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Diffusible iodine-based contrast-enhanced computed tomography (diceCT) has emerged as a viable tool for discriminating soft tissues in serial CT slices, which can then be used for three-dimensional analysis. This technique has some potential to supplant histology as a tool for identification of body tissues. Here, we studied the head of an adult fruit bat (Cynopterus sphinx) and a late fetal vampire bat (Desmodus rotundus) using diceCT and µCT. Subsequently, we decalcified, serially sectioned and stained the same heads. The two CT volumes were rotated so that the sectional plane of the slice series closely matched that of histological sections, yielding the ideal opportunity to relate CT observations to corresponding histology. Olfactory epithelium is typically thicker, on average, than respiratory epithelium in both bats. Thus, one investigator (SK), blind to the histological sections, examined the diceCT slice series for both bats and annotated changes in thickness of epithelium on the first ethmoturbinal (ET I), the roof of the nasal fossa, and the nasal septum. A second trial was conducted with an added criterion: radioopacity of the lamina propria as an indicator of Bowman’s glands. Then, a second investigator (TS) annotated images of matching histological sections based on microscopic observation of epithelial type, and transferred these annotations to matching CT slices. Measurements of slices annotated according to changes in epithelial thickness alone closely track measurements of slices based on histologically-informed annotations; matching histological sections confirm blind annotations were effective based on epithelial thickness alone, except for a patch of unusually thick non-OE, mistaken for OE in one of the specimens. When characteristics of the lamina propria were added in the second trial, the blind annotations excluded the thick non-OE. Moreover, in the fetal bat the use of evidence for Bowman’s glands improved detection of olfactory mucosa, perhaps because the epithelium itself was thin enough at its margins to escape detection. We conclude that diceCT can by itself be highly effective in identifying distribution of OE, especially where observations are confirmed by histology from at least one specimen of the species. Our findings also establish that iodine staining, followed by stain removal, does not interfere with subsequent histological staining of the same specimen.

Heterologous expression of the human T-cell lymphotropic virus type 1 (HTLV-1) envelope surface glycoprotein (gp46) in a vaccinia virus/T7 polymerase system resulted in the production of authentic recombinant gp46. Five differentially glycosylated forms of the surface envelope protein were produced by this mammalian system, as demonstrated by tunicamycin inhibition of N-glycosylation and N-glycan removal with endoglycosidase H and glycopeptidase F. These studies revealed that all four potential N-glycosylation sites in gp46 were used for oligosaccharide modification and that the oligosaccharides were mannose-rich and/or hybrid in composition. Conformational integrity of the recombinant HTLV-1 envelope protein was determined by the ability to bind to various HTLV-1-infected human sera and a panel of conformational-dependent human monoclonal antibodies under nondenaturing conditions. Furthermore, this recombinant gp46 was recognized by a series of HTLV-2-infected human sera and sera from a Pan paniscus chimpanzee infected with the distantly related simian T-cell lymphotropic virus STLVpan-p. Maintenance of highly conserved conformational epitopes in the recombinant HTLV-1 envelope protein structure suggests that it may serve as a useful diagnostic reagent and an effective vaccine candidate.

We have compared the immunoglobulin isotype and IgG subclass and the titre of neutralizing antibody responses to the human T cell lymphotropic virus type I (HTLV-I) between a group of asymptomatic HTLV-I infected individuals and a group with the neurological disease HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP). A western blot titration assay and an envelope peptide ELISA were used to determine the presence and titre of isotype and IgG subclass responses to the gag p19 and p24 proteins and to the envelope protein. Significant increases were observed in the number of individuals seropositive for a particular isotype and IgG subclass in the HAM/TSP group versus the asymptomatic group particularly for IgM and IgE and to a lesser extent, IgA. The predominant IgG subclasses to the HTLV-I p19, p24 and envelope proteins were IgG1 and IgG3. This finding was also observed in the titres of the antibody responses to these HTLV-I proteins. The HAM/TSP group also exhibited significantly higher neutralizing antibody titres than the asymptomatic group. This evidence suggests that some form of chronic immune stimulation might be involved in the immunopathogenesis of HAM/TSP. In addition, by following the Western blot titre to the IgM and IgE isotypes in particular, it may be possible to identify asymptomatic individuals progressing to HAM/TSP.

Recent epidemiology studies have demonstrated the presence of HTLV-I and its close relative, HTLV-II in several aboriginal populations in North, Central and South America but not in Canadian Indian populations. HTLV-II appears to be more prevalent than HTLV-I in aboriginal populations of the Americas. Recently several clinical cases of HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) and a case of adult T-cell leukemia (ATL) have been identified in British Columbian Indians. This data suggests that a new endemic area of HTLV-I infection may be present within British Columbian Indian population. However, it has recently been shown that HTLV-II may also be associated with a neurological disease similar to HAM/TSP.The purpose of the work reported here was to demonstrate whether HTLV-I, HTLV-II or both were responsible for the diseases seen in the British Columbian Indians.In this study serological and gene amplification techniques were used to determine whether HTLV-I or HTLV-II was present in four families and three unrelated individuals all from different bands of aboriginal Native Indians in British Columbia. In each family, one member had an HTLV-associated disease, three cases of HAM/TSP and one case of ATL. Of the three individual aboriginal natives unrelated to the four families, two had HAM/TSP while the third was asymptomatic for HTLV-associated diseases.This study demonstrated the presence of HTLV-I in the aboriginal Indians with disease and in some of their family members. HTLV-II was not detected in any of the British Columbian Indians tested in this study.These British Columbian Indians represent the first Canadian aboriginal Indians with HTLV-I infection and associated diseases. Furthermore, the British Columbian Indian population may represent a previously unrecognized endemic population of HTLV-I infection.

We fabricated bismuth (Bi) nanowires with low energy electron beam lithography using silver (Ag) nanocrystal shadowmasks and a subsequent chlorine reactive ion etching. Submicron-size metal contacts on the single Bi nanowire were successfully prepared by in situ focused ion beam metal deposition for transport measurements. The temperature dependent resistance measurements on the 50 nm wide Bi nanowires showed that the resistance increased with decreasing temperature, which is characteristic of semiconductors and insulators.

Human T-lymphotropic virus type 1 (HTLV-1) infection has been discovered recently in people of Amerindian descent living in coastal areas of British Columbia, Canada. DNA sequencing combined with phylogenetic analysis and restriction fragment length polymorphism (RFLP) typing of HTLV-1 strains recovered from these British Columbia Indians (BCI) was conducted. Sequence-based phylogenetic trees distributed the BCI isolates among the Japanese subcluster (subcluster B) and the geographically widely distributed subcluster (subcluster A) of the large HTLV-1 cosmopolitan cluster. Long terminal repeat (LTR) RFLP typing revealed three distinct, equally frequent LTR cleavage patterns, two of which were of previously recognized Japanese and widely dispersed cosmopolitan types. A third, new cleavage pattern was detected which may have arisen by recombination between two other HTLV-1 genotypes. Our results suggest multiple origins for HTLV-1 in BCI, which are equally consistent with (i) a cluster of recent sporadic infections, (ii) ancient endemic vertical transmission through Amerindian lineages, or (iii) both.

The entire envelope gene of human T cell leukaemia virus type I (HTLV-I) has been successfully expressed in a baculovirus non-fusion vector system. The HTLV-I envelope protein accumulated within the insect cells as inclusion bodies which allowed efficient recovery of the recombinant protein. In an attempt to study the role of the HTLV-I envelope glycoprotein as an immunogenic target, mice were immunized with the envelope protein inclusion bodies (env-I.B.) in the presence or absence of an adjuvant. Antibodies of broad specificity were produced against the HTLV-I envelope protein in the presence or absence of an adjuvant as detected by Western blotting, radioimmunoprecipitation and peptide ELISA. Neutralizing antibody was detected when env-I.B. immunizations were carried out in the presence of high doses of a new adjuvant composed of a mycobacterial cell wall extract. In a combined immunization regimen, env-I.B. were found to enhance and broaden the antibody response to the HTLV-I envelope glycoprotein, following priming with various recombinant vaccinia virus (RVV) constructs expressing either the entire native HTLV-I envelope (gp46 and gp21) or just the surface envelope protein (gp46). Increased titres of neutralizing antibodies were observed following priming with the RVV expressing gp46 only. Results indicate that immunization regimens that involve priming with RVV expressing HTLV-I envelope followed by boosting with recombinant baculoviral HTLV-I envelope might be useful in eliciting protective immune responses in vivo.

Recombinant vaccinia viruses (RVV) designated RVV El, RVV E2, and RVV E3, were constructed to express three different versions of the human T cell leukemia virus type I (HTLV-I) envelope proteins to determine which configuration elicits an optimal antibody response. RVV E1 expressed the native HTLV-I envelope proteins gp46 (surface protein) and gp21 (transmembrane protein), while RVV E2 expressed the envelope precursor with the proteolytic cleavage site deleted. The RVV E3 construct expressed only the external surface glycoprotein, gp46. Radioimmunoprecipitation and FACS analysis confirmed that the appropriate envelope proteins were expressed by RVV El-, E2-, and E3-infected cells. Immunization studies were carried out using Balb/c, A/1, and C57BU6 strains of mice. Balb/c mice responded poorly to immunization with all of the three RVV constructs. C57BU6 mice produced neutralizing antibodies in response to immunization with all three constructs, whereas A/J mice developed neutralizing antibodies only when immunized with the RVV E1s construct. The results indicate that the humoral immune responses depend on the form of HTLV-I envelope proteins expressed by each RVV.

It is shown that a pinch resistor can be used to predict the neutron induced gain degradation of a related bipolar transistor. The experimental data indicate that the prediction accuracy can be at least as good as that obtained using the VBE(ON) measurement with a breakout transistor. Thus, the pinch resistor provides a simple DC test element which can be very effective in implementing a 100% electrical screening technique for the neutron hardness assurance of bipolar integrated circuits.

The relationships of the electrical properties of irradiated MOS structures to processed-induced surface defects have been investigated. It has been found that the radiation-induced perturbations in oxide space-charge and interface states relate directly to the density of oxidation-induced stacking faults and edge dislocations. The density of such surface defects depends on both the structural properties of the starting silicon and the fabrication procedures. Oxidation-induced stacking faults are strongly related to the oxidation conditions, such as temperature, time, and ambiance. High-frequency CV, quasi-static CV, and ac conductance techniques were used to determine the interface state densities and flat-band voltage distributions. It has been found that, in addition to interface states, exposure to ionizing radiation causes gross non-uniformities in trapped positive space-charge. Using secondary ion mass spectrometry (SIMS) on an MOS sample possessing a high density of stacking faults, it has been shown that positive charge-species drift to the SiO2/Si interface and form clusters in a random fashion similar to that of the defects delineated by differential etching. Based on the known relationship of surface generation lifetime on surface defects pre-irradiation lifetime has been demonstrated as an effective electrical parameter for the prediction of the total-dose radiation sensitivity of MOS devices.

Preparation de radicaux halogenoalkyles gazeux par photolyse d'iodohalogenoalcanes dans des reacteurs en pyrexe contenant des halogenures de Hg(I). La scission de la liaison C-I, donne un halogenure de Hg(II) et un radical qui reagit sur une surface d'energie electronique a l'etat fondamental

Several versions of the 1802 CMOS microprocessor were subjected to Co-60 irradiations. Total dose data is provided for production line parts from two vendors, a specially processed radiation hard lot, and one developmental SOS unit. The increase in total dose failure level from 1 x 104 to 5 x 105 rads(Si) for the specially processed Parts proves the feasibility of hardening the Si-gate LSI technology used for the 1802.

Transient nuclear radiation responses of integrated circuits can be simulated by irradiating the backside of the silicon die with a pulsed infrared laser. This technique facilitates the implementation of an effective, low cost, nondestructive, 100 percent transient radiation screen at wafer probe. Analytic predictions are shown to correlate closely with experimental results on an operational amplifier and its test cell components.

A long-term transient response mechanism has been discovered in certain GaAs FETs and FET logic circuits exposed to low level (~ 100 rad) ionizing radiation pulses. Recovery times ranging from 1 to 70 seconds have been measured following room temperature exposures. Charge trapping within the semiinsulating GaAs substrate appears to be a mechanism responsible for the observed behavior. Experiments conducted between 0° and 200°C have identified an acceptor level characterized by an activation energy in the 0.7 to 0.8 eV range.

The results of an effort to total-dose radiation harden N-channel static random-access-memories are described. Both an aluminum-gate and a silicon-gate process were hardened to a level greater than 104 rads(Si) on a semiconductor memory vendor's production line. The aluminum-gate RAMs have been found to operate to well above 105 rads(Si) at low dose rates, suggesting their suitability for space applications.

The long-term transient radiation response in ion implanted GaAs FETs induced by flash x-ray or electron pulses has been reduced by the incorporation of a deep buried p-layer beneath the active n-layer. Reductions in the change in drain current of up to two orders of magnitude were measured in FETs with the buried p-layer compared to FETs with only an n-implanted channel following a 100 rad x-ray pulse. This improvement in radiation tolerance is attributed to shielding of the active n-layer by the conducting p-layer from the effects of radiation induced trapped substrate charge.

The background to many of the current industry approaches to electrical testing of LSI devices is presented along with modifications to obtain the radiation responses of the devices. The results of several experiments conducted on CMOS RAMs using these approaches are presented. Although the CMOS technology was used in the experimental work, the basic technique is applicable to other technologies.

Flash x‐ray measurements have been made on GaAs metal semiconductor field effect transistor structures fabricated in both Cr‐doped and undoped semi‐insulating substrate material in order to characterize the levels responsible for long term transients in these devices. Prominent electron and hole traps with activation energies in the 0.76–0.90‐eV range have been identified. The main electron trap, which is present in both Cr‐doped and undoped substrates, appears to be primarily responsible for the observed transient response. However, traps related to Cr‐doping also contribute to the transient behavior.

Complete radiation sensitivity assessments of integrated circuits can now be performed at the wafer level using a new system, the Hardness Assurance Wafer Probe, HAWP. This system utilizes a pulsed Nd: YAG infrared laser impinging on the backside of the wafer to evaluate the transient behavior of the circuits. A low energy X ray source collimated to a single die site actually performs total dose irradiations. Finally, special electrical measurements are used to enable a prediction of the neutron sensitivity of bipolar devices. The HAWP System is described and correlations of wafer probe results to conventional radiation tests for a digital part type are provided.

The modulus-squared z-transform is introduced as a valuable aid in the evaluation of mean-squares in discrete-continuous systems. A short table of the transform is included and an example chosen to illustrate its application.

The torques of superconducting lead tori immersed in various uniform magnetic fields are calculated as a function of angular position and compared to measured values. The calculations, based on ideal superconducting behavior, are found to agree with experiment for the closed torus if persistent current decrease due to critical surface fields is taken into account. The recognition of trapped flux phenomena is needed to explain measured results for the open torus when it has been cooled in a nonzero field or when a magnetic transition to superconductivity has been made. The analytic model utilizes magnetic moments for a torus in an axial and in a perpendicular field, both having been calculated rigorously elsewhere. In addition, methods of obtaining approximations to these moments are presented because of their possible application to more general toroidal bodies. The total magnetic moment (and thus the torque) for arbitrary angular position is obtained by superposition, a result not heretofore available.

The radiation dose dependence of the energy profile of the interface state density, NFS(E), has been monitored for the first time by using quasistatic MOS C-V techniques. The surprising result is that the radiation-induced increases in the interface state density are proportional to the pre-irradiation density regardless of the energy position in the band gap (away from the band edges) and in spite of the differences in the nature of the pre-and post-irradiation interface states. Both undoped and aluminum-implanted silicon dioxide films were used in the MOS devices investigated in this effort. Also, the dose dependence of the capture crosssection for carriers, ?, has been determined for the first time by combining quasistatic MOS capacitance measurements with gate-controlled IEBO measurements. Initial cross section values were consistent with those determined by different techniques, ~6×10-16 cm2. Contrary to the results that have been reported by other workers, ? was found to be relatively constant with respect to changes in NFS. Consequently, the radiation-induced rise in the surface recombination velocity is interpreted as being primarily due to an increase in NFS.

The paper describes a numerical method of implementing Chang's statistical design theory for discrete-continuous systems. The method makes extensive use of machine computation for the derivation of the optimum parameter values of the discrete controller and has the main advantage that a quantitative measure of parameter sensitivity is given. The concept of parameter redundancy, whereby a class of sub-optimum systems may be synthesized, is introduced. These systems are only slightly inferior in performance compared with the direct Chang optimum system but have a considerably simplified control configuration.

Additional process controls which have been implemented by semiconductor manufacturers in order to produce low threshold voltage CMOS integrated circuits are shown to significantly improve the radiation hardness of such devices. In particular, this improvement is directly correlated with reduced concentrations of the sodium impurity which results in smaller threshold voltage shifts for the p-channel (negatively biased) transistors. Further, it has been shown that n-channel devices can be hardened by the technique of ion implantation on production line integrated circuits. Thus, digital CMOS devices hard to greater than a Mrad(Si) have been realized.

The amplitude of long term, pulse-radiation-induced transients in ion implanted GaAs FET's has been reduced by up to two orders of magnitude by the addition of a deep buried p-layer beneath the active n-layer. The p-layer was formed by ion implantation of Be to depth of 0.8 µm below the Si implanted n-active channel. Backgating was also greatly reduced as indicated by a much smaller amplitude transient response following application of a positive gate pulse and by the absence of light sensitivity and looping in the current/ voltage (I-V) characteristics.

Two types of devices representative of very-largescale-integration, 64k dynamic RAMs and 68000 microprocessors, have been studied in a total dose ionizing radiation environment. Both types of parts show an improved hardness compared to earlier test results for large-scale-integrated dynamic RAMs and microprocessors. This indicates that the previously developed downward trend of radiation hardness versus circuit complexity may not continue to prevail.

The ratio of proteins and carbohydrates in the adult diet of Anthonomus grandis Boheman was varied to study its effect on the initiation of diapause. Removal of germinated cottonseed puree from the standard diet greatly increased the incidence of diapause, but this effect was offset partially by increasing the level of protein and decreasing the level of sucrose. Similarly, a reduction of protein and an increase in sucrose caused greater numbers of insects to enter diapause. We were not able to extract the component (s) of germinated cottonseed that prevent initiation of diapause with chloroform, acetone, water, and dilute NaOH, in succession. A cottonseed flour or the alkali-soluble protein of that flour was equal to or better than germinated cottonseed in preventing the initiation of diapause.

Summary and ConclusionsThree mercurial diuretics, Thiomerin, Mercuzanthin and Mer-cuhydrin have been compared with respect to the tissue reaction which they produce. Thiom-erin was tolerated by mice on subcutaneous injection without exhibiting gross pathology while Mercuzanthin and Mercuhydrin gave rise to necrosis of the skin under the same conditions. After intramuscular injection in rats all three drugs gave an early inflammatory response characterized by the appearance of a polymorphonuclear exudate. In the case of Thiomerin this exudate was entirely resorbed without evidence of residual damage. After injection of Mercuzanthin, or Mercuhydrin, however, the irreversible nature of the response was indicated by marked fibroblastic proliferation.These results would seem to furnish an adequate experimental basis for the clinical use of Thiomerin by subcutaneous injection.The authors wish to thank the Misses Florence Katine and Josephine Brosseau for able technical assistance.