Search

18th EISCAT symposiumSession E3: Ionoshere/thermosphere/mesosphereMay 27 (Sat), NIPR Auditorium

Hyperpolarized (HP) gas magnetic resonance imaging (MRI) is an imaging modality that exploits the ability of stable spin ½ noble gases, such as 129 Xe and 3 He to be polarized, allowing an increase in their nuclear magnetic resonance signal-to-noise ratio of up to five orders of magnitude over their thermal equilibrium polarization. This allows for the detection and imaging of these gases at concentrations of up to four orders of magnitude lower than the tissue water proton concentration used for conventional 1 H imaging. In this chapter, we review the state-of-the-art of HP 129 Xe MRI when used for brain imaging. We briefly cover existing brain imaging techniques and their relative advantages and disadvantages. The relevant properties of 129 Xe as applied to MR are discussed. A major focus of this chapter is on the potential medical applications of HP 129 Xe MRI, including stroke and functional brain imaging.

Mice have been commonly used for different purposes in a variety of preclinical studies, mainly because of the availability of a wide range of disease models as well as genetically altered animals. It is, however, necessary to develop elemental technology that is optimized for mouse-specific measurements to achieve a successful outcome from magnetic resonance (MR) studies using hyperpolarized (HP) noble gases (e.g., 129 Xe and 3 He). In this chapter, we provide a brief overview of the recent progress made by our group in the development of HP 129 Xe MR measurements at 9.4 Tesla. Our research focuses on HP 129 Xe MR spectroscopy and imaging in mice that spontaneously inhale the HP 129 Xe continuously delivered from a hyperpolarizer. This simple and noninvasive protocol allows us to perform HP 129 Xe MR studies in mice under natural physiological conditions. Some successful examples of this protocol are summarized in assessing physiological conditions related to pulmonary functions.

This paper presents a novel failure prediction technique that is applicable for system-on-chips (SoCs). Highly reliable systems such as automobiles, aircrafts, or medical equipments would not allow any interruptive erroneous responses during system operations, which might result in catastrophes. Therefore, we propose a failure prediction technique that can be applied during an idle time when a system is not working, such as power-on/-off time. To achieve high reliability in the field, the proposed technique should take into consideration various types of aging mechanisms and the testing environment of voltage and temperature which is uncontrollable in the field. Therefore, we propose: 1) an accurate delay measurement technique considering the variation due to voltage and temperature and 2) an adaptive test scheduling that gives more test chances to more probable degrading parts. Experimental results show the required memory space and area cost for implementing the proposed technique.

Recent climate change, especially during the 2000s, may be the primary reason for the expansion of the Asian dust source region. The change in the dust source region was investigated by examining anthropogenic radionuclides contained in surface soil samples from Mongolia. Surface soil was globally labeled by radioactive fallout from nuclear testing during the late 1950s and early 1960s, but there are no current direct sources for anthropogenic radionuclides in the air (before the Fukushima nuclear power plant accident in 2011). Radionuclides in the atmosphere are therefore carried mainly by wind-blown dust from surface soil, that is, aeolian dust. Asian dust carries traces of 90Sr, 137Cs, and other anthropogenic radionuclides; the heaviest deposition occurs in spring and has been recorded in Japan since the early 1990s. The composition of anthropogenic radionuclides in atmospheric depositions would be affected by a change in the dust source. Previous studies of atmospheric deposition at long-term monitoring sites (e.g. in Tsukuba, Japan) have detected changes in the 137Cs/90Sr ratio and in the specific activity of the radionuclides. These changes in the composition of observed atmospheric depositions are supposed to reflect changes in the climatic conditions of the dust source region. To investigate this dust source change, we conducted a field survey of radionuclides (90Sr and 137Cs) in surface soil samples in September 2007 in the eastern and southern regions of Mongolia, where dust storms have occurred more frequently since 2000. The specific activities of both radionuclides as well as the 137Cs/90Sr ratio in the surface soil were well correlated with annual average precipitation in the Mongolian desert-steppe zone. Higher specific activities and a higher 137Cs/90Sr ratio were found in grassland regions that experienced greater precipitation. These findings suggest that the increased specific activities and the activity ratio detected in atmospheric depositions in Japan during years with frequent Asian dust transport events in the 2000s are a sign of grassland degradation.

The purpose of this investigation was to study the effects of renal function on the pharmacokinetics and pharmacodynamics (PK-PD) of free cefazolin administered prophylactically in cardiothoracic surgery. Patients received an initial 2-g dose of cefazolin, followed by 1-g doses 6, 12, 18 and 24 h after the first dose. In patients who underwent cardiopulmonary bypass, 1 g was added to the priming solution. In 35 patients with a normal estimated creatinine clearance (CLcr) ≥50 ml/min, a free cefazolin concentration

Consumption of coal is increasing as an alternative for petroleum. During the process, coal fly ash particles are produced and are disposed as an industrial waste. Coal ash contains toxic heavy metals, which leads to a concern about the possibility of leakage into environment. The spatial distribution and chemical form as well as elemental concentration of the toxic elements in the particles are important factors in assessing the leakage into the environment. In this study, we analyzed individual coal fly ash particles with 1 µm spatial resolution by using the simultaneous micro-PIXE/RBS/off-axis STIM system at Tohoku University. Eighty fly ash particles were analyzed. The particles are mainly composed of O , Si and Al and estimated as dioxide. Hydrogen and carbon are not observed in these particles. V , Zn , Sr , Cu , Ni , Mn , Cr and As are contained in the particles. The content of each element is quite different in each particle. These elements are distributed homogeneously. As an exception, Al , Ca , Fe , Zn , As and Zr are distributed on the surface of the particle which might be related to the combustion process.

In order to assess the effect of marine and terrestrial environmental change in the last decades on the sedimentation environment in Ariake Bay, we collected three sediment cores. The concentrations of natural and anthropogenic radionuclides, major elements, and rare-earth elements were measured using gamma-spectrometry and neutron activation analysis. Vertical distributions of both radionuclides and sedimentation rates, determined using Cs-137 and Pb-210ex dating methods, varied significantly among the sites.

Following transection of the spinal cord, severed axonal ends retract from the lesion site and attempt regeneration within 24 h of injury. Molecular mechanisms underlying such rapid axonal reactions after severance are not fully characterized so far. To better understand the early axonal degenerating and regenerating processes, we examined the immunohistological expression of axonal cytoskeletal proteins from 5 min to 48 h after scalpel-transection of adult rat spinal cord white matter. Within 30 min of transection, expression of neurofilament (NF)- and peripherin-like immunoreactivity (-IR) was enhanced in severed axonal ends, which conversely lost beta-III-tubulin-IR expression, indicating differential expression of beta-III-tubulin-IR and NF/peripherin-IR. During the next few hours, the strongly-NF/peripherin-IR-positive severed axonal ends adhered to each other and these cytoskeletal alterations expanded bi-directionally (rostro-caudally) 100–300 μm away from the transection point. Within 6 h of transection, secondary axotomy occurred at about 300 μm-rostral and -caudal to the primary transection point, which finally formed strongly-NF/peripherin-IR-positive zipper-like axon segments at the transection site. Notably, sprouting of secondarily severed axons was observed within 6 h of injury. The regenerative axons, which extended toward the transection site, could not traverse the transection site where the zipper-like axon segments resided. The zipper-like axon segments showed abnormal axolemmal permeability through the leakage of an axonal tracer. Western blot analysis revealed a slight increase in peripherin content in transected spinal cord. Local treatment with cycloheximide suppressed the axotomy-induced peripherin-IR-enhancement in severed ends, suggesting the occurrence of intra-axonal peripherin synthesis in vivo . Treatment with calpain inhibitors frequently formed abnormally swollen microtubule-free ends, which suggests that calpain-activation is critical for functional growth cone formation in adult rat spinal cord. These observations indicate that adult rat cordotomy with a scalpel results in the rapid formation of intensely NF-IR-positive zipper-like axon segments at the transection site, which are similar to “ preserved fibers ” reported by Ramon y Cajal [ Ramon y Cajal S (1928) Degeneration and regeneration in the nervous system. New York: Hafner]. On the other hand, axonal regenerative responses start within 6 h of injury, which may be supported by calpain-activation and intra-axonal protein synthesis.

A transient grating study of intermolecular vibrational energy dissipation in competition with intramolecular vibrational energy re-distribution (IVR) is reported. The translational temperature rise rates of 1-alkylazulene and 1-(anthracene-9-yl-alkyl)azulene in organic solvents are compared with the kinetics obtained from transient absorption (TA) experiments [D. Schwarzer, P. Kutne, C. Schroder, J. Troe, J. Chem. Phys. 121 (2004) 1754]. The results of 1-alkylazulene suggest the dynamics assigned to IVR in the TA study could complete with the temperature rise kinetics of the solvent. The results of 1-(anthracene-9-yl-alkyl)azulene support the existence of the faster dissipation process than TA component. The different solvent effects are also discussed.

The alignment correlation term in the β-ray angular distribution from purely nuclear spin aligned 20F has been measured to test the G-parity conservation law which is one of the fundamental symmetries in the weak nucleon current. We utilized the hyperfine interaction of 20F in an MgF2 single crystal and successfully created the pure alignment from the polarization by means of the spin manipulation technique based on the β-NMR method.

A two-stage scan architecture is proposed to constrain transition propagation within a small part of scan flip-flops. Most scan flip-flops are deactivated during test application. The first stage includes multiple scan chains, where each scan chain is driven by a primary input. Each scan flip-flop in the multiple scan chains drives a group of scan flip-flops in the second stage. Scan flip-flops in different stages use separate clock signals. Test signals assigned to scan flip-flops in the multiple scan chains are applied to the scan flip-flops of the second stage in one clock cycle after the test vector has been applied to the multiple scan chains. There exists no transition at the scan flip-flops in the second stage when a test vector is applied to the multiple scan chains

Plutonium (

We investigated the role of inositol 1,4,5-trisphosphate receptors (IP3Rs) activated during preconditioning low-frequency stimulation (LFS) in the subsequent high-frequency stimulation (HFS)-induced induction of long-term potentiation (LTP) in CA1 neurons in hippocampal slices from mature guinea pigs. Induction of LTP in the field excitatory postsynaptic potential (EPSP) or the population spike (PS) by delivery of HFS (a tetanus of 100 pulses at 100 Hz) to the Schaffer collateral-commissural pathway to CA1 neuron synapses was suppressed when the CA1 synapses were preconditioned by LFS of 1000 pulses at 1 Hz. This effect was inhibited when the preconditioning LFS was applied in the presence of an N-methyl-D-aspartate receptors (NMDARs) antagonist, a metabotropic glutamate receptor (mGluR) antagonist, IP3R antagonist, a calmodulin-dependent kinase II inhibitor or a calcineurin inhibitor. Furthermore, blockade of group I mGluRs immediately before the delivery of HFS blocked the inhibitory effect of the preconditioning LFS on subsequent induction of LTP by HFS. These results suggest that, in hippocampal CA1 neuron synapses, co-activation of NMDARs and IP3Rs during a preconditioning LFS results in both phosphorylation and dephosphorylation events that lead to prolonged activation of group I mGluRs that is responsible for the failure of LTP induction.

Aims In this prospective observational study, we investigated the time-dependent changes and correlations of upper arm performance tests (ten-second test and Simple Test for Evaluating Hand Function (STEF), the Japanese Orthopaedic Association (JOA) score, and the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) in 31 patients with cervical myelopathy who had undergone surgery. Patients and Methods We hypothesised that all the indices correlate with each other, but show slightly different recovery patterns, and that the newly described JOACMEQ is a sensitive outcome measure. Results Peak recoveries were achieved one month post-operatively in the ten-second test and JOACMEQ upper extremity function (UEF) subscale, and at three months in the JOA and STEF scores. The recoveries of all indices were maintained until six months post-operatively. The upper extremity function (UEF) subscale in the JOACMEQ showed the strongest correlation with STEF although all the indices correlated with each other. Patients with ≥ 20 and < 20 acquired points in the UEF subscale were classified into the UEF-improved and UEF-unimproved groups. Comparisons between the groups showed that pre-operative evaluation of “coordinated motion” of the STEF was significantly low in the UEF-unimproved group. Conclusion These results indicate that the JOACMEQ is a concise, sensitive, patient-based outcome measure for evaluating functional recovery in patients with cervical myelopathy who have undergone surgery. Cite this article: Bone Joint J 2016;98-B:990–6.

We have investigated the efficiency and limits of polarization dependent hard X-ray photoelectron spectroscopy (HAXPES) in order to establish how well this method can be used to unravel quantitatively the contributions of the orbitals forming the valence band of solids. By rotating the energy analyzer rather than the polarization vector of the light using a phase retarder, we obtained the advantage that the full polarization of the light is available for the investigation. Using NiO, ZnO, and Cu2O as examples for solid state materials, we established that the polarization dependence is much larger than in photoemission experiments utilizing ultra-violet or soft X-ray light. Yet we also have discovered that the polarization dependence is less than complete on the basis of atomic calculations, strongly suggesting that the trajectories of the outgoing electrons are affected by appreciable side-scattering processes even at these high kinetic energies. We have found in our experiment that these can be effectively described as a directional spread of +/- 18 degrees of the photoelectrons. This knowledge allows us to identify, for example, reliably the Ni 3d spectral weight of the NiO valence band and at the same time to demonstrate the importance of the Ni 4s for the chemical stability of the compound. (C) 2014 Elsevier B.V. All rights reserved.

The 256-slice CT-scanner has been developed at National Institute of Radiological Sciences. Nominal beam width was 128 mm in the longitudinal direction. When scanning continuously at the same position to obtain four-dimensional (4D) images, the effective dose is increased in proportion to the scan time. Our purposes in this work were to measure the dose for the 256-slice CT, to compare it to that of the 16-slice CT-scanner, and to make a preliminary assessment of dose for dynamic 3D imaging (volumetric cine imaging). Our group reported previously that the phantom length and integration range for dosimetry needed to be at least 300 mm to represent more than 90 % of the line integral dose with the beam width between 20 mm and 138 mm. In order to obtain good estimates of the dose, we measured its line integral dose over a 300 mm range in PMMA (polymethylmethacrylate) phantoms of 160 mm or 320 mm diameter and 300 mm length. Doses for both CTs were compared for clinical protocol. The results showed that the 256-slice CT has smaller dose than the 16-slice CT in all examinations. The reason is the following: x-ray photons irradiated to the marginal portion near the slice collimator edge did not contribute to image formation, but they increased dose; the relative contribution of this portion was smaller for 256-slice CT than for 16-slice CT. Besides the 256-slice CT could take a large volume data in a one-rotation scan with sufficient image quality. For volumetric cine imaging, we found an acceptable scan time would be 6-11 s depending on examinations if dose must be limited to the same values as routine examinations with a conventional multi-detector CT. Finally, we discussed the studies necessary to make full usage of volumetric cine imaging.

The electric quadrupole coupling constants eqQ/h of 8B (I π = 2+, T 1/2 = 769 ms) and 13B (I π = 3/2−, T 1/2 = 17.4 ms) in single crystal TiO2 have been precisely measured by the β-NQR technique. The ratios of these Q moments to Q(12B) were determined as |Q(8B)/Q(12B)| = 4.882(32) and |Q(13B)/Q(12B)| = 2.768(24).

The momentum dependences of the nuclear spin polarization P and alignment A of 13B(I π = 3/2+, T 1/2 = 17.36 ms) produced in the 100A MeV 15N + Be collisions have been measured by detecting β-ray asymmetry. Because both the P and A were significantly smaller than the prediction from a simple kinematical model, some relaxation mechanisms must be take into account. Comparing the signs of the observed alignment of 12B, the sign of the quadrupole coupling constant eqQ of 13B in TiO2 was determined to be positive.

The pure nuclear spin alignments of 8Li and 8B were produced from the nuclear spin polarization applying the β-NMR method. The alignment correlation terms in the β-ray angular distribution were observed to test the G parity conservation in the nuclear β decay.

The g-factor of the exteremely proton-rich nucleus 23Al(T 1/2 = 0.47 s) has been measured for the first time, applying β-NMR technique on this nucleus implanted in Si. The obtained |g| = (1.58 ± 0.2) suggests that the spin of the ground state of 23Al is 5 / 2. The magnetic moment is determined as |μ| = (3.95 ± 0.55) μ N.

Hyperfine interactions of Na isotopes in single crystals have been studied using highly nuclear polarized 20,21,26,27,28Na beams provided by ISAC/TRIUMF. The degree of polarization kept in the crystals, the spin-lattice relaxation times, the electric quadrupole coupling constants and the initial distribution of the populations were measured. Such knowledge is indispensable for the application of the hyperfine interactions in the study of precision measurements such as the nuclear structure through nuclear moments and the fundamental symmetries.

The electric quadrupole coupling constants eqQ/h of 20Na (Iπ = 2+, T 1/2 = 449.7 ms), 21Na (Iπ = 3/2, T 1/2 = 22.49 s) and 25Na (Iπ = 5/2, T 1/2 = 59.6 s) in single crystal ZnO and TiO2 were precisely measured by applying the β-NMR technique. The ratio of the quadrupole moments between 20Na (25Na) and 21Na was determined to be 0.728 ± 0.023 (0.011 ± 0.002).

We report results of 77 Se NMR study for a newly found field-induced superconductor, κ-(BETS) 2 FeBr 4 . The nuclear spin lattice relaxation rate (1/T 1 ) above 25 K has a linear relation with temperature, 1/ T 1 = a T +b, which can be analyzed in a framework of normal metal with dipolar fields from uncorrelated 3 d local moments to the Se nuclei. However, 1/T 1 has an evident kink at 25 K and shows a remarkable decrease within a narrow temperature range of 2.5 K. Below 22.5 K, we found that 1/ T 1 follows a power law 1/ T 1 ∼ T 1.43 , although the material is still conductive. The temperature where 1/ T 1 shows a kink agrees with the temperature where the temperature devivative of the resistivity dρ/d T diverses. We discuss a possible reconstruction of the electronic state, which may attain magnetic correlation below this temperature.

The magnetic anisotropy and properties of Permalloy (Ni80Fe20) nanowire arrays fabricated by glancing angle deposition with substrate rotation were studied. Epitaxial Cu nanowires, with the long axis textured along the Cu[111] crystallographic direction, were used as a seed layer to grow the Ni80Fe20 nanowires. The nanowires exhibit a strong Ni80Fe20[311] texture as shown by x-ray diffraction, with a Ni80Fe20[111] diffraction peak uniformly distributed about the wire’s long axis normal to the substrate. Hysteresis loops taken at different angular orientations show that the magnetization saturates first along the wire’s growth direction normal to the substrate. Samples with an aspect ratio of approximately one have equal in- and out-of-plane coercivity. At low aspect ratios (∼0.5–1.5), the angular dependence of the remanence shows that the maximum remanence lies on the surface of a cone with its axis along the substrate normal. A model which contains biaxial anisotropy with a symmetry axis normal to the su...

The relationship between low oxygen injury and ethanol metabolism in twenty kinds of fruits and vegetables were investigated. The fruits and vegetables were stored under a continuous flow of 0%, 1%, 3%, 5% and 10% O 2 (balance N 2 ) or air at 20°C for 7 days. At 0% O 2 , low-oxygen injury was induced and developed during storage in all the commodities. A visible low-oxygen injury, skin pitting, appeared in okra, eggplant and cucumber fruit, while discoloration occurred in Chinese chive leaves, cauliflower, spinach leaves, eggplant and pear fruit. In addition, water-soaked tissue appeared in Chinese chive leaves, cauliflower, spinach leaves, strawberry, banana and pear fruit. Significantly, off-flavor or off-odor was detected in all commodities after storing in various duration during experiments. Hence, the occurrence of off-flavor or off-odor is the most common and important detrimental symptom that limit tolerance of fruits and vegetables to low oxygen. Since the levels of ethanol were higher than those of acetaldehyde in all commodities at day 7, the development of off-flavor or off-odor was related to increases in ethanol concentration but not to acetaldehyde during storage. The rate of increase in alcohol dehydrogenase (ADH) activity was lower than that in ethanol levels of fruits and vegetables, and changes in ADH activity did not necessarily correlate with the changes in the levels of ethanol or with the development of off-flavor or off-odor. However, the intensity of off-flavor or off-odor was associated with the levels of soluble solids content (SSC) of fruits and vegetables. Hence, SSC is important in determining the ethanol level that causes off-flavor or off-odor and has significant implications regarding the development of off-flavor or off-odor in fruits and vegetables.

The racial and gendered politics of the 1996 welfare reform movement incorporated an anti-immigrant stance that fundamentally altered non-citizens' access to public benefits. This article focuses on community mobilization efforts to reframe the discourse of the “immigrant welfare problem” in order to restore benefits in the aftermath of the Personal Responsibility Work Opportunity Reconciliation Act of 1996. Drawing from two years of participatory research in community organizations, I found immigrant rights groups engaged in a variety of counter-rhetorical strategies. These strategies invoked a rhetoric of moral reasoning in order to promote the en-titlement of non-citizens to remain eligible for public benefits. Utilizing social movement framing perspectives, I examine the claims-making strategies that appeal to common beliefs about aging, frailty, disability, and the obligation of the United States to its veterans. However, collective action frames comprised moral constructions of human rights for only specific immigrant groups that lost specific benefits. I consider the broader implications of such findings for immigrant and welfare rights movements. This case illustrates the significance of, and the dilemmas confronting, counter-framing strategies within community mobilization efforts.

The alignment correlation terms in the β -ray angular distributions from spin aligned 8 Li and 8 B have been measured precisely. The difference of these terms between the mirror pair is compared with the prediction. As a result, the G -parity violating induced tensor term is found to be small. The significant contribution from the second-forbidden matrix elements is shown by comparing with the β - α correlation coefficients.

The nuclear moments of 13B(Iπ = 3/2−, T1/2 = 17.36ms) have been re-measured precisely in order to establish the spin manipulation technique for the study of the alignment correlation term in mass system A = 13. From the β-NMR on 13B in Pt, the magnetic moment was determined as |μ(13B)| = 3.1778(5)μN. From the β-NQR on 13B in TiO2, the Q moment has been determined as |Q(13B)| = 36.6(8)mb. We have measured the alignment correlation term α_E for 13B β decay for the first time and obtained a preliminary result as α−(13B) = 0.15(12)%/MeV.

The momentum dependences of the nuclear spin polarization P and alignment A of 12 B ( I π = 1 + , T 1 / 2 = 20.20 ms) [ 13 B ( I π = 3 / 2 − , T 1 / 2 = 17.36 ms)] produced in 100 A MeV 13 C [ 15 N] + Be collisions have been measured by detecting the β -ray asymmetry. Because both the P and A were significantly smaller than the prediction from a simple kinematical model, some depolarization mechanisms must be taken into account related with the collision process itself. Comparing the signs of the observed alignment of 12 B and 13 B, the sign of the quadrupole moment Q ( 13 B) was determined to be positive.

The Knight shifts K and the spin-lattice relaxation time T 1 for the short-lived s-emitters 12B and 12N implanted into Pd have been measured by means of the s-NMR method. The results show that K depends on temperature. The obtained values of experimental K were compared with theoretical values derived with the KKR method.

The molecular organization of monolayers at the air–water interface of an amphiphilic azo-phane with unbranched n-dodecyl substituents differs from that of the analog with bulky ‘tert’-octyl substituents as seen in the area per molecule. Complexation with sodium ions from the aqueous subphase, as deduced from measurement of the surface potential, is facilitated by closer approach of the macrocycles for the n-dodecyl-substituted azo-phane, since two macrocycles form the complex with Na+. The compensation of the positive charge after complexation in the case of a two-component monolayer of the n-dodecyl-substitued azo-phane and octadecanoic acid, molar ratio azo-phane to acid = 2:1, enhances even more the complexation. The complex equilibrium constants and the contributions of the hydrophilic head group region to the surface potential are evaluated from Langmuir isotherm fits to the dependencies of the surface potential on the NaCl concentration in the aqueous subphase for the three monolayer systems investigated, i.e., the two different pure azo-phane monolayers and the two-component monolayer.

The magnetization behavior of antiferromagnetically coupled ferromagnetic bilayers with a uniaxial anisotropy is investigated analytically, with the aid of numeric calculation. Field trajectories giving a constant angle to the magnetization of one of the two layers, leaving the other as a variable in the in-plane field two-dimensional co-ordinate, and their envelopes are used to understand the magnetization behavior, including switching. These tools provide a good means of optimizing magnetic parameters to maximize the operating field margins of the recently proposed toggle-mode MRAM devices, including the thermal relaxation. Control of the especially low exchange coupling required for performance optimization is identified as a key technical issue, as well as increase of the operating field strength.