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The use of the diaphragm and spermicide as an intravaginal barrier-method of contraception was investigated at the West German family-planning center of the Arbeiterwohlfahrt. The follow-up study was based upon the application of a semistandardized method of learning how to handle the diaphragm and spermicide by step-by-step instructions for 158 women and investigated their early and later experiences by questionnaires in two follow-ups after a mean observation period of 2 years and 4 months.

Publisher Summary This chapter discusses the sample introduction systems. The total peak broadening of a solute, introduced in a certain volume at the top of the column as visualized by the detector, is built up of contributions from each separate part of the system. The variance of the elution curve, on a volume or time basis, is equal to the sum of the separate variances of each part because they are independent of each other. The parts that might contribute significantly, a part from the column itself, are the injection system, connection tubes plus terminators and detector. This type of sample introduction can be subdivided into two classes: (i) septum-type syringe injectors and (ii) septumless syringe injectors. With septum-type, the sample is injected on to the top of the column through a self-sealing rubber membrane (septum) by means o f a syringe. Septum-type injection is the easiest and cheapest method of sample introduction. Septumless syringe injectors have been developed in order to avoid the disadvantages of the self-sealing rubber membranes but keeping the advantages of syringe injection.

The disc oxygenator has been provided with an automatic blood level control permitting only a maximal variation of ±2 mm. Through a rubber membrane in the bottom of the outlet portion of the disc oxygenator the weight of the blood column is transmitted to scale connected with an electronic regulation of the voltage to the pump motor. The heat exchanger is built in into the oxygenator by using a double-walled trough of stainless steel. The aim of this investigation has been to make the disc oxygenator easier and safer to operate and to diminish priming by including the heat exchanger.Visual inspection of the oxygenator blood level in order to balance arterial pump rate with venous return has proved to be an easy, simple and safe method in the hands of an experienced pump operator. However, continuous attention is needed. Good perfusions have been obtained in the first 500 cases with an ordinary disc oxygenator. The extra safety factor with an automatic flow control becomes more important for the more frequ...

Rosenbloom and Gies1 have shown that many ether soluble substances diffuse from ether through rubber membrane into ether, but oddly various phospholipins do not possess this property.Together with Boas,2 I was able to show that various cholesterolesters diffuse from ether through rubber membrane into ether. This is very interesting on account of the high molecular weight of these esters. Cholesterol-stearate with a molecular weight of 652.51 diffuses very readily.For some time I have been trying to find an ether soluble substance of higher molecular weight than cholesterol-stearate and which could be easily detected in the diffusate. The free dye-acid of iodoeosin fulfilled these requirements. This free dye-acid has been employed by Professor Ehrlich as a very delicate reagent for free alkali in the erythrocytes of man.3Iodo-eosin is the potassium salt of tetraiodo-fluorescei'n with the following formula,As a salt it dissolves in dilute alkalies with red color, but is insoluble in ether or any other organ...

While investigating the influence of the viscosity of the blood on the output of the heart, I observed that the cardiac discharge depends in a large measure on the temperature of the fluid used to vary the viscosity. This observation prompted me to disregard secondary effects for the present and to determine, first of all, the relationship between the temperature of the blood and the cardiac output. The output of the heart was ascertained in accordance with the method of Rothberger. 1 The heart was placed in an oncometer of glass, the changes in the volume of the heart being recorded by air transmission. Rothberger confined his measurements to the changes in the ventricles, the volumetric variations of which were obtained by covering the large orifice of the oncometer with a rubber membrane and by inserting the organ up to its auriculoventricular junction through a central opening in the

It has been reported that global warming has invoked an ever increasing typhoon intensity as well as a long-term rise in sea levels which jointly cause severe coastal wave overtopping. A simple measure to cope with this undesirable change is to simply increase the crest height of coastal structures. This measure is certainly effective in the prevention of wave overtopping, but it can also reduce coastal visibility and lead to the degradation of waterfront seascapes. In this paper, Deformable Rubber Membrane Parapets (DRMP), which not only suppress the wave overtopping in storm periods, but also can retain coastal seascapes in milder conditions, are presented. With numerical analyses using a nonlinear finite element program and hydraulic experiments, the air controlled expansion and contraction of the parapets are investigated, together with their structural behaviors and stability against wave overtopping.

Objective: Our goal was to design an inexpensive amniocentesis trainer for instruction and practice with ultrasonography-assisted needle guidance and the freehand technique. Study Design: The amniocentesis trainer was constructed from a commercially available 5.3-L storage box (No. 5805; Rubbermaid Incorporated, Wooster, Ohio). Sonodense sperical targets 2.3 cm in diameter were taped to the bottom, and the box was filled with a gelatin mixture. The box was covered with a rubber membrane from a pelviscopy trainer (United States Surgical Corp, Norwalk, Conn). After the gelatin mixture set overnight at 40°F, the amniocentesis trainer was ready for use. Results: When a needle is introduced through the membrane into the gelatin, the ultrasonographic image is a reasonable simulation of an amniocentesis. The trainer improved the ability of an operator to perform a freehand amniocentesis, orient the ultrasound transducer, follow a needle with continuous ultrasonographic guidance, and hit a 2-cm target. The gelatin also allows for evaluation of improvement between amniocentesis attempts because a faint image of the needle track from prior attempts remains visible. Once basic amniocentesis skills are mastered, the trainer is easily modifiable so that obstacles can be added that could simulate umbilical cord and fetal extremities. Conclusions: We were able to construct an inexpensive amniocentesis trainer that facilitates instruction in the freehand amniocentesis technique. This trainer enables an operator to master the skills necessary to perform the technique of freehand ultrasonography-guided amniocentesis under direct ultrasonographic visualization without putting a patient through the discomfort of participating in the learning curve. (Am J Obstet Gynecol 1998;179:1225-7.)

Some further results and points are presented to underline the theory of constant horizontal tension of the rubber membrane as discussed in a previous paper by the author.(3) Small deflexion theory which assumes constant resultant tension fails, in the case of coaxial geometry, to account at large deflexions for (a) the linear force-deflexion law obtained and (b) the close correspondence of the membrane's contour to Laplace's equation. Both observations are successfully predicted by the revised theory which places no limitations on geometry or deflexion for the above two conditions to hold. Experiment also confirmed a linear force-deflexion law for an asymmetric geometry.

Use of the rubber membrane model as a teaching aid is discussed, both for elementary lecture demonstrations and for intermediate laboratory experiments. The model can be used to demonstrate directly and vividly by analogy two-dimensional potential fields, and trajectories of particles moving in these fields.

A large-capacity water balloon aparatus has been developed specifically for measuring the in-situ density of compacted high-way trench backfill. In operation water is expelled from a calibrated 6-L reservoir to displace a rubber membrane. A dual-valve system enables larger volumes to be measured by repeated filling of the reservoir. The apparatus is simple, robust, and inexpensive, and has been used to measure hole volumes up to 30 L, with depths up to 0.8 m. It is much smaller and more easily handled that previous medium capacity apparatuses. Proving trials have shown that the apparatus can reliably determine hole volumes to an accuracy of +0/−0.6%, which is a significant improvement over the performance of the standard small volume equipment.

To verify the expressions developed by other researchers for separating the strength component resulting from volume change in shear (dilatancy), shear tests at constant volume as well as drained tests are necessary. In conventional undrained triaxila tests on granular mateials, volume change of the soil skeleton occurs as a result of rubber membrane penetration. In the present investigation, conventional tests were modified to ensure a constant volume condition by compensating for the rubber membrane penetration. Drained tests, conventional undrained tests, and modified undrained tests were conducted on a uniform medium sand, uniform coarse sand, and a gap-graded sand; the results are compared. Conventional undrained tests gave somewhat higher values of shear strength than those of modified undrained tests. The results of drained tests corrected for volume change compare well with those of modified undrained tests. /Author/

MOST of us are familiar with the lecture-table experiment known as the Cartesian Diver. A variation of this is shown in Fig. 1a. In this apparatus the diver is replaced by a test-tube T floating upside down in the water, being buoyed up by just the right quantity of air, A. The tall jar is nearly filled with water, and then capped by a rubber membrane tied on tightly. When the membrane is pressed in, the pressure of the air just below it is communicated through the water to the air, A, within the test-tube (thus illustrating Pascal's principle). This lessens the volume of the air, and thus its buoyant force (thus illustrating Archimedes' principle), and consequently the test-tube sinks. The tube may therefore be caused to float or sink or remain stationary in the water by suitable pressure on the rubber membrane.