157 research outputs found
Demonstration of chronometric leveling using transportable optical clocks beyond laser coherence limit
Optical clock network requires the establishment of optical frequency
transmission link between multiple optical clocks, utilizing narrow linewidth
lasers. Despite achieving link noise levels of 10, the final accuracy
is limited by the phase noise of the clock laser. Correlation spectroscopy is
developed to transmit frequency information between two optical clocks
directly, enabling optical clock comparison beyond the phase noise limit of
clock lasers, and significantly enhancing the measurement accuracy or shorten
the measurement time. In this letter, two compact transportable
Ca clocks are employed to accomplish the correlation
spectroscopy comparison, demonstrating an 10 cm level measurement accuracy of
chronometric leveling using a mediocre clock laser with linewidth of 200 Hz.
The relative frequency instability reaches ,
which is about 20 times better than the result with Rabi spectroscopy using the
same clock laser. This research greatly reduces the harsh requirements on the
performance of the clock laser, so that an ordinary stable-laser can also be
employed in the construction of optical clock network, which is essential for
the field applications, especially for the chronometric leveling
Immunohistochemical Evaluation of Histological Change in a Chinese Milroy Disease Family With Venous and Skin Abnormities
Background: Milroy disease (MD) is rare and autosomal dominant resulting from mutations of the vascular endothelial growth factor receptor-3 (VEGFR-3 or FLT4), which leads to dysgenesis of the lymphatic system.Methods: Here we report a Chinese MD family with 2 affected members of two generations. We identified the mutation of c.3075G>A in one allele of FLT4 in Chinese population firstly. The father and child presented lymphedema under knees both. Unfortunately, the child was premature delivered for a car accident of the mother and then died of asphyxia. Then we gathered the tissue of the lower-limb from the child with permission from the parents and ethic committee. We stained the tissue with lymphatic marker D2-40 and hematoxylin-eosin to explore the histological changes. Afterwards, we compared the results with a normal child who unfortunately died of premature delivery also.Results: It is firstly identified the mutation of FLT4: c.3075G>A in Chinese population, and the mutation Inherited in the lineage. The histological evaluation indicated: (1) The number of lymphatic vessels decreased; (2) The morphology and structure of lymphatic vessels was abnormal. And what is added to our knowledge: (1) Capillary hyperemia and phlebectasia is severe; (2) Vascular malformations; (3) The number of vascular endothelial cells and vascular smooth muscle cells decreased; (4) Large sheets of epidermis desquamated; (5) The numbers of cutaneous appendages reduced in MD.Conclusions: Based on the new findings, we assume that mutation of FLT4 not only affect the lymphogenesis, but also the angiogenesis, and epidermis structure
The COP9 signalosome reduces neuroinflammation and attenuates ischemic neuronal stress in organotypic brain slice culture model
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