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Nine europium complexes with 2-pyrazinecarboxylic acid (Hpyca) and butanedioic acid (HBDA) were synthesized and characterized by elemental, IR, EDTA titration, ICP, and TG-DSC analyses. The results show that the complexes have the compositions of Eu(Pyca)(BDA)•2H2O, Eu0.7La0.3(Pyca)(BDA)•2H2O, Eu0.6La0.4(pyca)(BDA)•3H2O, Eu0.5La0.5(pyca)(BDA)•4H2O, Eu0.7Y0.3(Pyca)(BDA)•3H2O, Eu0.6Y0.4 (Pyca)(BDA)•2H2O, Eu0.5Y0.5(Pyca)(BDA)•3H2O, Eu0.7Gd0.3(Pyca)(BDA)•2H2O and Eu0.5Gd0.5(Pyca)(BDA)•2H2O. IR spectra indicate that lanthanide ions coordinate with the carboxylic oxygen atoms and nitrogen atoms of Hpyca and oxygen atoms of HBDA. Luminescence spectra show that the introduction of La3+, Y3+ or Gd3+ in the complexes does not change the luminescence peak position, but remarkably increases luminescent intensity of the europium complexes. The quantum yields of the complexes doped with inert lanthanide ions (La3+, Y3+ or Gd3+) are higher than that of the undoped europium complex. Furthermore, doping the inert lanthanide ions in right proportion can increase the luminescence lifetimes of complexes. Those complexes are of strong luminescence, low cost and practical value.

The purpose of this research was to correlate the state of agglomeration determined by the modeling of dissolution and de-agglomeration profiles, using mixtures of micronised indomethacin designed to have different dissolution rates and extents of particle agglomeration in dissolution media. Dissolution profiles were determined using the USP paddle method. De-agglomeration profiles were obtained from laser diffraction particle sizing of mixtures of indomethacin in dissolution media under non-sink conditions. Data were modeled and key parameters estimated using a non-linear least squares estimation algorithm. The key parameters of initial apparent volume concentrations as dispersed and agglomerated particles, and dissolution rate constants (for dissolution modeling), and the apparent volume concentrations of dispersible and non-dispersible agglomerates and the de-agglomeration rate constant (for de-agglomeration modeling) were related to indomethacin and sodium lauryl sulphate concentrations in the lactose-povidone mixtures. Micronised sodium lauryl sulphate added to the mixture was more effective in de-agglomeration than equivalent concentrations in the dissolution media. An excellent correlation existed between the total initial apparent volume concentration of agglomerates determined by dissolution and de-agglomeration (P=0.98). The use of key parameters estimated from the modeling of dissolution and de-agglomeration profiles provides a useful tool in dosage form development of formulations of poorly water soluble drugs.

The objective of this research was to model benzodiazepine deagglomeration profiles of percent agglomerated versus time when interactive mixtures containing micronized benzodiazepines were added to water. Micronized diazepam, nitrazepam, oxazepam, and, for ternary mixtures, micronized sodium lauryl sulfate were mixed with lactose-povidone granules (250-355 microm). After rapid dissolution of the lactose granules, bimodal particle size distributions of benzodiazepines, determined by laser diffraction particle sizing, represented dispersed and agglomerated distributions. The concentrations of agglomerated particle decreased with time and approached constant values. Deagglomeration profiles were determined and best modeled by a three-parameter single-exponential decay equation. A nonlinear least-squares approach was used to estimate the concentration of dispersible (C(0)) and nondispersible agglomerates (C(0a)) and the deagglomeration rate constant (K(a)). Increasing benzodiazepine and sodium lauryl sulphate concentrations in the lactose-povidone mixtures increased both dispersible and nondispersible agglomerate concentrations. Deagglomeration rate was relatively fast with half-lives around 15 min. The estimated parameters of C(0a) and K(a) may provide useful information in optimizing the design of formulations of poorly water soluble, micronized drugs to maximize their dispersion.

The objective of this research was to develop a method to characterize the degree of particle agglomeration using laser diffraction particle sizing, following the addition of benzodiazepine interactive mixtures to water. Interactive mixtures of diazepam, nitrazepam and oxazepam (up to 20% w/w) were prepared by mixing micronized benzodiazepines with lactose granules (250–355μm). Micronized sodium lauryl sulfate and cetrimide (up to 5% w/w) were added to the benzodiazepine-lactose interactive mixes to produce ternary mixtures. Particle size distributions of benzodiazepines, after addition of the interactive mixtures to water, were determined using laser diffraction particle sizing. Bimodal distributions representing dispersed particles and agglomerates were observed initially after lactose carrier dissolution. Partial agglomerate to dispersed particle transition occurred during a 60-min observation period for all mixtures, reaching a constant level of agglomeration after this time. Interactive mixtures with higher benzodiazepine concentrations displayed transition profiles with higher levels of agglomeration. The presence of surfactant in interactive mixtures dramatically decreased agglomeration. Sodium lauryl sulfate was more effective than cetrimide in dispersing agglomerates. The shape of the transition curves during de-agglomeration demonstrated the presence of stable agglomerates that remained after the initial transition; these may be important in explaining dissolution and absorption rates.

As an optical microscope with high resolution, two-photon excitation (TPE) fluorescence microscope is widely used in noninvasive 3D optical imaging of biological samples. Compared with confocal laser scanning microscope, TPE fluorescence microscope provides a deeper detecting depth. In spite of that, the image quality of sample always declines as the detecting depth increases when a noninvasive 3D optical imaging of thicker samples is performed. Mouse oocytes with a large diameter, which play an important role in clinical and biological fields, have obvious absorption and scattering effects. In the present paper, we performed compensation for two-photon fluorescence images of mouse oocyte chromosomes. Using volume as a parameter, the attenuation degree of these chromosomes was also studied. The result of our data suggested that there exists a severe axial intensity loss in two-photon microscopic images of mouse oocytes due to the absorption and scattering effects. It is necessary to make compensation for these images of mouse oocyte chromosomes obtained from two-photon microscopic system. It will be specially needed in studying the quantitative three-dimensional information of mouse oocytes.

Three compounds exist in the system Y2O3-Al2O3: Y4Al2O9, YAlO3, and Y3Al5O12 [1]. Y3Al5O12(YAG), and the most important of these compositions exists in the cubic form with a garnet structure. It is an important crystal for fluorescent and solid-state lasers, because it exhibits a thermally stable lattice, a well-determined crystal structure, and most importantly, resists saturation at high current excitation [2, 3]. Single crystals of Cr3+-doped YAG for example, are used in solid state lasers and Tb3+-doped YAG gives a characteristic narrow-band phosphor suitable for contrast-enhanced display applications [4, 5]. YAG phosphor powders are normally synthesized at relatively high temperatures by solid-state reaction between Y2O3 and Al2O3. Such conditions lead normally to powders of relatively large and varied grain sizes (5–20 μm) and varying impurity content. There are often problems in obtaining phase-pure material because of the intermediate formation of other phases, such as Y4Al2O9 and YAlO3 [6]. To achieve the desired phase purity and required particle size, high temperature treatment (>1600 ◦C) and extensive ball milling, which generally introduces additional impurities and defects and greatly reduces luminescence efficiency, are essential. For phosphor applications, it is desirable to have a fine particle size for high resolution and chemical purity for optimum chromaticity and brightness [7]. A few chemical synthesis techniques, such as sol-gel [8, 9], precipitation of hydroxides [10, 11], thermal decomposition of nitrates [12], hydrothermal treatment [13] and combus

In order to form a good generalization from a set of training instances, a clean training dataset is important. Unfortunately, real world data is never as perfect as we would like it to be and can often suffered from corruptions. In this paper, a new approach is proposed to identify and correct mislabeled training instances. For a given instance, we employ a Bayesian classifier to evaluate the probabilities of the instance belonging to all considered class labels. Then information entropy calculated from the probability distributions is used to evaluate the typicality of the instance belonging to considered class labels. Finally, the instance with low entropy, but with error prediction result, would be identified as mislabeled instance. Experimental results indicate that our approach gains comparative or better performance than previous techniques.

Fourteen solid coordination compounds of rare earth(Sm3+, Eu3+, Tb3+ and Dy3+ and Ln3+ (La3+, Gd3+ and Y3+)-doped Tb3+ with p-tert-butyl-calix[8] arene (LH8) have been synthesized and characterized. Elemental analysis, rare erth complexometry, 1H NMR spectra and TG-DTA have been studied. The results suggest that the complexes have the composition of [RE2 (LH2)(DMSO)5]DMSO, [RE2 (LH2) (DMF)5] 2DMF, [LnTb (LH2) (DMSO)5] DMSO and [LnTb (LH2) (DMF)5] 2DMF respectively. Fluorescence spectrum suggests that the Tb3+ complexes have characteristic luminescence, and its fluorescence intensity is enhanced after doping with La3+, Gd3+ and Y3+. The influence of the doping ions and two neutral ligands (DMSO and DMF) has also been discussed. In addition, the fluorescence lifetime of some complexes has been investigated.

Two complexes of crown ether europium (EuL) and crown ether lanthanum (LaL) were synthesized by europium perchlorate and lanthanum perchlorate with 18-crown-6(18-C-6) respectively. The heternuclear complexes of europium-lanthanum p-phthalic acid crown ether were prepared by the two complexes (EuL and LaL) with p-phthalic acid. The elemental analysis shows that its composition is EuLaL2L'(ClO4)4.6H2O(L = 18-C-6 and L' = p-C6H4 (COO)2). The IR spectra, UV-spectra and molar conductor indicate that both ligands (L and L') coordinate rare earth ions (Eu3+ and La3+), but perchlorate group is free. The fluorescence spectra show that the fluorescence intensities of the complex of heternuclear (EuLaL2L'(ClO4)4.6H2O) are more than eight times that of the crown ether europium complex. It was shown that the linked ligand (p-phthalic acid) can transfer the absorbed energy of Lanthanum-crown ether to europium-crown ether with high efficiency.

A series of dinuclear complexes of different molar ratio of Eu3+ to La3+ with benzoate and alpha,alpha'-dipyridyl have been synthesized in the anhydrous alcohol. Their composition was RE(Dipy)L3.H2O (RE = Eu3+ and La3+, L = C6H5COO-). Their UV spectra and IR spectra were studied. The UV absorption spectral peaks of benzoic acid and alpha,alpha'-dypyridyl shifted 2-9 nm in the complexes. The characteristic anti-symmetric and symmetric stretching vibrations of carboxylate group shifted to lower frequency, while the C=N stretching vibrations shifted to higher frequency in the complexes. These situations show that chemical bonds have formed between the ligands and the rare earth ions. The fluorescence spectra of the complexes were investigated, and the results indicate that the fluorescence emission intensity of europium ion was sensitized by lanthanum ion in the complexes. These facts show that not only the ligands but also the lanthanum complex can transfer the absorbed energy to Eu3+ ion in the complexes.