Bethe ansatz for the SU(4) extension of the Hubbard Model

We apply the nested algebraic Bethe ansatz method to solve the eigenvalue problem for the SU(4) extension of the Hubbard model. The Hamiltonian is equivalent to the SU(4) graded permutation operator. The graded Yang-Baxter equation and the graded Quantum Inverse Scattering Method are used to obtain the eigenvalue of the SU(4) extension of the Hubbard model.Comment: Latex file, 12 page

Impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field

We report on the observation and experimental studies of impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field. The terahertz electroluminescence is observed in a wide range of doping levels (at noncompensated donor density from 4.5×10[sup 16] to 3.4×10[sup 18] cm[sup −3]). Spectra of terahertz luminescence and photoconductivity are studied by means of Fourier transform spectrometry. Distinctive features of the spectra can be assigned to intracenter electron transitions between excited and ground states of silicon and oxygen donors and to hot electron transitions to the donor states.Peer reviewe

Double blind, randomized, placebo controlled clinical trial for the treatment of diabetic foot ulcers, using a nitric oxide releasing patch: PATHON

<p>Abstract</p> <p>Background</p> <p>Diabetes Mellitus constitutes one of the most important public health problems due to its high prevalence and enormous social and economic consequences. Diabetic foot ulcers are one of the chronic complications of diabetes mellitus and constitute the most important cause of non-traumatic amputation of inferior limbs. It is estimated that 15% of the diabetic population will develop an ulcer sometime in their lives. Although novel therapies have been proposed, there is no effective treatment for this pathology. Naturally produced nitric oxide participates in the wound healing process by stimulating the synthesis of collagen, triggering the release of chemotactic cytokines, increasing blood vessels permeability, promoting angiogenic activity, stimulating the release of epidermical growth factors, and by interfering with the bacterial mitochondrial respiratory chain. Topically administered nitric oxide has demonstrated to be effective and safe for the treatment of chronic ulcers secondary to cutaneous leishmaniasis. However, due to their unstable nitric oxide release, the topical donors needed to be applied frequently, diminishing the adherence to the treatment. This difficulty has led to the development of a multilayer polymeric transdermal patch produced by electrospinning technique that guarantees a constant nitric oxide release. The main objective of this study is to evaluate the effectiveness and safety of this novel nitric oxide releasing wound dressing for the treatment of diabetic foot ulcers.</p> <p>Methods and design</p> <p>A double-blind, placebo-controlled clinical trial, including 100 diabetic patients was designed. At the time of enrollment, a complete medical evaluation and laboratory tests will be performed, and those patients who meet the inclusion criteria randomly assigned to one of two groups. Over the course of 90 days group 1 will receive active patches and group 2 placebo patches. The patients will be seen by the research group at least every two weeks until the healing of the ulcer or the end of the treatment. During each visit the healing process of the ulcer, the patient's health status and the presence of adverse events will be assessed. Should the effectiveness of the patches be demonstrated an alternative treatment would then be available to patients.</p> <p>Trial registration</p> <p>NCT00428727.</p

Depth-dependent phase change in Gd2O3 epitaxial layers under ion irradiation

International audienceEpitaxial Gd2O3 thin layers with the cubic structure were irradiated with 4-MeV Au 2+ ions in the 10 13-10 15 cm-2 fluence range. X-ray diffraction indicates that ion irradiation induces a cubic to monoclinic phase change. Strikingly, although the energy-deposition profile of the Au 2+ ions is constant over the layer thickness, this phase transformation is depth-dependent, as revealed by a combined X-ray diffraction and ion channeling analysis. In fact, the transition initiates very close to the surface and propagates inwards, which can be explained by an assisted migration process of irradiation-induced defects. This result is promising for developing a method to control the thickness of the rare-earth oxide crystalline phases

Sustained silver-releasing dressing in the treatment of diabetic foot ulcers

This study investigated the clinical performance and safety of a sustained silver-releasing foam dressing, Contreet Foam, in the treatment of diabetic foot ulcers. Twenty-seven patients with diabetic foot ulcers of grade I or II (Wagner's classification) were followed for six weeks: one week run-in using Biatain dressings, four weeks' treatment with Contreet dressings. Four ulcers healed during the four-week treatment with Contreet 56% in average. Contreet Foam showed good exudate management properties and was considered easy to use. Only two infections occurred showed that all six of the non-study ulcers developed an infection during the study. All ulcers (study ulcers as well as non-study ulcers) were treated according to good practice of diabetic wound care. There were no directions for the treatment of secondary wounds. No device-related adverse events were observed. This study demonstrated that Contreet Foam is safe and easy to use and effectively supports healing and good wound progress of diabetic foot ulcers

Sustained silver-releasing dressing in the treatment of diabetic foot ulcers

This study investigated the clinical performance and safety of a sustained silver-releasing foam dressing, Contreet Foam, in the treatment of diabetic foot ulcers. Twenty-seven patients with diabetic foot ulcers of grade I or II (Wagner's classification) were followed for six weeks: one week run-in using Biatain dressings, four weeks' treatment with Contreet dressings. Four ulcers healed during the four-week treatment with Contreet 56% in average. Contreet Foam showed good exudate management properties and was considered easy to use. Only two infections occurred showed that all six of the non-study ulcers developed an infection during the study. All ulcers (study ulcers as well as non-study ulcers) were treated according to good practice of diabetic wound care. There were no directions for the treatment of secondary wounds. No device-related adverse events were observed. This study demonstrated that Contreet Foam is safe and easy to use and effectively supports healing and good wound progress of diabetic foot ulcers