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Povzetek: Although secondary ion mass spectrometry (SIMS) is a versatile method used in the fields of surface analysis, depth profiling and elemental and molecular mapping, it also lacks quantification capabilities. The main reason for this is the matrix effect, which influences the ionization yield of secondary ions with respect to the substrate from which the analyzed compounds originate. There are several approaches to reduce the matrix effect, and gas flooding is one of the easiest methods to apply. In this work, we have investigated the possibilities of the ToF-SIMS method for the quantification of selected metals and alloys containing these metals in different ratios by reducing the matrix effect in the presence of different atmospheres. The measurements were performed in the ultra-high vacuum (UHV) environment, H2 and O2 atmospheres. H2 flooding shows the most significant improvements compared to the UHV analysis, while O2 is also promising but has some limitations. Improvements are most evident for the transition metals Ti, Cr, Fe, Co and Ni employed in our study, while the p-block elements such as Al and Si do not change so extensively. The deviations from the true atomic ratios of selected transition metals in different alloys reach a maximum of only 46 % when analyzed in the H2 atmosphere. In contrast, these values are 66 and 228 % for the O2 atmosphere and UHV environment, respectively. Our results suggest that gas adsorption and consequent formation of a new matrix on the surface, especially in the case of hydrogen, reduces the differences between the different chemical environments and electronic structures of the surface. In this way, the quantitative aspects of the SIMS method can be improved.
Ključne besede: ToF-SIMS quantification, H2 and O2 gas flooding, matrix effect reduction, cluster secondary ions
Objavljeno v DiRROS: 15.05.2024; Ogledov: 31; Prenosov: 17
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Ključne besede: climate sensitivity
Objavljeno v DiRROS: 14.05.2024; Ogledov: 49; Prenosov: 31
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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: 53; Prenosov: 42
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Povzetek: Metastatic colorectal cancer (mCRC) is mainly a disease of elderly, however, geriatric population is underrepresented in clinical trials. Patient registries represent a tool to assess and follow treatment outcomes in this patient population. The aim of the study was with the help of the patients% register to determine the safety and efficacy of bevacizumab plus chemotherapy in elderly patients who had previously untreated metastatic colorectal cancer. Patients and methods. The registry of patients with mCRC was designed to prospectively evaluate the safety and efficacy of bevacizumab-containing chemotherapy as well as selection of patients in routine clinical practice. Patient baseline clinical characteristics, pre-specified bevacizumab-related adverse events, and efficacy data were collected, evaluated and compared according to the age categories. Results. Between January 2008 and December 2010, 210 patients with mCRC (median age 63, male 61.4%) started bevacizumab-containing therapy in the 1st line setting. Majority of the 210 patients received irinotecan-based chemotherapy (68%) as 1st line treatment and 105 patients (50%) received bevacizumab maintenance therapy. Elderly (% 70 years) patients presented 22.9% of all patients and they had worse performance status (PS 1/2, 62.4%) than patients in < 70 years group (PS 1/2, 35.8%). Difference in disease control rate was mainly due to inability to assess response in elderly group (64.6% in elderly and 77.8% in < 70 years group, p = 0.066). The median progression free survival was 10.2 (95% CI, 6.7%16.2) and 11.3 (95% CI, 10.2%12.6) months in elderly and < 70 years group, respectively (p = 0.58). The median overall survival was 18.5 (95% CI, 12.4%28.9) and 27.4 (95% CI, 22.7%31.9) months for elderly and < 70 years group, respectively (p = 0.03). Three-year survival rate was 26% and 37.6% in elderly vs. < 70 years group (p = 0.03). Overall rates of bevacizumab-related adverse events were similar in both groups: proteinuria 21/22 %, hypertension 25/19 %, haemorrhage 2/4 % and thromboembolic events 10/6 %, for elderly and < 70 years group, respectively. Conclusions. In routine clinical practice, the combination of bevacizumab and chemotherapy is effective and welltolerated regimen in elderly patients with metastatic colorectal cancer.
Ključne besede: metastatic colorectal cancer, bevacizumab, chemotherapy, elderly
Objavljeno v DiRROS: 30.04.2024; Ogledov: 96; Prenosov: 24
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Povzetek: Background. Haemangiomas of tongue are rare type of malformations. They can be treated mostly conservatively but in some cases they need more aggressive treatment with preoperative intra arterial embolization and surgical resection. Lesions of tongue that are localized superficially can also be treated with direct puncture and injection of sclerosing agent (absolute ethanol). Case report. We present a case of a 48 years old female patient, where we performed embolization of cavernous haemangioma with mixture of absolute ethanol and oil contrast. After the procedure the patient received analgetics and antioedematous therapy. After the sclerotization the planed surgery was abandoned. Control MRI examinations 6 and 12 months after the procedure showed only a small remnant of haemangioma and no signs of a larger relapse. Conclusion. In our case the direct puncture of haemangioma and sclerotherapy with ethanol proved to be a safe and effective method to achieve preoperative devascularization of the lesion. Direct puncture of the lesion is not limited by the anatomy of the vessels or vasospasm, which can occur during the intra-arterial approach.
Objavljeno v DiRROS: 23.04.2024; Ogledov: 75; Prenosov: 38
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