A comparative study of electronic cigarette vapour extracts on airway-related cell lines in vitro

The use of electronic cigarettes (ECs) is rapidly increasing worldwide; however, scientific evidence regarding EC cytotoxicity is limited. The aim of this study was to evaluate the acute cytotoxicity of EC vapor extract (ECE) on airway-related cells in vitro. Cigarette smoke extract (CSE), vapor extract of fifteen brands/flavors of ECs and the extract from the E-vehicle (propylene glycol and glycerin) was collected. Extracts, in concentrations of 100–12.5%, were added to human bronchial epithelial (BEAS-2B, IB3-1 and C38), fibroblast (Wi-38) and macrophage (J774 and THP-1) cell lines. Viability was assessed after 24 h using a standard XTT assay. Viability of <70% of control (no extract) was considered cytotoxic according to UNI EN ISO 10993-5 standards. CSE displayed a concentration-dependent influence on cell viability across all four cell lines with 100% producing the most toxic effect, therefore validating the model and indicating higher cytotoxicity than in ECEs. ECEs did reduce viability although this was not correlated with nicotine content or the E-vehicle. However, several flavors proved cytotoxic, with variation between different brands and cell lines. These data indicate that not all ECs are the same and that use of a particular flavor or brand may have differing effects. The cell line used is also an important factor. More research is crucial to ascertain the health effects of different ECs before they can be accepted as a safe alternative to tobacco cigarettes

Using Light Charged Particles to Probe the Asymmetry Dependence of the Nuclear Caloric Curve

Recently, we observed a clear dependence of the nuclear caloric curve on neutron-proton asymmetry $\frac{N-Z}{A}$ through examination of fully reconstructed equilibrated quasi-projectile sources produced in heavy ion collisions at E/A = 35 MeV. In the present work, we extend our analysis using multiple light charged particle probes of the temperature. Temperatures are extracted with five distinct probes using a kinetic thermometer approach. Additionally, temperatures are extracted using two probes within a chemical thermometer approach (Albergo method). All seven measurements show a significant linear dependence of the source temperature on the source asymmetry. For the kinetic thermometer, the strength of the asymmetry dependence varies with the probe particle species in a way which is consistent with an average emission-time ordering.Comment: 7 pages, 4 figure

Analyzing power and cross section distributions of the 12C (p,pα)8Be cluster knockout reaction at an incident energy of 100 MeV

Thesis (PhD (Physics))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: The (p, pα) reaction on 12C was investigated experimentally using polarized incident protons of 100 MeV. Coincident data, which were obtained at ten quasifree angle pairs for proton angles ranging from 25◦ to 110◦, were analyzed in terms of the distorted-wave impulse approximation (DWIA). Calculated energy-sharing cross section and analyzing power distributions reproduce the data reasonably well. The observed agreement allows the extraction of distorted momentum distributions from experimental data. These distributions are very consistent over a wide range of angle pairs at which cross section energy-sharing distributions vary considerably. Since measurements of analyzing powers were made, spin-orbit distortions were included in the DWIA calculations. The effects of spin-orbit distortions were found to be very small near zero recoil momentum and did not destroy the validity of the factorization approximation where the two-body p-α cross section enters as a multiplicative factor in the three-body (p, pα) cross section expression. Spectroscopic factors derived from the data are fairly consistent with the trend of the theoretical predictions. Analyzing power data also follow the trend of free p-4He scattering data, and comparisons with DWIA predictions are in reasonable agreement. The theory reproduces also very well analyzing power angular distributions of the projectile-cluster two-body scattering at large angular momentum of the residual nucleus. This indicates that a quasifree knockout mechanism dominates the reaction. The two-body interaction response between the projectile and the α cluster was found to resemble the scattering of protons from a free α particle to a remarkable degree, the present results strongly imply the existence of preformed α clusters in 12C.AFRIKAANSE OPSOMMING: Die (p, pα) reaksie op 12C is eksperimenteel ondersoek deur middel van gepolariseerde protone met n invalsenergie van 100 MeV. Ko¨ınsidensie data, wat verkry is by tien kwasievrye hoekpare, met proton hoeke tussen 25◦ en 110◦, is geanaliseer in terme van die vervormde-golf-impuls-benadering (DWIA). Die berekende energie-verdeelde kansvlak en analiseervermo¨e verspreidings reproduseer die data redelik goed. Die waargenome ooreenstemming maak dit moontlik om vervormde momentumverdelings uit die eksperimentele data te verkry. Aangesien analiseervermo¨e metings gedoen is, is spin-baan wisselwerking by die DWIA berekenige ingesluit. Die bydra as gevolg van spin-baan wisselwerking blyk baie klein te wees naby nul terugslag momentum en het nie die geldigheid van die faktoriseringsbenadering, waartydens die twee-deeltjie, p-α kansvlak as ’n vermenigvuldigingsfaktor in die uitdrukking vir die drie-deeltjie (p, pα) kansvlak verskyn, vernietig nie. Spektroskopiese faktore wat uit die data herlei is, is redelik konsistent met die verloop van die teoretiese voorspellings. Analiseervermo¨e data volg ook die verloop van die vrye p-4He verstrooiings-data en vergelyk redelik goed met DWIA voorspellings. Die teorie reproduseer ook die hoekverdelings in die analiseervermo¨e van die twee-deeltjie projektiel-bondel verstrooiing by groot hoekmomentum waardes vir die oorblywende kern baie goed. Dit dui daarop dat ’n kwasie-vrye uitslaanmeganisme die reaksie domineer. Die twee-deeltjie wisselwerkingsgedrag tussen die projektiel en die α-bondel toon sterk ooreenkomste met die verstrooiing van protone vanaf ’n vrye α-deeltjie. Die huidige resultate lewer sterk bewyse vir die bestaan van voorafgevormde α-bondels in 12C

Enhanced production of

The reaction of a 100Mo beam at 12 MeV/nucleon impinging on a 4He gas-cell target was performed. The 99Mo alongside other coproduced isotopes were collected after the gas target on an aluminum catcher foil and their respective radioactivities were measured by offline γ-ray analysis. In this contribution, preliminary experimental results which are used to discuss the possibility of optimal large-scale production conditions of the produced radioisotopes are presented

A novel approach to medical radioisotope production using inverse kinematics

The inverse kinematics methodology using a gas target has been applied to produce medically important radionuclides at the Cyclotron Institute at Texas A&M University. The production of the theranostic radionuclide 67Cu (T1/2 = 62 h) through the reaction of a 70Zn beam at 15 MeV/nucleon with a hydrogen gas target was performed. The activities at end of irradiation and the thick target yield were obtained for 67Cu. A test using the forward-focused neutrons from the primary reaction to irradiate natZn to produce 67Cu is also presented

Clustering in light nuclei and their effects on fusion and pre – equilibrium processes.

The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is important to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions [1–5]. The NUCL–EX collaboration has recently initiated an experimental campaign of exclusive measurements of fusion–evaporation reactions with light nuclei as interacting partners. In collisions involving light systems, the low expected multiplicity of fragments increases the probability of achieving a quasi-complete reconstruction of the event. In particular the formation and decay modes of an excited 24Mg system have been studied through two different reactions, 12C (95 MeV)+ 12C and 14N (80.7 MeV)+ 10B, which have been used to produce fused systems with nearly the same mass and excitation energy (~60 MeV). In particular, even the de-excitation of the Hoyle state in 12C have been studied, both in peripheral (projectiles de-excitation) and in central collisions (six α-particles channel). Moreover, a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei has been carried out. For this purpose, a comparative study of the three nuclear systems 18O+28Si, 16O+30Si and 19F+27Al has been recently studied using the GARFIELD+RCo 4π setup [6]. The experimental data are compared with the predictions of simulated events generated with the statistical models (GEMINI++ and HFl) and through dynamical models like Stochastic Mean Field (SMF) and Antisymmetrized Molecular Dynamics (AMD) and filtered with a software replica of our apparatus in order to take into account the experimental conditions

Clustering in light nuclei and their effects on fusion and pre – equilibrium processes.

International audienceThe study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is important to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions [1–5]. The NUCL–EX collaboration has recently initiated an experimental campaign of exclusive measurements of fusion–evaporation reactions with light nuclei as interacting partners. In collisions involving light systems, the low expected multiplicity of fragments increases the probability of achieving a quasi-complete reconstruction of the event. In particular the formation and decay modes of an excited 24Mg system have been studied through two different reactions, 12C (95 MeV)+ 12C and 14N (80.7 MeV)+ 10B, which have been used to produce fused systems with nearly the same mass and excitation energy (~60 MeV). In particular, even the de-excitation of the Hoyle state in 12C have been studied, both in peripheral (projectiles de-excitation) and in central collisions (six α-particles channel). Moreover, a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei has been carried out. For this purpose, a comparative study of the three nuclear systems 18O+28Si, 16O+30Si and 19F+27Al has been recently studied using the GARFIELD+RCo 4π setup [6]. The experimental data are compared with the predictions of simulated events generated with the statistical models (GEMINI++ and HFl) and through dynamical models like Stochastic Mean Field (SMF) and Antisymmetrized Molecular Dynamics (AMD) and filtered with a software replica of our apparatus in order to take into account the experimental conditions