ALBERT

Notes: Abstract Supercritical fluid extraction (SFE) is a technique for sample preparation that is quickly replacing Soxhlet extraction and ultrasonic extraction. This manuscript introduces two real-world applications of SFE that serve as the basis of undergraduate laboratory experiments: the analysis of caffeine in ground coffee and nicotine in cigarette tobacco. The extracts are analyzed with gas chromatography-mass spectrometry (GC-MS). The experiments are presented in a discovery fashion that enables students to develop a theoretical understanding of the role of intermolecular forces in the extraction process. The focus on theoretical aspects of SFE makes these experiments appropriate for analytical and physical chemistry labs.

Notes: We have tested a McDonnell Douglas short milticusp plasma generator, designed to generate a positive hydrogen ion beam which is enriched with H2+ ions. Initial testing shows that the prototype source is capable of producing a positive hydrogen ion beam with H2+ percentage greater than 85%. The total ion-current density was 56 mA/cm2. For a higher current density of 110 mA/cm2, the percentage of H2+ ions is approximately 73% as measured by a magnetic deflection spectrometer. A comparison between tungsten and lanthanum hexaboride cathodes shows that tungsten filaments can provide better performance.

Notes: Abstract Monte Carlo simulations of fatigue in welded joints have been performed using an approach which combines a model for initiation with a multiple surface crack propagation model. The results have been compared with experiments on T-plate welded joints in which initiation and propagation of surface cracks were monitored using potential drop techniques. Predictions of initiation life using a local strain approach were conservative. Despite this underprediction of initiation life, predictions of total fatigue life were very good as a consequence of accurate simulations of propagation life and the fact that initiation represented on average only 12 to 22% of total life, depending on stress level. The initiation model considered variability due to the local weld toe angle and radius, and material strain–life behaviour. The only variability considered in the propagation analysis was the position and timing of initiation events, which leads to variability in coalescence. The underprediction of the variability in propagation and total lives was attributed to the underprediction of initiation life and the fact that out-of-plane coalescence effects were ignored.

Notes: Abstract Cerium can be determined spectrofluorimetrically (λem 350 nm, λex 260 nm) based on the relatively intense native fluorescence of the cerium(III) aquo-ion. The main potential interference in the analysis of steel from iron(III), cerium(IV) and chromium(VI) are removed by use of a carrier solution containing 2.5% w/v hydroxylammonium chloride. The slight residual interference from iron(II) can be corrected by a matrix matching factor linearly related to the amount of iron present. The calibration graphs are linear over the range 0–7 μg ml−1 based on 250 μl injection volumes. The sampling rate was 30 h−1. The relative standard deviation was 2.0% (n=5) at 3 μg ml−1 cerium. The system has been applied to the determination of cerium in carbon or low alloy steels.

Notes: Abstract. In previous studies we found that the calciotropic hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] augments the action of either prostaglandin E1 (PGE1) or NaF to induce differentiation of human promyelocytic HL-60 cells, a process that features increased generation of nitric oxide (NO) via up-regulation of inducible nitric oxide synthase (iNOS). We have now examined the short-term interaction of 1,25(OH)2D3 with phorbol 12-myristate 13-acetate (PMA) and dimethylsulfoxide (DMSO) in these cells. PMA (100 nM) alone generally up-regulated several classical indices of macrophagic differentiation and stimulated cellular production of interleukin (IL)-1α, IL-6, tumor-necrosis factor (TNF)-α, PGE2, and NO. Increased generation of NO primarily resulted from increased expression of cellular iNOS. When 1,25(OH)2D3 (10 nM) was added to PMA treatments, most PMA-induced changes, particularly its effects to up-regulate iNOS-dependent NO production and change cell morphology, were multiplicatively augmented. In contrast, DMSO (1.3%) alone, an inducer of granulocytic differentiation, increased cytokine production, but failed to stimulate NO production or induce iNOS. In contrast to its striking interaction with PMA, 1,25(OH)2D3 could not augment DMSO's differentiative effects. Changes in cellular cytokine production were eliminated as the driving force in HL-60 differentiation when specific neutralizing antibodies failed to produce any attenuation of iNOS up-regulation or of the shifts in cell morphology. However, indomethacin (30 μM) blocked the synergistic interaction between 1,25(OH)2D3+ PMA to shift cell morphology and stimulate NO production. Subsequently adding PGE2 (1 ng/ml) to indomethacin-treated cells restored the ability of 1,25(OH)2D3+ PMA to interactively increase cellular NO production, but failed to fully replicate the strong shift in cell morphology typical of PMA + 1,25(OH)2D3 treatments. Our findings suggest that interaction between 1,25(OH)2D3 and PMA to induce macrophagic differentiation increases iNOS-dependent NO production by a mechanism involving a cyclooxygenase product(s), possibly PGE2.

Notes: Abstract Human promyelocytic HL-60 cells can be induced by biochemical agents to differentiate in vitro towards divergent types of myelomonocytic cells. It has been reported that prostaglandin E1 (PGE1) can induce granulocytic differentiation and that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) can induce monocytic differentiation. We have now examined the effects of these compounds, both alone and in combination, on HL-60 cell differentiation. PGE1 (1 μg/ml) or 1,25(OH)2D3 (10 nM) each inhibited cell proliferation over 48–96 hours of treatment, but combined treatment with both agents was necessary to produce a strong inhibition. The percentage of HL-60 cells that can reduce nitroblue tetrazolium (NBT) (a characteristic index of early monocytic or granulocytic differentiation) increased 13-fold within 72 hours of PGE1 treatment, and 1,25(OH)2D3 produced a fivefold stimulation. However, combined treatment (PGE1 plus 1,25(OH)2D3) produced a dramatic 35-fold increase. HL-60 cells did not produce significant levels of nitric oxide (NO) before 48 hours in culture, and treatment with PGE1 or 1,25(OH)2D3 did not significantly increase cellular NO elaboration over control levels. However, combined treatment produced a striking 12-fold increase over control levels. Similarly, combined treatment was necessary to obtain the maximal time-dependent stimulation of cellular lactate dehydrogenase (LDH) activity (a marker of granulocytic differentiation) as well as acid phosphatase (ACP) activity. During this same period of time, PGE1, but not 1,25(OH)2D3, markedly stimulated cellular claboration of interleukin (IL)-1α, IL-6, and tumor necrosis factor (TNF)-α, and 1,25(OH)2D3 cotreatment strongly augmented these effects. Thus, combined treatment with 1,25(OH)2D3 plus PGE1 generally augmented the apparent conversion of these cells, producing synergistic (multiplicative) or additive effects. Furthermore, PGE1 induced within 48 hours the more general phenotypic changes classically associated with the differentiation of these cells: increased expression of chloroacetate esterase (ChAE) (a granulocytic marker), decreases in the nuclear/cytoplasmic ratio (characteristic of development beyond the promyelocyte/myelocyte stage), and major alterations in morphology from floating spherical cells to loosely adherent, elliptical polygons. 1,25(OH)2D3 had little effect itself on most of these parameters, but augmented the morphological changes induced by PGE1 treatment. Within 48 hours, the ability of these cells to reduce the tetrazolium salt WST-1, a general measure of cellular metabolic activity, was increased by PGE1, but not by 1,25(OH)2D3; however, the combination of 1,25(OH)2D3 and PGE1 again produced the strongest stimulation. Similarly, only PGE1 significantly reduced intracellular ATP levels, but combined treatments produced a more pronounced decrease. In summary, our findings suggest that PGE1, not 1,25(OH)2D3, is sufficient to promote rapid in vitro differentiation of HL-60 cells along the granulocytic pathway; however, the PGE1-induced conversion of these cells is markedly augmented by cotreatment with 1,25(OH)2D3. In addition, these converted HL-60 cells preferentially utilize the glycolytic pathway, rather than the citric acid cycle, for production of ATP, a metabolic characteristic that resembles that described for mature granulocytes.

Notes: Abstract Schönbein’s correspondence with Berzelius (1836–1847) and with Faraday (1836–1862) are shown to be excellent accessible sources for his changing views as to the nature of ozone. Two of Schönbein’s qualitative tests for ozone, namely the reaction with neutral potassium iodide solution and that with indigo have current quantitative application. Andrew’s quantitative studies of the ozone reaction with potassium iodide (1856) and his work with Tait on the volumetric gas phase decomposition of ozone (1860) confirmed the allotropic nature of ozone but did not yield the structure which was first proposed by Odling (1861). Modern spectroscopic studies owe their origin to Hartley’s studies of 1881.

Notes: Abstract In recent experiments we demonstrated the feasibility of using the oxygen dependence of luminescent molecules for surface pressure measurement in aerodynamic testing. This technique is based on the observation that for many luminescent molecules the light emitted increases as the oxygen partial pressure, and thus the air pressure, the molecules see decreases. In practice the surface to be observed is coated with an oxygen permeable polymer containing a luminescent molecule and illuminated with ultraviolet radiation. The airflow induced surface pressure field is seen as a luminescence intensity distribution which can be measured using quantitative video techniques. Computer processing converts the video data into a map of the surface pressure field. The experiments consisted of evaluating a trial luminescent coating in measuring the static surface pressure field over a two-dimensional NACA-0012 section model airfoil for Mach numbers ranging from 0.3 and 0.66. Comparison of the luminescent coating derived pressures were made to those obtained from conventional pressure taps. The method along with the experiment and its results will be described.