Metacognitive Judgments in a Simulated Luggage Screening Task

2005 ◽  
Vol 49 (17) ◽  
pp. 1620-1624 ◽  
Author(s):  
Jason S. McCarley ◽  
Jessica Gosney
Keyword(s):  
Potential Role ◽  
Search Task ◽  
Search Behavior ◽  
Learning Task ◽  
Search Procedure ◽  
X Ray ◽  
Metacognitive Judgments ◽  
Baggage Screening ◽  
Luggage Screening

A pair of experiments examined the accuracy and potential role of predictive metacognitive judgments in a simulated baggage screening task. Procedure was modeled after the ease-of-learning task (Underwood, 1966). Subjects searched for knives hidden in x-ray images of passenger bags. Before performing the search task, subjects viewed each stimulus without the embedded target and rated the likelihood of finding the target if it was hidden in that image. Experiment 1 used a 2IFC search task. Experiment 2 used a speeded yes-no search procedure. Results suggest that predictive metacognitive judgments are only modestly accurate, but that the information on which such judgments are based is nonetheless used to regulate search behavior

Edx Spectrum Imaging of Bulk Specimens: Its Role in Quantitative X-Ray Microanalysis

2001 ◽  
Vol 7 (S2) ◽  
pp. 704-705
Author(s):  
I.M. Anderson
Keyword(s):  
Potential Role ◽  
X Rays ◽  
Analysis Software ◽  
Full Spectrum ◽  
Computing Power ◽  
X Ray ◽  
Data Files ◽  
Spectrum Imaging ◽  
Compositional Variations

Energy-dispersive X-ray (EDX) spectrum imaging, where a full spectrum is acquired at each pixel in a rastered image, combines the advantages of imaging and analysis for quantitative compositional mapping. This method has great advantages for the analysis of compositional variations, because the contrast inherent in EDX spectrum images arises from the distinctiveness of the characteristic X-ray spectra in various regions of the surveyed microstructure. EDX spectrum imaging provides for simultaneous spatial, spectral and temporal resolution of the X-rays emitted from the specimen. Many EDX manufacturers have incorporated a spectrum imaging capability within their acquisition and analysis software, and ongoing improvements in computing power will enhance the practicality of spectrum imaging methods, in particular the acquisition, manipulation and analysis of the large raw data files that are generated with this method. This paper surveys the potential role of spectrum imaging in tasks that support true quantitative X-ray microanalysis of bulk specimens: robust qualitative analysis, the construction of representative spectra that describe the specimen, and the extraction of elemental concentrations from the representative spectra.

Crystal structure of the FAS1 domain of the hyaluronic acid receptor stabilin-2

2018 ◽  
Vol 74 (7) ◽  
pp. 695-701 ◽  
Author(s):  
Aleksandra Twarda-Clapa ◽  
Beata Labuzek ◽  
Dobroslawa Krzemien ◽  
Bogdan Musielak ◽  
Przemyslaw Grudnik ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Cancer Metastasis ◽  
Potential Role ◽  
Three Dimensional ◽  
Protein Fragments ◽  
Acid Receptor ◽  
X Ray ◽  
Insight Into

Recent research has identified a potential role of the hyaluronic acid receptor stabilin-2 (Stab2) in cancer metastasis. Stab2 belongs to a group of scavenger receptors and is responsible for the clearance of more than ten ligands, including hyaluronic acid (HA). In vivo experiments on mice have shown that the absence of Stab2, or its blocking by an antibody, effectively opposes cancer metastasis, which is accompanied by an increase in the level of circulating HA. Knowledge of ligand recognition and signal transduction by Stab2 is limited and no three-dimensional structures of any protein fragments of this receptor have been solved to date. Here, a high-resolution X-ray structure of the seventh FAS1 domain of Stab2 is reported. This structure provides the first insight into the Stab2 structure.

scholarly journals Exoribonuclease and Endoribonuclease Activities of RNase BN/RNase Z both Function in Vivo

2012 ◽  
Vol 287 (42) ◽  
pp. 35747-35755 ◽  
Author(s):  
Tanmay Dutta ◽  
Arun Malhotra ◽  
Murray P. Deutscher
Keyword(s):  
Potential Role ◽  
Wild Type ◽  
X Ray ◽  
E Coli ◽  
Phage T4 ◽  
A Cell ◽  
Rnase Z

Escherichia coli RNase BN, a member of the RNase Z family of endoribonucleases, differs from other family members in that it also can act as an exoribonuclease in vitro. Here, we examine whether this activity of RNase BN also functions in vivo. Comparison of the x-ray structure of RNase BN with that of Bacillus subtilis RNase Z, which lacks exoribonuclease activity, revealed that RNase BN has a narrower and more rigid channel downstream of the catalytic site. We hypothesized that this difference in the putative RNA exit channel might be responsible for the acquisition of exoribonuclease activity by RNase BN. Accordingly, we generated several mutant RNase BN proteins in which residues within a loop in this channel were converted to the corresponding residues present in B. subtilis RNase Z, thus widening the channel and increasing its flexibility. The resulting mutant RNase BN proteins had reduced or were essentially devoid of exoribonuclease activity in vitro. Substitution of one mutant rbn gene (P142G) for wild type rbn in the E. coli chromosome revealed that the exoribonuclease activity of RNase BN is not required for maturation of phage T4 tRNA precursors, a known specific function of this RNase. On the other hand, removal of the exoribonuclease activity of RNase BN in a cell lacking other processing RNases leads to slower growth and affects maturation of multiple tRNA precursors. These findings help explain how RNase BN can act as both an exo- and an endoribonuclease and also demonstrate that its exoribonuclease activity is capable of functioning in vivo, thus widening the potential role of this enzyme in E. coli.

scholarly journals Sickle cell patient with an acute chest syndrome and a negative chest X-ray: Potential role of the ventilation and perfusion (V/Q) lung scan

2003 ◽  
Vol 74 (3) ◽  
pp. 214-215 ◽  
Author(s):  
Lawrence Feldman ◽  
Robert Gross ◽  
Jack Garon ◽  
Anitha Nallari ◽  
Navleen Kaur ◽  
...  
Keyword(s):  
Sickle Cell ◽  
Potential Role ◽  
Acute Chest Syndrome ◽  
X Ray ◽  
Lung Scan ◽  
Chest X Ray ◽  
Ventilation And Perfusion

Electron Energy-Loss and Energy Dispersive X-Ray Spectros-Copy Studies of Diffusion Bonded Cu-Al2O3 Interfaces

1997 ◽  
Vol 3 (S2) ◽  
pp. 993-994
Author(s):  
R. Hashimoto ◽  
E. S. K. Menon ◽  
M. Saunders ◽  
A. G. Fox
Keyword(s):  
Grain Boundary ◽  
Energy Loss ◽  
Electron Energy ◽  
Potential Role ◽  
Energy Dispersive ◽  
Commercial Alumina ◽  
X Ray ◽  
Metal Ceramic ◽  
Electron Energy Loss

The metal-ceramic interface between copper and alumina has been studied by TEM, Electron Energy-Loss Spectroscopy (EELS), and Energy Dispersive X-ray spectroscopy (EDX). of partic-ular interest is the potential role of silicon which is the major impurity in commercial alumina. This investigation focuses on the presence and distribution of silicon within the bulk alumina and at the diffusion bonded CU-AI2O3 interface using a Topcon 002B TEM equipped with an EDAX EDX detector and a Gatan Imaging Filter. The interface was created under vacuum by diffusion bonding of 100/xm copper foils (99.999% purity) pressed between polished alumina substrates (∼99.5% purity) for several hours at ∼90% of the melting temperature of the metal.An initial investigation of the bulk AI2O3 indicated that the majority of the Si occurred at the triple points. A typical example is shown in Fig. la. EDX spectra acquired with a 6nm probe from the center of the junction (Fig. lbi) and at the grain boundary indicate that the Si wets the grain boundary to a limited extent.

scholarly journals Potential Role of Hydroxyapatite Nanocrystalline for Early Diagnostics of Ovarian Cancer

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1741
Author(s):  
Ruslana Chyzhma ◽  
Artem Piddubnyi ◽  
Sergey Danilchenko ◽  
Olha Kravtsova ◽  
Roman Moskalenko
Keyword(s):  
Ovarian Cancer ◽  
Potential Role ◽  
Ovarian Tumors ◽  
Energy Dispersive ◽  
Mineral Component ◽  
Early Diagnostics ◽  
Psammoma Bodies ◽  
X Ray ◽  
Malignant Neoplasia

Calcification is one of the clinical and morphological manifestations of ovarian tumors and it begins at the initial stages of carcinogenesis. Thus, this process can be used for the early diagnostics of some malignant ovarian tumors. We compared the results of ultrasound and histology and found that calcifications of a size less than 200 μm are not detected by ultrasound. These calcified structures are round fragile particles of different sizes. In the EDX (Energy-dispersive X-ray spectroscopy) spectra, the main lines were from Ca and P, and the ratio of these elements corresponds to hydroxyapatite. Thus, we established that hydroxyapatite is the main mineral component of ovarian psammoma bodies and could be used for early diagnostics of ovarian malignant neoplasia.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

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