We report on the growth, structure, and polarized spectroscopy of a novel promising laser crystal, erbium-doped magnesium monotungstate, Er3+:MgWO4. 1.01 t.% Er3+:MgWO4 was grown by the Top-Seeded ...Solution Growth method using Na2WO4 as a solvent. The crystal structure was refined by the Rietveld method. Er3+:MgWO4 belongs to the monoclinic class (sp. gr. P2/c, wolframite-type structure, lattice parameters: a = 4.6939(6) Å, b = 5.6747(4) Å, c = 4.9316(6) Å and β = 90.7858(4) Å. The transition intensities for Er3+ ions were determined using the Judd-Ofelt theory accounting for an intermediate configuration interaction (ICI). Er3+ ions in MgWO4 exhibit intense, strongly polarized and broad absorption and emission bands owing to their accommodation in distorted low-symmetry sites (C2). The stimulated-emission cross-section for the 4I13/2 → 4I15/2 transition is 0.31×10−20 cm2 at 1637 nm (light polarization: E || b). The radiative lifetime of the 4I13/2 state is 4.85 ± 0.05 ms. The multiphonon non-radiative relaxation for Er3+ excited multiplets is quantified. Er3+ ions in MgWO4 feature large Stark splitting of the ground-state, ΔE(4I15/2) = 435 cm-1. Er3+:MgWO4 is attractive for low-threshold lasers at ∼1.64 µm.
We report on the development of a novel laser crystal with broadband emission properties at ∼2 µm – a Tm3+,Li+-codoped calcium tantalum gallium garnet (Tm:CLTGG). The crystal is grown by the ...Czochralski method. Its structure (cubic, sp. gr. ð¼ð'3ð'', a = 12.5158(0) Å) is refined by the Rietveld method. Tm:CLTGG exhibits a relatively high thermal conductivity of 4.33 Wm-1K-1. Raman spectroscopy confirms a weak concentration of vacancies due to the charge compensation provided by Li+ codoping. The transition probabilities of Tm3+ ions are determined using the modified Judd-Ofelt theory yielding the intensity parameters Ω2 = 5.185, Ω4 = 0.650, Ω6 = 1.068 10−20 cm2 and α = 0.171 10−4 cm. The crystal-field splitting of the Tm3+ multiplets is revealed at 10 K. The first diode-pumped Tm:CLTGG laser generates 1.08 W at ∼2 µm with a slope efficiency of 23.8%. The Tm3+ ions in CLTGG exhibit significant inhomogeneous spectral broadening due to the structure disorder (a random distribution of Ta5+ and Ga3+ cations over octahedral and tetrahedral lattice sites) leading to smooth and broad gain profiles (bandwidth: 130 nm) extending well above 2 µm and rendering Tm:CLTGG suitable for femtosecond pulse generation.
We report on the growth, structure, and polarized spectroscopy of a novel promising laser crystal, erbium-doped magnesium monotungstate, Er 3+ :MgWO 4 . 1.01 t.% Er 3+ :MgWO 4 was grown by the ...Top-Seeded Solution Growth method using Na 2 WO 4 as a solvent. The crystal structure was refined by the Rietveld method. Er 3+ :MgWO 4 belongs to the monoclinic class (sp. gr. P 2/ c , wolframite-type structure, lattice parameters: a = 4.6939(6) Å, b = 5.6747(4) Å, c = 4.9316(6) Å and β = 90.7858(4) Å. The transition intensities for Er 3+ ions were determined using the Judd-Ofelt theory accounting for an intermediate configuration interaction (ICI). Er 3+ ions in MgWO 4 exhibit intense, strongly polarized and broad absorption and emission bands owing to their accommodation in distorted low-symmetry sites (C 2 ). The stimulated-emission cross-section for the 4 I 13/2 → 4 I 15/2 transition is 0.31×10 −20 cm 2 at 1637 nm (light polarization: E || b ). The radiative lifetime of the 4 I 13/2 state is 4.85 ± 0.05 ms. The multiphonon non-radiative relaxation for Er 3+ excited multiplets is quantified. Er 3+ ions in MgWO 4 feature large Stark splitting of the ground-state, Δ E ( 4 I 15/2 ) = 435 cm -1 . Er 3+ :MgWO 4 is attractive for low-threshold lasers at ∼1.64 µm.
We report on the development of a novel laser crystal with broadband emission properties at ∼2 µm – a Tm 3+ ,Li + -codoped calcium tantalum gallium garnet (Tm:CLTGG). The crystal is grown by the ...Czochralski method. Its structure (cubic, sp. gr. I a 3 ¯ d , a = 12.5158(0) Å) is refined by the Rietveld method. Tm:CLTGG exhibits a relatively high thermal conductivity of 4.33 Wm -1 K -1 . Raman spectroscopy confirms a weak concentration of vacancies due to the charge compensation provided by Li + codoping. The transition probabilities of Tm 3+ ions are determined using the modified Judd-Ofelt theory yielding the intensity parameters Ω 2 = 5.185, Ω 4 = 0.650, Ω 6 = 1.068 10 −20 cm 2 and α = 0.171 10 −4 cm. The crystal-field splitting of the Tm 3+ multiplets is revealed at 10 K. The first diode-pumped Tm:CLTGG laser generates 1.08 W at ∼2 µm with a slope efficiency of 23.8%. The Tm 3+ ions in CLTGG exhibit significant inhomogeneous spectral broadening due to the structure disorder (a random distribution of Ta 5+ and Ga 3+ cations over octahedral and tetrahedral lattice sites) leading to smooth and broad gain profiles (bandwidth: 130 nm) extending well above 2 µm and rendering Tm:CLTGG suitable for femtosecond pulse generation.
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We have identified a novel PDE2 inhibitor series using fragment-based screening. Pyrazolopyrimidine fragment 1, while possessing weak potency (Ki = 22.4 μM), exhibited good binding ...efficiencies (LBE = 0.49, LLE = 4.48) to serve as a start for structure-based drug design. With the assistance of molecular modeling and X-ray crystallography, this fragment was developed into a series of potent PDE2 inhibitors with good physicochemical properties. Compound 16, a PDE2 selective inhibitor, was identified that exhibited favorable rat pharmacokinetic properties.
The primary objective of early drug discovery is to associate druggable target space with a desired phenotype. The inability to efficiently associate these often leads to failure early in the drug ...discovery process. In this proof-of-concept study, the most tractable starting points for drug discovery within the NF-κB pathway model system were identified by integrating affinity selection-mass spectrometry (AS-MS) with functional cellular assays. The AS-MS platform Automated Ligand Identification System (ALIS) was used to rapidly screen 15 NF-κB proteins in parallel against large-compound libraries. ALIS identified 382 target-selective compounds binding to 14 of the 15 proteins. Without any chemical optimization, 22 of the 382 target-selective compounds exhibited a cellular phenotype consistent with the respective target associated in ALIS. Further studies on structurally related compounds distinguished two chemical series that exhibited a preliminary structure-activity relationship and confirmed target-driven cellular activity to NF-κB1/p105 and TRAF5, respectively. These two series represent new drug discovery opportunities for chemical optimization. The results described herein demonstrate the power of combining ALIS with cell functional assays in a high-throughput, target-based approach to determine the most tractable drug discovery opportunities within a pathway.
Relevance of the paper is due to theoretical and practical necessity to study the peculiarities of design education. Modern designer shall, theoretically and methodologically, master the system of ...design engineering based on the laws affecting the form of product, methods of styling design and design quality analysis, basics of materials science and industrial design engineering. Design of industrial products shall draw upon historical, cultural, logistical, aesthetic and artistic foundations. The paper applies methods of cultural and historical analysis, comparative methods, methods of analysis and simulation of semiotic systems.
Authors, emphasizing training process integrity for design specialists, pay attention to the fact that in the modern urban world requirements to visual aesthetics are particularly important, ensuring videoecology of objects and environment, creating maximum emotional comfort. Ability to create emotional environment is due to form quality, generating peculiarities of psychological reactions as emotions. The study of form perception revealed the mechanism of creating emotional response associated with semantic capacity of design object and special features of its visual organization. Perception model of visual images in design was suggested, including recognition, comparison and dialogue processes. The findings are scientifically-based recommendations, tailored to visual perception and aimed at creating emotional comfort in design.
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