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Concerning intensity profiles.

The kinematical derivation of intensity profiles is considered. It is shown that the shapes of the profiles depend not only on the shape of the crystal but also on the crystal system and axial ratios of the unit cell and on the angles between the direction of the diffracted beam and the cell axes. For all crystal shapes, the widths of the profiles are determined by the Lorentz factor and the mean thickness of the crystal in the direction of the diffracted beam. The similarity of the intensity distributions of cubiform and spherical crystals is discussed. It is shown that almost identical results are obtained for the kinematical intensity profiles of a plane parallel plate having a large crystal edge ratio bathed in the beam and the dynamical profiles of thin plane parallel plates with infinite lateral extension. Extinction-corrected profiles of the plane parallel plate are compared with the results of the dynamical theory. In the case of a spherical crystal, the primary-extinction correction factor, y(p), obtained with extinction-corrected profiles is compared with y(p) commonly used in structure analysis.

Journal Article↗

The influences of ambiguity phase aberration profiles on focusing quality in the very near field--part I: single range focusing on transmission.

Most phase aberration measurement algorithms have an ambiguity for constant and tilted phase aberration profiles. Based on the Fresnel (near field) approximation with single range focusing and the Fraunhofer (far field) approximation, constant and tilted phase aberration profiles change the position of the focal point only and do not influence the image focusing quality. Therefore, ambiguity phase aberration profiles are generally considered to be harmless and ignored in those algorithms and related theoretical analyses. However, Fresnel and Fraunhofer approximations may become invalid under many medical ultrasound imaging situations, e.g., when the imaging field is in the very near field (f-number approximately 1). In the very near field, although it is known that constant and tilted phase aberration profiles may degrade the focusing quality, it seems that there is a lack of quantitative analysis results in the literature about their influences, and this is the purpose of the current paper. In this paper, a quantitative analysis with a very near field approximation is performed for single range focusing on transmission, which is a commonly used transmission focusing method in medical ultrasound imaging. The tolerable levels of constant and tilted phase aberration profiles are derived as a function of the imaging system's f-number and wavelength. Because some phase aberration measurement algorithms may also have an ambiguity for quadratic phase aberration profiles, they are also included in the analysis. The theoretical results are compared with numerical and simulation results. These results have shown that the influences of tilted and quadratic phase-aberration profiles can be ignored only under certain conditions in the very near field.

Algorithms↗

Angular-profile tuning of guided waves in hollow cylinders using a circumferential phased array.

Angular-profile tuning of guided waves in hollow cylinders is implemented by using partial loading of the elements in a circumferentially placed phased array. Each partial loading element generates nonaxisymmetric guided waves in a pipe. In earlier work, numerical calculations and experiments have shown that, for nonaxisymmetric guided waves, circumferential distribution of particle displacements (i.e., the angular profile) changes with propagation distance, frequency, and mode. To change the angular profile at a certain distance, either frequency or mode has to be changed for a single partial loading element. This is not the case, however, for a circumferential phased array. The total angular profile of a circumferential array is the superposition of contributions from all elements. If given the knowledge of the angular profile for a single element, the total guided wave angular profile can be controlled and thus focused at any specific circumferential location by a circumferentially placed phased array with adjustable voltage level and phase inputs. This angular profile tuning technique can be used for implementing a circumferential scan with focused, guided wave beams, which leads to the detection of smaller defects as a result of stronger focused beams. Algorithms and specific nondestructive evaluation (NDE) applications for pipe inspection using this technique are discussed.

Algorithms↗

Characterization of serotypes and outer membrane protein profiles in enteroaggregative Escherichia coli strains.

Twenty-four Escherichia coli strains mainly isolated from children with diarrhea in São Paulo, and showing characteristics of enteroaggregative E. coli (EAEC), were characterized by serotyping and outer membrane protein (OMP) profiles. The relationship between these characteristics was evaluated, as well as the usefulness of OMP profiles in the clonal analysis of EAEC strains. All strains presented aggregative adherence to HeLa cells and were classified in two groups based on their interaction with the EAEC DNA probe. A diversity of serotypes and OMP profiles was observed in both groups studied. Although no significant correlation between serotypes and OMP profiles was observed, unique OMP profiles were identified in 80% of the probe-positive strains which were distributed in only 4 OMP profiles. This result may indicate the presence of a few clones in the probe-positive group. On the other hand, probe-negative strains seem to constitute a more diverse group. In general, the observed heterogeneity in serotypes and OMP profiles described in the present study suggest a great genetic diversity in EAEC isolates of either the same or different serotypes and in strains presenting the same EAEC markers identified in our community.

Bacterial Outer Membrane Proteins↗

Development of the combined assessment of residential environments (CARE) profiles.

AIM: This paper reports the development and initial testing of the combined assessment of residential environments (CARE) profiles, which identify the frequency of positive events over a specified time based on the perceptions of residents, relatives and staff in care home settings. BACKGROUND: Despite the well-known benefits of positive events for subjective well-being, little is known about the nature of positive events experienced by residents, relatives and staff in care homes. There is also a dearth of tools capable of systematically evaluating how frequently these events occur in this context. METHODS: The CARE profiles were developed and tested between February 2004 and June 2005 with a combined sample of 372 residents, relatives and staff drawn from 11 care homes. An Event Frequency Approach was adopted to create three questionnaires (residents, relatives and staff), each containing 30 consensually valid positive events. The thematic content of these events was balanced for each questionnaire using the Senses Framework as a theoretical model. Once completed, the CARE profiles were tested in four care homes. RESULTS: Test data from the CARE profiles were used to produce a bar chart showing median frequencies of positive events experienced by residents, relatives and staff during the timeframe in question (e.g. 1 month). These profiles were shown to be internally consistent, with alpha scores ranging from 0.70 to 0.89 for residents, 0.91 to 0.94 for relatives and 0.78 to 0.92 for staff. CONCLUSION: We envisage that feedback from the CARE profiles will both reinforce good care home practice and identify areas for change based on the experiences of all major stakeholders. However, further development of the profiles is needed if the experiences of cognitively impaired residents are to be included in the assessment process.

Adaptation, Psychological↗

The antioxidant profiles of patients with recurrent acute and chronic pancreatitis.

OBJECTIVE: It has been suggested that patients with chronic pancreatitis have antioxidant deficiencies. It is unclear whether these antioxidant deficiencies also occur in patients with recurrent acute pancreatitis and whether this condition represents an intermediate state between normality and chronic pancreatitis. The aim of this study was to determine the antioxidant profiles of patients with pancreatitis (recurrent acute and chronic) and to compare their profiles with a control population. METHODS: The antioxidant profiles of patients with chronic pancreatitis (n = 27) and recurrent acute pancreatitis (n = 11) were determined and compared with the antioxidant profiles of control subjects (n = 19). The following parameters were measured in blood: trace elements (selenium, copper, zinc), vitamins A and E, and carotenoids (alpha-carotene, beta-carotene, xanthine, beta-cryptoxanthine, lycopene). RESULTS: Patients with chronic pancreatitis had significantly lower plasma concentrations of selenium, vitamin A, vitamin E, beta-carotene, xanthine, beta-cryptoxanthine, and lycopene compared with both control subjects and patients with recurrent acute pancreatitis (p < 0.05). There were no significant differences between the antioxidant profiles of patients with chronic pancreatitis due to alcohol excess and patients with idiopathic chronic pancreatitis, or between the antioxidant profiles of patients with recurrent acute pancreatitis and control subjects. CONCLUSIONS: Patients with chronic pancreatitis had evidence of multiple antioxidant deficiencies. The antioxidant profiles of patients with recurrent acute pancreatitis did not differ from those of control subjects, discounting the hypothesis that recurrent acute pancreatitis represents an intermediate state between normality and chronic pancreatitis.

Acute Disease↗

Hydropathy profile alignment: a tool to search for structural homologues of membrane proteins.

Hydropathy profile alignment is introduced as a tool in functional genomics. The architecture of membrane proteins is reflected in the hydropathy profile of the amino acid sequence. Both secondary and tertiary structural elements determine the profile which provides enough sensitivity to detect evolutionary links between membrane proteins that are based on structural rather than sequence similarities. Since structure is better conserved than amino acid sequence, the hydropathy profile can detect more distant evolutionary relationships than can be detected by the primary structure. The technique is demonstrated by two approaches in the analysis of a subset of membrane proteins coded on the Escherichia coli and Bacillus subtilis genomes. The subset includes secondary transporters of the 12 helix type. In the first approach, the hydropathy profiles of proteins for which no function is known are aligned with the profiles of all other proteins in the subset to search for structural paralogues with known function. In the second approach, family hydropathy profiles of 8 defined families of secondary transporters that fall into 4 different structural classes (SC-ST1-4) are used to screen the membrane protein set for members of the structural classes. The analysis reveals that over 100 membrane proteins on each genome fall in only two structural classes. The largest structural class, SC-ST1, correlates largely with the Major Facilitator Superfamily defined before, but the number of families within the class has increased up to 57. The second large structural class, SC-ST2 contains secondary transporters for amino acids and amines and consists of 12 families.

Amino Acid Sequence↗

Dental welfare profiles in a group of disabled Norwegian adults.

In a group of 496 non-institutionalized disabled Norwegian adults the possibility of identifying groups with particular dental welfare profiles which could be ascribed to a set of resource profiles was studied. Eight independent resource variables and seven dependent dental welfare variables were included in the model using canonical correlation analysis. Three main dental welfare profiles were identified: The most important profile was dominated by number of own teeth and differences were mainly ascribed to age, income, marital status and education. The second profile comprised a combination of absence of payment arrangement, chewing problems and barriers for dental care and differences were ascribed to sex, hospital experience, and organized assistance. The third profile discriminating between the disabled individuals was problems with performing dental hygiene associated with irregular use of dental services and barriers for dental care and differences were related to sex, marital status, degree of dependency, and organized assistance. For all profiles, individual characteristics were more important than contextual resources.

Adult↗

Influence of enzyme induction and exposure profile on liver injury due to chlorinated hydrocarbon inhalation.

Rats were exposed for four weeks either to air or to vapours of chloroform, carbon tetrachloride or 1,1-dichloroethylene given either as a constant concentration (continuous profile) or as repeated exposures for 6 hr per day, 5 days per week (fluctuating profile). Vapour concentrations were used such that the total exposure (concentration x time) was the same for the two profiles. Within each group, some animals received the enzyme-inducing agents, phenobarbitone or 1,3-butanediol, in their drinking water. Separate experiments were conducted to determine the influence of enzyme inducers and vapour concentration on chlorocarbon uptake and metabolism. In the case of chloroform, hepatic injury was more severe in animals exposed to constant vapour concentration, while dichloroethylene was more toxic when given as a fluctuating profile, especially in butanediol-treated rats. Carbon tetrachloride hepatotoxicity was similar in the two exposure profiles but was exacerbated by butanediol treatment. Butanediol-treated animals in the fluctuating profile group showed evidence of developing cirrhosis. These results could not be fully explained on the basis of the effect of enzyme inducers and exposure profile on amount of agent metabolized. Both the amount of toxic metabolites and the temporal pattern of their formation appear to be important determinants of liver injury.

Administration, Inhalation↗

Prediction of the plasma concentration profiles of orally administered drugs in rats on the basis of gastrointestinal transit kinetics and absorbability.

A new method based on gastrointestinal transit kinetics has been developed for estimation of the absorption profiles of drugs administered orally as aqueous solutions. The utility of the method was evaluated in rats. The gastrointestinal transit profile for each segment was estimated by in-vivo studies using phenol red, an unabsorbable marker. The gastrointestinal transit profile of phenol red was well explained by a linear gastrointestinal transit kinetic model with eight segments. We also introduced the absorption process into the gastrointestinal transit kinetic model and the plasma profile was predicted by the convolution method. The absorbability of drugs in each segment was assessed by an in-situ absorption study. The validity of the model was evaluated for model drugs with different absorption characteristics. The plasma profiles predicted for ampicillin, theophylline and cephalexin were in good agreement with those observed. The overestimated plasma profile of propranolol suggests that the low bioavailability of propranolol is a result of first-pass metabolism by the intestine wall and the liver, because the calculated absolute absorption is almost perfect. This proposed model is also suitable for estimation of segmental absorption, which is useful for the development of drug delivery systems. We have demonstrated that the plasma profile of orally administered drugs can be predicted by use of gastrointestinal transit and segmental absorbability information and that this method is especially useful for estimating separately the effect of absolute absorption and first-pass metabolism on the bioavailability of drugs.

Administration, Oral↗

Ion chamber measurements of transverse gamma knife beam profiles.

A microchamber, PTW Pinpoint 31006, was used to measure transverse beam profiles for an Elekta Gamma Knife, Model B, and compared with profiles measured with film dosimetry. The microchamber sensitive volume has a diameter of 2 mm, which is smaller than the gamma knife beams, and a length of 5 mm. The chamber was mounted in a custom cassette in a spherical plastic phantom, supplied by Elekta, and oriented in a sagittal plane with the 2-mm dimension at right angles to the transverse plane. The phantom was manually moved across the beam, using the gamma knife x-coordinate trunnions, to measure the profiles. Profiles were also measured with V-film placed in a cassette mounted in the spherical plastic phantom. The films were scanned with a Scanditronix film scanner and converted to dose with a density to dose calibration curve. The results were superimposed for comparison. The beam width at the 50% intensity was measured from the film profiles to give the dimensions of the beams in the orthagonal planes. The ion chamber measurements are compared with the film results for the transverse, x profiles. Good agreement between the film and ion chamber transverse profiles is observed.

Calibration↗

Amiodarone analog-dependent effects on CYP2C9-mediated metabolism and kinetic profiles.

CYP2C9 substrates can exhibit both hyperbolic and atypical kinetic profiles, and their metabolism can be activated or inhibited depending on the effector studied. CYP2C9 genetic variants can also affect both substrate turnover and kinetic profile. The present study assessed whether analogs of the effector amiodarone differentially altered the atypical kinetic profile of the substrate naproxen and whether this effect was genotype-dependent. Amiodarone, desethylamiodarone, benzbromarone, and its dimethyl analog (benz(meth)arone) were incubated with naproxen and either CYP2C9.1 or CYP2C9.3. Amiodarone activated naproxen demethylation at lower concentrations, regardless of the CYP2C9 allele, and inhibited metabolism at higher concentrations without altering the kinetic profile. Desethylamiodarone was a potent inhibitor of naproxen demethylation, irrespective of the CYP2C9 allele. Benzbromarone altered naproxen demethylation kinetics from a biphasic profile to that of a hyperbolic form in CYP2C9.1 and CYP2C9.3, resulting in inhibition and activation, respectively. In contrast, benz(meth)arone activated naproxen demethylation in both CYP2C9.1 and CYP2C9.3. In addition, the kinetic profile of naproxen demethylation became more hyperbolic at lower concentrations of benz(meth)arone and then reverted back to biphasic as the benz(meth)arone was increased further. Equilibrium binding and multiple-ligand docking studies were used to propose how such similar compounds exerted very different effects on naproxen metabolism. In summary, effectors of CYP2C9 metabolism can alter not only the degree of substrate turnover (activation or inhibition) but also the kinetic profile of metabolism of CYP2C9 substrates through effects on substrate binding and orientation. In addition, these kinetics effects are concentration- and genotype-dependent.

Amiodarone↗

Middle-age alterations in the sexually dimorphic plasma growth hormone profiles: involvement of growth hormone-releasing factor and effects on cytochrome p450 expression.

Rat liver, as well as other species, contains numerous sex-dependent isoforms of cytochrome P450 (P450) that are regulated by the sexually dimorphic profiles of circulating growth hormone. During puberty, young adulthood, and senescence, changes in the hormonal profiles appear to be responsible for alterations in age-associated expression levels of selective P450 isoforms. In contrast, little is known about the growth hormone secretory profiles and their P450-dependent expression levels during middle age. In the present study, we observed subtle changes in the hormonal concentrations, and frequencies of peaks and interpulse periods in the sexually dimorphic growth hormone profiles of 1-year-old male and female rats correlated to suppression of male-specific isoforms CYP2C11 and CYP2C13 and female-predominant CYP2C7. To identify possible causes for the age-associated changes in the circulating growth hormone profiles, the responsiveness of the hypothalamic-pituitary axis to growth hormone secretagogues clonidine and growth hormone-releasing factor (GRF) were examined in middle-aged male and female rats. In spite of the same sexually dimorphic response in young adult and middle-aged rats to both secretogogues (males > females), the pituitary somatotrophs in the older animals exhibited a dramatic decrease in sensitivity to clonidine, characterized by subnormal growth hormone release levels and an inordinate delay in pituitary response to clonidine stimulation. Results from similar studies conducted on middle-aged arcuate nucleus-lesioned rats suggest that a decline in GRF secretion is a possible contributor to the age-associated alterations in plasma growth hormone profiles during middle age. These changes in GRF-induced, sexually dimorphic secretory growth hormone profiles and the accompanying decline in P450 expression levels may anticipate similar, but more profound, changes to occur during senescence.

Age Factors↗

Initial concentration-time profile of gentamicin determines efficacy against Enterobacter cloacae ATCC 13047.

In vitro studies were designed to investigate the influence of peak drug concentration (Cmax), the area under the concentration-time curve (AUC), and, consequently, the trough concentration on the bactericidal effects of gentamicin against Enterobacter cloacae (MIC, 0.5 mg/liter) by simulating bolus versus infusion administration and bolus dosing with altered drug clearance. Bacteria in the lag phase were exposed to gentamicin concentration-time profiles modelling either bolus or infusion dosing (AUC constant, Cmax changing) with 30-min postdose peak concentrations (Cpeak30) of 4, 6, 8, and 10 mg/liter or bolus dosing with normal and double drug clearance (Cmax constant, AUC changing) corresponding to normal clearance profiles with Cpeak30 of 6 and 8 mg/liter. Exposure to gentamicin caused early bactericidal effects apparent by 2 h, followed by variable bacteriostatic and recovery phases. Exposure to bolus profiles resulted in greater bactericidal activity than the corresponding infusion profile up to a Cpeak30 of 8 mg/liter. At a Cpeak30 of 10 mg/liter, there were no differences in bactericidal effect. Double clearance profiles had a reduced bactericidal effect at 6 mg/liter compared to the corresponding normal clearance profile, but no differences in bactericidal effect were observed for 8-mg/liter double and normal clearance profiles. These results suggest that the initial exposure (i.e., 0 to 30 min) is a more important determinant for bacterial killing than the AUC or trough concentration for this bacterium. Subject to confirmation of these findings with other gram-negative bacteria, to optimize aminoglycoside efficacy the initial exposure (Cmax) should be maximized by giving higher doses or bolus administration at intervals which may not produce detectable trough concentrations. Clinical trials with a broad range of patients, especially those with higher clearance, would confirm these in vitro observations and define optimal dosing recommendations.

Anti-Bacterial Agents↗

Accuracy, reproducibility, and interpretation of Fatty Acid methyl ester profiles of model bacterial communities.

We determined the accuracy and reproducibility of whole-community fatty acid methyl ester (FAME) analysis with two model bacterial communities differing in composition by using the Microbial ID, Inc. (MIDI), system. The biomass, taxonomic structure, and expected MIDI-FAME profiles under a variety of environmental conditions were known for these model communities a priori. Not all members of each community could be detected in the composite profile because of lack of fatty acid "signatures" in some isolates or because of variations (approximately fivefold) in fatty acid yield across taxa. MIDI-FAME profiles of replicate subsamples of a given community were similar in terms of fatty acid yield per unit of community dry weight and relative proportions of specific fatty acids. Principal-components analysis (PCA) of MIDI-FAME profiles resulted in a clear separation of the two different communities and a clustering of replicates of each community from two separate experiments on the first PCA axis. The first PCA axis accounted for 57.1% of the variance in the data and was correlated with fatty acids that varied significantly between communities and reflected the underlying community taxonomic structure. On the basis of our data, community fatty acid profiles can be used to assess the relative similarities and differences of microbial communities that differ in taxonomic composition. However, detailed interpretation of community fatty acid profiles in terms of biomass or community taxonomic composition must be viewed with caution until our knowledge of the quantitative and qualitative distribution of fatty acids over a wide variety of taxa and the effects of growth conditions on fatty acid profiles is more extensive.

Journal Article↗

Species differentiation of a diverse suite of Bacillus spores by mass spectrometry-based protein profiling.

In this study, we demonstrate the versatility of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOFMS) protein profiling for the species differentiation of a diverse suite of Bacillus spores. MALDI-TOFMS protein profiles of 11 different strains of Bacillus spores, encompassing nine different species, were evaluated. Bacillus species selected for MALDI-TOFMS analysis represented the spore-forming bacterial diversity of typical class 100K clean room spacecraft assembly facilities. A one-step sample treatment and MALDI-TOFMS preparation were used to minimize the sample preparation time. A library of MALDI-TOFMS spectra was created from these nine Bacillus species, the most diverse protein profiling study of the genus reported to date. Linear correlation analysis was used to successfully differentiate the MALDI-TOFMS protein profiles from all strains evaluated in this study. The MALDI-TOFMS protein profiles were compared with 16S rDNA sequences for their bacterial systematics and molecular phylogenetic affiliations. The MALDI-TOFMS profiles were found to be complementary to the 16S rDNA analysis. Proteomic studies of Bacillus subtilis 168 were pursued to identify proteins represented by the biomarker peaks in the MALDI-TOFMS spectrum. Four small, acid-soluble proteins (A, B, C, and D), one DNA binding protein, hypothetical protein ymf J, and four proteins associated with the spore coat and spore coat formation (coat JB, coat F, coat T, and spoIVA) were identified. The ability to visualize higher-molecular-mass coat proteins (10 to 25 kDa) as well as smaller proteins (<10 kDa) with MALDI-TOFMS profiling is critical for the complete and effective species differentiation of the Bacillus genus.

Bacillus↗

Two physically and serologically distinct lipopolysaccharide profiles in strains of Bordetella pertussis and their phenotype variants.

The lipopolysaccharide (LPS) from nine strains representing 18 phenotype variants of Bordetella pertussis could be grouped into one of two distinct profiles by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining. One group, representing the wild-type LPS profile of B. pertussis, consisted of two silver-staining bands: a dominant brown-amber a band and a faster-migrating, minor, black-staining b band. The second group, representing a variant LPS profile, consisted of a single black-staining band of similar mobility to the b band in the wild-type profile. By electrophoretic transfer (Western) blot analysis, mouse antiserum raised against whole cells of Tohama I (prototype wild-type LPS strain) recognized only the a band from all strains/phenotypes possessing the wild-type LPS profile. In contrast, mouse antiserum raised against whole cells of 134 (prototype variant LPS strain) recognized all b bands, regardless of strain/phenotype, and could be shown to cross-react weakly with the a band from Tohama I. These results and results from cohemagglutination and immunodiffusion analyses support the classification of B. pertussis into one of two physiologically and serologically distinct LPS phenotypes: Lps AB for the wild-type profile and Lps B for the variant profile. The relationship of LPS type and phenotypic, or "phase," variation is discussed.

Animals↗

Comparison of outer membrane protein and biochemical profiles of Haemophilus aegyptius and Haemophilus influenzae biotype III.

Haemophilus aegyptius and Haemophilus influenzae biotype III are morphologically and biochemically similar; however, their outer membrane protein (Sarkosyl insoluble) profiles are distinct. Of 18 strains of H. aegyptius examined, 15 had a type 1 protein profile, and 3 had a type 2 profile, whereas the 5 strains of H. influenzae biotype III examined had three other protein profile types. All Haemophilus strains examined had 31- and 76-kilodalton (kDa) proteins and minor proteins with molecular masses between 20 and 100 kDa. H. aegyptius, with a type 1 protein profile, had major outer membrane proteins with apparent molecular masses of 27, 35.5, and 41.5 kDa, and H. aegyptius, with a type 2 protein profile, had 26-, 29-, 39.5-, and 41-kDa proteins. The type strain of H. influenzae biotype III had three major outer membrane proteins with apparent molecular masses of 29, 38.5 and 40 kDa. Four other strains designated as H. influenzae biotype III had major outer membrane proteins between 27 and 41.5 kDa representing two additional protein profiles.

Bacterial Outer Membrane Proteins↗