Results 71 to 80 of about 6,778,249 (313)

Shear free solutions in general relativity theory [PDF]

open access: yes, 2011
The Goldberg-Sachs theorem is an exact result on shear-free null geodesics in a vacuum spacetime. It is compared and contrasted with an exact result for pressure-free matter: shear-free flows cannot both expand and rotate.
G. Ellis
semanticscholar   +1 more source

Gut microbiome and aging—A dynamic interplay of microbes, metabolites, and the immune system

open access: yesFEBS Letters, EarlyView.
Age‐dependent shifts in microbial communities engender shifts in microbial metabolite profiles. These in turn drive shifts in barrier surface permeability of the gut and brain and induce immune activation. When paired with preexisting age‐related chronic inflammation this increases the risk of neuroinflammation and neurodegenerative diseases.
Aaron Mehl, Eran Blacher
wiley   +1 more source

The Relativity Theory of Plane Waves

open access: yes, 1926
Weyl has shown that any gravitational wave of small amplitude may be regarded as the result of the superposition of waves of three types, viz.: (i) longitudinal-longitudinal; (ii) longitudinal-transverse; (iii) transverse-transverse.
O. R. Baldwin, G. B. Jeffery
semanticscholar   +1 more source

A methionine‐lined active site governs carbocation stabilization and product specificity in a bacterial terpene synthase

open access: yesFEBS Letters, EarlyView.
This study reveals a unique active site enriched in methionine residues and demonstrates that these residues play a critical role by stabilizing carbocation intermediates through novel sulfur–cation interactions. Structure‐guided mutagenesis further revealed variants with significantly altered product profiles, enhancing pseudopterosin formation. These
Marion Ringel   +13 more
wiley   +1 more source

General Covariance and Background Independence in Quantum Gravity [PDF]

open access: yes, 2012
The history of general relativity suggests that in absence of experimental data, constructing a theory on philosophical first principles can lead to a very useful theory as well as to ground-breaking insights about physical reality.
Bärenz, Manuel
core   +1 more source

An isoform of 14‐3‐3 protein regulates transbilayer lipid movement at the plasma membrane

open access: yesFEBS Letters, EarlyView.
Loss of 14‐3‐3ζ in CHO cells confers resistance to exogenous phosphatidylserine (PS) and impairs endocytosis‐independent inward flip‐flop of fluorescent PS at the plasma membrane. RNAi‐mediated knockdown reproduces this defect, while no additive effect is seen in ATP11C‐deficient cells.
Akiko Yamaji‐Hasegawa   +3 more
wiley   +1 more source

Theory of Relativity [PDF]

open access: yesJournal of General Internal Medicine, 2013
You’ll be one of those people who gets used to the long hours. You’ll beat the traffic going in and coming home. Weather will not stop you. You’ll know every shade of night. You’ll know the facts and when and how to share them. You’ll take call and look like you slept in it or stepped in it. You’ll know how to get the blood out.
openaire   +1 more source

pH‐mediated activation of the lysosomal arginine sensor SLC38A9

open access: yesFEBS Letters, EarlyView.
Cells monitor nutrient levels via the lysosomal transporter SLC38A9 to activate the mechanistic target of rapamycin complex 1 (mTORC1). This study reveals that SLC38A9 function is regulated by pH. We identified histidine 544 as a critical pH sensor that undergoes conformational changes to control amino acid efflux from lysosomes; therefore, it ...
Xuelang Mu, Ampon Sae Her, Tamir Gonen
wiley   +1 more source

A tale of analogies: a review on gravitomagnetic effects, rotating sources, observers and all that

open access: yesJournal of Physics Communications, 2023
Gravitoelectromagnetic analogies are somewhat ubiquitous in General Relativity, and they are often used to explain peculiar effects of Einstein’s theory of gravity in terms of familiar results from classical electromagnetism.
Matteo Luca Ruggiero, Davide Astesiano
doaj   +1 more source

Why special relativity should not be a template for a fundamental reformulation of quantum mechanics [PDF]

open access: yes, 2005
In a comparison of the principles of special relativity and of quantum mechanics, the former theory is marked by its relative economy and apparent explanatory simplicity. A number of theorists have thus been led to search for a small number of postulates
Brown, Harvey R.   +1 more
core   +1 more source

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