18,269 research outputs found
Determination of organic acids evolution during apple cider fermentation using an improved HPLC analysis method
An efficient method for analyzing ten organic acids in food, namely citric, pyruvic, malic, lactic, succinic, formic, acetic, adipic, propionic and butyric acids, using HPLC was developed. Boric acid was added into the mobile phase to separate lactic and succinic acids, and a post-column buffer solution [5 mmol/L p-toluensulfonic acid (p-TSA) + 20 mmol/L bis (2-hydroxyethyl) iminotris (hydroxymethyl) methane (bisÂżtris) + 100 Âżmol/L sodium ethylenediaminetetraacetic (EDTA-2Na)] was used to improve the sensitivity of detection. The average spiked recoveries for the ten organic acids ranged from 82.9 to 127.9% with relative standard deviations of 1.44Âż4.71%. The linear ranges of determination were from 15 to 1,000 mg/L with correlation coefficients of 0.9995Âż0.9999. The metabolism of organic acids in cider, and the effect of nutrients including diammonium phosphate (DAP), thiamine, biotin, niacinamide and pantothenic acid on their metabolism, were studied using this method of analysis. We found that before cider brewing, additions of 200 mg/L DAP and 0.3 mg/L thiamine to apple juice concentrate results in a high quality cider
ECG R-R peak detection on mobile phones.
Mobile phones have become an integral part of modern life. Due to the ever increasing processing power, mobile phones are rapidly expanding its arena from a sole device of telecommunication to organizer, calculator, gaming device, web browser, music player, audio/video recording device, navigator etc. The processing power of modern mobile phones has been utilized by many innovative purposes. In this paper, we are proposing the utilization of mobile phones for monitoring and analysis of biosignal. The computation performed inside the mobile phone's processor will now be exploited for healthcare delivery. We performed literature review on RR interval detection from ECG and selected few PC based algorithms. Then, three of those existing RR interval detection algorithms were programmed on JavaTM platform. Performance monitoring and comparison studies were carried out on three different mobile devices to determine their application on a realtime telemonitoring scenario
An Astrometric Approach to Measuring the Color of an Object
The color of a star is a critical feature to reflect its physical property
such as the temperature. The color index is usually obtained via absolute
photometry, which is demanding for weather conditions and instruments. In this
work, we present an astrometric method to measure the catalog-matched color
index of an object based on the effect of differential color refraction (DCR).
Specifically, we can observe an object using only one filter or alternately
using two different filters. Through the difference of the DCR effect compared
with reference stars, the catalog-matched color index of an object can be
conveniently derived. Hence, we can perform DCR calibration and obtain its
accurate and precise positions even if observed with Null filter during a large
range of zenith distances, by which the limiting magnitude and observational
efficiency of the telescope can be significantly improved. This method takes
advantage of the DCR effect and builds a link between astrometry and
photometry. In practice, we measure the color indices and positions of Himalia
(the sixth satellite of Jupiter) using 857 CCD frames over 8 nights by two
telescopes. Totally, the mean color index BP-RP (Gaia photometric system) of
Himalia is 0.750 \pm 0.004 magnitude. Through the rotational phased color index
analysis, we find two places with their color indices exceeding the mean \pm 3
\sigma.Comment: 10 pages, 5 figures, 4 table
Weak anisotropy of the superconducting upper critical field in Fe1.11Te0.6Se0.4 single crystals
We have determined the resistive upper critical field Hc2 for single crystals
of the superconductor Fe1.11Te0.6Se0.4 using pulsed magnetic fields of up to
60T. A rather high zero-temperature upper critical field of mu0Hc2(0) approx
47T is obtained, in spite of the relatively low superconducting transition
temperature (Tc approx 14K). Moreover, Hc2 follows an unusual temperature
dependence, becoming almost independent of the magnetic field orientation as
the temperature T=0. We suggest that the isotropic superconductivity in
Fe1.11Te0.6Se0.4 is a consequence of its three-dimensional Fermi-surface
topology. An analogous result was obtained for (Ba,K)Fe2As2, indicating that
all layered iron-based superconductors exhibit generic behavior that is
significantly different from that of the high-Tc cuprates.Comment: 4 pages, 4 figures, submit to PR
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