High-performance self-aligned SiGeC HBT with selectively grown Si/sub 1-x-y/Ge/sub x/C/sub y/ base by UHV/CVD

Si/sub 1-x-y/Ge/sub x/C/sub y/ selective epitaxial growth (SEG) was performed by cold-wall, ultrahigh-vacuum chemical vapor deposition, and the effects of incorporating C on the crystallinity of Si/sub 1-x-y/Ge/sub x/C/sub y/ layers and the performance of a self-aligned SiGeC heterojunction bipolar transistor (HBT) were evaluated. A Si/sub 1-x-y/Ge/sub x/C/sub y/ layer with good crystallinity was obtained by optimizing the growth conditions. Device performance was significantly improved by incorporating C, as a result of applying Si/sub 1-x-y/Ge/sub x/C/sub y/ SEG to form the base of a self-aligned HBT. Fluctuations in device performance were suppressed by alleviating the lattice strain. Furthermore, since the B out diffusion could be suppressed by incorporating C, the cutoff frequency was able to be increased with almost the same base resistance. A maximum oscillation frequency of 174 GHz and an emitter coupled logic gate-delay time of 5.65 ps were obtained at a C content of 0.4%, which shows promise for future ultrahigh-speed communication systems.     

Effects of radioactive fallout on the pregnant woman and the fetus

The levels of ⁹⁰Sr and ¹³⁷Cs in human placenta, fetus and diet were determined by radiochemical methods during the period from March 1966 to December 1968. The possible effects of these radionuclides on the pregnant woman and the fetus were discussed. The metabolic characteristics of both ⁹⁰Sr and ¹³⁷Cs were also discussed on the basis of estimates of discrimination factors and observed ratios of these radionuclides.

As a result of the analyses, the dose rate to the human placenta resulting from deposition of ⁹⁰Sr in the organ was estimated at about 0.003 mrem/month and that of ¹³⁷Cs at about 0.013 mrem/month. The dose rate to the total body resulting from the body burden of these radionuclides in the mother was estimated at about 0.012 mrem/ month. These values are much smaller than the monthly dose from ⁴⁰K normally existing in the body.

It was rather difficult to draw definitive conclusions concerning the possible correlation between the ⁹⁰Sr fallout and the annual changes of infant mortality rates in Japan.     

HLA class I and class II of the Nivkhi, an indigenous population carrying HTLV-I in Sakhalin, Far Eastern Russia

The Nivkhi are a native people isolated in the Nogliki region of Sakhalin, Far East Russia, where our group recently recognized human T-cell lymphoma virus type I (HTLV-I) infection. In order to trace the Nivkhi's ethnic background and the HTLV-I carriers, we investigated HLA class I and II allele types of 53 Nivkhi (including four HTLV-I carriers). Major HLA class I alleles of the Nivkhi were A*24, A*02, B*40, B*48, B*27, B*35 with allele frequencies similar to the Orochon, a native people isolated in Northeast China. Major Nivkhi class II alleles were DRB1*0901, DRB1*1401, DRB1*1201, DRB1*1106 with allele frequencies similar to the Ainu in Hokkaido, Japan, but dissimilar to other Asian Mongoloids, including the general Japanese population. The same HLA class I and II allele frequencies are found in both Nivkhi HTLV-I carriers and the background population. A dendrogram of HLA class I alleles showed that the Nivkhi were closely related to the Orochon and Yakut, and remotely related to the Japanese, Ainu and other Asian Mongoloids. Interestingly, the Nivkhi were intermediately related to the Amerindians (Inuit, Tlingit and Andeans), a relationship closer than to the Japanese and Asian Mongoloids. These results suggested the Nivkhi might be related to some genetic group of Northeast Asian Mongoloids like the Orochon and Yakut, being infected with HTLV-I in the distant past before diverging into the current major Mongoloid ethnic groups.     

Elastic basket switching

This paper proposes a new integrated switching system, ‘elastic basket switching’, for broadband and multimedia communications, including voice and high-speed data. In elastic basket switching (EBS), it is possible flexibly and efficiently to handle multimedia information by adaptively assigning communication resources according to communication requests and bandwidth of switched information. For continuous information, such as voice, EBS functions just as a circuit switching system, and for burst data it achieves high-efficiency bandwidth usage equivalent to a packet switching system by demand-assign type time-slot assignment. The detail of EBS and its application to a departmental system-orientated PBX are described. The traffic handling capability and details of the hardware structure are presented. The experimental system, including use of LSIs in the main parts of EBS is also described.     

Juxtaglomerular cell tumor without hypertension

The diagnosis of haematological malignancies has undergone major conceptual changes in the past decade. Accurate diagnosis now depends on a combination of morphological examination, cell marker studies, and molecular biological techniques. Specialist haematopathology diagnostic services are best provided in an integrated laboratory, able to carry out the full range of techniques and staffed by pathologists and scientists with expertise in the investigation of leukaemia and lymphoma.     

Photo-induced valence tautomerism in Co complexes

A number of photofunctional molecular compounds have been developed recently. Typical examples of these are phototunable valence tautomeric compounds, which are now attracting great attention. When the charge-transfer bands of some Co valence tautomeric compounds are excited at low temperature, metastable redox isomers can be created after irradiation. The lifetimes of the metastable states can be more than several hours. These transformations can involve changes in the magnetic properties of the compounds, as well as their color. Hence, these compounds can be regarded as novel photomagnetic materials. The photoresponsive behaviors of these valence tautomeric compounds are similar to those of spin-crossover complexes (light-induced excited spin-state trapping effects).     

67-GHz static frequency divider using 0.2-μm self-aligned SiGeHBTs

A 67-GHz 1/4 static frequency divider using 0.2-μm self-aligned selective-epitaxial-growth SiGe heterojunction bipolar transistors, with a 122-GHz cutoff frequency, a 163-GHz maximum oscillation frequency, and an average emitter coupled logic gate delay time of 5.65 ps, was developed. The pretracking master-slave toggle flip-flop (MS-TFF) of the divider increases the maximum operating frequency to about 15% higher than that of a conventional MS-TFF, yet the power consumption of the divider is 175 mW, which is 1/5 that of comparable dividers, at a supply voltage of -5.2 V     

A case of metastatic carcinoma to the retina]

The authors report a case of metastatic carcinoma to the retina. The patient was a 61-year-old man who had an operation for a well-differentiated adenocarcinoma of the rectum. Ophthalmoscopic examination disclosed a single, white, elevated mass lesion surrounded by serous retinal detachment located in the upper part of the macula of the right eye. A few retinal hemorrhages existed around the lesion. Fluorescein angiography revealed partially obscured retinal vessels due to compression by the tumor and arteriovenous anastomosis. Postmortem pathologic examination confirmed metastases to the brain, lung and retina. Microscopic examination showed a retinal lesion and tumor cells in the right eye. Tumor cells, similar to the carcinoma of the rectum, were present only in the neurosensory retina and did not invade the pigmented epithelium or choroid.