652 research outputs found

    MECHANICAL PROPERTIES OF 3D PRINTED FACIAL PROSTHESES COMPARED TO HANDMADE SILICONE POLYMER PROSTHESES

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    Purpose: To evaluate the mechanical properties of the 3D printed starch models infiltrated with maxillofacial silicone polymers used for fabrication of maxillofacial prostheses compared to the mechanical properties of pure silicone polymer models. Materials and methods: The test and control specimens were designed according to industry standards ASTM specifications using SolidWorks 2008 software for testing tensile strength tear strength, percentage elongation and hardness properties of starch infiltrated silicone polymer. Ten Dumbbell-shaped specimens and ten Trousershaped specimens with four hardness test specimens were printed by Zcorp 510 3D printer and infiltrated with Sil-25 maxillofacial silicone polymer. Whereas, control samples made from pure Sil-25 silicone polymers using a stainless steel mould and following a similar specification of test specimens. Lloyd LRX tensile instrument; load rating 100 N at a constant crosshead speed of 25 mm/min for testing tensile, tear strength and percentage elongation and Hardness Tester (England) was used to measure shore A durometer hardness. Results: Silicone polymer infiltrated starch (test) specimens demonstrated significantly lower tensile strength, tear strength and percentage elongation than the pure silicone polymer (control) samples (p<0.05). However, a significant increase (p<0.05) in the hardness of the printed specimens was recorded against the pure silicone samples. Conclusion: The 3D printed soft tissue prostheses – the final product showed significantly different mechanical properties compared to the handmade prostheses; they were significantly harder and reported lower mechanical properties

    MECHANICAL PROPERTIES OF 3D PRINTED FACIAL PROSTHESES COMPARED TO HANDMADE SILICONE POLYMER PROSTHESES

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    Purpose: To evaluate the mechanical properties of the 3D printed starch models infiltrated with maxillofacial silicone polymers used for fabrication of maxillofacial prostheses compared to the mechanical properties of pure silicone polymer models. Materials and methods: The test and control specimens were designed according to industry standards ASTM specifications using SolidWorks 2008 software for testing tensile strength tear strength, percentage elongation and hardness properties of starch infiltrated silicone polymer. Ten Dumbbell-shaped specimens and ten Trousershaped specimens with four hardness test specimens were printed by Zcorp 510 3D printer and infiltrated with Sil-25 maxillofacial silicone polymer. Whereas, control samples made from pure Sil-25 silicone polymers using a stainless steel mould and following a similar specification of test specimens. Lloyd LRX tensile instrument; load rating 100 N at a constant crosshead speed of 25 mm/min for testing tensile, tear strength and percentage elongation and Hardness Tester (England) was used to measure shore A durometer hardness. Results: Silicone polymer infiltrated starch (test) specimens demonstrated significantly lower tensile strength, tear strength and percentage elongation than the pure silicone polymer (control) samples (p<0.05). However, a significant increase (p<0.05) in the hardness of the printed specimens was recorded against the pure silicone samples. Conclusion: The 3D printed soft tissue prostheses – the final product showed significantly different mechanical properties compared to the handmade prostheses; they were significantly harder and reported lower mechanical properties

    MECHANICAL PROPERTIES OF 3D PRINTED FACIAL PROSTHESES COMPARED TO HANDMADE SILICONE POLYMER PROSTHESES

    Get PDF
    Purpose: To evaluate the mechanical properties of the 3D printed starch models infiltrated with maxillofacial silicone polymers used for fabrication of maxillofacial prostheses compared to the mechanical properties of pure silicone polymer models. Materials and methods: The test and control specimens were designed according to industry standards ASTM specifications using SolidWorks 2008 software for testing tensile strength tear strength, percentage elongation and hardness properties of starch infiltrated silicone polymer. Ten Dumbbell-shaped specimens and ten Trousershaped specimens with four hardness test specimens were printed by Zcorp 510 3D printer and infiltrated with Sil-25 maxillofacial silicone polymer. Whereas, control samples made from pure Sil-25 silicone polymers using a stainless steel mould and following a similar specification of test specimens. Lloyd LRX tensile instrument; load rating 100 N at a constant crosshead speed of 25 mm/min for testing tensile, tear strength and percentage elongation and Hardness Tester (England) was used to measure shore A durometer hardness. Results: Silicone polymer infiltrated starch (test) specimens demonstrated significantly lower tensile strength, tear strength and percentage elongation than the pure silicone polymer (control) samples (p<0.05). However, a significant increase (p<0.05) in the hardness of the printed specimens was recorded against the pure silicone samples. Conclusion: The 3D printed soft tissue prostheses – the final product showed significantly different mechanical properties compared to the handmade prostheses; they were significantly harder and reported lower mechanical properties

    Remarks on the k-error linear complexity of p(n)-periodic sequences

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    Recently the first author presented exact formulas for the number of 2ⁿn-periodic binary sequences with given 1-error linear complexity, and an exact formula for the expected 1-error linear complexity and upper and lower bounds for the expected k-error linear complexity, k >2, of a random 2ⁿn-periodic binary sequence. A crucial role for the analysis played the Chan-Games algorithm. We use a more sophisticated generalization of the Chan-Games algorithm by Ding et al. to obtain exact formulas for the counting function and the expected value for the 1-error linear complexity for pⁿn-periodic sequences over Fp, p prime. Additionally we discuss the calculation of lower and upper bounds on the k-error linear complexity of pⁿn-periodic sequences over Fp

    Temperature Dependence of the Dielectric Properties of Rubber Wood

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    The effect of temperature on the dielectric properties of rubber wood were investigated in three anisotropic directions-longitudinal, radial, and tangential, and at different measurement frequencies. Low frequency measurements were conducted with a dielectric spectrometer, and high frequencies used microwave applied with open-ended coaxial probe sensors. Dielectric constants and dielectric loss factors were measured at temperatures from 25 to 100°C. A large dielectric dispersion occurred at frequencies less than 10 Hz and at temperatures more than 60°C. The minimum peak value of the dielectric loss factors shifted towards higher frequencies at higher temperatures in all three grain directions. The tangential direction showed the highest activation energy. The dielectric constant decreased as frequency increased from 1 to 10 GHz, and thereafter remained unchanged with additional frequency increases. The dielectric constant exhibited higher values at higher temperatures. The dielectric loss factor showed a peak value at around 10 GHz at 25°C

    The prediction of fatigue using speech as a biosignal

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    Automatic systems for estimating operator fatigue have application in safety-critical environments. We develop and evaluate a system to detect fatigue from speech recordings collected from speakers kept awake over a 60-hour period. A binary classification system (fatigued/not-fatigued) based on time spent awake showed good discrimination, with 80 % unweighted accuracy using raw features, and 90 % with speaker-normalized features. We describe the data collection, feature analysis, machine learning and cross-validation used in the study. Results are promising for real-world applications in domains such as aerospace, transportation and mining where operators are in regular verbal communication as part of their normal working activities

    Вплив харчової добавки "магнетофуд" на структурно-механічні властивості формового желейного мармеладу з різними структуроутворювачами

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    Development of resource- and energy-saving technologies for the production of high-quality jelly and pastille products with an extended shelf life is one of the most urgent challenges of the modern confectionery industry. It is proposed to use the "Magnetofood" mineral food supplement, which holds a high functional and technological potential and may independently form the structural and mechanical properties of jelly pastes, and also affect the gelling agents, entering into chemical and electrostatic interactions therewith. Therefore, the "Magnetofood" food supplement may influence several technological properties in the food jelly system at once: acting as a stabilizer, a thickener, a gelling agent, while improving the quality, consumer properties and extending the shelf life of molded fruit jelly products. The aim of the study is to improve the structural and mechanical properties of molded fruit jelly products by introducing the "Magnetofood" food supplement. Standard and generally accepted methods were used in the course of structural and mechanical studies (viscosity and thixotropic characteristics on the Reotest-2 rotation viscometer, strength characteristics on the AR-4/1 penetrometers). It has been established that the introduction of the "Magnetofood" food supplement into jelly pastes in the amount of 0.15 % of the total weight of raw material improves the consistency, structure, strength and form: the degree of structuring and viscosity of the jelly pastes increases over the entire shear stress range (1.5-40 s⁻¹) 2.9 times for pastes on agar and 1.85 times for pastes on pectin; the temperature effect on the effective viscosity of jelly pastes is slowed down by (50-75) Pa · s on average, destruction processes are also slowed down 1.1 times, and the recovery processes of the jelly structure after the mechanical effect ceases are accelerated by 3.8%, increasing its thixotropic ability by 7.5% in jelly pastes on agar and by 6.0% in jelly pastes on pectin; jelly strength on agar increases by (10-12)%, and by (7-9) % on pectin; the speed of structurization of jelly pastes on agar increases by a factor of 1.3-1.7, and by a factor of 1.1-1.6 on pectin.Однією з актуальних проблем сучасної кондитерської промисловості є розробка ресурсо- і енергозберігаючих технологій виробництва високоякісних мармеладо-пастильних виробів зі збільшеним терміном придатності. Пропонується використання мінеральної харчової добавки "Магнетофуд", яка володіє високим функціонально-технологічним потенціалом і може як самостійно формувати структурно-механічні властивості желейних мас, так і впливати на гелеутворювач, вступаючи з ним в хімічні і електростатичні взаємодії. Тому, харчова добавка "Магнетофуд" може впливати відразу на кілька технологічних властивостей в харчовій желейної системі: бути стабілізатором, загусником, драглеутворювачем, при цьому покращуючи якість, споживчі властивості і продовжуючи терміни зберігання формового желейного мармеладу. Метою дослідження є покращення структурно-механічних властивостей формового желейного мармеладу шляхом введення харчової добавки "Магнетофуд". Під час проведення структурно-механічних (в’язкостних і тиксотропних характеристик на ротаційному віскозиметрі Реотест-2, міцності на пенетрометри АР-4/1) досліджень були використані загальноприйняті та стандартні методики

    Gene and protein expression of glucose transporter 1 and glucose transporter 3 in human laryngeal cancer—the relationship with regulatory hypoxia-inducible factor-1α expression, tumor invasiveness, and patient prognosis

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    Increased glucose uptake mediated by glucose transporters and reliance on glycolysis are common features of malignant cells. Hypoxia-inducible factor-1α supports the adaptation of hypoxic cells by inducing genes related to glucose metabolism. The contribution of glucose transporter (GLUT) and hypoxia-inducible factor-1α (HIF-1α) activity to tumor behavior and their prognostic value in head and neck cancers remains unclear. The aim of this study was to examine the predictive value of GLUT1, GLUT3, and HIF-1α messenger RNA (mRNA)/protein expression as markers of tumor aggressiveness and prognosis in laryngeal cancer. The level of hypoxia/metabolic marker genes was determined in 106 squamous cell laryngeal cancer (SCC) and 73 noncancerous matched mucosa (NCM) controls using quantitative realtime PCR. The related protein levels were analyzed by Western blot. Positive expression of SLC2A1, SLC2A3, and HIF-1α genes was noted in 83.9, 82.1, and 71.7 % of SCC specimens and in 34.4, 59.4, and 62.5 % of laryngeal cancer samples. Higher levels of mRNA/protein for GLUT1 and HIF-1α were noted in SCC compared to NCM (p<0.05). SLC2A1 was found to have a positive relationship with grade, tumor front grading (TFG) score, and depth and mode of invasion (p<0.05). SLC2A3 was related to grade and invasion type (p<0.05). There were also relationships of HIF-1α with pTNM, TFG scale, invasion depth and mode, tumor recurrences, and overall survival (p<0.05). In addition, more advanced tumors were found to be more likely to demonstrate positive expression of these proteins. In conclusion, the hypoxia/metabolic markers studied could be used as molecular markers of tumor invasiveness in laryngeal cancer.This work was supported, in part, by the statutory fund of the Department of Cytobiochemistry, University of Łódź, Poland (506/811), and by grant fromtheNational Science Council, Poland (N403 043 32/2326)

    A Genome-Wide Association Study Provides New Evidence That CACNA1C Gene is Associated With Diabetic Cataract

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    PURPOSE: Diabetic cataract is one of the major eye complications of diabetes. It was reported that cataract occurs two to five times more frequently in patients with diabetes compared with those with no diabetes. The purpose of this study was to identify genetic contributors of diabetic cataract based on a genome-wide association approach using a well-defined Scottish diabetic cohort. METHODS: We adapted linked e-health records to define diabetic cataract. A diabetic cataract case in this study was defined as a type 2 diabetic patient who has ever been recorded in the linked e-health records to have cataracts in both eyes or who had previous cataract extraction surgeries in at least one eye. A control in this study was defined as a type 2 diabetic individual who has never been diagnosed as cataract in the linked e-health records and had no history of cataract surgeries. A standard genome-wide association approach was applied. RESULTS: Overall, we have 2341 diabetic cataract cases and 2878 controls in the genetics of diabetes audit and research in Tayside Scotland (GoDARTS) dataset. We found that the P value of rs2283290 in the CACNA1C gene was 8.81 × 10(−10), which has reached genome-wide significance. We also identified that the blood calcium level was statistically different between diabetic cataract cases and controls. CONCLUSIONS: We identified supporting evidence that CACNA1C gene is associated with diabetic cataract. The role of calcium in the cataractogenesis needs to be reevaluated in future studies
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