SummaryBackgroundUntil now, a proper biomarker(s) to evaluate sarcoidosis activity has not been recognized. The aims of this study were to evaluate the sensitivity and specificity of the two biomarkers of sarcoidosis activity already in use (serum angiotensin converting enzyme – ACE and serum chitotriosidase) in a population of 430 sarcoidosis patients. The activities of these markers were also analyzed in a group of 264 healthy controls.MethodsFour hundred and thirty biopsy positive sarcoidosis patients were divided into groups with active and inactive disease, and groups with acute or chronic disease. In a subgroup of 55 sarcoidosis patients, activity was also assessed by F-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) scanning. Both serum chitotriosidase and ACE levels showed non-normal distribution, so nonparametric tests were used in statistical analysis.ResultsSerum chitotriosidase activities were almost 6 times higher in patients with active sarcoidosis than in healthy controls and inactive disease. A serum chitotriosidase value of 100 nmol/mL/h had the sensitivity of .5% and specificity of 70.0%. A serum ACE activity cutoff value of 32.0 U/L had the sensitivity of 66.0% and the specificity of 54%. A statistically significant correlation was obtained between the focal granulomatous activity detected on 18F-FDG PET/CT and serum chitotriosidase levels, but no such correlation was found with ACE. The levels of serum chitotriosidase activity significantly correlated with the disease duration (P < 0.0001). Also, serum chitotriosidase significantly correlated with clinical outcome status (COS) categories (ρ =0.272, P =0.001).ConclusionsSerum chitotriosidase proved to be a reliable biomarker of sarcoidosis activity and disease chronicity.
Fused deposition modeling (FDM) is a rapidly growing additive manufacturing technology for various applications in field of engineering. Mechanical properties of 3D printed materials in FDM technology depend on various parameters. Literature suggests that type and density of infill are parameters that affecting the mechanical properties of 3D printed materials, and also have direct influence on 3D printing time and amount of 3D printed material. In this paper influence of infill type and density on tensile properties, 3D printing time and amount of 3D printed material will be investigated and presented. Total of 13 different types of infill and for every type it will be tested 9 specimens with different infill density from 10% to 90%. Every specimen would be 3D printed of PLA material with same colour and 3D printing parameters, also at the same position on printer bed to maximally reduce influence of other factors on mechanical properties of material. The obtained results would give us a wider picture of how to maximally save on 3D printing time and amount of material consumed in the production, but to still keep required tensile properties.
Berlin Questionnaire (Serbian version) showed good measurement properties, creating basis for further research of its usefulness as OSA screening tool in populations of interest.
Today, one of the most used material in FDM (fused deposition modelling) 3D printing technology is PLA (polylactic acid). On market today, there are many different companies that producing PLA material filament for 3D printers with different diameter and colours. Previous research showing that there are so many parameters in FDM technology that affect on mechanical properties of 3D printed material like layer height, infill density, temperature etc. Topic of this article is to investigate whether colour of PLA material effect on material tensile properties and in what amount. It will be tested more than 10 different colours of PLA material, and for every colour it will be tested 3 specimens. Specimens are prepared according to ISO 527-2, and all printed with same 3D printing parameters and with 100% infill. Also, all used materials are of same company and for every colour specimen will be 3D printed from same filament spool. All this is done to avoid other parameters to effect on material properties. The results of this study will be useful for colour selection of the PLA material without compromising the material tensile properties of 3D printed product.
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