The characteristics are described of an antibody (designated L6) which has virtually absolute specificity for heptadecapeptide gastrin. This antibody binds G17, but does not bind peptide fragments or molecular forms of gastrin comprising G17 with either amino acid deletions, or additions, at the carboxyl- and amino-terminals. In serum from patients with Zollinger-Ellison syndrome the only form of gastrin revealed by L6 was compatible with G17, and there was good agreement between estimated G17 concentrations in serum analyzed by gel filtration and by direct radioimmunoassay using L6. Using L6 in conjunction with antibodies specific for carboxyl- and amino-terminals of G17 it has been possible to measure concentrations of different forms of gastrin in serum of normal subjects after a meal in greater detail than previously possible. After a light meal consisting of eggs, toast, and Oxo, serum concentrations of G17 measured by L6 increased to a peak 20 min after feeding (delta gastrin, 19 pmoles per liter; n = 17). In contrast, concentration of G34 peaked at 50 min (delta gastrin, 27 pmoles per liter). Small amounts of amino-terminal fragments of G17 were present throughout the digestive period. Applying the known ratio of biological potencies of G34 and G17 for stimulation of acid secretion in man, it is estimated that G17 accounts for about 75% of the biological activity in blood after a meal, even though G34 is present in higher molar concentrations. 相似文献
As part of the re-inspection of the reactor pressure vessel of the nuclear power plant, the low-frequency-eddy current technique was implemented during the 1995 outage. Since then, this inspection technique and the testing equipment have seen steady further development. Therefore, optimization of the entire testing system, including qualification based on the 1995 results, was conducted. The eddy current testing system was designed as a ten-channel test system with sensors having separate transmitter and receiver coils. The first qualification of the testing technique and sensors was performed using a single-channel system; a second qualification was then carried out using the new testing electronics. The sensor design allows for a simultaneous detection of surface and subsurface flaws. This assumes that testing is performed simultaneously using four frequencies. Data analysis and evaluation are performed using a digital multi-frequency regression analysis technique The detection limits determined using this technique led to the definition of the following recording limits for testing in which the required signal-to-noise ratio of 6 dB was reliably observed.
• Detection of surface connected longitudinal and transverse flaws:
• notch, 3 mm deep and 10 mm long, for weave bead cladding;
• notch, 2 mm deep and 20 mm long, for strip weld cladding.
• Detection of embedded planar longitudinal and transverse flaws:
• ligament of 7 mm for 8 mm clad thickness and 3 mm;
• ligament for 4 mm clad thickness, notch starting at the carbon steel base material with a length of 20 mm.
• Detection of embedded volumetric longitudinal and transverse flaws:
• 3 mm diameter side-drilled hole (SDH) for 8 mm clad thickness; ligament, 4 mm. For 4 mm clad thickness: diameter, 2 mm SDH; ligament, 2 mm. All SDHs are 55 mm deep.
Article Outline
1. Problem
2. Objective
3. Execution and results
3.1. Test instrument and electronics
3.2. Performance demonstration (qualification)
3.3. Summary of results and assessment of the qualification
3.4. Flaws open to the surface
3.5. Planar flaws in the cladding and sub-clad flaws
3.6. Volumetric flaws in the clad
3.7. Additional evaluations
4. Qualification results
5. Results from the 1999 outage
1. Problem
The reactor pressure vessel is equipped with a stainless steel (austenitic) cladding for corrosion protection. This cladding can only protect if no flaws are present at the surface or in the volume. The verification of the integrity of the cladding is currently conducted using state-of-the-art ultrasonic testing. Ultrasonic testing has an excellent capacity of proof for these types of flaws, but it generally cannot distinguish between flaws at the clad surface, in the clad volume, or at the clad-to-base material interface. Using the low-frequency (LF)-eddy current technique, these differences can be documented. For this reason, the LF-eddy current technique was developed and also supported by those who employ diverse testing technology in addition to ultrasonic testing for this type of testing.
2. Objective
The goal of the qualification described in this paper was the optimization and verification of the test procedure and test equipment based on the test systems currently used and, in addition, implementation of the results achieved with the newly built WS98 test electronics, a ten-channel eddy current testing system. The completion of the tasks should be performed in accordance with the ENIQ qualification guidelines. Following the successful qualification, the test system will be utilized during the 1999 reactor pressure vessel outage at the Stade nuclear power plant (KKS). The project started in August 1998, leaving approximately 6 months for the set-up of the equipment, system performance demonstration (qualification), and to compile the required documentation.
3. Execution and results
The following essential parameters for the qualification of the testing technique were determined by the test situation:
• sensor size of, maximum, 40 mm×40 mm×30 mm (L×W×H) for NF-absolute sensors;
• sensor size of, maximum, 60 mm×30 mm×30 mm for T/R sensors;
• frequency range, 0.5–20 kHz;
• effective coil width, ≥10 mm (6 dB drop);
• gain (amplification), up to 100 dB;
• long-term stability of the test instrument and electronics.
3.1. Test instrument and electronics
The eddy current instrument is designed for single-channel or multi-channel automated testing of the surface areas of piping systems, pressure vessels, and forgings for both mobile testing services in the field and also for use in stationary facilities in the area of manufacturing testing or inservice inspections.The instrument can easily be adapted to the requirements of the respective test situation due to its modular design. This is accomplished by increasing the testing electronics to the necessary number of sensor and/or frequency channels.The design of the eddy current electronics and the data flow can be seen in Fig. 1. 相似文献
The possibility of the translocation of the enzyme across the phospholipid bilayer membrane was investigated by using the liposomes prepared by 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in which beta-galactosidase (beta-gal) was entrapped. Exposing the POPC liposomes entrapping beta-gal inside to heat treatment (40-50 degrees C, 1-60 min) was found to induce its translocation across the liposome membrane. The translocated activity of beta-gal from inner to outer aqueous phase of liposomes indicated the maximal value when the liposomes entrapping beta-gal were heated at 45 degrees C for 30 min. The gel permeation profiles of the liposomes before and after heat treatment (45 degrees C, 30 min) also supported the translocation of beta-gal across the liposome membrane. The membrane fluidity of liposomes was found to be increased with increasing temperature, so that the hydrophobicity of liposome membrane was also increased. The local hydrophobicity of beta-gal was maximized at the temperature of 40-50 degrees C. The mechanisms of beta-gal translocation have been suggested to be triggered by the enhancement of hydrophobic interaction between the liposome surface and beta-gal molecules. Finally, a minimal scheme of possible mechanism on the heat-induced translocation of beta-gal has been presented on the basis of the hydrophobic interaction between the liposome and the proteins. The experimental data on the heat-induced translocation of beta-gal were well corresponding to those from model calculation. 相似文献
BACKGROUND: Questionnaire-based surveys from several countries have consistently detected adverse health associated with home dampness and mould growth. METHODS: To test the validity of questions commonly used to indicate the presence of indoor mould, questionnaires were administered in 403 homes where dust samples were taken for viable fungi and air samples for ergosterol. RESULTS: Geometric mean concentrations of the total viable fungi were 255 (SE 116) x 10(3) CFU/g when mouldy odours were reported and 155 (SE 55) when odours were not reported (P = 0.01). Similarly, reported water damage was associated with a 50% increase (P = 0.06). Geometric mean concentrations of the predominantly indoor-source fungi, Aspergillus plus Penicillium, were twice as high when mould or mildew was reported than when not mentioned (P = 0.01). The presence of reported mould or water damage was unrelated to the presence of detectable levels of ergosterol. There was evidence for reporting bias: in the presence of low concentrations of viable fungi in dust, respondents reporting allergies were more likely to report visible mould growth (odds ratio [OR] = 1.8, 95% confidence interval [CI]: 0.9-3.5, P = 0.10. In the presence of elevated concentrations of dust fungi, respondents who smoked were less likely to report visible mould growth, (OR = 0.4, 95% CI: 0.2-0.7, P = 0.005). CONCLUSIONS: Reported mould, water damage, and mouldy odours were associated with elevated levels of indoor fungi. However, inaccuracy was high and there was evidence of a systematic reporting bias. Future research should concentrate on developing accurate objective measures of exposure to fungi, and then use this information to develop valid questionnaires. Currently, objective measures not questionnaires, are recommended to clarify the health effects of indoor fungi. 相似文献
Endoscopic treatment of chronic pancreatitis has drawn benefits from endoscopic procedures previously described for the main bile duct. Endotherapy is developing throughout the world. Cyst drainage procedures certainly represent the largest step forward in that non-surgical approach, whatever it is either direct (through the stomach or the duodenum) or indirect through the papilla in the duodenum. This procedure gives similar results to surgery with a lower morbidity. Pancreatic duct drainage associated with stone clearance is feasible and provides good results which have not yet been compared with those obtained thanks to surgery. Nonetheless, when the duct is not widely dilated it has been proven to be a satisfactory alternative to surgery. By contrast, chronic cholestasis does not appear to be a good indication of endotherapy. 相似文献