Technical note: Rapid field test for the quantification of vitamin E, β-carotene,and vitamin A in whole blood and plasma of dairy cattle

Fast and easy tests for quantifying fat-soluble vitamins such as vitamin E and vitamin A, as well as β-carotene, in whole blood without a need to preprocess blood samples could facilitate assessment of the vitamin status of dairy cattle. The objective of this study was to validate a field-portable fluorometer/spectrophotometer assay for the rapid quantification of these vitamins in whole blood and plasma of dairy cows and calves. We measured the concentrations of vitamin E and β-carotene in whole blood and plasma from 28 dairy cows and 11 calves using the iCheck test (BioAnalyt GmbH, Teltow, Germany) and compared the results with the current analytical standard (HPLC) in 2 independent laboratories, one at the University of Potsdam (Germany) and at one at DSM Nutritional Products Ltd. (Kaiseraugst, Switzerland). For vitamin A, the HPLC measurements were done only in the laboratory in Germany. The whole-blood concentrations of vitamin E as determined by iCheck (blood-hematocrit-corrected) ranged from 1.82 to 4.99 mg/L in dairy cows and 0.34 to 3.40 mg/L in calves. These findings were moderately correlated (R² = 0.66) with the values assessed by HPLC in dairy cattle (cows + calves). When calves were excluded, the correlation was higher (R² = 0.961). The β-carotene and vitamin A values obtained by the reference method HPLC were highly correlated with the iCheck methods in whole blood (R² = 0.99 and 0.88, respectively). In plasma, we observed strong correlations between the concentrations assessed by iCheck and those of HPLC for vitamin E (R² = 0.97), β-carotene (R² = 0.98), and vitamin A (R² = 0.92) in dairy cattle (cows + calves). For vitamin E, β-carotene, and vitamin A, we compared the relationship between the differences obtained by the iCheck assay and the HPLC measurements, as well as the magnitude of measurements, using Bland–Altman plots to test for systematic bias. For all 3 vitamins, the differences values were not outside the 95% acceptability limits; we found no systematic error between the 2 methods for all 3 analytes.     

Abductive Grounded Theory: a worked example of a study in construction management

Grounded Theory, now more than 50 years old, is a qualitative research approach widely employed in the social and human science studies to develop theories with a high degree of conceptuality. For construction management research, given the nature of this applied sub-discipline of management, a paradigmatic shift in Grounded Theory is needed, from classical positivism to pragmatism. Abductive Grounded Theory is posited as the way to achieve this shift in research methodology. The proposition is explored through a worked example, using Early Contractor Involvement research as a case study to demonstrate the research process. The data analysis process of open coding, axial coding and selective coding is described, together with the process of matching complementary prospect theory to explain the interdependencies between theoretical categories. The issues of validity and reliability are addressed. Of particular importance is the faithfulness to the original analytical coding process and then abduction of existing theories from salient literature to explain the relationships amongst emergent concepts. The findings show that, while the development of the research question is initially influenced by the review of literature, there is no deliberate effort to direct or force the collected information towards any set of pre-defined concepts. The study shows promising potential for using Abductive Grounded Theory to develop conceptual and instrumental theories in construction management research.     

Age-Dependent Control of Collagen-Dependent Platelet Responses by Thrombospondin-1—Comparative Analysis of Platelets from Neonates,Children, Adolescents,and Adults

Platelet function is developmentally regulated. Healthy neonates do not spontaneously bleed, but their platelets are hypo-reactive to several agonists. The mechanisms underlying immature platelet function in neonates are incompletely understood. This critical issue remains challenging for the establishment of age-specific reference ranges. In this study, we evaluated platelet reactivity of five pediatric age categories, ranging from healthy full-term neonates up to adolescents (11–18 years) in comparison to healthy adults (>18 years) by flow cytometry. We confirmed that platelet hypo-reactivity detected by fibrinogen binding, P-selectin, and CD63 surface expression was most pronounced in neonates compared to other pediatric age groups. However, maturation of platelet responsiveness varied with age, agonist, and activation marker. In contrast to TRAP and ADP, collagen-induced platelet activation was nearly absent in neonates. Granule secretion markedly remained impaired at least up to 10 years of age compared to adults. We show for the first time that neonatal platelets are deficient in thrombospondin-1, and exogenous platelet-derived thrombospondin-1 allows platelet responsiveness to collagen. Platelets from all pediatric age groups normally responded to the C-terminal thrombospondin-1 peptide RFYVVMWK. Thus, thrombospondin-1 deficiency of neonatal platelets might contribute to the relatively impaired response to collagen, and platelet-derived thrombospondin-1 may control distinct collagen-induced platelet responses.     

CLA TAG rich in cis‐9,trans‐11‐CLA is stable beyond 2 years of proper storage

We analyzed a triacylgylcerol esterified CLA preparation characteristically rich in c9,t11‐CLA and free of t10,c12‐CLA three times within a period of 2${1 \over 2}$ years by GC and silver ion‐HPLC. For the first time, we present data on the long‐term stability of this preparation with regard to the fatty acid profile and the isomeric composition of CLA under certain storage conditions, providing useful information for the planning of long‐term trials.     

Fragment‐Based Lead Discovery: Screening and Optimizing Fragments for Thermolysin Inhibition

Fragment‐based drug discovery has gained a foothold in today's lead identification processes. We present the application of in silico fragment‐based screening for the discovery of novel lead compounds for the metalloendoproteinase thermolysin. We have chosen thermolysin to validate our screening approach as it is a well‐studied enzyme and serves as a model system for other proteases. A protein‐targeted virtual library was designed and screening was carried out using the program AutoDock. Two fragment hits could be identified. For one of them, the crystal structure in complex with thermolysin is presented. This compound was selected for structure‐based optimization of binding affinity and improvement of ligand efficiency, while concomitantly keeping the fragment‐like properties of the initial hit. Redesigning the zinc coordination group revealed a novel class of fragments possessing K_i values as low as 128 μM , thus they provide a good starting point for further hit evolution in a tailored lead design.     

Influence of acetate and formate-based deicers on ASR in airfield concrete pavements

In the past few years, the issue of external alkalis and their influence on ASR in concrete has become more important since several concrete airfield pavements have shown ASR-distress related to the use of alkali-containing airfield deicers based on acetates and formates.Experiments with model pore solutions and cement pastes as well as speciation calculations and ASR performance tests were conducted to investigate possible mechanisms. The obtained results indicate that the solubility of portlandite is increased in the presence of acetate-based and formate-based deicers due to the formation of Ca-acetate and Ca-formate complexes. The additional release of OH⁻ ions from portlandite and the supply of alkalis can initiate and highly accelerate ASR in concretes with reactive aggregates. There is also evidence for a reaction of ettringite with such airfield deicers.     

Olefin cyclopropanations via sequential atom transfer radical addition-dechlorination reactions

In organic synthesis, cyclopropanation reactions are often performed with Simmons-Smith-type reagents or by transition metal catalyzed reactions of olefins with diazo compounds. A novel method for the synthesis of substituted cyclopropanes is described that is based on a two-step reaction sequence. Olefins are reacted with 1,1'-dichlorides in a Ru-catalyzed atom transfer radical addition (ATRA) process and the resulting 1,3-dichlorides are directly converted into cyclopropanes by reductive coupling with magnesium. This one-pot procedure is applicable to a variety of substrates and can be performed in an inter- or intramolecular fashion.     

Quasi-static cyclic tests and plastic hinge analysis of RC structural walls

This paper presents the results of quasi-static cyclic tests on six reinforced concrete (RC) walls performed at the ETH Zurich. These large-scale tests investigate the effect of different vertical reinforcement contents and different reinforcement ductility properties typical for Central Europe on the deformation behaviour of slender RC walls. The test data documenting the global and local behaviour of the test units is available online and can therefore serve as a reference point for the research community. The experimental results show the importance of the reinforcement content and the ductility properties of both the boundary and web reinforcement for the deformation behaviour of the walls. By comparing base curvatures derived from experimental data with curvatures obtained from section analysis, strain limits characterising different limit states in plastic hinge analysis are suggested. These strain limits can be used in the performance-based design and assessment of RC structural walls.     

Dispersion analysis of spreadable processed cheese with low content of emulsifying salts by photocentrifugation

Photocentrifugation at 1200  g and 60 °C was used to monitor emulsion stability of spreadable processed cheese (PC) with a low content (0.7 and 1.0 g 100 g^?1) of typical emulsifying salts (ES) after different manufacturing conditions. This method of dispersion analysis has been used more frequently for nonfood materials rather than for foodstuffs. The PC contained 36.5 g 100 g^?1 dry matter, 40 g 100 g^?1 fat in dry matter and was manufactured in a laboratory cooker at 82 or 92 °C and 1000–3000 rpm cutter speed for 5–19 min. Insufficient fat emulsification and a heterogeneous casein matrix of a PC with 0.7% was well illustrated by photocentrifugation. At 1 g 100 g^?1 ES and 3000 rpm cutter speed, the effect of manufacturing time on the behaviour of the colloidal dispersion was demonstrated by the different evolutions of the corresponding transmission profiles. Sedimentation velocities were measured at a level of 20% transmission. These results showed that dispersion analysis of spreadable PC by photocentrifugation at 60 °C is a sensitive method and applicable as a new approach for characterisation of emulsion stability resulting from physicochemical changes during manufacture.