Benchmark experiment of large-angle scattering reaction cross section of iron at 14 MeV using two shadow bars – Comparison of experimental results with ENDF/B-VIII –

ABSTRACT

It is important to perform neutron transport simulations with accurate nuclear data in the neutronics design of a fusion reactor. However, absolute values of large-angle scattering cross sections vary among nuclear data libraries even for well-examined nuclide of iron. Benchmark experiments focusing on large-angle scattering cross sections were thus performed to confirm the correctness of nuclear data libraries. The series benchmark experiments were performed at a DT neutron source facility, OKTAVIAN of Osaka University, Japan, by the unique experimental system established by the authors’ group, which can extract only the contribution of large-angle scattering reactions. This system consists of two shadow bars, target plate (iron), and neutron detector (niobium). Two types of shadow bars were used and four irradiations were conducted for one experiment, so that contribution of room-return neutrons was effectively removed and only large-angle scattering neutrons were extracted from the measured four Nb reaction rates. The obtained experimental results were compared with calculations for five nuclear data libraries including JENDL-4.0, JEFF.-3.3, FENDL-3.1, ENDF/B- VII, and recently released ENDF/B-VIII. It was found from the comparison that ENDF/B-VIII showed the best result, though ENDF/B-VII showed overestimation and others are in large underestimation at 14 MeV.     

Ammonia production using iron nitride and water as hydrogen source under mild temperature and pressure

Ammonia generation was studied in the reaction between water and nitrogen-containing iron at 323 K and atmospheric pressure. Similar to metallic Fe, the interstitial compound Fe₃N reduced water through Fe oxidation to produce hydrogen gas, while the N combined with atomic hydrogen to produce ammonia as a byproduct. The addition of carbon dioxide to this system accelerated the reaction with concomitant consumption of carbon dioxide. The promoted ammonia production upon addition of carbon dioxide can be attributed to the generation of atomic hydrogen from the redox reaction of carbonic acid and Fe, as well as removal of used Fe from the reaction system through the formation of a soluble carbonato complex. When carbonate was added to the reaction system, the production rates of ammonia and hydrogen increased further. The results here confirmed that ammonia can be synthesized from iron nitride under mild conditions by utilizing carbon dioxide.     

Molecular Targeted Therapy for the Bone Loss Secondary to Pyogenic Spondylodiscitis Using Medications for Osteoporosis: A Literature Review

Pyogenic spondylodiscitis can cause severe osteolytic and destructive lesions in the spine. Elderly or immunocompromised individuals are particularly susceptible to infectious diseases; specifically, infections in the spine can impair the ability of the spine to support the trunk, causing patients to be bedridden, which can also severely affect the physical condition of patients. Although treatments for osteoporosis have been well studied, treatments for bone loss secondary to infection remain to be elucidated because they have pathological manifestations that are similar to but distinct from those of osteoporosis. Recently, we encountered a patient with severely osteolytic pyogenic spondylodiscitis who was treated with romosozumab and exhibited enhanced bone formation. Romosozumab stimulated canonical Wnt/β-catenin signaling, causing robust bone formation and the inhibition of bone resorption, which exceeded the bone loss secondary to infection. Bone loss due to infections involves the suppression of osteoblastogenesis by osteoblast apoptosis, which is induced by the nuclear factor-κB and mitogen-activated protein kinase pathways, and osteoclastogenesis with the receptor activator of the nuclear factor-κB ligand-receptor combination and subsequent activation of the nuclear factor of activated T cells cytoplasmic 1 and c-Fos. In this study, we review and discuss the molecular mechanisms of bone loss secondary to infection and analyze the efficacy of the medications for osteoporosis, focusing on romosozumab, teriparatide, denosumab, and bisphosphonates, in treating this pathological condition.     

1-GHz-spaced 16-channel arrayed-waveguide grating for a wavelength reference standard in DWDM network systems

We fabricated a 1-GHz-spaced 16-channel arrayed-waveguide grating (AWG) by using a new AWG configuration where the path of each arrayed waveguide winds backward and forward across a 4-in diameter wafer without crossing any other waveguides. The ultra-narrow (< 1 GHz) and stable transmission bands of this AWG can be used to construct a wavelength reference standard covering the S, C, and L bands in the dense wavelength-division-multiplexing network systems whose frequency deviation is /spl plusmn/160 MHz.     

Cover Picture: UV‐Light‐Induced Swelling and Visible‐Light‐Induced Shrinking of a TiO2‐Containing Redox Gel (Adv. Mater. 9/2007)

Polyacrylate gels containing Ag⁺ and TiO₂ nanoparticles are shown to swell under UV light and shrink under visible light in water. In work reported by Tetsu Tatsuma and co‐workers on p. 1249, the TiO₂ absorbs UV light and reduces the Ag⁺, whereas the deposited Ag absorbs visible light and dissolves itself. These redox reactions change the interactions between the polymer chains and eventually the volume of the gel, as shown on the cover.     

Generation of gas bubbles in microflow using micropipette with ultrasound

Ultrasound was applied to a micropipette micromixer to improve dispersion of gas and liquid in a microchannel. Flow visualization using a high-speed camera was performed to examine the effect of ultrasonic irradiation on bubble generation in the microchannel. Basically, nitrogen gas was injected using a (0.5 µm ID) glass micropipette into ethanol flowing in a rectangular (100 µm×200 µm) microchannel on polydimethylsiloxane (PDMS). Gas and liquid flow rates were regulated using mass flow controllers. At aflow condition that is typical of bubbly flow, ultrasound was transmitted into the microchannel using a piezo-electric (PZT) transducer over a range of operating voltages (2 to 200 Vp-p) and frequencies (50 to 60 kHz). Images captured during the action of the PZT transducer indicate that bubble formation is influenced by ultrasound. When subjected to ultrasound above 50 Vp-p and at the resonant frequency of the PZT transducer, bubbles formed that were smaller and closer together, signifying enhanced shearing of the gas at the micropipette tip by the liquid. The observation of gas slugs occurring sooner might be attributed to the coalescence of gas bubbles that became closely spaced.     

Lack of carcinogenicity of medium-viscosity liquid paraffin given in the diet to F344 rats

The carcinogenicity of medium-viscosity liquid paraffin was examined in Fischer 344 rats. Groups of 50 males and 50 females were given the material at dietary doses of 0 (control), 2.5 or 5% for 104 wk. Slight increases in food consumption and body weight were observed in both sexes of the 5% group. However, no significant differences between the control and treated groups were noted with regard to clinical signs, mortality and haematology findings. A variety of tumours developed in all groups, including the control group, but all the neoplastic lesions were histologically similar to those known to occur spontaneously in F344 rats, and no statistically significant increase in the incidence of any tumour type was found for either sex in the treated groups. Granulomatous inflammation in the mesenteric lymph nodes, considered to be a reaction to paraffin absorption, was observed with similar incidence and severity in both sexes of the 2.5 and 5% groups. Thus, it is concluded that under the present experimental conditions, the high dose, about 2000-200,000 times higher than the current temporary acceptable daily intake, does not have any carcinogenic potential in F344 rats. Furthermore, granulomatous inflammation observed in mesenteric lymph nodes were not associated with any development of neoplastic lesions.     

Moisture migration in idealized bilayer systems: relationships among water-associated properties, structure, and texture

The effects of composition and thermal treatment on the water sorption and diffusional properties of idealized protein gels arranged in bilayer configurations were determined; these water binding/migration properties were related to the mechanical characteristics of the gels. Samples were prepared from whey protein concentrate (WPC), they consisted of water:WPC ratios of 1.5 to 5.67, and were thermally set for 20–60 min. Moisture migration rates from samples interfaced with filters were determined, as were moisture sorption capacities of samples immersed in water. The physical properties of the gels were assessed by uniaxial compression and microscopy. Results showed that gel strength and consequent extent of protein interaction—as affected by thermal treatment—controlled the ability of the gel structure to absorb water. Sorption was exponentially correlated with gel modulus and linearly correlated with a function of protein content, heating time, and immersion time. Rates of diffusion from interfaced gels were dependent solely on water content. It was concluded that the degree of protein interaction, whether influenced by concentration or thermal treatment, affected network extensibility and thus the capacity of the gels to act as receptors of moisture. Results have implications for the functionality of shelf-stable sandwiches and other multicomponent foods.     

Involvement of brain serotonergic function in lidocaine-induced convulsions in mice

Influences of drug-induced manipulations of central serotonergic function on lidocaine- and pentylenetetrazol (PTZ)-induced convulsions were examined in mice. Agents that suppressed serotonergic transmission increased, whereas drugs that facilitated serotonin (5-HT) function decreased the incidence of lidocaine-induced convulsions. These treatments had similar influences on the incidence of PTZ-induced convulsions. Lidocaine (10(-5)-10(-3) M) reduced the stimulation evoked [3H]5-HT release from cortical slices, followed with an increased spontaneous [3H] overflow at higher concentrations. These results may suggest that brain 5-HT neurons are causally involved as inhibitory neurons in lidocaine-induced convulsions as in the case of PTZ-induced convulsions.     

A 6-ns ECL 100 K I/O and 8-ns 3.3-V TTL I/O 4-Mb BiCMOS SRAM

The authors report a 4 M word×1 b/1 M word×4 b BiCMOS SRAM that can be metal mask programmed as either a 6-ns access time for an ECL 100 K I/O interface to an 8-ns access time for a 3.3-V TTL I/O interface. Die size is 18.87 mm×8.77 mm. Memory cell size is 5.8 μm×3.2 μm. In order to achieve such high-speed address access times the following technologies were developed: (1) a BiCMOS level converter that directly connects the ECL signal level to the CMOS level; (2) a high-speed BiCMOS circuit with low threshold voltage nMOSFETs; (3) a design method for determining the optimum number of decoder gate stages and the optimum size of gate transistors; (4) high-speed bipolar sensing circuits used at 3.3-V supply voltage; and (5) 0.55-μm BiCMOS process technology with a triple-well structure