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1.
For safety and security reasons
Alexander Zuepke, Kai Beckmann, Andreas Zoor, Reinhold Kroeger, 2016, original scientific article

Abstract: The current development trend of Internet of Things (IoT) aims for a tighter integration of mobile and stationary devices via various networks. This includes communication of vehicles to roadside infrastructure (V2I), as well as intelligent sensors / actors in Logistics and smart home environments. Compared to isolated traditional embedded systems, the exposure to open networks increases the attack surface, and errors in the networking components could compromise the safety and security of the embedded application or the whole network. But often current system architectures for mass-market IoT devices lack the required isolation concepts. Using a partitioning microkernel and enforcing the use of a microcontroller’s memory protection unit (MPU) facilities, we compare different isolation concepts for a publish/subscribe middleware implementing OMG’s Data Distribution Service (DDS) standard and we evaluate our results on an STM32F4 microcontroller. The results of this case study show moderate costs for increased memory usage and additional context switches.
Keywords: component-isolation, microkernel, partitioning, IoT
Published: 17.11.2017; Views: 450; Downloads: 116
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2.
Financial aspects of a seismic base isolation system for a steel high-rack structure
Vojko Kilar, Simon Petrovčič, Simon Šilih, David Koren, 2013, original scientific article

Abstract: The paper deals with the effects and costs of implementing a base isolation system for the mitigation of the seismic risk of an existing steel rack structure. Different realistic distributions of the payload mass and occupancy levels, which form different plan asymmetric variants, have been analysed. The results obtained by the pushover analysis (N2 method) are presented as top floor envelopes and as plastic hinge damage patterns. In the presented cost study, the cost of the implementation of the proposed base isolation system is compared with the estimated costs of structural repairs to the damaged structural members of the superstructure, as well as with estimated expenses of the downtime period. The results have shown that base isolation is, in general, not economically feasible for lower ground motion intensities, whereas it could be of great benefit in the case of moderate and high intensities, especially if the downtime period is taken into account.
Keywords: rack structures, seismic behaviour, base isolation, cost efficiency, mass eccentricity, pushover analysis
Published: 07.08.2017; Views: 487; Downloads: 73
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3.
Isolation and characterization of human articular chondrocytes from surgical waste after total knee arthroplasty (TKA)
Jakob Naranđa, Lidija Gradišnik, Mario Gorenjak, Matjaž Vogrin, Uroš Maver, 2017, original scientific article

Abstract: BACKGROUND: Cartilage tissue engineering is a fast-evolving field of biomedical engineering, in which the chondrocytes represent the most commonly used cell type. Since research in tissue engineering always consumes a lot of cells, simple and cheap isolation methods could form a powerful basis to boost such studies and enable their faster progress to the clinics. Isolated chondrocytes can be used for autologous chondrocyte implantation in cartilage repair, and are the base for valuable models to investigate cartilage phenotype preservation, as well as enable studies of molecular features, nature and scales of cellular responses to alterations in the cartilage tissue. METHODS: Isolation and consequent cultivation of primary human adult articular chondrocytes from the surgical waste obtained during total knee arthroplasty (TKA) was performed. To evaluate the chondrogenic potential of the isolated cells, gene expression of collagen type 2 (COL2), collagen 1 (COL1) and aggrecan (ACAN) was evaluated. Immunocytochemical staining of all mentioned proteins was performed to evaluate chondrocyte specific production. RESULTS: Cartilage specific gene expression of COL2 and ACAN has been shown that the proposed protocol leads to isolation of cells with a high chondrogenic potential, possibly even specific phenotype preservation up to the second passage. COL1 expression has confirmed the tendency of the isolated cells dedifferentiation into a fibroblast-like phenotype already in the second passage, which confirms previous findings that higher passages should be used with care in cartilage tissue engineering. To evaluate the effectiveness of our approach, immunocytochemical staining of the evaluated chondrocyte specific products was performed as well. DISCUSSION: In this study, we developed a protocol for isolation and consequent cultivation of primary human adult articular chondrocytes with the desired phenotype from the surgical waste obtained during TKA. TKA is a common and very frequently performed orthopaedic surgery during which both femoral condyles are removed. The latter present the ideal source for a simple and relatively cheap isolation of chondrocytes as was confirmed in our study.
Keywords: aggrecan, collagen 2, gene expression, human articular chondrocytes, isolation protocol, phenotype preservation, TKA, total knee arthroplasty
Published: 02.08.2017; Views: 817; Downloads: 425
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4.
Social isolation during puberty affects female sexual behavior in mice
Jasmina Kerčmar, Stuart Tobet, Gregor Majdič, 2014, original scientific article

Abstract: Exposure to stress during puberty can lead to long-term behavioral alterations in adult rodents coincident with sex steroid hormone-dependent brain remodeling and reorganization. Social isolation is a stress for social animals like mice, but little is known about the effects of such stress during adolescence on later reproductive behaviors. The present study examined sexual behavior of ovariectomized, estradiol and progesterone primed female mice that were individually housed from 25 days of age until testing at approximately 95 days, or individually housed from day 25 until day 60 (during puberty), followed by housing in social groups. Mice in these isolated groups were compared to females that were group housed throughout the experiment. Receptive sexual behaviors of females and behaviors of stimulus males were recorded. Females housed in social groups displayed greater levels of receptive behaviors in comparison to both socially isolated groups. Namely, social females had higher lordosis quotients (LQs) and more often displayed stronger lordosis postures in comparison to isolated females. No differences between female groups were observed in stimulus male sexual behavior suggesting that female “attractiveness” was not affected by their social isolation. Females housed in social groups had fewer cells containing immunoreactive estrogen receptor (ER) α in the anteroventral periventricular nucleus (AVPV) and in the ventromedial nucleus of the hypothalamus (VMH) than both isolated groups. These results suggest that isolation during adolescence affects female sexual behavior and re-socialization for 1 month in adulthood is insufficient to rescue lordosis behavior from the effects of social isolation during the pubertal period.
Keywords: mice, social isolation, female sexual behavior, estrogen receptor α, puberty, adolescence
Published: 10.07.2017; Views: 729; Downloads: 346
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5.
Highly divergent Clostridium difficile strains isolated from the environment
Sandra Janežič, Mojca Potočnik, Valerija Tkalec, Maja Rupnik, 2016, original scientific article

Abstract: Clostridium difficile is one of the most important human and animal pathogens. However, the bacterium is ubiquitous and can be isolated from various sources. Here we report the prevalence and characterization of C. difficile in less studied environmental samples, puddle water (n = 104) and soil (n = 79). C. difficile was detected in 14.4% of puddle water and in 36.7% of soil samples. Environmental strains displayed antimicrobial resistance patterns comparable to already published data of human and animal isolates. A total of 480 isolates were grouped into 34 different PCR ribotypes. More than half of these (52.9%; 18 of 34) were already described in humans or animals. However, 14 PCR ribotypes were new in our PCR ribotype library and all but one were non-toxigenic. The multilocus sequence analysis of these new PCR ribotypes revealed that non-toxigenic environmental isolates are phylogenetically distinct and belong to three highly divergent clades, two of which have not been described before. Our data suggest that environment is a potential reservoir of genetically diverse population of C. difficile.
Keywords: clostridium difficile, environment, isolation
Published: 19.06.2017; Views: 691; Downloads: 301
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6.
Isolation of chlorophylls from stinging nettle (Urtica dioica L.)
Maša Hojnik Niderl, Mojca Škerget, Željko Knez, 2007, original scientific article

Abstract: This study was aimed to assess the feasibility of extracting chlorophylls fromstinging nettle (Urtica dioica L.) by solvent extraction. In preliminary, the investigation concerned three parts of raw material (leaves, stalk and whole plant), different preservation techniques (blanching and drying) and different storage temperatures of preserved material ( |20 C for blanched and 4 C for dried sample). Extracts were analysed for chlorophyll A and chlorophyll B, respectively, by means of HPLC method. Afterwards, optimizationof single-step conventional extraction was carried out by examining the influence of the following process parameters on the extraction yield and isolation efficiency of chlorophylls: type of organic solvent, content of water in ethanol/water mixtures, ratio solvent/material, temperature, time of extraction and pH of the extraction mixture. Furthermore,to improve the yield and/or the selectivity of the extraction, multi-step conventional extraction experiments as well as other solid ]liquid extraction techniques (soxhlet and ultra-sound assisted) were performed and compared. c 2007 Elsevier B.V. All rights reserved.
Keywords: chemical processing, extraction, nettle, isolation of chlorophyll, chlorophyll content, solvent extraction
Published: 31.05.2012; Views: 2009; Downloads: 95
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