Current ISI and monitoring technologies in European energy industries

This paper reviews available information on the state of practice of inservice material property monitoring performed in European energy industries. Current practice includes a range of standard nondestructive testing and monitoring methods, improved remote sampling and surveillance specimen testing, and new monitoring techniques which are emerging from ongoing development programs. These new technologies include ultrasonic, positron annihilation, neutron diffraction, and magnetic techniques.     

Projection status of calbindin- and parvalbumin-immunoreactive neurons in the superficial layers of the rat's superior colliculus

Immunocytochemistry and retrograde labeling were used to define the thalamic projections of calbindin- and parvalbumin-containing cells in superficial layers of the rat's superior colliculus (SC). Quantitative analysis revealed that 90.8 +/- 2.2% (mean +/- standard deviation) of the calbindin-immunoreactive neurons in the stratum griseum superficiale (SGS) projected to the dorsal lateral geniculate nucleus (LGNd) and that 91.3 +/- 4.3% of calbindin-immunoreactive neurons in the stratum opticum (SO) projected to the lateral posterior nucleus (LP). In contrast, only 17.3 +/- 2.5% of parvalbumin-immunoreactive neurons in the SGS were found to project to the LGNd and 16.5 +/- 3.1% of the parvalbumin-immunoreactive SO cells were retrogradely labeled after LP injections. Few of the parvalbumin-immunoreactive neurons in either the SGS (7.2 +/- 2.5%) or the SO (9.2 +/- 2.5%) were GABA positive. The retrograde-labeling results suggest that parvalbumin-immunoreactive neurons in the rat's SO and SGS may either be primarily interneurons or have descending projections, while calbindin-containing cells are primarily thalamic projection neurons. These results are consistent with data from other rodents, but almost exactly the opposite of data that have been reported for the cat for these same populations of SC projection neurons. Such interspecies differences raise questions regarding the functional importance of expressing one calcium-binding protein versus another in a specific neuronal population.     

Age of onset of drug use and its association with DSM-IV drug abuse and dependence: results from the National Longitudinal Alcohol Epidemiologic Survey

Although adaptive explanations for menstruation go back at least twenty-five hundred years, in the last decade two new hypotheses have been advanced. The first suggests that menstruation evolved to cleanse the uterus of pathogens introduced by sperm, and the second argues that the function of endometrial regression (with the associated menstruation in humans) is to save energy by getting rid of tissue, rather than maintaining it in the absence of an available blastocyst. Both these suggestions may be questioned on the grounds that they do not take into account the physiology of the reproductive processes involved. Menstruation is not an independent physiological process and is unlikely to have been selected for independently of the evolutionary events that led to it. Furthermore, most primitive menstruating animals would have menstruated infrequently, and many may have reproduced or died without ever menstruating. In order to provide a context for understanding how menstruation may have come about, the evolution of the female vertebrate reproductive tract is briefly reviewed. In later stages, the coevolution of the embryo and uterus resulted in an intimate association between the trophoblast and the uterine blood vessels. As the embryo became more invasive, the uterus responded with increased cellular growth and differentiation of the endometrium to accommodate it. This reached its peak in mammals (such as rodents and humans), where the embryo passes through the epithelium into the endometrial stroma, which responds with differentiation of cells and blood vessels. Progesterone, secreted after ovulation, plays a crucial role in preparation for pregnancy. In addition to its well-known effects on the uterus, progesterone may be important in suppressing the inflammatory reaction that would be expected in response to the presence of a foreign body, such as an embryo. It is also suggested that vascular and cellular differentiation of the endometrial stroma has evolved by adaptation of the inflammatory (granulation tissue) reaction. When progesterone levels fall at the end of the cycle, there is tissue breakdown and bleeding. The uterus then reforms for the next ovulatory cycle. It is shown that the female reproductive tract has multiple functions that must occur in sequence. The coevolution of the embryo and maternal tract thus led to the close contact of two genetically different tissues, and problems such as the inflammatory reaction had to be overcome. Menstruation is a necessary consequence of these evolutionary changes, and needed no adaptive value in order to evolve.     

The xenoestrogen bisphenol A induces growth, differentiation, and c-fos gene expression in the female reproductive tract

The xenoestrogen bisphenol A (BPA) has been shown to mimic estrogen both in vivo and in vitro. BPA stimulates PRL secretion and the expression of a PRL regulating factor from the posterior pituitary in the estrogen-sensitive Fischer 344 rat (F344), but not in Sprague-Dawley (SD) rats. The goal of the present studies was to examine the in vivo actions of BPA on the reproductive tract. The specific objectives were 1) to characterize the short term effects of BPA on cell proliferation and c-fos expression in the uterus and vagina, and 2) to compare the effects of prolonged exposure to low doses of BPA on the reproductive tract of F344 and SD rats. Treatment with single high doses of BPA induced cell proliferation in the uterus and vagina of ovariectomized F344 rats, as determined by bromodeoxyuridine immunostaining. This proliferation was dose dependent (from 37.5-150 mg/kg) and followed a time course similar to that of estradiol (E2). Quantitative RT-PCR revealed that both BPA and E2 increased c-fos messenger RNA levels in the uterus 14- to 16-fold within 2 h, which returned to basal levels after 6 h. In the vagina, BPA-induced c-fos expression remained elevated for up to 6 h, compared with the transient increase caused by E2. Treatment of F344 rats for 3 days with continuous release capsules that supplied a much lower dose of BPA (approximately 0.3 mg/kg x day) resulted in hypertrophy, hyperplasia, and mucus secretion in the uterus and hyperplasia and cornification of the vaginal epithelium. The reproductive tract of SD rats did not respond to this treatment paradigm with BPA. These studies demonstrate that 1) the molecular and morphological alterations induced by BPA in the uterus and vagina are nearly identical to those induced by estradiol; 2) the vagina appears to be especially sensitive to the estrogenic actions of BPA; 3) the reproductive tract of the inbred F344 rat appears more sensitive to BPA than that of the outbred SD rat; and 4) continuous exposure to microgram levels of BPA is sufficient for exerting estrogenic actions.     

Unilateral total lobectomy: is it sufficient surgical treatment for patients with AMES low-risk papillary thyroid carcinoma?

BACKGROUND: Controversy continues regarding the optimal extent of primary thyroid resection in most patients with papillary thyroid carcinoma (PTC), who are at minimal risk of cause-specific mortality (CSM). This study was designed to compare CSM and recurrence rates after either unilateral lobectomy (UL) or bilateral lobar resection (BLR) in patients with PTC considered low risk by AMES criteria. METHODS: Outcome was studied in 1685 patients initially treated during 1940 through 1991 and followed for up to 54 postoperative years (mean, 18 years). One thousand six hundred fifty-six patients (98%) had complete primary tumor resection; 634 (38%) had involvement of regional nodes. One hundred ninety-five patients (12%) had UL; BLR accounted for 1468 (near-total 60%; total thyroidectomy 18%). RESULTS: Thirty-year rates for CSM and distant metastasis were 2% and 3%, respectively. Twenty-year rates for local recurrence and nodal metastasis were 4% and 8%, respectively. There were no significant differences in CSM or distant metastasis rates between UL and BLR (P > .2). After UL, 20-year rates for local recurrence and nodal metastasis were 14% and 19%, significantly higher (P = .0001) than the 2% and 6% rates seen after BLR. CONCLUSIONS: UL was not associated with higher CSM rates, but it was associated with a significantly higher risk of locoregional recurrence. Thus BLR probably represents a preferable initial surgical approach to patients with low-risk PTC.     

Mathematical and Scientific Foundations for an Integrative Engineering Curriculum

All fields of engineering, whether chemical, civil, electrical, materials, mechanical, etc., encompass a common body of essential mathematics and science. In the freshman year of Drexels E⁴ program, this common mathematical and scientific foundation is cultivated in the Mathematical and Scientific Foundations of Engineering I, II and III (MSFE I, MSFE II, MSFE III). In an integrated fashion, MSFE I presents the essential calculus, physics and engineering mechanics vital to the freshman engineering student. In the first two quarters, MSFE II presents chemistry with clearly defined engineering applications and significance: in the third quarter, MSFE II presents living systems with the same thrust. Also in the third quarter, MSFE III presents basic circuits and circuit elements, and a brief introduction to electromagnetic theory.     

Effect of exercise on the plasma nonesterified fatty acid composition of dogs and goats: Species with different aerobic capacities and diets

The goals of this study were to determine: (i) whether mammals mobilize particular nonesterified fatty acids (NEFA) preferentially during locomotion, (ii) if differences in aerobic capacity or diet can affect the pattern of NEFA mobilization and (iii) which individual NEFA are most representative of total NEFA concentration changes, to use them as tracers for turnover studies. Individual NEFA were measured in trained dogs and goats (VO₂max dog/VO₂max goat=2.2; where VO₂max=max-imal oxygen consumption) during treadmill exercise at 40 and 60% VO₂max. Important interspecies differences in individual NEFA concentrations could be attributed to differences in aerobic capacity. The more aerobic species (dog) had much higher plasma NEFA concentrations for all but one NEFA (18∶0), when compared with the low-aerobic species (goat). In addition, exercise caused a large increase in concentration of individual NEFA in the dogs, with the largest increases seen in 18∶1 (150% above resting values) and 16∶0 (60% increase), but it had no effect in goats. Therefore, the aerobic species has a much higher ability for mobilizing and transporting NEFA in plasma than its low-aerobic counterpart. Two NEFA accounted for more than half total plasma NEFA in both species, 18∶1 (about 35% total NEFA) and 16∶0 (20%). Calculation of variability in percent composition reveals that oleate and palmitate also closely reflect changes in total NEFA and are therefore the most appropriate tracers forin vivo kinetic studies in exercising mammals. Differences in diet and digestion physiology explained some differences in the plasma NEFA composition of the two species; this was reflected in the percent contributions of individual fatty acids to total NEFA: in dogs 18∶1>16∶0>18∶2>18∶0, while in goats 18∶1>16∶0>18∶0>18∶2. Also, only goats had 18∶3 (6% total NEFA), a fatty acid of plant origin, while only dogs had 16∶1 (7% total NEFA). Overall, however, the plasma NEFA composition of goats did not exactly reflect that of their diet due to preabsorptive modification of unsaturated fatty acids, while in dogs there was a good correlation between dietary and plasma NEFA.     

Induction of forward mutations at the thymidine kinase locus of mouse lymphoma cells: evidence for electrophilic and non-electrophilic mechanisms

A database of 209 chemicals tested for induction of forward mutations at the heterozygous thymidine kinase (TK +/-) locus in L5178Y mouse lymphoma cells was analyzed for structure-activity relationships using the MultiCASE expert system. Consistent with evidence of several contributing biological mechanisms, these studies suggest that such mutations may occur by more than one mechanism. As might be expected, there was evidence for a component involving direct electrophilic attack on the cellular DNA, in a manner previously established as causative in the induction of mutations in Salmonella. In addition, however, there was also strong evidence for another mechanism or mechanisms involving chromosome missegregation, cellular toxicity or an alternate site of action, such as the microtubules.