| 1. |
- Kokkoris, M., et al.
(författare)
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Argon ions deeply implanted in silicon studied by Rutherford/Elastic Backscattering and Grazing Incidence X-ray Fluorescence spectroscopy
- 2019
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 450, s. 144-148
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Tidskriftsartikel (refereegranskat)abstract
- Synchrotron-radiation based techniques have recently emerged as serious competitors to traditional nuclear analytical ones, not only in the characterization of various materials, but also when the depth profiling of ultra thin surface layers is concerned. The main goal of the present work was to investigate the applicability of Grazing Incidence X-Ray Fluorescence (GIXRF) and Rutherford/Elastic Backscattering Spectrometry (RBS/EBS) techniques with respect to the accurate quantitative determination of the retained doses of Ar ions deep implanted in random direction of Si [1 1 1] polished crystalline wafers. RBS/EBS measurements with protons and deuterons were taken along with GIXRF ones, the results were compared and an attempt was made to explain the occurring similarities and differences, along with the advantages and weaknesses of each applied analytical technique.
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| 2. |
- Masliukaite, I, et al.
(författare)
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Childhood cancer and hematological disorders negatively affect spermatogonial quantity at diagnosis: a retrospective study of a male fertility preservation cohort
- 2023
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Ingår i: Human reproduction (Oxford, England). - : Oxford University Press (OUP). - 1460-2350 .- 0268-1161. ; 38:3, s. 359-370
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Tidskriftsartikel (refereegranskat)abstract
- STUDY QUESTIONWhat is the impact of cancer or hematological disorders on germ cells in pediatric male patients?SUMMARY ANSWERSpermatogonial quantity is reduced in testes of prepubertal boys diagnosed with cancer or severe hematological disorder compared to healthy controls and this reduction is disease and age dependent: patients with central nervous system cancer (CNS tumors) and hematological disorders, as well as boys <7 years are the most affected.WHAT IS KNOWN ALREADYFertility preservation in pediatric male patients is considered based on the gonadotoxicity of selected treatments. Although treatment effects on germ cells have been extensively investigated, limited data are available on the effect of the disease on the prepubertal male gonad. Of the few studies investigating the effects of cancer or hematologic disorders on testicular function and germ cell quantity in prepuberty, the results are inconsistent. However, recent studies suggested impairments before the initiation of known gonadotoxic therapy. Understanding which diseases and at what age affect the germ cell pool in pediatric patients before treatment is critical to optimize strategies and counseling for fertility preservation.STUDY DESIGN, SIZE, DURATIONThis multicenter retrospective cohort study included 101 boys aged <14 years with extra-cerebral cancer (solid tumors), CNS tumors, leukemia/lymphoma (blood cancer), or non-malignant hematological disorders, who were admitted for a fertility preservation programme between 2002 and 2018.PARTICIPANTS/MATERIALS, SETTING, METHODSIn addition to clinical data, we analyzed measurements of testicular volume and performed histological staining on testicular biopsies obtained before treatment, at cryopreservation, to evaluate number of spermatogonia per tubular cross-section, tubular fertility index, and the most advanced germ cell type prior to chemo-/radiotherapy. The controls were data simulations with summary statistics from original studies reporting healthy prepubertal boys’ testes characteristics.MAIN RESULTS AND THE ROLE OF CHANCEPrepubertal patients with childhood cancer or hematological disorders were more likely to have significantly reduced spermatogonial quantity compared to healthy controls (48.5% versus 31.0% prevalence, respectively). The prevalence of patients with reduced spermatogonial quantity was highest in the CNS tumor (56.7%) and the hematological disorder (55.6%) groups, including patients with hydroxyurea pre-treated sickle cell disease (58.3%) and patients not exposed to hydroxyurea (50%). Disease also adversely impacted spermatogonial distribution and differentiation. Irrespective of disease, we observed the highest spermatogonial quantity reduction in patients <7 years of age.LIMITATIONS, REASONS FOR CAUTIONFor ethical reasons, we could not collect spermatogonial quantity data in healthy prepubertal boys as controls and thus deployed statistical simulation on data from literature. Also, our results should be interpreted considering low patient numbers per (sub)group.WIDER IMPLICATIONS OF THE FINDINGSCancers, especially CNS tumors, and severe hematological disorders can affect spermatogonial quantity in prepubertal boys before treatment. Consequently, these patients may have a higher risk of depleted spermatogonia following therapies, resulting in persistent infertility. Therefore, patient counseling prior to disease treatment and timing of fertility preservation should not only be based on treatment regimes, but also on diagnoses and age.STUDY FUNDING/COMPETING INTEREST(S)This study was supported by Marie Curie Initial Training Network (ITN) (EU-FP7-PEOPLE-2013-ITN) funded by European Commision grant no. 603568; ZonMW Translational Adult stem cell research (TAS) grant no. 116003002. No competing interests.TRIAL REGISTRATION NUMBERN/A.
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| 3. |
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| 4. |
- Hudak, O. E., et al.
(författare)
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Improved corrosion resistance of cathodic arc evaporated Al0.7Cr0.3_xVxN coatings in NaCl-rich media
- 2023
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 221
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Tidskriftsartikel (refereegranskat)abstract
- The corrosion resistance of cathodic arc evaporated Al0.7Cr0.3_xVxN coatings with a vanadium content up to 22.3 at% has been electrochemically tested in a 0.1 M NaCl-solution. Significant improvement in the open porosity and corrosion rate was observed for coatings with higher V-contents, due to a denser and more refined coating morphology. Further reduction in the open porosity rate was achieved through an annealing step in air at 700 degrees C. Here, the formation of an AlVO4 top-oxide and underlying oxygen-rich V-depletion zone provides additional sealing of the coating surface, whilst reducing the corrosion current density to a final 1.59 x 10_9 A/cm2.
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| 5. |
- Kokkoris, M., et al.
(författare)
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Benchmarking the evaluated proton differential cross sections suitable for the EBS analysis of natSi and 16O
- 2017
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 405, s. 50-60
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Tidskriftsartikel (refereegranskat)abstract
- The evaluated proton differential cross sections suitable for the Elastic Backscattering Spectroscopy (EBS) analysis of Si-nat and O-16, as obtained from SigmaCalc 2.0, have been benchmarked over a wide energy and angular range at two different accelerator laboratories, namely at N.C.S.R. 'Demokritos', Athens, Greece and at Ruder Boskovic Institute (RBI), Zagreb, Croatia, using a variety of high-purity thick targets of known stoichiometry. The results are presented in graphical and tabular forms, while the observed discrepancies, as well as, the limits in accuracy of the benchmarking procedure, along with target related effects, are thoroughly discussed and analysed. In the case of oxygen the agreement between simulated and experimental spectra was generally good, while for silicon serious discrepancies were observed above E-p,E-lab = 2.5 MeV, suggesting that a further tuning of the appropriate nuclear model parameters in the evaluated differential cross-section datasets is required.
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| 6. |
- Maragkos, F., et al.
(författare)
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Differential cross-section measurements and R-Matrix calculations for proton elastic scattering on natMg in the energy range Ep,lab=2.70-4.25 MeV, suitable for EBS
- 2023
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier. - 0168-583X .- 1872-9584. ; 536, s. 45-54
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Tidskriftsartikel (refereegranskat)abstract
- In the current work the first coherent set of differential cross section values for the natMg(p,p0)natMg elastic scattering covering the Ep,lab = 2700-4250 keV energy range is presented for 6 backscattering detection angles (120 degrees, 130 degrees, 140 degrees, 150 degrees, 160 degrees and 170 degrees). R-Matrix calculations were implemented using the AZURE 2.0 code [1] in an attempt to reproduce the obtained experimental data, whilst taking into account the 24Mg(p,p1)24Mg reaction channel. Both results are suitable for EBS and other IBA applications and, furthermore, they form a basis for a future expansion of the current SigmaCalc [2] evaluation, once more experimental data become available. The measurements were performed in the 5.5 MV TN11 HV Tandem Accelerator and the high precision goniometer of N.C.S.R. 'Demokritos', Athens, Greece. The experimental and data analysis procedures are presented in detail, along with the process behind the implementation of the R-Matrix calculations.
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