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161.
Maternal folate depletion during early development and high fat feeding from weaning elicit similar changes in gene expression,but not in DNA methylation,in adult offspring
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162.
Schaap M Schilham AM Zuiderveld KJ Prokop M Vonken EJ Niessen WJ 《IEEE transactions on medical imaging》2008,27(8):1120-1129
163.
Paumen ML Stol P Ter Laak TL Kraak MH Van Gestel CA Admiraal W 《Environmental science & technology》2008,42(9):3434-3440
This study aimed to monitor PAC availability to the oligochaete Lumbriculus variegatus during 28 days of exposure to spiked sediments, in order to obtain reliable chronic effect concentrations for reproduction. Sediment toxicity tests were performed using three pairs of PAC isomers: two homocyclic compounds (anthracene and phenanthrene), two azaarenes (acridine and phenanthridine), and the two main transformation products of the azaarenes (acridone and phenanthridone). During the experiment, available PAC concentrations in pore water (estimated using solid phase microextraction) decreased more than total PAC concentrations in the sediment. Relating effect concentrations to PAC concentrations in pore water and in organisms showed that the two homocyclic compounds caused narcotic effects during chronic exposure, but only one of the four tested heterocyclic PACs caused narcotic effects. The transformation product phenanthridone was not toxic at the tested concentrations (up to 4000 micromol/kg dry sediment), whereas EC50 values for the parent compound phenanthridine and the isomer acridone were below the estimated limit for narcosis, suggesting a specific mode of action. These results demonstrated the unpredictable (isomer) specific toxicity of azaarenes and their transformation products, emphasizing the need of chronic toxicity testing to gain insight into the long-term effects of heterocyclic PACs, which have been overlooked in risk assessment. 相似文献
164.
Milan Sernek Michiel Boonstra Antonio Pizzi Aurelien Despres Philippe Gérardin 《Holz als Roh- und Werkstoff》2008,66(3):173-180
Bonding of untreated, intermediate (hydro-thermolysed) and heat treated wood with melamine-urea-formaldehyde (MUF), phenol-resorcinol-formaldehyde (PRF) and polyurethane (PUR) adhesives was studied. An industrial heat treatment process (Plato ®) was used, which included two separate heat treatment stages and a drying stage in-between. Laminated beams having four lamellas were prepared from untreated and treated timber for mechanical testing of the bond lines. The results of the tests showed that heat treatment affected the shear strength and the delamination of the laminated wood depending on the adhesive system used for bonding. The PUR and MUF adhesives performed in a rather similar way, and better than the PRF adhesive. The shear strength of laminated wood bonded with the waterborne MUF and PRF adhesives decreased for the specimens made of hydro-thermolysed timber and decreased further for the specimens made of fully heat treated timber. The difference in adhesive bond shear strength between untreated, intermediate and fully treated wood was less obvious in the case of the PUR adhesive. Delamination of the PRF bond line decreased drastically for all the specimens made of heat treated timber. 相似文献
165.
Simonov AN Rombach MC 《Journal of the Optical Society of America. A, Optics, image science, and vision》2010,27(12):2563-2573
Asymptotic expressions are derived for the two-dimensional incoherent optical transfer function (OTF) of an optical system with defocus and spherical aberration. The two-dimensional stationary phase method is used to evaluate the aberrated OTF at large and moderately large defocus and spherical aberration. For small aberrations, the OTF is approximated by a power series in the aberration coefficients. An accurate approximation (in elementary functions) to the OTF is obtained for a defocused optical system with a circular pupil. We experimentally demonstrate the validity of the OTF approximations in sharp-focus image restoration from two defocused images. A digital focusing method is presented. 相似文献
166.
167.
Wouter De Cock Michiel Steyaert 《Analog Integrated Circuits and Signal Processing》2002,33(2):137-144
A 10 GHz fully integrated Voltage Controlled Oscillator is presented. A 29.7% tuning range is achieved from a 2.5 V power supply. The phase noise is –113 dBc/Hz at 600 kHz and –127 dBc/Hz at 3 MHz. The VCO is implemented in a 0.25 m 4 metal layer standard CMOS technology. This design will be used to discuss design and layout issues for high frequency LC-oscillators. A thorough analysis will be made of the contribution of the different building blocks to the performance of the total circuit. 相似文献
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169.
For many applications, the detection of water content in an oily base liquid is of crucial importance. Typical examples are automotive oils, e.g. engine and transmission oils, where water content in the order of a few percent needs to be detected. In this contribution, we analyze the suitability of permittivity and viscosity sensors for this application. It turns out, that permittivity sensors yield a clear indication of the water content in the oil being moreover to first order independent of the exact permittivity of the contaminating water. On the other hand, the output of microacoustic viscosity sensors, in contrast to conventional rotational rheometers, is hardly influenced by the water content as long as the droplet size is larger than the penetration depth of the evanescent microacoustic wave. Thus, they can be used for continued monitoring of the base oil’s viscosity even in case of an apparent water contamination. 相似文献
170.
This review examined whether Loevinger's measure of personality (ego) development is equivalent to the measurement of intelligence. The authors conducted a meta-analysis of 52 correlations between ego level scores and intelligence test scores (retrieved from 42 studies involving 5,648 participants). The weighted average correlation between ego level and intelligence ranged from .20 to .34, depending on the intellectual ability assessed (e.g., verbal intelligence). Adjusting for measurement unreliability increased these values only minimally. The authors also reviewed 16 studies that examined the association between ego level and various criterion variables (e.g., aggressive behavior) after statistically controlling for the effects of intelligence. Ninety-four percent of the tests revealed significant relations between ego level and criterion variables after controlling for intelligence, indicating that ego development and intelligence are not interchangeable constructs. These findings do not support recent speculations concerning the limited value of stage models of maturity, social development, and moral reasoning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献