Influence of temperature and excitation procedure on the athermal behavior of Nd(3+)-doped phosphate glass: Thermal lens, interferometric, and calorimetric measurements

In this work, thermal and optical properties of the commercial Q-98 neodymium-doped phosphate glass have been measured at low temperature, from 50 to 300 K. The time-resolved thermal lens spectrometry together with the optical interferometry and the thermal relaxation calorimetry methods were used to investigate the glass athermal characteristics described by the temperature coefficient of the optical path length change, ds/dT. The thermal diffusivity was also determined, and the temperature coefficients of electronic polarizability, linear thermal expansion, and refractive index were calculated and used to explain ds/dT behavior. ds/dT measured via thermal lens method was found to be zero at 225 K. The results provided a complete characterization of the thermo-optical properties of the Q-98 glass, which may be useful for those using this material for diode-pumped solid-state lasers. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3234396]

Thermal lens and interferometric method for glass transition and thermo physical properties measurements in Nd(2)O(3) doped sodium zincborate glass

In this work the time resolved thermal lens method is combined with interferometric technique, the thermal relaxation calorimetry, photoluminescence and lifetime measurements to determine the thermo physical properties of Nd(2)O(3) doped sodium zincborate glass as a function of temperature up to the glass transition region. Thermal diffusivity, thermal conductivity, fluorescence quantum efficiency, linear thermal expansion coefficient and thermal coefficient of electronic polarizability were determined. In conclusion, the results showed the ability of thermal lens and interferometric methods to perform measurements very close to the phase transition region. These techniques provide absolute values for the measured physical quantities and are advantageous when low scan rates are required. (c) 2008 Optical Society of America

2-(4-Methylphenyl)-1H-anthraceno-[1,2-d]imidazole-6,11-dione: a fluorescent chemosensor

In the title compound, C(22)H(14)N(2)O(2), the five rings of the molecule are not coplanar. There is a significant twist between the four fused rings, which have a slightly arched conformation, and the pendant aromatic ring, as seen in the dihedral angle of 13.16 (8)degrees between the anthraquinonic ring system and the pendant aromatic ring plane.

EIS study of Ti-23Ta alloy in artificial saliva

Although titanium and Ti-6Al-4V alloy have been widely used as dental materials, possible undesirable effects such as cytotoxic reactions and neurological disorder due to metal release led to the development of more corrosion resistant and V and Al free titanium alloys, containing Nb, Zr, Mo and Ta atoxic elements. Fluoride containing products used in the prevention of plaque formation and dental caries can affect the stability of the passive oxide films formed on the Ti alloys. In this work, the corrosion behaviour of the new Ti-23Ta alloy has been evaluated in artificial saliva of different pH and fluoride concentration using electrochemical impedance spectroscopy. Electrochemical impedance spectroscopy study showed that the oxide film formed on the alloy in artificial saliva consists of an inner compact film and an outer porous layer. The corrosion resistance of Ti-23Ta alloy which is reduced by increasing F concentration or decreasing pH is related to the resistance of the inner compact layer. The presence of fluoride and low pH of the saliva enhance the porosity of the oxide film and its dissolution.

Three-layer piezoelectrets from fluorinated ethylene-propylene (FEP) copolymer films

A process for preparing three-layer piezoelectrets from fluorinated ethylene-propylene (FEP) copolymer films is introduced. Samples are made from commercial FEP films by means of laser cutting, laser bonding, electrode evaporation, and high-field poling. The observed dielectric-resonance spectra demonstrate the piezoelectricity of the FEP sandwiches. Piezoelectric d (33) coefficients up to a few hundred pC/N are achieved. Charging at elevated temperatures can increase the thermal stability of the piezoelectrets. Isothermal experiments for approximately 15 min demonstrate that samples charged at 140A degrees C keep their piezoelectric activity up to at least 120A degrees C and retain 70% of their initial d (33) even at 130A degrees C. Acoustical measurements show a relatively flat frequency response in the range between 300 Hz and 20 kHz.

EXERGOECONOMIC COMPARISON OF ABSORPTION REFRIGERATION SYSTEMS INCLUDING A HIBRID ABSORPTION-EJECTO COMPRESSION CHILLER

The study of absorption refrigeration systems has had increasing importance in recent years due to the fact that the primary energy that is used in an absorption system can be heat available from a residual source or even a renewable one. Therefore, these systems not only use energy that would be rejected by the environment, but also they avoid the consumption of expensive fossil or electrical energies. The production cost of the mechanical work necessary to obtain a kW of refrigeration for mechanical compression cycle is normally higher than the cost for recovering the needed heat to obtain the same kW in an absorption cycle. Also, the use of these systems reduces impact on the environment by decreasing the emission of CO(2). We intend to show the performance of a hybrid absorption-ejecto compression chiller compared to conventional double- and single-effect water/lithium bromide systems, by means of an exergetic and exergoeconomic analysis of these configurations in order to calculate the exergy-based cost of a final product. The vapor compression refrigeration system is included in the results, as a comparisson to the performance of the absorption refrigeration systems analyzed.

Evaluation of culture media for enumeration of Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium animalis in the presence of Lactobacillus delbrueckii subsp bulgaricus and Streptococcus thermophilus

The study compared the growth capability of probiotic (Lactobacillus acidophilus La05, Lactobacillus casei Lc01 and Bifidobacterium animalis Bb12) and non-probiotic (Lactobacillus delbrueckii subsp bulgaricus and Streptococcus thermophilus) cultures on twenty-one culture media grouped according to selectivity: nonselective agars, selective agars without antibiotics and MRS agars containing different combinations of lithium chloride, cystein, bile salts and antibiotics. Four of these media were selected for quantitative enumeration of L acidophilus La05, L casei Lc01, and B. animalis Bb12. The best culture media and incubation conditions for enumeration of the probiotic cultures were: B. animalis: MRS agar with dicloxacillin, 37 degrees C or 42 degrees C, anaerobiosis; L acidophilus: MRS agar with bile salts, 37 degrees C or 42 degrees C, aerobiosis; L casei: MRS agar with lithium chloride and sodium propionate, 37 degrees C or 42 degrees C, aerobiosis or anaerobiosis. Plating on MRS with glucose replaced by maltose, 37 degrees C or 42 degrees C, anaerobiosis, will distinguish probiotic from non-probiotic cultures. For enumeration of each probiotic in a mixed culture, the following media and incubation conditions were recommended: B. animalis: 4ABC-MRS, 42 degrees C, anaerobiosis, L acidophilus: LC medium, 42 degrees C, aerobiosis or anaerobiosis and L casei: LP-MRS, 42 degrees C, aerobiosis or anaerobiosis. In all experiments, differences in counts using pour plating or surface plating were not significant (P <= 0.05). (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.

Evaluation of Some Biological Aspects of the Presence of Abrasive Silica and Thickening Silica in Basic Formulations of Dentifrices

The aim of this study was to evaluate some biological characteristics and toxicity of basic formulations of dentifrices containing such substances, and to compare them with two existing products in market which also contains silic in their formulations. In this way, it was evaluated some biological parameters: weight of the animals, oral toxicity, hematological parameters, urinary analysis, and histological evaluation. The thrombocytes were also statistically at normal levels. The glutamate-pyruvate transaminase (TGP) showed normal aspect in 5 of the tested groups, as in control. Meanwhile, the oxalacetic transaminase (AST) in one group had a small increase in the control group. Regarding urine, in exception the rats of one group, the rats of the 4 other experimental groups showed leukocytosis urinary statistically higher than the control group. The histological evaluation of the animals showed that specimens from liver, stomach, kidney and submandibular gland presented normal aspects for these organs, without significant characteristics related to inflammatory infiltrates in any of the 6 samples tested in their respective groups.

The effect of water fluoridation on the bone mineral density of young women [Saskatoon study]

Introduction: Osteogenic effects of therapeutic fluoride have been reported; however, the impact of exposure to low level water fluoridation on bone density is not clear. We investigated the effect of long-term exposure to fluoridated water from growth to young adulthood on bone mineral density (BMD). Methods: BMD was measured in 24 healthy women from Regina (fluoride 0.1 mg/L) and 33 from Saskatoon (fluoride 1.0 mg/L), with no differences between groups for height, weight, lifestyle or dietary factors. Results: Saskatoon women had significantly higher mean BMD at total anterior-posterior lumbar spine (APS) and estimated volumetric L3 (VLS), with no difference at total body (TB) or proximal femur (PF). Conclusion: Exposure to water fluoridation during the growing years may have a power impact on axial spine bone density in young women.

The treatment of tardive dyskinesia: A systematic review and meta-analysis

This systematic review aimed to collate randomized controlled trials (RCTs) of various interventions used to treat tardive dyskinesia (TD) and, where appropriate, to combine the data for mete-analysis, Clinical trials were identified by electronic searches, handsearches and contact with principal investigators. Data were extracted independently by two reviewers, for outcomes related to improvement, deterioration, side-effects and drop out rates. Data were pooled using the Mantel-Haenzel Odds Ratio (fixed effect model). For treatments that had significant effects, the number needed to treat (NNT) was calculated. From 296 controlled clinical trials, data were extracted from 47 trials. For most interventions, we could identify no RCT-derived evidence of efficacy. A meta-analysis showed that baclofen, deanol and diazepam were no more effective than a placebo. Single RCTs demonstrated a lack of evidence of any effect for bromocriptine, ceruletide, clonidine, estrogen, gamma linolenic acid, hydergine, lecithin, lithium, progabide, seligiline and tetrahydroisoxazolopyridinol. The meta-analysis found that five interventions were effective: L-dopa, oxypertine, sodium valproate, tiapride and vitamin E; neuroleptic reduction was marginally significant. Data from single RCTs revealed that insulin, alpha methyl dopa and reserpine were more effective than a placebo. There was a significantly increased risk of adverse events associated with baclofen, deanol, L-dopa, oxypertine and reserpine. Metaanalysis of the impact of placebo (n=485) showed that 37.3% of participants showed an improvement. Interpretation of this systematic review requires caution as the individual trials identified tended to have small sample sizes. For many compounds, data from only one trial were available, and where meta-analyses were possible, these were based on a small number of trials. Despite these concerns, the review facilitated the interpretation of the large and diverse range of treatments used for TD. Clinical recommendations for the treatment of TD are made, based on the availability of RCT-derived evidence, the strength of that evidence and the presence of adverse effects. (C) 1999 Elsevier Science B.V. All rights reserved.

p-cresol as a reversible acylium ion scavenger in solid-phase peptide synthesis

In this work we have defined the nature of the p-cresol and p-thiocresol adducts generated from acylium ions during HF cleavage, following contemporary Boc/benzyl solid-phase peptide synthesis. Contrary to the results in previous reports, we found that both p-cresol and p-thiocresol predominantly form. aryl esters under typical cleavage conditions. Initially we investigated a number of small peptides containing either a single glutamate residue or a C-terminal long-chain amino acid which allowed us to unambiguously characterize the scavenged side products. Whereas, the p-cresol esters are stable at 0 degrees C they rearrange irreversibly at higher temperatures (5-20 degrees C) to form aryl ketones. By contrast, p-thiocresol esters do not undergo a Fries rearrangement but readily undergo further additions of p-thiocresol to form ketenebisthioacetals and trithio ortho esters, even at low temperatures. Importantly, we found by LC/MS and FT-ICR MS analysis that peptides containing p-cresol esters at glutamyl side chains are susceptible to amidation and fragmentation reactions at these sites during standard mild base workup procedures. The significance of these side reactions was further demonstrated in the synthesis of neutrophil immobilization factor, a 26-residue peptide, containing four glutamic acid residues. The side reactions were largely avoided by mild hydrogen peroxide-catalyzed hydrolysis which converted the p-cresol adducts to the free carboxylic acids in near quantitative yield. The choice of p-cresol as a reversible acylium ion scavenger when coupled with the simple workup conditions described is broadly applicable to Boc/benzyl peptide synthesis and will significantly enhance the quality of peptides produced.

Presynaptic long-term depression at a central glutamatergic synapse: a role for CaMKII

CaMKII is a calcium-activated kinase that is abundant in neurons and has been strongly implicated in memory and learning. Here we show that low-frequency stimulation of glutamatergic afferents in hippocampal slices from juvenile domestic chicks results in long-term depression of synaptic transmission. This reduction does not require activation of NMDA or metabotropic glutamate receptors and does not require a rise in postsynaptic calcium. However, buffering presynaptic calcium prevents the reduction of the excitatory postsynaptic potential or current that is induced by low-frequency stimulation. in addition, application of the calmodulin antagonist calmidazolium, or the specific CaMKII antagonist KN-93, completely blocks long-term depression. These findings demonstrate a newsy discovered form of long-term synaptic depression in the avian hippocampus.

'Tetol': a stereo-rigid four-strand motif for alkali and alkaline earth metal ion coordination

The tetraalcohol 2,3,5,6-endo,endo,endo,endo-tetrakis(hydroxymethyl]bicyclo[2.2.1]heptane (tetol, 1) has been prepared and crystallises readily as the lithium(I) complex [Li(1)(2)]Cl, forming an oligomeric multi-chain structure in which pairs of alcohols from two crystallographically independent tetol molecules bind lithium ions tetrahedrally. However, formation of monomeric structures in solution is inferred from electrospray mass spectroscopy, which has also shown evidence of exchange of lithium ion in the complexed species by added alkaline earth ions. (C) 2000 Elsevier Science S.A. All rights reserved.

α′ phase stability in Nd-Li-sialon systems

The formability and stability of the alpha-sialon (alpha') phase was investigated in multi-cation Nd-Li-sialon systems. Four samples were prepared, ranging from a pure Nd-sialon to a pure Li-sialon, with two intermediate samples being prepared with either lithium or neodymium replacing the other alpha'-stabilising additive by 20 eq.%, as to maintain an equivalent design composition in all samples. After sintering, all samples were subsequently heat treated up to 192 h at 1450 and 1300 degreesC. While significant quantities of the beta'-sialon (beta' phase were found in most samples, the high-lithium Li-Nd-sialon sample was found to be almost pure a' phase after sintering. Furthermore, the long-term stability of the a' phase on heat treatment was also found to be superior in both multi-cation samples than in either of the single-alpha'-stabilising-cation samples. This is thought to be related to improved retention of the lithium in the multi-cation systems, as much of the lithium was found to volatilise during sintering in the neodymium-free sample. (C) 2002 Elsevier Science Ltd. All rights reserved.

Choking deaths: the role of antipsychotic medication

Background An increased risk of choking associated with antipsychotic medication has been repeatedly postulated. Aims To examine this association in a large number of cases of choking deaths. Method Cases of individuals who had died because of choking were linked with a case register recording contacts with public mental health services. The actual and expected rates of psychiatric disorder and the presence of psychotropic medication in post-mortem blood samples were compared. Results The 70 people who had choked to death were over 20 times more likely to have been treated previously for schizophrenia. They were also more likely to have had a prior organic psychiatric syndrome. The risk for those receiving thioridazine or lithium was. respectively, 92 times and 30 times greater than expected. Other antipsychotic and psychotropic drugs were not over-represented. Conclusions The increased risk of death in people with schizophrenia may be a combination of inherent predispositions and the use of specific antipsychotic drugs. The increased risk of choking in those with organic psychiatric syndromes is consistent with the consequences of compromised neurological competence. Declaration of interest None.