Dependence of Megaelectron Volt Time-of-Flight Secondary Ion Mass Spectrometry Secondary Molecular Ion Yield from Phthalocyanine Blue on Primary Ion Stopping Power

Time-of-flight secondary ion mass spectrometry (TOF SIMS) is a well-established mass spectrometry technique used for the chemical analysis of both organic and inorganic materials. In the last ten years, many advances have been made to improve the yield of secondary molecular ions, especially those desorbed from the surfaces of organic samples. For this reason, cluster ion beams with kiloelectron volt energies for the excitation were mostly used. Alternatively, single-ion beams with megaelectron volt energies can be applied, as was done in the present work. It is well-known that a secondary molecule/ion yield depends strongly on the primary ion stopping power, but the nature of this dependence is not completely clear. Therefore, in the present work, the secondary ion yield from the phthalocyanine blue (C32H16CuN8, organic pigment) was measured for the various combinations of ion masses, energies, and charge states. Measured values were compared with the existing models for ion sputtering. An increase in the secondary yield with the primary ion energy, electronic stopping, velocity, and charge state was found for different types of primary ions. Although this general behavior is valid for all primary ions, there is no single parameter that can describe the measured results for all primary ions at once

Influence of a vertical subject on research in biomedicine and activities of The Cochrane Collaboration branch on medical students’ knowledge and attitudes toward evidencebased medicine

Aim To investigate whether the introduction of a vertical subject on research in biomedicine and founding of The Cochrane Collaboration branch at the University of Split School of Medicine influenced students’ knowledge and attitudes toward evidence-based medicine (EBM), including the use of research literature. Methods We used a 26-item questionnaire on EBM knowledge and attitudes to survey 1232 medical students of all study years in 3 medical schools in Croatia (Split, Rijeka, Osijek) and the Croatian-speaking medical school in Mostar (Bosnia and Herzegovina). Results Students from the University of Split School of Medicine who had been exposed to the vertical subject on research in biomedicine and activities of The Cochrane Collaboration at the school had better knowledge and more positive attitudes toward EBM. In general, students rarely searched for evidence; 28% of students searched for evidence more than once a month and 96% of students used only textbooks in Croatian and teachers’ handouts, even though 74% of students agreed that articles from scholarly journals were an important supplement for textbooks. Conclusion Building up an environment that fosters EBM may be beneficial for students’ knowledge and attitudes toward EBM. Teachers should encourage and require using evidence during all the courses in medical schoo

Depth profiling of Cr-ITO dual-layer sample with secondary ion mass spectrometry using MeV ions in the low energy region

This work explores the possibility of depth profiling of inorganic materials with Megaelectron Volt Secondary Ion Mass Spectrometry using low energy primary ions (LE MeV SIMS), specifically 555 keV Cu ²⁺ , while etching the surface with 1 keV Ar ⁺ ions. This is demonstrated on a dual-layer sample consisting of 50 nm Cr layer deposited on 150 nm In2O5Sn (ITO) glass. These materials proved to have sufficient secondary ion yield in previous studies using copper ions with energies of several hundred keV. LE MeV SIMS and keV SIMS depth profiles of Cr-ITO dual-layer are compared and corroborated by atomic force microscopy (AFM) and time-of-flight elastic recoil detection analysis (TOF-ERDA). The results show the potential of LE MeV SIMS depth profiling of inorganic multilayer systems in accelerator facilities equipped with MeV SIMS setup and a fairly simple sputtering source

Analysis of cyclic fatigue resistance of ProTaper Universal and ProTaper Next rotary instruments

Introduction Root canal preparation is one of the most important active phases in the treatment of infected and noninfected teeth. Nickel-titanium (NiTi) instruments are increasingly used in endodontic therapy due to their superior properties compared to those made of stainless steel. The aim of this research was to perform an analysis and comparison of cyclic fatigue in ProTaper Universal and ProTaper Next rotary NiTi instruments in full rotation in simulated canals. Material and methods Twelve ProTaper Next and twelve ProTaper Universal instruments were analyzed in the study. The instruments were tested in an artificial canal stuffed in a metal block at an angle of 45° and a corner radius of 5 mm. The operating time of each instrument until fracture was measured and the number of cycles to fracture (NCF) calculated. Results ProTaper Next instruments showed greater resistance to cyclic fatigue compared to ProTaper Universal. The NCF value was significantly higher in ProTaper Next (1,296.83±20.2) instruments (p<0.001). The average length of fractured fragments was statistically significantly higher in ProTaper Universal (4.52±0.33) instruments compared to ProTaper Next (3.82±0.27) (p<0.001). Conclusion It was concluded that the cyclic fatigue resistance of ProTaper Next instruments was higher compared to ProTaper Universal instruments

Cyclic fatigue testing of ProTaper Universal and ProTaper Next rotary instruments of different diameters

Introduction Sudden fracture of instruments without previous warning signs, which occurs due to cyclic and torsional fatigue, represents the biggest problem and one of the most difficult complications during endodontic therapy. The aim of this research was to check the influence of diameter of the instruments on the appearance of cyclic fatigue in simulated canals in full rotation. Material and Method The study analyzed 24 ProTaper Universal instruments (12 instruments with a diameter of 25 and 12 instruments with a diameter of 30) and 24 ProTaper Next instruments (12 instruments with a diameter of 25 and 12 instruments with a diameter of 30). The instruments were tested in an artificial canal stuffed in a metal block at an angle of 45° and a corner radius of 5 mm. The operating time of each instrument until fracture was measured, and then the number of cycles to fracture (NCF) was calculated. The length of the fractured fragments (FL) was measured with a Vernier caliper. Results The number of cycles to fracture was higher (p < 0.001) in instruments of the ProTaper Universal group of diameter 25 (367.83 ± 17.00) compared to instruments of diameter 30 (329.33 ± 12.86) of the same group. The number of cycles leading to the fracture in instruments of the ProTaper Next group of diameter 25 (1189.33 ± 18.97) was higher (p < 0.001) compared to instruments of the same group of diameter 30 (971.08 ± 15.26). Conclusion Obtained results indicated that with an increase in the diameter of rotating endodontic instruments, there is a decrease in the resistance to cyclic fatigue

The influence of secondary effects in XRF analysis

U ovom radu dan je teorijski uvod u fiziˇcke efekte u spektroskopiji karakteristiˇcnim X-zrakama (XRF), eksperimentalni postav i teoriju fundamentalnih parametara te je opisan naˇcin rada programskog koda (danog u prilogu) koji se tiˇce kalibracije na primjeru XRF sustava u Laboratoriju za elementnu mikroanalizu Odjela za fiziku Sveuˇcilišta u Rijeci. Kronološki je objašnjen proces kalibracije tankih standarda, a potom su rezultati iskorišteni u analizi metalnih legura (debelih standarda) kako bi se ispitao uˇcinak sekundarne fluorescencije u uzorcima. Efekti sekundarne fluorescencije u kvantitativnoj XRF analizi zanemarivi su u tankim metama, no u sluˇcaju debelih meta nužne su korekcije intenziteta karakteristiˇcnih X-zraka. Programski paket VIBA-Lab pisan u Javi nudi mogu´cnost kalibracije sustava na standardima i kvantitativne XRF analize nepoznatih uzoraka na temelju teorije fundamentalnih parametara. Pri kraju rada su, pomo´cu Java programskog koda implementiranog u VIBA-Lab, izrad¯ene simulacije kalibracijskih krivulja za željezo u raznim binarnim matricama kako bi se bolje pojasnilo na koji naˇcin djeluju sekundarni efekti, ali i efekti apsorpcije u matrici

Imaging of Organic Samples with Megaelectron Volt Time-of-Flight Secondary Ion Mass Spectrometry Capillary Microprobe

Time-of-flight Secondary Ion Mass Spectrometry (TOF SIMS) with MeV primary ions offers a fine balance between secondary ion yield for molecules in the mass range from 100 to 1000 Da and beam spot size, both of which are critical for imaging applications of organic samples. Using conically shaped glass capillaries with an exit diameter of a few micrometers, a high energy heavy primary beam can be collimated to less than 10 μm. In this work, imaging capabilities of such a setup are presented for some organic samples (leucine-evaporated mesh, fly wing section, ink deposited on paper). Lateral resolution measurement and molecular distributions of selected mass peaks are shown. The negative influence of the beam halo, an unavoidable characteristic of primary beam collimation with a conical capillary, is also discussed. A new start trigger for TOF measurements based on the detection of secondary electrons released by the primary ion is presented. This method is applicable for a continuous primary ion beam, and for thick targets that are not transparent to the primary ion beam. The solution preserves the good mass resolution of the thin target setup, where the detection of primary ions with a PIN diode is used for a start trigger, reduces the background, and enables a wide range of samples to be analyzed