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901.
Pallabi Pal Quynh C. Nguyen Angela H. Benton Mary E. Marquart Amol V. Janorkar 《Macromolecular bioscience》2019,19(9)
Emphasizing the role of hydrogel stiffness and cellular differentiation, this study develops collagen and elastin‐like polypeptide (ELP)–based bone regenerative hydrogels loaded with recombinant human bone morphogenetic protein‐2 (rhBMP‐2) and doxycycline with mechanical properties suitable for osteogenesis. The drug‐incorporated collagen–ELP hydrogels has significantly higher modulus of 35 ± 5 kPa compared to collagen‐only hydrogels. Doxycycline shows a bi‐phasic release with an initial burst release followed by a gradual release, while rhBMP‐2 exhibits a nearly linear release profile for all hydrogels. The released doxycycline shows anti‐microbial activity against Pseudomonas aeruginosa, Streptococcus sanguinis, and Escherichia coli. Microscopic observation of the hydrogels reveals their interconnected, macroporous, 3D open architecture with pore diameters between 160 and 400 µm. This architecture supports human adipose–derived stem cell attachment and proliferation from initial days of cell seeding, forming a thick cellular sheath by day 21. Interestingly, in collagen and collagen–ELP hydrogels, cell morphology is elongated with stretched slender lamellipodial formation, while cells assemble as spheroidal aggregates in crosslinked as well as drug‐loaded hydrogels. Osteogenic markers, alkaline phosphatase and osteocalcin, are expressed maximally for drug‐loaded hydrogels compared to those without drugs. The drug‐loaded collagen–ELP hydrogels are thus promising for combating bacterial infection and promoting guided bone regeneration. 相似文献
902.
We constructed a novel tunable comb-filter by splicing a commercial Yb3+ doped fiber (YDF) between 2 thermally expanded core (TEC) fibers at their core-expanded ends. This structure forms an all-fiber Mach-Zehnder interferometer due to the interference between the core mode and the cladding modes of the YDF. The interference fringes shifts to the longer wavelength region as the YDF is pumped by a 980 nm laser diode (LD). We then demonstrated application of this newly proposed tunable comb-filter to a SOA-based ring laser and obtained multi-wavelength lasing. The lasing wavelengths can be also tuned by pumping the YDF in the proposed comb-filter. 相似文献
903.
Abouzaid E Arenton M Barker AR Bellantoni L Bellavance A Blucher E Bock GJ Cheu E Coleman R Corcoran MD Cox B Erwin AR Escobar CO Glazov A Golossanov A Gomes RA Gouffon P Hsiung YB Jensen DA Kessler R Kotera K Ledovskoy A McBride PL Monnier E Nguyen H Niclasen R Ii DG Ping H Ramberg EJ Ray RE Ronquest M Santos E Slater W Smith D Solomey N Swallow EC Toale PA Tschirhart R Wah YW Wang J White HB Whitmore J Wilking MJ Winstein B Winston R Wolfe C Worcester ET Worcester M Yamanaka T Zimmerman ED 《Physical review letters》2008,100(13):131803
The Fermilab KTeV experiment has searched for lepton-flavor-violating decays of the K(L) meson in three decay modes. We observe no events in the signal region for any of the modes studied, and we set the following upper limits for their branching ratios at the 90% C.L.: BR(K(L) --> pi(0) micro(+/-) e(-/+)) <7.6 x 10(-11); BR(K(L) --> pi(0)pi(0) micro(+/-) e(-/+)) <1.7 x 10(-10); BR(pi(0) --> micro(+/-) e(-/+)) <3.6 x 10(-10). This result represents a factor of 82 improvement in the branching ratio limit for K(L) --> pi(0) micro(+/-) e(-/+) and is the first reported limit for K(L) --> pi(0)pi(0) micro(+/-) e(-/+). 相似文献
904.
Schülzgen A Li L Nguyen D Spiegelberg Ch Rogojan RM Laronche A Albert J Peyghambarian N 《Optics letters》2008,33(6):614-616
A distributed feedback fiber laser made of highly Er-Yb codoped phosphate glass fiber has been demonstrated experimentally. Efficient pump absorption allows for multimode pumping into the cladding of the active fiber. Output powers up to 160 mW have been achieved. The 35 mm long fiber laser device emits with >50 dB side mode suppression ratio. 相似文献
905.
The problem of RNA genomes packaged inside spherical viruses is studied. The RNA-capsid attraction is assumed to be nonspecific and occurs at the inner capsid surface only. For weak attraction, RNA concentration is maximum at the center of the capsid to maximize their configurational entropy. For stronger attraction, RNA concentration peaks near the capsid surface. In the latter case, the competition between the branching of RNA secondary structure and its adsorption to the inner capsid results in the formation of a dense layer of RNA near capsid surface. The layer thickness is a slowly varying (logarithmic) function of the capsid inner radius. Consequently, the amount of RNA packaged is proportional to the capsid area (or the number of proteins) instead of its volume. The numerical profiles describe reasonably well the observed RNA concentration profiles of various viruses. 相似文献
906.
Quantum transport in disordered ferromagnetic (III,Mn)V semiconductors is studied theoretically. Mesoscopic wires exhibit an Anderson disorder-induced metal-insulator transition that can be controlled by a weak external magnetic field. This metal-insulator transition should also occur in other materials with large anisotropic magnetoresistance effects. The transition can be useful for studies of zero-temperature quantum critical phase transitions and fundamental material properties. 相似文献
907.
Nguyen Ba An 《Physics letters. A》2008,372(21):3778-3783
In this work we devise a scheme to teleport a type of unknown M-quNit state using only a single non-maximally entangled quNit-pair as the quantum channel. The fidelity is one while the success probability is less than one and depends on N but not on M. The scheme requires M−1 ancillary quNits and 1 qubit at the receiver's and the receiver should be capable of performing some quNit-quNit/qubit operations. The classical message that the teleporter must announce consists only of 2 Nits, though the full set of his/her measurement outcome is as huge as M+1 Nits. 相似文献
908.
Sara J. Palmer Ray L. Frost Godwin Ayoko Tai Nguyen 《Journal of Raman spectroscopy : JRS》2008,39(3):395-401
Raman spectroscopy has been used to characterise synthetic mixed carbonate and molybdate hydrotalcites of formula Mg6Al2(OH)16((CO3)2−,(MoO4)2−)·4H2O. The spectra have been used to assess the molecular assembly of the cations and anions in the hydrotalcite structure. The spectra may be conveniently subdivided into spectral features on the basis of the carbonate anion, the molybdate anion, the hydroxyl units and water units. Bands are assigned to the hydroxyl stretching vibrations of water. Three types of carbonate anions are identified: (1) carbonate hydrogen‐bonded to water in the interlayer, (2) carbonate hydrogen‐bonded to the hydrotalcite hydroxyl surface, (3) free carbonate anions. It is proposed that the water is highly structured in the hydrotalcite, as it is hydrogen bonded to both the carbonate and the hydroxyl surface. The spectra have been used to assess the contamination of carbonate in an open reaction vessel in the synthesis of a molybdate hydrotalcite of formula Mg6Al2(OH)16((CO3)2−, (MoO4)2−)·4H2O. Bands are assigned to carbonate and molybdate anions in the Raman spectra. Importantly, the synthesis of hydrotalcites from solutions containing molybdate provides a mechanism for the removal of this oxy‐anion. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
909.
Razvigor Ossikovski Quang Nguyen Gennaro Picardi Joachim Schreiber Pierre Morin 《Journal of Raman spectroscopy : JRS》2008,39(5):661-672
We present the theory underlying the large numerical aperture objective micro‐Raman backscattering experiment and apply it to the elaboration of a characterization methodology for the determination of the stress tensor in strained cubic semiconductor structures. The presented stress characterization technique consists in monitoring the variations of the stress‐sensitive optical phonon peak position and linewidth while rotating stepwise the sample about its normal. The practical application of the technique is illustrated on a silicon‐on‐insulator (SOI) microelectronic structure demonstrating a plane stress‐tensor determination. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
910.
Nikolai A. Poklonski Nguyen Ngoc Hieu Sergey A. Vyrko Andrei M. Popov 《Physics letters. A》2008,372(35):5706-5711
The dependence of the interwall conductance on distance between walls and relative positions of walls are calculated at the low voltage by Bardeen method for (n,n)@(2n,2n) double-walled carbon nanotubes (DWCNTs) with n=5,6,…,10. The calculations show that interwall conductance does not depend on temperature (for T?500 K) and current-voltage characteristic is linear. The conductance decreases by 6 orders of magnitude when the interwall distance is doubled. Thus, depending on the interwall distance, DWCNTs can be used as temperature stable nanoresistors or nanocapacitors. 相似文献