709 research outputs found

    μ3-Dodeca­tungsto(V,VI)aluminato-κ3 O:O′:O′′-tris­[aqua­bis­(ethyl­ene­diamine-κ2 N,N′)copper(II)]

    Get PDF
    The title compound, [AlCu3W12O40(C2H8N2)6(H2O)3], was prepared under hydro­thermal conditions. The Cu2+ ion displays an elongated octa­hedral geometry defined by one bridging O atom from the polyoxidoanion and a coordinated water mol­ecule in axial positions and four N atoms of the two chelating ethyl­enediamine (en) ligands in equatorial positions. The one-electron reduced [AlW12O40]6− anion coordinates three [Cu(en)(H2O)]2+ fragments, generating a neutral tri-supported Keggin-type polyoxidometalate (POM). This tri-supported POM is located in a special position of symmetry and therefore O atoms from the central AlO4 tetra­hedron are disordered over two sets of sites. Disorder is also observed for three other bridging O atoms of the POM. In the crystal, mol­ecules are connected via N—H⋯O and O—H⋯O hydrogen bonds, forming a three-dimensional framework

    Strategies for Searching Video Content with Text Queries or Video Examples

    Full text link
    The large number of user-generated videos uploaded on to the Internet everyday has led to many commercial video search engines, which mainly rely on text metadata for search. However, metadata is often lacking for user-generated videos, thus these videos are unsearchable by current search engines. Therefore, content-based video retrieval (CBVR) tackles this metadata-scarcity problem by directly analyzing the visual and audio streams of each video. CBVR encompasses multiple research topics, including low-level feature design, feature fusion, semantic detector training and video search/reranking. We present novel strategies in these topics to enhance CBVR in both accuracy and speed under different query inputs, including pure textual queries and query by video examples. Our proposed strategies have been incorporated into our submission for the TRECVID 2014 Multimedia Event Detection evaluation, where our system outperformed other submissions in both text queries and video example queries, thus demonstrating the effectiveness of our proposed approaches

    Structure-Mediated Excitation of Air Plasma and Silicon Plasma Expansion in Femtosecond Laser Pulses Ablation

    Get PDF
    Femtosecond laser-induced surface structures upon multiple pulses irradiation are strongly correlated with the pulse number,which in turn significantly affects successive laser-material interactions. By recording the dynamics of femtosecond laser ablation of silicon using time-resolved shadowgraphy, here we present direct visualization of the excitation of air plasma induced by the reflected laser during the second pulse irradiation.The interaction of the air plasma and silicon plasma is found to enhance the shockwave expansion induced by silicon ablation in the longitudinal direction, showing anisotropic expansion dynamics in different directions. We further demonstrate the vanishing of air plasma as the pulse number increases because of the generation of a rough surface without light focusing ability. In the scenario, the interaction of air plasma and silicon plasma disappears; the expansion of the silicon plasma and shockwave restores its original characteristic that is dominated by the laser-material coupling.The results show that the excitation of air plasma and the laser-material coupling involved in laser-induced plasma and shockwave expansion are structure mediated and dependent on the pulse number, which is of fundamental importance for deep insight into the nature of laser-material interactions during multiple pulses ablation

    Method of determining cosmological parameter ranges with samples of candles with an intrinsic distribution

    Full text link
    In this paper, the effect of the intrinsic distribution of cosmological candles is investigated. We find that, in the case of a narrow distribution, the deviation of the observed modulus of sources from the expected central value could be estimated within a ceratin range. We thus introduce a lower and upper limits of χ2\chi ^{2}, χmin2\chi_{\min}^{2} and χmax2 \chi_{\max}^{2}, to estimate cosmological parameters by applying the conventional minimizing χ2\chi ^{2} method. We apply this method to a gamma-ray burst (GRB) sample as well as to a combined sample including this GRB sample and an SN Ia sample. Our analysis shows that: a) in the case of assuming an intrinsic distribution of candles of the GRB sample, the effect of the distribution is obvious and should not be neglected; b) taking into account this effect would lead to a poorer constraint of the cosmological parameter ranges. The analysis suggests that in the attempt of constraining the cosmological model with current GRB samples, the results tend to be worse than what previously thought if the mentioned intrinsic distribution does exist.Comment: 6 pages,4 figures,1 tables.Data updated. Main conclusion unchange

    Antinociceptive effects of morphine and naloxone in mu-opioid receptor knockout mice transfected with the MORS196A gene

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Opioid analgesics such as morphine and meperidine have been used to control moderate to severe pain for many years. However, these opioids have many side effects, including the development of tolerance and dependence after long-term use, which has limited their clinical use. We previously reported that mutations in the mu-opioid receptors (MOR) S196L and S196A rendered them responsive to the opioid antagonist naloxone without altering the agonist phenotype. In MORS196A knock-in mice, naloxone and naltrexone were antinociceptive but did not cause tolerance or physical dependence. In this study we delivery this mutated MOR gene into pain related pathway to confirm the possibility of <it>in vivo </it>transfecting MORS196A gene and using naloxone as a new analgesic agent.</p> <p>Methods</p> <p>The MOR-knockout (MOR-KO) mice were used to investigate whether morphine and naloxone could show antinociceptive effects when MORS196A gene was transfected into the spinal cords of MOR-KO mice. Double-stranded adeno-associated virus type 2 (dsAAV2) was used to deliver the MORS196A-enhanced green fluorescence protein (EGFP) gene by microinjected the virus into the spinal cord (S2/S3) dorsal horn region. Tail-flick test was used to measure the antinociceptive effect of drugs.</p> <p>Results</p> <p>Morphine (10 mg/kg, s.c.) and naloxone (10 mg/kg, s.c.) had no antinociceptive effects in MOR-KO mice before gene transfection. However, two or three weeks after the MOR-S196A gene had been injected locally into the spinal cord of MOR-KO mice, significant antinociceptive effects could be induced by naloxone or morphine. On the other hand, only morphine but not naloxone induced significant tolerance after sub-chronic treatment.</p> <p>Conclusion</p> <p>Transfecting the MORS196A gene into the spinal cord and systemically administering naloxone in MOR-KO mice activated the exogenously delivered mutant MOR and provided antinociceptive effect without causing tolerance. Since naloxone will not activate natural MOR in normal animals or humans, it is expected to produce fewer side effects and less tolerance and dependence than traditional opioid agonists do.</p

    Analysis of Current Status and Strategies of Retinopathy of Prematurity Screening during 6 Years in Local Regions of China: Implication and Caution

    Get PDF
    Purpose. To understand the current status of retinopathy of prematurity (ROP) screening in a province of North China. Methods. We retrospectively analyzed 5651 cases with ROP screening in the Provincial Screening Center of Hebei Province from January 2008 to December 2013. Results. 14.98% of all ROP patients and 1.56% of severe ROP patients required treatment. All the severe ROP patients met the criteria of screening. Severe ROP patients were detected at recommended initial screening time (4–6 weeks after birth). The frequency of other ocular diseases was 8.03%, in which the main disease was fundus hemorrhage. In 2665 more mature and unqualified infants, only 2 retinoblastoma and 2 familial exudative vitreoretinopathy were detected, which indicates the advantage of early diagnosis and treatment based on fundus examination. Conclusions. It is suggested that the standard of GA < 32 weeks and/or BW < 1800 g could be served as the screening criteria in the local region for ROP screening. 4 weeks after birth is the most appropriate time for initial screening
    corecore