Analytic processing elicits right ear superiority in monaurally presented speech

Experiments were designed to assess the performance of an intracorporeal (abdominal) left ventricular assist device (ALVAD) in the presence of induced tachycardias, multiple premature ventricular contractions (PVC's), and ventricular fibrillation in calves. Performance criteria were the degree of left ventricular unloading and the per cent cardiac output assumed by the ALVAD. During synchronous pumping, left ventricular unloading was complete and the entire cardiac output was captured by the device. During induced tachycardias up to rates of 120 beats per minute, these degrees of performance were maintained. At rates in excess of 120 beats per minute, performance declined due to decreased biologic stroke volumes and prosthetic filling times. In the presence of induced PVC's, performance during synchronous pumping decreased because of erratic R-wave sensing. Left ventricular unloading was complete but irregular, and the total cardiac output was captured. When asynchronous pumping was utilized, mean left ventricular systolic pressures increased, but total cardiac output was still captured. During induced ventricular fibrillation, ALVAD actuation maintained cardiac outputs equal to control values for periods up to 5 1/2 hours. These experiments indicate that, during normal sinus rhythm, synchronous pumping is optimal; asynchronous pumping is optimal during complex dysrhythmias; and either can be utilized to support the circulation with varying degrees of left ventricular unloading.     

Comments on “On amplitude and frequency demodulation usingenergy operators”

The authors comment that while testing some of the results obtained by Maragos, Kaiser and Quatieri (see ibid., vol.41, no.4, p.1532-50, 1993) with a discrete FM signal of the form x(n)=Acos(φ(n)) where φ(n)=Ω_cn+Ω_m /Ω_fsin(Ω_fn)+&thetas; they noticed that the error in the instantaneous frequency increased as Ω_f increased. One would hope that frequency tracking of a constant frequency sinusoidal signal would be very accurate. However, this does not agree with one of their proposition as there is an error in its proof     

In vivo color stability of resin composite veneers and acrylic resin teeth in removable partial dentures

A new core-in-cup tablet that is manufactured from a novel adjustable punch, has been formulated and evaluated for its ability to release with subsequent absorption of theophylline via a zero-order rate of absorption. The core-in-cup tablets were compared with core only tablets and immediate release capsules. Pharmacokinetic parameters used to test the effectiveness of the formulations included, elimination rate, rate and kinetic order of absorption, relative availability as compared with an immediate release capsule of pure theophylline, and percentage area under the curve fluctuation (%AUCF) at steady state. The correlation coefficient, Akaike's information criterion (AIC) and the F-ratio probability were used to test the applicability of a zero-order, first-order, or square root of time model, for the rate of release of theophylline from the core-in-cup and core only tablets. The zero-order rate model was most applicable to the core-in-cup tablet, whereas the square root of time release model was most applicable to the core only tablet. The average %AUCF for the core-in-cup tablet was 9.26+/-3.15 while that for the core only tablet was 16.19+/-2.37 (p = 0.0545). The results of this study suggest that the core-in-cup tablet is a versatile zero-order release rate dosage form that are simple to produce.     

The effect of surfactants on the interfacial tension of frying fat

Interfacial tension (IFT) between fat and water was measured as a means of evaluating fats used for frying. The Du Noüy ring method was used with a tensiometer to obtain IFT. The IFT of donut frying fats, which were diluted 1:1 with unused fat, decreased with increasing frying time from 21 mN/m in unused fat to 5 mN/m in fat at the point of discard. To determine which individual chemical components in donut frying fat are responsible for the decreased IFT, various surfactants were added. The addition of surfactants to the water phase (phosphatidylcholine, sodium oleate, and sodium chloride) or oil phase (monoacylglycerols, diacylglycerols, and fatty acids) had varying effects on the IFT of soybean oil against water at 25 ± 0.1°C. The IFT decreased with increasing concentration of monoacylglycerols, sodium oleate, phosphatidylcholine, and sodium chloride. Sodium oleate was the most effective agent in lowering IFT, reducing it almost to zero at a concentration of 0.1%. At a concentration of 0.2%, monoacylglycerols lowered IFT of fresh soybean oil by 14% (monolinolein), 22% (monoolein), and 26% (monostearin). Egg lecithin lowered the IFT by 42%. These surfactants changed the IFT of fresh soybean oil by their adsorption at the oil/water interface. Although sodium chloride is not a surfactantper se, it lowered IFT by salting out surfactants from the aqueous phase onto the interface. The addition of diacylglycerols or fatty acids had virtually no effect on IFT. Presented at the 84th AOCS Annual Meeting & Expo in Anaheim, California, May 1992.     

A calibration scheme for imperfect quantizers

This paper considers the calibration of imperfect quantizers, or analog-to-digital converters (ADCs). We present a method working purely in the digital domain, suitable e.g., for calibration of ADCs from output data only. The proposed method is based on a linear-filter reconstruction of an analog calibration signal. The reconstructed version of the calibration signal is employed in designing an updated quantization table, with the aim of improving the overall performance. Experiments demonstrate gains in terms of spurious-free dynamic range and signal-to-noise and distortion ratio (SNDR)     

In vitro evaluation of artificial ageing on surface properties and early Candida albicans adhesion to prosthetic resins

Objective The aim of this in vitro study was to examine potential changes and influences of prosthetic resin surface properties on Candida albicans adhesion after surface treatment or artificial ageing. Materials and methods Standardized specimens of a denture base resin and a veneering composite were prepared, polished, and randomly subjected to different surface roughness treatments or artificial ageing protocols (storage in ethanol or artificial saliva for 7/90 d, thermocycling). Surface roughness (Ra) and surface free energy were determined prior and after each treatment. Specimens were incubated with phosphate buffered saline or whole saliva for 2 h at 37°C, and later with Candida albicans suspension (2.5 h, 37°C). Adherent viable fungi were quantified using a bioluminescence assay. Results Artifical ageing did not affect substratum surface roughness, yet slight increases in substratum surface free energy and significant increases in Candida albicans adhesion were observed. Saliva coating marginally influenced Candida albicans adherence to reference and surface treated specimens, yet more pronounced differences in Candida albicans adhesion between the various artificially aged specimens were found. Conclusion No correlation between substratum surface roughness or surface free energy and Candida albicans adhesion could be established.     

Electron beam irradiation of denture base materials

Electron beam irradiation can be used to influence the properties of polymers. It was the aim of this study to investigate whether PMMA denture base materials can benefit from irradiation in order to have increased fracture toughness, work of fracture or hardness. Rectangular specimens of heat-and auto-curing denture base materials were electron beam irradiated (post-cured) with 25, 100 and 200 kGy using an electron acceleration of 10 MeV or 4.5 MeV respectively. Fracture toughness, work of fracture, Vickers hardness and colour changes were measured and compared with not-irradiated specimens.The toughness, work of fracture and hardness increased using 10 MeV with a dose of 25 kGy and with 100 kGy using 4.5 MeV. However, the clinical use may not benefit from the observed small changes. Higher dosage (200 kGy) decreased the values significantly. The colour changes reached a level which was found to be not clinically acceptable. Conclusion: PMMA denture base materials do not benefit from post-curing with electron beam irradiation.     

De novo design of the hydrophobic core of ubiquitin

We have previously reported the development and evaluation of a computational program to assist in the design of hydrophobic cores of proteins. In an effort to investigate the role of core packing in protein structure, we have used this program, referred to as Repacking of Cores (ROC), to design several variants of the protein ubiquitin. Nine ubiquitin variants containing from three to eight hydrophobic core mutations were constructed, purified, and characterized in terms of their stability and their ability to adopt a uniquely folded native-like conformation. In general, designed ubiquitin variants are more stable than control variants in which the hydrophobic core was chosen randomly. However, in contrast to previous results with 434 cro, all designs are destabilized relative to the wild-type (WT) protein. This raises the possibility that beta-sheet structures have more stringent packing requirements than alpha-helical proteins. A more striking observation is that all variants, including random controls, adopt fairly well-defined conformations, regardless of their stability. This result supports conclusions from the cro studies that non-core residues contribute significantly to the conformational uniqueness of these proteins while core packing largely affects protein stability and has less impact on the nature or uniqueness of the fold. Concurrent with the above work, we used stability data on the nine ubiquitin variants to evaluate and improve the predictive ability of our core packing algorithm. Additional versions of the program were generated that differ in potential function parameters and sampling of side chain conformers. Reasonable correlations between experimental and predicted stabilities suggest the program will be useful in future studies to design variants with stabilities closer to that of the native protein. Taken together, the present study provides further clarification of the role of specific packing interactions in protein structure and stability, and demonstrates the benefit of using systematic computational methods to predict core packing arrangements for the design of proteins.     

Effect of water quality on degumming and stability of soybean oil

Solvent-extracted crude soybean oil was degummed with deionized distilled water containing various amounts of CaCO₃−MgCO₃ FeCl₂, and NaCl. The total phosphorus content remaining in the degummed oil was determined and the peroxide value of the degummed oil held at 98–101 C was measured daily for 10 days. The results were compared statistically with those from oil degummed with deionized distilled water as a control. It was found that 250 mg/L of CaCO₃−MgCO₃ significantly reduced the efficiency of the degumming process. FeCl₂ at concentrations of 150 and 250 μg/L and NaCl at 300 mg/L resulted in the removal of more phosphorus than the control at the 5% level of significance. Generally, the stability of the degummed oils decreased as the salt concentrations increased. The rate of oxidation was greater for oils degummed in the presence of FeCl₂ than of NaCl and CaCO₃−MgCO₃ under the same conditions.     

Radiation Resistance of Listeria monocytogenes in the Presence or Absence of Sodium Erythorbate

ABSTRACT: Listeria monocytogenes is a common contaminant of ready-to-eat meat products that can be eliminated by low dose ionizing radiation. Sodium erythorbate (SE), an antioxidant, is commonly included in cured meat emulsions or applied to the surfaces of cured meats as a solution prior to packaging. The radiation resistance (D_γ) of L. monocytogenes increased when suspended in SE solutions of 0.1% and greater. However, no differences in D_γ, which ranged from 0.67 kGy to 0.70 kGy, were observed when L. monocytogenes was inoculated onto cooked cured meat products (frankfurters or bologna slices) which contained no SE, 0.05% SE in the emulsion, or a 10% SE solution applied to the product surface. Surface antioxidant power of the cured meats did not reach a level sufficient to protect L. monocytogenes against the lethal effects of ionizing radiation. Therefore, the industrial practice of applying SE to the surfaces of cured meat products would not compromise the efficacy of irradiation as an antimicrobial process.