Sensor Holder Research Articles

Assessment of pulp blood flow in primary and permanent teeth using pulse oximetry

Pulse oximetry (PO) is a well-accepted non-invasive method for assessing vascular health, based on oxygen saturation (SaO(2) ) measurements. The objectives of this study were to design and build a custom-made PO dental sensor holder, to evaluate the effectiveness of PO in determining pulp blood flow in primary and permanent teeth, and to compare the SaO(2) levels obtained in teeth and on the little finger of patients. The PO sensor adapted to the custom-made sensor holder is termed as a device to position and hold the PO sensor. This study evaluated SaO(2) readings obtained in the pulp of 123 teeth of 84 children aged 4-13years. The teeth were divided into three groups: group I - primary teeth: 23 central incisors and 28 canines; group II - permanent teeth: 25 central incisors and 28 canines; and group III - endodontically treated teeth (control): 12 permanent central incisors and seven primary central incisors. The pulp blood flow and SaO(2) were measured and were compared with readings of the patient's finger. Data were analyzed by paired t-tests and Pearson's analysis method. The PO was able to identify all the clinically normal pulps contained in the sample, and all the endodontically treated teeth (controls) showed no response. The mean SaO(2) values were 85.27% in the teeth and 92.85% in the fingers. In conclusion, PO readings were effective in determining pulp blood flow in primary and permanent teeth. However, there was no correlation between the SaO(2) values in the fingers and in the teeth of the patients (P<0.05).

Development of the Precision Stage with Nanometer Accuracy and a Millimeter Dynamic Range

Most of the nano-positioning systems(stage) are accomplished by a flexure hinge mechanism, which is two or three multilayer PZT actuators to realize the high accuracy and long range[1]. In this paper, it can be made by a new nano stage with the bending characteristics of the mechanical cantilever that is composed of the step motor, one multilayer PZT actuator and the displacement sensor unit. The sensor unit consists of semiconductor LD, PD and sensor holder. The displacement of stage is acquired by the bending control of the cantilever between the step motor and the PZT actuator. The basic properties of the positioning stage are presented. From these results, we can know that the new nano stage can be made by only one multilayer PZT actuator .

Sulfamethazine detection with direct-binding optical waveguide lightmode spectroscopy-based immunosensor

A direct-binding optical waveguide lightmode spectroscopy-based immunosensor detecting sulfamethazine (SMZ) was prepared, followed by the measurement of its specificity and sensitivity. System construction was undertaken with a peristaltic pump, an injector and the main unit comprising a sensor holder, two signal-harvesting photodiodes, a beam mirror, shutter and He–Ne laser source emitting a monochrome light (λ=632.8nm), plus a PC. Antibody immobilization was performed in situ by covalent binding of an anti-SMZ antibody over the surface of a glutaraldehyde-activated 3-aminopropyltriethoxysilane-treated sensor chip. The reaction buffer for the system was 4mM Tris–HCl (pH 7.2) that showed a medium surface coverage and stable baseline. Sensor response was quite specific to antibody–antigen complexation, as judged from no sensor response caused by bovine serum albumin immobilization. The sensor responses according to SMZ concentrations from 10−8 to 10−2M increased linearly in a semi-logarithmic scale, with the limit of detection of 10−8M. The immunosensor was favorably reusable for SMZ screening.

滋気センサを用いた連続記録可能な上下的下顎位測定装置の開発

The purpose of this study was to develop a new device to measure continuously the vertical dimension of the human jaw relation using magnetic sensors. A sensor unit was made of six MI (Magneto-Impedance) sensors (AMI302 4.0 x 3.5 x 1.4 mm, Aichi Steel Corp.) placed in a line at intervals of 4 mm. The unit was positioned to the head by a glasses-type sensor holder. A target magnet (3 mm in diameter, 12 mm in length) was set in a resin board positioned on the mentum with adhesive tape. 1) In vitro experiments using a precision-movement stage were conducted. 2) One healthy volunteer (age: 25 years) was instructed to perform a jaw opening-closing task with 10 mm range of motion. Before and after the task his jaw position in the intercuspal position was measured for five minutes. The jaw movements were recorded simultaneously using a 6-degree-of-freedom jaw-tracking device. The mean square error of the in vitro experiment was 0.06 mm under the worst conditions. The mean square error of the positional accuracy was 0.35 mm. The reproducibility of the intercuspal position was 0.33 mm. These values correspond to about 16% of the value of the shift phenomenon of the resting position (approximately 2.2 mm). Our new device using an MI sensor enables the vertical dimension to be recorded continuously with sufficient accuracy.

Development of Novel Optical Fiber AE Sensor with Multi-Sensing Function

A novel optical fiber acoustic emission (AE) system with multi-sensing function in single long fiber was developed and utilized for the estimation of AE sources of model steel plate and jointed pipes. Multi-sensing function was achieved by dividing the single sensing fiber into several sensor portions with different resonance frequencies. The resonance frequencies were provided by winding the sensing fiber around the solid rods (sensor holders) with different diameters. The monitoring system with three sensors in a 10 m long fiber was demonstrated to detect three wave packets with different frequencies and correctly estimate the source locations of AEs from artificial (Nelson-Sue) sources on a 0.9 wide x 1.8 m long steel plate. Here the arrival times of AEs for the source location were determined by the continuous wavelet transform. Source locations on the steel plate were determined within a distance error of 53 mm. The system also makes the location of the pipe with damage possible.

Assessment of the efficacy of an indigeniously developed pulse oximeter dental sensor holder for pulp vitality testing.

Current routine methods of assessment of pulp vitality rely on stimulation of nerve fibres and give no direct indication of blood flow within the pulp. Pulse oximeter is a proven, atraumatic method of measuring vascular status, by evaluating oxygen saturation. This study explores the use of customized dental pulse oximeter sensor holder to assess pulpal vascular oxygen saturation in permanent teeth. Pulse oximeter readily differentiated between known vital and nonvital teeth. Vital teeth consistently provided oxygen saturation values that were lower than the values recorded on the patient's fingers. Pulse oximeter is an accurate, atraumatic clinical alternative to the present electrical and thermal methods of assessing pulp vitality in teeth.

In-Process Modelling and Estimation of Thermally Induced Errors of a Machine Tool During Cutting

A compact measurement system was developed to measure the time variant machine tool errors during cutting. The system is composed of a gauge, a sensor holder, 5 gap-sensors and a PC. The gauge is made of invar which has a very low thermal expansion coefficient, and is often used to measure the thermally induced errors of a machine tool. A new neural network model was considered to estimate the time variant machine tool errors during cutting using a new concept of input values. The detail of the model proposed is described in the paper together with experimental methodologies using a compact measurement system to examine the validity of this approach. These schemes were implemented on a small vertical-machining centre.

Endoscopic Urease Sensor System for Detecting Helicobacter pylori on Gastric Wall Using a pH‐sensitive Field Effect Transistor

Abstract:An endoscopic tube‐tip type urease sensor was developed for the purpose of on‐site detection of Helicobacter pylori (H. pylori) using a pH‐sensitive field effect transistor (pH‐FET). The sensor is composed of an endoscopic‐tube connected to a feed pump with a urea solution and a pH‐FET attached to a sensor holder at the open end of the tube. The urease activity on the gastric wall can be measured by bringing the sensor into contact with the gastric wall just after replacing gastric juice with the urea solution. The presence of H. pylori causes a pH change in the urea solution inside the sensor holder in 20 seconds due to the strong urease activity of this bacterial species. After measurement, the sensor is detached from the wall, and washed with urea solution by turning on the urea pump. A measurement at one site is completed within 30 seconds. Repetition of the procedure makes multi‐site measurements possible. In preliminary evaluations, it was found that clinical sensitivity and specificity were 89% and 86%, respectively, using standard bacteriological testing results as a reference.

Characteristics of heated sensors emitting by radiation only

The design of an oven-mounted sensor using a single mount is presented. The sensor is placed in vacuum inside a can. The sensor temperature is maintained constant by means of the heat directly furnished inside the can, the sensor holder being used as a heater. The sensitive part of the sensor is stressless and insensitive to temperature variations of the surrounding medium. Thermal losses occur by radiative transfers. A theoretical analysis of the thermal exchanges is given, pointing out that the thermal losses depend on a parameter α which varies only according to the geometry of the device and to the radiative properties of the materials used; moreover, the thermal losses are a function of the sensor and can temperatures. The role of each parameter is evaluated and the emissivity factor of the sensor area is shown to be the main factor ruling the thermal losses. The temperature distribution along the length l of the sensor is calculated, as well as the thermal-gain magnitude of the system. The variation of the standard sensor temperature versus the standard x/l coordinate is obtained. The slope at the origin does not depend on the material properties, and the average value of the sensor temperature is reached for x/l near 0.4. The thermal gain of the device reaches 500 or more for current thermal materials. Using a thermal screen interposed between the sensor and the can, the thermal gain is enlarged by several orders of magnitude. Numerical applications are applied to the case of piezoelectric accelerometers. Thermal gains greater than 10 6 are achieved, and a drastic reduction of energy consumption occurs relative to the case of classical ovens.

Piezoelectric bridge sound pick-up for string instruments

A piezoelectric bridge sound pick-up string instruments has a separate subassembly for each string. Each subassembly has a metal base body (4) with a pocket (4.1) for a piezoelectric sensor element (7), a sensor holder (5) and a pressure piece (8). The pocket is at right angles to the string and is tilted in accordance with the string pressure direction. The sensor element is embedded in an electrically insulating holder, which has a break in its central area (6) and allows a certain deflection of the sensor element. To an electrode on the under surface of the sensor element is fitted a conductor (9) for passing out a signal with positive potential. On an opposite, upper electrode surface is provided a pressure piece with a semi-circular cross-section, which transfers by friction the alternating pressure of the string (14) and functions as an electrical connection of ground potential.

Seismomagnetic effect generated by the October, 1989, ML, 7.1 Loma Prieta, California, Earthquake

A differentially connected array of proton magnetometers operated within the epicentral region of the October 18, 1989, ML 7.1 Loma Prieta earthquake for 12 years from 1974 to 1986. The closest magnetometer station was located 7.3 km from the epicenter of the earthquake and within 3 km of the site where anomalous ULF magnetic noise measurements were observed. Following the earthquake, the magnetometers were reinstalled with sensors replaced in the original undisturbed sensor holders. Comparison of pre‐1986 total intensity magnetic field data with data obtained during the months following the earthquake indicate local offsets of about 1 nT may have been generated at stations nearest the epicenter. Tests on other continuous differenced data from 1983 to present indicate that offsets determined could be biased by as much as 0.7 nT. The offsets can be approximately fit with a simple seismomagnetic model of the earthquake for which 1.9 m of right lateral and 1.3 m of dip slip (southwest side up) occurred on a fault patch between 6 km and 18 km deep and 45 km long. The total rock magnetization is assumed to be 1.5 A/m. Since the offset has persisted following the earthquake, an alternate explanation in terms of electokinetic effects is unlikely even though transient ground water flow occurred following the earthquake. Comparison of pre‐1986 and similar post‐seismic total magnetic field noise does not indicate any change caused by aliasing of ULF (0.01 Hz‐10 Hz) magnetic noise in the vicinity of the Loma Prieta earthquake.

Urban Psychology and Spirituality

One area in which the relationship between psychology and theology finds practical expression is that of Christian spirituality. A little-explored but promising branch of psychology for such study is that of environmental psychology. This article examines the ability of models of the human based on urban psychology to support the demands of the Christian life. The models so utilized are those of the human being as territorial animal, passive sensor, and preference holder. The implications of such models for Christian spirituality are explored, and in turn, these models are evaluated in terms of the commitment warranted by the Christian life, particularly by the practice of compassion.