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Particle physics

Antonella Fogliata, Francesca Lobefalo, Giacomo Reggiori, Antonella Stravato, Stefano Tomatis, Marta Scorsetti, Luca Cozzi
PURPOSE: Small field measurements are challenging, due to the physical characteristics coming from the lack of charged particle equilibrium, the partial occlusion of the finite radiation source, and to the detector response. These characteristics can be modeled in the dose calculations in the treatment planning systems. Aim of the present work is to evaluate the MU calculation accuracy for small fields, defined by jaw or MLC, for anisotropic analytical algorithm (AAA) and Acuros XB algorithms, relative to output measurements on the beam central axis...
October 2016: Medical Physics
Jeppe Brage Christensen, Heikki Tölli, Niels Bassler
PURPOSE: Dosimetry with ionization chambers in clinical ion beams for radiation therapy requires correction for recombination effects. However, common radiation protocols discriminate between initial and general recombination and provide no universal correction method for the presence of both recombination types in ion beams of charged particles heavier than protons. The advent of multiple field optimization in ion beams, allowing for complex patterns of dose delivery in both temporal and spatial domains, results in new challenges for recombination correction where the resulting recombination depends on the plan delivered...
October 2016: Medical Physics
Roland Kjellander
Screened electrostatic interactions in ionic liquids are investigated by means of exact statistical mechanical analysis combined with physical arguments that enhance the transparency and conceptual accessibility of the analysis and results. The constituent ions and immersed particles in the liquid can have arbitrary shapes and any internal charge distributions. The decay of the screened electrostatic potential and the free energy of interaction in ionic liquids can be exponentially damped oscillatory (like in molten simple salts) as well as plain exponential and long-ranged (like in dilute electrolyte solutions)...
September 28, 2016: Journal of Chemical Physics
Saleem Aslam, Najam Ul Hasan, Adnan Shahid, Ju Wook Jang, Kyung-Geun Lee
The Internet of Things (IoT) has gained an incredible importance in the communication and networking industry due to its innovative solutions and advantages in diverse domains. The IoT' network is a network of smart physical objects: devices, vehicles, buildings, etc. The IoT has a number of applications ranging from smart home, smart surveillance to smart healthcare systems. Since IoT consists of various heterogeneous devices that exhibit different traffic patterns and expect different quality of service (QoS) in terms of data rate, bit error rate and the stability index of the channel, therefore, in this paper, we formulated an optimization problem to assign channels to heterogeneous IoT devices within a smart building for the provisioning of their desired QoS...
October 6, 2016: Sensors
Jakarwan Yostawonkul, Suvimol Surassmo, Tawin Iempridee, Wittaya Pimtong, Kunat Suktham, Warayuth Sajomsang, Pattarapond Gonil, Uracha Rungsardthong Ruktanonchai
A nanostructure lipid carrier (NLC) composed of solid, and liquid lipid as a core has been developed as a delivery system for hydrophobic drug molecules. The aim of this research was to fabricate an oleoyl-quaternized-chitosan (CS)-coated NLC, where the mucoadhesive property of nanoparticles is enhanced for more efficient drug delivery. NLC loaded with alpha-mangostin (AP), a model hydrophobic drug, were fabricated using a high pressure homogenization process and subsequently coated with CS. The fabricated nanoparticles showed particle sizes in the range of 200-400nm, with low polydispersity, high physical stability and excellent encapsulation efficiency (EE>90%)...
September 29, 2016: Colloids and Surfaces. B, Biointerfaces
Olga A Yakovina, Alexander S Lisitsyn
Metal clusters with sizes below 1 nm excite great scientific interest, but the main information on their properties still comes from quantum mechanics modeling and costly physical methods of limited availability. We have studied ultradispersed Pt/γ-Al2O3 samples with TPD and complementary adsorption/desorption techniques and observed a strong influence of H2-treatment conditions (PH2 ≤ 1 bar; 200 K ≤ T ≤ 470 K) on the H2-TPD profile of Pt/γ-Al2O3. The results corroborate recent theoretical and spectroscopic studies predicting alterations in the structure of Pt nanoclusters under H2 but reveal that the restructuring needs to overcome continuous activation barriers and leads both to an increase in surface coverage and strengthening of Pt-H bonds...
October 25, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Chrystelle Neaime, Maria Amela-Cortes, Fabien Grasset, Yann Molard, Stéphane Cordier, Benjamin Dierre, Michel Mortier, Toshiaki Takei, Kohsei Takahashi, Hajime Haneda, Marc Verelst, Séverine Lechevallier
Bioimaging and cell labeling using red or near infrared phosphors emitting in the "therapeutic window" of biological tissues have recently become some of the most active research fields in modern medical diagnostics. However, because organic and inorganic autofluorophores are omnipresent in nature, very often the background signal from fluorochromes other than targeted probes has to be eliminated. This discrimination could be available using a time-gated luminescence microscopy (TGLM) technique associated with long lifetime phosphorescent nanocomposites...
October 25, 2016: Physical Chemistry Chemical Physics: PCCP
(no author information available yet)
No abstract text is available yet for this article.
October 25, 2016: Nature Materials
Sergey Alekhin, Wolfgang Altmannshofer, Takehiko Asaka, Brian Batell, Fedor Bezrukov, Kyrylo Bondarenko, Alexey Boyarsky, Ki-Young Choi, Cristóbal Corral, Nathaniel Craig, David Curtin, Sacha Davidson, André de Gouvêa, Stefano Dell'Oro, Patrick deNiverville, P S Bhupal Dev, Herbi Dreiner, Marco Drewes, Shintaro Eijima, Rouven Essig, Anthony Fradette, Björn Garbrecht, Belen Gavela, Gian F Giudice, Mark D Goodsell, Dmitry Gorbunov, Stefania Gori, Christophe Grojean, Alberto Guffanti, Thomas Hambye, Steen H Hansen, Juan Carlos Helo, Pilar Hernandez, Alejandro Ibarra, Artem Ivashko, Eder Izaguirre, Joerg Jaeckel, Yu Seon Jeong, Felix Kahlhoefer, Yonatan Kahn, Andrey Katz, Choong Sun Kim, Sergey Kovalenko, Gordan Krnjaic, Valery E Lyubovitskij, Simone Marcocci, Matthew Mccullough, David McKeen, Guenakh Mitselmakher, Sven-Olaf Moch, Rabindra N Mohapatra, David E Morrissey, Maksym Ovchynnikov, Emmanuel Paschos, Apostolos Pilaftsis, Maxim Pospelov, Mary Hall Reno, Andreas Ringwald, Adam Ritz, Leszek Roszkowski, Valery Rubakov, Oleg Ruchayskiy, Ingo Schienbein, Daniel Schmeier, Kai Schmidt-Hoberg, Pedro Schwaller, Goran Senjanovic, Osamu Seto, Mikhail Shaposhnikov, Lesya Shchutska, Jessie Shelton, Robert Shrock, Brian Shuve, Michael Spannowsky, Andy Spray, Florian Staub, Daniel Stolarski, Matt Strassler, Vladimir Tello, Francesco Tramontano, Anurag Tripathi, Sean Tulin, Francesco Vissani, Martin W Winkler, Kathryn M Zurek
This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, [Formula: see text] and to search for weakly-interacting sub-GeV dark matter candidates...
December 2016: Reports on Progress in Physics
Wan-Yi Li, Xia Li, Steffen Jockusch, Han Wang, Bolei Xu, Yajing Wu, William Gang Tsui, Hai-Lung Dai, V Faye McNeill, Yi Rao
Photoactivated reactions of organic species in atmospheric aerosol particles are a potentially significant source of secondary organic aerosol material (SOA). Despite recent progress, the dominant chemical mechanisms and rates of these reactions remain largely unknown. In this work, we characterize the photo-physical properties and photochemical reaction mechanisms of imidazole-2-carboxaldehyde (IC) in aqueous solution, alone and in the presence of isoprene. IC has been shown previously in laboratory studies to participate in photoactivated chemistry in aerosols, and is a known in-particle reaction product of glyoxal...
October 24, 2016: Journal of Physical Chemistry. A
Nghi C Nguyen, Muhammad Shah, Leonard J Appleman, Rahul Parikh, James M Mountz
Background and Purpose. Radium-223 dichloride (Xofigo®, Bayer HealthCare Pharmaceuticals Inc.) is the first α-particle emitter therapeutic agent approved by the FDA, with benefits in overall survival and delay in symptomatic skeletal event for patients with metastatic castrate-resistant prostate cancer (CRPC). Recent post hoc analyses of the phase III ALSYMPCA trial support the previously established safety profile as well as therapeutic effect and clinical outcome of Radium-223. Currently, Radium-223 is approved as a single agent therapy for metastatic CRPC...
2016: International Journal of Molecular Imaging
Sarthok Sircar, Giang Nguyen, Andrei Kotousov, Anthony J Roberts
A self-consistent model is developed to investigate attachment/detachment kinetics of two static, deformable microspheres with irregular surface and coated with flexible binding ligands. The model highlights how the microscale binding kinetics of these ligands as well as the attractive/repulsive potential of the charged surface affects the macroscale static deformed configuration of the spheres. It is shown that in the limit of smooth, neutrally charged surface (i.e., the dimensionless inverse Debye length, [Formula: see text]), interacting via elastic binders (i...
October 2016: European Physical Journal. E, Soft Matter
Juris Ulmanis, Stephan Häfner, Rico Pires, Eva D Kuhnle, Yujun Wang, Chris H Greene, Matthias Weidemüller
We investigate theoretically and experimentally the heteronuclear Efimov scenario for a three-body system that consists of two bosons and one distinguishable particle with positive intraspecies scattering lengths. The three-body parameter at the three-body scattering threshold and the scaling factor between consecutive Efimov resonances are found to be controlled by the scattering length between the two bosons, approximately independent of short-range physics. We observe two excited-state Efimov resonances in the three-body recombination spectra of an ultracold mixture of fermionic ^{6}Li and bosonic ^{133}Cs atoms close to a Li-Cs Feshbach resonance, where the Cs-Cs interaction is positive...
October 7, 2016: Physical Review Letters
Francesca Bomboi, Flavio Romano, Manuela Leo, Javier Fernandez-Castanon, Roberto Cerbino, Tommaso Bellini, Federico Bordi, Patrizia Filetici, Francesco Sciortino
DNA is acquiring a primary role in material development, self-assembling by design into complex supramolecular aggregates, the building block of a new-materials world. Using DNA nanoconstructs to translate sophisticated theoretical intuitions into experimental realizations by closely matching idealized models of colloidal particles is a much less explored avenue. Here we experimentally show that an appropriate selection of competing interactions enciphered in multiple DNA sequences results into the successful design of a one-pot DNA hydrogel that melts both on heating and on cooling...
October 21, 2016: Nature Communications
Daniel R Reid, Ivan Lyubimov, M D Ediger, Juan J de Pablo
Glass films prepared by a process of physical vapour deposition have been shown to have thermodynamic and kinetic stability comparable to those of ordinary glasses aged for thousands of years. A central question in the study of vapour-deposited glasses, particularly in light of new knowledge regarding anisotropy in these materials, is whether the ultra-stable glassy films formed by vapour deposition are ever equivalent to those obtained by liquid cooling. Here we present a computational study of vapour deposition for a two-dimensional glass forming liquid using a methodology, which closely mimics experiment...
October 20, 2016: Nature Communications
Koen E Merkus, Menno W J Prins, Cornelis Storm
Tethered particle motion (TPM), the motion of a micro- or nanoparticle tethered to a substrate by a macromolecule, is a system that has proven to be extremely useful for its ability to reveal physical features of the tether, because the thermal motion of the bound particle reports sensitively on parameters like the length, the rigidity, or the folding state of its tether. In this article, we survey the applicability of TPM to probe the kinetics of single secondary bonds, bonds that form and break between the tethered particle and a substrate due, for instance, to receptor/ligand pairs on particle and substrate...
October 18, 2016: Biophysical Journal
Xiao Chun Cong, Jing Hua Qu, Guo Shu Yang
To obtain physical properties of pollutant concentrations encountered by vehicle commuters during travelling Yangkou tunnel (7.76 km) of Qingdao City, particle concentration measurements are accompanied by the measurements of gaseous species (CO and CO2). The field campaigns are on-road conducted from April 26 to September 23, 2014. Results demonstrate that the mean particle number concentrations observed within the tunnel at the normal traffic volume are 1.15 × 10(5) and 1.24 × 10(5) particles cm(-3) for the southbound and northbound trip, respectively...
October 18, 2016: Environmental Geochemistry and Health
Habteab Habtom, Sandrine Demanèche, Lorna Dawson, Chen Azulay, Ofra Matan, Patrick Robe, Ron Gafny, Pascal Simonet, Edouard Jurkevitch, Zohar Pasternak
The ubiquity and transferability of soil makes it a resource for the forensic investigator, as it can provide a link between agents and scenes. However, the information contained in soils, such as chemical compounds, physical particles or biological entities, is seldom used in forensic investigations; due mainly to the associated costs, lack of available expertise, and the lack of soil databases. The microbial DNA in soil is relatively easy to access and analyse, having thus the potential to provide a powerful means for discriminating soil samples or linking them to a common origin...
October 6, 2016: Forensic Science International. Genetics
Dandan Li, Feilong Sun, Meriem Bourajjaj, Yinan Chen, Ebel H Pieters, Jian Chen, Joep B van den Dikkenberg, Bo Lou, Marcel G M Camps, Ferry Ossendorp, Wim E Hennink, Tina Vermonden, Cornelus F van Nostrum
Cancer vaccines are at present mostly based on tumor associated protein antigens but fail to elicit strong cell-mediated immunity in their free form. For protein-based vaccines, the main challenges to overcome are the delivery of sufficient proteins into the cytosol of dendritic cells (DCs) and processing by, and presentation through, the MHC class I pathway. Recently, we developed a cationic dextran nanogel in which a model antigen (ovalbumin, OVA) is reversibly conjugated via disulfide bonds to the nanogel network to enable redox-sensitive intracellular release...
October 17, 2016: Nanoscale
Xiaoru Zhang, Yan Yin, Zhenyi Lin, Yongxiang Han, Jian Hao, Liang Yuan, Kui Chen, Jinghua Chen, Shaofei Kong, Yunpeng Shan, Hui Xiao, Wen Tan
To quantify the physical/chemical properties, and the formation and growth processes of aerosol particles on mountainous regions in Southeast China, an intensive field campaign was conducted from April to July 2008 on the top of Mt. Huang (1840m above mean sea level). The average particle number concentration was 2.35×10(3)cm(-3), and the ultrafine particles (<0.1μm) represented 70.5% of the total particle number concentration. Excluding the accumulation mode particles, the average daytime particle number concentrations were prominently higher than those measured at nighttime, suggesting there was a diurnal pattern of changes between planetary boundary layer and free troposphere air...
October 12, 2016: Science of the Total Environment
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