Search results for "Magnification"
showing 10 items of 88 documents
Environmental and biological factors are joint drivers of mercury biomagnification in subarctic lake food webs along a climate and productivity gradi…
2021
Subarctic lakes are getting warmer and more productive due to the joint effects of climate change and intensive land-use practices (e.g. forest clear-cutting and peatland ditching), processes that potentially increase leaching of peat- and soil-stored mercury into lake ecosystems. We sampled biotic communities from primary producers (algae) to top consumers (piscivorous fish), in 19 subarctic lakes situated on a latitudinal (69.0-66.5 degrees N), climatic (+3.2 degrees C temperature and +30% precipitation from north to south) and catchment land-use (pristine to intensive forestry areas) gradient. We first tested how the joint effects of climate and productivity influence mercury biomagnific…
Diet and habitat use influence Hg and Cd transfer to fish and consequent biomagnification in a highly contaminated area: Augusta Bay (Mediterranean S…
2016
Abstract Total mercury (T-Hg) and cadmium (Cd) were measured in twenty species of fish to study their bioaccumulation patterns and trophodynamics in the Augusta Bay food web. Adult and juvenile fish were caught in 2012 in Priolo Bay, south of the Augusta harbour (Central Mediterranean Sea), which is known for the high trace element and polycyclic aromatic hydrocarbon contamination level. T-Hg concentration was found to significantly increase along δ15N and from pelagic to benthic sedentary fish, revealing a marked influence of trophic position and habitat use (sensu Harmelin 1987) on T-Hg accumulation within ichthyofauna. Cd showed the opposite pattern, in line with the higher trace element…
Comparative measurement of collagen bundle orientation by Fourier analysis and semiquantitative evaluation: reliability and agreement in Masson's tri…
2017
Summary Measurement of collagen bundle orientation in histopathological samples is a widely used and useful technique in many research and clinical scenarios. Fourier analysis is the preferred method for performing this measurement, but the most appropriate staining and microscopy technique remains unclear. Some authors advocate the use of Haematoxylin-Eosin (H&E) and confocal microscopy, but there are no studies comparing this technique with other classical collagen stainings. In our study, 46 human skin samples were collected, processed for histological analysis and stained with Masson's trichrome, Picrosirius red and H&E. Five microphotographs of the reticular dermis were taken with a 20…
Size invariance in visual number discrimination
1991
This study deals with the observer's ability to discriminate the numerosity of two random dot-patterns irrespective of their relative size. One of these two patterns was a reference one that was always composed of 32 dots randomly distributed within a K x K invisible square window (K = 1.92 degrees). The second one was the test pattern with one of the five magnifications (K = 0.64 degrees, 1.28 degrees, 1.92 degrees, 2.56 degrees, 3.20 degrees) and the relative number of dots varied on 11 levels (N = -15, -12, -9, -6, -3, 0, 3, 6, 9, 12, or 15 dots). The observer's task was to indicate which of the two patterns contained more dots. The results show that the stimulus size, as an irrelevant s…
A retrospective radiographic evaluation of the anterior loop of the mental nerve: Comparison between panoramic radiography and cone beam computerized…
2014
Objectives: To compare the prevalence and the length of mental loop, measured with panoramic radiography (PR) and cone beam computerized tomography (CBCT). Material and Methods: PG and CBCT images where analyzed by a single calibrated examiner to determine the presence and the position of the mental foramen (MF), its distance to the lower mandible border, the anterior length of the mental loop (ML) and the bone quality in 82 PR and 82 CBCT. Results: ML was identified in 36.6 % of PR and 48.8 % of CBCT. PR showed a magnification of 1.87 when compared to CBCT. The mean of anterior extension of the inferior alveolar nerve and the distance to the inferior border of the mandible was higher for P…
Value of chromoendoscopy and magnification endoscopy in the evaluation of duodenal abnormalities: a prospective, randomized comparison.
2003
Background and study aims Endoscopic staining methods are increasingly being used to evaluate lesions in the esophagus and colon. The aim of this prospective study was to investigate chromoendoscopy and magnification endoscopy for the evaluation of mucosal lesions in the duodenum. Patients and methods Consecutive patients were randomly assigned to undergo conventional endoscopy without staining (group A) or intravital staining of the duodenal mucosa with indigo carmine and evaluation with a conventional video endoscope (group B) or a magnification endoscope (group C). Visible lesions were characterized before and after staining, and biopsies were taken for histological assessment. Results A…
Change in pupil size after implantation of an iris-fixated toric phakic intraocular lens
2005
Purpose To evaluate the changes in pupil size after implantation of an iris-supported toric phakic intraocular lens (TPIOL) for correction of myopia and hyperopia with astigmatism. Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods Twenty-two myopic eyes and 9 hyperopic eyes were included in the study. The mean age of the 2 groups was 34 years and 40 years, respectively. The scotopic pupil size was measured with a handheld infrared pupillometer (Colvard, Oasis Medical) before and 6 months after implantation of the TPIOL. All examinations were performed under scotopic conditions after 2 minutes of dark adaptation with the fellow eye covered. Intraindi…
The internal auditory artery: (embryology, anatomy, angiography, pathology).
1975
A review of the literature on the embryology, anatomy and angiography of the internal auditory artery has shown that there may be considerable variation as to the origin and number of internal auditory arteries. The present study, based on serial magnification angiographies of the internal auditory artery, has demonstrated 7 variants of the origin of this artery although in 45.4% of cases the internal auditory artery arose from the anterior inferior cerebellar artery. For the diagnosis of pathological processes in the cerebellopontine angle (tumors, sudden deafness, vascular abnormalities) magnification angiography is of special importance. Acoustic neurinomas in particular can be diagnosed…
A multicentric randomized study comparing two techniques of magnification assisted loop excision of high-grade cervical intraepithelial neoplasia: vi…
2013
Purpose: To compare loop excisions of cervical intraepithelial neoplasia grade 2 or worse (CIN 2+) under video exoscopy, or colposcopic guidance, with respect to safety and effectiveness. Methods: Prospective multicentric randomized trial of 300 patients, undergoing loop excision for CIN 2+ either under video exoscopy (group A) or colposcope (group B) guidance. Intra- and post-operative complications, resection margins, and removed cervical volume in both groups were evaluated. Results: 19.3% of patients in video exoscopy group and 15.5% in colposcopy group (p = 0.67) had transformation zone (TZ) 3. 45/151 (29.8%) of group A patients and 48/149 (32.2%) of group B patients underwent top-hat …
Effect of different ergonomic supports on muscle activity of dentists during posterior composite restoration
2019
BackgroundThe aim of this study was to evaluate the effect of different ergonomic supports on the muscle activity of two trunk muscles while a group of dentists performed a common dental procedure on a phantom head, divided into three tasks.MethodsA one-way repeated measures study (ANOVA) was conducted on a group of 36 dentists. The middle trapezius and lumbar erector spinae muscles were measured with and without the use of different ergonomic supports (ergonomic stool, magnification lenses and both) using a portable surface electromyography (sEMG) device. Intraclass correlation coefficients (ICCs) and the absolute standard error of measurement (SEM) were used to establish the reliability o…