285 research outputs found
Spin torque ferromagnetic resonance with magnetic field modulation
We demonstrate a technique of broadband spin torque ferromagnetic resonance
(ST-FMR) with magnetic field modulation for measurements of spin wave
properties in magnetic nanostructures. This technique gives great improvement
in sensitivity over the conventional ST-FMR measurements, and application of
this technique to nanoscale magnetic tunnel junctions (MTJs) reveals a rich
spectrum of standing spin wave eigenmodes. Comparison of the ST-FMR
measurements with micromagnetic simulations of the spin wave spectrum allows us
to explain the character of low-frequency magnetic excitations in nanoscale
MTJs.Comment: Also see: http://faculty.sites.uci.edu/krivorotovgroup
Radiation Heating of Primary Collimators at Ramping
A time-dependent temperature map is derived for the primary jaw of the momentum collimation system during the high transient loss period which is to occur at the beginning of the ramp of acceleration. An adequate margin factor is obtained for a loss of 5% of the nominal stored beam and for the nominal parabolic ramping curve
Boron adatom adsorption on graphene: A case study in computational chemistry methods for surface interactions
Though weak surface interactions and adsorption can play an important role in
plasma processing and materials science, they are not necessarily simple to
model. A boron adatom adsorbed on a graphene sheet serves as a case study for
how carefully one must select the correct technique from a toolbox of
computational chemistry methods. Using a variety of molecular dynamics
potentials and density functional theory functionals, we evaluate the
adsorption energy, investigate barriers to adsorption and migration, calculate
corresponding reaction rates, and show that a surprisingly high level of theory
may be necessary to verify that the system is described correctly
Magnetic phase transitions in Ta/CoFeB/MgO multilayers
We study thin films and magnetic tunnel junction nanopillars based on
Ta/CoFeB/MgO multilayers by electrical transport and
magnetometry measurements. These measurements suggest that an ultrathin
magnetic oxide layer forms at the CoFeB/MgO interface. At
approximately 160 K, the oxide undergoes a phase transition from an insulating
antiferromagnet at low temperatures to a conductive weak ferromagnet at high
temperatures. This interfacial magnetic oxide is expected to have significant
impact on the magnetic properties of CoFeB-based multilayers used in spin
torque memories
Возможности сфинктеросохраняющего лечения больных местно-распространенным первично-неоперабельным раком прямой кишки
The aim of this study was to compare results of sphincter-sparing operations (SSO) and abdominoperineal resections (APR) in patients undergoing combined treatment for unresectable locally-advanced rectal cancer.Methods. During September 2007 – January 2011 59 patients were enrolled. Original treatment scheme (RF patent № 2414936) was developed including radiotherapy 40 Gy in 4 Gy fractions, capecitabine 650 mg/m2 bid per os days 1-22, oxaliplatin 50 mg/m2 iv days 3, 10, 17, local hyperthermia on days 8, 12, 15, 17, 2 applications of metronidazole 10 g/m2 per rectum in a polymeric composition. Surgery was carried out following 6–8 weeks. SSO were carried out in 36 patients, APR in 23 patients. Study endpoints included 2-year OS and DFS, local recurrence and distant metastases rate, postoperative complications rate.Results. No significant differences in survival were observed: 2-year OS was 93.2 and 85.6 % (log- rank test p = 0.157) for SSO and APR groups accordingly, 2-year DFS was 88 and 71.9 % (log-rank test p = 0.064). Four (11.1 %) patients in SSO group and 4 (17.4 %) patients in APR group (р = 0.5511) developed local recurrences, 4 (11.1 %) and 7 (30.4 %) (р = 0.1293) developed distant metastases. Postoperative complications rate was 27.8 % (n = 10) and 39.1 % (n = 9) (р = 0.5181) in SSO and APR groups accordingly.Conclusions. Sphincter-sparting surgery is justified for unresectable locally advanced rectal cancer when technically feasible
Femtomolar detection of the heart failure biomarker NT-proBNP in artificial saliva using an immersible liquid-gated aptasensor with reduced graphene oxide
Measuring NT-proBNP biomarker is recommended for preliminary diagnostics of
the heart failure. Recent studies suggest a possibility of early screening of
biomarkers in saliva for non-invasive identification of cardiac diseases at the
point-of-care. However, NT-proBNP concentrations in saliva can be thousand time
lower than in blood plasma, going down to pg/mL level. To reach this level, we
developed a label-free aptasensor based on a liquid-gated field effect
transistor using a film of reduced graphene oxide monolayer (rGO-FET) with
immobilized NT-proBNP specific aptamer. We found that, depending on ionic
strength of tested solutions, there were different levels of correlation in
responses of electrical parameters of the rGO-FET aptasensor, namely, the Dirac
point shift and transconductance change. The correlation in response to
NT-proBNP was high for 1.6 mM phosphate-buffered saline (PBS) and zero for 16
mM PBS in a wide range of analyte concentrations, varied from 1 fg/mL to 10
ng/mL. The effects of transconductance and Dirac point shift in PBS solutions
of different concentrations are discussed. The biosensor exhibited a high
sensitivity for both transconductance (2 uS/decade) and Dirac point shift (2.3
mV/decade) in diluted PBS with the linear range from 10 fg/mL to 1 pg/mL. The
aptasensor performance has been also demonstrated in undiluted artificial
saliva with the achieved limit of detection down to 41 fg/mL (~4.6 fM)
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