Calculation of shift of avalanche transit time phase delay due tooptically injected carriers in indium phosphide avalanche diodes

A computer method for the calculation of the phase shift due to optically injected carriers in an InP avalanche transit time diode has been suggested using the numerically simulated negative resistance profiles in the depletion layer of the diode. The results show that the phase shift due to hole injection is larger than that due to electron injection which explains the pronounced effect of photogenerated hole leakage current in modulating the microwave properties of InP diodes     

Modified FSS response from two sided and closely coupled arrays

A demonstration is presented of a way in which an affected FSS response can be achieved using a two sided structure of dipole arrays sharing the same dielectric layer. Even with these simple elements the results produced resonances well below the grating lobe region, and consequently the instability of these with oblique angles of incidence (up to 75°) was less than 1%. The key to this work was the high coupling between the arrays that was achieved by a relative displacement     

Characterization of a diffusion-bonded Al-Mg alloy/SiC interface by high resolution and analytical electron microscopy

The interfacial structure of a diffusion-bonded Al-4.55 at. pct Mg/SiC interface was examined by conventional and high-resolution transmission electron microscopy. Formation of Mg₂Si, MgO, and Al₂MgO₄ was observed. The monoclinic Mg₂Si phase formed at the Al/SiC interface, while the oxides MgO and Al₂MgO₄ formed at the monoclinic Mg₂Si/Al interface. It is shown that the formation of these phases can be predicted using simple thermodynamic criteria such as the relative bond strengths between Al, Si, C, O, and Mg. In addition, precipitation of some equilibrium Al₈Mg₅ precipitate was also observed at the interface. The interfacial structure observed in the Al-Mg/SiC system is contrasted with that observed in the pure Al/SiC system.     

8-OH-DPAT induces a selective increase in protein intake in ageing overweight animals

We have examined the effects of a 5-HT1A receptor agonist (8-hydroxy-2-(di-n-propylamino)tetralin, 8-OH-DPAT) on food preference in ageing rats that had been given a 'palatable' meal 15 min before administration of the drug. Ageing rats consumed a greater amount of the 'palatable' pre-meal than the young rats. In young rats lipids were the predominant source of calories, but in old animals lipid and protein consumption was similar. Administration of 8-OH-DPAT resulted in an increase in total caloric intake in both groups. Concomitant with this there was a significant increase in protein intake in both groups, which was most important in ageing rats, where proteins became the predominant source of calories.     

Psychiatric disorders and homicide recidivism

There are no firm epidemiologic data concerning psychiatric disorders associated with homicide recidivism. The authors studied all homicide recidivists who were incarcerated in Finnish prisons or high-security hospitals and had committed their last offense during the 3-year period July 1, 1988-June 30, 1991. All recidivists (13 subjects) could be considered to suffer from either severe alcoholism combined with personality disorder (N = 11, 85%) or from schizophrenia (N = 2, 15%).     

Study of the beta -delayed neutron decay of 18N

The shortage of suitable liver donors for children has motivated the use of ABO-incompatible (ABO-I) grafts for transplantation in urgent situations. However, survival after ABO-I liver grafts has been reported at about 30% as compared with 80% in cases of ABO-identical or -compatible liver grafts. This difference has been attributed to antibody-mediated, hyperacute or chronic liver rejection, due to preformed ABO antibodies (alloantibodies). In this study, we report our results with ABO-I livers in children without alloantibodies at the time of transplantation. From January 1988 to June 1993, 143 OLT were performed in 122 children. Eight children received 8 ABO-I liver grafts. Of these, 7 patients were included in the study. All 7 were alloantibody free before OLT. Five children were spontaneously alloantibody free, while in 2 children, the plasma alloantibodies were eliminated before and after transplantation using intravenous infusion of specific blood group antigens of the donor blood group (soluble antigens). Immunosuppression consisted of a triple-drug treatment combining CsA, AZA, and steroids. The follow-up period was between 10 and 48 months. One child died from a surgical complication. Six children survived, but 1 died 10 months later from intestinal obstruction. There were no graft losses and no episodes of hyperacute or chronic rejection. The graft and patient survival rate was 71%. There was a 28% incidence of rejection, but all were mild (requiring steroid boluses only). Our results suggest that the absence of ABO alloantibodies at the time of and after transplantation can protect ABO-I liver grafts against antibody-mediated rejection, whether hyperacute or chronic, and that soluble antigens are effective in eliminating alloantibodies in children.     

Immunoscintigraphy of bone sarcomas--results in 5 patients

The feasibility of using the murine monoclonal antibody, TP-1, for clinical immunoscintigraphy was examined in a pilot study involving 5 patients with bone sarcomas. 131I-labelled F(ab')2 antibody fragments were injected in doses of 0.8-1.0 mg (90-130 MBq), and the accumulation of radioactivity was examined by scintigraphy, and assessed by direct measurements on biopsied tumour and normal tissue. One osteosarcoma patient had a primary tumour in the femur, whereas the other 4 had single lung metastases detected by other diagnostic methods. Immunoscintigraphy of the femoral primary was optimally visualised after 22 h. In 2 patients, the method failed to detect lung metastasis, in 1 of the cases possibly related to less than optimal methodological conditions. In 2 other patients, increased accumulation of radioactivity indicated one and three lung tumours, in addition to the single metastasis observed by X-ray and CT scanning, tumours that were later confirmed and removed surgically. The concentration of radioactivity in tumour and normal tissues 44-72 h after antibody injection could be measured in 4 patients. The tumour to blood ratios were in the range of 1.2-4.2, compared to 0.1-0.8 for various normal tissues. The results indicate that immunoscintigraphy with TP-1 antibody fragments have a potential for early detection of lung metastases in patients with bone sarcoma.     

Pathogenesis of Mycobacterium bovis infection in cattle

This paper reviews the pathogenesis of Mycobacterium bovis infection in cattle, focusing on aspects relating to the host rather than the organism. A broad concept of pathogenesis has been considered and information is presented on sources and routes of infection, as well as the immune responses and pathology. In addition, data is presented on the excretion of M. bovis from tuberculous cattle.