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Average Variation (average + variation)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

DEVELOPMENT and EVALUATION of MICROWAVE HEATING of APPLE MASH AS A PRETREATMENT to PRESSING

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2004
J.S. ROBERTS
ABSTRACT Fuji, McIntosh, and Red Delicious apple mashes were heated in a 2450 MHz oven to achieve bulk temperatures of 40, 50, 60, and 70C. Three kilograms of mash at a depth of 0.016 m heated using 1500 W were the optimum parameters to heat apple mash in the microwave. Variety of the apple mash was shown not to have a significant effect on the heating performance. Comparing actual bulk temperature to the predicted bulk temperatures of 40, 50, 60, and 70C showed reproducibility of heating these mashes using microwave energy. Average variation between actual and predicted bulk temperatures were 1.48C for the Fuji mash, 0.98C for the McIntosh mash, and 1.13C for the Red Delicious mash. In addition, regional heating was investigated and four distinct regions of heating were observed: the corner, the edge, the middle, and the center. Color and moisture content of the mash were also measured and compared to unheated mash at 21C. [source]

Transitions of serum albumin in patients with glomerulosclerosis ,in vivo' characterization by electrophoretic titration curves

ELECTROPHORESIS, Issue 14 2006
Maurizio Bruschi
Abstract HSA functions as a physiological transporter of solutes and small molecules that induce structural transitions ,in vitro'. Analysis of these transitions requires prior purification of HSA that could introduce bias due to conformational changes. We utilized electrophoretic titration curves to describe a neutral to acid (N,A) transition of HSA directly in sera of seven patients with active focal segmental glomerulosclerosis (FSGS). The divergent electrophoretic profile of HSA was characterized by a shift in the range of pHs between 4.5 and 7.5 with an average variation of free electrophoretic mobility corresponding to loss of 1 positive charge in the pKa protonation range of histidyl residues and should involve domain I of HSA. ,In-gel' determination by maleimide-PEO2-biotin of free SH 34 of domain I showed inaccessibility of the dye at this site in pathological HSA and alkylation with the same complex induced N,A transition in normal HSA. Potential binders of free imidazoles such as Ca++ and/or of SH 34 such as NO were excluded on the basis of direct titration and studies on binding stimulation. This is the first report describing a transition of HSA directly ,in vivo', and the utilization of electrophoretic titration curves was critical to this purpose. This transition appears to be specific to FSGS and is unrelated to the nephrotic syndrome, Ca++ and NO binding. Spectroscopic analysis will elucidate the structural implication. [source]

A polymeric master replication technology for mass fabrication of poly(dimethylsiloxane) microfluidic devices

ELECTROPHORESIS, Issue 9 2005
Hai-Fang Li
Abstract A protocol of producing multiple polymeric masters from an original glass master mold has been developed, which enables the production of multiple poly(dimethylsiloxane) (PDMS)-based microfluidic devices in a low-cost and efficient manner. Standard wet-etching techniques were used to fabricate an original glass master with negative features, from which more than 50 polymethylmethacrylate (PMMA) positive replica masters were rapidly created using the thermal printing technique. The time to replicate each PMMA master was as short as 20 min. The PMMA replica masters have excellent structural features and could be used to cast PDMS devices for many times. An integration geometry designed for laser-induced fluorescence (LIF) detection, which contains normal deep microfluidic channels and a much deeper optical fiber channel, was successfully transferred into PDMS devices. The positive relief on seven PMMA replica masters is replicated with regard to the negative original glass master, with a depth average variation of 0.89% for 26 ,m deep microfluidic channels and 1.16% for the 90 ,m deep fiber channel. The imprinted positive relief in PMMA from master-to-master is reproducible with relative standard deviations (RSDs) of 1.06% for the maximum width and 0.46% for depth in terms of the separation channel. The PDMS devices fabricated from the PMMA replica masters were characterized and applied to the separation of a fluorescein isothiocyanate (FITC)-labeled epinephrine sample. [source]

Percentile-based spread: a more accurate way to compare crystallographic models

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2010
Edwin Pozharski
The comparison of biomacromolecular crystal structures is traditionally based on the root-mean-square distance between corresponding atoms. This measure is sensitive to the presence of outliers, which inflate it disproportionately to their fraction. An alternative measure, the percentile-based spread (p.b.s.), is proposed and is shown to represent the average variation in atomic positions more adequately. It is discussed in the context of isomorphous crystal structures, conformational changes and model ensembles generated by repetitive automated rebuilding. [source]