Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
18,739
result(s) for
"WU, F."
Sort by:
Texas hold'em
\"San Antonio, home of the Alamo, is also host to the nation's top high school jazz competition, and the musicians at Xavier Desmond High are excited to outplay their rivals. They are also jokers, kids with strange abilities and even stranger looks. On top of that, well, they are teenagers, apt for mischief, mishaps, and romantic misunderstandings. Michelle Pond, aka The Amazing Bubbles, thinks that her superhero (and supermom) know-how has prepared her to chaperone the event. But when her students start going wayward, she'll soon discover the true meaning of 'Don't mess with Texas'\"--Dust jacket flap.
BOOK
Evidence for Weyl fermions in a canonical heavy-fermion semimetal YbPtBi
The manifestation of Weyl fermions in strongly correlated electron systems is of particular interest. We report evidence for Weyl fermions in the heavy fermion semimetal YbPtBi from electronic structure calculations, angle-resolved photoemission spectroscopy, magnetotransport and calorimetric measurements. At elevated temperatures where 4
f-
electrons are localized, there are triply degenerate points, yielding Weyl nodes in applied magnetic fields. These are revealed by a contribution from the chiral anomaly in the magnetotransport, which at low temperatures becomes negligible due to the influence of electronic correlations. Instead, Weyl fermions are inferred from the topological Hall effect, which provides evidence for a Berry curvature, and a cubic temperature dependence of the specific heat, as expected from the linear dispersion near the Weyl nodes. The results suggest that YbPtBi is a Weyl heavy fermion semimetal, where the Kondo interaction renormalizes the bands hosting Weyl points. These findings open up an opportunity to explore the interplay between topology and strong electronic correlations.
Weyl fermions are evidenced in weakly correlated electron systems, but whether they survive strong electron correlations remains obscure. Here, Guo et al. report evidence of the chiral anomaly, topological Hall effect and a cubic temperature dependence of specific heat, suggesting existence of Weyl fermions in a heavy fermion semimetal YbPtBi.
Journal Article
A magnetar-powered X-ray transient as the aftermath of a binary neutron-star merger
Mergers of neutron stars are known to be associated with short γ-ray bursts
1
–
4
. If the neutron-star equation of state is sufficiently stiff (that is, the pressure increases sharply as the density increases), at least some such mergers will leave behind a supramassive or even a stable neutron star that spins rapidly with a strong magnetic field
5
–
8
(that is, a magnetar). Such a magnetar signature may have been observed in the form of the X-ray plateau that follows up to half of observed short γ-ray bursts
9
,
10
. However, it has been expected that some X-ray transients powered by binary neutron-star mergers may not be associated with a short γ-ray burst
11
,
12
. A fast X-ray transient (CDF-S XT1) was recently found to be associated with a faint host galaxy, the redshift of which is unknown
13
. Its X-ray and host-galaxy properties allow several possible explanations including a short γ-ray burst seen off-axis, a low-luminosity γ-ray burst at high redshift, or a tidal disruption event involving an intermediate-mass black hole and a white dwarf
13
. Here we report a second X-ray transient, CDF-S XT2, that is associated with a galaxy at redshift
z
= 0.738 (ref.
14
). The measured light curve is fully consistent with the X-ray transient being powered by a millisecond magnetar. More intriguingly, CDF-S XT2 lies in the outskirts of its star-forming host galaxy with a moderate offset from the galaxy centre, as short γ-ray bursts often do
15
,
16
. The estimated event-rate density of similar X-ray transients, when corrected to the local value, is consistent with the event-rate density of binary neutron-star mergers that is robustly inferred from the detection of the gravitational-wave event GW170817.
Observations of an X-ray transient associated with a galaxy at redshift 0.738 suggest that the X-ray transient is powered by a millisecond magnetar and that it is the remnant of a merger between two neutron stars.
Journal Article
piRNA-823 contributes to tumorigenesis by regulating de novo DNA methylation and angiogenesis in multiple myeloma
Aberrant DNA hypermethylation contributes to myelomagenesis by silencing tumor-suppressor genes. Recently, a few reports have suggested that a novel class of small non-coding RNAs, called Piwi-interacting RNAs (piRNAs), may be involved in the epigenetic regulation of cancer. In this study, for the first time we provided evidence that the expression of piRNA-823 was upregulated in multiple myeloma (MM) patients and cell lines, and positively correlated with clinical stage. Silencing piRNA-823 in MM cells induced deregulation of cell cycle regulators and apoptosis-related proteins expression, accompanied by inhibition of tumorigenicity
in vitro
and
in vivo
. Moreover, piRNA-823 was directly relevant to
de novo
DNA methyltransferases, DNMT3A and 3B, in primary CD138
+
MM cells. The inhibited expression of piRNA-823 in MM cells resulted in marked reduction of DNMT3A and 3B at both mRNA and protein levels, which in turn led to decrease in global DNA methylation and reexpression of methylation-silenced tumor suppressor, p16
INK4A
. In addition, piRNA-823 abrogation in MM cells induced reduction of vascular endothelial growth factor secretion, with consequent decreased proangiogenic activity. Altogether, these data support an oncogenic role of piRNA-823 in the biology of MM, providing a rational for the development of piRNA-targeted therapeutic strategies in MM.
Journal Article
miR-21-mediated tumor growth
MicroRNAs (miRNAs) are ∼22 nucleotide non-coding RNA molecules that regulate gene expression post-transcriptionally. Although aberrant expression of miRNAs in various human cancers suggests a role for miRNAs in tumorigenesis, it remains largely unclear as to whether knockdown of a specific miRNA affects tumor growth. In this study, we profiled miRNA expression in matched normal breast tissue and breast tumor tissues by TaqMan real-time polymerase chain reaction miRNA array methods. Consistent with previous findings, we found that
miR-21
was highly overexpressed in breast tumors compared to the matched normal breast tissues among 157 human miRNAs analysed. To better evaluate the role of
miR-21
in tumorigenesis, we transfected breast cancer MCF-7 cells with anti-miR-21 oligonucleotides and found that anti-miR-21 suppressed both cell growth
in vitro
and tumor growth in the xenograft mouse model. Furthermore, this anti-miR-21-mediated cell growth inhibition was associated with increased apoptosis and decreased cell proliferation, which could be in part owing to downregulation of the antiapoptotic Bcl-2 in anti-miR-21-treated tumor cells. Together, these results suggest that
miR-21
functions as an oncogene and modulates tumorigenesis through regulation of genes such as
bcl-2
and thus, it may serve as a novel therapeutic target.
Journal Article
Impact of denosumab on cardiovascular calcification in patients with secondary hyperparathyroidism undergoing dialysis: a pilot study
SummaryThe receptor activator of nuclear factor-kappa B ligand (RANKL)/RANK/osteoprotegerin system is dysregulated in hyperparathyroid bone diseases. The introduction of denosumab preceding elective surgery as an alternative option when surgery is not possible immediately.IntroductionThe effects of denosumab on vascular calcification in patients with chronic renal failure and low bone mass have been a subject of interest. Therefore, this investigation aimed to determine the short-term changes in vascular calcification after denosumab treatment using a serial electrocardiography-gated computed tomography (CT) to measure coronary artery calcification (CAC) in patients with secondary hyperparathyroidism (SHPT) and low bone mass.MethodsThis 6-month study enrolled patients with SHPT and low bone mass (T-score < − 2.5) owing to dialysis. The 2 groups administered denosumab at a dose of 60 mg (denosumab group), and conventional treatment (control group) had 21 patients each. All patients underwent CT scans at baseline and at the follow-up examination at 6 months to determine the bone mineral density and CAC.ResultsThe control group demonstrated a significant increase in Agatston scores (187.79 ± 72.27) (P = 0.004). However, no significant change was noted in the denosumab group (P = 0.41). In the denosumab group, only the baseline serum alkaline phosphatase levels correlated negatively with changes in the CAC score (P = 0.01); the baseline alkaline phosphatase levels were the deciding biomarkers for non-responsive CAC scores by Berry Criteria after denosumab treatment (P = 0.02). The denosumab group demonstrated significantly increased bone mineral density in the femoral neck and lumbar spine (P < 0.01).ConclusionThe findings provide evidence that denosumab may suppress the progression of CAC and also regress osseous calcification in severe cases of high bone turnover.
Journal Article
EFFICIENT CALIBRATION FOR IMPERFECT COMPUTER MODELS
Many computer models contain unknown parameters which need to be estimated using physical observations. Tuo and Wu (2014) show that the calibration method based on Gaussian process models proposed by Kennedy and O'Hagan [J. R. Stat. Soc. Ser. B. Stat. Methodol. 63 (2001) 425-464] may lead to an unreasonable estimate for imperfect computer models. In this work, we extend their study to calibration problems with stochastic physical data. We propose a novel method, called the L₂ calibration, and show its semiparametric efficiency. The conventional method of the ordinary least squares is also studied. Theoretical analysis shows that it is consistent but not efficient. Numerical examples show that the proposed method outperforms the existing ones.
Journal Article
A peculiar low-luminosity short gamma-ray burst from a double neutron star merger progenitor
Double neutron star (DNS) merger events are promising candidates of short gamma-ray burst (sGRB) progenitors as well as high-frequency gravitational wave (GW) emitters. On August 17, 2017, such a coinciding event was detected by both the LIGO-Virgo gravitational wave detector network as GW170817 and Gamma-Ray Monitor on board NASA’s
Fermi
Space Telescope as GRB 170817A. Here, we show that the fluence and spectral peak energy of this sGRB fall into the lower portion of the distributions of known sGRBs. Its peak isotropic luminosity is abnormally low. The estimated event rate density above this luminosity is at least
19
0
-
160
+
440
Gpc
−3
yr
−1
, which is close to but still below the DNS merger event rate density. This event likely originates from a structured jet viewed from a large viewing angle. There are similar faint soft GRBs in the
Fermi
archival data, a small fraction of which might belong to this new population of nearby, low-luminosity sGRBs.
A short-duration gamma-ray burst was detected along with a double neutron start merger gravitational wave by LIGO-Virgo on August 17th 2017. Here, the authors show that the fluence and spectral peak energy of this event fall into the lower portion of the distribution of known short-duration gamma-ray bursts.
Journal Article
Double-cone ignition scheme for inertial confinement fusion
While major progress has been made in the research of inertial confinement fusion, significant challenges remain in the pursuit of ignition. To tackle the challenges, we propose a double-cone ignition (DCI) scheme, in which two head-on gold cones are used to confine deuterium–tritium (DT) shells imploded by high-power laser pulses. The scheme is composed of four progressive controllable processes: quasi-isentropic compression, acceleration, head-on collision and fast heating of the compressed fuel. The quasi-isentropic compression is performed inside two head-on cones. At the later stage of the compression, the DT shells in the cones are accelerated to forward velocities of hundreds of km s –1 . The head-on collision of the compressed and accelerated fuels from the cone tips transfer the forward kinetic energy to the thermal energy of the colliding fuel with an increased density. The preheated high-density fuel can keep its status for a period of approximately 200 ps. Within this period, MeV electrons generated by ps heating laser pulses, guided by a ns laser-produced strong magnetic field further heat the fuel efficiently. Our simulations show that the implosion inside the head-on cones can greatly mitigate the energy requirement for compression; the collision can preheat the compressed fuel of approximately 300 g cm −3 to a temperature above keV. The fuel can then reach an ignition temperature of greater than 5 keV with magnetically assisted heating of MeV electrons generated by the heating laser pulses. Experimental campaigns to demonstrate the scheme have already begun. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 1)’.
Journal Article
Membrane Tension Acts Through PLD2 and mTORC2 to Limit Actin Network Assembly During Neutrophil Migration
For efficient polarity and migration, cells need to regulate the magnitude and spatial distribution of actin assembly. This process is coordinated by reciprocal interactions between the actin cytoskeleton and mechanical forces. Actin polymerization-based protrusion increases tension in the plasma membrane, which in turn acts as a long-range inhibitor of actin assembly. These interactions form a negative feedback circuit that limits the magnitude of membrane tension in neutrophils and prevents expansion of the existing front and the formation of secondary fronts. It has been suggested that the plasma membrane directly inhibits actin assembly by serving as a physical barrier that opposes protrusion. Here we show that efficient control of actin polymerization-based protrusion requires an additional mechanosensory feedback cascade that indirectly links membrane tension with actin assembly. Specifically, elevated membrane tension acts through phospholipase D2 (PLD2) and the mammalian target of rapamycin complex 2 (mTORC2) to limit actin nucleation. In the absence of this pathway, neutrophils exhibit larger leading edges, higher membrane tension, and profoundly defective chemotaxis. Mathematical modeling suggests roles for both the direct (mechanical) and indirect (biochemical via PLD2 and mTORC2) feedback loops in organizing cell polarity and motility-the indirect loop is better suited to enable competition between fronts, whereas the direct loop helps spatially organize actin nucleation for efficient leading edge formation and cell movement. This circuit is essential for polarity, motility, and the control of membrane tension.
Journal Article