Cholinergic receptor blockade impairs spatial localization by use of distal cues in the rat.

Studied spatial localization in the Morris water maze. 30 male Long-Evans hooded rats were required to escape from cool water by finding a submerged, invisible platform located at a fixed place. The start point randomly varied, and there were no local cues. After training, the platform was moved. Six Ss subjected to central cholinergic receptor blockade with atropine sulfate were compared with normal Ss and with 6 Ss receiving peripheral cholinergic blockade with atropine methylnitrate. The controls were a group of blind Ss and Ss for which the platform was moved from trial to trial. Results show that controls and the atropine methylnitrate Ss used a spatial mapping strategy to locate the platform. The atropine sulfate-treated Ss adopted a search strategy like that of the blind Ss and Ss for which the platform was randomly moved. Results support the idea that central cholinergic systems are important for spatial mapping, which demands the use of distal visual cues. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the prebiotic synthesis of ribonucleotides: photoanomerisation of cytosine nucleosides and nucleotides revisited

Recent work has emphasised the importance of D-ribose aminooxazoline 1 in the synthesis of cytidine ribonucleosides under potentially prebiotic conditions. Upon treatment with cyanoacetylene, 1 is transformed into alpha-D-cytidine (alpha-2), and if an efficient means of anomerising this nucleoside or a derivative thereof were to be found, then the synthesis of one of the key beta-D-nucleosides required to make RNA would be realised. Photoanomerisation of alpha-2 has previously been described, but the yield was extremely low. Therefore, the present study was initiated to determine whether this low yield was the result of a low conversion or competing reaction pathways.     

Ultrafast vibrations of gold nanorings

We investigate the vibrational modes of gold nanorings on a silica substrate with an ultrafast optical technique. By comparison with numerical simulations, we identify several resonances in the gigahertz range associated with axially symmetric deformations of the nanoring and substrate. We elucidate the corresponding mode shapes and find that the substrate plays an important role in determining the mode damping. This study demonstrates the need for a plasmonic nano-optics approach to understand the optical excitation and detection mechanisms for the vibrations of plasmonic nanostructures.     

Soft interactions at nanoparticles alter protein function and conformation in a size dependent manner

Weak protein-nanoparticle (NP) interactions are studied in a low binding regime as a model for the soft protein corona around nanoparticles in complex biological fluids. Noncovalent, reversible interactions between Subtilisin Carlsberg (SC) and silica NPs shows significant alteration in conformation and enzymatic activity in a NP-size dependent manner. Very weak interactions between SC and silica NPs were revealed by centrifugation-based separations and further supported by small-angle X-ray scattering, while bovine serum albumin was used as a strongly interacting reference. Secondary and tertiary structure changes of SC were studied via circular dichroism and correlated to enzymatic activity where the enzyme kinetics showed a critical role for nanoparticle size.     

Evaluation of alternatives to cautery disbudding of dairy goat kids using physiological measures of immediate and longer-term pain

We evaluated alternatives to cautery disbudding of goat kids using physiological measures of immediate and longer-term pain. Fifty Saanen doe kids were randomly assigned to 1 of 5 treatments (n = 10/treatment): (1) cautery disbudding (CAUT), (2) caustic paste disbudding (CASP), (3) liquid nitrogen disbudding (CRYO), (4) clove oil injected into the horn bud (CLOV), or (5) sham disbudding (SHAM). Serum cortisol and haptoglobin concentrations were measured from blood samples collected immediately before treatment (baseline) and at 15, 30, 60, and 120 min and then again at 6 and 24 h post-treatment. An infrared thermography camera was used to take images of the horn buds 24 h pre- and 24, 48, and 72 h post-treatment to measure skin temperature. Body weight was measured daily for 1 wk to assess weight change post-treatment. Images of the horn buds were taken at d 1, 2, and 7 and at 6 wk post-treatment to assess tissue damage and wound healing. Mean cortisol concentrations were elevated in CASP kids 1 h post-treatment relative to CAUT kids. Cortisol concentrations of CRYO kids were higher than those of CAUT kids 30 min post-treatment; concentrations for CLOV kids were similar to CAUT kids post-treatment. Mean haptoglobin concentrations were similar across treatments over time; however, CLOV kids had higher concentrations at 24 h post-treatment than all other treatments. Skin temperatures of CASP and CLOV kids were elevated relative to CAUT kids at all time points post-treatment, and all disbudded kids had skin temperatures above those of SHAM kids at 72 h post-treatment. Treatment did not influence weight gain. The CAUT kids had large, open wounds exposing bone; small scabs were still evident 6 wk post-treatment. The CASP kids had red and open, raw wounds that generated large eschars, apparent for up to 6 wk. The CRYO kids had closed, dry wounds initially, but over time lesions appeared that caused open wounds; small scabs were present 6 wk post-treatment. The CLOV kids had closed, dry wounds with blackened skin; healed skin and minimal scabs were present 6 wk post-treatment. Caustic paste and cryosurgical disbudding appeared to cause more pain compared with cautery disbudding; thus, these methods may not provide good alternatives to cautery disbudding. Clove oil appeared to cause a similar pain response as cautery disbudding and smaller wounds with earlier tissue repair; this method shows promise as an alternative to cautery disbudding.