Intra-speaker and inter-speaker variability in speech sound pressure level across repeated readings

The intra- and inter-speaker variability of speech sound pressure level (SPL) has been investigated under repeatability conditions in this work. In a semi-anechoic chamber, speech from 17 individuals was recorded with a sound level meter, a headworn microphone, and a vocal monitoring device. The subjects were asked to read twice and in sequence two phonetically balanced passages. The speech variability has been investigated for mean, equivalent, and mode SPL from each reading and device. The intra-speaker variability has been evaluated by means of the average among individual standard deviations in the four readings and it reached the maximum of 2 dB for mode SPL. For the inter-speaker variability, the experimental standard deviation of individual averaged SPL parameters among the four repeated measures has been calculated, obtaining the highest value of 5.3 dB for mode SPL. Changes in SPL variability have been evaluated with different logging intervals for each device. The influence of speech material has been investigated by the Wilcoxon test on paired lists of descriptive statistics for SPL distribution and equivalent SPL in the repeated readings. The data reported in this study may be considered as a preliminary reference for the investigation of changes in speech SPL over subjects

The Spectrum of NF1 Mutations in Korean Patients with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant disorders in humans. NF1 is caused by mutations in the NF1 gene which consists of 57 exons and encodes a GTPase activating protein (GAP), neurofibromin. To date, more than 640 different NF1 mutations have been identified and registered in the Human Gene Mutation Database (HGMD). In order to assess the NF1 mutational spectrum in Korean NF1 patients, we screened 23 unrelated Korean NF1 patients for mutations in the coding region and splice sites of the NF1 gene. We have identified 21 distinct NF1 mutations in 22 patients. The mutations included 10 single base substitutions (3 missense and 7 nonsense), 10 splice site mutations, and 1 single base deletion. Eight mutations have been previously identified and thirteen mutations were novel. The mutations are evenly distributed across exon 3 through intron 47 of the NF1 gene and no mutational hot spots were found. This analysis revealed a wide spectrum of NF1 mutations in Korean patients. A genotype-phenotype correlation analysis suggests that there is no clear relationship between specific NF1 mutations and clinical features of the disease

Influence of Waste Glass Powder Addition on the Microstructure and Mechanical Properties of Autoclaved Building Materials

Lime quartz samples in which ground quartz sand was gradually substituted with waste glass powder (GP) were obtained under hydrothermal conditions to determine the influence of GP addition on the microstructure (observed by SEM), phase composition (analyzed by XRD), and compressive strength of autoclaved building materials. An additional series containing analytical grade NaOH and no GP was formed to evaluate the effect of sodium ions on tobermorite formation and its impact on the mechanical properties of the samples. GP addition hindered the formation of tobermorite during autoclaving. Instead, a higher amount of an amorphous and semi-crystalline C–S–H phase formed, leading to the densification of the composite matrix. Nevertheless, tobermorite-like structures were found during both XRD and SEM analyses, proving that the presence of small amounts of Al3+ ions allowed, to an extent, for the stabilization of the phase despite the high sodium content. The compressive strength values indicate that the presence of alkali in the system and the resulting formation of additional portions of C–S–H have a beneficial influence on the mechanical properties of autoclaved composites. However, the effect fades with increasing glass powder content which, together with a slight expansion of the samples, suggests that at high sand substitution levels, an alkali–silica reaction takes place

Analysis of variable expressivity in neurofibromatosis 1

Neurofibromatosis 1 (NF1) exhibits extreme clinical variability. This variability greatly increases the burden for affected families. The relationship of genetic factors to variable expressivity in NF1 is poorly understood. To improve understanding of NF1,1 studied relationships between several disease features in individuals and among affected relatives. My studies used clinical information on 4731 NF1 patients from three independent databases: the National NF Foundation International Database, the NF Institute Database and a population-based registry of NF1 patients in north-west England. My initial studies found associations between several pairs of features in affected probands and between the occurrence of individual features in affected parents and children. This establishes that some patients are more likely than others to develop particular NF1 features. Furthermore, the results of my logistic regressive models are consistent with grouping 9 of the features into three sets of associated features: 1) cafeau- lait spots, intertriginous freckling and Lisch nodules; 2 ) cutaneous, subcutaneous and plexiform neurofibromas; and 3) macrocephaly, optic glioma and other neoplasms. Also, the occurrence of Unidentified Bright Objects on magnetic resonance imaging in young (<21 years) NF1 patients was associated with other expressed diagnostic features. Clinical features within a group may share pathogenic mechanisms that differ, at least in part, from those underlying features in other groups. I found no local associations between the presence of cutaneous neurofibromas, plexiform neurofibromas, and cafe-au-lait spots in each of ten divisions of the body surface in NF1 patients. However, the correlation among relatives in the number of body segments affected with one or more lesions was positive and significant for all three features. The developments of cutaneous neurofibromas, plexiform neurofibromas, and cafe-au-lait spots in NF1 patients are each spatialy independent but influenced by familial factors. Familial aggregation patterns of NF1 features among various classes of affected relatives were used to examine familial aggregation in greater detail. Using multivariate analyses, statistically significant associations among different classes of relatives were found for several features. Three distinct patterns were observed among the associations for familial features: 1) Lisch nodules and cafe-au-lait spots had greater associations between 1st degree relatives than between 2 n d degree relatives; 2) Subcutaneous neurofibromas, plexiform neurofibromas, cafe-au-lait spots, and intertriginous freckling had greater associations between sibs than between parents and children; and 3) Head circumference and stature had similar associations for all affected relatives. These familial patterns suggest that unlinked modifying genes, the normal NF1 allele, and the mutant NF1 allele may all be involved in the development of particular clinical features of NF1, but that the relative contributions vary for different features. The results presented in this thesis suggest that genetic factors are involved in phenotypic variability in NFL These findings also provide specific clues to pathogenesis of NF1 features that can be tested in molecular studies. The methods of biostatistical analysis developed as part of this thesis can be applied to the study of other complex disorders.Medicine, Faculty ofMedical Genetics, Department ofGraduat