71 research outputs found
Fixed-time safe tracking control of uncertain high-order nonlinear pure-feedback systems via unified transformation functions
summary:In this paper, a fixed-time safe control problem is investigated for an uncertain high-order nonlinear pure-feedback system with state constraints. A new nonlinear transformation function is firstly proposed to handle both the constrained and unconstrained cases in a unified way. Further, a radial basis function neural network is constructed to approximate the unknown dynamics in the system and a fixed-time dynamic surface control (FDSC) technique is developed to facilitate the fixed-time control design for the uncertain high-order pure-feedback system. Combined with the proposed unified transformation function and the FDSC technique, an adaptive fixed-time control strategy is proposed to guarantee the fixed-time tracking. The novel original results of the paper allow to design the independent unified flexible fixed-time control strategy taking into account the actual possible constraints, either present or missing. Numerical examples are presented to demonstrate the proposed fixed-time tracking control strategy
Global metabolic responses of the lenok (Brachymystax lenok) to thermal stress
High temperature is a powerful stressor for fish living in natural and artificial environments, especially for cold water species. Understanding the impact of thermal stress on physiological processes of fish is crucial for better cultivation and fisheries management. However, the metabolic mechanism of cold water fish to thermal stress is still not completely clear. In this study, a NMR-based metabonomic strategy in combination with high throughput RNA-Seq was employed to investigate global metabolic changes of plasma and liver in a typical cold water fish species lenok (Brachymystax lenok) subjected to a sub-lethal high temperature. Our results showed that thermal stress caused multiple dynamic metabolic alterations of the lenok with prolonged stress, including repression of energy metabolism, shifts in lipid metabolism, alterations in amino acid metabolism, changes in choline and nucleotide metabolisms. Specifically, thermal stress induced an activation of glutamate metabolism, indicating that glutamate could be an important biomarker associated with thermal stress. Evidence from Hsp 70 gene expression, blood biochemistry and histology confirmed that high temperature exposure had negative effects on health of the lenok. These findings imply that thermal stress has a severe adverse effect on fish health and demonstrate that the integrated analyses combining NMR-based metabonomics and transcriptome strategy is a powerful approach to enhance our understanding of metabolic mechanisms of fish to thermal stress.</p
Spitzer/IRS 5-35 um Low-Resolution Spectroscopy of the 12 um Seyfert Sample
We present low-resolution 5.5-35 um spectra for 103 galaxies from the 12 um
Seyfert sample, a complete unbiased 12 um flux limited sample of local Seyfert
galaxies selected from the IRAS Faint Source Catalog, obtained with the
Infrared Spectrograph (IRS) on-board Spitzer Space Telescope. For 70 of the
sources observed in the IRS mapping mode, uniformly extracted nuclear spectra
are presented for the first time. We performed an analysis of the continuum
emission, the strength of the Polycyclic Aromatic Hydrocarbon (PAH) and
astronomical silicate features of the sources. We find that on average, the
15-30 um slope of the continuum is alpha_{15-30}=-0.85+-0.61 for Seyfert 1s and
-1.53+-0.84 for Seyfert 2s, and there is substantial scatter in each type.
Moreover, nearly 32% of Seyfert 1s, and 9% of Seyfert 2s, display a peak in the
mid-infrared spectrum at 20 um, which is attributed to an additional hot dust
component. The PAH equivalent width decreases with increasing dust temperature,
asindicated by the global infrared color of the host galaxies. However, no
statistical difference in PAH equivalent width is detected between the two
Seyfert types, 1 and 2, of the same bolometric luminosity. The silicate
features at 9.7 and 18um in Seyfert 1 galaxies are rather weak, while Seyfert
2s are more likely to display strong silicate absorption. Those Seyfert 2s with
the highest silicate absorption also have high infrared luminosity and high
absorption (hydrogen column density N_H>10^23 cm^-2 as measured from the
X-rays. Finally, we propose a new method to estimate the AGN contribution to
the integrated 12 um galaxy emission, by subtracting the "star formation"
component in the Seyfert galaxies, making use of the tight correlation between
PAH 11.2 um luminosity and 12 um luminosity for star forming galaxies.Comment: accepted for publication in Ap
Near-Infrared Survey and Photometric Redshifts in the Extended GOODS-North field
We present deep and -band images in the extended Great Observatories
Origins Deep Survey-North (GOODS-N) field covering an area of 0.22
. The observations were taken using WIRCam on the 3.6-m Canada
France Hawaii Telescope (CFHT). Together with the reprocessed -band
image, the limiting AB magnitudes (in 2" diameter apertures) are
24.7, 24.2, and 24.4 AB mag in the , , and bands,
respectively. We also release a multi-band photometry and photometric redshift
catalog containing 93598 sources. For non-X-ray sources, we obtained a
photometric redshift accuracy with an outlier
fraction . For X-ray sources, which are mainly active galactic
nuclei (AGNs), we cross-matched our catalog with the updated 2M-CDFN X-ray
catalog from Xue et al. (2016) and found that 658 out of 683 X-ray sources have
counterparts. UV data are included in the photometric redshift
computation for the X-ray sources to give with
. Our approach yields more accurate photometric redshift estimates
compared to previous works in this field. In particular, by adopting AGN-galaxy
hybrid templates, our approach delivers photometric redshifts for the X-ray
counterparts with fewer outliers compared to the 3D-HST catalog, which fit
these sources with galaxy-only templates
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MicroRNA-378 enhances inhibitory effect of curcumin on glioblastoma
Glioblastoma multiforme is the most aggressive and common primary brain tumor, and is virtually incurable due to its therapeutic resistance to radiation and chemotherapy. Curcumin is a well-known phytochemical exhibiting antitumor activity on many human cancers including glioblastoma multiforme. Given the unique miRNA expression profiles in cancer cells compared to non-cancerous cells, we investigated whether these miRNA could be used to cancer therapy. In this report we show that miR-378, a glioblastoma multiforme down regulated miRNA, may enhance the inhibitory effect of curcumin on this cancer growth. Our results indicated that the inhibitory effect of curcumin was enhanced in miR-378-expressing stable U87 cells in vitro and in vivo, compared to control cells. MiR-378 was found to target p-p38 expression, underlying the observed phenotypic changes. Thus, we concluded that miR-378 enhances the response of glioblastoma multiforme to curcumin treatment, by targeting p38
Local Benchmarks for the Evolution of Major-Merger Galaxies -- Spitzer Observations of a K-Band Selected Sample
We present Spitzer observations for a sample of close major-merger galaxy
pairs (KPAIR sample) selected from 2MASS/SDSS-DR3 cross-matches. The goals are
to study the star formation activity in these galaxies and to set a local bench
mark for the cosmic evolution of close major mergers. The Spitzer KPAIR sample
(27 pairs, 54 galaxies) includes all spectroscopically confirmed S+S and S+E
pairs in a parent sample that is complete for primaries brighter than K=12.5
mag, projected separations of 5< s < 20 kpc/h, and mass ratios<2.5. The Spitzer
data consist of images in 7 bands (3.6, 4.5, 5.8, 8, 24, 70, 160 um). Compared
to single spiral galaxies in a control sample, only spiral galaxies in S+S
pairs show significantly enhanced specific star formation rate (sSFR=SFR/M),
whereas spiral galaxies in S+E pairs do not. Furthermore, the SFR enhancement
of spiral galaxies in S+S pairs is highly mass-dependent. Only those with \rm
M \gsim 10^{10.5} M_\sun show significant enhancement. Relatively low mass
(\rm M \sim 10^{10} M_\sun) spirals in S+S pairs have about the same SFR/M
compared to their counterparts in the control sample. There is evidence for a
correlation between the global star formation activities (but not the nuclear
activities) of the component galaxies in massive S+S major-merger pairs (the
"Holmberg effect"). There is no significant difference in the SFR/M between the
primaries and the secondaries, nor between spirals of SEP<1 and those of SEP.1.
The contribution of KPAIR galaxies to the cosmic SFR density in the local
universe is only 1.7%.Comment: 73 pages; accpected by Ap
Noema formIng Cluster survEy (NICE): Discovery of a starbursting galaxy group with a radio-luminous core at z=3.95
The study of distant galaxy groups and clusters at the peak epoch of star
formation is limited by the lack of a statistically and homogeneously selected
and spectroscopically confirmed sample. Recent discoveries of concentrated
starburst activities in cluster cores have opened a new window to hunt for
these structures based on their integrated IR luminosities. Hereby we carry out
the large NOEMA (NOrthern Extended Millimeter Array) program targeting a
statistical sample of infrared-luminous sources associated with overdensities
of massive galaxies at z>2, the Noema formIng Cluster survEy (NICE). We present
the first result from the ongoing NICE survey, a compact group at z=3.95 in the
Lockman Hole field (LH-SBC3), confirmed via four massive (M_star>10^10.5M_sun)
galaxies detected in CO(4-3) and [CI](1-0) lines. The four CO-detected members
of LH-SBC3 are distributed over a 180 kpc physical scale, and the entire
structure has an estimated halo mass of ~10^13Msun and total star formation
rate (SFR) of ~4000Msun/yr. In addition, the most massive galaxy hosts a
radio-loud AGN with L_1.4GHz, rest = 3.0*10^25W/Hz. The discovery of LH-SBC3
demonstrates the feasibility of our method to efficiently identify high-z
compact groups or forming cluster cores. The existence of these starbursting
cluster cores up to z~4 provides critical insights into the mass assembly
history of the central massive galaxies in clusters.Comment: 7 pages, 7 figures, submitted to A&
Oridonin induces apoptosis and cell cycle arrest of gallbladder cancer cells via the mitochondrial pathway
Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke
Importance
It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy.
Objective
To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO.
Design, Setting, and Participants
This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy.
Main Outcomes and Measures
The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours.
Results
Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo.
Conclusions and Relevance
Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172
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