Lin Yi - Academia.edu (original) (raw)

Papers by Lin Yi

Nature Medicine, 2003

Cells from adult bone marrow participate in the regeneration of damaged skeletal myofibers. Howev... more Cells from adult bone marrow participate in the regeneration of damaged skeletal myofibers. However, the relationship of these cells with the various hematopoietic and nonhematopoietic cell types found in bone marrow is still unclear. Here we show that the progeny of a single cell can both reconstitute the hematopoietic system and contribute to muscle regeneration. Integration of bone marrow cells into myofibers occurs spontaneously at low frequency and increases with muscle damage. Thus, classically defined single hematopoietic stem cells can give rise to both blood and muscle.

2007 Conference on Lasers and Electro-Optics - Pacific Rim, 2007

VCSEL is injection-locked to one comb component with excellent single longitude mode performance.... more VCSEL is injection-locked to one comb component with excellent single longitude mode performance. We tested the diodes without narrowly filtering the injecting comb and the VCSELs are able to sustain the injecting power. The low cost and low supply current of VCSELs furthermore reduce the complexity of amplifying the comb.

ABSTRACT In the pursuit of developing an optical lattice clock with mercury as the quantum absorb... more ABSTRACT In the pursuit of developing an optical lattice clock with mercury as the quantum absorber, we describe an experiment that produces dipole lattice trapping of neutral mercury atoms. We report on the details of an optical lattice trap with light near the predicted magic wavelength and on the implementation of a low noise detection system.

ABSTRACT form only given. Following previous work on neutral atom lattice clocks [1-4], we have p... more ABSTRACT form only given. Following previous work on neutral atom lattice clocks [1-4], we have presented work regarding a 3rd neutral atomic species, namely mercury. We have carried out absolute frequency measurements of the (6s2) 1S0 - (6s7s) 3P0 clock transition frequency in 199Hg against a Cs fountain primary reference and achieved a fractional uncertainty of 5.7 parts in 1015, nearly three orders of magnitude lower than previously measured [5].

A method to enhance the signal-to-noise ratio (SNR) of the optical frequency beat note (f b ) wit... more A method to enhance the signal-to-noise ratio (SNR) of the optical frequency beat note (f b ) with the femtosecond optical frequency comb is demonstrated. The SNR of f b and carrier-envelop offset frequency (f 0 ) can be optimized separately by using two pieces of photonic crystal fiber (PCF). While the SNR of f 0 is maintained more than 40 dB (300 kHz resolution bandwidth), the SNR of the beat note between the comb and the iodine stabilized He-Ne laser at 633 nm is promoted to 38 dB. The beat note can be directly counted by a commercial frequency counter without tracking oscillators. The frequency fluctuation due to the open-loop property of this method is below 2:8 Â 10 À15 at 1 s integration time and no obvious drift is observed at longer integration time. The open-loop fast-changing phase noise is measured to be sensitive to the acoustic noise from the environment.

ABSTRACT An optical frequency comb phase-locked on an iodine frequency stabilized diode laser at ... more ABSTRACT An optical frequency comb phase-locked on an iodine frequency stabilized diode laser at 634 nm is constructed to transfer the accuracy and stability from the optical domain to the radio frequency domain. An external-cavity diode laser is frequency-stabilized on the Doppler-free absorption signals of the hyperfine transition R(80)8-4 using the third-harmonic detection technique. The instability of the ultra-stable optical oscillator is determined to be 7\times10^{-12} by a cesium atomic clock via the optical frequency comb's mass frequency dividing technique.

We present a novel technique to phase-lock two lasers with controllable frequency difference. In ... more We present a novel technique to phase-lock two lasers with controllable frequency difference. In our setup, one sideband of a current modulated Vertical-Cavity Surface-Emitting Laser (VCSEL) is phase locked to the master laser by injection seeding, while another sideband of the VCSEL is used to phase lock the slave laser. The slave laser is therefore locked in phase with the master laser, with a frequency difference tunable up to about 35 GHz. The sideband suppression rate of the slave laser is more than 30dB at 30 µW seed power. The heterodyne spectrum between master and slave has a linewidth of less than 1 Hz. A narrow linewidth spectrum of coherent population trapping in rubidium is achieved using such beams.

High-resolution spectroscopy has been carried out on the 199 Hg 1 S 0 − 3 P 0 spin and dipole for... more High-resolution spectroscopy has been carried out on the 199 Hg 1 S 0 − 3 P 0 spin and dipole forbidden transition, where the atoms are confined in a vertical one-dimensional optical lattice trap using light at the magic wavelength. We describe various characteristics of the resulting line spectra and assess the strength of the Lamb-Dicke confinement. Through a series of absolute frequency measurements of the 199 Hg clock transition with respect to the LNE-SYRTE primary frequency standard, recorded over a 3-month period, we demonstrate a statistical fractional uncertainty of 2.5 × 10 −16 . We include details relating to the generation of ultraviolet light at three wavelengths necessary for the experiment: 253.7 nm for cooling and detection, 265.6 nm for clock transition probing, and 362.570 nm for lattice trapping, along with further aspects related to the magic wavelength evaluation.

We report on the Lamb-Dicke spectroscopy of the doubly forbidden ð6s 2 Þ 1 S 0 $ ð6s6pÞ 3 P 0 tra... more We report on the Lamb-Dicke spectroscopy of the doubly forbidden ð6s 2 Þ 1 S 0 $ ð6s6pÞ 3 P 0 transition in 199 Hg atoms confined to a vertical 1D optical lattice. With lattice trapping of & 10 3 atoms and a 265.6 nm probe laser linked to the LNE-SYRTE primary frequency reference we have determined the center frequency of the transition for a range of lattice wavelengths and at two lattice trap depths. We find the Stark-free (magic) wavelength to be 362.53(0.21) nm-essential knowledge for future use of this line in a clock with anticipated 10 À18 range accuracy. We also present evidence of the laser excitation of a Wannier-Stark ladder of states in a lattice of well depth 10E R .

PLOS One, 2009

Protein kinases are the most common protein domains implicated in cancer, where somatically acqui... more Protein kinases are the most common protein domains implicated in cancer, where somatically acquired mutations are known to be functionally linked to a variety of cancers. Resequencing studies of protein kinase coding regions have emphasized the importance of sequence and structure determinants of cancer-causing kinase mutations in understanding of the mutation-dependent activation process. We have developed an integrated bioinformatics resource,

Journal of visualized experiments : JoVE, 2011

Skeletal muscle contains multiple progenitor populations of distinct embryonic origins and develo... more Skeletal muscle contains multiple progenitor populations of distinct embryonic origins and developmental potential. Myogenic progenitors, usually residing in a "satellite cell position" between the myofiber plasma membrane and the laminin-rich basement membrane that ensheaths it, are self-renewing cells that are solely committed to the myogenic lineage. We have recently described a second class of vessel associated progenitors that can generate myofibroblasts and white adipocytes, which responds to damage by efficiently entering proliferation and provides trophic support to myogenic cells during tissue regeneration. One of the most trusted assays to determine the developmental and regenerative potential of a given cell population relies on their isolation and transplantation. To this end we have optimized protocols for their purification by flow cytometry from enzymatically dissociated muscle, which we will outline in this article. The populations obtained using this metho...

The open rheumatology journal, 2014

Systemic sclerosis (SSc) is a complex disease involving multiple genetic factors. A recent genome... more Systemic sclerosis (SSc) is a complex disease involving multiple genetic factors. A recent genome-wide association study (GWAS) indicated that CD247 was strongly associated with SSc, which was subsequently confirmed in a SSc cohort of European population. However, genetic heterogeneity in different ethnic populations may significantly impact the complex trait of SSc. The studies herein aimed to examine whether the SSc-associated SNP rs2056626 of CD247 identified in Caucasian is also associated with Han Chinese SSc. A Han Chinese cohort consisting of 387 SSc patients and 523 healthy controls were examined in the studies. TaqMan assays were performed to examine the SNP. Exact p-values were obtained (Fisher's test) from 2x2 tables of allele counts and disease status. The results showed that there was no association between rs2056626 of CD247 and SSc or any SSc subtypes of Han Chinese. The negative results are important in understanding genetics of SSc in different ethnic population...

2011 XXXth URSI General Assembly and Scientific Symposium, 2011

$Research paper thumbnail of Neutral Atom Frequency Reference in the Deep Ultraviolet with Fractional Uncertainty=5.7×10^{-15}$

Physical Review Letters, 2012

A neutral atom frequency reference in the deep UV with 10 −15 range uncertainty We present an ass... more A neutral atom frequency reference in the deep UV with 10 −15 range uncertainty We present an assessment of the (6s 2 ) 1 S0 ↔ (6s7s) 3 P0 clock transition frequency in 199 Hg with an uncertainty reduction of nearly three orders of magnitude and demonstrate an atomic quality factor, Q, of ∼10 14 . The 199 Hg atoms are confined in a vertical lattice trap with light at the newly determined magic wavelength of 362.5697±0.0011 nm and at a lattice depth of 20 ER. The atoms are loaded from a single stage magneto-optical trap with cooling light at 253.7 nm. The high Q factor is obtained with an 80 ms Rabi pulse at 265.6 nm. The frequency of the clock transition is found to be 1 128 575 290 808 162.0 ± 6.4 (sys.) ± 0.3 (stat.) Hz (fractional uncertainty = 5.7×10 −15 ). Neither an atom number nor second order Zeeman dependence have yet to be detected. Only three laser wavelengths are used for the cooling, lattice trapping, probing and detection.

Physical Review A, 2011

... Recent work includes (i) generating 253.7 nm light for four-wave mixing in mercury to produce... more ... Recent work includes (i) generating 253.7 nm light for four-wave mixing in mercury to produce continuous Lyman-α radiation for the awaited laser cooling of antihydrogen [24] and (ii) magneto-optic trapping of Hg for an anticipated ultraprecise frequency standard [25,26]. ...

Optics Letters, 2010

Laser cooling and trapping of neutral mercury is performed in a single-stage 1 S 0 ↔ 3 P 1 3D mag... more Laser cooling and trapping of neutral mercury is performed in a single-stage 1 S 0 ↔ 3 P 1 3D magneto-optical trap. We give a detailed account of the atom cloud size and temperature for both bosonic ( 200 Hg and 202 Hg) and fermionic ( 199 Hg and 201 Hg) isotopes. The bosonic isotope temperatures are in close agreement with Doppler cooling theory, while temperatures obtained for the fermionic isotopes are lower, suggesting the presence of sub-Doppler cooling. A minimum temperature of 29 AE 4 μK is achieved for 201 Hg.

Optics Express, 2009

A new source of two diode laser beams, spatially separated but optically phase-locked with each o... more A new source of two diode laser beams, spatially separated but optically phase-locked with each other, is used to study the modulation transfer spectroscopy of coherent population trapping resonance (CPT). The spectrum for the (87)Rb D2 line is obtained with narrow linewidth and high signal-to-noise ratio, and analyzed with different experimental parameters. A theoretical analysis of the CPT modulation transfer spectra is deduced from the density matrix equation of motion, and found to be in good agreement with the experimental results.

Nature Immunology, 2005

The molecular mechanisms that direct the migration of early T lymphocyte progenitors to the thymu... more The molecular mechanisms that direct the migration of early T lymphocyte progenitors to the thymus are unknown. We show here that P-selectin is expressed by thymic endothelium and that lymphoid progenitors in bone marrow and thymus bind P-selectin. Parabiosis, competitive thymus reconstitution and short-term homing assays indicated that P-selectin and its ligand PSGL-1 are functionally important components of the thymic homing process. Accordingly, thymi of mice lacking PSGL-1 contained fewer early thymic progenitors and had increased empty niches for prothymocytes compared with wild-type mice. Furthermore, the number of resident thymic progenitors controls thymic expression of P-selectin, suggesting that regulation of P-selectin expression by a thymic 'niche occupancy sensor' may be used to direct progenitor access.

Measurement, 2009

We propose and demonstrate a method to promote the robustness for the stabilized optical frequenc... more We propose and demonstrate a method to promote the robustness for the stabilized optical frequency comb (OFC) referenced on the microwave atomic clock. The phase-locked loop (PLL) for the repetition rate of the OFC uses the charge-pump phase-frequency detector (CPPFD) instead of a double-balanced mixer (DBM), which serves as the phase detector in the traditional OFC locking schemes. The phase noise performance of the CPPFD scheme is achieved to the same level as the traditional DBM scheme, while the capture range of the PLL is significantly broadened. This greatly enhances the robustness of the stabilized OFC without degrading the noise performance.