The role of collisional ionization in heavy ion acceleration by high intensity laser pulses

We present here simulation results of the laser-driven acceleration of gold ions using the EPOCH code. Recently, an experiment reported the acceleration of gold ions up to 7 MeV/nucleon with a strong dependency of the charge-state distribution on target thickness and the detection of the highest charge states Z∼72. Our simulations using a developmental branch of EPOCH (4.18-Ionization) show that collisional ionization is the most important cause of charge states beyond Z = 51 up to He-like Au

Evaluation of the incidence and pattern of early childhood dental caries and effective factors on 2-6 year old children in Hamedan in 2006

Background: Prolonged bottle and breast feeding may result in Early Childhood Caries (ECC). The clinical appearance of teeth in ECC in the children is typical and follow a definitive pattern. The goal of this study was to investigate the prevalence of ECC and its dependent factors in Hamadan Kindergarten's children in 2006. Materials and Methods: In this cross-sectional descriptive study, ECC data were collected using questionnaires from 414 children with age range of 2-6 years by a dentist. The relationship between early childhood caries and bottle or breast feeding, period of feeding, use of sweetening materials, frequency of feeding at night, and first time brushing were recorded. Data were analyzed with T-test and Chi- square test. Results : The prevalence of ECC was 31.7. The most affected teeth were left maxillary incisors (28.01) and least affected left lower canine (0). There was a meaningful correlation between breast feeding and ECC. There was no correlation between ECC and age, sex, first time brushing, feeding period, use of sweetening materials, bottle feeding and feeding at night. Conclusion: The prevalence of ECC was high in the studied population and there was a relationship between breast feeding and it's duration with ECC

Theory of circularly polarized harmonic generation using bi-colour lasers in underdense plasmas

Circularly polarized (CP) extreme ultraviolet- and x-ray radiation is an essential tool for analyzing the magnetic properties of materials. Elliptically polarized high harmonic generation (HHG) has been demonstrated by focusing bi-chromatic (800 + 400 nm wavelengths), counter-rotating CP laser pulses into gas targets (Fleischer et al 2014 Nat. Photonics 8 543). More recent theoretical studies indicate that a bi-circular laser driver can also work in both under- and overdense plasmas with analogous selection rules to those in gases: for example, every third harmonic is suppressed and adjacent harmonics have opposite helicity for counter-polarized CP ω0 and 2ω0 pumps. In this work, an analytical theory of bi-circular HHG from underdense plasmas is formulated which provides quantitative predictions of harmonic efficiency scaling, selectivity and helicity for both co- and counter-polarized drivers of arbitrary frequency ratio. This is compared to a fully non-linear, one-dimensional fluid model and particle-in-cell simulations, showing good agreement with both

In vitro gastrointestinal evaluation of a juçara-based smoothie: effect of processing on phenolic compounds bioaccessibility

In the present work, the bioaccessibility of the main phenolic compounds of a juçara, banana and strawberry homogenized smoothie (control), subjected to pasteurization and sonication, was evaluated. The smoothie was also evaluated in terms of its main chemical and physical characteristics. Pasteurized smoothie showed higher apparent viscosity, as well as higher initial shear stress when compared to the control and sonicated samples. The increase in the apparent viscosity of the pasteurized smoothie was associated with the smaller particle size of this sample (68 µm). These characteristics conferred to the pasteurized smoothie higher physical stability than the control and sonicated smoothies. Phenolic compounds bioaccessibility was higher in the pasteurized and sonicated smoothies than in the control sample, which confirmed the positive effect of the treatments for the preservation of these compounds after gastrointestinal digestion. Compared to the sonication process, the pasteurization provided higher total phenolic compounds bioaccessibility (47%), as well as of ferulic (16%) and ellagic (80%) acids. Antioxidant capacity was higher in gastric digest for all the samples evaluated by ABTS assay. These results confirm the importance of processing on the physical stability and phenolic compounds bioaccessibility of the juçara-based smoothie, standing out the thermally treated product.The authors are incredibly grateful to Federal University of Rio de Janeiro, Embrapa Agro indústria de Alimentos and University of Minho for support. Leilson O. Ribeiro acknowledge the Capes for his fellowship (88881.133775/2016-01) and Ana C. Pinheiro acknowledge the Foundation for Science and Technology (FCT) for her fellowship (SFRH/BPD/101181/2014).info:eu-repo/semantics/publishedVersio