Electric-Field Induced Activation of Dark Excitonic States in Carbon Nanotubes.

Electrical activation of optical transitions to parity-forbidden dark excitonic states in individual carbon nanotubes is reported. We examine electric-field effects on various excitonic states by simultaneously measuring photocurrent and photoluminescence. As the applied field increases, we observe an emergence of new absorption peaks in the excitation spectra. From the diameter dependence of the energy separation between the new peaks and the ground state of E11 excitons, we attribute the peaks to the dark excited states which became optically active due to the applied field. Field-induced exciton dissociation can explain the photocurrent threshold field, and the edge of the E11 continuum states has been identified by extrapolating to zero threshold.

Variation of atmospheric tritium concentration in three chemical forms at Toki, Japan: 2004-12.

Atmospheric tritium concentrations of HTO, HT and CH3T have been measured at Toki, Japan, for the environmental impact assessment of tritium for a fusion test facility. According to the data from 2004 to 2012, the concentrations of HT and HTO in water vapour tend to increase in spring. The seasonal variation in HT concentration at Toki was compared with the H2 concentration between 1990 and 2005 at Tae-ahn Peninsula, Republic of Korea, which is at approximately the same latitude as Toki. The monthly average of HT-specific activity varied from 1.24 × 10(5) to 1.76 × 10(5) TU. The peak of the monthly average H2 concentration did not match that of HT. This indicates that the mechanism of the production or the source of HT might be different from the production mechanism of H2.

FWT and OBT concentrations in pine needle samples collected at Toki, Japan (1998-2012).

Free water tritium (FWT) and organically bound tritium (OBT) concentrations in pine needles have been investigated to understand the regional background tritium concentration in Toki City. Samples were regularly collected from pine trees on the National Institute for Fusion Science campus (1998-2012) and the nearby Shiomi Park (SP; 2002-12). FWT and OBT concentrations of the former samples ranged from 0.33 to 0.92 and 0.41 to 1.10 Bq l(-1), respectively, while those of the latter samples ranged from 0.32 to 0.86 and 0.33 to 0.79 Bq l(-1), respectively. Results of both sampling sites were almost the same, and they have been gradually decreased year by year. Concentration level of tritium for Toki City was close to the average background level in Japan. The OBT/FWT ratios were almost 1.0. The apparent half-life of FWT in this period was estimated as almost 10 y, and that of OBT was estimated as almost 12 y; these values were almost the same as the physical half-life.

Preparation of monoclonal antibodies against methamphetamine.

15 monoclonal antibodies against methamphetamine (MA) were obtained from hybridoma clones by the fusion of mouse 653 myeloma cells with the spleen cells of the immunized mice. The monoclonal antibodies exhibited different cross-reactivities against MA-related compounds and one antibody (MA-15 Ab) was highly specific against MA. A competitive inhibition enzyme-linked immunosorbent assay was established and the detection limit for MA was approximately 20 ng/ml.

Characterization of morphine-specific monoclonal antibodies showing minimal cross-reactivity with codeine.

Six murine monoclonal antibodies against morphine were produced using N-(4-aminobutyl)normorphine as a hapten. Most of the antibodies obtained distinguished the substituents at the 3 and 6 positions of morphine. This property of the antibodies led to a reduction in cross-reactivity with codeine, morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) to negligible levels. However, one of the antibodies distinguished the substituent only at the 3 position of morphine, which cross-reacted with M-6-G, naloxone and naltrexone. In the competitive inhibition enzyme-linked immunosorbent assay, morphine was detected at concentrations as low as circa 100 pg/ml.

Serum-manganese-superoxide dismutase: normal values and increased levels in patients with acute myocardial infarction and several malignant diseases determined by an enzyme-linked immunosorbent assay using a monoclonal antibody.

An enzyme-linked immunosorbent assay (ELISA) has been developed for human manganese-superoxide dismutase (Mn-SOD), using a specific monoclonal antibody raised against the purified enzyme. The Mn-SOD molecule comprises four identical sub-units and this permitted the development of a symmetrical assay, using the same monoclonal antibody as both capture and detector. The assay offers a specific, sensitive and convenient means of measuring immunoreactive Mn-SOD in human sera. Under optimum conditions, the sensitivity of the assay permits the detection of 2-200 ng of purified Mn-SOD from human liver. The mean serum Mn-SOD levels of normal healthy males and females were 99.8 +/- 24.8 (mean +/- SD) and 88.8 +/- 20.8 (mean +/- SD), respectively. A high level of the enzyme was found in the sera of patients with acute myocardial infarction as well as malignant diseases such as acute myeloid leukemia, primary hepatoma and gastric cancer. This is the first report of an ELISA using a monoclonal antibody specific for a distinct epitope of Mn-SOD.

Atomic and electronic origins of a type- C defect on Si(001)

We present an extensive set of ab initio calculations for a type- C defect on Si(001). Various models belonging to subsurface defects are studied. A substitutional B in the second surface layer is predicted as a possible atomic origin of this defect. However, H and O coupled with second-layer vacancies and a substitutional C are not responsible for a type- C defect. We also discuss how the electronic structure of a type- C defect contributes to its specific scanning tunneling microscopy images.

Species-specific epitopes exist on the cytoplasmic amino-terminal domain of erythrocyte band 3 protein.

Monoclonal antibodies (P3-9H, P3-1F, P3-2H, P3-4A, and P3-4C) to human erythrocyte band 3 were produced using human erythrocyte membranes as the immunogen. All epitopes defined by these antibodies were found on the amino-terminal cytoplasmic domain of erythrocyte band 3. The antibodies crossreacted variously with erythrocyte band 3 of primates (chimpanzee, orangutan, Rhesus monkey, Japanese monkey, spider monkey, and capuchin monkey) in enzyme-linked immunosorbent assay. P3-9H did not crossreact with erythrocyte band 3 of any primate examined; P3-1F crossreacted only with that of chimpanzee; P3-2H crossreacted with erythrocyte band 3 of chimpanzee, spider monkey, and capuchin monkey; and P3-4A and P3-4C crossreacted with erythrocyte band 3 of all primates examined. These results suggest that evolutional changes in primates are accumulated in the amino-terminal cytoplasmic domain of band 3 and that species-specific epitopes exist on this domain.

An approach for an immunoaffinity AIDS sensor using the conservative region of the HIV envelope protein (gp41) and its monoclonal antibody.

A monoclonal antibody for the conservative region of gp41, which is one of the HIV envelope proteins, was produced. The antigen determining site of gp41 was examined using the epitope mapping technique, followed by an enzyme linked immunosorbent assay. Some peptides had comparable affinities for the monoclonal antibody, but the peptide EGIEE, having a slightly weaker immunoaffinity than gp41, was the most preferable for the construction of an immunoaffinity AIDS sensor. For the detection of gp41, EGIEE was labelled with catalase and used as a mimic antigen; it was bound to the antibody present on an immuno-membrane and, due to the replacement reaction of the mimic antigen by gp41, indirect quantitative measurement of gp41 was possible using an oxygen electrode. Anti-gp41 antibody was also detected using a mimic antibody, which was chemically modified with polyethylene glycol. An immunoaffinity AIDS sensor was constructed using the mimic molecules which were tailored to have a suitable immunoaffinity for HIV antigen and/or antibody.

Zinc hydroxide induced respiratory burst in rat neutrophils.

The effects of zinc hydroxide on the respiratory burst and phagocytosis by rat neutrophils were examined. Zinc hydroxide induced an increase in oxygen consumption and O2- production. Electronmicroscopy showed that neutrophils engulfed zinc hydroxide particles by phagocytosis. Pertussis toxin (0.25, 0.5, 1.0 micrograms/ml) and EGTA (1, 2, 5 mM) inhibited zinc hydroxide-induced O2- production in a dose-dependent manner. The inhibitors of protein kinase C, 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine and N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide inhibited zinc hydroxide-induced O2- production with IC50 values ranging between 10 microM and 25 microM. The inhibitory study using an inhibitor of myosin light chain kinase, 1-(5-iodo-naphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine, showed IC50 values ranging from 5 microM to 10 microM. These findings indicate that zinc hydroxide induces respiratory burst and phagocytosis by rat neutrophils.

Superoxide dismutase in normal cycling human ovaries: immunohistochemical localization and characterization.

OBJECTIVE: To investigate the expression of manganese (Mn) and copper-zinc (Cu,Zn) superoxide dismutase (SOD) in normal cycling human ovaries throughout the menstrual cycle. DESIGN: Descriptive, controlled study. SETTING: Tohoku University School of Medicine. PATIENT(S): Twenty-four normal cycling human ovaries were obtained from patients who underwent oophorectomy and hysterectomy for squamous cell carcinoma of the uterine cervix. INTERVENTION(S): Immunohistochemistry for Mn-SOD and Cu,Zn-SOD. MAIN OUTCOME MEASURE(S): Immunostaining. RESULT(S): In the follicular stage, Mn-SOD immunoreactivity was detected in granulosa and theca interna cells of steroid-producing follicles, that is, preantral, nondominant, dominant, and atretic follicles, whereas Cu,Zn-SOD was detected in theca interna cells of these follicles and in granulosa cells of dominant follicles. In the luteal stage, immunoreactivity for Mn-SOD and Cu,Zn-SOD was observed in both luteinized granulosa and theca cells of the functioning corpus luteum. In the early degenerating corpus luteum, both Mn-SOD and Cu,Zn-SOD were positive in steroid-producing luteinized theca cells. Mn-SOD immunoreactivity was also detected in nonsteroid-producing luteinized granulosa cells and macrophages. CONCLUSION(S): Our results suggest that the expression of Mn-SOD and Cu,Zn-SOD closely correlates with steroidogenesis in the human ovary. In addition, Mn-SOD may play an important role in the process of luteal regression.

Human serum immuno-reactive copper, zinc-superoxide dismutase assayed with an enzyme monoclonal immunosorbent in patients with digestive cancer.

Two types of monoclonal antibodies, N4 and N6, were raised against human copper, zinc-superoxide dismutase (Cu,Zn-SOD). An enzyme-linked immunosorbent assay for Cu,Zn-SOD was developed in sandwich method using these monoclonal antibodies. The measurable assay range was 1.0-100 micrograms/l and the coefficient of variation within and between series were 7.5% and 8.1%. Sera of 154 healthy control subjects displayed a low level (14 micrograms/l) of immunoreactive Cu,Zn-SOD with a logarithmic normal distribution. On the other hand, serum Cu,Zn-SOD levels were significantly elevated in patients with various digestive cancers.

Preparation of monoclonal antibodies against okadaic acid prepared from the sponge Halichondria okadai.

Three murine monoclonal antibodies, OA-1, OA-2 and OA-3, against okadaic acid were prepared from hybridoma clones obtained by fusion of mouse 653 myeloma cells with mouse immune spleen cells sensitized to okadaic acid-ovalbumin conjugate. Each antibody reacted with dinophysistoxin-1 ( = 35-methylokadaic acid) as well as okadaic acid, but did not react with the other diarrhetic shellfish poisons or related compounds, such as 7-O-palmitoyl-okadaic acid (analogue of dinophysistoxin-3), pectenotoxin-1 and yessotoxin. A competitive inhibition enzymelinked immunosorbent assay which employed OA-3 antibody was performed and showed a sensitivity of about 10 ppb (10 ng/ml) for okadaic acid. This simple and time-saving ELISA assay system may be useful for the specific detection of diarrhetic shellfish poisons.

Super catalytic antibody [I]: decomposition of targeted protein by its antibody light chain.

Obtaining an antibody capable of destroying a targeted protein is the eventual goal in developing superior catalytic antibody. We established a monoclonal antibody recognizing a highly conserved sequence, RGPDRPEGIEEEGGERDRD, of gp41 of the HIV-1 envelope. The obtained antibody reacted with gp41 and gp160 of HIV-1. The isolated and purified light chain not only decomposed the above antigenic peptide but also destroyed the gp41 molecule, indicating a novel ability. The decomposition of the antigen is presumably started by scission of the peptide bond between Arg-Gly in the above sequence. The light chain did not decompose BSA and HSA at all, showing the high specificity to antigens. The antibody light chain is referred to as a super catalytic antibody.

Analysis of the antigen recognition sites of anti-methamphetamine monoclonal antibodies (II): unique feature of MA-3 antibody.

A monoclonal antibody against methamphetamine (MA-3 mAb) was found to be strongly bound to ephedrine. This feature was quite different from that of other fourteen mAbs against MA. Analyses of cDNA sequence and steric conformation by molecular modeling revealed that one hydrophilic pocket was generated in the heavy chain of MA-3 mAb involving CDRH-1 and CDRH-2. Asn33, Asn35, Asn50 and Asp52 were the main components of the unique pocket capable of binding to the hydroxyl group of ephedrine.

Coronary artery calcification detected by CT: clinical significance and angiographic correlates.

Cardiac computed tomography (CT) to detect coronary calcification was performed on 161 patients undergoing coronary angiography for proven or suspected coronary artery disease. Among 108 patients in whom coronary calcifications was identified, 90% had significant coronary stenosis angiographically (greater than 75% stenosis), and 80% of 121 patients with significant coronary stenosis showed calcification by CT. The relationship between the calcification site and the significance in stenosis of each vessel was determined. Calcification was present in 133 arteries among 205 stenotic coronary arteries (sensitivity = 65%) as compared with 59 of 439 entire arteries with normal coronary angiograms (specificity = 87%). In the younger age group the sensitivity of calcification for stenosis of each coronary artery was lower and the specificity and predictive value were generally higher than those in the elderly group. These results demonstrate that CT is a valuable procedure for detecting coronary arterial disease, since this examination is easy to conduct, noninvasive, and widely applicable for screening a large population.

Clinical importance of coronary calcification detected by CT.

Coronary calcifications appear in advanced atheromatous lesions therefore fluoroscopy is useful for the detection of the atherosclerotic coronary artery disease (Aldrich et al., 1979). However, the detection of coronary calcification by fluoroscopy is difficult in the case of obesity or thick chest wall and also impaired by the background structures including bone and other intrathoracic calcifications. X-ray CT is more advantageous than fluoroscopy in the detection of coronary calcification. It can eliminate the interference from background structures and clearly demonstrates calcified sites of the coronary artery. Therefore, we investigated the clinical usefulness in the detection of coronary calcification with X-ray CT.

How and why 41S-2 antibody subunits acquire the ability to catalyze decomposition of the conserved sequence of gp41 of HIV-1.

It has become well known that antibodies obtained by immunization with the ground state of peptides can display proteolytic activity. Our antibody light chain produced by immunization with the peptide RGPDRPEGIEEEGGERDRD, a highly conserved sequence in envelope gp41 of HIV-1 showed the ability to cleave this peptide. Moreover, its heavy chain also decomposed the peptide, although this occurred at lower activity levels compared with the light chain, while the whole antibody did not show any catalytic activity. From molecular modeling, the light and heavy chains of the antibody were deduced to possess catalytic triads (Asp, His, and Ser) in their steric conformations, which may be responsible for the observed proteolytic activity.

Efficiency estimation for detecting U alpha particles in solid-state nuclear track detectors.

The detection efficiencies of solid-state nuclear track detectors, made with cellulose nitrate materials (LR-115 II) or allyl diglycol carbonate (CR-39) were investigated. Detection efficiency for a surface alpha source was experimentally obtained by changing the dimensions between the detector and the source, while alpha-particle incident efficiency was calculated. The ratio of the detection efficiency to the incident efficiency was then determined. It was confirmed that the ratio for LR-115 II was dependent on energy, but for CR-39 the ratio showed almost no dependency. Considering the relationship between solid absorber thickness and detection efficiency of the surface alpha source, detection efficiencies of U in various metals were estimated. The efficiency for U contained in Al and Fe was proposed as 16% for LR-115 II and 22% for CR-39. Using these efficiencies, amounts of U in some Al and Fe ingots were determined. These agreed with concentrations obtained by neutron-activation analysis with deviations of less than 15%.

sLORETA-qm for interictal MEG epileptic spike analysis: comparison of location and quantity with equivalent dipole estimation.

OBJECTIVE: To determine whether quantitative modification of a standardised low-resolution brain electromagnetic tomography (sLORETA-qm) could be used as a reliable tool for quantitative analysis of magnetoencephalography (MEG) for analysis of the interictal epileptic spike. To verify the performance of sLORETA-qm, magnetic source location and quantity were compared with the equivalent current dipole (ECD) method. METHODS: A total of 50 sources from 10 patients with epilepsy were obtained. Analyses were performed after the MEG data were 3-70 Hz band-pass filtered. Time points for analysis were selected referring to waveform patterns and the isofield contour map. With the same spherical model, source estimation was conducted with two methods of analysis: ECD and sLORETA-qm. Distance from the centre of the spherical model and intensities were compared between the methods. RESULTS: There were no significant differences between the methods in the distance from the spherical model (paired t-test, p=0.8761). Source intensities between the methods were strongly correlated (Spearman's Rho=0.9803, p<0.001). CONCLUSIONS: sLORETA-qm was closely correlated with ECD concerning point source location and quantity in analysis of the interictal epileptic spike. SIGNIFICANCE: sLORETA-qm is a reliable quantifiable method without arbitrariness for analysis of the interictal epileptic spike.