Neuronal expression of muskelin in the rodent central nervous system

Background  

The kelch repeat protein muskelin mediates cytoskeletal responses to the extracellular matrix protein thrombospondin 1, (TSP1), that is known to promote synaptogenesis in the central nervous system (CNS). Muskelin displays intracellular localization and affects cytoskeletal organization in adherent cells. Muskelin is expressed in adult brain and has been reported to bind the Cdk5 activator p39, which also facilitates the formation of functional synapses. Since little is known about muskelin in neuronal tissues, we here analysed the tissue distribution of muskelin in rodent brain and analysed its subcellular localization using cultured neurons from multiple life stages.     

Block copolymer containing poly(3‐hexylthiophene) and poly(4‐vinylpyridine): Synthesis and its interaction with CdSe quantum dots for hybrid organic applications

Poly(3‐hexylthiophene)‐b‐poly(4‐vinylpyridine) diblock copolymer was synthesized by RAFT polymerization of 4‐vinyl pyridine using a trithiocarbonate‐terminated poly(3‐hexylthiophene) macro‐RAFT agent. The optoelectronic properties and the morphology of the block copolymer blends with CdSe quantum dots were investigated. UV‐vis and fluorescence experiments were performed to prove the charge transfer between CdSe and poly(3‐hexylthiophene)‐b‐poly(4‐vinylpyridine) diblock copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and optical and transport properties of a phenyl‐substituted polythiophene

The synthesis and characterization of a novel polythiophene substituted with a 2′‐pentyloxy‐5′‐(1″′‐oxooctyl) phenyl group (PPOPT) is reported. The bulk transport properties of thin films of PPOPT are investigated by admittance spectroscopy. The dramatic effect of the phenyl side chain on the mobility of positive carriers in films of PPOPT is described. The photophysics of PPOPT in both solution and thin film is also investigated and correlated to substituent‐driven intrachain and interchain arrangements. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Improvement of pour point and oxidative stability of synthetic ester basestocks for biolubricant applications

For environmental reasons, as well as the dwindling source of petroleum, a new class of environmentally acceptable and renewable biolubricants based on plant oils is available. Even though plant oils possess excellent lubricant-related properties, there are some concerns about using it as biolubricant base oil. In this study we present a series of structures derived from oleic acid to be used as synthetic biolubricant basestocks. Measuring of pour point (PP), flash point, viscosity index (VI), oxidation onset temperature (OT) and signal maximum temperature (SMT) was carried out for each compound. Furthermore, the friction and wear properties were measured using a high-frequency reciprocating rig (HFRR). The resulting product structures were confirmed by NMR and FTIR spectroscopic analysis. The results showed that ethylhexyl 9-(octanoyloxy)-10-(behenoxy)octadecanoate with behenyl mid-chain ester exhibited the most favorable low temperature performance (PP ?48 °C) and ethylhexyl 9-(octanoyloxy)-10-(octyloxy)octadecanoate octyl mid-chain ester exhibited higher oxidation stability (OT 142 °C) than the other synthetic ester oils. On the other hand, the highest ball wear scan diameter was obtained for ethylhexyl 9-(octanoyloxy)-10-(behenoxy)octadecanoate while the lowest value was obtained for 9-hydroxy-10-octyloxyoctadecanoic acid. Overall, it was concluded that these synthetic ester oils have potential in formulation of industrial fluids for different temperature applications.     

Utility of 2-(5-methyl-1-phenyl-1H-pyrazol-4-yl)-2-oxo-N′-phenylaceto-hydrazonoyl bromide as precursor for synthesis of new functionalized heterocycles

2-(5-Methyl-1-phenyl-1H-pyrazol-4-yl)-2-oxo-N′-phenylaceto-hydrazonoyl bromide was synthesized and used as precursor for synthesis of some new 1,3,4-thiadiazoles, pyrrolo[3,4-c]pyrazoles, and 1,2,4-triazolo[4,3-a]pyrimidines. The mechanisms that account for formation of products were discussed. Also, the structures of all the newly synthesized products were confirmed based on elemental analysis, spectral data and by alternative methods.     

Synthesis and biological evaluation of <Superscript>99m</Superscript>Tc labeled aryl piperazine derivatives as cerebral radiotracers

The aim of this study is to develop cerebral radiotracers for central nervous system receptors imaging. The synthesis, characterization and biological evaluation of two aryl piperazine ^99mTc-radiocomplexes based on the piano stool motif [CpM(CO₃)] (Cp = cyclopentadienyl, M = ^99mTc/Re) is reported. The ^99mTc-radiocomplexes were obtained quickly (time < 5 min) with high radiochemical yields. The ^99mTc-radiocomplexes characterized by high performance liquid chromatography comparison with the rhenium surrogates have both a suitable lipophilicity and are able to cross the blood brain barrier with 0.43 ± 0.05 and 1.96 ± 0.06% ID/g of brain uptake, at 10 min post injection.     

Deuteration of Water Enables Self‐Organization of Phospholipid‐Based Reverse Micelles

Phospholipid‐based reverse micelles are composed of branched cylinders. Their branching points are known to attract themselves and to slide along branches. The rate of this sliding is governed by the lifetime of H(D)‐bonded water bridges between phospholipid molecules. This lifetime is increased when the water is deuterated. On condition that the water contains at least 40 D atoms %, water/dipalmitoylphosphatidylcholine (DPPC)/deuterated pyridine reverse micelles with the composition 1.1:1:250 (v/v) have been shown to self‐organize into a liquid crystal in the 310–316 K temperature range. The mechanism of this self‐organization is unraveled by following the FTIR and ¹H NMR spectra of more concentrated micelles upon heating. During the preparation of micelles, pyridine‐(D⁺)H⁺ ions are formed. They give rise to hydron transfers, under the influence of the DPPC electric charges, evidenced by two broad FTIR absorptions above (BB1) and below (BB2) the ν(C? O) stretch. These hydron transfers occur along strong (D⁺)H⁺ bonds of pyridinium ions with pyridine (BB1) and DPPC C?O groups (BB2). The proton transfers at the interface of micelles, relayed in the continuous pyridine medium, create a tenuous link between separated micelles, thus facilitating their organization. Upon heating, DPPC heads shrink and DPPC chains expand to make wedge‐shaped DPPC molecules. The micelles then change in shape: cylinders constrict and enclosed water drifts towards branching points, which swell. Branching points of neighboring micelles come into contact. Due to the deuteration of water these contacts are prolonged and H bonds are formed between DPPC molecules located in each branching point. Upon storage at 39 °C, these branching points fuse. The lateral diffusion of DPPC molecules becomes free, as evidenced by a narrowing of all ¹H NMR resonances. Upon further heating, reorganization into a liquid crystal occurs.     

Étude structurale de britholite au césium Sr7La2Cs(PO4)5(SiO4)F2

Several studies demonstrated the ability of britholites to retain radionuclides such as the caesium and actinides. Therefore, three compounds with formulas Sr₈LaCs(PO₄)₆F₂, Sr₇La₂Cs(PO₄)₅(SiO₄)F₂ and Sr₂La₇Cs(SiO₄)₆F₂, were prepared by solid state reaction. However, it seems that only the mono-silicated composition was obtained in a pure state. In this present work, the X-ray diffraction and magnetic nuclear resonance have been used to investigate the structure for this composition. The results showed that in fact this phase was not pure, but it was mixed with a secondary phase, SrLaCs(PO₄)₂. The refinement by the Rietveld method allowed also to precise the distribution of La³⁺ and Cs⁺ ions between the two cationic sites of the apatite.