200 research outputs found
Endovenous laser ablation: the role of intraluminal blood
AbstractObjectiveIn this histological study, the role of the intraluminal blood during endovenous laser ablation was assessed.MethodsIn 12 goats, 24 lateral saphenous veins were treated with a 1500-nm diode laser. Four goats were treated in an anti-Trendelenburg position (group 1). The next four goats were treated in a Trendelenburg position (group 2) and the remaining four goats in the Trendelenburg position with additional injection of tumescent liquid (group 3). Postoperatively, the veins were removed after 1 week and sent for histological examination. We measured the number of perforations. Vein wall necrosis and the perivenous tissue destruction were quantified using a graded scale.ResultsThe âcalculated total vein wall destructionâ was significantly higher in the third group (81.83%), as compared with groups one (61.25%) (p < 0.001) and two (65.92%) (p < 0.001). All three groups showed a significant difference in the perivenous tissue destruction scale (p < 0.001) with the lowest score occurring in the third group. Vein wall perforations were significantly more frequent in groups one and two as compared with the third group (T-test respectively p < 0.001, p = 0.02).ConclusionA higher intraluminal blood volume results in reduced total vein wall destruction. Injection of tumescent liquid prevents the perivenous tissue destruction and minimises the number of perforations
Highly efficient room temperature spin injection in a metal-insulator-semiconductor light emitting diode
We demonstrate highly efficient spin injection at low and room temperature in
an AlGaAs/GaAs semiconductor heterostructure from a CoFe/AlOx tunnel spin
injector. We use a double-step oxide deposition for the fabrication of a
pinhole-free AlOx tunnel barrier. The measurements of the circular polarization
of the electroluminescence in the Oblique Hanle Effect geometry reveal injected
spin polarizations of at least 24% at 80K and 12% at room temperature
Element geochemistry of Cherokee Group coals (Middle Pennsylanian) from south-central and southeastern Iowa
Middle Pennsylvanian Cherokee Group coals from south-central and southeastern Iowa are typical high-sulfur, high-ash coals. These coals have an arithmetic mean sulfur content of 5.8 percent and a mean ash content of 15.9 percent. Apparent rank for most samples is high-volatile C bituminous coal. The relatively high contents of sulfur and 23 other elements in Iowa Cherokee Group coals are related to near neutral pH conditions (6-8) in the depositional and early diagenetic environments, and to post-depositional epigenetic sphalerite/calcite/pyrite/ kaolinite/barite mineralization. Changes from an aluminosilicate- to a sulfide-element association for U, Mo, Cr, and V, and an increase in element content for U, Mo, Cr, V, Na, Mg, and K in stratigraphically higher coals are thought to be related to differences in depositional environments of the coal-associated rocks, which change from predominantly terrestrial in the Lower Cherokee Group, to predominantly marine in the upper part of the Upper Cherokee Group. Coals overlain by marine, phosphatic, black shale lithologies have the highest content of U, Mo, Ag, Sb, Se, and V
Voltage controlled spin injection in a (Ga,Mn)As/(Al,Ga)As Zener diode
The spin polarization of the electron current in a
p-(Ga,Mn)As-n-(Al,Ga)As-Zener tunnel diode, which is embedded in a
light-emitting diode, has been studied theoretically. A series of
self-consistent simulations determines the charge distribution, the band
bending, and the current-voltage characteristics for the entire structure. An
empirical tight-binding model, together with the Landauer- Buttiker theory of
coherent transport has been developed to study the current spin polarization.
This dual approach allows to explain the experimentally observed high magnitude
and strong bias dependence of the current spin polarization.Comment: Submitted to Phys. Rev. B Rapid Communication
Strong spin relaxation length dependence on electric field gradients
We discuss the influence of electrical effects on spin transport, and in
particular the propagation and relaxation of spin polarized electrons in the
presence of inhomogeneous electric fields. We show that the spin relaxation
length strongly depends on electric field gradients, and that significant
suppression of electron spin polarization can occur as a result thereof. A
discussion in terms of a drift-diffusion picture, and self-consistent numerical
calculations based on a Boltzmann-Poisson approach shows that the spin
relaxation length in fact can be of the order of the charge screening length.Comment: 4 pages, 3 figures, to be presented at PASPSI
Boosting the Figure Of Merit of LSPR-based refractive index sensing by phase-sensitive measurements
Localized surface plasmon resonances possess very interesting properties for
a wide variety of sensing applications. In many of the existing applications
only the intensity of the reflected or transmitted signals is taken into
account, while the phase information is ignored. At the center frequency of a
(localized) surface plasmon resonance, the electron cloud makes the transition
between in- and out-of-phase oscillation with respect to the incident wave.
Here we show that this information can experimentally be extracted by
performing phase-sensitive measurements, which result in linewidths that are
almost one order of magnitude smaller than those for intensity based
measurements. As this phase transition is an intrinsic property of a plasmon
resonance, this opens up many possibilities for boosting the figure of merit
(FOM) of refractive index sensing by taking into account the phase of the
plasmon resonance. We experimentally investigated this for two model systems:
randomly distributed gold nanodisks and gold nanorings on top of a continuous
gold layer and a dielectric spacer and observed FOM values up to 8.3 and 16.5
for the respective nanoparticles
Long-Read Sequencing to Unravel Complex Structural Variants of CEP78 Leading to Cone-Rod Dystrophy and Hearing Loss
Inactivating variants as well as a missense variant in the centrosomal CEP78 gene
have been identified in autosomal recessive cone-rod dystrophy with hearing loss
(CRDHL), a rare syndromic inherited retinal disease distinct from Usher syndrome.
Apart from this, a complex structural variant (SV) implicating CEP78 has been reported
in CRDHL. Here we aimed to expand the genetic architecture of typical CRDHL
by the identification of complex SVs of the CEP78 region and characterization of
their underlying mechanisms. Approaches used for the identification of the SVs are
shallow whole-genome sequencing (sWGS) combined with quantitative polymerase
chain reaction (PCR) and long-range PCR, or ExomeDepth analysis on whole-exome
sequencing (WES) data. Targeted or whole-genome nanopore long-read sequencing
(LRS) was used to delineate breakpoint junctions at the nucleotide level. For all SVs
cases, the effect of the SVs on CEP78 expression was assessed using quantitative
PCR on patient-derived RNA. Apart from two novel canonical CEP78 splice variants
and a frameshifting single-nucleotide variant (SNV), two SVs affecting CEP78 were
identified in three unrelated individuals with CRDHL: a heterozygous total gene deletion
of 235 kb and a partial gene deletion of 15 kb in a heterozygous and homozygous
state, respectively. Assessment of the molecular consequences of the SVs on patientâs
materials displayed a loss-of-function effect. Delineation and characterization of the 15-kb deletion using targeted LRS revealed the previously described complex CEP78
SV, suggestive of a recurrent genomic rearrangement. A founder haplotype was
demonstrated for the latter SV in cases of Belgian and British origin, respectively. The
novel 235-kb deletion was delineated using whole-genome LRS. Breakpoint analysis
showed microhomology and pointed to a replication-based underlying mechanism.
Moreover, data mining of bulk and single-cell human and mouse transcriptional datasets,
together with CEP78 immunostaining on human retina, linked the CEP78 expression
domain with its phenotypic manifestations. Overall, this study supports that the CEP78
locus is prone to distinct SVs and that SV analysis should be considered in a genetic
workup of CRDHL. Finally, it demonstrated the power of sWGS and both targeted
and whole-genome LRS in identifying and characterizing complex SVs in patients with
ocular diseases
Mutations in RNU7-1 weaken secondary RNA structure, induce MCP-1 and CXCL10 in CSF, and result in Aicardi-GoutiĂšres Syndrome with severe end-organ involvement
- âŠ