510 research outputs found
Electromagnetic properties of neutrinos
A short review on electromagnetic properties of neutrinos is presented. In
spite of many efforts in the theoretical and experimental studies of neutrino
electromagnetic properties, they still remain one of the main puzzles related
to neutrinos.Comment: The talk presented by A.Studenikin at the International Conference on
Topics in Astroparticle and Underground Physics, Rome (Italy), July 1-5, 200
Protocell Communication Through the Eyes of Synthetic Organic Chemists
The bottom-up fabrication of synthetic cells (protocells) from molecules and materials, is a major challenge of modern chemistry. A significant breakthrough has been the engineering of protocells capable of chemical communication using bio- derived molecules and ex situ stabilised cell machineries. These, however, suffer from short shelf-lives, high costs, and require mild aqueous conditions. In this Concept Article we analyse the chemistry at the heart of protocell communication to highlight new opportunities for synthetic chemists in protocell engineer- ing. Specifically, we (i) categorise the main bio-derived chemical communication machineries in enzyme cascades, DNA strand displacement, and gene-mediated communication; (ii) review the chemistries of these signal transduction machineries; and (iii) introduce new types of bio-inspired, fully synthetic artificial enzymes to replace their natural counterparts. Developing protocells that incorporate synthetic analogues of bio-derived signal transduction machineries will improve the robustness, stability, and versatility of protocells, and broaden their applications to highly strategic fields such as photocatalysis and fine chemicals production
Treatment of squamous cell carcinoma of the anal canal: A new strategies with anti-EGFR therapy and immunotherapy
The incidence of squamous cell carcinoma of the anal canal (SCAC) is increasing in both sexes but the standard treatment remains that of 20 years ago. However, interesting data have recently emerged on the use of anti-epidermal growth factor receptor (EGFR) agents and immunotherapy in advanced disease. Thus, new avenues of research are opening up that will hopefully lead to more effective therapeutic strategies. We provide an overview of the latest studies published on this tumor and discuss the possible future therapeutic options for combination therapy, anti-EGFR treatment and radiotherapy
Oscillatons revisited
In this paper, we study some interesting properties of a spherically
symmetric oscillating soliton star made of a real time-dependent scalar field
which is called an oscillaton. The known final configuration of an oscillaton
consists of a stationary stage in which the scalar field and the metric
coefficients oscillate in time if the scalar potential is quadratic. The
differential equations that arise in the simplest approximation, that of
coherent scalar oscillations, are presented for a quadratic scalar potential.
This allows us to take a closer look at the interesting properties of these
oscillating objects. The leading terms of the solutions considering a quartic
and a cosh scalar potentials are worked in the so called stationary limit
procedure. This procedure reveals the form in which oscillatons and boson stars
may be related and useful information about oscillatons is obtained from the
known results of boson stars. Oscillatons could compete with boson stars as
interesting astrophysical objects, since they would be predicted by scalar
field dark matter models.Comment: 10 pages REVTeX, 10 eps figures. Updated files to match version
published in Classical and Quantum Gravit
ICER is requisite for Th17 differentiation.
Inducible cAMP early repressor (ICER) has been described as a transcriptional repressor isoform of the cAMP response element modulator (CREM). Here we report that ICER is predominantly expressed in Th17 cells through the IL-6-STAT3 pathway and binds to the Il17a promoter, where it facilitates the accumulation of the canonical enhancer RORγt. In vitro differentiation from naive ICER/CREM-deficient CD4(+) T cells to Th17 cells is impaired but can be rescued by forced overexpression of ICER. Consistent with a role of Th17 cells in autoimmune and inflammatory diseases, ICER/CREM-deficient B6.lpr mice are protected from developing autoimmunity. Similarly, both anti-glomerular basement membrane-induced glomerulonephritis and experimental encephalomyelitis are attenuated in ICER/CREM-deficient mice compared with their ICER/CREM-sufficient littermates. Importantly, we find ICER overexpressed in CD4(+) T cells from patients with systemic lupus erythematosus. Collectively, our findings identify a unique role for ICER, which affects both organ-specific and systemic autoimmunity in a Th17-dependent manner
Can dark matter be a Bose-Einstein condensate?
We consider the possibility that the dark matter, which is required to
explain the dynamics of the neutral hydrogen clouds at large distances from the
galactic center, could be in the form of a Bose-Einstein condensate. To study
the condensate we use the non-relativistic Gross-Pitaevskii equation. By
introducing the Madelung representation of the wave function, we formulate the
dynamics of the system in terms of the continuity equation and of the
hydrodynamic Euler equations. Hence dark matter can be described as a
non-relativistic, Newtonian Bose-Einstein gravitational condensate gas, whose
density and pressure are related by a barotropic equation of state. In the case
of a condensate with quartic non-linearity, the equation of state is polytropic
with index . To test the validity of the model we fit the Newtonian
tangential velocity equation of the model with a sample of rotation curves of
low surface brightness and dwarf galaxies, respectively. We find a very good
agreement between the theoretical rotation curves and the observational data
for the low surface brightness galaxies. The deflection of photons passing
through the dark matter halos is also analyzed, and the bending angle of light
is computed. The bending angle obtained for the Bose-Einstein condensate is
larger than that predicted by standard general relativistic and dark matter
models. Therefore the study of the light deflection by galaxies and the
gravitational lensing could discriminate between the Bose-Einstein condensate
dark matter model and other dark matter models.Comment: 20 pages, 7 figures, accepted for publication in JCAP, references
adde
Electromagnetic Form Factors of a Massive Neutrino
Electromagnetic form factors of a massive neutrino are studied in a minimally
extended standard model in an arbitrary gauge and taking into account
the dependence on the masses of all interacting particles. The contribution
from all Feynman diagrams to the charge, magnetic, and anapole form factors, in
which the dependence on the masses of all particles as well as on gauge
parameters is accounted for exactly, are obtained for the first time in
explicit form. The asymptotic behavior of the magnetic form factor for large
negative squares of the momentum of an external photon is analyzed and
expression for the anapole moment of a massive neutrino is derived. The results
are generalized to the case of mixing between various generations of the
neutrino. Explicit expressions are obtained for the charge, magnetic, and
electric dipole and anapole transition form factors as well as for the
transition electric dipole moment.Comment: 16 pares with 5 figures in pdf forma
On the thermal footsteps of Neutralino relic gases
Current literature suggests that neutralinos are the dominant cold dark
matter particle species. Assuming the microcanonical definition of entropy, we
examine the local entropy per particle produced between the ``freeze out'' era
to the present. An ``entropy consistency'' criterion emerges by comparing this
entropy with the entropy per particle of actual galactic structures given in
terms of dynamical halo variables. We apply this criterion to the cases when
neutralinos are mosly b-inos and mostly higgsinos, in conjunction with the
usual ``abundance'' criterion requiring that present neutralino relic density
complies with 0.1 < \Omega_{\chic{\tilde\chi^0_1}} < 0.3 for .
The joint application of both criteria reveals that a better fitting occurs for
the b-ino channels, hence the latter seem to be favoured over the higgsino
channels. The suggested methodology can be applied to test other annihilation
channels of the neutralino, as well as other particle candidates of thermal
gases relics.Comment: LaTex AIP style, 8 pages including 1 figure. Final version to appear
in Proceedings of the Mexican School of Astrophysics (EMA), Guanajuato,
M\'exico, July 31 - August 7, 200
Image-guided multisession radiosurgery of skull base meningiomas
Background: The efficacy of single-session stereotactic radiosurgery (sSRS) for the treatment of intracranial meningioma is widely recognized. However, sSRS is not always feasible in cases of large tumors and those lying close to critically radiation-sensitive structures. When surgery is not recommended, multi-session stereotactic radiosurgery (mSRS) can be applied. Even so, the efficacy and best treatment schedule of mSRS are not yet established. The aim of this study is to validate the role of mSRS in the treatment of skull base meningiomas. Methods: A retrospective analysis of patients with skull base meningiomas treated with mSRS (two to five fractions) at the University of Messina, Italy, from 2008 to 2018, was conducted. Results: 156 patients met the inclusion criteria. The median follow-up period was 36.2 \ub1 29.3 months. Progression-free survival at 2-, 5-, and 10-years was 95%, 90%, and 80.8%, respectively. There were no new visual or motor deficits, nor cranial nerves impairments, excluding trigeminal neuralgia, which was reported by 5.7% of patients. One patient reported carotid occlusion and one developed brain edema. Conclusion: Multisession radiosurgery is an effective approach for skull base meningiomas. The long-term control is comparable to that obtained with conventionally-fractionated radiotherapy, while the toxicity rate is very limited
- …