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Variations in insecticidal effectiveness of aldrin and dieldrin in two different soils led to investigation of the persistence and possible transformation under field conditions. After 21 months, nearly one-half of the 5.4 p.p.m. of aldrin originally applied was lost, although a significant amount was recovered as dieldrin. Dieldrin loss from dieldrin-treated plots was less than aldrin Joss from aldrin-treated plots, and no significant transformation to aldrin was detected. Microbial activity appeared to be unimportant in these changes. Aldrin and dieldrin recoveries did not appear to correlate with buffer capacity, ammonium-binding power, cation exchange capacity, mechanical analysis, moisture tension, pH or chemical analyses of the soils. No single soil property appeared responsible for variations in effectiveness of the two insecticides. Properties found sufficiently different in the two soils to indicate that they may be concerned with this problem were their cation exchange capacities and their calcium and magnesium contents. The phenylazide method used on extracts of 20-gram soil samples was sensitive to 0.2 p.p.m. of aldrin and 0.4 p.p.m. of dieldrin. The method for extraction of aldrin needs additional investigation, Successive extractions with the usual aldrin solvent, Skellysolve B, gave higher recovery than single extraction. The dieldrin solvent, Skellysolve B plus 25% acetone, gave greater recovery of aldrin from soil with a single extraction. It appears that none of the methods used in these and in previous studies gave a complete picture of what happens to aldrin and dieldrin after their contact with the soil.

Gel'fand and Šilov(1) have introduced the concept of compatibility of norms on a vector space, defining two norms to be compatible if each sequence which is Cauchy with respect to both norms and converges to zero with respect to one norm, also converges to zero with respect to the other. They have found it convenient to build up their exposition of spaces of generalized functions (2) by developing the theory of locally convex spaces whose topology can be defined by a countable set of pairwise compatible norms. The author (3) has examined the properties of locally convex spaces which have been topologized by making a set of linear mappings into locally convex spaces continuous, and has shown that if this method is applied to a set of closed operators on Hilbert space, then the resulting spaces have topologies generated by a set of pairwise compatible norms. The purpose of this paper is to generalize this result by putting it in its natural context as a theorem on uniformities which have been defined by making a closed set of mappings uniformly continuous. The closed mappings of the title are mappings with closed graph.

Recent work on the absorption of microwave radiation in the frequency range 109 c/s to 3 × 1010 c/s is reviewed, with particular reference to materials of biological interest. The relative importance of ionic conduction, dipolar relaxation, particularly of water molecules, and resonance is discussed briefly. Conventional methods for dielectric constant and loss measurements at microwave frequencies can be adapted for use with biological materials and a number of such modifications is described. The results of investigations into the dielectric properties of water, the most abundant biological material, proteins and a variety of body tissues are outlined and discussed in terms of established dielectric theory. High power microwave generators have been used to study tissue heating, the heating pattern comparing favourably with predictions from the radiation propagation constants and the thermal properties of the materials. A few experiments on the effects of microwaves on animal tumours and on viruses are described.

The reaction between trivalent chromium and disodium cyclohexane diamino tetra acetate (CDTA) at the boiling temperature has proved to be a suitable one for the spectrophotometric determination of small amounts of CrIII covering the range 10–120 ppm in purely aqueous solutions. The variation of absorbancy with concentration conforms satisfactorily with Beer's law throughout the whole range. A variety of cations and anions do not interfere with such a determination. A procedure is given for the spectrophotometric titration of CrIII with CDTA.

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Simple modifications of standard X-ray apparatus are described for carrying out short distance “contact” therapy. For work requiring somewhat higher penetrations, a number of “middle distance” small field applicators for use on standard 200 kV therapy tubes are described. Radiation output, quality and depth dose measurements on the beams so produced have been made. Modifications of the “middle distance” applicators for intra-buccal treatments are described.

Very numerous critical potential determinations of atoms have been made, but there is a distinct lack of such data regarding molecules. The work to be described is a contribution to remedying this deficiency for nitrogen. It will be useful here to state the kind of molecular processes which our apparatus will recognize. There is first of all molecular excitation and ionization—as in the case of the ato —complicated, however, in excitation by the fact that there is not only the possibility of a change of electronic energy, but also of vibrational and rotational energies. In these experiments the resolving power of the apparatus is only adequate in the recognition of electronic and vibrational energy changes. So that only excitations from the lowest vibrational level of the normal electronic state to vibrational levels of higher electronic states will, in this paper, be considered.

Methods of protecting healthy tissues from irradiation by β and γ rays during surface radium treatment have been investigated physically by means of a thin-walled ionisation chamber. Special attention was paid to the possible influence of secondary β radiation from the filter material. The protective powers of wax, lead, and copper have been examined, and it is concluded that for most purposes lead is the most satisfactory material, its high γ-ray absorption more than compensating for its comparatively large β-ray emission. A thin layer of copper over the lead filtration appreciable reduces the surface ionisation, but this may have little or no effect on the skin reactions owing to the low penetrating power of the secondary β rays.

It is inevitable in a rapidly developing field such as Radiotherapy, depending, as it does, directly on the basic sciences, that the fundamental concepts of the subject should be kept under constant review. This is expressed in the periodic revisions of the Recommendations of the International Commission on Radiological Units. In 1953 the Commission completely revised and redrafted the Recommendations which had been in use, with only minor changes, since 1937. The least extensive, but by far the most fundamental changes have been made in Section A of the Recommendations, which deals with physical units of dose. In 1950 the suggestion that specific energy absorption in an irradiated material should eventually become the basis of dosage was first put forward formally. No unit, other than the classical erg per gramme, was indicated. In 1953 the Commission went a step further and defined the rad as the unit of absorbed dose, distinct from the rontgen as the unit of dose: “Absorbed dose of any ionizing radiati...

Previous investigations of high voltage X rays have been extended to a detailed consideration of the output of an X-ray tube up to 370 K.V. A number of typical output curves are given. The theories of the intensity distribution in the continuous X-ray spectrum leading to the formula I = KV2 for the energy output of a tube are briefly discussed. The values of the index of V in this formula are obtained from experimental results, and the effects of filtration are observed. It was found to be impossible to fit the results to the usual form of the formula I = KVp over the whole range of voltages used. Using unfiltered radiation the value of the index appeared to fall below the theoretical value of 2. It is suggested that this may be due to the breakdown of the ionisation method of measuring the energy output for soft radiations. I should like here to express my gratitude to my colleague, Dr. W. V. Mayneord, for much valuable discussion and criticism of this work; and to Professor J. M. Woodburn Morison, in wh...

Special studies were made with two different soils when aldrin, dieldrin and heptachlor (5 p.p.m.) were mixed with regular and autoclave soils with and without the addition of urea at 5 p.p.m. The rate of decline of aldrin, dieldrin and heptachlor was measured by total chlorine and bioassay methods. In addition, decline of aldrin and dieldrin was measured by the specific phenylazide method. In genera], the total chloride and bioassay methods showed a high initial recovery of the insecticides from the soil, followed by a rapid decline. The specific phenylazide method showed little insecticide change after 11 months. The decline of insecticides could not be associated with soil microorganisms or with the physical and chemical properties of the soil.

It is of great importance, for scientific reasons and for the more limited purpose of safeguarding against possible dangers in X-ray therapy, to discover whether there may be conditions which facilitate the production of tumours by X -rays. Some light has already been thrown on this problem. Lacassagne and Vinzent (1929) (1933) caused inflammation in the groins of rabbits by the subcutaneous injection of Streptococcus caviae . The lesions in some of these rabbits were submitted to X-radiation, the dose in each instance being about 600 r. Such doses had a beneficial effect on the infective lesions, but sarcomas developed in five of the twelve survivors at the sites of irradiation. In a later experiment non-infected inflammatory lesions, produced in rabbits by the subcutaneous injection of sterile diatomaceous earth, were exposed to X-rays, the dose being 600 r. as before. Two of these rabbits, at the end of 22 and 34 months respectively, were dead with malignant tumours at the site of irradiation (Lacassagne 1933). Similar doses of X-rays given to rabbits in the absence of inflammatory lesions did not induce tumour formation (Lacassagne 1936). Since a total of 600 r. is well within the limit of dosage used for therapeutic purposes in man, it seemed desirable to carry out further experiments of this nature. Experimental Technique Non-infective foci of inflammation were caused in twelve young adult rabbits as follows: 3 c. c. of olive oil containing 10% of finely powdered silica were injected subcutaneously in the right groins. Four days later, as no distinct swellings were present, the injections were repeated, 2% of oleic acid having been added to the olive oil. On the following day 7 c. c. of a suspension of kaolin (10% in water) were injected into the same sites. Three days later obvious swellings were present. Each rabbit was anaesthetized with “Evipan” and the swollen tissues were exposed to a single dose of 600 r., the rest of the rabbit being protected by a shield of lead. The conditions of irradiation were— 250 kV, 4 mA, filter 0·5 mm. Cu, time approximately 23 min.

The rheogoniometer is an instrument for the analysis in space and time of the complete stress distribution in a viscoelastic liquid subjected to a known shearing action. A greatly improved form of the instrument is described which affords increased accuracy, electronic measurement of the various components of stress for rapid recording, and a more elaborate drive. This incorporates in a single instrument the alternative actions of unidirectional laminar shear, oscillatory laminar shear, a superposition of these two, and a predetermined acceleration to or deceleration from the first type. With this drive, an independent vibrational analysis of the mechanical properties of the material in its “rest” state or in any steady state of shear can be made.

Once the initial density, D1, is noted, a single piece of freshly isolated mammalian tissue is analyzed for water and fat. Knowing the densities of water and fat, the tissue's fat-free density, D2, and the dry, fat-free density, D3, can be computed. Among the various types of soft tissues, since D3 is similar, a simple relationship is shown to exist between the fat-free water content and the corresponding density. The biological extremes in a water:fat:protein system thus operate in such a way that the quantity of fat can be predicted from an equation containing three variables, i.e. the initial weight and density of a tissue and its quantity of water. This is of interest in human body composition and also to those who desire to make a sequence of determinations on a single piece of tissue without having to submit a portion thereof to direct analysis of fat, e.g. to express tissue electrolytes and water content on the fat-free basis. Submitted on June 15, 1959

Rabbit plasma albumin was labelled with I131, injected intravenously, and measurements were made of the radioactivity in plasma, urine, and feces over many days. In some experiments plasma radioactivity was fractionated into I131-albumin activity and that of labelled breakdown products. Curves of these radioactivities were compared with corresponding curves predicted by four mathematical models. Each model included a vascular and extravascular albumin compartment in transfer equilibrium, a radioactive breakdown products compartment, and an excretion compartment; but model A supposed I131-albumin catabolism to occur within the vascular system, model B within the extravascular compartment, model C within both, and model D within a separate compartment receiving albumin for catabolism from the plasma. The experimental data were reasonably well predicted by models A and C. However, model D, though data were insufficient for its complete validation, gave the best predictions and agrees with present knowledge of albumin catabolism. Various methods for calculating the rate of albumin breakdown are discussed. When calculations are based solely on the plasma radioactivity data, identical rates are predicted by models A, C, and D. When, as a valuable independent method, catabolism is calculated from plasma and excreted radioactivities, an error (ordinarily small) is incurred unless account is taken of the rate of passage of I131-albumin to the breakdown sites, and of the rate of excretion of the radioactive breakdown products.

New measurements of the absorption of filtered gamma-rays from radium (B + C) in aluminium, carbon and lead have been made. A small condenser type of ionization chamber has been used, which overcomes many of the difficulties usually inherent in this kind of measurement. Detailed consideration has been given to the corrections which must be applied to ionization measurements before absorption coefficients can be calculated. From the most recent theories of absolution by scattering, photoelectric effect, and electron pair formation, total absorption coefficients for lead over the wave-length range concerned have been calculated. The problem of the effective wave-length of a filtered heterogeneous gamma-ray beam is discussed in some detail, and a proposed method of estimation put forward. Comparison of the calculations of µ / ρ with the experimental figures indicates that the photoelectric absorption rises more rapidly with increasing wave-length than is predicted by theory.

The main methods of defining the “quality” of an X-ray beam are discussed and criticised. It is concluded that the simple half-value method is, at the moment, least open to criticism. Spectra of high voltage radiations through Pb, Sn and Cu show the superiority of Sn as a filter. This is demonstrated in many ionisation experiments. Combinations of metals are discussed and suggestions made for practical filters. The question of the most suitable metal for h.v.l. measurements is raised, and it is suggested that tin is the most suitable material.

A number of physical problems which arise in the use of radium surface applicators of small area are considered from the point of view of radium and radiation distribution. Depth dose curves show the advantages of the use of larger radium skin distances, the improvement being particularly marked at the edge of the applicator. The effects of errors in radium distribution and radium skin distance are indicated. With a view to overcoming some of the difficulties, specifications of a number of standard small applicators are given.

Steaks from mechanically pressed tenderloins and steaks from paired, unpressed control tenderloins from Good and Choice grade steers were studied. Pressing did not adversely affect overall quality of the tenderloin steaks; however, fibers of the pressed steaks were kinked and compacted when compared to control steaks. No differences in fiber breakage or in sarcomere length were noted. Fat, moisture, lean color, marbling texture, marbling amount, lean texture, lean firmness and moisture on the steak surface were similar in pressed and unpressed steaks, Panel scores for tenderness, juiciness and flavor and Warner-Bratzler shear values were also similar for pressed and unpressed steaks. Pressed steaks had greater cooking loss, but they were more uniform in size and shape than control steaks.

The effects of steak location, storage time and precooking internal temperature upon steak quality were evaluated. Steaks from the anterior ends of the tenderloins were darker in color and displayed greater surface moisture than steaks from the posterior ends. Fresh-processed tenderloin steaks displayed more surface moisture than steaks from tenderloins stored 6 or 12 months. Warner-Bratzler shear values increased with storage. Steaks which were broiled starting at 1°C had less total thaw and cooking loss than steaks broiled frozen (-10°C) or thawed (24°C), but greater muscle separation occurred in thawed steaks. Palatability was not adversely affected by steak location, storage time or steak temperature prior to cooking.

A mechanical counterpart of the Gardner mobilometer is described which gives results in agreement with those obtained on the hand-operated instrument and enables the rate of testing to be increased to sixteen determinations per hour.

Since the Fifth International Congress of Radiology in 1937, there have passed 13 eventful years, both in world history and in science, and although their affairs may seem a small drop in a very large ocean, to all who are interested in the science of radiology, these have been years of dramatic development. These 13 years have seen the firm establishment of a new medical auxiliary specialty which, for want of a better name, we have called radiological physics. It is true that radiological physics was born in 1895 and that ever since that time, physicists in Universities, in Medical Schools and in industry have played an important part in the growth of radiology, but to the majority of physicists working in hospitals to-day, anything prior to Zurich 1934 is probably regarded as almost pre-history, and Chicago 1937 as somewhere in the Middle Ages. In order to see the position in perspective it is interesting to look at some of the conditions obtaining in 1937. A great deal of the equipment for X-ray therap...

The relationship between the occurrence of otitis media during the first 3 years of life and cognitive, academic, and classroom performance during the third year of elementary school was evaluated in 44 socioeconomically disadvantaged children. The children attended a research day-care program where their otitis media experience and psychoeducational development were documented prospectively from birth. No significant relationship was found between otitis media in early childhood and performance on tests of verbal intelligence or academic achievement in the third year of school. The number of days of otitis media before 3 years of age was significantly correlated with teachers' ratings of children's attentional behavior in the classroom, however. Children with more early otitis media tended to be rated as less task oriented and less able to work independently than children with less otitis media. This was an exploratory study of a small number of children. Further study of the potential association is needed.

Calf lens protein was irradiated with near ultraviolet (UV) light in the presence of the drugs chlorpromazine, promazine, and hematoporphyrin. It then was analyzed by SDS-polyacrylamide gel electrophoresis and amino acid analysis. Marked increases in protein photopolymerization (other than S-S bond formation) and histidine destruction were noted in the presence of these drugs. In all cases, these effects were reduced in the presence of a singlet oxygen quencher, thus suggesting that these photodynamic effects are due, at least in part, to a Type II mechanism.

We compared uterine activity in lateral recumbency and the sitting position during the first stage of labor in a group of nulliparas. Lateral recumbency was accompanied by more intense, less frequent and more efficient uterine contractions than sitting. Patients preferred sitting for the first half of labor and lateral recumbency for the second. No adverse fetal reaction was noticed in either position, judging from the fetal heart rate. An increase in maternal pulse rate during sitting could have indirectly indicated some compression of the prevertebral vessels. Maternal position clearly affects several parameters of labor, and its selection should be based upon maternal comfort, uterine contractility and efficiency, and hemodynamic repercussions.

Age related, photochemically induced damage to the lens can eventually lead to light-scattering areas which would be evidenced as an opacification of the lens. These modifications may occur at ambient radiation over an extended period, resulting from the initial absorption of radiation by relatively inefficient endogenous sensitizers (eg. tryptophan and/or 3 hydroxy kynurenine glucoside). However, the introduction of an efficient exogenous photosensitizer into the lens can markedly increase the rate by which these changes occur. Photophysical studies of various excited states of these endogenous and exogenous photosensitizers of the lens help explain these differing rates of photolytically induced damage in the lens.

Fifty parents of 36 consecutive children admitted to hospital with their first febrile convulsion were interviewed shortly after the event. Very few parents voluntarily said that they had thought their child was dying, but when asked specifically the majority said they had thought the child was dying or likely to die. This common fear should be kept in mind when discussing febrile convulsions with parents, who are unlikely to volunteer the information.

A simple, noninvasive clinical test for detecting nuchal cords late in pregnancy and during labor is based on recording the changes in the fetal heart rate produced by transabdominal manual compression of the fetal neck area. The test was applied in 88 women close to full term and to 67 women in labor. Overall, the sensitivity of the test was 82.3% and specificity, 89.1%. The results were statistically significant in both late pregnancy and labor. A positive test implies an impending risk of cord compression and is an indication for close electronic fetal monitoring, particularly during labor. Routine use of the nuchal cord test can contribute to decreasing perinatal morbidity and mortality by diminishing the impact of cord problems.

The relationship between the occurrence of otitis media with effusion during the first 3 years of life and subsequent verbal and academic performance was examined in 61 socioeconomically disadvantaged children who attended a research day-care program. Study children were participants in a longitudinal study of child development in which the number of episodes of otitis media and duration of each otitis episode were reported prospectively from infancy. The incidence of otitis media was highest during the first 2 years of life. Bilateral otitis media accounted for 66% of the days with otitis media with effusion. Standardized tests of intelligence and academic performance were administered to the children when they were 3 1/2 to 6 years of age. No evidence of associations between measures of early childhood otitis media experience and these measures of verbal or academic functioning was found in this study population.

Electron-nuclear double resonance spectra of horseradish peroxidase Compound I exhibit resonances from 14N and beta-protons, and most probably alpha-protons as well. The measurements prove that the oxyferryl iron of this enzymic intermediate is spin-coupled to a porphyrin radical. Comparison of experimentally obtained average pi-electron spin densities with theoretical predictions for a 4-fold symmetric porphyrin pi-cation radical is supportive of a 2A2u assignment for the radical's electronic state.

We have collected electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) spectra from the hydrogen peroxide compound of yeast cytochrome c peroxidase, termed ES, employing EPR microwave frequencies of 9.6 and 11.6 GHz. We have measured and analyzed the temperature dependence of the spin-lattice relaxation rate (1/T1) of the paramagnetic center of ES over the temperature range 1.9 to 4 K. In addition, an upper bound to exchange coupling between the ferryl heme and EPR-visible centers of ES has been calculated and expressions for the dipolar interaction between a ferryl heme and a free radical have been derived. These results all confirm that the EPR signal of ES is not associated with an aromatic amino acid radical, and in particular not with a tryptophanyl radical. This conclusion has led us to consider an explanation of the EPR signal in terms of a nucleophilically stabilized methionyl radical.

Except for bone mineral, the body is shown to belong to the same water:fat:protein system as its soft tissues. Hence, an equation verified with a variety of freshly isolated tissues can be used to estimate the body fat and the so-called total tissue solids. On the average, there are 0.784 kg of water/kg of body weight less bone mineral and fat. However, this water content probably fluctuates between extremes of 0.816 and 0.752, in accordance with the time elapsing since imbibing much water. This causes the density of the tissues in the fat-free, bone mineral-free body to range from 1.050 to 1.071. Combined simultaneous measurements of water, density and bone mineral, therefore, are required for the estimation of fat and tissue solids. Bone mineral occurs in the proportion of about one part to three parts of tissue solids, irrespective of ranges in quantities of fat and water among 30 healthy persons. Submitted on June 15, 1959

From I(131)-albumin studies and previously defined mathematical formulations, rates of breakdown were estimated for native plasma albumin in rabbits. These rates of catabolism per unit weight of animal were remarkably constant and were independent of variations in the steady state values of albumin concentration in the plasma. These results imply that, at least between animals, the breakdown of plasma albumin follows a kinetic process of approximately zero order. It seems plausible that the process operates similarly in individual animals, and hence that albumin is maintained at normal steady state levels in the healthy animal primarily by means of a regulated rate of synthesis.

Summary and ConclusionsQuantitative limitation of food intake sufficient to account for average body-weight differences of 55% between underfed and litter-mate control rats, has also resulted in statistically significant differences in myelination of the optic tracts and nerves. The concentration of myelin in the optic tracts of the underfed rats has averaged 20% less than that in the control animals. Since myelination of the optic tracts, as shown by spectrophotometric determinations in litter-mate rats at successively older ages, is not complete until sometime between the 40th and 50th days, the conclusion seems justified that the relative lack of myelin observed in the underfed animals is due to partial or complete arrest of the process of myelination.