2,591 research outputs found
Model Selection with PLANN-CR-ARD
No full textThis paper presents a new compensation mechanism to be used with a Partial Logistic Artificial Neural Network for Competing Risks with Automatic Relevance Determination (PLANN-CR-ARD) and tested comprehensibly on a real breast cancer dataset with excellent convergence properties and numerical stability for the non-linear model. The Model Selection is implemented for the PLANN-CR-ARD model, benefiting from a scaling of the prior error term which together with the data error term forms the total error function that is optimized. The PLANN-CR-ARD proves to be an excellent prognostic tool that can be used in regression analysis tasks such as the survival analysis of cancer datasets
Gaps in the traceability chain of human growth hormone measurements
No full textBACKGROUND: Human growth hormone (hGH) is measured for the diagnosis of secretion disorders. These measurements fall under the EU Directive 98/79/EC on in vitro diagnostic medical devices requiring traceability of commercial calibrator values to higher-order reference materials or procedures (Off J Eur Communities 1998 Dec 7; L 331:1-37). External quality assessment schemes show large discrepancies between results from different methods, even though most methods provide results traceable to the recommended International Standard (IS 98/574). The aim of this study was to investigate possible causes for these discrepancies.
METHODS: We investigated the commutability and recovery of hGH in reconstituted IS 98/574. We tested different reconstitution protocols and used 4 different serum matrices for spiking. These IS preparations were measured together with serum samples. We quantified hGH by 5 different methods in 4 different laboratories.
RESULTS: Results from the different methods correlated well for the serum samples. Mean discrepancies between results from different methods were 10-fold differences) and background matrix (relative differences <= 17% for different serum matrices).
CONCLUSIONS: The use of different protocols for reconstitution and spiking of hGH reference preparations affects quantification by immunoassays, potentially leading to a bias between commercial methods, despite the use of calibrators with values claimed to be traceable to the same higher-order reference material
Quantification of growth hormone in serum by isotope dilution mass spectrometry
No full textInter-assay variation of antibody based routine tests is hampering comparability of measurement results for growth hormone (GH) between different laboratories and decision making in clinical practice. Here it is demonstrated, that quantification of GH by isotope dilution mass spectrometry (IDMS) constitutes a way to precise and reliable results which can be referred to in evaluation of performance of commercial test kits. With the IDMS method developed, tryptic cleavage products YSFLQNPQTSLCFSESIPTPSNR (T6) and LEDGSPR (T12) of GH are quantified by LC/MS-MS using the isotopically labeled forms of the peptides as internal standards. The GH cleavage fragments are obtained by whole-serum tryptic proteolysis and then extracted from the resulting mixture by semi-preparative reversed phase liquid chromatography followed by strong cation-exchange chromatography. Method validation basing on recovery of recombinant 22 kDa GH spiked to blank serum in defined amounts covering the intended concentration range (3-30 µg/L) would yield mean recoveries of 101.6% (100.7%), standard deviations of 2.5% (2.4%) and combined uncertainties (_u~c~_) of 3.0% (2.5%) if quantifying T6 (T12) as GH derived fragments, while the LOQ were 1.7 µg/L (2.7 µg/L). Potential to acquisition of reference values is exemplified by application to serum materials used in a recent quality assessment exercise for routine laboratories
Phenyl arsene oxide abolished depolarization evoked ΔCm.
No full text<p>(<i>A</i>) Continuous monitoring of membrane capacitance induced by a depolarizing voltage command from a holding potential of −80 mV to 0 mV of 2×500 ms, separated by 100 ms at −80 mV in an oocyte expressing, Cav1.2 subunits, α<sub>1</sub>1.2, β2A, α<sub>2</sub>δ without (upper <i>left</i>) and with <i>SNARE's:</i> Sx1A, SNAP-25 and SytI (<i>upper right</i>), and with either PAO (10 µM) (<i>lower left)</i> or PAO (10 µm) followed by 2 mM BAL (<i>lower right</i>). (<i>B</i>) Summary <i>of effect of</i> depolarization on C<sub>m</sub>. Groups as in the exemplary recordings shown in (<i>A</i>). <i>ΔC<sub>m</sub></i>, depolarization-induced change of membrane capacitance; (<i>left</i>) bars show mean±SEM (n = 13) and the <i>Effect of depolarization on mean peak Ba<sup>2+</sup> currents:</i> InA (mean±SEM, n = 11; <i>right</i><i>).</i></p
Isolation and characterization of cDNAs differentially expressed between Cd8+ and Cd4+ T cell lines, 2002
No full textTo detect novel molecules involved in immune functions, a subtracted cDNA library between two closely related murine lymphoid cell lines was constructed using the suppression subtractive hybridization (SSH) technique. Both cells are cytotoxic T lymphocytes, however the 2C is a CD8+ cytotoxic T cell line and the 5.9 is an inflammatory CD4+T cell line (Thl). They can both secrete the cytolysin or perforin and are significantly resistant to cell-mediated lysis. When these two cell lines were subjected to prolonged exposure to reagents that deplete cells of ATP (2-deoxyglucose, sodium azide, and potassium cyanide), the 5.9 cell line became substantially susceptible, but the 2C and other CD8+ cell line still stood out as being strikingly resistant to granule- mediated lysis. A modified differential screening of colonies randomly picked from the constructed subtractive cDNA library and RNA blot analysis were used to identify cDNA clones expressed in 2C and/or 5.9 cytotoxic T cell lines. Thirteen cDNA clones were isolated, from which seven were expressed in both cell lines, and only two were expressed in 2C but not in 5.9 cell line. All the isolated cDNA clones were sequenced. A search of the Gene Bank database with the BLAST X program revealed no extensive homology of IB and 3F cDNA clones to known genes. Limited homology respectively to a zinc finger motif and the transcription factor MTF-1 were observed. Also RT-PCR analysis of cells purified from primary mixed lymphocyte reaction, demonstrated that both IB and 3F cDNA clones were expressed only in CD8+ but not in CD4+ purified cells. This approach of employing subtraction coupled with partial cDNA sequence determination can be useful for a first selection of putative functionally relevant molecules
Nuclear Modification Factor for Charged Pions and Protons at Forward Rapidity in Central Au+Au Collisions at 200 GeV
No full textWe present spectra of charged pions and protons in 0-10% central Au+Au collisions at GeV at mid-rapidity () and forward pseudorapidity () measured with the BRAHMS experiment at RHIC. The spectra are compared to spectra from p+p collisions at the same energy scaled by the number of binary collisions. The resulting nuclear modification factors for central Au+Au collisions at both and exhibit suppression for charged pions but not for (anti-)protons at intermediate . The ratios have been measured up to GeV/ at the two rapidities and the results indicate that a significant fraction of the charged hadrons produced at intermediate range are (anti-)protons at both mid-rapidity and
Mass Composition of UHECRs from <i>X</i><sub>max</sub> Distributions Recorded by the Pierre Auger and Telescope Array Observatories
No full textIn this paper we infer the mass composition of the ultra high energy cosmic rays (UHECRs) from measurements of Xmax distributions recorded at the Pierre Auger (2014) and Telescope Array (TA) (2016) Observatories, by fitting them with all possible combinations of Monte Carlo (MC) templates from a large set of primary species (p, He, C, N, O, Ne, Si and Fe), as predicted by EPOS-LHC, QGSJETII-04 and Sibyll 2.1 hadronic interaction models. We use the individual fractions of nuclei reconstructed from one experiment in each energy interval to build equivalent MC Xmax distributions, which we compare with the experimental Xmax distributions of the other experiment, applying different statistical tests of compatibility. The results obtained from both experiments confirm that the mass composition of the UHECRs is dominated (≳70%) by protons and He nuclei in the energy range investigated lgE(eV) = [17.8–19.3] (Auger) and lgE(eV) = [18.2–19.0] (TA). The indirect comparisons between the Xmax distributions recorded by the two experiments show that the degree of compatibility of the two datasets is good, even excellent in some high energy intervals, especially above the ankle (lgE(eV)∼18.7). However, our study reveals that, at low energies, further effort in data analysis is required in order to harmonize the results of the two experiments
Tropospheric OH and Cl levels deduced from non-methane hydrocarbon measurements in a marine site
No full textIn situ continuous hourly measurements of C<sub>2</sub>&ndash;C<sub>8</sub> non-methane hydrocarbons (NMHC<sub><I>S</I></sub>) have been performed from March to October 2006 at two coastal locations (natural and rural) on the island of Crete, in the Eastern Mediterranean. Well defined diel variations were observed for several short lived NMHC<sub><I>S</I></sub> (including ethene, propene, n-butane, n-pentane, n-hexane, 2-methyl-pentane). The daytime concentration of hydroxyl (OH) radicals estimated from these experimental data varied from 1.3&times;10<sup>6</sup> to ~4.0&times;10<sup>6</sup> radical cm<sup>&minus;3</sup>, in good agreement with box-model simulations. In addition the relative variability of various hydrocarbon pairs (at least 7) was used to derive the tropospheric levels of Cl atoms. The Cl atom concentration has been estimated to range between 0.6&times;10<sup>4</sup> and 4.7&times;10<sup>4</sup> atom cm<sup>&minus;3</sup>, in good agreement with gaseous hydrochloric acid (HCl) observations in the area. Such levels of Cl atoms can be of considerable importance for the oxidation capacity of the troposphere on a regional scale
Assessment of genetic diversity of some <i>Brassica napus</i> L. cultivars revealed by molecular markers and phenotypic evaluation
No full text568-575The genetic diversity of 50 oilseed rape cultivars was studied using phenotypic evaluation and molecular markers. For the phenotypic evaluation, seven morphological traits were analysed. Euclidian distances among mean values of the obtained data, after the morphological evaluation of genotypes, were used to form a matrix for the construction of a dendrogram. For the molecular studies, RAPD and SSR markers were employed. In the RAPD analysis, 20 decamer primers were used, which gave 301 fragments, where 215 were polymorphic. The SSR analysis used 55 primers, which gave 123 polymorphic fragments. In order to determine the genetic diversity between the oilseed rape cultivars, both RAPD and SSR data were used. With this data, genetic similarity (GS) was estimated, which led to generate two similarity matrices. These two matrices were correlated using the Mantel test and the final matrice was used to design an UPGMA dendrogram using cluster analysis. Among the studied cultivars, significant genetic variability was obtained both at the morphological and molecular level. The obtained dendrogram for the morphological traits and for the RAPD and SSR results were compared. In both the cases, the genotypes were grouped after the geographical origin
The management of cultural adjustment: Central-South-East European ethnic minorities in the USA
No full textThe paper focuses on one particular instance in the management of change as accomplished/implemented in the USA by the ethnic minorities originally from Italy, Greece and Romania. The author presents a diachronic survey of the literature against the author’s own findings. The paper identifies common patterns in the cultural adjustment of all three ethnic groups surveyed and analyses them against the specific developmental pressures in each group. Historic, economic and sociological data contribute to outlining the distinct profile of each ethnic groups under investigation, as well as the assimilation patterns at work throughout its evolution in the new US cultural environment.ethnicity affirmed, ethnicity under attack, peripheral ethnicity
- …
