Search

Multifilamentary MgB2 strands (filament numbers 36 to 114) prepared by the in-situ power-in-tube (PIT) route with carbon doping contents of 0, 2, and 3.2% were wound on barrels for transport Jc and n-value measurement at 4.2 K in fields of up to 12 T. The strand and gauge lengths were 1 m and 0.5 m. Heat treatments at 675 °C and 650 °C centered around the melting point of Mg (650 °C) and both utilized the liquid-solid reaction. A pair of strands, with and without 2% C doping exhibited the Jc (B) crossover effect. Studied were the dependencies of Jc on field strength, dopant concentration, and cabling and the dependence of n-value on field strength.

Occup Environ Med 2003;60:876-881 Aims: To investigate the association between air pollution, including with N[O.sub.2], and recurrent wheezing during the first two years of life. Methods: A birth cohort (BAMSE) [...]

Long‐lasting (> 20 h) electromagnetic ion cyclotron (EMIC) Pc1‐Pc2 waves were observed by the Athabasca (L=∼ 4.6) induction magnetometer and Canadian Array for Realtime Investigations of Magnetic Activity (L=∼ 4–6) fluxgate magnetometers on 5 April 2007. These waves showed a systematic frequency change with local time, the minimum frequency near dusk, and the maximum frequency near dawn. Assuming the plasmapause as a potential source region of the waves, we estimated the plasmapause location from localized proton enhancement (LPE) events observed at NOAA‐Polar Orbiting Environmental Satellites and METOP‐2 satellites. We found that the longitudinal frequency variation of EMIC waves has a clear correlation with the estimated plasmapause location and that the waves are in the frequency band between the equatorial helium and oxygen gyrofrequencies at the estimated plasmapause. With our analysis results we suggest that the LPE events are caused by wave‐particle interaction with the helium band EMIC waves generated near the plasmapause. Long‐lasting (> 20 h) EMIC waves are detected by ground‐based magnetometer (near L∼ 4–6)These EMIC waves have a systematic frequency change with local timeThe local time frequency variation has a clear correlation with the estimated plasmapause location

We statistically examined the plasmapause location (Lpp) under quiet geomagnetic conditions (Kp≤ 1) using the electron density inferred from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft potential for 2 year period (2008 and 2009). Five hundred forty‐three Lppsamples were identified under steady quiet conditions with Kpvalues ≤ 1 during 12 h prior to the plasmapause crossing. From our large data set, we determined the medians and means of Lppin Land magnetic local time (MLT). They are located near geosynchronous orbit and nearly circular. The Lppmedians show a slight bulge located in postdusk sector. Comparing with previous models, our median or mean Lppis extended ∼1–2 Lfrom the Earth than the model Lppalong the local time from 0800 to 2400 MLT. That is, Lpplocations in the previous models are underestimated during quiet geomagnetic conditions. Plasmapause locations under quiet geomagnetic conditionsPlasmaspheric bulge in the dusk sectorQuiet time plasmapause extended toward geosynchronous orbit

Plasmaspheric virtual resonance (PVR) model has been proposed as one of source mechanisms for low‐latitude Pi2 pulsations. Since PVR‐associated Pi2 pulsations are not localized inside the plasmasphere, simultaneous multipoint observations inside and outside the plasmasphere require to test the PVR model. Until now, however, there are few studies using simultaneous multisatellite observations inside and outside the plasmasphere for understanding the radial structure of Pi2 pulsation. In this study, we focus on the Pi2 event observed at low‐latitude Bohyun (BOH, L= 1.35) ground station in South Korea in the postmidnight sector (magnetic local time (MLT) = 3.0) for the interval from 1730 to 1900 UT on 12 March 2013. By using electron density derived from the frequency of the upper hybrid waves detected at Van Allen Probe‐A (VAP‐A) and Van Allen Probe‐B (VAP‐B), the plasmapause is identified. At the time of the Pi2 event, VAP‐A was outside the plasmasphere near midnight (00:55 MLT and L=∼ 6), while VAP‐B was inside the plasmasphere in the postmidnight sector (02:15 MLT and L=∼ 5). VAP‐B observed oscillations in the compressional magnetic field component (Bz) and the dawn‐to‐dusk electric field component (Ey), having high coherence with the BOH Pi2 pulsation in the Hcomponent. The H‐Bzand H‐Eycross phases at VAP‐B inside the plasmasphere were near −180° and −90°, respectively. These phase relationships among Bz, Ey, and Hare consistent with a radially standing oscillation of the fundamental mode reported in previous studies. At VAP‐A outside the plasmasphere, Bzoscillations were highly correlated with BOH Pi2 pulsations with ∼−180° phase delay, and the H‐Eycross phase is near −90°. From these two‐satellite observations, we suggest that the fundamental PVR mode is directly detected by VAP‐A and VAP‐B. Multipoint observations of Pi2 pulsations in spacePlasmaspheric virtual resonances for Pi2 pulsationsRadial mode structure of Pi2 pulsation

When an interplanetary (IP) shock passes over the Earth's magnetosphere, the geosynchronous magnetic field strength near noon is always enhanced except for the magnetopause crossing events. Near midnight, however, it increases or decreases. This indicates that the nightside magnetosphere is not always compressed by a sudden increase in the solar wind dynamic pressure. To understand midnight geosynchronous magnetic field responses to IP shocks, we statistically examined geosynchronous magnetic field perturbations, corresponding to 120 sudden commencements (SCs), observed when geosynchronous spacecraft were near midnight between 2200 and 0200 magnetic local times. Out of the 120 SCs, 107 SCs were identified by one geosynchronous spacecraft, and 13 SCs were identified by two geosynchronous spacecraft. Thus, 133 events were used in our statistical study. We observed 23 events in spring, 40 events in summer, 32 events in fall, and 38 events in winter, respectively. A statistical study of the midnight geosynchronous SC perturbations reveals the following characteristics. (1) In summer, all events show a positive enhancement (+ΔBT) in the magnetic field strength. (2) In winter, however, ΔBTexhibits a positive (+ΔBT) or negative (–ΔBT) enhancement. (3) In summer, the midnight geosynchronous SC perturbations in the BHcomponent (positive northward) in VDH coordinates are mostly (∼88%, 35 out of 40 events) positive (+ΔBH), while the occurrence rate of the positive perturbation (∼43%) in the Bzcomponent (positive northward) in GSM coordinates is lower than that of the negative perturbation (∼57%). (4) In winter, the negative perturbations in ΔBH(∼61%) and ΔBz(∼74%) are dominant. (5) Both the north‐south components (BHand Bz) in spring and fall are scattered around zero. To explain the observations, we suggest that SC‐associated cross‐tail current (JSC) has a peak intensity around geosynchronous orbit and thus is a main controlling factor of midnight geosynchronous magnetic field perturbations during SCs. Specifically, we suggest that the seasonal variation of the sign of ΔBH, ΔBz, and ΔBTis due to the seasonal variation of the spacecraft position relative to JSC. Midnight SC‐associated B field perturbationsSeasonal variations of SC‐associated geosynchronous B perturbationsSC‐associated cross‐tail current near geosynchronous orbit

Direct carotid-cavernous fistula (CCF) by selective navigation using a microcatheter or microwire is a rare complication, and its timing of treatment has not been elucidated. We report two cases of direct CCFs resulting from injury to the cavernous posterior segment of the internal carotid artery during selective navigation. We did not plan to perform emergent endovascular treatment for these direct CCFs because no symptoms related to direct CCFs developed. Follow-up angiography revealed spontaneous healing of both direct CCFs. Close observation rather than emergent treatment may represent another option for direct CCF by selective navigation during the endovascular procedure.

Sigmoid sinus diverticulum, a rare dural sinus anomaly, is regarded as one of the very rare causes of pulsatile tinnitus, and there have been only a few reports on their surgical or endovascular management. We describe a 31-year-old woman presenting with a three-year pulsatile tinnitus in her right ear. After finding the small bony defect in her right temporal bone on CT which was filled with contrast after enhancement, we confirmed the presence of sigmoid sinus diverticulum with the cerebral angiogram and embolized it with two detachable coils in awake status. Right after filling the two coils into the sac, thanks to her alert consciousness, she was able to refer the disappearance of her tinnitus. The operation was finished only with the detachment of the coils.

A 5-year-old, female, Japanese Macaque (Macaca fuscata) was diagnosed with round cell variant of myxoid liposarcoma. At necropsy, multifocal to coalescing, reddish tan to white nodules, ranging from 0.5 to 1 cm in diameter, were noted throughout the omentum and retroperitoneum. Similar neoplastic nodules were also present in diaphragm, abdominal wall, and on hepatic capsule. Microscopically, neoplastic masses consisted of round to polyhedral cells, which had round, often eccentric nuclei and abundant eosinophilic granular and microvacuolated cytoplasm; Oil red O staining demonstrated large numbers of lipid droplets in the cytoplasm. Ultrastructurally, the cytoplasm of the tumor cells was packed with occasional lipid vacuoles and numerous enlarged mitochondria. Immunohistochemistry revealed tumor cells were positive for vimentin, while negative to cytokeratin, actin, and Factor VIII-related antigen. To the authors' knowledge, this is the first report of round-cell variant of myxoid liposarcoma in nonhuman primate.

F-actins are semi-flexible polyelectrolytes and can be assembled into a large polymer-actin complex with polymorphism through electrostatic interaction with polycations. This study investigates the structural phase behavior and the growth of polymer−actin complexes in terms of its longitudinal and lateral sizes in various polycation and KCl concentrations for a constant actin concentration. Our results show that the longitudinal growth and lateral growth of polymer−actin complexes, initiated by a common nucleation process, are dominated by different factors in subsequent growth process. This induces the structural polymorphism of polymer−actin complexes. Major factors to influence the polymorphism of polymer−actin complexes in polyelectrolyte systems have been discussed. Our results indicate that the semiflexible polyelectrolyte nature of F-actins is important for controlling the morphology and growth of actin architectures in cells.

In studying biological roles of interferon regulatory factor (IRF)-1 tumor suppressor in cervical carcinogenesis, we found that HPV E7 is functionally associated with IRF-1. Binding assays indicate a physical interaction between IRF-1 and HPV E7 in vivo and in vitro. The carboxyl-terminal transactivation domain of IRF-1 was required for the interaction. Transient co-expression of E7 significantly inhibits the IRF-1-mediated activation of IFN-beta promoter in NIH-3T3 cells. Co-transfection of E7 mutants reveals that the pRb-binding portion of E7 is necessary for the E7-mediated inactivation of IRF-1. It was next determined whether histone deacetylase (HDAC) is involved in the inactivation mechanism as recently suggested, where the carboxyl-terminal zinc finger domain of E7 associates with NURD complex containing HDAC. When trichostatin A, an inhibitor of HDAC, was treated, the repressing activity of E7 was released in a dose-dependent manner. Furthermore, the mutation of zinc finger abrogates such activity without effect on the interaction with IRF-1. These results suggest that HPV E7 interferes with the transactivation function of IRF-1 by recruiting HDAC to the promoter. The immune-promoting role of IRF-1 evokes the idea that our novel finding might be important for the elucidation of the E7-mediated immune evading mechanism that is frequently found in cervical cancer.

An amino group has been appended to a benzoquinolinato ligand (bq-NH2 or bq-NH(i-Pr)) in such a way that it can hydrogen bond to a ligand that is also bound to the metal. The effects of this two-point binding are studied. The complexes [(bq-NHR)IrH(L)(PPh3)2]BF4 (R = H, i-Pr) were synthesized where L = H2O, F. The hydrogen-bonding pattern in the water complex is probed by crystallographic, IR, and NMR studies. The fluoro complexes protonate at −90 °C to give unstable hydrogen fluoride complexes, characterized by NMR (¹JHF = 440 Hz, bq-NH2; 430 Hz, bq-NH(i-Pr)). Comparison with results for the corresponding bq-H and bq-CH3 species suggests that the hydrogen bonding provided by the pendant amino group is the key factor that allows stabilization of the HF complex, a previously unknown species. Crystal structures of an aqua and a fluoro derivative are reported.

Transcriptional repression by sequence-specific DNA binding factors is mediated by the recruitment of a corepressor complex to the promoter region. The NK-3 homeodomain protein is a transcriptional repressor that recruits the nuclear protein kinase, homeodomain interacting protein kinase 2 (HIPK2). Here we show that HIPK2 is a component of a corepressor complex containing Groucho and a histone deacetylase complex. Groucho, like HIPK2, acts as a corepressor for NK-3 and binds to NK-3 and HIPK2. Moreover, HIPK2 appears to regulate the corepressor activity of Groucho. Transcriptional repression by NK-3 and Groucho is relieved by the histone deacetylase inhibitor trichostatin A, and both NK-3 and Groucho directly interact with the histone deacetylase HDAC1 that is associated with mSin3A in vivo. Recruitment of the histone deacetylase complex by NK-3 decreases the acetylated histones that are associated with the target gene promoter. These results indicate that NK-3 represses transcription by recruiting a complex containing Groucho and a histone deacetylase complex that leads to histone modification on chromatin and suggest that HIPK2 may play a regulatory role in the corepressor complex formation.

Alignments of 105 site-specific recombinases belonging to the Int family of proteins identified extended areas of similarity and three types of structural differences. In addition to the previously recognized conservation of the tetrad R-H-R-Y, located in boxes I and II, several newly identified sequence patches include charged amino acids that are highly conserved and a specific pattern of buried residues contributing to the overall protein fold. With some notable exceptions, unconserved regions correspond to loops in the crystal structures of the catalytic domains of lambda Int (Int c170) and HP1 Int (HPC) and of the recombinases XerD and Cre. Two structured regions also harbor some pronounced differences. The first comprises beta-sheets 4 and 5, alpha-helix D and the adjacent loop connecting it to alpha-helix E: two Ints of phages infecting thermophilic bacteria are missing this region altogether; the crystal structures of HPC, XerD and Cre reveal a lack of beta-sheets 4 and 5; Cre displays two additional beta-sheets following alpha-helix D; five recombinases carry large insertions. The second involves the catalytic tyrosine and is seen in a comparison of the four crystal structures. The yeast recombinases can theoretically be fitted to the Int fold, but the overall differences, involving changes in spacing as well as in motif structure, are more substantial than seen in most other proteins. The phenotypes of mutations compiled from several proteins are correlated with the available structural information and structure-function relationships are discussed. In addition, a few prokaryotic and eukaryotic enzymes with partial homology with the Int family of recombinases may be distantly related, either through divergent or convergent evolution. These include a restriction enzyme and a subgroup of eukaryotic RNA helicases (D-E-A-D proteins).

Two isoforms of cyclooxygenase (COX) have been identified in eukaryotic cells: a constitutively expressed COX-1 and mitogen-inducible COX-2, which is selectively expressed in response to various inflammatory stimuli. Thus, COX-2 instead of COX-1 is implicated to produce prostanoids mediating inflammatory responses. Major efforts have been focused on identifying nonsteroidal anti-inflammatory drugs (NSAIDS) which can selectively inhibit the enzyme activity of COX-2. Such NSAIDS would be more desirable anti-inflammatory agents in comparison to NSAIDS which inhibit both COX-1 and COX-2. Other than glucocorticoids, pharmacological agents which can selectively suppress the expression of COX-2 without affecting that of COX-1 have not been identified. We report here that radicicol, a fungal antibiotic, is a potent protein tyrosine kinase inhibitor, and that it inhibits the expression of COX-2 without affecting COX-1 expression in lipopolysaccharide (LPS)-stimulated macrophages with the IC50 value of 27 nM. Radicicol inhibited tyrosine phosphorylation of p53/56lyn, a Src family tyrosine kinase and one of the major tyrosine-phosphorylated proteins in LPS-stimulated macrophages. Radicicol also inhibited COX-2 expression in vivo in glomeruli of rats with experimental glomerulonephritis induced by the anti-glomerular basement membrane antibodies, in which COX-2 expression is known to be enhanced. The enzyme activity of COX-1 or COX-2 was not affected by radicicol in macrophages. Radiciciol also suppressed the COX-2 expression induced by IL-1 beta in rat smooth muscle cells. Other protein tyrosine kinase inhibitors suppressed the LPS-induced COX-2 expression in macrophages but at much higher concentrations than needed for radicicol. Radicicol did not inhibit the COX-2 expression induced by phorbol 12-myristate 13-acetate in macrophages. These results suggest that the activation of tyrosine-specific protein kinases is the proximal obligatory step in the LPS-induced signal transduction pathway leading to the induction of COX-2 expression in macrophages. The magnitude of the inhibition of COX-2 protein synthesis by radicicol was much greater than that of the steady state levels of COX-2 mRNA. These results suggest that radicicol inhibits COX-2 expression mainly at post-transcriptional steps.

Abstract: Streptomyces clavuligerus produces a clinically important β-lactamase inhibitor, clavulanic acid. When several of the selected redox-cycling agents were treated, an increase in clavulanate production was observed. The stimulatory effect was seen when the reaction was fed with menadione, plumbagin and phenazine methosulfate (PMS), whereas feeding with methyl viologen had a negative effect. PMS exerted the strongest effect, enhancing the accumulation of clavulanic acid by 150%. Induction of superoxide dismutase upon the addition of PMS suggested an involvement of superoxide in the enhancing process. The stimulatory effect of PMS was offset by the addition of butylated hydroxyanisole, further supporting the involvement of the active oxygen. The enhanced production of clavulanic acid correlated well with the increased total activity of clavaminic acid synthase, a key enzyme in its biosynthesis, and the transcription of cas2, its coding gene. The results suggested that active oxygen species could enhance the biosynthesis of secondary metabolites through the transcriptional activation of the biosynthetic gene.

Expression of a novel thymocyte differentiation antigen, JL1, defined by a monoclonal antibody (mAb) developed against human thymocytes showed a specificity for stage II double positive (CD4+CD8+) human cortical thymocytes. This antigen was not expressed at detectable levels on medullary thymocytes, mature peripheral leukocytes, bone marrow cells or on other types of tissues elsewhere in the human body. Immunohistologic analysis revealed that JL1 had a clear pattern of distribution on cortical thymocytes. Immunoprecipitation of 125I-labeled cell lysates from human thymocytes and Molt-4 leukemic cell line with anti-JL1 mAb yielded a 120-130-kD single chain glycoprotein. When immunoprecipitation of cell lysate was done after endoglycosidase F treatment, JL1 antigen was still detected by antibody but the band showed a reduction in apparent molecular mass of approximately 5 kD. This suggests that, although JL1 molecule contains carbohydrate group, this does not form a critical part of the antigenic determinant for anti-JL1 antibody. JL1 antigen appears to be the first double positive, stage-specific differentiation antigen of human thymocyte reported so far. This antigen would be a useful marker for lymphoblastic malignancy of stage II thymocyte origin and it may be involved in the thymocyte education process.

We examine magnetic and electric field perturbations associated with a sudden commencement (SC), caused by an interplanetary (IP) shock passing over the Earth's magnetosphere on 16 February 2013. The SC was identified in the magnetic and electric field data measured at Time History of Events and Macroscale Interactions during Substorms (THEMIS‐E; THE‐E: magnetic local time (MLT) = 12.4, L= 6.3), Van Allen Probe‐A (VAP‐A: MLT = 3.2, L= 5.1), and Van Allen Probe‐B (VAP‐B: MLT = 0.2. L= 4.9) in the magnetosphere. During the SC interval, THE‐E observed a dawnward‐then‐duskward electric (E) field perturbation around noon, while VAP‐B observed a duskward Efield perturbation around midnight. VAP‐A observed a dawnward‐then‐duskward Efield perturbation in the postmidnight sector, but the duration and magnitude of the dawnward Eperturbation are much shorter and weaker than that at THE‐E. That is, the Efield signature changes with local time during the SC interval. The Super Dual Auroral Radar Network radar data indicate that the ionospheric plasma motions during the SC are mainly due to the Efield variations observed in space. This indicates that the SC‐associated Efield in space plays a significant role in determining the dynamic variations of the ionospheric convection flow. By comparing previous SC MHD simulations and our observations, we suggest that the Efield variations observed at the spacecraft are produced by magnetospheric convection flows due to deformation of the magnetosphere as the IP shock sweeps the magnetopause. SC‐associated Efield signature changes with local time during SC intervalThe Efield variation is associated with magnetospheric convection flow enhanced during SC intervalIonospheric convection flow is strongly connected with SC‐associated Efield variation

We consider a one-dimensional superconducting wire where the total number of electrons can be controlled in the Coulomb blockade regime. We predict that a pi-soliton (kink) will spontaneously form in the system when the number of electron is odd, because this configuration has a lower energy. If the wire with an odd number of electrons is closed in a ring, the phase difference on the two sides of the soliton will generate a supercurrent detectable by SQUID.  The  two  degenerate  states  with  the current  flowing  clockwise  or counterclockwise  can  be  utilized  as  a  qbit. The paper is available at:http://publish.aps.org/abstract/PRL/v89/p17002Phys. Rev. Lett. 89, 017002 (2002) H.-J. Kwon and V.M. Yakovenko “Spontaneous formation of a pi Soliton in a Number of Electrons"

This study aims to evaluate whether prenatal psychological stress associated with preterm birth and low birth weight through increase of maternal serum cortisol level.

Several cross-sectional studies have shown higher prevalence of respiratory disorders in children exposed to environmental risk factors. This preliminary study was designed to examine the respiratory symptoms of children exposed to various environmental factors.

The Korean peninsula has a long history of spring time dust clouds blown by winds from the arid deserts of Mongolia and China, these are called Asian dust event. During the episode in 2002, daily average of PM10 in Seoul exceeded 600 mg/m3. Public concern about the possible adverse effects of these dust events has increased, because the dust arrives in Korea after having passed over heavily industrialized eastern China. This study was planned to investigate the association between the episode of the Asian dust and hospital admissions with respiratory and cardiovascular disease in Seoul, Korea. We constructed daily counts of all admissions for respiratory disease (ICD-10 codes J00–J99) and cardiovascular disease (ICD-10 codes I00–I99) in Seoul during the period of 2000 through 2002. A generalized linear model with a log-link and a Poisson distribution were used to examine the relation of Asian dust events to hospital admissions, adjusting for weather variables and time trends of admission counts. To accommodate delayed effects of Asian dust events, we fitted the model with 7-day moving averages of admission counts. The estimated relative risk of hospitalization for respiratory disease for the Asian dust events was 1.00 (95 confidence interval [CI] = 0.96–1.03) and the risk for cardiovascular disease was 0.99 (95 CI = 0.96–1.02). Our results indicate that the Asian dust events experienced in Seoul has little effect on the hospitalization for respiratory and cardiovascular disease in general. Acknowledgement: this study was supported by the Ministry of Environment, Republic of Korea (Eco-technopia 2002).