Transgenic mice expressing human ApoB95 and ApoB97. Evidence that sequences within the carboxyl-terminal portion of human apoB100 are important for the assembly of lipoprotein

The structural features of apolipoprotein (apo) B that are important for its covalent linkage to apo(a) to form lipoprotein(a) (Lp(a)) are incompletely understood. Although apoB100 cysteine 4326 is required for the disulfide linkage with apo(a), other structural features, aside from a single free cysteine residue, must be important for apoB's initial interaction with apo(a) and for facilitating the formation of the disulfide bond. To determine if sequences carboxyl-terminal to cysteine 4326 affect the efficiency of Lp(a) formation, we used "pop-in, pop-out" gene targeting in a human apoB yeast artificial chromosome to introduce nonsense mutations into exon 29 of the apoB gene. The mutant yeast artificial chromosomes, which coded for the truncated versions of human apoB, apoB95, and apoB97, were then used to express these mutant forms of apoB in transgenic mice. As judged by in vitro assays of Lp(a) formation, apoB95 (4330 amino acids) formed a small amount of Lp(a) but did so slowly. In contrast, apoB97 (4397 amino acids) formed Lp(a) rapidly, although not quite as rapidly as the full-length apoB100 (4536 amino acids). These results were supported by an analysis of double-transgenic mice expressing both human apo(a) and either apoB95 or apoB97. In mice expressing both apoB95 and apo(a), there was only a trace amount of Lp(a) in the plasma, and most of the apo(a) was free, whereas in mice expressing both apoB97 and apo(a), virtually all of the apo(a) was bound to apoB97 in the form of Lp(a). These results show that sequences carboxyl-terminal to apoB95 (amino acids 4331-4536) are not absolutely required for Lp(a) formation, but this segment of the apoB molecule, particularly residues 4331-4397, is necessary for the efficient assembly of Lp(a).     

Development of carbon–manganese–chromium steels for automotive hot stamping technologies

The hot stamping potential of three commercial carbon–manganese–chromium steels was demonstrated. The steels were selected with the intention of producing ultrahigh strength ferritic–martensitic dual phase microstructures from hot stamping heat treatment, exhibiting superior tensile properties for ‘impact energy absorptive’ crash performance compared to the conventional carbon–manganese–boron steel for automotive hot stamping technologies, 22MnB5. Compared to 22MnB5, each of the carbon–manganese–chromium steels provided at least twice the total elongation, yet with a relatively small loss to ultimate tensile strength. It was concluded that the carbon–manganese–chromium steels provide superior tensile properties for impact energy absorptive crash performance, while exhibiting ‘lean’ chemical compositions compared to previously investigated steels with similar aims and offer opportunities for use in the ‘tailor welded blank’ concept.     

Primary non-Hodgkin''s lymphoma of the larynx in an AIDS patient

BACKGROUND AND OBJECTIVES: Interscalene brachial plexus block is a useful technique to provide anesthesia and analgesia for the shoulder and proximal upper extremity. The initial needle direction at the interscalene groove has been described as being "perpendicular to the skin in every plane" (1). A cross-sectional (axial) approach may offer a more easily conceptualized directed needle placement. The purpose of this study is to define the cross-sectional anatomy and idealized needle angles important to interscalene brachial plexus block. METHODS: Following IRB approval, 50 patients were studied. Cross-sectional volume coil T1-weighted magnetic resonance images (MRI) were obtained from 50 patients undergoing cervical region imaging for other reasons. At the interscalene groove, a simulated needle path to contact the ventral rami or trunks of the brachial plexus was approximated at the level of C6 or C6-C7 interspace. The angle of this needle path intersecting the sagittal plane was recorded for each patient. RESULTS: The mean angle of the simulated needle path relative to sagittal plane was determined to be 61.1 +/- 6.1 degrees (range, 50-78 degrees). In 13 of 50 (26%) MRI scans, the cervical nerve roots were not visualized at the level of C6 and were measured at the C6-C7 level. CONCLUSIONS: These findings suggest initial needle placement at the interscalene groove should be angled less perpendicularly relative to the sagittal plane than is often observed. A cross-sectional approach enables more practical visualization of initial needle placement. A more accurate initial needle placement may minimize the number of needle passes necessary to contact the nerve roots, thereby more efficiently obtaining a successful block.     

Situated artificial institutions: stability,consistency, and flexibility in the regulation of agent societies

In multi-agent systems, norms are a usual way to regulate the behaviour of autonomous agents. To be stable in different circumstances, norms are specified using high level terms, abstracting from the particular dynamics of the environment where the agents are situated. However, applying these norms requires a proper link with a concrete environment. Detaching that link from the norms themselves provides stability to the normative regulation but raises consistency and flexibility issues. Consistency is achieved when the abstract norms are coherent with the environment under regulation. Flexibility is achieved when different kinds of norms share the same interpretation about the environmental state. These properties are provided in some current works. However, since they are interrelated, there is not, to our knowledge, a single proposal providing all of them. This paper proposes the situated artificial institution (SAI) model to address these three issues—stability, consistency, and flexibility—by conceiving norms as part of institutions that provide, through the process of constitution, a social interpretation of the environmental state. After the presentation of the formalised model of SAI, a case study is used to illustrate and test this approach.     

Rheology and Particle Packing of Chem- and Phys-Adsorbed, Alkylated Silicon Nitride Powders

Three alcohols with extended carbon chain lengths between ∼1 and 2 nm were chem-adsorbed on a Si₃N₄ powder by reacting with hydroxyl surface groups at temperatures 200°C. Slurry rheology, particle packing density, and body rheology were determined for toluene and dodecane slurries formed with these chem-adsorbed powders. These same properties were determined for slurries where the alcohol was simply added, but not reacted with the powder (phys-adsorbed powders). The viscosities of chem-adsorbed slurries are shear-thinning with longer chains producing lower viscosities at a given shear rate. The relative density of powder compacts produced by pressure filtration (10 MPa) was high (∼0.60) for octadecanol and dodecanol-reacted powders, and lower (∼0.50) for the octanol-reacted powder. When a sufficient amount > 10 times that required for chem-adsorption) of the same alcohol was simply added to the unreacted Si₃N₄ slurry system, the phys adsorbed slurries exhibited similar rheological behavior as the chem-dsorbed slurries, but, unlike chem-adsorbed slurries, their packing densty was lower, and their slurries were destabilized by water vapor. Stress relaxation experiments showed that bodies formed with the octadecanol chem-adsorbed powders were plastic after consolidation, whereas phys-dsorbed bodies were brittle (fractured before flow). All evidence suggests that the short-chained alkyl groups are steric "stabilizers" at small interparticle distances and thus prevent the particles from making surface-surface contact in common organic liquids; i.e., they produce a short-range interparticle, repulsive potential. Chem-adsorbed molecules, but not phys-adsorbed molecules, persist during particle packing and in moist environments.     

A simulation tool for performance evaluation of the IBM 360/75

In this paper we present some results obtained from using simulation as a tool for evaluating alternative methods of improving system performance in network computers. We begin by describing a GPSS model which was developed to evaluate the current computer center operations at the University of Illinois. While using actual data from the center to verify that the model accurately predicts each job's total time in the system, we evaluate the resource utilization within the center. Then we use the simulator to show that a proposed dynamic priority assignment algorithm yields better throughput than the existing algorithm while maintaining a higher level of CPU and memory utilization. Next, turning our attention to a hypothetical network of three centers, we use a generalization of our model to demonstrate the effects of load leveling between centers on the total system throughput. Here we also explore the merits of pay-for-priority schemes in both a single center and in a network of three centers.     

Packing Density of Composite Powder Mixtures

A model of particle packing in binary composite systems is developed. The effects of both inclusion surfaces and touching inclusions on the packing density are taken into account. To implement the model, a statistical approach is used to determine the number of inclusion contacts as a function of inclusion content. The statistical approach indicates that the average number of inclusion contacts is a linear function of the inclusion volume fraction, a result which agrees very well with independent computer simulations. The model suggests that the packing efficiency, defined by the ratio of the packing density to the ideal packing density (as originally derived by Furnas), is governed by the inclusion volume fraction ( f_i ) and the particle to inclusion size ratio ( r ). Good agreement is obtained between the theory and experimental literature data.     

The composition of the oil extracted from 14 different varieties ofAndropogon Sorghum var.Vulgaris

Summary Fourteen varieties ofAndropogon Sorghum var.vulgaris were subjected to fractional solvent extraction. An average yield of 0.32% wax and 2.76% of oil was obtained. The 14 sorghum grain oils varied from a light amber to green in color. They had an average refractive index of 1.4695 at 25° C. and contained 2.51% nonsaponifiable matter. The mixed fatty acids obtained from the oils had an average melting point of 28.9° C., a neutralization equivalent of 278.8, iodine value of 120.8, and thiocyanogen value of 81.5. The composition of the mixed fatty acids were calculated from the iodine and thiocyanogen values. The mixed fatty acids contained an average of 46.5% linoleic, 39.5% oleic, 7.8% palmitic, and 4.7% stearic acid. Financial support for this work was furnished by The Kansas Industrial Development Commission. Contribution No. 314 from The Department of Chemistry.     

Substitutability of fractionated beef tallow for other fats and oils in the food and confectionery industries: An economic evaluation

The United States is the most important beef tallow producer in the world, supplying ca. 5.5 billion pounds annually. Approximately half of this beef tallow is exported at relatively low prices when compared to other fats and oils. Only ca. 10% of the total is used in domestic edible products. On the other hand, cocoa butter, coconut oil, palm oil, and palmkernel oil are imported oils whose demand for use in food and confectionery products has been increasing over the past few years. The first of these is the most expensive fat in the world. Beef tallow contains specific triglycerides which are also contained in these imported fats and oils. Through modern technology, beef tallow has been fractionated into products which are compatible with or superior to the imported fats and oils. It is visualized that products from fractionated beef tallow can be used as substitutes and extenders to cocoa butter, palm oil, and other fats and oils in the food and confectionery industries. The economic evaluation in this paper, analyzed through time series data and multiple regression techniques, established the past relationships between per capita consumption of confectionery food fat, beef tallow, cocoa butter, adjusted per capita disposable income, and adjusted costs of confectionery, beef tallow, and cocoa butter from 1956 to 1973. The substitutability of fats and oils was evaluated and the potential uses of fractionated beef tallow investigated. Presented in part at the AOCS meeting in Cincinnati, September 1975.