1801. CA19-9 serum levels predict micrometastases in patients with gastric cancerTomaž Jagrič, Stojan Potrč, Katarina Miš, Mojca Plankl, Tomaž Marš, 2016, izvirni znanstveni članek Povzetek: Background. We explored the prognostic value of the up-regulated carbohydrate antigen (CA19-9) in node-negative patients with gastric cancer as a surrogate marker for micrometastases. Patients and methods. Micrometastases were determined using reverse transcription quantitative polymerase chain reaction (RT-qPCR) for a subgroup of 30 node-negative patients. This group was used to determine the cut-off for preoperative CA19-9 serum levels as a surrogate marker for micrometastases. Then 187 node-negative T1 to T4 patients were selected to validate the predictive value of this CA19-9 threshold. Results. Patients with micrometastases had significantly higher preoperative CA19-9 serum levels compared to patients without micrometastases (p = 0.046). CA19-9 serum levels were significantly correlated with tumour site, tumour diameter, and perineural invasion. Although not reaching significance, subgroup analysis showed better five-year survival rates for patients with CA19-9 serum levels below the threshold, compared to patients with CA19-9 serum levels above the cut-off. The cumulative survival for T2 to T4 node-negative patients was significantly better with CA19-9 serum levels below the cut-off (p = 0.04). Conclusions. Preoperative CA19-9 serum levels can be used to predict higher risk for haematogenous spread and micrometastases in node-negative patients. However, CA19-9 serum levels lack the necessary sensitivity and specificity to reliably predict micrometastases.
Ključne besede: gastric cancer, micrometastases, CA19-9, rak (medicina), želodec, metastaze, diagnostika, antigeni, tumorski označevalci
Objavljeno v DiRROS: 09.05.2024; Ogledov: 401; Prenosov: 275
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1802. Pancreaticoduodenectomy for ductal adenocarcinoma of the pancreatic head with venous resectionVojko Flis, Stojan Potrč, Nina Kobilica, Arpad Ivanecz, 2016, izvirni znanstveni članek Povzetek: Background. Recent reports have shown that patients with vascular tumour invasion who undergo concurrent vascular resection can achieve long-term survival rates equivalent to those without vascular involvement requiring pancreaticoduodenectomy alone. There is no consensus about which patients benefit from the portal-superior mesenteric vein resection and there is no consensus about the best surgical technique of vessel reconstruction (resection with or without graft reconstruction). As published series are small the aim of this study was to evaluate our experience in pancreatectomies with en bloc vascular resection and reconstruction of vessels. Methods. Review of database at University Clinical Centre Maribor identified 133 patients (average age 65.4 +/- 8.6 years, 69 female patients) who underwent pancreatoduodenectomy between January 2006 and August 2014. Clinical data, operative results, pathological findings and postoperative outcomes were collected prospectively and analyzed. Current literature and our experience in pancreatectomies with en bloc vascular resection and reconstruction of portal vein are reviewed. Results. Twenty-two patients out of 133 (16.5 %) had portal vein-superior mesenteric vein resection and portal vein reconstruction (PVR) during pancreaticoduodenectomy. In fourteen patients portal vein was reconstructed without the use of synthetic vascular graft. In these series two types of venous reconstruction were performed. When tumour involvement was limited to the superior mesenteric vein (SPV) or portal vein (PV) such that the splenic vein could be preserved, and vessels could be approximated without tension a primary end-to-end anastomosis was performed. When tumour involved the SMV-splenic vein confluence, splenic vein ligation was necessary. In the remaining eight procedures interposition graft was needed. Dacron grafts with 10 mm diameter were used. There was no infection after dacron grafting. One patient had portal vein thrombosis after surgery: it was thrombosis after primary reconstruction. There were no thromboses in patients with synthetic graft interposition. There were no significant differences in postoperative morbidity, mortality or grades of complication between groups of patients with or without a PVR. Median survival time in months was in a group with vein resection 16.13 months and in a group without vein resection 15.17 months. Five year survival in the group without vein resection was 19.5%. Comparison of survival curves showed equal hazard rates with log-rank p = 0.090. Conclusions. Survival of patients with pancreatic cancer who undergo an R0 resection with reconstruction was comparable to those who have a standard pancreaticoduodenectomy with no added mortality or morbidity. Synthetic graft appeared to be an effective and safe option as an interposition graft for portomesenteric venous reconstruction after pancreaticoduodenectomy.
Objavljeno v DiRROS: 09.05.2024; Ogledov: 339; Prenosov: 211
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1803. Imaging of human glioblastoma cells and their interactions with mesenchymal stem cells in the zebrafish (Danio rerio) embryonic brainMiloš Vittori, Barbara Breznik, Tajda Gredar, Katja Hrovat, Lilijana Bizjak-Mali, Tamara Lah Turnšek, 2016, izvirni znanstveni članek Ključne besede: brain tumors, tumor microenvironment, animal models, xenotransplantation
Objavljeno v DiRROS: 09.05.2024; Ogledov: 367; Prenosov: 543
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1804. Non-contrast computed tomography in the diagnosis of cerebral venous sinus thrombosisJernej Avsenik, Janja Pretnar-Oblak, Katarina Šurlan Popović, 2016, izvirni znanstveni članek Povzetek: Due to the diversity of underlying factors and the absence of a uniform treatment approach, diagnosis and management of patients with cerebral venous sinus thrombosis (CVST) remain a challenging task.1 CVST represents 0.5% to 1% of all strokes and affects approximately 5 patients per million every year, but has a higher frequency among younger patients. Typical acquired risk factors include recent surgery, trauma, pregnancy, postpartum state, antiphospholipid syndrome, cancer and use of oral contraceptives. Cases of inherited thrombophilia include Antithrombin III, Protein C and Protein S deficiency, factor V Leiden positivity, prothrombin gene mutation and hyperhomocisteinemia. Infection of parameningeal spaces (ears, paranasal sinuses, oral cavity, face and neck) is common cause of CVST in pediatric population but rare in adults. The symptoms of CVST are not specific. The most common complaint is headache which occurs in up to 90% of patients. Additionally, abnormal vision, any of the symptoms of stroke and seizures have been described. In the past D-dimer levels appeared to be of value as an initial screening test. A study in 2004 evaluated the sensitivity of D-dimer to be 97.1% and specificity 99.1%.8 However, later studies showed that up to 10% of patients with CVST have a normal D-dimer. As it is fast, affordable and widely available, non-contrast computed tomography (NCCT) is the most frequently performed imaging study for evaluation of patients with new headache, focal neurological abnormalities, seizure, or change in mental status. A typical imaging finding in patients with CVST is direct visualization of a hyperattenuating thrombus in the occluded sinus (dense sinus sign). Occasionally, NCCT may only show indirect signs of thrombosis, including diffuse brain edema and parenchymal hemorrhage. Sensitivity of NCCT in the diagnosis of CVST was previously considered rather poor. However, using modern multidetector row CT scanners, recent studies report higher sensitivity and specificity values. In addition, Buyck et al. suggest measurement of the venous sinus attenuation to increase the diagnostic yield of the examination. Therefore, the goal of the present study was to evaluate the diagnostic accuracy of NCCT in the diagnosis of CVST in the emergency setting
Ključne besede: cerebral venous sinus thrombosis, computed tomography, stroke, radiologija, računalniška tomografija, diagnostika, možganski venski sinusi
Objavljeno v DiRROS: 09.05.2024; Ogledov: 360; Prenosov: 264
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1805. Virtual modelling of novel applicator prototypes for cervical cancer brachytherapyPrimož Petrič, Robert Hudej, Noora Al-Hammadi, Barbara Šegedin, 2016, izvirni znanstveni članek Povzetek: Standard applicators for cervical cancer Brachytherapy (BT) do not always achieve acceptable balance between target volume and normal tissue irradiation. We aimed to develop an innovative method of Targetvolume Density Mapping (TDM) for modelling of novel applicator prototypes with optimal coverage characteristics. Patients and methods. Development of Contour-Analysis Tool 2 (CAT-2) software for TDM generation was the core priority of our task group. Main requests regarding software functionalities were formulated and guided the coding process. Software validation and accuracy check was performed using phantom objects. Concepts and terms for standardized workflow of TDM post-processing and applicator development were introduced. Results. CAT-2 enables applicator-based co-registration of Digital Imaging and Communications in Medicine (DICOM) structures from a sample of cases, generating a TDM with pooled contours in applicator-eye-view. Each TDM voxel is assigned a value, corresponding to the number of target contours encompassing that voxel. Values are converted to grey levels and transformed to DICOM image, which is transported to the treatment planning system. Iso-density contours (IDC) are generated as lines, connecting voxels with same grey levels. Residual Volume at Risk (RVR) is created for each IDC as potential volume that could contain organs at risk. Finally, standard and prototype applicators are applied on the TDM and virtual dose planning is performed. Dose volume histogram (DVH) parameters are recorded for individual IDC and RVR delineations and characteristic curves generated. Optimal applicator configuration is determined in an iterative manner based on comparison of characteristic curves, virtual implant complexities and isodose distributions. Conclusions. Using the TDM approach, virtual applicator prototypes capable of conformal coverage of any target volume, can be modelled. Further systematic assessment, including studies on clinical feasibility, safety and effectiveness are needed before routine use of novel prototypes can be considered.
Ključne besede: cervical cancer, brachytherapy, applicators, virtual modelling
Objavljeno v DiRROS: 09.05.2024; Ogledov: 410; Prenosov: 175
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1807. Exploiting image quality measure for automatic trajectory generation in robot-aided visual quality inspectionAtae Jafari-Tabrizi, Dieter P. Gruber, Andrej Gams, 2024, izvirni znanstveni članek Povzetek: Currently, the standard method of programming industrial robots is to perform it manually, which is cumbersome and time-consuming. Thus, it can be a burden for the flexibility of inspection systems when a new component with a different design needs to be inspected. Therefore, developing a way to automate the task of generating a robotic trajectory offers a substantial improvement in the field of automated manufacturing and quality inspection. This paper proposes and evaluates a methodology for automatizing the process of scanning a 3D surface for the purpose of quality inspection using only visual feedback. The paper is divided into three sub-tasks in the same general setting: (1) autonomously finding the optimal distance of the camera on the robot’s end-effector from the surface, (2) autonomously generating a trajectory to scan an unknown surface, and (3) autonomous localization and scan of a surface with a known shape, but with an unknown position. The novelty of this work lies in the application that only uses visual feedback, through the image focus measure, for determination and optimization of the motion. This reduces the complexity and the cost of such a setup. The methods developed have been tested in simulation and in real-world experiments and it was possible to obtain a precision in the optimal pose of the robot under 1 mm in translational, and 0.1° in angular directions. It took less than 50 iterations to generate a trajectory for scanning an unknown free-form surface. Finally, with less than 30 iterations during the experiments it was possible to localize the position of the surface. Overall, the results of the proposed methodologies show that they can bring substantial improvement to the task of automatic motion generation for visual quality inspection.
Ključne besede: robot learning, eobotic quality inspection, visual quality inspection
Objavljeno v DiRROS: 09.05.2024; Ogledov: 467; Prenosov: 590
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1808. Quantitative aspects of ToF-SIMS analysis of metals and alloys in a UHV, O2 and H2 atmosphereJernej Ekar, Saša Kos, Janez Kovač, 2024, izvirni znanstveni članek Ključne besede: ToF-SIMS kvantifikacija, kovine, matrični efekt, preplavljanje, atmosferski plini
Objavljeno v DiRROS: 09.05.2024; Ogledov: 428; Prenosov: 236
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1809. Response of beech and fir to different light intensities along the Carpathian and Dinaric MountainsMatjaž Čater, Pia Caroline Adamič, Eva Dařenová, 2024, izvirni znanstveni članek Povzetek: Predicting global change mitigations based on environmental variables, like temperature and water availability, although yielding insightful hypothesis still lacks the integration of environmental responses. Physiological limits should be assessed to obtain a complete representation of a species’ fundamental niche. Detailed ecophysiological studies on the response of trees along the latitudinal gradient are rare. They could shed light on the behaviour under different light intensities and other studied traits. The forests of the Dinaric Mountains and the Carpathians represent the largest contiguous forest complexes in south-eastern Europe. In uneven-aged Carpathian (8 plots) and Dinaric Mountain (11 plots) forests, net assimilation (Amax) and maximum quantum yield (Φ) were measured for beech and fir in three predefined light intensity categories according to the indirect site factor (ISF%) obtained by the analysis of hemispherical photographs in managed and old growth forests, all located above 800 m a.s.l. The measurements were carried out under fixed environmental conditions in each light category per plot for three consecutive years. Data from the last 50-year average period from the CRU TS 4.01 dataset were used for the comparison between Amax, Φ, and climate. The highest Φ for beech were observed in the central part of the Dinaric Mountains and in the south westernmost and northwesternmost part of the Carpathians for both beech and fir, while they were highest for fir in the Dinaric Mountains in the northwesternmost part of the study area. The Φ-value of beech decreased in both complexes with increasing mean annual temperature and was highest in the open landscape. For fir in the Carpathians, Φ decreased with increasing mean annual temperature, while in the Dinaric Mountains it increased with higher temperature and showed a more scattered response compared to the Carpathians. Short-term ecophysiological responses of beech and fir were consistent to long-term radial growth observations observed on same locations. The results may provide a basis and an indication of the future response of two tree species in their biogeographical range to climate change in terms of competitiveness, existence and consequently forest management decisions.
Ključne besede: silver fir, beech, light response, Carpathian Mountains, Dinaric Mountains, temperature, precipitation
Objavljeno v DiRROS: 08.05.2024; Ogledov: 459; Prenosov: 543
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1810. Building competences for researchers working towards ocean sustainabilityJerneja Penca, Andrea Barbanti, Christopher Cvitanovic, Amel Hamza-Chaffai, Ahmed Elshazly, Jean-Baptiste Jouffray, Nezha Mejjad, Melita Mokos, 2024, izvirni znanstveni članek Povzetek: The challenges of achieving just, equitable and sustainable ocean futures require a new type of transdisciplinary and action-oriented science that integrates across disciplines and knowledge systems. Scientists and researchers in academia, industry or government, who contribute to knowledge creation, innovation, and policy development for the ocean, must be empowered with a fresh set of competences. This paper maps the knowledge, skills, and attitudes required to enable such a shift. The proposed skillset serves as a foundation for the design and operationalisation of modern training for ocean sustainability and is envisaged to be used by researchers both individually and in teams. It also highlights the potential for career diversification beyond the traditional ’blue jobs’ legitimated by existing sectors. To ensure the short-term practical implementation of the competence framework, self-awareness and self-reflection are encouraged among learners and teachers, along with pragmatic actions to overcome barriers to transdisciplinarity. For long-term impact, system interventions will be necessary to improve organisations’ readiness to absorb and valorise researchers trained in this new framework. This will require re-training the current pedagogical workforce as well as reframing existing knowledge systems and incentives.
Ključne besede: sustainable blue economy, sustainability science, marine sciences, transformative research, interdisciplinary sciences
Objavljeno v DiRROS: 07.05.2024; Ogledov: 415; Prenosov: 456
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