Investigation of the hydrogenation of SiCl4

A laboratory scale pressure reactor was constructed to study the 3 SiCl + 2H2 + Si yields 4 SiHCl3 reaction at pressures up to 500 psig. Reaction kinetic measurements were carried out as a function of reactor pressure, reaction temperature and H2/SiCl4 feed ratio. Based on the reaction kinetic data, the hydroclorination of SiCl4 and m.g. silicon metal is found to be an efficient process to produce SiHCl3 in good conversions and in high yields. Copper is an effective catalyst. Results of the corrosion study show that conventional nickel chromium alloys are suitable material of construction for the hydrochlorination reactor. The hydrochlorination reaction is relatively insensitive to external process parameters such as silicon particle size distribution and the impurities in the m.g. silicon metal

Krein systems

In the present paper we extend results of M.G. Krein associated to the spectral problem for Krein systems to systems with matrix valued accelerants with a possible jump discontinuity at the origin. Explicit formulas for the accelerant are given in terms of the matrizant of the system in question. Recent developments in the theory of continuous analogs of the resultant operator play an essential role

MYASTHENIA GRAVIS IN IRANIAN CHILDREN

ObjectiveThis study was undertaken to evaluate the clinical spectrum of myasthenia gravis in children and determine factors that help the clinician in his/her diagnosis and management.Materials & MethodsA retrospective review was performed on all pediatric patients suffering from myasthenia gravis (M.G) admitted in the department of pediatric neurology of the Mofid Hospital of the Shaheed Beheshti University, between 1994 and 2002.ResultsOf the thirty-two children with M.G. enrolled in our study, seven were suffering from the congenital type while the remaining (25 cases) had the juvenile M.G. Initial symptoms of congenital M.G were ptosis (7/7), limitation of eye movement (2/7) and mild generalized weakness (6/7). Although the Tensilon test was positive in 85% of congenital M.G cases, no myasthenia crisis or spontaneous remission was observed in any of them. In children with juvenile M.G, the age of presentation was 1.2 to 12.5 years, mean age 5.7+4.2 years (15 girls and 10 boys). The most common presenting symptoms in juvenile group were ptosis in 96% and generalized weakness in 76%. Eight of them (32%) had had at least one myasthenia crisis. EMG was diagnostic in 83% and one case the tensilon test was positive in 84%. One patient had hyperthyroidism and had already been diagnosed with hypothyroidism; two of them were epileptics. Eight patients underwent thymectomy microscopically; in specimens examined, five (62%) showed thymic follicular hyperplasia while in remaining three results were normal. One patient (12.5%) recovered completely after thymectomy with no need for medication during the follow up. Four patients (50%) showed relative  improvement and in three cases (37%) improvement was negligible.ConclusionThe results showed a female to male ratio of 1.5/1 which was correlated to adult M.G. The most common presenting symptoms consisted of ophtalmoplegia, with bilateral ptosis being the most significant. Although this study revealed that thymectomy lacks any remarkable prognostic influence, all patients had thymectomy after two years of disease onset. Some reports have indicated positive results if surgery was performed within two years of onset of disease.Key words: Myasthenia gravis, Children, Thymectomy, Congenita

Effects of aging on identifying emotions conveyed by point-light walkers

M.G. was supported by EC FP7 HBP (grant 604102), PITN-GA-011-290011 (ABC) FP7-ICT-2013-10/ 611909 (KOROIBOT), and by GI 305/4-1 and KA 1258/15-1, and BMBF, FKZ: 01GQ1002A. K.S.P. was supported by a BBSRC New Investigator Grant. A.B.S. and P.J.B. were supported by an operating grant (528206) from the Canadian Institutes for Health Research. The authors also thank Donna Waxman for her valuable help in data collection for all experiments described here.Peer reviewedPostprin

Teachers' right to strike vis-a-vis learners' right to education - justice for one is an injustice for the other

Published ArticleThe teachers' salary strike, which occurs almost annually in South Africa, is so widespread that it seems to have gained public toleration if not complete acceptance. However, the strike may have a lasting and devastating impact on the teachers' as well as the learners' discipline, motivation and morale, with the learners being the hardest hit. The strike has a negative impact on the learning and teaching culture and on the learners' academic performance. Although the teachers' strike is about salaries and salary-related matters, all too often, debates about it shift from the strike to the tension between the teachers' right to strike and the learners' right to receive education. This study endeavours to fathom the truth about the two rights, to establish whether they can stand side by side without contradicting each other, and to study their implications