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At least 451 records · Page 25Linked to original sources
PubMed1998

Fine particulate organic material in the Los Angeles Basin-I: assessment of the high-volume Brigham Young University organic sampling system, BIG BOSS

A multi-system, high-volume, parallel plate diffusion denuder Brigham Young University Organic Sampling System (BIG BOSS) was tested using collocated samplers at the Pico Rivera Monitoring Station of the South Coast Air Quality Management District, South Coast Air Basin, in September 1994. Six-hr daytime and 9-hr nighttime samples were collected with a flow of about 200 L/min through each of the three systems designed to collect particles smaller than 2.5, 0.8, and 0.4 microns in a diffusion denuder sampler. Efficiency for the removal of gas phase organic compounds by the diffusion denuder was evaluated using both theoretical predictions and field measurements. Both measured and calculated data indicate high denuder efficiency for the removal of gas phase aromatic and paraffinic compounds. The precision of the BIG BOSS was evaluated using collocated samplers. The precision of determination of total carbon and elemental carbon retained by a quartz filter or of semi-volatile carbonaceous material lost from particles during sampling averaged +/- 7%. The precision of determination of individual organic compounds averaged +/- 10%. An average of 42 and 62% of the particulate organic material was semi-volatile organic compounds (SVOCs) lost from particles during sampling for daytime and nighttime samples, respectively. This "negative" sampling artifact was an order of magnitude larger than the "positive" quartz filter artifact due to adsorption of gas phase organic material. Daytime concentrations of fine particulate elemental carbon and nonvolatile organic carbon were higher than nighttime concentrations, but nighttime fine particles contained more semi-volatile organic material than daytime.

Journal Article↗
PubMed1993

[Pathogenesis of micropolygyria].

Neonatal micropolygyria (MG) was studied concerning a possible proportion of neuroblastic migration in its formal pathogenesis. Section of three selected groups of neonatal brains yielded complete series of frontal histotopograms. Findings were compared with experimental MG induced in the period of neuroblastic migration. Group A: Registration of residual neuroblastic migration in cerebral cortex. There was found that the residual migration could participate on production of MG as late as in the 27th week of gravidity (weight of 1000g). Group B: Evaluation of neuroblastic migration in partial necrosis. Migrating neuroblasts were found in neonatal cerebral cortex with hypoxic encephalopathy. A correlation existed with experimental data proving that MG neonatal cerebral cortex could be produced by neuroblastic migration through fields of partial necrosis. Group C: Detailed investigation concerned 4 neonates with MG due to hypoxic necroses- 2 cases with probable lesion of big vessels perfusion after thromboembolia and 2 cases with cortical vessels perfusion lesion in toxoplasmosis and rubella meningoencephalitis. Findings were compared with experimental MG and correlated with the data from group A and B. Results showed that the production of MG formations in neonatal brain (atypical irregular MG cortex, 4-layer-MG cortex, intracortical nodules, MG intracortical microsulci, neuronal protrusion into molecular layer and pia mater, intracortical and subcortical neuronal heterotopias) can be participated by neuroblastic migration in the transformation of injured immature cerebral cortex. Probable timing of various MG formations and of a relation of MG to ulegyria were presented.

Brain↗
PubMed2000

Depletion potential in hard-sphere mixtures: theory and applications

We present a versatile density functional approach (DFT) for calculating the depletion potential in general fluid mixtures. For the standard situation of a single big particle immersed in a sea of small particles near a fixed object, the system is regarded as an inhomogeneous binary mixture of big and small particles in the external field of the fixed object, and the limit of vanishing density of the big species, rho(b)-->0, is taken explicitly. In this limit our approach requires only the equilibrium density profile of a one-component fluid of small particles in the field of the fixed object, and a knowledge of the density independent weight functions which characterize the mixture functional. Thus, for a big particle near a planar wall or a cylinder or another fixed big particle, the relevant density profiles are functions of a single variable, which avoids the numerical complications inherent in brute force DFT. We implement our approach for additive hard-sphere mixtures, comparing our results with computer simulations for the depletion potential of a big sphere of radius R(b) in a sea of small spheres of radius R(s) near (i) a planar hard wall, and (ii) another big sphere. In both cases our results are accurate for size ratios s=R(s)/R(b) as small as 0.1, and for packing fractions of the small spheres eta(s) as large as 0.3; these are the most extreme situations for which reliable simulation data are currently available. Our approach satisfies several consistency requirements, and the resulting depletion potentials incorporate the correct damped oscillatory decay at large separations of the big particles or of the big particle and the wall. By investigating the depletion potential for high size asymmetries we assess the regime of validity of the well-known Derjaguin approximation for hard-sphere mixtures and argue that this fails, even for very small size ratios s, for all but the smallest values of eta(s) where the depletion potential reduces to the Asakura-Oosawa potential. We provide an accurate parametrization of the depletion potential in hard-sphere fluids, which should be useful for effective Hamiltonian studies of phase behavior and colloid structure. Our results for the depletion potential in a hard-sphere system, with a size ratio s=0.0755 chosen to mimic a recent experiment on a colloid-colloid mixture, are compared with the experimental data. Although there is good overall agreement, in particular for the dependence of the oscillations on eta(s), there are some significant differences at high values of eta(s).

Journal Article↗
PubMed1992

Survey of computerized obstetric information systems in Austria.

The aim of this study was to evaluate obstetric electronic data processing (EDP) in Austria and to analyse its problems, advantages and acceptance in a single big obstetric department. We sent questionnaires to every obstetric department in the country. The overall response rate was 77% (73 departments). Only 24 (33%) were using computer aided documentation, but these covered 63% of deliveries in Austria. The proportionate times spent on documentation were 57% for physicians and 43% for midwives, with physicians playing a bigger role in larger departments using electronic documentation. Sixty-five percent of physicians and 31% of midwives readily accepted computerization. We also studied an obstetric department with over 3000 births per year. Twenty-five percent of the medical staff did not believe that computerization saved time, although they appreciated its value to administration and for producing printouts. Advantages in completeness (92%) and accuracy (76%) were recognized. After 6 month's use acceptance of EDP documentation improved significantly.

Attitude of Health Personnel↗
PubMed2004

Efficient MILP formulations for the optimal synthesis of chromatographic protein purification processes.

The use of recombinant proteins has increased greatly in recent years, as well as the techniques used for their purification. The selection of an efficient process to purify proteins is a major bottleneck found when trying to scale up results obtained in the laboratory to a large-scale industrial process. One of the main challenges in the synthesis of downstream purification stages in biotechnological processes is the appropriate selection and sequencing of chromatographic steps. The objective of this work is to develop mixed integer linear programming models for the synthesis of protein purification processes. Models for each chromatographic technique rely on physicochemical data of a protein mixture, which contains the desired product and provide information on its potential purification. Formulations that are based on convex hull representations are proposed to calculate the minimum number of steps from a set of chromatographic techniques that must achieve a specified purity level and alternatively to maximize purity for a given number of steps. The proposed models are tested in several examples with experimental data and present time reductions of up to three orders of magnitude when compared to big-M formulations.

Biotechnology↗
PubMed1994

Use of transgenic mouse lacI/Z mutation assays in genetic toxicology.

The Big Blue (lacI) and the Muta Mouse (lacZ/GalE) assays offer a practical means to generate mutation data from a wide range of tissues of treated animals. Our experience with these assays has so far been encouraging, but several fundamental questions require addressing. Chief among these is whether these assays are to be regarded as replacements for standard rodent genotoxicity assays, or if they are to be regarded as assays for the prediction of potential carcinogenic organotropy using a multiple-dose protocol. The interplay between the independent chemical properties of mitogenesis and DNA adduction require also to be studied. The value and sensitivity of these assays can only be assessed when these questions have been internationally addressed and concluded.

Animals↗
PubMedDate not supplied

The voices of teen mothers: the experience of repeat pregnancy.

PURPOSE: To explore the insights of young mothers with regard to their life aspirations, the changes in their lives as a result of parenting, and their beliefs of the impact of repeat pregnancy on their aspirations and life course. STUDY DESIGN AND METHODS: Ethnographic, descriptive research with a purposive sample of key informants (n = 16), using semistructured interviews to solicit rich qualitative data. Iterative methods, recursive data sifting, and Ethnograph 5.0 were used in data analysis. RESULTS: Young mothers were asked questions about four domains of their lives: (a) their existing life context, including support and background characteristics, (b) their relationships, including family, friends, and intimate others, (c) their vocation, including education, work, and money, and (d) their personal characteristics and parenting. Young mothers' perceptions reflected costs, rewards, and neutral aspects associated with young mothering and repeat pregnancies. The three themes that emerged from the interview data included Looking for or finding a better life, Making a hard life harder, and No big difference in my life. CLINICAL IMPLICATIONS: Nurses may use these results to understand better the young mothers with whom they work, to develop intervention programs, and to support policies that attend to the needs of young mothers. By responding to young mothers' issues and challenges from their perspective, nurses may be more effective in preventing or delaying repeat pregnancy in the teen years.

Adaptation, Psychological↗
PubMed1999

Vascular matrix metalloproteinase-2 cleaves big endothelin-1 yielding a novel vasoconstrictor.

Matrix metalloproteinase-2 (MMP-2, gelatinase A) and its tissue inhibitor (TIMP-2) are mainly known for their roles in the (patho)physiological remodeling of the vasculature, angiogenesis, tissue repair, tumor invasion, inflammation, and atherosclerotic plaque rupture. A mechanism of action of MMP-2 is the proteolytic breakdown of specific extracellular matrix proteins. The amino acid sequences in interstitial collagen (Gly-Leu/Ile) and laminin-5 (Ala-Leu) that are cleaved by MMP-2 are homologous to a region (Gly(32)-Leu(33)) within human big endothelin-1[1 to 38] (big ET-1). Big ET-1 requires cleavage to an active form to produce vasoconstriction. We tested the hypothesis that vascular MMP-2 can cleave big ET-1, thus generating a vasoconstrictor peptide. In perfused rat mesenteric arteries with an intact endothelium, inhibition of vascular MMP-2 with TIMP-2 reduced (by 16.2+/-4.2%) the vasoconstrictor effects of big ET-1 (50 pmol). However, when the endothelium was mechanically removed, TIMP-2 abolished (>90%) the vasoconstriction of big ET-1, and this effect was mimicked by an anti-MMP-2 antibody. Incubation of big ET-1 with recombinant human MMP-2 resulted in the specific cleavage of the Gly(32)-Leu(33) bond of big ET-1. Moreover, the resultant peptide ET-1[1 to 32] exerted greater vasoconstrictor effects than big ET-1. We conclude that vascular MMP-2 contributes to the vasoconstrictor effects of big ET-1 by cleaving big ET-1 to yield a novel and potent vasoconstrictor, ET-1[1 to 32]. These data implicate, for the first time, the endogenous MMP-2/TIMP-2 system in the regulation of vascular reactivity.

Animals↗
PubMed1983

[Serum levels of receptor assayable insulin-like activity in various diseases].

Utilizing an acid gel chromatography and insulin radioreceptor assay (RRA), serum levels of receptor assayable insulin-like activities were measured under various conditions. Acid gel filtration of sera on a Sephadex G-50 was adopted to separate small molecular ILAs from binding proteins before the assay by RRA. By employing 125I-pork insulin as the tracer, and pork insulin as the standard, an RRA for insulin was developed, in which kidneys of sacrificed pregnant guinea pigs were used as the source of the solubilized receptor. After gel-filtration of the sera, pooled fractions, which grossly corresponded to those of 125I-insulin marker, were assayed by RRA. The subjects consisted of fifty-nine cases: normal control subjects (n = 19), active acromegaly (6), Sheehan's syndrome (5), liver cirrhosis (7), chronic renal failure (10), non-insulin dependent diabetes mellitus (6), overt hyperthyroidism (5) and Nelson's syndrome (1). The average receptor assayable ILA of the normal control subjects was 40.2 +/- 12.2 ng/ml. As insulin RRA has a big interassay variation, receptor assayable ILA-ratio was used to minimize the variation, and each data was shown as the ratio to the average ILA of the normal controls. By this method, sera from normal adults had a mean (+/- SD) receptor assayable ILA ratio of 1.00 +/- 0.28. Four out of six cases of acromegaly revealed significantly high concentrations, and the average receptor assayable ILA-ratio of acromegaly was 1.30 +/- 0.28 (mean +/- SD, p less than 0.015). In the cases of Sheehan's syndrome, the ILA-ratio was 0.30 +/- 0.12, which was significantly low (p less than 0.001). Therefore, GH dependency was suspected from these two factors. However, the direct correlation was not indicated between GH and receptor assayable ILA. It was also considered that receptor assayable ILA was influenced not only by GH but also by some other factors. Furthermore, the subjects with liver cirrhosis indicated the low levels of receptor assayable ILA-ratio of 0.46 +/- 0.31, while the subjects with chronic renal failure showed the high ILA-ratio of 1.59 +/- 0.45 (p less than 0.05). No differences in ILA-ratio were found in the subjects with diabetes mellitus, hyperthyroidism and Nelson's syndrome, compared to the normal subjects.

Acromegaly↗
PubMedDate not supplied

Comparison of three arterial pulse waveform classification techniques.

Peripheral pulse waveforms can become stretched and damped with increasing severity of peripheral vascular disease (PVD) and hence could provide valuable diagnostic information. This study compares the diagnostic performance of 3 established classification techniques (a linear discriminant classifier, a k-nearest neighbour classifier, and an artificial neural network) for the detection of lower limb arterial disease from pulse waveforms obtained using photoelectric plethysmography (PPG). Pulse waveforms and pre- and post-exercise Doppler ultrasound ankle to brachial pressure indices (ABPI) were obtained from patients attending a vascular measurement laboratory. A single PPG pulse from each big toe was recorded direct to computer, pre-processed, and then used as classifier input data. The correct classifier outputs were the corresponding ABPI diagnostic classification. Pulse and ABPI measurements from 100 legs were used as training data for each classifier, and the computed classifications for pulses from a further 266 legs were then compared with their ABPI diagnoses. The diagnostic accuracy of the artificial neural network (80%; was higher than for the optimized k-nearest neighbour classifier (k = 27, accuracy 76% and the linear discriminant classifier (71%). The Kappa measure of agreement which excludes chance was highest for the artificial neural network (57%) and significantly higher than that of the linear discriminant classifier (Kappa 40%, p < 0.05). The value of Kappa for the optimized k-nearest neighbour classifier (k = 27) was intermediate at 47%. This study has shown that classifiers can be taught to discriminate between small, and perhaps subtle, differences in features. We have demonstrated that artificial neural networks can be used to classify arterial pulse waveforms, and can perform better overall than k-nearest neighbour or linear discriminant classifiers for this application.

Ankle↗
PubMed2002

Extending the search for folk personality constructs: the dimensionality of the personality-relevant proverb domain.

College students (95 men and 264 women) rated how well 211 familiar proverbs described their behavior and beliefs. A factor analysis of these data yielded 7 major dimensions; many of the factors were similar to recognized lexical personality factors. Big Five Conscientiousness and Neuroticism were each strongly associated with a single proverb dimension (interpreted as Restraint and Enjoys Life, respectively). Big Five Agreeableness, Extraversion, and Intellect/Imagination were all associated with several proverb dimensions. Agreeableness was most strongly associated with proverb dimensions representing Machiavellian behavior and strong Group Ties, and both Extraversion and Intellect showed particularly notable associations with an Achievement Striving dimension. The 2 remaining proverb dimensions, which represented a belief that Life is Fair and an attitude of Cynicism, could not be accounted for by the Big Five.

Aphorisms and Proverbs as Topic↗
PubMed1990

[Health status of goldsmiths of the USSL 71 in Valenza].

The article verifies health's state and style of life of the goldsmith people of the USSL n. 71-Valenza Po. The study, executed in the 1989 year, consisted in the distribution of a autowriting questionnaire to 565 goldsmith who are working for the majority in small factory. Questionnaire's analysis showed the young age of workers and the big experience in specific duty. The diseases of locomotor district are represented with great differences respect data of italian population. These data are plausibility induced with the postural vices during working activity. Other pathologies relevant are contact dermatitis, chronic bronchitis, bronchial asthma and optic disturb. The results of the study had induced the Authors to organize new and over deepened epidemiological studies to investigate disturbs of visus and locomotor district.

Adult↗
PubMedDate not supplied

[Cloning and comparative characteristics of genes coding two structurally distant delta-endotoxins of Bacillus thuringiensis var. galleriae and kurstaki].

Representative total DNA libraries of Bac. thuringiensis var. kurstaki (strain Dipel) and galleriae (strain 11-67) have been constructed on the basis of phasmid vector lambda pSL5. Recombinant phasmid clones, carrying delta-endotoxin-coding genes of both subspecies have been isolated by means of immunoenzyme screening. Restriction mapping and partial nucleotide sequence determination have demonstrated that phasmid lambda pOC2, isolated from var. kurstaki DNA library, contains the complete delta-endotoxin-coding gene, identical to the one, described by Schnepf H.E. et al. J. Biol. Chem. 1985. V. 260. P. 6264. Recombinant phasmids lambda pOC10 and 11 have been shown to contain the full-sized gene, coding delta-endotoxin of Bac. thuringiensis var. galleriae. The protein products of the cloned genes have been characterized by Western-blot analysis and bioassays. The absence of substantial homology of two genes, evidenced by Southern-blot hybridisation, correlates with sufficiently big differences in biological specificity of the corresponding proteins. This is in accordance with our previous data on N-terminal amino acid sequence determination of delta-endotoxins of those subspecies of Bac. thuringiensis.

Bacillus thuringiensis↗
PubMed1983

[Disseminated Kaposi's sarcoma of the skin in a young homosexual with substance abuse].

This is a report on a young homosexual US citizen with disseminated Kaposi's sarcoma of the skin who has lived in Berlin for about 1 year. During the last few years this malignant variant of the conventional Kaposi's sarcoma-characterized by rapid generalization and aggressive course--has become epidemic in some big cities in the USA. Until now there exist only a few reports from Europe. The data of our patient are representative of the typical epidemiologic, anamnestic, clinical, and diagnostic features of this unusual disease. Acquired immunodeficiency, high frequency of infections, and drug abuse may represent major etiologic factors. This report underlines the possibility that the disseminated type of Kaposi's sarcoma in young men may be observed more often in Europe in the near future.

Adult↗
PubMed1981

Alcohol and the pancreas. II. Pancreatic morphology of advanced alcoholic pancreatitis.

The histopathology of advanced chronic alcoholic pancreatitis is dominated by cellular degeneration, atrophy and fibrosis. Sequential changes in the histopathology of alcoholic pancreatic disease has been defined and traced from initial injury to end-stage disease. These sequential histopathologies have been correlated with clinical syndrome and secretory patterns. The data are more consistent with a toxic-metabolic pathogenesis of alcoholic pancreatitis than the previous Big Duct and Small Duct hypotheses.

Adult↗
PubMed1994

[Anesthesia relevant features of laparoscopy--the value of capnometry].

End-expiratory capnometrical and capnographical data correspond well with blood carbon dioxide content. Carbon dioxide insufflation for laparoscopy results in a big increase in CO2 uptake as well as in respiratory deterioration due to positioning and increased intra-abdominal pressure. We observed 226 female patients during laparoscopy under general anaesthesia (midazolam-alfentanil-atracurium or vecuronium) and artificial ventilation. Airway peak and plateau pressure increased by about 75% as compared to pre-insufflation levels. End-tidal carbon dioxide exceeded pre-insufflation levels by 2 to 19 mmHg (mean 9 mmHg). Both findings were correlated to speed and overall volume of CO2 insufflation. Major cardiocirculatory side-effects were not observed, except for rare bradycardia, which responded to atropine. Considerable regurgitation via or beneath the gastric tube occurred in 52%. Thus, general anaesthesia with endotracheal intubation and consistent monitoring, including capnometry, may be regarded as particularly safe as far as aspiration of gastric contents and ventilatory requirements are concerned.

Adult↗
PubMed1996

Frequency and spectrum of ethylnitrosourea-induced mutation at the hprt and lacI loci in splenic lymphocytes of exposed lacI transgenic mice.

The development of mouse models with the endogenous hypoxanthine-guanine phosphoribosyl transferase (hprt) gene and lacI transgene as mutational targets provides an excellent opportunity to compare the mutant frequency (Mf) and types of mutations induced in vivo in different sequence contexts. To this end, a study was conducted to determine the Mfs and spectrum of mutations induced at these loci in splenic T cells from male B6C3F1 Big Blue mice (6 weeks old) exposed to N-ethyl-N-nitrosourea (ENU). Six weeks after i.p. injection of 40 mg ENU/kg, T cells were isolated from control (n = 7) and treated (n = 8) mice for the culture of hprt mutants and for the extraction of DNA and recovery of lacI mutants. Mutations in hprt exon 3 and in lacI were quantified and analyzed using published procedures (S. W. Kohler et al., Proc. Natl. Acad. Sci. USA, 88: 7958-7962, 1991; T. R. Skopek et al., Proc. Natl. Acad. Sci. USA, 89: 7866-7870, 1992). In treated mice, the Mfs (average +/- SE) in hprt (6.0 +/- 0.2 x 10(-5)) and lacI (11.4 +/- 1.8 x 10(-5)) were approximately 16.2-fold (P = 0.006) and 3.4-fold (P = 0.009), respectively, above controls. However, the average induced Mfs (i.e., induced Mf = treatment Mf - background Mf) in hprt and lacI were similar, with the respective increases in Mf being 5.6 +/- 0.2 x 10(-5) and 8.0 +/- 2.3 x 10(-5) over background. Eleven of the 107 hprt mutants from treated Big Blue mice had mutations in exon 3, with 73% being substitutions at AxT bp. These data are similar to those observed in ENU-exposed nontransgenic B6C3F1 mice, in which 62 of 69 exon 3 mutations were substitutions at AxT bp (T. R. Skopek et al., Proc. Natl. Acad. Sci. USA, 89: 7866-7870, 1992). For comparison, the sequences of the lacI genes in two to five mutants from each mouse were determined, and a total of 75 mutations (70 different mutations) was detected. In exposed mice, 55% (24 of 44) of the mutations in lacI were substitutions at AxT bp. In controls, substitutions at AT bp comprised only 20% of the recovered mutations in either hprt exon 3 (1 of 5) or lacI (5 of 26). These data indicate that the lacI mutation assay is less sensitive than the hprt assay for detecting increases in Mf induced by ENU exposure of mice as indicated by the lower relative increase in Mf in the lacI gene, but, given a 6-week expression time, the types of mutations induced by ENU in the transgene reflect those observed in the native transcribed gene.

Animals↗
PubMed1990

Characterization of endothelin converting enzyme in rat lung.

An enzyme activity which converts human big endothelin (1-38) to endothelin (1-21) and a C-terminal fragment (CTF, 22-38) was identified in a plasma membrane fraction prepared from rat lung. The conversion activity was optimal at pH 4.0, was inhibited by Pepstatin-A (IC50 = 20 nM), but was not affected by TLCK, Aprotinin, PMSF, E-64, Bestatin, Phosphoramidon or Thiorphan at 40 microM. Metal ions activated the activity by 1.5 - 2.5 fold in the order of Mn+2 greater than Zn+2 = Ca+2 greater than Ba+2. These data suggest that a Pepstatin-A inhibitable, metal ion related aspartic protease may be involved in the conversion of big endothelin to endothelin in rat lung.

Animals↗