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We have designed and synthesized two novel pyridyl‐quinoxaline ligands, L1 and L2, as well as twelve cobalt, nickel, and copper complexes, 1–6 and 1 a–6 a. Unexpectedly, high regularities in the synthesis of both ligands and complexes were found. Further X‐ray diffraction analyses revealed that the two ligands had similar geometrical configurations, and the structures of twelve complexes were regularly divided into two categories: binuclear and mononuclear, which would be beneficial for elucidating structure‐activity relationships of metal catalysts. In addition, the experimental results showed significant variations in the catalytic performance of methyl methacrylate polymerization with different catalysts. Under the optimum reaction conditions, the mononuclear copper complex 3 a displayed a remarkably high catalytic activity of 2.76×105 g ⋅ mol−1 h−1, generating Poly(methyl methacrylate) with molecular weight of Mn=8.55×105 g ⋅ mol−1 and molecular weight distribution of Đ=1.67.This outcome suggested that copper had the potential to serve as a promising catalytic metal center. [ABSTRACT FROM AUTHOR]

Here, L1 (2‐(pyridin‐2‐yl)quinoxaline) and L2 ((1‐((1H‐pyrrol‐2‐yl)ethylidene)benzene‐1,2‐diamine) ⋅ (1‐(1H‐pyrrol‐2‐yl)ethanone)) were synthesized and reacted with CoCl2 ⋅ 6H2O and NiCl2 ⋅ 6H2O to produce complexes 1–4. We found several interesting pieces of crystal structure information. Firstly, ligands L1 and L2 with completely different molecular structures were obtained by reacting the precursors containing similar N‐heterocycles with 1,2‐diaminobenzene. Secondly, in methanol and DMF solvents, 1 showed two structures, the binuclear and mononuclear cobalt complexes 1 a and 1 b. Finally, the structure of 4 showed the formation of a new 2 : 1 type ligand at eutectic L2 in the presence of a Ni2+ template. Upon treatment with AIBN, 1–4 showed moderate to high activities for MMA polymerization, producing PMMA with low to high molecular weights (2.02∼73.03×104 g⋅mol‐1) and moderate dispersity indices (PDI: 1.72∼3.32). Moreover, 1 b displayed higher catalytic activities (up to 1.138×105 g mol−1 ⋅ h−1), which was 20 times higher than that of 3 and more than 7 times higher than that of 1 a. [ABSTRACT FROM AUTHOR]

This study proposes a novel miniaturized circularly polarized (CP) ultrahigh frequency (UHF) quadrifilar helix antenna for spaceborne applications. The dual‐band operation is realized using four inverted‐U shaped helical strips (IUSHSs) that are rotated and alternately arranged on the four faces of a hollow polyimide cuboid in a sequential rotation manner, which effectively reduces the size of the antenna. Furthermore, the four IUSHSs are connected by a cross‐shape strip at the top of the antenna to control the dual resonant frequencies, resulting in a small dual‐band frequency ratio. The proposed antenna is both lightweight and robust when compared with the conventional miniaturized CP antennas operating at similar bands with similar performance. In particular, its compact radiator provides effective miniaturized spaceborne solution without the need of high‐dielectric coefficient materials. A device for spaceborne application that operates at 402/505 MHz is designed, fabricated, measured, and in‐orbit tested with a weight of 651 g and an effective size of 0.161 × 0.161 × 0.228 λ3402MHz (λ402MHz is the wavelength at 402 MHz). The measured gain and axial ratio of the proposed antenna are better than 5.32 dBi and 2.18 dB, respectively, within 2 and 12 MHz bandwidth for the two bands. The test results proved that the methods used to design the proposed antenna are effective. [ABSTRACT FROM AUTHOR]

Rhizoma coptidis has been used for a long time in China owing to its anti‐bacterial, anti‐diabetes, anti‐hyperlipidemia and anti‐obesity activities. However, the in vivo biotransformation of Rhizoma coptidis is still unclear to date. In this study, a three‐step strategy using UPLC‐Q‐TOF/MS was applied to clarify the in vivo absorbed constituents and metabolites in rats after oral administration of Rhizoma coptidis. First, alkaloids in Rhizoma coptidis extract were identified. Second, six abundant alkaloids (berberine, palmatine, coptisine, epiberberine, jatrorrhizine, and columbamine) were selected as representative prototypes and the metabolic fates of them in rats were investigated to obtain a database of Rhizoma coptidis‐derived metabolites. Finally, the metabolic profiles of Rhizoma coptidis were fully elucidated based on the above‐mentioned results. In summary, 29 alkaloids were identified in Rhizoma coptidis, and a database of Rhizoma coptidis‐derived metabolites was obtained with 144 characterized metabolites. A total of 89 xenobiotics including 12 absorbed constituents and 77 metabolites were identified in dosed rat biosamples. Major metabolic pathways of Rhizoma coptidis were hydroxylation, reduction, methylation, demethylation, demethylenation, desaturation, glucuronidation and sulfation. This is the first systematic study on the in vivo absorbed constituents and metabolic profiling of Rhizoma coptidis and will be beneficial for its further studies. [ABSTRACT FROM AUTHOR]

A novel very‐high frequency (VHF) band spaceborne phased antenna array for satellite‐automatic identification system/VHF data exchange (SAT‐AIS/VDE) applications operating at 159 MHz is proposed in this letter. Element phase shifting is achieved by controlling each element mechanical rotation angle rather than the phase shifter behind each element. Thanks to the new working scheme, the proposed array shows several advantages over its former counterpart, including low cost, high power capacity, and broad phase‐shifting bandwidth. This letter explains the basic principle, and presents a preliminary study on element rotation angle controlled phased antenna array technology, and an eight‐element‐array which is implemented on solar panel supporting plate is designed to validate the concept. [ABSTRACT FROM AUTHOR]

Abstract: The calyces of Physalis alkekengi var. franchetii (Chinese Lantern, JDL) are well‐known as traditional Chinese medicine owing to its various therapeutic effects. However, the bioactive constituents responsible for the pharmacological effects of JDL and their metabolites in vivo are still unclear to date. In this paper, an ultra‐high‐pressure liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry (UHPLC/Q‐TOF‐MS/MS) method was established to identify absorbed constituents and in vivo metabolites in rat biological fluids after oral administration of JDL. Based on the proposed strategy, 33 compounds were observed in dosed rat biosamples. Twelve of 33 compounds were indicated as prototype components of JDL, and 21 compounds were predicted to be metabolites of JDL. Finally, the metabolic pathways were proposed, which were glucuronidation, sulfation, methylation and dehydroxylation for flavonoid constituents and sulfonation and hydroxylation for physalin consitituents. This is the first systematic study on the absorbed constituents and metabolic profiling of JDL and will provide a useful template for screening and characterizing the ingredients and metabolites of traditional Chinese medicine. [ABSTRACT FROM AUTHOR]

A rapid and sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of luteolin, luteolin-7- O- β-D-glucopyranoside, physalin A, physalin D and physalin L in rat plasma. Scutellarein and dexamethasone were used as the internal standards (IS). Plasma samples were prepared by liquid-liquid extraction with ethyl acetate. The five constituents were separated on an Acquity UPLC BEH C18 column (100 mm × 2.1 mm, 1.7 μm). A gradient elution procedure was used with acetonitrile (A)-0.1% aqueous formic acid (B). Mass spectrometric detection was performed in negative ion multiple reaction monitoring mode with an electrospray ionization (ESI) source. This method showed good linearity ( r2 > 0.997) over a concentration range of 2.0-500 ng/mL with a lower limit of quantification of 2.0 ng/mL for all five compounds. The inter- and intra-day accuracy ranged from 91.7 to 104%, and precisions (RSD) were <6.46% for all analytes. The extraction recoveries of all analytes were >85%. This validated method was successfully applied for the first time to the pharmacokinetic study of five ingredients after oral administration of 70% ethanol extract of Chinese lantern in rats. [ABSTRACT FROM AUTHOR]

Rationale Palmatine (PAL), a protopalmatine alkaloid, is an active constituent in a number of medicinal plants. In order to obtain a comprehensive and systematic metabolic profile of PAL, we investigated its metabolites in plasma, liver tissue, bile, urine, and feces samples after intragastrical administration to Sprague-Dawley rats with a dose of 100 mg/kg/day. Methods In this study, a rapid and sensitive method by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/QTOF-MS), and Metabolynx™ software with the mass defect filter (MDF) technique was developed for screening and identification of the metabolites. The structural elucidation of the metabolites was performed by comparing their molecular weights and fragment ions with those of the parent drug. Results As a result, a total of 58 metabolites were identified in rat biological samples including 46 metabolites in urine, 18 metabolites in plasma, 34 metabolites in bile, 26 metabolites in liver tissue, and 10 metabolites in feces. Among them, six major metabolites were fully confirmed using reference standards and others were identified by retention time, accurate mass and fragment ions. Conclusions These results indicated that phase I reactions (demethylation and hydroxylation) and phase II reaction (glucuronidation and sulfation) were the main metabolic pathways of PAL in vivo. This research enhances our understanding of metabolism of PAL in rats, and provides useful information on the action mechanism of PAL. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A fast joint sorting and reduction (FJSR) algorithm is proposed, which involves elementary column operations only, to assist the successive interference cancellation (SIC) detection for multiple‐input multiple‐output (MIMO) systems. Simulation results show that the FJSR‐aided SIC detector achieves good error performance especially when the system scales up, yet requires only a few extra basis updates over the optimal‐ordered SIC detector regardless of the system size. This suggests that FJSR is particularly advantageous to small‐to‐medium scale MIMO systems with strict delay constraints. [ABSTRACT FROM AUTHOR]

Eight eudesmane-type sesquiterpenes - phaeusmanes A-H ( 1- 8) - isolated for the first time in this work, and four others ( 9- 12) isolated for the first time from plants in this work, together with fourteen known eudesmane derivatives, were isolated from the rhizomes of Curcuma phaeocaulis. Their structures were elucidated by 1D and 2D NMR and CD spectroscopy and HRMS. Compound 8 is the first example of a nitrogen-containing eudesmane-type sesquiterpene isolated from the genus Curcuma. Furthermore, inhibitory effects of the isolated compounds on NO production in lipopolysaccharide-activated macrophages were evaluated. Compounds 1, 6, 10, 19, 22, and 24 showed strong inhibitory activities on NO production with IC50 values of 3.2, 4.8, 1.2, 0.8, 3.8, and 0.8 μ M, respectively. Preliminary structure-activity relationships for these compounds are proposed. A possible biogenetic pathway for nitrogen-containing eudesmane-type sesquiterpene 8 is postulated. [ABSTRACT FROM AUTHOR]

The time of arrival (ToA) and received signal strength (RSS) estimation errors are modelled based on channel measurements in a non‐line‐of‐sight indoor environment. It is found interesting that their errors are largely independent. Suboptimal hybrid ToA/RSS ranging estimators are derived in closed form based on the obtained error models, and shown to achieve near‐optimal performance. The performance of all the estimators improves as the bandwidth increases. [ABSTRACT FROM AUTHOR]

The article reports on the synthesis of functional diamines 3,3'-diaminochalcone and bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide. According to the authors, overall yields were pegged at 78 and 70 percent. The copolymides prepared exhibited high levels of solubility in organic solvents and thermal stability up to 450 degrees Celsius. They also report that copolymides that contain chalcone and phosphine oxide moieties in the main chain exhibited high levels of adhesiveness and photoreactivity.

Nine new monoterpene glycosides are isolated along with 18 known compounds from Paeonia suffruticosa Andrews. [ABSTRACT FROM AUTHOR]

In the title compound, C(21)H(28)N(2)O, the dihedral angle between the rings is 35.2 (2)°. A weak intra-molecular O-H⋯N hydrogen bond is observed between the O-H H atom and the imine N atom. In the crystal, mol-ecules are linked by additional inter-molecular N-H⋯O hydrogen bonding, resulting in a wave-like chain along the b-axis direction.