RESUMO
Urbanization processes in Asia are still ongoing; thus, aggregate demand is expected to increase in following years. Even though construction and demolition waste is a source for secondary building materials in industrialized countries, it is not yet an alternative construction material source in Vietnam as the urbanization process is still ongoing. Thus, there is a need for river sand and aggregates alternatives in concrete, namely manufactured sand (m-sand) from primary solid rock materials and secondary waste materials. The focus in the present study for Vietnam was on m-sand sand as alternative for river sand, and different ashes as alternatives for cement in concrete. The investigations comprised concrete lab tests according to the formulations of concrete strength class C 25/30 in accordance with DIN EN 206, followed by a lifecycle assessment study in order to identify the environmental impact of the alternatives. In total 84 samples were investigated, consisting of 3 reference samples, 18 samples with primary substitutes, 18 samples with secondary substitutes, and 45 samples with cement substitutes. This kind of holistic investigation approach comprising material alternatives and accompanying LCA was the first study for Vietnam, and even for Asia, and represents a substantial added value for future policy development in order to cope with resource scarcity. The results show that with the exception of metamorphic rocks, all m-sands meet the requirements for quality concrete. In terms of cement replacement, the mixes showed that a higher percentage of ash reduces the compressive strength. The compressive strength values of the mixes with up to 10% coal filter ash or rice husk ash were equivalent to the C25/30 standard concrete formulation. Higher ash contents up to 30% lead to the reduction of the concrete quality. The LCA study's results highlighted the better environmental footprints across environmental impact categories in the 10% substitution material in comparison to the use of primary materials. The LCA analysis results showed that cement as a component in concrete holds the highest footprint. The use of secondary waste as alternative for cement provides significant environmental advantage.
RESUMO
Patients with major depressive disorder (MDD) have repeatedly been described to exhibit both a humoral as well as a cellular pro-inflammatory state. Acute exercise, representing physical stress, can further aggravate such an immune dysbalance. In the light of recommended exercise programmes for depressed patients, we aimed to investigate the inflammatory response to exercise in patients with MDD. Blood cells counts and concentrations of the pro-inflammatory cytokines IL-1ss and IL-6 as well as the anti-inflammatory cytokine IL-10 were obtained before and after a single maximum exercise test in 15 patients suffering from MDD and 15 controls applying a stepwise exhaustion protocol. Patients showed increased white cell counts before and after exercise. While starting from different baseline levels, however, the relative increase in both humoral and cellular inflammatory parameters did not differ between groups. The results from this study suggest that physical training programmes for MDD patients do not bear a dramatically increased risk for acute pro-inflammatory exacerbations. Thus, continuous training programmes that have been shown to reduce the pro-inflammatory state in these patients can be recommended.
