Laser modulated optical reflectance of thin semiconductor films on glass

Semiconductor films, deposited by reactive magnetron sputtering on glass substrates have been analyzed with the help of laser-modulated optical reflectance. The results are discussed with respect to the thermal and charge carrier transport properties. Semiconductor properties have been identified both for micro-crystalline and amorphous film

Enteroaggregative Escherichia coli: a public health hazard in Yaoundé, Cameroon?

The prevalence of various pathotypes of Escherichia coli was investigated during a case-control study conducted in children diarrhoea in Yaoundé. Isolates obtained from the stools samples of children aged 6 months to 5 years were selected on phenotypic basis, and identified by virulence genes detection using polymerase chain reactions. The most prevalent pathotype was enteroaggregative Escherichia coli (25.8%). Enteropathogenic Escherichia coli (3.6%), enterotoxigenic Escherichia coli (1%), and enteroinvasive Escherichia coli (0.2%) followed. No shiga toxin-producing Escherichia coli were identified. Enteroaggregative Escherichia coli was not associated with diarrhoea (cases 26.1%, controls 25.5%; P=0,887), unlike enteropathogenic Escherichia coli (cases 6.7%, controls 1%; P=0.003). Investigations into documented potentials of enteroaggregative Escherichia coli in causing diarrhoea and other related pathologies indicated that it could be a major public health threat in Cameroon despite the fact that it was not found associated with clinical diarrhoeal cases in this study. Keywords: Cameroon, diarrhoeagenic Escherichia coli, public health. Int. J. Biol. Chem. Sci. Vol. 2 (3) 2008: pp. 272-28

Study of optical properties of Zn1−x_{\rm 1-x}Bex_{\rm x}Te mixed crystals by means of combined modulated IR radiometry and photoacoustics

Photothermal experiments using photoacoustic, IR radiometric and piezoelectric detection have been conducted on semiconductors and on metal samples as reference. For the metal samples the IR emissivity has been determined for differently treated surfaces by comparing the photoacoustic and the IR radiometry response. For semiconductor mixed crystals consisting of Zn$_{\rm 1-x}$Be$_{\rm x}$Te information on the composition dependence and depth variation of the IR optical properties has been deduced from combined measurements based on modulated IR radiometry and photoacoustics performed as a function of modulation frequency at one selected excitation wavelength. For the semiconductor mixed crystals, additionally, the optical absorption in the spectral range 350 nm to 900 nm has been determined

TRAPPC11 and GOSR2 mutations associate with hypoglycosylation of α-dystroglycan and muscular dystrophy

Abstract Background Transport protein particle (TRAPP) is a supramolecular protein complex that functions in localizing proteins to the Golgi compartment. The TRAPPC11 subunit has been implicated in muscle disease by virtue of homozygous and compound heterozygous deleterious mutations being identified in individuals with limb girdle muscular dystrophy and congenital muscular dystrophy. It remains unclear how this protein leads to muscle disease. Furthermore, a role for this protein, or any other membrane trafficking protein, in the etiology of the dystroglycanopathy group of muscular dystrophies has yet to be found. Here, using a multidisciplinary approach including genetics, immunofluorescence, western blotting, and live cell analysis, we implicate both TRAPPC11 and another membrane trafficking protein, GOSR2, in α-dystroglycan hypoglycosylation. Case presentation Subject 1 presented with severe epileptic episodes and subsequent developmental deterioration. Upon clinical evaluation she was found to have brain, eye, and liver abnormalities. Her serum aminotransferases and creatine kinase were abnormally high. Subjects 2 and 3 are siblings from a family unrelated to subject 1. Both siblings displayed hypotonia, muscle weakness, low muscle bulk, and elevated creatine kinase levels. Subject 3 also developed a seizure disorder. Muscle biopsies from subjects 1 and 3 were severely dystrophic with abnormal immunofluorescence and western blotting indicative of α-dystroglycan hypoglycosylation. Compound heterozygous mutations in TRAPPC11 were identified in subject 1: c.851A>C and c.965+5G>T. Cellular biological analyses on fibroblasts confirmed abnormal membrane trafficking. Subject 3 was found to have compound heterozygous mutations in GOSR2: c.430G>T and c.2T>G. Cellular biological analyses on fibroblasts from subject 3 using two different model cargo proteins did not reveal defects in protein transport. No mutations were found in any of the genes currently known to cause dystroglycanopathy in either individual. Conclusion Recessive mutations in TRAPPC11 and GOSR2 are associated with congenital muscular dystrophy and hypoglycosylation of α-dystroglycan. This is the first report linking membrane trafficking proteins to dystroglycanopathy and suggests that these genes should be considered in the diagnostic evaluation of patients with congenital muscular dystrophy and dystroglycanopathy