| 1. |
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| 2. |
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| 3. |
- Martz, Dale, et al.
(författare)
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Large area high efficiency broad bandwidth 800 nm dielectric gratings for high energy laser pulse compression
- 2009
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 17:26, s. 23809-23816
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Tidskriftsartikel (refereegranskat)abstract
- We have demonstrated broad bandwidth large area (229 mm x 114 mm) multilayer dielectric diffraction gratings for the efficient compression of high energy 800 nm laser pulses at high average power. The gratings are etched in the top layers of an aperiodic (Nb0.5Ta0.5)2O5-SiO2 multilayer coating deposited by ion beam sputtering. The mean efficiency of the grating across the area is better than 97% at the center wavelength and remains above 96% at wavelengths between 820 nm and 780 nm. The gratings were used to compress 5.5 J pulses from a Ti:sapphire laser with an efficiency above 80 percent.
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| 4. |
- Rocca, J. J., et al.
(författare)
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Compact Soft X-ray Lasers for Imaging, Material Processing, and Characterization at the Nanoscale
- 2007
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Ingår i: 32nd IEEE/CPMT International Electronic Manufacturing Technology Symposium. - 9781424413355 ; , s. 72-73
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Konferensbidrag (refereegranskat)abstract
- As manufacturing of devices advances into the nanoscale, critical feature sizes have rapidly shrunk to below the wavelength of visible light. These advances in nanotechnology have created a need to develop better ways of accessing the nanoworld. The extreme ultraviolet (EUV)/ soft x-ray (SXR) region of the spectrum provides an opportunity to use coherent light at wavelengths that are 10- to 100-times shorter than visible light, at 1 to 100 nm. Given the diffraction limit in imaging resolution, these wavelengths allow us to "see" smaller features and "write" smaller patterns than would be possible with visible light. We have developed compact laser-pumped and discharge-pumped lasers operating at wavelengths of λ=13.2 nm [1] and λ=46.9 nm [2] respectively, and have used them in the demonstration of nanoscale full field imaging [3,4], nanopatterning [5], and nanoscale laser ablation [6]. The high brightness and short wavelength output from these lasers when combined with specialized EUV/SXR optics, offer unique opportunities for the implementation of table-top imaging, patterning and metrology tools with superior spatial resolution for applications in nanoscience and nanotechnology. Using these new compact short wavelength lasers we have built two microscopes, using λ=46.9 nm or λ=l 3.2 nm laser illumination. The compact λ=46.9 nm microscope (Fig. 1a and lb) condenses the light using a multilayer coated Schwarzschild mirror, and images the test object using a diffractive zone plate lens. The spatial resolution of this microscopes was assessed by imaging test samples consisting of dense line gratings of half-periods ranging from 200 down to 35 nm. Figure 2(a) and (b) show images of a 100 nm and 70 nm half-period gratings obtained with the λ =46.9 nm microscope. The lineout in the image of the 70 nm lines shows a modulation of ∼30% indicating that the features are fully resolved according to the Rayleigh criterion. By rearranging the optics, the λ=46.9 nm microscope can also image surfaces. An image of fully resolved dense metal lines, with half-period of 170 nm, patterned on the silicon wafer is shown in Figure 2 (c). The shorter wavelength λ= 3.2 nm microscope uses all zone plate optics to render images of transmissive test patterns with increased spatial resolution . An image of fully resolved 50 nm half-period dense lines acquired with a 20 seconds exposure is shown in Figure 2(d). From images like this one, the spatial resolution of the λ=13.2 nm table-top microscope was determined to be better than 38 nm [3]. The high coherence of these short wavelength lasers also allows for the printing of arrays of nanoscale features using interferometric lithography. We have demonstrated combined a λ=46.9 nm capillary discharge laser and a Lloyd's mirror to print arrays of cone-shaped nano-dots with ∼ 58 nm FWHM diameter (Fig 3a) [5]. The same arrangement was used to print arrays of nano-holes 120 nm FWHM and 100 nm in depth over areas in excess of 500 × 500 μm2 in different photoresists using exposure times as short as 80 s. Larger area patterns can be readily printed using precision translation stages and multiple exposures by overlay superposition. The ability to focus SXL laser light into near diffraction-limited spots also opens the possibility to develop new types of nanoprobes. We have demonstrated ablation of sub-100 nm diameter holes by directly focusing the output of a λ=46.9 nm laser onto a sample with a zone plate lens. Figure 3(b) shows an AFM image of a 82 nm diameter crater obtained ablating a 500 nm thick PMMA layer with a single laser shot. The holes were observed to have very clean walls and high reproducibility. We have recently added the capability to spectroscopically analyze the light emitted from the plasma created during the ablation, opening the possibility to develop analytic nanoprobles. All of these results illustrate the capabilities of compact short wavelength lasers for nanotechnology applications.
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| 5. |
- Rocca, J. J., et al.
(författare)
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High brightness table-top soft x-ray lasers at high repetition rate : injection-seeding of solid target plasma amplifiers and other developments - art. no. 670202
- 2007
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Ingår i: SOFT X-RAY LASERS AND APPLICATIONS VII. - : SPIE. ; , s. 70202-70202
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Konferensbidrag (refereegranskat)abstract
- We have recently demonstrated high repetition rate tabletop lasers operating at wavelengths as short as 10.9 rim based on collisional transient excitation of ions in plasmas created by laser heating of solid targets. As a further step in the development of these lasers into very high brightness and fully coherent soft x-ray sources, we have demonstrated injection seeding of the amplifiers with high harmonic seed pulses. We report results of an experiment in which a 32.6 rim Ne-like Ti amplifier was used to amplify a seed pulse from the 25(th) harmonic of Ti:Sapphire into the gain saturation regime. Simultaneous amplification of the 27(th) harmonic at 30.1 nm was also observed. The seeded soft x-ray laser beam was measured to approach full spatial coherence. We have demonstrated that this scheme is scalable to shorter wavelengths and that is capable of producing extremely bright soft x-ray laser pulse with essentially full coherence.
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| 6. |
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| 7. |
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Visioning and Engineering the Knowledge Society - A Web Science Perspective : Second World Summit on the Knowledge Society, WSKS 2009, Chania, Crete, Greece, September 2009. Proceedings
- 2009
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Proceedings (redaktörskap) (refereegranskat)abstract
- This book, in conjunction with the volume CCIS 49, constitutes the refereed proceedings of the Second World Summit, WSKS 2009, held in Chania, Crete, Greece, in September 2008.The 62 revised full papers presented were carefully reviewed and selected from 256 submissions. The papers are deal with information technologies - knowledge management systems - e-business and business, organizational and inter-organizational information systems for the Knowledge Society, knowledge, learning, education, learning technologies and e-learning for the Knowledge Society, social and humanistic computing for the Knowledge Society – emerging technologies for the society and the humanity, culture and cultural heritage - technology for culture management - management of tourism and entertainment - tourism networks in the Knowledge Society, e-government and e-democracy in the Knowledge Society, innovation, sustainable development and strategic management for the Knowledge Society, service science, management, engineering, and technology, intellectual and human capital development in the Knowledge Society, advanced applications for environmental protection and green economy management, future prospects for the Knowledge Society: from foresight studies to projects and public policies, technologies and business models for the creative industries.
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| 8. |
- Brizuela, F., et al.
(författare)
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High resolution full-field imaging of nanostructures using compact extreme ultraviolet lasers
- 2009
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Ingår i: 9TH INTERNATIONAL CONFERENCE ON X-RAY MICROSCOPY. - : IOP Publishing.
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Konferensbidrag (refereegranskat)abstract
- Recent advances in the development of high peak brightness table-top extreme ultraviolet (EUV) and soft x-ray (SRX) lasers have opened new opportunities for the demonstration of compact full-field EUV/SXR microscopes capable of capturing images with short exposures down to a single laser shot. We demonstrate the practical application of table-top zone plate EUV microscopes that can image nanostructures with a spatial resolution of 54 nm and below and exposure times as short as 1.2 ns, the duration of a single laser shot.
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| 9. |
- Brizuela, F., et al.
(författare)
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Near-wavelength Resolution Extreme Ultraviolet Imaging With a Desktop-size Laser
- 2008
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Ingår i: 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9. ; , s. 400-401
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Konferensbidrag (refereegranskat)abstract
- We have realized the first demonstration of imaging in the extreme ultraviolet (EUV) with near-wavelength spatial resolution, 54 nm, using a uniquely compact full-field microscope that can produce images with a single one nanosecond exposure.
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| 10. |
- Davies, Melvyn B, et al.
(författare)
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The MODEST questions: Challenges and future directions in stellar cluster research
- 2006
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Ingår i: New Astronomy. - : Elsevier BV. - 1384-1092 .- 1384-1076. ; 12:3, s. 201-214
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Forskningsöversikt (refereegranskat)abstract
- We present a review of some of the current major challenges in stellar cluster research, including young clusters, globular clusters, and galactic nuclei. Topics considered include: primordial mass segregation and runaway mergers, expulsion of gas from clusters, the production of stellar exotica seen in some clusters (e.g., blue stragglers and extreme horizontal-branch stars), binary populations within clusters, the black-hole population within stellar clusters, the final parsec problem, stellar dynamics around a massive black hole, and stellar collisions. The Modest Questions posed here are the outcome of discussions which took place at the Modest-6A workshop held in Lund, Sweden, in December, 2005. Modest-6A was organised as part of the activities of the Modest Collaboration (see www.manybody.org for further details).
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| 11. |
- Hicks, J, et al.
(författare)
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Novel patterns of genome rearrangement and their association with survival in breast cancer
- 2006
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Ingår i: Genome research. - : Cold Spring Harbor Laboratory. - 1088-9051. ; 16:12, s. 1465-1479
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Tidskriftsartikel (refereegranskat)abstract
- Representational Oligonucleotide Microarray Analysis (ROMA) detects genomic amplifications and deletions with boundaries defined at a resolution of ∼50 kb. We have used this technique to examine 243 breast tumors from two separate studies for which detailed clinical data were available. The very high resolution of this technology has enabled us to identify three characteristic patterns of genomic copy number variation in diploid tumors and to measure correlations with patient survival. One of these patterns is characterized by multiple closely spaced amplicons, or “firestorms,” limited to single chromosome arms. These multiple amplifications are highly correlated with aggressive disease and poor survival even when the rest of the genome is relatively quiet. Analysis of a selected subset of clinical material suggests that a simple genomic calculation, based on the number and proximity of genomic alterations, correlates with life-table estimates of the probability of overall survival in patients with primary breast cancer. Based on this sample, we generate the working hypothesis that copy number profiling might provide information useful in making clinical decisions, especially regarding the use or not of systemic therapies (hormonal therapy, chemotherapy), in the management of operable primary breast cancer with ostensibly good prognosis, for example, small, node-negative, hormone-receptor-positive diploid cases.
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| 12. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
- 2008
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Ingår i: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
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Forskningsöversikt (refereegranskat)abstract
- Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
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| 13. |
- Kolz, Melanie, et al.
(författare)
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Meta-analysis of 28,141 individuals identifies common variants within five new loci that influence uric acid concentrations
- 2009
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Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 5:6, s. e1000504-
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Tidskriftsartikel (refereegranskat)abstract
- Elevated serum uric acid levels cause gout and are a risk factor for cardiovascular disease and diabetes. To investigate the polygenetic basis of serum uric acid levels, we conducted a meta-analysis of genome-wide association scans from 14 studies totalling 28,141 participants of European descent, resulting in identification of 954 SNPs distributed across nine loci that exceeded the threshold of genome-wide significance, five of which are novel. Overall, the common variants associated with serum uric acid levels fall in the following nine regions: SLC2A9 (p = 5.2×10−201), ABCG2 (p = 3.1×10−26), SLC17A1 (p = 3.0×10−14), SLC22A11 (p = 6.7×10−14), SLC22A12 (p = 2.0×10−9), SLC16A9 (p = 1.1×10−8), GCKR (p = 1.4×10−9), LRRC16A (p = 8.5×10−9), and near PDZK1 (p = 2.7×10−9). Identified variants were analyzed for gender differences. We found that the minor allele for rs734553 in SLC2A9 has greater influence in lowering uric acid levels in women and the minor allele of rs2231142 in ABCG2 elevates uric acid levels more strongly in men compared to women. To further characterize the identified variants, we analyzed their association with a panel of metabolites. rs12356193 within SLC16A9 was associated with DL-carnitine (p = 4.0×10−26) and propionyl-L-carnitine (p = 5.0×10−8) concentrations, which in turn were associated with serum UA levels (p = 1.4×10−57 and p = 8.1×10−54, respectively), forming a triangle between SNP, metabolites, and UA levels. Taken together, these associations highlight additional pathways that are important in the regulation of serum uric acid levels and point toward novel potential targets for pharmacological intervention to prevent or treat hyperuricemia. In addition, these findings strongly support the hypothesis that transport proteins are key in regulating serum uric acid levels.
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| 14. |
- Menoni, C. S., et al.
(författare)
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Advances in Nanoscale Resolution Soft X-Ray Laser Microscopy
- 2009
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Ingår i: X-RAY LASERS 2008, PROCEEDINGS. - : Springer Netherlands. - 9781402099236 ; , s. 341-347
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Konferensbidrag (refereegranskat)abstract
- We review our most recent results on table-top, nanometer-scale resolution, microscopy using compact soft x-ray lasers developed at Colorado State University. We have realized the first demonstration of wavelength-resolution microscopy in the soft x-ray spectral range. Images of carbon nanotubes, 50 nm in diameter, were obtained with a single similar to 1 ns duration laser pulse from a desk-top size capinary discharge 46.9 nm laser. We fully characterized the new microscope by measuring the modulation transfer function of the instrument for zone plate objectives with three different numerical apertures, demonstrating that 54 nm half-period structures can be resolved. The combination of near-wavelength spatial resolution with high temporal resolution imaging opens myriad opportunities for imaging nanoscale structures.
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| 15. |
- Menoni, C. S., et al.
(författare)
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Nanometer-scale imaging and ablation with Extreme Ultraviolet lasers
- 2007
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Ingår i: 2007 CONFERENCE ON LASERS & ELECTRO-OPTICS/QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2007), VOLS 1-5. - 9781424435906 ; , s. 1401-1402
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Konferensbidrag (refereegranskat)abstract
- The short wavelength and high brightness of compact extreme ultraviolet lasers is shown to enable the development of microscopes with spatial resolution of tens of nanometers and new types of nanoprobes.
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| 16. |
- Menoni, C. S., et al.
(författare)
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Nanoscale resolution microscopy and ablation with extreme ultraviolet lasers
- 2007
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Ingår i: 2007 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2. - 9781424409242 ; , s. 488-489
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Konferensbidrag (refereegranskat)abstract
- We obtain a spatial resolution down to 38 run with full field imaging and laser-ablation systems that exploit the short wavelength and high brightness output from compact extreme ultraviolet lasers in combination with zone plate optics.
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| 17. |
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| 18. |
- Misulovin, Ziva, et al.
(författare)
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Association of cohesin and Nipped-B with transcriptionally active regions of the Drosophila melanogaster genome
- 2008
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Ingår i: Chromosoma. - : Springer Science and Business Media LLC. - 0009-5915 .- 1432-0886. ; 117:1, s. 89-102
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Tidskriftsartikel (refereegranskat)abstract
- The cohesin complex is a chromosomal component required for sister chromatid cohesion that is conserved from yeast to man. The similarly conserved Nipped-B protein is needed for cohesin to bind to chromosomes. In higher organisms, Nipped-B and cohesin regulate gene expression and development by unknown mechanisms. Using chromatin immunoprecipitation, we find that Nipped-B and cohesin bind to the same sites throughout the entire non-repetitive Drosophila genome. They preferentially bind transcribed regions and overlap with RNA polymerase II. This contrasts sharply with yeast, where cohesin binds almost exclusively between genes. Differences in cohesin and Nipped-B binding between Drosophila cell lines often correlate with differences in gene expression. For example, cohesin and Nipped-B bind the Abd-B homeobox gene in cells in which it is transcribed, but not in cells in which it is silenced. They bind to the Abd-B transcription unit and downstream regulatory region and thus could regulate both transcriptional elongation and activation. We posit that transcription facilitates cohesin binding, perhaps by unfolding chromatin, and that Nipped-B then regulates gene expression by controlling cohesin dynamics. These mechanisms are likely involved in the etiology of Cornelia de Lange syndrome, in which mutation of one copy of the NIPBL gene encoding the human Nipped-B ortholog causes diverse structural and mental birth defects.
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| 19. |
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| 21. |
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| 22. |
- Wachulak, P., et al.
(författare)
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Interferometric lithography with an amplitude division interferometer and a desktop extreme ultraviolet laser
- 2008
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Ingår i: Journal of the Optical Society of America. B, Optical physics. - : Optical Society of America. - 0740-3224 .- 1520-8540. ; 25:7, s. B104-B107
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a compact interferometric lithography nanopatterning tool based on an amplitude division interferometer (ADI) and a 46.9 nm wavelength desktop size capillary discharge laser. The system is designed to print arrays of lines, holes, and dots with sizes below 100 nm on high resolution photoresists for the fabrication of arrays of nanostructures with physical and biological applications. The future combination of this ADI with high repetition rate tabletop lasers operating at shorter wavelengths should allow the printing of arrays of sub-10 nm size features with a tabletop setup.
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