Spatial and temporal changes in Actinobacterial dominance in experimental artificial groundwater recharge

Artificial groundwater recharge (AGR) is used in the drinking water industry to supplement groundwater resources and to minimise the use of chemicals in water treatment. This study analysed the spatial and temporal changes of microbial communities in AGR using two test systems: a nutrient-amended fluidized-bed reactor (FBR) and a sand column. Structural changes in the feed lake water (Lake Roine), FBR, and sand column bacterial communities were determined by denaturing gradient gel electrophoresis (DGGE) and the length heterogeneity analysis of amplified 16S rRNA genes (LH-PCR). Two clone libraries were created to link the LH-PCR results to the dominant bacterial groups. The lake water bacterial community was relatively stable, with three bands dominating in all LH-PCR products. The most dominant fragment accounted for up to 72% and was derived from Actinobacteria. Based on the clone libraries and LH-PCR data, Actinobacteria also dominated in the unattached bacterial community of the FBR, whereas several Proteobacterial groups were more abundant on the FBR carrier particles. In the stabilised AGR system a major change in the community structure of the lake water bacteria took place during passage within the first 0.6 m in the sand column as the community composition shifted from Actinobacteria-dominated populations to a diverse, mainly Proteobacterial communities. Concurrently, most of the dissolved organic carbon (DOC) was removed at this stage. In summary, the study showed that the make-up of microbial communities in experimental AGR systems responded to changes in their environment. LH-PCR showed potential as a method to determine microbial community dynamics in long-term studies at real-scale AGR sites. This is the first step to provide data on microbial community dynamics in AGR for drinking water production.     

Degradative and mechanical properties of a novel resorbable plating system during a 3-year follow-up in vivo and in vitro

We tested the tissue reactions and mechanical strength of a novel biodegradable craniomaxillofacial plating system, Inion CPS™, in the course of degradation. Plates and screws composed of l-lactide, d-lactide and trimethylene carbonate were implanted to the mandible and dorsal subcutis of 12 sheep. The animals were sacrificed at 6–156 weeks. Histological evaluation was done using paraffin and methylmetacrylate techniques. Degradative and mechanical properties during the follow-up were measured both of in vivo and in vitro implants. In light microscopy, the in vivo implant material began to fragment at 52 weeks and could not be detected at 104 weeks. No significant foreign body reactions were seen in the mandibles. The dorsal subcutis disclosed mild reactions, which were, however, not of clinical significance. The implants in vitro maintained their entire mass for 26 weeks and lost 63–80% of the mass by week 104. The inherent viscosity of the implants in vitro and in vivo diminished uniformly. The screws retained their shear strength for 12–16 weeks. The plates maintained their tensile strength for at least 6 weeks. The maximum capacity of the plates in 3-point bending tests diminished gradually by 87% in 26 weeks. In conclusion, the plates and screws examined maintain adequate strength for the healing period of a bone fracture or osteotomy, producing no harmful foreign body reactions. Dr Nieminen is a consultant for Inion Ltd., while the other co-authors do not have any conflicts of interest. Inion Ltd. has financed the costs related to the study sheep, including their housing.     

Hybrid radiative-transfer-diffusion model for optical tomography

A hybrid radiative-transfer-diffusion model for optical tomography is proposed. The light propagation is modeled with the radiative-transfer equation in the vicinity of the laser sources, and the diffusion approximation is used elsewhere in the domain. The solution of the radiative-transfer equation is used to construct a Dirichlet boundary condition for the diffusion approximation on a fictitious interface within the object. This boundary condition constitutes an approximative distributed source model for the diffusion approximation in the remaining area. The results from the proposed approach are compared with finite-element solutions of the radiative-transfer equation and the diffusion approximation and Monte Carlo simulation. The results show that the method improves the accuracy of the forward model compared with the conventional diffusion model.     

Development and validation of a novel portable slip simulator

The objective was to develop, construct and validate a portable device suitable for measurements of pedestrian slip resistance in situ. The developed device proved to be precise enough and easy to use. The dynamic coefficient of friction (DCOF) values measured by it showed strong correlation (r> or = 0.990, p < 0.001) with the values measured by the force platform used as a reference. In addition, the measured DCOF values were in good consistency with those obtained when using the older laboratory device of the Institute, the slip simulator. Based on the use of the new, developed device it can be concluded that accurate friction measurements with actual footwear can be performed even with a moderate-sized but portable device. The developed slipmeter will be used to measure slipperiness of various walking surface conditions, e.g. at different work places and in walkways, in the near future.     

Porous Silicon Nanoparticle Delivery of Tandem Peptide Anti‐Infectives for the Treatment of Pseudomonas aeruginosa Lung Infections

There is an urgent need for new materials to treat bacterial infections. In order to improve antibacterial delivery, an anti‐infective nanomaterial is developed that utilizes two strategies for localization: i) a biodegradable nanoparticle carrier to localize therapeutics within the tissue, and ii) a novel tandem peptide cargo to localize payload to bacterial membranes. First, a library of antibacterial peptides is screened that combines a membrane‐localizing peptide with a toxic peptide cargo and discovers a tandem peptide that displays synergy between the two domains and is able to kill Pseudomonas aeruginosa at sub‐micromolar concentrations. To apply this material to the lung, the tandem peptide is loaded into porous silicon nanoparticles (pSiNPs). Charged peptide payloads are loaded into the pores of the pSiNP at ≈30% mass loading and ≈90% loading efficiency using phosphonate surface chemistry. When delivered to the lungs of mice, this anti‐infective nanomaterial exhibits improved safety profiles over free peptides. Moreover, treatment of a lung infection of P. aeruginosa results in a large reduction in bacterial numbers and markedly improves survival compared to untreated mice. Collectively, this study presents the selection of a bifunctional peptide‐based anti‐infective agent and its delivery via biodegradable nanoparticles for application to an animal model of lung infection.     

On accepting smart environments at user and societal levels

This paper studies beliefs which predict acceptance of smart environments at the user level and the preconditions for acceptance at the societal level. The authors use a thorough literature survey and eight in-depth expert interviews based on four scenarios (home, conference, mall, and gym). As the results indicate, the crucial beliefs for acceptance turn out to be usefulness, ease of use, trust, and social influence at the user level. At the societal level, the preconditions are cultural, economic, and legal. The in-depth interviews confirm some of the results previously reported in the literature including the importance of usefulness, ease of use, and trust for user acceptance. In addition to previous results, social influence as a belief is considered. The external variables affecting beliefs are divided into two categories, namely individual differences and circumstantial differences. Individual differences include variables (age, socio-economic status, experience) already known in the literature, also considering health. Circumstantial differences include audience and place. Place can be public, semi-public, or private and considered from the viewpoints of location (size, pathways) and degree of familiarity. Audience was considered from the amount and role of people at presence (alone, with friends, with strangers). To the authors’ knowledge, these circumstantial differences have not been discussed in the user acceptance literature before.     

The effects of gamma-irradiation on some pure aroma compounds of spices

Summary Chemical changes due to gamma-irradiation were investigated in 11 pure aroma compounds typically found in spices. Samples were irradiated with doses of 0, 10, and 50 kGy. The irradiation source was⁶⁰Co. Irradiated samples and unirradiated controls were analyzed by gas chromatography alone and coupled with mass spectrometry. Significant changes due to the irradiation occurred only in (±)-linalool and-terpineol, which are typical components of, for example, coriander and bay leaf. Their total amounts decreased by about 4–13% and some minor peaks increased as a result of irradiation. However, different results may be obtained when the spices themselves are irradiated.

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Auswirkungen der -Strahlung auf einige Gewürz-Aromastoffe

Zusammenfassung An elf gewürztypischen Aromastoffen wurden die von der-Strahlung verursachten Veränderungen untersucht. Die Proben wurden unter Verwendung von⁶⁰Co als Strahlungsquelle mit Dosen von 0, 10 und 50 kGy bestrahlt. Die bestrahlten und unbestrahlten Proben wurden gaschromatographisch (GC) und GC-massenspektrometrisch untersucht. Erhebliche Veränderungen zeigten sich nur beim (±)-Linalool und beim-Terpineol, die zum Beispiel für die ätherischen Öle von Koriander und Lorbeerblatt typisch sind. Die Peaks dieser Aromastoffe reduzierten sich um 4–13%, und dem entsprechend waren einige kleinere Peaks zu beobachten. Es kann dennoch zu unterschiedlichen Resultaten kommen, wenn Gewürze bestrahlt werden.