Current status of the development of wireless sensors for medical applications]

Wireless near-field transmission has been a challenge for scientists developing medical sensors for a long time. Here, instruments which measure a patient's ECG, oxygen saturation, blood pressure, peak flow, weight, blood glucose etc. are to be equipped with suitable transmission technology. Application scenarios for these sensors can be found in all medical areas where cable connections are irritating for the doctor, patient and other care personnel. This problem is especially common in sport medicine, sleep medicine, emergency medicine and intensive care. Based on its beneficial properties with regard to power consumption, range, data security and network capability, the worldwide standard radio technology Bluetooth was selected to transmit measurements. Since digital data is sent to a receiving station via Bluetooth, the measurement pre-processing now takes place in the patient sensor itself, instead of being processed by the monitor. In this article, a Bluetooth ECG, Bluetooth pulse oximeter, Bluetooth peak flow meter and Bluetooth event recorder will be introduced. On the one hand, systems can be realized with these devices, which allow patients to be monitored online (ECG, pulse oximeter). These devices can also be integrated in disease management programs (peak flow meter) and can be used to monitor high-risk patients in their home environment (event recorder).     

Mechanical device for morphological and orientation analysis of biological structures

A simple mechanical device for different kinds of morphological analysis is suggested. It consists of a binocular microscope, a luminiscent illuminator, a coordination table with a disc-chuck (0-360 degrees) and a nest for disposing the test systems and the light or electronmicroscopic negatives (6 x 9 and 9 x 12). The analysis is performed by means of visual scanning of the negatives, by counting the number of crossings of the structure with the test system knots and by registration of the measurements by a key recorder. For orientation analysis the microscope is supplied with a goniometer (0-360 degrees) and an oculometer with a cross of filaments.     

A battery-operated, flow-through thermistor thermometer

A battery-operated self-balancing thermistor temperature indicator is described, producing a D.C. voltage output, 1 V or less, to a recorder or moving coil meter.     

The isolation amplifier, an interface between EEG recorder and data processor

An isolation amplifier is presented which is intended as an interface between electrophysiological recorders and standard data processing equipment. Due to its floating input and output, differences in ground potentials do not disturb the transmitted signal. Hence, recorder and data processors can be grounded according to the manufacturer's recommendation. Powerline leakage currents are also prevented from loading the ground of the electrophysiological recorder. Compared to the isolation transformer this device saves space, while polarity restorations can be made and no modifications are needed in any piece of equipment.     

A portable miniature solid-state heart rate recorder for monitoring daily physical activity

A compact, rugged, solid-state heart rate recorder (63 X 94 X 22 mm, 195 g) to measure normal daily heart rates over periods of up to 33 h is described. With an interval switch a selection can be a mean heart rate over 30, 60 or 120 sec. The ECG amplifier filter is equipped with an automatic gain control to eliminate R-wave amplitude changes during physical activity. A continuous acoustic check on correct electrode attachment and sufficient signal amplitude is possible by means of an earphone. Data may be stored on punch tape, tape recorder, or processed on-line, or plotted directly one a line writer to obtain a heart rate profile over the measured time. In 45 studies with adults and children the heart rate recorder has proven to be a reliable instrument.     

A pH-metrical method of determining glucose-6-phosphatase activity

A simple, rapid, and reproducible method of determining glucose-6-phosphatase activity is described. The glucose 6-phosphate hydrolysis is accompanied by the disappearance of the protons from the medium owing to a phosphate species pK change from 6.1 (in glucose 6-phosphate) to 6.9 (in inorganic phosphate). Alkalization is registered by a pH meter with a recorder. The method described in this paper may be used in routine determinations of glucose-6-phosphatase activity.     

Tapping to a Slow Tempo in the Presence of Simple and Complex Meters Reveals Experience-Specific Biases for Processing Music

Musical meters vary considerably across cultures, yet relatively little is known about how culture-specific experience influences metrical processing. In Experiment 1, we compared American and Indian listeners'' synchronous tapping to slow sequences. Inter-tone intervals contained silence or to-be-ignored rhythms that were designed to induce a simple meter (familiar to Americans and Indians) or a complex meter (familiar only to Indians). A subset of trials contained an abrupt switch from one rhythm to another to assess the disruptive effects of contradicting the initially implied meter. In the unfilled condition, both groups tapped earlier than the target and showed large tap-tone asynchronies (measured in relative phase). When inter-tone intervals were filled with simple-meter rhythms, American listeners tapped later than targets, but their asynchronies were smaller and declined more rapidly. Likewise, asynchronies rose sharply following a switch away from simple-meter but not from complex-meter rhythm. By contrast, Indian listeners performed similarly across all rhythm types, with asynchronies rapidly declining over the course of complex- and simple-meter trials. For these listeners, a switch from either simple or complex meter increased asynchronies. Experiment 2 tested American listeners but doubled the duration of the synchronization phase prior to (and after) the switch. Here, compared with simple meters, complex-meter rhythms elicited larger asynchronies that declined at a slower rate, however, asynchronies increased after the switch for all conditions. Our results provide evidence that ease of meter processing depends to a great extent on the amount of experience with specific meters.     

An Illuminator for Ultramicrotome Knife Orientation and Block Approach

The construction and operation of a simple, inexpensive illuminator that produces high quality illumination of the ultramicrotome knife edge and the edge to block face gap resembling dark field is described. Use of the illuminator greatly speeds knife adjustment and reduces the likelihood of specimen or knife edge damage. The illuminator uses a grain-of-wheat light bulb and an adjustable bulb holder fashioned from bent paper clips. The holder permits both lateral and axial adjustment of the bulb position, which is necessary to achieve satisfactory illumination with different specimens and knives. The illuminator, with slight modification, can be adapted for use on any ultramicrotome.     

北京地区五种常见鸣虫的鸣声结构

本文对寒蝉、蚱蝉、鸣鸣蝉、锐声鸣螽和大扁头蟋五种鸣虫雄虫的鸣声结构进行了较系统的研究。这些昆虫鸣声节律以及声谱和声压的瞬时变化均有显著的不同。一种昆虫的鸣声频谱范围虽然很大,但不同频率的图象却都和主频率的图象一样。     

Gas Flow Measurement in Fermentations: An Inexpensive System with Analogue Output for Recording

During the fermentation of North Sea Gas to single cell protein in a gas-recycle system (Spivey 1973) there was a need to measure continuously low gas flow rates and to obtain a recorder signal proportional to the instantaneous flow rate. Commercial equipment, such as differential pressure transmitters linked to a pneumatic recorder, was expensive and not readily modified for the low flow rates of laboratory fermentations.     

Flow-Throuk Density Meter for Zonal Centripugation and Other Procedures

The instrument is based on the principle that the transmission of beta-particles through a fluid is a function of density. The fluid flows through a 3mm diameter cylindrical channel in a perspex block and passes between a 1 milliCurie 90_Sr/ 90_Y ceramic bead point source and a plastic phosphor optically coupled to a photomultiplier. The signal is amplified and displayed on a countrate meter coupled to a paper chart recorder, Facilities for zero suppression and scale expansion of the countrate meter reading are provided. The instrument whioh was designed originally for zonal centrifugaticn, has been used to monitor sucrose (ρ 1.0–1.3) and caesium chloride (ρ 1.0–1.8) solutions at flow rates up to 50ml/min. The accuracy attained is normally better than ± 0.1% of density at any point in the range. The instrument has also been used with success to monitor gradients in isoelectric focusing (personal communication from K. B. Cooke of the Westminster Hospital Medical School). 1. R. S. Atherton, P. Hawtin and P. Hutchinson, Anal Biochem., 49, 326 (1972)     

The neurokinin A receptor activates calcium and cAMP responses through distinct conformational states.

G protein-coupled receptors are thought to mediate agonist-evoked signal transduction by interconverting between discrete conformational states endowed with different pharmacological and functional properties. In order to address the question of multiple receptor states, we monitored rapid kinetics of fluorescent neurokinin A (NKA) binding to tachykinin NK2 receptors, in parallel with intracellular calcium, using rapid mixing equipment connected to real time fluorescence detection. Cyclic AMP accumulation responses were also monitored. The naturally truncated version of neurokinin A (NKA-(4-10)) binds to the receptor with a single rapid phase and evokes only calcium responses. In contrast, full-length NKA binding exhibits both a rapid phase that correlates with calcium responses and a slow phase that correlates with cAMP accumulation. Furthermore, activators (phorbol esters and forskolin) and inhibitors (Ro 31-8220 and H89) of protein kinase C or A, respectively, exhibit differential effects on NKA binding and associated responses; activated protein kinase C facilitates a switch between calcium and cAMP responses, whereas activation of protein kinase A diminishes cAMP responses. NK2 receptors thus adopt multiple activatable, active, and desensitized conformations with low, intermediate, or high affinities and with distinct signaling specificities.     

A fiber optic biosensor (FOBS) to monitor mutans streptococci in human saliva

A fiber optic biosensor (FOBS) to monitor mutans streptococci activity in human saliva is developed. The biosensor utilizes e fiber optic evanescent wave spectroscopy to monitor a bacterial mediated biochemical reaction. To achieve this, a short length of the cladding is removed; the fiber core surface is treated and coated with a thin film of porous glass medium using sol-gel technique. The mutans streptococci mediated reaction with sucrose is monitored using a photosensitive indicator, which is immobilized within the porous glass coating. Spectroscopic analysis shows that the transmitted intensity at 597 nm increases conspicuously when monitored for 120 min. Two distinct phases are observed, one from 0 to 60 min and the other from 60 to 120 min. A negative correlation coefficient between the rate of increase in absorption peak intensity recorded by the FOBS and the decrease in pH measured using the pH meter, was calculated to be rho=-0.994. This investigation highlights the potential benefits of this sensor to monitor mutans streptococci activity in saliva.     

A simple device for spot counting in photomicrographs or electron micrographs.

A simple apparatus for spot counting in photomicrographs or electron micrographs is described, consisting of an illuminator on which the photographic print in placed and a counting pen. By making small holes in the photograph with the specially designed spring-loaded counting pen, the spot counted can be clearly located by the light from the illuminator falling through the hole, whereas a microswitch built into the counting pen makes an electronic counting system to move one digit.     

An automatic respirometer for determining oxygen uptake in crayfish (Austropotamobius pallipes (Lereboullet)) over periods of 3-4 days.

1. An automatic respirometer has been developed for continuous measurements over 3-4 days on 1-15 g crayfish. The sensor is a modified Mackereth oxygen electrode. Respiration is recorded on a millivolt potentiometric pen recorder during closed periods when the O2 concentration in the medium falls to a predetermined level. A solenoid-operated valve is then opened via a relay circuit energized by a reed switch mounted on the recorder. Medium flows through the respirometer until the O2 concentration is raised back to another predetermined level. Artificial media containing little or no nutrient salts are used to restrict the growth of microbes. 2. Respiration was determined chiefly on crayfish (Austropotamobius pallipes) with body wet weights of 7-0-12-5 g at 10-0 degrees C. In unrestrained but relatively quiescent animals, standard metabolism is described by the regression equation, ln O2 uptake = 3-3037 + 1-002 ln body wt. In restless crayfish active metabolism is described by the equation, ln O2 uptake = 4-4412 + 0-861 ln body wt.     

A simple light-level recording device to monitor lighting in animal quarters

The performance of lighting timers in animal rooms was tested with a portable light-level recorder. The instrument monitored the light and dark phases under various degrees of illumination. This inexpensive method of electronic surveillance ensured the validity of experiments dependent on photoperiodicity.     

Environmental,health, and safety risks of the power lines nearby the human settlements

Advances in technology have not always been in favor of human beings and can lead to the emergence of “emerging contaminants” in human dwellings. These contaminants have taken a new form that is colorless, tasteless, and odorless and invisibly pollute the environment. Due to being intangible, their control and measurement are more difficult than the other types of pollutants. This study is an attempt to identify and assess the risks induced by high-voltage power lines crossing a residential area in southern Iran. To this end, the process of power transmission and the equipment used was initially identified. Afterward, the failure modes of the equipment resulting in the occurrence of risk were detected. In order to measure the strength of the magnetic field, the 3D EMF TESTER was used. The identified risks were scored based on the Environmental failure mode and effects analysis (EFMEA) parameters and a risk priority number (RPN) was assigned to each risk. In the final step, SPSS version 16 software was applied to calculate the risk level and identify the top priority risks. The highest RPN values obtained were related to the health risks so that all identified risks in this group were subjected to an emergency situation. The highest RPN was 360 assigned to “cable (no privacy)” and “power transmission line (non-compliance with privacy standards)”, while the lowest RPN was 60 subjected to disconnect switch (disconnector). Since majority of the identified risks has a high RPN, some mitigating measures were proposed to reduce the risk intensities as much as possible.     

Light Transmission and Preference of Eye Patches for Occlusion Treatment

Purpose

To investigate light transmission and preference for six eye patches for occlusion therapy.

Methods

Six patches were examined, including; Ortopad Fun Pack, Ortopad Flesh, Kawamoto A-1, Kawamoto A-2, 3M Opticlude, and Everade Eye Guard. The size and the presence of a light blocking pad of patches were investigated. The amount of light transmitted through the patches was evaluated, using a digital light meter and a model eye, in three different environments; indoors with fluorescent light, outdoors on a sunny day, and strong light from illuminator. After patching the normal eye, the flash visual evoked potential (VEP) was measured. Thirty patients with amblyopia or horizontal strabismus, who received occlusion therapy as initial treatment, were included. After using all six patches, patients completed a 7-item questionnaire regarding the patch preference for size, color and shape, adhesive power, pain with removal, skin irritation after removing patch, parent’s preference and overall opinion.

Results

All patches had a light-blocking pad, except the 3M Nexcare. Ortopad had the strongest light blocking power in the three environments, and the 3M Nexcare had the weakest power. In flash VEP, Ortopad and Kawamoto patches showed flat, but 3M Nexcare and Everade Eye Guard showed normal response. There were significant preferential differences among the patches in all the items of the questionnaire (P<0.05). In comparison between the patches respectively, 3M Nexcare received the lowest satisfaction in pain when removing a patch and skin irritation after removing a patch. Kawamoto A-2 received the lowest score in the overall satisfaction.

Conclusions

We found differences in the light-blocking power and in the preference of the various patches for the occlusion treatment. This is a pilot study regarding only characteristics and preferences of patches. Further clinical studies regarding the relationship between characteristics or preferences of patches and outcomes of occlusion treatment are needed.     

The bacteriophage phi 29 head-tail connector shows 13-fold symmetry in both hexagonally packed arrays and as single particles.

The symmetry of the phi 29 head-tail connector is controversial: several studies of two-dimensional arrays of the connector have found a 12-fold symmetry, while a recent study of isolated particles has found a 13-fold symmetry. To investigate whether a polymorphism of the structure might explain these different results, electron microscopy and image analysis were used to study both isolated connectors and particles in hexagonally packed arrays. The hexagonally packed arrays have a P1 symmetry, and the connectors displayed 13 subunits both in the arrays and as isolated single particles. While we do not observe a polymorphism between connectors in two-dimensional arrays and as isolated particles, data show that the connectors can exist with either 12 or 13 subunits. A three-dimensional reconstruction of our 13-fold connector was generated by combining an averaged side-view projection with the known symmetry. The structure of rosettes of the connectors formed in the presence of phi 29 prohead RNA (pRNA) was also examined. These rosettes contain five connectors arranged about a single connector in the center, and this arrangement may reflect an essential role of the pRNA in mediating a symmetry mismatch between either a 12- or 13-fold symmetric connector and a putative fivefold symmetric prohead portal vertex into which the connector fits.     

Open LED Illuminator: A Simple and Inexpensive LED Illuminator for Fast Multicolor Particle Tracking in Neurons

Dual-color live cell fluorescence microscopy of fast intracellular trafficking processes, such as axonal transport, requires rapid switching of illumination channels. Typical broad-spectrum sources necessitate the use of mechanical filter switching, which introduces delays between acquisition of different fluorescence channels, impeding the interpretation and quantification of highly dynamic processes. Light Emitting Diodes (LEDs), however, allow modulation of excitation light in microseconds. Here we provide a step-by-step protocol to enable any scientist to build a research-grade LED illuminator for live cell microscopy, even without prior experience with electronics or optics. We quantify and compare components, discuss our design considerations, and demonstrate the performance of our LED illuminator by imaging axonal transport of herpes virus particles with high temporal resolution.