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At least 757 records · Page 42Linked to original sources
PubMed2006

Odor identification accuracy declines following 24 h of sleep deprivation.

Brain imaging studies demonstrate that sleep deprivation reduces glucose metabolism and blood flow in the prefrontal cortex, and such reductions are associated with impairments in cognitive functioning. Although some of the greatest metabolic declines occur within the orbitofrontal cortex, little is known about the effects of sleep loss on the types of processes mediated by this region, including emotion, motivation, feeding, and olfaction. The present study tested odor identification accuracy when individuals were well rested and again following 24 h of wakefulness. Relative to rested baseline performance, sleep-deprived individuals demonstrated a significant decline in the ability to identify specific odors on the Smell Identification Test. This decrement in olfactory functioning occurred concomitantly with slowed psychomotor speed and increased ratings of self-reported sleepiness. Performance on a task that required complex mental set shifting did not change significantly following sleep deprivation, suggesting that the decrements in odor identification could not be attributed to task difficulty. Finally, while there was no relationship between subjective sleepiness and odor identification at rested baseline, greater subjective sleepiness was associated with better odor identification ability following 24 h of sleep loss. Possible implications of these findings are discussed.

Adolescent↗
PubMedDate not supplied

Evaluation of two commercialized systems for the rapid identification of medically important yeasts.

A total of 77 recent clinical isolates of Candida albicans and other medically important yeasts were identified by two different commercial tests, Rapidec albicans (API-bioMérieux) and Fongiscreen 4H (Sanofi Diagnostics Pasteur), and conventional mycological methods. The strains were from 13 different species of yeasts and consisted of strains of 36 C. albicans, three of Candida famata, nine of Candida (Torulopsis) glabrata, five of Candida guilliermondii, two of Candida kefyr, three of Candida krusei, one of Candida lusitaniae, four of Cryptococcus neoformans, five of Candida parapsilosis, six of Candida tropicalis, one of Candida viswanathii, one of Rhodotorula rubra and one of Saccharomyces cerevisiae. According to the reactivity profiles of the isolates, identification was always correct with Fongiscreen 4H and was correct in 97.3% of the strains with Rapidec albicans. The latter test did not identify two C. albicans isolates that were correctly identified by Fongiscreen 4H. Both methods (97.3% correlation) were very useful for identification of C. albicans achieving the aim of their manufacturers. Additionally, Fongiscreen 4H was very useful for the identification of three other species of yeasts: C. glabrata, C. tropicalis and Cr. neoformans. The results of our study indicate that the accuracy of Rapidec albicans and Fongiscreen 4H is similar to that of the conventional methods used in this study for the identification of C. albicans. The same is true of Fongiscreen 4H in the identification of C. glabrata, C. tropicalis and Cr. neoformans. Both tests could be rapid and easy-to-perform tools in the clinical microbiology laboratory, but differences in cost must be taken into account.

Candida↗
PubMed1995

Evaluation of CrystalTM Rapid Stool/Enteric ID System for Identification of Aerobic Gram-negative Bacilli.

OBJECTIVE: The evaluation of the new miniaturized CrystalTM Rapid Stool/Enteric System (Becton-Dickinson, USA) for identification of aerobic gram-negative bacilli. METHODS: a total of 154 clinical organisms (Enterobacteriaceae: 120 strains; oxidase-positive fermenters: 13 strains; non-fermenters: 21 strains) were tested. Results were compared with those obtained with the PASCOR system (Difco, USA) and divergent identifications were evaluated by standard biochemical tests. RESULTS: without additional testing, correct identification was obtained for 146 strains (Enterobacteriaceae: 95%; oxidase-positive fermenters 87%; non-fermenters 100%). For adequate identification of Yersinia enterocolitica strains, however, panels had to be incubated for 5 instead of 3 hours. CONCLUSIONS: the CrystalTM Rapid Stool/Enteric system offers a safe, accurate and rapid method for the identification of frequent isolates of the family Enterobacteriaceae and bacterial stool pathogens.

Journal Article↗
PubMed1997

Comparison of Auxacolor with API 20 C Aux in yeast identification.

OBJECTIVE: To compare Auxacolor with API 20 C Aux for identification of yeasts. METHODS: A total of 206 isolates belonging to 25 species was used in this study. Conventional yeast identification methods were used as a reference. RESULTS: With API 20 C Aux, the correct identification rate was 89.3% after 2 days, while 94.7% of the strains were correctly identified after 3 days. One of 14 strains of Candida tropicalis and 10 of 16 strains of Trichosporon cutaneum were not correctly identified. With Auxacolor, the percentages of correct identification after 1 and 2 days were 60.1% and 69.4%, respectively. Most strains of 11 of the 20 species considered in the system were correctly identified, including several of the most frequent yeast species. Several less commonly encountered yeast species were not correctly identified. Suggestions for improvement of the Auxacolor system are given. CONCLUSIONS: For the most frequent yeast species, Auxacolor, after adaptation and correction of the identification table, provides a useful alternative to API 20 C Aux. For less frequently encountered yeast species, the use of API 20 C Aux is preferable.

Journal Article↗
PubMed2005

Identification of coagulase-negative staphylococci other than Staphylococcus epidermidis by automated ribotyping.

As routine identification of coagulase-negative staphylococci is problematic, the performance of automated ribotyping was evaluated for identification of coagulase-negative staphylococci other than Staphylococcus epidermidis. In total, 177 isolates were tested, comprising 149 isolates from blood samples, 15 isolates that were not identified by internal transcribed spacer (ITS)-PCR in a previous study, and 13 reference strains. The identification results were compared with those obtained by the API 20 Staph system, with standard phenotypic and molecular methods as reference. Most (n = 166; 93.8%) isolates were identified correctly by automated ribotyping. For 61 isolates, API 20 Staph and ribotyping were in agreement, but for 105 isolates, ribotyping provided correct identification and API 20 Staph did not. Four isolates not identified by automated ribotyping were recognised correctly by API 20 Staph. The remaining seven isolates could not be identified by either of the two methods. Automated ribotyping was able to distinguish Staphylococcus capitis reliably from Staphylococcus caprae. The results demonstrate the value of automated ribotyping for identification of coagulase-negative Staphylococcus (CoNS) isolates from human sources and may help to clarify the clinical relevance of CoNS species. In addition, automated ribotyping was able to detect polymorphisms that may be useful for epidemiological purposes within S. capitis, Staphylococcus hominis, Staphylococcus haemolyticus, Staphylococcus simulans, S. caprae, Staphylococcus warneri, Staphylococcus lugdunensis, Staphylococcus schleiferi, Staphylococcus sciuri, Staphylococcus pasteuri and Staphylococcus xylosus.

Phenotype↗
PubMed2005

Rapid identification of Candida spp. in peritonitis patients by Raman spectroscopy.

This prospective study evaluated Raman spectroscopy for the identification of clinically relevant Candida spp. in peritonitis patients. A Raman database was developed by measuring spectra from 93 reference strains belonging to ten different Candida spp. Clinical samples were obtained from the surgical department and intensive care unit of a tertiary university hospital. In total, 88 peritoneal specimens from 45 patients with primary, secondary or tertiary peritonitis were included. Specimens were cultured initially on a selective Sabouraud medium that contained gentamicin to suppress bacterial growth. For conventional identification, a chromogenic medium was used for presumptive identification, followed by use of the Vitek 2 system for definitive identification (requiring a total time of 48-96 h). Raman measurements were taken on overnight cultures from Sabouraud-gentamicin medium. Thirty-one samples were positive for Candida by culture. Using multivariate statistical analyses, a prediction accuracy of 90% was obtained for Raman spectroscopy, which appears to offer an accurate and rapid (12-24 h) alternative for the identification of Candida spp. in peritonitis patients. The reduced turn-around time is of great clinical importance for the treatment of critically ill patients with invasive candidiasis in intensive care units.

Candida↗
PubMed2005

Comparison of bioMérieux API 20NE and Remel RapID NF Plus, identification systems of type strains of Ralstonia pickettii.

UNLABELLED: A : Comparison of two commercial miniaturized rapid systems for the identification of Ralstonia pickettii strains. METHODS AND RESULTS: Varying identification results were encountered using the bioMérieux API NE system and the Remel IDS RapID NF Plus commercial systems for R. pickettii. To compare these two systems, eight strains of R. pickettii were purchased from different commercial culture collections. Additionally, 32 industrial and eight clinical isolates, initially identified using the Vitek Junior (bioMérieux) were tested. Total number of isolates tested was 48. The API 20NE identified 29 isolates, as R. pickettii but was unsuccessful with 19 isolates. The Remel IDS RapID NF Plus identified 46 isolates as R. pickettii. One clinical and one industrial isolates was identified as non-R. pickettii with both systems. CONCLUSIONS: The above results indicate that the use of API 20NE system for examining the identification of R. pickettii strains is inconsistent. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated that the RapID NF Plus is more accurate as an inexpensive identification system for the identification of R. pickettii, a potential emerging organism of medically and industrial importance.

Bacterial Typing Techniques↗
PubMed1999

Routine identification of Campylobacter jejuni and Campylobacter coli from human stool samples.

Correct identification of Campylobacter jejuni and Campylobacter coli isolates to the species or subspecies level is a cumbersome but nevertheless important task for a routine diagnostic laboratory. The widely used biochemical tests might be often misleading while more sophisticated phenotypic or genotypic methods are not generally available. This investigation was performed to assess the performance of common biochemical identification in comparison with species-specific PCR and gas liquid chromatography of whole cell fatty acid extracts (GLC). A total of 150 consecutive isolates from human stool samples were investigated (134 C. jejuni ssp. jejuni, 14 C. coli, two Helicobacter pullorum). From these 144, 145 and 149 isolates were correctly identified by biochemistry, GLC and PCR, respectively. Biochemical identification of all C. jejuni isolates was confirmed by PCR. GLC detected both H. pullorum strains but misidentified two C. coli strains as C. jejuni and one C. jejuni strain as C. coli. No single method can be defined as 'gold standard' for identification of C. jejuni and C. coli but a combination of techniques is needed. Therefore a stepwise identification scheme starting with biochemical reactions is suggested. All results other than C. jejuni should be confirmed by further methods. For indoxyl acetate-positive isolates species-specific PCR is recommended while GLC seems to be advantageous in indoxyl acetate-negative isolates.

Campylobacter coli↗
PubMed1994

Comparison of genotypic and phenotypic methods for species identification of coagulase-negative staphylococcal isolates from blood cultures.

Coagulase-negative staphylococci are often isolated from blood cultures. Simple methods are needed for correct identification of those species most frequently found. In this study, PCR methods were developed for the identification of S. epidermidis and S. haemolyticus, based on DNA sequences in their 16S rDNA. The results obtained by these methods were compared with those obtained using a number of phenotypic methods, including two commercial kits API Staph and Staphzyme. Fifteen type collection strains and 133 blood culture isolates were tested. The sensitivity of the PCR for identification of S. epidermidis was 99% compared with API Staph, but the specificity was lower, 94%, because of positive results also for S. capitis. The results by the PCR for identification of S. haemolyticus correlated closely with the Staphzyme results, 13 isolates being identified by Staphzyme and 16 by the PCR. API Staph, however, identified only four clinical isolates as S. haemolyticus, probably too few. Among the individual phenotypic tests performed, a trehalose-mannitol agar method and a desferrioxamine disc diffusion test for the identification of S. epidermidis were found to be very accurate. Anaerobic growth after overnight incubation could be used to distinguish S. epidermidis from S. hominis. The conclusion is that a majority of all Gram-positive, catalase-positive and coagulase-negative blood culture isolates can be typed as regards species level using only a few genotypic and/or phenotypic tests.

Bacterial Typing Techniques↗
PubMed2001

Feature dependence in the automatic identification of musical woodwind instruments.

The automatic identification of musical instruments is a relatively unexplored and potentially very important field for its promise to free humans from time-consuming searches on the Internet and indexing of audio material. Speaker identification techniques have been used in this paper to determine the properties (features) which are most effective in identifying a statistically significant number of sounds representing four classes of musical instruments (oboe, sax, clarinet, flute) excerpted from actual performances. Features examined include cepstral coefficients, constant-Q coefficients, spectral centroid, autocorrelation coefficients, and moments of the time wave. The number of these coefficients was varied, and in the case of cepstral coefficients, ten coefficients were sufficient for identification. Correct identifications of 79%-84% were obtained with cepstral coefficients, bin-to-bin differences of the constant-Q coefficients, and autocorrelation coefficients; the latter have not been used previously in either speaker or instrument identification work. These results depended on the training sounds chosen and the number of clusters used in the calculation. Comparison to a human perception experiment with sounds produced by the same instruments indicates that, under these conditions, computers do as well as humans in identifying woodwind instruments.

Acoustics↗
PubMed2006

Stimulus variability and the phonetic relevance hypothesis: effects of variability in speaking style, fundamental frequency, and speaking rate on spoken word identification.

Three experiments were conducted to examine the effects of trial-to-trial variations in speaking style, fundamental frequency, and speaking rate on identification of spoken words. In addition, the experiments investigated whether any effects of stimulus variability would be modulated by phonetic confusability (i.e., lexical difficulty). In Experiment 1, trial-to-trial variations in speaking style reduced the overall identification performance compared with conditions containing no speaking-style variability. In addition, the effects of variability were greater for phonetically confusable words than for phonetically distinct words. In Experiment 2, variations in fundamental frequency were found to have no significant effects on spoken word identification and did not interact with lexical difficulty. In Experiment 3, two different methods for varying speaking rate were found to have equivalent negative effects on spoken word recognition and similar interactions with lexical difficulty. Overall, the findings are consistent with a phonetic-relevance hypothesis, in which accommodating sources of acoustic-phonetic variability that affect phonetically relevant properties of speech signals can impair spoken word identification. In contrast, variability in parameters of the speech signal that do not affect phonetically relevant properties are not expected to affect overall identification performance. Implications of these findings for the nature and development of lexical representations are discussed.

Adolescent↗
PubMed1982

Vowel identification: orthographic, perceptual, and acoustic aspects.

This study investigates conditions under which vowels are well recognized and relates perceptual identification of individual tokens to acoustic characteristics. Results support recent finding that isolated vowels may be readily identified by listeners. Two experiments provided evidence that certain response tasks result in inflated error rates. Subsequent experiments showed improved identification in a fixed speaker context, compared with randomized speakers, for isolated vowels and gated centers. Performance was worse for gated vowels, suggesting that dynamic properties (such as duration and diphthongization) supplement steady-state cues. However, even-speaker-randomized gated vowels were well identified (14% errors). Measures of "steady-state information" (formant frequencies and f0), "dynamic information" (formant slopes and duration), and "speaker information" (normalization) were adopted. Discriminant analyses of acoustic measurements indicated relatively little overlap between vowel categories. Using a new technique for relating acoustic measurements of individual tokens with identification by listeners, it is shown that (a) identification performance is clearly related to acoustic characteristics; (b) improvement in the fixed speaker context is correlated with improved statistical separation resulting from formant normalization, for the gated vowels; and (c) "dynamic information" is related to identification differences between full and gated isolated vowels.

Adolescent↗
PubMed1987

Comparative learning of pitch and loudness identification.

This study investigated possible similarities between the ability to identify pitches and the ability to identify loudnesses. Systematic training of musically naive subjects indicated that frequency identification performance improves at about the same rate as intensity identification performance. Examination of frequency and intensity identification behavior of musically trained subjects showed that their ability to code pitch information efficiently does not generalize to an ability to encode loudness information more efficiently than untrained subjects. Intensity identification training curves of musically trained and untrained subjects are similar, but final performance levels are below frequency identification performance levels exhibited by musically trained subjects, especially those with absolute pitch.

Discrimination Learning↗
PubMed1987

Minimum spectral contrast for vowel identification by normal-hearing and hearing-impaired listeners.

To determine the minimum difference in amplitude between spectral peaks and troughs sufficient for vowel identification by normal-hearing and hearing-impaired listeners, four vowel-like complex sounds were created by summing the first 30 harmonics of a 100-Hz tone. The amplitudes of all harmonics were equal, except for two consecutive harmonics located at each of three "formant" locations. The amplitudes of these harmonics were equal and ranged from 1-8 dB more than the remaining components. Normal-hearing listeners achieved greater than 75% accuracy when peak-to-trough differences were 1-2 dB. Normal-hearing listeners who were tested in a noise background sufficient to raise their thresholds to the level of a flat, moderate hearing loss needed a 4-dB difference for identification. Listeners with a moderate, flat hearing loss required a 6- to 7-dB difference for identification. The results suggest, for normal-hearing listeners, that the peak-to-trough amplitude difference required for identification of this set of vowels is very near the threshold for detection of a change in the amplitude spectrum of a complex signal. Hearing-impaired listeners may have difficulty using closely spaced formants for vowel identification due to abnormal smoothing of the internal representation of the spectrum by broadened auditory filters.

Adult↗
PubMed1981

Biochemical characteristics and identification of Enterobacteriaceae isolated from meats.

The isolation and identification of 2,220 Enterobacteriaceae from meats indicated that Escherichia coli biotype I, Enterobacter agglomerans, and Serratia liquefaciens were the principal types to be differentiated in meats. Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae, and Enterobacter hafniae were also commonly identified. Identification of isolates by the Encise II (Roche Diagnostics Inc., Nutley, N.J.) and Minitek (BBL Microbiology Systems, Cockeysville, Md.) coding systems gave similar results with only 255 (11.5%) discrepancies in identity, but both systems required large numbers of supplementary tests for identification of the isolates. Not only the distribution of Enterobacteriaceae types isolated from meats but also some of the biochemical reactions of the isolates differed from those of clinical isolates. The Minitek technique is recommended because of its versatility. However, with the addition of cellobiose and salicin disks and the inclusion of methyl red to the Minitek test and the use of the Voges-Proskauer test and gas production in EC medium at elevated temperature as standard tests, the identification of these Enterobacteriaceae from meats would be greatly facilitated. The inclusion of the motility test, for example, using nitrate motility agar, would also be of value to Enterobacteriaceae identification.

Carbohydrate Metabolism↗
PubMed1991

Comparative study on the identification of food-borne yeasts.

Morphologically distinct yeast colonies from partially and fully processed fruits and vegetables were isolated over a 3-year period. Identification of 239 strains was achieved by using standard methods, commercial identification kits (API 20C and API YEAST-IDENT), and a simplified system for food-borne yeasts. The identified strains of fruit origin represented 36 species belonging to 19 genera. Among strains of vegetable origin, 34 species representing 17 genera were identified. The simplified identification system and the conventional method provided the same results in 80% of the cases. The commercial identification kits were easy to use but were not appropriate for food-borne yeast species. Computer-assisted identification was helpful.

Food Microbiology↗
PubMed2002

Fourier-transform infrared microspectroscopy, a novel and rapid tool for identification of yeasts.

Fourier-transform infrared (FT-IR) microspectroscopy was used in this study to identify yeasts. Cells were grown to microcolonies of 70 to 250 micro m in diameter and transferred from the agar plate by replica stamping to an IR-transparent ZnSe carrier. IR spectra of the replicas on the carrier were recorded using an IR microscope coupled to an IR spectrometer, and identification was performed by comparison to reference spectra. The method was tested by using small model libraries comprising reference spectra of 45 strains from 9 genera and 13 species, recorded with both FT-IR microspectroscopy and FT-IR macrospectroscopy. The results show that identification by FT-IR microspectroscopy is equivalent to that achieved by FT-IR macrospectroscopy but the time-consuming isolation of the organisms prior to identification is not necessary. Therefore, this method also provides a rapid tool to analyze mixed populations. Furthermore, identification of 21 Debaryomyces hansenii and 9 Saccharomyces cerevisiae strains resulted in 92% correct identification at the strain level for S. cerevisiae and 91% for D. hansenii, which demonstrates that the resolution power of FT-IR microspectroscopy may also be used for yeast typing at the strain level.

Microbiological Techniques↗
PubMed2002

Direct identification in food samples of Listeria spp. and Listeria monocytogenes by molecular methods.

A new molecular approach for the detection and identification of Listeria spp. and Listeria monocytogenes in food is presented here. The method is based on the PCR amplification of a fragment of the iap gene from the five species belonging to the genus and on the analysis of the PCR products obtained by denaturing gradient gel electrophoresis (DGGE). The protocol was first optimized by using strains from international collections. Based on the differences present in the sequences amplified, it was possible to obtain species-specific DGGE migration that allowed fast and easy identification of L. monocytogenes, L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii. Moreover, for L. monocytogenes serotypes, partial differentiation was possible. The optimized protocol was used for identification of Listeria strains traditionally isolated from food and for direct detection and identification of Listeria members in food after an overnight enrichment. Identification of 48 food isolates and direct detection of Listeria spp. in 73 food samples show the potential of the method that can be used as a fast screening test to investigate the presence of Listeria spp. and L. monocytogenes in food.

Bacterial Proteins↗