Raman spectroscopy and photoluminescence study of PN junction p-graphene/n-GaAs.

Single layer graphene (SLG) was synthesized via high-quality chemical vapor deposition (CVD) on high-quality copper and subsequently transferred onto SiO2 and on n-GaAs substrates with varying doping electron concentrations (n = 1016, 1017, 5 × 1017, 1018, and 5 × 1018 cm-3). The n-GaAs substrates were grown by molecular beam epitaxy. The optical properties of the SLG were investigated through photoluminescence (PL) and Raman spectroscopy measurements. Carrier concentration n or p and Fermi energy (EF) values in SLG were determined both before and after the transfer onto n-GaAs, and these findings were validated through PL studies. The Raman spectroscopy results indicated an increase in the transfer of electrons from n-GaAs to SLG as the doping electron density in n-GaAs increased. PL analysis revealed a significant change in the bandgap energy (Eg) of n-GaAs due to bandgap narrowing and the Burstein-Moss shift. Our data enable us to determine the energy band diagrams. Upon aligning the energy bands, an increase in transferred carrier density is accompanied by changes in Fermi energies and an increase in the potential barrier (∆U). The increase in ∆U is of significant interest to ensure that charges are directed more efficiently toward the cell's electrical contacts in the case of photovoltaic application. There, they can contribute significantly to the generated electric current, thereby enhancing the performance of a cell. Our results can provide insights into the interaction in graphene-based heterostructures and aid in selecting the best parameters for developing new advanced devices.

[Erasmus syndrome: case report]. / Syndrome d'Erasmus: à propos d'une observation.

Erasmus' syndrome involves the association of systemic scleroderma and exposure to silica particles with or without silicosis. The authors report the observation of a miner with a history of professional silicosis resulting in pulmonary fibrosis. Twenty-five years later, the patient consulted for dysphagia associated with inflammatory arthralgia, cutaneous sclerosis extended to the face and limbs, sclerodactyly and Raynaud's phenomenon. The diagnosis of scleroderma was confirmed and Erasmus' syndrome was retained.

[Primary amyloidosis of the spine presenting with acute paraplegia]. / Amylose primitive et étagée du rachis dorsolombaire compliquée d'une paraplégie.

Primary amylosis is rarely located in bone, exceptionally in the spine. The radiographic presentation is polymorphous. Magnetic resonance imaging is currently the best imaging technique. Spinal amyloidosis can exceptionally lead to cord compression requiring rapid surgical release.

[Renal involvement in ankylosing spondylitis: concerning 210 cases]. / Les manifestations rénales de la spondylarthrite ankylosante: à propos de 210 cas.

PURPOSE: To define the epidemiology, clinical, biological and histological features of renal diseases in ankylosing spondylitis, ginving special attention to unusual forms. METHODS: We retrospectively reviewed the medical record of 28 cases with renal involvement among 210 cases of ankylosing spondylitis seen over a 27 year period who met the Amor criteria. RESULTS: Twenty-eight of 210 patients (13,3%) presented one or more signs of renal involvement: macroscopic hematuria (4 patients), microscopic hematuria (8 patients), proteinuria (15 patients), nephrotic syndrome (6 patients), decreased renal function (13 patients). Secondary renal amyloidosis and nephrolithiasis (8 patients) were the most common cause of renal involvement in ankylosing spondylitis followed by IgA nephropathy (3 patients). CONCLUSION: The funding of renal abnormalities in 13,3% of our patients suggests that in this illness evidence of renal involvement should be actively investigated in ankylosing spondylitis.