Search

Pulsating Aurora (PsA) is one of the major classes of diffuse aurora associated with precipitation of a few to a few tens of keV electrons from the magnetosphere. Recent studies suggested that, during PsA, more energetic (i.e., sub‐relativistic/relativistic) electrons precipitate into the ionosphere at the same time. Those electrons are considered to be scattered at the higher latitude part of the magnetosphere by whistler‐mode chorus waves propagating away from the magnetic equator. However, there have been no actual cases of simultaneous observations of precipitating electrons causing PsA (PsA electrons) and chorus waves propagating toward higher latitudes; thus, we still do not quite well understand under what conditions PsA electrons become harder and precipitate to lower altitudes. To address this question, we have investigated an extended interval of PsA on 12 January 2021, during which simultaneous observations with the Arase satellite, ground‐based all‐sky imagers and the European Incoherent SCATter (EISCAT) radar were conducted. We found that, when the PsA shape became patchy, the PsA electron energy increased and Arase detected intense chorus waves at magnetic latitudes above 20°, indicating the propagation of chorus waves up to higher latitudes along the field line. A direct comparison between the irregularities of the magnetospheric electron density and the emission intensity of PsA patches at the footprint of the satellite suggests that the PsA morphology and the energy of PsA electrons are determined by the presence of “magnetospheric density ducts,” which allow chorus waves to travel to higher latitudes and thereby precipitate more energetic electrons. Pulsating Aurora (PsA) is a kind of diffuse aurora associated with periodic precipitation of energetic electrons from the near‐Earth space into the atmosphere. Recent research has shown that, during PsA events, energetic particles at the sub‐relativistic energy range precipitate into the atmosphere. We speculate that such particles are scattered by wave‐particle resonance with natural electromagnetic waves, called chorus waves, at higher magnetic latitude regions. However, there has been no experimental case of PsA during which propagation of the chorus waves to higher magnetic latitudes was confirmed; thus, we still do not fully understand when and why PsA electrons become more energetic. Here, we investigate a PsA event on 12 January 2021, simultaneously observed by the Arase satellite, ground‐based all‐sky imagers and the European Incoherent SCATter (EISCAT) radar. We found that, when the PsA shape was patchy, the energy of precipitating electrons increased and chorus waves were observed at high latitudes in the magnetosphere. Comparing the magnetospheric electron density with the PsA brightness seen from the ground, we suggest that both the PsA shape and the energy of precipitating electrons were influenced by the so‐called magnetospheric ducts, which guide chorus waves to high‐latitudes regions where they interact with more energetic electrons. Examined simultaneous observations of Pulsating Aurora (PsA) with the Arase satellite, ground‐based all‐sky imagers, and the EISCAT radarFound a relationship among the patchy PsA, the enhanced energy of PsA electrons, and the chorus wave propagation to high‐latitudes (>20°)Arase observations suggest that the observed relationship can be explained by the ducted propagation of chorus waves Examined simultaneous observations of Pulsating Aurora (PsA) with the Arase satellite, ground‐based all‐sky imagers, and the EISCAT radar Found a relationship among the patchy PsA, the enhanced energy of PsA electrons, and the chorus wave propagation to high‐latitudes (>20°) Arase observations suggest that the observed relationship can be explained by the ducted propagation of chorus waves

Rheumatoid arthritis (RA) is known to cause secondary osteoporosis and fragility fractures. This study aimed to identify biomarkers predictive of bone mineral density (BMD) change at three anatomical sites in patients with RA. We conducted a prospective longitudinal study in patients with RA. In 2012, we recruited 379 patients from an RA cohort, 329 of whom underwent evaluation of blood and urine biomarkers together with measurement of BMD in the lumbar spine, proximal femur, and distal forearm. The BMD in these three regions was reassessed in 2014. We performed multivariate linear regression analysis to identify those factors associated with BMD change. The averages of age, body mass index, and disease activity score in 28 joints (DAS28) at baseline were 63.2 (minimum to maximum, 32–85), 21.3 (12.3–30.0), and 3.2 (0.1–5.9), respectively. Univariate analysis showed that the annual BMD change was significantly associated with the use of steroid, bisphosphonate (BP) or vitamin D (VitD), and serum homocysteine in the lumber spine; DAS28, the use of BP or VitD, CRP, and anti-cyclic citrullinated peptide antibody (ACPA) in the proximal femur; and the dosage of MTX, the use of BP or VitD, and serum tartrate-resistant acid phosphatase 5b (TRACP-5b) in the distal forearm, respectively. Predictive biomarkers for BMD change in RA patients differ at each anatomical site. Practitioners should treat each anatomical site with different markers and prescribe osteoporosis drugs to prevent fractures for RA patients.

Drastic variations of radiation‐belt/ring current electrons are the result of competing processes of acceleration, transport, and loss. For subrelativistic energetic electrons (10–100 keV), one of the promising loss mechanisms is precipitation into the atmosphere due to pitch angle scattering by whistler mode chorus waves. The efficiency of the scattering has yet to be quantified by direct observations, however. Using in situ measurements by the ERG (Arase) spacecraft in the midnight‐to‐dawn sector at and around the magnetic equator, we demonstrate that the full filling of energetic electron loss cones occurs commonly, associated with typical‐amplitude (greater than 50 pT) chorus waves. The spatial distribution of the loss cone filling indicates that the efficient scattering is limited to |MLAT|< 10°. Drastic variations of high‐energy (10–100 keV) electrons in the Earth's magnetosphere are the result of competing processes of acceleration, transport, and loss. In order to understand their dynamics, therefore, it is important to quantify each process. One of the promising loss mechanisms is precipitation into the atmosphere due to the interaction with electromagnetic waves called “chorus waves.” However, the precipitation rate has yet to be quantified by direct observations in the interaction region. Using in situ measurements by the ERG (Arase) spacecraft in the magnetosphere, we demonstrate that the full throttle precipitation occurs commonly, associated with typical‐amplitude (greater than 50 pT) chorus waves. The observed spatial distribution indicates that the efficient interaction is confined at/around the magnetic equator. Spatial distribution of medium‐energy loss cone electrons in the low‐latitude magnetosphere is shown for the first timeThe strong diffusion is common when chorus waves are activeStrong scattering occurs only at the near‐equatorial region (|magnetic latitude|< 10°) in the midnight‐to‐dawn sector

We present the first and direct comparison between magnetospheric plasma waves and polar mesosphere winter echoes (PMWE) simultaneously observed by the conjugate observation with Arase satellite and high‐power atmospheric radars in both hemispheres, namely, the Program of the Antarctic Syowa Mesosphere, Stratosphere, and Troposphere/Incoherent Scatter Radar at Syowa Station (SYO; −69.00°S, 39.58°E), Antarctica, and the Middle Atmosphere Alomar Radar System at Andøya (AND; 69.30°N, 16.04°E), Norway. The PMWE were observed during 03–07 UT on 21 March 2017, just after the arrival of corotating interaction region in front of high‐speed solar wind stream. An isolated substorm occurred at 04 UT during this interval. Electromagnetic ion cyclotron (EMIC) waves and whistler mode chorus waves were simultaneously observed near the magnetic equator and showed similar temporal variations to that of the PMWE. These results indicate that chorus waves as well as EMIC waves are drivers of precipitation of energetic electrons, including relativistic electrons, which make PMWE detectable at 55‐ to 80‐km altitude. Cosmic noise absorption measured with a 38.2‐MHz imaging riometer and low‐altitude echoes at 55–70 km measured with an medium‐frequency radar at SYO also support the relativistic electron precipitation. We suggest a possible scenario in which the various phenomena observed in near‐Earth space, such as magnetospheric plasma waves (EMIC waves and chorus waves), pulsating auroras, cosmic noise absorption, and PMWE, can be explained by the interaction between the high‐speed solar wind containing corotating interaction regions and the magnetosphere. EMIC waves and chorus waves in the magnetosphere and PMWE in the mesosphere were observed simultaneously by the conjugate observationPMWE were detected by the PANSY and MAARSY radars in both Northern and Southern Hemispheres during the equinox periodThe temporal variation of the chorus wave power was quite similar to those of PMWE powers observed in both hemispheres

AimsIn the 1990s, a bioactive bone cement (BABC) containing apatite-wollastonite glass-ceramic (AW-GC) powder and bisphenol-a-glycidyl methacrylate resin was developed at our hospital. In 1996, we used BABC to fix the acetabular component in primary total hip arthroplasty (THA) in 20 patients as part of a clinical trial. The purpose of this study was to investigate the long-term results of primary THA using BABC.Patients and MethodsA total of 20 patients (three men and 17 women) with a mean age of 57.4 years (40 to 71), a mean body weight of 52.3 kg (39 to 64), and a mean body mass index (BMI) of 23.0 kg/m2(19.8 to 28.6) were evaluated clinically and radiologically. Survival analyses were undertaken, and wear analyses were carried out using a computer-aided method.ResultsThe mean follow-up was 17.6 years (1.5 to 21.1). Radiological loosening occurred in four sockets with aseptic loosening at a mean of 7.8 years (1.5 to 20.7). Kaplan–Meier survival analyses using revision of the acetabular component, radiological loosening of the acetabular component, and the worst-case scenario with revision of the acetabular component to include the two patients lost to follow-up as endpoints yielded survival rates of 94.7%, 84.4%, and 85.0% at ten years, and 70.0%, 84.4%, and 62.8% at 20 years, respectively. Wear analysis revealed a mean linear wear rate of 0.068 mm per year.ConclusionThe long-term results of primary THAs using BABC were unsatisfactory. Its brittle nature and poor handling properties need to be improved before it becomes an alternative method of fixing the acetabular component in cemented THA.Cite this article: Bone Joint J2019;101-B:787–792.

Equatorial noise (EN) emissions are observed inside and outside the plasmapause. EN emissions are referred to as magnetosonic mode waves. Using data from Van Allen Probes and Arase, we found conversion from EN emissions to electromagnetic ion cyclotron (EMIC) waves in the plasmasphere and in the topside ionosphere. A low‐frequency part of EN emissions becomes EMIC waves through branch splitting of EN emissions, and the mode conversion from EN to EMIC waves occurs around the frequency of M/Q= 2 (deuteron and/or alpha particles) cyclotron frequency. These processes result in plasmaspheric EMIC waves. We investigated the ion composition ratio by characteristic frequencies of EN emissions and EMIC waves and obtained ion composition ratios. We found that the maximum composition ratio of M/Q= 2 ions is ~10% below 3,000 km. The quantitative estimation of the ion composition will contribute to improving the plasma model of the deep plasmasphere and the topside ionosphere. Equatorial noise (EN) emissions are whistler mode waves. Using Van Allen Probe and Arase (ERG) plasma wave data, we found that EN emissions propagate toward the Earth and are converted to electromagnetic ion cyclotron (EMIC) waves in the deep plasmasphere and the topside ionosphere. We suggest that minor ions with a mass per charge (M/Q) = 2, that is, deuteron or alpha particles, play an important role in this process. The processes reported here are a new generation process of plasmaspheric EMIC waves. Moreover, we determined the ion composition ratio using characteristics of wave dispersion. We derived the altitude profile of the ion composition ratio and identified the maximum ratio of M/Q= 2 ions of about 10% in the deep plasmasphere. The first measurements of the conversion from equatorial noise to EMIC waves are presentedExistence of M/Q= 2 ions (deuteron or alpha particle) in the deep plasmasphere is essential to cause the conversionThe ion composition ratio is quantitatively estimated in the deep plasmasphere using characteristics of the wave dispersion

The temporal modulations of magnetospheric chorus waves are one of the candidates for explaining quasiperiodic precipitation of energetic electrons causing pulsating aurora (PsA). To confirm fully the direct association between PsA and chorus, an extended interval of PsA (~1 hr) simultaneously observed by the Arase satellite and a ground‐based all‐sky imager in Apatity, Kola Peninsula, Russia was examined. In particular, a region of high correlation between PsA and chorus was continuously tracked within the field of view of the all‐sky imager. The result showed that the high‐correlation region and the modeled footprint of Arase moved in tandem. This strongly implies that the chorus and PsA electrons originated from the same local interaction region. In addition, the location of the high‐correlation region showed sudden jumps, which were probably associated with the motion of the satellite through discrete spatial structures of plasma in the region of wave‐particle interaction. Pulsating aurora (PsA), which consists of luminous patches/arcs blinking with various periodicities ranging from a few to a few tens of seconds, is known to occur very frequently during the recovery phase of auroral substorms. It has been suggested that the luminosity variation of PsA is controlled by natural electromagnetic waves in space, which are called chorus waves. There have been several studies that demonstrated one‐to‐one correspondence between the temporal variations of PsA and chorus waves. However, it is still unclear how long such a good correlation between PsA and chorus is preserved. In this study, an extended interval of PsA (~1 hr) simultaneously observed by a newly launched magnetospheric satellite, Arase, and a ground‐based high‐speed all‐sky imager in Apatity, Kola Peninsula, Russia was investigated. As a result, not only was the correspondence between PsA and chorus verified but also the motion of the high‐correlation region (correlation coefficient > 0.5) was successfully tracked in a continuous manner. The obtained long‐lasting reasonable correlation proves that the chorus waves control the luminosity variation of PsA. In addition, the region of high correlation between PsA and chorus showed sudden jumps, which could be caused by the motion or variation of the fine‐scale structure of the wave‐particle interaction region in space. Observation of the Arase satellite with an all‐sky imager revealed a long‐lasting correlation between pulsating aurora and chorus wavesThe high‐correlation region sometimes changed abruptly, which could have resulted from the discrete spatial structure of plasmaThe cross‐correlation analysis can be used for monitoring the local link between the ionosphere and magnetosphere

We report on deformation of electron pitch angle distributions associated with upper band chorus observed by the Arase satellite. The deformation is characterized by flux increase of 17–30 keV electrons in a narrow and oblique pitch angle range (65–80°) and by flux decrease in 7–17 keV electron flux in the smaller pitch angle range than the flux increase. Comparison of change in electron pitch angle distributions with resonant ellipses of the upper band chorus shows that the deformation appears where effective wave‐particle interaction is expected in the velocity space, and the flux increase takes place along the resonant ellipse of the upper frequency of the wave. This strongly suggests that the deformation is a consequence of wave‐particle interactions between electrons and upper band chorus. The Arase observation demonstrates that the deformation occurs within 30 s, which is faster than expected from the quasi‐linear diffusion theory. Wave‐particle interaction is a fundamental and universal process in space plasmas. It has been suggested that whistler mode chorus waves play crucial roles in the acceleration and loss of energetic electrons in geospace. Numerical simulations have shown that electron distribution function is rapidly deformed by chorus waves in association with the wave generation, while clear observational support has not been presented. On 20 December 2016, the Exploration of energization and Radiation in Geospace (ERG; also called “Arase”) satellite was launched. Medium Energy Particle experiment‐electron analyzer (MEP‐e) onboard the Arase satellite is the newly developed particle detector, which measures electrons in the energy range of 7–87 keV with good energy and angular resolutions as well as high detection efficiency compared to previous instruments. Based on observations by MEP‐e, this paper shows that electron distribution function is rapidly deformed in association with the appearance of chorus emissions. In cooperation with the simultaneous plasma wave measurement, MEP‐e reveals that the deformation is likely to result from acceleration and loss of electrons by chorus waves. The observed distribution is similar to that seen in the simulation result, suggesting that MEP‐e captures rapid deformation of electron distribution functions by wave‐particle interactions. The Arase satellite observed deformation of electron pitch angle distributions in conjunction with upper band chorusThe deformation is characterized by increase in 17–30 keV electron fluxes and decrease in fluxes in lower energy range within 30 sThe deformation appears where wave‐particle interactions with electrons and upper band chorus is expected in the velocity space

Auroral substorms, dynamic phenomena that occur in the upper atmosphere at night, are caused by global reconfiguration of the magnetosphere, which releases stored solar wind energy. These storms are characterized by auroral brightening from dusk to midnight, followed by violent motions of distinct auroral arcs that suddenly break up, and the subsequent emergence of diffuse, pulsating auroral patches at dawn. Pulsating aurorae, which are quasiperiodic, blinking patches of light tens to hundreds of kilometres across, appear at altitudes of about 100 kilometres in the high-latitude regions of both hemispheres, and multiple patches often cover the entire sky. This auroral pulsation, with periods of several to tens of seconds, is generated by the intermittent precipitation of energetic electrons (several to tens of kiloelectronvolts) arriving from the magnetosphere and colliding with the atoms and molecules of the upper atmosphere. A possible cause of this precipitation is the interaction between magnetospheric electrons and electromagnetic waves called whistler-mode chorus waves. However, no direct observational evidence of this interaction has been obtained so far. Here we report that energetic electrons are scattered by chorus waves, resulting in their precipitation. Our observations were made in March 2017 with a magnetospheric spacecraft equipped with a high-angular-resolution electron sensor and electromagnetic field instruments. The measured quasiperiodic precipitating electron flux was sufficiently intense to generate a pulsating aurora, which was indeed simultaneously observed by a ground auroral imager.

A physical mechanism to produce pulsating aurora (PsA) has been considered to be the interaction of the electron and the chorus wave generated near the equatorial plane of the magnetosphere. A recent observation of high temporal resolution of chorus waves by the Arase satellite revealed that the presence or absence of the internal modulation of PsA, which is a characteristic sub‐second scintillation at 3 ± 1 Hz within each optical pulsation, is closely related to the discreteness of the element structure of the chorus wave. However, it is still unclear what parameters (or conditions) control the discreteness of the element and the existence of the internal modulation of PsA. In this study, we discuss parameters that determine the presence or absence of the internal modulation of PsA and element structure of chorus by showing a conjugate observation of PsA/chorus by ground‐based cameras and the Arase satellite. During the event, the occurrence of internal modulation increased temporally. The wave data from the satellite show that the repetitive frequency of elements was ∼6 Hz when the internal modulation was indistinct, while the repetitive frequency was ∼3 Hz when the internal modulation was distinct. The particle measurements suggest that this difference was caused by changes in the density and the temperature anisotropy of the hot electron. The internal modulation was clearly observed when the density of hot electrons decreased and the temperature anisotropy relaxed after the injection. Observations of internal modulations from the ground might allow us to estimate the parameters such as energetic electron density and temperature anisotropy in the magnetosphere. We analyzed a pulsating aurora (PsA) event in which the occurrence frequency of internal modulation increased significantly with timeA conjugate observation with Arase suggests that a sudden enhancement of energetic electrons by the injection caused non‐modulated PsAsThe internal modulation may be more often observed after the injection as the density of energetic electrons decreases in the magnetosphere We analyzed a pulsating aurora (PsA) event in which the occurrence frequency of internal modulation increased significantly with time A conjugate observation with Arase suggests that a sudden enhancement of energetic electrons by the injection caused non‐modulated PsAs The internal modulation may be more often observed after the injection as the density of energetic electrons decreases in the magnetosphere

A specialized ground‐based system has been developed for simultaneous observations of pulsating aurora (PsA) and related magnetospheric phenomena with the Arase satellite. The instrument suite is composed of (a) six 100 Hz sampling high‐speed all‐sky imagers (ASIs), (b) two 10 Hz sampling monochromatic ASIs observing 427.8 and 844.6 nm auroral emissions, (c) a 20 Hz sampling fluxgate magnetometer. The 100 Hz ASIs were deployed in four stations in Scandinavia and two stations in Alaska, which have been used for capturing the main pulsations and quasi 3 Hz internal modulations of PsA at the same time. The 10 Hz sampling monochromatic ASIs have been operative in Tromsø, Norway with the 20 Hz sampling magnetometer. Combination of these multiple instruments with the European Incoherent SCATter (EISCAT) radar enables us to detect the low‐altitude ionization due to energetic electron precipitation during PsA and further to reveal the ionospheric electrodynamics behind PsA. Since the launch of the Arase satellite, the data from these instruments have been examined in comparison with the wave and particle data from the satellite in the magnetosphere. In the future, the system can be utilized not only for studies of PsA but also for other classes of aurora in close collaboration with the planned EISCAT_3D project. An integrated package of instruments for high‐time resolution measurements of pulsating aurora was deployed in Scandinavia and AlaskaThe system has enabled us to capture the fine‐scale spatio‐temporal variations of pulsating aurora in a wide areaData from those instruments have also been used for simultaneous observations of pulsating aurora with the Arase satellite An integrated package of instruments for high‐time resolution measurements of pulsating aurora was deployed in Scandinavia and Alaska The system has enabled us to capture the fine‐scale spatio‐temporal variations of pulsating aurora in a wide area Data from those instruments have also been used for simultaneous observations of pulsating aurora with the Arase satellite

A new empirical density model is developed for the inner zone between 1 < L< 3 using plasma densities inferred from the upper hybrid resonance on Arase, and hiss‐inferred density values from Van Allen Probes. The Van Allen Probes hiss‐inferred densities are first recalibrated and validated against Arase observations, using both a conjunction event and statistical analyses. The newly developed density model includes dependencies on L, magnetic latitude, and magnetic local time (MLT). Between 1.5 < L< 3.0, the equatorial density variation with Lis shown to be equivalent to that of the Ozhogin et al. (2012, https://doi.org/10.1029/2011JA017330) model. However, for L< 1.5, this dependence changes as the plasma density increases at a faster rate with decreasing L. The latitudinal dependence of the plasma density is shown to present a flatter profile than previous models, meaning lower densities extend to higher latitudes. This dependence is well‐modeled by updated fitting coefficients. A clear MLT dependence of the plasma density is identified, which was not found or included in some previous models. This variation is consistent with the diurnal variation of the ionosphere, peaking near MLT = 14 and becoming larger in amplitude with decreasing L. A function describing this MLT dependence is presented. Overall, the new L, latitude, and MLT‐dependent empirical model can provide density values in areas outside the validity region of many previous models, making it a useful resource for accurately determining diffusion coefficients and predicting electron dynamics and their lifetimes in the inner radiation belt. Radiation Belt Storm Probes and Arase data are used to build a new empirical plasma density model for the inner zone, including L, latitude, and magnetic local time (MLT) dependenciesMLT dependence consistent with diurnal variation of ionosphere. Variation is largest in amplitude at low L, but persists out to L= 3New model provides density in areas outside previous model bounds, making it a useful resource for modeling inner radiation belt dynamics Radiation Belt Storm Probes and Arase data are used to build a new empirical plasma density model for the inner zone, including L, latitude, and magnetic local time (MLT) dependencies MLT dependence consistent with diurnal variation of ionosphere. Variation is largest in amplitude at low L, but persists out to L= 3 New model provides density in areas outside previous model bounds, making it a useful resource for modeling inner radiation belt dynamics

We propose an accurate calibration method for short‐time waveform signals passed through a linear time‐invariant (LTI) system that has a non‐negligible group delay. Typically, the calibration process of waveform data is expressed by the deconvolution in the time domain, and there is an equivalent operation in the frequency domain with the Fourier transform. For the short‐time data, if the short‐time Fourier transform is applied to the waveform data in the calibration process, multiplying the data by a window function is highly recommended to reduce side‐lobe effects. However, the multiplied window function is also modified in the calibration process. We analyzed the modification mathematically and derived a method to eliminate the modification of the multiplied window function. In the method, calibrated data in the frequency domain are inverse‐transformed into waveform data at each frequency, divided by a modified window function at each frequency, and accumulated over the frequencies. The principle of this method derived quantitatively indicates that the calibration accuracy depends on the transfer function of the system, frequency resolution of the Fourier transform, type of the window function, and typical frequency of the waveform data. Compared with conventional calibration methods, the proposed method provides more accurate results in various cases. This method should be useful for the calibration of general radio wave signals passed through LTI systems as well as for the calibration of plasma waves observed in space. We propose a calibration method using short‐time Fourier transform (STFT) for waveform data, such as plasma waves observed in spaceThe accuracy of the method is evaluated using the transfer functions of well‐known filters and frequency‐fixed sinusoidal waveformsThe proposed method provides the most accurately calibrated data compared with conventional methods using STFT We propose a calibration method using short‐time Fourier transform (STFT) for waveform data, such as plasma waves observed in space The accuracy of the method is evaluated using the transfer functions of well‐known filters and frequency‐fixed sinusoidal waveforms The proposed method provides the most accurately calibrated data compared with conventional methods using STFT

Microbursts are impulsive (<1 s) injections of electrons into the atmosphere, thought to be caused by nonlinear scattering by chorus waves. Although attempts have been made to quantify their contribution to outer belt electron loss, the uncertainty in the overall size and duration of the microburst region is typically large, so that their contribution to outer belt loss is uncertain. We combine datasets that measure chorus waves (Van Allen Probes [RBSP], Arase, ground‐based VLF stations) and microburst (>30 keV) precipitation (FIREBIRD II and AC6 CubeSats, POES) to determine the size of the microburst‐producing chorus source region beginning on 5 December 2017. We estimate that the long‐lasting (∼30 hr) microburst‐producing chorus region extends from 4 to 8 Δ${\Delta}$MLT and 2–5 Δ${\Delta}$L. We conclude that microbursts likely represent a major loss source of outer radiation belt electrons for this event. Microbursts are short‐duration (<1 s) bursts of electrons that precipitate from the magnetosphere into the atmosphere. Microbursts are thought to be a result of scattering by a plasma wave called chorus. Attempts have been made to understand the contribution microburst precipitation has on electron loss, which helps the outer radiation belt recover after enhancements during storms. The contribution depends on the overall size and duration of the microburst region. We combine datasets that measure chorus waves and microburst precipitation to determine the size and duration of a microburst region beginning on 5 December 2017. Our results show that microbursts are likely a significant source of electron loss. We use multipoint observations to estimate the size of a long‐lasting microburst‐producing chorus region beginning on 5 December 2017We estimate that the microburst‐producing chorus region for this event extends from 4 to 8 Δ${\Delta}$MLT and 2–5 Δ${\Delta}$LMicroburst precipitation from this event likely constitutes a major source of electron loss from the outer radiation belt We use multipoint observations to estimate the size of a long‐lasting microburst‐producing chorus region beginning on 5 December 2017 We estimate that the microburst‐producing chorus region for this event extends from 4 to 8 Δ${\Delta}$MLT and 2–5 Δ${\Delta}$L Microburst precipitation from this event likely constitutes a major source of electron loss from the outer radiation belt

Plasmaspheric hiss can cause energetic electron precipitation from the magnetosphere to the Earth's upper atmosphere and affect the ionospheric electron density profiles. In this study, we use Arase satellite measurements in the dayside plasmasphere to model the electron precipitation and the resultant ionospheric response, and compare the results to the electron density measured by the Poker Flat Incoherent Scatter Radar (PFISR). We analyzed two close conjunction events between Arase and PFISR at L∼ 6 in the afternoon sector, when Arase was in the outer plasmasphere and traveled into the plasmaspheric plumes. Modest or strong hiss waves were observed with amplitudes higher than 50 pT during both events. Quasilinear modeling suggests that the hiss waves could cause intense electron precipitation ranging from several keV to several hundred keV energies. The electron density profiles at 60–90 km modeled by the Boulder Electron Radiation to Ionization (BERI) model suggest significant electron density enhancements due to the precipitating electrons. PFISR simultaneously observed electron density enhancements during both events, and provided evidence for the electron precipitation at altitudes down to <70 km. The temporal modulation of hiss caused the modulated density profiles in BERI modeling, but was not evident in PFISR observations. The modeled altitude profiles of the perturbed electron density overall agree with PFISR observation. At altitudes below 75 km, the modeled electron densities are lower than the observation, suggesting additional high energy electron precipitation possibly due to low frequency (<50 Hz) waves or hiss wave powers ducted to high latitudes. Two Poker Flat Incoherent Scatter Radar (PFISR)‐Arase conjunction events are identified at the dayside plasmasphere when hiss wave amplitudes reach 50–100 pT at L∼ 6Hiss‐driven electron precipitation obtained from quasilinear simulation is used to model ionospheric density profiles at 60–90 km altitudeModeled electron densities overall agree with PFISR observations with differences in the temporal modulation and at altitudes below 75 km Two Poker Flat Incoherent Scatter Radar (PFISR)‐Arase conjunction events are identified at the dayside plasmasphere when hiss wave amplitudes reach 50–100 pT at L∼ 6 Hiss‐driven electron precipitation obtained from quasilinear simulation is used to model ionospheric density profiles at 60–90 km altitude Modeled electron densities overall agree with PFISR observations with differences in the temporal modulation and at altitudes below 75 km

An ion cyclotron whistler is a left‐handed polarized electromagnetic ion cyclotron mode wave converted from a lightning electron whistler. Some ion cyclotron whistlers have been identified as deuteron whistlers. This paper reports M/Q= 2 ion cyclotron whistlers observed by the Akebono satellite in the altitude region around 3200–10000 km (L= 1.5–3.4), which is a considerably higher altitude than those previously reported. This evidence indicates that M/Q= 2 ions are present not only in the low‐altitude region but also in the inner magnetosphere around L= 3.4. We estimated the ion concentration from the crossover frequency of the M/Q= 2 ion cyclotron whistler wave observed in the altitude region around 4200 km (L= 1.7) and concluded that the concentration of M/Q= 2 ions was plausibly up to 12.6% during this event. Our observation results give important clues to study unknown minor ion profiles such as circulation mechanism of deuterons or injection mechanism of alpha particles in the solar wind. M/Q=2 ion cyclotron whistlers were observed by AkebonoThey were discovered at a higher altitude than those previously reportedExistence of certain amounts of M/Q=2 ions around L=1.5–3.4 is demonstrated

It is well known that electromagnetic ion cyclotron (EMIC) waves exhibit characteristic frequencies on the basis of dispersion relations in multiple‐component plasma. We present a case of EMIC waves exhibiting a sudden decrease in intensity (characteristic lower cutoff) to just above half of the proton cyclotron frequency observed in the vicinity of the geomagnetic equator by the Akebono satellite along its trajectory during a magnetic storm in April 1989. It was found that the waves propagate with a large wave normal angle with respect to the geomagnetic field line and that they had a crossover frequency above the characteristic lower cutoff. Because of stormy conditions, ion constituents were expected to fluctuate, suggesting that the characteristic frequencies of EMIC waves should have been fluctuating as well. However, the characteristic frequencies of each event did not vary despite disturbances in the inner magnetosphere, represented by a sudden decrease in the Dstindex and electron density fluctuation. In addition, the waves were repeatedly observed within a half day after sudden decreases in Dst; however, they disappeared when the recovery of the Dstindex became moderate. Wave generation appears to be closely correlated to fresh energetic particle injection. We study the dispersion relations of EMIC waves under the condition of multiple ion species and suggest the existence of a few percent of alpha particles (He++) or deuterons (D+), which can explain the lower cutoff of EMIC waves in the inner magnetosphere. EMIC waves which had characteristic cutoff frequency were observed by AkebonoCutoff frequencies are stable in spite of disturbance of inner magnetosphereExistence of a few percent of He++ is suggested in the inner magnetosphere

Peel adhesive strengths of multi-layered laminates composed of two polypropylene (PP) sheets and an inserted polyethylene (PE) layer (the middle layer) between the PP layers were evaluated. PE-glycidyl methacrylate (GMA) copolymers and a maleic-anhydride grafted PP (MAPP) were compared to the PE homopolymer and the PP homopolymer. The peel adhesive strength of PE-GMA/MAPP laminates was much higher than that of PE homopolymer/PP homopolymer laminates. Meanwhile, the blends composed of the PE-GMA and three types of PE homopolymer (PE-GMA+LDPE, PE-GMA+MDPE, PE-GMA+HDPE) were formulated as the PE middle layer of the multi-layered laminates. The PE blends had the same amount of glycidyl groups, and the deformation capacity was different in each. Namely, the PE blend of LDPE had higher elongation to break than the PE blend of HDPE. The peel adhesive strength of the multi-layered laminates with the middle layer of the LDPE blend was highest among the three types of laminates with the middle layer of the PE blends. Scanning electron microscopy on the fractured surfaces revealed that the large plastic deformation of the LDPE blended middle layer was responsible for the high energy absorption, and resulted in the high peel strength.

In posterior stabilised total knee replacement (TKR) a larger femoral component is sometimes selected to manage the increased flexion gap caused by resection of the posterior cruciate ligament. However, concerns remain regarding the adverse effect of the increased anteroposterior dimensions of the femoral component on the patellofemoral (PF) joint. Meanwhile, the gender-specific femoral component has a narrower and thinner anterior flange and is expected to reduce the PF contact force. PF contact forces were measured at 90°, 120°, 130° and 140° of flexion using the NexGen Legacy Posterior Stabilized (LPS)-Flex Fixed Bearing Knee system using Standard, Upsized and Gender femoral components during TKR. Increasing the size of the femoral component significantly increased mean PF forces at 120°, 130° and 140° of flexion (p = 0.005, p < 0.001 and p < 0.001, respectively). No difference was found in contact force between the Gender and the Standard components. Among the patients who had overhang of the Standard component, mean contact forces with the Gender component were slightly lower than those of the Standard component, but no statistical difference was found at 90°, 120°, 130° or 140° of flexion (p = 0.689, 0.615, 0.253 and 0.248, respectively).Upsized femoral components would increase PF forces in deep knee flexion. Gender-specific implants would not reduce PF forces.

We investigated whether the extension gap in total knee replacement (TKR) would be changed when the femoral component was inserted. The extension gap was measured with and without the femoral component in place in 80 patients with varus osteoarthritis undergoing posterior-stabilised TKR. The effect of a post-operative increase in the size of the femoral posterior condyles was also evaluated. The results showed that placement of the femoral component significantly reduced the medial and lateral extension gaps by means of 1.0 mm and 0.9 mm, respectively (p < 0.0001). The extension gap was reduced when a larger femoral component was selected relative to the thickness of the resected posterior condyle. When the post-operative posterior lateral condyle was larger than that pre-operatively, 17 of 41 knees (41%) showed a decrease in the extension gap of > 2.0 mm. When a specially made femoral trial component with a posterior condyle enlarged by 4 mm was tested, the medial and lateral extension gaps decreased further by means of 2.1 mm and 2.8 mm, respectively.If the thickness of the posterior condyle is expected to be larger than that pre-operatively, it should be recognised that the extension gap is likely to be altered. This should be taken into consideration when preparing the extension gap.

Background: High plasma levels of C‐reactive protein (CRP) constitute a powerful predictive marker of cardiovascular events. Several lines of evidence suggest that CRP has prothrombogenic effects. However, whether CRP directly participates in the pathogenesis of thrombosis in vivo has not been fully clarified. Objective: To test whether human CRP (hCRP) affects arterial thrombus formation after balloon injury of smooth muscle cell (SMC)‐rich or macrophage‐rich neointima. Methods: We compared the susceptibility of transgenic (Tg) rabbits expressing hCRP (46.21 ± 13.85 mg L−1, n = 22) and non‐Tg rabbits to arterial thrombus formation after balloon injury of SMC‐rich or macrophage‐rich neointima. Results: Thrombus size on SMC‐rich or macrophage‐rich neointima was significantly increased, and was accompanied by an increase in fibrin content in hCRP‐Tg rabbits, as compared with non‐Tg rabbits. Thrombus size did not significantly differ between SMC‐rich and macrophage‐rich neointima in hCRP‐Tg rabbits. Tissue factor (TF) mRNA expression and activity in these neointimal lesions were significantly increased in hCRP‐Tg rabbits as compared with non‐Tg rabbits. The degree of CRP deposition correlated with the elevated TF expression and thrombus size on injured neointima. In addition, hCRP isolated from hCRP‐Tg rabbit plasma induced TF mRNA expression and activity in rabbit cultured vascular SMCs. Conclusions: These results suggest that elevated plasma hCRP levels promote thrombus formation on injured SMC‐rich neointima by enhancing TF expression, but have no additive effects in macrophage‐rich neointima.

Background: Plaque erosion is a cause of atherothrombosis that preferentially occurs on smooth muscle cell (SMC)‐ and proteoglycan‐rich rather than lipid‐rich plaques. However, its underlying mechanisms remain unknown. Objective: To determine whether disturbed blood flow induces erosive injury and thrombus formation on SMC‐rich neointima. Methods: Three weeks after balloon injury, SMC‐rich neointima with increased tissue factor (TF) activity developed in rabbit femoral arteries that were narrowed with a vascular occluder to disturb blood flow after stenosis. Neointimal injury and thrombus formation were assessed at 15, 30, and 180 min after the vascular narrowing. Results: Endothelial detachment, platelet adhesion and neointimal cell apoptosis became evident at the post‐stenotic regions of all femoral arteries (n = 5) within 15 min of narrowing. Mural thrombi composed of platelet and fibrin developed after 30 min, and then occlusive thrombi were generated in three out of five vessels after 180 min. The identical vascular narrowing of normal femoral arteries also induced endothelial detachment with small platelet thrombi at post‐stenotic regions, but fibrin and occlusive thrombi did not develop. Computational simulation analysis indicated that oscillatory shear stress contributes to the development of erosive damage to the neointima. Conclusions: These results suggest that disturbed post‐stenotic blood flow can induce erosive injury in SMC‐rich plaques and promote thrombus formation that results in vascular events.

Inner magnetospheric electrons are precipitated in the ionosphere via pitch‐angle (PA) scattering by lower band chorus (LBC), upper band chorus (UBC), and electrostatic electron cyclotron harmonic (ECH) waves. However, the PA scattering efficiency of low‐energy electrons (0.1–10 keV) has not been investigated via in situobservations because of difficulties in flux measurements within loss cones at the magnetosphere. In this study, we demonstrate that LBC, UBC, and ECH waves contribute to PA scattering of electrons at different energy ranges using the Arase (ERG) satellite observation data and successively detected the moderate loss cone filling, that is, approaching strong diffusion. Approaching strong diffusion by LBC, UBC, and ECH waves occurred at ∼2–20 keV, ∼1–10 keV, and ∼0.1–2 keV, respectively. The occurrence rate of the approaching strong diffusion by high‐amplitude LBC (>50 pT), UBC (>20 pT), and ECH (>10 mV/m) waves, respectively, reached ∼70%, ∼40%, and ∼30% higher than that without simultaneous wave activity. The energy range in which the occurrence rate was high agreed with the range where the PA diffusion rate of each wave exceeded the strong diffusion level based on the quasilinear theory. The pitch‐angle scattering efficiencies by plasma waves are statistically investigated using in situobservationsLower band chorus waves caused approaching strong diffusion with the highest occurrence rate in the energy range of ∼2–20 keVElectrostatic electron cyclotron harmonic waves could contribute approaching strong diffusion in the ∼0.1–1 keV energy range The pitch‐angle scattering efficiencies by plasma waves are statistically investigated using in situobservations Lower band chorus waves caused approaching strong diffusion with the highest occurrence rate in the energy range of ∼2–20 keV Electrostatic electron cyclotron harmonic waves could contribute approaching strong diffusion in the ∼0.1–1 keV energy range

Mechanical failure because of wear or fracture of the polyethylene tibial post in posteriorly-stabilised total knee replacements has been extensively described. In this study of 12 patients with a clinically and radiologically successful NexGen LPS posteriorly-stabilised prosthesis impingement of the anterior tibial post was evaluated in vivo in three dimensions during gait using radiologically-based image-matching techniques.Impingement was observed in all images of the patients during the stance phase, although the NexGen LPS was designed to accommodate 14° of hyperextension of the component before impingement occurred. Impingement arises as a result of posterior translation of the femur during the stance phase. Further attention must therefore be given to the configuration of the anterior portion of the femoral component and the polyethylene post when designing posteriorly-stabilised total knee replacements.

We compared the alignment of 39 total knee replacements implanted using the conventional alignment guide system with 37 implanted using a CT-based navigation system, performed by a single surgeon. The knees were evaluated using full-length weight-bearing anteroposterior radiographs, lateral radiographs and CT scans.The mean hip-knee-ankle angle, coronal femoral component angle and coronal tibial component angle were 181.8° (174.2° to 188.3°), 88.5° (84.0° to 91.8°) and 89.7° (86.3° to 95.1°), respectively for the conventional group and 180.8° (178.2° to 185.1°), 89.3° (85.8° to 92.0°) and 89.9° (88.0° to 93.0°), respectively for the navigated group.The mean sagittal femoral component angle was 85.5° (80.6° to 92.8°) for the conventional group and 89.6° (85.5° to 94.0°) for the navigated group.The mean rotational femoral and tibial component angles were -0.7° (-8.8° to 9.8°) and -3.3° (-16.8° to 5.8°) for the conventional group and -0.6° (-3.5° to 3.0°) and 0.3° (-5.3° to 7.7°) for the navigated group.The ideal angles of all alignments in the navigated group were obtained at significantly higher rates than in the conventional group. Our results demonstrated significant improvements in component positioning with a CT-based navigation system, especially with respect to rotational alignment.

The high-temperature oxidation in air and steam at 923 K was examined with pure iron, Fe-10Cr and Fe-10Cr-0.08C (0~0.03)S steels. The amount of hydrogen dissolved into samples during exposure to steam was measured with thermal desorption spectroscopy (TDS). It was found that the amount of dissolved hydrogen was related closely to the steam oxidation resistance of the steels. In case of pure iron, the thickness of the oxide scale formed in steam at 923 K for 360 ks was comparable to that of the scale formed in air. On the other hand, in case of the Fe-Cr binary alloy and the ternary ferritic steel, the oxide scale was much thicker in steam than in air. It was found that the amount of the dissolved hydrogen was much larger in both the binary alloy and the ternary ferritic steel than in pure iron, and then it leads to the more accelerated oxidation rate in the ternary steels in steam.

Electron microscopic investigation on osteogenetic process at the implant surface of threadless rod-type titanium implants with different surface roughness of Ra 0.4 ± 0.01 μm, Sm 2.6 ± 0.3 μm and Ra 2.0 ± 0.12 μm, Sm 36 ± 9.1 μm was performed at the early stage of 21 and 42 days post implantation into the jawbones of four beagles under the load bearing condition of functional mastication. The implant surfaces were covered with a blood clot and haematopoietic stem cells (HSC) including phagocytic monocytes immediately after the implantation. Successively, osteogenic stem cells (OSC) migrated from cortical and/or trabecular endosteum to the HSC-layer on the implant surface. The new bone formation at the implant/bone marrow interface was developed by collaboration of osteomediator cells (OMC) differentiated from monocytes of HSC and osteoblast phenotype cells of OSC derived from endosteum of cortical bone and/or trabecular. The new bone layer at the implant surface consisted of two layers, solution-mediated calcification layer of pseudo bone and cell (osteoblast) -mediated calcification layer of true bone. The pseudo bone was produced by solution-mediated calcification of OMC- and HSC-remnants near by the implant surface. The bone healing process at the implant/bone marrow interface depended upon two factors; the migration of OSC from cortical and/or trabecular endosteum to the implant surface and the healing potentiality. Topographic dependency upon the bone healing potential at implant/bone marrow interface was not confirmed in this experiment under the load bearing condition of functional mastication.Electron microscopic investigation on osteogenetic process at the implant surface of threadless rod-type titanium implants with different surface roughness of Ra 0.4 ± 0.01 μm, Sm 2.6 ± 0.3 μm and Ra 2.0 ± 0.12 μm, Sm 36 ± 9.1 μm was performed at the early stage of 21 and 42 days post implantation into the jawbones of four beagles under the load bearing condition of functional mastication. The implant surfaces were covered with a blood clot and haematopoietic stem cells (HSC) including phagocytic monocytes immediately after the implantation. Successively, osteogenic stem cells (OSC) migrated from cortical and/or trabecular endosteum to the HSC-layer on the implant surface. The new bone formation at the implant/bone marrow interface was developed by collaboration of osteomediator cells (OMC) differentiated from monocytes of HSC and osteoblast phenotype cells of OSC derived from endosteum of cortical bone and/or trabecular. The new bone layer at the implant surface consisted of two layers, solution-mediated calcification layer of pseudo bone and cell (osteoblast) -mediated calcification layer of true bone. The pseudo bone was produced by solution-mediated calcification of OMC- and HSC-remnants near by the implant surface. The bone healing process at the implant/bone marrow interface depended upon two factors; the migration of OSC from cortical and/or trabecular endosteum to the implant surface and the healing potentiality. Topographic dependency upon the bone healing potential at implant/bone marrow interface was not confirmed in this experiment under the load bearing condition of functional mastication.

In vitro studies have proved the topographic dependency upon osteogenesis on titanium plate by investigating the cell-adhesion, -shape, -proliferation, -differentiation, ALP activity and osteocalcin production of osteogenic stem cells, MG36, MC3T3-E1 and wild strains of bone formative cells from animal and human. However, this in vivo study on bone growth around cp titanium dental implants under masticatory loading did not demonstrate significant difference among the different surface roughness in the range of Ra 0.4–1.9 μm, Rz 2.8–11.2 μm, Rmax 3.6–28.1 μm and Sm 2.9–41.0 μm, which was estimated by measuring the bone contacts, bone occupancies and bone bonding strengths at the implant/bone marrow interface.In vitro studies have proved the topographic dependency upon osteogenesis on titanium plate by investigating the cell-adhesion, -shape, -proliferation, -differentiation, ALP activity and osteocalcin production of osteogenic stem cells, MG36, MC3T3-E1 and wild strains of bone formative cells from animal and human. However, this in vivo study on bone growth around cp titanium dental implants under masticatory loading did not demonstrate significant difference among the different surface roughness in the range of Ra 0.4–1.9 μm, Rz 2.8–11.2 μm, Rmax 3.6–28.1 μm and Sm 2.9–41.0 μm, which was estimated by measuring the bone contacts, bone occupancies and bone bonding strengths at the implant/bone marrow interface.

We have previously developed a radiographic technique, the oblique posterior condylar view, for assessment of the posterior aspect of the femoral condyles after total knee arthroplasty. The purpose of this study was to confirm the validity of this radiographic view based upon intra-operative findings at revision total knee arthroplasty. Lateral and oblique posterior condylar views were performed for 11 knees prior to revision total knee arthroplasty, and radiolucent lines or osteolysis of the posterior aspect of the femoral condyles were identified. These findings were compared with the intra-operative appearance of the posterior aspects of the femoral condyles. Statistical analysis showed that sensitivity and efficacy were significantly better for the oblique posterior condylar than the lateral view. This method can, therefore, be considered as suitable for routine follow-up radiographs of the femoral component and in the pre-operative planning of revision surgery.

Clathrate hydrate formation in a (methane + either 3-methyltetrahydropyran or 2-methyltetrahydrofuran + water) system is demonstrated. The first data of the quadruple (water + structure-H hydrate + either 3-methyltetrahydropyran or 2-methyltetrahydrofuran + methane) equilibrium pressure–temperature conditions are measured over temperatures from 273 to 286 K. In the 3-methyltetrahydropyran system, the equilibrium pressures are lower by 1.6–2 MPa than those of the structure-I methane hydrate formed in the methane + water system at given temperatures. In the 2-methyltetrahydrofuran system, equilibrium pressures at temperatures below 278 K are lower than those for the structure-I methane hydrate, and at temperatures above 278 K, they are higher. These phase equilibria suggest the formation of hydrates other than structure-I methane hydrates in the two systems. The crystallographic structures of the hydrates are determined to be structure H by means of X-ray diffraction as expected from considerations of sizes and shapes of the 3-methyltetrahydropyran and 2-methyltetrahydrofuran molecules

Abstract The impact of radiation damage on the device performance of 4H-SiC Schottky diodes, which are irradiated at room temperature with 2-MeV electrons is studied. After irradiation the reverse current increases, while the forward current and the capacitance decrease with barrier height and carrier density. The decrease of the barrier height is mainly responsible for the increase of the reverse current, while the decrease of the forward current for a high fluence is caused by the increase of the resistance in the bulk of the crystal. Although no electron capture levels are observed before irradiation, three electron capture levels (E1, E2, and E3) are induced after irradiation. It is noted that the decrease in carrier density is partly caused by the contribution of non-observed electron capture level in the DLT spectrum, which compensates the free carriers.

Four-phase (ice + structure-H hydrate + large-molecule guest substance liquid + methane-rich vapor) equilibrium pressure−temperature conditions were measured at temperatures from 252 K to 272 K in systems of water + methane + LMGS, where LMGS is a large-molecule guest substance for a structure-H hydrate. The tested LMGSs were 2,2-dimethylbutane (neohexane), methylcyclohexane, and tert-butyl methyl ether. The results obtained in the 2,2-dimethylbutane system agree with the corresponding data reported by Makogon et al., which were the only data set on the structure-H hydrate phase equilibrium at temperatures below the freezing point of water. Among the three systems studied, the lowest equilibrium pressure at a given temperature was observed in the 2,2-dimethylbutane system, and the highest, in the tert-butyl methyl ether system.

We measured the contact areas and contact stresses at the post-cam mechanism of a posterior-stabilised total knee arthroplasty when a posterior force of 500 N was applied to the Kirschner Performance, Scorpio Superflex, NexGen LPS Flex Fixed, and NexGen LPS Flex Mobile knee systems. Measurements were made at 90°, 120°, and 150° of flexion both in neutral rotation and 10° of internal rotation of the tibial component. Peak contact stresses at 90°, 120°, and 150° were 24.0, 33.9, and 28.8 MPa, respectively, for the Kirschner; 26.0, 32.4, and 22.1 MPa, respectively, for the Scorpio; and 34.1, 31.5, and 32.5 MPa, respectively, for the NexGen LPS Flex Fixed. With an internally rotated tibia, the contact stress increased significantly with all the fixed-bearing arthroplasties but not with the NexGen LPS Flex Mobile arthroplasty. The post-cam design should be modified in order to provide a larger contact area whilst avoiding any impingement and edge loading.

After focal cerebral ischemia, the infarct volume increases rapidly within acute infarct expansion (initial 12 to 24 h) and continues slowly during delayed infarct expansion (25 to 168 h). While acute infarct expansion represents progressive necrosis within the ischemic core, delayed infarct expansion starts as disseminated apoptotic cell death in a narrow rim surrounding the infarct border, which gradually coalesces to form a larger infarct. Discovery of a distinct correlation between reactive astrogliosis along the infarct border and delayed infarct expansion in the rodent ischemia model led us to investigate the possible causal relationship between the two events. Specifically, the calcium binding protein S100B exerts detrimental effects on cell survival through activation of various intracellular signaling pathways, resulting in altered protein expression. Arundic acid [(R)-(-)-2-propyloctanoic acid, ONO-2506] is a novel agent that inhibits S100B synthesis in cultured astrocytes. In the rodent ischemia model, this agent was shown to inhibit both the astrocytic overexpression of S100B and the subsequent activation of signaling pathways in the peri-infarct area. Concurrently, delayed infarct expansion was prevented, and neurologic deficits were promptly ameliorated. The results of subsequent studies suggest that the efficacy of arundic acid is mediated by restoring the activity of astroglial glutamate transporters via enhanced genetic expression.

Our study evaluated the accuracy of an image-guided total knee replacement system based on CT with regard to preparation of the femoral and tibial bone using nine limbs from five cadavers. The accuracy was assessed by direct measurement using an extramedullary alignment rod without radiographs.The mean angular errors of the femur and tibia, which represent angular gaps from the real mechanical axis in the coronal plane, were 0.3° and 1.1°, respectively. The CT-based system, provided almost perfect alignment of the femoral component with less than 1° of error and excellent alignment with less than 3° of error for the tibial component. Our results suggest that standardisation of knee replacement by the use of this system will lead to improved long-term survival of total knee arthroplasty.

Small-molecule oxidosqualene cyclase (OSC) inhibitors were found to be effective in assays against cloned OSC-like enzymes from human pathogens. A combinatorial library was prepared and used to identify lead compounds that inhibit the growth of Trypanosoma cruzi, Leishmania mexicana amazonensis, and Pneumocystis carinii in culture. Selectivity for the microorganisms in preference to mammalian cells was observed.

Steroid receptors activate transcription in yeast cells via interactions with endogenous coactivators and/or basal factors. We examined the effects of mutations in the ligand binding domain on the transcriptional activity of ERalpha in yeast. Our results show that mutations in Helix 3 (K366A) and Helix 12 (M547A, L548A) disrupt transcriptional activity of ERalpha in yeast, as previously observed in mammalian cells. However, replacement of a conserved tyrosine residue in Helix 12 with alanine or aspartate (Y541A and Y541D), which renders ERalpha constitutively active in mammalian cells, had only a weak stimulatory effect on ligand-independent reporter activation by ERalpha in yeast. Two-hybrid interaction experiments revealed that a Y541A mutant expressed in yeast was capable of ligand-independent binding to a mammalian coactivator, suggesting that there is a subtle difference in how this mutant interacts with mammalian and yeast cofactors. We also show that the ligand-dependent activities of ERalpha and progesterone receptor (PR) in yeast cells were strongly enhanced by the human p160 protein steroid receptor coactivator (SRC1), but not by CREB-Binding Protein (CBP) or the p300/CBP associated factor (P/CAF). Although the SRC1 activation domains AD1 and AD2 are functional in yeast, deletion of these sequences only partially impaired SRC1 coactivator function in this organism; this is in contrast to similar experiments in mammalian cells. Thus SRC1 sequences involved in recruitment of CBP/p300 and Co-Activator-Associated Arginine Methyltransferase (CARM-1) in mammalian cells are not essential for its function in yeast, suggesting that SRC1 operates via distinct mechanisms in yeast and mammalian cells.

Presented here is a metabolically engineered yeast strain that produces sesquiterpenes. Epi-cedrol synthase expressed in a native yeast strain converted endogenous farnesyl pyrophosphate to 90 μg/L epi-cedrol. This system was genetically modified to increase foreign terpene yields to 370 μg/L. The best yields were obtained by overexpressing a truncated 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in a upc2-1 mating type a background. This system allows sufficient production to characterize novel sesquiterpene synthase genes.

Sixty yeast strains were previously screened for their ability to produce acetic acid, in shaken flask batch culture, from either glucose or ethanol. Seven of the strains belonging to the Brettanomycesand Dekkeragenera, from the ARS Culture Collection, Peoria, IL, were further evaluated for acetic acid production in bioreactor batch culture at 28 °C, constant aeration (0.75 v/v/m) and pH (6.5). The medium contained either 100 g glucose/l or 35 g ethanol/l as the carbon/energy source. Dekkera intermediaNRRL YB-4553 produced 42.8 and 14.9 g acetic acid/l from the two carbon sources, respectively, after 64.5 h. The optimal pH was determined to be 5.5. When the initial glucose concentration was 150 or 200 g/l, the yeast produced 57.5 and 65.1 g acetic acid/l, respectively.

Cycloartenol synthase cyclizes and rearranges oxidosqualene to the protosteryl cation and then specifically deprotonates from C-19. To identify mutants that deprotonate differently, randomly generated mutant cycloartenol synthases were selected in a yeast lanosterol synthase mutant. A novel His477Asn mutant was uncovered that produces 88% lanosterol and 12% parkeol. The His477Gln mutant produces 73% parkeol, 22% lanosterol, and 5% Δ⁷-lanosterol. These are the most accurate lanosterol synthase and parkeol synthase that have been generated by mutagenesis.

Abstract:  Multicentric reticulohistiocytosis is a rare systemic disease characterized by the infiltration of histiocytes and multinucleated giant cells with cutaneous nodules, and severe destructive arthritis. It is commonly the peripheral joints which are affected, and therefore symptoms in large joints have not been fully investigated. We describe the case of a 44-year-old woman with multicentric reticulohistiocytosis, who was suffering from swelling in both knee joints and cutaneous nodules, in addition to arthritis in the elbow, hip, and peripheral joints. Magnetic resonance imaging of both knee joints showed hydrarthrosis associated with a tumor-like overgrowth of synovial tissue. These symptoms were reduced following a resection of the synovial tissue and subsequent medication with prednisone and low-dose methotrexate. It should be noted that swelling in the knee joints can be one of the symptoms caused by multicentric reticulohistiocytosis, in addition to cutaneous nodules and arthritis in the peripheral joints. Resection of synovial tissue, and medication with prednisone and low-dose methotrexate were effective in the present case.

To determine the possible role of eosinophils in Angiostrongylus costaricensisinfection, both interleukin-5 (IL-5) transgenic (Tg) and non-transgenic (non-Tg) C3H/HeN mice were infected with A. costaricensisthird-stage larvae. IL-5 Tg mice demonstrated greater resistance than non-Tg mice to A. costaricensis, as shown by lower adult worm recovery, smaller adults, fewer eggs in the intestinal wall and fewer larvae passed in the feces. Both mice showed similar antigen-specific IgA and IgGl antibody responses, although IgA was more prominent than IgGl. Egg deposition and inflammatory responses in the intestinal walls were milder in IL-5 Tg mice than in non-Tg mice. The eggs with developed larvae, deposited in the intestinal walls of IL-5 Tg mice, were surrounded by numerous degranulating eosinophils and sometimes with Splendore–Hoeppli deposits. The data suggest that eosinophils are involved in the resistance of the mouse during primary infection with A. costaricensis.

Cycloartenol synthase converts oxidosqualene to cycloartenol, a pentacyclic isomer of the animal and fungal sterol precursor lanosterol. We used directed evolution to find cycloartenol synthase residues that affect cyclopropyl ring formation, selecting randomly generated cycloartenol synthase mutants for their ability to genetically complement a yeast strain lacking lanosterol synthase. To increase the likelihood of finding novel mutations, the little-studied Dictyostelium discoideum cycloartenol synthase was used for the mutagenesis. Several catalytically important residues were identified.

The immunohistochemical expression of β-catenin, cyclin D1, Ki-67 and PCNA was Examined in 38 cases of sporadic extra-abdominal or abdominal-wall desmoid tumours without familial adenomatous polyposis (FAP), to evaluate the hypothesis that the accumulated β-catenin within the nuclei could affect the regulation of the cyclin D1 gene. There was a statistically significant correlation between β-catenin accumulation and cyclin D1 overexpression (p=0.029). Each group with β-catenin accumulation or cyclin D1 overexpression showed a higher PCNA-LI than those without, the difference being statistically significant (p=0.007, p=0.004, respectively). Differential PCR was also performed to detect amplification of the cyclin D1 gene and mutational analysis was undertaken for exon 3 of the β-catenin gene. Amplification of the cyclin D1 gene was observed in 13 out of 22 cases (59.1%). There were nine-point mutations in 7 out of 18 cases (38.9%). The distribution of β-catenin mutation fell within a wide range, from codon 21 to codon 67. In conclusion, β-catenin nuclear expression correlated with cyclin D1 overexpression in sporadic desmoid tumours, which could be an in vivo model system for the APC-β-catenin-Tcf pathway. In addition, β-catenin mutations in desmoid tumours occurred at an unusually wide range of sites within the gene. Copyright © 2001 John Wiley & Sons, Ltd.

Abstract.: We report on a case of primary leiomyosarcoma of the patella in a 59-year-old woman. To our knowledge, this is the first report of this rare tumor in a bone where malignant lesions rarely occur.

The Arabidopsis chy1 mutant is resistant to indole-3-butyric acid, a naturally occurring form of the plant hormone auxin. Because the mutant also has defects in peroxisomal beta-oxidation, this resistance presumably results from a reduced conversion of indole-3-butyric acid to indole-3-acetic acid. We have cloned CHY1, which appears to encode a peroxisomal protein 43% identical to a mammalian valine catabolic enzyme that hydrolyzes beta-hydroxyisobutyryl-CoA. We demonstrated that a human beta-hydroxyisobutyryl-CoA hydrolase functionally complements chy1 when redirected from the mitochondria to the peroxisomes. We expressed CHY1 as a glutathione S-transferase (GST) fusion protein and demonstrated that purified GST-CHY1 hydrolyzes beta-hydroxyisobutyryl-CoA. Mutagenesis studies showed that a glutamate that is catalytically essential in homologous enoyl-CoA hydratases was also essential in CHY1. Mutating a residue that is differentially conserved between hydrolases and hydratases established that this position is relevant to the catalytic distinction between the enzyme classes. It is likely that CHY1 acts in peroxisomal valine catabolism and that accumulation of a toxic intermediate, methacrylyl-CoA, causes the altered beta-oxidation phenotypes of the chy1 mutant. Our results support the hypothesis that the energy-intensive sequence unique to valine catabolism, where an intermediate CoA ester is hydrolyzed and a new CoA ester is formed two steps later, avoids methacrylyl-CoA accumulation.

Animals, fungi, and some protozoa convert oxidosqualene to lanosterol in the ring-forming reaction in sterol biosynthesis. The Trypanosoma cruzi lanosterol synthase has now been cloned. The sequence shares with the T. brucei lanosterol synthase a tyrosine substitution for the catalytically important active-site threonine found in animal and fungal lanosterol synthases.

A new method to measure heat flux and thermal expansion simultaneously with a temperature resolution of milli-Kelvin is presented to observe the multistage transitions. At least six thermal anomalies are observed between 402 and 403 K in BaTiO3simultaneously in heat flux and thermal expansion in the cooling process. The correspondence of the anomalies observed in the two physical properties is excellent.