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51.
Mechanisms of premature fracture in modular neck stems made of CoCrMo/Ti6Al4V and Ti6Al4V/Ti6Al4V alloy
Drago Dolinar, Miro Gorenšek, Klemen Avsec, Barbara Šetina, Matej Hočevar, Matjaž Godec, Borut Žužek, Mojca Debeljak, Monika Jenko, John T. Grant, Boštjan Kocjančič, 2023, original scientific article

Abstract: In this paper, we present the mechanisms of premature fracture of modular neck stems in two case studies: (I) when the neck and stem are both made of the same Ti6Al4V alloy, and (II) when the neck and stem are made from two different alloys, CoCrMo and Ti6Al4V alloy. Our study integrates two orthopedic patients who have undergone primary uncemented THA for usual indications in two orthopedic centers (Community Health Centre and University Medical Centre). Both centers are part of the national public health care system. Both surgeries were performed by two skilled orthopedic surgeons with more than 10 years of experience in THA. The survivorship of the modular neck of cast CoCrMo alloy was 24 months. The survivorship of the modular neck from Ti6Al4V alloy was 84 months. Multivariate analyses were performed to assess the differences in the fretting, corrosion, and fatigue of the two prematurely failed modular neck stems: stereo light microscopy (SLM), scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), and electron backscatter diffraction (EBSD). Patient demographic information, including sex, age, body mass index, survivorship of implants, and reason for the revision, was collected from medical records. We found that fretting and fatigue occurred on both neck-stem retrievals due to additional galvanic corrosion, but the CoCrMo/Ti6Al4V alloy system suffered more corrosion due to additional galvanic corrosion and fractured earlier than the Ti6Al4V/Ti6Al4V metal alloy system. Both metallic alloy systems used in this application are known to be highly corrosion-resistant, but the bio-tribo-corrosion processes need to be understood in detail and characterized so that appropriate improvements in design and materials can be made.
Keywords: total hip arthroplasty, modular neck, Ti6Al4V alloy, CoCrMo alloy, corrosion
Published in DiRROS: 07.02.2024; Views: 216; Downloads: 122
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52.
An outbreak of Verticillium dahliae on sycamore maple in a forest stand in Slovenia
Ana Brglez, Zina Devetak, Nikica Ogris, Sebastjan Radišek, Barbara Piškur, 2024, original scientific article

Abstract: Verticillium dahliae Kleb., the causal agent of Verticillium wilts, is a devastating plant disease affecting many plant species. Fungus V. dahliae was detected in a partially artificially established Acer pseudoplatanus L. forest stand in central Slovenia. This finding incited further study about the risk of different sources of V. dahliae isolates for maples in forests and the pathogenicity of three V. dahliae isolates of different origins was tested on saplings of A. pseudoplatanus, A. platanoides L., and A. campestre L. The inoculated saplings exhibited disease symptoms, i.e., leaf necrosis and wilting. At the end of the pathogenicity test, typical xylem browning was visible on the cross-sections, and the pathogen was successfully re-isolated. The isolates showed significant differences in their pathogenicity to specific maple hosts, with the agricultural isolate (originated from bell pepper) being the most aggressive on all three maple species. The disease severity index (DSI) and relative area under the disease progress curve (rAUDPC), as well as the success of re-isolation, indicate that A. platanoides is the most susceptible to inoculation with V. dahliae. In addition, significant differences in sapling biomass were observed between treated and control plants. These results suggest that maples in forest stands are threatened by V. dahliae, and biosecurity measures should be considered and implemented in forest management to reduce the transmission and potential spread of the pathogen.
Keywords: Verticillium wilt, Acer spp., pathogenicity test, Disease severity index, DSI, Area under the disease progress curve, AUDPC, biosecurity
Published in DiRROS: 07.02.2024; Views: 180; Downloads: 82
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The influence of storage conditions and DNA extraction protocol on the results of molecular analysis of the European spruce bark beetle (Ips typographus L.)
Zina Devetak, Andreja Kavčič, Maarten De Groot, Barbara Piškur, 2023, original scientific article

Abstract: One of the key steps of the molecular identification of bark beetles is obtaining a sufficient quantity of high-quality DNA extract. In this study, we investigated the influence of different storage procedures for Ips typographus (L.) specimens and various DNA extraction protocols on the quantity and quality of DNA intended for use in molecular diagnostics. Adult beetles were frozen at -20 °C, either dry or in ethanol. We tested four different protocols for DNA extraction. We compared the quantity of extracted DNA and assessed its quality with PCR and Sanger sequencing. Different storage protocols had no significant effect on the quantity of DNA extracted. However, freezing specimens in ethanol provided higher-quality DNA for molecular applications. Only two of the extraction protocols produced sequenceable amplicons, and the difference in the amount of extracted DNA between them was not significant. We propose the optimal combination of storing specimens in ethanol at -20°C and using the Nucleospin Insect DNA extraction kit from Macherey Nagel, enabling a timeefficient identification process.
Keywords: early detection, specimen storage, total DNA extraction, PCR, polymerase chain reaction, Sanger sequencing, molecular diagnostics
Published in DiRROS: 02.02.2024; Views: 419; Downloads: 125
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The influence of different fibres quantity on mechanical and microstructural properties of alkali-activated foams
Katja Traven, Mark Češnovar, Barbara Horvat, Vilma Ducman, 2022, published scientific conference contribution

Abstract: Alkali activated foams (AAFs) were produced using electric arc furnace steel slag (EAF) and ladle furnace basic slag (LS), obtained from two metallurgical companies in Slovenia. They were activated with a mixture of sodium water glass (Na2SiO3) and solid NaOH and foamed with hydrogen peroxide (H2O2). Pores were stabilized with the addition of Triton as a surfactant. Four types of fibres were added to the studied mixture (polypropylene (PP), polyvinyl-alcohol (PVA), basalt (B), and glass wool (GW)) in five different quantities: 0.5, 1.0, 1.25, 1.5 and 2.0 vol % in order to additionally stabilize the structure and thus improve its mechanical properties. The results of mechanical properties showed, that compressive strength was increased in all 20 specimens, partially due to the increased density as well as to the fibre addition. Flexural strength on the other hand was the most improved in the samples where PP and PVA fibres were added. The samples with the addition of B and GW fibres on the other hand showed only small or no improvement in flexural strength in comparison to the referenced sample. Additionally, the microstructure of used fibres and selected foams was also investigated by the means of SEM analysis.
Keywords: fibers, alkali activated foams, properties
Published in DiRROS: 31.01.2024; Views: 146; Downloads: 58
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59.
Cysteine proteinase inhibitors stefin A and stefin B in operable carcinoma of the head and neck : Inhibitorji cisteinskih proteinaz stefin A in stefin B pri operabilnem karcinomu glave in vratu
Primož Strojan, Marjan Budihna, Alojz Šmid, Branka Svetic, Ivan Vrhovec, Janko Kos, Janez Škrk, 2002, original scientific article

Abstract: Purpose. To evaluate the significance of cysteine proteinase inhibitors stefins (Stefs) A and B for a treatment decision and prognosis in operable squamous cell carcinoma of the head and neck (SCCHN). Patients and methods. Stefs A and B concentrations were determined immunobiochemically using ELISAs in cytosols prepared from the tumor and adjacent normal mucosa from 91 patients with operable SCCHN. The median follow-up period of patients alive atthe close-out date was 5.8 years (range, 5-9.3 years). Results. Stef A concentrations were significantly higher in tumor compared to normal mucosa (FM.05). When a subgroup with clinically palpable nodes) at presentation was taken into consideration (n=57), a significant difference in Stef A (P=0.03) and Stef B (P=0.02) concentrations between those with negative and positive necks, as determined on histopathological examination, was observed. On the univariate survival analysis, higher Stefsć concentrations turned to be prognostically advantageous. Stef A proved its independent prognostic significance also on multivariate setting. Conclusions. With the capability todifferentiate between the pN0- and pN+-stages of the disease in the patientsoriginally presented as node-positive, Stefs A and B could be useful markers when deciding on the extent of neck surgery. In addition, both Stefs proved to be reliable prognosticators for survival in patients with operable SCCHN.
Published in DiRROS: 31.01.2024; Views: 139; Downloads: 34
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60.
A brief overview of the tumor vaccines through the last decade
Srdjan Novaković, Barbara Jezeršek Novaković, 2002, review article

Abstract: How to destroy cancer cells without damaging the normal cells? How to make conventional methods of systemic cancer treatment that predominantly comprise cytotoxic drugs more selective and prevent the development of drug resistance?There is an abundance of such guestions that do not have simple answers. If, a few years ago, unselective cytotoxic drugs were the method of choice for the treatment of cancer, in the last 25 years we are witnessing therapid transition of immunotherapy from the laboratories to the clinics. Among the most attractive and promising immunotherapies for cancer, a special place is reserved for tumor vaccines. Exploiting the latest knowledge in immunology, tumor physiology, as well as in molecular biology, many outstanding approaches for the creation of tumor vaccines have been developed.With no intention to be comprehensive, in the present article some of those approaches are reviewed.
Published in DiRROS: 31.01.2024; Views: 147; Downloads: 33
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