178,567 research outputs found
Highly efficient optogenetic cell ablation in C. elegans using membrane-targeted miniSOG.
The genetically encoded photosensitizer miniSOG (mini Singlet Oxygen Generator) can be used to kill cells in C. elegans. miniSOG generates the reactive oxygen species (ROS) singlet oxygen after illumination with blue light. Illumination of neurons expressing miniSOG targeted to the outer mitochondrial membrane (mito-miniSOG) causes neuronal death. To enhance miniSOG's efficiency as an ablation tool in multiple cell types we tested alternative targeting signals. We find that membrane targeted miniSOG allows highly efficient cell killing. When combined with a point mutation that increases miniSOG's ROS generation, membrane targeted miniSOG can ablate neurons in less than one tenth the time of mito-miniSOG. We extend the miniSOG ablation technique to non-neuronal tissues, revealing an essential role for the epidermis in locomotion. These improvements expand the utility and throughput of optogenetic cell ablation in C. elegans
The radiation properties of an accretion disk with a non-zero torque on its inner edge
The structure of the inner edge of the accretion disk around a black hole can
be altered, if the matter inside the marginally stable orbit is magnetically
connected to the disk. In this case, a non-zero torque is exerted on its inner
edge, and the accretion efficiency can be much higher than that in
the standard accretion disk model. We explore the radiation properties of an
accretion disk at its sonic point around a black hole with a time-steady torque
exerted on the inner edge of the disk. The local structure of the accretion
flow at the sonic point is investigated in the frame of general relativity. It
is found that the accretion flow will be optically thin at its sonic point for
most cases, if the additional accretion efficiency caused by
the torque is as high as 10 %. The results imply that the variable torque
may trigger transitions of the flow between different accretion types.Comment: 6 pages, to appear in PASJ, Vol. 55, No. 1 (February 25, 2003
Existence of log canonical closures
Let be a projective morphism of normal varieties and
a dlt pair. We prove that if there is an open set , such that
has a good minimal model over and the images of
all the non-klt centers intersect , then has a good minimal
model over . As consequences we show the existence of log canonical
compactifications for open log canonical pairs, and the fact that the moduli
functor of stable schemes satisfies the valuative criterion for properness
- …