bluuebunny/crossref_metadata_2025 huggingface dataset:
Emergency Medicine Clerkship Encounter and Procedure Logging Using Handheld Computers
Authors: Penciner Rick , Siddiqui Sanam , Lee Shirley
Published: June 2007

BackgroundTracking medical student clinical encounters is now an accreditation requirement of medical schools. The use of handheld computers for electronic logging is emerging as a strategy to achieve this.

ObjectivesTo evaluate the technical feasibility and student satisfaction of a novel electronic logging and feedback program using handheld computers in the emergency department.

MethodsThis was a survey study of fourth‐year medical student satisfaction with the use of their handheld computers for electronic logging of patient encounters and procedures. The authors also included an analysis of this technology.

ResultsForty‐six students participated in this pilot project, logging a total of 2,930 encounters. Students used the logs an average of 7.6 shifts per rotation, logging an average of 8.3 patients per shift. Twenty‐nine students (63%) responded to the survey. Students generally found it easy to complete each encounter (69%) and easy to synchronize their handheld computer with the central server (83%). However, half the students (49%) never viewed the feedback Web site and most (79%) never reviewed their logs with their preceptors. Overall, only 17% found the logging program beneficial as a learning tool.

ConclusionsElectronic logging by medical students during their emergency medicine clerkship has many potential benefits as a method to document clinical encounters and procedures performed. However, this study demonstrated poor compliance and dissatisfaction with the process. In order for electronic logging using handheld computers to be a beneficial educational tool for both learners and educators, obstacles to effective implementation need to be addressed.
Pressure-vessel support brackets: Stresses due to dead loads
Authors: Kitching R , Olsen B E
Published: June 2007

The investigation is concerned with the elastic shell stresses occurring when vertical loads are transmitted through discrete support brackets welded to the lower hemispherical end of a cylindrical pressure vessel having its axis vertical. Three sizes of bracket were examined, and the largest was compared with a similar arrangement having an internal bracket continuous with the external one. Strain-gauge results indicated that shell stresses may be calculated by assuming that the radial deflection of the spherical shell is linearly distributed along the line of contact between bracket and shell. Conventional design methods employed in stress calculations tended to underestimate the shell stresses.

It is shown that the line of application of the support reaction in relation to the centre line of the bracket is most important.
Stress discontinuities in plane plastic flow
Authors: Ellis F
Published: June 2007

Statically admissible stress fields consisting of regions of constant stress in a state of incipient plastic flow separated by stress discontinuities form a powerful tool for obtaining lower bound solutions to problems in plane plastic flow.

The properties of discontinuities which meet on an axis of symmetry are investigated and it is shown that solutions exist for ‘reflections’ of the discontinuity at the axis at angles of π/4 and 3π/4 as well as the angle π/2 hitherto assumed to be the only solution.

The results are used to obtain a lower bound solution for plane-strain extrusion with reduction ratios less than 3:1.
Plastic flow and instability behaviour of thin-walled cylinders subjected to constant-ratio tensile stress
Authors: Jones B H , Mellor P B
Published: June 2007

The plastic instability of thin-walled tubes subjected to internal pressure and independent axial load is investigated. Theoretical treatments of the problem are discussed, in particular the plastic straining of tubes under constant ratio of circumferential to axial stress. The concept of a thin-walled tube is an approximation, the accuracy of which varies with stress ratio. It is shown that taking the stress and strain measurements with reference to the central section of the tube wall gives a good approximation. Thick-walled theory is, therefore, necessary to relate the circumferential strains measured at the outer surface to the strains existing at this central section.

The material tested was a nickel-chrome steel, S62, under stress ratios of 0, 0.5, 1.0, 2.0, and ∞. Measurements of strains, pressures, and loads were recorded continuously and it was possible to keep a constant ratio of true stress, as opposed to constant ratio of nominal stress which has been more often adopted.

Correlation between theoretical and experimental instability strain was good except for stress ratios of 0.5 and ∞. In all cases fracture was preceded by a definite instability condition.
Elastic-plastic behaviour of pipe bends with in-plane bending
Authors: Marçlal P V
Published: June 2007

The theory for the in-plane and out-of-plane bending of a curved pipe is reviewed by considering it as an extension of the theory for symmetrically loaded shells of revolution. This treatment is adopted with the intention of modifying an existing elastic-plastic programme for shells of revolution so that it can perform the analysis of pipe bends with in-plane bending. Results are presented for elastic and elastic-plastic behaviour of pipe bends with in-plane bending. These results agree with theoretical and experimental results found in the literature.
Short-life fatigue under combined stresses
Authors: Libertiny G Z
Published: June 2007

Most of the short-life fatigue tests have been carried out in push-pull or in reversed bending. Many machine parts and structural elements, however, are subjected to combined rather than uniaxial fatigue loads. This work is intended to demonstrate a possible approach to solving the problem of short-life fatigue failures due to a multiaxial stress-strain system.

The paper includes a review of the available literature relevant to the problem. The more important experimental findings are summarized and presented in the form of diagrams. Various approaches toward the solution of the problems are discussed, and a new approach is proposed.

It is demonstrated in this paper that the use of an ‘equivalent-strain parameter’ calculated from the Mises law is not suitable in the description of the problem. It was found that when the strain Δ∊ in the direction of the maximum stress is adopted as a strain parameter and a stress-dependent parameter L is introduced, all of the results can be described by the following equation:

        Δ∊ Na = C

where n = f( np, L) and C = f( Cp, L),

    Δ∊ = cyclic strain range,

     N = number of cycles to failure,

     np = slope of the log ∊-log N curve which represents a push-pull fatigue test,

     L = stress parameter,

     Cp = constant in the log ∊-log N curve which represents a push-pull fatigue test.

These functions have been determined approximately.

It is recognized that, because of lack of experimental data, the present work can indicate only a possible and somewhat speculative approach and that there is a great need for further experimental work.
Evaluation of grid data to determine displacements and strains
Authors: Durelli A J , Parks V J , Feng H
Published: June 2007

This paper deals with a new method to evaluate distorted grids. Instead of evaluating point-by-point the new method consists of shifting an image of a distorted grid over another image of the undistorted grid to obtain displacement components, or shifting an image of a distorted grid over another image of the same distorted grid to obtain the derivative of the displacement components. Whole field information is available by connecting grid line intersections.

Displacements and their spacial derivatives are given for a circular ring diametrically compressed, using both the Eulerian and the Lagrangian descriptions. The method has applications in plasticity and in elastic finite strain determinations.
An investigation into the existence of corners on the yield surface
Authors: Mair W M
Published: June 2007

Three metals were subjected to zig-zag stress paths in the plastic region. The direction of the plastic strain increments suggested local distortion of the yield surface rather than the formation of a sharp corner.

A stepped stress path with unloading between steps gave strain increments consistent with a distorted but smooth yield surface, rather than one with plane segments.
Velocity field and strain-rates in plastic deformation
Authors: Hsu T C
Published: June 2007

Grid lines have often been scribed, printed or photographed on metal surfaces for studying plastic deformation. Hitherto, most of them have been used only for qualitative results. It has been shown in a previous paper (2)∗ how quantitative results on finite deformations can be derived from a deformed grid. As a sequel to that paper, a method is presented here for deriving the rates of deformation from deformed grids. The relation between the velocity field on the one hand and the strain-rates and rotations on the other is first discussed. The theory thus developed is then applied to the cases of steady-state and non-steady-state flow, with practical example for the former. The connection between finite deformation and rate of deformation is also explained.
Behaviour of filament yarn wound on a flanged cylinder
Authors: Neal B G
Published: June 2007

After manufacture, some synthetic fibres are wound under tension on a flanged cylinder, and a knowledge of the pressures exerted by the yarn on the flanges and on the cylinder is required for design purposes.

During winding, the pack of yarn may behave as an elastic solid, flange pressure being generated by the partial prevention of longitudinal expansion. However, it is also possible that the fibres may undergo a relative slipping movement and tend to slide off the ends of the cylinder. Flange pressure would then be developed in order to inhibit further slip.

These two possibilities are examined on the assumption that the yarn has isotropic elastic properties. Although it is known that drawn fibres possess considerable anisotropy, these analyses are a prelude to studies of anisotropic behaviour.
Strain and rupture behaviour under high-stress reversals
Authors: Tilly G P
Published: June 2007

A rheological approach to fatigue behaviour has been extended to the push-pull fatigue of an 11 per cent chromium steel and a nickel-chromium alloy at room temperature and the influence of the direction of first loading stroke has been examined. At the high stresses involved, strain was shown to accumulate ultimately in a tensile direction in a manner similar to elevated temperature creep and the strain-time curves were shown to have the form ∊ = Σ Cσβtκ where ∊ is strain, σ is stress, t is time, β and κ are discrete exponents, and C is a material constant. The widths of the hysteresis loops (strain amplitudes) were found to be dependent upon time in a manner similar to the cumulative strains and were analysed by a similar expression.

The growth of tensile strain occurred irrespective of whether tension or compression was applied first but the application of compression first caused lower values of cumulative strain and longer endurances for similar load limits.
Elastic-plastic behaviour of thin tubes subjected to internal pressure and intermittent high-heat fluxes with application to fast-nuclear-reactor fuel elements
Authors: Bree J
Published: June 2007

A sealed reactor fuel can when subjected to sufficiently high thermal stresses in the presence of an internal pressure will yield plastically. A simple model of the can is used to show that the plastic strains so produced may cause ratchetting or plastic cycling as the temperature gradient across the can wall cycles because of startup and shutdown of the reactor. On the assumption that creep is negligible, approximate criteria are derived for the onset of ratchetting and plastic cycling, simple expressions are obtained for the plastic strains incurred by each cycle, and failure of the can due to the above mechanisms is discussed both for work-hardening and non-work-hardening material. Consideration is then given to the effect of stress relaxation due to creep when the mean temperature of the can is sufficiently high to cause complete relaxation of the thermal stress while the reactor is at power, creep being ignored while the reactor is shut down. Under these conditions, it is found that the criterion for ratchetting is simply the criterion for plastic yielding during the first temperature cycle. Finally, it is shown in an appendix that the results obtained from the simple model also hold, with minor modifications, for the similar problem of a thin spherical shell subjected to an internal pressure and a temperature gradient across the shell wall which is cycled. Use is made of this to discuss the accuracy of the results obtained from the simple model when applied to a thin can.
A sheet-bulging machine with closed-loop control
Authors: Bell R , Duncan J L , Wilson I H
Published: June 2007

The design and performance of a machine for testing sheet material in the plastic range is described. The material is stressed in uniform biaxial tension by means of the hydrostatic bulge test. Test variables are measured by electrical transducers and an analogue unit is employed to permit autographic recording of the diagram relating true stress and natural strain. Closed-loop control of the rate of straining is achieved with an electro-hydraulic actuator; the feedback signal is derived from the analogue unit and the test can be controlled on the basis of a computed parameter such as true stress or natural strain.
Effect of strain hardening and speed effect on the strain distribution in rods under impact
Authors: Davis E A
Published: June 2007

The distribution of the stress, strain, and strain rate in a long rod, one end of which has been given a fixed velocity, is analysed. Computer programmes have been written for three different classes of materials: purely rate-sensitive materials, purely strain-hardening materials, and materials exhibiting both strain hardening and speed effect. Where possible the results have been checked against known solutions.
An experiment in stress redistribution caused by creep
Authors: Barnes J F , Clarke J M , Clifton T E
Published: June 2007

A simple redundant structure subjected to a non-uniform temperature distribution is simulated experimentally by means of two tensile-creep test machines holding specimens of Nimonic Alloy 90 at different temperatures in the range 800-900°C. The machines are linked together so that although the total load applied to the specimens is constant the share of that load taken by each varies owing to dissimilar creep rates, as it would in the structure. This redistribution of load is observed for several initial stress conditions and several temperature differences. In each case the results are compared with calculations based on creep-strain data obtained from constant-stress tests. An important practical feature of the results is the establishment of stable (fully redistributed) stresses. These stresses are insensitive to the initial conditions, can be estimated quite simply from constant-stress creep data, and are always more uniform than the thermal stresses appropriate to the same temperature difference. There is some indirect evidence that the creep process itself (primary creep in particular) is a manifestation of stress redistribution on a microscopic scale.
High-strain fatigue of stainless-steel cylinders: Experimental results and their application to pressure-vessel design
Authors: Ruiz C
Published: June 2007

Thin cylindrical specimens, plain and with deep axial grooves, have been tested under pulsating pressure and under static pressure with cyclic axial straining. The test results, together with some supplementary information from other authors, show that Langer's method, based on an elastic-stress analysis, is applicable to the fatigue design of pressure vessels. Design curves for the establishment of the acceptable elastic-stress range corresponding to a given fatigue life are proposed. Attention is drawn to the limitations of Langer's method.
Behaviour and simulation of sedimentary rocks
Authors: Hobbs D W
Published: June 2007

Investigations on the elastic properties and strength of sedimentary rocks in uniaxial and triaxial compression and on the tensile strength of sedimentary rocks are described. A brief account is given of the application of dimensionless analysis to scale-model roadway tests and of the properties of a scale-model material.
Relations between crack opening displacement and hoop stress in zircaloy-2 pressure tubes containing axial defects
Authors: Parry G W , Mills R G
Published: June 2007

Analysis of the end-of-slit opening measurements in Zircaloy-2 pressure tubes containing axial through-the-wall defects as a function of hoop stress has shown that the experimental data do not conform to yielding behaviour as predicted for cracked flat plates. It is shown, however, that the results agree closely within certain limits of crack opening displacement with flat-plate behaviour if they are corrected by a non-dimensional geometrical correction as given by the equation

δ = 8σya/πE(ln sec β)(1+1·6 a2/Rt)

Deviation from the equation occurs at values of δ exceeding about 0.010 in and is possibly due to gross-bulging effects.
Creep of hollow concentric tubes
Authors: Blackburn W S
Published: June 2007

For a thin outer tube of non-linearly creeping material with a sharp yield stress surrounding a thick inner tube of linearly creeping material with a sharp yield stress which is swelling at a constant rate, the conditions in which each tube is plastic and in which each tube creeps have been determined for the conditions of zero axial load and zero axial strain. Equations yielding the ratios of the axial and circumferential creep rates of the outer tube to the swelling rate of the inner have been determined in terms of the material parameters for each of the above conditions and have been solved on the assumption that these ratios are small.
Investigation of the creep of fuel-element cans under internal pressure using a damage-function creep theory
Authors: Blackburn W S
Published: June 2007

The creep deformation of an internally pressurized fuel-element can in the presence of superposed cyclic thermoelastic stresses is investigated. The period of significant primary creep is comparable with that of the cycle. Hence it is necessary to develop a more complex theory than that of time or strain hardening. The simplest of such theories based on dislocation behaviour but in which the material parameters occurring may be determined from simple experiments was chosen. For an austenitic steel this theory gave good agreement with both creep and relaxation tests. It was applied therefore to the problem of the fuel-element can. It was found that in practice the increased damage caused by the cycling over-compensated for the effect of the increased stress so that the material did not deform as much as when there was no cycling.
Use of plastic models to evaluate thermal strains in diesel-engine pistons
Authors: Lawton B
Published: June 2007

The paper presents a low-temperature plastic-model technique for the simulation of thermal strains in diesel-engine pistons. Various difficulties in obtaining accurate thermal-strain measurements from resistance strain gauges attached to plastics are discussed. These difficulties include: the formation of a hot spot under the gauge, caused either by the low-conductivity gauge or by the electrical power dissipated by the grid; the apparent strain characteristics of gauges mounted on plastics; reinforcement of the model by the gauge; irreversible expansion of the plastic causing zero drift. An application of the technique is given, and the service failure of a 19-in diameter piston crown is explained.
Stress-strain characteristics of thermoplastics at constant rates of loading
Authors: Ogorkiewicz R M , Culver L E , Bowyer M P
Published: June 2007

The paper describes the development of a uniaxial tensile test, at constant loading rate, for thermoplastics and compares the results obtained with those from tests at constant rate of elongation and constant stress.
Fracture-mechanics analysis of fatigue-crack propagation in polymethylmethacrylate
Authors: Borduas H F , Culver L E , Burns D J
Published: June 2007

Repeated tension tests on centre-notched sheet specimens show that the rate of growth of fatigue cracks in polymethylmethacrylate is constant if the range of crack-tip stress-intensity factor is constant. Within the limits considered fatigue-crack growth rate was independent of specimen thickness and loading history.
Photoelastic analysis of stresses and forces in steady cutting
Authors: Amini E
Published: June 2007

The results are presented of tests conducted at three different depths of cut and a velocity of 3.1 m/min on a work-hardening lead-alloy workpiece with a 10-degree-rake photoelastic tool. In addition to examining the behaviour of the chip-tool contact stresses, the paper considers the forces acting on the tool and distinguishes three areas: rake, nose, and flank. It evaluates the rake forces from the photoelastic results directly, estimates the nose forces by making certain assumptions with regard to the distribution of stresses, and neglects the stresses on the flank. The sum of the forces so obtained is then compared with the measured resultant cutting force; there is good agreement.

There is a particularly significant observation which, contrary to previously published results, shows that the frictional stresses vary linearly in the so-called sticking zone and tend towards a constant only at relatively high depths of cut. This is discussed in relation to the general concept of plastic friction and the variation of the coefficient of friction on the rake face. The significance of the measured resultant coefficient of friction is also considered.
Elastic stresses in torispherical drumheads: Experimental verification
Authors: Findlay G E , Moffat D G , Stanley P
Published: June 2007

Four steel torsispherical drumheads, machined from oversized blanks and welded to drums of approximately equal thickness, have been tested under internal pressure within the elastic range. The resulting stress distributions are compared with results obtained from photoelastic analyses of geometrically similar models and with two independent computed solutions for each of the four shapes. Important differences are found between prototype and photoelastic results for the two thin shallow heads. Otherwise there is a good measure of agreement between the different stress distributions for each head.
Increase in ovality of uranium tubes due to creep under external pressure
Authors: Blackburn W S , Percy J
Published: June 2007

The increase in ellipticity of a concentric slightly elliptical tube is theoretically investigated for the case of external pressure and radial temperature gradient when the creep rate is proportional to the stress and the constant of proportionality varies slightly between the principal axes.

The presence of a radial temperature gradient accelerates the increase in ovality due to initial ovality on the outer surface and that due to circumferential variation of strength (except after very small collapses) and decreases that due to initial inner ovality. Further allowance for circumferential variation in temperature, due to an insulated inner surface and to a uniform heat-transfer coefficient to a gas at constant temperature around the outer surface, reduces the increase in all cases.
Laboratory investigations of cutting processes applied to coal-winning machines
Authors: Pomeroy C D , Brown J H
Published: June 2007

Laboratory experiments on cutting mechanics in coal are described, and the conclusions reached are tested in underground trials on standard coal-winning machines. In general the laboratory findings are verified but such discrepancies as are observed are attributed to the fact that in the laboratory the cutting process is studied independently of the flow of broken coal from the cutting zone, whilst in some underground applications the forces and power needed to move and cause secondary degradation of the extracted coal can swamp the true cutting forces.
Rate of deformation and redundant shears in the combined rotary piercing-elongating process
Authors: Blazynski T Z
Published: June 2007

The ultimate success of the new combined rotary piercing-elongating process for tube making will depend on the possibility of lessening the inherent severity of the operation. The reduction in the incidence and magnitude of redundant shearing strains will be therefore of primary importance.

The present work examines, experimentally, the influence of the predetermined rate of deformation on the redundant shear in the pass. It is shown that there exists a well defined relation between these strains and the geometry of the pass, and, hence, the rate of deformation.

It is concluded that a range of low feed angles should be used, and that a feed angle of 8°, combined with the decelerated rate in the piercing zone of the pass and a uniform rate in the elongating zone, is likely to provide a satisfactory compromise between the velocity requirement and the quality of the finished product.
Effect of strain rate on low-endurance torsional fatigue in commercially pure aluminium
Authors: Miller K J , Rizk M N
Published: June 2007

Commercially pure (99 per cent) aluminium has been subjected to high-strain low-endurance torsional fatigue under conditions of constant strain rate. (In this paper ‘strain’ and ‘strain rate’ refer to conditions at the surface of the specimen and therefore apply to the zones in which cracks are initiated.) Tests were performed at 20°C (0.315TM) and were controlled between constant torque limits of equal but reversed magnitudes. Below a critical strain rate, ·λcrit, the fatigue life obeys the law

Nf = A·λm

for a constant torque range. When ·λ exceeds ·λcrit, there is no significant strain-rate effect on fatigue endurance. It is suggested that cyclically activated creep mechanisms cause significant damage at strain rates less than 2Tcrit.

A relaxation behaviour was observed after the first quarter cycle when torque ranges were greater than a critical level of 2 Tcrit. A similar phenomenon was observed at ranges less than 2 Tcrit with straining rates less than 2Tcrit but only when the specimens were close to failure and the initial cyclic hardening had been removed by cyclic softening. In consequence fatigue endurances were found to be less sensitive to torque at ranges greater than 2 Tcrit.

Cumulative strain (cyclically induced creep) occurred at all torque ranges and straining rates. Minimum cumulative strains occurred at a torque range of 2 Tcrit with the value of Tcrit having a minimal dependence on the straining rate.

The ratio of time to cyclic-dependent processes that contribute to failure is itself dependent on both the torque range and the straining rate. However, a single curve suffices to represent all results if a total strain path to failure criterion is adopted.
Axial stresses in cylindrical tube-plates
Authors: Fessler H
Published: June 2007

Photoelastic frozen-stress tests were carried out on two identical vessels, one subjected to pure bending, the other to axial tension simulating pressure end-load only. The arrays of holes were designed for maximum ‘eccentricity’.

The pressure end load causes stress variations of the type assumed in B.S. 1113:1958 calculations. The measured eccentricities from the bending test show that the eccentricity, which is ignored by the A.S.M.E. and I.S.O. codes, is real but not as great as predicted by B.S. 1113:1958. A proposed method of calculation gives the best agreement with the observed eccentricities but the B.S. method predicts the mean axial stresses well.

The usual method of averaging the diameters of adjacent unequal holes for stress calculations is satisfactory.
Approximate analysis of transient creep deformation
Authors: Marriott D L
Published: June 2007

A method has been proposed which approximates transient creep behaviour by the superposition of elastic and steady-state creep deformation. The present paper discusses the errors incurred by this method. It is shown that they are small. Equations are derived which enable corrections to be calculated with moderate accuracy for an important group of creep theories. Some numerical examples are included for comparison.
Strain concentration in beams under cyclic plastic straining
Authors: White D J , Radomski M
Published: June 2007

Cyclic plastic-straining tests with controlled deflections have been conducted on beams subject to uniform bending, three-point bending, and a cosine distribution of bending moment; the second and third beams represent cases of strain concentration. Three different materials were used, namely mild steel, stainless steel, and aluminium.

The strain-concentration tests show stainless steel and aluminium to be more resistant to deflection cycling than mild steel. A similar difference is not found in the uniform bending tests to anything like the same extent. Stainless steel shows a more pronounced strain-hardening characteristic in the cyclic stress-strain curve than does mild steel and it is concluded that this produces a more favourable strain distribution along the length of the beam, so that the maximum strain is less and the endurance is correspondingly greater.

For materials which show settled cyclic stress-strain relations, reasonable predictions may be made of life in deflection cycling of beams under strain-concentration conditions if the strains are calculated from the cyciic relations and the corresponding endurance is obtained from uniform bending tests. If, for design purposes, the strains determining the life are calculated from monotonic stress-strain relations, the design will be safe, provided the material does not soften with cyclic straining.
Chemical-induced chromosome damage
Authors: Dean B. J.
Published: June 2007

The development of methods for the investigation of chemical-induced chromosome damage is described using either bone marrow cells from rats and mice, or cultured rat leucocytes. The application of these methods to 4 biologically active compounds is demonstrated, and the value of such compounds as control materials for similar investigations is discussed.
Some aspects of the physiology of the anaesthetised marmoset
Authors: Davies J. A.
Published: June 2007

Some normal values of blood pressure, heart rate, and respiration rate obtained from 37 anaesthetised marmosets, are reported together with results of the electrocardiograms of 6 marmosets. The effects of a variety of pharmacological agents are also reported.

The suitability of the anaesthetised marmoset as a representative of the primate order for the pharmacological evaluation of drugs that affect the cardiovascular and respiratory systems is discussed.
The Weizmann Institute Laboratory Animals Breeding Center
Authors: Benhar E. , Zarhy M.
Published: June 2007

The layout and construction of the new laboratory animal breeding centre at the Weizmann Institute of Science are described, and the building costs are given. The functions and general working procedures of gnotobiotic and diagnostic laboratories, as well as of the SPF unit are explained and discussed.
Sterilization of laboratory animal diets using gamma radiation
Authors: Ley F. J. , Bleby J. , Coates Marie E. , Paterson J. S.
Published: June 2007

Sterilization by gamma radiation has proved to be a suitable method for the treatment of a variety of laboratory animal diets intended for specified-pathogen-free (SPF) and germ-free colonies. Due to the high penetrating power of this radiation the diets can be packed before treatment in a manner which prevents recontamination during transport and storage. The main bulk of diets is used for SPF animals and a radiation dose of 2.5 Mrad has proved effective for the control of contaminating organisms. No adverse effects on animals receiving the diets have been noted, observations having been made on growth, reproduction and general health. Irradiated diets formulated according to current laboratory animal practice appear to be nutritionally satisfactory.
Automation of skeletal staining in the evaluation of teratogenicity
Authors: Randle A. D.
Published: June 2007

A number of variables affecting the quality of foetal mouse preparations stained with alizarin red S have been investigated. A seven-day 'Histokinette' procedure has been developed to macerate and stain foetal mice by a modification of Dawson's method.
Body weight ratio of male and female rats reared on various diets in relation to food efficiency ratio and longevity
Authors: Dalderup L. M.
Published: June 2007

The ratio of the bodyweights of male and female rats, together with the weight of the females, seems to give valuable information as to the biological value of an experimental food as a whole and to the lifespan expectancy. Extremes of the bodyweight ratios are 0.9 and 2.0, the lower ratios applying to younger age groups and to old animals, the higher ratios to the ages in between. There is evidence that diets which are most favourable with regard to longevity give rise to maximum ratios between 1.5 and 1.6, which are maintained during later life. The females give always less response to dietary measures and are less disturbed by very bad quality rations than the males. Their lifespan is often longer than that of the males.

The bodyweight ratio has within reasonable limits the same numerical value as the ratio of food efficiencies of male and female animals; the weight ratio is always very simple to obtain, whereas measurement of food-efficiency ratio requires much more work.
Histopathological changes in the pancreas of laboratory rats
Authors: Kendrey G. , Roe F. J. C.
Published: June 2007

'Chronic relapsing pancreatitis' was seen in 81 per cent of 108 rats of 3 inbred strains. Clinically, even in advanced cases, there were no symptoms of disease and the physical status of the animals was satisfactory. The least histological sign of involvement was a decrease or loss of cytoplasmic basophilia in acinar cells in some lobules, and infiltration of the intralobular connective tissue by mononuclear cells. More severe forms of the disease were characterized by flattening of the epithelium of acini by 'microcystic-transformation' of the gland, and fatty atrophy. Fibrosis of the connective tissue and dilatation of the ducts were usual events. In few cases 'polyarteritis-like' lesions of the arteries of the pancreas were observed. Microbiological investigation of the aetiology is in progress.
Haematological values of the multimammate mouse Praomys (Mastomys) Natalensis
Authors: Martin K. , Rutty D. A.
Published: June 2007

The haematological estimates on 55 multimammate mice, Praomys (Mastomys) natalensis, are recorded. The data are presented as means, standard deviations and ranges or confidence limits.
Sublingual vein injection in rodents
Authors: Waynforth H. B. , Parkin R.
Published: June 2007

A simple and rapid technique for intravenous injection into the sub-lingual veins of common laboratory rodents is described. No prior preparation other than light anaesthesia is required and repeated injections can be made into the same vein.
Breeding the chinese hamster (Cricetulus griseus) in monogamous pairs
Authors: Porter George , Lacey Alma
Published: June 2007

A simple method for the selection of Chinese hamsters ( Cricetulus griseus) that will breed in monogamous pairs is discussed. The establishment of a small colony of non-aggressive Chinese hamsters that reproduce satisfactorily in conventional cages under normal animal-house conditions is described. The method of management and the frequent handling of the animals have contributed to the successful establishment of the colony.
Results of bacteriological testing of germ-free laboratory animals
Authors: Cook R. , Bishop A.
Published: June 2007

Methods used to detect bacterial contaminants in germ-free laboratory animals are described. Contaminating organisms usually establish themselves permanently in the gastro-intestinal tract but in one instance a species of Corynebacterium was isolated from samples of faeces from a group of rats over a period of five days, after which it disappeared and could not be subsequently isolated. Attention is drawn to changes in management technique which resulted in a marked decrease in the occurrence of contamination.
A simplified fibreglass germ-free isolator with facilities for performing dental surgery on rats
Authors: Paterson R. C. , Jones R. W. , Cook R. , Garriock D.
Published: June 2007

An isolator constructed in fibreglass was equipped with facilities for performing dental surgery on germ-free rats and then maintaining them in the germ-free state for a period following the surgical procedure. The main unit was sterilised with peracetic acid, and the ancillary equipment by gamma radiation.
A mobile shelving unit for laboratory animal cages
Authors: Coid C. R.
Published: June 2007

The rack is 73 in high x 36 in wide x 27 in deep overall (185 x 90 x 70 cm). It is constructed in 2 sections, of approximately equal size, from steel tubing coated with nylon after manufacture. The shelves, which may be located easily in different positions, are made from aluminium sheeting.

This type of free-standing unit provides a very satisfactory degree of the adaptability which is frequently required to accommodate laboratory animal cages of various sizes.
Device for the experimental production of thermal burns in laboratory animals
Authors: Malik M. O. A.
Published: June 2007

A new 'burning iron' device for the experimental production of contact burns in laboratory animals is described. It allows for a constant surface area to be treated at a controlled temperature. The burns can therefore be reproduced from animal to animal and from laboratory to laboratory, and the graded effects of temperature can be satisfactorily studied. The device is simple to assemble and operate, and safe to handle.
Litter differences in cross-fostered rats
Authors: Brown P. S. , Wyatt A. C.
Published: June 2007

Rats, marked to identify their litters of origin, were cross-fostered when 2 or 3 days old into all-female groups of 10 young. After weaning, their response to injected gonadotrophin showed significant differences among litters but not among cross-fostered groups.
Appearance of keratitis in laboratory mice: influence of azathioprine and meticorten
Authors: Kaplun Amihud , Barishak Robert Y.
Published: June 2007

Keratitis was noted in mice which were splenectomized and subsequently treated with immunosuppressive drugs. It was found that anaesthesia was the cause of the lesion and not the azathioprine or meticorten administration.
Decomposition of supplementary vitamin C in diets compounded for laboratory animals
Authors: Eva J. K. , Fifield R. , Rickett M.
Published: June 2007

Processing may result in losses approaching 20% of the added vitamin C. The extent of these losses depends upon the process and is apparently related to temperature and moisture. Storage losses are also related to processing conditions, and no more than 50% of the vitamin C present in the diet immediately after processing may remain after 6 weeks. These results indicate that the current practice of including 1000 mg/kg of vitamin C in pelleted guinea-pig diets should be satisfactory, provided such diets are used within 6 weeks of manufacture and are stored during this period in conditions conducive to stability, that is dry, not exposed to direct sunlight and, preferably, with an even cool temperature.
Evaluation of the sub-human primate tube test for pregnancy in primates
Authors: Hobson B. M.
Published: June 2007

A haemagglutination inhibition test, developed specifically for primates, diagnoses early pregnancy in the chimpanzee, gorilla, orang-utan and baboon. The test was sensitive and reacted positively when the concentration of gonadotrophin in urine was equivalent to 0·03 i.u. human chorionic gonadotrophin per ml. This degree of sensitivity and the certitude that it cross-reacts with primate luteinizing hormone probably accounts for most of the false positive results.
Deposition of amyloid in the liver of hamsters: an enzyme-histochemical and electron-microscopical study
Authors: Gruys E. , Timmermans H. J. F. , Van Ederen Anne-Marie
Published: June 2007

In induced amyloidosis the amyloid was first deposited in the portal areas, then in the centre of the lobule and disseminated through it in the spaces of Disse. No intracellular amyloid was found in the predeposit phase. In the hepatic lobule both mononuclear phagocytes and hepatocytes showed a topographic relationship to the first deposits of amyloid. Some macrophages showed invaginations or vacuoles containing amyloid fibrils. Between the microvilli of hepatocytes, parallel amyloid fibrils occurred. Between the amyloid fibrils were 30-50 nm membrane-bounded spherical particles which may have been lipoprotein aggregates. There was no large-scale phagocytosis of amyloid during the induction period or after survival without casein treatment up to 18 weeks. Lysosomal enzyme activity was seen in the deposits of extracellular amyloid.
Studies on Tyzzer's disease: transplacental transmission of Bacillus piliformis in rats
Authors: Fries A. Schaich
Published: June 2007

Clinically healthy rats with antibodies to Bacillus piliformis were given prednisolone in the last week of pregnancy. B. piliformis was demonstrated in the livers of their offspring. None of the dams or the young rats showed clinical signs of disease. Antibodies to B. piliformis were found in the young rats at birth, and persisted for several months. The importance of potential transplacental infections when attempting to establish colonies free from B. piliformis is discussed.
Studies on salmonellosis in the house mouse, Mus musculus
Authors: Shimi Ahmad , Keyhani Massoud , Hedayati Khosrow
Published: June 2007

Salmonellae were isolated from the faeces from 17 of 170 (10%) wild house mice. Salmonella typhimurium was isolated from 10, S. typhimurium, var. Copenhagen from 2, S. thompson from 1, and S. muenchen from 4. It was concluded that house mice could be a reservoir of infection and play an important role in human and animal salmonellosis.
Studies on Tyzzer's disease: a long-term study of the humoral antibody response in mice, rats abd rabbits
Authors: Fries A. Schaich
Published: June 2007

Mice treated with an antigen prepared from livers infected with Bacillus piliformis developed antibodies to the microorganism which reached a peak on the 7th day and disappeared within 40 days: antibody titres in experimentally-infected mice remained at a high level throughout life. The antibody titres in naturally-infected mice, rats and rabbits remained positive throughout life and followed the same pattern as that of the experimentally-infected mice.
Peak littering and the stud male in relation to virgin and remated female P(SD) mice
Authors: Eveleigh J. R. , Gunner Marjorie , Haslam Felicity
Published: June 2007

Peak littering occurred on the 22nd day after pairing. The percentage of pregnancies from virgin females increased as the stud males became more experienced; their success with remated females showed a more varied and lower response.
Catheterization of the left cardiac ventricle of the rat
Authors: Smith S. M. , Myers J. H. , Kaplan H. M.
Published: June 2007

A simple procedure is described of catheterizing the left ventricle of the anaesthetized rat.
Bacteriological examination of a modern animal house containing small laboratory animals
Authors: Wierup Martin
Published: June 2007

Floors and other areas totalling 1800 m2, comprising conventional and specified-pathogen-free (SPF) units, were screened bacteriologically 6 times in a year. The contamination indices observed were lower within than outside the units, and lower in the SPF than in the conventional unit. Bacterial counts in rooms containing animals in the conventional and SPF units were very similar. In all of the areas investigated within the units, most of the samples revealed <2 colony forming units per cm2. In contrast, high degrees of bacteriological contamination were detected in the changing rooms after showering or washing before entry. Staphylococcus epidermidis was the dominant bacterial species isolated. The bacteriological spectrum did not vary between the areas surveyed.
Fistula channel from the ear to the frontal region in 2 guinea-pigs having streptococcal empyema of the middle and inner ear
Authors: Kunstýř I.
Published: June 2007

2 cases of a frontal fistula in guinea-pigs as a consequence of purulent streptococcal otitis interna and media are described and illustrated.
Seasonal and sexual influences on rabbit atropinesterase
Authors: Liebenberg S. P. , Linn J. M.
Published: June 2007

Atropinesterase was found in 61·17% of 6686 New Zealand White rabbits of both sexes studied over 2·5 years. Significantly more males possessed the enzyme, there was a significant difference in atropinesterase frequencies in males versus females in the winter and summer seasons, and a significant decrease in the frequency of atropinesterase-positive females during the winter.
Demyelination and wasting associated with polyomavirus infection in nude (nu/nu) mice
Authors: Sebesteny A. , Tilly Rita , Balkwill Frances , Trevan D.
Published: June 2007

Nude ( nu/nu) mice bearing human tumour heterografts were affected with posterior paralysis and wasting. There was demyelination and infection of the oligodendrocytes of the spinal cord with a papovavirus. Similar virus particles and inclusion bodies were found in the bronchial epithelium, which showed histopathological changes. Similar changes were shown by the epithelia of the renal pelvis, ureter and choroid plexus. The virus was found in a transplantable human tumour, and evidence of spread by contact was also obtained. Intracerebral injection of spinal cord suspension from infected mice resulted in virus infected cutaneous carcinomata, demyelination with virus particles in the oligodendrocytes and posterior paralysis with wasting in adult nude mice. The suspension injected intraperitoneally into newborn Syrian hamsters produced tumours similar to those produced by murine polyoma. No evidence of infection was found in mice from the colony of origin. The virus was identified as murine polyoma Wild Type A2.
A strain of Pasteurella multocida associated with infections in rabbit colonies
Authors: Mushin Rose , Schoenbaum M.
Published: June 2007

Pasteurella multocida was isolated from 4 conventional rabbit colonies. Amongst 51 isolates, 48 (94%) belonged to a group of strains with similar morphological, cultural, biochemical and antigenic characteristics; they were named for convenience Lo strains and gave rise to local or ascending infections. All Lo strains were found to be a new serotype, but 8 of them had additional antigenic factors characteristic of known serotypes.

The other 3 isolates (6%) were identified as serotype 3, known to have a wide host range: 2 strains were associated with septicaemia and haemotogenic spread, and 1 with snuffles.

Diagnostic agglutinating antibodies were present in the sera of adult rabbits. Maternal antibodies were in the sera of rabbits of 3 and 4 weeks old, but by the age of 8 weeks the titres had fallen to an undetectable level.
Enterotoxaemia involving Clostridium perfringens iota toxin in a hysterectomy-derived rabbit colony
Authors: Eaton P. , Fernie D. S.
Published: June 2007

During an explosive outbreak of fatal enteropathic disease involving Clostridium perfringens iota (i) toxin. a total of 183 deaths occurred in 18 weeks. The clinical signs and post-mortem findings are reported. Examinations for virus, Bacillus piliformis and coccidia were negative. Clostridium perfringens i toxin was detected in 22 of 27 animals examined (81·5%), but clostridia were not isolated. Various treatments wcre attempted. It is concluded that i toxin and the syndrome described are closely related.