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Hybrid Design (hybrid + design)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Sequencing of real-world samples using a microfabricated hybrid device having unconstrained straight separation channels

ELECTROPHORESIS, Issue 21 2003
Shaorong Liu
Abstract We describe a microfabricated hybrid device that consists of a microfabricated chip containing multiple twin-T injectors attached to an array of capillaries that serve as the separation channels. A new fabrication process was employed to create two differently sized round channels in a chip. Twin-T injectors were formed by the smaller round channels that match the bore of the separation capillaries and separation capillaries were incorporated to the injectors through the larger round channels that match the outer diameter of the capillaries. This allows for a minimum dead volume and provides a robust chip/capillary interface. This hybrid design takes full advantage, such as sample stacking and purification and uniform signal intensity profile, of the unique chip injection scheme for DNA sequencing while employing long straight capillaries for the separations. In essence, the separation channel length is optimized for both speed and resolution since it is unconstrained by chip size. To demonstrate the reliability and practicality of this hybrid device, we sequenced over 1000 real-world samples from Human Chromosome 5 and Ciona intestinalis, prepared at Joint Genome Institute. We achieved average Phred20 read of 675 bases in about 70 min with a success rate of 91%. For the similar type of samples on MegaBACE 1000, the average Phred20 read is about 550,600 bases in 120 min separation time with a success rate of about 80,90%. [source]

OPTIMIZATION OF NEW FLOUR IMPROVER MIXING FORMULA BY SURFACE RESPONSE METHODOLOGY

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2010
RAOUDHA ELLOUZE GHORBEL
ABSTRACT In the present study, we search to improve the viscoelastic properties of wheat flour characterized by a low bread-making quality. Six regulators were tested: broad bean flour, gluten, monodiglyceride (MDG), ascorbic acid, sodium alginate and a mixture of amylase and xylanase. A hybrid design was carried out in order to study the effect of these regulators on the alveographic properties of wheat flour dough. Two alveographic responses (W: deformation energy and P/L: elasticity-to-extensibility ratio) were studied and simultaneously optimized via the desirability functions. An optimal mixture, containing 13.17 g/kg of broad bean flour, 15.13 g/kg of gluten, 0.155 g/kg of ascorbic acid, 3.875 g/kg of MDG, 2.75 g/kg of sodium alginate and 0.3 g/kg of enzyme mixture, was obtained and tested in a Tunisian flour. It led to a dough characterized by a W = 274 × 10,4 J and P/L = 0.74 versus 191 × 10,4 J and 0.40, respectively, for the Tunisian flour without improvers. PRACTICAL APPLICATIONS In this work, we developed a new flour improver mixing formula intended to be used with wheat flour characterized by a low bread-making quality. This improver mixture is in powder form and contains 13.17 g of broad bean flour, 15.13 g of gluten, 0.155 g of ascorbic acid, 3.875 g of monodiglyceride, 2.75 g of sodium alginate and 0.3 g of enzyme mixture per kilogram of wheat flour. The incorporation of this improver mixture in low bread-making quality wheatflour leads to an increase of its deformation energy (W) of about 43% and produces large volume bread. [source]

Sample size for post-marketing safety studies based on historical controls,

PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 8 2010
Yu-te Wu
Abstract Purpose As part of a drug's entire life cycle, post-marketing studies are an important part in the identification of rare, serious adverse events. Recently, the US Food and Drug Administration (FDA) has begun to implement new post-marketing safety mandates as a consequence of increased emphasis on safety. The purpose of this research is to provide exact sample size formula for the proposed hybrid design, based on a two-group cohort study with incorporation of historical external data. Methods Exact sample size formula based on the Poisson distribution is developed, because the detection of rare events is our outcome of interest. Performance of exact method is compared to its approximate large-sample theory counterpart. Results The proposed hybrid design requires a smaller sample size compared to the standard, two-group prospective study design. In addition, the exact method reduces the number of subjects required in the treatment group by up to 30% compared to the approximate method for the study scenarios examined. Conclusions The proposed hybrid design satisfies the advantages and rationale of the two-group design with smaller sample sizes generally required. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Optimal synthesis of p -xylene separation processes based on crystallization technology

AICHE JOURNAL, Issue 2 2009
Ricardo M. Lima
Abstract This article addresses the synthesis and optimization of crystallization processes for p-xylene recovery for systems with feed streams of high concentration, a case that arises in hybrid designs where the first step is commonly performed by adsorption. A novel superstructure and its corresponding mixed-integer nonlinear programming (MINLP) model are proposed. The distinct feature of this superstructure is the capability to generate optimum or near optimum flow sheets for a wide range of specifications of p-xylene compositions in the feed stream of the process. To cope with the complexity of the MINLP model, a two-level decomposition approach, consisting of the solution of an aggregated model and a detailed model, is proposed. The results obtained show good performance of the decomposition strategy, and the optimal flow sheets and p-xylene recoveries are in agreement with the results reported in patents. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source]