Erratum: Molecular Ion Desorption from LiF(110) Surfaces by Positron Annihilation [Phys. Rev. Lett. 131, 143201 (2023)].

This corrects the article DOI: 10.1103/PhysRevLett.131.143201.

Molecular Ion Desorption from LiF(110) Surfaces by Positron Annihilation.

We have studied the desorption of positive ions from a LiF(110) crystal surface using positron and electron irradiation at 500 eV to examine the interaction between positrons and ionic crystals. Only monatomic ions, such as H^{+}, Li^{+}, and F^{+}, are detected under electron irradiation. However, positron irradiation leads to the significant desorption of ionic molecules, specifically, FH^{+} and F_{2}^{+}. Molecular ion yields are more sensitive to temperature than atomic ion yields. Based on the findings, we propose a desorption model in which positronic compounds are initially produced at the surface and subsequently desorbed as molecular ions via Auger decay following positron annihilation.

Motion-Induced Transition of Positronium through a Static Periodic Magnetic Field in the Sub-THz Region.

Atoms moving in a static periodic field experience a time-dependent oscillating field in their own rest frame. By tuning the frequency, an atomic transition can be induced. So far, this type of transition has been demonstrated in the EUV region or at higher frequencies by crystalline fields and in the microwave region by artificial fields. Here, we present the observation of the transition of positronium (Ps) in the sub-THz region by using an energy-tunable Ps beam with a multilayered magnetic grating. This grating produces a microsized periodic field, whose amplitude corresponds to a huge energy flux of ∼100 MW cm^{-2}, resulting in the efficient magnetic dipole transition.

Quantification of Turbulent Driving Forces for the Geodesic Acoustic Mode in the JFT-2M Tokamak.

We investigate spatial structures of turbulence and turbulent transport modulated by the geodesic acoustic mode (GAM), from which the excitation mechanism of the GAM is discussed. The GAM is found to be predominantly excited through a localized Reynolds stress force, rather than the dynamic shearing force. The evaluated growth rate is larger than the linear damping coefficients and is on the same order of magnitude as the effective growth rate evaluated from time evolution in the GAM kinetic energy.

Synchronization of Geodesic Acoustic Modes and Magnetic Fluctuations in Toroidal Plasmas.

The synchronization of geodesic acoustic modes (GAMs) and magnetic fluctuations is identified in the edge plasmas of the HL-2A tokamak. Mesoscale electric fluctuations (MSEFs) having components of a dominant GAM, and m/n=6/2 potential fluctuations are found at the same frequency as that of the magnetic fluctuations of m/n=6/2 (m and n are poloidal and toroidal mode numbers, respectively). The temporal evolutions of the MSEFs and the magnetic fluctuations clearly show the frequency entrainment and the phase lock between the GAM and the m/n=6/2 magnetic fluctuations. The results indicate that GAMs and magnetic fluctuations can transfer energy through nonlinear synchronization. Such nonlinear synchronization may also contribute to low-frequency zonal flow formation, reduction of turbulence level, and thus confinement regime transitions.

Review of renal anastomosing hemangioma with focus on clinical and pathological aspects.

Renal anastomosing hemangiomas (RAH) has been recently proposed as a new entity. In this article, we summarize the clinicopathologic features of this tumor. RAH usually develops on a background of end-stage renal disease. Macroscopically, tumors are well-defined and their cut surface shows mahogany brown spongy tissue with epicenter in the renal medulla. Tumors are usually small, but larger lesions are reported. On microscopic examination, the tumor consists of sinusoid-like vascular channels lined by cuboidal endothelial cells with occasional hobnail-like appearance of endothelial cells closely mimicking splenic sinusoids. Eosinophilic hyaline globules may be present in the cytoplasm of neoplastic endothelial cells. Extramedullary hematopoiesis containing erythroid precursor and megakaryocytes may be present in the vascular lumens. Immunohistochemically, endothelial cells are positive for CD31 and CD34, but negative for D2-40, GLUT-1 and HHV8. The surrounding stroma around endothelial cells demonstrates positivity for  smooth muscle action. To date, there are no studies on molecular genetic aspects of RAH. This tumor is indolent based on site and size of the lesion, partial or nephrectomy is sufficient as a therapeutic modality.

Characterization of ion-irradiated poly-L-lactic acid using nano-cutting.

Effects on the mechanical strength of poly-L-lactic acid (PLLA) upon irradiation with 150 keV He(+) ion were studied. Changes in the irradiated surface were investigated using a surface texture and contour measuring instrument and an atomic force microscope. Observations made with the atomic force microscope revealed that the irradiated surface subsided significantly as the fluence increased. In order to investigate the dependence on fluence of the depth of the Bragg peak for the ion implantation, the cutting strength, Σ, was analysed [F. Saito, I. Nishiyama and T. Hyodo, Mater. Lett., 2012, 66, 144-146]; this value is an indicator of the strength of a material against cutting, and is obtained from the cutting resistance. The averaged ion projected range increased from about 1.1 µm for a fluence of 1 × 10(15) He(+)/cm(2) to about 4 µm for a fluence of 1 × 10(16) He(+)/cm(2). The density of the region following irradiation was estimated using a combination of cutting resistance measurements and positron annihilation γ ray Doppler broadening measurements made with an energy-variable positron beam. The density decreased from the value of 1.27 g cm(-3) to about 0.6 g cm(-3) after irradiation with a fluence of 3 × 10(15) He(+)/cm(2). By considering the decrease in the density and the subsidence of the surface, it is concluded that only 30% of the original weight remained in the irradiated region after exposure to the He(+) ions. Anisotropic change in the cutting resistance suggests that mechanical strength in the direction normal to the surface increased while that in the lateral direction decreased.

Review of renal tumors associated with Birt-Hogg-Dubé syndrome with focus on clinical and pathobiological aspects.

Birt-Hogg-Dubé syndrome (BHDS) is an autosomal dominant inherited disorder characterized by clinical features of skin lesions, pulmonary lesions and renal tumor. The gene responsible for this syndrome is located on chromosome 17p11.2 and designated as FLCN. In this article, we review renal tumors associated with BHDS with a focus on clinical and pathobiological aspects. Renal tumors often occur multifocally or bilaterally in the imaging analyses or gross examination. Histological examination of renal tumors includes a variety of subtypes such as hybrid oncocytic tumor, chromophobe renal cell carcinoma (RCC), oncocytoma, clear cell RCC and papillary RCC. The histologic discordance in multiple tumors seems to be characteristic of this syndrome. Oncocytosis is observed histologically in about half of the cases. Several investigations have elucidated that folliculin may be involved in the mammalian target of rapamycin (mTOR) pathway recently. Renal tumors composed of clear cells may behave in an aggressive fashion. However, renal tumors including hybrid oncocytic tumor, chromophobe RCC and oncocytoma behave mostly in an indolent fashion.

Metformin prevents liver tumorigenesis induced by high-fat diet in C57Bl/6 mice.

The prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is increasing with the growing epidemics of obesity and diabetes. NAFLD encompasses a clinicopathologic spectrum of disease ranging from isolated hepatic steatosis to NASH, which is a more aggressive form of fatty liver disease, to cirrhosis and, finally, hepatocellular carcinoma (HCC). The exact mechanism behind the development of HCC in NASH remains unclear; however, it has been established that hepatic steatosis is the important risk factor in the development of HCC. Metformin has recently drawn attention because of its potential antitumor effect. Here, we investigated the effects of metformin on high-fat diet (HFD)-induced liver tumorigenesis, using a mouse model of NASH and liver tumor. Metformin prevented long-term HFD-induced liver tumorigenesis in C57Bl/6 mice. Of note, metformin failed to protect against liver tumorigenesis in mice that had already begun to develop NAFLD. Metformin improved short-term HFD-induced fat accumulation in the liver, associated with the suppression of adipose tissue inflammation. Collectively, these results suggest that metformin may prevent liver tumorigenesis via suppression of liver fat accumulation in the early stage, before the onset of NAFLD, which seems to be associated with a delay in the development of inflammation of the adipose tissue.

Spatiotemporal structures of edge limit-cycle oscillation before L-to-H transition in the JFT-2M tokamak.

In this Letter, we report analyses of spatiotemporal dynamics of turbulence and structure in the limit-cycle oscillation (LCO) that precedes an L-to-H transition. Zonal flows are not observed during LCO, and the oscillation is the periodic generations or decays of barrier with edge-localized mean flow. Oscillatory Reynolds stress is found to be too small to accelerate the LCO flow, by considering the dielectric constant in magnetized toroidal plasmas. Propagation of changes of the density gradient and turbulence amplitude into the core is also observed.

Review of tubulocystic carcinoma of the kidney with focus on clinical and pathobiological aspects.

Tubulocystic carcinoma of the kidney (TCK) is a recently established entity in renal neoplastic pathology. This review aims to give an overview of the clinical and pathobiological aspects of TCK. Grossly, the TCKs are well-demarcated multicystic lesions giving a "wrapped bubble" or "spongy" appearance. Microscopically, the tumors are composed of multiple, variably sized cysts separated by thin fibrous septa lacking ovarian stroma or desmoplastic reaction. The cysts are lined by tumor cells with eosinophilic cytoplasm and nuclear atypia of variable, but not infrequently of high grade corresponding to Fuhrman grade 3. A frequent association with papillary tumors has been reported. Recent molecular genetic studies of TCK have revealed distinct features separating this subset of renal cell carcinomas (RCCs) from other types of renal tumors including collecting duct carcinoma of Bellini and renal medullary carcinoma as well as pointing towards a close kinship with papillary RCC. Tubulocystic carcinoma of the kidney generally pursues an indolent clinical course. However, several cases with aggressive clinical behavior have been reported. We strongly feel that there is enough clinicopathological evidence to corroborate TCK as a separate entity and that it should be incorporated into the next WHO classification of renal tumors as a separate neoplastic category.

Protection from non-alcoholic steatohepatitis and liver tumourigenesis in high fat-fed insulin receptor substrate-1-knockout mice despite insulin resistance.

AIMS/HYPOTHESIS: Epidemiological studies have revealed that obesity and diabetes mellitus are independent risk factors for the development of non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma. However, the debate continues on whether insulin resistance as such is directly associated with NASH and liver tumourigenesis. Here, we investigated the incidence of NASH and liver tumourigenesis in Irs1 ( -/- ) mice subjected to a long-term high-fat (HF) diet. Our hypothesis was that hepatic steatosis, rather than insulin resistance may be related to the pathophysiology of these conditions. METHODS: Mice (8 weeks old, C57Bl/6J) were given free access to standard chow (SC) or an HF diet. The development of NASH and liver tumourigenesis was evaluated after mice had been on the above-mentioned diets for 60 weeks. Similarly, Irs1 ( -/- ) mice were also subjected to an HF diet for 60 weeks. RESULTS: Long-term HF diet loading, which causes obesity and insulin resistance, was sufficient to induce NASH and liver tumourigenesis in the C57Bl/6J mice. Obesity and insulin resistance were reduced by switching mice from the HF diet to SC, which also protected these mice against the development of NASH and liver tumourigenesis. However, compared with wild-type mice fed the HF diet, Irs1 ( -/- ) mice fed the HF diet were dramatically protected against NASH and liver tumourigenesis despite the presence of severe insulin resistance and marked postprandial hyperglycaemia. CONCLUSIONS/INTERPRETATION: IRS-1 inhibition might protect against HF diet-induced NASH and liver tumourigenesis, despite the presence of insulin resistance.

Simultaneous evaluation of long-lasting knee synovitis in patients undergoing arthroplasty by power Doppler ultrasonography and contrast-enhanced MRI in comparison with histopathology.

OBJECTIVES: We simultaneously assessed ultrasonography (US) and magnetic resonance imaging (MRI) in comparison with histopathological changes in the knee joints of long-lasting arthritis patients. METHODS: We studied 15 patients with rheumatoid arthritis and 5 patients with osteoarthritis, who underwent total knee arthroplasty. On the day before surgery, the joints were examined by US and contrast-enhanced MRI. In US, synovitis was graded with 0-3 grey scale (GSUS) and power Doppler (PDUS). In MRI, synovitis was graded according to OMERACT-RAMRIS (grade 0-3). Synovial tissue samples were obtained during arthroplasty and evaluated on the basis of inflammatory cell infiltrates (grade 0-3), synovial lining layer thickness (grade 0-3) and vascularity (grade 0-3). RESULTS: Positive findings of PDUS and contrast-enhanced MRI were 45% and 85% of 20 operated joints, respectively. GSUS, PDUS and MRI synovitis were well correlated with overall histopathological grades of synovitis (Spearman correlation coefficients 0.48, 0.84 and 0.48, p<0.05, p<0.01 and p<0.05, respectively). Moreover, positive PDUS findings were closely associated with all pathological comportments of synovitis including inflammatory cell infiltrates, synovial lining layer thickness and vascularity. CONCLUSIONS: The present study revealed that positive PDUS findings more faithfully illustrated active synovitis than MRI, whereas contrast-enhanced MRI was more sensitive in detecting synovitis in patients with long-lasting arthritis. It is important to understand distinct features of the both modalities for clinical assessment of chronic joint diseases.

Conceptual design of a heavy ion beam probe for the QUEST spherical tokamak.

A heavy ion beam probe (HIBP) has been designed for the QUEST spherical tokamak to measure plasma turbulence and the profiles of electric potential profiles. Using a cesium ion beam with an energy of several 10 keV, the observable region covers most of the upper half of the plasma. Although the probe beam is deflected by the poloidal magnetic field produced by plasma current and poloidal coil currents, it can be detected under plasma current up to 150 kA by modifying the trajectories with two electrostatic sweepers. According to the numerical estimation of the intensity of the detected beam, sufficient signal intensity for measuring plasma turbulence can be obtained over almost the measurable area when the electron density is up to 1 × 1019 m-3, which is larger than the cut-off density of electron cyclotron heating in QUEST. The performance of the designed HIBP is sufficient to explore the mechanisms of heat and particle transport in magnetically confined plasmas, including the influence of plasma wall interactions, which is a goal of the QUEST project.

Photodetachment of positronium negative ions.

Photodetachment of the positronium negative ion, a bound state of one positron and two electrons, has been observed. Development of a method to produce the ions efficiently using a Na coated tungsten surface has enabled the first observation of the photodetachment. The obtained lower limit of the photodetachment cross section for the wavelength of 1064 nm is consistent with the theoretical calculations reported so far. The experimental field developed in the present work gives new opportunities to explore the quantum mechanical three-body problem and to develop energy-tunable positronium beams.

Interleukin-18 is elevated in the horny layer in patients with atopic dermatitis and is associated with Staphylococcus aureus colonization.

BACKGROUND: An increase in interleukin (IL)-18 production from epidermal cells has been reported in an atopic dermatitis (AD) mouse model, and subsequent topical application of Staphylococcus aureus results in severe dermatitis. OBJECTIVES: To reveal the relationship between S. aureus colonization of skin lesions and keratinocyte IL-18 production, particularly in AD with relatively low serum IgE levels. We also aimed to establish a simple and noninvasive method of assaying IL-18 produced by epidermal keratinocytes to evaluate local skin inflammation and therapeutic effects in patients with AD. METHODS: IL-18 in the horny layer of the skin was collected via a tape-stripping method and measured in 95 patients with AD and 40 healthy controls by enzyme-linked immunosorbent assay (ELISA). Clinical severity, blood data and S. aureus skin colonization were evaluated before and after treatment. RESULTS: IL-18 levels in the horny layer were significantly higher in the skin lesions of patients with AD than in healthy controls and correlated with SCORAD, levels of serum IL-18, IgE, lactate dehydrogenase, thymus and activation-regulated chemokine, blood eosinophils and transepidermal water loss. In the AD group with serum IgE < 1500 IU mL(-1) , significantly higher IL-18 levels were observed in the horny layer of patients colonized with S. aureus compared with those who were not. CONCLUSIONS: Epidermal IL-18 production was associated with the severity of AD. Staphylococcus aureus colonization seems to contribute to this IL-18 production, especially in the AD group with relatively low IgE production. Tape stripping provides an easy and noninvasive method to assess epidermal IL-18 production by ELISA.

Conceptual design of heavy ion beam probes on the PLATO tokamak.

Heavy ion beam probe (HIBP) systems have been designed for the new tokamak, PLATO [A. Fujisawa, AIP Conf. Proc. 1993, 020011 (2018)]. The designs have been completed, and the installations are in progress. Two HIBPs are being installed in toroidal sections 180° apart to investigate long-range correlations in the toroidal direction. Each HIBP consists of an injection beamline and a detection beamline as usual. Yet, one of the HIBPs is equipped with an additional detection beamline; the measurement positions of its two detection beamlines can be placed on almost the same magnetic surface yet at poloidal angles that differ by ∼180°. The use of three detection beamlines allows us to investigate spatial asymmetry and long-range correlations in both the toroidal and poloidal directions, simultaneously. The detected beam intensity is expected to be enough for turbulence measurements in almost the entire plasma region when the electron density is up to 1 × 1019 m-3 by selecting appropriate ion species for the probe beam. Each detector has three channels 10 mm apart, allowing measurement of local structures of micro-scale turbulence. Therefore, using the HIBPs on the PLATO tokamak will enable both local and global properties of plasma turbulence to be investigated, simultaneously.

Observation of quasi-two-dimensional nonlinear interactions in a drift-wave streamer.

A streamer, which is a bunching of drift-wave fluctuations, and its mediator, which generates the streamer by coupling with other fluctuations, have been observed in a cylindrical magnetized plasma. Their radial structures were investigated in detail by using the biphase analysis. Their quasi-two-dimensional structures were revealed to be equivalent with a pair of fast and slow modes predicted by a nonlinear Schrödinger equation based on the Hasegawa-Mima model.

Synthesis of cold antihydrogen in a cusp trap.

We report here the first successful synthesis of cold antihydrogen atoms employing a cusp trap, which consists of a superconducting anti-Helmholtz coil and a stack of multiple ring electrodes. This success opens a new path to make a stringent test of the CPT symmetry via high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atoms.