74,921 articles mezi dny 1.12.2019 a 31.12.2020

Traditional Ghanaian medicines show promise against tropical diseases

The discovery of new drugs is vital to achieving the eradication of neglected tropical diseases (NTDs) in Africa and around the world. Now, researchers have identified traditional Ghanaian medicines which work in the lab against schistosomiasis, onchocerciasis and lymphatic filariasis, three diseases endemic to Ghana.

Stretching diamond for next-generation microelectronics

Diamond is the hardest material in nature. It also has great potential as an excellent electronic material. A research team has demonstrated for the first time the large, uniform tensile elastic straining of microfabricated diamond arrays through the nanomechanical approach. Their findings have shown the potential of strained diamonds as prime candidates for advanced functional devices in...

Spontaneous robot dances highlight a new kind of order in active matter

Researchers have proposed a new principle by which active matter systems can spontaneously order, without need for higher level instructions or even programmed interaction among the agents. And they have demonstrated this principle in a variety of systems, including groups of periodically shape-changing robots called 'smarticles.'

Land subsidence 'will affect almost fifth of global population'

Unesco warns of urban centres sinking because of unsustainable farming and groundwater extraction Subsidence, or the gradual sinking of land, could affect 19% of the world’s population by 2040, according to new research funded by Unesco.If no action is taken, human activity, combined with drought and rising sea levels exacerbated by global heating, could put many of the world’s coastal cities...

Stretching diamond for next-generation microelectronics

Diamond is the hardest material in nature. But out of many expectations, it also has great potential as an excellent electronic material. A joint research team led by City University of Hong Kong (CityU) has demonstrated for the first time the large, uniform tensile elastic straining of microfabricated diamond arrays through the nanomechanical approach. Their findings have shown the potential of...

The Guardian view on Covid science: cooperation, not just competition | Editorial

Scientists should follow the example of the Chinese professor whose selfless decision to share his breakthrough led to the medical miracle of a vaccineThere are many people deserving of praise for selfless acts during the past 12 months. But one person whose act of scientific generosity ought to be remembered is Zhang Yongzhen. The scientist, who works out of the Shanghai Public Health Clinical...

A rechargeable zinc-air battery based on zinc peroxide chemistry

Rechargeable alkaline zinc-air batteries promise high energy density and safety but suffer from the sluggish 4 electron (e–)/oxygen (O2) chemistry that requires participation of water and from the electrochemical irreversibility originating from parasitic reactions caused by caustic electrolytes and atmospheric carbon dioxide. Here, we report a zinc-O2/zinc peroxide (ZnO2) chemistry that...

A tripartite mechanism catalyzes Mad2-Cdc20 assembly at unattached kinetochores

During cell division, kinetochores couple chromosomes to spindle microtubules. To protect against chromosome gain or loss, kinetochores lacking microtubule attachment locally catalyze association of the checkpoint proteins Cdc20 and Mad2, which is the key event in the formation of a diffusible checkpoint complex that prevents mitotic exit. We elucidated the mechanism of kinetochore-catalyzed...

Achieving large uniform tensile elasticity in microfabricated diamond

Diamond is not only the hardest material in nature, but is also an extreme electronic material with an ultrawide bandgap, exceptional carrier mobilities, and thermal conductivity. Straining diamond can push such extreme figures of merit for device applications. We microfabricated single-crystalline diamond bridge structures with ~1 micrometer length by ~100 nanometer width and achieved sample-wide...

Aerosol invigoration of atmospheric convection through increases in humidity

Cloud-aerosol interactions remain a major obstacle to understanding climate and severe weather. Observations suggest that aerosols enhance tropical thunderstorm activity; past research, motivated by the importance of understanding aerosol impacts on clouds, has proposed several mechanisms that could explain that observed link. We find that high-resolution atmospheric simulations can reproduce the...

Airway stem cells sense hypoxia and differentiate into protective solitary neuroendocrine cells

Neuroendocrine (NE) cells are epithelial cells that possess many of the characteristics of neurons, including the presence of secretory vesicles and the ability to sense environmental stimuli. The normal physiologic functions of solitary airway NE cells remain a mystery. We show that mouse and human airway basal stem cells sense hypoxia. Hypoxia triggers the direct differentiation of these stem...

CDC20 assists its catalytic incorporation in the mitotic checkpoint complex

Open (O) and closed (C) topologies of HORMA-domain proteins are respectively associated with inactive and active states of fundamental cellular pathways. The HORMA protein O-MAD2 converts to C-MAD2 upon binding CDC20. This is rate limiting for assembly of the mitotic checkpoint complex (MCC), the effector of a checkpoint required for mitotic fidelity. A catalyst assembled at kinetochores...

Clocks, cancer, and chronochemotherapy

The circadian clock coordinates daily rhythmicity of biochemical, physiologic, and behavioral functions in humans. Gene expression, cell division, and DNA repair are modulated by the clock, which gives rise to the hypothesis that clock dysfunction may predispose individuals to cancer. Although the results of many epidemiologic and animal studies are consistent with there being a role for the clock...

Evolution of fold switching in a metamorphic protein

Metamorphic proteins switch between different folds, defying the protein folding paradigm. It is unclear how fold switching arises during evolution. With ancestral reconstruction and nuclear magnetic resonance, we studied the evolution of the metamorphic human protein XCL1, which has two distinct folds with different functions, making it an unusual member of the chemokine family, whose members...

Interactions between nascent proteins translated by adjacent ribosomes drive homomer assembly

Accurate assembly of newly synthesized proteins into functional oligomers is crucial for cell activity. In this study, we investigated whether direct interaction of two nascent proteins, emerging from nearby ribosomes (co-co assembly), constitutes a general mechanism for oligomer formation. We used proteome-wide screening to detect nascent chain–connected ribosome pairs and identified...

Low rattling: A predictive principle for self-organization in active collectives

Self-organization is frequently observed in active collectives as varied as ant rafts and molecular motor assemblies. General principles describing self-organization away from equilibrium have been challenging to identify. We offer a unifying framework that models the behavior of complex systems as largely random while capturing their configuration-dependent response to external forcing. This...

Nanoscale control of internal inhomogeneity enhances water transport in desalination membranes

Biological membranes can achieve remarkably high permeabilities, while maintaining ideal selectivities, by relying on well-defined internal nanoscale structures in the form of membrane proteins. Here, we apply such design strategies to desalination membranes. A series of polyamide desalination membranes—which were synthesized in an industrial-scale manufacturing line and varied in processing...