Complex regional pain syndrome type I (CRPS I, formerly known as reflex sympathetic dystrophy) is a painful neuropathic disorder that develops after trauma affecting the limbs without overt nerve ...injury. Clinical features are spontaneous pain, hyperalgesia, impairment of motor function, swelling, changes in sweating, and vascular abnormalities. In this study, the pathophysiological mechanisms of vascular abnormalities were investigated. Furthermore, the incidence, sensitivity and specificity of side differences in skin temperature were defined in order to distinguish patients with definite CRPS I from patients with extremity pain of other origin. In 25 CRPS I patients and two control groups (20 healthy subjects and 15 patients with other types of extremity pain), cutaneous sympathetic vasoconstrictor activity was altered tonically by the use of controlled thermoregulation. Whole-body temperature changes were induced with a thermal suit in which cold or hot water circulated. The vascular reflex response (skin blood flow, laser Doppler flowmetry, skin temperature, infrared thermometry) was analysed to quantify sympathetic outflow. Measurements were performed during a complete thermoregulatory cycle, i.e. during the entire spectrum of sympathetic vasoconstrictor activity from high (whole-body cooling) to low sympathetic activity (whole-body warming). Venous noradrenalin levels were determined bilaterally in five CRPS patients. (i) Three distinct vascular regulation patterns were identified related to the duration of the disorder. In the `warm' (acute) type of regulation, the affected limb was warmer and perfusion values were higher than in the contralateral limb during the entire spectrum of sympathetic activity. In the `intermediate' type of regulation the limb was either warmer or colder. In the `cold' (chronic) type of regulation, skin temperature and perfusion values were lower on the affected side during the entire spectrum of sympathetic vasoconstrictor activity. (ii) Noradrenalin levels were lower on the affected side, even in chronic patients with considerable cutaneous vasoconstriction. (iii) Temperature and blood flow differences between the two sides were dynamic and most prominent at a high to medium level of vasoconstrictor activity. (iv) In both control groups, there were only minor side differences in flow and temperature. In conclusion, it is suggested that, in CRPS I, unilateral inhibition of sympathetic vasoconstrictor neurones leads to a warmer affected limb in the acute stage. Secondary changes in neurovascular transmission may lead to vasoconstriction and cold skin in chronic CRPS I, whereas sympathetic activity is still depressed. Vascular abnormalities are dynamic. The maximal skin temperature difference that occurs during the thermoregulatory cycle distinguishes CRPS I from other extremity pain syndromes with high sensitivity and specificity.
There is an increasing need to test and evaluate the integrity of ageing components and structures in nuclear engineering. Since materials for nuclear applications are subjected to thermal, ...corrosive, tensile, and fatigue loads during their service life, a deep understanding of microstructural degradation is desirable, as it can be gained by nondestructive testing (NDT) methods.
In this study, an innovative fatigue testing setup and NDT methods are combined to develop new, efficient and reliable concepts to evaluate fatigue life and damage mechanisms. For this purpose, specimens of metastable austenitic stainless AISI 347 (X6CrNiNb18-10, 1.4550) steel, relevant for pipe components, are tested in a setup allowing in-situ measurement of temperature, micromagnetic, electric and electrochemical NDT parameters. Strain-controlled constant amplitude and strain-increase tests were performed and various physical measurements were applied for a fatigue life analysis by short-time evaluation procedures. In-situ NDT parameters are linked to the microstructural evolution of the metastable austenite during cyclic loading. Extensive microstructural analysis through methods like electron backscatter diffraction have been performed in initial condition to help understanding data development versus life time. It is shown that an advanced test setup based on micromagnetic and electrochemical measurements is suitable to indicate fatigue damage-related mechanisms in a metastable austenitic material. In the future, these methods and findings could enable mobile testing systems to evaluate components in service regarding their remaining fatigue life.
This paper presents the first output of the International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP), titled Methodology for Assessing Pipe Failure Rates in Advanced Water-Cooled ...Reactors (AWCRs), launched in 2018. This IAEA CRP is aimed at developing a good-practices document for estimating the probabilistic failure metrics of piping in AWCRs. The reliability of piping that comprise the Reactor Coolant Pressure Boundary (RCPB) is important for maintaining safe and stable operations of Nuclear Power Plants (NPPs) because failure of those piping components could lead to undesirable consequences, such as plant shutdown, costly repair, the occurrence of Loss-of-Coolant Accidents (LOCAs) and, possibly, subsequent core damage or large release events. Probabilistic failure metrics (e.g., failure rate, failure frequency, or failure probability) of RCPB components are the key inputs to the Probabilistic Safety/Risk Assessment (PSA/PRA) and risk management of NPPs. The estimation of probabilistic failure metrics, however, is challenging, especially for AWCRs, due to the lack of operating experience. Therefore, as the first step of the IAEA CRP activities, this paper is developed to provide a literature review of the existing studies (from 2000 to April 2019) on the estimation of probabilistic failure metrics for RCPB piping and Steam Generator (SG) tubes of NPPs and to categorize them based on four criteria: (1) explicitness of incorporation of physical failure mechanisms; (2) types of failure characterization; (3) types of physical models for degradation; and (4) explicitness of consideration of maintenance. The existing studies are also analyzed from the viewpoint of the following key aspects: (i) uncertainty analysis, (ii) sensitivity analysis, (iii) validation strategies, and (iv) the areas of applications.
•Existing studies on probabilistic failure metrics of piping and tubes are reviewed.•The existing studies are categorized based on a structured scheme.•Uncertainty/sensitivity analyses and validation strategies are also reviewed.•Practical application areas in the existing studies are summarized.
Pheromone 3 mRNA of the ciliate Euplotes octocarinatus contains three in-frame UGA codons that are translated as cysteines. This was revealed from cDNA sequencing and from plasma desorption mass ...spectrometry of cleaved pheromone 3 in connection with pyridylethylation of the fragments. N-terminal sequence analysis of carboxymethylated protein confirmed this conclusion for the first of the three UGA codons. Besides UGA the common cysteine codons UGU and UGC are also used to encode cysteine. UAA functions as a termination codon. No UAG codon was found. In connection with results reported for other ciliates, this suggests that the role of the classic termination codons had not yet been established when the ciliates started to diverge from other eukaryotes.
We have isolated and characterized the micronuclear gene encoding the regulatory subunit of cAMP-dependent protein kinase of the ciliated protozoan Euplotes octocarinatus, as well as its macronuclear ...version and the corresponding cDNA. Analyses of the sequences revealed that the micronuclear gene contains one small 69-bp internal eliminated sequence (IES) that is removed during macronuclear development. The IES is located in the 5′-noncoding region of the micronuclear gene and is flanked by a pair of tetra-nucleotide 5′-TACA-3′ direct repeats. The macronuclear DNA molecule carrying this gene is approximately 1400 bp long and is amplified to about 2000 copies per macronucleus. Sequence analysis suggests that the expression of this gene requires a +1 ribosomal frameshift. The deduced protein shares 31% identity with the cAMP-dependent protein kinase type I regulatory subunit of Homo sapiens, and 53% identity with the regulatory subunit R44 of one of the two cAMP-dependent protein kinases of Paramecium. In addition, it contains two highly conserved cAMP binding sites in the C-terminal domain. The putative autophosphorylation site ARTSV of the regulatory subunit of E. octocarinatus is similar to that of the regulatory subunit R44 of Paramecium but distinct from the consensus motif RRXSZ of other eukaryotic regulatory subunits of cAMP-dependent protein kinases.
This article presents the first output of the International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP), titled Methodology for Assessing Pipe Failure Rates in Advanced ...Water-Cooled Reactors (AWCRs), launched in 2018. This IAEA CRP is aimed at developing a good-practices document for estimating the probabilistic failure metrics of piping in AWCRs. The reliability of piping that comprise the Reactor Coolant Pressure Boundary (RCPB) is important for maintaining safe and stable operations of Nuclear Power Plants (NPPs) because failure of those piping components could lead to undesirable consequences, such as plant shutdown, costly repair, the occurrence of Loss-of-Coolant Accidents (LOCAs) and, possibly, subsequent core damage or large release events. Probabilistic failure metrics (e.g., failure rate, failure frequency, or failure probability) of RCPB components are the key inputs to the Probabilistic Safety/Risk Assessment (PSA/PRA) and risk management of NPPs. The estimation of probabilistic failure metrics, however, is challenging, especially for AWCRs, due to the lack of operating experience. Therefore, as the first step of the IAEA CRP activities, this paper is developed to provide a literature review of the existing studies (from 2000 to April 2019) on the estimation of probabilistic failure metrics for RCPB piping and Steam Generator (SG) tubes of NPPs and to categorize them based on four criteria: (1) explicitness of incorporation of physical failure mechanisms; (2) types of failure characterization; (3) types of physical models for degradation; and (4) explicitness of consideration of maintenance. The existing studies are also analyzed from the viewpoint of the following key aspects: (i) uncertainty analysis, (ii) sensitivity analysis, (iii) validation strategies, and (iv) the areas of applications.
Ciliates show two forms of reproduction: asexual (vegetative) and sexual reproduction (conjugation). Conjugation in
Euplotes octocarinatus is induced by pheromones secreted by cells of one mating ...type binding to corresponding receptors on cells of a different mating type. In this study, we used heterologously-expressed pheromone 2 (Phr2) in affinity chromatography to isolate pheromone 2 binding proteins in
Euplotes octocarinatus syngen 1. Using this approach, we isolated a 42-kDa protein (Phr2B) that bound Phr2. A tryptic fragment of Phr2B was used to construct degenerate oligonucleotides for PCR amplification of the macronuclear gene. The gene is predicted to encode a 58 amino acid protein. The N-terminus of the deduced protein shows significant similarity to membrane bound protein kinases of such diverse organisms as
Xenopus laevis,
Mus musculus and
Homo sapiens, while the C-terminus contains a region which is similar to an extracellular region within chemosensory receptors of
Caenorhabditis elegans. Western blotting analysis demonstrated that Phr2B specifically recognizes Phr2 and preliminary results indicate that antibodies raised against a C-terminal peptide of Phr2B inhibit cell mating. Further studies should be undertaken to investigate the precise role that Phr2B plays in preconjugative intercellular communication in
E. octocarinatus.
Two new stocks of the hypotrichous ciliate
Euplotes octocarinatus isolated in Florida and Maryland/USA were identified as members of mating type VI (mt
2mt
3), secreting pheromones 2 and 3 and mating ...type VII (mt
1mt
1), secreting pheromone 1. These are two out of the ten already known mating types of Euplotes octocarinatus. Results of breeding experiments suggest that the new stocks belong to new syngens of this species complex. The analysis of the macronuclear molecules containing the new pheromone 1, 2 and 3-encoding genes show that their structure is very similar to those isolated before. Like in these genes the coding regions are interrupted by three introns with a high degree of homology. A comparison of the deduced amino acid sequences of the new pheromones with the known versions of the corresponding pheromones reveals homologies of 76 to 93% for the secreted proteins whereas the leader sequences are 98 to 100% identical. In both versions of pheromones 1, 2 and 3 there are ten cysteine residues which are located at strictly conserved positions. In spite of their differences both versions of pheromones 1, 2 and 3 show the same specific biological activity. This might be an indication that the unchanged residues participate in receptor binding.
PDF
