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121.
122.
Ramsés Fuenmayor 《Systemic Practice and Action Research》1990,3(6):525-544
This paper is the first in a trilogy which intends to discuss the notion of critique within two different contexts: Modern Western Philosophy and Contemporary Systems Thinking. This first paper presents a phenomenological inquiry into the concept of “critique.” The result of the inquiry is a model of the possibilities ofcritique which is used to interpret four “moments” of critique in Modern Western Philosophy. 相似文献
123.
Mild acidic treatment increases the rheumatoid factor titre of some sera and synovial fluids (SF) in rheumatoid arthritis (RA), juvenile RA (JRA) and most frequently in rheumatoid vasculitis. This unmasking of 'hidden' RF in serum and SF samples correlated with the RF-immune complexes (RF-IC) and complexed C4 present in the 3% polyethylene glycol (PEG) precipitates, indicating that by means of 'hidden' RF measurements RF-ICs are possibly detected. This method seems to provide a diagnostic tool for detecting RF-ICs in RA and other related diseases. 相似文献
124.
125.
Miklós Rédei Iñaki San Pedro 《Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics》2012,43(2):84-89
We distinguish two sub-types of each of the two causality principles formulated in connection with the Common Cause Principle in Henson (2005) and raise and investigate the problem of logical relations among the resulting four causality principles. Based in part on the analysis of the status of these four principles in algebraic quantum field theory we will argue that the four causal principles are non-equivalent. 相似文献
126.
Systemic Practice and Action Research - The presentation of a Systems Approach made by Churchman in 1968 starts from a close link between a systems approach and tackling world problems. The link is... 相似文献
127.
Sergio Porté Agrin Moeini Irene Reche Naeem Shafqat Udo Oppermann Jaume Farrés Xavier Parés 《Cellular and molecular life sciences : CMLS》2011,68(6):1065-1077
Human ζ-crystallin is a Zn2+-lacking medium-chain dehydrogenase/reductase (MDR) included in the quinone oxidoreductase (QOR) family because of its activity
with quinones. In the present work a novel enzymatic activity was characterized: the double bond α,β-hydrogenation of medium-chain
2-alkenals and 3-alkenones. The enzyme is especially active with lipid peroxidation products such as 4-hydroxyhexenal, and
a role in their detoxification is discussed. This specificity is novel in the QOR family, and it is similar to that described
in the distantly related alkenal/one reductase family. Moreover, we report the X-ray structure of ζ-crystallin, which represents
the first structure solved for a tetrameric Zn2+-lacking MDR, and which allowed the identification of the active-site lining residues. Docking simulations suggest a role
for Tyr53 and Tyr59 in catalysis. The kinetics of Tyr53Phe and Tyr59Phe mutants support the implication of Tyr53 in binding/catalysis
of alkenal/one substrates, while Tyr59 is involved in the recognition of 4-OH-alkenals. 相似文献
128.
One of the most important issues to resolve in parts manufactured from rapid manufacturing (RM) technologies is to know their behavior working under real conditions. Total quality manufacturing (TQM) is only possible if mechanical properties are well known in the design stage depending on the processing parameters. This work is mainly focused on testing of several samples made with different selective laser sintering (SLS) parameters and technologies. This procedure is the starting point to establish a basis for designing for RM and the standardization of RM testing. The experiments and the analysis of variance (ANOVA) analyzed the effects of several factors on mechanical properties. The SLS technologies were 3DSystem and EOS. The results show which factor has a large effect on the variables and the interaction between them. The conclusions are very useful for developing rules for designing (designing for RM) and creating new standard rules (ISO, AISI, and DIN) for RM materials and parts testing. The ANOVA gives a better knowledge of the effects of these factors and eliminates unimportant parameters. 相似文献
129.
Subthreshold Na+-dependent theta-like rhythmicity in stellate cells of entorhinal cortex layer II 总被引:13,自引:0,他引:13
The oscillation of membrane potential in mammalian central neurons is of interest because it relates to the role of oscillations in brain function. It has been proposed that the entorhinal cortex (EC), particularly the stellate cells of layer II (ECIIscs), plays an important part in the genesis of the theta rhythm. These neurons occupy a key position in the neocortex-hippocampus-neocortex circuit, a crucial crossroad in memory functions. Neuronal oscillations typically rely on the activation of voltage-dependent Ca2+ conductances and the Ca2+ -dependent K+ conductance that usually follows, as seen in other limbic subcortical structures generating theta rhythmicity. Here we report, however, that similar oscillations are generated in ECIIscs by a Na+ conductance. The finding of a subthreshold, voltage-gated, Na+ -dependent rhythmic membrane oscillation in mammalian neurons indicates that rhythmicity in heterogeneous neuronal networks may be supported by different sets of intrinsic ionic mechanisms in each of the neuronal elements involved. 相似文献
130.
Histone H3 lysine 9 methylation is an epigenetic imprint of facultative heterochromatin. 总被引:20,自引:0,他引:20
Antoine H F M Peters Jacqueline E Mermoud Dónal O'Carroll Michaela Pagani Dieter Schweizer Neil Brockdorff Thomas Jenuwein 《Nature genetics》2002,30(1):77-80
Post-translational modifications of histone amino termini are an important regulatory mechanism that induce transitions in chromatin structure, thereby contributing to epigenetic gene control and the assembly of specialized chromosomal subdomains. Methylation of histone H3 at lysine 9 (H3-Lys9) by site-specific histone methyltransferases (Suv39h HMTases) marks constitutive heterochromatin. Here, we show that H3-Lys9 methylation also occurs in facultative heterochromatin of the inactive X chromosome (Xi) in female mammals. H3-Lys9 methylation is retained through mitosis, indicating that it might provide an epigenetic imprint for the maintenance of the inactive state. Disruption of the two mouse Suv39h HMTases abolishes H3-Lys9 methylation of constitutive heterochromatin but not that of the Xi. In addition, HP1 proteins, which normally associate with heterochromatin, do not accumulate with the Xi. These observations suggest the existence of an Suv39h-HP1-independent pathway regulating H3-Lys9 methylation of facultative heterochromatin. 相似文献