Behavioral effects of centrally administered arginine vasopressin in the rat fetus.

Arginine–8 vasopressin (AVP) was administered to rat fetuses on Embryonic Day 20 via intracisternal (IC), intrahemispheric (IH), or intrathecal (IT) injection. The IC administration of AVP promoted a 4-fold increase in motor activity, including the uncommon patterns of mouthing, licking, and facial wiping. The IH injection of AVP had little effect on fetal behavior, but IT injection resulted in pronounced increases in fetal activity, including mouthing, licking, and wiping. The IT administration of a V? antagonist blocked AVP effects, whereas IH injection potentiated AVP-induced changes in fetal behavior. The IC blockade of V? receptors suppressed facial wiping to a chemosensory fluid (lemon) and reduced oral grasping of an artificial nipple, whereas IH injection of the V? antagonist promoted facial wiping responses and increased grasping of the nipple. These data suggest that AVP may play a role in the development of responsiveness to stimuli encountered in the context of suckling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for Glass–glass Interfaces in a Columnar Cu–Zr Nanoglass

Comprehensive analyses of the atomic structure using advanced analytical transmission electron microscopy-based methods combined with atom probe tomography confirm the presence of distinct glass–glass interfaces in a columnar Cu-Zr nanoglass synthesized by magnetron sputtering. These analyses provide first-time in-depth characterization of sputtered film nanoglasses and indicate that glass–glass interfaces indeed present an amorphous phase with reduced mass density as compared to the neighboring amorphous regions. Moreover, dedicated analyses of the diffusion kinetics by time-of-flight secondary ion mass spectroscopy (ToF SIMS) prove significantly enhanced diffusivity, suggesting fast transport along the low density glass–glass interfaces. The present results further indicate that sputter deposition is a feasible technique for reliable production of nanoglasses and that some of the concepts proposed for this new class of glassy materials are applicable.     

Catalytic Sulfation of Betulin with Sulfamic Acid: Experiment and DFT Calculation

Betulin is an important triterpenoid substance isolated from birch bark, which, together with its sulfates, exhibits important bioactive properties. We report on a newly developed method of betulin sulfation with sulfamic acid in pyridine in the presence of an Amberlyst^®15 solid acid catalyst. It has been shown that this catalyst remains stable when being repeatedly (up to four cycles) used and ensures obtaining of sulfated betulin with a sulfur content of ~10%. The introduction of the sulfate group into the betulin molecule has been proven by Fourier-transform infrared, ultraviolet-visible, and nuclear magnetic resonance spectroscopy. The Fourier-transform infrared (FTIR) spectra contain absorption bands at 1249 and 835–841 cm⁻¹; in the UV spectra, the peak intensity decreases; and, in the nuclear magnetic resonance (NMR) spectra, of betulin disulfate, carbons С3 and С28 are completely shifted to the weak-field region (to 88.21 and 67.32 ppm, respectively) with respect to betulin. Using the potentiometric titration method, the product of acidity constants K₁ and K₂ of a solution of the betulin disulfate H⁺ form has been found to be 3.86 × 10^–6 ± 0.004. It has been demonstrated by the thermal analysis that betulin and the betulin disulfate sodium salt are stable at temperatures of up to 240 and 220 °C, respectively. The density functional theory method has been used to obtain data on the most stable conformations, molecular electrostatic potential, frontier molecular orbitals, and mulliken atomic charges of betulin and betulin disulfate and to calculate the spectral characteristics of initial and sulfated betulin, which agree well with the experimental data.     

Reinforcing properties of ethanol in neonatal rats: Involvement of the opioid system.

Toward understanding why infant rats ingest high levels of ethanol without initiation procedures, the authors tested effects of mu and kappa receptor antagonists on ethanol reinforcement in neonatal rats. After an intracisternal injection of CTOP (mu antagonist), nor-Binaltorphimine (kappa antagonist), or saline, newborn (3-hr-old) rats were given conditioning pairings of an odor with intraorally infused ethanol or a surrogate nipple with ethanol administered intraperitoneally (to minimize ethanol's gustatory attributes). In each case, these opioid antagonists reduced or eliminated ethanol's reinforcement effect. The same effects occurred with saccharin as the reinforcer in olfactory conditioning. The results imply that activation of mu and kappa receptors, apparently acting jointly, is necessary for reinforcement or that antagonists of this activity impair basic conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and characterization of C60‐based composites of amphiphilic N‐vinylpyrrolidone/triethylene glycol dimethacrylate copolymers

It was found that under mixing of aqueous solutions of copolymers and toluene solutions of C₆₀ two types of polymer composites can be produced with different matrix structure, the fullerene content and an aggregation degree. The dimethacrylate enriched macromolecules migrate to toluene and the VP units enriched copolymer chains remain in water to form copolymer micelles and their aggregates in these media that solubilize and encapsulate the fullerene. The structure and properties of obtained polymer composites were studied by GPC with dual detection (RI and MALLS), FT‐IR, WAXS and SAXS methods. It is shown that in a composite based on N‐vinylpyrrolidone copolymer isolated from toluene the fullerene form larger particles, compare to that isolated from water. According to SAXS, the fullerene particles in a solid copolymer are organized in spherical objects with fine coil‐like structure. The stability of the composites in water, ethanol, and chloroform was shown to depend on the original polymer matrix structure and on copolymer/fullerene ratio. POLYM. COMPOS., 35:1362–1371, 2014. © 2013 Society of Plastics Engineers     

Implementation of the Contensou–Erismann tangent forces model in the Hertz contact problem

In frame of the Hertz contact problem, an approximate model to compute resulting wrench of the dry friction tangent forces is built up. The wrench consists of the total friction force and the drilling friction torque. An approach under consideration develops in a natural way the contact model constructed earlier. The dry friction force and torque are integrated over the contact elliptic area. Generally, an analytic computation of the integrals mentioned leads to the cumbersome calculation, tens of terms, including rational functions depending in turn on complete elliptic integrals. To implement the elastic bodies contact interaction computer model fast enough, one builds up an approximate model in the way initially proposed by Contensou.     

C60 and C60-arginine aqueous solutions: In vitro toxicity and structural study

Abstract

Small-angle X-ray and neutron scattering was applied for the structural characterization of aggregates in water dispersions of fullerene C₆₀ prepared by dialysis method and its conjugate with amino acid arginine. Two compounds are also compared with respect to their toxic properties. Experiments on the cytotoxicity of these systems on the A549, HepG2 and HeLa cells showed no toxic effects of the dispersions.