2,173 research outputs found
Efficient Quantum Computation using Coherent States
Universal quantum computation using optical coherent states is studied. A
teleportation scheme for a coherent-state qubit is developed and applied to
gate operations. This scheme is shown to be robust to detection inefficiency.Comment: 6 pages, 5 figures, extended and modified (in print, PRA
Particle Pair Production in Cosmological General Relativity
The Cosmological General Relativity (CGR) of Carmeli, a 5-dimensional (5-D)
theory of time, space and velocity, predicts the existence of an acceleration
a_0 = c / tau due to the expansion of the universe, where c is the speed of
light in vacuum, tau = 1 / h is the Hubble-Carmeli time constant, where h is
the Hubble constant at zero distance and no gravity.
The Carmeli force on a particle of mass m is F_c = m a_0, a fifth force in
nature.
In CGR, the effective mass density rho_eff = rho - rho_c, where rho is the
matter density and rho_c is the critical mass density which we identify with
the vacuum mass density rho_vac = -rho_c.
The fields resulting from the weak field solution of the Einstein field
equations in 5-D CGR and the Carmeli force are used to hypothesize the
production of a pair of particles.
The mass of each particle is found to be m = tau c^3 / 4 G, where G is
Newton's constant.
The vacuum mass density derived from the physics is rho_vac = -rho_c = -3 /
(8 pi G tau^2).
The cosmic microwave background (CMB) black body radiation at the temperature
T_o = 2.72548 K which fills that volume is found to have a relationship to the
ionization energy of the Hydrogen atom. Define the radiation energy
epsilon_gamma = (1 - g) m c^2 / N_gamma, where (1-g) is the fraction of the
initial energy m c^2 which converts to photons, g is a function of the baryon
density parameter Omega_b and N_gamma is the total number of photons in the CMB
radiation field. We make the connection with the ionization energy of the first
quantum level of the Hydrogen atom by the hypothesis epsilon_gamma = [(1 - g) m
c^2] / N_gamma = alpha^2 mu c^2 / 2, where alpha is the fine-structure constant
and mu = m_p f / (1 + f), where f= m_e / m_p with m_e the electron mass and m_p
the proton mass.Comment: 14 pages, 0 figures. The final publication is available at
springerlink.co
Experimental poisoning by Baccharis megapotamica var. weirii in buffalo
Five male 6-8 month-old Murrah buffalo calves were orally dosed with the fresh aerial parts of Baccharis megapotamica var. weirii at doses of 1, 3, 4, 5 and 10g/kg body weight (bw) (~1-10mg macrocyclic trichothecenes/kg/bw). The B. megapotamica used for the experiment was harvested on a farm where a recent spontaneous outbreak of poisoning caused by such plant had occurred. Clinical signs appeared 4-20 hours and 4 buffaloes died 18-49 hours after the ingestion of the plant. Clinical signs were apathy, anorexia, and watery diarrhea, fever, colic, drooling, muscle tremors, restlessness, laborious breathing and ruminal atony, and dehydration. The most consistent gross findings were restricted to the gastrointestinal (GI) tract consisted of varying degrees of edema and reddening of the mucosa of the forestomach. Histopathological findings consisted of varying degrees of necrosis of the epithelial lining of the forestomach and of lymphocytes within lymphoid organs and aggregates. Fibrin thrombi were consistently found in sub-mucosal vessels of the forestomach and in the lumen of hepatic sinusoids. It is suggested that dehydration, septicemia and disseminated intravascular coagulation participate in the pathogenesis of the intoxication and play a role as a cause of death. A subsample of B. megapotamica var. weirii was frozen-dried and ground and analyzed using UHPLC (Ultra High Performance Liquid Chromatography) with high resolution Time of Flight mass spectrometry and tandem mass spectrometry, it was shown that the plant material contained at least 51 different macrocyclic trichothecenes at a total level of 1.1-1.2mg/g. About 15-20% of the total trichothecenes contents was found to be monosaccharide conjugates, with two thirds of these being glucose conjugates and one third constituted by six aldopentose conjugates (probably xylose), which has never been reported in the literature
Insulin therapy modulates mitochondrial dynamics and biogenesis, autophagy and tau protein phosphorylation in the brain of type 1 diabetic rats
AbstractThe main purpose of this study was to examine whether streptozotocin (STZ)-induced type 1 diabetes (T1D) and insulin (INS) treatment affect mitochondrial function, fission/fusion and biogenesis, autophagy and tau protein phosphorylation in cerebral cortex from diabetic rats treated or not with INS. No significant alterations were observed in mitochondrial function as well as pyruvate levels, despite the significant increase in glucose levels observed in INS-treated diabetic rats. A significant increase in DRP1 protein phosphorylated at Ser616 residue was observed in the brain cortex of STZ rats. Also an increase in NRF2 protein levels and in the number of copies of mtDNA were observed in STZ diabetic rats, these alterations being normalized by INS. A slight decrease in LC3-II levels was observed in INS-treated rats when compared to STZ diabetic animals. An increase in tau protein phosphorylation at Ser396 residue was observed in STZ diabetic rats while INS treatment partially reversed that effect. Accordingly, a modest reduction in the activation of GSK3β and a significant increase in the activity of phosphatase 2A were found in INS-treated rats when compared to STZ diabetic animals. No significant alterations were observed in caspases 9 and 3 activity and synaptophysin and PSD95 levels. Altogether our results show that mitochondrial alterations induced by T1D seem to involve compensation mechanisms since no significant changes in mitochondrial function and synaptic integrity were observed in diabetic animals. In addition, INS treatment is able to normalize the alterations induced by T1D supporting the importance of INS signaling in the brain
The Giant Anisotropic Magnetocaloric Effect In Dyal2
We report on calculations of the anisotropic magnetocaloric effect in DyAl2 using a model Hamiltonian including crystalline electrical field effects. The anisotropic effect is produced by the rotation of a constant magnetic field from the easy to a hard magnetic direction in the crystal and is enhanced by the first order nature of the field induced spin reorientation transition. The calculated results indicate that for a field with modulus of 2 T rotating from a hard to the easy direction, the isothermal magnetic entropy (Δ Siso) and adiabatic temperature (Δ Tad) changes present peak values higher than 60% the ones observed in the usual process, in which the field direction is kept constant and the modulus of the field is varied. © 2008 American Institute of Physics.1049Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , 1st ed. (Institute of Physics, Bristol)Warburg, E., (1881) Ann. Phys. (N.Y.), 13, p. 141. , 0003-4916Brown, G.V., (1976) J. Appl. Phys., 47, p. 3673. , 0021-8979 10.1063/1.323176Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 0031-9007 10.1103/PhysRevLett.78.4494Von Ranke, P.J., De Oliveira, N.A., Mello, C., Garcia, D.C., De Souza, V.A., Magnus, A., Carvalho, G., (2006) Phys. Rev. B, 74, p. 054425. , 0163-1829 10.1103/PhysRevB.74.054425Hill, T.W., Wallace, W.E., Craig, R.S., Inuone, T.J., (1973) Solid State Chem., 8, p. 364. , 10.1016/S0022-4596(73)80036-2De Oliveira, I.G., Garcia, D.C., Von Ranke, P.J., (2007) J. Appl. Phys., 102, p. 073907. , 0021-8979 10.1063/1.2783781Lima, A.L., Tsokol, A.O., Gschneidner Jr., K.A., Pecharky, V.K., Lograsso, T.A., Schlagel, D.L., (2005) Phys. Rev. B, 72, p. 024403. , 0163-1829 10.1103/PhysRevB.72.024403Von Ranke, P.J., De Oliveira, I.G., Guimarães, A.P., Da Silva, X.A., (2000) Phys. Rev. B, 61, p. 447. , 0163-1829 10.1103/PhysRevB.61.447Von Ranke, P.J., De Oliveira, N.A., Garcia, D.C., De Sousa, V.S.R., De Souza, V.A., Magnus, A., Carvalho, G., Reis, M.S., (2007) Phys. Rev. B, 75, p. 184420. , 0163-1829 10.1103/PhysRevB.75.184420Purwins, H.G., Leson, A., (1990) Adv. Phys., 39, p. 309. , 0001-8732 10.1080/00018739000101511Von Ranke, P.J., Pecharsky, V.K., Gschneidner Jr., K.A., (1998) Phys. Rev. B, 58, p. 1211
A novel method to quantify IRDye800CW fluorescent antibody probes ex vivo in tissue distribution studies
BACKGROUND: We describe a new method for biodistribution studies with IRDye800CW fluorescent antibody probes. This method allows the quantification of the IRDye800CW fluorescent tracer in percentage of injected dose per gram of tissue (% ID/g), and it is herein compared to the generally used reference method that makes use of radioactivity. METHODS: Cetuximab was conjugated to both the near-infrared fluorophore IRDye800CW and/or the positron emitter 89-zirconium, which was injected in nude mice bearing A431 human tumor xenografts. Positron emission tomography (PET) and optical imaging were performed 24 h post-injection (p.i.). For the biodistribution study, organs and tumors were collected 24 h p.i., and each of these was halved. One half was used for the determination of probe uptake by radioactivity measurement. The other half was homogenized, and the content of the fluorescent probe was determined by extrapolation from a calibration curve made with the injected probe. RESULTS: Tumors were clearly visualized with both modalities, and the calculated tumor-to-normal tissue ratios were very similar for optical and PET imaging: 3.31 ± 1.09 and 3.15 ± 0.99, respectively. Although some variations were observed in ex vivo analyses, tumor uptake was within the same range for IRDye800CW and gamma ray quantification: 15.07 ± 3.66% ID/g and 13.92 ± 2.59% ID/g, respectively. CONCLUSIONS: The novel method for quantification of the optical tracer IRDye800CW gives similar results as the reference method of gamma ray quantification. This new method is considered very useful in the context of the preclinical development of IRDye800CW fluorescent probes for optical molecular imaging, likely contributing to the selection of lead compounds that are the most promising for clinical translation
Optimizing the fast Rydberg quantum gate
The fast phase gate scheme, in which the qubits are atoms confined in sites
of an optical lattice, and gate operations are mediated by excitation of
Rydberg states, was proposed by Jaksch et al. Phys. Rev. Lett. 85, 2208 (2000).
A potential source of decoherence in this system derives from motional heating,
which occurs if the ground and Rydberg states of the atom move in different
optical lattice potentials. We propose to minimize this effect by choosing the
lattice photon frequency \omega so that the ground and Rydberg states have the
same frequency-dependent polarizability \alpha(omega). The results are
presented for the case of Rb.Comment: 5 pages, submitted to PR
Transnational cooperation in enhancing researchers’ wider employability: the TRANSPEER project
The purpose of this paper is to provide an example of best practice towards enhancing employability in the cross-sectoral labour market for doctorate-holders. This was achieved through an Erasmus+ KA2 (Strategic Partnership) skills development project which created a training programme (TRANSPEER) involving a multi-disciplinary cohort of researchers at a range of career stages, drawn from universities in Norway, Portugal, Sweden and the UK.info:eu-repo/semantics/publishedVersio
Volatile and glycosidically bound composition of Loureiro and Alvarinho wines
Composition of Loureiro and Alvarinho wines from the Vinhos Verdes region,
respecting free volatile compounds as well as glycosidically bound aroma precursors,
was exhaustively determined by GC-MS after adsorption on XAD-2 resin. On the
whole, were identified and quantified 120 volatile compounds in the free fraction and
77 glycosidically bound compounds, belonging to C6-compounds, alcohols, fatty acids
ethyl esters, esters of organic acids, acetates, monoterpenic alcohols, monoterpenic
oxides and diols, C13-norisoprenoids, volatile phenols, volatile fatty acids and carbonyl
compounds. Globally, the wines of the two cultivars present similar composition on
volatiles. However, respecting varietal compounds, Loureiro wines are richer than
Alvarinho ones with regard to C6-compounds and monoterpenic compounds, occurring
the opposite for volatile phenols. It was also demonstrate that wines of both varieties
may benefit the aroma reserve, present as glycoconjugates, as it is susceptible of
being technologically explored. Linalool, Ho-trienol, α-terpineol, contributing with
fruity and floral notes, and β-damascenone mostly for Alvarinho, confering tropical
fruit notes, are the varietal compounds which may particularly influence the aroma of
these wines. Respecting fermentative compounds, Alvarinho is also particularly rich in
fatty acids ethyl esters related to lipid metabolism and acetates of fusel alcohols,
which can provide it a fruity character; Loureiro contains higher levels of esters of
organic acids and 2-phenylethanol, conferring fruity and floral notes. Sensory analysis
agree with chemical analyses showing a pronounced tree and tropical fruit character
for Alvarinho wines while Loureiro wines present more intense citrus fruit notes.Centre of Biological
Engineering of Universidade do Minho; Estação VitivinĂcola Amândio
Galhano (EVAG); Solar de Serrade; EVAG; ComissĂŁo de Viticultura da RegiĂŁo dos Vinhos Verdes
Synthesis, surface active and antimicrobial properties of new alkyl 2,6-dideoxy-L-arabino-hexopyranosides
Synthesis of alkyl 2,6-dideoxy-L-arabino-hexopyranosides was accomplished by the reaction of 1,5-anhydro-2,6-dideoxy-L-arabino-hex-1-enitol with fatty alcohols in dichloromethane, catalyzed by triphenylphosphine hydrobromide. Reaction with octanol and dodecanol gave the corresponding α-glycosides in 50% and 42% yield, the β-glycosides in 20% and 21% yield and the α-anomer of the Ferrier product in 10% and 9% yield, respectively.Deacetylation of the α-/β-glycosides with sodium methoxide in methanol afforded the amphiphilic L-arabino-hexopyranosides in 94–99% yield. The surface tension at the air–water interface of the octyl L-glycosides and of the dodecyl α-L-glycoside aqueous solutions at 35 °C was measured with a du Noüy ring tensiometer and surface properties such as critical micelle concentration (CMC), relative surface excess, molecular area at the interface and Gibbs micellization free energy were evaluated. The stereochemistry of the hexopyranoside ring in unimers and aggregates is correlated to the hydrophobicity and packing efficiency on the air–water interface. The antibacterial and antifungal activities of the surface-active glycosides were evaluated using the paper disk diffusion method. The dodecyl α-L-arabino-hexopyranoside was quite active over Bacillus cereus and Bacillus subtilis, while low activity was found for this glycoside over Enterococcus faecalis and Listeria monocytogenes. The octyl glycosides tested showed low activity over almost all the above-mentioned bacteria, and also over the fungus Candida albicans. No inhibition of Salmonella enteritidis and of the filamentous fungus Aspergillus niger was detected for any of the compounds tested.info:eu-repo/semantics/publishedVersio
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