368 research outputs found
The surgical point of view of the geriatric patient — Urinary incontinence
Summary: Background: Urinary incontinence is one of the most frequent diseases in the ageing population. The aim of this manuscript is to present the current knowledge on urinary incontinence regarding (i) prevalence, (ii) pathogenesis, (iii) types, (iv) diagnostic assessment, and (v) treatment options. Methods: The current literature regarding urinary incontinence with special reference to the geriatric patient was reviewed. Results: According to a study performed recently in the Vienna area, 36.0% of women and 11.5% of men aged 70 years or older report urinary incontinence. Several factors, such as urodynamic changes, structural alterations of the lower urinary tract, increased sensory input, and impaired central control of the micturition reflex, contribute to the high prevalence of urinary incontinence with age. The four most common forms of urinary incontinence in the geriatric patient are combined stress/urge incontinence, pure urge incontinence, pure stress incontinence, and overflow incontinence. Diagnostic steps are classified into "mandatory”, "recommended”, and "indicated in selected cases only”. Particularly the "mandatory tests” are simple to perform and need no special equipment. Therapeutic options should be directed to the type of urinary incontinence as well as the physical and mental status of the patient. Conclusions: Urinary incontinence is highly prevalent with age. Conservative treatment is the therapy of choice for urge incontinence and mild to moderate forms of stress and overflow incontinence in the geriatric patien
SU(2) symmetry in a Hubbard model with spin-orbit coupling
We study the underlying symmetry in a spin-orbit coupled tight-binding model
with Hubbard interaction. It is shown that, in the absence of the on-site
interaction, the system possesses the SU(2) symmetry arising from the
timereversal symmetry. The influence of the on-site interaction on the symmetry
depends on the topology of the networks: The SU(2) symmetry is shown to be the
spin rotation symmetry of a simply-connected lattice, so it still holds in the
presence of the Hubbard correlation. In contrary, the on-site interaction
breaks the SU(2) symmetry of a multi-connected lattice.Comment: 5 pages, 2 figure
Large-area synthesis of ferromagnetic FeGeTe/graphene van der Waals heterostructures with Curie temperature above room temperature
Van der Waals (vdW) heterostructures combining layered ferromagnets and other
two-dimensional (2D) crystals are promising building blocks for the realization
of ultra-compact devices with integrated magnetic, electronic and optical
functionalities. Their implementation in various technologies depends strongly
on the development of a bottom-up scalable synthesis approach allowing to
realize highly uniform heterostructures with well-defined interfaces between
different 2D layered materials. It also requires that each material component
of the heterostructure remains functional, which ideally includes ferromagnetic
order above room temperature for 2D ferromagnets. Here, we demonstrate
large-area growth of FeGeTe/graphene heterostructures achieved by
vdW epitaxy of FeGeTe on epitaxial graphene. Structural
characterization confirmed the realization of a continuous vdW heterostructure
film with a sharp interface between FeGeTe and graphene. Magnetic
and transport studies revealed that the ferromagnetic order persists well above
300 K with a perpendicular magnetic anisotropy. In addition, epitaxial graphene
on SiC(0001) continues to exhibit a high electronic quality. These results
represent an important advance beyond non-scalable flake exfoliation and
stacking methods, thus marking a crucial step toward the implementation of
ferromagnetic 2D materials in practical applications
Multilayers of InGaAs Nanostructures Grown on GaAs(210) Substrates
Multilayers of InGaAs nanostructures are grown on GaAs(210) by molecular beam epitaxy. With reducing the thickness of GaAs interlayer spacer, a transition from InGaAs quantum dashes to arrow-like nanostructures is observed by atomic force microscopy. Photoluminescence measurements reveal all the samples of different spacers with good optical properties. By adjusting the InGaAs coverage, both one-dimensional and two-dimensional lateral ordering of InGaAs/GaAs(210) nanostructures are achieved
The effect of strain and spatial Bi distribution on the band alignment of GaAsBi single quantum well structure
The band line-up and band offset calculations of GaAs0.978Bi0.022/GaAs single quantum well with spatial changes of Bi composition were reported. The spatial Bi profile and a certain amount of the Bi composition in the barrier layer were determined by HR-XRD measurements. Virtual Crystal Approximation and Valence Band Anti-Crossing models were used including strain effects to obtain conduction and valence band edge shifts with Bi incorporation. Photoluminescence (PL) measurements were performed at a low temperature of 8 K as a function of excitation intensity. The PL spectra have shown asymmetric line shapes, which were fitted with different Gaussian functions. Comparing experimental PL results with calculated band edge energies, it was found that optical transition is a type I under low intensity excitation while the optical transition is switched from type I to type II due to the spatial changes in Bi concentrations. The band offsets?Ec/?Ev were also determined
Self-organization of quantum-dot pairs by high-temperature droplet epitaxy
The spontaneously formation of epitaxial GaAs quantum-dot pairs was demonstrated on an AlGaAs surface using Ga droplets as a Ga nano-source. The dot pair formation was attributed to the anisotropy of surface diffusion during high-temperature droplet epitaxy
Fabrication of Nickel Nanostructure Arrays Via a Modified Nanosphere Lithography
In this paper, we present a modified nanosphere lithographic scheme that is based on the self-assembly and electroforming techniques. The scheme was demonstrated to fabricate a nickel template of ordered nanobowl arrays together with a nickel nanostructure array-patterned glass substrate. The hemispherical nanobowls exhibit uniform sizes and smooth interior surfaces, and the shallow nanobowls with a flat bottom on the glass substrate are interconnected as a net structure with uniform thickness. A multiphysics model based on the level set method (LSM) was built up to understand this fabricating process by tracking the interface between the growing nickel and the electrolyte. The fabricated nickel nanobowl template can be used as a mold of long lifetime in soft lithography due to the high strength of nickel. The nanostructure–patterned glass substrate can be used in optical and magnetic devices due to their shape effects. This fabrication scheme can also be extended to a wide range of metals and alloys
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