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PURPOSE: To report nonarteric anterior ischemic optic neuropathy (NAION) as an ocular manifestation in a woman with combined primary antiphospholipid syndrome and Factor V Leiden (FVL) mutation. METHODS: Case report of a middle-aged woman with hematological investigations confirming the diagnosis of both primary antiphospholipid syndrome and Factor V Leiden mutation, who presented with visual disturbance in her left eye. RESULTS: NAION was noted in her left eye. The patient was promptly treated with low molecular weight heparin, followed by warfarin, which resulted in the reversal of the ischemic optic neuropathy. CONCLUSIONS: Primary antiphospholipid syndrome and coexisting Factor V Leiden mutation should be considered in the differential diagnosis of NAION. Prompt treatment with anticoagulants can result in the reversal of the ischemic process.

Air sampling and surveillance cultures for fungi were performed in a Scottish general haematology ward over a five-month period in 1997. The mean total fungal count from the air sampling appeared to be correlated with the number of patients colonized by Aspergillus. The most commonly isolated species were Aspergillus versicolor, A. fumigatus and A. niger. Rooms with portable air filtration units had significantly lower total fungal counts than the others. Swabs were taken from 70 patients (mean age 62 years); 114 of the 563 cultures (20.2%) were positive. The most commonly isolated species were A. fumigatus, Candida albicans, C. glabrata and C. parapsilosis. Samples taken from the tongue and perineum showed colonization more often than those taken from the nostrils. Almost half the patients (48.6%) were colonized on, or within seven days of, admission; 11.4% became colonized whilst on the unit. One patient developed fatal aspergillosis. We conclude that colonization or high air-borne spore concentrations are not necessarily predictive of fungal infection but may prompt early treatment or more aggressive prophylaxis of potentially fatal invasive infections.

Post-transfusion purpura (PTP) was diagnosed in a female patient 1 week after transfusion for hysterectomy. Despite treatment with oral steroids and intravenous immunoglobulin, platelet counts remained low, and the patient developed profuse rectal bleeding. Random platelet transfusion is reported to be ineffective in PTP. We report a case in which the transfusion of HPA-la negative platelets provided good increment and clinical haemostasis before intravenous immunoglobulin could have had an effect.

Viral-associated haemophagocyte syndrome in response to infection with human parvovirus B19 was seen in 2 patients with hereditary spherocytosis. Depressed reticulocyte response during acute parvovirus infection is a known cause of hypoproliferative crises in patients with reduced erythrocyte lifespan; the observation of parvovirus-associated haemophagocytosis could account for the pancytopenia that may accompany human parvovirus B19 infection.

Euonyminol [octahydro-2,5 a-bis(hydroxy methyl)-2,9-dimethyl-2H-3,9a-methano1-benzoxepin-4,5,6,7,8,9,10-heptol] is an alkaline hydrolysis product of the alkaloids isolated from Tripterygium wilfordii Hook (Celastraceae). In the parent alkaloids the polyhydroxy nucleus has eight esterified hydroxyl groups, one free hydroxyl group and an O atom involved in a cyclic ether linkage. Euonyminol crystallizes in the monoclinic space group C2 with cell dimensions a = 16.323 (7), b = 8.314 (7), c = 11.809 (5) A and fl -96.7 (1) °. Data were collected on an automatic diffractometer and the structure was solved by direct methods. The 25atom model was refined to an R index of 0.056. The structure consists of two trans-fused six-membered rings and a five-membered cyclic ether formed by fusion of two axial substituents. Euonyminol is related to the polyhydroxy nuclei of other Celastraceae alkaloids such as maytoline and evonine, and a best molecular fit program has been used to compare the structures.

A problem of leakage was encountered in hydraulic actuators because of wear in the rod-gland bearing which consisted of a chromium plated steel rod and a silver plated steel gland. To improve the actuator life, the gland was changed to 440C stainless steel and the rod was plasma arc coated with WC-Co. This combination of materials gave a marked improvement in the wear resistance under long stroke cycling but created a new problem associated with rapid short stroke cycling. Fretting induced by the rapid short stroke cycling caused the cobalt-rich phase of the rod coating to cold weld to the gland. Then fatigue failures in the WC-Co coating allowed metal transfer in the bearing and subsequent scoring of the rod. An economical remedy was found in a woven Teflon-fiber liner bonded to the bearing surface of the gland.

In the course of radio research carried out at McGill University few years ago, the author had occasion to employ a variety of matrix devices in transmission-line and impedance calculations. Since these are not available in a connected exposition, it has been suggested that useful purpose would be served by bringing them together so as make them readily accessible in connected form. The methods are applicable, not merely to the principal wave on a two-conductor transmission line, but also to all plane-wave processes, in wave guides in space, which are amenable to representation by means of transmission lines. Furthermore, matrices of higher orders can be used the same way to deal with problems of multiple transmission. The use matrices in this connection is not new; 1, 2, 3 the object of the present paper is to specialize both methods and notation for practical purposes the basis of experience in using them. The paper also includes some new results. In particular, attention directed to formulae by which the input impedance may be calculated for a large number of loosely-coupled loads such as occur when long array is fed from a transmission line or wave guide (Section 9). Secondly, the simple conceptions of series- and shunt-loading are generalized in Section 8 in a manner appropriate to the loading waves; in this connection, it is unnecessary to use equivalent circuits, which sometimes hinder rather than assist effective representation. All of the methods indicated here have been found to be useful practice: they should therefore recommend themselves to electrical engineers and physicists.

Equivalent networks were determined for a right angle transition between a coaxial line and a shielded helix. By employing a movable mercury short on the helix it was possible to determine these equivalent circuits through the use of well-known microwave measurement techniques. Utilizing the possible physical connection which might exist between the junction and its equivalent circuit, an attempt was made to measure quantitatively the effect of varying various parameters in the junction. For the limited number of cases studied, no simple connection between the elements of the equivalent circuit and the physical parameters of the junction was discovered. Although the results for the equivalent networks were very sensitive to small experimental errors, by using these networks it was possible to calculate reasonably accurate values of input impedence in the coaxial line for known impedance terminations on the helix.

(1928). CXIX. Fluorescent secondary X-radiation and the J-phenomenon. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 5, No. 33, pp. 1145-1163.

The results of probe measurements along a shielded helix terminated in a plane conducting "short" are given. These results seem to indicate that the higher-order fields at the short are reactive and that the minimums are shifted out from the normal 180-degree position. The amount of this shift seemed to be relatively constant at approximately 38 degrees from 500 to 2,000 megacycles for a particular helix. A very approximate analysis of the helix short is made where the helix and its image wire are considered as a tapered two-wire transmission line. The position of the first minimum is determined by a numerical integration using the transmission line equations. This analysis predicts the correct direction of the shift of the minimum and also gives a rough idea as to the amount of this shift over the given band of frequencies.

This paper discusses design considerations and performance characteristics of a 5 MW peak, 300 kW average power L-band klystron. The tube to be discussed is a 4 cavity klystron tunable over a 10% frequency range centered at 1320 Mc. Nominal operating parameters are a beam voltage of 135 kv and a beam current of 120 amp. The rf pulse length is 40 microseconds, the rf duty factor .06. The tube utilizes a non-intercepting modulating anode which permits the application of sophisticated beam modulation techniques. The crucial design problems on this program can be classified into 3 major areas. They are: the generation, focusing and collection of an electron beam with an average power in excess of 1 MW; the transmission of 300 kW of average rf power through an output window and the beam modulation by a non-intercepting control electrode. The very large beam power required extreme care in the design of the beam forming and beam focusing. Beam powers up to 1.3 MW of average power are focused through a drift tube with 1 1/8 inches I. D. The interception without rf drive is below 1%. The design of a collector capable of dissipating this amount of power with surface collection densities low enough and water cooling surface large enough for reliable long life operation was a major problem which had to be solved. The power handling capacity of the output window was a limiting factor in achieving higher output powers. Because of the comparatively low peak power of this tube the window problem was an average power problem only. Thermal stresses caused by excessive and non-uniform heating of the window are the limiting factor. Excess heating of the window due to single surface multipactoring has been eliminated and with proper heat transfer design the heat generated by unavailable rf losses in the window material can be handled easily. The final window design has been tested up to a power level of 380 kW without failing. The third problem of switching a modulating anode with a gain of one at voltages up to 140 kv has also been successfully solved on this tube. A special design of the modulating anode area completely eliminated the so-called post pulse arcing phenomena which so far has been a limiting factor in using modulating anodes at these high voltages.

We have developed a method of increasing the concentration of He3 in He3–He4 mixtures by "superfluid filtration", relying upon the fact that liquid He4 flows rapidly through a small leak while the He3 in solution remains behind. In this way an increase in concentration from 2% to 95% can be achieved in a single operation. The rate of processing is about 200 standard cc. of the initial gaseous mixture per hour.

A new approach incorporating the use of low Q ceramic loaded center cavities has been used to obtain bandwidths of the order of 10% in L-band. The loaded cavities are tuned to resonant frequencies which, when compensated by the response of a low Q input cavity, give an optimally bunched beam over a frequency bandwidth of more than 100 Mc. The design employed here differs from the conventional stagger-tuned klystron design in that the low Q's of the center cavities enable them to be tuned out of the frequency band of interest with the result that the phase shift characteristics of the tube is flatter than when the cavities are stagger-tuned within the band.