A Protein Aggregation Based Test for Screening of the Agents Affecting Thermostability of Proteins

To search for agents affecting thermal stability of proteins, a test based on the registration of protein aggregation in the regime of heating with a constant rate was used. The initial parts of the dependences of the light scattering intensity (I) on temperature (T) were analyzed using the following empiric equation: I = Kagg(T−T0)2, where Kagg is the parameter characterizing the initial rate of aggregation and T0 is a temperature at which the initial increase in the light scattering intensity is registered. The aggregation data are interpreted in the frame of the model assuming the formation of the start aggregates at the initial stages of the aggregation process. Parameter T0 corresponds to the moment of the origination of the start aggregates. The applicability of the proposed approach was demonstrated on the examples of thermal aggregation of glycogen phosphorylase b from rabbit skeletal muscles and bovine liver glutamate dehydrogenase studied in the presence of agents of different chemical nature. The elaborated approach to the study of protein aggregation may be used for rapid identification of small molecules that interact with protein targets

Influence de la gélification de ploysaccharide sur les systèmes mixtes (agrégats de protéine globulaire \ polysaccharide)

Le mélange à température ambiante à pH7 dans 0.1M NaCl d'agrégats de b-lactoglobuline avec un polysaccharide, le -carraghénane ( -car) conduit, si la concentration en -car est suffisante, à une séparation de phases avec la formation de micro-domaines sphériques de quelques microns riches en protéine qui précipitent avec le temps et qui contiennent les agrégats plus ou moins interpénétrés. Cette incompatibilité est fortement dépendante de la concentration en -car, de la taille des agrégats mais faiblement de la concentration en agrégats. La gélification du -car provoque une chute brutale de la turbidité des mélanges dès que la température passe en dessous la température critique de gélification du -car. Cette chute est liée à un changement de structure locale des domaines qui deviennent moins denses, les petits agrégats étant relargués à l'extérieur. Ce phénomène de relargage, lié à la formation du réseau, est rapide, réversible et peut être empêché si le système est vieilli à chaud.Mixtures of b-lactoglobulin (blg) aggregates and a polysaccharide, the -carrageenan ( -car), phase separate at room temperature, pH7 with 0.1M NaCl leading, above a critical -car concentration, to the formation of spherical protein rich microdomains which precipitate slowly and contain the blg aggregates more or less interpenetrated. The phase separation strongly depends on the -car concentration and blg aggregates size but weakly depends on the aggregates concentration. The -car forms a thermoreversible gel below a critical temperature, Tc. Its gelation causes a strong decrease in the turbidity of the mixtures which is due to a changing in the local structure of the domains. The domains become smaller and the smaller aggregates can be released. This fast and reversible release is controlled by the network formation and can be avoid if the mixtures are aged at high temperature (50C) before gelation.LE MANS-BU Sciences (721812109) / SudocSudocFranceF

Tactical planning of a multi-period capacitated two-echelon distribution network with delivery patterns

National audienceA shipper is a company which outsource its transportation to carriers to deliver its customers. Typically, in the retail industry, suppliers can ship several times a week small quantities (a few pallets) to multiple retailer warehouses and superstores. In order to reduce its cost and secure its contracts with its carriers, a shipper typically resorts to integrating a mix of carriers and transportation rates (full-truckload and less-than-truckload), together with consolidation on regional hubs and collaboration with other shippers. This leads to the definition of two-echelon distribution networks. The planning of such distribution networks includes defining efficient load plans for long-haul routes, freight consolidations on regional hubs and distribution routes from hubs to customers [3]. The overall objective is mainly to take decisions related to the booking of resources such as trucks or cross-dock capacities and organize a good collaboration with other shippers. In this context, we focus on several constraints that are seldom integrated in the operations research literature : (i) customers require some regularity : a commodity has to be delivered several times a week [1] on predefined days, (ii) shippers, hubs and customers have capacity constraints that model workload balancing requirements over the days of the week. Accordingly, given a set of suppliers, hubs and customers, given an order history of several weeks, we investigate the problem of assigning a set of delivery weekdays (called delivery patterns [2]) to each customer and for each commodity, in a two-echelon distribution network, such that the sum of transportation costs are minimized and the capacity of each network node is respected

Selecting Delivery Patterns in a Two-Echelon Distribution Problem with Load Balancing

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