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H Type (h + type)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Analysis of Flow Patterns in a Ventricular Assist Device: A Comparative Study of Particle Image Velocimetry and Computational Fluid Dynamics

ARTIFICIAL ORGANS, Issue 4 2009
Katsutoshi Sato
Abstract:, In order to develop a diaphragm-type ventricular assist device (VAD), we studied the flow field change following structural modifications. We devised a center flow-type pump by putting a small projection on the center of the housing and/or diaphragm to provide a center in the flow field, and examined the following four types of VADs: N type without a projection, D type with a projection on the diaphragm, H type with a projection on the housing, and DH type with projections on both the diaphragm and housing. Computational fluid dynamics (CFD) was used for flow simulation. Particle image velocimetry (PIV) was also used to verify the reliability of the CFD method and to determine how the flow field changes in the presence of a projection. The results of the PIV and CFD analyses were comparable. The placement of a projection on the housing was most effective in rectifying the flow field. [source]

The Role of Ion Pairs in the Second-Order NLO Response of 4-X-1-Methylpiridinium Salts,

CHEMPHYSCHEM, Issue 2 2010
Francesca Tessore Dr.
Abstract A series of 4-X-1-methylpyridinium cationic nonlinear optical (NLO) chromophores (X=(E)-CHCHC6H5; (E)-CHCHC6H4 -4,-C(CH3)3; (E)-CHCHC6H4 -4,-N(CH3)2; (E)-CHCHC6H4 -4,-N(C4H9)2; (E,E)-(CHCH)2C6H4 -4,-N(CH3)2) with various organic (CF3SO3,, p -CH3C6H4SO3,), inorganic (I,, ClO4,, SCN,, [Hg2I6]2,) and organometallic (cis -[Ir(CO)2I2],) counter anions are studied with the aim of investigating the role of ion pairing and of ionic dissociation or aggregation of ion pairs in controlling their second-order NLO response in anhydrous chloroform solution. The combined use of electronic absorption spectra, conductimetric measurements and pulsed field gradient spin echo (PGSE) NMR experiments show that the second-order NLO response, investigated by the electric-field-induced second harmonic generation (EFISH) technique, of the salts of the cationic NLO chromophores strongly depends upon the nature of the counter anion and concentration. The ion pairs are the major species at concentration around 10,3,M, and their dipole moments were determined. Generally, below 5×10,4,M, ion pairs start to dissociate into ions with parallel increase of the second-order NLO response, due to the increased concentration of purely cationic NLO chromophores with improved NLO response. At concentration higher than 10,3,M, some multipolar aggregates, probably of H type, are formed, with parallel slight decrease of the second-order NLO response. Ion pairing is dependent upon the nature of the counter anion and on the electronic structure of the cationic NLO chromophore. It is very strong for the thiocyanate anion in particular and, albeit to a lesser extent, for the sulfonated anions. The latter show increased tendency to self-aggregate. [source]

Metabolism of phenylpropionic acid in enteropathogenic Escherichia coli belonging to serogroup O111 and its application for diagnosis

FEMS MICROBIOLOGY LETTERS, Issue 1 2001
Kinue Irino
Abstract We evaluated a biochemical assay based on the ability to metabolise ,-phenylpropionic acid (PPA) as a diagnostic aid in the identification of typical enteropathogenic Escherichia coli (EPEC) strains. A total of 1061 E. coli strains of serogroups O55, O111, and O119 were initially characterised regarding their H types (serotypes) and the presence of EPEC DNA sequences, eae, EAF, and bfpA. In case of the serogroup O111 strains, 84.6% carried the typical EPEC markers, and the great majority of those (98.1%) were PPA-positive. In contrast, only 0.9% of the serogroups O55 and O119 strains carrying the typical EPEC markers (53.6% and 75.4%, respectively) were PPA-positive. We conclude that the PPA test is a useful method to detect typical EPEC strains only among strains of the O111 serogroup. [source]

Reliability of patterns of hippocampal sclerosis as predictors of postsurgical outcome

EPILEPSIA, Issue 9 2010
Maria Thom
Summary Purpose:, Around one-third of patients undergoing temporal lobe surgery for the treatment of intractable temporal lobe epilepsy with hippocampal sclerosis (HS) fail to become seizure-free. Identifying reliable predictors of poor surgical outcome would be helpful in management. Atypical patterns of HS may be associated with poorer outcomes. Our aim was to identify atypical HS cases from a large surgical series and to correlate pathology with clinical and outcome data. Methods:, Quantitative neuropathologic evaluation on 165 hippocampal surgical specimens and 21 control hippocampi was carried out on NeuN-stained sections. Neuronal densities (NDs) were measured in CA4, CA3, CA2, and CA1 subfields. The severity of granule cell dispersion (GCD) was assessed. Results:, Comparison with control ND values identified the following patterns based on the severity and distribution of neuronal loss: classical HS (CHS; n = 60) and total HS (THS; n = 39). Atypical patterns were present in 30% of cases, including end-folium sclerosis (EFS; n = 5), CA1 predominant pattern (CA1p; n = 9), and indeterminate HS (IHS, n = 35). No HS was noted in 17 cases. Poorest outcomes were noted for no-HS, and CA1p groups with 33,44% International League Against Epilepsy (ILAE) class I at up to 2 years follow-up compared to 69% for CHS (p < 0.05). GCD associated with HS type (p < 0.01), but not with outcome. Conclusions:, These findings support the identification and delineation of atypical patterns of HS using quantitative methods. Atypical patterns may represent distinct clinicopathologic subtypes and may have predictive value following epilepsy surgery. [source]