Properties Of Spread Research Articles

Dynamic Monitoring of Oncolytic Adenovirus In Vivo by Genetic Capsid Labeling

Conditionally replicative adenoviruses represent a promising strategy to address the limited efficacy and safety issues associated with conventional cancer treatment. Despite rapid translation into human clinical trials and demonstrated safety, the fundamental properties of oncolytic adenovirus replication and spread and host-vector interactions in vivo have not been completely evaluated. We developed a noninvasive dynamic monitoring system to detect adenovirus replication. We constructed capsid-labeled E1/E3-deleted and wild-type adenoviruses (Ad-wt) by fusing the minor capsid protein IX with red fluorescent proteins mRFP1 and tdimer2(12), resulting in Ad-IX-mRFP1, Ad-IX-tdimer2(12), and Ad-wt-IX-mRFP1. Virus DNA replication, encapsidation, cytopathic effect, thermostability, and binding to primary receptor (coxsackie adenovirus receptor) were analyzed using real-time quantitative polymerase chain reaction, cell viability (MTS) assay, and fluorescence microscopy. Athymic mice (n = 4) carrying xenograft tumors that were derived from A549 lung adenocarcinoma cells were intratumorally inoculated with Ad-wt-IX-mRFP1, and adenovirus replication was dynamically monitored with a fluorescence noninvasive imaging system. Correlations between fluorescence signal intensity and viral DNA synthesis and replication were calculated using Pearson's correlation coefficient (r). The red fluorescence label had little effect on viral DNA replication, encapsidation, cytopathic effect, thermostability, and coxsackie adenovirus receptor binding. The fluorescent signal correlated with viral DNA synthesis and infectious progeny production both in vitro and in vivo (in A549 cells, r = .99 and r = .65; in tumors, r = .93 and r = .92, respectively). The replication efficiency of Ad-wt-IX-mRFP1 in vivo was variable, and replication and viral spreading and persistence were limited, consistent with clinical observations. Genetic capsid labeling provides a promising approach for the dynamic assessment of oncolytic adenovirus function in vivo.

Pricing Equity Default Swaps Using Structural Credit Models

In early 2004, new equity-credit hybrid derivatives that offered a larger spread than vanilla credit default swaps were developed. At the centre of this development was the equity default swap (EDS), which is the subject of this paper. Structural credit models allow the simultaneous modelling of a firm's credit quality and equity value, making them a natural framework to price equity-credit hybrid derivatives. A closed-form expression for the spread of an equity default swap, which incorporates the legal risk of the derivative, is derived in terms of parameters of a general structural model. A specific structural model, that developed by Leland & Toft, is calibrated by equity data and then used to investigate properties of the EDS spread. It is seen that an equity default swap with a low trigger price can have a substantially greater annual spread than a credit default swap. Also, it is shown that unless the dividend yield is very high, the EDS spread increases as a firm's debt-equity ratio increases, assuming that the firm's asset volatility is constant. However, if there are two reference firms with different debt-equity ratios but the same equity volatility, it is shown that there is a complex relationship between EDS spreads.

Statistical properties of the delay spread in a two path mobile radio with Nakagami fading channel

In this paper we study the statistical properties of the rms delay spread in a two path mobile radio environment, where each path is subject to Nakagami fading. We assume a typical urban power delay profile (exponential decay) for each path. Closed form equations for the mean of the rms delay spread are derived for different values of the m parameter of the Nakagami distribution. Monte Carlo simulations are also generated and compared with the analytical results.

Milk and soy protein films at the air–water interface

In this contribution we present a systematic comparison of the two major fractions of globulin from a soy protein isolate (β-conglycinin and glycinin, including the chemical reduction of glycinin with dithiothreitol (DTT)) and typical milk proteins (β-casein, caseinate, and WPI). The comparison is centred on the most important functional properties of spread and adsorbed protein films at the air–water interface (such as adsorption, structural, topographical, and dynamic characteristics), as a function of the aqueous phase pH and the protein concentration in the bulk phase and at interface. A combination of surface techniques (tensiometry, surface film balance, Brewster angle microscopy and surface dilatational rheology) was used in this study. A notable feature of soy proteins is the strong pH dependence of the molecular conformation and the associated functional properties, such as surface activity, film structure, surface dilatational viscoelasticity, and especially, the rate of adsorption at a fluid interface. Optimum functionality occurs at pH<5, which limits the application of soy globulins as food ingredients. In this respect the behaviour of milk and soy proteins is quite different.

Rapid characterization of thermoelectric properties of composition spread (La 1− xCa x)VO 3 films

Vanadium oxides possess various interesting properties due to multivalence of a vanadium atom and attract our interest as a target material for the exploration of new applications. We investigated vanadates (La 1− x Ca x )VO 3 with a perovskite structure as thermoelectric (TE) materials because heavy electrons in vanadates are expected to generate large thermopower. To proceed the investigation of thermoelectric properties of the composition spread library more efficiently, we devised a new instrument of multi-channel measurement of their thermoelectric properties. The polarity of Seebeck coefficients changed from positive (0≤ x≤0.2) to negative (0.2< x<1.0), and the composition where the film shows the highest power factor in our investigated range is around pure LaVO 3 ( x≈0).

Dynamic viscoelastic properties of spread monostearin monolayer in the presence of glycine

The monostearin monolayer at the air-aqueous interface is more expanded in presence of glycine and at higher temperature from both the surface pressure—area per molecule ( π– A) isotherms and static elasticity—surface pressure ( E s – π) curves. The dilational viscoelastic properties of monostearin monolayer spread on the subphase of glycine solution have been determined by the dynamic oscillation method and discussed as a function of surface pressure, temperature, and frequency. At the frequency of 50 mHz, the monostearin monolayer on pure water shows negative dilational viscosity and is viscoelastic at some surface pressures, while the monostearin monolayer in the presence of glycine is nearly elastic over a wide range of surface pressure, especially at 25 °C. Both positive and negative loss angle tangent can be deduced as a function of surface pressure. The negative dilational viscosity can be attributed to the phase transitions induced by the propagation of the surface waves during the dynamic oscillation. It can be convinced that the interactions between monostearin and glycine play an important role in the formation and rheological behavior of the monolayer. On the other hand, temperature has effect on the dilational elasticity and the dilational viscosity of the monostearin monolayer in different extents. Furthermore, at the surface pressure of 20 mN/m, the monostearin monolayer on the glycine solution at 18 °C is essentially elastic at lower frequency (<100 MHz) and shows viscoelastic behavior at higher frequency. These phenomena should be associated with the complicated monolayer structure and structural reorganization due to the interactions between monostearin and glycine in presence of glycine.

Experimental analysis of the joint statistical properties of azimuth spread, delay spread, and shadow fading

Empirical results characterizing the joint statistical properties of the local azimuth spread (AS), the local delay spread (DS), and the shadow (slow) fading component are presented. Measurement data from typical urban, bad urban, and suburban (SU) environments have been analyzed. It is found that a log-normal distribution accurately fits the distribution function of all the investigated parameters. The spatial autocorrelation function of both AS, DS, and shadow fading can be modeled with an exponential decay function. However, for SU environments the spatial autocorrelation function is better characterized by a composite of two exponential decaying functions. A positive cross correlation is found between the AS and the DS, while both parameters are negatively correlated with shadow fading. All essential parameters required for the implementation of a simulation model considering the joint statistical properties of the AS, DS, and shadow fading are provided.

Structural and Dynamic Properties of Milk Proteins Spread at the Air–Water Interface

We have studied the effect of monolayer structure on dilatational characteristics (surface dilatational modulus and its elastic and viscous components) of protein monolayers (β-casein, caseinate, and whey protein isolate (WPI) spread on the air–water interface, at 20°C, and at pH 5 and 7. The stress response to compression–expansion sinusoidal deformation of the interface in a modified Wilhelmy-type trough with two oscillating barriers was measured as a function of deformation amplitude (within the range of 1–20% of the initial area), frequency (within the range of 1–300 mHz), and superficial density (within the range of 1–8 mg/m2). The same experimental device coupled with Brewster angle microscopy makes it possible to determine the structure, morphology, and relative reflectivity of the monolayer. The monolayer structure and, especially, the conditions at which the monolayer collapses determine the viscoelastic behavior of the monolayer and the linear response of the stress to area deformation. The nonlinear viscoelastic behavior of the interface has been associated with the protein monolayer collapse. It was found not only that the dilatational modulus is determined by the interactions between spread molecules (which depend on the surface density) but also that the structure of the proteins spread on the monolayer also plays an important role.

Response properties of the refractory auditory nerve fiber.

The refractory characteristics of auditory nerve fibers limit their ability to accurately encode temporal information. Therefore, they are relevant to the design of cochlear prostheses. It is also possible that the refractory property could be exploited by prosthetic devices to improve information transfer, as refractoriness may enhance the nerve's stochastic properties. Furthermore, refractory data are needed for the development of accurate computational models of auditory nerve fibers. We applied a two-pulse forward-masking paradigm to a feline model of the human auditory nerve to assess refractory properties of single fibers. Each fiber was driven to refractoriness by a single (masker) current pulse delivered intracochlearly. Properties of firing efficiency, latency, jitter, spike amplitude, and relative spread (a measure of dynamic range and stochasticity) were examined by exciting fibers with a second (probe) pulse and systematically varying the masker-probe interval (MPI). Responses to monophasic cathodic current pulses were analyzed. We estimated the mean absolute refractory period to be about 330 micros and the mean recovery time constant to be about 410 micros. A significant proportion of fibers (13 of 34) responded to the probe pulse with MPIs as short as 500 micros. Spike amplitude decreased with decreasing MPI, a finding relevant to the development of computational nerve-fiber models, interpretation of gross evoked potentials, and models of more central neural processing. A small mean decrement in spike jitter was noted at small MPI values. Some trends (such as spike latency-vs-MPI) varied across fibers, suggesting that sites of excitation varied across fibers. Relative spread was found to increase with decreasing MPI values, providing direct evidence that stochastic properties of fibers are altered under conditions of refractoriness.

Interfacial Properties of Gluten Monolayers Spread on Various Chloride Salt Solutions. Effects of Electrolytes, Salt Concentrations, and Temperature

The interfacial behavior of gluten powder spread as a monolayer on aqueous phases containing various chloride salts was studied. The presence of electrolytes at low concentrations reduced the expansion and stability of the gluten monolayers compared to the results obtained with pure water. At low salt concentrations, no effect of the electrolyte nature was detectable (compression curves were superimposed for Na+, K+, and Ca2+). However, when salt concentrations increased from 0.05 to 0.5 M, the influence of the electrolyte nature on gluten film expansion appeared clearly. Divalent cations (Ca2+) gave films with greater expansion than monovalent cations (K+, Na+). Between the monovalent cations, Na+ had a greater effect on gluten film expansion than did K+. Gluten monolayer expansion evaluated by limiting the area (A0) passed through a minimum when the salt concentrations increased from 0 to 0.5 M. The temperature also influenced the behavior of gluten monolayers as attested by A0 and film elasticity value...

Rheological Properties of Spread

Rheological Properties of Spread

Effects of horizontal cell network architecture on signal spread in the turtle outer retina. experiments and simulations

In the Pseudemys turtle retina five functionally distinct, electrically coupled networks of horizontal cells distribute signals in the outer plexiform layer. These networks differ significantly in their architecture, as determined by intracellular labeling with Neurobiotin after physiological recording and identification. The density of H1 horizontal cells is highest, ranging around 1800 cells/mm 2 at approximately 2.3 mm eccentricity. H1 horizontal cell somata are connected via 6–10 thin, short dendrites. The H1 horizontal cell axon terminal network is composed of thick axon terminals, forming a three-dimensional, sheath-like structure. Networks of coupled H2 and H3 horizontal cells have cell densities of around 210 cells/mm 2 and 350 cells/mm 2 respectively, at the same eccentricity of 2.3 mm. Cell bodies are connected with 6–12 long, thin dendrites. Here we report for the first time H4 horizontal cell networks. Cell density is approximately 970 cells/mm 2 at 2 mm eccentricity, and cell bodies are connected with 6–10 thin, short dendrites. General properties of passive voltage spread were compared for three of these horizontal cell networks using NeuronC. Realistic network architectures were obtained by digitizing the intracellularly labeled networks, respectively. One network obtained from coupled H1 horizontal cell bodies, one from coupled H1 horizontal cell axon terminals, and one from H2 horizontal cells were simulated. These three realistic networks were compared with an artificial, electrically coupled regular triangular network. Passive signal spread in these networks strongly depended on the exact network architecture using otherwise identical parameters. Changes in coupling strength affected signal spread in these networks differently. As in the experimental situation, changes in synaptic conductance influenced signal spread. Some principal effects of extensively coupled horizontal cells on photoreceptor signal processing were simulated with one type of photoreceptor connected by telodendria, synapsing onto an underlying triangular network and receiving feedback synapses. Under certain conditions, spatial information is coded in single photoreceptors. This was also the case in the experimental situation. In the simulation, spatial filter adjustment for optimal spatial coding in photoreceptors can be achieved by changing coupling strength in the horizontal cell network.

Optimizing Low Fat Peanut Spread Containing Sucrose Polyester

ABSTRACTMixture experimental design was used to model the formulation of a low fat peanut spread based on textural profile analysis. Emulsifier was the important factor affecting physical properties of the low fat peanut spread. Sucrose polyester (SPE) contributed only the oily attribute to the product and did not significantly affect physical properties. The optimum combination was 1% salt, 6% corn syrup solids, 2.6% emulsifier, 23.9% SPE, and 66.5% ground defatted peanuts adjusted to 40% peanut oil. The fat content of the optimum sample was 26.6%.

Surface Properties of Didodecyldimethylammonium Bromide Adsorbed and Spread at the Water/Air Interface

The treatment of a two-dimensional system of molecules of different molecular sizes, adapted from statistical thermodynamics, is used to derive parameters which can be related to the interaction between molecules of didodecyldimethylammonium bromide (DDAB) and water. The surface behavior of molecules of DDAB adsorbed and spread at the water/air interface is presented.

A Simple Approach to Valuing Risky Fixed and Floating Rate Debt

ABSTRACTWe develop a simple approach to valuing risky corporate debt that incorporates both default and interest rate risk. We use this approach to derive simple closed‐form valuation expressions for fixed and floating rate debt. The model provides a number of interesting new insights about pricing and hedging corporate debt securities. For example, we find that the correlation between default risk and the interest rate has a significant effect on the properties of the credit spread. Using Moody's corporate bond yield data, we find that credit spreads are negatively related to interest rates and that durations of risky bonds depend on the correlation with interest rates. This empirical evidence is consistent with the implications of the valuation model.

Dilatational Properties of Poly(DL-lactic acid) and Bovine Serum Albumin Monolayers Spread at the Air/Water Interface

Dynamic behavior of monolayers of a biodegradable polymer (poly(D,L-lactic acid), PLA50) and a protein (bovine serum albumin, BSA) spread at the air/water interface are studied to clarify the organization of the films with regard to the composition and the state of compression. A rheological approach based on the Maxwell's model was found to be useful to discriminate the influence of each constituent in the monolayer. Before the transition phase of PLA50, rheological properties of the mixed monolayer are governed by the PLA50 which constitutes probably the continuous phase of the system. During the transition phase of PLA50, condensation of the PLA50 segments allow the formation ofa continuous phase mainly constituted from BSA. After the transition phase of PLA50, rheological properties of the mixed monolayer were shown to be identical to the properties of a pure BSA monolayer. This indicates that BSA is present between PLA50 aggregates and prevents the connection of these domains at least until the higher studied pressure (i.e. 21 mN/m). The obtained results suggest that BSA could be an efficient stabilizer of the interfacial region during preparation of PLA50 particles by an emulsion technique.

Surface Viscoelasticity of β-Casein Monolayers at the Air/Water Interface by Electrocapillary Wave Diffraction

The surface viscoelastic properties of the protein β-casein spread and adsorbed as a monolayer at the air/water interface have been determined using the electrocapillary wave diffraction (ECWD) technique over the wave frequency range of 0.1 to 4.0 kHz. Up to a surface concentration of 1.7 mg/m2, at a surface pressure of 10.4 mN/m, the viscoelastic properties of adsorbed and spread monolayers appear to be identical. Significant increases in surface elasticity, ϵ, and surface viscosity, κ, and the loss tangent, tan δ, occur when the surface concentration just exceeds 1.0 mg/m2, the point at which β-casein appears to exist with all of its amino acid residues at the interface in the form of trains. In agreement with earlier proposals by Graham and Phillips, the significant changes in viscoelasticity at surface concentrations above 1.0 mg/m2 are attributed to the extension of some amino acid residues into the underlying aqueous phase.

Pressure anisotropy and orientational order of a polydiacetylene monolayer and its use as a template for vacuum deposition

The mechanical properties of a polydiacetylene monolayer spread on water have been studied using a surface wave probe. The coil-to-rod transition and the molecular orientational ordering, both induced by the film compression, were found to be two distinct processes. A strong correlation between the stress anisotrophy and the orientational order was found. The monolayers on water were transferred onto solid supports, which in turn were used as substrates for vacuum evaporation of another diacetylene. A semiquantitative transfer of the orientational order from the Langmuir-Blodgett monolayer to the vacuum-deposited film was confirmed.

Photorefraction of the living eye: a model for linear knife edge photoscreening

A computer model is developed to explain colored artifacts in pupil images of the living human eye formed by the linear knife edge photoscreener. An approximate expression for the RGB irradiances recorded by the photoscreener is derived by using the statistical properties of the line spread functions that characterize the source, the aberrations of the eye, and the reflecting properties of the retina. The pupil image for each color is shown to be very much a map of the deviations perpendicular to the knife edge imposed on rays by an equivalent aberration plate, and the overall response of the photoscreener to specific aberrations of the eye is cataloged for errors of accommodation and chromatic aberration, spherical aberration, astigmatism, and tear bands.

Ellipsometric studies of rod outer segment phospholipids at the nitrogen-water interface

Ellipsometry is an optical method which uses the principle that the state of polarization of polarized light changes on reflection at an interface. We have constructed a null ellipsometer for the study of the optical properties of monomolecular films of biological interest at the nitrogen-water interface. With this apparatus we have reproduced the known ellipsometric properties of arachidic acid spread on acidic aqueous solution. Then, we have performed surface potential, surface pressure and ellipsometric measurements of PC (18:1) and rod outer segment phospholipids, i.e. PE ros , PC ros and PS ros , at the nitrogen-water interface. Based on literature refractive indices data, results provide information about the thickness of a lipid film in the close-packed region. Pertinent information about molecular organization of the film is deduced from the close relationship observed between surface potential and ellipsometric isotherms. The importance of these results on the discal membrane structure and function is discussed.