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This study investigated the non-equilibrium hydrogen absorption reaction paths of the AB 5 -type LaNi 2 Co 3 alloy using time-resolved in situ synchrotron X-ray diffraction. Diffraction data were collected every second for reactions under two hydrogen loading pressures. Hydrogen absorption with a hydrogen loading of 1 MPa rapidly transformed α phase to a transient phase (estimated to be LaNi 2 Co 3 H 3.1–3.6 , named γ∗); this has not previously been observed under equilibrium processes. The γ∗ phase continuously transformed into the γ phase (LaNi 2 Co 3 H 4.5–5.0), and the β phase (LaNi 2 Co 3 H ~3.6) was not formed. When 0.18 MPa of hydrogen was loaded, initially, the γ∗ phase appeared, followed by the formation of the β phase, finally transforming into the γ phase. These results indicate that a higher loading pressure promotes the formation of the γ∗ phase and assists its continuous transformation into the γ phase by enhancing the dissolution of hydrogen into the α and γ∗ phases. Image 1 • Hydrogen absorption processes were observed every second in real time. • Reaction paths via a new transient phase were found. • Fast and slow reactions followed different reaction paths. • The lattice expansion was discussed in relation to the hydrogen distribution. [ABSTRACT FROM AUTHOR]

We studied crystal structure and local structure of Mg2_xPrxNi4 (x = 0.6 and 1.0) and their deuterides using in situ neutron total scattering and first-principles calculations. The total scattering data were analyzed using Rietveld refinement and pair distribution function analysis (PDF). The crystal structure of Mg2-xPrxNi4 before deuterium absorption was C15b in space group F43m. No difference between the crystal and local (PDF) structures was observed. The crystal structure of Mg1.0Pr1.0Ni4D˜4 was found to be orthorhombic in space group Pmn2, with three deuterium occupation sites: PrNi3 and two types of bipyramidal Pr2MgNi2 that have a plane of symmetry composed of MgNi2. There is no significant difference between the crystal structure and the local structure of Mg1.0Pr1.0Ni4D˜4, On the other hand, the average crystal structure of the Mg-rich Mg1.4Pr0.6Ni4D˜3.6 was C15b with two deuterium occupation sites: PrNi3 and MgPrNi2 suggesting that the deuterium occupation shifts away from the Pr2MgNi2 bipyramid. First-principles relaxed structures also showed the shift of the hydrogen occupation site toward the Pr atom of the bipyramid, when induced by Mg substitution for the opposing Pr, resulting in hydrogen occupation in the MgPrNi2 tetrahedral site. The PDF partem of Mg1.4Pr0.6Ni4D˜3.6 cannot be refined below 7.2 Å in atomic distances using the C15b structure which was obtained from Rietveld refinement but can be done using an orthorhombic structure. It suggests that Mg1.4Pr0.6Ni4D˜3.6 was locally distorted to the orthorhombic. [ABSTRACT FROM AUTHOR]

The crystal structure and hydrogen storage properties of the alloys La0.67Mg0.33Ni2.5Co0.5, La0.7Mg0.3Ni2.8Co0.5 and La0.75Mg0.25Ni3.0Co0.5 were investigated. X-ray diffraction results suggested that all the three samples were mainly composed of PuNi3-type, Ce2Ni7-type and Pr5Co19-type phase. These alloys reversibly absorbed and desorbed hydrogen up to ∼1.0H/M under a hydrogen pressure of 2.5MPa at 333K. Moreover, the hexagonal structure of Ce2Ni7-type and Pr5Co19-type was retained during the absorption–desorption process. After hydrogenation, a volumetric expansion of 22.7% was observed for Ce2Ni7-type phase, and an expansion of 1.3% still remained after dehydrogenation. [Copyright &y& Elsevier]

Positron lifetime spectroscopy was applied to examine the synergistic effect of hydrogen and plastic straining on the vacancy generation in iron. Hydrogen enhanced the increase in mean positron lifetime, τ m, by plastic straining and elevated the recovery temperature of τ m on isochronal annealing. Multi-component analyses of positron lifetime spectra showed that the presence of hydrogen enhances the generation of vacancies, rather than of dislocations. These results are consistent with previous interpretations on thermal desorption analysis of hydrogen in deformed steels. [Copyright &y& Elsevier]

Positron lifetime spectroscopy is a powerful tool for the study of vacancy-type defects in solids. Our positron lifetime measurements have revealed that huge numbers of excess vacancies are formed in addition to dislocations during the first hydrogen absorption process of LaNi5 and excess vacancies becomes mobile and form microvoids by a thermal activation process. For further investigation, theoretical approaches using electronic structure calculations are indispensable. In this work, we have performed theoretical calculations of positron lifetime for LaNi5–H system using first principles electronic structure calculations. By comparison between the theoretical and experimental positron lifetimes, one of the defect components during hydrogen absorption can be ascribed to the annihilation at vacancy-clusters composed of two or three Ni vacancies. The positron lifetime of the vacancy-cluster component increases over 400 ps during isochronal annealing after hydrogen desorption. The vacancy-cluster may contain not only Ni vacancies but also La vacancies, since the vacancy-cluster composed of only Ni vacancies cannot yield such a long positron lifetime. [Copyright &y& Elsevier]

Abstract: The effect of the hydrogen absorption and desorption process on the production of lattice defects in pure Pd was studied by means of positron lifetime spectroscopy. Pd hydrogenated and dehydrogenated at 623K contains some dislocations but few metal vacancies. In contrast, a remarkable vacancy production was observed in Pd hydrogenated at 623K and subsequently electrochemically dehydrogenated at ambient temperature. This result shows that vacancies are formed during the hydrogen desorption process at RT, and suggests that the vacancy formation is caused by the effect of stresses accompanied by the phase separation. [Copyright &y& Elsevier]

Examines the evanescent-light guiding of atoms through hollow optical fiber for optically controlled atomic deposition. Spatial distribution of the guided atom flux; Details on the control of the deposition rate; Enhancement of the guided atom flux ratio.

Capacitance-voltage (C-V) characteristics of a Si/C&sub60; heterojunction, i.e., a HF solution (7.3% HF+30% NH[sub 4]F) treated Si surface interfaced solid crystal of C&sub60; molecules, were measured while applying various ac frequencies. The entire C[sub 60] thin film and near-interface region of the Si wafer behaved as a depletion region, with the C – V curve showing two distinct regions: one above and one below a threshold bias voltage. Below the threshold, C –V characteristics were dependent on applied frequency, which suggests the presence of interface states that only affect capacitance at lower frequencies. This frequency dependence was analyzed by assuming a suitable equivalent circuit, and based on derived curve-fitting circuit parameters the interface states density was accordingly estimated to have a value as low as ∼ 10[sup 11]/cm² eV. Such a small density indicates that only a few lattice defects occur within the interface of the HF-treated Si surface and C&sub60; crystal. Although no frequency dependence was observed above the threshold, the C – V characteristics were found to be dependent on the width of the depletion region in Si. [ABSTRACT FROM AUTHOR]

STUDY DESIGN.: A retrospective analysis of prospectively collected data from consecutive patients undergoing transcranial electrical motor-evoked potential (TCE-MEP: compound muscle action potentials) monitoring during cervical spine surgery. OBJECTIVE.: To divide the warning threshold of TCE-MEP amplitude changes on the basis of origin into the spinal tract and spinal segments and decide warning thresholds for each. SUMMARY OF BACKGROUND DATA.: The parameter commonly used for the warning threshold in TCE-MEP monitoring is wave amplitude, but amplitude changes have not been examined by anatomical origin. METHODS.: Intraoperative TCE-MEP amplitude changes were reviewed for 357 patients with cervical myelopathy. Most of the patients were monitored by transcranial electrical stimulated spinal-evoked potential combined with TCE-MEP. The warning threshold of TCE-MEP was taken as waveform disappearance. For each patient, amplitude changes were separated, according to origin, into the spinal tract and spinal segments and compared with clinical outcome. RESULTS.: Assessable TCE-MEP waves were obtained in 350 cases. Disappearance of TCE-MEP waves, which were innervated by the spinal levels exposed to the surgical invasion, was seen in 11 cases. Disappearance of TCE-MEPs, which were innervated by the spinal levels inferior to them, was seen in 43 cases. There was no postoperative motor deficit in those cases. However, such deficits caused by spinal segment injury were seen in 2 cases, which showed that intraoperative amplitude decreased to 4.5% and 27%. CONCLUSION.: If we had established the warning threshold as 30% of the control amplitude, we would likely have prevented both cases of postoperative motor deficits, but 106 (30.3%) cases would have become positive cases. If we had established the warning threshold separately as wave disappearance for the spinal tract and 30% of the control amplitude for the spinal segments, sensitivity and specificity would have been 100% and 83.7%, respectively. Dividing the warning threshold on the basis of origin of amplitude changes could reduce false-positive cases and prevent intraoperative injuries. [ABSTRACT FROM AUTHOR]

Metal-hydride compressors are considered as an alternative to mechanical compressors in Hydrogen Refueling Stations. In this paper, several Ti-based AB 2 compounds were synthesized and their hydrogen sorption properties were evaluated under ultra-high pressure up to 40 MPa. All the studied compounds exhibit absorption plateau pressure close to or higher than 10 MPa at 30 °C. The substitution by a small amount of Al was shown to drastically decrease the hysteresis. All the compounds herein studied follow the trend ln (P) ∝ − V 0 , except for the Nb-containing compound. This compound has a different behavior towards hydrogenation and exhibits sorption pressure much higher than expected from the above-mentioned relationship. It was confirmed that the Al and Nb substitution in AB 2 compounds plays a great role on reducing hysteresis and increasing the sorption pressure, respectively. • Hydrogenation properties of AB 2 compounds were evaluated at pressures up to 40 MPa. • Al substitution into AB 2 compounds plays a significant role in reducing hysteresis. • Nb-containing compound exhibits higher plateau pressures. • Heating the improved compound by 50 °C allows pressurization from 24.2 to 41.8 MPa. [ABSTRACT FROM AUTHOR]

Abstract: The hydrogen absorption behavior of Mg fiber was observed over a temperature and pressure range of 560–620 K and 0.4–1.6 MPa, respectively. The Mg fiber had a diameter of 200 nm to 1 μm and consisted of grains smaller than 100 nm. The absorption kinetics was analyzed using the Arrhenius and Johnson-Mehl-Avrami-Kolmogorov equations. Obtained kinetics parameters for the Mg fiber were compared with those of conventional Mg powder with the particle size of tens of micrometers. The initial reaction rate of the Mg fiber was larger than that of Mg powder. The absorption behavior was well-described by the nucleation and growth model. The values of Avrami exponent for the initial absorption varied from 0.8 to 2.5; these values are larger than those obtained for Mg powder (0.6–1.3). The Avrami exponents varied wider at higher temperatures, and increased with decrease in pressure. The obtained values of Avrami exponent for both the Mg fiber and the powder corresponded to a reaction through the rate-limiting step of hydrogen diffusion in Mg. The activation energies were estimated to be 69 kJmol−1–H2 for the powder Mg and 72 kJmol−1–H2 for the Mg fiber, respectively. The pre-exponential factor in the Arrhenius equation for the Mg fiber was approximately three times larger than that for the Mg powder. [Copyright &y& Elsevier]

Abstract: The hydrogenation properties of Ti1.0V1.1Mn0.9 alloys with a BCC structure, prepared using two V materials with different oxygen concentrations, were studied. The sample prepared using a conventional-grade V material contained 0.530mass% of oxygen, and the other sample prepared from a low-oxygen V material contained 0.051mass% of oxygen. Both samples showed P–C isotherms with two plateaus corresponding to formation of monohydrides and dihydrides. The sample with the higher oxygen concentration had an equilibrium pressure for dihydride formation 6.7 times higher than that of the sample with the lower oxygen concentration at 0°C. There was no significant difference between the two samples with regard to the equilibrium pressure for formation of monohydride or the hydrogen capacity. The formation enthalpies were calculated from the van’t Hoff plots: −30.2kJ/molH2 and −35.5kJ/molH2 for the dihydrides, and −39.7kJ/molH2 and −39.8kJ/molH2 for the monohydrides. Scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM–EDX) and X-ray diffraction (XRD) indicated that the sample with the higher oxygen concentration contained a Ti-rich secondary phase, which caused changes in the composition and in the lattice parameter of the main phase. These results indicated that increasing the oxygen concentration altered the hydrogenation properties as a result of (1) the effect of oxygen solved in the main phase on hydrogen occupation and (2) a composition change resulting from secondary phase formation. [ABSTRACT FROM AUTHOR]

Abstract: The hydrogenation behaviour of the Gd0.5Y0.5Ni3.75Al0.25Mg compound was studied by in situ X-ray diffraction under hydrogen pressure and at room temperature. The presence of gadolinium induce an exchange between the 4a (occupied by RE) and 4c sites (occupied by Mg). Nevertheless, only the Gd atoms are mixed by Mg atoms and no occurrence of Y/Mg mixing can be observed. The exchange is then directly correlated with the 4f electrons. Moreover, in the compounds without Gd (i.e. YNi3.75Al0.25Mg) no exchange was observed. The structure of the metal hydrides was carefully investigated by refining the in situ XRD patterns obtained under various H2 pressures. It was concluded that the structure remains cubic during the sorption process with an increase of the cell volume close to 13%, in agreement with the maximum sorption capacity (i.e. 3H/formula unit). No variation of the exchange rate between the hydride and the initial intermetallic can be highlighted. The changes of both the crystallite size and lattice strains during the sorption process (i.e. along the PC isotherms) indicated that a decrease of the crystallinity is observed but no HIA process occurred. [Copyright &y& Elsevier]

Positron lifetime spectroscopy is a sensitive tool for the study of vacancy-type defects in solids. Our positron lifetime measurements have revealed that huge numbers of excess vacancies are formed in addition to dislocations during the first hydrogen absorption process in some hydrogen storage materials. In this work, we have performed first-principles calculations of positron lifetimes of vacancies as well as the bulk state in LaNi5–H and Pd–H systems in order to identify lattice defects formed during hydrogen absorption and during isochronal annealing after hydrogen desorption. By comparison between the experimental and theoretical positron lifetimes, one of the defect components formed during hydrogen absorption can be ascribed to the annihilation at the vacancy clusters composed of two or three vacancies in both LaNi5–H and Pd–H systems. During isochronal annealing after hydrogen desorption in LaNi5, the positron lifetime of the vacancy-cluster component in LaNi5 increases from 190 to over 400 ps, which indicates the formation of three-dimensional vacancy clusters. On the other hand, the vacancy-cluster component in Pd decreases from 200 to 160 ps during isochronal annealing. This suggests that not three-dimensional but two-dimensional vacancy clusters are formed in the recovery process of vacancies in Pd. [Copyright &y& Elsevier]

Ti 1+ y Cr 2- x Mn x compounds with a hexagonal MgZn 2 -type structure were investigated for their potential use in metal-hydride (MH) compressor applications. Here, the targeted MH compressor should absorb hydrogen below 30 MPa at 30 °C and desorb hydrogen at 80 MPa when heated at 80 °C. The pressure (P)-composition (C) isotherms were measured at pressures up to 40 MPa. Because of the very high pressures, the fugacity was taken into account. Details are given on how to determine the absorption and desorption enthalpies and entropies from the fugacity. The Van't Hoff plots were used to estimate the critical temperatures (T C). The P – C isotherms of all the compounds exhibit relatively small hysteresis and flat plateaus but the absorption and desorption pressures need to be increased. Superstoichiometry of y = 0.05 tends to decrease the plateau pressure and increase its slope, which is not desired for our target. On the other hand, the increase of Mn content led to higher T C as well as higher and flatter plateaus. Cr is a key element to get small hysteresis. • Detailed method for determination of the Van't Hoff plots considering the fugacity. • Critical temperatures evaluated by extrapolation of Van't Hoff plots. • Higher Mn content increases the critical temperature. • Strong effect of Cr for decreasing the hysteresis. [ABSTRACT FROM AUTHOR]

In the present work are reported the hydrogen generation performances of Long Period Stacking Ordered (LPSO) compounds with 18R, 14H and 10H-type structures by hydrolysis reaction in simulated seawater solution (35 g/L NaCl). LPSO compounds and LPSO + Mg alloys synthesized by induction melting are described in the light of their microstructural and electrochemical properties. Except for 10H type, all LPSO present improved H 2 generation features compared to pure Mg. Indeed, 80% of the reaction is achieved in less than 40 minutes. The highest generation yield of 90% is obtained for single phase LPSO Mg 87.6 Ni 5.5 Y 6.9. Alloys containing both Mg and LPSO beneficiate from galvanic coupling between the two phases leading to higher reactivity. The activation energies of 27.3 and 85.4 kJ/mol determined for Mg 91 Ni 4 Y 5 (14H + Mg) and Mg 83.3 Cu 7.2 Y 9.5 (18R) respectively clearly highlight this benefit from galvanic coupling. • LPSO produces H 2 by hydrolysis in 0.6 M NaCl solution. • Galvanic coupling occurs between LPSO and Mg. • Metallic clusters in LPSO are responsible of the hydrolysis performances. [ABSTRACT FROM AUTHOR]

For high pressure metal hydride (MH) compressor applications, it is important to have a thorough understanding of the hydrogenation properties of MH forming compounds under high pressure and temperature conditions, which are still little studied. Here, a Ti 0.90 V 0.30 Mn 1.00 Ni 0.80 compound with MgZn 2 -type AB 2 structure has been investigated by Sieverts' method over a wide pressure and temperature range (up to 100 MPa and between −80 and 120 °C). This provided clear experimental evidence of the downward curvature of the van't Hoff plot in the high-pressure region, which arises from the non-ideal behavior of hydrogen. In this paper, we also show that the high-sorption pressures can be well estimated by the van't Hoff equation using low-pressure data. Ultimately, this study was combined with synchrotron radiation X-ray diffraction (SR-XRD) performed in an effort to monitor the structural evolution of the compound in situ under ultra-high hydrogen pressure. We found that even under extreme conditions of 2 GPa and 200 °C, both the main AB 2 phase and the secondary CsCl-type AB phase were fully hydrogenated and their structures were conserved. The existence of a critical temperature for the AB 2 -H 2 system was demonstrated from the evolution of the SR-XRD patterns recorded for several temperatures during the desorption process. [Display omitted] • Pressure-composition isotherms were measured up to 100 MPa using Sieverts' method. • High sorption pressures can be estimated from low pressure data using fugacity. • Curvature of the van't Hoff plot was observed experimentally at high pressures. • Hydrogen desorption isotherms were plotted from in situ synchrotron data. • Critical temperature features were observed in continuous unloading experiments. [ABSTRACT FROM AUTHOR]

In order to develop suitable hydrogen storage materials for thermochemical hydrogen compressor using metal hydride, it is necessary to evaluate hydrogen storage properties in high pressure range up to 100 MPa. However, several unexpected issues arose for measuring P-C isotherms up to 100 MPa, which was not observed for the relatively lower pressure range. This led to strange shape of P-C isotherms. In order to solve these, in this paper, we considered the effect of the inner volume of the valve, the pressure increment by a valve operation, and the volume expansion of the sample upon hydrogen absorption. Taken into account these factors, reasonable P-C isotherms were successfully obtained. [Display omitted] • Pressure-composition isotherms were successfully drawn for pressures up to 100 MPa. • Valve volume needs to be considered otherwise the capacity is overestimated. • Valve closure causes a pressure increase that also affects the capacity calculation. • Sample expansion during hydrogenation affects hydrogen content calculations. [ABSTRACT FROM AUTHOR]

Hydrolysis of Magnesium with water is an excellent way to produce H 2 at high rate, especially when alloyed with nobler elements that accelerate its corrosion. In this work, the hydrogen generation properties of four Magnesium based alloys with Long Period Stacking Ordered (14 H-LPSO) structures (Mg 91 Cu 4 Y 5 ; Mg 91 Ni 4 Y 5 ; Mg 91 Ni 4 Gd 5 and Mg 91 Ni 4 Sm 5) are studied through standard electrochemical methods. The hydrolysis experiment on coarse powder are coherent with the electrochemical measurements performed on polished surface. The rare earth (Y, Gd or Sm) and transition metal (Ni or Cu) involved in the LPSO are found to have a significant influence on the corrosion and hydrolysis properties of alloys with 14 H-LPSO structures. • Alloys with high content of 14 H-LPSO phase present very good hydrolysis performances. • Rare earth nature (Y, Gd, Sm) influences hydrolysis and electrochemical properties via modifying alloy microstructure. • Electrochemical measurements on bulk surface corroborate hydrolysis experiments with powder. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective single-center study. Objective: To investigate how functional recovery is influenced by anterior compression of the spinal cord (ACS) and instability at the level of ACS after laminoplasty in patients with cervical spondylotic myelopathy. Summary Of Background Data: There have been many reports that patients whose spinal cord cannot be decompressed sufficiently after laminoplasty are likely to show unsatisfactory neurologic outcomes. Notably, postoperative ACS is well known to cause problems. Clinically, however, it remains unknown how functional recovery is inhibited by postoperative ACS. Methods: Sixty-four consecutive patients who underwent expansive laminoplasty for the treatment of myelopathy at our hospital between 1998 and 2005 were reviewed. All 64 patients were available for follow-up. The average follow-up period was 97 months (60-156 months). Patients were divided into 2 groups: the ACS(+) group comprised 16 patients who had ACS 3 years postoperatively, and the ACS(-) group comprised 48 patients with no ACS. Clinical outcome was compared in terms of the Japanese Orthopaedic Association score (mean total score, mean score of each item, and recovery rates). Results: Demographics were similar between the 2 groups. Mean Japanese Orthopaedic Association score at final follow-up was 12.1 points (recovery rate 34.0%) in the ACS(+) group and 13.8 points (recovery rate 56.6%) in the ACS(-) group, and there was a significant difference in recovery rate between the groups (P < 0.05). Notably, a significant difference was found between the 2 groups in improvement of upper extremity motor function (P < 0.05). In addition, we found that not only the presence of ACS but also postoperative hypermobility of the intervertebral segment with ACS influenced clinical outcome negatively. Conclusion: These results demonstrate that ACS after laminoplasty could be a risk factor for clinical outcome and might prevent improvement in upper extremity motor function in patients with myelopathy. [ABSTRACT FROM AUTHOR]

Abstract: The hydrogenation and dehydrogenation behaviours of the YNi3.5Al0.5Mg compound were studied by in situ X-ray diffraction under hydrogen pressure and at room temperature. The changes of (i) the lattice parameters, (ii) the crystallite size and (iii) the lattice strain during the sorption process (i.e. along the PC isotherms) were studied. These results indicate that the crystallite size decreases by a factor of 2. The micro deformations increase at first and then tend to almost zero at the end of the sorption cycle. This behaviour is explained in terms of co-existence of the metal (i.e. phase) and metal hydride (i.e. phase) phases. The change in crystallinity is consistent with the hydrogen induced amorphisation process existing in a lot of AB2 compounds. No anisotropic effects can be highlighted on this pseudo-AB2 compounds in contrary with what could be observed in AB5 compounds. [Copyright &y& Elsevier]

This study demonstrates the ability to fabricate lightweight, ductile but mechanically strong magnesium alloy (AZ91D) composites by introducing a small number of high crystalline multi-walled carbon nanotubes. It is demonstrated that 1% of relatively short and straight carbon nanotubes distributed homogeneously on the outer surface of magnesium powders act as an effective reinforcing filler to prevent deformation, thereby contributing to the enhanced tensile strength of magnesium alloy composites (e.g., from 315 to 388MPa). [Copyright &y& Elsevier]

We studied the possible application of high-TC superconducting traction transformer to railway rolling stock, and designed an iron core type two-leg 4 MVA superconducting traction transformer for Shinkansen. This traction transformer has a primary winding, four secondary windings and a tertiary winding. The four secondary windings are independent of each other. Two secondary windings are arranged around each leg of the iron core and placed inside and outside the primary and tertiary windings. In this study, we fabricated a high-TC super-conducting coil whose form and dimension are the same as those of the inner secondary winding. This coil can be used as the inner secondary winding of the experimental high TC superconducting traction transformer that will be fabricated in the future. The inner secondary winding has 96 turns and a later with eight parallel Bi2223 superconducting tapes. Transposition among the superconducting tapes is performed 15 times every six turns. We measured the voltage-current and AC loss characteristics when it was cooled in saturated and sub-cooled liquid nitrogen. [ABSTRACT FROM AUTHOR]

A 60-kA high-temperature-superconductor (HTS) current lead has been fabricated and tested aiming at the application to a fusion magnet system. The HTS current lead consists of a forced flow cooled copper part and a conduction cooled HTS part. The HTS part is composed of 288 Ag-alloy sheathed Bi-2223 tapes, which are cylindrically arrayed on a stainless steel tube. For the Ag alloy, Ag–10at.%Au is used to obtain low thermal conductivity. Operation of a 60-kA current, which is the world record, was successfully achieved at a cooling condition of 20 K, 3.2 g/s for the copper part, and a low heat leak of 4.8 W at 4.2 K was demonstrated. This result indicates that the electric power of a refrigerator to cool the current lead can be reduced by 1/3 of that in a conventional current lead. In conclusion, technology of a large HTS current lead for fusion application is established. [Copyright &y& Elsevier]

We fabricated two high-T[sub c] superconducting coils that simulated the winding of a traction transformer for railway rolling stock. The multi-layer solenoid coil to simulate the primary winding of the transformer had five layers with a single Bi2223 superconducting tape. The closed solenoid coil to simulate the secondary winding of the transformer had one layer with eight parallel Bi2223 superconducting tapes. We measured the voltage-current, AC loss and current sharing characteristics of these coils cooled in saturated liquid nitrogen at 77 K. As a result, we concluded that the multi-layer solenoid coil is applicable to the primary winding and the closed solenoid coil is also applicable to the secondary winding. [ABSTRACT FROM AUTHOR]

STUDY DESIGN.: A prospective, comparative study. OBJECTIVE.: We developed a hybrid graft (HBG) of porous [beta]-tricalcium phosphate ceramics/percutaneously harvested bone sticks/autologous bone marrow aspirate for lumbar posterolateral fusion (PLF). The aim of this study was to investigate the efficacy of the HBG as a substitute for conventional corticocancellous iliac autografts. SUMMARY OF BACKGROUND DATA.: Iliac crest bone graft (ICBG) has been traditionally used as the golden standard for lumbar spinal fusion. The significant complication rate associated with harvesting corticocancellous ICBG, however, has encouraged development of alternative graft substitutes. METHODS.: From September 2005, 61 consecutive patients underwent decompressive laminotomy and 1-level instrumented PLF. Each patient in this study had the constructs of the HBG placed on 1 side of the intertransverse process gutter. An autologous local bone graft (LBG) harvested during decompressive laminotomy was placed on the other side as a control. Radiographic evaluation was performed at 6 months, 1 year after surgery, and subsequently on an annual basis. The fusion statuses on either side of vertebra were compared. RESULTS.: The flexion-extension motion in the dynamic x-rays at the target level decreased over time. Only 1 case exhibited over 5° of angular motion 2 years after surgery. In the evaluation of fusion status, the fusion rate for the HBG side (68.9% at 6 months, 83.6% at 1 year, 93.5% at 2 years) was higher than that for the LBG side (49.2% at 6 months, 75.4% at 1 year, 89.1% at 2 years) with a significant difference at 6 months after surgery. No significant complications at the donor site were found postoperatively. CONCLUSION.: The HBG promoted posterolateral spinal fusion without significant donor site morbidity. Because of its efficacy and safety, this hybrid construct seems promising as an alternative to conventional iliac bone grafts for lumbar spinal fusion. [ABSTRACT FROM AUTHOR]

STUDY DESIGN.: A case report of a patient with adhesive arachnoiditis after combined spinal and epidural anesthesia. OBJECTIVE.: To report an extremely rare case of paraplegia due to adhesive arachnoiditis with extensive syringomyelia (ES) and a giant anterior arachnoid spinal cyst (AASC) after spinal and epidural anesthesia for obstetric surgery. SUMMARY OF BACKGROUND DATA.: Progressive inflammation of the arachnoid mater due to trauma, infection, or hydrocortisone was reported as early as the 1970s. However, coexistence of ES and a giant AASC after spinal and epidural anesthesia is extremely rare. METHODS.: A 29-year-old woman suffered from sudden anuresis 5 months after spinal and epidural anesthesia for a cesarean section and subsequently experienced paraplegia and numbness below the chest. Magnetic resonance imaging showed an AASC compressing the spinal cord at T1-T6 and an adhesive lesion at T7. Posterior laminectomy at T6-T7 and adhesiolysis for arachnoid adhesion at T7 were performed. Although there was slight recovery of locomotive function postoperatively, it gradually worsened until 3 years after surgery. Magnetic resonance imaging at that time demonstrated a giant AASC and ES at the lower-thoracic cord. The cord compressed by the AASC became thinner sagittally. Secondary surgery involving posterior laminectomy at T5-T6 and insertion of a cyst-peritoneal shunt into the AASC was performed. RESULTS.: The patient could walk without a cane 3 years after the shunt operation, although numbness and motor weakness of the lower extremities remained. Magnetic resonance imaging 3 years after the shunt operation showed a reduction of the AASC and decompression of the cord despite no improvement in ES. CONCLUSION.: This is the first report of a patient with a giant AASC and ES caused by spinal and epidural anesthesia. Although the optimal surgical treatment for these conditions remains unclear, shunting of the cyst effectively prevented the progression of symptoms. [ABSTRACT FROM AUTHOR]