Dynex: multiplex ELISA technology

Conventional enzyme-linked immunosorbent assay (ELISA) is a gold standard for screening antibodies and testing for protein or antigen presence. A significant limitation of this assay resides in the fact that only one analyte can be assessed per microplate well. Here, we describe and investigate a new technology consisting of an automated ELISA system in which up to 10 analytes can be measured within one single well, thus improving productivity, accuracy, and repeatability by reducing the amount of human labor required. Another strength of the platform is that a user can load any necessary sets/subsets of beads to perform required assays, with improved flexibility compared to manufactured-loaded arrays for multiplex analysis. We also demonstrate that this system can be used to determine the pathogenicity (i.e., presence of Shiga toxins) and serotype (i.e., Escherichia coli O157) of E. coli isolates.     

Association of IgG1 Antibody Clearance with FcγRIIA Polymorphism and Platelet Count in Infliximab-Treated Patients

The FcγRIIA/CD32A is mainly expressed on platelets, myeloid and several endothelial cells. Its affinity is considered insufficient for allowing significant binding of monomeric IgG, while its H131R polymorphism (histidine > arginine at position 131) influences affinity for multimeric IgG2. Platelet FcγRIIA has been reported to contribute to IgG-containing immune-complexe clearance. Given our finding that platelet FcγRIIA actually binds monomeric IgG, we investigated the role of platelets and FcγRIIA in IgG antibody elimination. We used pharmacokinetics analysis of infliximab (IgG1) in individuals with controlled Crohn’s disease. The influence of platelet count and FcγRIIA polymorphism was quantified by multivariate linear modelling. The infliximab half-life increased with R allele number (13.2, 14.4 and 15.6 days for HH, HR and RR patients, respectively). It decreased with increasing platelet count in R carriers: from ≈20 days (RR) and ≈17 days (HR) at 150 × 10⁹/L, respectively, to ≈13 days (both HR and RR) at 350 × 10⁹/L. Moreover, a flow cytometry assay showed that infliximab and monomeric IgG1 bound efficiently to platelet FcγRIIA H and R allotypes, whereas panitumumab and IgG2 bound poorly to the latter. We propose that infliximab (and presumably any IgG1 antibody) elimination is partly due to an unappreciated mechanism dependent on binding to platelet FcγRIIA, which is probably tuned by its affinity for IgG2.     

Structure–property relationships for sulfonated poly(butylene terephthalate)

Structure–property relationships have been developed for sulfonated poly(butylene terephthalate) copolymers. The compositional variables investigated were sulfonate content, molecular weight, and polymer endgroup composition, and the fundamental polymer properties evaluated were melt viscosity, crystallization kinetics, and impact strength. It was found that all compositional variables significantly affect all of the polymer properties of interest. The most interesting effect is the influence of polymer endgroup composition on polymer properties. The trends indicate that the carboxylic acid endgroups form intermolecular interactions with sodium sulfonate groups, resulting in a decrease in the strength of intermolecular ionic interactions between sodium sulfonate groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4662–4771, 2006     

Combinatorial materials research applied to the development of new surface coatings: II. Process capability analysis of the coating formulation workflow

A combinatorial process has been developed for the high throughput production and evaluation of surface coatings. The workflow designed for the production of arrays of liquid coatings involves the robotic transfer of aliquots of solutions of raw materials to an array of glass vials and mixing of the coatings using an unconventional magnetic stirring process. An investigation of the capability of the workflow to accurately and repeatedly prepare coating arrays was conducted as a function of solution viscosity and aliquot size. In addition, mixing capability was evaluated as a function of solution viscosity, total solution volume, and mechanism of stirring. Overall, the results of the study indicated that adequate accuracy and repeatability of the coating preparation process can be achieved as long as raw material solutions are designed such that viscosity is below about 250 cP and aliquot sizes are above about 75 μl. With regard to mixing capability, total solution volume was found to have a profound affect as did the stirring mechanism.     

Fatty acids of asparagus seed oil

Summary Asparagus seed, Mary Washington variety, was found to contain 14.7% of glyceride oil having iodine value 135.1, saponification value 185.5, and unsaponifiable matter 1.46%. The oil was converted to methyl esters, and the mixed esters were separated by fractional distillation and low-temperature crystallization. The acids were identified by chemical and physical methods. The % composition of the fatty acids is estimated from the data as follows: palmitic 3, linoleic 57, oleic 27, stearic 2, eicosenoic 1.5, arachidic 0.6, undetermined 9. The oil is somewhat similar to corn oil in composition. It has at least 2% of acids of the C₂₀ series, which have not been reported previously in this plant family (Liliaceae). Presented at the meeting of the American Oil Chemists' Society, Philadelphia, Pa., October 10–12, 1955. Issued as N.R.C. No. 4426.     

Field trapping of threeEpinotia species with (Z,Z)-7,9-dodecadienyl acetate (Lepidoptera: Tortricidae)

Field survey of the geometrical isomers of 7,9-dodecadienyl alcohol, acetate, and aldehyde has resulted in attractants and inhibitors for three species of tortricid moths.Epinotia silvertoniensis and an undescribedEpinotia sp. were all attracted to (Z,Z)-7,9-dodecadienyl acetate. AnotherEpinotia sp. was attracted to (Z,Z)-7,9-dodecadienyl acetate and (Z,Z)-7,9-dodecadien-1-ol. Electroantennogram data and inhibition patterns for one of theEpinotia sp. are also reported. In addition,E. criddleana was attracted to lures containing (E)-9-dodecenyl acetate.     

Combinatorial chemistry methods for coating development: VI. Correlation of high throughput screening methods with conventional measurement techniques

Combinatorial chemistry has proven to be a valuable tool for the development of new compounds. In the pharmaceutical industry, where combinatorial chemistry began, the approach has been instrumental in the high-speed development of new drugs. Due to the overwhelming success of the combinatorial methodology in the pharmaceutical industry, it has been recently applied to materials development. We have recently developed a combinatorial factory capable of preparing and evaluating on the order of 100 organic clear coatings in a day.

One of the most challenging aspects of the creation of the combinatorial factory was the development of the high throughput screening (HTS) methods for the primary coating properties of interest such as optical clarity, abrasion resistance, adhesion, and weatherability. For each property, an entirely new method was developed that allowed for rapid measurement of these properties on very small samples. This paper describes various aspects of the development of these novel measurement systems including the correlation of the HTS methods with conventional, industry standard measurement methods.     

Catalytic Combustion of Model Carbon Particles (CPs) over Pt/β-SiC Catalyst

Platinum catalyst supported on a medium surface area -SiC was successfully used for the catalytic combustion of model carbon particles and compared to a catalyst supported on a low surface area -SiC. The -SiC-based catalyst showed no deactivation as a function of cycling tests while a strong deactivation was observed on the -SiC-based catalyst. This deactivation was attributed to the progressive encapsulation of the platinum particles by a layer of silica which built up during the combustion cycle. These results render possible the use of Pt/-SiC catalyst as a diesel carbon particle catalytic filter with continuous regeneration.     

Sex attractants for Geometrid and Noctuid moths

Male moths belonging to 17 species of Geometridae and nine species of Noctuidae were captured in traps baited with synthetic chemicals as part of a field screening program. The compounds tested were the C₁₈-C₂₂ homologs of: (1) (3Z,6Z,9Z)-triene hydrocarbons; (2) mixtures containing equal quantities of (3Z,6Z)-cis-9,10-expoxydienes, (3Z,92Z)-cis-6,7-epoxydienes, and (6Z,9Z)-cis-3,4-epoxydienes; (3) (3Z,6Z)-9S,10R-epoxydienes; (4) (3Z,6Z)-9R,10S-epoxydienes; and (5) (3Z,6Z,9Z,11E)-nonadecatetraene. Field captures and electroantennographic assays revealed a high degree of specificity in the responses of many species to the synthetic chemicals. In several species the ability of males to discriminate between the 9S,10R and 9R,10S enantiomers of the monoepoxydiene isomers was clearly shown. Synergists and inhibitors were discovered for several of the reported attractants, some of which were not previously known to have semiochemical activity. The geometrid moths captured includedEpirrhoe sperryi (Herbulot),Mesoleuca ruficillata (Guenée),Triphosa haesitata (Guenée),Metanema inatomaria (Guenée),Prochoerodes transversata (Drury),Cabera erythemaria (Guenée),Synaxis jubararia (Hulst),Dysstroma brunneata ethela (Hulst),Eulithes testata (Linnaeus),Sicya macularia (Harris),Xanthorhoe iduata (Guenée),X. abrasaria aquilonaria (Herrich-Schäffer),X. munitata (Hübner),Itame loricaria (Eversmann),Eupithecia annulata (Hulst),E. rovocastaliata (Packard) andE. satyrata dodata (Taylor). The noctuid moths captured includedBleptina caradrinalis (Guenée),Idia américalis (Guenée),I. aemula (Hübner),Rivula propinqualis (Guenée),Lomanaltes eductalis (Walker),Spargaloma sexpunctata (Grote),Caenurgina distincta (Neumuller),Euclidia cuspidea (Hübner), andZale duplicata (Bethune). Six of the nine noctuid species captured belong to three subfamilies for which sex attractants had not been reported previously. Details for the stereospecific synthesis of (3Z,6Z)-cis-9,10-epoxydienes are also reported.Issued as NRCC No. 24314.     

Can traditional fault prediction models be used for vulnerability prediction?

Finding security vulnerabilities requires a different mindset than finding general faults in software—thinking like an attacker. Therefore, security engineers looking to prioritize security inspection and testing efforts may be better served by a prediction model that indicates security vulnerabilities rather than faults. At the same time, faults and vulnerabilities have commonalities that may allow development teams to use traditional fault prediction models and metrics for vulnerability prediction. The goal of our study is to determine whether fault prediction models can be used for vulnerability prediction or if specialized vulnerability prediction models should be developed when both models are built with traditional metrics of complexity, code churn, and fault history. We have performed an empirical study on a widely-used, large open source project, the Mozilla Firefox web browser, where 21% of the source code files have faults and only 3% of the files have vulnerabilities. Both the fault prediction model and the vulnerability prediction model provide similar ability in vulnerability prediction across a wide range of classification thresholds. For example, the fault prediction model provided recall of 83% and precision of 11% at classification threshold 0.6 and the vulnerability prediction model provided recall of 83% and precision of 12% at classification threshold 0.5. Our results suggest that fault prediction models based upon traditional metrics can substitute for specialized vulnerability prediction models. However, both fault prediction and vulnerability prediction models require significant improvement to reduce false positives while providing high recall.