Supported molybdena catalysts: Characterization of oxidized,reduced, and sulfided MoO3 prepared by an adsorption method

Highly dispersed molybdena-titania catalyst can be prepared by an equilibrium adsorption method. In this method, molybdate anions adsorb onto the positively charged titania surfaces via electrostatic attraction by controlling the pH of the impregnating solution and they increase as an inverse function of the pH. ⁹⁵Mo-NMR and UV spectroscopic studies of impregnating solution show that the polymeric species like Mo₇O₂₄ ⁶-ions are adsorbed on titania in the acidic impregnating solution. XRD, Raman, and XPS data of the calcined samples show that mono-layer coverage of molybdenum oxide over-layer possesses a highly distorted MoO₆ group with a molecular geometry resembling the distorted square pyramid. The catalytic oxidation of methanol over the surface molybdate species on titania possesses higher turnover numbers and higher selectivities of partial oxidation products than the catalysts supported on alumina, silica, zirconia, or magnesia. Changes of the surface properties either after reduction and sulfiding treatment over monolayer catalyst on titania have also been investigated. The NO chemisorption and XPS studies show that two types of active sites appeared after reduction treatment: one site is active for hydrogenation of 1,3-butadiene and the other site is active for metathesis of propene. A higher degree coordinative unsaturations of MO is required for hydrogenation than metathesis. After sulfiding treatments of the catalyst, hydrogenation of 1,3-butadiene also requires triply coordinative unsaturation, and hydrogenolysis of thiophene requires the ensemble of doubly or triply coordinative unsaturations.     

p21Cip/WAF1 activation is an important factor for the ERK pathway dependent anti-proliferation of colorectal cancer cells

p21Cip/WAF1, an important regulator of cell proliferation, is induced by both p53- and extracellular signal regulated kinase (ERK) pathways. The induction of p21Cip/WAF1 occurs by prolonged activation of the ERKs caused by extracellular stimuli, such as zinc. However, not all the cells appeared to respond to ERK pathway dependent p21Cip/WAF1 induction. Here we investigated the cause of such difference using colorectal cancer cells. p21Cip/WAF1 induction and concomitant reduction of bromodeoxyuridine (BrdU) incorporation were observed by zinc treatment within HT-29 and DLD-1. However, HCT-116 cells with high endogenous p21Cip/WAF1 levels did not show any additional increment of p21Cip/WAF1 levels by zinc treatment and did maintain high BrdU incorporation level. The p21Cip/WAF1 induction by zinc depended upon prolonged activation of extracellular signal regulated kinase (ERK) was not observed in HCT-116 cells. The percentage of BrdU positive cells was 50% higher in p21Cip/WAF1 -/- HCT-116 cells compared to p21Cip/WAF1 +/+ HCT- 116 cells, and no cells induced p21Cip/WAF1 incorporated BrdU in its nucleus, yet confirming the importance of p21Cip/WAF1 induction in anti- proliferation. These results again support that p21Cip/WAF1 induction is a determinant in the regulation of colonic proliferation by the ERK pathway.     

A Partially Observable Markov Decision Process with Lagged Information

In actuality, we face lots of uncertainty in the application of a Markov process. In order to reduce such uncertainty, it is indispensable to use additional information concerning the state of the process.Among various kinds of additional information, this paper focuses on how to use uncertain delayed observation in a partially observable Markovian decision process (POMDP). This study develops a basic information structure, adding lagged observations to a general POMDP, and derives a rule for updating the state vector based on the information structure. This POMDP model is solved on the basis of a modified one-pass algorithm. An example is also given.     

An Extended Model for Establishing Dominance in Multiattribute Decisionmaking

This paper is concerned with the use of incomplete information about utilities and weights in multiattribute decisionmaking. Because of time pressure and/or lack of knowledge, a decision maker may only be able to provide incomplete information which might be expressed as a set of linear inequalities. If the decision maker's information on both weights and utilities is imprecisely identified, then the model for establishing pairwise dominance becomes a non-linear program. A method for obtaining non-dominated alternatives without solving the non-linear program is proposed using a simple weighted-additive function.     

Akt is involved in the inhibition of cell proliferation by EGF

Axin is a negative regulator of the Wnt/beta-catenin pathway and is involved in the regulation of axis formation and proliferation. Involvement of Axin in the regulation of other signaling pathways is poorly understood. In this study, we investigated the involvement of Akt in growth regulation by Axin in L929 fibroblasts stimulated by EGF. Akt activity was increased by EGF treatment and Ras activation, respectively. Both the EGF- and Ras-induced Akt activations were abolished by Axin induction, as revealed by both Western blot and immunocytochemical analyses. The proliferation and Akt activation induced by EGF were decreased by Axin induction, and the effects of EGF were abolished by treatment of an Akt-specific inhibitor. Therefore, Axin inhibits EGF-induced proliferation of L929 fibroblasts by blocking Akt activation.     

Crystal field effects on the photoluminescence properties of Y<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>La<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>VO<Subscript>4</Subscript>:Eu<Superscript>3+</Superscript> phosphors

Y_1−x La _x VO₄:Eu³⁺ phosphors were synthesized using a solid-state reaction. The microstructure and surface morphology of the Y_1−x La _x VO₄:Eu³⁺ phosphors were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. PL measurements of these phosphors revealed the characteristic Eu³⁺ emissions due to ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions. The Y_1−x La _x VO₄:Eu³⁺ phosphors showed strong red emission at 619 nm, which radiated from the hypersensitive transition ⁵D₀–⁷F₂ of Eu³⁺ ions. In particular, the incorporation of La into the YVO₄ lattice could induce a remarkable increase in PL. The highest emission intensity was observed in Y_0.2La_0.8VO₄:Eu³⁺, whose brightness was increased by more than 100 fold compared to that of the LaVO₄:Eu³⁺ phosphors. The Y_1−x La _x VO₄:Eu³⁺ phosphors with highly enhanced luminescence are expected to have applications in display devices.     

Role of α6β4 integrin in cell motility, invasion and metastasis of mammary tumors

Integrin α6β4 is the receptor for the laminin family of extracellular matrix proteins and is widely expressed in most epithelial tissues and Schwann cells. The expression of this integrin is up-regulated in most epithelial tumors, suggesting the role of α6β4 in their progression. The tumor microenvironment is also known to enhance the signaling competence of α6β4 through functional and physical interactions with other receptors. In this review, we discuss the biological mechanisms by which integrin α6β4 promotes carcinoma cell motility and invasion that leads to mammary tumor progression.     

Optical absorption and near infrared emission properties of Nd3+ ions in alkali lead tellurofluoroborate glasses

Nd³⁺ doped H₃BO₃–PbO–TeO₂–RF (R = Li, Na and K) glasses were prepared through melt quenching technique. Optical absorption and near infrared (NIR) fluorescence spectra were recorded at room temperature. The spectral intensities were analyzed in terms of the Judd–Ofelt (J–O) parameters (Ω_λ = 2, 4, 6). The covalency effect of Nd–O bond on the J–O parameters was estimated from the relative absorbance ratio (R) between ⁴I_9/2 → ⁴F_7/2 and ⁴I_9/2 → ⁴S_3/2 transitions. The effect of Nd–O covalency on the Ω₄ and Ω₆ intensity parameters as well as on the spontaneous emission probabilities (A_R) was discussed. Lomheim and Shazer hybrid method was applied to determine the fluorescence branching ratios (β_R) of each emission transition from the ⁴F_3/2 metastable level to its lower lying levels. The evaluated total radiative transition probabilities (A_T), stimulated emission cross-sections (σ_e) and gain bandwidth parameters (σ_e × Δλ_P) were compared with the earlier reports.     

Purification of squirt cellulose membrane from the cystic tunic of Styela clava and identification of its osteoconductive effect

The sea squirt has a tunic composed of cellulose fibers that are originated from animal cells and form a cellulose membrane that functions as a protective barrier and a skeleton of body. We purified the squirt cellulose membrane (SCM), about 100 μm thickness, from the cystic tunic of Styela clava. The SCM was turned out to be composed of pure native cellulose I in the analyses of X-ray diffraction, attenuated total reflectance Fourier transform-infrared spectroscopy. The inner surface of SCM showed numerous micropores in the meshworks of thin cellulose microfibrils, while the outer surface of SCM showed a few micropores. In order to know the osteoconductive effect of the SCM, it was applied to the perforated rat frontal bone, 8 mm diameter, for 4, 6, 8, 10, 12, and 16 weeks. The mesenchymal cells were tightly adhered to the inner surface of SCM and produced new bone there. The perforations to which the SCM was applied, were completely healed in 10 weeks, while the positive control group applied with the guided tissue regeneration (GTR) material, Bio-Gide^® showed incomplete healing until 16 weeks. Immunohistochemistry performed on the experimental group showed that BMP-2 and osteonectin were strongly positive in the early stage of bone healing at 4 weeks, while receptor activator of nuclear factor kappa B ligand (RANKL) became positive at 16 weeks. Particularly, the inner surface of SCM itself was consistently positive for the osteogenic proteins, indicating that the implanted SCM can absorb the osteogenic proteins from the stromal matrix of the host tissue. On the other hands, the positive control group implanted with Bio-Gide^® showed relatively weak reaction of the osteogenic proteins in the perforated bone area during the healing period, and the negative control group implanted none showed poor bony regeneration in the perforated wounds. Taken together, the SCM showed an excellent osteoconductive effect in the perforated rat frontal bone, which was quite comparable to the results of Bio-Gide^® implantation. Therefore, it is suggested that the SCM be a novel GTR material of a natural source with a strong osteoconductive effect on the injured bone.