535 research outputs found
THE BEAM ENVELOPE CONTROL IN SC LINAC FOR THE PROTON RADIOTHERAPY
Abstract Proton cancer therapy is conventionally based on normal conducting synchrotrons and cyclotrons. The high electrical power consumption and especial devices necessary to energy variation are main problems of such facilities. Superconducting linacs based on short identical independently phased cavities have a seriously progress and it's development allow to propose their using for medical application. High accelerating gradient and small capacity losses nearly 10 -4 W/m are main advantages in advance of normal conducting facilities, the energy variation can be realized by means of RF field amplitude and phase variation in a number of cavities. Besides linac structures are lack of unwieldy magnetic system, simplicity of input and output of particles and high current densities. The parameters choose and the optimization for SC linac structure with energy up to 240 MeV and envelope control will discuss in this paper. The simulation was done using BEAMDULAC-SCL cod
Significant delay of lethal outcome in cancer patients due to peroral administration of Bacillus oligonitrophilus KU-1.
Treatment of cancer patients remains a serious medical problem and the development of alternative treatment strategies is therefore of great importance. In this connection, we developed a new bacterial-based, anticancer method. Ten cancer patients (three males, seven females) were involved in this study. Bacterial suspension of stationary phase Bacillus oligonitrophilus KU-1 was used as a remedy for peroral administration. In five patients, side effects (sicchasia, slight blood, and intracranial pressure gain) were detected, but all patients showed significant delay of lethal outcome without serious side effects. In conclusion, the suggested method was, in our opinion, a good alternative to conventional chemo- and radiotherapy techniques. In order to evaluate its efficiency for various tumors, a double-blind, placebo-controlled, multicenter study is needed
Salerno's model of DNA reanalysed: could solitons have biological significance?
We investigate the sequence-dependent behaviour of localised excitations in a
toy, nonlinear model of DNA base-pair opening originally proposed by Salerno.
Specifically we ask whether ``breather'' solitons could play a role in the
facilitated location of promoters by RNA polymerase. In an effective potential
formalism, we find excellent correlation between potential minima and {\em
Escherichia coli} promoter recognition sites in the T7 bacteriophage genome.
Evidence for a similar relationship between phage promoters and downstream
coding regions is found and alternative reasons for links between AT richness
and transcriptionally-significant sites are discussed. Consideration of the
soliton energy of translocation provides a novel dynamical picture of sliding:
steep potential gradients correspond to deterministic motion, while ``flat''
regions, corresponding to homogeneous AT or GC content, are governed by random,
thermal motion. Finally we demonstrate an interesting equivalence between
planar, breather solitons and the helical motion of a sliding protein
``particle'' about a bent DNA axis.Comment: Latex file 20 pages, 5 figures. Manuscript of paper to appear in J.
Biol. Phys., accepted 02/09/0
Antitumor features of Bacillus oligonitrophilus KU-1 strain
Chemotherapy and radiotherapy remain mostly palliative methods for metastatic cancer treatment. Limitations in efficacy and safety of established treatments continue to underline the need for improved treatments for malignancy. Results with some probiotics with antitumor activity have been promising. Here, we report that oral reception of Bacillus oligonitrophilus KU-1 resulted in the prolongation of lives in cancer patients with terminal prognosis and stabilization of cancer growth. The theoretical basis for the phenomena observed is discussed
Measurement of the B0_s semileptonic branching ratio to an orbitally excited D_s** state, Br(B0_s -> Ds1(2536) mu nu)
In a data sample of approximately 1.3 fb-1 collected with the D0 detector
between 2002 and 2006, the orbitally excited charm state D_s1(2536) has been
observed with a measured mass of 2535.7 +/- 0.6 (stat) +/- 0.5 (syst) MeV via
the decay mode B0_s -> D_s1(2536) mu nu X. A first measurement is made of the
branching ratio product Br(b(bar) -> D_s1(2536) mu nu X).Br(D_s1(2536)->D*
K0_S). Assuming that D_s1(2536) production in semileptonic decay is entirely
from B0_s, an extraction of the semileptonic branching ratio Br(B0_s ->
D_s1(2536) mu nu X) is made.Comment: 7 pages, 2 figures, LaTeX, version with minor changes as accepted by
Phys. Rev. Let
Measurement of the t-channel single top quark production cross section
The D0 collaboration reports direct evidence for electroweak production of
single top quarks through the t-channel exchange of a virtual W boson. This is
the first analysis to isolate an individual single top quark production
channel. We select events containing an isolated electron or muon, missing
transverse energy, and two, three or four jets from 2.3 fb^-1 of ppbar
collisions at the Fermilab Tevatron Collider. One or two of the jets are
identified as containing a b hadron. We combine three multivariate techniques
optimized for the t-channel process to measure the t- and s-channel cross
sections simultaneously. We measure cross sections of 3.14 +0.94 -0.80 pb for
the t-channel and 1.05 +-0.81 pb for the s-channel. The measured t-channel
result is found to have a significance of 4.8 standard deviations and is
consistent with the standard model prediction.Comment: 7 pages, 6 figure
Search for new fermions ("quirks") at the Fermilab Tevatron Collider
We report results of a search for particles with anomalously high ionization
in events with a high transverse energy jet and large missing transverse energy
in fb of integrated luminosity collected by the D0 experiment at
the Fermilab Tevatron collider. Production of such particles
(quirks) is expected in scenarios with extra QCD-like {\it SU(N)} sectors, and
this study is the first dedicated search for such signatures. We find no
evidence of a signal and set a lower mass limit of 107 ~GeV for the mass of a
charged quirk with strong dynamics scale in the range from 10 keV to
1 MeV.Comment: submitted to Phys. Rev. Letter
Design, Characteristics and Dynamic Properties of Mobile Plunger based Frequency Tuning System for Coaxial Half Wave Resonators
The practical realization of a prototype of the frequency tuning system FTS for coaxial half wave cavities HWR for the Nuclotron based Ion Collider fAcility NICA in jector is presented. The impact of FTS on electromagnetic parameters of copper HWR prototype is experimentally stud ied and discussed. The most important parameters like tun ing range, tuning sensitivity, the dependence of the resonant frequency on the position of the plungers are estimated. The effective operation algorithms of the proposed FTS are dis cussed and analyzed. The dynamic characteristics of FTS are investigated and showed the ability to adjust the frequency with an accuracy of about 70 H
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