McNeill's code : Arranged to meet the requirements of mi ning, metallurgical and civil engineers ; directors of mining, smetling and other companies...

UANL

Private Storage of Common Property

This paper examines a characteristic of common property problems unmodeled in the published literature: Extracted common reserves are aften stored privately rather than immediately. We examine the positive and normative effects of such storage.

Développement de papier bioactif par couchage à grande échelle d’enzymes immobilisées par microencapsulation

L’objectif principal de cette recherche est de contribuer au développement de biocapteurs commerciaux utilisant des surfaces de papier comme matrices d’immobilisation, capables de produire un signal colorimétrique perceptible dans les limites sensorielles humaines. Ce type de biocapteur, appelé papier bioactif, pourrait servir par exemple à la détection de substances toxiques ou d’organismes pathogènes. Pour atteindre l’objectif énoncé, ce travail propose l’utilisation de systèmes enzymatiques microencapsulés couchés sur papier. Les enzymes sont des catalyseurs biologiques dotés d’une haute sélectivité, et capables d'accélérer la vitesse de certaines réactions chimiques spécifiques jusqu’à des millions des fois. Les enzymes sont toutefois des substances très sensibles qui perdent facilement leur fonctionnalité, raison pour laquelle il faut les protéger des conditions qui peuvent les endommager. La microencapsulation est une technique qui permet de protéger les enzymes sans les isoler totalement de leur environnement. Elle consiste à emprisonner les enzymes dans une sphère poreuse de taille micrométrique, faite de polymère, qui empêche l’enzyme de s’echapper, mais qui permet la diffusion de substrats à l'intérieur. La microencapsulation utilisée est réalisée à partir d’une émulsion contenant un polymère dissous dans une phase aqueuse avec l’enzyme désirée. Un agent réticulant est ensuite ajouté pour provoquer la formation d'un réseau polymérique à la paroi des gouttelettes d'eau dans l'émulsion. Le polymère ainsi réticulé se solidifie en enfermant l’enzyme à l'intérieur de la capsule. Par la suite, les capsules enzymatiques sont utilisées pour donner au papier les propriétés de biocapteur. Afin d'immobiliser les capsules et l'enzyme sur le papier, une méthode courante dans l’industrie du papier connu sous le nom de couchage à lame est utilisée. Pour ce faire, les microcapsules sont mélangées avec une sauce de couchage qui sera appliquée sur des feuilles de papier. Les paramètres de viscosité i de la sauce et ceux du couchage ont été optimisés afin d'obtenir un couchage uniforme répondant aux normes de l'industrie. Les papiers bioactifs obtenus seront d'abord étudiés pour évaluer si les enzymes sont toujours actives après les traitements appliqués; en effet, tel que mentionné ci-dessus, les enzymes sont des substances très sensibles. Une enzyme très étudiée et qui permet une évaluation facile de son activité, connue sous le nom de laccase, a été utilisée. L'activité enzymatique de la laccase a été évaluée à l’aide des techniques analytiques existantes ou en proposant de nouvelles techniques d’analyse développées dans le laboratoire du groupe Rochefort. Les résultats obtenus démontrent la possibilité d’inclure des systèmes enzymatiques microencapsulés sur papier par couchage à lame, et ce, en utilisant des paramètres à grande échelle, c’est à dire des surfaces de papier de 0.75 x 3 m2 modifiées à des vitesses qui vont jusqu’à 800 m/min. Les biocapteurs ont retenu leur activité malgré un séchage par évaporation de l’eau à l’aide d’une lampe IR de 36 kW. La microencapsulation s’avère une technique efficace pour accroître la stabilité d’entreposage du biocapteur et sa résistance à l’exposition au NaN3, qui est un inhibiteur connu de ce biocapteur. Ce projet de recherche fait partie d'un effort national visant à développer et à mettre sur le marché des papiers bioactifs; il est soutenu par Sentinel, un réseau de recherche du CRSNG.

When Two Worlds Meet: A Response to Heesters

Commentaire / Commentary

STUDIES ON THE QUALITY AND PROCESS CONTROL FACTORS DURING THE PRODUCTION AND STORAGE OF SALTED DRIED FISH PRODUCTS

In this study the quality and process control factors during the production and storage of salted dried fish products. The study reveals that quantity of dry fish production in the state is decreasing and dry fish processing industry should be encouraged by central and state governments. The dry and wet salting may be carried out to a period of 4 to 8 hours respectively and time may depend on temperature, size, and concentration of medium. Demand is an unavoidable factor for sale of fish. The packed dry salted lots kept at room temperature are useful only for 20 days. The refrigerator- stored lots had more storage life and nutritional content are good up to 3 months. The cold storage stored dry salted lot had more storage life than the wet salted lot. The use of preservatives in salting is encouraged to reduce pH. The low temperature preservation maintains the nutritional value and quality for long period. It further encourages the labeling of nutritional value of dry fish as in tinned products.

Enhancement of Diffraction Efficiency and Storage Life of Poly (Vinyl Chloride) Based Optical Recording Medium with the Incorporation of an Electron Donor

The differaction efficiency,sensitivity and storage life of Methylene Blue sencitized poly (vinyl chloride) film was improved by the addition of an electron donor in the matrix. The addition of pyridine enhanced the diffraction efficiency by two times and storage life of the gratings was increased to 2-3 days.

Enhancement of Diffraction Efficiency and Storage Life of Poly (Vinyl Chloride) Based Optical Recording Medium with the Incorporation of an Electron Donor

The differaction efficiency,sensitivity and storage life of Methylene blue sensitized poly(vinyl chloride) film was improved by the addition of an electron donor in the matrix. The addition of pyridine enhanced the diffraction efficiency by two times and storage life of the gratings was increased to 2-3 days.

Changes in Protein, Carbohydrate and lipid content of cashew kernels during storage under two humidity conditions

The changes occuring to cashew kernels during storage at two humidity levels - 80% to 20% with respect to organoleptic characteristics, protein content, carbohydrate content, oil content, iodine and peroxide values were studied. From the present study it is concluded that organoleptic characteristics of cashew kernels deteriorates with increase in humidity. Decrease in protein and carbohydrate content of stored cashew kernel is dependent on humidity. Humidity increased oxidative rancidification.

Effect of the Vulcanization Time and Storage on the Stability and Physical Properties of Sulfur-Prevulcanized Natural Rubber Latex

Prevulcanized natural rubber latex was prepared by the heating of the latex compound at 55°C for different periods of time (2, 4, 6, 8, and 10 h). The changes in the colloidal stability and physical properties were evaluated during the course of prevulcanization. The prevulcanized latex compounds were stored for 300 days, and the properties were monitored at different storage intervals (0, 20, 40, 60, 120, 180, 240, and 300 days). During prevulcanization, the mechanical stability time increased, and the viscosity remained almost constant. The tensile strength increased during storage for a period of 20 days. The degree of crosslinking, modulus, elongation at break, and chloroform number were varied with the time of storage.

Influence of Processing Variables on Protein Quality and Frozen Storage Stability of Two Commercially Important Species of Squid (Loligo duvaucelii and Doryteuthis sibogae )

Cephalopods are utilized as an important food item in various countries because of its delicacy as raw consumed food. Mainly sepia and loligo are consumed raw by Japanese and Russians. The freshness of the products is very important when the product is consumed raw. The major species that dominate our squid catch are Loligo duvaucelii and Doryteuthis sibogae. There is a noticeable difference in the quality of both the species. The needle squid (Doryteuthis sibogae ) contributes about 35% of the total squid landing. Due to the fast deterioration , a major portion of the needle squid, which is caught during the first few hauls, is thrown back to sea. The catch in the last hauls only are taken to the landing centers. At present the needle squid is processed as blanched rings and the desired quality is not obtained if it is processed as whole, whole cleaned or as tubes. In this study an attempt is made to investigate the biochemical characteristics in both the species of squid in relation to their quality and, the process control measures to be adopted. The effect of various treatments on their quality and the changes in proteolytic and lysosomal enzymes under various processing conditions are also studied in detail.Thus this study can provide the seafood industry with relevant suggestions and solutions for effective utilization of both the species of squid with emphasis on needle squid.

Biochemical and Storage Characteristics of Myofibrillar Protein ( Surimi ) from Freshwater Major Carps

School of Industrial Fisheries, Cochin University of Science and Technology

Studies on Metallocene Polyolefin and Polyvinyl Chloride for Blood and Blood Component Storage Applications

Plasticized poly(vinyl chloride) (pPVC), although a major player in the medical field, is at present facing lot of criticism due to some of its limitations like the leaching out of the toxic plasticizer, di ethylhexyl phthalate (DEHP) to the medium and the emission of an environmental pollutant,dioxin gas,at the time of the post use disposal of PVC Products by incineration. Due to these reasons, efforts are on to reduce the use of pPVC considerably in the medical field and to find viable alternative materials. The present study has been undertaken in this context to find a suitable material for the manufacture of medical aids in place of pPVC. The main focus of this study has been to find out a non-DEHP material as plasticizer for pPVC and another suitable material for the complete repalcement of pPVC for blood/ blood component storage applications.Two approaches have been undertaken for this purpose-(1)the controversial plasticizer, DEHP has been partially replaced by polymeric plasticizers(2) an alternative material, namely, metallocene polyolefin (mPO) has been used and suitably modified to match the properties of flexible PVC used for blood and blood component storage applications.

Acid activated montmorillonite: an efficient immobilization support for improving reusability, storage stability and operational stability of enzymes

Three enzymes, α-amylase, glucoamylase and invertase, were immobilized on acid activated montmorillonite K 10 via two independent techniques, adsorption and covalent binding. The immobilized enzymes were characterized by XRD, N2 adsorption measurements and 27Al MAS-NMR spectroscopy. The XRD patterns showed that all enzymes were intercalated into the clay inter-layer space. The entire protein backbone was situated at the periphery of the clay matrix. Intercalation occurred through the side chains of the amino acid residues. A decrease in surface area and pore volume upon immobilization supported this observation. The extent of intercalation was greater for the covalently bound systems. NMR data showed that tetrahedral Al species were involved during enzyme adsorption whereas octahedral Al was involved during covalent binding. The immobilized enzymes demonstrated enhanced storage stability. While the free enzymes lost all activity within a period of 10 days, the immobilized forms retained appreciable activity even after 30 days of storage. Reusability also improved upon immobilization. Here again, covalently bound enzymes exhibited better characteristics than their adsorbed counterparts. The immobilized enzymes could be successfully used continuously in the packed bed reactor for about 96 hours without much loss in activity. Immobilized glucoamylase demonstrated the best results.