Cell density-dependent DNA fragmentation and its suppression by heparin in primary culture of adult rat hepatocytes

We show here that the internucleosomal DNA fragmentation, which is a biochemical hallmark of apoptosis, was induced in a cell density-dependent manner in primary culture of adult rat hepatocytes. This DNA fragmentation could be suppressed by a gene expression inhibitor, indicating the active nature of this process. Moreover, the viability changes in high and low cell density cultures showed a tendency corresponding with the incidence of the DNA fragmentation in them. These results suggest that in hepatocytes there may be a cell density-dependent apoptosis mechanism. In this report, we also show that heparin could suppress this DNA fragmentation with high specificity, and the cell death to some extent.     

The spatial distribution and spectral characteristics of field-induced electron emission sites on broad-area high voltage electrodes

Instrumental techniques are described for displaying (a) the spatial distribution of field emission sites on planar high voltage electrodes and (b) the emission current pattern within an individual site. Typically, emission ‘sites‘ are generally composed of three or more ‘sub-sites’ that become temporally unstable at current > 10^?7 A. The electron energy spectra of sub-sites are characteristically single peaked, whose half-widths (FWHM) initially vary linearly with applied field: from changes in spectral area with field, substantially linear sub-site F-N plots have been obtained having β values in the range 300–500.     

High-gain pseudomorphic InGaAs base ballistic hot-electron device

A high-gain ballistic hot-electron device is described. The GaAs-AlGaAs heterostructure device, with a 21-mm-thick pseudomorphic In _0.12Ga_0.88As base, had a current gain of 27 at 77 K and 41 at 4.2 K. As characteristically seen in ballistic devices, transfer into the L valley limited the maximum gain. The Γ-L valley separation in the strained In_0.12Ga_0.88As was estimated to be about 380 meV     

Dielectric reliability of stacked Al2O3–HfO2 MIS capacitors with cylinder type for improving DRAM data retention characteristics

Dielectric reliability in Al₂O₃(2–3.1nm)–HfO₂(3nm) stack capacitor with Metal–Insulator–Si(MIS) structure is investigated in this paper. We propose an optimized capacitor process through the Time–Dependent Dielectric Breakdown (TDDB) data under various process conditions. Furthermore, due to asymmetric current at both negative and positive voltage stress polarities, we show different lifetime extrapolation by a fluence–driven model. As a result, the maximum allowed operating voltage is projected to be 1.7V (failure rate 10ppm during 10year @ 85°C) for Data “0” retention lifetime.     

W-band divide-by-3 frequency divider using 0.1 /spl mu/m InAlAs/InGaAs metamorphic HEMT technology

A W-band divide-by-3 frequency divider with wide bandwidth and low power dissipation is presented using harmonic injection-locking technique. A cascode FET is employed for a self-oscillating second-harmonic mixer which is injection-locked by third-harmonic input to obtain the division order of three. The fabricated frequency divider using 0.1 /spl mu/m GaAs metamorphic HEMT technology shows superior performance such as large bandwidth of 6.1 GHz around 83.1 GHz (7.3%) under small DC power consumption of 12 mW.     

Using classification techniques for informal requirements in the requirements analysis-supporting system

In order to efficiently develop large-scale and complicated software, it is important for system engineers to correctly understand users’ requirements. Most requirements in large-scale projects are collected from various stakeholders located in various regions, and they are generally written in natural language. Therefore, the initial collected requirements must be classified into various topics prior to analysis phases in order to be usable as input in several requirements analysis methods. If this classification process is manually done by analysts, it becomes a time-consuming task. To solve this problem, we propose a new bootstrapping method which can automatically classify requirements sentences into each topic category using only topic words as the representative of the analysts’ views. The proposed method is verified through experiments using two requirements data sets: one written in English and the other in Korean. The significant performances were achieved in the experiments: the 84.28 and 87.91 F1 scores for the English and Korean data sets, respectively. As a result, the proposed method can provide an effective function for an Internet-based requirements analysis-supporting system so as to efficiently gather and analyze requirements from various and distributed stakeholders by using the Internet.     

Persistent GAD 65 antibodies in longstanding IDDM are not associated with residual beta-cell function, neuropathy or HLA-DR status

Persistent humoral autoimmunity to the enzyme glutamic acid decarboxylase (GAD) has been described in a substantial proportion of patients with insulin-dependent diabetes mellitus (IDDM) of long duration. The source of the stimulus for this autoimmune reactivity is still unknown. Because the GAD 65 isoform is mainly expressed in pancreatic beta-cells and in the nervous system we investigated in the present study of the largest number of well characterized patients with longstanding IDDM (n = 105; median duration: 21 years; range: 10-46 years) the presence of autoantibodies to GAD 65 and their relationship to a residual C-peptide response or peripheral and autonomic neuropathy. Additionally we studied the HLA-DR status relative to GAD 65 antibodies in 86 out of the 105 individuals. One hundred healthy control subjects and 100 recent onset IDDM patients were also studied for GAD 65 antibodies. GAD 65 antibodies were detected in a radioligand-binding-assay with recombinant human GAD 65 and were present in 32% of the long-term diabetic patients, 82% of the recent onset IDDM patients and in 3% of the healthy control subjects. A preserved C-peptide response to i.v. glucagon (Hendriksen criteria) was observed in 23% of the long-term IDDM patients. Autonomic neuropathy and peripheral neuropathy was identified using criteria based on both symptoms and formal testing giving a frequency of 67% vs 79%. The HLA specific DR 4/X was observed in 47% and HLA-DR 3/X in 22% of the long-term IDDM patients. Patients who were heterozygous for DR3/DR4 were found in 23% of the cases. GAD 65 antibodies were significantly less frequent in the long-term IDDM patients compared to recent onset IDDM (p < 0.001), and diabetes duration showed a significant negative correlation with GAD 65 antibody index levels (r = 0.22, p < 0.01). Interestingly, GAD 65 antibodies were not significantly correlated either with residual beta-cell function or neuropathy and no particular HLA-DR status was associated with persistent GAD 65 antibodies. In conclusion neither residual beta-cell function nor diabetic neuropathy or a certain HLA-DR specificity are exclusively associated with persistent autoimmunity directed to GAD 65 in longstanding IDDM. The stimulus for the persistent humoral immune response and its significance for the disease process and its complications remain to be established.