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991.
The major risk factors and processing steps that can lead to contamination of green coffee with ochratoxin A (OTA) have been identified. Surveys of the green coffee production chain indicate that Aspergillus ochraceus and A. carbonarius are the most potent OTA producers on coffee. Both have been successfully grown in vitro on green coffee and coffee cherries, respectively, producing high amounts of OTA (5-13 mg kg -1 ). The so-called dry processing of coffee, which is cherry drying, was identified as one of the steps during which OTA formation can take place, particularly under humid tropical conditions. Cherries contain sufficient amounts of water to support mould growth and OTA formation during the initial 3-5 days of drying on the outer part of the cherries. Not surprisingly, after dehulling, husks can be highly contaminated with OTA, as also indicated by its enhanced concentration in soluble coffees adulterated with husks and parchment. A minimum water activity of 0.80 (about 14% MC) is required for in vitro OTA production on green coffee, a fact that does not rule out the possibility of OTA contamination due to improper transportation and storage of green coffee. However, this appears not to be a major route for OTA contamination of coffee. OTA contamination can clearly be minimized by following good agricultural practice and a subsequent post-harvest handling consisting of appropriate techniques for drying, grading, transportation and storage of green coffee; these procedures are well established. 相似文献
992.
993.
O. V. Mazurin M. V. Strel'tsina T. P. Shvaiko-Shvaikovskaya A. O. Mazurina 《Glass Physics and Chemistry》2002,28(5):271-280
The evolution of investigations into glass properties is described with the use of the SciGlass information system on the basis of an analysis of the world literature on glass from the end of the 19th century to the present day. Variations in the total amount of published data, in the interest of researchers in certain glass components and their properties, in the specific features of forming research groups, and in the general quality of publications are considered. Measures are proposed that can prevent a further decline in the quality of published experimental results. 相似文献
994.
995.
V. Recarte R. B. Pérez-Sáez J. San Juan E. H. Bocanegra M. L. Nó 《Metallurgical and Materials Transactions A》2002,33(8):2581-2591
The martensitic transformation temperatures and the types of martensitic phases have been determined in a wide concentration
range of technological interest for Cu-Al-Ni shape-memory alloys (SMAs) A stability diagram of martensitic phases as a function
of alloy concentration has been determined. It is found that when the aluminum content increases, the transformation changes
from β
3 ⇒ β′3 to β
3 ⇒ γ′3, with an intermediate concentration range where both martensites coexist due to a β
3 ⇒ γ′3+β′3 transformation. On the other hand, an increase of nickel content stabilizes the martensite β′3, changing from a mixed β
3 ⇒ γ′3 + β′3 to a single β
3 ⇒ β′3 transformation. Furthermore, linear relationships between M
s
and Al and Ni concentrations have been obtained for all types of martensitic phases. 相似文献
996.
997.
998.
A dyeing profile for a range of reactive dyes suitable for application to cellulosic knitwear is defined. Such a profile shows good level-dyeing, reproducibility and fastness properties together with potential for simplified dyeing processes. 相似文献
999.
An analysis is made of the fluid flows in a plane slot permeable channel. It is shown that for large numbers R (suction) self-similar solutions exist.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 3, pp. 432–436, September, 1985. 相似文献
1000.
Formal consideration of prior information on the Fourier amplitude of background contrast in an image, using the same Bayesian principles of statistical inference which underlie thermodynamics, allows one to subtract background without favoring only selected parts of frequency space. Without the bias in frequency space which causes periodicity bleeding and mars literal interpretation of Fourier-filtered images, the shape transform of aperiodic objects can be left intact. Algorithms for Bayesian background subtraction from one- and two-dimensional images are presented which further consider, in ad hoc fashion, one's uncertainty about background amplitude. The results help explain the reported success of Fourier truncation, and indicate that Bayesian background-subtracted images can minimize root-mean-square image error, as well as periodicity bleeding, in comparison to Fourier-filtered and Fourier-truncated alternatives. 相似文献