Porous silicon-based nanostructured microparticles as degradable supports for solid-phase synthesis and release of oligonucleotides

ABSTRACT: We describe the preparation of several types of porous silicon (pSi) microparticles as supports for the solid-phase synthesis of oligonucleotides. The first of these supports facilitates oligonucleotide release from the nanostructured support during the oligonucleotide deprotection step while the second two types of supports are able to withstand the cleavage and deprotection of the oligonucleotides post synthesis and subsequently dissolve at physiological conditions (pH = 7.4, 37 oC), slowly releasing the oligonucleotides. Our approach involves the fabrication of pSi microparticles and their functionalisation via hydrosilylation reactions to generate a dimethoxytrityl (DMT) protected alcohol on the pSi surface as an initiation point for the synthesis of short oligonucleotides.     

Model for the differentiation of temperature and electric field effects during thermal assisted PEF processing

A model was developed that enables the quantification of thermal and electric field effects during the pulsed electric field (PEF) inactivation of alkaline phosphatase (ALP) and lactoperoxidase (LPO) in milk as well as Escherichia coli in apple juice.     

Comparison of the Emulsifying Properties of Fish Gelatin and Commercial Milk Proteins

ABSTRACT: We have compared the flocculation, coalescence, and creaming properties of oil-in-water emulsions prepared with fish gelatin as sole emulsifying agent with those of emulsions prepared with sodium caseinate and whey protein. Two milk protein samples were selected from 9 commercial protein samples screened in a preliminary study. Emulsions of 20 vol% n -tetradecane or triglyceride oil were made at pH 6.8 and at different protein/oil ratios. Changes in droplet-size distribution were determined after storage and centrifugation and after treatment with excess surfactant. We have demonstrated the superior emulsifying properties of sodium caseinate, the susceptibility of whey protein emulsions to increasing flocculation on storage, and the coalescence of gelatin emulsions following centrifugation.     

MODELLING OF SORPTION ISOTHERMS OF DRIED VEGETABLE WASTES FROM WHOLESALE MARKET

ABSTRACT

The moisture sorption isotherms of dried vegetable wastes (based on green leaves and fruits) from wholesale market were determined at 25, 40, 60 and 90°C by the static gravimetric method. Experimental data were fit by using several mathematical models. The G.A.B. and the Halsey model gave the minimum mean square error. G.A.B. parameters were related with temperature by Arrhenius expressions.     

Thermal and structural behavior of anhydrous milk fat. 2. Crystalline forms obtained by slow cooling.

The crystallization behavior of milk fat has been examined on slow cooling at 0.1 degrees C/min from 50 to -15 degrees C, to determine the variations of triacylglycerol organizations as a function of temperature. The experiments have been conducted with an instrument allowing coupled X-ray diffraction (XRD) at both small and wide angles and high-sensitivity differential scanning calorimetry (DSC) recordings from the same sample by taking advantage of the high-energy flux of a synchrotron. On slow cooling, milk fat triacylglycerols sequentially crystallize in four different lamellar structures with double-chain length of 41.5, 48.3, and 39.2 A and a triple-chain length of 62.2 A stackings. Simultaneous wide-angle XRD has shown that initial nucleation occurs in a packing of beta' type at about 24 degrees C. For temperature < 13 degrees C, triacylglycerols crystallize in an hexagonal subcell of alpha type, leading to the coexistence of the beta' + alpha polymorphic forms, which is recorded until -15 degrees C. Thermal analysis allowed to correlate the formation of the different crystalline species monitored by XRDT (XRD as a function of temperature) to the exothermal events recorded simultaneously by differential scanning calorimetry. The evolution of the species formed during crystallization was also monitored on heating at 2 degrees C/min. The absence of polymorphic evolution on heating, as well as the high final melting point observed, about 40 to 41 degrees C, confirmed that cooling at 0.1 degrees C/min leads to quasi equilibrium.     

Mechanical properties of hybrid fiber reinforced lightweight aggregate concrete made with natural pumice

The purpose of this study is to improve the ductility of pumice lightweight aggregate concrete by incorporating hybrid steel and polypropylene fibers. The changes in mechanical properties and also bulk density and workability of pumice lightweight aggregate concrete due to the addition of hybrid steel and polypropylene fibers have been studied. The properties were investigated include bulk density and workability of fresh concrete as well as compressive strength, flexural tensile strength, splitting tensile strength and toughness of hardened concrete. Nine concrete mixtures with different volume fractions of steel and polypropylene fibers were tested. A large increase in compressive and flexural ductility and energy absorption capacity due to the addition of steel fibers was observed. Polypropylene fibers, on the other hand, caused a minor change in mechanical properties of hardened concrete especially in the mixtures made with both steel and polypropylene fibers. These observations provide insight into the benefits of different fiber reinforcement systems to the mechanical performance of pumice lightweight aggregate concrete which is considered to be brittle. These results provide guidance for design of concrete materials with reduced density and enhanced ductility for different applications, including construction of high-rise, earthquake-resistant buildings.     

Multi-robot multiple hypothesis tracking for pedestrian tracking

In this paper the problem of tracking walking people with multiple moving robots is tackled. For this purpose we present an adaptation to the Multiple Hypothesis Tracking method, which unlike classic MHT, allows for one-to-many associations between targets and measurements in each hypothesis production cycle and is thus capable of operating in a scenario involving multiple sensors. Derivation of hypotheses probabilities accounts for the continuously changing overlapping areas in fields of view of the robots sensors and for detection uncertainty. In the context of three experiments involving people walking among moving robots, the successful integration of our tracking algorithm to a real-world setup is assessed.