Simultaneous acquisition of magnetic resonance spectroscopy (MRS) data and positron emission tomography (PET) images with a prototype MR-compatible, small animal PET imager

Multi-modality imaging (such as PET-CT) is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET, fused with anatomical images created by MRI, allow the correlation of form with function. Perhaps more exciting than the combination of anatomical MRI with PET, is the melding of PET with MR spectroscopy (MRS). Thus, two aspects of physiology could be combined in novel ways to produce new insights into the physiology of normal and pathological processes. Our team is developing a system to acquire MRI images and MRS spectra, and PET images contemporaneously. The prototype MR-compatible PET system consists of two opposed detector heads (appropriate in size for small animal imaging), operating in coincidence mode with an active field-of-view of approximately 14 cm in diameter. Each detector consists of an array of LSO detector elements coupled through a 2-m long fiber optic light guide to a single position-sensitive photomultiplier tube. The use of light guides allows these magnetic field-sensitive elements of the PET imager to be positioned outside the strong magnetic field of our 3T MRI scanner. The PET scanner imager was integrated with a 12-cm diameter, 12-leg custom, birdcage coil. Simultaneous MRS spectra and PET images were successfully acquired from a multi-modality phantom consisting of a sphere filled with 17 brain relevant substances and a positron-emitting radionuclide. There were no significant changes in MRI or PET scanner performance when both were present in the MRI magnet bore. This successful initial test demonstrates the potential for using such a multi-modality to obtain complementary MRS and PET data.     

Study of thermal behaviour of some edible mushrooms

This paper is aimed to analyse the thermal behaviour in air of edible mushrooms through nonisothermal (TG, DTG, DTA) and calorimetric (Berthelot calorimeter) methods. The studied mushrooms were Pleurotus ostreatus spontaneously grown and from culture and Agaricus bisporus from culture, currently used in alimentation but insufficiently investigated from this point of view. The analysis of TG–DTG–DTA curves has indicated that the degradation mechanism is complex and characteristic to every species and major differences between the cap and the stipe of investigated mushrooms have not been recorded. These species are thermally stable in the range of 30–160 °C. The thermal stability in terms of initial degradation temperature (T _i °C) and the temperature corresponding to the conversion grade (T _α=0.03 °C) indicate that the stipe has a thermal stability close to the cap one and that the cultivated mushrooms are more thermally stable than those spontaneously grown. The obtained results concerning the combustion of the sample using Berthelot calorimeter are in accordance with the TG–DTG–DTA analysis. The residue obtained is a measure of the mineral content and is quantitatively close.     

Thermal behaviour of some novel antimicrobials based on complexes with a Schiff base bearing 1,2,4-triazole pharmacophore

A series of complexes of type [ML(CH₃COO)(OH₂)₂] (M: Co, Ni; HL: 2-[(E)-1H-1,2,4-triazol-3-ylimino)methyl]phenol)) and [M₂L₂(CH₃COO)₂(OH₂)_n] (M: Cu, n = 2; M: Zn, n = 0) were synthesised by template condensation. The compounds were characterised with microanalytical, ESI–MS, IR, electronic, EPR spectra and magnetic data at room temperature. Based on the IR and ESI–MS spectra, a dinuclear structure with the acetate as bridge was proposed for Cu(II) and Zn(II) complexes. The dinuclear structure of Cu(II) complex is also consistent with both magnetic behaviour and EPR spectrum. The thermal analyses have evidenced processes as water elimination, acetate decomposition, as well as oxidative degradation of the Schiff base. The final decomposition product was the most stable metal oxide as indicated by powder X-ray diffraction. The cobalt and copper compounds exhibited a broad spectrum of antibacterial activity towards both planktonic and biofilm-embedded cells. The complexes exhibit a low cytotoxicity except for Cu(II) species that induces the early apoptosis for the HEp 2 cells.     

Synthesis and thermal behavior of new ambazone complexes with some transitional cations

Ambazone is a pharmaceutical compound that possesses antiseptic activity and tested as well for anti-tumor properties. Metal complexes of Zn(II), Fe(III), and Cu(II) containing ambazone as ligand were synthesized using a molar ratio salt:ligand of 1:1, heating the mixture up to 50 °C for 6 h. Coordination compounds were characterized by thin-layer chromatography, FT-IR spectroscopy, elemental analysis, and thermal behavior. The non-isothermal experiments were carried out in order to investigate the thermal degradation process of these complexes and were performed in a dynamic air atmosphere at a heating rate β = 10 °C min^?1 from ambient temperature, up to 500 °C. It was revealed that decomposition process is a multistadial one.     

Naphthocrown‐Strapped Calix[4]pyrroles: Formation of Self‐Assembled Structures by Ion‐Pair Recognition

A new approach to the construction of self‐assembled structures is reported that is based on ion‐pair recognition. Towards this end, the calix[4]pyrrole naphthocrown‐4 hybrid structures 2 and 3 were prepared. These multitopic receptors contain recognition sites for both anions and cations. On the basis of solution‐phase ¹H NMR spectroscopic analysis and solid‐state single‐crystal X‐ray diffraction structural studies, it was established that receptors 2 and 3 are able to bind specific ion pairs with high selectivity via different binding modes. In the case of CsF and CsCl, the ion‐pair complexes formed from receptors 2 and 3 were found to self‐assemble to produce either linear supramolecular polymeric crystalline solids or nanotube‐like cyclic hexamers depending on the specific choice of ion pairs and crystallization solvents. Proton NMR studies provided evidence for solution‐phase self‐association in organic media.     

Efficient Biocatalytic Degradation of Pollutants by Enzyme‐Releasing Self‐Propelled Motors

The first example of a self‐propelled tubular motor that releases an enzyme for the efficient biocatalytic degradation of chemical pollutants is demonstrated. How the motors are self‐propelled by the Marangoni effect, involving simultaneous release of SDS surfactant and the enzyme remediation agent (laccase) in the polluted sample, is illustrated. The movement induces fluid convection and leads to the rapid dispersion of laccase into the contaminated solution and to a dramatically accelerated biocatalytic decontamination process. The greatly improved degradation efficiency, compared to quiescent solutions containing excess levels of the free enzyme, is illustrated for the efficient biocatalytic degradation of phenolic and azo‐type pollutants. The high efficiency of the motor‐based decontamination approach makes it extremely attractive for a wide‐range of remediation processes in the environmental, defense and public health fields.     

Synthesis and characterization of palladium(II) complexes [PdX2(p-diben)] (X = Cl,Br, I,N3, or NCO; p-diben = N,N′-bis(4-dimethylaminobenzylidene)ethane-1,2-diamine): crystal structure of [Pd(N3)2(p-diben)]

Five new complexes of general formula [PdX₂(p-diben)], where p-diben = N,N′-bis(4-dimethylaminobenzylidene)ethane-1,2-diamine) (1) and X = Cl (2), Br (3), I (4), N₃ (5), or CNO (6), were synthesized and characterized by physicochemical and spectroscopic methods. The crystal structure of compound (5) was determined by single-crystal X-ray diffraction. Complexes 2–6 were characterized as N,N-chelated products. The crystal structure confirmed this formulation for [Pd(N₃)₂(p-diben)], besides showing the isomerism inversion of one of the C=N bonds, caused by Pd(II) coordination.     

Magnetic mixed matrix membranes in air separation

Ethylcellulose (EC) or linear polyimide (LPI) and magnetic neodymium powder particles MQP-14-12 were used for the preparation of inorganic-organic hybrid membranes. For all the membranes, N₂, O₂ and air permeability were examined. Mass transport coefficients were determined using the Time Lag System based on dynamic experiments in a constant pressure system. The results showed that the membrane permeation properties were improved by the addition of magnetic neodymium particles to the polymer matrix. The magnetic ethylcellulose and polyimide membranes exhibited higher gas permeability and diffusivity, while their permeability selectivity and solubility were either unchanged or slightly increased. Polyimide mixed matrix membranes were characterised by a higher thermal and mechanical stability, larger filler loading, better magnetic properties and reasonable selectivity in the air separation.     

A spectrophotometric method for plant pigments determination and herbs classification

Twenty herbs, showing medicinal benefits on human life, like Taraxacum officinale, Plantago lanceolata, Hypericum perforatum, Ocimum basilicum, Melissa officinalis, Mentha piperita, and others, were tested. The percentage content of pigments, i.e. chlorophylls, carotenoids, and flavonoids, in the chosen herbs was determined. The spectrophotometric method, which is quick and readily available, was used. Measurements required pigment extraction with a solvent. Ethanol was used for the determination of chlorophylls and carotenoids, and acetone for the determination of flavonoids. Hierarchical agglomerative cluster analysis was performed in order to confirm the experimental results. The study of flavonoids content showed an interesting regularity which can be used for the classification of herbs. Plants belonging to the Lamiaceae family showed the flavonoids content in the range from 0.18 % to 0.68 %, whereas those belonging to the Apiaceaehas family showed the flavonoids content in the 0.75–1.20 % range.