833 research outputs found
Giant peno-scrotal lymphoedema: surgical considerations and management
Chronic lymphoedema can affect any parts of the body, including the scrotum and penis. Massive scrotal lymphoedema with gross genital deformation is called penoscrotal elephantiasis1. Penoscrotal elephantiasis can be a functionally and emotionally incapacitating dilemma to the patients. Usually patients suffer from pain, chronic irritation, repeated infections, ambulatory problems, sexual dysfunction and social dejection. Congenital (primary) lymphoedema is due to malformation of the lymphatic vessels and are rare conditions for example the congenital hereditary elephantiasis of the Meige type2. Acquired (secondary) genital lymphoedema can be caused by genital infection such as lymphogranuloma venereum (LGV), filarial infestation like Wuchereria bancrofti, recurrent inflammation, tumors, lymph node dissection, trauma and radiotherapy3. With severe penoscrotal lymphoedema, the mainstay of treatment involves surgical excision, followed by reconstruction using local flaps or skin grafts. We present 3 cases of giant penoscrotal elephantiasis treated by excision and reconstruction with anterior and posterior flaps as a successful treatment of this difficult problem
Surgical reconstruction of Northern Uganda war victims.
Background: Aid groups estimate that since 1086 when the war conflicts in Northern Uganda started, over 30,000 people have died in the insurgency and over 20,000 people have remained maimed. Arising from the conflict, innocent civilians have had their limbs, lips, eyes, ears, noses, breasts, fingers and toes cut off.Patients and Methods: Between 2004 and 2005, a total of 34 victims of the Northern Uganda war, underwent reconstructive surgery. Most of the patients were treated from the local hospitals of Lira, Gulu and Kitgum.Results: Between 2004 and 2006, the Plastic Surgery team of Mulago hospital rehabilitated 34 victims of the northern war. Of these 23 were females and 11 were males. Most of these people had suffered severe disfigurements which necessitated multiple staged reconstructive procedures on them. The majority of the reconstructive operations were on the lips despite the fact that many victims had also suffered from mutilation of other body parts.Conclusion: Effects of the insurgency on individuals, families and communities included: Increased burden on health care delivery Hospital capacity overwhelmed with few doctors and nurses available Increased number of traumatised people Increased number of war causalities Population maimed with body parts cut off Increased dependency of local population on hand outs from government and relief agencies.Hence the need to strive for peaceful resolution of the Northern Uganda war conflict
Observation of light dragging in rubidium vapor cell
We report on the experimental demonstration of light dragging effect due to
atomic motion in a rubidium vapor cell. We found that the minimum group
velocity is achieved for light red-shifted from the center of the atomic
resonance, and that the value of this shift increases with decreasing group
velocity, in agreement with the theoretical predictions by Kocharovskaya,
Rostovtsev, and Scully [Phys. Rev. Lett. {\bf 86}, 628 (2001)].Comment: 4 pages 4 figures, submitted to PR
Congenital pseudarthrosis of the tibia - treatment with free valcusarised fibular grafts
Congenital pseudarthrosis is uncommon. We report on a series of 4 patients treated by means of free vascularised fibular grafts. Complications encountered were graft fracture, delayed union and angulation deformities. Modifications in the surgical technique i=proved later results. We recommend wide excision of pathological bone, bridging of the defect by free vascularised fibular grafts and rigid fixation
Congenital pseudarthrosis of the tibia : treatment with free vascularised fibular grafts
CITATION: Smith, C. S. F., Zeeman, V. R. B. J. & Wade, W. J. 1993. Congenital pseudarthrosis of the tibia : treatment with free vascularised fibular grafts. South African Medical Journal, 83:750-752.The original publication is available at http://www.samj.org.zaCongenital pseudarthrosis is uncommon. We report on a series of 4 patients treated by means of free vascularised fibular grafts. Complications encountered were graft fracture, delayed union and angulation deformities. Modifications in the surgical technique improved later results. We recommend wide excision of pathological bone, bridging of the defect by free vascularised fibular grafts and rigid fixation.Publisher’s versio
Surface flux estimates derived from UAS-based mole fraction measurements by means of a nocturnal boundary layer budget approach
The carbon exchange between ecosystems and the atmosphere has a large influence on the Earth system and specifically on the climate. This exchange is therefore being studied intensively, often using the eddy covariance (EC) technique. EC measurements provide reliable results under turbulent atmospheric conditions, but under stable conditions – as they often occur at night – these measurements are known to misrepresent exchange fluxes. Nocturnal boundary layer (NBL) budgets can provide independent flux estimates under stable conditions, but their application so far has been limited by rather high cost and practical difficulties. Unmanned aircraft systems (UASs) equipped with trace gas analysers have the potential to make this method more accessible. We present the methodology and results of a proof of concept study carried out during the ScaleX 2016 campaign. Successive vertical profiles of carbon dioxide dry air mole fraction in the NBL were taken with a compact analyser carried by a UAS. We estimate an average carbon dioxide flux of 12 μmol m−2 s−1, which is plausible for nocturnal respiration in this region in summer. Transport modelling suggests that the NBL budgets represent an area on the order of 100 km2
Exact solution of the Zeeman effect in single-electron systems
Contrary to popular belief, the Zeeman effect can be treated exactly in
single-electron systems, for arbitrary magnetic field strengths, as long as the
term quadratic in the magnetic field can be ignored. These formulas were
actually derived already around 1927 by Darwin, using the classical picture of
angular momentum, and presented in their proper quantum-mechanical form in 1933
by Bethe, although without any proof. The expressions have since been more or
less lost from the literature; instead, the conventional treatment nowadays is
to present only the approximations for weak and strong fields, respectively.
However, in fusion research and other plasma physics applications, the magnetic
fields applied to control the shape and position of the plasma span the entire
region from weak to strong fields, and there is a need for a unified treatment.
In this paper we present the detailed quantum-mechanical derivation of the
exact eigenenergies and eigenstates of hydrogen-like atoms and ions in a static
magnetic field. Notably, these formulas are not much more complicated than the
better-known approximations. Moreover, the derivation allows the value of the
electron spin gyromagnetic ratio to be different from 2. For
completeness, we then review the details of dipole transitions between two
hydrogenic levels, and calculate the corresponding Zeeman spectrum. The various
approximations made in the derivation are also discussed in details.Comment: 18 pages, 4 figures. Submitted to Physica Script
Proper time and Minkowski structure on causal graphs
For causal graphs we propose a definition of proper time which for small
scales is based on the concept of volume, while for large scales the usual
definition of length is applied. The scale where the change from "volume" to
"length" occurs is related to the size of a dynamical clock and defines a
natural cut-off for this type of clock. By changing the cut-off volume we may
probe the geometry of the causal graph on different scales and therey define a
continuum limit. This provides an alternative to the standard coarse graining
procedures. For regular causal lattice (like e.g. the 2-dim. light-cone
lattice) this concept can be proven to lead to a Minkowski structure. An
illustrative example of this approach is provided by the breather solutions of
the Sine-Gordon model on a 2-dimensional light-cone lattice.Comment: 15 pages, 4 figure
Quantized Rotation of Atoms From Photons with Orbital Angular Momentum
We demonstrate the coherent transfer of the orbital angular momentum of a
photon to an atom in quantized units of hbar, using a 2-photon stimulated Raman
process with Laguerre-Gaussian beams to generate an atomic vortex state in a
Bose-Einstein condensate of sodium atoms. We show that the process is coherent
by creating superpositions of different vortex states, where the relative phase
between the states is determined by the relative phases of the optical fields.
Furthermore, we create vortices of charge 2 by transferring to each atom the
orbital angular momentum of two photons.Comment: New version, 4 pages and 3 figures, accepted for publication in
Physical Review Letter
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