8 research outputs found
Extended depth of field imaging for high speed object analysis
A high speed, high-resolution flow imaging system is modified to achieve extended depth of field imaging. An optical distortion element is introduced into the flow imaging system. Light from an object, such as a cell, is distorted by the distortion element, such that a point spread function (PSF) of the imaging system is invariant across an extended depth of field. The distorted light is spectrally dispersed, and the dispersed light is used to simultaneously generate a plurality of images. The images are detected, and image processing is used to enhance the detected images by compensating for the distortion, to achieve extended depth of field images of the object. The post image processing preferably involves de-convolution, and requires knowledge of the PSF of the imaging system, as modified by the optical distortion element
Observation of Flat Band and Van Hove Singularity in Non-superconducting Nitrogen-doped Lutetium Hydride
Hydrogen-rich materials offer a compelling avenue towards room temperature
superconductivity, albeit under ultra-high pressure. However, the experimental
investigation of the electronic band structure remains elusive, due to the
inherent instability of most of the hydrogen-rich materials upon pressure
release. Very recently, nitrogen-doped lutetium hydride was claimed to host
room temperature superconductivity under near ambient pressure but was
disproven by following works. Upon decompression, nitrogen doped lutetium
hydride manifests a stable metallic phase with dark blue color. Moreover, high
temperature superconductivity has been reported in lutetium hydrides Lu4H23
(~71 K) under around 200 GPa. These properties engender an unprecedented
opportunity, allowing for the experimental investigation of the electronic band
structure intrinsic to hydrogen-rich material. In this work, using angle
resolved photoemission spectroscopy to investigate the non-superconducting
nitrogen doped lutetium hydride, we observed significant flat band and Van Hove
singularity marginally below the Fermi level. These salient features,
identified as critical elements, proffer potential amplifiers for the
realization of heightened superconductivity, as evidenced by prior research.
Our results not only unveil a confluence of potent strong correlation effects
and anisotropy within the Lu-H-N compound, but also provide a prospect for
engineering high temperature superconductivity through the strategic
manipulation of flat band and the VHS, effectively tailoring their alignment
with the Fermi energy.Comment: 26 pages, 9 figure
As Epidermal Stem Cells Age they do not Substantially Change their Characteristics
In this study, we ask the basic question: do stem cells age? We demonstrated that epidermal stem cells isolated from neonatal mice had the capacity to form multiple cell lineages during development. Here we demonstrate the cell lineages are clonal, and that epidermal stem cells isolated from the footpad epithelium of old mice have similar capabilities. Using Hoechst dye exclusion and cell size, we isolated viable homogenous populations of epidermal stem and transit-amplifying (TA) cells from GFP-transgenic mice, and injected these cells into 3.5-d blastocysts. Only the stem-injected blastocysts produced mice with GFP+ cells in their tissues. Furthermore, aged and young stem cells showed similar gene and protein expression profiles that showed some differences from the TA cell profiles. These data suggest that there may be a fundamental difference between somatic stem and TA cells, and that an epidermal stem cell placed in a developmental environment can alter its fate determination no matter what its age