Core temperature measurement by microwave radiometry

A ‘double-container model’ was used for core temperature (T_c) measurement by microwave emission radiometry (MR) of warm fluid inside a tube, placed in a container with a cooler fluid. The intensity of microwaves emitted from the warmer fluid inside the tube were measured using a MR metering device, consisting of an antenna linked to a low-noise radio frequency amplifier (bandwidth 500 MHz, centered at 4.0 GHz). Based on the MR measurements, a T_c prediction model was developed for measuring the temperature of fluid inside a tube, achieving a sensitivity of ±0.5 °C at environmental temperature of 33–37 °C.     

A miniature integrated device for automated multistep genetic assays

A highly integrated monolithic device was developed that automatically carries out a complex series of molecular processes on multiple samples. The device is capable of extracting and concentrating nucleic acids from milliliter aqueous samples and performing microliter chemical amplification, serial enzymatic reactions, metering, mixing and nucleic acid hybridization. The device, which is smaller than a credit card, can manipulate over 10 reagents in more than 60 sequential operations and was tested for the detection of mutations in a 1.6 kb region of the HIV genome from serum samples containing as few as 500 copies of the RNA. The elements in this device are readily linked into complex, flexible and highly parallel analysis networks for high throughput sample preparation or, conversely, for low cost portable DNA analysis instruments in point-of-care medical diagnostics, environmental testing and defensive biological agent detection.     

CO2 angiography: development and trial of an animal experimental gas dosage device

Gas have long been used in radiological examinations, in particular for the diagnostic evaluation of gastrointestinal diseases. However, not until the introduction of digital subtraction angiography was carbon dioxide also used with success for angiography of arteries. In order to advice exact and reproducible dosage of the gas with freely selectable injection parameters, a carbon dioxide gas metering device was developed. The principle of gas metering is based on the measurement of the pressure gradient of the gas across a defined pneumatic resistance. The gas metering devices was tested in 15 animal experiments to produce survey and selective angiograms.     

Simple techniques for microclimate measurement

This paper describes simple ways of measuring the very local climate near the ground, and explains what these measurements mean. The equipment described includes a solar radiometer and a dew point instrument, both with mercury-in-glass thermometers, and a thermocouple psychrometer. The psychrometer may be used with standard metering equipment and a suitable metering device is described. Examples are given of field measurements taken with some of the equipment described and the presentation of results and their interpretation are discussed.     

Loss of blood at operation; a method for continuous measurement

A method for continuous measurement of surgical blood loss has been devised and has been used clinically in some 400 cases. The method combines volumetric measure of the suction loss and gravimetric measure of the sponge loss. The volumetric device automatically deducts the volume of rinse water used and thus measures the amount of blood collected in a metering cylinder. The suction loss scale shows continuously the amount of blood in the metering cylinder. The gravimetric device requires counting sponges into the weighing pan, and turning a dial scale to deduct the initial weight of the sponges. The volume of blood in the sponges is then read directly on the dial scale. Use of the instrument, which is under the supervision of the anesthesiologist, adds about two minutes per hour to the time normally required for counting the sponges; and about three minutes per hour is required for tending the volumetric instrument.In clinical use, knowing constantly the amount of blood loss permits the starting of transfusion before serious deficit develops, and then maintaining the patient's blood volume at a predetermined optimum level. In some 400 cases the continuous measurement of the blood loss served as a reliable guide for carrying out the loss-replacement plan within close limits of accuracy.     

LOSS OF BLOOD AT OPERATION—A Method for Continuous Measurement

A method for continuous measurement of surgical blood loss has been devised and has been used clinically in some 400 cases. The method combines volumetric measure of the suction loss and gravimetric measure of the sponge loss. The volumetric device automatically deducts the volume of rinse water used and thus measures the amount of blood collected in a metering cylinder. The suction loss scale shows continuously the amount of blood in the metering cylinder. The gravimetric device requires counting sponges into the weighing pan, and turning a dial scale to deduct the initial weight of the sponges. The volume of blood in the sponges is then read directly on the dial scale. Use of the instrument, which is under the supervision of the anesthesiologist, adds about two minutes per hour to the time normally required for counting the sponges; and about three minutes per hour is required for tending the volumetric instrument.In clinical use, knowing constantly the amount of blood loss permits the starting of transfusion before serious deficit develops, and then maintaining the patient''s blood volume at a predetermined optimum level. In some 400 cases the continuous measurement of the blood loss served as a reliable guide for carrying out the loss-replacement plan within close limits of accuracy.     

Non-chemical biofouling control in heat exchangers and seawater piping systems using acoustic pulses generated by an electrical discharge

Acoustic pulses generated by an electrical discharge (pulsed acoustics) were investigated as a means for biofouling control in two test formats, viz. a 5/8" outside diameter titanium tube and a mockup heat exchanger. The pulsed acoustic device, when operated at 17 kV, demonstrated 95% inhibition of microfouling over a 20 ft length of titanium tube over a 4-week period, comparable to chlorination in combination with a high-velocity flush. The pulsed acoustic device inhibited microfouling over a downstream distance of 15 ft, therefore, a single pulsed acoustic device is theoretically capable of protecting at least 30 ft of tube from microfouling (15 ft on either side of the device). A correlation between acoustic intensity in the frequency range 0.01-1 MHz and the level of biofouling inhibition was observed. The threshold acoustic intensity for microfouling inhibition was determined for this frequency range. It was also observed that the orientation of the device is critical to obtaining microfouling inhibition.     

Non-Chemical biofouling control in heat exchangers and seawater piping systems using acoustic pulses generated by an electrical discharge

Acoustic pulses generated by an electrical discharge (pulsed acoustics) were investigated as a means for biofouling control in two test formats, viz. a 5/8" outside diameter titanium tube and a mockup heat exchanger. The pulsed acoustic device, when operated at 17 kV, demonstrated 95% inhibition of microfouling over a 20 ft length of titanium tube over a 4-week period, comparable to chlorination in combination with a high-velocity flush. The pulsed acoustic device inhibited microfouling over a downstream distance of 15 ft, therefore, a single pulsed acoustic device is theoretically capable of protecting at least 30 ft of tube from microfouling (15 ft on either side of the device). A correlation between acoustic intensity in the frequency range 0.01-1 MHz and the level of biofouling inhibition was observed. The threshold acoustic intensity for microfouling inhibition was determined for this frequency range. It was also observed that the orientation of the device is critical to obtaining microfouling inhibition.     

THE USE OF THE ABBOTT-RAWSON TUBE

The Abbott-Rawson tube is a useful device in gastrointestinal surgery, as it obviates intravenous and intramuscular therapy. Jejunal rather than intravenous feedings may be used and the tube may also be used for administration of potassium, antibiotics and vitamins.     

CO2 angiography: measuring blood flow with injected gas bubbles]

The use of CO2 gas as a contrast medium for visualizing blood vessels has been considerably facilitated by the development of a gas metering device for mechanical injection of CO2. The present paper describes the possibility of using CO2 not only for visualizing blood vessel morphology, but also for the diagnostic evaluation of the haemodynamics within the vessels. For this reason in vitro experiments with an artery simulation model were undertaken to examine the behaviour of injected gas bubbles. The information thus obtained was then translated to animal experiments.     

Analytical model for managing hypotony after implantation surgery of a glaucoma drainage device

The main aim of glaucoma treatment is to reduce the intraocular pressure (IOP). One of the most common surgical treatments of glaucoma is the implantation of a glaucoma drainage device to drain the aqueous humor from the anterior chamber to a filtration bleb, where the aqueous humor is absorbed. In some cases, the excess of drainage causes ocular hypotony, which constitutes a sight-threatening complication. To prevent hypotony after this intervention, surgeons frequently introduce a suture into the device tube, which increases the hydraulic resistance of the tube and, therefore, the IOP. This study aims to provide an analytical model to correct hypotony following implantation surgery of a glaucoma drainage device, which may help glaucoma surgeons decide on hypotony treatment. The results indicate that the IOP after implanting a cylindrical tube around 300 μm in diameter is essentially the same as that built up in the filtering bleb and can hardly be controlled by introducing a straight suture unless the suture diameter is slightly lower than that of the tube. On the contrary, when the tube diameter is smaller than, for example, 100 μm, significant reductions of the IOP can be obtained by introducing a thin suture into the tube.

     

基于磁驱动技术的空肠营养管的设计

目的:为解决目前床旁鼻肠管快速置入成功率低这一临床难题,该文提出一种基于磁驱动技术的空肠营养管的设计。方法:分析了现有空肠营养管置管过程中的动力因素,结合磁驱动技术原理,提出了通过体外旋转磁场带动体内感应磁体螺旋式前进的设计方案,以期缩短空肠营养管的飘管时间。结果:该设计包括磁性空肠营养管和体外磁力驱动装置两部分。其中磁性空肠营养管由管体和感应磁头两部分构成,感应磁头包括磁体内核和硅胶外壳。磁力驱动装置由多极磁体和手持式微型电机组成。操作时通过体外磁力驱动装置发出大旋转磁场带动空肠营养管的感应磁头做轴向旋转运动,可加速空肠营养管在肠道内的移动,达到缩短飘管时间的目的。结论:该设计基于磁驱动技术原理,设计巧妙,符合磁力学原理,操作简单,具有临床应用潜力。     

Feasibility of the laryngeal tube airway for artificial ventilation in pigs and comparison with the laryngeal mask airway

Airway management in anesthetized pigs is known to be technically demanding, and the 'gold standard' technique of endotracheal intubation is particularly difficult to master. The authors investigated the feasibility of the laryngeal tube as an alternative technique for airway management in German Landrace pigs (n = 5). They compared this method with the laryngeal mask, which is considered to be an effective yet relatively straightforward tool for porcine airway management. One after the other, investigators attempted to establish an airway in each anesthetized, artificially ventilated pig using each device. The laryngeal tube was too short to intubate the largest pig (weighing 45 kg), and it took investigators slightly longer to insert this device compared with the laryngeal mask. With the laryngeal mask, there were several incidents of gastric insufflation. Despite these complications, all investigators were able to establish a secure airway and maintain oxygenation with the laryngeal tube, and all subjectively rated both devices as easy to use.     

A tube-cutting device for fractionating preparative gradients from the ultracentrifuge

A device is described which cuts off the bottom of a polyallomer (plastic) centrifuge tube, allowing collection of a preparative gradient from the bottom through a large-diameter opening. The gradient flows downward through a funnel-shaped portal positioned below the tube, and the cross-sectional area of flow is gradually restricted. This device resolved into separate peaks DNA sample components differing in density by only 0.007 g/ml in neutral cesium chloride.     

Airway management with the laryngeal tube in rabbits

The rabbit's oropharyngeal anatomy complicates the use of endotracheal intubation for airway management during surgical procedures. To determine if the laryngeal tube is useful for airway management in rabbits, the authors applied the device and evaluated its efficacy to ventilate the lungs. The laryngeal tube was inserted blindly and without difficulty in six healthy male New Zealand White rabbits; all of the rabbits were ventilated adequately with and without neuromuscular blockade. The authors conclude that the laryngeal tube can be used as an alternative means of airway management in rabbits.     

Cell-free protein synthesis in microfluidic array devices

We report the development of a microfluidic array device for continuous-exchange, cell-free protein synthesis. The advantages of protein expression in the microfluidic array include (1) the potential to achieve high-throughput protein expression, matching the throughput of gene discovery; (2) more than 2 orders of magnitude reduction in reagent consumption, decreasing the cost of protein synthesis; and (3) the possibility to integrate with detection for rapid protein analysis, eliminating the need to harvest proteins. The device consists of an array of units, and each unit can be used for production of an individual protein. The unit comprises a tray chamber for in vitro protein expression and a well chamber as a nutrient reservoir. The tray is nested in the well, and they are separated by a dialysis membrane and connected through a microfluidic connection that provides a means to supply nutrients and remove the reaction byproducts. The device is demonstrated by synthesis of green fluorescent protein, chloramphenicol acetyl-transferase, and luciferase. Protein expression in the device lasts 5-10 times longer and the production yield is 13-22 times higher than in a microcentrifuge tube. In addition, we studied the effects of the operation temperature and hydrostatic flow on the protein production yield.     

Development of micro-shock wave assisted dry particle and fluid jet delivery system

Small quantity of energetic material coated on the inner wall of a polymer tube is proposed as a new method to generate micro-shock waves in the laboratory. These micro-shock waves have been harnessed to develop a novel method of delivering dry particle and liquid jet into the target. We have generated micro-shock waves with the help of reactive explosive compound [high melting explosive (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) and traces of aluminium] coated polymer tube, utilising ??9?J of energy. The detonation process is initiated electrically from one end of the tube, while the micro-shock wave followed by the products of detonation escape from the open end of the polymer tube. The energy available at the open end of the polymer tube is used to accelerate tungsten micro-particles coated on the other side of the diaphragm or force a liquid jet out of a small cavity filled with the liquid. The micro-particles deposited on a thin metal diaphragm (typically 100-??m thick) were accelerated to high velocity using micro-shock waves to penetrate the target. Tungsten particles of 0.7???m diameter have been successfully delivered into agarose gel targets of various strengths (0.6?C1.0?%). The device has been tested by delivering micro-particles into potato tuber and Arachis hypogaea Linnaeus (ground nut) stem tissue. Along similar lines, liquid jets of diameter ??200?C250???m (methylene blue, water and oils) have been successfully delivered into agarose gel targets of various strengths. Successful vaccination against murine salmonellosis was demonstrated as a biological application of this device. The penetration depths achieved in the experimental targets are very encouraging to develop a future device for biological and biomedical applications.     

Elastic plastic tube for detecting exfoliative cancer cells in the esophagus.

A simple device for sampling esophageal lesions is described. The instrument, which is easy and inexpensive to make, consists of a single-lumen plastic tube covered with cotton thread. Once swallowed, the end of the tube can be drawn into a loop. The device has been used at locations with a high incidence of esophageal cancer and at our tumor hospital. A series of 746 cases examined had no complications. The tube has a positive diagnostic rate comparable to that of roentgenography, 96%, and seemed acceptable to both physicians and patients. When an obstruction is present, the instrument can easily pass through it and obtain exfoliated cancer cells, while the conventional method, the balloon cytologic smear, is unable to do so.     

SwizzleStick: A novel positive displacement microliter diluting device

The SwizzleStick, a simple positive displacement device for dispensing a microliter volume of sample from a microhematocrit capillary tube, is described. Because it is essentially a diluting device, a dye dilution test using both aqueous and protein-containing solutions of sodium sulfobromophthalein was devised to test the accuracy and precision of the SwizzleStick. The mean of the absorbances of 10 replicate 1 in 201 SwizzleStick dilutions, made by dispensing 20 μl of aqueous dye solution into 4.0 ml of buffer dispensed with a certified grade A volumetric pipet, was 0.216, SD 0.0005, CV 0.24% while the mean of the absorbances of 10 readings of a single bulk 1 in 201 dilution made with certified grade A glassware (1.0-ml volumetric pipet, 200-ml volumetric flask) was 0.216, SD 0.0004, CV 0.19%. Repeat studies using dye solution containing 6% human albumin showed that the volume dispensed by the SwizzleStick is not affected by the viscosity of plasma.     

A new isoelectric focusing gel for two-dimensional electrophoresis constructed in microporous hollow fiber membranes

We describe the preparation of IEF tube gels inside a nonwetting microporous plastic tubing. The gel in the tube need not be extruded after the first dimension separation. Instead, the porous structure of the tubes is made wettable, and the proteins are electrophoresed "through-the-wall" into the second dimension PAGE gel. Commercial ampholytes and reagents are suitable for the procedure. A useful p/ range of 4.5-9.5 can be obtained when p/ 3-10 ampholyte mixtures are used. Because of the high surface area of the porous material, precautions must be exercised to reduce oxygen inhibition during polymerization and dehydration of the gel during storage and use. A sheath device is described that satisfies these requirements. The plastic tubes can be disposed of by incineration and pose no biohazard.