PVC membrane selective electrode for determination of cadmium(II) ion in chocolate samples

Benzil bis（carbohydrazone） （BBC） is prepared and explored as new NN Schiff’s base, which plays the role of an excellent ion carrier in the construction of a Cd（II） ion membrane sensor. The tris（2-ethylhexyl） phosphate best performance corresponds to a membrane composition of 30%poly （vinyl chloride）, 65%（TEHP）, 3.5%BBC and 1.5%tetradodecyl-ammoniumtetrakis（4-chlorophenyl） borate （ETH 500）. This sensor shows very good selectivity and sensitivity towards cadmium ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition, selectivity, pH and influence of additive on the response properties of electrode were investigated. The response mechanism was discussed in the view of UV-spectroscopy. The electrode exhibits a Nernstian behavior （with slope of 29.7 mV per decade） over a very wide concentration range from 1.0×10^-1 to 1.0×10^-8 mol·L^-1 with a detection limit of 3.2×10^-8 mol·L^-1. It shows rela-tively fast response time in whole concentration range （〈8 s） and can be used for at least 10 weeks in the pH range of 2.0-9.0. The proposed sensor is successfully used for the determination of cadmium in different chocolate sam-ples and as indicator electrode in titration with ethylene diamine tetraacetate （EDTA）.     

Synthesis and characterization of Schiff base ligand as a carrier and its application for construction of new Mn(II) sensors and their use in petroleum water samples

The ligand (PBABMDP: 2,2′-((1E,1′E)-(1,3-phenylene bis(azanylylidene)) bis(methanyly-lidene))-diphenol was synthesized in a reasonable yield from 2-hydroxybenzaldehyde and m-phenylenediamine and studied using IR, mass, and ¹H NMR spectroscopy. PBABMDP has been used as a neutral carrier to make a new carbon paste (CPS) and screen-printed sensors (SPS) that are highly selective to Mn(II) ions. They revealed linear concentration ranges from 1.0 × 10^-7 to 1.0 × 10^-1 mol L^-1 for CPS (sensor I) and from 3.7 × 10^-8 to 1.0 × 10^-1 mol L^-1 for SPS (sensor II), respectively, with Nernstian slopes of 29.01 ± 0.97 and 29.96 ± 0.57 mV decade^-1. For sensor I and sensor II, the detection limit, and the response time of the sensors were: 1.0 × 10^-7 and 3.7 × 10^-8 mol L^-1 and 9 and 6 s, respectively. Without observe a divergence, the paste may be used for more than 95 or 182 days and the sensors can be used between 4.0 and 7.5 pH and 3.0 to 8.5 pH. For sensor I and II, the isotherm coefficient of the sensors was 0.000105 and 0.000168 V/^oC. The proposed sensors were applied to the determination of Mn(II) ions in real petroleum water samples. The results achieved using this potentiometric method and those obtained with AAS were well agreed.     

Melatonin Stimulates Dendrite Formation and Complexity in the Hilar Zone of the Rat Hippocampus: Participation of the Ca++/Calmodulin Complex

Melatonin (MEL), the main product synthesized by the pineal gland, stimulates early and late stages of neurodevelopment in the adult brain. MEL increases dendrite length, thickness and complexity in the hilar and mossy neurons of hippocampus. Dendrite formation involves activation of Ca²⁺/Calmodulin (CaM)-dependent kinase II (CaMKII) by CaM. Previous work showed that MEL increased the synthesis and translocation of CaM, suggesting that MEL activates CaM-dependent enzymes by this pathway. In this work we investigated whether MEL stimulates dendrite formation by CaMKII activation in organotypic cultures from adult rat hippocampus. We found that the CaMKII inhibitor, KN-62, abolished the MEL stimulatory effects on dendritogenesis and that MEL increased the relative amount of CaM in the soluble fraction of hippocampal slices. Also, PKC inhibition abolished dendritogenesis, while luzindole, an antagonist of MEL receptors (MT1/2), partially blocked the effects of MEL. Moreover, autophosphorylation of CaMKII and PKC was increased in presence of MEL, as well as phosphorylation of ERK1/2. Our results indicate that MEL stimulates dendrite formation through CaMKII and the translocation of CaM to the soluble fraction. Dendritogenesis elicited by MEL also required PKC activation, and signaling through MT1/2 receptors was partially involved. Data strongly suggest that MEL could repair the loss of hippocampal dendrites that occur in neuropsychiatric disorders by increasing CaM levels and activation of CaMKII.     

Contact lens wear by Royal Air Force aircrew in World War II

PurposeTo provide an overview of the use of contact lenses by RAF aircrew in World War II by identifying some of the fitters and wearers and appraising the clinical results that they achieved.MethodsA wide-ranging literature search was undertaken that encompassed peer-reviewed journals, non-refereed publications, books, official publications, newspapers and archived documents.ResultsThirty-one aircrew are known to have worn sealed scleral lenses in order to meet the required visual standards. Of these, only two were considered to be completely unsuccessful, one of whom was unilaterally aphakic. One additional case of undisclosed contact lens wear was found and the identity of this officer was established. Brief biographies of a few pilots establish the context of their contact lens wear.ConclusionOverall, the results of scleral lens wear were variable reflecting those achieved by civilian patients of the period. While three men complained of discomfort due to heat and glare, one pilot experienced no photophobia when flying above white clouds in brilliant sunshine and another found no difficulty caused by altitude or tropical climate. Wearing time ranged from about 2 h to 16, or more, hours. In about a third of the cases, wearing time was limited due to the onset of a form of contact lens induced-epithelial oedema known as Sattler's veil and effective solutions to this problem were not implemented until after the war.     

Numerical analysis of the ENF and ELS tests applied to mode II fracture characterization of cortical bone tissue

The objective of this work is to verify numerically the adequacy of the ENF and the ELS tests to determine the fracture toughness under mode II loading of cortical bovine bone tissue. A data‐reduction scheme based on the specimen compliance and the equivalent crack concept is proposed to overcome the difficulties inherent to crack monitoring during its growth. A cohesive damage model was used to simulate damage initiation and growth, thus assessing the efficacy of the proposed data‐reduction scheme. The influences of the initial crack length, local strength and toughness on the measured fracture energy were analysed, taking into account the specimen length restriction. Some limitations related to spurious influence on the fracture process zone of the central loading in the ENF test, and clamping conditions in the ELS test were identified. However, it was verified that a judicious selection of the geometry allows, in both cases, a rigorous estimation of bone toughness in mode II.     

A novel wavelet seismic denoising method using type II fuzzy

Wavelet based denoising of the observed non stationary time series earthquake loading has become an important process in seismic analysis. The process of denoising ensures a noise free seismic data, which is essential to extract features accurately (max acceleration, max velocity, max displacement, etc.). However, the efficiency of wavelet denoising is decided by the identification of a crucial factor called threshold. But, identification of optimal threshold is not a straight forward process as the signal involved is non-stationary. i.e. The information which separates the wavelet coefficients that correspond to the region of interest from the noisy wavelet coefficients is vague and fuzzy. Existing works discount this fact. In this article, we have presented an effective denoising procedure that uses fuzzy tool. The proposal uses type II fuzzy concept in setting the threshold. The need for type II fuzzy instead of fuzzy is discussed in this article. The proposed algorithm is compared with four current popular wavelet based procedures adopted in seismic denoising (normal shrink, Shannon entropy shrink, Tsallis entropy shrink and visu shrink).It was first applied on the synthetic accelerogram signal (gaussian waves with noise) to determine the efficiency in denoising. For a gaussian noise of sigma = 0.075, the proposed type II fuzzy based denoising algorithm generated 0.0537 root mean square error (RMSE) and 16.465 signal to noise ratio (SNR), visu shrink and normal shrink could be able to give 0.0682 RMSE with 14.38 SNR and 0.068 RMSE with 14.2 SNR, respectively. Also, Shannon and Tsallis generated 0.0602 RMSE with 15.47 SNR and 0.0610 RMSE with 15.35 SNR, respectively. The proposed method is then applied to real recorded time series accelerograms. It is found that the proposal has shown remarkable improvement in smoothening the highly noisy accelerograms. This aided in detecting the occurrence of ‘P’ and ‘S’ waves with lot more accuracy. Interestingly, we have opened a new research field by hybriding fuzzy with wavelet in seismic denoising.     

The effects of Ca(II) and Mg(II) ions on the flotation of spodumene using NaOL

The effects of Ca(II) and Mg(II) ions on the flotation of spodumene using sodium oleate (NaOL) as the collector were investigated by micro-flotation tests, zeta-potential measurements, absorption measurements, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analyses. The micro-flotation results indicated that the pH value has a significant influence on the activation of spodumene minerals by Ca(II) and Mg(II) ions. Good floatability of spodumene was obtained with Ca(II) and Mg(II) ions at a pH of 12.5 and 10.0, respectively. In strongly alkaline solutions, Ca(II) and Mg(II) ions readily form hydroxy complexes (CaOH(I) and MgOH(I)) and precipitates (Ca(OH)₂ and Mg(OH)₂). FT-IR and XPS analyses revealed that the hydroxy complexes and the precipitates adsorbed onto the spodumene surface. These species contributed to the formation of oleate complexes and thus increased the amount of collector adsorption and the floatability of spodumene.