30 research outputs found
NanoglassâNanocrystal Composite - a Novel Material Class for Enhanced StrengthâPlasticity Synergy
The properties of a material can be engineered by manipulating its atomic and chemical architecture. Nanoglasses which have been recently invented and comprise nanosized glassy particles separated by amorphous interfaces, have shown promising properties. A potential way to exploit the structural benefits of nanoglasses and of nanocrystalline materials is to optimize the composition to obtain crystals forming within the glassy particles. Here, a metastable Feâ10 at% Sc nanoglass is synthesized. A complex hierarchical microstructure is evidenced experimentally at the atomic scale. This bulk material comprises grains of a FeSc amorphous matrix separated by an amorphous interfacial network enriched and likely stabilized by hydrogen, and propertyâenhancing pureâFe nanocrystals selfâassembled within the matrix. This composite structure leads a yield strength above 2.5 GPa with an exceptional quasiâhomogeneous plastic flow of more than 60% in compression. This work opens new pathways to design materials with even superior properties
Capacitively Coupled Silicon-Organic Hybrid Modulator for 200 Gbit/s PAM-4 Signaling
We demonstrate capacitively coupled silicon-organic hybrid (SOH) modulator with a Ï-voltage-length product of 1.3 V mm and 3 dB EO bandwidth exceeding 65 GHz. The modulator is used for 200 Gbit/s (100 GBd) PAM-4 signaling
Conscious perception and the modulatory role of dopamine: no effect of the dopamine D2 agonist cabergoline on visual masking, the attentional blink, and probabilistic discrimination
Rationale
Conscious perception is thought to depend on global amplification of sensory input. In recent years, striatal dopamine has been proposed to be involved in gating information and conscious access, due to its modulatory influence on thalamocortical connectivity.
Objectives
Since much of the evidence that implicates striatal dopamine is correlational, we conducted a double-blind crossover pharmacological study in which we administered cabergolineâa dopamine D2 agonistâand placebo to 30 healthy participants. Under both conditions, we subjected participants to several well-established experimental conscious-perception paradigms, such as backward masking and the attentional blink task.
Results
We found no evidence in support of an effect of cabergoline on conscious perception: key behavioral and event-related potential (ERP) findings associated with each of these tasks were unaffected by cabergoline.
Conclusions
Our results cast doubt on a causal role for dopamine in visual perception. It remains an open possibility that dopamine has causal effects in other tasks, perhaps where perceptual uncertainty is more prominent
Identification of a 44 kDa protein localized within the endoplasmic reticulum of Trypanosoma brucei brucei
Immunoaffinity chromatography and gel electophoresis were used to isolate a 44 kDa protein that was bound to a 72 kDa chaperone in Trypanosoma brucei brucei. A polyclonal antiserum to the 44 kDa protein was raised in rats and employed in conjunction with chromatography using DEAE-cellulose, Sephacryl S-300, and hydroxyapatite to purify the protein from membranes of bloodstream forms of the trypanosomes. Immunoblot analysis using this antiserum revealed a protein doublet of 44/45 kDa in T. b brucei and a single protein band of 53 kDa in almost equivalent amounts throughout the life-cycle stages of T. congolense. Indirect immunofluorescence using affinity-purified antibodies specific for the 44 kDa protein showed labelling of the perinuclear area and reticular system extending throughout the parasites, suggesting that this protein was located in the endoplasmic reticulum. Localization of the 44 kDa molecule in the endoplasmic reticulum was confirmed by immunoelectron microscopy. Protease protection experiments demonstrated that the epitopes bound by antibody were buried within the membrane or towards the lumenal face of the endoplasmic reticulum. Ruthenium Red overlay of nitrocellulose blots containing the 44/45 kDa doublet suggested that the molecules have the potential to bind calcium. The N-terminal amino acid sequence of the 44 kDa protein showed no sequence similarity to any proteins in the database