136,951 research outputs found
A single E-box in the <i>Cel-lin-3</i> CRM is not sufficient for <i>lin-3</i> expression in the anchor cell of <i>C</i>. <i>elegans</i>.
No full text(A) New cis-regulatory lin-3 alleles with deleted E-boxL and NHR or NHR and E-boxR. (B) Quantification of vulval induction in these new mutants. Note the complete absence of any induction in the recovered lin-3 alleles (n>30). Scorings of lin-3(1417) animals are the same as those reported in Fig 5 and are used here to indicate that this mutation leads to vulval hypo-induction rather than no induction at all. (C-D) smFISH in lin-3(mf72) (C) and N2 (D) animals. Green spots correspond to lin-3 transcripts and red spots to lag-2 that is used as an anchor cell marker. Blue is DAPI staining of nuclei. Note the absence of lin-3 expression in the anchor cell in the lin-3(mf72) mutant animal. Absence of lin-3 signal in the anchor cell was also confirmed for the other lin-3 alleles.</p
Spatially coherent high-order harmonics generated at optimal high gas pressure with high-intensity one- or two-color laser pulses
Full text linkCitation: Jin, C., & Lin, C. D. (2016). Spatially coherent high-order harmonics generated at optimal high gas pressure with high-intensity one- or two-color laser pulses. Physical Review A, 94(4), 6. doi:10.1103/PhysRevA.94.043804We investigate the gas-pressure dependence of macroscopic harmonic spectra generated in a high-ionization medium using intense 800-nm laser pulses. The harmonics obtained at the optimal pressure show good spatial coherence with small divergence (less than 2 mrad) in the far field. By analyzing the evolution of the laser's electric field as it propagates, we find that dynamic phase matching conditions are fulfilled in the second half of the gas cell and that harmonic yields do not depend on the position of the gas cell with respect to the focusing position. We also demonstrate that harmonic yields at the optimal pressure can be further enhanced by increasing input laser energy or by adding a few percent of second or third harmonic to the fundamental
Analysis of THz generation through the asymmetry of photoelectron angular distributions
Full text linkCitation: Zhou, Z. Y., Wang, X., & Lin, C. D. (2017). Analysis of THz generation through the asymmetry of photoelectron angular distributions. Physical Review A, 95(3), 6. doi:10.1103/PhysRevA.95.033418We analyze the mechanism of THz generation in a gas medium with intense two-color infrared lasers pulses. The dependence of the amplitude of THz emission on the relative phase between the fundamental color (800 nm) and its second harmonic (400 nm) is shown to be identical to the residual current as well as to the asymmetry of the above-threshold-ionization (ATI) photoelectrons along the left versus the right side of the linear polarization axis of the laser, thus confirming the validity of the semiclassical photocurrent model for the THz emission. We further analyze the even vs odd angular momentum distributions of the ATI electrons. The degree of overlap between the even-parity dominant electrons and the odd-parity dominant electrons within each ATI peak determines the strength of the THz emission, thus favoring the model that THz is generated through free-free transitions in the laser field. A model is also provided to obtain the same phase dependence as the four-wave mixing model
Identification of cis-regulatory elements from the C. elegans Hox gene lin-39 required for embryonic expression and for regulation by the transcription factors LIN-1, LIN-31 and LIN-39
No full textExpression of the Caenorhabditis elegans Hox gene lin-39 begins in the embryo and continues in multiple larval cells, including the P cell lineages that generate ventral cord neurons (VCNs) and vulval precursor cells (VPCs). lin-39 is regulated by several factors and by Wnt and Ras signaling pathways; however, no cis-acting sites mediating lin-39 regulation have been identified. Here, we describe three elements controlling lin-39 expression: a 338-bp upstream fragment that directs embryonic expression in P5-P8 and their descendants in the larva, a 247-bp intronic region sufficient for VCN expression, and a 1.3-kb upstream cis-regulatory module that drives expression in the VPC P6.p in a Ras-dependent manner. Three trans-acting factors regulate expression via the 1.3-kb element. A single binding site for the ETS factor LIN-1 mediates repression in VPCs other than P6.p; however, loss of LIN-1 decreases expression in P6.p. Therefore, LIN-1 acts both negatively and positively on lin-39 in different VPCs. The Forkhead domain protein LIN-31 also acts positively on lin-39 in P6.p via this module. Finally, LIN-39 itself binds to this element, suggesting that LIN-39 autoregulates its expression in P6.p. Therefore, we have begun to unravel the cis-acting sites regulating lin-39 Hox gene expression and have shown that lin-39 is a direct target of the Ras pathway acting via LIN-1 and LIN-31..SC: 0S; 7B; 0T; CA; PE; EC; SO; AA; XURL: URL; E-MAIL; DOI; DIGITAL-OBJECT-IDENTIFIERSource type: Electronic(1)[email protected]; http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WDG-4K0C9JV-3&_user=10&_coverDate=09%2F15%2F2006&_rdoc=21&_fmt=summary&_orig=browse&_srch=doc-info(%23toc%236766%232006%23997029997%23633147%23FLA%23display%23Volume)&_cdi=6766&_sort=d&_docanchor=&view=c&_ct=24&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=3e6063983fd5b459eac74b274375875e; http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=doi%3a10.1016%2fj.ydbio.2006.05.008&issn=0012-1606&isbn=&volume=297&issue=2&spage=550&pages=550-565&date=2006&title=Developmental%20Biology&atitle=Identification%20of%20cis-regulatory%20elements%20from%20the%20C.%20elegans%20Hox%20gene%20lin-39%20required%20for%20embryonic%20expression%20and%20for%20regulation%20by%20the%20transcription%20factors%20LIN-1%2c%20LIN-31%20and%20LIN-39.&aulast=Wagmaister&pid=%3Cauthor%3EWagmaister%2c%20J%20A%3bMiley%2c%20G%20R%3bMorris%2c%20C%20A%3bGleason%2c%20J%20E%3bMiller%2c%20L%20M%3bKornfeld%2c%20K%3bEisenmann%2c%20D%20M%3C%2Fauthor%3E%3CAN%3E20073040429%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
D* (D)over-bar* molecule interpretation of Z(c)(4025)
No full textWe have used QCD sum rules to study the newly observed charged state Z(c)(4025) as a hidden-charm D*(D) over bar* molecular state with the quantum numbers I-G(J(P)) =1(+)(1(+)). Using a D*(D) over bar* molecular interpolating current, we have calculated the two-point correlation function and the spectral density up to dimension eight at leading order in alpha(s). The extracted mass is m(X) = (4.04 +/- 0.24) GeV. This result is compatible with the observed mass of Z(c)(4025) within the errors, which implies a possible molecule interpretation of this new resonance. We also predict the mass of the corresponding hidden-bottom B*(B) over bar* molecular state: m(Zb) = (9.98 +/- 0.21) GeV.Physics, Particles & FieldsSCI(E)[email protected]; [email protected]; [email protected]; [email protected]
LIN-1 sumoylation is required for ventral toroid contraction.
No full text(A) Wild-type and K10A, K169A mutant LIN-1::GFP expression in L3 larvae at the Pn.px stage after VPC-specific degradation of AID::SMO-1 from the L2 stage onward. The 1° and 2° VPC descendants are underlined in white. The left panels show the corresponding DIC images overlaid with the LIN-1::GFP signal in green. (B) Quantification of LIN-1::GFP expression levels in 1° and 2° VPC descendants at the Pn.px stage in LIN-1::GFP wild-type and K10A, K169A double mutants under the indicated conditions. See S3 Fig for the corresponding measurements at the Pn.pxx stage. (C) Toroid morphogenesis defects in LIN-1 K10A and K169A single and double mutants at the L4 stage. Left panels show lateral views of z-projections. vulA and vulB1 toroids are outlined by the white rectangle in the top left panel and shown in top (xz) views in the right panels. (D) Quantification of vulA contraction, calculated as the ratio of the vulA and vulB1 toroid diameter. The box plots show the median values with the 25th and 75th percentiles and the whiskers indicate the maximum and minimum values. Where indicated, untreated controls are labelled with–IAA (blue) and animals treated with 1 mM auxin with +IAA (red). In each graph, the numbers of animals scored are indicated by the numbers in brackets. Statistical significance in (B) and (D) was calculated with unpaired two-tailed t-tests. p-values are indicated as * p ≤ 0.05; ** p ≤ 0.01; *** p ≤ 0.001. The scale bars are 10 μm.</p
Optimal generation of spatially coherent soft X-ray isolated attosecond pulses in a gas-filled waveguide using two-color synthesized laser pulses
Full text linkCitation: Jin, C., Hong, K. H., & Lin, C. D. (2016). Optimal generation of spatially coherent soft X-ray isolated attosecond pulses in a gas-filled waveguide using two-color synthesized laser pulses. Scientific Reports, 6, 11. doi:10.1038/srep38165We numerically demonstrate the generation of intense, low-divergence soft X-ray isolated attosecond pulses in a gas-filled hollow waveguide using synthesized few-cycle two-color laser waveforms. The waveform is a superposition of a fundamental and its second harmonic optimized such that highest harmonic yields are emitted from each atom. We then optimize the gas pressure and the length and radius of the waveguide such that bright coherent high-order harmonics with angular divergence smaller than 1 mrad are generated, for photon energy from the extreme ultraviolet to soft X-rays. By selecting a proper spectral range enhanced isolated attosecond pulses are generated. We study how dynamic phase matching caused by the interplay among waveguide mode, neutral atomic dispersion, and plasma effect is achieved at the optimal macroscopic conditions, by performing time-frequency analysis and by analyzing the evolution of the driving laser's electric field during the propagation. Our results, when combined with the on-going push of high-repetition-rate lasers (sub- to few MHz's) may eventually lead to the generation of high-flux, low-divergence soft X-ray tabletop isolated attosecond pulses for applications
Phase-retrieval algorithm for the characterization of broadband single attosecond pulses
Full text linkCitation: Zhao, X., Wei, H., Wu, Y., & Lin, C. D. (2017). Phase-retrieval algorithm for the characterization of broadband single attosecond pulses. Physical Review A, 95(4), 8. doi:10.1103/PhysRevA.95.043407Recent progress in high-order harmonic generation with few-cycle mid-infrared wavelength lasers has pushed light pulses into the water-window region and beyond. These pulses have the bandwidth to support single attosecond pulses down to a few tens of attoseconds. However, the present available techniques for attosecond pulse measurement are not applicable to such pulses. Here we report a phase-retrieval method using the standard photoelectron streaking technique where an attosecond pulse is converted into its electron replica through photoionization of atoms in the presence of a time-delayed infrared laser. The iterative algorithm allows accurate reconstruction of the spectral phase of light pulses, from the extreme-ultraviolet (XUV) to soft x-rays, with pulse durations from hundreds down to a few tens of attoseconds. At the same time, the streaking laser fields, including short pulses that span a few octaves, can also be accurately retrieved. Such well-characterized single attosecond pulses in the XUV to the soft-x-ray region are required for time-resolved probing of inner-shell electronic dynamics of matter at their own timescale of a few tens of attoseconds
LIN-2/CASK binds to both ACR-16 and UNC-29 through SH3 domain.
No full text(A) Summary of interactions by Yeast two-hybrid. Strong interaction (++); weak interaction (+), and no interactions (-) were indicated. (B) LIN-2A’s SH3 domain binds the ACR-16’s second intracellular loop (LoopII) in a Yeast two-hybrid assay. Y2HGold cells carrying indicated plasmids (Left) growing on selective media (-Trp/-Leu/-His/-Ade) is shown (Right). (C) LIN-2A’s SH3 domain binds the UNC-29’s second intracellular loop (LoopII) in the Yeast two-hybrid assay. (D-E) FRM-3 do not bind the ACR-16’s second intracellular loop (LoopII) (D) and UNC-29’s second intracellular loop (LoopII) (E) in the Yeast two-hybrid assay. (F-G) LIN-2A binds FRM-3 (F) and its FERM domain (G) requiring its PDZ domain, but not SH3 domain.</p
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