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A monitoring system using the collection technique of electrostatic precipitation on to a piezoelectric sensing element is examined. The transduction mechanism is the change in the resonant frequency of the sensing element from its unloaded nominal value of 9 MHz caused by the collected dust. The monitor had the three main design areas (point-to-plane distance, precipitator voltage and electrode-to-dust-inlet distance) optimized at a flow rate of approximately . This led to collection efficiencies greater than 97% with crystal mass sensitivity constants in the range for the aerosol Arizona Road Dust. The total sampling time is limited by overloading of the sensing element by dust. A method of extending the sampling time by using compressed air to clean the sensing element is described.

Testis torsion-induced aspermatogenesis is not necessarily due to permanent loss of blood flow nor to dysfunctional Leydig cells or Sertoli cells. This investigation was undertaken to gain further insight into the mechanism underlying torsion-induced germ cell loss. Male rats were subjected to 1-h or 2-h ischemia-inducing torsion, and testes were examined at either 1, 2, 4, 24, or 48 h after torsion, depending on the study. Testes were examined for evidence of 1) in situ apoptosis by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick-end labeling (TUNEL) technique, 2) apoptosis by the DNA "laddering" technique, 3) leukocyte margination and diapedesis in testicular vessels by immunocytochemical and histological techniques, and 4) testicular lipid peroxidation by the thiobarbituric acid reactive substances assay. The first TUNEL evidence for torsion-induced apoptosis was at 4 h after repair of 1-h torsion. Induction of apoptosis was confirmed by the electrophoretic laddering of DNA fragments. It was hypothesized that apoptosis was induced by reactive oxygen species arising from reperfusing leukocytes. A significant increase in both leukocyte margination and diapedesis occurred 4 h after torsion repair as did a significant increase in intratesticular lipid peroxidation products. These events were contemporaneous with the first appearance of apoptosis and consistent with the hypothesis that post-torsion, germ cell-specific apoptosis is induced by reactive oxygen species.

The 11,424 cases of Lyme disease reported in 1994 represented a nearly 40% increase from the previous year. The dramatic increase of Lyme disease in the United States points to the need for home healthcare nurses to review their knowledge of the clinical manifestations, treatment, and prevention measures for this emerging infection.

Qualitative urinary screening procedures were converted to quantitative methods for urinary cystine and homocystine based on the reactions between these amino acids and cyanide-nitroprusside reagents. Cystine and homocystine are quantified by the measurement of absorbances at 521 and 524 nm, respectively. Cyanide-nitroprusside reacts with both cystine and homocystine. However, in the presence of silver nitrate, only homocystine reacts to produce a magenta color. Following the cyanide-nitroprusside reaction, absorbance must be read within three minutes for cystine and immediately for homocystine. The stability of the absorption spectra has no apparent effect on these quantitative assays. Amino acid concentrations are expressed as ratios to creatinine, which tends to eliminate false negative results in dilute urine specimens. The normal urine value for cystine and homocystine combined is 66.8 +/- 52 (n = 50) mg per g creatinine. The normal value for homocystine alone is 29.9 +/- 16.8 (n = 24) mg per g creatinine. The simplicity of these procedures allows these quantitative methods to be used as screening tests for cystinuria and homocystinuria.

Stress-corrosion behavior of Type 304 stainless steel, Incoloy 800, Inconel 600, and Inconel 690 has been measured in both 10 and 50 percent NaOH environments. Both U-bend and C-ring samples were utilized, and test temperatures were in the range of 600 to 630/sup 0/F. Differences in behavior between the two specimen configurations are attributed primarily to differences in stress level and distribution between the two types of specimens. Stress dependency of cracking of Inconel 600 and Incoloy 800 obtained on pressurized tubing samples was also measured. The total data indicate marked superiority of Inconel 600 at high stresses and high caustic concentrations. The C-ring samples of commercially prepared tubing were also exposed at 110 percent of the room temperature yield strength to strong (50 percent) mixtures of potassium and sodium hydroxides with and without admixtures of typical sludge species for prolonged periods. The general resistance to caustic cracking increased with the nickel content of the alloy; Type 304 stainless steel was the least resistant in all cases. Inconel Alloy 600 and the high-chromium-modification Inconel Alloy 690 were superior, with Incoloy 800 showing intermediate behavior. In uncontaminated caustic, only the stainless steels and Incoloy cracked in a three-month exposure, and amore » six-month exposure was required to produce attack in the Inconel 600. The additions of silica or silica-containing mixtures promoted attack. Low-level additions of halides or lead oxide did not enhance the caustic cracking.« less

Stress corrosion cracking (SCC) tests have been conducted on the age-hardenable NiFeCr Alloys X-750, 718, and A-286 in flowing pressurized water reactor (PWR) primary coolant water at 360 C. The effect of Zr additions to Alloy X-750 and the effect of heat treatment on all of the alloys were studied. The test specimens were U-bends and precracked 1/2 T-CT fracture mechanics specimens. The total exposure was 6000 h, with inspections at 500, 1500, and 3000 h. No initiation was observed on the U-bend specimens, but crack growth was observed on all of the precracked samples. The cracking was intergranular on all of the specimens, with only a few grains of transgranular cracking occurring on one. Zr additions to Alloy X-750 had no significant effect on SCC growth. The 1107 C solution anneal plus the overaged conditions provided the greatest resistance to SCC growth. Alloy 718 exhibited the least resistance.

Stress corrosion tests have been conducted on martensitic, ferritic, and austenitic steels and nickel-base alloys. The tests were conducted on stressed U-bend specimens cut from sheet and tubing and on C-ring specimens cut from tubing. The deoxygenated environments were 10% NaOH at 600 and 630 F (316 and 332 C) and 50% NaOH at 600 F (316 C). The effects of temper embrittlement and sensitization on applicable alloys were studied. It was found that U-bend specimens cracked more readily than C-ring specimens, and that the choice of specimen can affect the relative ranking of some alloys. Temper embrittlement was found to be deleterious to the ferritic alloys, and sensitization was not found to be damaging to the austenitic alloys. The results are discussed with reference to stress, alloy composition, and structure.

Insulin-like growth factors I and II (IGF-I and II) and insulin are chemotactic agents for the human melanoma cell line A2058. As shown in this report, the motility receptor mediating this response is the heterodimeric type I IGF receptor. These three factors are able to compete with 125I-labeled IGF-I for binding to the cell surface with IC50 values equal to approximately 2 (IGF-I), approximately 150 (IGF-II), and approximately 300 nM (insulin). Cross-linking of 125I-IGF-I to the cell surface with disuccinimidyl suberate followed by analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography reveals a 130-kDa protein (reduced) consistent with the alpha component of a type I receptor and a 38-kDa protein which does not bind insulin, and thus could be another IGF-I cell surface binding protein. The anti-IGF-I receptor monoclonal antibody (alpha IR-3) also competes with labeled IGF-I in binding experiments. In contrast, a control monoclonal antibody, matched to alpha IR-3 with respect to IgG subclass, has no significant effect on IGF-I binding. While alpha IR-3 inhibits the motility induced by IGF-I, IGF-II, and insulin, pertussis toxin (0.01-1.0 micrograms/ml) has no significant effect on the motility induced by the insulin-like growth factors or insulin on this cell line. Therefore, the type I IGF receptor appears to mediate a highly potent pertussis toxin-insensitive motility response to IGF-I, IGF-II, and insulin. In contrast, motility induced by the autocrine motility factor, a cytokine produced by the A2058 cells, is not affected by alpha IR-3 but is extremely sensitive to pertussis toxin. When mixtures of autocrine motility factor and IGF-I are employed to induce chemotaxis, the resulting motility is greater than that induced by either agent alone. These data indicate that motility in this melanoma cell line can be initiated through multiple receptors that stimulate the cells by separate transduction pathways. This capability to respond to multiple stimuli could enhance the metastatic potential.

We evaluated and compared Abbott Laboratories' newly developed enzyme immunoassay (EIA) for measuring progesterone receptors (PgR) with that of DuPont's steroid-binding assay (SBA). We also used both methods to study the stability of PgR under various conditions. THere were excellent correlations for all 59 cytosols compared (r = 0.94) and for the 44 cytosols containing PgR greater than 10 fmol per milligram of protein (r = 0.93), but the correlation for cytosols containing less than 10 fmol of PgR per milligram was poor. We found PgR to be more stable as assayed by EIA than by SBA. The biological half-lives of PgR at 30, 4, and -60 degrees C were approximately 3 h, 6 days, and 19 days, respectively. The effect of molybdate on PgR is complex. Its presence during tissue homogenization leads to analytical recovery of more PgR and may stabilize PgR during storage. Its presence during enzyme immunoassay is less critical. Unlike estrogen receptor, PgR is not protected by its ligand, R5020.

Multi-element overlay coatings applied by electron beam vapor deposition to gas turbine superalloys have been the subject of intensive research and development programs for the past eight years. Such coatings have proven to be superior to diffusion coatings in a number of critical applications primarily because of the ease with which compositional variations can be effected to meet unique protection and mechanical requirements. Overlay coating structural features have been identified (i.e., open columnar structure, vapor source spit marks, flakes and pits), along with present and future methods for their control. Laboratory observations have indicated that in a line-of-sight process, the open columnar structure is the result primarily of shadowing effects and the limited surface diffusion of the depositing atoms. Point defects (spits, flakes, and pits) result from pool behavior and substrate contamination. Methods of minimizing these defects range from in-process controls to post-coating processing. Current development areas for improved processing techniques such as gas randomization and ion plating should result in further improvements and elimination of some present post-coating processing requirements.

Stress corrosion cracking (SCC) studies have been conducted on martensitic, ferritic, duplex, and austenitic stainless steels in environments associated with fault conditions in steam supply systems. The environments were aqueous solutions at 316 to 332 C (600 to 630 F) containing additions of Pb, Hg, NaOH, NaCl + O2 or PO43−. The specimens were C-rings cut from tubing. The stainless steels were AISI Type 405, AISI Type 410, 18Cr-2Mo-Ti stabilized, a low interstitial 26Cr-1Mo, Sandvik 3RE60, and AISI Type 304. The as-received mill annealed structures were generally the most resistant to SCC. Heat treatment markedly affected the susceptibility of the alloys to cracking with embrittled structures being the most susceptible to cracking. The results are presented as tables and as photomicrographs of the exposed samples.

Sensitization processes in two high Ni-Cr-Fe alloys are studied with the Huey and accelerated Strauss tests, magnetic permeability measurements and scanning electron microscopy. There is good agreement between the corrosion tests for Incoloy* Alloy 800 but not for Inconel* Alloy 600. High Huey corrosion rates are associated with large magnetic permeabilities which result from chromium depletion near the grain boundaries. The relative contribution of the chromium depleted region and of electrochemical effects to the Huey corrosion rate could not be determined because the formation and disappearance of the chromium depleted zone and of the continuous grain boundary carbides occur concurrently.

We evaluated and compared Abbott Laboratories' newly developed enzyme immunoassay (EIA) for measuring progesterone receptors (PgR) with that of DuPont's steroid-binding assay (SBA). We also used both methods to study the stability of PgR under various conditions. THere were excellent correlations for all 59 cytosols compared (r = 0.94) and for the 44 cytosols containing PgR greater than 10 fmol per milligram of protein (r = 0.93), but the correlation for cytosols containing less than 10 fmol of PgR per milligram was poor. We found PgR to be more stable as assayed by EIA than by SBA. The biological half-lives of PgR at 30, 4, and -60 degrees C were approximately 3 h, 6 days, and 19 days, respectively. The effect of molybdate on PgR is complex. Its presence during tissue homogenization leads to analytical recovery of more PgR and may stabilize PgR during storage. Its presence during enzyme immunoassay is less critical. Unlike estrogen receptor, PgR is not protected by its ligand, R5020.

Insulin-like growth factors I and II (IGF-I and II) and insulin are chemotactic agents for the human melanoma cell line A2058. As shown in this report, the motility receptor mediating this response is the heterodimeric type I IGF receptor. These three factors are able to compete with 125I-labeled IGF-I for binding to the cell surface with IC50 values equal to approximately 2 (IGF-I), approximately 150 (IGF-II), and approximately 300 nM (insulin). Cross-linking of 125I-IGF-I to the cell surface with disuccinimidyl suberate followed by analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography reveals a 130-kDa protein (reduced) consistent with the alpha component of a type I receptor and a 38-kDa protein which does not bind insulin, and thus could be another IGF-I cell surface binding protein. The anti-IGF-I receptor monoclonal antibody (alpha IR-3) also competes with labeled IGF-I in binding experiments. In contrast, a control monoclonal antibody, matched to alpha IR-3 with respect to IgG subclass, has no significant effect on IGF-I binding. While alpha IR-3 inhibits the motility induced by IGF-I, IGF-II, and insulin, pertussis toxin (0.01-1.0 micrograms/ml) has no significant effect on the motility induced by the insulin-like growth factors or insulin on this cell line. Therefore, the type I IGF receptor appears to mediate a highly potent pertussis toxin-insensitive motility response to IGF-I, IGF-II, and insulin. In contrast, motility induced by the autocrine motility factor, a cytokine produced by the A2058 cells, is not affected by alpha IR-3 but is extremely sensitive to pertussis toxin. When mixtures of autocrine motility factor and IGF-I are employed to induce chemotaxis, the resulting motility is greater than that induced by either agent alone. These data indicate that motility in this melanoma cell line can be initiated through multiple receptors that stimulate the cells by separate transduction pathways. This capability to respond to multiple stimuli could enhance the metastatic potential.