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A set of colour tuning K2Ba(MoO4)2: Dy3+/Eu3+ (KBM: Dy3+/Eu3+) phosphors were fabricated by solid-state method. The phase purity of as-prepared materials was validated by XRD and DRS analyses. The KBM: 0.03Dy3+ sample exhibits two major luminescence lines at 481 and 572 nm when excited by 351 nm light, corresponding to Dy3+ ions' typical transitions of 4F9/2 → 6HJ (J = 15/2, 13/2). By introducing Eu3+ ions into KBM: 0.03Dy3+ phosphor, the ET from Dy3+ to Eu3+ ions arises, leading to colour tuning from green via yellowish green to pink with changing Eu3+ ions' concentration, along with the lowest CCT of KBM: 0.03Dy3+/0.03Eu3+ sample. It can be verified by PLE and PL spectra analysis combined with the decay times of KBM: 0.03Dy3+/yEu3+ samples. The energy transfer mechanism is also expounded. Meanwhile, the emission intensities at 423 K still maintain 72.8% for Dy3+ ions and 91.2% for Eu3+ ions relative to 303 K of the KBM: 0.03Dy3+/0.03Eu3+ sample, displaying its brilliant thermal stability. All these results connote that KBM: Dy3+/Eu3+ phosphors are prospected to be used for the near-UV excited white light-emitting diodes. [ABSTRACT FROM AUTHOR]

Single-layer SrTiO 3 film and SiO 2 /SrTiO 3 composite film electroluminescence (EL) devices were fabricated on n-Si substrate though vacuum electron vapor deposition (EBVD) technique. The film layers in the device were analyzed using various detection methods to determine their microstructure and composition, and the EL properties of both types of devices were compared. EL experimental results show that both devices can emit white light visible to the naked eye when the forward bias is applied. Moreover luminescence intensity of SiO 2 /SrTiO 3 composite thin film devices is much higher than that of single-layer SrTiO 3 thin film devices. The EL spectrum analysis of the device samples shows that there are three luminescence peaks in both types of devices, and they are located in the blue, yellow and red regions. Three emission peaks of single-layer SrTiO 3 thin film devices are located at 460 nm (blue region), 580 nm (yellow region) and 685 nm (red region). Three luminescence peaks of SiO 2 /SrTiO 3 composite thin film devices are located at 460 nm (blue region), 585 nm (yellow region) and 716 nm (red region). In composite film devices, SiO 2 acts as an electron barrier layer, confining electrons to the SrTiO 3 film layer and increasing the chance for the electrons in the SrTiO 3 conduction band to participate in the composite luminescence. As a result, the blue peak emission intensity of the SrTiO 3 composite film device is significantly enhanced, while the overall white light emission intensity of the composite thin film device is greatly improved. Additionally, the color coordinates of SiO 2 /SrTiO 3 composite film device is closer to those of standard white light according to CIE standards. • The electroluminescence properties of single layer SrTiO 3 film and SiO 2 /SrTiO 3 composite film are prepared and compared. • composite film device not only effectively improves the luminance, but also has CIE color coordinates closer to standard white light.The SiO 2 /SrTiO 3 composite film device has higher brightness and CIE coordinates are closer to standard white light. • This study provides a way to develop white perovskite light-emitting diodes with small volume, low cost and no phosphor. [ABSTRACT FROM AUTHOR]

Two new flavonoids, bismilachinone ( 11 ) and smilachinin ( 14 ), were isolated from the leaves of Smilax china L. together with 14 known compounds. Their structures were elucidated using spectroscopic methods. The PTP1B, α-glucosidase, and DPP-IV inhibitory activities of compounds 1 – 16 were evaluated at the molecular level. Among them, compounds 4 , 7 , and 10 showed moderate DPP-IV inhibitory activities with IC 50 values of 20.81, 33.12, and 32.93 μM, respectively. Compounds 3 , 4 , 6 , 11 , 12 , and 16 showed strong PTP1B inhibitory activities, with respective IC 50 values of 7.62, 10.80, 0.92, 2.68, 9.77, and 24.17 μM compared with the IC 50 value for the positive control (ursolic acid: IC 50 = 1.21 μM). Compounds 2 – 7 , 11 , 12 , 15 , and 16 showed potent α -glucosidase inhibitory activities, with respective IC 50 values of 8.70, 81.66, 35.11, 35.92, 7.99, 26.28, 11.28, 62.68, 44.32, and 70.12 μM. The positive control, acarbose, displayed an IC 50 value of 175.84 μM. In the kinetic study for the PTP1B enzyme, compounds 6 , 11 , and 12 displayed competitive inhibition with K i values of 3.20, 8.56, and 5.86 μM, respectively. Compounds 3 , 4 , and 16 showed noncompetitive inhibition with K i values of 18.75, 5.95, and 22.86 μM, respectively. Molecular docking study for the competitive inhibitors ( 6 , 11 , and 12 ) radically corroborates the binding affinities and inhibition of PTP1B enzymes. These results indicated that the leaves of Smilax china L. may contain compounds with anti-diabetic activity. [ABSTRACT FROM AUTHOR]

Abstract: Four unusually fused polycyclic sesquiterpenoid dimers, chlorahololides C–F (1–4), were isolated from the whole plant of Chloranthus holostegius. Their structures and absolute configurations were established by spectroscopic methods, including 2D NMR and CD spectra. Chlorahololides C–F (1–4) exerted potent and selective inhibition on the delayed rectifier (I K) K+ current with the IC50 values of 3.6±10.1, 2.7±0.3, 27.5±5.1 and 57.5±6.1μM, respectively. [Copyright &y& Elsevier]

Surface-enhanced Raman scattering (SERS) of 4-mercaptopyridine (4-mpy) adsorbed on HNO3 etched silver foil, chemically deposited silver films (silver mirror) and silver colloids were measured. The SERS study has revealed that 4-mpy was adsorbed onto the three kinds of silver surfaces by a sulfur–silver bond with the plane of pyridine ring being normal to the silver substrates. The structure of 4-mpy adsorbed on the silver surfaces depends largely on the pH values of environment. When the pH values of the environment are changed, the structure of 4-mpy adsorbed on silver surfaces can easily be altered through a protonation or deprotonation reaction occurring on the N atom of the pyridine ring, and the modified structure shows unique characters on the SERS spectrum. Owing to the remarkable enhancement ability of SERS technique and characteristic spectrum of different species, a monolayer of 4-mpy assembled on a silver mirror holds potential as a H+ sensor for highly sensitive detection of the proton concentration in an aqueous solution. [ABSTRACT FROM AUTHOR]

(+)- and (-)-Tedanine [(+)-1 and (-)-1], a pair of new enantiomeric indolone alkaloids, along with nine compounds (2–10) were isolated from the marine sponge Tedania sp. The structures of (+)-1 and (-)-1 including absolute configurations were determined by spectroscopic analysis and quantum chemical calculation. Compounds (+)-1 and (-)-1 were the first examples of indolone alkaloids isolated from this genus. In addition, the cytotoxic and antibacterial activities of these compounds were also evaluated. [ABSTRACT FROM AUTHOR]

Two new alkaloids, spongimides A (1) and B (2), along with five known ones (3–7), were isolated from the marine sponge Spongia sp. The structures of 1 and 2 were determined by the spectroscopic methods (UV, IR, MS, and NMR) and X-ray diffraction analysis. Compounds 1, 3, and 4 were the first examples of 2,4-imidazolidinediones isolated from this genus. In addition, the cytotoxic and antibacterial activities of compounds 1 and 2 were also evaluated. [ABSTRACT FROM AUTHOR]

The phytochemical investigation on the fruits of Flueggea virosa resulted in the discovery of two new norsecurinine-derived alkaloid dimers, norsecurinamines A and B ( 1 and 2 ). Compound 1 is the first hetero-dimeric alkaloid possessing norsecurinine and donaxaridine units, and 2 represents the first example of NH -linked dimeric Securinega alkaloid. Their structures and absolute configuration were elucidated on the basis of extensive spectroscopic analysis as well as single-crystal X-ray diffraction method. A plausible biogenetic pathway of 1 was also proposed. [ABSTRACT FROM AUTHOR]

Five undescribed eremophilane-type sesquiterpenes, remophilanetriols E -I (1 – 5), along with seven known compounds (6 – 12) were isolated from the fresh roots of Rehmannia glutinosa. Their structures were characterized by extensive spectroscopic data analysis and their absolute configurations were determined by comparing their calculated electronic circular dichroism (ECD) spectra and experimental ECD spectra. The anti-pulmonary fibrosis activities of all compounds were evaluated in vitro by MTT methods, and compounds 2 , 8 , 10 , and 12 exhibited excellent anti-pulmonary fibrosis activities. In addition, compound 2 can reduce the levels of ROS and apoptosis in TGF-β1-induced BEAS-2B cells. [Display omitted] [ABSTRACT FROM AUTHOR]

Inhibitors of protein tyrosine phosphatase 1B (PTP1B) are promising agents for the treatment of type 2 diabetes and obesity. The bioactivity-guided isolation led to the separation of two new compounds, (±)-tradescantin ( 13 ) and tradescantoside ( 16 ), along with fourteen known compounds ( 1 – 12 , 14 , and 15 ) from the aerial parts of Tradescantia spathacea Sw. (Commelinaceae). Their chemical structures were elucidated by spectroscopic methods as well as by comparing with those reported in the literature. The isolated compounds ( 1 – 16 ) were then examined for their inhibitory activity toward PTP1B. The results indicated that compounds 2 , 6 , 8 , and 12 possessed potent inhibition with IC 50 values of 7.82 ± 0.79, 6.80 ± 0.89, 4.55 ± 0.92, and 6.38 ± 0.14 μM, respectively. Kinetic study of compounds 2 , 6 , 8 , 12 , 13 , and 16 was conducted and the structure–activity relationships of the isolated compounds ( 1 – 16 ) were also discussed herein. To the best of our knowledge, all the isolates were separated for the first time from this plant. [ABSTRACT FROM AUTHOR]

Abstract: Langmuir films of a side-chain ferroelectric liquid crystalline polysiloxane of 4-(10-undecen-1-oyloxy)-4′-(s)-2-methybutoxybiphonyl (P(III)) and its monomer 4-(10-undecen-1-oyloxy)-4′-(s)-2-methybutoxybiphonyl (M(III)) were transferred successfully at surface pressures of 11 and 8 mN m−1 onto solid substrates, respectively. The π–A isotherms of P(III) and M(III) have shown that they have different properties on the air/water interface. The monolayer film on the air/water interface of M(III) shows a clear orientation transition while that of P(III) does not. Infrared (IR) transmission and reflection–absorption spectra of Langmuir–Blodgett (LB) films of P(III) and M(III) indicate that the long axis of the chromophoric part of P(III) is almost perpendicular to the substrate surface while that of M(III) is tilted with respect to the substrate normal. The alkyl parts of both P(III) and M(III) are tilted considerably from the substrate normal. It also indicated from the IR spectra of the LB films that the liquid crystalline molecules of P(III) and M(III) are highly ordered and oriented in the monolayer and multilayer LB films. Temperature-dependent IR experiments show that the alkyl chains have anisotropic property in both P(III) and M(III). This may be due to the influence from the chiral groups of the molecules rather than from the substrates, and the side chains of P(III) play an important role in enhancing the anisotropic property. [Copyright &y& Elsevier]

The structure and vibrational frequencies of the chiral antiferroelectric liquid-crystal molecule, 4-(1-methyheptyloxycarbonyl) phenyl-4-(4′-octyloxy) benzoate (MHOCPOOB), have been calculated using the density-functional theory (DFT) with the Becke-3 Lee–Yang–Parr/6-31G(d,p) level. The observed vibrational spectra have been resolved and assigned in detail by comparison to the computed values. The results indicate that the computed and observed spectra are in good agreement with each other. The stable molecular structure obtained with the DFT theory shows that the two hydrocarbon chains are all-trans zigzag conformer and nearly perpendicular to each other. The orientation of the mesogen part and the hydrocarbon chains for MHOCPOOB in the Sm–CA* phase are investigated by employing the polarization-angle-dependent infrared spectra in the electric-field induced and the two-dimensional correlation spectroscopy. After combining the experimental and theoretical results, it can be concluded that the azimuth of the achiral and chiral chains is opposite to each other, the orientation of the achiral chain is almost the same direction as the mesogen core, and the orientation of the chiral chain is nearly perpendicular to the mesogen part. The achiral and chiral CH2 chains are both a probable all-trans zigzag conformer. [ABSTRACT FROM AUTHOR]

A novel valerenane sesquiterpenoid sinulaspirolactam A (1), together with five known compounds, was isolated from the soft coral Sinularia sp. Their structures were determined by spectroscopic analyses. The absolute configuration of 1 was established by ECD calculation. Compound 1 was the first example of valerenane sesquiterpenoid bearing an aza-spiro[4.5] ring moiety, the plausible biogenetic pathway of which was proposed. Cytotoxic activities of these compounds were also evaluated. [ABSTRACT FROM AUTHOR]

Glyphosate is one of the most commonly-used and non-selective herbicides in agriculture, which may directly pollute the environment and threaten human health. A simple and effective approach to assessment of its damage to the natural environment is thus quite necessary. However, traditional chromatography-based detection methods usually suffer from complex pretreatment procedures. Herein, we propose a simple and sensitive method for the determination of glyphosate by combining ninhydrin reaction and surface-enhanced Raman scattering (SERS) spectroscopy. The product (purple color dye, PD) of the ninhydrin reaction is found to SERS-active and directly correlate with the glyphosate concentration. The limit of detection of the proposed method for glyphosate is as low as 1.43 × 10 − 8 mol·L − 1 with a relatively wider linear concentration range (1.0 × 10 − 7 -1.0 × 10 − 4 mol·L − 1 ), which demonstrates its great potential in rapid, highly sensitive concentration determination of glyphosate in practical applications for safety assessment of food and environment. [ABSTRACT FROM AUTHOR]

Astract Two new C 18 -diterpenoid alkaloids, sinomontadine ( 1 ) and sinomontanine N ( 2 ), were isolated from Aconitum sinomontanum . Their structures were determined by spectroscopic methods and X-ray crystallographic analysis. Sinomontadine ( 1 ) features an unprecedented skeleton containing a seven-membered ring (A-ring), while sinomontanine N ( 2 ) is chlorinated. A plausible biogenetic pathway for 1 was proposed. [ABSTRACT FROM AUTHOR]

Two new limonoids, chukrasone A (1) incorporating a highly rearranged A/B ring system and chukrasone B (2) possessing the first 16,19-dinor limonoid backbone with an extended C3 unit at C-15, were isolated from Chukrasia tabularis. Their structures were characterized on the basis of detailed spectroscopic analysis. Compounds 1and 2exhibited potential inhibition of the delayed rectifier (IK) K+current. [ABSTRACT FROM AUTHOR]

Abstract: Using an electroless replacement deposition method, large-area superhydrophobic metal substrate could be obtained. The superhydrophobic surfaces were prepared via a replacement reaction between copper substrate and HAuCl4 solution. The roughness of the copper substrate increased much after the replacement reaction. X-ray powder diffraction (XRD) pattern and energy dispersive X-ray (EDX) spectroscopy have proved that gold, CuCl and Cu2O formed on the surface of copper substrate after the replacement reaction. The surface showed remarkable superhydrophobic properties with a contact angle higher than 150 degrees without any modification with a self-assembled monolayer (SAM) of long chain thiol or perfluoro molecules. [Copyright &y& Elsevier]

Abstract: In this paper, triangular and hexagonal silver nanoplates were prepared on the surface of quartz substrate using photoreduction of silver ions in the presence of silver seeds. The obtained silver nanoplates were characterized by atomic force microscopy and UV–vis spectroscopy. It was found that the silver seeds played an important role in the formation of triangular and hexagonal silver nanoplates. By varying the irradiation time, nanoplates with different sizes and shapes could be obtained. The growth mechanism for triangular and hexagonal nanoplates prepared on quartz substrate was discussed. [Copyright &y& Elsevier]

Abstract: In this article, we report a simple wet-chemical method to prepare silver microflowers and large spherical particles. The formation of the two different microstructures of silver is based on the reduction of AgNO3 by para-phenylenediamine in aqueous medium at room temperature. The controlling of the silver microstructures can be achieved only by adjusting the concentration of the reactants. It is found that the two different silver microstructures display opposite wetting properties. Large spherical silver particles exhibit superhydrophilic properties with a contact angle (CA) of close to 0°, microflower-like silver particles exhibit highly hydrophobic properties with CA about 132°. X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and UV–vis spectra are used to characterize the chemical structure of the obtained products. [Copyright &y& Elsevier]

Abstract: Ga-doped zinc oxide (ZnO:Ga) transparent conductive films with highly (002)-preferred orientation were deposited on glass substrates by DC reactive magnetron sputtering method in Ar + O2 ambience with different Ar/O2 ratios. The structural, electrical, and optical properties were investigated by X-ray diffraction, Hall measurement, and optical transmission spectroscopy. The resistivity and optical transmittance of the ZnO:Ga thin films are of the order of 10−4 Ω cm and over 85%, respectively. The lowest electrical resistivity of the film is found to be about 3.58×10−4 Ω cm. The influences of Ar/O2 gas ratios on the resistivity, Hall mobility, and carrier concentration were analyzed. [Copyright &y& Elsevier]

Abstract: The molecular geometry and vibrational frequencies of 4,4′-azopyridine (AZPY) were calculated using the density functional theory (DFT) methods. Fourier transform infrared (FTIR), fourier transform Raman (FT-Raman) and near-infrared surface-enhanced Raman scattering (NIR-SERS) spectra of AZPY on the silver foil substrate have been recorded. On the basis of the computed results, FTIR, FT-Raman and NIR-SERS bands were assigned. It is shown that the calculated and observed frequencies are in good agreement with each other for FTIR and FT-Raman spectra. Surface selection rules derived from the electromagnetic enhancement model were employed to infer the orientations of AZPY on the silver foil substrate surface. [Copyright &y& Elsevier]

Abstract: A simple method of the reduction of AgNO3 by copper foil in aqueous medium was used to prepare silver dendrites, which can be used as a novel good reproducible surface enhanced Raman scattering (SERS) active substrate. The SERS spectra of 4-pyridinethiol on this novel substrate reflected the different SERS activities on the minuteness and strong Ag dendrites. The electromagnetic coupling enhancement and chemical enhancement mechanisms are used to explain the SERS effect. [Copyright &y& Elsevier]

Abstract: N doped and Al–N codoped ZnO films were prepared by dc reactive magnetron sputtering with a series of metal–Zn targets having different Al contents. The best p-type electrical properties of codoped ZnO, such as carrier concentration of 2.52×1017 cm−3, resistivity of 28.3Ωcm can be realized by using 0.4at.% Al target. Results of Hall effect and X-ray photoelectron spectroscopy (XPS) measurements confirm that the presence of Al indeed facilitates the incorporation of N through formation Aln codoped ZnO. Finally, a new judgement for codoping effect in ZnO is proposed tentatively: the best codoping effect can be realized when the codoped ZnO films possess a closest (002) d-spacing value to the nominally undoped ZnO. [Copyright &y& Elsevier]

Abstract: Two single-bond conformational isomers (all-trans and trans–cis) of 1,4-bis[2-(4-pyridyl) ethenyl]-benzene (BPENB) have been studied using density functional theory (DFT) methods. The Fourier transform infrared (FTIR), Fourier transform Raman spectra (FT-Raman) and surface-enhanced Raman scattering (SERS) spectra of BPENB on new Ag substrates at different concentrations have been recorded. All FTIR, FT-Raman and SERS bands were assigned on the basis of the B3LYP/6-31++G(d,p) method. Our calculated vibrational frequencies are in good agreement with experimental wavenumbers. Surface selection rules derived from the electromagnetic enhancement model were employed to infer BPENB orientations on a silver substrate surface at different concentrations. [Copyright &y& Elsevier]

Water-induced changes in the morphology and optical properties of an ultrathin Ag film (3 nm thickness) have been studied by use of ultraviolet–visible (UV–Vis) spectroscopy, atomic force microscopy (AFM) and surface-enhanced Raman scattering (SERS) spectroscopy. A confocal micrograph shows that infinite regular Ag rings with almost uniform size (4 μm) emerge on the film surface after the ultrathin Ag film was immersed into water. The AFM measurement further confirms that the Ag rings consist of some metal holes with pillared edges. The UV–Vis spectrum shows that an absorption band at 486 nm of the Ag film after the immersion in water (I-Ag film) blue shifts by 66 nm with a significant decrease in absorbance, which is attributed to the macroscopic loss of some Ag atoms and the change in the morphology of the Ag film. The polarized UV–Vis spectra show that a band at 421 nm due to the normal component of the plasmon oscillation blue shifts after immersing the ultrathin Ag film into water. This band is found to be strongly angle-dependent for p-polarized light, indicating that the optical properties of the ultrathin Ag film are changed. The I-Ag film is SERS-active, and the SERS enhancement depends on different active sites on the film surface. Furthermore, it seems that the orientation of an adsorbate is related to the morphology of the I-Ag film. [Copyright &y& Elsevier]

Polarization-dependent infrared spectra of an antiferroelectric liquid crystal in the phase were measured at 60°C, for investigation of the relative orientation of the terminal alkyl chain and mesogen. The polarization angle-dependent infrared spectra obtained were analysed by two-dimensional (2D) correlation spectroscopy. The orientation of the mesogen segment and the alkyl chains in the phase is similar to that in the SmC* phase. Four new CH 3 and CH 2 stretching modes were observed from the 2D correlation spectra. From these we can clearly separate the vibrational mode for two hydrocarbon chains and conclude that the orientations of the two chains are different. The C=O group adjacent to the chiral segment is also separated by 2D correlation spectra into two bands, which may arise from either the C=O group hydrogen-bonded with the phenyl ring, or from another rotational conformation of the molecule. [ABSTRACT FROM AUTHOR]

A self-assembled film of ruthenium phthalocyanine (RuPc) fabricated on a silver substrate pre-modified with a monolayer of 4-mercaptopyridine (PySH) or 1,4-bis[2-(4-pyridyl)ethenyl]-benzene (BPENB) was studied by ultraviolet-visible (UV-Vis) and surface enhanced Raman scattering (SERS) spectroscopy. PySH or BPENB was used as a ligand to link RuPc since they not only modify the silver substrate, but also deliver a pyridyl group pointing out from the silver surface. Therefore, we can explore the relationship between the structure and orientation of metallophthalocyanine and the substrate modified by the two kinds of organic-monolayers with the different conjugates and molecular lengths. UV-Vis bands due to the organic-monolayer (PySH or BPENB) modified silver films shift to longer wavelengths and a new band arising from the metallophthlocyanine appears, suggesting the binding of RuPc to PySH/BPENB, as well as the interaction between the marcocycle of RuPc and the ring of PySH/BPENB. Vibrational bands arising from both the RuPc and PySH/BPENB moieties appear clearly in the SERS spectra of the RuPc–PySH/BPENB composite films, indicating that RuPc is successfully assembled on the top of PySH/BPENB film. The shifts and relative intensity changes of bands due to PySH or BPENB in the SERS spectra imply the binding of the metallophthalocyanine to the pyridyl group in the composite films. Furthermore, the comparison of the SERS spectra revealed that the orientations of PySH and BPENB in the two kinds of composite films are different; the BPENB moiety in the RuPc–BPENB composite film is more perpendicular to the silver surface compared with the PySH moiety in the RuPc–PySH composite film. [Copyright &y& Elsevier]

A surface plasmon resonance (SPR)-surface enhanced Raman scattering (SERS) microspectrometer was designed to obtain the incident angle dependence of SERS signals excited by the evanescent field. By simultaneous measurement of the SERS and SPR spectra of analytes, the highest SERS signal intensities were found to appear at the vicinity of the resonance angle. The enhancement factor was about 2.0×106. The simulated angle of the maximal SERS intensity based on Fresnel equation was found to be in good agreement with the experimental results. The SERS and SPR spectra captured simultaneously not only directly confirm the correlation between the SERS and SPR but also present a potential technique for obtaining the structure information about the analytes in molecule level with recording their SPR curves. [ABSTRACT FROM AUTHOR]