Determinations of nonprotein nitrogen content of cheese whey.

Nonprotein nitrogen in pooled sweet (Cheddar and Dagano) and acid (cottage) wheys was estimated by currently proposed dialysis and chemical precipitation methods. Kjeldahl nitrogen analyses of (a) membrane retentates after water dialysis, and (b) 12% trichloroacetic acid plus .2% phosphotungstic acid filtrates indicated that nonprotein nitrogen values vary significantly with the method of sample preparation. Membrane porosity influence nonprotein nitrogen values for molecular weight cut-offs of 3500, 6000 to 8000 and 12,000 to 14,000. Dialyzable nitrogen values with all membranes were lower than 12% trichloroacetic acid soluble nitrogen for both wheys and higher than the 12% trichloroacetic acid + .2% phosphotungstic acid soluble nitrogen for all but the 3500 molecular weight cut-off membrane. The dialyzable nonprotein nitrogen fraction was heterogeneous but more that 80% was less than 3500 in molecular weight.     

Electrophysiology of atrial fibrillation and its prevention by coronary sinus pacing

OBJECTIVES: Prehospital providers are often unable to obtain intravenous (i.v.) access in cardiac arrest victims. While several drugs can be administered via the endotracheal (ET) route, serum drug levels are lower than those obtained with the i.v. route. The authors hypothesized that a 90-degree torso tilt after ET drug administration would increase drug levels. METHODS: A randomized, prospective, unblinded laboratory trial was conducted. Twenty-three mixed-breed domestic swine (20-25 kg) were sedated, anesthetized, instrumented, shocked into cardiac arrest, and randomized into three groups. Lidocaine was administered either i.v. (1.5 mg/kg), traditional ET (4.5 mg/kg), or ET followed by a 5-second 90-degree upright torso tilt (4.5 mg/kg). While standard CPR was performed, lidocaine levels were obtained at 0.5, 1, 2, 3, 4, and 5 minutes after administration. Repeated-measures ANOVA was used for data analysis (alpha = 0.05). RESULTS: Experimental ET compared with traditional ET administration produced significantly higher levels at all time points except 0.5 minutes. Comparing experimental ET with i.v. administration yielded significantly higher levels for the i.v. route at 0.5 and 1 minute and for the experimental ET route at 4 and 5 minutes. i.v. lidocaine administration resulted in significantly higher levels at 0.5, 1, and 2 minutes when compared with traditional ET administration. CONCLUSIONS: Endotracheal instillation of lidocaine followed by a 90-degree torso tilt resulted in better drug absorption, as evidenced by higher serum lidocaine levels, than did traditional recumbent ET delivery at all but the earliest time point and produced more sustained lidocaine levels than i.v. administration at 4 and 5 minutes. ET drug delivery followed by a 5-second 90-degree torso tilt and the mechanisms for this enhanced absorption warrant further investigation.     

Procainamide induced change of the width of the zone of entrainment and its relation to the inducibility of reentrant ventricular tachycardia

Procainamide depresses conduction velocity and prolongs refractoriness in myocardium responsible for reentrant VT, but the mechanism by which the induction of VT is suppressed after procainamide administration remains to be determined. In the present study, the relationship between electrophysiological parameters and the noninducibility of VT was assessed during procainamide therapy with a special reference to the change of an excitable gap. Clinically documented monomorphic sustained VT was induced in 30 patients and, utilizing the phenomenon of transient entrainment, the zone of entrainment was measured as the difference between the cycle length of VT and the longest paced cycle length interrupting VT (block cycle length) which was determined as the paced cycle length decreased in steps of 10 ms, and used as an index of the excitable gap. The effective refractory period was measured at the pacing site and the paced QRS duration was used as an index of the global conduction time in the ventricle. The cycle length of VT, the block cycle length, and the width of the zone of entrainment were determined and compared between the responders and nonresponders. In 15 patients, these parameters were determined at the intermediate dose and related to subsequent noninducibility at the final dose. At the final doses of procainamide, VT was suppressed in 8 (26.7%) of 30 patients. However, the cycle length of VT, the block cycle length, and the width of the zone of entrainment were unable to predict the drug efficacy, i.e., noninducibility. The change in the effective refractory period at the pacing site or the width of the paced QRS duration was not different between the responders and nonresponders. Among the variables, only the width of the zone of entrainment showed a significant narrowing in the responders at the intermediate dose of procainamide, and it was smaller than that of the nonresponders. The significant narrowing of the width of the zone of entrainment was associated with the subsequent noninducibility of VT at the final dose. The present study showed that the baseline cycle length of VT, the block cycle length, the drug induced change of the effective refractory period, or the paced QRS duration was not a predictor of the noninducibility after procainamide administration. However, a significant narrowing of the width of the zone of entrainment at the intermediate dose was associated with the noninducibility of VT at the final dose.     

A smart manufacturing methodology for real time chemical process diagnosis using causal link assessment

Industrial chemical plant diagnosis is the task of analyzing process data to sufficiently pinpoint the causes of abnormal events as fast and as accurately as possible so corrective action can be taken in a timely manner. The need to identify failures explicitly and support human centered decision making becomes pronounced for enterprises. Qualitative diagnostic models offer robustness in capturing diagnostic behaviors when there is little or no data on fault conditions. This article develops, analyzes, and demonstrates a qualitative diagnostic methodology called Causal Link Assessment (CLA). CLA avoids the drawbacks of other methodologies while leveraging several new concepts that include dynamic pattern generation, single time step modeling with multitime step interpretation, and discretized, low granularity dynamic modeling. CLA is demonstrated for an existing ethylene production facility. Model building, robustness, reusability, unaccounted for faults and failures and alignment with emerging Smart Manufacturing infrastructure concepts are discussed. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3420–3431, 2016     

Sprint start instrumentation

A prototype instrument has been developed to measure the forces generated on the starting blocks and the speed of a sprinter at the start of a sprint event. The starting block forces can be resolved into horizontal and vertical components for each foot, or the various combinations of these four forces can be calculated and displayed along with the resultant angle. The speed of the sprinter is measured by means of a Doppler microwave technique (radar gun). Both static and dynamic tests have been used to calibrate the force transducers and to verify their functional bandwidth. The speed measurement technique has been validated by four independent procedures: measurement of a constant velocity object; measurement of an object undergoing constant acceleration; determination of distance travelled by an athlete; and comparison with high-speed cinematography. Both the force and speed profiles can be displayed immediately on the screen of a microcomputer for feedback to the coach and athlete during training sessions     

Function in Device Representation

We explore the meanings of the terms ‘structure’, ‘behaviour’, and, especially, ‘function’ in engineering practice. Computers provide great assistance in calculation tasks in engineering practice, but they also have great potential for helping with reasoning tasks. However, realising this vision requires precision in representing engineering knowledge, in which the terms mentioned above play a central role. We start with a simple ontology for representing objects and causal interactions between objects. Using this ontology, we investigate a range of meanings for the terms of interest. Specifically, we distinguish between function as effect on the environment, and a device-centred view of device function. In the former view, function is seen as an intended or desired role that an artifact plays in its environment. We identify an important concept called mode of deployment that is often left implicit, but whose explicit representation is necessary for correct and complete reasoning. We discuss the task of design and design verification in this framework. We end with a discussion that relates needs in the world to functions of artifacts created to satisfy the needs.     

Method of determining nanoparticle core weight

Polymer-coated metal or metal oxide nanoparticles have a variety of uses in industry, biological research, and medicine. Characterization of nanoparticles often includes determination of the dimensions of the electron-dense core by transmission electron microscopy (TEM), with the weight of the core determined from core volume and core density. However, TEM is labor intensive, has a long turnaround time, and uses equipment that is sometimes not readily available. Here we present an alternative method for determining the weight of nanoparticle cores termed the viscosity/light scattering method, which uses (i) measurements of viscosity over a wide concentration range to obtain the partial specific volume, (ii) measurements of particle diameter by light scattering, to obtain the volume of an individual particle, and (iii) the concentration of nanoparticles (w/v). We have applied this method to determine the weights of nanoparticle cores (iron of amino-CLIO and ferritin), the weights of globular proteins (molecular weight of IgG and albumin), and the weight of polystyrene microspheres. The viscosity/light scattering method is nondestructive of the sample and can be performed with a variety of materials on a routine basis.     

Contribution of Penicillium sp. to the Flavors of Brie and Camembert Cheese

Volatile flavor compounds produced by Penicillium caseicolum in domestic and French Brie cheese were identified by gas chromatography-mass spectrometry; they included carbon-5, carbon-7, Carbon-9, carbon-11 methyl ketones, and corresponding secondary alcohols, 2-octanone, 3-octanone, 1-octen-3-ol, 1,5-octadien-3-ol, 1,5-octadien-3-one, and 2-methylisoborneol. Lipoxygenase formation of the eight carbon compounds responsible for the mushroom, plant-like flavors of mold surface-ripened cheeses was enhanced either by the disruption of mold mycelia or the addition of specific ω-3 and ω-6 fatty acid precursors. The occurrence of 8-nonen-2-one in mold-ripened cheeses was associated with the β-oxidative conversion of a specific unsaturated fatty acid resulting from initial lipoxygenase attack on either linoleic or linolenic acids.