Construction of a new selective coated disk electrode for Ag (I) based on modified polypyrrole-carbon nanotubes composite with new lariat ether.

A poly (vinyl chloride) (PVC) matrix membrane ion-selective electrode for silver (I) ion is fabricated based on modified polypyrrole - multiwalled carbon nanotubes composite with new lariat ether. This sensor has a Nernstian slope of 59.4±0.5mV/decade over a wide linear concentration range of 1.0×10(-7) to 1.0×10(-1)molL(-1) for silver (I) ion. It has a short response time of about 8.0s and can be used for at least 50days. The detection limit is 9.3×10(-8)molL(-1) for silver (I) ion, and the electrode was applicable in the wide pH range of 1.6 -7.7. The electrode shows good selectivity for silver ion against many cations such as Hg (II), which usually imposes serious interference in the determination of silver ion concentration. The use of multiwalled carbon nanotubes (MWCNTs) in a polymer matrix improves the linear range and sensitivity of the electrode. In addition by coating the solid contact with a layer of the polypyrrole (Ppy) before coating the membrane on it, not only did it reduce the drift in potential, but a shorter response time was also resulted. The proposed electrode was used as an indicator electrode for potentiometric titration of silver ions with chloride anions and in the titration of mixed halides. This electrode was successfully applied for the determination of silver ions in silver sulphadiazine as a burning cream.

LSN MS guidelines for the management of multiple sclerosis.

OBJECTIVE: The prevalence of multiple sclerosis (MS) in Lebanon is unknown, as there are no available or reliable epidemiological studies to date. The circumstances of Middle East countries are different from those of Europe and North America in terms of differential diagnoses and disease management. The aim of the conference is to establish guidelines for diagnosis, treatment, follow-up and management of patients with MS in Lebanon. Another objective is to discuss and participate in research projects based on epidemiology, clinical trials and more fundamental aspects of the disease in the future. METHODS: Under the authority of the Lebanese Society of Neurology (LSN), a group of neurologists took the initiative to participate in this LSN MS committee with the purpose of establishing a consensus for the management of patients with MS, and under the supervision of a Coordinator (A.T.) designed by the LSN board. RESULTS: Diagnostic and therapeutic, follow-up and research recommendations were proposed with special emphasis on the specific needs and circumstances of Lebanon. The experts highlighted the importance of considering particular needs, the identification of patients at high risk of developing MS in order to maximize therapeutic opportunities, and cost-effective control of treatment efficacy, as well as global assessment of disability. CONCLUSIONS: The experts established guidelines concerning diagnosis, treatment, and follow-up of patients with MS in Lebanon. Furthermore, they recommended some clinical and fundamental research projects.

Carbon nanotube composite coated platinum electrode for detection of Ga(III).

This study demonstrates the application of composite multi-walled carbon nanotube (MWCNT) polyvinylchloride (MWNT-PVC) based on 7-(2-hydroxy-5-methoxybenzyl)-5,6,7,8,9,10-hexahydro-2H benzo [b][1,4,7,10,13] dioxa triaza cyclopentadecine-3,11(4H,12H)-dione ionophore for gallium sensor. The sensor shows a good Nernstian slope of 19.68 ± 0.40 mV/decade in a wide linear range concentration of 7.9 × 10(-7) to 3.2 × 10(-2)M of Ga(NO(3))(3). The detection limit of this electrode is 5.2 × 10(-7)M of Ga(NO(3))(3). This proposed sensor is applicable in a pH range of 2.7-5.0. It has a short response time of about 10s and has a good selectivity over nineteen various metal ions. The practical analytical utility of this electrode is demonstrated by measurement of Ga(III) in river water.

Clinical characteristics of multiple sclerosis in Lebanon.

The epidemiologic, clinical, radiological and laboratory characterization of multiple sclerosis (MS) is very well documented in Caucasian and Japanese populations, but very little is known about MS in the Arab world. Such knowledge is becoming of paramount importance, with the recent advances in therapies, MRI techniques and other diagnostic procedures. We report a cohort of Lebanese MS patients, including details of their clinical and laboratory characteristics. The medical records of 202 patients fulfilling the Mc Donald's diagnostic criteria, and followed in our tertiary care center were reviewed. This cohort is highly representative of the disease in Lebanon where the number of MS patients is estimated to be between 1200 and 1700. The peak age of onset of MS in our cohort was in the third decade with 62.4% of patients developing their first symptoms between 20 and 39 years. The female/male ratio was 1.8/1.0. A positive family history for MS was present in 5% of patients. The most frequent presenting symptoms were brainstem-cerebellar (46.2%) followed by sensory (42.5%), motor (33.9%) and visual (29.6%). Of the total number of patients, 85.1% had relapsing remitting MS at onset, and 7.9% primary progressive MS. Benign MS defined as EDSS<=2.0 after 10 years from onset was present in 20% of patients. The mean time from onset to secondary progressive MS was around 9 years. Visual, brainstem, and somatosensory evoked potentials were abnormal in 65.6%, 27.8%, and 50.7% of patients tested respectively. Cerebrospinal fluid showed pleocytosis in 32.6%, increased IgG synthesis in 45.2%, positive oligoclonal bands in 40%, and elevated protein in 34% of patients tested. Although some of the clinical characteristics of our MS population were different compared to western series, the natural history of the disease was similar.