Enrichment of humic material with hydroxybenzene moieties intensifies its physiological effects on the nematode Caenorhabditis elegans

Dissolved humic substances are taken up by organisms and interact on various molecular and biochemical levels. In the nematode Caenorhabditis elegans, such material can promote longevity and increase its reproductive capacity; moreover, the worms tend to stay for longer in humic-enriched environments. Here, we tested the hypothesis that the chemical enrichment of humic substances with hydroxybenzene moieties intensifies these physiological effects. Based on the leonardite humic acid HuminFeed (HF), we followed a polycondensation reaction in which this natural humic substance and a dihydroxybenzene (hydroquinone or benzoquinone) served as reaction partners. Several analytical methods showed the formation of the corresponding copolymers. The chemical modification boosted the antioxidant properties of HF both in vitro and in vivo. Humic substances enriched with hydroxybenzene moieties caused a significantly increased tolerance to thermal stress in C. elegans and extended its lifespan. Exposed nematodes showed delayed linear growth and onset of reproduction and a stronger pumping activity of the pharynx. Thus, treated nematodes act younger than they really are. In this feature the modified HF replicated the biological impact of hydroquinone-homopolymers and various plant polyphenol monomers, thereby supporting the hydroxybenzene moieties of humic substances as major effective structures for the physiological effects observed in C. elegans.     

Computational Fluid Dynamics and the Design of Sewage Storage Chambers

Recently in the UK, there has been significant interest in the design of combined sewer overflow chambers and storage tanks. This paper describes an extensive laboratory and computational fluid dynamics study into the hydraulic performance and sediment retention efficiency of tanks. The work has shown that (i) it is possible to predict the flow field which is measured in the laboratory using computational fluid dynamics, and (ii) a critical bed shear stress may be used to determine the extent of sediment deposition. Subsequently a bed shear stress model and the particle tracking routine in 'FLUENT'have been used to compare the sediment retention efficiency of eight different chamber designs. The results showed that the length to breadth ratio of the chamber was the most important parameter to influence sediment deposition, and that changes to the benching and longitudinal gradient of the tank had minimal effect.     

Die zweite Brücke über den Panamakanal – eine Schrägkabelbrücke mit 420 m Mittelöffnung und Rekordbauzeit

The second Bridge across the Panama Canal – a Cable-stayed Bridge with 420 m Main Span and a recordbraking Construction Time. The second bridge across the Panama Canal is a single plane cable-stayed bridge with a total length of 1052 m and a main span of 420 m. The 34,1 m wide bridge deck from prestressed concrete is 80 m above the water level and consists of a trapezoidal box girder and wide cantilevers. For the construction of the bridge, including the final design, two years were available only. This required – besides an uncommon effort of all parties involved – to reduce the substructures as per the tender documents substantially by a more precise soil evaluation and an optimization of the structural system.     

Die Geh‐ und Radwegbrücke Kehl – Strasbourg

The Pedestrian and Cycle Bridge Kehl – Strasbourg. The Rhine bridge between Kehl and Strasbourg is the new regional landmark and linking element of the International Gardening Show. The approach to unifying different functions and an architectural endeavour lead to a unique structural system. Two separate decks address the different situations on the river banks and, linked by a platform, form a balcony above the Rhine at midspan. The main bridge is a cable‐stayed structure with a steel pylon and a steel‐concrete composite deck. The approach bridges are continuous girders on steel columns. Both pile and flat foundations are featured in the design. The article describes the structural concept and design, outlines the erection procedure and discusses aspects of the dynamic behaviour of the bridge.     

Coping with daily events and short-term mood changes: An unexpected failure to observe effects of coping.

This study examined the relationship between coping efforts and stress-related mood changes. Men and women with high levels of work or marital stress reported stress and coping efforts approximately once an hour for 2 days using an electronic diary. Stress episodes were identified as a stress-free time followed by a stressor at the next time point. Analyses examined how appraisals and coping influenced pre- to poststress mood change and how problem appraisals were related to coping efforts. Greater mood changes were associated with appraisals of high stress and high disruptiveness. Appraisals of high control and high desirability were associated with more planning, direct action, and fewer acceptance coping efforts. Coping failed to predict any pre- to poststressor mood changes. Possible explanations for the overall failure of coping to predict momentary mood changes are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of test set minimization on fault detection effectiveness

Given a test set T to test a program P, there are at least two attributes of T that determine its fault detection effectiveness. One attribute is the size of T measured as the number of test cases in T. Another attribute is the code coverage measured when P is executed on all elements of T. The fault detection effectiveness of T is the ratio of the number of faults guaranteed to result in program failure when P is executed on T to the total number of faults present in P. An empirical study was conducted to determine the relative importance of the size and coverage attributes in affecting the fault detection effectiveness of a randomly selected test set for some program P. Results from this study indicate that as the size of a test set is reduced, while the code coverage is kept constant, there is little or no reduction in the fault detection effectiveness of the new test set so generated. For the study reported, of the two attributes mentioned above, the code coverage attribute of a test set is more important than its size attribute. © 1998 John Wiley & Sons, Ltd.     

Mechanical and thermal properties of polypropylene/montmorillonite nanocomposites using stearic acid as both an interface and a clay surface modifier

The effects of stearic acid treatment on the crystallization, morphology, thermal, and mechanical properties of polypropylene (PP)/montmorillonite (Mm) nanocomposites were investigated. Stearic acid was used as a new surface modifier for Mm, and also small amounts of this acid were used as a new interface modifier. Nanocomposites containing 1.5, 2.5, 5, and 10% in weight of the unmodified and modified Mm were prepared by melt blending. The tensile and impact properties of nanocomposites were evaluated. Wide‐angle X‐ray diffraction was used to study both the generated PP β crystals and the dispersion state of the nanocomposites. Differential scanning calorimeter was used to detect the melting and crystallization behavior of the samples. The toughness of some nanocomposites was higher than the pure PP. β phase of PP was observed with the addition of Mm. Stearic acid favored the dispersion of the nanocomposites when used as interface modifier. Nanocomposites with better dispersion exhibited crystallization temperatures similar to pure PP. POLYM. COMPOS., 35:1–9, 2014. © 2013 Society of Plastics Engineers