The purpose of the study was to quantify and compare the effect of CT dose and of size and density of nodules on the detectability of lung nodules and to quantify the influence of CT dose on the size ...of the nodules.
From 50 patients a total of 125 cuboidal regions of interest (3 × 3 × 1.5 cm volumes) showing a single nodule (≤ 8 mm) and 27 normal cuboids were selected. Image sets were reconstructed with the software from raw data simulating different dose levels: 300 (original dose), 220, 180, 140, 100, 80, 60, 50, 40, 30, 20, 10, and 5 reference mAs. A logistic regression model was used to analyze detectability for three blinded readers. Odds ratios were calculated for nodule size smaller than 3 mm versus 3 mm and larger and for nodule attenuation of -300 HU and greater versus less than -300 HU.
Tube current-time settings of 10 mAs and greater were not associated with a significant difference in individual reader sensitivity compared with the standard setting of 300 mAs. At 5 mAs only one reader had a significant decrease in sensitivity, from 82% to 77% (p = 0.0035). According to the odds ratios and logistic regression results, the strongest negative effect on sensitivity can be assumed for low nodule density followed by small nodule size and dose level. The mean nodule volume measurement error between 5 and 300 mAs was 2.2% ± 18% (SD) and much lower than the interobserver volume measurement error rate of 38% ± 45%.
The results show the feasibility of a low-dose CT protocol at 10 mAs for follow-up of lung nodules. Computer-aided volume measurement in follow-up of lung nodules decreases interobserver variability.
We examine oil-specific asphaltene inhibitor chemistry of two chemically distinct asphaltene inhibitors. Laboratory and field tests show oil-specific asphaltene inhibitor performance for two ...geographically distinct crude oils. The crude oils and their corresponding asphaltenes were characterized by total acid number (TAN), elemental analysis, Fourier transform infrared spectroscopy (FTIR), and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT−ICR MS). ESI FT−ICR MS reveals differences in the relative abundance of heteroatom-containing compound classes in the two crude oils and the two asphaltenes. We identify acidic and/or basic species that may be responsible for the observed differences in inhibitor chemistry. Asphaltene inhibitor specificity can be explained by acid−base-type interactions between the inhibitor and polar species in the crude oils or asphaltene fractions. ESI FT−ICR MS provides the first evidence for inhibitor effectiveness related to heteroatom content derived from detailed polar chemical composition.
Retinoic acid (RA) is a fundamental regulator of cell cycle and cell differentiation. Using a leukemic patient-derived
in vitro
model of a non-APL AML, we previously found that RA evokes activation ...of a macromolecular signaling complex, a signalosome, built of numerous MAPK-pathway-related signaling molecules; and this signaling enabled Retinoic-Acid-Response-Elements (RAREs) to regulate gene expression that results in cell differentiation/cell cycle arrest. Toward mechanistic insight into the nature of this novel signaling, we now find that the NUMB cell fate determinant protein is an apparent scaffold for the signalosome. Numb exists in the cell bound to an ensemble of signalosome molecules, including Raf, Lyn, Slp-76, and Vav. Addition of RA induces the expression of Fgr. Fgr binds NUMB, which is associated with (p-tyr)phosphorylation of NUMB and enhanced NUMB-binding and (p-tyr)phosphorylation of select signalosome components, thereby betraying signalosome activation. Signalosome activation is associated with cell differentiation along the myeloid lineage and G1/0 cell cycle arrest. If RA-induced Fgr expression is ablated by a CRISPR-KO; then the RA-induced (p-tyr) phosphorylation of NUMB and enhanced NUMB-binding and (p-tyr)phosphorylation of select signalosome components are lost. The cells now fail to undergo RA-induced differentiation or G1/0 arrest. In sum we find that NUMB acts as a scaffold for a signaling machine that functions to propel RA-induced differentiation and G1/0 arrest, and that Fgr binding to NUMB turns the function on. The Numb fate determinant protein thus appears to regulate the retinoic acid embryonic morphogen using the Fgr Src-Family-Kinase. These mechanistic insights suggest therapeutic targets for a hitherto incurable AML.
An alternative method to extract, quantify, and characterize water-soluble organic (WSO) species in produced water from steam-assisted gravity drainage (SAGD) is evaluated by various techniques. ...Here, we use a 70:30 mixture of cyclohexane/butyl acetate as the solvent for extraction of WSO species from produced water. The ability of the 70:30 cyclohexane/butyl acetate mixture to efficiently isolate higher O x species that are readily identified in production deposits is demonstrated by use of Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometric analysis and fluorescence spectroscopy. These results are compared to industry standard methods that employ extraction with n-hexane and cyclohexane. Results reveal that the 70:30 cyclohexane/butyl acetate solvent system not only extracts more material from produced water than n-hexane or cyclohexane but is also more efficient at extraction of polar species implicated in deposits of interest. Results suggest that a 70:30 cyclohexane/butyl acetate mixture is a better solvent for the quantitative extraction and analysis of WSO in produced water.
Organic solid deposition control (OSDC) is a live oil test capable of simulating the production conditions of oil streams and can generate asphaltene deposits under production system conditions. OSDC ...can also simulate gas lift conditions because the producers are looking for artificial lift methods to produce oil from low-energy reservoirs. In this paper, we present the first compositional study on the OSDC deposits under gas lift conditions and compare it to C7 asphaltenes from the same crude oil precipitated in the laboratory, by use of ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry. Furthermore, deposits collected from chemically treated fluids were also studied. The negative-ion mass spectra of OSDC deposits from untreated crude oil and asphaltene inhibitor (AI)-treated crude oil are richer in acidic species, such as the O x and S x O y polar classes, relative to the parent crude oil. The molecular-weight differences for treated deposits relative to the untreated sample may help explain the deposition tendency in the tests. We infer that a correlation of field asphaltene deposition tendency with laboratory screening tests is essential for the advancement of asphaltene research.
Emergent resistance can be progressive and driven by global signaling aberrations. All-trans retinoic acid (RA) is the standard therapeutic agent for acute promyelocytic leukemia, but 10-20% of ...patients are not responsive, and initially responsive patients relapse and develop retinoic acid resistance. The patient-derived, lineage-bipotent acute myeloblastic leukemia (FAB M2) HL-60 cell line is a potent tool for characterizing differentiation-induction therapy responsiveness and resistance in t(15;17)-negative cells. Wild-type (WT) HL-60 cells undergo RA-induced granulocytic differentiation, or monocytic differentiation in response to 1,25-dihydroxyvitamin D3 (D3). Two sequentially emergent RA-resistant HL-60 cell lines, R38+ and R38-, distinguishable by RA-inducible CD38 expression, do not arrest in G1/G0 and fail to upregulate CD11b and the myeloid-associated signaling factors Vav1, c-Cbl, Lyn, Fgr, and c-Raf after RA treatment. Here, we show that the R38+ and R38- HL-60 cell lines display a progressive reduced response to D3-induced differentiation therapy. Exploiting the biphasic dynamic of induced HL-60 differentiation, we examined if resistance-related defects occurred during the first 24 h (the early or "precommitment" phase) or subsequently (the late or "lineage-commitment" phase). HL-60 were treated with RA or D3 for 24 h, washed and retreated with either the same, different, or no differentiation agent. Using flow cytometry, D3 was able to induce CD38, CD11b and CD14 expression, and G1/G0 arrest when present during the lineage-commitment stage in R38+ cells, and to a lesser degree in R38- cells. Clustering analysis of cytometry and quantified Western blot data indicated that WT, R38+ and R38- HL-60 cells exhibited decreasing correlation between phenotypic markers and signaling factor expression. Thus differentiation induction therapy resistance can develop in stages, with initial partial RA resistance and moderate vitamin D3 responsiveness (unilineage maturation block), followed by bilineage maturation block and progressive signaling defects, notably the reduced expression of Vav1, Fgr, and c-Raf.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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