44 research outputs found
The transition from the adiabatic to the sudden limit in core level photoemission: A model study of a localized system
We consider core electron photoemission in a localized system, where there is
a charge transfer excitation. The system is modelled by three electron levels,
one core level and two outer levels. The model has a Coulomb interaction
between these levels and the continuum states into which the core electron is
emitted. The model is simple enough to allow an exact numerical solution, and
with a separable potential an analytic solution. We calculate the ratio
r(omega) between the weights of the satellite and the main peak as a function
of the photon energy omega. The transition from the adiabatic to the sudden
limit takes place for quite small photoelectron kinetic energies. For such
small energies, the variation of the dipole matrix element is substantial and
described by the energy scale Ed. Without the coupling to the photoelectron,
the corresponding ratio r0(omega) is determined by Ed and the satellite
excitation energy dE. When the interaction potential with the continuum states
is introduced, a new energy scale Es=1/(2Rs^2) enters, where Rs is a length
scale of the interaction potential. At threshold there is typically a (weak)
constructive interference between intrinsic and extrinsic contributions, and
the ratio r(omega)/r0(omega) is larger than its limiting value for large omega.
The interference becomes small or weakly destructive for photoelectron energies
of the order Es. For larger energies r(omega)/r0(omega) therefore typically has
a weak undershoot. If this undershoot is neglected, r(omega)/r0(omega) reaches
its limiting value on the energy scale Es.Comment: 18 pages, latex2e, 13 eps figure
Mechanical performance and healing patterns of the novel sirolimus-eluting bioresorbable Fantom scaffold: 6-month and 9-month follow-up by optical coherence tomography in the FANTOM II study
Objectives We aimed to evaluate the mechanical properties
and healing patterns 6 and 9 months after implantation of the
sirolimus-eluting Fantom bioresorbable scaffold (BRS).
Background The Fantom BRS (Reva Medical, San Diego,
USA) has differentiating properties including radiopacity,
strut thickness of 125 ”m, high expansion capacity and
has demonstrated favourable mid-term clinical and
angiographic outcomes.
Methods and results FANTOM II was a prospective,
single arm study with implantation of the Fantom BRS
in 240 patients with stable angina pectoris. Guidance by
optical coherence tomography (OCT) was encouraged and
was repeated at 6-month (cohort A) or 9-month follow-up
(cohort B). Matched baseline and follow-up OCT recordings
were available in 152 patients. In-scaffold mean lumen
area in cohort A was 6.8±1.7mm2
and 5.7±1.4mm2
at baseline and follow-up (p<0.0001) and was
7.2±1.6mm2
and 5.6±1.4mm2
in cohort B (p<0.0001).
Mean scaffold area remained stable from 7.1±1.5mm2
at baseline to 7.2±1.4mm2
at 6 months (p=0.12), and
from 7.4±1.5mm2
to 7.3±1.4mm2
at 9 months. Strut
malapposition was median 0.8 (IQR 0.0;3.5)% and 1.8 (IQR
0.3;6.0)% at baseline and was 0.0 (IQR 0.0;0.0)% in both
groups at 6-month and 9-month follow-up. Strut tissue
coverage was 98.1 (IQR 95.9;99.4)% at 6 months and
98.9 (IQR 98.3;100.0)% at 9 months.
Conclusions The novel Fantom BRS had favourable
healing patterns at 6-month and 9-month follow-up as
malapposition was effectively resolved and strut coverage
was almost complete. The scaffold remained stable
through follow-up with no signs of systematic late recoil
History of clinical transplantation
How transplantation came to be a clinical discipline can be pieced together by perusing two volumes of reminiscences collected by Paul I. Terasaki in 1991-1992 from many of the persons who were directly involved. One volume was devoted to the discovery of the major histocompatibility complex (MHC), with particular reference to the human leukocyte antigens (HLAs) that are widely used today for tissue matching.1 The other focused on milestones in the development of clinical transplantation.2 All the contributions described in both volumes can be traced back in one way or other to the demonstration in the mid-1940s by Peter Brian Medawar that the rejection of allografts is an immunological phenomenon.3,4 © 2008 Springer New York
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
Nanobubbles and their precursor layer at the interface of water against a hydrophobic substrate
Neutron reflectivity experiments on the interface of pure D2O against thin films of perdeuterated polystyrene d PS spin coated onto silicon blocks were performed to study the intrinsic structure of the interface of water against hydrophobic substrates. The experiments reveal nonvanishing scattering contrast at the polymer water interface, although the two materials d PS and D2O have closely similar scattering length densities. Organic nondeuterated contaminants or macroscopic air bubbles trapped at the polymer water interface can be ruled out as the origin of this observation. From a systematic study of this system, it is concluded that the source of the nonvanishing contrast is a depletion of water in the boundary layer against the hydrophobic surface. It is conjectured that this depletion layer represents a precursor layer of submicroscopic gas bubbles recently observed by Tyrrell and Attard. The existence of such gas nanobubbles in the present system is confirmed by atomic force microscopy AFM of the surface of d PS coatings in contact with bulk water. The thickness of the precursor gas layer as determined by neutron reflectometry is 2 5 nm, depending on the level of air saturation of the water sample and on the time elapsed after contacting it with the hydrophobic surfac