1,712 research outputs found
Quantitative observability for one-dimensional Schr\"odinger equations with potentials
In this note, we prove the quantitative observability with an explicit
control cost for the 1D Schr\"odinger equation over with
real-valued, bounded continuous potential on thick sets. Our proof relies on
different techniques for low-frequency and high-frequency estimates. In
particular, we extend the large time observability result for the 1D free
Schrodinger equation in Theorem 1.1 of Huang-Wang-Wang [20] to any short time.
As another byproduct, we extend the spectral inequality of Lebeau-Moyano [27]
for real-analytic potentials to bounded continuous potentials in the
one-dimensional case.Comment: 26 pages, comments are welcom
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Stemness factor Sall4 is required for DNA damage response in embryonic stem cells.
Mouse embryonic stem cells (ESCs) are genetically more stable than somatic cells, thereby preventing the passage of genomic abnormalities to their derivatives including germ cells. The underlying mechanisms, however, remain largely unclear. In this paper, we show that the stemness factor Sall4 is required for activating the critical Ataxia Telangiectasia Mutated (ATM)-dependent cellular responses to DNA double-stranded breaks (DSBs) in mouse ESCs and confer their resistance to DSB-induced cytotoxicity. Sall4 is rapidly mobilized to the sites of DSBs after DNA damage. Furthermore, Sall4 interacts with Rad50 and stabilizes the Mre11-Rad50-Nbs1 complex for the efficient recruitment and activation of ATM. Sall4 also interacts with Baf60a, a member of the SWI/SNF (switch/sucrose nonfermentable) ATP-dependent chromatin-remodeling complex, which is responsible for recruiting Sall4 to the site of DNA DSB damage. Our findings provide novel mechanisms to coordinate stemness of ESCs with DNA damage response, ensuring genomic stability during the expansion of ESCs
Electrografting of amino-TEMPO on graphene oxide and electrochemically reduced graphene oxide for electrocatalytic applications.
4-Amino-2,2,6,6-tetramethyl-1-piperridine N-oxyl (4-amino-TEMPO), an electroactive nitroxide radical, was attached to the surface of graphene oxide (GO) and electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode by a simple, rapid and green electrografting method. The electroactive interfaces were analyzed by X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). The calculated surface coverage for 4-amino-TEMPO is up to 1.55 × 10− 9 mol·cm− 2. The modified electroactive interface exhibited excellent electrocatalytic activity towards the electro-oxidation of reduced glutathione (GSH) and hydrogen peroxide (H2O2)
In silico discovery of human natural antisense transcripts
BACKGROUND: Several high-throughput searches for ppotential natural antisense transcripts (NATs) have been performed recently, but most of the reports were focused on cis type. A thorough in silico analysis of human transcripts will help expand our knowledge of NATs. RESULTS: We have identified 568 NATs from human RefSeq RNA sequences. Among them, 403 NATs are reported for the first time, and at least 157 novel NATs are trans type. According to the pairing region of a sense and antisense RNA pair, hNATs are divided into 6 classes, of which about 87% involve 5' or 3' UTR sequences, supporting the regulatory role of UTRs. Among a total of 535 NAT pairs related with splice variants, 77.4% (414/535) have their pairing regions affected or completely eliminated by alternative splicing, suggesting significant relationship of alternative splicing and antisense-directed regulation. The extensive occurrence of splice variants in hNATs and other multiple pairing patterns results in a one-to-many relationship, allowing the formation of complex regulation networks. Based on microarray data from Stanford Microarray Database, two hNAT pairs were found to display significant inverse expression patterns before and after insulin injection. CONCLUSION: NATs might carry out more extensive and complex functions than previously thought. Combined with endogenous micro RNAs, hNATs could be regarded as a special group of transcripts contributing to the complex regulation networks
Curcumin Protects Intestinal Mucosal Barrier Function of Rat Enteritis via Activation of MKP-1 and Attenuation of p38 and NF-κB Activation
BACKGROUND: Intestinal mucosa barrier (IMB) dysfunction results in many notorious diseases for which there are currently few effective treatments. We studied curcumin's protective effect on IMB and examined its mechanism by using methotrexate (MTX) induced rat enteritis model and lipopolysaccharide (LPS) treated cell death model. METHODOLOGY/PRINCIPAL FINDINGS: Curcumin was intragastrically administrated from the first day, models were made for 7 days. Cells were treated with curcumin for 30 min before exposure to LPS. Rat intestinal mucosa was collected for evaluation of pathological changes. We detected the activities of D-lactate and diamine oxidase (DAO) according to previous research and measured the levels of myeloperoxidase (MPO) and superoxide dismutase (SOD) by colorimetric method. Intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) were determined by RT-PCR and IL-10 production was determined by ELISA. We found Curcumin decreased the levels of D-lactate, DAO, MPO, ICAM-1, IL-1β and TNF-α, but increased the levels of IL-10 and SOD in rat models. We further confirmed mitogen-activated protein kinase phosphatase-1 (MKP-1) was activated but phospho-p38 was inhibited by curcumin by western blot assay. Finally, NF-κB translocation was monitored by immunofluorescent staining. We showed that curcumin repressed I-κB and interfered with the translocation of NF-κB into nucleus. CONCLUSIONS/SIGNIFICANCE: The effect of curcumin is mediated by the MKP-1-dependent inactivation of p38 and inhibition of NF-κB-mediated transcription. Curcumin, with anti-inflammatory and anti-oxidant activities may be used as an effective reagent for protecting intestinal mucosa barrier and other related intestinal diseases
PrivateDroid: Private Browsing Mode for Android
Abstract—Private browsing mode is a privacy feature adopted by many modern computer browsers. With the increased use of mobile devices and escalating privacy concerns for mobile users, browser applications on mobile devices have also started incorporating private browsing mode. Even so, the use of private browsing mode is limited to the browser applications and cannot be applied directly on other third-party mobile applications. In this paper, we propose PrivateDroid, which provides a private browsing mode for third-party applications on the Android plat-form. First, we discuss three possible approaches of implementing mobile private browsing mode: code instrumentation, an extra sandbox, and a Linux container approach. Then, we implement PrivateDroid, which creates a new sandbox for every application in private mode and destroys the sandbox once the application is closed. After that, we evaluate usability, efficiency and security of the system with 25 popular Android applications. Our design considerations, implementation details, evaluation results, and challenges lay a foundation of private browsing mode on mobile platforms. Index Terms—Mobile Privacy, Private Browsing Mode I
Experimental study on a novel photovoltaic thermal system using amorphous silicon cells deposited on stainless steel
Amorphous silicon (a-Si) cells are able to perform better as temperature increases due to the effect of thermal annealing. a-Si cells have great potential to solve or ease the problems of high power temperature coefficient, large thermal stress caused by temperature fluctuation and gradient, and thick layer of conventional crystalline silicon cell-related photovoltaic/thermal (PV/T) collectors. In this paper, an innovative a-Si PV/T system is developed. It is the first time that a-Si cells deposited on stainless steel have been used in a practical PV/T system. The system comprises of two PV/T collectors. In each collector, there are 8 pieces of solar cells in series. Long-term outdoor performance has been monitored. Experimental results on the thermal efficiency Image 1, electrical efficiency Image 2 and I-V characteristic are presented. The peak instantaneous Image 3 was about 42.49% with the maximum Image 4 of 5.92% on April 2, 2017. The daily average Image 5 and Image 6 were 32.8% and 5.58%. Accordingly, Image 7 ,Image 8, Image 9 and Image 10 on October 27 were 43.47%, 5.69%, 38.65% and 5.22 %. During more than half a year operation, no technical failure of the system has been observed. The feasibility of the a-Si PV/T is preliminarily demonstrated by the prototype
The nucleolar protein NIFK promotes cancer progression via CK1α/β-catenin in metastasis and Ki-67-dependent cell proliferation.
Nucleolar protein interacting with the FHA domain of pKi-67 (NIFK) is a Ki-67-interacting protein. However, its precise function in cancer remains largely uninvestigated. Here we show the clinical significance and metastatic mechanism of NIFK in lung cancer. NIFK expression is clinically associated with poor prognosis and metastasis. Furthermore, NIFK enhances Ki-67-dependent proliferation, and promotes migration, invasion in vitro and metastasis in vivo via downregulation of casein kinase 1α (CK1α), a suppressor of pro-metastatic TCF4/β-catenin signaling. Inversely, CK1α is upregulated upon NIFK knockdown. The silencing of CK1α expression in NIFK-silenced cells restores TCF4/β-catenin transcriptional activity, cell migration, and metastasis. Furthermore, RUNX1 is identified as a transcription factor of CSNK1A1 (CK1α) that is negatively regulated by NIFK. Our results demonstrate the prognostic value of NIFK, and suggest that NIFK is required for lung cancer progression via the RUNX1-dependent CK1α repression, which activates TCF4/β-catenin signaling in metastasis and the Ki-67-dependent regulation in cell proliferation
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