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1.
Morey Timothy E. Varshney Manoj Flint Jason A. Seubert Christoph N. Smith W. Brit Bjoraker David G. Shah Dinesh O. Dennis Donn M. 《Journal of nanoparticle research》2004,6(2):159-170
Background: Although microemulsion-based nanoparticles (MEs) may be useful for drug delivery or scavenging, these benefits must be balanced against potential nanotoxicological effects in biological tissue (bio-nano interface). We investigated the actions of assembled MEs and their individual components at the bio-nano interface of thrombosis and hemolysis in human blood.
Methods: Oil-in-water MEs were synthesized using ethylbutyrate, sodium caprylate, and pluronic F-68 (ME4) or F-127 (ME6) in 0.9% NaClw/v. The effects of MEs or components on thrombosis were determined using thrombo-elastography, platelet contractile force, clot elastic modulus, and platelet counting. For hemolysis, ME or components were incubated with erythrocytes, centrifuged, and washed for measurement of free hemoglobin by spectroscopy.
Results and conclusions: The mean particle diameters (polydispersity index) for ME6 and ME4 were 23.6 ± 2.5 nm (0.362) and 14.0 ± 1.0 nm (0.008), respectively. MEs (0, 0.03, 0.3, 3 mM) markedly reduced the thromboelastograph maximal amplitude in a concentration-dependent manner (49.0 ± 4.2, 39.0 ± 5.6, 15.0 ± 8.7, 3.8 ± 1.3 mm, respectively), an effect highly correlated (r2 = 0.94) with similar changes caused by pluronic surfactants (48.7 ± 10.9, 30.7 ± 15.8, 20.0 ± 11.3, 2.0 ± 0.5) alone. Neither oil nor sodium caprylate alone affected the thromboelastograph. The clot contractile force was reduced by ME (27.3 ± 11.1–6.7 ± 3.4 kdynes/cm2, P = 0.02, n = 5) whereas the platelet population not affected (175 ± 28–182 ± 23 106/ml, P = 0.12, n = 6). This data suggests that MEs reduced platelet activity due to associated pluronic surfactants, but caused minimal changes in protein function necessary for coagulation. Although pharmacological concentrations of sodium caprylate caused hemolysis (EC50 = 213 mM), MEs and pluronic surfactants did not disrupt erythrocytes. Knowledge of nanoparticle activity and potential associated nanotoxicity at this bio-nano interface enables rational ME design for in vivo applications. 相似文献
2.
The concept of strong interactions need not be limited to the sector of physics taken by QCD. While this domain is investigated by RHIC, LHC will be able to probe potential new strong interactions simultaneously: Finding the precise mechanism for electroweak symmetry breaking is one of the prime problems of physics. Intricately linked to this point is the question after the true nature or even the existence of the Higgs boson. Here, we present stronly interacting theories providing an explanation for the hierarchy problem and leading to a light composite Higgs boson, favoured by experimental data. Our variation of the standard model is consistent with precision data. We achieve this accordance by using technifermions in a higher representation of their gauge group. Anomaly conditions require at least one extra lepton family for some of the theories whereby they contain a natural dark matter candidate. We can accurately determine the masses of said leptons from experimental data. 相似文献
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6.
Ashwani K. Padthe Nalin A. Chaturvedi Dennis S. Bernstein Sanjay P. Bhat Anthony M. Waas 《International Journal of Non》2008,43(4):277-291
We study a linearly damped preloaded two-bar linkage that exhibits hysteresis due to the presence of multiple attracting equilibria. The dynamics at the unstable equilibrium, through which a snap-through buckle occurs, are not linearizable due to a solution-dependent singularity. We stabilize the unstable equilibrium using two distinct non-linear controllers. The feedback-linearization controller requires knowledge of the linkage parameters, whereas the robust version of the intrinsic non-linear proportional-derivative controller requires only an upper bound on the stiffness. 相似文献
7.
Huseyin Zengin Gulay Zengin Dennis W. Smith 《Journal of polymer science. Part A, Polymer chemistry》2006,44(24):6988-6996
This study focuses on the preparation, characterization, and optical properties of new bis(3,4‐diphenylethynylphenyl)phenylamine. This is the first nitrogen‐containing bis‐ortho‐diynylarene (BODA) monomer having a nitrogen atom as the spacer group. BODA monomers are usually prepared from common bisphenols, thereby providing great synthetic versatility and the opportunity to develop a wide array of novel polyarylene thermosets by varying the aromatic spacer group. The new bis(3,4‐bisphenylethynylphenyl)phenylamine was synthesized in five steps. This compound emits an intense blue color (λ = 438 nm) upon irradiation by UV light and may be suitable for use as an emitting layer in electroluminescent devices. Bis‐(3,4‐bisphenylethynylphenyl)phenylamine and its polymer have photoluminescence quantum yields 34 and 38%, respectively, and long excited‐state lifetimes of 3.2 and 3.6 ns, respectively. The structure of the monomer and its polymer were characterized using spectroscopic techniques including Ultraviolet–visible Spectrophotometer, Photoluminescence Spectrophotometer, Fourier Transform infrared spectroscopy, and Gel Permeation Chromatography. The polymerizations were studied by Differential Scanning Calorimeter. The amount of weight loss and the thermostability of the nitrogen‐containing polymer were determined from thermogravimetric analysis. The electrical conductivity of neat HCl‐doped BODA‐derived polymer film was measured according to the standard four‐point probe technique. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6988–6996, 2006 相似文献
8.
Dennis Lo 《Optical and Quantum Electronics》1988,20(3):257-262
Through the use of a PFL (pulse-forming line) of conveniently changeable output impedance ZO, the electrical characteristics of a small volume-discharge of standard XeCl laser gas mix was studied. The impedance ZD from a 2×0.5×1(=1) cm3 discharge was found to be about 10. A PFL of very low impedance is therefore rather inefficient in driving the discharge, because of the impedance mismatch and the slower current rise time. The data presented will be useful for the design of excimer lasers of small discharge volume, which find applications in serving as master oscillator or in high repetition rate operation. 相似文献
9.
Summary We consider a walk from a stateA
1 to a stateA
n+1 in which the probability of remaining atA
i
isp
i
, and the probability of progressing fromA
i
toA
i+1 is 1 –p
i
. The probabilityW
nk
of reachingA
n+1 fromA
1 in exactlyn + k steps can then be expressed as a polynomial of degreen + k in then variablesp
1,,p
n
. We determine the maximum value ofW
nk
and the (unique) choice (p
1,,p
n
) for which this extremum occurs.Dedicated to Professor Otto Haupt with best wishes on his 100th birthday 相似文献
10.
Chen TF Yoder JD Hruby DE 《European journal of mass spectrometry (Chichester, England)》2004,10(4):501-508
Myristoylpeptides were synthesized in order to determine if a neutral loss of 210 Da, C14H26O (the mass of the myristoyl moiety), was universal and observable by both liquid chromatography electrospray ionization quadrupole ion trap (LC-ESI-QIT) and matrix-assisted laser desorption/ionization time-of-flight time-of-flight (MALDI-ToF/ToF) mass spectrometry. Myristoylation was successfully introduced on the N-terminus, internally on the amino group of lysine and arginine. Larger peptides and the arginine compounds needed elevated temperatures for myristoylation. To our knowledge, this is the first report of a chemically-synthesized myristoylated arginine in a peptide. Collision energy studies for the LC-ESI-QIT instrument showed that modified peptides and a loss of 210 Da could be detected under commonly used conditions (energy level between 30 and 42%) with picomole amounts of sample. The loss of myristoyl moiety is observed on the MALDI-Tof/Tof mass spectrometer as well. Due to the hydrophobic properties of the myristoyl moiety, it is not surprising that the modified peptides all formed at least dimers, and in some cases trimers. We were also able to distinguish a mixture of two mono-myristoylated peptides. MS3 data from the LC-ESI-QIT instrument on a di-myristoylated peptide indicates the loss of 210 Da at either the N-terminus or lysine. We were also able to analyze a mixture of modified and unmodified peptides on the MALDI-ToF/ToF instrument. The data presented in this paper demonstrates the constant neutral loss of the 210 Da, C14H26O, from both N-terminally and internally myristoylated peptides can be identified unambiguously using LC-ESI-QIT or MALDI-ToF/ToF mass spectrometers. This will be a useful tool in determining the myristoylation status of candidate proteins after enzyme digestion, and in elucidating the modification sites of internal myristoyl proteins. 相似文献