55 research outputs found
Measurement of polarization-transfer to bound protons in carbon and its virtuality dependence
We measured the ratio of the transverse to longitudinal
components of polarization transferred from electrons to bound protons in
by the process at the
Mainz Microtron (MAMI). We observed consistent deviations from unity of this
ratio normalized to the free-proton ratio,
, for both -
and -shell knocked out protons, even though they are embedded in averaged
local densities that differ by about a factor of two. The dependence of the
double ratio on proton virtuality is similar to the one for knocked out protons
from and , suggesting a universal behavior.
It further implies no dependence on average local nuclear density
Comparison of recoil polarization in the process for protons extracted from and shell
We present first measurements of the double ratio of the polarization
transfer components for knock-out protons from and
shells in measured by the reaction in quasi-elastic kinematics. The data are
compared to theoretical predictions in relativistic distorted-wave impulse
approximation. Our results show that differences between - and -shell
protons, observed when compared at the same initial momentum (missing momentum)
largely disappear when the comparison is done at the same proton virtuality. We
observe no density-dependent medium modifications for protons from and
shells with the same virtuality in spite of the large differences in the
respective nuclear densities
The influence of Fermi motion on the comparison of the polarization transfer to a proton in elastic and quasi-elastic scattering
A comparison between polarization-transfer to a bound proton in quasi-free
kinematics by the A knockout reaction and that in elastic
scattering off a free proton can provide information on the characteristics of
the bound proton. In the past the reported measurements have been compared to
those of a free proton with zero initial momentum. We introduce, for the first
time, expressions for the polarization-transfer components when the proton is
initially in motion and compare them to the H data measured at the Mainz
Microtron (MAMI). We show the ratios of the transverse () and longitudinal
() components of the polarization transfer in , to those of elastic scattering off a "moving proton", assuming
the proton's initial (Fermi) momentum equals the negative missing momentum in
the measured reaction. We found that the correction due to the proton motion is
up to 20\% at high missing momentum.
However the effect on the double ratio
is largely canceled out, as
shown for both H and C data. This implies that the kinematics is not
the primary cause for the deviations between quasi-elastic and elastic
scattering reported previously
Electrochemotherapy: technological advancements for efficient electroporation-based treatment of internal tumors
Contemporary Management of Locally Advanced and Recurrent Rectal Cancer: Views from the PelvEx Collaborative
Pelvic exenteration is a complex operation performed for locally advanced and recurrent pelvic cancers. The goal of surgery is to achieve clear margins, therefore identifying adjacent or involved organs, bone, muscle, nerves and/or vascular structures that may need resection. While these extensive resections are potentially curative, they can be associated with substantial morbidity. Recently, there has been a move to centralize care to specialized units, as this facilitates better multi-disciplinary care input. Advancements in pelvic oncology and surgical innovation have redefined the boundaries of pelvic exenterative surgery. Combined with improved neoadjuvant therapies, advances in diagnostics, and better reconstructive techniques have provided quicker recovery and better quality of life outcomes, with improved survival This article provides highlights of the current management of advanced pelvic cancers in terms of surgical strategy and potential future developments
Use of optical coherence tomography to predict visual outcome in parachiasmal meningioma
Electrochemotherapy: technological advancements for efficient electroporation-based treatment of internal tumors
Electrochemotherapy, a combination of high voltage electric pulses and of an anticancer drug, has been demonstrated to be highly effective in treatment of cutaneous and subcutaneous tumors. Unique properties of electrochemotherapy (e.g., high specificity for targeting cancer cells, high degree of localization of treatment effect, capacity for preserving the innate immune response and the structure of the extracellular matrix) are facilitating its wide spread in the clinics. Due to high effectiveness of electrochemotherapy in treatment of cutaneous and subcutaneous tumors regardless of histological origin, there are now attempts to extend its use to treatment of internal tumors. To advance the applicability of electrochemotherapy to treatment of internal solid tumors, new technological developments are needed that will enable treatment of these tumors in daily clinical practice. New electrodes through which electric pulses are delivered to target tissue need to be designed with the aim to access target tissue anywhere in the body. To increase the probability of complete tumor eradication, the electrodes have to be accurately positioned, first to provide an adequate extent of electroporation of all tumor cells and second not to damage critical healthy tissue or organs in its vicinity. This can be achieved by image guided insertion of electrodes that will enable accurate positioning of the electrodes in combination with patient-specific numerical treatment planning or using a predefined geometry of electrodes. In order to be able to use electrochemotherapy safely for treatment of internal tumors located in relative proximity of the heart (e.g., in case of liver metastases), the treatment must be performed without interfering with the heart's electrical activity. We describe recent technological advances, which allow treatment of liver and bone metastases, soft tissue sarcomas, brain tumors, and colorectal and esophageal tumors. The first clinical experiences in these novel application areas of electrochemotherapy are also described
Electrochemotherapy with bleomycin does not damage large blood vessels or other vital structures in porcine liver
Preoccupation with detail contributes to poor abstraction in women with anorexia nervosa.
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