149 research outputs found
Polarized Proton Beams from Laser-induced Plasmas
We report on the concept of an innovative source to produce polarized
proton/deuteron beams of a kinetic energy up to several GeV from a laser-driven
plasma accelerator. Spin effects have been implemented into the PIC simulation
code VLPL to make theoretical predictions about the behavior of proton spins in
laser-induced plasmas. Simulations of spin-polarized targets show that the
polarization is conserved during the acceleration process. For the experimental
realization, a polarized HCl gas-jet target is under construction using the
fundamental wavelength of a Nd:YAG laser system to align the HCl bonds and
simultaneously circular polarized light of the fifth harmonic to
photo-dissociate, yielding nuclear polarized H atoms. Subsequently, their
degree of polarization is measured with a Lamb-shift polarimeter. The final
experiments, aiming at the first observation of a polarized particle beam from
laser-generated plasmas, will be carried out at the 10 PW laser system SULF at
SIOM/Shanghai.Comment: 7 pages, 7 figure
Stark shift and parity non-conservation for near-degenerate states of xenon
We identify a pair of near-degenerate states of opposite parity in atomic Xe,
the 5p^5 10s \,\, ^2[3/2]_2^o at cm and 5p^5 6f
\,\, ^2[5/2]_2 at cm, for which parity- and
time-odd effects are expected to be enhanced by the small energy separation. We
present theoretical calculations which indicate narrow widths for both states
and we report a calculated value for the weak matrix element, arising from
configuration mixing, of Hz for Xe. In addition, we measured
the Stark effect of the and
() states. The Stark-shift of the states
is observed to be negative, revealing the presence of nearby states at
higher energies, which have not been observed before. The Stark-shift
measurements imply an upper limit on the weak matrix element of Hz
for the near-degenerate states (10s \,\, ^2[3/2]_2^o and 6f \,\,
^2[5/2]_2), which is in agreement with the presented calculations.Comment: 11 pages, 6 figure
Molecular profiling and genomic microarrays in prostate cancer
In the present review article a global approach regarding the usefulness of genomic microarrays in prostate cancer management, is attempted. Cancer is a multistep process of mutations in key regulatory genes and epigenetic alterations that result in loss of balanced gene expression. A complete knowledge of the interaction between the genetic variability of the neoformation (tumor profiling) and the genetic variability of the host (inherited genome profiling), will be able to determine the better strategy against the cancer and the less toxicity for the patient. Alterations in the sequence of the hormone binding domain of the androgen receptor as well as mutations in some genes, determine radioresistance and resistance or sensitivity to some chemotherapeutic drugs. New therapies using monoclonal antibodies directed against specific extracellular binding domains of some receptors are based on molecular alterations observed in tumors.В обзоре обсуждается целесообразность применения геномных микрочипов для выявления рака предстательной железы.
Рак является многоэтапным процессом мутаций в ключевых регуляторных генах и эпигенетических изменений, приводящих
к утрате сбалансированной экспрессии генов. Фундаментальные знания о взаимосвязи между генетической вариабельностью
опухолевых клеток (молекулярном профиле опухоли) и генетической вариабельностью хозяина (наследуемый геномный
профиль) позволит выбрать наилучшую стратегию противоопухолевой терапии при низкой токсичности таковой. Изменения
последовательности гормонсвязывающего домена рецептора андрогена наряду с мутациями некоторых генов определяют
устойчивость к лучевой терапии и устойчивость или чувствительность к ряду химиопрепаратов. Новые виды терапии
с использованием моноклональных антител против специфичных внеклеточных связывающих доменов ряда рецепторов
основаны на данных о молекулярных особенностях новообразований
Nanosecond control and high-density production of spin-polarized hydrogen atoms
We demonstrate directly the nanosecond-timescale production of
spin-polarized hydrogen (SPH) atoms from photodissociation of thermal HBr
molecules, and the spin-state and Doppler-resolved detection using polarized
fluorescence at 121.6 nm, without requiring hyperfine resolution. These
techniques allow a variety of spin-dependent, nanosecond pump-probe experiments with SPH, which were not previously realizable. The potential of
surpassing the SPH densities and production rates of current techniques is
discussed
Formation and interactions of cold and ultracold molecules: new challenges for interdisciplinary physics
Progress on researches in the field of molecules at cold and ultracold
temperatures is reported in this review. It covers extensively the experimental
methods to produce, detect and characterize cold and ultracold molecules
including association of ultracold atoms, deceleration by external fields and
kinematic cooling. Confinement of molecules in different kinds of traps is also
discussed. The basic theoretical issues related to the knowledge of the
molecular structure, the atom-molecule and molecule-molecule mutual
interactions, and to their possible manipulation and control with external
fields, are reviewed. A short discussion on the broad area of applications
completes the review.Comment: to appear in Reports on Progress in Physic
European Association of Urology Guidelines Office Rapid Reaction Group: An Organisation-wide Collaborative Effort to Adapt the European Association of Urology Guidelines Recommendations to the Coronavirus Disease 2019 Era
The coronavirus disease 2019 (COVID-19) pandemic is unlike anything seen before by modern science-based medicine. As a scientific society, the European Association of Urology, via the guidelines, section offices, and the European Urology family of journals, we believe that it is important that we try to support urologists in this difficult situation. We aim to do this by providing tools that can facilitate decision making with the goal to minimise the impact and risks for both patients and health professionals delivering urological care, whenever possible, although it is clear that it is not always possible to mitigate them entirely. We hope that these revised recommendations will fill an important urological practice void and assist urologist surgeons across the globe as they do their very best to deal with the crisis of our generation
Cold and Ultracold Molecules: Science, Technology, and Applications
This article presents a review of the current state of the art in the
research field of cold and ultracold molecules. It serves as an introduction to
the Special Issue of the New Journal of Physics on Cold and Ultracold Molecules
and describes new prospects for fundamental research and technological
development. Cold and ultracold molecules may revolutionize physical chemistry
and few body physics, provide techniques for probing new states of quantum
matter, allow for precision measurements of both fundamental and applied
interest, and enable quantum simulations of condensed-matter phenomena.
Ultracold molecules offer promising applications such as new platforms for
quantum computing, precise control of molecular dynamics, nanolithography, and
Bose-enhanced chemistry. The discussion is based on recent experimental and
theoretical work and concludes with a summary of anticipated future directions
and open questions in this rapidly expanding research field.Comment: 82 pages, 9 figures, review article to appear in New Journal of
Physics Special Issue on Cold and Ultracold Molecule
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