Metal-insulator transition in the quasi-one-dimensional transport of fractional quantum Hall states.

We investigate edge state transmission in quantum point contacts (QPCs) in the fractional quantum-Hall regime, finding behavior reminiscent of a metal-insulator transition. The transition is suggested by an unusual behavior of the differential conductance in the fractional-quantum-Hall regime, and by the presence of a fixed point and universal scaling in the temperature dependence of the linear conductance. Noting that the 0.7 feature evolves continuously into a last fractional plateau at high magnetic fields, we suggest that this still unresolved feature may itself be viewed as a manifestation of a local, microscopic, metal-insulator transition.

On the zero-bias anomaly and Kondo physics in quantum point contacts near pinch-off.

We investigate the linear and non-linear conductance of quantum point contacts (QPCs), in the region near pinch-off where Kondo physics has previously been connected to the appearance of the 0.7 feature. In studies of seven different QPCs, fabricated in the same high-mobility GaAs/AlGaAs heterojunction, the linear conductance is widely found to show the presence of the 0.7 feature. The differential conductance, on the other hand, does not generally exhibit the zero-bias anomaly (ZBA) that has been proposed to indicate the Kondo effect. Indeed, even in the small subset of QPCs found to exhibit such an anomaly, the linear conductance does not always follow the universal temperature-dependent scaling behavior expected for the Kondo effect. Taken collectively, our observations demonstrate that, unlike the 0.7 feature, the ZBA is not a generic feature of low-temperature QPC conduction. We furthermore conclude that the mere observation of the ZBA alone is insufficient evidence for concluding that Kondo physics is active. While we do not rule out the possibility that the Kondo effect may occur in QPCs, our results appear to indicate that its observation requires a very strict set of conditions to be satisfied. This should be contrasted with the case of the 0.7 feature, which has been apparent since the earliest experimental investigations of QPC transport.

Studies of soft X-ray-induced Auger effect on the induction of DNA damage.

PURPOSE: To understand the characteristics of DNA damage induced by Auger effect in DNA by ultrasoft X-irradiation. In situ electron paramagnetic resonance (EPR) spectroscopy as well as biochemical analysis has been applied to examine the DNA damage induction in both viewpoints of intermediate species and final products. MATERIALS AND METHODS: Unpaired electron species induced in a calf thymus DNA film irradiated with monochromatic ultrasoft X-rays (270-580 eV) was observed using an X-band EPR spectrometer installed in a synchrotron beamline. To determine the yield of single strand break (SSB), pUC18 plasmid DNA was irradiated and then analyzed by agarose gel electrophoresis. To analyze molecular change in a single strand DNA, a new technique using DNA-denaturation-treatment has been applied to quantify multiple SSB arising in both DNA strands. RESULTS: Short-lived EPR spectra were observed during irradiation. The intensity of transient EPR spectrum shows the similar energy dependence with that of the SSB yield around oxygen K-edge in particular. The fraction of the single-strand plasmid DNA (SS-DNA) after irradiation could be determined using a low-temperature-denaturation condition. The obtained slope of the dose-response for SS-DNA shows half of that of closed circular DNA as expected under the diluted solution condition. CONCLUSION: The availability of an EPR apparatus installed in a synchrotron beamline is demonstrated by detecting very short-lived unpaired electron species. Transient EPR spectra of DNA show the similar energy dependence to that of the SSB yield. The proposed DNA-denaturation assay works as expected using the low-temperature-denaturation condition.

A set of polymorphic trinucleotide and tetranucleotide microsatellite markers for the Japanese flounder (Paralichthys olivaceus).

We have developed the first set of trinucleotide and tetranucleotide markers for the Japanese flounder, Paralichthys olivaceus. One hundred and sixty-seven polymorphic trinucleotide and tetranucleotide microsatellites were isolated using clones derived from two libraries. Of almost 200,000 clones analysed, 0.5% presented trinucleotide or tetranucleotide repeat regions. Among the trinucleotide repeats analysed in this study, the most frequent one was (CAG)(n) and the most common tetranucleotide repeat was (GATA)(n). The position of the new markers in the genetic linkage map was determined. Markers were evenly distributed along the P. olivaceus linkage groups, without distinction between the kinds of repeats and library of origin. The markers isolated in this study contribute significantly to the genetic linkage map of the Japanese flounder.

Pilot evaluation of selective serotonin reuptake inhibitor antidepressants in hot flash patients under androgen-deprivation therapy for prostate cancer.

PURPOSE: Hot flash (HF) is a common side effect in prostate cancer patient undergoing androgen-deprivation therapy (ADT). In this study, we evaluated the efficacy of paroxetine (selective serotonin reuptake inhibitors (SSRIs)) for HF. PATIENTS AND METHODS: In total, 10 men with prostate cancer under ADH who were suffering with HF entered this study. Self-report questionnaire was used for the evaluation. RESULTS: The average rating for HF frequency decreased (P=0.009) and HF severity decreased (P=0.0332) also, reported QOL score increased (P=0.0218). CONCLUSION: These preliminary data suggest that low dose (10 mg/day) of antidepressant paroxetine can be helpful in the treatment of HFs in patients under ADT for prostate cancer. Further controlled studies are needed to more fully evaluate the efficacy of the SSRIs.

Visual recognition of triamines by phenolphthalein derivatives: consideration of the structure of the colored complex.

[structure: see text] A hybrid molecule 1 consisting of phenolphthalein and two crown ether moieties can be used to discriminate the length of linear triamines strictly by color development. The purple color is developed most deeply at -10 degrees C and fades with either an increase or decrease in temperature.

Visual enantiomeric recognition using chiral phenolphthalein derivatives.

[structure: see text] Optically active artificial host molecules 2-5 based on a phenolphthalein skeleton have been prepared for visual enantiomeric recognition of alanine derivatives 8 and 9. The receptor 3 discriminates (R)-8 and (R)-9 from (S)-8 and (S)-9, respectively, to develop a purple color.

A case of renal ptosis treated with hochu-ekki-to with improvement confirmed by excretory urography.

A 59-year-old woman visited our clinic with complaints of right back dull pain. Excretory urography showed bilateral renal ptosis (a 6 cm decrease in position of the right kidney and a 5 cm decrease of the left kidney). She was treated with 7.5 g/day of Hochu-ekki-to. After 6 months, her symptoms improved and after 8 months excretory urography showed a 3 cm decrease in the position of both kidneys. Hochu-ekki-to might be useful for the conservative therapy of renal ptosis.

Synthesis of configurationally defined sexi- and octinaphthalene derivatives.

[figure: see text] Configurationally defined optically active octinaphthalenes were synthesized using the oxidative coupling of optically active quaternaphthalenes with a 2-hydroxynaphthol moiety as a key reaction. The absolute configuration was determined by comparison with products of [6 + 2] coupling.

Conformation of 1,4-dineopentyl-2,5-cis-diphenylpiperazine and its diammonium salts: remarkable change in conformation depending upon the counter anion.

The free base of 1,4-dineopentyl-2,5-diphenylpiperazine takes a chair conformation in CDCl3, while the conformation of its diammonium salts changes depending upon the counter anion.

The first example for cycloenantiomeric hexahomooxacali.

Cycloenantiomeric hexahomooxacalix[3]arenes with different substituents on the three upper rims were synthesized for the first time by fixing their conformation into a cone. A cycloenantiomeric hexahomooxacalix[3]arene 6 was resolved into both enantiomeric forms and chiroptically characterized. Preliminary 1H-NMR studies indicated that the optically resolved cycloenantiomer 6 could discriminate the enantiomers of hydrochloride of phenylalanine ethyl ester.

Memory of chirality in diastereoselective alpha-alkylation of isoleucine and allo-isoleucine derivatives.

[reaction: see text] alpha-Methylation of 3 gave 5 as a major product whereas 4 gave 6 predominantly, although both 3 and 4 have an (S)-chiral center at C(3). This indicates that chirality at C(2) in 3 and 4 was memorized in the corresponding intermediate enolates and the induced chirality made a major contribution in the stereochemical course of the reaction, while chirality at the adjacent chiral center C(3) had little effect.

Nonphotic entrainment by 5-HT1A/7 receptor agonists accompanied by reduced Per1 and Per2 mRNA levels in the suprachiasmatic nuclei.

In mammals, the environmental light/dark cycle strongly synchronizes the circadian clock within the suprachiasmatic nuclei (SCN) to 24 hr. It is well known that not only photic but also nonphotic stimuli can entrain the SCN clock. Actually, many studies have shown that a daytime injection of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH DPAT), a serotonin 1A/7 receptor agonist, as a nonphotic stimulus induces phase advances in hamster behavioral circadian rhythms in vivo, as well as the neuron activity rhythm of the SCN in vitro. Recent reports suggest that mammalian homologs of the Drosophila clock gene, Period (Per), are involved in photic entrainment. Therefore, we examined whether phase advances elicited by 8-OH DPAT were associated with a change of Period mRNA levels in the SCN. In this experiment, we cloned partial cDNAs encoding hamster Per1, Per2, and Per3 and observed both circadian oscillation and the light responsiveness of Period. Furthermore, we found that the inhibitory effect of 8-OH DPAT on hamster Per1 and Per2 mRNA levels in the SCN occurred only during the hamster's mid-subjective day, but not during the early subjective day or subjective night. The present findings demonstrate that the acute and circadian time-dependent reduction of Per1 and/or Per2 mRNA in the hamster SCN by 8-OH DPAT is strongly correlated with the phase resetting in response to 8-OH DPAT.

The '2+1' construction of homooxacalix[3]arenes possessing different substituents on their upper rims.

Several homooxacalix[3]arenes possessing different substituents on their upper rims were synthesized in yields of 7-20% by a condensation reaction between the p-substituted-phenol dimer and monomer under acidic high-dilution conditions.

Conformational difference between mono- and diprotonated cis-2,5-diphenylpiperazinium salts in the solid state.

Monohydrochlorides of cis-2,5-diphenylpiperazine assume a chair conformation, while the corresponding dihydrochlorides assume a boat form regardless of the substituent(s) at the nitrogen atom.

Long-term results of lipiodol-transcatheter arterial embolization with cisplatin or doxorubicin for unresectable hepatocellular carcinoma.

The long-term effects of Lipiodol-transcatheter arterial embolization (Lp-TAE) combined with cisplatin (CDDP) or doxorubicin (ADM) on unresectable hepatocellular carcinoma (HCC) were analyzed. Eighty-four consecutive patients with unresectable HCC were treated with TAE. Of the 84, 38 patients were treated with CDDP-Lp-TAE (CDDP group), whereas the remaining 46 patients were treated with ADM-Lp-TAE (ADM group). No significant difference in characteristics of patients and tumors was noted between the groups. CDDP (50 mg) or ADM (20-50 mg) was administered with Lp followed by embolization of the feeding arteries using gelatin sponge particles. The mean number of TAE treatments was 3.3 in the CDDP group and 1.9 in the ADM group (p < 0.01). The 5-year overall survival rates of the CDDP group and the ADM group were 19% and 6%, respectively. The overall survival rate of the CDDP group was significantly higher than that of the ADM group (p < 0.05). No serious side effects were observed in either group. CDDP-Lp-TAE improved the prognosis of unresectable HCC compared with ADM-Lp-TAE, which may be attributable to the fact that CDDP-Lp-TAE treatment could be repeated more times than ADM-Lp-TAE.

DNA oligomers having a diazapyrenium dication (DAP2+); synthesis and DNA cleavage activities.

Aiming at the creation of functionalized antisense DNA oligomers possessing site-selective DNA cleaving activity, viologen and a related compound, diazapyrenium dication (DAP2+), were selected and introduced into oligodeoxyribonucleotides as a functionalized molecule. The conjugation of these functionalized molecules with DNA proceeded smoothly by using standard H-phosphonate chemistry. A part of the DAP(2+)-tethered DNA oligomers was synthesized by a combination of solid support method and liquid phase technique. Viologen-tethered DNA oligomers showed no significant activity toward DNA cleavage in spite of their characteristic ESR spectra. On the other hand, it was observed that the DAP(2+)-tethered DNA oligomers formed more stable duplexes with their complementary strands than the corresponding wild type, and these molecules effectively cleaved the complementary strands at the specific site of 2-3 bases away from the modified phosphoramidate linkage. The effect of position and length of the linker arm on the selectivity in the cleavage reaction was also investigated, and it was found that introduction at the 3'- or 5'-end phosphate site is more favorable, probably due to duplex stabilization.