Recrystallization in Model Ice Cream Solutions as Affected by Stabilizer Concentration

Ice recrystallization rates in simple aqueous solutions comprising fructose and a hydrocolloid stabilizer were measured. The stabilizers were an enzyme-modified guar and a non-gelling high methoxy pectin. The stabilizer concentration dependence of the recrystallization rates for both materials was similar in that increasing the concentration resulted in decreasing rates until a point is reached where further addition had no additional effect. That recrystallization rates were reduced by both gelling and non-gelling stabilizers was strongly suggestive that gelation was not a requirement for recrystallization inhibition and another more specific mechanism applies, for example a weak interfacial effect such as adsorption or blocking. This behavior was also seen with locust bean gum and guar and provided further empirical evidence to support the hypothesis that stabilizers adsorb to ice crystal surfaces.     

甲苯—正庚烷—庚烯-(3)三元系统的气液平衡

测定了庚烯-（3）的蒸气压。用Gillespie型平衡器测定了甲苯—庚烯-（3）、正庚烷—庚烯-（3）二元系及甲苯—正庚烷—庚烯-（3）三元系统的平衡数据,并分别用Spinner及White方法验证了这些数据,计算结果与实验结果是符合的。三元系统气液平衡的数据不论在工程中或是实验工作上都很重要,过去对三元系统气液平衡的研究虽然有一些,但对甲苯—正庚烷—庚烯-（3）三元系统气液平衡至今在文献上尚未有记载。 由于庚烯-（3）的蒸气压数据不见于文献,我们测定了它的蒸气压数据。正庚烷—甲苯二元系统前人已有许多结果发表,我们进行了一些校核,结果与文献记载符合。甲苯—庚烯-（3）二元系统文献上没有,我们倣效了并用Spinner方法及White方法整理。至于正庚烷—庚烯-（3）二元系统,因为此两组分的性质（如沸点、n_D~（20）等）极其接近,分析误差较大,我们将其当作理想溶液处理,误差当在允许误差以内。 三元系统的分析较为繁难,误差也较大,故希望从理论和实验材料找出其规律性,以校核实验数据和推算未知三元系统。本工作利用三个二元系统的数据,用Spinner以及White的方法推算三元系统的气液平衡,与实验数据相比较,是相互符合的。     

Optimum control of deterministic and stochastic distributed populations with intra-species competition†

Most of the literature devoted to the study of dynamic populations with predators is focused on the use of the so-called ‘population law’ discovered by Verhulst in 1937, and generalized later by several authors. Basically this model deals with the total number of individuals in the population, irrespective of their distribution over the geographical space of definition. In contrast, the present paper suggests a distributed approach to populations with intra-species competitions, which explicitly takes into account the distributed parameter, for instance the age, of the individuals. Two models are given: a distributed version of the logistic law and a generalization of the transfer equation, and two frameworks are considered: the deterministic case and the stochastic one. The equations so obtained are mainly distributed differential integral equations; one considers The optimum control or such systems and necessary optimality conditions are given. The covariance of the deviation from a steady state in the presence of random fluctuations is derived. This model applies not only to biological populations, but also to social and economic systems, and it may be used as a basis for general studies on populations with intra-species competitions.     

Nouvelle méthode pour améliorer la précision du premier harmonique†

In this paper, we give first a contribution to the ‘dual input describing function’ of West et al. (1956); we show how it is possible to define by means of the characteristic curve of the non-linearity alone, without knowing the mathematical expression for it. Secondly, we give a new method for determining the self-oscillation of a non-linear system dependent on reactive energy considerations. Lastly, we extend the theory to non-linear multivariable systems.

On donne une contribution à la notion de ‘double fonetion de transfert équivalente’ de West et al. (1956), et on montre comment il est possible déterminer uniquement à l'aide de la courbe de gain g(x), sans connaicirc;tre son expression mathématique. On donne une nouvelle méthode pour améliorer la précision du premier harmonique, basée sur des considérations relatives à l'énergie réactive du systéme.     

DESIGNING 2 POLE AND 2/4 POLE WINDINGS BY THE SIMULATED ANNEALING METHOD

ABSTRACT

The object of the present paper is to explore the possibility of using simulated annealing procedures to determine multi-speed three phase windings. It is limited to the very simple case of p/2p polarities. The program has yielded the very well known solutions; thus, research may proceed towards more difficult problems.     

Valeur d'un test in vitro d'incorporation de glucose marque pour l'estimation de l'activité antiseborrheique

Deux methodes d'estimation de l'activité antiséborrhéique, l'une in vitro , l'autre in vivo , ont été comparées en étudiant l'action de deux produits différents: le metbufen et la N-sébaçoylméthionine. Le test in vitro d'incorporation de glucose marqué est pratiqué sur la glande préputiale de rat isolée. In vivo , sur la peau de rat castré et supplémenté par l'énanthate de testortérone, l'effet de traitement topique est suivi par l'étude histologique des glandes sébacées.
Les résultats obtenus avec les deux produits essayés présentent un parallélisme permettant de conclure à la validité du test in vitro dans le screening de molécules à activité antiséborrhéique.
An in vitro test for the evaluation of antiseborrheic activity     

Hydration behaviour of synthetic saponite at variable relative humidity

Hydration behaviour of synthetic saponite was examined by X-ray powder diffraction simulation at various relative humidities (RH). The basal spacing of the Ca-saponite increased stepwise with increase in RH. The (00l) reflections observed reflect single or dual hydration states of smectite. Quasi-rational, intermediate, or asymmetrical reflections were observed for all XRD patterns and reflecting heterogeneity of the samples, especially along the transition between two hydration states.     

Visualization and quantification of vesicle trafficking on a three-dimensional cytoskeleton network in living cells

Recent progress in biology and microscopy has made it possible to acquire multidimensional data on rapid cellular activities. Unfortunately, the data analysis needed to describe the observed biological process still remains a major bottleneck. We here present a novel method of studying membrane trafficking by monitoring vesicular structures moving along a three-dimensional cytoskeleton network. It allows the dynamics of such structures to be qualitatively and quantitatively investigated. Our tracking method uses kymogram analysis to extract the consistent part of the temporal information and to allow the meaningful representation of vesicle dynamics. A fully automatic extension of this method, together with a statistical tool for dynamic comparisons, allows the precise analysis and comparison of overall speed distributions and directions. It can handle typical complex situations, such as a dense set of vesicles moving at various velocities, fusing and dissociating with each other or with other cell compartments. The overall approach has been characterized and validated on synthetic data. We chose the Rab6A protein, a GTPase involved in the regulation of intracellular membrane trafficking, as a molecular model. The application of our method to GFP-Rab6A stable cells acquired using fast four-dimensional deconvolution video-microscopy gives considerable cellular dynamic information unreachable using other techniques.     

ALPHA-TOCOPHEROL EFFECTS ON COLOR AND SENSORY CHARACTERISTICS OF GROUND PORK DURING RETAIL DISPLAY

To assess the effects of a-tocopherol addition on lipid and pigment oxidation of ground pork, 10, 100 or 1000 ppm was added directly to ground pork in a food grade carrier (2% Medium Chain Triglyceride Oil) then pork was overwrapped with polyvinyl-chloride film and displayed at 4C for three days. Addition of α-tocopherol to ground pork had limited effects on color and sensory characteristics. Display time and light present during display had detrimental effects on a* value, total color, red color contributed by oxymyoglobin, percent of myoglobin, metmyoglobin and oxymyoglobin, visual red and grey colors.