| 1. |
- Akkineni, Susrut, et al.
(author)
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Amyloid-like amelogenin nanoribbons template mineralization via a low-energy interface of ion binding sites
- 2022
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 119:19
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Journal article (peer-reviewed)abstract
- Protein scaffolds direct the organization of amorphous precursors that transform into mineralized tissues, but the templating mechanism remains elusive. Motivated by models for the biomineralization of tooth enamel, wherein amyloid-like amelogenin nanoribbons guide the mineralization of apatite filaments, we investigated the impact of nanoribbon structure, sequence, and chemistry on amorphous calcium phosphate (ACP) nucleation. Using full-length human amelogenin and peptide analogs with an amyloid-like domain, films of β-sheet nanoribbons were self-assembled on graphite and characterized by in situ atomic force microscopy and molecular dynamics simulations. All sequences substantially reduce nucleation barriers for ACP by creating low-energy interfaces, while phosphoserines along the length of the nanoribbons dramatically enhance kinetic factors associated with ion binding. Furthermore, the distribution of negatively charged residues along the nanoribbons presents a potential match to the Ca–Ca distances of the multi-ion complexes that constitute ACP. These findings show that amyloid-like amelogenin nanoribbons provide potent scaffolds for ACP mineralization by presenting energetically and stereochemically favorable templates of calcium phosphate ion binding and suggest enhanced surface wetting toward calcium phosphates in general.
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| 2. |
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| 3. |
- Reid, E, et al.
(author)
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A partial RH4 phenotype
- 2008
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In: Vox Sanguinis. - : Wiley. - 1423-0410 .- 0042-9007. ; 95:s1, s. 70-70
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Conference paper (peer-reviewed)
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| 4. |
- Singer, L. P., et al.
(author)
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The Needle in the 100 deg2 Haystack : Uncovering Afterglows of Fermi GRBs with the Palomar Transient Factory
- 2015
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In: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 806:1
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Journal article (peer-reviewed)abstract
- The Fermi Gamma-Ray Space Telescope has greatly expanded the number and energy window of observations of gamma-ray bursts (GRBs). However, the coarse localizations of tens to a hundred square degrees provided by the Fermi Gamma-ray Burst Monitor (GBM) instrument have posed a formidable obstacle to locating the bursts' host galaxies, measuring their redshifts, and tracking their panchromatic afterglows. We have built a target of opportunity mode for the intermediate Palomar Transient Factory (iPTF) in order to perform targeted searches for Fermi afterglows. Here, we present the results of one year of this program: eight afterglow discoveries, two of which (GRBs 130702A and 140606B) were at low redshift (z=0.145 and 0.384 respectively) and had spectroscopically confirmed broad-line type Ic supernovae. We present our broadband follow-up including spectroscopy as well as X-ray, UV, optical, millimeter, and radio observations. We study possible selection effects in the context of the total Fermi and Swift GRB samples. We identify one new outlier on the Amati relation. We find that two bursts are consistent with a mildly relativistic shock breaking out from the progenitor star, rather than the ultra-relativistic internal shock mechanism that powers standard cosmological bursts. Finally, in the context of the Zwicky Transient Facility (ZTF), we discuss how we will continue to expand this effort to find optical counterparts of binary neutron star mergers that may soon be detected by Advanced LIGO and Virgo.
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| 5. |
- Singh, A. A., et al.
(author)
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Green composites : Versatile material for future
- 2017
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In: Green Biocomposites. - Cham : Springer Verlag. ; , s. 29-44
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Book chapter (peer-reviewed)abstract
- The growing concern towards environmental problems and the urgent need for more versatile environmental friendly materials has led to increasing attention about polymer composites, i.e. fillers/reinforcing materials coming from renewable sources and biodegradable, especially from forest. The composites usually referred to as “green”, can find several industrial applications as discussed in this chapter. Biodegradable polymers coming from natural resources are also one important constituent of green composites. This chapter provides tactic for readers regarding the materials used for the fabrication and specific application of green composites in various fields. Furthermore, a discussion of the major material attributes of green composites is provided. From these focuses, a series of balancing application properties are explained. The chapter concludes that green composites have potential for use in a number of applications, but as with all design, one must carefully match the material to the application.
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| 6. |
- Baruah, S., et al.
(author)
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pH-dependent growth of zinc oxide nanorods
- 2009
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In: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 311:8, s. 2549-2554
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Journal article (peer-reviewed)abstract
- Here we study the effect of pH variation on the dimension and morphology of zinc oxide (ZnO) nanorods grown through hydrothermal process at temperatures less than 100 °C. ZnO nanorods were grown on pre-seeded glass substrates using zinc nitrate hexahydrate as the source of Zn ions and hexamethylenetetramine as the source of hydroxyl ions. The pH of the reaction bath was found to change gradually from 6.4 to 7.3 in 5 h during the growth process. The growth of the ZnO nanorods was observed to be faster, both laterally and longitudinally, when the growth solution was in basic conditions. However, flower petal like ZnO nanostructures were obtained when the growth process was initiated in basic condition (pH 8–12), indicating that initial acidic conditions were required to obtain nanorods with well-defined hexagonal facets. ZnO is known to erode in acidic condition and the final dimension of the nanorods is determined by a competition between crystal growth and etching. ZnO nanorods of different dimensions, both laterally (diameters ranging from 220 nm to 1 μm) and longitudinally (lengths ranging from 1 to 5.6 μm) were successfully synthesized using the same concentration of zinc nitrate and hexamine in the reaction bath and the same growth duration of 5 h simply through appropriate control of the pH of the reactant solution between 6 and 7.3.
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| 7. |
- Singerl, Peter, et al.
(author)
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A 2.7-GHz multi-level PWM carrier-bursting RF transmitter
- 2015
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In: European Microwave Week 2015: "Freedom Through Microwaves", EuMW 2015 - Conference Proceedings; 2015 45th European Microwave Conference Proceedings, EuMC. - 9782874870392 ; , s. 1124-1127
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Conference paper (peer-reviewed)abstract
- Carrier-bursting is an attractive RF transmitter concept to achieve high efficiency. The power amplifier (PA) itself either operates at its peak efficiency or is turned off. Another efficiency-enhancing approach is the Doherty concept, where the main PA reaches its peak efficiency already in back-off and the peak PA contributes at high input levels to reach the desired output power. In this work, we attempt to combine the best of both concepts and derive a two-level dual-output pulse width modulator driving two PAs whose outputs are combined. We have evaluated the concept by a real-Time FPGA implementation of the modulator for a 2.7GHz carrier driving two Class-AB PAs with a combined peak output power of 30W. The approach exhibits a potentially more pronounced back-off efficiency peak compared to the Doherty concept. Furthermore, the overall efficiency scales with the drain efficiency of the PAs and can thus be improved by employing Class-D or Class-F PAs.
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| 8. |
- Baruah, Sunandan, et al.
(author)
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Perspectives and applications of nanotechnology in water treatment
- 2016
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In: Environmental Chemistry Letters. - : Springer. - 1610-3653 .- 1610-3661. ; 14:1, s. 1-14
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Research review (peer-reviewed)abstract
- Industrialization and excessive use of pesticides for boosting agricultural production have adversely affected the ecosystem, polluting natural water reserves. Remediation of contaminated water has been an area of concern with numerous techniques being applied to improve the quality of naturally available water to the level suitable for human consumption. Most of these methods, however, generate by-products that are sometimes toxic. Heterogenous photocatalysis using metal oxide nanostructures for water purification is an attractive option because no harmful by-products are created. A discussion on possible methods to engineer metal oxides for visible light photocatalysis is included to highlight the use of solar energy for water purification. Multifunctional photocatalytic membranes are considered advantageous over freely suspended nanoparticles due to the ease of its removal from the purified water. An overview of water remediation techniques is presented, highlighting innovations through nanotechnology for possible addressing of problems associated with current techniques.
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| 9. |
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| 10. |
- Aghanim, N., et al.
(author)
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Planck 2018 results VIII. Gravitational lensing
- 2020
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 641
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Journal article (peer-reviewed)abstract
- We present measurements of the cosmic microwave background (CMB) lensing potential using the final Planck 2018 temperature and polarization data. Using polarization maps filtered to account for the noise anisotropy, we increase the significance of the detection of lensing in the polarization maps from 5 sigma to 9 sigma. Combined with temperature, lensing is detected at 40 sigma. We present an extensive set of tests of the robustness of the lensing-potential power spectrum, and construct a minimum-variance estimator likelihood over lensing multipoles 8 <= L <= 400 (extending the range to lower L compared to 2015), which we use to constrain cosmological parameters. We find good consistency between lensing constraints and the results from the Planck CMB power spectra within the Lambda CDM model. Combined with baryon density and other weak priors, the lensing analysis alone constrains (8)Omega (0.25)(m) = 0.589 +/- 0.020 sigma 8 Omega m 0.25 = 0.589 +/- 0.020 (1 sigma errors). Also combining with baryon acoustic oscillation data, we find tight individual parameter constraints, sigma (8)=0.811 +/- 0.019, H-0 = 67.9(-1.3)(+1.2) km s(-1) Mpc(-1) H 0 = 67 . 9 - 1.3 + 1.2 .> km s - 1 . Mpc - 1 , and Omega (m) = 0.303(-0.018)(+0.016) Omega m = 0 . 303 - 0.018 + 0.016 . Combining with Planck CMB power spectrum data, we measure sigma (8) to better than 1% precision, finding sigma (8)=0.811 +/- 0.006. CMB lensing reconstruction data are complementary to galaxy lensing data at lower redshift, having a different degeneracy direction in sigma (8)-Omega (m) space; we find consistency with the lensing results from the Dark Energy Survey, and give combined lensing-only parameter constraints that are tighter than joint results using galaxy clustering. Using the Planck cosmic infrared background (CIB) maps as an additional tracer of high-redshift matter, we make a combined Planck-only estimate of the lensing potential over 60% of the sky with considerably more small-scale signal. We additionally demonstrate delensing of the Planck power spectra using the joint and individual lensing potential estimates, detecting a maximum removal of 40% of the lensing-induced power in all spectra. The improvement in the sharpening of the acoustic peaks by including both CIB and the quadratic lensing reconstruction is detected at high significance.
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