An Ambipolar Superconducting Field-Effect Transistor Operating above Liquid Helium Temperature.

Superconducting (SC) devices are attracting renewed attention as the demands for quantum-information processing, meteorology, and sensing become advanced. The SC field-effect transistor (FET) is one of the elements that can control the SC state, but its variety is still limited. Superconductors at the strong-coupling limit tend to require a higher carrier density when the critical temperature (TC ) becomes higher. Therefore, field-effect control of superconductivity by a solid gate dielectric has been limited only to low temperatures. However, recent efforts have resulted in achieving n-type and p-type SC FETs based on organic superconductors whose TC exceed liquid He temperature (4.2 K). Here, a novel "ambipolar" SC FET operating at normally OFF mode with TC of around 6 K is reported. Although this is the second example of an SC FET with such an operation mode, the operation temperature exceeds that of the first example, or magic-angle twisted-bilayer graphene that operates at around 1 K. Because the superconductivity in this SC FET is of unconventional type, the performance of the present device will contribute not only to fabricating SC circuits, but also to elucidating phase transitions of strongly correlated electron systems.

Unconventional Magnetic and Resistive Hysteresis in an Iodine-Bonded Molecular Conductor.

Simultaneous manipulation of both spin and charge is a crucial issue in magnetic conductors. We report on a strong correlation between magnetism and conductivity in the iodine-bonded molecular conductor (DIETSe)2 FeBr2 Cl2 [DIETSe=diiodo(ethylenedithio)tetraselenafulvalene], which is the first molecular conductor showing a large hysteresis in both magnetic moment and magnetoresistance associated with a spin-flop transition. Utilizing a mixed-anion approach and iodine bonding interactions, we tailored a molecular conductor with random exchange interactions exhibiting unforeseen physical properties.

Effect of database profile variation on drug safety assessment: an analysis of spontaneous adverse event reports of Japanese cases.

BACKGROUND: The use of a statistical approach to analyze cumulative adverse event (AE) reports has been encouraged by regulatory authorities. However, data variations affect statistical analyses (eg, signal detection). Further, differences in regulations, social issues, and health care systems can cause variations in AE data. The present study examined similarities and differences between two publicly available databases, ie, the Japanese Adverse Drug Event Report (JADER) database and the US Food and Drug Administration Adverse Event Reporting System (FAERS), and how they affect signal detection. METHODS: Two AE data sources from 2010 were examined, ie, JADER cases (JP) and Japanese cases extracted from the FAERS (FAERS-JP). Three methods for signals of disproportionate reporting, ie, the reporting odds ratio, Bayesian confidence propagation neural network, and Gamma Poisson Shrinker (GPS), were used on drug-event combinations for three substances frequently recorded in both systems. RESULTS: The two databases showed similar elements of AE reports, but no option was provided for a shareable case identifier. The average number of AEs per case was 1.6±1.3 (maximum 37) in the JP and 3.3±3.5 (maximum 62) in the FAERS-JP. Between 5% and 57% of all AEs were signaled by three quantitative methods for etanercept, infliximab, and paroxetine. Signals identified by GPS for the JP and FAERS-JP, as referenced by Japanese labeling, showed higher positive sensitivity than was expected. CONCLUSION: The FAERS-JP was different from the JADER. Signals derived from both datasets identified different results, but shared certain signals. Discrepancies in type of AEs, drugs reported, and average number of AEs per case were potential contributing factors. This study will help those concerned with pharmacovigilance better understand the use and pitfalls of using spontaneous AE data.

Frameshift mutations produced by 9-aminoacridine in wild-type, uvrA and recA strains of Escherichia coli; specificity within a hotspot.

The endogenous tonB gene of Escherichia coli was used as a target for 9-aminoacridine-induced mutations that were identified in recA(-) and uvrA(-) cells. The cytotoxicity of 9-aminoacridine was enhanced in the uvrA and recA strains compared to the wild-type strain, and the mutagenicity of 9-aminoacridine in the uvrA and recA strains was similar to that in the wild type. For all three strains, the most common mutations were minus frameshifts in repetitive G:C base-pairs followed by minus frameshifts in nonrepetitive G:C base-pairs. 9-aminoacridine-induced minus frameshifts in the wild-type strain were distributed with several hot and warm spots. These sites were also hot and warm spots for minus frameshifts in the recA and uvrA stains. Furthermore, they were hot and warm sites in a 9-aminoacridine-treated strain carrying the target tonB gene oriented in the opposite direction. 9-Aminoacridine is known to interact with DNA to form intercalations which are involved in minus frameshift mutagenesis. In this study, we therefore argue that 1) 9-aminoacridine can induce bulky DNA lesions which are excised by nucleotide excision repair and not involved in mutagenesis, 2) the presence or absence of a recA-dependent repair pathway does not influence the mutagenic effect of 9-aminoacridine, and 3) both leading strand and lagging strand replication equally produce minus frameshifts, therefore gene orientation is not an important determinant of the formation of hot and warm spots by 9-aminoacridine.

Absence of strand bias for deletion mutagenesis during chromosomal leading and lagging strand replication in Escherichia coli.

Investigations were carried out to determine whether both DNA strands involved in Escherichia coli chromosomal DNA replication are replicated with similar accuracy. Experiments consisted of measuring the forward mutation rate from tonB(+) to tonB(-) in pairs of polA deficient strains in which the chromosomal target gene tonB was oriented in the two possible directions relative to the origin of replication, oriC. Within these pairs, the tonB sequence would be subjected to leading strand replication in one orientation and to lagging strand replication in the other. The most common tonB mutations in the polA1 strain were deletions followed by frameshifts. Among the deletions, a strong hotspot site with a 13-base deletion in the polA1 strains accounted for 18 of the 33 deletions in the one orientation, and 31 of the 58 deletions in the other. The results suggested that the two strands were replicated with equal or similar accuracy for deletion formation.