Photoluminescence of bulks and thin films of Eu3+-doped organic/inorganic hybrids

Organic-inorganic hybrids formed by polyether-based chains grafted to both ends to a siliceous backbone through urea cross-linkages (-NHC=O)NH-), named di-ureasil, have been used as host for incorporation of Eu3+ in the form of EuCl3. The bulks and the thin films, both optically transparent, were characterized by excitation, absorption and emission spectroscopy. Photoluminescence results point out that the Eu3+ ions occupy, at least, two distinct local environments. Besides, the processing method (thin films or bulks) has influence on the energy levels of the hybrid host probably due to the lower degree of organization of the thin films structure. (c) 2007 Elsevier B.V. All rights reserved.

Structural and Luminescence Properties of Silica-Based Hybrids Containing New Silylated-Diketonato Europium(III) Complex

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Abatacept in children with juvenile idiopathic arthritis: a randomised, double-blind, placebo-controlled withdrawal trial

Background Some children with juvenile idiopathic arthritis either do not respond, or are intolerant to, treatment with disease-modifying antirheumatic drugs, including anti-tumour necrosis factor (TNF) drugs. We aimed to assess the safety and efficacy of abatacept, a selective T-cell costimulation modulator, in children with juvenile idiopathic arthritis who had failed previous treatments.Methods We did a double-blind, randomised controlled withdrawal trial between February, 2004, and June, 2006. We enrolled 190 patients aged 6-17 years, from 45 centres, who had a history of active juvenile idiopathic arthritis; at least five active joints; and an inadequate response to, or intolerance to, at least one disease-modifying antirheumatic drug. All 190 patients were given 10 mg/kg of abatacept intravenously in the open-label period of 4 months. of the 170 patients who completed this lead-in course, 47 did not respond to the treatment according to predefined American College of Rheumatology (ACR) paediatric criteria and were excluded. of the patients who did respond to abatacept, arthritis, and 62 were randomly assigned to receive placebo at the same dose and timing. The primary endpoint was time to flare of arthritis. Flare was defined as worsening of 30% or more in at least three of six core variables, with at least 30% improvement in no more than one variable. We analysed all patients who were treated as per protocol. This trial is registered, number NCT00095173.Findings Flares of arthritis occurred in 33 of 62 (53%) patients who were given placebo and 12 of 60 (20%) abatacept patients during the double-blind treatment (p=0.0003). Median time to flare of arthritis was 6 months for patients given placebo (insufficient events to calculate IQR); insufficient events had occurred in the abatacept group for median time to flare to be assessed (p=0.0002). The risk of flare in patients who contined abatacept was less than a third of that for controls during that double-blind period (hazard ratio 0.31, 95% CI 0.16-0.95). During the double-blind period, the frequency of adverse events did not differ in the two treatment groups, Adverse events were recorded in 37 abatacept recipients (62%) and 34 (55%) placebo recipients (p=0.47); only two serious adverse events were reported, bouth in controls (p=0.50).Interpretation Selective modulation of T-cell costimulation with abatacept is a rational alternative treatment for children with juvenile idiopathic arthritis.Funding Bristol-Myers Squibb.

Lanthanide-Containing Light-Emitting Organic-Inorganic Hybrids: A Bet on the Future

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Studies on double selenates. I. Thermal decomposition of lanthanum and alkali metal double selenates

Thermogravimetry, differential thermal analysis and other methods of analysis have been used to study the decomposition of hydrated lanthanum and alkali metal double selenates up to 1300°C. The results showed slight variations in the initial temperature of the various intermediate decomposition stages of the double selenates, as compared with the initial temperature of the corresponding decomposition of the simple selenates. The results also permitted the suggestion of mechanisms of thermal decomposition of these compounds. © 1980.

Observations which indicate heterochromatinization of an extra chromosome in the salivary gland cells of Drosophila hybrids

Salivary gland cells of Drosophila mulleri/D. arizonensis aneuploid male hybrids carrying 3 microchromosomes exhibited morphological features which indicate heterochromatinization of one of the small polytene chromosomes. The process apparently changes the chromosome surface producing a coating with a net-like structure and a strong affinity for lacto-acetic orcein. The possibility of a dosage compensatory mechanism operating to counteract the effect of the extra chromosome is discussed on the basis of previous data which indicated that the microchromosomes of these species have ribosomal cistrons and are controlled by regulatory mechanisms especially evident in hybrids. © 1981 Dr W. Junk Publishers.

Lithium-lanthanum double chromates

Synthesis and crystallographic data are reported for low and high temperature forms of LiLa(CrO4)2. The compounds are closely related to lamellar rare earth phosphates and arsenates of sodium and to RbLu(CrO4)2. Lattice parameters of the orthorhombic (low temperature) and monoclinic (high temperature) forms are given. The low temperature form is moisture sensitive and Li+ ions are easily displaced by protons. Thermal decomposition takes place at 250 °C and results in the formation of LiCrO2, LaCrO4, LaCrO3 and Cr2O3. © 1993.

Lanthanum-lithium-sodium double chromates as ionic conductors

Lanthanum-lithium-sodium double chromates Li1-xNaxLa(CrO4)2 were prepared and analysed by means of admittance spectroscopy. Their a.c. conductivity parameters are correlated with structural details of high and low temperature forms of pure lanthanum-lithium double chromates. Lithium compounds show the lowest conductivity values and the highest activation energy for ion motion, while the sample Li0.5Na0.5La(CrO4)2 exhibits the highest conductivity 10-5 S cm-1 and the lowest activation energy 0.58 eV.

Differences in the number of sensilla coeloconica and sensilla ampullacea of segment 10 of the antennae of Africanized and Caucasian bees and of their F1 hybrids

The numbers of sensilla coeloconica and sensilla ampullacea of segment 10 of the antennae of Caucasian and Africanized worker bees and of their hybrids were counted with the aid of a scanning electron microscope. Africanized bees have fewer sensilla than Caucasian bees and the continuous distribution obtained from the F1 values suggests polygenic inheritance for the control of this trait. There are also indications that the hybrid Brazilian Apis mellifera studied here are close to typical African bees (Apis mellifera scutellata) in terms of number of sensilla.

Comment on Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions

We point out that if the Majoron-like scheme is implemented within a 3-3-1 model, there must exist at least three different mass scales for the scalar vacuum expectation values in the model. ©1999 The American Physical Society.

Double-blind comparison of venlafaxine and amitriptyline in outpatients with major depression with or without melancholia

The purpose of this study was to compare the efficacy and tolerability of venlafaxine and amitriptyline in outpatients with major depression with or without melancholia. This was an 8-week, multicentre, randomized, double-blind, parallel-group comparison of venlafaxine and amitriptyline. Outpatients with DSM-IV major depression, a minimum score of 20 on the 21-item Hamilton Depression Rating Scale (HAM-D), and depressive symptoms for at least 1 month were eligible. Patients were randomly assigned to venlafaxine or amitriptyline, both drugs titrated to a maximum of 150 mg/day until study day 15. The primary efficacy variables were the final on-therapy scores on the HAM-D, Montgomery-Asberg Depression Rating Scale and Clinical Global Impression severity scales. Data were evaluated on an intent-to-treat basis using the LOCF method. One hundred and 16 patients were randomized, and 115 were evaluated for efficacy. Both drugs showed efficacy in the treatment of depression with or without melancholia. No significant differences were noted between treatments for any efficacy parameter. However, significantly (p < 0.05) more patients in the amitriptyline group had at least one adverse event. These results should support the efficacy and tolerability of venlafaxine in comparison with amitriptyline for treating major depression with or without melancholia.

Full-color phosphors from amine-functionalized crosslinked hybrids lacking metal activator ions

Sol-gel derived hybrids that contain OCH2CH2 (polyethylene glycol, PEG) repeat units grafted onto a siliceous backbone by urea, -NHC(=O)NH-, or urethane, -NHC(=O)O-, bridges have been prepared. It is demonstrated that the white light PL of these materials results from an unusual convolution of a longer lived emission that originates in the NH groups of the urea/urethane bridges with shorter lived electron-hole recombinations occurring in the nanometer-sized siliceous domains. The PL efficiencies reported here (maximum quantum yields at room temperature of ≈ 0.20 ± 0.02 at a 400 nm excitation wavelength) are in the same range as those for tetramethoxysilane-formic acid, and APTES-acetic acid, sol-gel derived phosphors. The high quantum yields combined with the possibility of tuning the emission to colors across the chromaticity diagram present a wide range of potential applications for these hybrid materials.

Neutrinoless double beta decay with and without Majoron-like boson emission in a 3-3-1 model

We consider the contributions to the neutrinoless double beta decays in a SU(3)L⊗U(1)N electroweak model. We show that for a range of parameters in the model there are diagrams involving vector-vector-scalar and trilinear scalar couplings which can be potentially as contributing as the light massive Majorana neutrino exchange one. We use these contributions to obtain constraints upon some mass scales of the model, such as the masses of the new charged vector and scalar bosons. We also consider briefly the decay in which, in addition to the two electrons, a Majoron-like boson is emitted. ©2001 The American Physical Society.