Detection Frequencies (detection + frequency)

Distribution by Scientific Domains


Selected Abstracts


Aroma-impact compounds in Lysimachia foenum-graecum extracts

FLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2009
Na Shu
Abstract Two different extraction methods were used to obtain representative extracts from stems and leaves of Lysimachia foenum-graecum, a Chinese plant with a smoky, spicy, green, woody and caramel aroma. An extract was obtained by steam distillation followed by pentane back-extraction. Plants were also extracted with dichloromethane, and the non-volatile compounds were separated from volatiles by high-vacuum distillation (SAFE). Compared to the steam distillate extract, the SAFE-distilled extract was judged to be more similar to the aroma of the starting materials. The aroma-impact compounds of the SAFE extract were then determined using multidimensional GC. From the detection frequencies and the intensities of the peaks, 47 peaks with odour-activity were determined, using an adaptation of the GC,SNIFF method, to have an impact on the overall aroma of the extract. Fifty-four compounds responsible for the peaks presenting odour-activity were identified from mass spectral data, retention indices, olfactory character and co-injection of authentic standards. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Effects of Land Use on Ground Water Quality in the Anoka Sand Plain Aquifer of Minnesota

GROUND WATER, Issue 4 2003
Michael D. Trojan
We began a study, in 1996, to compare ground water quality under irrigated and nonirrigated agriculture, sewered and nonsewered residential developments, industrial, and nondeveloped land uses. Twenty-three monitoring wells were completed in the upper meter of an unconfined sand aquifer. Between 1997 and 2000, sampling occurred quarterly for major ions, trace inorganic chemicals, volatile organic compounds (VOCs), herbicides, and herbicide degradates. On single occasions, we collected samples for polynuclear aromatic hydrocarbons (PAHs), perchlorate, and coliform bacteria. We observed significant differences in water chemistry beneath different land uses. Concentrations of several trace inorganic chemicals were greatest under sewered urban areas. VOC detection frequencies were 100% in commercial areas, 52% in sewered residential areas, and <10% for other land uses. Median nitrate concentrations were greatest under irrigated agriculture (15,350 ,g/L) and nonsewered residential areas (6080 ,g/L). Herbicides and degradates of acetanilide and triazine herbicides were detected in 86% of samples from irrigated agricultural areas, 68% of samples from nonirrigated areas, and <10% of samples from other land uses. Degradates accounted for 96% of the reported herbicide mass. We did not observe seasonal differences in water chemistry, but observed trends in water chemistry when land use changes occurred. Our results show land use is the dominant factor affecting shallow ground water quality. Trend monitoring programs should focus on areas where land use is changing, while resource managers and planners must consider potential impacts of land use changes on ground water quality. [source]


Microbiological shifts in intra- and extraoral habitats following mechanical periodontal therapy

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2004
Thomas Beikler
Abstract Objectives: The aim of the present study was to analyze the intra- and extraoral colonization dynamics of periodontal pathogens following supra- and subgingival debridement. Material and Methods: Thirty five patients with chronic periodontitis were enrolled in the study. Supra- and subgingival plaque samples, saliva, and swab samples from mucosa and extraoral sites were taken at baseline and 6 weeks, 3 months and 6 months after mechanical periodontal therapy. Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Eikenella corrodens (Ec), Tannerella forsythensis (Tf), Prevotella intermedia (Pi), Prevotella nigrescens (Pn), and Treponema denticola (Td) were identified by PCR. Results: Supra- and subgingival debridement decreased the number of subgingival sites infected with the analyzed pathogens only transiently, if at all. However, the detection frequencies of Tf, Td, Ec, Pi, and Pn in the supragingival region, of Pg, Td, and Pn at the oral mucosa sites (mostly the tongue), and of all pathogens except Aa in saliva increased over the 6-month observation period. Td was the only pathogen recorded in notable quantities in the extraoral habitat (external ear canal). Conclusion: The results indicate that supra- and subgingival debridement results in a dissemination of periodontal pathogens within the oral cavity. [source]


VOLATILE ORGANIC COMPOUNDS IN GROUND WATER FROM RURAL PRIVATE WELLS, 1986 TO 1999,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 5 2004
Michael J. Moran
ABSTRACT: The U.S. Geological Survey (USGS) collected or compiled data on volatile organic compounds (VOCs) in samples of untreated ground water from 1,926 rural private wells during 1986 to 1999. At least one VOC was detected in 12 percent of samples from rural private wells. Individual VOCs were not commonly detected with the seven most frequently detected compounds found in only 1 to 5 percent of samples at or above a concentration of 0.2 microgram per liter (,g/l). An assessment level of 0.2 ,g/l was selected so that comparisons of detection frequencies between VOCs could be made. The seven most frequently detected VOCs were: trichloromethane, methyl tert -butyl ether, tetrachloroethene, dichlorodifluoromethane, methylbenzene, 1,1,1-trichloroethane, and 1,2-dibromo-3-chloropropane. Solvents and trihalomethanes were the most frequently detected VOC groups in private wells. The distributions of detections of gasoline oxygenates and fumigants seemed to be related to the use patterns of compounds in these groups. Mixtures were a common mode of occurrence of VOCs with one-quarter of all samples with detections including two or more VOCs. The concentrations of most detected VOCs were relatively small and only 1.4 percent of samples had one or more VOC concentrations that exceeded a federally established drinking water standard or health criterion. [source]


Microbiological and clinical outcomes and patient satisfaction for two treatment options in the edentulous lower jaw after 10 years of function

CLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2005
Marc Quirynen
Abstract Background: Long-term data on microbiological and clinical outcome as well as on patient satisfaction after implant therapy in the edentulous mandible are limited. Especially comparisons between fixed full prostheses (FFPs) and overdentures (ODs), or between anchoring systems for the latter are scarce. Aim: This study aimed to evaluate both of these parameters at the 10-year follow-up in a group of fully edentulous patients rehabilitated via an OD or a FFP (the latter to allow inter-group comparison). Material and methods: A total of 37 fully edentulous patients (25 ODs, 12 FFPs, age at implant installation ranged from 36 to 85 years) participated in this study. All subjects received their implants (Brånemark System®, Nobel Biocare AB, Gothenburg, Sweden) 10 years previously. For the ODs different attachment systems (bar, magnets, ball) had been applied that allowed a further intra-group comparison. At the follow-up visit, 10 years after the abutment insertion, a series of periodontal parameters were recorded, long-cone radiographs were taken and subgingival plaque samples were collected for analysis using checkerboard DNA,DNA hybridization. The clinical and radiographic data were recorded at abutment connection and after 1 and 10 years. Results: After 10 years of loading, mean plaque and bleeding indices and changes in attachment or marginal bone level were not significantly different, neither between the OD and FFP group, nor within the OD group. The marginal bone loss between abutment connection and year 10 was 0.86 and 0.73 mm for OD and FFP groups, respectively. The subgingival microbiota at implant sites from all (sub)-groups was comparable, with low numbers of DNA counts (±10 × 105) but high detection frequencies of Actinobacillus actinomycetemcomitans (>90%), Porphyromonas gingivalis (>85%) and Tannerella forsythensis (30%). The composition of the subgingival microbiota was influenced by probing depth and bleeding tendency. Patient satisfaction was very high for both types of prosthetic rehabilitation. The FFP group scored only slightly better for chewing comfort and general satisfaction. Conclusion: These data indicate that from the clinical and microbiological standpoint, as well as patient satisfaction, both an OD and a FFP offer a favourable long-term outcome. Résumé Les données à long terme de la guérison clinique et microbiologique ainsi que la satisfaction du patient après un traitement par implants dans la mandibule édentée sont limitées. Essentiellement des comparaisons entre les prothèses fixées complètes et les prothèses fixées amovibles ou entre les systèmes d'ancrage pour ces derniers sont rares. Cette étude a eu pour but d'évaluer ces paramètres après dix ans dans un groupe de patients complètement édentés qui avaient été soignés par une prothèse amovible ou fixée (cette dernière pour permettre la comparaison intergroupes). Trente-sept patients édentés [25 prothèses amovibles (OD), douze prothèses fixées (FFP), l'âge au moment du placement des implants était de 36 à 85 ans] ont participéà cette étude. Tous les sujets avaient reçu des implants Brånemark® 10 ans auparavant. Pour les prothèses amovibles, différents types d'attache (balle, aimant) avaient été utilisés, ce qui permettaient une comparaison intragroupe supplémentaire. Lors de la visite du suivi, dix ans après l'insertion des implants, une série de paramètres parodontaux ont été enregistrés, des radiographies par long cône prises et des échantillons de plaque sous-gingivale prélevés pour l'analyse utilisant l'hybridisation ADN-ADN échiquier. Les données cliniques et radiographiques ont été enregistrées au moment de la connexion de l'implant et après une et dix années. Dix années après la mise en charge, les indices de plaque et de saignement et les variations dans l'attache ou les niveaux osseux marginaux n'étaient pas significativement différents ni entre les groupes OD et FFP ni à l'intérieur du groupe OD. La perte osseuse marginale entre les connexions des piliers et dix ans après étaient respectivement de 0,86 et 0,73 mm pour les groupes OD et FFP. La flore sous-gingivale au niveau des implants pour tous les groupes et sous-groupes étaient semblables avec de faibles comptages ADN (±10 × 105) mais des fréquences de détection importantes de A. actinomycetemcomitans (>90%), P. gingivalis (>85%) et T.forsythensis (30%). La composition de la flore sous-gingivale a été influencée par la profondeur de la poche et la tendance au saignement. La satisfaction du patient était très élevée pour les deux types de prothèses. Le groupe FFP n'était qu'un petit peu meilleur pour le confort à la mastication et la satisfaction générale. Ces données indiquent que d'un point de vue clinique et microbiologique autant que d'un point de vue de satisfaction du patient les prothèses amovibles et fixées sont favorables à long terme. Zusammenfassung Hintergrund: Die Langzeitresultate über den mikrobiologischen und klinischen Verlauf und über die Zufriedenheit der Patienten nach Implantatversorgung im zahnlosen Unterkiefer sind limitiert. Im Speziellen sind Vergleiche zwischen festsitzenden totalen Brücken und Hybridprothesen und den verschiedenen Befestigungssystemen für Hybridprothesen selten. Ziel: Das Ziel der Studie war, beide Parameter anlässlich der Nachuntersuchung nach 10 Jahren bei einer Gruppe von zahnlosen Patienten, welche mit einer Hybridprothese oder mit einer festsitzenden Brücke wiederhergestellt worden waren, auszuwerten (bei den Hybridprothesen sollten auch Vergleiche innerhalb der Gruppe durchgeführt werden). Material und Methoden: Insgesamt nahmen 37 zahnlose Patienten an der Studie teil (25 Hybridprothesen (OD), 12 festsitzende Prothesen (FFP), Alter zum Zeitpunkt der Implantation 36 bis 85 Jahre). Alle Subjekte hatte vor 10 Jahren ihre Implantate erhalten (Brånemark System®, Nobel Biocare, Schweden). Bei den Hybridprothesen waren verschiedene Befestigungssysteme verwendet worden (Steg, Magnet, Kugeln). Dies erlaubte Vergleiche innerhalb der Gruppe. Bei der Nachuntersuchung 10 Jahre nach Einsetzten der Prothetikteile wurden parodontale Parameter aufgenommen, Röntgenbilder mit der Langkonustechnik angefertigt und subgingivale Plaqueproben zur Analyse mittels Ceckerboard DNA,DNA Hybridisierung entnommen. Die klinischen und radiologischen Daten wurden beim Einsetzten der Prothetikteile und nach 1 und 10 Jahren aufgenommen. Resultate: Nach 10 Jahren Belastung bestanden weder zwischen der OD und FFP Gruppe, noch innerhalb der OD Gruppe statistisch signifikante Unterschiede im mittleren Plaque- und Blutungsindex und in der Attachment- und marginalen Knochenhöhe. Der Verlust an marginalem Knochen zwischen der Montage der Prothetikteile und nach 10 Jahren betrug 0.86 mm für die OD Gruppe und 0.73 mm für die FFP Gruppe. Die subgingivale Flora war bei allen Implantatstellen der (Sub-) Gruppen vergleichbar. Es bestand eine geringe Anzahl an DNA Zählungen (±10 × 105) aber eine hohe Entdeckungsfrequenz für A. actinomycetemcomitans (>90%), P. gingivalis (>85%) und T. forsythensis (30%). Die Zusammensetzung der subgingivalen Mirkoflora wurde durch die Sondierungstiefe und die Blutungstendenz beeinflusst. Die Zufriedenheit der Patienten war für beide Arten der prothetischen Wiederherstellung sehr hoch. Die FFP Gruppe erreichte nur geringfügig bessere Werte bezüglich Kaukomfort und genereller Zufriedenheit. Schlussfolgerung: Diese Daten zeigen, dass sowohl vom klinischen und mikrobiologischen Standpunkt aus als auch seitens der Patientenzufriedenheit die Hybridprothese und die festsitzende totale Brücke gute Langzeitresultate zeigen. Resumen Antecedentes: Los datos a largo plazo sobre los resultados microbiológicos y clínicos al igual que la satisfacción del paciente tras la terapia de implantes en la mandíbula edéntula son limitados. Son especialmente escasas las comparaciones entre prótesis fija completa y sobredentaduras, o entre sistemas de anclaje. Intención: Este estudio se intentó para evaluar ambos parámetros en el control de seguimiento de los 10 años en un grupo de pacientes totalmente edéntulos rehabilitados por medio de una sobredentadura o una prótesis completa fija (la última para permitir comparaciones intergrupo). Material y métodos: Un total de 37 pacientes totalmente edéntulos (25 sobredentaduras (OD), 12 prótesis completas fijas (FFP), la edad en el momento de la implantación varió entre 36 a 85 años) participaron en este estudio. Todos los sujetos recibieron sus implantes (Brånemark System®, Nobel Biocare, Suecia) 10 años antes. Para las sobredentaduras se aplicaron diferentes sistemas de anclaje (barras, imanes, bolas) lo que permitieron una ulterior comparación intragrupo. En la visita de seguimiento, 10 años tras la colocación de los pilares, se recogieron una serie de parámetros periodontales, se tomaron radiografías de cono largo y se recogieron muestras de la placa subgingival para análisis usando la cuadrícula de DNA-DNA hibridación. Los datos clínicos y radiográficos se recogieron al conectar los pilares y tras 1 y 10 años. Resultados: Tras 10 años de carga, los índices medios de placa y sangrado y los cambios en el nivel óseo marginal y de inserción no fueron significativos, ni entre los grupos OD y FFP, ni dentro del grupo OD. La pérdida de hueso marginal entre la conexión de los pilares y el año 10 fue de 0.86 y 0.73 mm para los grupos OD y FFP, respectivamente. La microflora subgingival en los lugares de implantes fue comparable entre todos los (sub)-grupos, con un bajo recuento de DNA (±10 × 105) pero una alta detección de A. actinomycetemcomitans (>90%), P. gingivalis (>85%) y T. forsythensis (30%). La composición de la microflora subgingival fue influida por la profundidad de sondaje y la tendencia al sangrado. La satisfacción de los pacientes fue muy alta para ambos grupos de rehabilitación protésica. El grupo FFP puntuó solo un poco mejor para la satisfacción masticatoria y satisfacción general. Conclusión: Estos datos indican que desde el punto de vista clínico y microbiológico al igual que la satisfacción del paciente, tanto la sobredentadura como la prótesis completa fija ofrecen unos resultados favorables a largo plazo. [source]


Detection of denitrification genes by in situ rolling circle amplification-fluorescence in situ hybridization to link metabolic potential with identity inside bacterial cells

ENVIRONMENTAL MICROBIOLOGY, Issue 9 2010
Tatsuhiko Hoshino
Summary A target-primed in situ rolling circle amplification (in situ RCA) protocol was developed for detection of single-copy genes inside bacterial cells and optimized with Pseudomonas stutzeri, targeting nitrite and nitrous oxide reductase genes (nirS and nosZ). Two padlock probes were designed per gene to target both DNA strands; the target DNA was cut by a restriction endonuclease close to the probe binding sites, which subsequently were made accessible by 5,-3, exonucleolysis. After hybridization, the padlock probe was circularized by ligation and served as template for in situ RCA, primed by the probe target site. Finally, the RCA product inside the cells was detected by standard fluorescence in situ hybridization (FISH). The optimized protocol showed high specificity and signal-to-noise ratio but low detection frequency (up to 15% for single-copy genes and up to 43% for the multi-copy 16S rRNA gene). Nevertheless, multiple genes (nirS and nosZ; nirS and the 16S rRNA gene) could be detected simultaneously in P. stutzeri. Environmental application of in situ RCA-FISH was demonstrated on activated sludge by the differential detection of two types of nirS -defined denitrifiers; one of them was identified as Candidatus Accumulibacter phosphatis by combining in situ RCA-FISH with 16S rRNA-targeted FISH. While not suitable for quantification because of its low detection frequency, in situ RCA-FISH will allow to link metabolic potential with 16S rRNA (gene)-based identification of single microbial cells. [source]


Quadrant root planing versus same-day full-mouth root planing

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2 2004
II. Microbiological findings
Abstract Objectives: The aim of this study was to test the hypothesis that over a period of 6 months, same-day full-mouth scaling and root planing (FM-SRP) resulted in greater reductions in the detection frequency of five putative periodontal pathogens compared with quadrant scaling and root planing (Q-SRP) in chronic periodontitis patients. Materials and Methods: Forty patients were recruited into this study. Subjects were randomised into two groups. The FM-SRP group received full-mouth scaling and root planing completed within the same day, while the Q-SRP group received quadrant root planing at 2-weekly intervals over four consecutive sessions. Selected-site analyses were performed on the deepest site in each quadrant before and after therapy, at approximately 3 and 6 months from baseline (R1 and R2) and clinical indices were recorded with an electronic pressure-sensitive probe. In addition, subgingival plaque samples were collected from these sites at baseline (BAS), at reassessment 1 (R1), approximately 6 weeks after the completion of therapy and at reassessment 2 (R2), 6 months from baseline. Polymerase chain reaction (PCR) was used to determine the presence of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia, Treponema denticola and Bacteroides forsythus in plaque. Results: Both therapies resulted in significant improvements in all clinical indices both at R1 and R2. A marked reduction in the presence of all candidate periodontal pathogens was noted after both treatment modalities, reaching statistical significance for the majority of the test organisms. These improvements were maintained over a period of 6 months. When the two treatment groups were compared, a significantly higher percentage of Q-SRP patients was positive for P. intermedia at R1 compared with FM-SRP patients (p<0.05). In addition, a greater reduction in the patient prevalence for T. denticola was found for the FM-SRP group than the Q-SRP group at R1 and R2 from baseline (p<0.005), but the significance of this is questionable given the skewed detection frequency of this organism at baseline between the two treatments (p<0.01). Conclusion: This study failed to confirm that same-day FM-SRP resulted in greater microbiological improvements compared with Q-SRP at 2-weekly intervals over a 6-month period, as determined by PCR. [source]


Comparative analysis of putative periodontopathic bacteria by multiplex polymerase chain reaction

JOURNAL OF PERIODONTAL RESEARCH, Issue 3 2008
M. Morikawa
Background and Objective:, The polymerase chain reaction (PCR) has been applied for the rapid and specific detection of periodontopathic bacteria in subgingival plaque and is potentially of clinical benefit in the diagnosis and treatment of periodontitis subjects. However, several technical points need to be modified before the conventional PCR detection system can be used by clinicians. Material and Methods:, To develop a PCR-based technique more applicable for clinical use than conventional PCR, we established a multiplex PCR for five putative periodontopathic (Treponema denticola, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Tannerella forsythia) and two nonperiodontopathic (Streptococcus sanguinis and Streptococcus salivarius) species of bacteria using whole-plaque suspension as templates, and detected bacteria in subgingival plaque taken from 85 subjects at the supportive periodontal therapy stage after active periodontal treatments. Results:, Among putative periodontopathic bacteria, the detection frequency of T. denticola and P. gingivalis was elevated in parallel with higher probing pocket depth and clinical attachment loss, and had 4.2,14.1 times increasing odds of the clinical parameters tested. Detection of any of the five species of putative periodontopathic bacteria markedly increased the odds ratio of a higher probing pocket depth, clinical attachment loss and bleeding on probing. Conclusion:, The multiplex PCR system developed in this study enabled the detection of all the bacteria under investigation in one reaction tube in a less time- and labor-intensive manner than conventional PCR. These results support the potential clinical use of multiplex PCR for detecting periodontopathic bacteria and for evaluating therapeutic strategies and predicting the prognosis for each subject. [source]