Isolation of eukaryotic ribosomal proteins. Purification and characterization of the 40 S ribosomal subunit proteins Sa, Sc, S3a, S3b, S5', S9, S10, S11, S12, S14, S15, S15', S16, S17, S18, S19, S20, S21, S26, S27', and S29

The proteins of the small subunit of rat liver ribosomes were separated into five main groups by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5. Twenty-one proteins (Sa, Sc, S3a, S3b, S5', S9, S10, S11, S12, S14, S15, S15', S16, S17, S18, S19, S20, S21, S26, S27', and S29) were isolated from three groups (A40, C40, and D40) by ion exchange chromatography on DEAE-cellulose, carboxymethylcellulose, and phosphocellulose and by filtration through Sephadex. The amount of protein obtained varied from 0.1 to 11 mg. Six of the proteins (S5', S10, S11, S18, S19, and S27') had no detectable contamination; the impurities in the others were no greater than 9%. The molecular weight of the proteins was estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate; the amino acid composition was determined.     

Intrastriatal infusion of lisuride--a potential treatment for Parkinson's disease? Behavioral and autoradiographic studies in 6-OHDA lesioned rats

The present study examined the effect of chronic intrastriatal infusion of the dopamine receptor agonist lisuride on apomorphine-induced rotational behaviour and on D2-dopamine receptors in rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal dopaminergic pathway. The completeness of the lesion of the right ascending nigrostriatal dopaminergic pathway was confirmed by apomorphine-induced rotation and [3H]-mazindol autoradiography. The intrastriatal infusion of lisuride (0.5 microgram/h) into the lesioned striatum for 2 weeks induced an immediate but temporary spontaneous contralateral rotation and a reduction of apomorphine-induced rotation of 47.2% relative to pre-lisuride infusion. The density of D2-receptors in the lisuride-infused striatum was significantly decreased by 40% relative to vehicle-infused 6-OHDA lesioned rats. The level of D2-dopamine receptors returned to normal levels 3 weeks after the termination of lisuride infusion. These results show that the intrastriatal infusion of lisuride reverses the behavioural and D2-dopamine receptor changes present in the 6-OHDA lesion rat model of Parkinson's disease.     

Creating heralded hyper-entangled photons using Rydberg atoms

Entangled photon pairs are a fundamental component for testing the foundations of quantum mechanics, and for modern quantum technologies such as teleportation a...     

Growth of silver nano-particle embedded in tellurite glass: Interaction between localized surface plasmon resonance and Er ions

In this paper we show a systematic study of the growth of silver nano-particles (NPs) embedded in an Erbium-doped tellurite glass with annealing time, aiming to a photoluminescence enhancement. The results indicate an improved or quenching of the photoluminescence due to an energy transfer mechanism in the coupling between NP’s electric dipoles and Er⁺³ transitions (⁴S_3/2 → ⁴I_15/2, ⁴F_9/2 → ⁴I_15/2 and ⁴I_13/2 → ⁴I_15/2).     

Photophysics of Two-Dimensional Perovskites—Learning from Metal Halide Substitution

2D perovskites offers a rich playing field to explore exciton physics and they possess a great potential for a variety of opto-electronic applications. Whilst their photophysics shows intricate interactions of excitons with the lattice, most reports have so far relied on single compound studies. With the exception of variations of the organic spacer cations, the effect of constituent substitution on the photophysics and the nature of emitting species, in particular, have remained largely under-explored. Here PEA₂PbBr₄, PEA₂PbI₄, and PEA₂SnI₄ (where PEA stands for phenylethylammonoium) are studied through a variety of optical spectroscopy techniques to reveal a complex set of excitonic transitions at low temperature. Weak high-energy features are attributed to vibronic transitions breaking Kasha's, for which the responsible phonons cannot be accessed through simple Raman spectroscopy. Bright peaks at lower energy are due to two distinct electronic states, of which the upper is a convolution of the free exciton and a localized dark state and the lower is attributed to recombination involving shallow defects. This study offers deeper insights into the photophysics of 2D perovskites through compositional substitution and highlights critical limits to the communities’ current understanding of processes in these compounds.     

Advancing Multicomponent Strategies to Macrobicyclic Peptides

Macrocyclization of peptides is typically used to fix specific bioactive conformations and improve their pharmacological properties. Recently, macrobicyclic peptides have received special attention owing to their capacity to mimic protein structures or be key components of peptide-drug conjugates. Here, we describe the development of novel synthetic strategies for two distinctive types of peptide macrobicycles. A multicomponent macrocyclo-dimerization approach is introduced for the production of interconnected β-turns, allowing two macrocyclic rings to be formed and dimerized in one pot. Also, an on-resin double stapling strategy is described for the assembly of lactam-bridged macrobicycles with stable tertiary folds.     

Permeability Comparison of Natural and Artificial Pinus Radiata Forest Litters

Forest litter flammability metrics have been extensively studied under laboratory conditions, but little research has been conducted in quantifying the difference between artificially reconstructed litters and natural litters. In order to assess the fire spread behaviour of natural litter beds, a sampling method was designed to obtain almost unperturbed radiata pine litters. As permeability is expected to affect flammability, this property was used for comparison between natural and artificially reconstructed litters. The pressure drop of airflow through undisturbed litter samples was measured in the vertical and horizontal direction for different flow velocities. The permeability of the specimens was obtained by fitting experimental values to the Forchheimer equation. It was found that for natural litter samples the horizontal permeability is almost unaffected by bulk density, while the vertical permeability is a decaying linear function of bulk density. It was further found that the permeability of artificially reconstructed litter samples depends exponentially on the bulk density of the sample. Surface to volume ratio, density and porosity of both types of litter are also informed, and qualitative comparison between them is given. Surface to volume ratio as well as density and porosity were notably different between natural and reconstructed litters.