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Experimental procedures for evaluating the column compression properties of graphite/epoxy laminated composites are described. The test procedure allows the determination of a buckling curve up to and including the inelastic, fully supported, zero-length column. Verification of the test procedure is provided by using flat aluminum test specimens. Application to specific graphite/epoxy laminated composites is described. Inelastic compression properties are shown to be highly sensitive to environmental conditions and laminate lay-up. Prediction of the elastic compression properties of graphite/epoxy laminates by the Euler relation is shown to be significantly nonconservative.

• The postphlebitic syndrome is a common affliction with limited therapeutic options. Patients who fail to respond to treatment with graded elastic compression stockings often develop a chronic pain syndrome manifested by intractable pain and swelling. Because lymphedema, a condition also associated with leg pain and swelling, has been successfully treated by intermittent compressive therapy with an extremity pump, we conducted a pilot study of compressive therapy in patients with severe postphlebitic syndrome. All five patients studied had dramatic improvement in symptoms and functional status without side effects. Although a large randomized trial is needed to properly evaluate compressive therapy, it appears to be very effective in selected patients. ( Arch Intern Med. 1989;149:1651-1652)

Graded elastic compression stockings on the lower leg were evaluated for their ability to (1) decrease leg volume, (2) decrease circumference, and (3) alleviate discomfort. One hundred three test subjects participated in this study, including 30 normal, asymptomatic control subjects. The conditions of the 73 symptomatic patients were categorized by pain and swelling, varicose veins, venous stasis, lymphedema, and phlebitis, which constituted symptoms in 120 legs. Although total body weight did not change during the week of observation, the volume, circumference, and pain decreased in the symptomatic group. The volume of the stockinged leg decreased in comparison with the nonstockinged control leg in the asymptomatic subjects as well. We conclude that non-custom-made graded elastic stockings with 24 mm Hg of pressure at the ankle are effective in decreasing volume, circumference, and symptoms in the lower leg in patients with minimal problems during a one-week period. ( JAMA 1983;249:242-243)

To the Editor .—In your editorial, "News on Thromboembolism from London" (Arch Surg 109:477, 1974), you called attention to an article by Browse et al (Br J Surg 61:219, 1974) that alleges that elastic stockings are ineffective in preventing thrombi in calves of patients undergoing major surgery. Before such a conclusion can be accepted, it is important to consider how this compression affects venous blood flow velocity. Elastic compression in that study was provided by a single layer of tubular stockinette (Tubigrip), size G4RT 6.75 cm, applied from the ankle to below the knee. No evidence was presented that this increased linear flow velocity in deep veins. Browse et al cite an article by Makin et al. 1 However, Makin et al used a double layer of Tubigrip and measured venous circulation time, not linear velocity per se. Furthermore, there are features of single-layer Tubigrip that indicate that it may

The invention relates to devices using transducer elements comprising a film of piezoelectric polymer arranged between electrodes. The transducer element in accordance with the present invention is in the form of a thermoformed protuberance. These devices are used for detecting and generating elastic compression waves, for infrared radiation, and for storing electrical energy.

The ability of graduated compression elastic stockings to prevent hypotension during elective epidural caesarean section was evaluated. Twenty women were randomly assigned to two groups of ten, one group being fitted with the stockings. The incidence and degree of hypotension were the same in both groups. Graduated compression elastic stockings are of no benefit in reducing the incidence of maternal hypotension during caesarean section.

Venous disease is ten times more common than peripheral arterial disease, but when compared to the excitement generated by recent advances in the management of arterial diseases, the subject of venous disease usually makes physicians either bored or bewildered. Both emotional reactions seem inappropriate after reading this book. For the bewildered, the author starts with basics. He approaches chronic venous insufficiency, for instance, by first labelling it an "incurable hydraulic abnormality." Because elastic compression will control the faulty hydraulics, 88% of venous ulcers can thereby be cured without surgery. The important point is that the patients must wear elastic support for life, just as those with optical abnormalities must wear glasses for life. Equally basic, stasis in the soleal venous plexus, the "main peripheral venous heart," is still the most common source of pulmonary emboli. In testifying to the force exerted by the soleal venous pump, the author offers a

To determine whether elastic compression alters the venous hemodynamics in the postphlebitic limb, we measured venous pressure patterns in 11 postphlebitic limbs with and without elastic compression stockings. Following cannulation of a dorsal vein of the foot, the patients underwent measurements of basal resting pressure, maximum percent decrease in venous pressure with exercise (ΔVPex), peak systolic venous pressure during exercise (SVPmax), the amplitude of the pressure swing, and venous return time. Elastic compression did not alter basal resting pressure, ΔVPex, or venous return time. By contrast, SVPmaxdecreased from 139±0.3 mm Hg to 111±8 mm Hg with elastic compression. If venous ulcers are related to the high pressure developed in the superficial veins during calf muscle systole, then elastic compression may be beneficial by decreasing systolic venous pressure and its subsequent deleterious consequences. (JAMA242:2766-2768, 1979)

• We studied 80 patients who were older than 50 years of age to determine if graded elastic compression stockings reduced the frequency of postoperative thrombosis in patients undergoing dextran 70 prophylaxis. All of the patients received a total of 2,000 mL of dextran 70 during three days; according to a random table, each of the patients had one leg encased in a graded compression stocking for one week. Thrombosis development was screened with the fibrinogen I 125 test. Eight patients manifested thrombosis—one in the thigh and seven in the calf—localized to the unstockinged leg, a frequency significantly greater than the zero frequency in the stockinged leg. No untoward effects of this combination prophylaxis were noted. ( Arch Surg 1984;119:1329-1331)

The crustal shear pattern proves the existence of a rigid, elastic crust of considerable strength in which distortional forces of importance must have occurred. As no handy terms exists for these distortional geotectonic forces, the writer proposes to use the expression “regmagenic forces.” Such forces can be created in the crust by a polar drift of the crust over the core, by great fluctuations of the elastic compression in the presence of sensible elastic anisotropics or by unequal tangential stresses (orogenic forces). The writer agrees with Vening Meincsz that polar drifts played a part in the making of the regmatic shear pattern of the crust. He does not think however that this was the only cause and attributes great importance to the other two mentioned reactions. The writer does not believe in the existence of subcrustal currents sufficient to create crustal tectonics and rejects also the idea of such currents in source of a polar drifting. Even if they existed, their total drift moment on the whole crust would be inadequate to overcome the strong elastic counterforces within the crust. Polar drifts can be explained in harmony with the mechanical principles admitting the presence of a sensible general elastic compression and additional regmagenic forces in the tangential plane of the crust. This mechanical, deduction and the proved polar displacements of the past point out that an Earth contraction stands behind the tectonical unrest. A revision of this old concept on the ground of modern knowledge seems highly promising. The origin of the continents is discussed under such an assumption as well as the regmatic pattern of the Earth's crust. The continents are explained as the scars of the past tectonic surface reductions. Some related problems are discussed, especially the significance of the drowned islands of tho Pacific lately described by Hess [see “References” at end of discussion, 1940] as metering cones of tho progressing contraction of the Earth of the past.

Blood flow velocity was measured in the femoral veins of ten inactive recumbent subjects in order to determine the effect of elastic stocking compression on venous flow. A noninvasive Doppler ultrasound technique was used to measure blood flow velocity. Results of these studies indicate that elastic stockings increase femoral venous flow velocity during periods of compression up to three hours. This increase in blood flow velocity persists for up to 30 minutes after removal of stockings. Compression reduces the fluctuation effect of respirations on venous flow, resulting in a more constant flow. These findings indicate that elastic compression of the lower extremities produces effects (increased venous flow velocity and decreased venous pooling) that may reduce the occurrence of venous thrombosis.

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