Прегледај по Аутор "Zdravković, Nataša"
Сада се приказује 1 - 7 од 7
Резултати по страници
Опције сортирања
- СтавкаColorectal carcinoma: evaluation of systemic values of interleukin-1 and interleukin-33 in patients with and without thrombocytosis(Ministry of Defance, Serbia, 2021) Jocić, Miodrag; Gajović, Nevena; Jurišević, Milena; Jovanović, Marina; Zdravković, Nataša; Arsenijević, Nebojša; Vuković Dejanović, Vesna; Marić, Veljko; Milev, Boško; Jovanović, MilanBackground/Aim. Reactive thrombocytosis, as a parane-oplastic syndrome, is often observed in cancer patients. A variety of tumor-related humoral factors and cytokines con-tribute to tumor-stimulated thrombopoiesis. However, the exact role of these cytokines in the pathogenesis of throm-bocytosis remains unclear. The aim of this study was to ana-lyze systemic values of cytokines and clinical-pathological characteristics in colorectal carcinoma (CRC) patients with and without thrombocytosis. Methods. Fifty nine CRC pa-tients were involved in this study and divided into two groups according to the number of platelets. We recorded and analyzed the data about: age, gender, size of the cancer, localization, metastasis, vascular or lymph vessel invasion, nuclear grade, histological differentiation rate, tumor, no-dus, metastasis (TNM) stage and concentration of cytokines [interleukin (IL)-1, IL-33, IL-12, IL-17 and interferon (IFN)-γ] in both groups. Results. CRC patients with thrombocytosis had significantly higher nuclear grade of the cancer (p = 0.002); higher percentage of detectable metastat-ic lesions in the liver (p = 0.002), lung (p = 0.001), peritoneal carcinomatosis (p = 0.001), detectable invasion of blood (p= 0.012) and lymph vessels (p = 0.010). Concentrations of tumor markers [alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA) and cancer antigen 19-9 (CA19-9)] and se-rum values of IL-1 and IL-33 were significantly higher in CRC patients with thrombocytosis. IL-1/IL-12 (p = 0.016), IL-1/IFN-γ (p = 0.007), IL-1/IL-17 (p = 0.006), IL-33/IL-12 (p = 0.001), IL-33/IFN-γ (p = 0.001), IL-33/IL-17 (p = 0.002), and IL-33/IL-1 (p = 0.006) ratios were significantly higher in CRC patients with thrombocytosis in comparison to CRC patients without thrombocytosis. Analysis of Re-ceiver Operating Characteristic (ROC) curves showed that values of IL-1 [area under curve (AUC) = 0.718; 95% con-fidence interval (CI): 0.567–0.868; sensitivity 69.2%, speci-ficity 62.9%] and IL-33 (AUC = 0.763; 95% CI: 0.614–0.911; sensitivity 84.6%, specificity 65.7%)], could be serve as possible markers for paraneoplastic thrombocytosis in CRC patients. Conclusion. IL-1 and IL-33 significantly correlated to high thrombocyte number in patients with more aggressive CRC.
- СтавкаComparison between Mechanical Properties and Joint Performance of AA 2024-T351 Aluminum Alloy Welded by Friction Stir Welding, Metal Inert Gas and Tungsten Inert Gas Processes(MDPI, 2024-07-05) Milčić, Miodrag; Klobčar, Damjan; Milčić, Dragan; Zdravković, Nataša; Ðurić, Aleksija; Vuherer, TomažThe aim of this work is to study joining Al 2024-T3 alloy plates with different welding procedures. Aluminum alloy AA 2024-T351 is especially used in the aerospace industry. Aluminum plates are welded by the TIG and MIG fusion welding process, as well as by the solid-state welding process, friction stir welding (FSW), which has recently become very important in aluminum and alloy welding. For welding AA2024-T35 with MIG and TIG fusion processes, the filler material ER 4043—AlSi5 was chosen because of reduced cracking. Different methods were used to evaluate the quality of the produced joints, including macro- and microstructure evaluation, in addition to hardness and tensile tests. The ultimate tensile strength (UTS) of the FSW sample was found to be 80% higher than that of MIG and TIG samples. The average hardness value of the weld zone of metal for the MIG- and TIG-produced AA2024-T3511 butt joints showed a significant decrease compared to the hardness of the base metal AA2024-T351 by 50%, while for FSW joints, in the nugget zone, the hardness is about 10% lower relative to the base metal AA2024-T3511.
- СтавкаComparison between Mechanical Properties and Joint Performance of AA 2024-T351 Aluminum AlloyWelded by Friction Stir Welding, Metal Inert Gas and Tungsten Inert Gas Processes(MDPI, 2024) Milčić, Miodrag; Klobčar, Damjan; Milčić, Dragan; Zdravković, Nataša; Ðurić, Aleksija; Vuherer, TomažThe aim of this work is to study joining Al 2024-T3 alloy plates with different welding procedures. Aluminum alloy AA 2024-T351 is especially used in the aerospace industry. Aluminum plates are welded by the TIG and MIG fusion welding process, as well as by the solid-state welding process, friction stir welding (FSW), which has recently become very important in aluminum and alloy welding. For welding AA2024-T35 with MIG and TIG fusion processes, the filler material ER 4043—AlSi5 was chosen because of reduced cracking. Different methods were used to evaluate the quality of the produced joints, including macro- and microstructure evaluation, in addition to hardness and tensile tests. The ultimate tensile strength (UTS) of the FSW sample was found to be 80% higher than that of MIG and TIG samples. The average hardness value of the weld zone of metal for the MIG- and TIG-produced AA2024-T3511 butt joints showed a significant decrease compared to the hardness of the base metal AA2024-T351 by 50%, while for FSW joints, in the nugget zone, the hardness is about 10% lower relative to the base metal AA2024-T3511.
- СтавкаFecal galectin-1 as a potential marker for colorectal cancer and disease severity(Ministry of Defance, Serbia, 2019) Jovanović, Milan; Gajović, Nevena; Zdravković, Nataša; Jovanović, Marina; Jurišević, Milena; Vojvodić, Danilo; Mirković, Darko; Milev, Boško; Marić, Veljko; Arsenijević, NebojšaBackground/Aim. Colorectal cancer (CRC) represents one of the most common cancers worldwide. CRC is frequently diagnosed at advanced stages with poor prognosis, indicating the need for new diagnostic and prognostic markers. The aim of this study was to determine systemic and fecal values of galectin- 1 (gal-1) and ratios between gal-1 and proinflammatory cytokines: tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interferon gamma (IFN-γ), in the patients with CRC and the relationship with clinicopathological aspects of the disease. Methods. The blood samples and feces liquid fraction of 58 patients with CRC were analyzed. The serum and fecal levels of TNF-α, IL-1β and IFN-γ and gal-1 were measured using sensitive enzyme-linked immunosorbent assay (ELISA) kits. Results. The fecal level of gal-1 was increased in the CRC patients with higher nuclear grade and poor tumor tissue differentiation. The gal-1/TNF-α ratio in the serum and feces had a higher trend in the patients with the advanced tumor-nodemetastasis (TNM) stage as well as the detectable lymphatic and blood vessel invasion. The gal-1/TNF-α and gal-1/IFN-γ ratios were increased in the serum of patients with presence of lung/liver metastasis or peritoneal carcinomatosis, while the enhanced gal-1/IL-1 ratio was detected only in the serum of patients with lung metastasis. A positive correlation between the gal-1 value in feces and histological differentiation of tumor and biomarkers alpha-fetoprotein (AFP) and cancer antigen- 19-9 (CA 19-9), respectively, was also observed. The fecal values of gal-1 higher than 13,708.29 pg/g presented a highly sensitive and specific marker for histological differentiation of tumor tissue. Conclusion. We believe that the predomination of gal-1 over pro-inflammatory cytokines TNF-α, IL-1β and IFN- γ in the patients with advanced and progressive CRC may implicate on an immunomodulatory role of gal-1 in the limiting ongoing proinflammatory processes. The fecal values of gal-1 can be used as a valuable marker for the severity of CRC.
- СтавкаFecal sST2 correlates with the disease severity of ulcerative colitis(Ministry of Defance, Serbia, 2019) Jovanović, Marina; Gajović, Nevena; Jurišević, Milena; Simović Marković, Bojana; Marić, Veljko; Jovanović, Milan; Arsenijević, Nebojša; Zdravković, NatašaBackground/Aim. Ulcerative colitis (UC) is a chronic, relapsing inflammatory disease affecting the distal colon and rectum with complex pathogenesis and diagnosis, indicating the need for new diagnostic and prognostic markers. The aim of this study was to determine the fecal values of TNF- α, IL-17, IL-10 and soluble protein ST2 (sST2) in the patients with UC and their relationship with clinicopathological aspects. Methods. The samples of stool of 80 patients with UC were analyzed. Concentrations of TNF-α, IL-17, IL-10 and sST2 were measured by ELISA. Results. Concentrations of TNF-α, IL-17 and sST2 were significantly increased in the feces of patients with the higher endoscopic, clinical and total Mayo score, as well as in the patients with an intense crypt destruction, erosion of the mucous membranes, architectural changes, neutrophil infiltration and eosinophil infiltration. The local value of anti-inflammatory cytokine IL-10 in liquid fraction of feces was increased in the patients with an advanced endoscopic stage of UC. The moderate positive correlation between the fecal sST2/IL-17 and the clinical and histological parameters of disease severity and also the strong correlation between sST2 and IL-17 was also observed in the feces of patients with UC. The analysis of receiver operating characteristic (ROC) curves showed that the optimal cut-off value for sST2 of 624.0 pg/g allows the discrimination of clinical stages of UC. Conclusion. The increased fecal value of sST2 in the UC patients with a higher endoscopic, clinical and histological stage of disease may be considered as a sign of the disease severity. The fecal values of sST2 can be used as a valuable marker for UC severity
- СтавкаInfluence of Surface Preparation of Aluminum Alloy AW-5754 and Stainless Steel X5CRNI18-10 on the Properties of Bonded Joints(MDPI, 2024) Zdravković, Nataša; Klobčar, Damjan; Milčić, Dragan; Zupančić, Matevž; Žužek, Borut; Milčić, Miodrag; Ðurić, AleksijaAdhesive bonding has proven to be a reliable method of joining materials, and the development of new adhesives has made it possible to use bonding in a variety of applications. This article addresses the challenges of bonding metals such as the aluminum alloy EN AW-5754 and the stainless steel X5CrNi18-10. In this study, the effects of laser cleaning and texturing on the surface properties and strength of two bonded joints were investigated and compared with mechanical preparation (hand sanding with Scotch-Brite and P180 sandpaper). The bonded joints were tested with three different epoxy adhesives. During the tests, the adhesion properties of the bonded surface were determined by measuring the contact angle and assessing the wettability, the surface roughness parameters for the different surface preparations, and the mechanical properties (tensile lap-shear strength). Based on the strength test results, it was found that bonded joints made of stainless steel had 16% to 40% higher strength than aluminum alloys when using the same adhesive and surface preparation. Laser cleaning resulted in maximum shear strength of the aluminum alloy bond, while the most suitable surface preparation for both materials was preparation with P180 sandpaper for all adhesives.
- СтавкаInfluence of Surface Preparation of Aluminum Alloy AW-5754 and Stainless Steel X5CRNI18-10 on the Properties of Bonded Joints(MDPI, 2024) Zdravković, Nataša; Klobčar, Damjan; Milčić, Dragan; Zupančić, Matevž; Žužek, Borut; Milčić, Miodrag; Ðurić, AleksijaAdhesive bonding has proven to be a reliable method of joining materials, and the development of new adhesives has made it possible to use bonding in a variety of applications. This article addresses the challenges of bonding metals such as the aluminum alloy EN AW-5754 and the stainless steel X5CrNi18-10. In this study, the effects of laser cleaning and texturing on the surface properties and strength of two bonded joints were investigated and compared with mechanical preparation (hand sanding with Scotch-Brite and P180 sandpaper). The bonded joints were tested with three different epoxy adhesives. During the tests, the adhesion properties of the bonded surface were determined by measuring the contact angle and assessing the wettability, the surface roughness parameters for the different surface preparations, and the mechanical properties (tensile lap-shear strength). Based on the strength test results, it was found that bonded joints made of stainless steel had 16% to 40% higher strength than aluminum alloys when using the same adhesive and surface preparation. Laser cleaning resulted in maximum shear strength of the aluminum alloy bond, while the most suitable surface preparation for both materials was preparation with P180 sandpaper for all adhesives.