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21.
Frédéric Debode Eric Janssen Gilbert Berben 《European Food Research and Technology》2007,226(1-2):273-280
In this paper, four different physical treatments (microwaves, heating by conduction, sonication and pressure autoclaving)
were performed to degrade a pure DNA extract, and their influence on GMO quantification was studied. The aim was to check
the hypothesis that processing of agrofood products results in a similar degradation rate for both the transgenic target and
the specific target. Indeed we could observe that even if the used physical treatments could lead to a significant increase
of C
t values for both transgenic and specific targets, the resulting ΔC
t remained stable. So, the main conclusion of the study is that the aforementioned hypothesis seems valid and thus a physical
degradation of DNA will not affect the relative quantitation of the GMO content, provided that both the specific and transgenic
targets have very similar size. A second important issue of the experiments performed was that DNA is a very robust molecule
as it is extremely difficult to reach a mean size below 100 bp. The study also gives evidence of the importance of using small
targets. 相似文献
22.
Effect of melt spinning on the microstructure and mechanical properties of three Ni-base superalloys
A microstructural and mechanical analysis was performed on three rapidly solidified nickel base superalloys. Transmission
and scanning electron microscopy along with tensile tests were performed on the ribbons in the as-cast and aged condition.
This investigation permitted a correlation to be made between cooling rate, microstructure, and mechanical properties. It
was found that melt spinning significantly altered the physical characteristics of the alloys studied. The rapid cooling rates
(∼107 K/s) produced ribbons with a low dislocation density and small (∼1 μm) low angle cells. The precipitation of γ′ was suppressed,
producing alloys with a smaller volume fraction of precipitates and lower APBE than in the conventionally cast condition.
Also, the matrix/precipitate lattice mismatch was higher in the melt spun foils. Tensile strengths were similar to those in
the conventional form; however, no measurable ductility was present. Aging the ribbons resulted in increases in γ′ volume
fraction, tensile strengths, APBE, and elongations compared to the as-cast ribbons. The results of this work suggest that
many of the microstructural refinements produced by melt spinning are lost after a short aging time at moderate temperatures. 相似文献
23.
Floccia Caroline; Goslin Jeremy; Girard Frédérique; Konopczynski Gabrielle 《Canadian Metallurgical Quarterly》2006,32(5):1276
The processing costs involved in regional accent normalization were evaluated by measuring differences in lexical decision latencies for targets placed at the end of sentences with different French regional accents. Over a series of 6 experiments, the authors examined the time course of comprehension disruption by manipulating the duration and presentation conditions of accented speech. Taken together, the findings of these experiments indicate that regional accent normalization involves a short-term adjustment mechanism that develops as a certain amount of accented signal is available, resulting in a temporary perturbation in speech processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
24.
Summary
We report the synthesis of some new backbone fluorinated
polymers of the poly(phenylenevinylene) type. The new polymers
were characterised by NMR, SEC and X-ray powder diffraction. The
charge carrier mobilities were determined using pulse radiolysis
time resolved microwave conductivity (PR-TRMC) and the carrier
mobilities were compared to the similar non-fluorinated
analogues. The changes in charge carrier mobilities as a
function of molecular substitution pattern is discussed in terms
of other materials properties such as electronic structure and
absorption properties. The major result is that it was found
possible for this type of material to alter the electronic
energy levels by molecular substitution without imparting
significant changes in the magnitude of the charge carrier
mobilities and the optical properties. 相似文献
25.
De Fruyt Filip; Van Leeuwen Karla; Bagby R. Michael; Rolland Jean-Pierre; Rouillon Frédéric 《Canadian Metallurgical Quarterly》2006,18(1):71
Structural, mean- and individual-level, differential, and ipsative personality continuity were examined in 599 patients treated for major depression assigned to 1 of 6 forms of a 6-month pharmaco-psychotherapy program. Covariation among traits from the Five Factor model remained invariant across treatment, and patients described themselves as slightly more extraverted, open to experience, agreeable and conscientious, and substantially more emotional stable after treatment. Trait changes were only to a small extent explained by changes in depression severity. There was evidence for differential, individual-level, and ipsative stability, with stable personality profiles in terms of shape and to a lesser extent in terms of scatter and elevation. Traits remain relatively stable, except for emotional stability, despite the depressive state and the psychopharmacological interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
26.
Summary Systems of poly(ethylene oxide)/polystyrene and of poly(ethylene oxide)/poly(styrene-co-acrylic acid) of different ratios
were studied by inverse gas chromatography using benzene and n-decane as molecule probes and by viscosimetry in tetrahydrofuran.
The transition temperatures as shown in the retention diagrams and the interaction parameters as determined by inverse gas
chromatography and by viscosimetry showed that whereas poly(ethylene oxide) is incompatible with polystyrene, the introduction
of amounts of acrylic acid groups into polystyrene chains by free radical copolymerization led to compatible systems of the
acidic copolymer with the poly(ethylene oxide). 相似文献
27.
Kubinyi Enik?; Topál József; Miklósi ádám; Csányi Vilmos 《Canadian Metallurgical Quarterly》2003,117(2):156
Eighty-seven pet dogs (Canis familiaris) were involved in an experiment in which they had to solve a task to obtain a ball. After witnessing a full demonstration by their owner (10 times pushing the handle of the box, which released a ball), most dogs preferred to touch the handle sooner and more frequently in comparison with other parts of the box, and they used the handle to get the ball. In contrast dogs in 3 control groups developed their own respective methods. The lack of emergence of the ball and playing after the demonstration did not affect the learning performance strongly. This suggests that in dogs the outcome of a demonstration plays only a restricted role in the manifestation of social learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
It is well known that horizontal surfaces of high strength concrete (HSC) are susceptible to cracking in the time before and
during setting. It appears that there are two critical time periods for such cracking: An early period ranging from placing
to an hour or two, and a late period that covers the setting time and early hardening. The latter is considered here. In this
period, the cracking risk may be assessed from the ratio between strain (the volume change) and tensile strain capacity, or
from the ratio between stress generated from the volume change at restraint, and the tensile strength. All these parameters
were measured. It is shown that relatively moderate volume changes of HSC-surfaces caused by drying plus cooling, generate
restraining stress that may exceed the tensile strength, and thus, generate failure. The results indicate that crack risk
assessment from stress/strength is more reliable than using strain/strain capacity. The starting point of tensile strength
evolution of hardened concrete seems to coincide fairly well with the initial setting time. Also, the tensile strain capacity
reaches a low level at this point, but continues descending for another hour or more. 相似文献
29.
An executable subset of VDM-SL in an SA/RT framework 总被引:2,自引:2,他引:0
In this article we present the executable specification language IPTES Meta-IV based on the formal specification language VDM-SL. The language has been fitted to work in an SA/RT framework and the article presents how it supports the specification of the data transformation part of SA/RT. Furthermore we present some of the advanced constructs of the language seen as an executable specification language in its own right. Finally we present how an IPTES Meta-IV interpreter is used in combination with a high-level timed Petri net executor to execute SA/RT models. 相似文献
30.
A. K. Dahle P. A. Tøndel C. J. Paradies L. Arnberg 《Metallurgical and Materials Transactions A》1996,27(8):2305-2313
The effect of grain refinement on the fluidity of AlSi7Mg and AlSi11Mg has been investigated by spiral tests. Two different
types of grain refiners have been evaluated. An AlTi5Bl master alloy was added to different Ti contents. Since the commercial
alloys had a high initial content of titanium, model alloys were made to investigate the fluidity at low grain refiner additions.
Commercial alloys grain refined only by boron additions have also been investigated. The results from the fluidity measurements
have been verified by measuring the dendrite coherency point of the different cast alloys. Although different, the two methods
show similar trends. The spirals from each fraction grain refiner cast were subsequently investigated metallographically at
the tip of the spirals and at a reference point a distance behind, but no obvious difference in structure was observed. For
both alloys, an increase in fluidity is observed as the content of grain refiner increases above 0.12 pct Ti, while the fluidity
is impaired with increased grain refinement below 0.12 pct Ti. The alloys grain refined with ~0.015 pct B show the highest
fraction solid at dendrite coherency, the smallest grain size, and the best fluidity. 相似文献