Damage detection based on modal damping change in bridges

Structural Health Monitoring has drawn more attention from bridge engineers since the tragic collapse of the I-35W Mississippi River Bridge. In health monitoring of bridges, visual inspection has been the principal technique, while the reliability of this subjective technique heavily depends on the skills and experiences of the inspector. Objective techniques for structural monitoring should be useful to assist the visual inspection. A possible objective technique that has been investigated worldwide is vibration-based health monitoring. This paper aims to discuss the feasibility of vibration-based health monitoring in bridges, focusing on the damage detection based on the identification of change in their modal damping, by reporting the results of three different studies. A possibility of the damping change based damage detection was first examined by using the measurement data acquired from load car running test in the truss bridge with the cracks in the diagonal member. The energy-based modal damping analysis was next carried out to authenticate the accuracy of experimentally identified modal damping ratios in the steel arch bridge. Furthermore, by paying attention to the fact that the corrosion of RC structures is invisible, the detection of the corrosion-induced damage in RC beams by modal damping identification was studied experimentally. The main conclusions derived in this study are as follow: 1) The damping ratio of diagonal member-coupled mode was definitely increased by coupling of damaged diagonal member, suggesting the possibility of structural member’s damage detection by identifying changes in modal damping ratio of steel truss bridges. 2) Possibility of finding equivalent loss factors of the steel arch bridge components using energy-based damping analysis was successfully presented, and the energy-based damping analysis can be a powerful tool for the damage detection of bridges. 3) The modal damping is very sensitive indictor against corrosion-induced damage in the RC beams, and the local corrosion level might be detectable by measuring the modal damping ratio of RC structures

Clinical and genetic characterization of adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia associated with CSF1R mutation

Background and purpose: The clinical characteristics of colony stimulating factor 1 receptor (CSF1R) related adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) have been only partially elucidated. Methods: Clinical data from CSF1R mutation carriers who had been seen at our institutions or reported elsewhere were collected and analysed using a specific investigation sheet to standardize the data. Results: In all, 122 cases from 90 families with CSF1R mutations were identified. The mean age of onset was 43 years (range 18–78 years), the mean age at death was 53 years (range 23–84 years) and the mean disease duration was 6.8 years (range 1–29 years). Women had a significantly younger age of onset than men (40 vs. 47 years, P = 0.0006, 95% confidence interval 3.158–11.177). There was an age‐dependent penetrance that was significantly different between the sexes (P = 0.0013). Motor dysfunctions were the most frequent initial symptom in women whose diseases began in their 20s. Thinning of the corpus callosum, abnormal signalling in pyramidal tracts, diffusion‐restricted lesions and calcifications in the white matter were characteristic imaging findings of ALSP. The calcifications were more frequently reported in our case series than in the literature (54% vs. 3%). Seventy‐nine per cent of the mutations were located in the distal part of the tyrosine kinase domain of CSF1R (102 cases). There were no apparent phenotype−genotype correlations. Conclusions: The characteristics of ALSP were clarified. The phenotype of ALSP caused by CSF1R mutations is affected by sex

Computed tomography measurements of different dimensions of maxillary and frontal sinuses

<p>Abstract</p> <p>Background</p> <p>We have previously proposed the use of Doppler ultrasound to non-invasively stage sinus infection, as we showed that acoustic streaming could be generated in nonpurulent sinus secretions and helped to distinguish it from mucopurulent sinus secretions. In order to continue this development of a clinically applicable Doppler equipment, we need to determine different dimensions of the paranasal sinuses, especially the thickness of the anterior wall of the maxillary sinus (at the canine fossa). To the best of our knowledge, this is the first report on the thickness of the canine fossa. This study aimed to (a) estimate different dimensions of the maxillary and frontal sinuses measured on computed tomography (CT) of the head, (b) define cut-off values for the normal upper and lower limits of the different measured structures, (c) determine differences in age, side and gender, (d) compare manually and automatically estimated maxillary sinuses volumes, and (e) present incidental findings in the paranasal sinuses among the study patients.</p> <p>Methods</p> <p>Dimensions of 120 maxillary and frontal sinuses from head CTs were measured independently by two radiologists.</p> <p>Results</p> <p>The mean value of the maxillary sinus volume was 15.7 ± 5.3 cm³and significantly larger in males than in females (P = 0.004). There was no statistically significant correlation between the volume of maxillary sinuses with age or side. The mean value of the bone thickness at the canine fossa was 1.1 ± 0.4 mm. The automatically estimated volume of the maxillary sinuses was 14-17% higher than the calculated volume. There was high interobserver agreement with regard to the different measurements performed in this study. Different types of incidental findings of the paranasal sinuses were found in 35% of the patients.</p> <p>Conclusion</p> <p>We presented different dimensions of the maxillary and frontal sinuses on CTs. We believe that our data are necessary for further development of a clinically applicable Doppler equipment for staging rhinosinusitis.</p

Neuroacanthocytosis associated with a defect of the 4.1R membrane protein

BACKGROUND: Neuroacanthocytosis (NA) denotes a heterogeneous group of diseases that are characterized by nervous system abnormalities in association with acanthocytosis in the patients' blood. The 4.1R protein of the erythrocyte membrane is critical for the membrane-associated cytoskeleton structure and in central neurons it regulates the stabilization of AMPA receptors on the neuronal surface at the postsynaptic density. We report clinical, biochemical, and genetic features in four patients from four unrelated families with NA in order to explain the cause of morphological abnormalities and the relationship with neurodegenerative processes. CASE PRESENTATION: All patients were characterised by atypical NA with a novel alteration of the erythrocyte membrane: a 4.1R protein deficiency. The 4.1R protein content was significantly lower in patients (3.40 ± 0.42) than in controls (4.41 ± 0.40, P < 0.0001), reflecting weakened interactions of the cytoskeleton with the membrane. In patients IV:1 (RM23), IV:3 (RM15), and IV:6 (RM16) the 4.1 deficiency seemed to affect the horizontal interactions of spectrin and an impairment of the dimer self-association into tetramers was detected. In patient IV:1 (RM16) the 4.1 deficiency seemed to affect the skeletal attachment to membrane and the protein band 3 was partially reduced. CONCLUSION: A decreased expression pattern of the 4.1R protein was observed in the erythrocytes from patients with atypical NA, which might reflect the expression pattern in the central nervous system, especially basal ganglia, and might lead to dysfunction of AMPA-mediated glutamate transmission

MKLN1 splicing defect in dogs with lethal acrodermatitis

Lethal acrodermatitis (LAD) is a genodermatosis with monogenic autosomal recessive inheritance in Bull Terriers and Miniature Bull Terriers. The LAD phenotype is characterized by poor growth, immune deficiency, and skin lesions, especially at the paws. Utilizing a combination of genome wide association study and haplotype analysis, we mapped the LAD locus to a critical interval of similar to 1.11 Mb on chromosome 14. Whole genome sequencing of an LAD affected dog revealed a splice region variant in the MKLN1 gene that was not present in 191 control genomes (chr14:5,731,405T>G or MKLN/:c.400+3A>C). This variant showed perfect association in a larger combined Bull Terrier/Miniature Bull Terrier cohort of 46 cases and 294 controls. The variant was absent from 462 genetically diverse control dogs of 62 other dog breeds. RT-PCR analysis of skin RNA from an affected and a control dog demonstrated skipping of exon 4 in the MKLN1 transcripts of the LAD affected dog, which leads to a shift in the MKLN1 reading frame. MKLN1 encodes the widely expressed intracellular protein muskelin 1, for which diverse functions in cell adhesion, morphology, spreading, and intracellular transport processes are discussed. While the pathogenesis of LAD remains unclear, our data facilitate genetic testing of Bull Terriers and Miniature Bull Terriers to prevent the unintentional production of LAD affected dogs. This study may provide a starting point to further clarify the elusive physiological role of muskelin 1 in vivo.Peer reviewe

Advantageous estimation formula of the least roundoff noise for the cascade fixed-point digital filters

Lorsqu'un filtre digital à point fixe est exécuté par cascade des sections de deuxième ordre sous contraintes de plage dynamique, le bruit d'arrondissage résultant causé par la longueur de mot finie dépend beacoup du pairage de zéro de pôle et de l'ordre des sections. Deux procédures principales d'optimisation pour la réduction du bruit d'arrondissage sont disponibles, à savoir la procédure de programmation dynamique et celle heuristique. La procédure heuristique est plus pratique que celle de programmation dynamique, car sa durée de calcul est nettement plus courte et une solution presque optimale peut s'obtenir. C'est un grand avantage pour la procédure heuristique de présenter un critère pouvant juger si la solution presque optimale est acceptable. Pour la première fois, nous avons introduit un tel critère sous forme d'une formule d'estimation. Cette formule presente une limite inférieure de variation la plus importante possible du bruit d'arrondissage de sortie, et l'estimation peut être obtenue à partir de cette formule à travers un simple calcul. Nous avons étudié dans ce document la différence entre l'estimation et la solution exacte pour tous genres de filtres avec calculs d'ordinateur. Les estimations peuvent être calculées immédiatement et sont proches des solutions exactes correspondantes avec des différences de moins de 1,5 dB. Nous sommes convaincus que cette formule est très avantagause pour n'importe quelle procédure heuristique ayant des difficultés à trouver la solution exacte

Absence of linkage between familial amyotrophic lateral sclerosis and copper chaperone for the superoxide dismutase gene locus in two Italian pedigrees

We investigated the segregation of the copper chaperone for the superoxide dismutase (CCS) gene in two Italian families with amyotrophic lateral sclerosis lacking the mutations in superoxide dismutase 1 gene. We analyzed a total of 56 individuals; six people were affected. Diagnoses were made using the El Escorial criteria. The results of our study provide no evidence of a linkage between markers flanking the CCS gene and familial amyotrophic lateral sclerosis (FALS) in these FALS kindreds