Electrically driven europium-doped GaN microdisk

For the practical implementation of microdisk resonators as active nanophotonic devices, it is essential that they can be electrically driven. However, it is difficult to inject current in such small-scale devices without severely degrading their optical properties. We demonstrate the successful fabrication of an electrically injected microdisk based on Eu-doped GaN, in which an SiO2 spacer is used to prevent the interaction of the metal contact with the optical resonances. The microdisk shows Eu-related emission upon electrical injection and from the observed resonance peak, a cavity quality (Q)-factor of 3400 is concluded.

First Observation of Electron Scattering from Online-Produced Radioactive Target

We successfully performed electron scattering off unstable nuclei which were produced online from the photofission of uranium. The target ^{137}Cs ions were trapped with a new target-forming technique that makes a high-density stationary target from a small number of ions by confining them in an electron storage ring. After developments of target generation and transportation systems and the beam stacking method to increase the ion beam intensity up to approximately 2×10^{7} ions per pulse beam, an average luminosity of 0.9×10^{26}  cm^{-2} s^{-1} was achieved for ^{137}Cs. The obtained angular distribution of elastically scattered electrons is consistent with a calculation. This success marks the realization of the anticipated femtoscope which clarifies the structures of exotic and short-lived unstable nuclei.

Radiation effects on wild medaka around Fukushima Dai-ichi Nuclear Power Plant assessed by micronucleus assay

Since the Fukushima Dai-ichi Nuclear Power Plant (F1-NPP) accident in 2011, radiation effects on wildlife in the contaminated areas have been a major concern. The outskirts of the F1-NPP are mainly rural areas, where many rice fields, streams and reservoirs are located. We searched for wild medaka (small aquarium fish) around the F1-NPP and found two wild medaka habitats (S1 and S2). S1 is a stream located 4 km from the F1-NPP, where the ambient dose equivalent rate was 0.4-0.9 μSv/h (2013-14), and S2 is a reservoir located 7.5 km from the F1-NPP, where the ambient dose equivalent rate was 9.8-22 μSv/h (2013-14 and 2017-18). Dosimeters were placed for one day at the locations where the medaka were captured, and the absorbed dose rates were estimated. Radiation effects on wild medaka were examined using micronucleus assay between 2013 and 2018. No significant difference in frequency of micronucleated gill cells was observed among the wild medaka from S1, S2 and our cultivated medaka that were used as a control.

Promotion in solid phase reaction of Pt/SiOx bilayer film by electron-orbital-selective-excitation

A thermally impossible positive free energy reaction can proceed by electron-orbital-selective excitation. When the Si 2p core level is photo-excited in Pt/SiO_x bilayer films, Coulomb repulsion at the final two-hole state localized in the valence band by an interatomic Auger transition induces dissociation of the O atom and formation of a Si–Pt bond. Consequently, Pt₂Si silicide is formed by a positive free energy reaction. Under a single particle excitation of the valence band, low probability of the coexistence of the two-hole state for picosecond order suppresses to allow the reaction to proceed.

A thermally impossible positive free energy reaction can proceed by electron-orbital-selective excitation.

Size dependence of quantum efficiency of red emission from GaN:Eu structures for application in micro-LEDs

GaN-based micro-LEDs typically suffer from a size-dependent efficiency due to the relatively long carrier lifetime and sidewall-related recombination effects. We demonstrate that for red-emitting Eu-doped GaN, sidewall-related recombination is hardly an issue for emission efficiency. We determine the photoluminescence quantum efficiency (PL QE) of Eu-related emission as a function of the size of square structures ranging from 3 to 192 µm. With the support of finite-difference time-domain simulations, we show that the light extraction efficiency and material losses are responsible for the decrease in PL QE for large sizes. For sizes smaller than 24 µm, there is an influence of the sidewall-related non-radiative recombination of carriers on the PL QE; however, it is only minor as a result of the limited carrier diffusion lengths in the Eu-doped material. These properties combined with the high efficiency of luminescence indicate the potential of this material for micro-LED applications.

Reduction of respiratory motion artifacts in gadoxetate-enhanced MR with a deep learning-based filter using convolutional neural network

Objectives

To reveal the utility of motion artifact reduction with convolutional neural network (MARC) in gadoxetate disodium–enhanced multi-arterial phase MRI of the liver.

Methods

This retrospective study included 192 patients (131 men, 68.7 ± 10.3 years) receiving gadoxetate disodium–enhanced liver MRI in 2017. Datasets were submitted to a newly developed filter (MARC), consisting of 7 convolutional layers, and trained on 14,190 cropped images generated from abdominal MR images. Motion artifact for training was simulated by adding periodic k-space domain noise to the images. Original and filtered images of pre-contrast and 6 arterial phases (7 image sets per patient resulting in 1344 sets in total) were evaluated regarding motion artifacts on a 4-point scale. Lesion conspicuity in original and filtered images was ranked by side-by-side comparison.

Results

Of the 1344 original image sets, motion artifact score was 2 in 597, 3 in 165, and 4 in 54 sets. MARC significantly improved image quality over all phases showing an average motion artifact score of 1.97 ± 0.72 compared to 2.53 ± 0.71 in original MR images (p < 0.001). MARC improved motion scores from 2 to 1 in 177/596 (29.65%), from 3 to 2 in 119/165 (72.12%), and from 4 to 3 in 34/54 sets (62.96%). Lesion conspicuity was significantly improved (p < 0.001) without removing anatomical details.

Conclusions

Motion artifacts and lesion conspicuity of gadoxetate disodium–enhanced arterial phase liver MRI were significantly improved by the MARC filter, especially in cases with substantial artifacts. This method can be of high clinical value in subjects with failing breath-hold in the scan.

Key Points

• This study presents a newly developed deep learning–based filter for artifact reduction using convolutional neural network (motion artifact reduction with convolutional neural network, MARC).

• MARC significantly improved MR image quality after gadoxetate disodium administration by reducing motion artifacts, especially in cases with severely degraded images.

• Postprocessing with MARC led to better lesion conspicuity without removing anatomical details.

A survey of the implementation status of selected infection control strategies in neonatal intensive care units in Japan

BACKGROUND

Infection control strategies are implemented in all neonatal intensive care units (NICUs); however, the details of the strategies seem to differ among institutions. The purpose of this survey was to investigate the current implementation status of infection control strategies in NICUs in Japan and to identify and recommend appropriate strategies for the prevention of outbreaks in neonatal units.

METHODS

This survey documented the current implementation status and methods of selected infection prevention and control measures (active surveillance cultures and standard precaution) in 453 Japanese NICUs/neonatal units registered with the Japan Society of Perinatal and Neonatal Medicine, using questionnaires, in May 2018.

FINDINGS

The response rate was 48.1% (level I institutions, 25.5%; level II, 55.9%; level III, 64.2%). Surveillance cultures were performed every week and targeted all bacteria in most units. The proportion of level III institutions that experienced outbreaks over the previous five years was significantly higher than that of level II institutions (55% vs 27%, P=0.0003). However, wearing a mask was less frequently recommended in level III institutions (55.7%) than in level II institutions (67.9%). Meticillin-resistant Staphylococcus aureus (MRSA) was the most frequently reported bacterial pathogen responsible for NICU outbreaks.

CONCLUSION

Infection prevention and control practices regarding active pathogen surveillance cultures and the use of barrier precautions varied widely in Japanese neonatal units. National guidelines and evidence-based recommendations are needed to rationalize and standardize current infection prevention and control practices in neonatal units in Japan.

P1956Geriatric nutritional risk index as predictor for long-term survival and cardiovascular or limb events in peripheral arterial disease patients

Background

The geriatric nutritional risk index (GNRI) is a simple tool to assess the nutritional risk and associated with mortality. However, there are no reports focusing GNRI in peripheral artery disease (PAD) patients.

Purpose

The purpose of this study was to examine the effects of GNRI for long-term survival, cardiovascular and limb events in PAD patients.

Methods

A prospective cohort study was performed in 1219 PAD patients. Baseline GNRI was calculated from serum albumin level and body-mass-index. The patients were divided into four groups by GNRI level (G1: >98; G2: 92–98; G3: 82–91; G4: <82). The endpoints were overall survival (OS) and freedom from major adverse cardiovascular and limb events (MACE and MACLE).

Results

The median follow-up was 73 months. There were 626 deaths (51.4%) during follow-up. The rate of cardiovascular death among dead was 51.3%. The OS rates markedly depended on GNRI level (p<0.01). The 5-year OS rates were G1: 80.8%, G2: 62.0%, G3: 40.0%, G4: 23.3%, respectively. In multivariate analyses, GNRI, age, low ankle brachial pressure index (ABI), low estimated glomerular filtration rate (eGFR), and high C-reactive protein (CRP) levels were independent factors associated with OS (<0.05). GNRI, age, low ABI, diabetes mellitus, coronary artery disease, lower eGFR and higher CRP levels were associated with MACE and MACLE (p<0.05, respectively). Besides, statins improved OS, MACE, and MACLE (<0.01, respectively).

Conclusions

GNRI was an independent predictor for OS, MACE, and MACLE in PAD patients. Furthermore,statins improved OS, MACE and MACLE in patients with PAD.

Hepatobiliary phase hypointense nodule without arterial phase hyperenhancement as a risk factor for late recurrence (>1 year) of hepatocellular carcinoma after surgery

AIM

To evaluate the value of magnetic resonance imaging (MRI) features, including liver stiffness measured by magnetic resonance elastography (MRE) and the presence of hepatobiliary phase (HBP) hypointense nodule without arterial phase hyperenhancement (APHE), for predicting late recurrence (>1 year) after surgery for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This retrospective study included 124 consecutive patients who had undergone surgery for HCC and preoperative MRI. After excluding patients with early recurrence within 1 year after surgery, 89 patients were analysed. Preoperative MRI images were reviewed by a radiologist to record imaging findings, including (1) liver stiffness by MRE, (2) size of the HCCs, (3) number of HCCs, and (4) presence of HBP hypointense nodule without APHE. Pathological findings included tumour grade, vascular/biliary/capsule invasion, and fibrosis stage of the liver. Considering imaging/pathological findings and patients' characteristics as dependent variables, Cox proportional hazards model analysis was performed to identify independent factors associated with late recurrence after surgery.

RESULTS

The median follow-up period was 37.3 months. During follow-up, 29 patients (32.5%) developed late recurrence after surgery. In multivariate analysis, underlying liver disease (viral hepatitis) and presence of HBP hypointense nodules without APHE (p=0.010 and 0.033, respectively) were independently associated with disease-free survival (DFS). Kaplan-Meier analysis revealed that patients with HBP hypointense nodules without APHE had a significantly lower DFS rate than those without the nodule (39.2% versus 74.1% at 3 years after surgery, p=0.008).

CONCLUSION

The presence of HBP hypointense nodules without APHE was an indicator of late recurrence after surgery for HCC.

Hyperphosphatemic familial tumoral calcinosis secondary to fibroblast growth factor 23 (FGF23) mutation: a report of two affected families and review of the literature

Hyperphosphatemic familial tumoral calcinosis (HFTC), secondary to fibroblast growth factor 23 (FGF23) gene mutation, is a rare genetic disorder characterized by recurrent calcified masses. We describe young Lebanese cousins presenting with HFTC, based on a retrospective chart review and a prospective case study. In addition, we present a comprehensive review on the topic, based on a literature search conducted in PubMed and Google Scholar, in 2014 and updated in December 2017. While the patients had the same previously reported FGF23 gene mutation (homozygous c.G367T variant in exon 3 leading to a missense mutation), they presented with variable severity and age of disease onset (at 4 years in patient 1 and at 23 years in patient 2). A review of the literature revealed several potential patho-physiologic pathways of HFTC clinical manifestations, some of which may be independent of hyperphosphatemia. Most available treatment options aim at reducing serum phosphate level, by stimulating renal excretion or by inhibiting intestinal absorption. HFTC is a challenging disease. While the available medical treatment has a limited and inconsistent effect on disease symptomatology, surgical resection of calcified masses remains the last resort. Research is needed to determine the safety and efficacy of FGF23 replacement or molecular therapy, targeting the specific genetic aberration. Hyperphosphatemic familial tumoral calcinosis is a rare genetic disorder characterized by recurrent calcified masses, in addition to other visceral, skeletal, and vascular manifestations. It remains a very challenging disease.

Size-dependent uptake of electrically neutral amphipathic polymeric nanoparticles by cell-sized liposomes and an insight into their internalization mechanism in living cells

The size-dependent uptake of amphipathic uncharged-nanoparticles in cell-sized liposomes is emerging as a new insight into their internalization mechanism in living cells.

Impact of the structures of macrocyclic Michael acceptors on covalent proteasome inhibition

A systematic analysis of the structure–activity relationship of a series of syringolin analogues, which are irreversible covalent inhibitors of proteasomes.

Molecules that have a reactive functional group within a macrocycle represent a class of covalent inhibitor. The relationship between reactivity and affinity for the target is cooperative and complicated. An understanding and characterization of this class of inhibitor are vital for the development of covalent inhibitors as drug candidates. Herein, we describe a systematic analysis of structure–activity relationships using a series of syringolin analogues, which are irreversible covalent inhibitors of proteasomes. We investigate the detailed mechanistic effects of the macrocycles on affinity and reaction rate.

First Elastic Electron Scattering from ^{132}Xe at the SCRIT Facility

The first elastic electron scattering has been successfully performed at the self-confining radioactive-isotope ion target (SCRIT) facility, the world's first electron scattering facility for SCRIT technique achieved high luminosity (over 10^{27}  cm^{-2} s^{-1}, sufficient for determining the nuclear shape) with only 10^{8} target ions. While ^{132}Xe used in this time as a target is a stable isotope, the charge density distribution was first extracted from the momentum transfer distributions of the scattered electrons by comparing the results with those calculated by a phase shift calculation.

Antibacterial Nucleoside Natural Products Inhibiting Phospho-MurNAc-Pentapeptide Translocase; Chemistry and Structure-Activity Relationship

The continued emergence of drug-resistance to existing antibacterial agents represents a severe and ongoing public health concern, which demands the discovery of new antibiotics. However the number of novel classes of antibacterial drugs launched in the clinic has been remarkably slow since the 1960s, and it is urgent to develop novel antibacterial agents to fight against drug-resistant bacterial pathogens. Peptidoglycan is a component of the bacterial cell wall, which consists of a repeated N-acetylmuramic acid (MurNAc) and Nacetylglucosamine (GluNAc) polymer cross-linked with polypeptides, and is a good target for antibacterial drug discovery. Among enzymes responsible for its biosynthesis, phospho-MurNAc-pentapeptide translocase (MraY) is a novel and promising target. Many nucleoside natural products, which strongly inhibit MraY, have been found in nature. This review will summarize the synthesis and biological properties of selected MraY inhibitory nucleoside natural products and their analogues synthesized in our laboratory and by others.

Effect of Antihypertensive Therapy on Blood Rheology in Patients with Essential Hypertension

Hypertension is an important risk factor for cardiovascular disease, and antihypertensive drugs can decrease the occurrence of such events in hypertensive patients. This study compared the rheological properties of blood in 22 untreated hypertensive patients, 42 patients taking antihypertensive drugs and 74 normotensive subjects. Using a microchannel method, the whole blood passage time was measured and blood movement was observed with a microscope connected to an image display unit. The blood passage time in untreated hypertensive patients was significantly higher than in treated hypertensive patients or normotensive subjects, but was similar in the latter two groups. Microscopic observations showed that platelet aggregation and leucocyte adhesion were increased in untreated hypertensive patients, resulting in poor flow, while blood samples from treated hypertensive patients and normotensive subjects passed smoothly through the microchannels. These rheological differences could contribute to the decrease in cardiovascular disease seen when hypertensive patients are treated effectively.

Evaluation of floating impeller phenomena in a Gyro centrifugal pump

The Gyro centrifugal pump developed as a totally implantable artificial heart was designed with a free impeller, in which the rotational shaft (male bearing) of the impeller was completely separated from the female bearing. For this type of pump, it is very important to keep the proper magnet balance (impeller-magnet and actuator-magnet) in order to prevent thrombus formation and/or bearing wear. When the magnet balance is not proper, the impeller is jerked down into the bottom bearing. On the other hand, if magnet balance is proper, the impeller lifted off the bottom of the pump housing within a certain range of pumping conditions. In this study, this floating phenomenon was investigated in detail. The floating phenomenon was proved by observation of the impeller behavior using a transparent acrylic pump. The impeller floating phenomenon was mapped on a pump performance curve. The impeller floating phenomenon is affected by the magnet-magnet coupling distance and rotational speed of the impeller. In order to keep the proper magnet balance and to maintain the impeller floating phenomenon at the driving condition of right and left pump, the magnet-magnet coupling distance was altered by a spacer which was installed between the pump and actuator. It became clear that the same pump could handle different conditions (right and left ventricular assist), by just changing the thickness of the spacer. When magnet balance is proper, the floating impeller phenomenon occurs automatically in response to the impeller rev. It is called "the dynamic RPM suspension".

Wall-loss distribution of charge breeding ions in an electron cyclotron resonance ion source

We investigated the ion-loss distribution on the sidewall of an electron cyclotron resonance (ECR) plasma chamber using the 18-GHz ECR charge breeder at the Tokai Radioactive Ion Accelerator Complex (TRIAC). Similarities and differences between the ion-loss distributions (longitudinal and azimuthal) of different ion species (i.e., radioactive (111)In(1+) and (140)Xe(1+) ions that are typical volatile and nonvolatile elements) was qualitatively discussed to understand the element dependence of the charge breeding efficiency. Especially, the similarities represent universal ion loss characteristics in an ECR charge breeder, which are different from the loss patterns of electrons on the ECRIS wall.

Wall-loss distribution of charge breeding ions in an electron cyclotron resonance ion source

The ion loss distribution in an electron cyclotron resonance ion source (ECRIS) was investigated to understand the element dependence of the charge breeding efficiency in an electron cyclotron resonance (ECR) charge breeder. The radioactive (111)In(1+) and (140)Xe(1+) ions (typical nonvolatile and volatile elements, respectively) were injected into the ECR charge breeder at the Tokai Radioactive Ion Accelerator Complex to breed their charge states. Their respective residual activities on the sidewall of the cylindrical plasma chamber of the source were measured after charge breeding as functions of the azimuthal angle and longitudinal position and two-dimensional distributions of ions lost during charge breeding in the ECRIS were obtained. These distributions had different azimuthal symmetries. The origins of these different azimuthal symmetries are qualitatively discussed by analyzing the differences and similarities in the observed wall-loss patterns. The implications for improving the charge breeding efficiencies of nonvolatile elements in ECR charge breeders are described. The similarities represent universal ion loss characteristics in an ECR charge breeder, which are different from the loss patterns of electrons on the ECRIS wall.

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

The catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

Mean Inner Potential of Nanostructured Noble Metal Catalysts - Pt/TiO2 Catalyst -

Catalytic properties of noble metal catalysts are often caused by their nanostructures. Gold catalysts are typical cases. It is especially interesting that the catalytic property of gold suddenly changes to resemble that of platinum when the mean size of gold dispersed on certain oxides is <2nm. This phenomenon should be owing to the change of the local electronic structure of the gold particle or the interface between the gold and the oxides, however its detail has not been cleared yet. We measured the mean inner potential of gold particles supported on TiO2 using electron holography and HREM, and found that the mean inner potential of gold depend largely on the size of the gold particles. When the size is >5nm, the mean inner potential is the same as the reported values of bulk gold (experimental: 21–23V, calculated: 25–30V). When the size is <5nm, it begins to increase >30V, and it begins to increase suddenly >40V at the size <2nm. It indicates that the electronic structure of the gold particle varies from that of the bulk state as the size of the gold reduces due to the nano-size effect or the interaction at the interface, since the mean inner potential is sensitive to the electronic state of the outer valence electron. On the other hand, the behavior of the platinum catalysts is different from that of gold catalysts. When the size of the platinum particle on the TiO2 support is >1.5nm, the mean inner potential of platinum is the same as that of the bulk (∼25V). In case of the particle with the size <1.5nm, it begins to increase and the increase rate is lower than that of the gold particles with the size <2nm. It is suggested to be due to the difference of the interaction with TiO2.

Development of radioactive ion beam production systems for Tokai Radioactive Ion Acceleration Complex-High temperature ion source for short-lived isotopes

We have developed a new ion source system in the isotope separator on-line at Japan Atomic Energy Agency, for separation of short-lived isotopes produced by proton-induced fission of (238)U. The ion source system is a forced electron beam induced arc discharge version E type ion source with a target container. We successfully operated this system at 2000 degrees C as a result of reductions in volume of the ion source and the target container, introduction of heating method by electron bombardment, and improvement to the heat shield. This new ion source system was tested using (238)U of 640 mg/cm(2) with a proton primary beam of 30 MeV, 350 nA. Release times were measured for Kr, In, and Xe. The values of release times are 2.6 s for Kr, 1.8 s for In, and 4.6 s for Xe. In this work, the ion source system enabled us to mass-separate short-lived isotopes such as (93)Kr(T(1/2)=1.286 s), (129)In(T(1/2)=0.61 s), and (141)Xe(T(1/2)=1.73 s) with intensity of 10(3) ions/s.

Extraction behavior of rutherfordium into tributylphosphate from hydrochloric acid

The extraction behavior of rutherfordium (Rf) into tributylphosphate (TBP) from hydrochloric acid (HCl) has been studied together with those of the lighter group-4 elements Zr and Hf. The extractability of261Rf,169Hf, and85Zr into TBP was investigated under identical conditions in 7.2–8.0 M HCl by on-line reversed-phase extraction chromatography. The percent extractions of Rf, Hf, and Zr into the TBP resin increase steeply with increasing HCl concentration, and the order of extraction is Zr > Hf ≈ Rf. By considering the order of chloride complexation among these elements, it is suggested that the stability of the TBP complex of Rf tetrachloride is lower than those of Zr and Hf.

Startup of transactinide chemistry in JAERI

The transactinide nuclides261Rf and262Db have been successfully produced in the248Cm(18O,5n) reaction at 99 MeV and in the248Cm(19F,5n) reaction at 100, 103, and 106 MeV, respectively, at the JAERI tandem accelerator. The on-line ion exchange experiments with an automated fast and repetitive liquid chromatography separation system were performed in the HNO3/HF system using Rf homologues89mZr and167,165Hf produced in the89Y(p,n) and152Gd(18O,xn) reactions, respectively. The radiotracers88Zr,175Hf, and234Th were also prepared and the distribution coefficients on ion exchange resins were measured systematically in 1-11 M HCl and 1-14 M HNO3with the batch method. It was found that anion exchange experiments of Rf in 8 M HNO3and 9 M HCl provided information useful to extract the ionic radius of Rf and to verify the influence of relativistic effects.

Converting an insulating silicon nanochain to a conducting carbon nanotube by electrical breakdown

Electrical breakdowns of individual silicon nanochains, in which silicon nanoparticles are covered with and connected by oxide alternatively forming nanowires, are studied by in situ transmission electron microscopy using a microprobe system. Individual silicon nanochains can endure a current typically as large as 10(0) nA, and we found that a silicon nanochain can be converted to a nanotube by applying a current as large as 10(1) nA. In the nanotubes, some silicon particles are left. Experimental results suggest that nanotubes are heavily distorted carbon nanotubes, which are formed through the aggregation of contaminating carbon on the nanochain surface and the evaporation of the oxide core due to Joule heating.

Association studies of ALOX5 and bone mineral density in healthy adults

Animal studies suggest that arachidonate 5-lipoxygenase (encoded by ALOX5) may be a genetic determinant of bone mineral density. We tested this hypothesis in a sample of healthy men and women and did not find consistent evidence for an association between variation in this gene and either lumbar spine or femoral neck BMD.

INTRODUCTION

Phenotypic variation in bone mineral density (BMD) among healthy adults is influenced by both genetic and environmental factors. A recent mouse study implicated ALOX5, which encodes arachidonate 5-lipoxygenase, as a contributing factor to areal BMD (aBMD).

METHODS

Fifteen single nucleotide polymorphisms (SNPs) distributed throughout ALOX5 were genotyped in three healthy groups: 1,688 European American, premenopausal sisters, 512 African American premenopausal sisters and 715 European American brothers. Statistical analyses were performed in the three groups to test for association between these SNPs and femoral neck and lumbar spine aBMD.

RESULTS

Significant (p < or = 0.05) evidence of association was observed with three of the SNPs. However, despite the linkage disequilibrium between SNPs, adjacent SNPs did not provide statistical evidence of association in any of the three study groups.

CONCLUSIONS

These data do not provide consistent evidence of association between genomic variation in ALOX5 and clinical variability in aBMD in healthy subjects.

KEKCB electron cyclotron resonance charge breeder at TRIAC

The KEKCB is an electron cyclotron resonance (ECR) ion source for converting singly charged ions to multicharged ones at Tokai Radioactive Ion Accelerator Complex. By using the KEKCB, singly charged gaseous and nongaseous ions were converted to multicharged ones of A/q approximately 7 with efficiencies of 7% and 2%, respectively. The conversion efficiency was found to be independent of the lifetime of the radioactive nuclei having lifetimes of the order of one second. Three collimators located at the entrance and the exit of the KEKCB defined the beam axis and facilitated beam injection. Grinding and washing the surfaces of aluminum electrode and plasma chamber dramatically reduced impurities originating from the ECR plasma of the KEKCB.

Chemical studies on rutherfordium (Rf) at JAERI

Chemical studies on element 104, rutherfordium (Rf), at JAERI (Japan Atomic Energy Research Institute) are reviewed. The transactinide nuclide261Rf has been produced in the reaction248Cm(18O, 5n) at the JAERI tandem accelerator with the production cross section of about 13 nb. On-line anion-exchange experiments on Rf together with the lighter homologues, group-4 elements Zr and Hf, in acidic solutions have been conducted with a rapid ion-exchange separation apparatus. From the systematic study of the anion-exchange behavior of Rf, it has been found that the properties of Rf in HCl and HNO3solutions are quite similar to those of Zr and Hf, definitely confirming that Rf is a member of the group-4 elements. However, we have observed an unexpected chemical behavior of Rf in HF solutions; the fluoride complex formation of Rf is significantly different from those of the homologues. Prospects of extending chemical studies on transactinide elements in the near future at JAERI are briefly considered.