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In order to increase public interest and awareness in polar areas and to contribute to rising a new generation of polar scientist, Estonian Polar Club organised in 2017 polar knowledge contest and following expedition to North Scandinavia for high school students. The I stage of contest was Internet-based. During 3 days the attendants had to answer to 40 questions on Arctic and Antarctic environment and its protection, plant and animal life, human acivities and research history, incl. contributions from Estonians. There was 258 attendants aged 15-19 from 40 schools all over Estonia. The best 34 students were proposed to write an essay on polar matters and invited to attend the II stage of contest. This took place in Seaplane Harbor of Estonian Maritime Museum and lasted 6 hours. There was no access to external information at II stage. The tasks included: answer to 20 questions (similar to stage I) ; to demonstate understanding of popular science paper on hydrological properties of an unusual antarctis lake; to show group work ability solving practical tasks using maps of future expedition activity area. The area was Subarctic Kilpisjärvi region in NW Finnish Lapland. The 5 winners got the award to attend the polar expedition, the others received various polar-related infomation sources and souvenirs. All attendants viewed the maritime rescue exhibition MAYDAY in Seaplane Harbor. The expedition proceeded during 22-30 July 2017, 5 students were accompanied by 3 Polar Club members. Included were visits to several polar institutions: Nanoq polar museum in Pietarsaari (Jakobstad), Arktikum science centre and museum in Rovaniemi, Pallastunturi in Lapland, polar museum and northernmost botanical garden in Tromsö. The science activities were centred during 4-days stay at Kilpisjärvi Biological Station of Helsinki University at 69° N. Students attended hands-on in studies of local geology and limnology. Such studies have been carried out there since 2008 by scientsist from Department of Geology at Tallinn University of Technology. The knowledge contest and the following expedition was rather good covered in social and local media. In August there was a concluding conference in Maritime Museum where expedition participant, Polar Club members, students, relatives and friends, media people and interested public attended. An overview of expedition was given, preliminary research results presented and discussed. The students expressed satisfaction with interesting and horizon-widening experience. At least one of 5 winners declared interest in future studies that could pave way to polar areas. [ABSTRACT FROM AUTHOR]

Purpose: The contact allergens nickel, cobalt, and chromium are often discussed as possible triggers of allergic reactions to orthopedic implants. Additionally, acrylates and polymerization additives in bone cement (e.g., benzoyl peroxide (BPO)) have been implicated as triggers of eczema, wound healing disorders, and aseptic implant loosening. We report about six patients with aseptic loosening after total knee arthroplasty (TKA), who underwent revision surgery after testing positive for BPO hypersensitivity., Methods: After clarification of possible other causes of implant failure, epicutaneous testing had been performed and the implants were replaced in a two-stage procedure with cementless, diaphyseal anchoring, hypoallergenic (TiNb-coated) revision endoprostheses., Results: Epicutaneous testing revealed a BPO allergy in all six patients and an additional nickel allergy in three of the six patients. There was no histopathological or microbiological evidence for a periprosthetic infection. The clinical follow-up showed a low level of pain with good function, a stable knee joint, and proper implant position. The Knee Society Score (KSS) with its subscales Knee Score and Functional Score improved post-operatively from 43 to 70 points and from 47.5 to 68.3 points, respectively. Two implant-specific complications occurred: femoral stress shielding two years post-operatively with no further need for action and aseptic loosening of the tibial stem with the need of revision three years post-operatively., Conclusions: The regression of complaints after replacement with cementless and nickel-free revision implants suggests allergic implant intolerance. Implantation of a cementless, hypoallergenic endoprosthesis might, therefore, be a surgical treatment strategy in patients with evidence of allergies.

The rising number of medical publications makes it difficult to keep up-to-date on scientific knowledge. In recent years, reviews in the form of narrative or systematic publications and meta-analyses have increased. These can only be interpreted and evaluated if the reader understands the techniques used. This review article describes the differences between narrative and systematic reviews, together with the characteristics of meta-analysis, and discusses their interpretation. The concept of systematic reviews and meta-analysis includes a systematic literature search and summary, together with an appraisal of the quality of the publications. Systematic reviews are often considered to be original studies due to their structure and ability to reduce bias., Competing Interests: The authors declare that they have no conflict of interest./Die Autoren geben an, dass kein Interessenkonflikt besteht., (Georg Thieme Verlag KG Stuttgart · New York.)

Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experience periods of snow and ice cover. Relatively little is known of winter ecology in these systems, due to a historical research focus on summer 'growing seasons'. We executed the first global quantitative synthesis on under-ice lake ecology, including 36 abiotic and biotic variables from 42 research groups and 101 lakes, examining seasonal differences and connections as well as how seasonal differences vary with geophysical factors. Plankton were more abundant under ice than expected; mean winter values were 43.2% of summer values for chlorophyll a, 15.8% of summer phytoplankton biovolume and 25.3% of summer zooplankton density. Dissolved nitrogen concentrations were typically higher during winter, and these differences were exaggerated in smaller lakes. Lake size also influenced winter-summer patterns for dissolved organic carbon (DOC), with higher winter DOC in smaller lakes. At coarse levels of taxonomic aggregation, phytoplankton and zooplankton community composition showed few systematic differences between seasons, although literature suggests that seasonal differences are frequently lake-specific, species-specific, or occur at the level of functional group. Within the subset of lakes that had longer time series, winter influenced the subsequent summer for some nutrient variables and zooplankton biomass., (© 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.)