (0.5 - 1.6 g/100 mL) and of quinine HCI (0.5 - 1.6 g/L) added to hot cocoa gave similar response distributions with concentration by category scales (CS) and magnitude estimation (ME). Using caffeine additives, CS and graphic analogue scales (GS) gave similar bitterness response functions. Parabolic functions provided the best fit between concentration and ratings for CS, GS and ME. The data demonstrated no difference for ME of bitterness intensity between free or fixed moduli. Hedonic responses also were not modified by whether the modulus was free or fixed, however, greater ME values were ascribed to lower concentrations in the series when the reference was 4 g/L than when it was 2 g/L caffeine. CS intensity response distributions were similar between a series with a larger number of low levels versus a series with a larger number of high levels across the same concentration range. The results indicate that ME may be inappropriate for scaling of degree of liking, independent of type of modulus.     

TASTE GROUP THRESHOLDS AND SENSORY EVALUATION OF SPANISH WINE VINEGARS

Wine vinegar is a product obtained from wine acidification which contains at least 5% by wt. of acetic acid, in general without any additives or colorings.
Aspects studied in this work include: the determination of the taste group thresholds (geometric mean of the individual best-estimate thresholds "BET") of two different acids (citric and acetic acids) in aqueous solution and spanish vinegars produced from table and sherry wines. The results obtained suggest that wine vinegar can be considered something more than just an acidulant agent.
In order to evaluate differences among wine vinegars, discriminant tests for twenty-five spanish vinegars (sherry, table and flavored vinegars) were applied. Six of the twelve attributes freely chosen by assessors allowed grouping of the spanish wine vinegars according to their sensory aspects.     

OSCILLATIONS AND GLOBAL ATTRACTIVITY OF PERIODIC SOLUTION IN A MODEL OF RESPIRATORY DYNAMICS

61．IntroductionIn〔2〕and〔5〕，MackeyandGlasshaveproposedamodelforresplratorydynamlcswhichIsbasedonthelevelofconcentrationofCOzInthe．arterialbloodofamammal．Let一（t）b6th68ft6fls！COflC6lltfstlottofCOZ，th6flH［sgOV6tfl6dbyth66qU8tlofiwherer，p，0，narepositiveparameters，rlsanonnegatlvedelayandvmdenotesthemaxi－—uffi‘V6tttllst1Ofl’rateOfCOZ．Iflsf6Celltpsp6f〔3），GOpslS8ffiy6tslObtslllEdSUfflCIElltconditionsforallpositivesolutionsof（1．1）tooscillateaboutthePositiveequl…     

大鼠实验性血栓模型的建立及其评价

根据Ｖｉｒｃｈｏｗ血栓形成原理,采用机械性损伤内膜,同时降低血流速度方法制备大鼠实验性血栓模型。结果显示,利用此方法制备血栓模型成功率为７８．４％,血栓平均长度８．５３±１．４２ｍｍ,血栓形成后,腹主动脉的收缩功能明显下降。     

STUDY ON SENSORY AND COMPOSITION CHANGES IN ITALIAN AMARONE VALPOLICELLA RED WINE DURING AGING

Amarone is a red wine produced with a technique already known to the ancient Romans, based on withered grapes and a slow fermentation. Amarone is now considered to be one of the great Italian wines and it is exported all over the world. Sensory and compositional analyses were carried out to describe the profile of the Amarone over four vintages (1998–2001) at different stages of aging. All wines were analyzed for titratable and volatile acidity, pH, alcohol content, residual sugars, t‐resveratrol, antioxidant power, color, tonality, total polyphenols and anthocyans. Twelve trained people evaluated aroma and flavor attributes of all the wines in triplicate in a sensory session. Principal component analysis (PCA) of chemical, physical and sensory data for Amarone wine allowed us to highlight the differences between the wines. In general, the 1998 and 1999 vintages had higher aroma and flavor of Wood and Alcohol than the 2000 vintage, which, on the other hand, had higher aroma and flavor of Liquor and Cherry in alcohol. In contrast, the younger wine (2001 vintage) was the more Astringent and had many polyphenols and anthocyans, distinctive features for a red wine that has been in the cask for a short time.     

ALTERATION OF THE CONFORMATION OF PROTEINS IN RED BLOOD CELL MEMBRANES AND IN SOLUTION BY FIXATIVES USED IN ELECTRON MICROSCOPY

The effects of several commonly employed fixatives on the three-dimensional conformations of two soluble proteins and the protein of intact red blood cell membranes have been studied by means of circular dichroism measurements in the spectral region of the peptide absorption bands. The fixatives used produced significant and parallel conformational changes in all of the proteins, in the increasing order: glutaraldehyde; OsO₄; glutaraldehyde followed by OsO₄; and KMnO₄. The last two treatments obliterated most of the helical character of the proteins. The significance of these observations to the preparation of specimens for electron microscopy is discussed.     

二维不定常嗅觉模型及其精确解

在考虑了鼻腔结构的基础上,把嗅觉反应的主要机理分成四个连续的主要过程,建立了二维不定常的嗅觉模型,利用分离变量法得到了该模型的精确解,并给出了两个无量纲参数影响气味分子在粘膜层内分布的计算结果,精确解则揭示了各生理参数之间的内在联系。理论和数值结果表明：吸气速度和嗅粘膜表面的粘液是影响嗅觉反应的两个重要因素。这些结果对进一步研究嗅觉反应机理具有一定的参考价值     

YHPD及其分离组份在溶液中和CHO细胞内的吸收和荧光特征

本文报道了YHPD及其用HPLC方法分离得到的四种主要组份在溶液中和CHO细胞内的吸收和荧光特性.YHPD分离组份d在稀溶液状态(0.5μg/ml)与其它三种组份不同,表现出较稳定的聚集态性质,YHPD及组份摄入细胞后,荧光光谱和Soret吸收峰明显红移,荧光量子产额增高.同时看到YHPD的吸收和荧光特性受环境中H~ 浓度的影响     

SYNTHESIS AND IN VITRO EVALUATION OF NOVEL ANTI-VARICELLA-ZOSTER VIRUS (VZV) NUCLEOSIDES

A series of alkyl-aryl, -phenoxy, and -thiophenoxy bicyclic furo pyrimidine nucleosides have been successfully synthesised by Pd-coupling of 5-iodo-2′-deoxyuridine (IDU) with terminal alkynes, followed by in situ copper-cyclisation. Synthesised compounds (4a-i) showed an anti-VZV activity at low μM concentration, comparable to that of current treatment acyclovir.     

EFFECTS OF SAMPLING CONDITIONS ON TEMPORAL PERCEPTION OF BITTERNESS IN YERBA MATE (ILEX PARAGUARIENSIS) INFUSIONS

Time-intensity (TI) methodology and a trained panel were used to characterize the perceived bitterness of Yerba mate (YM) Ilex paraguariensis infusions. Two sampling procedures (sip and spit; sip and swallow) and two conditions for residence time in mouth (free or fixed duration of 5 s until spit or swallow) were evaluated.
At a fixed duration the maximum bitterness as well as the time to reach it showed a significant YM concentration dependence. No change on bitterness was observed by swallowing or spitting YM infusions except a larger rate of decay of the response (v_r) at spit condition. Dynamic bitterness at free sampling time showed that the decision period to spit or swallow the YM infusion approximately duplicated the fixed one of 5 s.     

邛崃和相岭山系小熊猫种群的遗传结构

测定了来自小熊猫主要分布的两大山系———相岭和邛崃的 2 3只小熊猫样品的mtDNA控制区 5’端 5 69bp序列 ,共发现 2 3个变异位点 ,定义了 8种单元型 ,其中邛崃山系 5种 ,相岭山系 3种。分析结果表明 ,两山系均表现出较低的核苷酸多态性 ;单元型多态性差异明显 ,其中邛崃山系高于相岭山系。分子变异分析表明 ,两山系的小熊猫种群间具有较高的基因流 (Nm =2 95 ) ,两种群遗传分化不明显 (ΦST=0 1 45 ,P >0 0 5 )。结合细胞色素b序列分析 ,认为两种群可能是从经历了近期瓶颈效应的同一祖先群衍生而来 ,并且可将两山系的小熊猫种群作为一个管理单元进行保护和管理     

国产和进口DMEM培养基培养CHO—C28工程细胞的质量评价

我们用10L转瓶培养能高效表达HBsAg的重组中国仓鼠卵巢细胞(CHO-C_(28)细胞株),在相同的培养条件下比较国产和进口DMEM培养基的质量。结果表明,两种DMEM培养的细胞之生长及分泌的HBsAg之滴度没有显著改变,国产DMEM培养的细胞收液的沉淀收率略高于进口DMEM的,前者的最后收率也不低于后者。两种DMEM培养的细胞收液经纯化后,HBsAg的各项指标都符合基因工程乙肝疫苗制造及检定规程的标准,从试验结果可以看出,用国产DMEM培养基替代进口DMEM培养基是完全有可能的。