Empirical likelihood inference for parametric and nonparametric parts in functional coefficient ARCH-M models is investigated in this paper. Firstly, the kernel smoothing technique is used to estimate coefficient function δ(x). In this way we obtain an estimated function with parameter β.Secondly, the empirical likelihood method is developed to estimate the parameter β. An estimated empirical log-likelohood ratio is proved to be asymptotically standard chi-squred, and the maximum empirical likelihood estimation(MELE) for β is shown to be asymptotically normal. Finally, based on the MELE of β, the empirical likelihood approach is again applied to reestimate the nonparametric part δ(x). The empirical log-likelohood ratio for δ(x) is proved to be also asymptotically standard chi-squred. Simulation study shows that the proposed method works better than the normal approximation method in terms of average areas of confidence regions for β, and the empirical likelihood confidence belt for δ(x) performs well. 相似文献
A selective and sensitive liquid chromatography–tandem mass spectrometry method was developed for simultaneous determination of etoricoxib in human plasma. Chromatography was performed on an Acquity UPLC HSS T3 column (1.8 μm, 50 × 2.1 mm), with a flow rate of 0.600 mL/min, using a gradient elution with acetonitrile and water which contained 2 mm ammonium acetate as the mobile phase. Detection was carried out on Triple QuadTM 5500 mass spectrometer under positive‐ion multiple reaction monitoring mode. The respective mass transitions used for quantification of etoricoxib and etoricoxib‐d3 were m/z 359.0 → 280.1 and m/z 362.0 → 280.2. Calibration curves were linear over the concentration range of 5–5000 ng/mL. The validated method was applied in the pharmacokinetic study of etoricoxib in Chinese healthy volunteers under fed and fasted conditions. After a single oral dose of 120 mg, the main pharmacokinetic parameters of etoricoxib in fasted and fed groups were respectively as follows: peak concentration, 2364.78 ± 538.01 and 1874.55 ± 367.90 ng/mL; area under the concentration–time curve from 0 to 120 h, 44,605.53 ± 15,266.66 and 43,516.33 ± 12,425.91 ng h/mL; time to peak concentration, 2.00 and 2.50 h; and half‐life, 24.08 ± 10.06 and 23.64± 6.72 h. High‐fat food significantly reduced the peak concentration of etoricoxib (p = 0.001) but had no effect on the area under the concentration–time curve. 相似文献
Three ruthenium(II) polypyridyl complexes with 5-amino-1,10-phenanthroline ligands have been successfully designed and synthesized. They have been fully characterized by ESI-MS, ESI-HRMS, 1H NMR, and elemental analyses. The photophysical and electrochemical properties of the three complexes have been investigated in organic solvent. The geometrical configuration and the electron density distribution in the frontier molecular orbitals of the three complexes have been studied. The three complexes show metal-to-ligand charge transfer (1MLCT) absorption at 445 nm, and intense triplet metal-to-ligand (3MLCT) emission at around 619 nm in fluid solution at 298 K and 580 nm in low-temperature glass. Electrochemical studies of the three complexes are consistent with one RuIII/II reversible couple at around 1.31 V accompanied by three ligand-centered reduction couples.
Two new complexes, namely [Cu6L6] ( 1 ) and [Zn(HL)2] ( 2 ) (H2L = N‐(1‐phenyl‐3‐methyl‐4‐propenylidene‐5‐pyrazolone)‐2‐furancarboxylic acid hydrazide), have been synthesized and characterized. Single crystal X‐ray analysis indicates that complex 1 has a hexanuclear structure and complex 2 exhibits a mononuclear structure. The DNA/bovine serum albumin (BSA) binding properties of complexes 1 and 2 were investigated by absorption spectroscopy and fluorescence quenching. Both complexes could effectively intercalate to DNA with calculated quenching constants of 2.6 × 105 and 1.25 × 105 M?1, respectively. The quenching mechanism of the intrinsic fluorescence of BSA by the complexes was found to be a static one. The cytotoxicities of 1 and 2 were investigated in two human tumor cell lines, human esophageal cancer cells (Eca‐109) and cervical cancer cells (HeLa). Complex 1 exhibits higher antitumor activity than 2 . Furthermore, 1 can inhibit HeLa cells by inducing apoptosis and G0/G1 phase cell cycle arrest. All results demonstrate that 1 and 2 both have DNA/BSA binding capacity and antitumor activity. 相似文献
Two LnIII ions are sandwiched by dinuclear CoII building blocks derived from a tris‐triazamacrocyclic ligand bearing pendant carboxylic acid functionality, 1,3,5‐tris((4,7‐bis(2‐carboxyethyl)‐1,4,7‐triazacyclonon‐1‐yl)methyl)‐benzene (H6L), giving rising to two nanoscale heterometallic metal–organic cages formulated as [Co4Ln2(LH2.5)2(H2O)4]·(ClO4)6·NO3·nH2O [Ln = Dy, n = 12 ( 1 ); Ln = Yb, n = 9 ( 2 )], whose internal cavity accommodates a guest NO3? anion. Their hexanuclear cage‐like architectures are maintained both in solution and solid states as confirmed by mass spectrum as well as X‐ray diffraction experiments. These two cages display ligand‐based fluorescence emissions and therefore both were chosen to be operated as fluorescent chemosensors for the detection of nitroaromatic compounds. Attractively, these metal–organic cages allow highly selective and sensitive detection of picric acid (PA) over other nitroaromatics in solution and suspension, and the fluorescence resonance energy transfer (FRET) between the cage probes and PA is mainly responsible for the remarkable detection efficiency. 相似文献
Implementing sustainable energy conversion and storage technologies is highly reliant on crucial oxygen electrocatalysis, such as the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). However, the pursuit of low cost, energetic efficient and robust bifunctional catalysts for OER and ORR remains a great challenge. Herein, the novel Na-ion-deficient Na2−xCoP2O7 catalysts are proposed to efficiently electrocatalyze OER and ORR in alkaline solution. The engineering of Na-ion deficiency can tune the electronic structure of Co, and thus tailor the intrinsically electrocatalytic performance. Among the sodium cobalt phosphate catalysts, the Na1.95CoP2O7 (NCPO5) catalyst exhibits the lowest ΔE (EJ10,OER−EJ−1,ORR) of only 0.86 V, which favorably outperforms most of the reported non-noble metal catalysts. Moreover, the Na-ion deficiency can stabilize the phase structure and morphology of NCPO5 during the OER and ORR processes. This study highlights the Na-ion deficient Na2−xCoP2O7 as a promising class of low-cost, highly active and robust bifunctional catalysts for OER and ORR. 相似文献
Sodium/potassium-ion batteries (SIBs/PIBs) arouse intensive interest on account of the natural abundance of sodium/potassium resources, the competitive cost and appropriate redox potential. Nevertheless, the huge challenge for SIBs/PIBs lies in the scarcity of an anode material with high capacity and stable structure, which are capable of accommodating large-size ions during cycling. Furthermore, using sustainable natural biomass to fabricate electrodes for energy storage applications is a hot topic. Herein, an ultra-small few-layer nanostructured MoSe2 embedded on N, P co-doped bio-carbon is reported, which is synthesized by using chlorella as the adsorbent and precursor. As a consequence, the MoSe2/NP-C-2 composite represents exceedingly impressive electrochemical performance for both sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). It displays a promising reversible capacity (523 mAh g−1 at 100 mA g−1 after 100 cycles) and impressive long-term cycling performance (192 mAh g−1 at 5 A g−1 even after 1000 cycles) in SIBs, which are some of the best properties of MoSe2-based anode materials for SIBs to date. To further probe the great potential applications, full SIBs pairing the MoSe2/NP-C-2 composite anode with a Na3V2(PO4)3 cathode also exhibits a satisfactory capacity of 215 mAh g−1 at 500 mA g−1 after 100 cycles. Moreover, it also delivers a decent reversible capacity of 131 mAh g−1 at 1 A g−1 even after 250 cycles for PIBs. 相似文献
A linear optical unambiguous discrimination of hyperentangled Bell states is proposed for two‐photon systems entangled in both the polarization and momentum degrees of freedom (DOFs) assisted by time bin. This unambiguous discrimination scheme can completely identify 16 orthogonal hyperentangled Bell states using only linear optical elements, where the function of the auxiliary entangled Bell state is replaced by time bin. Moreover, the possibility of extending this scheme for distinguishing hyperentangled Bell states in n DOFs is discussed, and it shows that hyperentangled Bell states in n ( ) DOFs can be distinguished with k ( ) auxiliary entangled states of additional DOFs by introducing a time delay, which decreases the auxiliary entanglement resource required for unambiguous discrimination of hyperentangled Bell state. Therefore, this scheme provides a new way for distinguishing hyperentangled states with current technology, which will extend the application of discrimination of hyperentangled states via linear optics to other quantum information protocols besides hyperdense coding schemes in the future. 相似文献
Despite its high morbidity and mortality, contrast‐induced acute kidney injury (CIAKI) remains a diagnostic dilemma because it relies on in vitro detection of insensitive late‐stage blood and urinary biomarkers. We report the synthesis of an activatable duplex reporter (ADR) for real‐time in vivo imaging of CIAKI. ADR is equipped with chemiluminescence and near‐infrared fluorescence (NIRF) signaling channels that can be activated by oxidative stress (superoxide anion, O2.?) and lysosomal damage (N‐acetyl‐β‐d ‐glucosaminidase, NAG), respectively. By virtue of its high renal clearance efficiency (80 % injected doses after 24 h injection), ADR detects sequential upregulation of O2.? and NAG in the kidneys of living mice prior to a significant decrease in glomerular filtration rate (GFR) and tissue damage in the course of CIAKI. ADR outperforms the typical clinical assays and detects CIAKI at least 8 h (NIRF) and up to 16 h (chemiluminescence) earlier. 相似文献