21. |
22. Postoperative radiochemotherapy for gastric adenocarcinoma : long term resultsIrena Oblak, Franc Anderluh, Vaneja Velenik, 2009, izvirni znanstveni članek Povzetek: Background. To analyze the efficacy of postoperative radiochemotherapy with 5-florouracil (5-FU) and leucovorin (LV) applied in the patients with gastric carcinoma treated in a single institution. Patients and methods. Between 2001 and 2004, 123 patients with resected gastric adenocarcinoma were treated with postoperative concomitant radiochemotherapy with 5-FU and LV. The adjuvant treatment consisted of five cycles of chemotherapy with 5-FU (425mg/m2 IV) andLV (20 mg/m2 IV) and concomitant radiotherapy with the total dose of 45 Gy.Results. The treatment was completed according to the protocol in 82% of patients. The frequency and severity of early toxic effects induced by radiochemotherapy were manageable. Median follow-up time of 56 survivors was 64.5 months (range: 51.7-96.4 months). The 5-year locoregional control (LRC), diseasefree survival (DFS), disease-specific survival (DSS) and overall survival (OS) were 81%, 48.3%, 50.4%, and 48.4%, respectively. The multivariate analysis showed that the tumor involvement of cardia and low intensity of chemotherapy were independent adverse prognostic factors for DSS and OS. More advanced pT-stage and tumors with diffuse growth type according to Lauren were identified as negative independent prognostic factor for OS. They were also on the threshold of statistical significance for DSS. Conclusions. Postoperative radiochemotherapy for gastric carcinoma has acceptable toxicity, and is effective particularly in regard to LRC. High incidence of distant metastases calls for more effective systemic regimens.
Objavljeno v DiRROS: 08.03.2024; Ogledov: 92; Prenosov: 28
 Celotno besedilo (94,49 KB) |
23. Relevance of cold-rolling technology for the texture and anisotropy of EN AW-8011A aluminum alloysJakob Kraner, Kyung Il Kim, Bonghwan Kim, Shae K. Kim, Irena Paulin, 2023, izvirni znanstveni članek Ključne besede: aluminium alloys, cold rolling, SEM-EBSD, textures, anisotropy
Objavljeno v DiRROS: 08.03.2024; Ogledov: 125; Prenosov: 60
Celotno besedilo (2,04 MB)
Gradivo ima več datotek! Več... |
24. |
25. High temperature oxidation of EN AW 7075 aluminium alloyNejc Velikajne, Tilen Balaško, Jaka Burja, Matjaž Godec, Irena Paulin, 2024, objavljeni znanstveni prispevek na konferenci Povzetek: Aluminium alloys are highly valued for their exceptional strength-to-weight ratio, making them a preferred choice in structural applications. Among these alloys, EN AW 7075 stands out for its superior mechanical properties, finding widespread use in industries such as aerospace, mechanical engineering, and sports equipment. This study investigates the high-temperature oxidation behavior of EN AW 7075 alloy. The gathered results can provide valuable insights into the behavior of the mentioned alloy during the selective laser melting (SLM) process. These results can contribute to a better understanding of how the alloy responds to specific conditions and parameters. SLM is an additive manufacturing technique. The process involves the sequential steps of preheating, melting, and rapid cooling of metal powder. To minimize the influence of oxygen, the build chamber is filled with inert gas. A protective argon atmosphere is continuously maintained. However, despite these precautions, oxidation can still occur, leading to potential issues in the final product. Hence, we examined the oxidation kinetics of the EN AW 7075 alloy in an oxygen atmosphere in the temperature range of 300-500 °C. The findings of this investigation significantly contribute to an understanding of the behavior of the alloy during high-temperature oxidation, particularly for ongoing studies focused on processing Al-Zn-Mg-Cu alloys using the selective laser melting technique. Thermogravimetry was employed to analyze the oxidizing behavior, with three samples subjected to a 6-hour exposure in an oxidizing atmosphere at temperatures of 300, 400, and 500 °C. Surprisingly, no oxidation occurred, as indicated by the negligible and negative changes in mass observed across all samples.
Ključne besede: EN AW 7075, high-temperature oxidation, oxide film, selective laser melting
Objavljeno v DiRROS: 28.02.2024; Ogledov: 168; Prenosov: 70
Celotno besedilo (897,18 KB)
Gradivo ima več datotek! Več... |
26. Effect of heat treatment on thermal conductivity of additively manufactured AISI H13 tool steelSamo Tome, Blaž Karpe, Irena Paulin, Matjaž Godec, 2024, objavljeni znanstveni prispevek na konferenci Povzetek: AISI H13 is commonly used for tooling, where higher wear resistance, thermal fatigue resistance, or hot toughness is required. Such examples include forging dies, plastic molds, hot shear blades, high-pressure die casting, and extrusion dies. Thus, thermal conductivity is one of the most important factors for hot work tools. Typically, the work cycle of a hot work tool designed for forging consists of four main phases: the forging stroke, with which the die imparts its shape onto the part, a brief pause while the die is reset to its original position, a lubrication phase, and a post lubrication dwell phase. During the forging phase, a significant amount of heat is transferred to the die while it is in contact with the part. This heat must then be dispelled for the part to return to a working temperature. While somewhat different, other hot work processes mentioned above are similar in that the hot work tool gets heated to a high temperature due to the contact with the object of deformation. The process of additive manufacturing (AM) promises better, more efficient tool production with features like conforming cooling channels, which would reduce the thermal fatigue of tools, prolonging tool life. However, the powder bed fusion (PBF) method creates a columnar microstructure, which has a detrimental effect on the thermal conductivity of H13 tool steel. Our investigation focused on the beneficial effect of heat treatment, specifically annealing at different temperatures, on the thermal conductivity of AM-produced H13 parts.
Ključne besede: SLM, thermal conductivity, tool steel, heat treatment
Objavljeno v DiRROS: 28.02.2024; Ogledov: 129; Prenosov: 73
Celotno besedilo (655,96 KB)
Gradivo ima več datotek! Več... |
27. Extreme environments simplify reassembly of communities of arbuscular mycorrhizal fungiNataša Šibanc, Dave R. Clark, Thorunn Helgason, Alex J. Dumbrell, Irena Maček, 2024, izvirni znanstveni članek Povzetek: The ecological impacts of long-term (press) disturbance on mechanisms regulating the relative abundance (i.e., commonness or rarity) and temporal dynamics of species within a community remain largely unknown. This is particularly true for the functionally important arbuscular mycorrhizal (AM) fungi; obligate plant-root endosymbionts that colonize more than two-thirds of terrestrial plant species. Here, we use high-resolution amplicon sequencing to examine how AM fungal communities in a specific extreme ecosystem—mofettes or natural CO2 springs caused by geological CO2 exhalations—are affected by long-term stress. We found that in mofettes, specific and temporally stable communities form as a subset of the local metacommunity. These communities are less diverse and dominated by adapted, “stress tolerant” taxa. Those taxa are rare in control locations and more benign environments worldwide, but show a stable temporal pattern in the extreme sites, consistently dominating the communities in grassland mofettes. This pattern of lower diversity and high dominance of specific taxa has been confirmed as relatively stable over several sampling years and is independently observed across multiple geographic locations (mofettes in different countries). This study implies that the response of soil microbial community composition to long-term stress is relatively predictable, which can also reflect the community response to other anthropogenic stressors (e.g., heavy metal pollution or land use change). Moreover, as AM fungi are functionally differentiated, with different taxa providing different benefits to host plants, changes in community structure in response to long-term environmental change have the potential to impact terrestrial plant communities and their productivity
Ključne besede: arbuscular mycorrhiza, elevated CO2, long-term experiments, soil biodiversity, soil hypoxia, next-generation sequencing, NGS
Objavljeno v DiRROS: 28.02.2024; Ogledov: 152; Prenosov: 71
Celotno besedilo (1,45 MB)
Gradivo ima več datotek! Več... |
28. Characterization of hFOB 1.19 cell line for studying Zn-based degradable metallic biomaterialsEva Jablonská, Lucie Mrázková, Jiří Kubásek, Dalibor Vojtěch, Irena Paulin, Tomáš Ruml, Jan Lipov, 2024, izvirni znanstveni članek Povzetek: In vitro testing is the first important step in the development of new biomaterials. The human fetal osteoblast cell line hFOB 1.19 is a very promising cell model; however, there are vast discrepancies in cultivation protocols, especially in the cultivation temperature and the presence of the selection reagent, geneticin (G418). We intended to use hFOB 1.19 for the testing of Zn-based degradable metallic materials. However, the sensitivity of hFOB 1.19 to zinc ions has not yet been studied. Therefore, we compared the toxicity of zinc towards hFOB 1.19 under different conditions and compared it with that of the L929 mouse fibroblast cell line. We also tested the cytotoxicity of three types of Zn-based biomaterials in two types of media. The presence of G418 used as a selection reagent decreased the sensitivity of hFOB 1.19 to Zn2+. hFOB 1.19 cell line was more sensitive to Zn2+ at elevated (restrictive) temperatures. hFOB 1.19 cell line was less sensitive to Zn2+ than L929 cell line (both as ZnCl2 and extracts of alloys). Therefore, the appropriate cultivation conditions of hFOB 1.19 during biomaterial testing should be chosen with caution.
Ključne besede: zinc degradable materials, in vitro cytotoxicity testing, hFOB 1.19 osteoblasts
Objavljeno v DiRROS: 28.02.2024; Ogledov: 142; Prenosov: 58
Celotno besedilo (1,81 MB)
Gradivo ima več datotek! Več... |
29. |
30. |
