Converting an Almost Noncytotoxic Ru(II) Complex with Photolabile Ligands into a Highly Efficient PACT Agent

Ru(II) complexes with weak ligand fields may undergo light-induced ligand dissociation, and the resulted Ru(II) aqua complexes may bind with biomolecules such as DNA, showing potential as photoactivated chemotherapy (PACT) agents. However, Ru(II) complexes with efficient PACT activity are still rare. Some Ru(II) complexes exhibit efficient photoinduced ligand dissociation but poor cytotoxicity. It is speculated that the low nuclear accumulation levels may account for their low PACT efficacy. In order to confirm this hypothesis, the almost noncytotoxic [Ru(7-OCH₃-dppz)(4-OCH₃-py)₄](PF₆)₂ (Ru1) is loaded on nucleus-targeted C₅N₂ nanoparticles (NPs). Compared with the free Ru1, Ru1–C₅N₂ NPs exhibit significantly increased cellular uptake and nuclear accumulation. Therefore, Ru1–C₅N₂ NPs show efficient PACT activity toward various cancer cell lines (including cisplatin-resistant one) with half maximal inhibitory concentration (IC₅₀) values of 0.18 × 10⁻⁶–0.29 × 10⁻⁶ m and phototoxicity index (IC₅₀^dark/IC₅₀^light) values above 137 under both normoxic and hypoxic conditions. Moreover, Ru1–C₅N₂ NPs also exhibit efficient PACT activity toward cisplatin-resistant 3D multicellular tumor spheroids upon two-photon irradiation (800 nm). The same strategy is also feasible to greatly improve the PACT activity of [Ru(7-OCH₃-dppz)(py)₄]²⁺, which itself only has a medium effect. The results may provide new sights for developing efficient Ru(II) PACT agents.     

A Dual Component Catalytic System Composed of Non‐Noble Metal Oxides for Li–O2 Batteries with Enhanced Cyclability

One of the great challenges in the development of lithium–oxygen batteries (Li–O₂ batteries) is to synthesize cost‐effective and efficient electrocatalysts to overcome several issues such as high charge overpotential and poor cycle life. Here, an efficient method is reported to fabricate a dual component electrocatalyst made of MnO₂ nanoparticles supported on 1D Co₃O₄ nanorods (MnO₂–Co₃O₄), and its electrochemical behavior as a non‐noble metal cathode catalyst is demonstrated in Li–O₂ batteries. It is found that the as‐made MnO₂–Co₃O₄ catalyst exhibits an enhanced electrochemical performance, such as increased specific capacity (increase to 4023 mA h g^?1 from 2993 mA h g^?1), low charge overpotential (reduce 350 mV), high rate performance, and superior cyclability up to 150 cycles. The excellent electrochemical performance is attributed to the synergistic effects of the dual component catalytic system.     

Facile Synthesis of Manganese Tellurite Nanoparticles for Magnetic Resonance Imaging-Guided Photothermal Therapy

In this study, manganese tellurite (MnTeO₃) nanoparticles are developed as theranostic agents for magnetic resonance imaging (MRI)-guided photothermal therapy of tumor. MnTeO₃ nanoparticles are synthesized via a simple one-step method. The as-synthesized MnTeO₃ nanoparticles with uniform size show good biocompatibility. In particular, MnTeO₃ nanoparticles exhibit a high photothermal conversion efficiency (η = 26.3%), which is higher than that of gold nanorods. Moreover, MnTeO₃ nanoparticles also have high MRI performance. The longitudinal relaxivity (r₁) value of MnTeO₃ nanoparticles is determined to be 8.08 ± 0.2 mm ⁻¹ s⁻¹, which is higher than that of clinically approved T₁-contrast agents Gd-DTPA (4.49 ± 0.1 mm ⁻¹ s⁻¹). The subsequent MnTeO₃ nanoparticles-mediated photothermal therapy displays a highly efficient ablation of tumor cells both in vitro and in vivo with negligible toxicity. It is demonstrated that MnTeO₃ nanoparticles can serve as promising theranostic agents with great potentials for MRI-guided photothermal therapy.     

基于新型电荷生成层的P-i-N结构白色有机叠层电致发光器件

采用2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP): 5 wt.% cesium carbonate(Cs₂CO₃)和N, N'-Bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine(NPB): 20 wt.% molybdenum oxide(MoO₃)分别作为器件的电子注入层和空穴注入层,研究了N型和P-i-N结构有机电致发光器件的载流子传输特性.载流子传输层中BCP: Cs₂CO₃和NPB:MoO₃的引入有效增强了载流子注入能力,从而降低了器件的驱动电压.基于新型电荷生成层BCP: 5 wt.% Cs₂CO₃/ NPB: 20 wt.% MoO₃制备了色稳定、高效率P-i-N结构有机叠层器件.与单元器件相比,引入新电荷生成层有机叠层器件的最大电流效率增大了2.5倍,表明该电荷生成层可以有效地将电子和空穴分别注入到相邻发光单元中.采用该电荷生成层制备了P-i-N结构白色有机叠层器件,器件的上下发光单元分别为橙光和蓝光发射.当发光亮度从500增加到5 000 cd/m²时,器件的色坐标稳定在(0.33, 0.29)附近,接近白光等能点.利用单色发光单元堆叠制备白色有机叠层器件的方法为实现色稳定、高效率的白色有机电致发光器件提供了一种有效的途径.     

SF2自由基3d,5s里德伯态的实验确认

利用自行研制的脉冲直流放电装置产生SF₂自由基，结合共振增强多光子电离(REMPI)技术，研究了27—294nm范围内SF₂自由基(2+1)REMPI激发谱，获得了SF₂自由基3d,5s里德伯态相应的带源及被激活的对称伸缩振动模的振动频率，并估算了这些态的量子亏损值． 关键词：     

Paramagnetic liposomes as MRI contrast agents: influence of liposomal physicochemical properties on the in vitro relaxivity

The in vitro contrast efficacy of liposome encapsulated gadolinium-[10-(2-hydroxypropyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid] (GdHPDO3A) has been assessed by relaxometry. The internal concentrations were 150 and 250 mM Gd. Two types of liposome compositions were investigated: a phospholipid blend consisting of both hydrogenated phosphatidylcholine (HPC) and phosphatidylserine (HPS) with a gel-to-liquid crystalline phase transition temperature (T_m) of 50°C, and a mixture of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) with a T_m of 41°C. The investigated liposome size range was 70–400 nm. The T₁ and T₂ relaxivities (r₁ and r₂) of liposome encapsulated GdHPDO3A were significantly reduced at 37°C and 0.47 T, compared to those of non-liposomal metal chelate, due to an exchange limitation of the dipolar relaxation process. The highest relaxivity values were obtained for the DPPC/DPPG liposomes, and were attributed to a higher liposome water permeability and to a more efficient water exchange across the membrane. A reduction in liposome size increased the r₁, confirming the exchange limited dipolar relaxation. The increased r₁ with increasing temperature demonstrated the prerequisite of rapid water exchange between the interior and exterior of the liposome for efficient dipolar relaxation enhancement. Susceptibility effects were present in the liposome systems as the r₂/r₁ ratio increased with increasing liposome size and internal Gd concentration. In summary, the current work has shown the influence of key physicochemical properties, such as liposome size, membrane composition and permeability, on the in vitro relaxivity of liposome encapsulated GdHPDO3A.     

Synthesis, characterization and spectroscopic investigation of new tetrakis(acetylacetonato)thulate(III) complexes containing alkaline metals as countercations

In this work a series of tetrakis complexes C[Tm(acac)₄], where C⁺=Li⁺, Na⁺ and K⁺ countercations and acac=acetylacetonate ligand, were synthesized and characterized for photoluminescence investigation. The relevant aspect is that these complexes are water-free in the first coordination sphere. The emission spectra of the tetrakis Tm³⁺-complexes present narrow bands characteristic of the ¹G₄→³H₆ (479 nm), ¹G₄→³F₄ (650 nm) and ¹G₄→³H₅ (779 nm) transitions of the Tm³⁺ ion, with the blue emission color at 479 nm as the most prominent one. The lifetime values (τ) of the emitting ¹G₄ level of the C[Tm(acac)₄] complexes were 344, 360 and 400 ns for the Li⁺, Na⁺ and K⁺ countercations, respectively, showing an increasing linear behavior versus the ionic radius of the alkaline ion. An efficient intramolecular energy transfer process from the triplet state (T) of the ligands to the emitting ¹G₄ state of the Tm³⁺ ion is observed. This fact, together with the absence of water molecules in first coordination sphere, allows these tetrakis Tm³⁺-complexes to act as efficient blue light conversion molecular devices.     

Energy transfer from a polymer host to a europium complex in light-emitting diodes

Energy transfer leading to electroluminescence of a lanthanide complex, Eu(Fod)₃MK (Fod=heptafluoro-dimethyl-octanedionate, MK=4, 4′-bis(N,N-dimethylaminobenzophenone) doped into PVK host is investigated. The optical properties of pure Eu(Fod)₃MK and its doping in PVK show that the PVK host can efficiently transfer energy to europium ions through a co-ligand of MK due to good spectrally overlap. Light-emitting diodes (LED) consisting of PVK doped with 1-5 wt% of Eu(Fod)₃MK also demonstrates this energy transfer. Organolanthanide complexes doped into a wide-gap conducting polymers would lead to efficient and pure red organic LEDs to solve the full colour conjugated polymer displays.     

Enhancement of 1.35 μm fluorescence lifetime of Cr<Superscript>4+</Superscript>-doped YAG crystal by Ytterbium codoping

The 1.35 μm fluorescence lifetime from Cr⁴⁺-doped YAG crystal was strongly enhanced by doping Yb ions. We demonstrate that Yb ions act as efficient sensitizers of the ³ B ₂ (³ T ₂) → ³ B ₁(³ A ₂) emission of Cr⁴⁺ ions. The lifetime enhancement factor depending on Yb concentration was studied. Our results show that the crystal could be used in microchip laser and has a promising potential as an efficient source with the near infrared emission.     

Time‐resolved spectroscopic and density functional theory investigation of the photochemistry of suprofen

The photochemistry of suprofen (SPF) was investigated by femtosecond transient absorption (fs‐TA), resonance Raman (RR) and nanosecond time‐resolved resonance Raman (ns‐TR³) spectroscopic methods to gain additional information so as to better elucidate the possible photochemical reaction mechanism of suprofen in several different solvents. In neat acetonitrile (MeCN), the fs‐TA and ns‐TR³ experimental data indicated that the lowest lying excited singlet state S₁ (nπ*) underwent an efficient intersystem crossing process (ISC) to the excited triplet state T₃ (ππ*), followed by an internal conversion (IC) process to T₁ (ππ*). In the aqueous solution, a triplet biradical species (³ETK‐1) was obtained as the product of a decarboxylation process from triplet suprofen anion (³SPF⁻) and the reaction rate of the decarboxylation process was determined by the concentration of H₂O. A protonation process for ³ETK‐1 leads to formation of a neutral species (³ETK‐3) that was directly observed by ns‐TR³ spectra, then this ³ETK‐3 species decayed via ISC process to generate final product. Copyright © 2014 John Wiley & Sons, Ltd.     

Spectral-kinetic characteristics of Pr luminescence in LiLuF4 host upon excitation in the UV-VUV range

Spectral-kinetic study of Pr³⁺ luminescence has been performed for LiLuF₄:Pr(0.1 mol%) single crystal upon the excitation within 5-12 eV range at T=8 K. The fine-structure of Pr³⁺ 4f ²→4f 5d excitation spectra is shown for LiLuF₄:Pr(0.1 mol%) to be affected by the efficient absorption transitions of Pr³⁺ ions into 4f 5d involving 4f ¹ core in the ground state. Favourable conditions have been revealed in LiLuF₄:Pr(0.1 mol%) for the transformation of UV-VUV excitation quanta into the visible range. Lightly doped LiLuF₄:Pr crystals are considered as the promising luminescent materials possessing the efficient Pr³⁺³P₀ visible emission upon UV-VUV excitation. The mechanism of energy transfer between Lu³⁺ host ion and Pr³⁺ impurity is discussed.     

Wet chemical etching method for BST thin films annealed at high temperature

As a traditional etchant, pure buffered hydrofluoric acid (BHF), does not possess the ability to etch BST thin films annealed at high temperature, even though it works greatly on as-deposited Ba_0.5Sr_0.5TiO₃ (BST) films. In this paper, we developed an etchant by mixing BHF and strong acid (HNO₃, HCl, H₂SO₄ and H₃PO₄) and use it successfully on BST films annealed with high temperature. The experimental results show that a 1-8 wt% of strong acid acts as an efficient catalyst and the etching speed is significantly improved. The etched BST films show little distortions and smooth etching edges were recorded.     

Relative Study of Luminescent Properties with Judd-Ofelt Characterization in Trivalent Europium Complexes Comprising ethyl-(4-fluorobenzoyl) Acetate

Five new europium(III) complexes Eu(p-EFBA)₃.(H₂O)₂ (C1), Eu(p-EFBA)₃.neo (C2), Eu(p-EFBA)₃.batho (C3), Eu(p-EFBA)₃.phen (C4), Eu(p-EFBA)₃.bipy (C5) have been synthesized by using ethyl-(4-fluorobenzoyl) acetate (p-EFBA) as β-ketoester ligand and neocuproine (neo), bathophenanthroline (batho), 1,10-phenanthroline (phen) and 2,2-bipyridyl (bipy) as ancillary ligands. The synthesized complexes C1-C5 were characterized by elemental analysis, nuclear magnetic resonance spectroscopy (¹H-NMR), infrared (IR) spectroscopy, thermogravimetric analysis (TG/DTG), UV-visible and photoluminescence (PL) spectroscopy. The relative study of luminescence spectra of complexes with the previously reported complexes of isomeric ligand (ortho and meta substituted ligand) indicate the higher luminescence properties of complexes as an effect of fluorine position on β-ketoester ligand. The para substituted ligand shows a remarkable effect on quantum efficiencies and Judd-Ofelt intensity parameters (Ω_2, Ω₄) of the complexes. The higher value of intensity parameter Ω₂ associated with hypersensitive ⁵D₀ → ⁷F₂ transition of europium(III) ion revealing highly polarizable ligand field. The purposed energy transfer mechanism of complexes indicates the efficient energy transfer in complexes.     

Hydrophilic Cu3BiS3 Nanoparticles for Computed Tomography Imaging and Photothermal Therapy

Hydrophilic Cu₃BiS₃ nanoparticles (NPs) have been prepared using the thermal decomposition of precursor complexes in oily‐mixed solvent followed by coating the produced Cu₃BiS₃ NPs with polyvinylpyrrolidone (PVP). The resulting Cu₃BiS₃/PVP NPs remain stable in aqueous solutions over a long period of time, and meanwhile, they show low in vitro cytotoxicity and negligible toxicity to mice in vivo. Cu₃BiS₃/PVP NPs could operate as an efficient dual‐modal contrast agent to simultaneously enhance X‐ray computed tomography imaging and photothermal imaging of tumor model in vivo. Moreover, highly efficient ablation of cancer cells both in vitro and in vivo has been successfully achieved by combining Cu₃BiS₃/PVP NPs with near‐infrared (NIR) laser irradiation. All of the positive results in this study highlight that Cu₃BiS₃/PVP NPs could serve as a promising platform for cancer diagnosis and therapy.     

A versatile sonication-assisted deposition–reduction method for preparing supported metal catalysts for catalytic applications

This work aims to develop a rapid and efficient strategy for preparing supported metal catalysts for catalytic applications. The sonication-assisted reduction–precipitation method was employed to prepare the heterogeneous mono- and bi-metallic catalysts for photocatalytic degradation of methyl orange (MO) and preferential oxidation (PROX) of CO in H₂-rich gas. In general, there are three advantages for the sonication-assisted method as compared with the conventional methods, including high dispersion of metal nanoparticles on the catalyst support, the much higher deposition efficiency (DE) than those of the deposition–precipitation (DP) and co-precipitation (CP) methods, and the very fast preparation, which only lasts 10–20 s for the deposition. In the AuPd/TiO₂ catalysts series, the AuPd(3:1)/TiO₂ catalyst is the most active for MO photocatalytic degradation; while for PROX reaction, Ru/TiO₂, Au–Cu/SBA-15 and Pt/γ-Al₂O₃ catalysts are very active, and the last one showed high stability in the lifetime test. The structural characterization revealed that in the AuPd(3:1)/TiO₂ catalyst, Au–Pd alloy particles were formed and a high percentage of Au atoms was located at the surface. Therefore, this sonication-assisted method is efficient and rapid in the preparation of supported metal catalysts with obvious structural characteristics for various catalytic applications.     

Inter- and intraconfigurational optical transitions of the Pr ion for application in lighting and scintillator technologies

In this paper, a review of the application of the Pr³⁺ inter- and intraconfigurational optical transitions in lighting and scintillator technologies is presented. The possibility of generating more than one visible photon for each incident ultraviolet photon can be realized with the Pr³⁺ intraconfigurational emission emanating from the Pr³⁺¹S₀ state. The development of such materials can significantly improve the overall energy conversion of fluorescent lamps. Scintillators based on the intraconfigurational optical transitions emanating from the Pr³⁺³P₀ state has lead to the development and commercialization of the Gd₂O₂S:Pr³⁺ scintillator for application in computed tomography (CT). The development of fast scintillators for positron emission tomography (PET) and security applications can be realized with the efficient Pr³⁺ interconfigurational transitions (4f¹5d¹→4f²) in a solid.     

Pulsed laser deposition of lysozyme: the dependence on shot numbers and the angular distribution

An efficient near-infrared (NIR) quantum cutting (QC) by converting ultraviolet into NIR via cooperative downconversion (DC) for the (Nd³⁺, Yb³⁺) couple in CaWO₄ is studied since efficient two-step energy transfer occurs from the ⁴G_9/2 level of Nd³⁺ to two neighboring Yb³⁺:²F_5/2 level. The authors have analyzed the measured luminescence spectra and decay lifetimes for different Yb³⁺ concentrations and proposed a mechanism to rationalize the DC effect. The maximum quantum efficiency (QE) of Nd³⁺ is up to 164.03 %. Application of the broadband NIR-QC phosphors might enhance the performance of silicon-based solar cells.     

Single line high efficiency tunable fir generation by resonant four-wave mixing in CH3 pumped by a multiatmosphere tunable CO2 laser

By pumping CH₃F with a high pressure tunable TE-CO₂ laser, the resonant four-wave mixing process (RFWM) generates a very efficient tunable single line FIR emission at the Raman frequency. This result is strictly related to the spectroscopic structure of the CH₃F molecule. By means of this process, a tunable FIR emission on a 0.1 cm^–1 bandwidth 150 kW (8 mJ) single line, is obtained which can be used for many FIR multiphoton applications.     

Scheibe-aggregates of Pseudoisocyanine in solution and in molecular monolayers

A new working molecule 1,1,1,3,3,3-hexafluoro-2-(trifluoromethyl)-propane-2-t (CF₃)₃CT, is reported for the isotope separation of tritium by TEA CO₂-laser-induced multiphoton dissociation (MPD). Selective and efficient dissociation of (CF₃)₃CT was observed by irradiation at about 980 cm^–1 where (CF₃)₃CH was nearly transparent. The critical fluence for dissociation of (CF₃)₃CT at 10R(28) 980.9 cm^–1 was estimated to be as low as 4.6 J/cm², which is the lowest of the tritiated halocarbons that we have ever reported. A detailed study was made of the pressure dependence of the dissociation rate constants for (CF₃)₃CT and (CF₃)₃CH to clarify the collisional effects in their MPD. The hydrogen isotope exchange between (CF₃)₃CH and HTO was found to be extremely rapid, which is advantageous in the practical laser separation cycle for tritium removal from water.     

Near infrared fluorescence and energy transfer in Ce/Nd Co-doped CaxSr1−xS

Novel near infrared (NIR) phosphors Ca_xSr_1−xS:Ce³⁺,Nd³⁺ were synthesized by a solid state reaction. The NIR emission was realized through an efficient absorption by the allowed 4f-5d transition of Ce³⁺ and efficient energy transfer to Nd³⁺ via well-matched energy levels. Ce³⁺ and Nd³⁺ content in CaS/SrS was optimized. It was found that CaS:Ce³⁺,Nd³⁺ gave much stronger NIR emission than that of SrS:Ce³⁺,Nd³⁺. Further studies on Ca_xSr_1−xS:Ce³⁺,Nd³⁺ indicated that both visible emission of Ce³⁺ and NIR emission of Nd³⁺ were observably affected by Ca/Sr ratio. The energy transfer efficiency, which can be estimated from fluorescence lifetime of Ce³⁺, increased from 52% to 74% for the Ca_xSr_1−xS:Ce³⁺,Nd³⁺ (x=0 to 1) series, accompanied with a shift of maximal emission wavelength of Ce³⁺ from 482 to 505 nm. The results showed that overlap between emission spectrum of Ce³⁺ and excitation spectrum of Nd³⁺ plays an important role in the energy transfer efficiency, and Ce³⁺ emitting in green or blue-greenish region sensitized the Nd³⁺ NIR fluorescence emission more efficiently than that in blue region.