Notes: A compact 2.45 GHz ECR ion source has been developed at National Institute of Radiological Sciences (NIRS). The source was designed to provide doubly charged carbon ions, aiming at easy maintenance of the source. A set of permanent magnets was adopted to realize a minimum B structure. In pulse operation with a duty factor of 5%, the beam performance was measured with He, CO2, CH4, and N2 gases. With CO2 gas, analyzed beam currents are 160 and 15 eμA for C+ and C2+, respectively. Through the measurement of the microwave amplitude in the plasma chamber, it was found that the microwave power was not transmitted into the plasma chamber efficiently. © 1996 American Institute of Physics.

Notes: The intensity noise of strained InxGa1−xAs/InP multiple quantum well (MQW) lasers is measured for three types of strain: tensile strain (x=0.48), no strain (x=0.53), and compressive strain (x=0.65). From a comparison between the measured noise power spectral density and the theoretical one, the resonance frequency and the carrier damping factor of each type of lasers are calculated. Although compressive strained MQW lasers show abot 10% increase in resonance frequency compared to those of tensile strained and unstrained lasers, this increase is smaller than theoretically predicted. Most important, all three types of MQW lasers show about two to three times higher nonlinear gain saturation and lower maximum bandwidth than conventional double-heterostructure lasers. A solution to reduce this high damping is also discussed.

Notes: Carrier confinement performance by multiple quantum barriers (MQB) is demonstrated in 1.55 μm strained GaInAs/AlGaInAs multiple quantum well (MQW) lasers grown by molecular beam epitaxy. The strained MQW lasers with MQB at p-side optical confinement layer show larger characteristic temperature and slope efficiency at high temperature than those without MQB. It is also shown that the MQW lasers with MQB have less spontaneous emission from the optical confinement layer than the lasers without MQB. As another important result, it is demonstrated for the first time that the MQW lasers with MQB have less dependency of the K factor on the temperature than the lasers without MQB. These results further verify the effective carrier confinement performance of GaInAs/AlInAs MQB structure. © 1995 American Institute of Physics.

Notes: We fabricated a GaInP/AlGaInP visible laser with a real-index guide structure by one-step metalorganic vapor phase epitaxy using simultaneous impurity doping. We achieved an effective self-aligned current-confinement structure in the AlGaInP cladding layer and a threshold current of only 18 mA. The laser had stable transverse-mode oscillation with a beam astigmatism less than 1 μm.

Notes: 1.5 μm GaInAs/AlGaInAs multiquantum-well (MQW) lasers with 1% compressively strained quantum wells were grown by molecular-beam epitaxy. The effective differential gain (g0) determined from the squared relaxation oscillation frequency versus output power relations is a high value of 9.3×10−16 cm2 in long-wavelength lasers. On the other hand, the effective transparent carrier density (n0) of strained-layer MQW lasers determined from the measurement of the spontaneous carrier lifetime was found to be very high, which is different from the theory of strain effects. However, by taking the carrier transport effect into account, it was shown that (1) for the strained MQW lasers the intrinsic transparent carrier density is lower than that of the lattice-matched MQW lasers, and (2) the intrinsic value of g0 is estimated to be 28–56×10−16 cm2, which is close to the theoretically predicted value. By improving the laser structure to have better carrier transport, much higher effective differential gain and lower effective transparent carrier density can be expected. © 1995 American Institute of Physics.

Notes: DNA damage generated by reactive oxygen species (ROS) has been implicated in ageing and in the pathogenesis of cardiovascular disease. Reactive oxygen species have also been demonstrated to play a crucial role in the pathophysiology of various renal diseases. They are extremely vulnerable to oxidative stress because mitochondria are the major intracellular source of ROS and have limited protection from oxidative stress. We have found increased accumulation of 8-hydroxy-2′-deoxyguanosine (8-OH-dG), which is a product and bio-marker of oxidative DNA damage, in the mitochondria of glomeruli and tubules in patients with IgA GN. The hOGG1 gene encodes a DNA glycosylase that excises 8-OH-dG from damaged DNA. Recently, genetic polymorphism of Ser(S)326Cys(C) has been reported. In addition, the enzymatic activity of hOGG1 in the repair of 8-OH-dG has been reported to be greater with S than with C.In this study, we investigated the correlation between hOGG1 polymorphism and the clinical phenotypes in Japanese patients with IgA GN. A total of 100 patients with IgAGN with a clinical course of over 7 years duration whose diagnosis was made by renal biopsy were divided into the ‘CRF group’ and the ‘fair group’. The CRF group consisted of 30 patients whose creatinine clearance (Ccr) had fallen to less than 50% of that during the initial period or they had developed end stage renal failure (ESRF). The fair group consisted of 62 patients whose Ccr had been kept at over 80% of that during the initial period, even 7 years after the diagnosis. The patients were genotyped and their clinical findings were compared. One hundred healthy Japanese subjects with normal urinalysis and renal function were analysed. The patients and controls were informed of the ethical approval of this study before entry into the study. The genotype of the hOGG1 gene was determined using the PCR-SSCP method followed by direct sequencing analysis. The details of PCR-SSCP methods have been previously described.1 Clinical and biochemical data were extracted from case records. Blood pressure was evaluated as the average during 1 week of the patient’s hospitalization for a first renal biopsy. Proteinuria was also evaluated as the average data obtained from 24 h collected urine samples for a week. Significant differences in allele frequency and genotype between groups were tested by χ2 test. Biochemical and clinical data were tested by ANOVA and the t-test.We found a high frequency of the C allele in the CRF group compared to the fair group and controls (P 〈 0.05, 〈link href="#t1"〉Table 1). The frequency of ESRF patients was significantly higher among the patients with the CC genotype than in those woth the CS and SS genotype (CC, CS, SS = 50%, 27%, 16%; CC vs CS, P 〈 0.05; CC vs SS, P 〈 0.01; 〈link href="#f1"〉Fig. 1).〈tabular xml:id="t1"〉1〈title type="main"〉 Genotype and allele frequencies in each group 〈mediaResource alt="image" href="urn:x-wiley:13205358:NEP7:NEP_7_t1"/〉〈figure xml:id="f1"〉1〈mediaResource alt="image" href="urn:x-wiley:13205358:NEP7:NEP_7_f1"/〉Frequency of ESRF patients in each group.The creatinine increase rate CC, CS, SS = 0.6090 ± 0.924, 0.1998 ± 0.561, 0.0766 ± 0.2558 mg/dL per year, P 〈 0.05, 〈link href="#t2"〉Table 2) and proteinuria (CC, CS, SS = 1.89 ± 2.24, 1.02 ± 1.07, 1.17 ± 1.57 (g/24 h), P 〈 0.05) were significantly higher in the patients with the C allele than in those with the S allele.〈tabular xml:id="t2"〉2〈title type="main"〉 Creatinine increase rate and proteinuria in each group 〈table frame="topbot"〉〈tgroup cols="5" align="left"〉〈colspec colnum="1" colname="col1" align="left"/〉〈colspec colnum="2" colname="col2" align="center"/〉〈colspec colnum="3" colname="col3" align="center"/〉〈colspec colnum="4" colname="col4" align="center"/〉〈colspec colnum="5" colname="col5" align="left"/〉〈thead valign="bottom"〉〈row rowsep="1"〉CCCSSS〈tbody valign="top"〉Crn increase rate0.6090 ± 0.9240.1998 ± 0.5610.0766 ± 0.2558(mg/dL per year)Proteinuria1.89 ± 2.241.02 ± 1.071.17 ± 1.57(g/24 h)〈note xml:id="t2_note4" numbered="no"〉 P 〈 0.05These findings indicate that the polymorphism of the hOGG1 gene is associated with progression of IgA GN. hOGG1 polymorphism correlates with the amount of proteinuria and a decreasing speed of renal function. In this study, the patients with the CC genotype tended to fall into ESRF. A previous study disclosed that the ability to excise 8-OH-dG is greater with the S allele than with the C allele.2 These facts suggest that accumulation of oxidative DNA damage might be an important factor in the progression of IgA GN. Excision oxidative DNA damage, which is genetically decided, may play an important role in IgA GN.