29 research outputs found
Optical and Near-Infrared Photometry of Nova V2362 Cyg : Rebrightening Event and Dust Formation
We present optical and near-infrared (NIR) photometry of a classical nova,
V2362 Cyg (= Nova Cygni 2006). V2362 Cyg experienced a peculiar rebrightening
with a long duration from 100 to 240 d after the maximum of the nova. Our
multicolor observation indicates an emergence of a pseudophotosphere with an
effective temperature of 9000 K at the rebrightening maximum. After the
rebrightening maximum, the object showed a slow fading homogeneously in all of
the used bands for one week. This implies that the fading just after the
rebrightening maximum ( less or equal 1 week ) was caused by a slowly shrinking
pseudophotosphere. Then, the NIR flux drastically increased, while the optical
flux steeply declined. The optical and NIR flux was consistent with blackbody
radiation with a temperature of 1500 K during this NIR rising phase. These
facts are likely to be explained by dust formation in the nova ejecta. Assuming
an optically thin case, we estimate the dust mass of 10^(-8) -- 10^(-10)
M_solar, which is less than those in typical dust-forming novae. These results
support the senario that a second, long-lasting outflow, which caused the
rebrightening, interacted with a fraction of the initial outflow and formed
dust grains.Comment: 6 pages, 4 figures, 2010, PASJ, 62, 1103--1108, in pres
The 2006 November outburst of EG Aquarii: the SU UMa nature revealed
We report time-resolved CCD photometry of the cataclysmic variable EG Aquarii
during the 2006 November outburst During the outburst, superhumps were
unambiguously detected with a mean period of 0.078828(6) days, firstly
classifying the object as an SU UMa-type dwarf nova. It also turned out that
the outburst contained a precursor. At the end of the precursor, immature
profiles of humps were observed. By a phase analysis of these humps, we
interpreted the features as superhumps. This is the second example that the
superhumps were shown during a precursor. Near the maximum stage of the
outburst, we discovered an abrupt shift of the superhump period by
0.002 days. After the supermaximum, the superhump period decreased at the rate
of =, which is typical for SU UMa-type dwarf
novae. Although the outburst light curve was characteristic of SU UMa-type
dwarf novae, long-term monitoring of the variable shows no outbursts over the
past decade. We note on the basic properties of long period and inactive SU
UMa-type dwarf novae.Comment: 9 pages, 7 figures, accepted for PAS
Feasibility study of immediate pharyngeal cooling initiation in cardiac arrest patients after arrival at the emergency room
AIM:
Cooling the pharynx and upper oesophagus would be more advantageous for rapid induction of therapeutic hypothermia since the carotid arteries run in their vicinity. The aim of this study was to determine the effects of pharyngeal cooling on brain temperature and the safety and feasibility for patients under resuscitation.
METHODS:
Witnessed non-traumatic cardiac arrest patients (n=108) were randomized to receive standard care with (n=53) or without pharyngeal cooling (n=55). In the emergency room, pharyngeal cooling was initiated before or shortly after return of spontaneous circulation by perfusing physiological saline (5 °C) into a pharyngeal cuff for 120 min.
RESULTS:
There was a significant decrease in tympanic temperature at 40 min after arrival (P=0.02) with a maximum difference between the groups at 120 min (32.9 ± 1.2°C, pharyngeal cooling group vs. 34.1 ± 1.3°C, control group; P<0.001). The return of spontaneous circulation (70% vs. 65%, P=0.63) and rearrest (38% vs. 47%, P=0.45) rates were not significantly different based on the initiation of pharyngeal cooling. No post-treatment mechanical or cold-related injury was observed on the pharyngeal epithelium by macroscopic observation. The thrombocytopaenia incidence was lower in the pharyngeal cooling group (P=0.001) during the 3-day period after arrival. The cumulative survival rate at 1 month was not significantly different between the two groups.
CONCLUSIONS:
Initiation of pharyngeal cooling before or immediately after the return of spontaneous circulation is safe and feasible. Pharyngeal cooling can rapidly decrease tympanic temperature without adverse effects on circulation or the pharyngeal epithelium
Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo
Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level
Ultralight vector dark matter search using data from the KAGRA O3GK run
Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM
Naphthodithiophenediimide–Benzobisthiadiazole-Based Polymers: Versatile n‑Type Materials for Field-Effect Transistors and Thermoelectric Devices
New
π-conjugated polymers with strong electron affinity,
PNDTI-BBTs, consisting of naphtho[2,3-<i>b</i>:6,7-<i>b</i>′]dithiophenediimide (NDTI) and benzo[1,2-<i>c</i>:4,5-<i>c</i>′]bis[1,2,5]thiadiazole
(BBT) units, were synthesized. PNDTI-BBTs have low-lying LUMO energy
levels (∼−4.4 eV), which is sufficiently low for air-stable
electron transport in organic field-effect transistors and for being
readily doped by a well-known n-dopant, <i>N</i>,<i>N</i>-dimethyl-2-phenyl-2,3-dihydro-1<i>H</i>-benzoimidazole
(<i>N</i>-DMBI), affording doped polymer films with relatively
high conductivities and Seebeck coefficients. Depending on the solubilizing
alkyl groups (2-decyltetradecyl, PNDTI-BBT-DT, or 3-decylpentadecyl
groups, PNDTI-BBT-DP), not only the electron mobility in the transistor
devices with the pristine polymer thin films (PNDTI-BBT-DT: ∼0.096
cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>; PNDTI-BBT-DP:
∼0.31 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>) but also the conductivity and power factor of the doped thins films
(PNDTI-BBT-DT: ∼0.18 S cm<sup>–1</sup> and ∼0.6
μW m<sup>–1</sup> K<sup>–2</sup>; PNDTI-BBT-DP:
∼5.0 S cm<sup>–1</sup> and ∼14 μW m<sup>–1</sup> K<sup>–2</sup>) were drastically changed.
The differences in the electric properties were primarily ascribed
to the better crystalline nature of the PNDTI-BBT-DP than those of
PNDTI-BBT-DT in the thin-film state. Furthermore, UV–vis and
ESR spectra demonstrated that doping effectiveness was largely affected
by the alkyl groups: the PNDTI-BBT-DP films with better crystalline
order prevented overdoping, resulting in ca. 20 times higher conductivity
and power factors. From these results, it can be concluded that tuning
the intermolecular interaction and consequently obtaining the thin-film
with well-ordered polymers by the alkyl side chains is a promising
strategy for developing superior thermoelectric materials
Gene Expression Profile Signature of Aggressive Waldenström Macroglobulinemia with Chromosome 6q Deletion
Background. Waldenström macroglobulinemia (WM) is a rare, indolent B-cell lymphoma. Clinically, chromosome 6q deletion (6q del) including loss of the B lymphocyte-induced maturation protein 1 gene (BLIMP-1) is reported to be associated with poor prognosis. However, it remains unclear how the underlying biological mechanism contributes to the aggressiveness of WM with 6q del. Methods. Here, we conducted oligonucleotide microarray analysis to clarify the differences in gene expression between WM with and without 6q del. Gene ontology (GO) analysis was performed to identify the main pathways underlying differences in gene expression. Eight bone marrow formalin-fixed paraffin-embedded samples of WM were processed for interphase fluorescence in situ hybridization analysis, and three were shown to have 6q del. Results. GO analysis revealed significant terms including “lymphocyte activation” (corrected p value=6.68E-11), which included 31 probes. Moreover, IL21R and JAK3 expression upregulation and activation of the B-cell receptor signaling (BCR) pathway including CD79a, SYK, BLNK, PLCγ2, and CARD11 were detected in WM with 6q del compared with WM without 6q del. Conclusion. The present study suggested that the BCR signaling pathway and IL21R expression are activated in WM with 6q del. Moreover, FOXP1 and CBLB appear to act as positive regulators of the BCR signaling pathway. These findings might be attributed to the aggressiveness of the WM with 6q del expression signature
Oxygen-radical pretreatment promotes cellulose degradation by cellulolytic enzymes
Abstract Background The efficiency of cellulolytic enzymes is important in industrial biorefinery processes, including biofuel production. Chemical methods, such as alkali pretreatment, have been extensively studied and demonstrated as effective for breaking recalcitrant lignocellulose structures. However, these methods have a detrimental effect on the environment. In addition, utilization of these chemicals requires alkali- or acid-resistant equipment and a neutralization step. Results Here, a radical generator based on non-thermal atmospheric pressure plasma technology was developed and tested to determine whether oxygen-radical pretreatment enhances cellulolytic activity. Our results showed that the viscosity of carboxymethyl cellulose (CMC) solutions was reduced in a time-dependent manner by oxygen-radical pretreatment using the radical generator. Compared with non-pretreated CMC, oxygen-radical pretreatment of CMC significantly increased the production of reducing sugars in culture supernatant containing various cellulases from Phanerochaete chrysosporium. The production of reducing sugar from oxygen-radical-pretreated CMC by commercially available cellobiohydrolases I and II was 1.7- and 1.6-fold higher, respectively, than those from non-pretreated and oxygen-gas-pretreated CMC. Moreover, the amount of reducing sugar from oxygen-radical-pretreated wheat straw was 1.8-fold larger than those from non-pretreated and oxygen-gas-pretreated wheat straw. Conclusions Oxygen-radical pretreatment of CMC and wheat straw enhanced the degradation of cellulose by reducing- and non-reducing-end cellulases in the supernatant of a culture of the white-rot fungus P. chrysosporium. These findings indicated that oxygen-radical pretreatment of plant biomass offers great promise for improvements in lignocellulose-deconstruction processes