1,032 research outputs found
g-Factors and diamagnetic coefficients of electrons, holes and excitons in InAs/InP quantum dots
The electron, hole, and exciton g-factors and diamagnetic coefficients have
been calculated using envelope-function theory for cylindrical InAs/InP quantum
dots in the presence of a magnetic field parallel to the dot symmetry axis. A
clear connection is established between the electron g-factor and the amplitude
of the those valence-state envelope functions which possess non-zero orbital
momentum associated with the envelope function. The dependence of the exciton
diamagnetic coefficients on the quantum dot height is found to correlate with
the energy dependence of the effective mass. Calculated exciton g-factor and
diamagnetic coefficients, constructed from the values associated with the
electron and hole constituents of the exciton, match experimental data well,
however including the Coulomb interaction between the electron and hole states
improves the agreement. Remote-band contributions to the valence-band
electronic structure, included perturbatively, reduce the agreement between
theory and experiment.Comment: 12 pages, 7 figure
Leerboek voor de historische grammatica van het Nederlands - Deel 1: Gotische grammatica, inleiding, klankleer
Descriptive and Comparative Linguistic
Leerboek voor de historische grammatica van het Nederlands - Deel 2: Flexie woordvorming
Descriptive and Comparative Linguistic
Electroporation Therapy in Soft Tissue Sarcoma: A Potentially Effective Novel Treatment
Purpose. Examination of the potential of electroporation therapy (EPT) in a patient with metastatic soft tissue sarcoma. Patient. A 24-year-old male who underwent extensive resection and postoperative radiotherapy for a malignant peripheral nerve sheath tumor in the right infratemporal fossa with intracranial extension and invasion of the maxillary sinus and mandible had a recurrence in the scar of his craniotomy for which he was initially treated with doxorubicin. After discontinuation of doxorubicin he developed a metastatic mass at the same site for which he was treated with electroporation therapy. Method. The subcutaneous metastasis was infiltrated with bleomycin and electroporated. Results. Gradually the tumor became increasingly necrotic and demarcated from surrounding tissue. After 10 weeks no tumor was seen anymore. The wound healed secondarily. Discussion. Intralesional bleomycin followed by EPT is potentially effective, well tolerated, and easy to perform in well accessible soft tissue sarcoma sites
Radiosensitization by bromodeoxyuridine and hyperthermia: analysis of linear and quadratic parameters of radiation survival curves of two human tumor cell lines
Paradigmawisselingen en constanten: 200 jaar taalkundige diversiteit
Interne en externe geschiedenis van het Nederlands en zijn dialecte
Feasibility of assessment of skeletal muscle mass on a single cross-sectional image at the level of the fourth thoracic vertebra
Background Skeletal muscle mass (SMM) determined on computed tomography (CT) is emerging as a novel imaging biomarker. Cross-sectional area (CSA) of SMM at the level of the third lumbar vertebra (L3) on abdominal imaging is considered the clinical reference standard for measuring SMM. In certain patient groups, such as those with oncological or non-oncological lung disease like COVID-19, a chest CT may be available while an abdominal CT is not. The purpose of this study was to investigate whether determining SMM on a chest CT is a feasible alternative to abdominal CT. Research question What is the correlation between SMM measurements at the level of L3 and the level of the fourth thoracic vertebra (Th4)? Study design and methods In this study we retrospectively analyzed abdominal and thoracic series of whole-body CT-scans of trauma patients (N = 47) and head and neck cancer patients (N = 194). All abdominal muscles were delineated on a single axial slice at the level of L3. The erector spinae, levator scapulae, rhomboideus minor and major and pectoralis minor and major muscles were delineated on a single axial slice at the level of Th4. CSA of the muscles at Th4 and the L3 level were compared using linear regression, and a multivariate linear regression model was established. Results Muscle CSA at level Th4 strongly correlates with L3 muscle CSA (r = 0.791, p < 0.05). A multivariate model incorporating the patient characteristics arm positioning, age, sex, and weight achieved a stronger correlation (r = 0.856, p < 0.05). Interpretation: Skeletal muscle CSA measured at the level of Th4 is a feasible alternative to measurements at L3. This allows diagnosing low SMM using clinically available thoracic CT-scans. SMM measurements at the level of Th4 may become a prognostic or triage tool when faced with mechanical ventilator shortage
Qualification of piezo-electric actuators for the MADMAX booster system at cryogenic temperatures and high magnetic fields
We report on the qualification of a piezo-based linear stage for the
manipulation of positions of dielectric discs in the booster of the MADMAX
axion dark matter search experiment. A first demonstrator of the piezo drives,
specifically developed for MADMAX, was tested at room temperature as well as at
cryogenic temperatures down to 4.5 K and inside strong magnetic fields up to
5.3 T. These qualification measurements prove that the piezo-based linear stage
is suited for MADMAX and fulfills the requirements.Comment: 13 pages, 9 figures, 2 table
Physics of IED Blast Shock Tube Simulations for mTBI Research
Shock tube experiments and simulations are conducted with a spherical gelatin filled skullâbrain surrogate, in order to study the mechanisms leading to blast induced mild traumatic brain injury. A shock tube including sensor system is optimized to simulate realistic improvised explosive device blast profiles obtained from full scale field tests. The response of the skullâbrain surrogate is monitored using pressure and strain measurements. Fluidâstructure interaction is modeled using a combination of computational fluid dynamics (CFD) simulations for the air blast, and a finite element model for the structural response. The results help to understand the physics of wave propagation, from air blast into the skullâbrain. The presence of openings on the skull and its orientation does have a strong effect on the internal pressure. A parameter study reveals that when there is an opening in the skull, the skull gives little protection and the internal pressure is fairly independent on the skull stiffness; the gelatin shear stiffness has little effect on the internal pressure. Simulations show that the presence of pressure sensors in the gelatin hardly disturbs the pressure field
- âŠ