Effects of dopamine reuptake inhibitors on food- and cocaine-maintained responding: II. Comparisons with other drugs and repeated administrations.

A previous study (J. R. Glowa, F. H. E. Wojnicki, D. Matecka, et al, 1995) showed that acute doses of GBR 12909 selectively decreased cocaine-maintained responding without affecting food-maintained responding. This report extended these observations to some related drugs and to the effects of repeated administration. When responding was maintained under a multiple fixed ratio (FR) 30 food, FR 30 cocaine schedule, acute doses of GBRR 12935, CFT, and d-amphetamine decrease cocaine-maintained responding more than food-maintained responding. However, in contrast to GBR 12909, none of these drugs completely decreased cocaine-maintained responding without affecting food-maintained-responding. Repeated administration of GBR 12909 sustained and of GBR 12935 improved, these selective deceases in cocaine-maintained responding. The selective effect of these dopamine reuptake inhibitors on cocaine-maintained responding is consistent with their known pharmacological selectivity for the dopamine reuptake side and can be well-maintained with repeated administration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hyper-crosslinked sorbents for hemoperfusion

Pore structure changes of swelling sorbents, which were obtained from styrene and divinylbenzene (DVB) by additional crosslinking with α,α′-dichloro-p-xylene in the presence of tin chloride catalyst and in dichloroethane solution, were examined. It was found that the amount of dichloroxylene influences the swelling decrease and the increase of sorption ability of sorbents for chemical compounds with low molecular weight. Hemocompatibility was imparted to the sorbent and it was useful for hemoperfusion when a small amount of sulfonyl groups (about 0.2 mmol/g) had been introduced.     

Reduced Graphene Oxides Modulate the Expression of Cell Receptors and Voltage-Dependent Ion Channel Genes of Glioblastoma Multiforme

The development of nanotechnology based on graphene and its derivatives has aroused great scientific interest because of their unusual properties. Graphene (GN) and its derivatives, such as reduced graphene oxide (rGO), exhibit antitumor effects on glioblastoma multiforme (GBM) cells in vitro. The antitumor activity of rGO with different contents of oxygen-containing functional groups and GN was compared. Using FTIR (fourier transform infrared) analysis, the content of individual functional groups (GN/exfoliation (ExF), rGO/thermal (Term), rGO/ammonium thiosulphate (ATS), and rGO/ thiourea dioxide (TUD)) was determined. Cell membrane damage, as well as changes in the cell membrane potential, was analyzed. Additionally, the gene expression of voltage-dependent ion channels (clcn3, clcn6, cacna1b, cacna1d, nalcn, kcne4, kcnj10, and kcnb1) and extracellular receptors was determined. A reduction in the potential of the U87 glioma cell membrane was observed after treatment with rGO/ATS and rGO/TUD flakes. Moreover, it was also demonstrated that major changes in the expression of voltage-dependent ion channel genes were observed in clcn3, nalcn, and kcne4 after treatment with rGO/ATS and rGO/TUD flakes. Furthermore, the GN/ExF, rGO/ATS, and rGO/TUD flakes significantly reduced the expression of extracellular receptors (uPar, CD105) in U87 glioblastoma cells. In conclusion, the cytotoxic mechanism of rGO flakes may depend on the presence and types of oxygen-containing functional groups, which are more abundant in rGO compared to GN.     

Directional movement of dendritic macromolecules on gradient surfaces

A gradient-driven methodology has been developed to manipulate the movement of dendritic macromolecules. Poly(propyleneimine) dendrimers, labeled with rhodamine B, are attached to glass substrates via multiple imine bonds. The dendrimers are able to move on the surface by the hydrolysis and re-formation of these imine bonds. In the absence of an external stimulus, this random movement results in a two-dimensional diffusion on the substrate. We are able to bias the movement of these nanoparticles by means of an aldehyde gradient on the glass substrate.     

Surface chemistry of n-octane modified silicon nanoparticles analyzed by IR, 13C CPMAS NMR, EELS, and TGA

The functionalization of silicon nanoparticles by thermally induced hydrosilylation in a one-pot process is reported. In contrast to the commonly applied thermally induced hydrosilylation, the process described here is carried out in the presence of hydrofluoric acid as a second phase and therefore proceeds at a lower conversion temperature. The surface functionalization of silicon nanoparticles was analyzed by IR, 13C CPMAS NMR, EELS, and TGA techniques. The applied procedure resulted in functionalized silicon nanoparticles with good chemical and thermal stability.     

Synthesis and Properties of Functionalized Alkylaldonamides

Application studies of novel saccharide-type nonionic surfactants were performed. The homolog series of N-alkyl-N-(2-hydroxyethyl)gluconamides and N-alkyl-N-(2-hydroxyethyl)glucoheptonamides (alkyl: n-C₁₀H₂₁, n-C₁₂H₂₅, and n-C₁₄H₂₉) were synthesized and their structures were confirmed by means of elemental analysis and ¹H-NMR spectroscopy. The investigations showed that the application of N-alkyl-N-(2-hydroxyethyl)aldonamides as surfactants in an aqueous media can be limited. This is because of their relatively high Krafft point temperature. However, some variants can be successfully applied in mixtures with an anionic surfactant: sodium salt of n-dodecyl sulfate (SDS). The addition of SDS causes significant improvement of the Krafft point temperatures. In some cases a synergistic effect was observed, i.e., the Krafft point temperature of the binary mixture was lower that the corresponding values for the solutions containing individual compounds. It is also remarkable, that the aqueous solutions of binary surfactant mixtures were characterized by improved foaming properties, as compared to that of pure SDS.

Interplay between size and crystal structure of molybdenum dioxide nanoparticles--synthesis, growth mechanism, and electrochemical performance

A detailed study is presented on the formation of MoO(2) nanoparticles from the dissolution of the precursor to the final rodlike product, with a focus on the exploration of the inorganic reaction occurring ahead of the nucleation step, and interplay between size and crystal structure of MoO(2). In situ X-ray absorption spectroscopy experiments show that the crystallization and the growth process of MoO(2) nanorods is initiated by rapid reduction of the MoO(2) Cl(2) precursor in benzyl alcohol and acetophenone. This reaction triggers the nucleation of 2 nm MoO(2) particles with spherical shape and hexagonal crystal structure. The transformation from spheres into rods emerges as a complex process driven by oriented attachment. High-resolution transmission electron microscopy and X-ray diffraction results provide evidence that the 2 nm particles first aggregate into 5-20 nm-large oriented assemblies. The increase in particle size induces the phase transition from hexagonal to the less symmetrical monoclinic crystal structure, and finally the transformation into rods. Is it shown that electrodes for lithium-ion batteries based on MoO(2) nanorods have a long-term cycling life. The specific discharge capacity even after 200 cycles at a discharge rate of 1 C is about 300 Ah kg(-1) .     

Thermal Properties of Surface-Modified \upalpha - and \upvarepsilon -Fe_{2}\hbox {O}_{3} Photocatalysts Determined by Beam Deflection Spectroscopy

In this work, a photothermal beam deflection spectroscopy setup is developed and applied for determination of the thermal parameters (thermal diffusivity and thermal conductivity) of \(\upalpha \) - and \(\upvarepsilon \) -Fe \(_{2}\hbox {O}_{3}\) nanodeposits on Si(100) substrates, specifically designed and tested as photocatalysts. It was observed that thermal parameters of the material strongly depend on the sample composition and morphology, which affect also the photocatalytic activity. The correlation between the thermal and photocatalytic properties are critically discussed based on the characteristics of the materials.     

Double Bond Stereochemistry Influences the Susceptibility of Short-Chain Isoprenoids and Polyprenols to Decomposition by Thermo-Oxidation

Isoprenoid alcohols are common constituents of living cells. They are usually assigned a role in the adaptation of the cell to environmental stimuli, and this process might give rise to their oxidation by reactive oxygen species. Moreover, cellular isoprenoids may also undergo various chemical modifications resulting from the physico‐chemical treatment of the tissues, e.g., heating during food processing. Susceptibility of isoprenoid alcohols to heat treatment has not been studied in detail so far. In this study, isoprenoid alcohols differing in the number of isoprene units and geometry of the double bonds, β‐citronellol, geraniol, nerol, farnesol, solanesol and Pren‐9, were subjected to thermo‐oxidation at 80 °C. Thermo‐oxidation resulted in the decomposition of the tested short‐chain isoprenoids as well as medium‐chain polyprenols with simultaneous formation of oxidized derivatives, such as hydroperoxides, monoepoxides, diepoxides and aldehydes, and possible formation of oligomeric derivatives. Oxidation products were monitored by GC‐FID, GC‐MS, ESI‐MS and spectrophotometric methods. Interestingly, nerol, a short‐chain isoprenoid with a double bond in the cis (Z) configuration, was more oxidatively stable than its trans (E) isomer, geraniol. However, the opposite effect was observed for medium‐chain polyprenols, since Pren‐9 (di‐trans‐poly‐cis‐prenol) was more susceptible to thermo‐oxidation than its all‐trans isomer, solanesol. Taken together, these results experimentally confirm that both short‐ and long‐chain polyisoprenoid alcohols are prone to thermo‐oxidation.     

Hot Corrosion of Ti–Re Alloys Fabricated by Selective Laser Melting

Selective laser melting (SLM) is an additive manufacturing process that enables novel alloy production by combining metals with significantly different physical properties. In this paper, the hot corrosion behavior of Ti–Re alloys fabricated by SLM was studied in a mixture of Na₂SO₄ and NaCl salts at 600 °C. The morphology and composition of the corrosion products were characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy and X-ray diffraction to understand the degradation mechanisms. It has been shown that the hot corrosion resistance of Ti–Re alloys was influenced by the chemical inhomogeneity of the oxide scale resulting from the presence of rhenium particles undissolved during the SLM process.