Inhibition of prefrontal protein synthesis following recall does not disrupt memory for trace fear conditioning

Background  

The extent of similarity between consolidation and reconsolidation is not yet fully understood. One of the differences noted is that not every brain region involved in consolidation exhibits reconsolidation. In trace fear conditioning, the hippocampus and the medial prefrontal cortex (mPFC) are required for consolidation of long-term memory. We have previously demonstrated that trace fear memory is susceptible to infusion of the protein synthesis inhibitor anisomycin into the hippocampus following recall. In the present study, we examine whether protein synthesis inhibition in the mPFC following recall similarly results in the observation of reconsolidation of trace fear memory.     

Lamellar-non-lamellar phase transitions in synthetic glycoglycerolipids studied by time-resolved X-ray diffraction

The phase sequences of eight fully hydrated synthetic, stereochemically pure glycoglycerolipids with saturated alkyl chains 12-18 carbon atoms long and a glucose, galactose or mannose head group are followed in real time during heating and cooling scans using synchrotron X-ray diffraction. One of them, 1,2-di-O-hexadecyl-3-O-β-D-glucosyl-sn-glycerol, has been characterized by X-ray diffraction for the first time. A summary of the lamellar-non-lamellar transition sequences and reversibility for all eight glycoglycerolipids studied is provided. It includes also observations of intermediate phases, previously not detected. Lattice parameters of the various phases have been determined as functions of chain length in monoglucosides. While the repeat periods of the lamellar phases increase linearly with chain length, an anomalously high lattice spacing of the inverted hexagonal phase is observed at a chain length of 14 carbon atoms. This maximum coincides with the disappearance of the cubic phases from the phase sequence upon chain elongation from 12 to 14 carbon atoms. It thus appears that the expanded H_II phase in 14-Glc retains structural characteristics of the anticipated cubic phases. Upon heating to high temperatures, its high lattice spacing gradually approaches that of the 'normal' hexagonal phase. A direct transition from lamellar subgel to inverted hexagonal phase has been observed to proceed without intermediate structures, but with an extended phase coexistence region, in 1,2-di-O-tetradecyl-3-O-β-D-galactosyl-sn-glycerol and 1,2-di-O-octadecyl-3-O-β-D-galactosyl-sn-glycerol. This transition is not reversible on cooling when lamellar phases skipped in the heating scan intervene. By contrast, the direct lamellar gel-inverted hexagonal phase transitions are fully reversible with minor or absent temperature hysteresis.     

Calorimetric investigation of complex reaction courses in organic chemistry

Acetylation of different hexanediols as a complex reaction has been investigated by calorimetry. The calorimetric curves demonstrate that the reaction rate depends on the molecular structure. In case of 1,6- and 2,5-hexanediols, the activation parameters have been obtained by nonlinear evaluation procedures with the program TA-kin v3.3. The kinetic results show, that the formation of the diester is characterized by higher activation energies than that of the monoester.     

A Uniqueness Result for a Model for Mixtures in the Absence of External Forces and Interaction Momentum

We consider a continuum model describing steady flows of a miscible mixture of two fluids. The densities ϱ _i of the fluids and their velocity fields u ⁽ⁱ⁾ are prescribed at infinity: ϱ _i |_∞ = ϱ _i∞ > 0, u ⁽ⁱ⁾|∞ = 0. Neglecting the convective terms, we have proved earlier that weak solutions to such a reduced system exist. Here we establish a uniqueness type result: in the absence of the external forces and interaction terms, there is only one such solution, namely ϱ _i ≡ ϱ _i∞, u ⁽ⁱ⁾ ≡ 0, i = 1, 2. This work was supported by the SFB 611 at the University of Bonn and the European HYKE network (contract no. HPRN-CT-2002-00282). The third author was also supported by the project CSF 201/03/0934, and by MSM 0021620839.     

Heisenberg groups—A unifying structure of signal theory, holography and quantum information theory

Vector fields in three-space admit bundles of internal variables such as a Heisenberg algebra bundle. Information transmission along field lines of vector fields is described by a wave linked to the Schrödinger representation in the realm of time-frequency analysis. The preservation of local information causes geometric optics and a quantization scheme. A natural circle bundle models quantum information visualized by holographic methods. Features of this setting are applied to magnetic resonance imaging.     

Enzymatic and chemical hydrolysis of poly(ethylene terephthalate) fabrics

Alkaline and enzymatic hydrolyzes of poly(ethylene terephthalate) fabrics (PET) were mechanistically compared based on released degradation products (HPLC‐UV‐RI) and changes in surface properties [hydrophilicity, cationic dyeing, X‐ray photoelectron spectroscopy (XPS)]. Enzymatic hydrolysis led to an increase in the amount of hydroxyl and carboxyl groups on the surface resulting in an enhanced water absorption and dyeability. Enzymes partially adsorbed to PET fabrics during hydrolysis were completely removed by subsequent extraction according to XPS analysis. In contrast to the enzyme treatment, alkaline hydrolysis did not lead to an increase of hydroxyl and acid groups according to XPS while both treatments caused a substantial increase in hydrophilicity and were more effective on amorphous fibers. Alkaline hydrolysis led to a greater increase in the K/S value after cationic dyeing due to enlarged surface area. Consequently, ESEM‐images demonstrated that alkaline treatment drastically affected the surface morphology of the polymer resulting in crater‐like structures of the fibers, whereas after enzymatic treatment the morphology of the fibers remained unchanged. To reach similar benefits in hydrophilicity, drastically higher amounts of degradation products were released during alkaline hydrolysis as also indicated by >6% weight loss compared to <1% after enzyme treatment. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6435–6443, 2008