47 research outputs found
Symptomatology and Anatomy of Stemgrooving (Legno Riccio) 1n the Grape Vine
External and anatomical differences between organs affected and unaffected by stemgrooving were studied on the wine grape cultivar Chenin blanc and the table grape cultivars Barlinka and Almeria. Cultivar susceptibility, graft transmissibility as well as the effect of the disease on the percentage of take and growth in: the nursery were studied. The probability of an association with other virus diseases was considered. Abnormal behaviour of the vascular cambium of infected vines gave rise to hypertrophy, hyperplasia, hypoplasia and parenchymatoses in the secondary xylem and phloem. In diseased tissues dift'erentiation of pbeDogen proceeded abnormally deep into the phloem rays. Graft transmission was detected anatomically within six months. The disease was found in all the vine growing districts of the Western Cape. Anatomical.studies showed that the disease had been present for many years. A negative effect on the percentage of t:'tKe and growth in the nursery was, recorded. A probable-relationship with corky bark was indicated anatomically and by indexing with LN33
Electric and Magnetic Tuning Between the Trivial and Topological Phases in InAs/GaSb Double Quantum Wells
Among the theoretically predicted two-dimensional topological insulators,
InAs/GaSb double quantum wells (DQWs) have a unique double-layered structure
with electron and hole gases separated in two layers, which enables tuning of
the band alignment via electric and magnetic fields. However, the rich
trivial-topological phase diagram has yet to be experimentally explored. We
present an in situ and continuous tuning between the trivial and topological
insulating phases in InAs/GaSb DQWs through electrical dual-gating.
Furthermore, we show that an in-plane magnetic field shifts the electron and
hole bands relatively to each other in momentum space, functioning as a
powerful tool to discriminate between the topologically distinct states
Evaluation of ear, nose, and throat-screening in liver transplantation candidates:A retrospective cohort study
Background:Patients with end-stage liver disease can be treated with a liver transplantation (LT). Before listing, candidates are subjected to a screening procedure according to the EASL Clinical Practice Guidelines for LT. In our hospital, this includes an ear, nose, and throat (ENT) examination, directed towards the identification of (asymptomatic) infections and head and neck malignancies.Methods:We retrospectively reviewed all ENT screening examinations in LT candidates from 2007 to 2022. The screening consisted of a visit to the ENT outpatient clinic combined with sinus radiography.Results:ENT screening was performed in 1099 patients. Sixty-one cases were identified, either diagnosed with an infection (n = 58, almost exclusively sinusitis) or a neoplasm (n = 3, of which two malignancies). With binary logistic regression, we could not identify significant risk factors for diagnosing sinusitis. 711 patients underwent LT. After LT, two patients developed a novel malignancy of the head and neck area, while 14 patients were diagnosed with sinusitis, two of the latter already showed opacification on sinus radiography during screening. Despite immunosuppressive drugs, no complicated sinusitis was observed.Conclusion:Sinusitis or a neoplasm was diagnosed in almost 6% in a large cohort of LT candidates. Although almost a third of sinusitis patients were not treated accordingly, we did not observe any complicated sinusitis after LT. A more conservative approach to sinusitis may therefore be justified in LT candidates, especially in asymptomatic cases. At our institution, we aim to refer only those patients with specific ENT complaintsimage.This study aimed to evaluate the outcome of routine ear, nose, and throat screening in a large cohort of liver transplantation candidates. Note that, 6% were diagnosed with either sinusitis or a neoplasm. We did not observe any complicated sinusitis after transplantation. A more conservative approach may therefore be justified, especially in asymptomatic cases.imag
Giant spin-orbit splitting in inverted InAs/GaSb double quantum wells
Transport measurements in inverted InAs/GaSb quantum wells reveal a giant
spin-orbit splitting of the energy bands close to the hybridization gap. The
splitting results from the interplay of electron-hole mixing and spin-orbit
coupling, and can exceed the hybridization gap. We experimentally investigate
the band splitting as a function of top gate voltage for both electron-like and
hole-like states. Unlike conventional, noninverted two-dimensional electron
gases, the Fermi energy in InAs/GaSb can cross a single spin-resolved band,
resulting in full spin-orbit polarization. In the fully polarized regime we
observe exotic transport phenomena such as quantum Hall plateaus evolving in
steps and a non-trivial Berry phase
A non-invasive method for nanoscale electrostatic gating of pristine materials
Electrostatic gating is essential for defining and control of semiconducting
devices. However, nano-fabrication processes required for depositing gates
inevitably degrade the pristine quality of the material of interest. Examples
of materials that suffer from such degradation include ultra-high mobility
GaAs/AlGaAs two-dimensional electron gases (2DEGs), graphene, topological
insulators, and nanowires. To preserve the pristine material properties, we
have developed a flip-chip setup where gates are separated from the material by
a vacuum, which allows nanoscale electrostatic gating of the material without
exposing it to invasive nano-processing. An additional benefit is the vacuum
between gates and material, which, unlike gate dielectrics, is free from charge
traps. We demonstrate the operation and feasibility of the flip-chip setup by
achieving quantum interference at integer quantum Hall states in a
Fabry-P\'erot interferometer based on a GaAs/AlGaAs 2DEG. Our results pave the
way for the study of exotic phenomena including fragile fractional quantum Hall
states by preserving the high quality of the material.Comment: 25 pages including Supporting Informatio
Evaluation of ear, nose, and throat-screening in liver transplantation candidates:A retrospective cohort study
Background:Patients with end-stage liver disease can be treated with a liver transplantation (LT). Before listing, candidates are subjected to a screening procedure according to the EASL Clinical Practice Guidelines for LT. In our hospital, this includes an ear, nose, and throat (ENT) examination, directed towards the identification of (asymptomatic) infections and head and neck malignancies.Methods:We retrospectively reviewed all ENT screening examinations in LT candidates from 2007 to 2022. The screening consisted of a visit to the ENT outpatient clinic combined with sinus radiography.Results:ENT screening was performed in 1099 patients. Sixty-one cases were identified, either diagnosed with an infection (n = 58, almost exclusively sinusitis) or a neoplasm (n = 3, of which two malignancies). With binary logistic regression, we could not identify significant risk factors for diagnosing sinusitis. 711 patients underwent LT. After LT, two patients developed a novel malignancy of the head and neck area, while 14 patients were diagnosed with sinusitis, two of the latter already showed opacification on sinus radiography during screening. Despite immunosuppressive drugs, no complicated sinusitis was observed.Conclusion:Sinusitis or a neoplasm was diagnosed in almost 6% in a large cohort of LT candidates. Although almost a third of sinusitis patients were not treated accordingly, we did not observe any complicated sinusitis after LT. A more conservative approach to sinusitis may therefore be justified in LT candidates, especially in asymptomatic cases. At our institution, we aim to refer only those patients with specific ENT complaintsimage.This study aimed to evaluate the outcome of routine ear, nose, and throat screening in a large cohort of liver transplantation candidates. Note that, 6% were diagnosed with either sinusitis or a neoplasm. We did not observe any complicated sinusitis after transplantation. A more conservative approach may therefore be justified, especially in asymptomatic cases.imag
Spin-orbit interaction in a dual gated InAs/GaSb quantum well
Spin-orbit interaction is investigated in a dual gated InAs/GaSb quantum
well. Using an electric field the quantum well can be tuned between a single
carrier regime with exclusively electrons as carriers and a two-carriers regime
where electrons and holes coexist. Spin-orbit interaction in both regimes
manifests itself as a beating in the Shubnikov-de Haas oscillations. In the
single carrier regime the linear Dresselhaus strength is characterized by
28.5 meV and the Rashba coefficient is tuned from 75 to
53 meV by changing the electric field. In the two-carriers regime the spin
splitting shows a nonmonotonic behavior with gate voltage, which is consistent
with our band structure calculations
Host-plant species conservatism and ecology of a parasitoid fig wasp genus (Chalcidoidea; Sycoryctinae; Arachonia)
Parasitoid diversity in terrestrial ecosystems is enormous. However, ecological processes underpinning their evolutionary diversification in association with other trophic groups are still unclear. Specialisation and interdependencies among chalcid wasps that reproduce on Ficus presents an opportunity to investigate the ecology of a multi-trophic system that includes parasitoids. Here we estimate the host-plant species specificity of a parasitoid fig wasp genus that attacks the galls of non-pollinating pteromalid and pollinating agaonid fig wasps. We discuss the interactions between parasitoids and the Ficus species present in a forest patch of Uganda in context with populations in Southern Africa. Haplotype networks are inferred to examine intraspecific mitochondrial DNA divergences and phylogenetic approaches used to infer putative species relationships. Taxonomic appraisal and putative species delimitation by molecular and morphological techniques are compared. Results demonstrate that a parasitoid fig wasp population is able to reproduce on at least four Ficus species present in a patch. This suggests that parasitoid fig wasps have relatively broad host- Ficus species ranges compared to fig wasps that oviposit internally. Parasitoid fig wasps did not recruit on all available host plants present in the forest census area and suggests an important ecological consequence in mitigating fitness trade-offs between pollinator and Ficus reproduction. The extent to which parasitoid fig wasps exert influence on the pollination mutualism must consider the fitness consequences imposed by the ability to interact with phenotypes of multiple Ficus and fig wasps species, but not equally across space and time