Configuration in smart service systems: A practice‐based inquiry

In this paper, we develop a new perspective on configuration processes inherent to smart service systems that brings human actors to the theoretical foreground, is informed by practice theory, and is grounded in an intervention study of smart locating systems used in home care of persons with dementia. Maintaining control of the location of persons with dementia is a major source of caregiver burden, and assistive technologies such as smart locating systems hold the promise of enhancing quality of life and reducing caregiver burden. Drawing from research on smart service systems, organizational configuration research, and practice theory, we articulate a conceptual model of configuring in practice to explain how practice elements and the capabilities of smart technologies become mutually configured. Our analysis of study participants' experiences with the locating systems identified three distinctive configurations, characterized as enhanced smartness, degraded smartness, and fragile smartness, which developed through configuring processes. The configuring in practice model we develop here helps explain why unexpected and anticipated configurations develop and thus the conditions that facilitate or inhibit value cocreation in smart service systems.     

Light‐Driven Proton Transfer for Cyclic and Temporal Switching of Enzymatic Nanoreactors

Temporal activation of biological processes by visible light and subsequent return to an inactive state in the absence of light is an essential characteristic of photoreceptor cells. Inspired by these phenomena, light‐responsive materials are very attractive due to the high spatiotemporal control of light irradiation, with light being able to precisely orchestrate processes repeatedly over many cycles. Herein, it is reported that light‐driven proton transfer triggered by a merocyanine‐based photoacid can be used to modulate the permeability of pH‐responsive polymersomes through cyclic, temporally controlled protonation and deprotonation of the polymersome membrane. The membranes can undergo repeated light‐driven swelling–contraction cycles without losing functional effectiveness. When applied to enzyme loaded‐nanoreactors, this membrane responsiveness is used for the reversible control of enzymatic reactions. This combination of the merocyanine‐based photoacid and pH‐switchable nanoreactors results in rapidly responding and versatile supramolecular systems successfully used to switch enzymatic reactions ON and OFF on demand.     

An experimental investigation on the fatigue crack growth behaviour of AISI/SAE 1045 under load sequences containing underloads

The estimation of load interaction effects is essential for residual lifetime calculations of components with cracks. Whereas overloads are widely investigated, there is still no consensus about the effects and mechanisms of underloads. For this reason, load sequences containing underloads are experimentally examined within this paper. Because K_max and R are not appropriate for describing the cyclic crack tip loading at tension/compression loading, the σ_tip concept is used to quantify the crack driving force at compressive loads. Among others, the tests also include load sequences that have not been reported in the literature yet like underloads that are applied at a certain distance after an overload. The influence of underloads on crack arrest is also investigated. The experimental tests are performed with the tool steel AISI/SAE 1045.     

Ausmaß und Dynamik der Sohlerosion der Donau östlich von Wien – flussmorphologische und wasserwirtschaftliche Aspekte

The Danube east of Vienna was originally an untamed, widely branching river with an approximately stable bed elevation. Regulation in the second half of the 19th century changed its morphology fundamentally—initially through upstream regulation and the consequent bedload deposit resulting in heavy aggradation—and subsequently left the bed elevation and water level almost the same until around the 1940s. Only in the second half of the 20th century did the bed elevation and low and mean water levels decrease significantly, and this trend—amplified by the power plant extension—continues today, despite constant bedload dumps to ensure the tailwater supply for the power plant at Vienna Freudenau. Further east from the Austrian-Slovak stretch of border, congestion due to the Gab?íkovo power plant becomes apparent: most of the bedload is again deposited here. This study investigates these processes using hydrographic observations in their spatial and temporal context, and, based on actual bed elevation measurements, creates a bedload balance and compares it with the results of previous studies. Bed erosion in the Danube floodplains and the local national park has far-reaching consequences, especially through siltation and scrub encroachment in the river’s branches, which are further amplified by flat, fine sediment deposits in the foothills and the formation of embankments. In the long term, flood and other water management objectives will also be adversely affected.     

Analysis of amino acid isotopomers using FT-ICR MS

Fluxes through known metabolic pathways and the presence of novel metabolic reactions are often determined by feeding isotopically labeled substrate to an organism and then determining the isotopomer distribution in amino acids in proteins. However, commonly used techniques to measure the isotopomer distributions require derivatization prior to analysis (gas chromatography/mass spectrometry (GC/MS)) or large sample sizes (nuclear magnetic resonance (NMR) spectroscopy). Here, we demonstrate the use of Fourier transform-ion cyclotron resonance mass spectrometry with direct infusion via electrospray ionization to rapidly measure the amino acid isotopomer distribution in a biomass hydrolysate of the soil bacterium Desulfovibrio vulgaris Hildenborough. By applying high front-end resolution for the precursor ion selection followed by sustained off-resonance irradiation collision-induced dissociation, it was possible to determine exactly and unambiguously the specific locations of the labeled atoms in the amino acids, which usually requires a combination of 2-D 13C NMR spectroscopy and GC/MS. This method should be generally applicable to all biomass samples and will allow more accurate determination of metabolic fluxes with less work and less sample.