Search

CANDLES studies the double beta decay of 48Ca through CaF2scintillation crystals. The CANDLES III detector, located in Kamioka underground laboratory, is currently running. Here we describe recent status of data analysis which includes detector performance, detector stability, and background estimation. Current sensitivity for 0νββhalf-life is also discussed in this paper.

We have experimentally evaluated the background noise in a Cauchois-type high-resolution Compton scattering spectrometer at SPring-8. The signal-to-noise ratio (S/N) in the energy profile of Compton scattered X-rays from 3 mm thick Cu was found to be 78 at the Compton peak for the incident X-ray energy of 115 keV. The experimental S/N is in good agreement with the value of 80 estimated from simple considerations. The achieved S/N in the spectrometer is high enough for most Compton scattering experiments.

An X‐ray spectrometer for high‐resolution Compton profile measurements using 90–120 keV X‐rays has been designed and constructed at SPring‐8. A Cauchois‐type triply layered bent‐crystal analyzer was employed for the energy analysis. A novel use of a solid‐state detector with a large active area was devised as a position‐sensitive detector. A resolution of 0.10 atomic units in electron momentum has been achieved at an incident X‐ray energy of 115 keV. A Compton profile of a single crystal of Nb was measured with a counting rate of 30 counts s−1at the Compton peak, which demonstrates that the spectrometer is capable of measuring Compton profiles of heavy‐element materials.

Nitric oxide is the most potent vasodilator among inflammation-mediated vasoactive substances. Tepid cardiopulmonary bypass has been known to maintain low vascular resistance and nitric oxide may also be involved. There has been no previous clinical study elucidating a role of nitric oxide in a temperature dependent regulation of systemic vascular resistance in cardiopulmonary bypass.

A photon beam‐position monitor using a diamond foil as a position‐sensitive device has been developed for use on insertion‐device beamlines of third‐generation synchrotron radiation facilities such as SPring‐8, and was tested on the undulator beamline of the Tristan Super Light Facility at KEK. The beam test results show that the diamond monitor can be operated in a photoconductive mode like a semiconductor detector. It has a linear working range of about ±1 mm and a position sensitivity of less than 3 μm. The stability of the monitor was confirmed by continuous operation under low photon beam intensity conditions.

In cardiac operations endopeptidase (protease) inhibitor may be beneficial in reducing myocardial injury when administered in the cardiopulmonary bypass prime. Nafamostat mesilate was evaluated in 20 patients who underwent coronary artery bypass grafting. The patients were divided into a control group ( n = 10) and a nafamostat group ( n = 10). Nafamostat (2 mg/kg per hour) was continuously given during cardiopulmonary bypass in the nafamostat group. The age, number of grafts, cardiopulmonary bypass time, and aortic crossclamp time were similar between groups. In the control group, neither tumor necrosis factor-@a nor interleukin-1 levels showed any significant change during cardiopulmonary bypass, whereas interleukin-6 and interleukin-8 levels, percent expression of adhesion molecule (CD18) on neutrophils, and CH"5"0assay results increased significantly during cardiopulmonary bypass. As compared with the control group, the nafamostat group showed significantly lower levels of interleukin-6 (123 +/- 57 versus 40 +/- 22 pg/ml, respectively) and interleukin-8 (96 +/- 13 versus 66 +/- 14 pg/ml, respectively). The nafamostat group showed a significantly lower difference of CH"5"0assay results and malondialdehyde levels between coronary sinus blood and arterial blood and peak values of creatine kinase MB (43 +/- 12 IU/L versus 19 +/- 6 IU/L) during the postoperative course compared with findings in the control group. These results demonstrated that inflammatory reactions induced by cardiopulmonary bypass had adverse effects on myocardial recovery after aortic crossclamping and that nafamostat mesilate given during cardiopulmonary bypass appeared to reduce myocardial reperfusion injury by attenuating such inflammatory reactions. Attenuation of inflammatory reactions of cardiopulmonary bypass should be considered in the strategy of myocardial protection. (J T horac C ardiovasc S urg 1996;111:29-35)

Although nitric oxide (NO) is an important biological mediator, excessive production in inflammation is thought to be a causative factor of cellular injury and cancer in the long term. In the present study the effects of 1'-acetoxychavicol acetate (ACA), which has anticarcinogenic properties, on NO production in murine macrophage cell line RAW264 cells stimulated with lipopolysaccharide or interferon-γ were examined. ACA suppressed NO production dose dependently with an IC₅₀ of 160 ng/ml (680 nM). The decrease in NO production was shown to parallel reduced expression of iNOS mRNA and protein. The influence of ACA on transcription factors, such as NF-κB, AP-1 and Stat1, which are involved in expression of the iNOS gene was assessed. ACA was found to suppress degradation of IκB, and NF-κB inhibitor factor, and consequently inhibit NF-κB activation. Activation of AP-1 and Stat1 was also blocked by ACA treatment. Thus we demonstrate that ACA exerts potent inhibitory effects on NO production, apparently mediated by modulation of activation of several transcription factors. This could contribute to the anticarcinogenic properties of ACA.

Not Available

Background: Reperfusion injury in the myocardium has recently been considered to be a type of inflammation, and close attention has been paid to the possible involvement of neutrophils, complement, and cytokines in the onset of this injury. Recently, it has been reported that serum levels of interleukin-6 are elevated significantly after myocardial infarction. The major site of interleukin-6 production and its exact roles are still unknown. In this study, we hypothesized that myocytes may produce interleukin-6 during hypoxia and this may play a role in neutrophil-mediated reperfusion injury. Methods and results: In the clinical study, 20 patients who underwent coronary artery bypass grafting were divided into 2 groups: group F, in which patients were treated with a serine protease inhibitor (FUT-175, 2 mg/kg per hour) during cardiopulmonary bypass, and group C (untreated patients). In group C, myocardial interleukin-6 production, as determined by the difference between the interleukin-6 level in the cardiopulmonary bypass circuit and its level in coronary venous blood, increased significantly after reperfusion (12 +/- 4 pg/mL) as compared with that before aortic crossclamping (2 +/- 2 pg/mL). In group F, the increase in the interleukin-6 level was suppressed significantly (before aortic crossclamping, 3 +/- 2 pg/mL; after reperfusion, 4 +/- 3 pg/mL). The interleukin-6 production differed significantly between group C and group F. In the in vitro experimental study, the supernatant from myocytes exposed to 2 hours of hypoxia (group 2H) showed significantly higher levels of interleukin-6 (455 +/- 260 pg/mL) than that from normoxic myocytes (group N) (47 +/- 15 pg/mL). This interleukin-6 production was suppressed by the addition of FUT-175 (123 +/- 24 pg/mL). The interleukin-6 production by endothelial cells of coronary vessels did not differ between group 2H (283 +/- 151 pg/mL) and group N (151 +/- 86 pg/mL). In a coincubation system with a monolayer of endothelial cells on collagen membrane and myocytes under collagen membrane in a modified Boyden chamber, 2 hours of coincubation showed a significantly higher percent of neutrophil transendothelial migration (group 2H vs N, 78% +/- 13% vs 26% +/- 11%), value of chemiluminescence (22 +/- 8 vs 5 +/- 2 x 10^3 counts/3 minutes), and percent of irreversibly damaged myocytes (48% +/- 17% vs 12% +/- 8%) than normoxic coincubation. In contrast, anti-interleukin-6 monoclonal antibody significantly attenuated neutrophil transendothelial migration (42% +/- 19%) and irreversible damage of myocytes (26% +/- 15%) in 2 hours of coincubation. Conclusions: Interleukin-6 is produced from myocardium during ischemia and reperfusion in patients undergoing coronary bypass grafting. This interleukin-6 may be derived from hypoxic myocytes and play a role in neutrophil-mediated reperfusion injury in myocardium. (J Thorac Cardiovasc Surg 1998;116:511-7)

Vertebrate limb formation has been known to be initiated by a factor(s) secreted from the lateral plate mesoderm. In this report, we provide evidence that a member of the fibroblast growth factor (FGF) family, FGF10, emanates from the prospective limb mesoderm to serve as an endogenous initiator for limb bud formation. Fgf10 expression in the prospective limb mesenchyme precedes Fgf8 expression in the nascent apical ectoderm. Ectopic application of FGF10 to the chick embryonic flank can induce Fgf8 expression in the adjacent ectoderm, resulting in the formation of an additional complete limb. Expression of Fgf10 persists in the mesenchyme of the established limb bud and appears to interact with Fgf8 in the apical ectoderm and Sonic hedgehog in the zone of polarizing activity. These results suggest that FGF10 is a key mesenchymal factor involved in the initial budding as well as the continuous outgrowth of vertebrate limbs.

Not Available

To elucidate what initiates formation of the limb, we have attempted to induce an additional limb from the flank of the chick embryo by infecting retrovirus or implanting cells. We report here that an additional limb can be formed from the flank when we implant fibroblast growth factor 4 (Fgf4)-expressing cells into the lateral plate mesoderm at the pre-limb bud stage. In a newly formed limb bud, expressions of both Sonic hedgehogand chick Fgf4, which are authentic morphogenetic signals from the zone of polarizing activity and the apical ectodermal ridge, respectively, are induced by the implanted cells. Thus, it is concluded that the competence for limb development is present along the flank of the chick embryo and that FGF4 applied ectopically at the pre-limb bud stage can alter the developmental fate of flank cells to become limb cells. The present experimental system will contribute to a further elucidation on how the limb is formed.

Although nitric oxide (NO) is an important biological mediator, excessive production in inflammation is thought to be a causative factor of cellular injury and cancer in the long term. In the present study the effects of 1'-acetoxychavicol acetate (ACA), which has anticarcinogenic properties, on NO production in murine macrophage cell line RAW264 cells stimulated with lipopolysaccharide or interferon-gamma were examined. ACA suppressed NO production dose dependently with an IC50 of 160 ng/ml (680 nM). The decrease in NO production was shown to parallel reduced expression of iNOS mRNA and protein. The influence of ACA on transcription factors, such as NF-kappaB, AP-1 and Stat1, which are involved in expression of the iNOS gene was assessed. ACA was found to suppress degradation of IkappaB, an NF-kappaB inhibitory factor, and consequently inhibit NF-kappaB activation. Activation of AP-1 and Stat1 was also blocked by ACA treatment. Thus we demonstrate that ACA exerts potent inhibitory effects on NO production, apparently mediated by modulation of activation of several transcription factors. This could contribute to the anticarcinogenic properties of ACA.

Continuous-wave (CW) operation up to 323K at 1 mW and up to 30 mW at room temperature has been demonstrated for 507nm ZnCdSe/ZnSSe/ZnMgSSe separate-confinement heterostructure (SCH) gain-guided laser diodes. The room temperature CW threshold current and voltage were 27 mA (Jth = 460 A/cm2) and 7.9 V, respectively, with 10 µm-wide stripe and 70/95% reflectivity facet.

Room temperature pulsed operation of ZnCdSe/ZnSe/ZnMgSSe SCH lasers has been achieved. Blue-green stimulated emission is observed at a wavelength of 498.5 nm. The threshold current density is 2.8 kA/cm2 for the diode made by molecular beam epitaxy.

Buried-heterojunction (BH) AlGaAs lasers were fabricated by one-step MOCVD epitaxial growth on an inverse mesa etched GaAs substrate. A low threshold current of 6 mA was obtained and the lasing wavelength was approximately 780 nm. The laser beam shape was nearly circular with an aspect ratio less than 1.3.

AlGaAs/GaAs distributed feedback (DFB) lasers with a ridge waveguide structure emitting at 0.88 μm were fabricated by normal-pressure metalorganic chemical vapour deposition (MOCVD). The DFB lasers have a low threshold current around 55 mA at room temperature and can be operated stably in a single longitudinal mode up to 40°C.

Continuous-wave operation in wide-gap II-VI semiconductor current injection laser diodes at room temperature has been demonstrated for the first time. Stimulated emission was observed at a wavelength of 523.5 nm with a threshold current of 45 mA (1.4 kA/cm2) from ZnCdSe/ZnSe/ZnMgSSe single-quantum-well (SQW) separate-confinement heterostructure (SCH) laser diodes.

At room temperature (296 K), continuous-wave (CW) operation of a blue laser diode has been achieved. The emission wavelength is 489.9 nm, and the threshold current and voltage is 93 mA (1.5 kA/cm2) and 6.3 V, respectively. The laser consists of a ZnCdSe/ZnSSe/ZnMgSSe single-quantum-well (SQW) separate-confinement heterostructure (SCH).

J Thorac Cardiovasc Surg 1998;116:876-7