Objective(s): We evaluated EDGE ARTIFACTs in relation to phantom diameter and reconstruction parameters in point spread function (PSF) -based positron emission tomography (PET) image reconstruction.Methods: PET data were acquired from an original cone-shaped phantom filled with 18F solution (21.9 kBq/mL) for 10 min using a Biograph mCT scanner. The images were reconstructed using the baseline ordered subsets expectation maximization (OSEM) algorithm and the OSEM with PSF correction model. The reconstruction parameters included a pixel size of 1.0, 2.0, or 3.0 mm, 1-12 iterations, 24 subsets, and a full width at half maximum (FWHM) of the post-filter Gaussian filter of 1.0, 2.0, or 3.0 mm. We compared both the maximum recovery coefficient (RCmax) and the mean recovery coefficient (RCmean) in the phantom at different diameters.Results: The OSEM images had no EDGE ARTIFACTs, but the OSEM with PSF images had a dense EDGE delineating the hot phantom at diameters 10 mm or more and a dense spot at the center at diameters of 8 mm or less. The dense EDGE was clearly observed on images with a small pixel size, a Gaussian filter with a small FWHM, and a high number of iterations. At a phantom diameter of 6-7 mm, the RCmax for the OSEM and OSEM with PSF images was 60% and 140%, respectively (pixel size: 1.0 mm; FWHM of the Gaussian filter: 2.0 mm; iterations: 2). The RCmean of the OSEM with PSF images did not exceed 100%.Conclusion: PSF-based image reconstruction resulted in EDGE ARTIFACTs, the degree of which depends on the pixel size, number of iterations, FWHM of the Gaussian filter, and object size.

Aim: This study was designed to determine any profile changes and indentify the role of the most significant factors responsible for these changes.Materials and Methods: Cephalograms of 56 class II Division I patients (36 female and 18 male with mean age of 10 years) were used to analysis any changes in the perioral soft tissue profile before and after the treatment. A correlation analysis and multiple regression analysis (forward) revealed complex interaction between dentition, bony structures and soft tissues of the perioral area.Results: Retraction at the upper lip and increase in lower lip length in boys were more predictable than that of others. Significant soft tissue changes occured in response to orthodontic treatment, Upper lip retraction was shown to be related to the following factors: a- Retraction of upper incisal EDGEs during treatment, b-Retraction of Point A, c- Pretreatment upper sulcus thickness and d- Retraction of sulcus superior.Conclusion: A greater increase in lower lip length takes place with greater amount of maxillary incisa1 EDGE retraction during treatment and a greater amount of sulcus superior retraction.

We review the many causes of motion ARTIFACTs in biopotential recording. We moved several electrode materials at several velocities in electrolytes. ARTIFACT voltage ranged from 350 μV at 0.13% NaC1 concentration and 100 mm/s to 10 mV at 1.3% concentration and 25 mm/s. We present a theoretical model in which adsorbed ions attach to the electrode. Ions in the diffusion layer move with the electrolyte. This separation of charge causes the ARTIFACT. A second source of motion ARTIFACT is cable movement. This causes the polarization potential of the electrodes to have a varying attenuation because the stray capacity of the electrode varies. Experimental and theoretical ARTIFACTs ranged from 1 to 100 mV. ARTIFACT is reduced by using electrodes having large area, electrolytes having high concentration, amplifiers having high impedance, and preamplifiers located at the electrodes.

A 74-year-old woman was referred to the glaucoma unit for pseudoexfoliative glaucoma. Upon presentation, visual acuity in both eyes was 20/30. Intraocular pressure was 18 mmHg in the right eye and 20 mmHg in the left eye with latanoprost eye drops. Ophthalmoscopy revealed a cup-disc ratio of 0.7 with superior neural rim notching in the right eye and concentric cup-disc ratio of 0.6 in the left eye. She underwent central 24-2 automated perimetry with the Humphrey Visual Field Analyzer (HVFA II, Carl Zeiss Meditec, Dublin, USA) using the SITA-fast program. Although she was instructed before the test, she was unable to respond to the early stimuli efficiently which was reflected in lower threshold values for initial test points. The reliability indices were within normal limits except for higher than normal fixation loss. On repeat visual field testing, reliability indices were within normal limits and thresholds of the four areas with poor sensitivity improved and the ARTIFACT disappeared (Fig. 1)….

Background/Objective: To determine the usefulness of twinkling ARTIFACT in detecting urinary stones by sonography according to stone characteristics and sonographic features.Patients and Methods: A prospective study was conducted on 60 urinary stones which had been detected by KUB, IVP or CT scan. First of all, gray scale sonography was performed using 3.5-5 MHz phased array and data including stone size, location and posterior shadow were registered. Then, presence or absence of twinkling ARTIFACT and its intensity with re-spect to different filters (0-3), pulse repetition frequencies (PRF) (244, 1563, and 4864 Hz), and focal zones (at the level of the stone, lower and higher) was assessed using color Doppler sonography. Finally and in the case of ARTIFACT presence, spectral Doppler sonographywas performed. For data analysis, c2 and independent t test was used .Results: The prevalence of twinkling ARTIFACT was 78.3%. ARTIFACT presence in a PRF value of 1563 Hz was significantly related to the echo difference between stone and adjacent tissues (p= 0.001).Conclusion: The above findings together with the fact that twinkling ARTIFACT was strongly present in more than half the cases, indicates the sufficiency in detecting urinary stone

ARTIFACTs are ubiquitous and influential in our world, but their nature and existence are controversial. Several theories have been proposed to explain the ontology of ARTIFACTs. Drawing on Popper's theory of three worlds, this paper suggests a metaphysics for ARTIFACTs along the line of a critical rationalist (CR) approach. This theory distinguishes between three realms of reality: the physical world (World 1), the mental world (World 2), and the world of objective knowlEDGE (World 3). The paper argues that ARTIFACTs have different ontological components that correspond to these three realms, and that each component is real and causal. The paper shows how this perspective can account for the intentional and functional aspects of ARTIFACTs, as well as their dependence on plans that influence different realms of reality. The paper explains how this pluralistic ontology, compared to the rival theories, enables one to explain the relevant ontological problems of ARTIFACTs. The paper also explores how this proposal can lead to a research program encompassing a broader range of technologies, such as social ARTIFACTs. In sum, the paper suggests that Popper's three worlds theory provides a rich and comprehensive framework for understanding the metaphysics of ARTIFACTs.

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