12,553 research outputs found
Daytime temperature is sensed by phytochrome B in Arabidopsis through a transcriptional activator HEMERA.
Ambient temperature sensing by phytochrome B (PHYB) in Arabidopsis is thought to operate mainly at night. Here we show that PHYB plays an equally critical role in temperature sensing during the daytime. In daytime thermosensing, PHYB signals primarily through the temperature-responsive transcriptional regulator PIF4, which requires the transcriptional activator HEMERA (HMR). HMR does not regulate PIF4 transcription, instead, it interacts directly with PIF4, to activate the thermoresponsive growth-relevant genes and promote warm-temperature-dependent PIF4 accumulation. A missense allele hmr-22, which carries a loss-of-function D516N mutation in HMR's transcriptional activation domain, fails to induce the thermoresponsive genes and PIF4 accumulation. Both defects of hmr-22 could be rescued by expressing a HMR22 mutant protein fused with the transcriptional activation domain of VP16, suggesting a causal relationship between HMR-mediated activation of PIF4 target-genes and PIF4 accumulation. Together, this study reveals a daytime PHYB-mediated thermosensing mechanism, in which HMR acts as a necessary activator for PIF4-dependent induction of temperature-responsive genes and PIF4 accumulation
Spontaneous Symmetry Breaking and Dynamic Phase Transition in Monolayer Silicene
The (r3xr3)R30{\deg} honeycomb of silicene monolayer on Ag(111) was found to
undergo a phase transition to two types of mirror-symmetric boundary-separated
rhombic phases at temperatures below 40 K by scanning tunneling microscopy. The
first-principles calculations reveal that weak interactions between silicene
and Ag(111) drive the spontaneous ultra buckling in the monolayer silicene,
forming two energy-degenerate and mirror-symmetric (r3xr3)R30{\deg} rhombic
phases, in which the linear band dispersion near Dirac point (DP) and a
significant gap opening (150 meV) at DP were induced. The low transition
barrier between these two phases enables them interchangeable through dynamic
flip-flop motion, resulting in the (r3xr3)R30{\deg} honeycomb structure
observed at high temperature.Comment: 12 pages, 4 figure
SIRT3 Protects Rotenone-induced Injury in SH-SY5Y Cells by Promoting Autophagy through the LKB1-AMPK-mTOR Pathway.
SIRT3 is a class III histone deacetylase that modulates energy metabolism, genomic stability and stress resistance. It has been implicated as a potential therapeutic target in a variety of neurodegenerative diseases, including Parkinson's disease (PD). Our previous study demonstrates that SIRT3 had a neuroprotective effect on a rotenone-induced PD cell model, however, the exact mechanism is unknown. In this study, we investigated the underlying mechanism. We established a SIRT3 stable overexpression cell line using lentivirus infection in SH-SY5Y cells. Then, a PD cell model was established using rotenone. Our data demonstrate that overexpression of SIRT3 increased the level of the autophagy markers LC3 II and Beclin 1. After addition of the autophagy inhibitor 3-MA, the protective effect of SIRT3 diminished: the cell viability decreased, while the apoptosis rate increased; α-synuclein accumulation enhanced; ROS production increased; antioxidants levels, including SOD and GSH, decreased; and MMP collapsed. These results reveal that SIRT3 has neuroprotective effects on a PD cell model by up-regulating autophagy. Furthermore, SIRT3 overexpression also promoted LKB1 phosphorylation, followed by activation of AMPK and decreased phosphorylation of mTOR. These results suggest that the LKB1-AMPK-mTOR pathway has a role in induction of autophagy. Together, our findings indicate a novel mechanism by which SIRT3 protects a rotenone-induced PD cell model through the regulation of autophagy, which, in part, is mediated by activation of the LKB1-AMPK-mTOR pathway
Evaluation of medication treatment for Alzheimer's disease on clinical evidence
<p><strong>Objective</strong> To formulate the best treatment plan for Alzheimer's disease patients by evaluating the therapeutic efficacy and side effect of various evidence-based programs. <strong>Methods</strong> Alzheimer's disease, donepezil, rivastigmine, galantamine, memantine, rosiglitazone, etc. were defined as retrieval words. PubMed, Cochrane Library, Wanfang Data and China National Knowledge Infrastructure (CNKI) databases were used with applying of manual searching. Systematic reviews, randomized controlled trials (RCT), controlled clinical trials and case-observation studies were collected and evaluated by Jadad Scale. <strong>Results</strong> After screening, 33 selected resources included 14 systematic reviews, 14 randomized controlled trials, 4 controlled clinical trials and 1 case-observation study. According to Jadad Scale, total 28 articles were evaluated to be high quality (12 with score 4, 10 score 5, 6 score 7), and 5 were low quality with score 3. It was summarized as follows: 1) Alzheimer's disease is a progressive neurodegenerative disease for which no cure exists. To date, only symptomatic treatments with cholinesterase inhibitors (donepezil, rivastigmine, galantamine) and an N-methyl-D-aspartate (NMDA) receptor noncompetitive antagonist (memantine), are effective and well tolerated to counterbalance the neurotransmitter disturbance, but cannot limit or impact on disease progression. 2) Disease modifying drug is an potential agent, with persistent effect on slowing the progression of structural damage, and can be detected even after withdrawing the treatment. Many types of disease modifying drugs are undergoing clinical trials. <strong>Conclusions</strong> Using evidence-based medicine methods can provide best clinical evidence on Alzheimer's disease treatment.</p><p> </p><p>doi: 10.3969/j.issn.1672-6731.2014.03.009</p
Data Processing Pipeline for Pointing Observations of Lunar-based Ultraviolet Telescope
We describe the data processing pipeline developed to reduce the pointing
observation data of Lunar-based Ultraviolet Telescope (LUT), which belongs to
the Chang'e-3 mission of the Chinese Lunar Exploration Program. The pointing
observation program of LUT is dedicated to monitor variable objects in a
near-ultraviolet (245-345 nm) band. LUT works in lunar daytime for sufficient
power supply, so some special data processing strategies have been developed
for the pipeline. The procedures of the pipeline include stray light removing,
astrometry, flat fielding employing superflat technique, source extraction and
cosmic rays rejection, aperture and PSF photometry, aperture correction, and
catalogues archiving, etc. It has been intensively tested and works smoothly
with observation data. The photometric accuracy is typically ~0.02 mag for LUT
10 mag stars (30 s exposure), with errors come from background noises,
residuals of stray light removing, and flat fielding related errors. The
accuracy degrades to be ~0.2 mag for stars of 13.5 mag which is the 5{\sigma}
detection limit of LUT.Comment: 10 pages, 7 figures, 4 tables. Minor changes and some expounding
words added. Version accepted for publication in Astrophysics and Space
Science (Ap&SS
Prevalence of Kaposi’s sarcoma-associated herpesvirus in Uygur and Han populations from the Urumqi and Kashgar regions of Xinjiang, China
Kaposi’s sarcoma-associated herpesvirus (KSHV) is the infectious etiologic agent associated with Kaposi’s sarcoma (KS), primary effusion lymphoma, and multicentric Castleman disease. It has been shown that high KSHV prevalence and high incidence of both classic KS and AIDSassociated KS are found mostly among people of Uygur ethnicity in Xinjiang, while people of Han ethnicity in Xinjiang have a higher KSHV seroprevalence than those of other Han populations in mainland China. However, it is still unclear why there is such geographical and population variation in KSHV distribution in China. In this work, we focused on the populations in the Kashgar region and Urumqi area, where a total of 1294 research subjects were randomly selected to investigate the potential correlation between KSHV prevalence and different ethnicities in endemic areas of Xinjiang, and to determine risk factors that may affect KSHV infection rates or KS incidence. We identified a high seroprevalence of KSHV and high peripheral blood DNA infection in the general Uygur and Han populations in both Urumqi and Kashgar regions of Xinjiang, and determined that advancing age, low education level, and stationary population status affect KSHV infection rates. Further, KSHV-positive Uygur participants were shown to have higher prevalence of neutralizing antibodies and neutralizing antibody titers than KSHV-positive Han participants
Asymmetric spin-wave dispersion due to Dzyaloshinskii-Moriya interaction in an ultrathin Pt/CoFeB film
Employing Brillouin spectroscopy, strong interfacial Dzyaloshinskii-Moriya
interactions have been observed in an ultrathin Pt/CoFeB film. Our
micromagnetic simulations show that spin-wave nonreciprocity due to asymmetric
surface pinning is insignificant for the 0.8nmthick CoFeB film studied. The
observed high asymmetry of the monotonic spin wave dispersion relation is thus
ascribed to strong Dzyaloshinskii-Moriya interactions present at the Pt/CoFeB
interface. Our findings should further enhance the significance of CoFeB as an
important material for magnonic, spintronic and skyrmionic applications.Comment: 12 pages, 4 figure
High throughput 16SrRNA gene sequencing reveals the correlation between Propionibacterium acnes and sarcoidosis
Sequences of the unique OTUs. (XLS 3616Â kb
On Optimal Neighbor Discovery
Mobile devices apply neighbor discovery (ND) protocols to wirelessly initiate
a first contact within the shortest possible amount of time and with minimal
energy consumption. For this purpose, over the last decade, a vast number of ND
protocols have been proposed, which have progressively reduced the relation
between the time within which discovery is guaranteed and the energy
consumption. In spite of the simplicity of the problem statement, even after
more than 10 years of research on this specific topic, new solutions are still
proposed even today. Despite the large number of known ND protocols, given an
energy budget, what is the best achievable latency still remains unclear. This
paper addresses this question and for the first time presents safe and tight,
duty-cycle-dependent bounds on the worst-case discovery latency that no ND
protocol can beat. Surprisingly, several existing protocols are indeed optimal,
which has not been known until now. We conclude that there is no further
potential to improve the relation between latency and duty-cycle, but future ND
protocols can improve their robustness against beacon collisions.Comment: Conference of the ACM Special Interest Group on Data Communication
(ACM SIGCOMM), 201
The Photometric System of Tsinghua-NAOC 80-cm Telescope at NAOC Xinglong Observatory
Tsinghua-NAOC (National Astronomical Observatories of China) Telescope
(hereafter, TNT) is an 80-cm Cassegrain reflecting telescope located at
Xinglong bservatory of NAOC, with main scientific goals of monitoring various
transients in the universe such as supernovae, gamma-ray bursts, novae,
variable stars, and active galactic nuclei. We present in this paper a
systematic test and analysis of the photometric performance of this telescope.
Based on the calibration observations on twelve photometric nights, spanning
the period from year 2004 to year 2012, we derived an accurate transformation
relationship between the instrumental magnitudes and standard Johnson
and Cousins magnitudes. In particular, the color terms and the
extinction coefficients of different passbands are well determined. With these
data, we also obtained the limiting magnitudes and the photometric precision of
TNT. It is worthwhile to point out that the sky background at Xinglong
Observatory may become gradually worse over the period from year 2005 to year
2012 (e.g., 21.4 mag vs. 20.1 mag in the V band).Comment: 12 pages,9 figures, accepted by RA
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