IMPLANT MATERIAL SELECTION USING EXPERT SYSTEM Ristić, Miloš; Manić, Miodrag; Mišić, Dragan ...
Facta Universitatis. Series: Mechanical Engineering,
04/2017, Letnik:
15, Številka:
1
Journal Article
Odprti dostop
Most certainly, in the field of medicine there is a great contribution of new techniques and technologies, which is reflected in an entire system of health care services. Customized implants are both ...fully geometrically and topologically adjusted so as to meet the needs of individual patients, thus making each implant unique. Their production requires joint efforts of a multidisciplinary team of different profile experts who combine their knowledge in the Implant knowledge model. Thus, we develop an expert system which should help or replace humans in the process of Implant material selection. This paper gives an overview of the expert system concept for the given problem. Its task is to carry out a selection of biomaterial (or class of material) for a customized implant. The model significantly improves the efficiency of preoperative planning in orthopaedics.
Introduction/Objective. Acute pancreatitis (AP) is a relatively common disease which in most patients has favorable course. However, in approximately 20% patients, the course of the disease is more ...severe with high mortality (40?50%). The evaluation of disease severity is now primarily based on protocols that includes clinical, laboratory, and radiographic diagnostic procedures, APACHE II score, Ranson score, CT index, and CT necrosis score. Key cells in the immunopathogenesis of AP are T-lymphocytes, and recent studies indicate the role of Th2 and their effector cytokines: interleukin (IL) -4 and interleukin (IL) -5. The purpose of our study was to determine the potential clinical value of IL-4 and IL-5 as biochemical markers for predicting development of severe, necrotizing form of acute pancreatitis with systemic complication such as systemic inflammatory response syndrome (SIRS). Methods. This prospective study included 240 patients hospitalized at The Clinic for Emergency Surgery of Clinical Center of Serbia as AP. Levels of IL-4 and IL-5 in serum were detected using commercial Bender Med Systems (BMS716FF) kits. Results. IL-4 and IL-5 were statistically significant increased on the second day of hospitalization with maximum values on the third day. In patients with severe AP complicated with necrosis and/or sepsis values were rising all through the seventh day. Conclusion. Levels of IL-4 and IL-5 in peripheral blood correlate with SIRS, Ranson score and clinical outcome in AP patients, therefore these cytokines are potential early biomarkers of disease progression and related complications.
Thin-walled cylindrical shells are commonly used in numerous branches of industry. Since they are subjected to axial load, the most common cause of their failure is buckling. This paper provides ...numerical analysis and experimental verification of the buckling of the thin-walled aluminium alloy cylindrical shell with special regard to the influence of dent, positioned in the middle of the shell. Numerical simulation was performed using ANSYS 16.2, and experimental verification was performed by means of hydraulic press Armavir, PSU-50, which was used to subject the specimen to the increasing axial load until the occurrence of buckling. Comparing the results it was concluded that there is significant decrease of the buckling resistance if compared the values of the specimen with no dent, and the specimen with 2 mm deep dent. On the contrary, resistance of the 2 mm and 4 mm dented specimen is quite similar. Position and shape of the deformations occurred due to buckling are matching if experimental and numerical results are compared.
Gear drive units are important components of technical systems (TS) and need to be of high quality. Planetary gear units are very compact and efficient mechanical power transformers, but further ...increase of operating quality level requires the application and development of the new design methodology. The subject of this contribution is presentation of Reliability for design as the new approach of reliability modelling suitable for the new design methodology application, especially for planetary gear units using various kinds of experimental and exploitation data. The methodology follows V-model for TS design which is in this work adapted for gear units design and for presentation of the new methodology based on property based design, axiomatic design and robust design methodology. To this end, the procedure for total reliability of TS decomposition, and methodology for elementary reliability for design of structure components calculation is developed and presented. The reliability for design is established in reverse form of reliability for maintenance which presents common perception of the “reliability” term. This approach is intended to provide further increase of planetary gear unit’s quality and efficient usability of gear unit component resources. The design directions are oriented to providing equal level of elementary reliability of components.
This study explores the ethical perceptions of participants in the financial reporting process in order to comprehend the attitudes and evaluation of the acceptability of different approaches to ...earning manipulations. The paper presents different scenarios for income smoothing, earnings management and big bath. The scenarios include various motives and methods for earning manipulations. The study was carried out on 105 students, 58 in the role of creators of financial reports and 47 in the role of users of financial statements. The results show that there are significant differences in ethical acceptability of various scenarios for earning manipulations, as well as in various methods and motives of manipulation. On the other hand, research has not demonstrated the existence of significant differences in ethical perceptions between the creators and users of financial statements.
Introduction. Trichobezoars presents a rare form of bezoar made of swallowed hair, with clinical manifestation of gastric or intestinal obstruction, gastric ulceration, bleeding, and perforation. It ...is predominantly found in emotionally disturbed or mentally retarded youngsters, who eating their own hair which is clinically known as trichophagia. Patients often deny eating their own hair which makes diagnosis difficult. Case report. We present a case of acute gastric outlet obstruction caused by a giant gastric trichobezoar made of a long thin hair, in a 20-year young female. Although patient had a long history of trichophagia, she did not think her behavior was unusual and she had not been treated before. Following the initial diagnostic procedures, exploratory laparotomy was indicated. After anterior gastrotomy was performed, a massive stomach-shaped trichobezoar was removed. Postoperatively, the patient had a psychiatric consult exam. She recovered well and was discharged without complications. She was referred for further psychiatric follow-up. Conclusion. Trichobezoars are non-digestible collections that usually accumulates in stomach and can extend to small bowel, causing mechanical injury such as hollow viscus obstruction. Patients with acute gastric obstruction caused by a giant trichobezoar require urgent removal of the trichobezoar, to preserve the stomach and avoid further, catastrophic consequences.
The aim of this study was to compare the different diagnostic approaches in detection of gastroesophageal reflux disease in children presented with symptoms suggesting gastroesophageal reflux ...disease.
The study design was cross sectional. The study retrospectively included all children who underwent combined multiple intraluminal impedance and pH (pH-MII) monitoring due to gastrointestinal and/or extraesophageal symptoms suggesting gastroesophageal reflux disease at University Children's Hospital in Belgrade, from July 2012 to July 2016.
A total of 218 (117 boys/101 girls), mean age 6.7 years (range 0.06-18.0 years), met the inclusion criteria. Gastroesophageal reflux disease was found in 128 of 218 children (57.4%) by pH-MII and in 76 (34.1%) children by pH metry alone. Using pH-MII monitoring as gold standard, sensitivity of pH-metry was lowest in infants (22.9%), with tendency to increase in older age groups (reaching 76.4% in children ≥ 9 years). The sensitivity of pH-metry alone in children with extraesophageal symptoms was 38.1%, while the sensitivity of pH-metry in children with gastrointestinal symptoms was 63.8%. Reflux esophagitis was identified in 31 (26.1%) of 119 children who underwent endoscopy. Logistic regression analysis showed that best predictors of endoscopic reflux esophagitis are the longest acid episode (OR = 1.52, p<0.05) and DeMeester reflux composite score (OR = 3.31, p<0.05). The significant cutoff values included DeMeester reflux composite score ≥ 29 (AUC 0.786, CI 0.695-0.877, p<0.01) and duration of longest acid reflux ≥ 18 minutes (AUC 0.784, CI 0.692-0.875, p<0.01).
The results of our study suggested that compared with pH-metry alone, pH-MII had significantly higher detection rate of gastroesophageal reflux disease, especially in infants. Our findings also showed that pH-MII parameters correlated significantly with the endoscopically confirmed erosive esophagitis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Research of uvological characteristics is one of the obligatory steps for
determination of general production and technological value of grapevine
varieties. Such research is particularly recommended ...for local varieties
that did not previously show sat?isfying characteristics necessary for
production of high-quality wine. Local grapevine varieties Smederevka (white
wine variety) and Zametovka (red wine variety) have mostly served for
production of low-quality wine in the past. With changes in the manner of
pro?duction in the sense of focus on high-quality wine and production of
wine with geograph?ical indications, vineyards planted with these varieties
in Serbia have mostly been grubbed up. However, due to the characteristic
and favourable terroir conditions, they have survived in the Trstenik
wine-growing district (subregion within the Tri Morave wine-growing
re?gion). With the aim of determining uvological characteristics of these
two varieties in current climate conditions that are favourable for these
high-yield varieties, this paper examines the mechanical composition of
grape bunches (bunch weight, number of berries, stem weight), mechanical
composition of berries (weight of 100 berries, weight of skin of 100
berries, weight of mesocarp of 100 berries and weight of seeds of 100
berries), as well as grape must characteristics (sugar content and total
acids in grape must) of representative genotypes of local varieties
Smederevka and Zametovka in production vineyards in the Trstenik
wine-growing district. Research results have shown that uvological
characteristics of these varieties are slightly better in comparison with
previous research carried out in other wine-growing areas, that is, in
comparison with general information from literature, which indicates the
necessity for further research of these varieties in different
agro-eco?logical conditions.
The autochthonous, i.e. local, red wine variety Prokupac is one of the most important varieties in Serbia. In the past, this variety was the leading one in the largest number of wine-growing areas of ...our country. The Prokupac variety is currently the most represented in the Tri Morave wine-growing region (Central Serbia), while the largest number of vineyards with this variety are located in the Zupa wine-growing subregion. Due to its importance as an old and traditional variety, certain researches of this variety have been initiated in recent years in wine-growing areas where Prokupac is traditionally grown. Certain scientific activities were initiated to isolate different genotypes with improved production and use value, all with the aim of clonal selection of this variety. In this paper, some characteristics and quality parameters of the more promising Prokupac genotypes that were isolated in the Zupa wine-growing subregion in the Aleksandrovac municipality are presented. More extensive research was carried out on grapes from the harvest of 2019, 2020 and 2021 with 16 selected genotypes, namely eight genotypes from the Latkovac locality and eight genotypes from the Drenca locality. In addition to laboratory analyses of sugar, acid and pH content in the grape must, the theoretical alcohol content was also calculated. Furthermore, spectrophotometric methods were used to determine colour intensity A-420, colour intensity A-520, colour intensity A-620 and total colour intensity, as well as colour tonality. The analyses showed that certain main quality parameters from the research are within the value limits as in earlier research, but that the acid content is generally more optimal for red wine varieties compared to the research of that parameter carried out in the earlier period in other wine-growing areas (Fruska Gora and Cegar wine-growing subregions). Moreover, in our research, the sugar content of the grape is higher than the established values of that parameter in the grape must from the Cegar wine-growing subregion.
Increasing profits by reducing costs during product development and its production and quality increasingare challenges that companies face every day in their operations. The aspiration of modern ...production is to achievean effect similar to those in mass production (or at least in large series production) even on extremely small series ofproducts, even on personalized products. Techno-economic analysis in modern companies is an integral part of thecompany's modern information system. This paper presents a techno-economic analysis of innovative technologiesfor the production of a wagons triangle brake, a product that is an integral part of the brake system of freight andpassenger wagons of the older generation: casting and additive technologies. Given that there are currently availabledifferent production technologies that can be applied, one of the criteria for choosing a production technology is itsprofitability. The choice of solution, whether the product will be made by casting (or welding) or additivetechnology, is mostly influenced by the size of the series. In the case of the cast part, the so-called constant costs(model, molds for cores), but variable costs are therefore lower, i.e., costs proportional to the number ofmanufactured pieces. Additive technologies that can be used to make such parts can use numerous methods, three ofwhich stand out due to their application in practice. These are stereolithography (STL), extruded material (EBM)and direct metal laser sintering (DMLS). Machine cost is the main factor for stereolithography and melt extrusion,while material cost is the main factor for laser sintering. The price of additively manufactured parts is calculatedaccording to the cost model that follows activities, where each cost is linked to a specific activity. The analysisindicates that additive technologies are not such a cheap process, especially in serial production, but they areexcellent in individual production or during rapid prototyping, and the price of the product obtained by additivetechnology is the same for each piece. Also, cast parts have high initial costs (casting molds, etc.), but castings arerelatively cheap, which leads to a drop in the total price as the series increases. Both technologies have limitations interms of the materials that can be used in casting or additive manufacturing processes. Based on the technoeconomicanalysis, it can be concluded, also, that certain activities require the engagement of other companies thatshould be entrusted with certain business activities or tasks - in this way, the company's resources are saved andemployed on other more expedient activities that will bring greater benefits, and the system work is not disturbed ordisturbed. The advantage of casting technology over additive technologies is already profitable for series over 42pieces, and compared to forging, the casting of this part of the product is 2.5 times cheaper.
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