Magnetotransport properties depending on the nanostructure of Fe(3)O(4) nanowires.

We have studied the magnetic behaviour of Fe(3)O(4) nanowires (NWs) with two different diameter ranges, above 150 nm and below 60 nm, made by electrodeposition techniques into a polymeric template. The nanowires were characterized using various techniques, in particular Mössbauer and thermoelectrical power measurements. The stoichiometric distribution of Fe cations showed clearly the presence of the magnetite inverse spinel electronic structure. Structural analysis performed using high-resolution transmission electron microscopy revealed two kinds of nanowire morphologies depending on the size. For nanowires above 150 nm in diameter, a contiguous network of well-bound nanoparticles was obtained. Instead, with a diameter of 60 nm, a polycrystalline structure was observed. The largest nanowires presented a magnetoresistance (MR) greater than 10%, whereas the thinner nanowires had almost none.

Preparation of silver nanoparticles in solution from a silver salt by laser irradiation.

A new method is proposed for the fabrication of a well-defined size and shape distribution of silver nanoparticles in solution; the method employs direct laser irradiation of an aqueous solution containing a silver salt and a surfactant in the absence of reducing agents.

[Retinal vasculitis. Epidemiological, clinical and etiological features]. / Les vascularites rétiniennes: profils épidémiologiques, cliniques et étiologiques.

PURPOSE: To study the epidemiological and clinical features of noninfectious retinal vasculitis (NIRV). METHODS: We analyzed 128 consecutive patients with NIRV, collected over 15 years (1993-2007) in an ophthalmological reference university hospital in Tunis, Tunisia. Data were analyzed regarding associated systemic disease, ocular syndromes, anatomic features (type and topography of vessel and type of capillaropathy), age and sex. The results of the etiologic work-up were based on the Levy-Clarke and Perez classification. RESULTS: A total of 240 cases of NIRV (128 patients) were collected (mean age: 32; sex ratio: 2.6). It was bilateral in 93.7% of cases. The mean visual acuity (VA) was 20/50 (range: 20/800-20/20). NIRV was mainly venous (84.1%), diffuse (57%), with a mixed capillaropathy (40.2%). There were complications in 56.25% of the cases, mainly macular edema (48.1%), vascular occlusion (25.9%), optic atrophy (22.2%) and cataract (19.2%). NIRV was idiopathic in 15.6% of the cases, characterized by a predominance of young subjects (mean: 38 years old), males (sex ratio: 4), VA at 20/25, and edematous periphlebitis in 100% of cases. There were ocular disorders in 12.5% of the cases and systemic disease in 72% of the cases, with a predominance of Behçet disease (BD): 53.9% of all patients and 81% of systemic disease with predominant venous features. In 48.3% of cases, VA was less than 20/200, due to BD in 48% of the cases. CONCLUSION: In NIRV, the etiologic work-up is oriented on anatomic presentation, based on fluorescein retinal angiography, and requires an interdisciplinary approach. In young adults with retinal phlebitis, BD is suggested first.

Nanowires network for biomolecular detection using contactless impedance tomoscopy technique.

Here we present the detection of ultralow concentrations of biomolecules in a device made from a polycarbonate membrane containing a network of gold nanowires and using a "contactless" impedance tomoscopy technique. The sensor comprises a thin dielectric layer with two parallel band electrodes on the one side and a microchannel containing gold nanowires onto which the adsorption of antibodies occurs. Upon applying a high-frequency ac voltage between the two electrodes, the adsorption process occurring at the surface of the gold nanowires can be followed through contactless impedance measurements. The configuration allows the real-time detection of biomolecules with a bulk concentration in the picomolar range.

The effect of chemical and heat disinfection of the hemodialysis machines on the spread of hepatitis C virus infection: a prospective study.

Seventeen of our 42 regular hemodialysis (HD) patients (40.5%), and six of our 16 patients on continuous ambulatory peritoneal dialysis (CAPD) (37%) were found to be positive for hepatitis C virus (HCV) antibody in June, 1992. Since the virus was considered susceptible to eradication by the available disinfection methods of the HD machines, the most likely source of transmission was considered to be incomplete application of the universal infection control techniques. These recommendations were strictly applied, but no attempt was made towards designating specific machines for anti-HCV positive patients. Review of data revealed that seven of our 25 previously negative patients (28%) turned positive in the following 12 months. Risk factors such as blood transfusions were excluded in all these patients. A strict protocol of careful chemical disinfection using Citrosteril run at 85 degrees C for 35 minutes after each dialysis session was adopted. Over the following 18 months, six of the remaining 17 negative patients (35.2%) seroconverted. They all had received blood transfusions, 7 to 14 months before (mean 10.5 months). The blood had been screened and had tested negative for anti-HCV antibody. By contrast, none of our CAPD patients who were anti-HCV negative in June 1992, and remained on CAPD, turned positive. The HD machine disinfection techniques were thoroughly reviewed and found to be as prescribed In the absence of other sources of infection with HCV we conclude that the HD machines were the most likely source of transmission of HCV infection and therefore, it is important to assign specific HD machines for anti-HCV positive patients. We have now adopted such a system.

Prevalence of glomerular diseases: king khalid university hospital, saudi arabia.

To obtain a more recent and comprehensive insight into the prevalence of glomerular diseases in our patient population, medical records of 200 patients with biopsy proven glomerulonephritis (GN), between January 1994 and June 1999, at the King Khalid University Hospital, Riyadh, Saudi Arabia were analyzed. Primary glomerular disease was found to be the most prevalent, accounting for 63.5% of all glomerular diseases. Among primary glomerular diseases, focal and segmental glomerulosclerosis (FSGS) was the most common histological lesion (34.6%) and was associated with a high prevalence of hypertension (86.4%), nephrotic syndrome (68.18%), hematuria (63.6%) and renal functional impairment (27.3%). Mesangioproliferative GN was the second most common lesion (25.1%) followed by mesangiocapillary GN (15.7%), IgA nephropathy (10.2%), and minimal change disease (8.5%). Amongst secondary glomerular diseases, lupus nephritis was the most prevalent (24.5%). In conclusion, primary glomerular diseases constituted the commonest group encountered and the prevalence of FSGS was quite high with male sex and young adults predominating. FSGS was also associated with a high prevalence of end-stage renal disease. Further collaborative studies are necessary to explore the predisposing factors and associations of glomerular disease, especially FSGS.