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Probe Tip (probe + tip)

Distribution by Scientific Domains

Medical Sciences	69%

Selected Abstracts

Localized "Click" Chemistry Through Dip-Pen Nanolithography,

ADVANCED MATERIALS, Issue 24 2007
A. Long
Local reactions are triggered by delivering molecules from an AFM probe tip, allowing for direct modification of chemically functionalized surfaces. Silicon wafer-bound acetylene moieties readily undergo 1,3-dipolar cycloadddition with solution-phase azides delivered from an AFM tip. This selective and robust technique allows for the facile creation and placement of sub-micrometer-sized features. [source]

Comparison of the validity of periodontal probing measurements in smokers and non-smokers

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2001
A. J. Biddle
Abstract Aim: To determine whether the reduced inflammation and bleeding and increased fibrosis reported in tobacco smokers affect the validity of clinical probing measurements by altering probe tip penetration. Method: A constant force probe was used to measure probing depths and sound bone levels at six sites on 64 molar teeth (384 sites) in 20 smoking and 20 non-smoking patients from grooves made with a bur at the gingival margin prior to extraction. Connective tissue attachment levels were measured from the grooves with a dissecting microscope following extraction. Data were analysed using robust regression with sites clustered within subjects. Results: Sites in smokers showed more calculus but less bleeding than sites in non-smokers (p<0.05). The mean clinical probing depth was not significantly different (smokers: 5.54 mm, confidence intervals=4.81 to 6.28; non-smokers: 6.05 mm, ci=5.38 to 6.72). The corresponding post-extraction pocket depth measurements (smokers: 4.95 mm, ci=4.30 to 5.61; non-smokers: 5.23 mm, ci=4.49 to 5.96) were less than clinical probing depth in sites from both smokers and non-smokers (p<0.01). However, the proportional difference was less in smokers (p<0.05), particularly in deeper pockets, indicating that clinical probe tip penetration of tissue was greater in non-smokers. Regression analysis indicated that the presence of calculus and bleeding also influenced the difference in clinical probe penetration (p<0.05). Conclusion: Clinical probing depth at molar sites exaggerates pocket depth, but the probe tip may be closer to the actual attachment level in smokers due to less penetration of tissue. This may be partly explained by the reduced inflammation and width of supra-bony connective tissue in smokers. These findings have clinical relevance to the successful management of periodontal patients who smoke. Zusammenfassung Ziel: Bestimmung, ob die reduzierte Entzündung und Blutung und verstärkte Fibrosierung, die bei Rauchern berichtet wird, die Gültigkeit der klinischen Messung der Sondierungstiefen durch Veränderung der Penetration der Sondenspitze beeinflußt. Methoden: Eine konstante Sondierungskraft wurde genutzt, um die Sondierungstiefen und das Knochenniveau (sounding) an 6 Flächen von 64 Molaren (384 Flächen) bei 20 Rauchern und 20 Nichtrauchern von einer Furche, die mit einem Fräser in der Höhe des gingivalen Randes vor der Extraktion angelegt wurde, zu messen. Das Niveau des bindegewebigen Attachments wurde von der Furche mit einem trennenden Mikroskop nach der Extraktion gemessen. Die Daten wurden unter Nutzung einer robusten Regission mit den Flächen in den Personen zusammengefaßt analysiert. Ergebnisse: Die Flächen von Rauchern zeigten mehr Zahnstein, aber weniger Blutung als die Flächen von Nichtrauchern (p<0.05). Die mittleren Sondierungstiefen unterschieden sich nicht signifikant (Raucher: 5.54 mm, Konfidenzinterval (ci)=4.81 zu 6.28; Nichtraucher: 6.05 mm, ci=5.38 zu 6.72). Die korrespondierenden Taschenmessungen nach der Extraktion (Raucher: 4.95 mm, ci=4.30 zu 5.61; Nichtraucher: 5.23 mm, ci=4.49 zu 5.96) waren geringer als die klinischen Messungen sowohl bei den Flächen bei Rauchern als auch bei Nichtrauchern (p<0.01). Jedoch war die proportionale Differenz bei Rauchern geringer (p<0.05), besonders bei tiefen Taschen, was zeigt, daß die Penetration der Sonde ins Gewebe bei der klinischen Messung bei Nichtrauchern größer war. Die Regressionsanalyse zeigte, daß das Vorhandensein von Zahnstein und Blutung die Differenz in der klinischen Sondenpenetration beeinflußte (p<0.05). Zusammenfassung: Die klinische Sondierung an Molarenflächen überschätzt die Taschentiefe, aber die Sondenspitze liegt bei Rauchern näher am wirklichen Stützgewebelevel aufgrund der geringeren Gewebepenetration. Dies mag teilweise durch die reduzierte Entzündung und die Breite des supra-alveolären Bindegewebes bei Rauchern erklärt werden. Diese Ergebnisse haben klinische Bedeutung bei der erfolgreichen Behandlung von rauchenden parodontalen Patienten. Résumé But: L'objectif de cette étude est de déterminer si la diminution de l'inflammation et du saignement, ainsi que l'augmentation de la fibrose rapportées chez les fumerus affecte la validité des mesures de sondage parodontal en modifiant la pénétration de la sonde. Methode: Une sonde a pression constante a été utilisée pour mesurer la profondeur au sondage et pour sonder le niveau osseux sur les 6 sites de 64 molaires (384 sites) chez 20 patients fumeurs et 20 patients non-fumeurs à partir de rainures faites à la fraise au niveau de la gencive marginale avant extraction. Les niveaux d'attache du tissus conjonctif furent mesurés à partir de la rainure sous microscope de dissection après extraction. Les données furent analysées par régression avec les sites groupés par patients. Résultats: Les sites des fumerus montraient plus de tartre mais moins de saignement que les sites des non-fumeurs (p<0.05). La profondeur moyenne de sondage clinique n'était pas significativement différente (fumeurs: 5.54 mm, interval de confiance=4.81 à 6.28; non-fumeurs: 6.05 mm, ci=5.38 à 6.72). Les mesures de profondeur de poche correspondantes aprés extraction (fumeurs: 4.95 mm, interval de confiance=4.30 à 5.61; non-fumeurs: 5.23 mm, ci=4.49 à 5.96) ètaient moindre que les profondeurs de sondage clinique des sites des fumeurs et des non-fumeurs ensemble (p<0.01). Cependant, la différence proportionnelle était moindre chez les fumeurs (p<0.05), particulièrement pour les poches profondes, ce qui indique que la pénétration tissulaire de la pointe de la sonde était plus importante chez les non-fumeurs. L'analyse de régression indique que la présence de tartre et le saignement influencent aussi la différence clinique de pénétration (p<0.05). Conclusion: La profondeur clinique de sondage sur des sites molaires exaggère la profondeur de poche, mais la pointe de la sonde pourrait être plus proche de l'actuel niveau d'attache chez les fumeurs en raison de la moindre pénétration des tissus. Cela peut être partiellement expliqué par l'inflammation réduite et l'épaisseur du tissus conjonctif supra-osseux chez les fumeurs. Ces résultats ont une signification clinique pour la bonne gestion des patients fumeurs atteints de maladies parodontales. [source]

The accuracy of the Vivacare true pressure-sensitive periodontal probe system in terms of probing force

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2 2000
Axel Bergenholtz
Abstract Background: The Hunter TPS Vivacare periodontal probe was invented to perform consistent, accurate and reliable periodontal examinations "with controlled pressures". Aims: The aims of the present investigation are 3: (1) what is the accuracy of the probing force when various probe heads are used in a correct operation position; (2) what is the effect of over- and under-reading of the operation position on the probing force; (3) what is the accuracy of the probing force when different probe handles are used. The Hunter TPS probe consists of a tip connected to a special spring mechanism, which controls the pressure extended to the probe tip. According to the manufacturer, the force indicator lines coincide at approximately 20 g force. Method: The test apparatus consisted of an electronic balance, and an electronic caliper. 12 TPS probes tips and 3 handles were selected to test whether there were differences in force between probes. Each probe tip was adapted to the same handle and tested 10 times. In a 2nd test, the TPS-handles and over-, accurate-, and under-readings were analyzed as to how they affect the probing force. The 12 TPS probe tips were connected to each of the 3 handles and tested 10× for each of 3 handles and levels. Results: The range in force between TPS probe tips was 8.4 g (p<0.001). For the handles as well as for each of the readings of the operating positions, the differences were small and non-significant. However, between over- and under-readings, there were statistical significant differences. Conclusions: The conclusion is that the variation in force between probe tips is high and always above the manufacturer's "approximately" 20 g. As long as the same handle and the same probe tip are used together, and the examiner is reading the markings correct, the. TPS probe is adequate. [source]

Fabrication of near-field optical apertures in aluminium by a highly selective corrosion process in the evanescent field

JOURNAL OF MICROSCOPY, Issue 3 2003
D. Haefliger
Summary A simple, one-step process to fabricate high-quality apertures for scanning near-field optical microscope probes based on aluminium-coated silicon nitride cantilevers is presented. A thin evanescent optical field at a glass,water interface was used to heat the aluminium at the tip apex due to light absorption. The heat induced a breakdown of the passivating oxide layer and local corrosion of the metal, which selectively exposed the front-most part of the probe tip from the aluminium. Apertures with a protruding silicon nitride tip up to 72 nm in height were fabricated. The height of the protrusion was controlled by the extent of the evanescent field, whereas the diameter depended on the geometry of the probe substrate. The corrosion process proved to be self-terminating, yielding highly reproducible tip heights. Near-field optical resolution in a transmission mode of 85 nm was demonstrated. [source]

In vitro evaluation of Er:YAG laser scaling of subgingival calculus in comparison with ultrasonic scaling

JOURNAL OF PERIODONTAL RESEARCH, Issue 5 2000
A. Aoki
The purpose of the present study was to evaluate the effectiveness of Er:YAG laser scaling and the morphological and histological changes of the laser-scaled root surface in comparison with the effectiveness and root surface changes produced by conventional ultrasonic scaling. Fifty-three periodontally involved human extracted teeth with a band of subgingival calculus were used. The teeth were divided randomly into 2 groups for laser scaling and ultrasonic scaling. Laser irradiation was performed at an energy output of 40 mJ/pulse and 10 pulses/s under water spray, with the probe tip contacted obliquely to the root surface. Ultrasonic scaling was performed at a clinically standard power setting. The time required for scaling, the scaled area and the temperature changes were determined using both methods of treatment. The features of the scaled surfaces were examined by histological and scanning electron microscope (s.e.m.) observations. The Er:YAG laser provided subgingival calculus removal on a level equivalent to that provided by the ultrasonic scaler, without major thermal elevation. Macroscopically, the laser-treated root surface was somewhat rougher than or similar to the ultrasonically scaled root. However, the efficiency of the laser scaling was lower than that of the ultrasonic scaling. In addition, histological examination revealed a thin deeply stained zone on the lased root surface, and s.e.m. analysis revealed a characteristic microroughness on the lased surface. The laser scaling provided a level of calculus removal that was similar to that provided by the ultrasonic scaling. However, the Er:YAG laser produced superficial, structural and thermal microchanges on the root cementum. [source]

Effects of Ethanol on Extracellular Levels of Adenosine in the Basal Forebrain: An In Vivo Microdialysis Study in Freely Behaving Rats

ALCOHOLISM, Issue 5 2010
Rishi Sharma
Background:, Adenosine is implicated to play a pivotal role in mediating many neuronal responses to ethanol. While in vitro studies performed in cell culture have demonstrated that acute ethanol exposure increases extracellular adenosine levels, this effect has not been demonstrated, in vivo, in the brain. We performed an in vivo microdialysis study to examine the effects of local ethanol perfusion on extracellular levels of adenosine in the basal forebrain (BF). Methods:, Under sterile conditions and using a standard surgical protocol, adult male Sprague,Dawley rats were implanted with unilateral microdialysis guide cannula targeted toward the BF. Following postoperative recovery, the microdialysis probe was inserted. After allowing at least 12 to 16 hours for probe insertion recovery, the experiment was begun. Artificial cerebrospinal fluid (aCSF) was perfused (0.7 ,l/min) for 80 minutes, and 4 × 20-minute pre-ethanol baseline samples were collected. Subsequently, 30, 100, and 300 mM doses of ethanol were perfused. Each ethanol dose was perfused for 80 minutes, and 4 × 20-minute samples were collected. Finally, aCSF was perfused, and 4 × 20 postethanol samples were collected. Adenosine in the microdialysate was separated and measured with HPLC coupled with an UV detector. On completion, the animals were euthanized, brain removed and processed for histology. Results:, Local ethanol perfusion in the BF produced a significant increase in extracellular adenosine with the highest dose of 300 mM ethanol producing a 4-fold increase. Cresyl violet (Nissl) staining did not indicate any toxic damage in the area surrounding the probe tip. Choline acetyltransferase immunohistochemistry revealed that all microdialysis probe sites were localized in the BF. Conclusion:, Our study is the first to demonstrate that ethanol acts directly in the brain to increase extracellular adenosine. [source]

Polar phonon mode selection rules in tip-enhanced Raman scattering

JOURNAL OF RAMAN SPECTROSCOPY, Issue 10 2009
Samuel Berweger
Abstract We discuss the use of the symmetry selectivity of phonon Raman scattering to determine nanocrystallographic information of solids using tip-enhanced Raman scattering (TERS). The necessary degrees of freedom arise from the combination of the Raman selection rules reflecting crystal symmetry superimposed by the polarization and k -vector-dependent field enhancement and scattering of the scanning probe tip. The resulting phonon TERS selection rules are discussed, including the use of the crystal Raman tensor and momentum conservation for polar phonon modes. We demonstrate the selection rules for both far-field and tip-enhanced near-field Raman scattering from bulk and nanocrystalline LiNbO3. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Molecular dynamics simulation of the contact process in AFM surface observations

LUBRICATION SCIENCE, Issue 2 2002
J. Shimizu
Abstract In the present work, several molecular dynamics simulations have been performed to clarify dynamically the contact mechanism between the specimen surface and probe tip in surface observations by an atomic force microscope (SFM) or friction force microscope (FFM). In the simulation, a three-dimensional model is proposed where the specimen and the probe are assumed to consist of monocrystalline copper and rigid diamond or a carbon atom, respectively. The effect of the cantilever stiffness of the AFM/FFM is also taken into consideration. The surface observation process is simulated on a well-defined Cu{100} surface. From the simulation results it has been verified that the surface images and the two-dimensional atomic-scale stick-slip phenomenon, just as is the case for real AFM/FFM surface observations, can be detected from the spring force acting on the cantilever. From the evaluation of the behaviour of specimen surface atoms, the importance of the specimen stiffness in deciding the cantilever properties can also be understood. The influence of the probe tip shape on the force images is also evaluated. From the results it can be verified that the behaviour of the specimen surface atoms as well as the solid surface images in AFM/FFM surface observations can be understood using the molecular dynamics simulation of the model presented. [source]

New implementation of a SNOM suitable to study topographical features over wide areas

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2005
A. Ustione
Abstract A new implementation of a SNOM is described, aiming at the topographical study of large areas and exploiting the advantages of the shear-force detection system. This technique finds very interesting application in the study of archeological or artistic samples, where it often occurs that an area to be examined at high resolution (optically, topographically or chemically) is enclosed in a wider one. The implemented system allows to obtain scans of wide areas by using dc-motors to move the sample under the probe tip, and thus it can face rough samples with height differences of several tens of micrometers. It allows the user to choose whether to use the SNOM to study the optical and topographical properties of a small part of the sample (up to tens of square micrometers), or to use the motor-driven scan technique, to study the topographical characteristic of a large area of the sample (up to some square millimeters) and even over rough surfaces. We show results detecting worn relieves over a coin. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]