Separation of bacterial capsular and lipopolysaccharides by preparative electrophoresis

Preparative gel electrophoresis was used to separate and purify extracellular, capsular and lipopolysaccharides (EPSs, CPSs, and LPSs, respectively) from crude bacterial extracts. The procedure effectively separates CPS from LPSs. In addition discreet size ranges of these various polysaccharides can be isolated. The 'rough' (R-type), 'smooth' (S-type), and 'semi-smooth' LPSs were separated from one another. In addition different size classes of 'semi-smooth', or S-type LPS, can be separated. This procedure was demonstrated for diverse bacterial species, including the soil bacteria Rhizobium fredii, and the enteric bacterial species, Salmonella enteritidis and Proteus mirabilis. In the latter case, it was also possible to separate capsular polysaccharide from its lipid-bound form.     

Implementing the Put Prevention into Practice program

Put Prevention into Practice (PPIP) is a national program designed to improve the delivery of preventive care to patients by all primary care clinicians. It covers the full range of clinical preventive services, including immunizations, screening tests, chemoprophylaxis, and counseling interventions. The materials that comprise this program involve patients, office/clinic systems and staff, and clinicians, including nurse practitioners. The need for preventive care, the barriers to be overcome, the PPIP program, and a strategy for its implementation are delineated. Principles for successful implementation include: high level administrative support, ownership by all the players in the implementation process, a person designated to manage implementation, and an ongoing evaluation/auditing process that provides feedback to clinicians and others participating in the program.     

Dielectric properties of vacuum-deposited bismuth oxide films

The dielectric properties of bismuth oxide films prepared by vacuum deposition have been studied in the frequency range 0.1–10 kHz and the temperature range 90–298.5 K. The capacitances C_p and C_s and the loss factor show dependences on the frequency, temperature and aging of the samples. The loss factor exhibits a flat maximum in its temperature variation curve at about 170 K. Interfacial polarization, which is caused by the excess bismuth and by various defects and impurities, is thought to be the main relaxation mechanism operating in the low frequency region.     

Prediction of the performance of continuous mixers for particulate solids using residence time distributions Part I. Theoretical

A numerical method is proposed for predicting the variance reduction ratio of a continuous mixer using the results of a residence time distribution test. The method can be used for any mixer, whatever its efficiency, and for any form of input into the mixer.     

D- and Z-values of microflora in tuna mince during moist- and dry-heating

Fish and seafood are prone to rapid microbial spoilage, thus adequate care must be taken in drying of fish. The microbial load and its changes during drying and storage are important information in establishing a standard that will ensure food safety. In order to develop drying procedures leading to low safety risk, it is relevant to determine the decimal reduction time (D-value) and the thermal resistance constant (Z-value) during a heating process to identify the effect of temperature on lethality. In the case of drying, microbial changes occurred due to the effects of heat and concentration process. This study was conducted to investigate the changes of endogenous bacterial counts in minced tuna during dry-heating (convection air-drying) and moist-heating (heating in a closed chamber) as a function of temperature. The D-values for total viable counts decreased from 2.52 to 0.26 h for moist-heating and 2.57 to 0.34 h for dry-heating, respectively, when temperature was maintained constant within 60-140°C. In both cases, increasing temperature caused significant decrease in D-values (P<0.05), whereas the effect of heating methods was not significant (P>0.05). Thus the heat resistance characteristics of microorganisms in fresh tuna mince was not depended on the changing medium moisture content.     

Fuzzy logic control of FES rowing exercise in paraplegia

An indoor personal rowing machine (Concept 2 Inc., Morrisville, VT) has been modified for functional electrical stimulation assisted rowing exercise in paraplegia. To successfully perform the rowing maneuver, the voluntarily controlled upper body movements must be coordinated with the movements of the electrically stimulated paralyzed legs. To achieve such coordination, an automatic controller was developed that employs two levels of hierarchy. A high level finite state controller identifies the state or phase of the rowing motion and activates a low-level state-dedicated fuzzy logic controller (FLC) to deliver the electrical stimulation to the paralyzed leg muscles. A pilot study with participation of two paraplegic volunteers showed that FLC spent less muscle energy, and produced smoother rowing maneuvers than the existing On-Off constant-level stimulation controller.     

Rigorous comparison of parabolically tapered and conventional multimode-interference-based 3-dB power splitters in InGaAsP/InP waveguides

Design issues such as optical transmission, interference mechanisms, the splitting ratio, the polarization dependence, and the fabrication tolerances of a compact parabolically tapered multimode-interference (MMI)-based 3-dB power splitter on an InP-based deeply etched ridge waveguide, by use of the finite-element-based beam-propagation method, are presented. The benefits and drawbacks of the use of the tapered structure, in comparison with an untapered MMI-based 3-dB splitter, have also been investigated.     

Thermal and related studies of some zirconia gels

The thermal properties of a number of zirconia gels, prepared with various precipitants, have been studied by thermogravimetry, differential thermal analysis and evolved gas analysis. The results obtained show that ligands derived from the various precipitants are incorporated in these gels and strongly influence their high temperature behaviour. The observed properties are interpreted on the basis of a defect structure involving O^2- vacancies generated through the removal of these ligands at higher temperatures.     

Stochastic meshless analysis of elastic–plastic cracked structures

This paper presents a stochastic mesh-free method for probabilistic fracture-mechanics analysis of nonlinear cracked structures. The method involves enriched element-free Galerkin formulation for calculating the J-integral; statistical models of uncertainties in load, material properties, and crack geometry; and the first-order reliability method (FORM) for predicting probabilistic fracture response and reliability of cracked structures. The sensitivity of fracture parameters with respect to crack size, required for probabilistic analysis, is calculated using a virtual crack extension technique. Numerical examples based on mode-I fracture problems have been presented to illustrate the proposed method. The results from sensitivity analysis indicate that the maximum difference between sensitivity of the J-integral calculated using the proposed method and reference solutions obtained by the finite-difference method is about three percent. The results from reliability analysis show that the probability of fracture initiation using the proposed sensitivity and meshless-based FORM are very accurate when compared with either the finite-element-based Monte Carlo simulation or finite-element-based FORM. Since all gradients are calculated analytically, the reliability analysis of cracks can be performed efficiently using meshless methods. The authors would like to acknowledge the financial support of the U.S. National Science Foundation (NSF) under Award No. CMS-9900196. The NSF program director was Dr. Ken Chong.     

AC electrical conductivity of electron beam evaporated Cu-GeO2 thin cermet films

AC electrical properties of 410 nm think 30 at.wt% Cu-70 at.wt% GeO₂ thin films are reported for the frequency range 10⁴ to 10⁶ Hz and temperature range 150 to 425 K. The loss tangent (tan ) and the dielectric loss (/₀) are found to show striking minima around a cut-off frequency 10⁵ Hz. In the lower frequency range (10⁵ Hz), ₁() ^s T ⁿ is obeyed with s (0 to 0.51) increasing as a function of temperature and n (0.10 to 0.14) showing a very weak temperature dependence. In the higher frequency region (10⁵ Hz), ₁() and /₀ increase sharply leading to the quadratic behavior of ₁() with s equal to 2. These processes are discussed by analyzing an equivalent circuit which shows that at lower frequencies, the effects of series resistance in leads and contacts can be neglected, while at higher frequencies such effect give rise to spurious ² dependance for the conductance. A weakly activated AC conductivity and a frequency exponent s that increases with increasing temperature suggest that the low frequency behavior originates from carrier migration by tunneling process.