Concept and procedure of the IRC test for assessing hydrogen assisted weld cracking

The self restraining Instrumented Restraint Cracking (IRC)-test enables the determination of weld joint reaction forces and -moments responsible for hydrogen assisted cracking. With help of continuous measurements during cooling of the weld, the effects of crack inducing parameters can be detected in detail. The IRC-test can be applied to procedure development and procedure qualification welding, making use of current fabrication practice at restraint intensities of the to-be-fabricated structure. It is easy to carry out and the results are quickly at hand.     

Kristallseigerungen und eutektische Carbidausscheidungen in Eisen-Kohlenstoff-Wolfram-Legierungen

Untersuchungen zur Kristallseigerung und Primärcarbidausscheidung von Eisen-Kohlenstoff-Wolfram-Legierungen mit 0,5 bis 2,2% C und 1,0 bis 12,4% W sowie < 0,35% Si, < 0,55% Mn, < 0,03% P und < 0,04% S. Aussagen über die Kristallseigerung des Wolframs in Abhängigkeit vom Kohlenstoffgesamtgehalt bis zum Erreichen der Carbidsättigung der Mischkristalle. Zusammenhang zwischen dem Anteil an Primärcarbiden und wachsenden Kohlenstoffgesamtgehalten bei konstantem Wolframgehalt. Ermittlung unterschiedlich hoher Anteile der beiden Carbide M₆C und M₃C. Einfluß einer Homogenisierung auf die Beseitigung der Kristallseigerung und die Ausscheidung wolframreicher Carbide.     

Heterogeneous phase equilibria as a basis for crevice corrosion modelling

The presented crevice corrosion model is intended to provide basic understanding of formation and dissolution of passivating layers during time dependent metal dissolution in an already deoxygenated crevice. It operates along a constant cathodic polarization curve in subsequent time steps with time dependent anodic polarization curves and corrosion currents. The anodic polarization curves are determined by dissoluted ionic chromium and respective Nernst potentials as well as by the mass of precipitated passivating chromiumhydroxide layers. All chemical reactions including diffusion of chloride into the model crevice configuration are assumed to be at equilibrium during the respective time steps. The amounts of passivating chromiumhydroxide masses are determined by lever-rule application at increasing chromium and chloride contents in aquaeous solution of the quaternary water-chromium-hydrogen-chloride phase diagram at various Nernst potentials. For this purpose, the established water–chromium Pourbaix diagram had to be redrawn in terms of ternary water-chromium-hydrogen phase diagrams for constant potentials. It was tentatively extended to the quaternary chloride including diagram based on literature results. This included solubility of chromiumchloride in hydrochloric acid and most probable effects of chloride ions on chromiumhydroxide solubility at saturation with chromium metal. The results of the interactive corrosion process are based on a crevice geometry drawn from previous publications and given initial solution concentrations as well as assumed polarization curves for time steps of one second. It is shown, how the process starts with concentration changes of chromium, chloride and hydrogen in the crevice, the subsequent formation of the passive layer and the corresponding decrease in the corrosion current and increase in the mixed potentials. In the presence of the chromiumhydroxide phase, however, chromium and hydrogen remain at low levels in the equilibrium aqaeous solution while chloride is increasing. The saturated solution reaches the four phase equilibrium concentration including saturation by chromium, chromiumhydroxide and chromiumchloride at corresponding Nernst potentials. The further increase in total chromium and chloride concentrations of the crevice then leads to initiation and propagation of crevice corrosion by formation of non-passivating chromiumchloride at the expence and finally, the total dissolution of passivating chromiumhydroxide, at decreasing mixed potentials and increasing currents. Due to the low solubility of chromiumchloride in hydrochloric acid, the latter is finally formed with the result of the well-known increase in crevice acidity. Thus, it is demonstrated that the acidification itself is not a requirement for crevice corrosion but rather a consequence of it.     

Specific Targeting of Antiapoptotic Bcl-2 Proteins as a Radiosensitizing Approach in Solid Tumors

Avoidance of therapy-induced apoptosis is a hallmark of acquired resistance towards radiotherapy. Thus, breaking resistance still challenges modern cancer therapy. The Bcl-2 protein family is known for its regulatory role in apoptosis signaling, making Bcl-2, Mcl-1 and Bcl-x_L promising targets. This study evaluates the effects of highly specific inhibitors for Bcl-x_L (WEHI-539), Bcl-2 (ABT-199) and Mcl-1 ({"type":"entrez-nucleotide","attrs":{"text":"S63845","term_id":"400540","term_text":"S63845"}}S63845) as radiosensitizers. Covering a broad spectrum of solid tumors, Non-Small-Cell Lung Cancer (NSCLC), Head and Neck Squamous Cell Carcinoma (HNSCC) and synovial sarcoma cell lines were exposed to fractionated radiation as standard therapy with or without Bcl-2 protein inhibition. Protein expression was detected by Western blot and cell death was assessed by flow cytometry measuring apoptosis. In contrast to NSCLC, a high level of Bcl-x_L and its upregulation during radiotherapy indicated radioresistance in HNSCC and synovial sarcoma. Radioresistant cell lines across all entities benefited synergistically from combined therapy with Bcl-x_L inhibition and fractionated radiation. In NSCLC cell lines, Mcl-1 inhibition significantly augmented radiotherapy independent of the expression level. Our data suggest that among antiapoptotic Bcl-2 proteins, targeting Bcl-x_L may break resistance to radiation in HNSCC, synovial sarcoma and NSCLC in vitro. In NSCLC, Mcl-1 might be a promising target that needs further investigation.     

Subacute myocardial infarction: assessment by STIR T2-weighted MR imaging in comparison to regional function

Purpose Increased T2 signal intensity (SI) can be regularly observed in myocardial infarction. However, there are controversial reports about the relationship of elevated T2 SI to myocardial viability and some authors propose that high T2 SI serves as a sign of irreversible myocardial injury. This study investigates increased T2 SI compared to myocardial function in patients with reperfused subacute myocardial infarction. Preserved function was used as criterion for viability. Methods Ten healthy volunteers and 17 patients with myocardial infarction and patent inlarct related coronary artery were examined on a 1.5 T Magnetom Vision system (Siemens). For T2-weighted MR imaging a breath-hold STIR sequence with dark-blood preparation was used. Cine FLASH 2D imaging was applied to assess myocardial function. Signal-to-noise (S/N) in STIR T2 images was measured in normal and infarcted regions and subsequently identified by two independent observers. Based on a 20 segment model of the left ventricle findings were compared to regional myocardial function. Results Elevated STIR T2 SI was found in all 17 patients and observed in 27% (204/754) of segments. S/N of normal myocardium was 5.1 ±0.7 in volunteers and 4.9 ± 0.8 in patients(P=NS). Infarcted myocardium presented with significantly-increased S/N 12.8 ± 1.9 (P < 0.0001). Significant transmural elevation of T2 SI was noted in 32% of segments with preserved systolic function. Conclusion Increased STIR T2 SI can be observed transmurally in post-ischemic myocardial regions with preserved function. It therefore cannot be used as an exclusive marker for the non-viable region.     

Allergenicity of proteolytic hydrolysates of the soybean 11S globulin

ABSTRACT:  A substantial portion of the human population has immune hypersensitivities to various food materials. Soybean is one of the most common foods involved in such hypersensitivity reactions, especially in younger children. In this study, we investigated the effect of peptic and chymotryptic hydrolysis on the allergenicity of the 11S soybean globulin, which is the primary soybean allergen. The 11S globulin is composed of both acidic and basic polypeptides, and we found that the acidic polypeptide was effectively hydrolyzed, while basic polypeptide was more resistant to hydrolysis. The 11S globulin hydrolysate was size-fractionated by gel filtration, and 9 of the fractions obtained were tested for allergenicity against sera from 6 soybean-allergenic patients. The overall allergenicity of soybean 11S globulin was reduced by peptic and chymotryptic hydrolysis, although a gel filtration fraction with a major peptide of 20 kDa was highly immunoreactive. Hydrolyzed fragments of less than about 20 kDa were not immunoreactive.     

Effect of prepartum maternal energy density on the growth performance, immunity, and antioxidation capability of neonatal calves

This study investigated the effect of prepartum diets differing in energy density on growth performance, immunity, and antioxidation capability of neonatal calves. Thirty Holstein dairy cows were allocated at random into 3 groups: low energy group [L; net energy of lactation (NE(L))=5.25 MJ/kg of dry matter (DM)]; medium energy group (M; NE(L)=5.88 MJ/kg of DM); and high energy group (H; NE(L)=6.48 MJ/kg of DM) at d 21 prepartum. Plasma was sampled for analysis of glucose, total protein, β-hydroxybutyrate, and nonesterified fatty acids at 21, 14, and 7 d before parturition. After calving, birth weight and measurements of the calves in each group were recorded, and blood samples were collected for analysis of CD4, CD8, CD21, IL-2, IL-4, IL-6, total antioxidant capacity, superoxide dismutase, glutathione peroxidase, and maleic dialdehyde. The results indicated that although maternal weight did not differ among L, M, and H groups at 21, 14, and 7 d before parturition, the concentrations of glucose and β-hydroxybutyrate at 14 and 7 d in the L group were decreased compared with that in the H group. In addition, nonesterified fatty acids concentrations increased significantly in the L group at 14 and 7 d before parturition compared with that in the M and H groups. Birth weight, body height, body length, abdominal circumference, thoracic girth, umbilical girth, and levels of CD4, CD4:CD8, IL-2, IL-4, total antioxidant capacity, and superoxide dismutase were decreased in calves of the L group compared with those of the H group. For the M group, CD4, CD4:CD8, and superoxide dismutase were decreased; and in the L group glutathione peroxidase and maleic dialdehyde levels were significantly increased compared with those of the H group. Reducing the maternal energy density during the last 21 d before parturition had a negative effect on growth and development, immunity, and antioxidation capability of neonatal calves.     

Methods of investigating the solvability of systems of linear equations of thermoanemometry

Use of thermoanemometry for the investigation of turbulent flows often leads to systems of linear equations that are difficult to solve. A numerical method of solution, in which measurement errors are taken into account approximately, is proposed for the investigation of solvability of such systems of equations.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 30, No. 5, pp. 811–820, May, 1976.