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A two dimensional model of the transient natural convection in a freezer is studied numerically by finite volume approach. The temperatures of the freezer outside surfaces and the evaporator vary in specified manners, which were taken from an experimental work. The fluid in the freezer is of the Bousinnesq type and the flow is assumed laminar. The transient heat conduction in the insulating layers and the temperature and velocity fields of the fluid are solved conjugately. The radiation heat transfer between the freezer inner surfaces is taken into account by using the additional source term method. The distributions of the local Nusselt number along the upper and lower surfaces of the evaporator and their average values in the period of periodically unsteady operation are calculated. Comparisons are made between the results with and without consideration of inner surface radiative heat transfer. It is found that the radiative heat transfer between the inner surfaces has a profound effect on the evaporator heat transfer characteristics.

Penile lymphoma is extremely rare and secondary involvement of the penis by lymphoma may be due to retrograde spread or to direct extension from neighbouring organ. The appearance of penile lymphoma varies and can be mistaken for other soft tissue tumours. We report on a case with malignant lymphoma of the penis. MRI findings revealed soft-tissue mass of homogeneous isointensity around the middle to distal part of penis on T(1) weighted imaging and T(2) weighted imaging. It was well encapsulated, minimally enhanced and distinct from corpus cavernosum and corpus spongiosum.

125I-labeIed specific immune globulin was used in a 2-step procedure to detect hepatitis B virus-associated antigen in blood serum or plasma. In step 1, undiluted sample was incubated overnight in polypropylene tubes coated with hyperimmune guinea pig antiserum. The serum sample was then removed and specific 125I-antibody was added and incubated for a period of 90 min. The presence of antigen in the original sample was then reflected by the count rate of the tube after the unreacted labeled antibody was removed. A typical dose response curve was observed for antigen in the concentration ranges of 0.005–0.32 μg/ml. Replicate analyses of normal sera and a low-titer positive sera revealed method variations which were distributed between ± 5 standard deviations from the replicate mean values. The radioimmunoassay was 500–1,000 times as sensitive as complement fixation for ad-subtype antigens. For ay-subtype antigens, the method was 128–512 times as sensitive as complement fixation. Assay values of 4,500 blood donor sera had a typical distribution, with most counts falling between +3 and –3 standard deviations relative to a negative control serum. However, 6% of the samples gave a count rate greater than 3 standard deviations from the negative control mean, and about 3.5% gave a count rate greater than 5 standard deviations above the negative control mean. The increased sensitivity of the method resulted in the detection of more positive sera in a variety of donor groups than other immunological methods. In two volunteer donor groups, 1.4 and 1.9% of the samples were positive. In two analyses of commercial paid donors, one group was 4.6% positive and one was 5.5% positive.

(1) Nerve-ending particles isolated from crude mitochondrial preparations from rat brain by discontinuous Ficoll density gradient ultracentrifugation were shown to possess a Mg2+ and energy-dependent transport system for Na+. (2) Ouabain or iodoacetate plus cyanide exerted an inhibitory effect on the outflux but not the influx of Na+. (3) When K+ was added to a medium containing particles loaded with Na+ (22Na), an immediate release of Na+ from these particles was observed; this suggests the existence of a Na+-K+ exchange transport system. (4) The K+ effect was inhibited by 10(-4) M-ouabain only at low (about 3.3 mM), but not at high (20 mM), K+ concentrations. (5) The uptake and release of Na+ by the nerve-ending particles were found to be temperature-dependent. (6) Only nerve-ending particles with intact synaptosomal membranes were found to transport Na+ actively.

A two-step direct radioimmune test was used to detect hepatitis B virus associated antigen in human serum or plasma. The procedure involved the use of polypropylene tubes coated with hyperimmune guinea pig serum, and 125I-labeled specific hepatitis B virus antigen immune globulin. The technique appeared to be more sensitive than other immunologic assays, including indirect radioimmune methods based on competition of unlabeled antigen with 125I-labeled antigen. Various blood donor populations were tested for antigen by the direct radioimmune test, by complement fixation, agar gel diffusion and counterimmunoelectrophoresis. The increased sensitivity of the radioimmune procedure resulted in the detection of about 3 to 8 times as many positive sera as the above three immunologic methods. The percentages of positive sera by radioimmune assay were: about 1% in volunteer blood donors, about 2% in commercial blood donors and about 40% in hepatitis-implicated patients.

Four kinds of particles were reconstituted with RNA and protein from the genetically unrelated bacteriophages Qbeta and MS2, namely, two homologous and two heterologous, with respect to RNA and protein. However, once Qbeta RNA (or MS2 RNA) reacted with a few molecules of either Qbeta or MS2 protein to form a nucleoprotein complex (initiation complex), it formed a phagelike particle only with subsequent addition of the same protein.

PLASMA of hepatitis B antigen (HBsAg) carriers consists mostly of spherical particles of diameter 20 nm, together with a much smaller number of filamentous structures with the same diameter. In addition, larger spherical particles, 42 nm in diameter with a 28 nm core, first described by Dane et al.1, are routinely found in crude plasma or purified preparations of HBsAg. Dane particles also contain a primed DNA polymerase activity2 capable,of synthesising new DNA. Robinson et al.2 examined DNA from Dane particles by electron microscopy and found open, double-stranded circular configurations approximately 0.78 µm long. We have examined DNA isolated from Dane particles directly and also after formation of radioactive products by the endogenous DNA polymerase reaction. The DNA structures appeared in electron micrographs as double-stranded linear strands and closed circles, with examples of completely and partially open circles, and circles with attached linear segments in different lengths. The open circles with attached linear segments are suggestive of a replicative form, and this is consistent with a rolling circle model4 for replication. This model for replication is strengthened by the comparison of the types of DNA found in particles before and after reaction of the polymerase. The number of rolling circles and the length of the tails were greatly increased after DNA synthesis. This type of replication has not been reported for animal viruses.

The ideal age for surgery for muscular torticollis, the complications and results of open sternomastoid tenotomy were investigated in 60 patients operated on at different age-groups. Under the age of 1, tethering of the scar to the deeper structures was common and was mainly responsible for the lower percentage of good results (42.1 per cent). In the age-group 1 to 4 years, satisfactory correction of facial asymmetry, head and tilt and limitation of neck movements, was achieved with overall 66.7 per cent good results. However, in patients above the age of 5, not only was the correction of the secondary deformities uncertain but the late complications like loss of sternomastoid column, disfiguring scar and presence of lateral bands were more common. Only 33.3 per cent had good results in the 5 to 8 year age-group and none in the above 9 years age-group. The best time for surgery in muscular torticollis is in the patient between 1 and 4 years of age.

We compared the radioimmunoassay (RIA) and counterimmunoelectrophoretic (CIE) methods in detecting hepatitis B antigen (HBsAG) in 407 acute and 336 convalescent sera of adults with viral hepatitis. The CIE method demonstrated that 41% of acute and 28% of 14-to 17-day serum specimens were HBsAg-positive. The RIA method demonstrated seropositivity in 60% of acute and 56% of convalescent specimens (P less than .001). Eighty-four percent of coded specimens initially positive for HBsAg by RIA were found to have subtype antigenic determinants d or y; 92% of the HBsAg-negative controls were negative for subtype antigens, confirming the specificity of the RIA test. RIA subtyping data corroborated earlier work with immunodiffusion techniques.

Radioimmunnoassay was used to determine the serologic subspecificities of 85 blood donor serums positive for hepatitis B virus-associated antigen. There was complete agreement with results obtained by immunoprecipitatiotn of 43 serums. The remaining 42 serums were negative by immunoprecipitation but followed type-specific immunology by radioimmunoassay, and this served as a validation for authentic hepatitis B virus antigen.

PLASMA of hepatitis B patients and antigen carriers contains a high concentration of spherical and filamentous particles (HBsAg), about 20 nm in diameter and without evidence of nucleic acid. There are also a relatively few spherical particles, 42 nm in diameter with a 28 nm core, first described by Dane et al.1. Dane particles contain a unique deoxyribonucleic acid2 and a DNA polymerase3 capable of synthesising DNA so they are considered to be a leading candidate for a human hepatitis B virus. Double stranded DNA of unique base composition has been isolated from the naked intranuclear particle of hepatocytes of human hepatitis liver5. The large quantity of HBsAg, resembling defective virus, in the plasma of carriers prompted us to investigate a possibility that there may exist free or ‘unassembled’ DNA corresponding to the empty particles in these plasmas. The presence of both free DNA and empty particles could result from faulty assembly of a virus. We report here the presence of free DNA in HBsAg positive plasma and this free DNA showed homology with radiolabelled Dane particle DNA by molecular hybridisation.

Hepatitis B surface antigen (HBsAg) consists of three morphological forms identified by negative stain electron microscopy as spherical and rodshaped particles of approximately 22 nm diameter and double-shelled Dane particles of 42 nm diameter (Fig. 1). Dane particles contain DNA and are believed to represent the Hepatitis B virion while the smaller forms of HBsAg are thought to correspond to excess viral lipoprotein antigenically related to the surface of Dane particles. Electron microscopic studies of HBsAg in human blood plasma have always been carried out using negative staining techniques and Dane particles reportedly account for only a very small portion of HBsAg particles found in plasma. In the present study we demonstrate the usefullness of a previously devised thin-section virus particle counting technique (1) for detecting and enumerating Dane particles in either whole or partially purified blood plasma.