Prediction of lithogenic character of human bile by a quaternary system

The lithogenic character of human gallbladder bile was investigated by a mathematical model on the basis of a clinical data set. Each bile was described by means of the quaternary system bile salts--phospholipids--free fatty acids--cholesterol. Reporting a set of bile samples on the tetrahedron of concentrations, a clear separation emerged between the control bile, the bile from patients with gallstones, and the bile of subjects with gallbladder dyskinesia. This group was characterized by a largely increased content of free fatty acids.     

A comparison of antioxidant properties between artisan‐made and factory‐produced chocolate

The antioxidant capacities and the total phenolic content in cocoa liquor directly manufactured chocolate from an artisan manufacturer were measured using different in vitro methods (BR, TEAC, and Folin–Ciocalteu Reagent). These parameters were then compared with those of a chocolate made by a leading manufacturing company producing chocolate and cocoa‐containing products. A statistical analysis of the collected data showed that the antioxidant properties of the artisan‐made chocolate are significantly better than those of the factory‐produced one. These results were ascribed to the fact that all the bioactive components in the cocoa beans are better preserved in the artisan‐made chocolate.     

Strain-life fatigue predictions for sintered steels with nonzero mean stress

Several approximate models have been utilized for fatigue life prediction. Some of these models are available for mean stress (or strain) correction on fatigue life, when nonzero mean stress (or strain) is applied. In this paper, the most commonly used empirical strain-life models for fatigue life predictions, for materials subjected to variable amplitude loads, are described. Experimental results of fatigue tests, where the specimens of sintered steels were subjected to partial random loads, are presented and compared with those results obtained theoretically by the models. The utilization of the various models and their influence on results are discussed.     

A DNA-Micropatterned Surface for Propagating Biomolecular Signals by Positional on-off Assembly of Catalytic Nanocompartments

Signal transduction is pivotal for the transfer of information between and within living cells. The composition and spatial organization of specified compartments are key to propagating soluble signals. Here, a high-throughput platform mimicking multistep signal transduction which is based on a geometrically defined array of immobilized catalytic nanocompartments (CNCs) that consist of distinct polymeric nanoassemblies encapsulating enzymes and DNA or enzymes alone is presented. The dual role of single entities or tandem CNCs in providing confined but communicating spaces for complex metabolic reactions and in protecting encapsulated compounds from denaturation is explored. To support a controlled spatial organization of CNCs, CNCs are patterned by means of DNA hybridization to a microprinted glass surface. Specifically, CNC-functionalized DNA microarrays are produced where individual reaction compartments are kept in close proximity by a distinct geometrical arrangement to promote effective communication. Besides a remarkable versatility and robustness, the most prominent feature of this platform is the reversibility of DNA-mediated CNC-anchoring which renders it reusable. Micropatterns of polymer-based nanocompartment assemblies offer an ideal scaffold for the development of the next generation responsive and communicative soft-matter analytical devices for applications in catalysis and medicine.     

IgA antibodies to tissue transglutaminase: An effective diagnostic test for celiac disease

OBJECTIVE: Tissue transglutaminase (tTG) is the main autoantigen recognized by endomysial antibodies. The aim of this study was to assess sensitivity, specificity, and predictive value of IgA and IgG antibodies to tTG in the diagnosis of celiac disease compared with endomysial antibodies. STUDY DESIGN: We established enzyme-linked immunosorbent assay procedures to measure IgA and IgG antibodies to tTG in sera from 48 untreated and 33 treated patients with celiac disease and from 63 patients with gastrointestinal disease who were in a control group. Sera from 10 patients with celiac disease were examined at various times after gluten was reintroduced into the patients' diet. RESULTS: Both IgA and IgG to tTG were significantly (P <.001) higher in serum of untreated patients with celiac disease versus those in the control group; IgA but not IgG was significantly (P <.001) higher in untreated versus treated patients with celiac disease. IgA and IgG antitissue tTG had a diagnostic sensitivity, specificity, and positive predictive value of 92% and 21%, 98% and 97%, and 98% and 83%, respectively. The concordance rate of IgA anti-tTG with IgA antiendomysial antibodies was 95%. In 5 of the 10 patients undergoing gluten challenge, IgA antiendomysium antibodies were detected earlier than IgA anti-tTG antibodies. CONCLUSIONS: tTG-based enzyme-linked immunosorbent assay is an effective diagnostic test, although immunofluorescent-based assays are more sensitive, particularly during gluten challenge.     

New Approach to Water Distribution Network Calibration

A new approach is proposed for calibrating hydraulic network models. This procedure uses a nonlinear optimization algorithm along with a standard, off-the-shelf, network solver. Pipe roughness is adjusted until simulation results agree with the values observed in the field. To achieve realistic calibrated roughness values, the objective is to minimize the sum of the squares of the differences between the calibrated and initial pipe roughness estimates, under a set of constraints determined from a sensitivity matrix. The algorithm is applied to a sample network, and the resulting calibrated network is tested under different loading conditions.