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Nan Yu

Publications and source records attributed to Nan Yu.

10 recordsLinked to original sources
PubMed2006

Multistage two-dimensional magneto-optical trap as a compact cold atom beam source.

A compact cold atom beam source based on a multistage two-dimensional magneto-optical trap (MOT) has been demonstrated and characterized. The multiple-stage design greatly reduces the overall size of the source apparatus while providing a high flux of atoms. The cold atom beam was used to load a separate MOT in ultrahigh vacuum, and we obtained an actual trap loading rate of 1.5 x 109 atoms/s while using only 20 mW of total laser power for the source. The entire source apparatus, including optics, can fit into a 4 cm x 4 cm x 13 cm volume.

Journal Article↗
PubMed2005

Ultralow-noise mode-locked laser with coupled optoelectronic oscillator configuration.

We describe simultaneous generation of ultralow-noise optical pulses and microwave signal with a mode-locked fiber laser in a coupled optoelectronic oscillator configuration. We demonstrate 9.2-GHz optical and microwave signals with the measured phase noise of -140 dBc/Hz at 10-kHz offset frequency. We show that the mode-locked laser in the photonic oscillator serves as a high-Q filter and is responsible for the observed low phase noise.

Journal Article↗
PubMed2004

Control of plant trichome development by a cotton fiber MYB gene.

Cotton (Gossypium spp) plants produce seed trichomes (cotton fibers) that are an important commodity worldwide; however, genes controlling cotton fiber development have not been characterized. In Arabidopsis thaliana the MYB gene GLABRA1 (GL1) is a central regulator of trichome development. Here, we show that promoter of a cotton fiber gene, RD22-like1 (RDL1), contains a homeodomain binding L1 box and a MYB binding motif that confer trichome-specific expression in Arabidopsis. A cotton MYB protein GaMYB2/Fiber Factor 1 transactivated the RDL1 promoter both in yeast and in planta. Real-time PCR and in situ analysis showed that GaMYB2 is predominantly expressed early in developing cotton fibers. After transferring into Arabidopsis, GL1::GaMYB2 rescued trichome formation of a gl1 mutant, and interestingly, 35S::GaMYB2 induced seed-trichome production. We further demonstrate that the first intron of both GL1 and GaMYB2 plays a role in patterning trichomes: it acts as an enhancer in trichome and a repressor in nontrichome cells, generating a trichome-specific pattern of MYB gene expression. Disruption of a MYB motif conserved in intron 1 of GL1, WEREWOLF, and GaMYB2 genes affected trichome production. These results suggest that cotton and Arabidopsis use similar transcription factors for regulating trichomes and that GaMYB2 may be a key regulator of cotton fiber development.

Amino Acid Motifs↗
PubMed2004

Observation of light dragging in a rubidium vapor cell.

We report on the experimental demonstration of the light dragging effect due to atomic motion in a rubidium vapor cell. We find that the minimum group velocity is achieved for light redshifted from the center of the atomic resonance and that the value of this shift increases with decreasing group velocity, in agreement with the theoretical predictions by Kocharovskaya, Rostovtsev, and Scully [Phys. Rev. Lett. 86, 628 (2001)].

Journal Article↗
PubMed2004

A method for cross-species gene expression analysis with high-density oligonucleotide arrays.

DNA microarrays have been widely used in gene expression analysis of biological processes. Due to a lack of sequence information, the applications have been largely restricted to humans and a few model organisms. Presented within this study are results of the cross-species hybridization with Affymetrix human high-density oligonucleotide arrays or GeneChip using distantly related mammalian species; cattle, pig and dog. Based on the unique feature of the Affymetrix GeneChip where every gene is represented by multiple probes, we hypothesized that sequence conservation within mammals is high enough to generate sufficient signals from some of the probes for expression analysis. We demonstrated that while overall hybridization signals are low for cross-species hybridization, a few probes of most genes still generated signals equivalent to the same-species hybridization. By masking the poorly hybridized probes electronically, the remaining probes provided reliable data for gene expression analysis. We developed an algorithm to select the reliable probes for analysis utilizing the match/mismatch feature of GeneChip. When comparing gene expression between two tissues using the selected probes, we found a linear correlation between the cross-species and same-species hybridization. In addition, we validated cross-species hybridization results by quantitative PCR using randomly selected genes. The method shown herein could be applied to both plant and animal research.

Algorithms↗
PubMed2004

[Expression of proteinase cathepsin L1 gene of Schistosoma japonicum in Escherichia coli].

OBJECTIVE: To express the proteinase cathepsin L1 gene of Schistosoma japonicum (SjCL1) in Escherichia coli JM109 cells. METHODS: The SjCL1 gene was amplified from the recombinant plasmid pcDNA3-SjCL1 by PCR. The gene was cloned into a prokaryotic expression vector pGEX4T-1 to construct a recombinant plasmid pGEX-SjCL1. The E. coli JM109 cells were transformed with the recombinant plasmid pGEX-SjCL1 and the transformants were induced by IPTG to express the recombinant protein, the target protein was then identified by SDS-PAGE and Western blotting. RESULTS: A 1 kb length PCR product was obtained and a recombinant plasmid pGEX-SjCL1 was constructed. The expression product was detected by SDS-PAGE and Western blotting and an expression band about 62000 was found. CONCLUSION: The SjCL1 gene is effectively expressed in the E. coli JM109 cells.

Animals↗
PubMed2004

Effects of lidocaine on cerebral oxygen supply-consumption balance and hemodynamics during anesthesia induction in patients with supratentorial tumor.

OBJECTIVE: To study the effects of lidocaine on the balance between cerebral oxygen supply-consumption and on the hemodynamics during anesthesia induction in patients with supratentorial tumor. METHODS: Twenty-four patients with supratentorial tumor were randomly divided into lidocaine group (n=12) and control group (n=12). Blood gas analysis and determinations of plasma lactic acid and glucose in the radial artery and internal jugular venous bulb were performed. Oxygen extraction ratio (OER) and blood oxygen content in the artery and internal jugular venous bulb were calculated during anesthesia induction. RESULTS: OER and difference declined in plasma lactic acid level between the internal jugular venous bulb and the artery, and blood oxygen saturation as well as blood oxygen pressure in the internal jugular venous bulb and the artery increased along with blood oxygen content in the internal jugular venous bulb in both groups during anesthesia induction. Comparison between the groups showed that only the changes in blood oxygen pressure in the internal jugular venous bulb were statistically significant. Changes in the hemodynamics in lidocaine group were less obvious than those in the control group during anesthesia induction. CONCLUSION: Lidocaine does not significantly influence cerebral oxygen balance and may effectively inhibit hemodynamic response during anesthesia induction in patients with supratentorial tumor.

Adult↗
PubMed2002

The comparative RNA web (CRW) site: an online database of comparative sequence and structure information for ribosomal, intron, and other RNAs.

BACKGROUND: Comparative analysis of RNA sequences is the basis for the detailed and accurate predictions of RNA structure and the determination of phylogenetic relationships for organisms that span the entire phylogenetic tree. Underlying these accomplishments are very large, well-organized, and processed collections of RNA sequences. This data, starting with the sequences organized into a database management system and aligned to reveal their higher-order structure, and patterns of conservation and variation for organisms that span the phylogenetic tree, has been collected and analyzed. This type of information can be fundamental for and have an influence on the study of phylogenetic relationships, RNA structure, and the melding of these two fields. RESULTS: We have prepared a large web site that disseminates our comparative sequence and structure models and data. The four major types of comparative information and systems available for the three ribosomal RNAs (5S, 16S, and 23S rRNA), transfer RNA (tRNA), and two of the catalytic intron RNAs (group I and group II) are: (1) Current Comparative Structure Models; (2) Nucleotide Frequency and Conservation Information; (3) Sequence and Structure Data; and (4) Data Access Systems. CONCLUSIONS: This online RNA sequence and structure information, the result of extensive analysis, interpretation, data collection, and computer program and web development, is accessible at our Comparative RNA Web (CRW) Site http://www.rna.icmb.utexas.edu. In the future, more data and information will be added to these existing categories, new categories will be developed, and additional RNAs will be studied and presented at the CRW Site.

Base Sequence↗
PubMed2002

[The expression of glucocorticold receptor isoform in peripheral blood mononuclear cell with Graves' ophthalmopathy].

OBJECTIVE: To study the expression of glucocorticoid receptor (GR) isoform in the peripheral blood mononuclear cell (PBMC) of patients with Graves' ophthalmopathy (GO). METHODS: Semi-quantitative RT-PCR was used to analyze RNA isolated from PBMC of the patients with GO and the normal volunteers. The level of plasma total cortisol (PTC) at 8 a.m. was measured. RESULTS: The hGR alpha/GR beta mRNA ratios of the two groups were 7.58 +/- 5.42 and 14.65 +/- 8.30, respectively. There was significant difference between the two groups (P < 0.05). The PTC levels of the two groups were 304.23 +/- 92.06 and 313.73 +/- 111.05, and no significant difference between them was noted (P > 0.05). No correlation was found between hGR alpha/GR beta mRNA and PTC levels. CONCLUSION: hGR alpha/GR beta mRNA may play a role in the pathogeny of Graves' ophthalmopathy.

Adult↗