Biscrolling nanotube sheets and functional guests into yarns     

Lima MD  Fang S  Lepró X  Lewis C  Ovalle-Robles R  Carretero-González J  Castillo-Martínez E  Kozlov ME  Oh J  Rawat N  Haines CS  Haque MH  Aare V  Stoughton S  Zakhidov AA  Baughman RH 《Science (New York, N.Y.)》2011,331(6013):51-55

Multifunctional applications of textiles have been limited by the inability to spin important materials into yarns. Generically applicable methods are demonstrated for producing weavable yarns comprising up to 95 weight percent of otherwise unspinnable particulate or nanofiber powders that remain highly functional. Scrolled 50-nanometer-thick carbon nanotube sheets confine these powders in the galleries of irregular scroll sacks whose observed complex structures are related to twist-dependent extension of Archimedean spirals, Fermat spirals, or spiral pairs into scrolls. The strength and electronic connectivity of a small weight fraction of scrolled carbon nanotube sheet enables yarn weaving, sewing, knotting, braiding, and charge collection. This technology is used to make yarns of superconductors, lithium-ion battery materials, graphene ribbons, catalytic nanofibers for fuel cells, and titanium dioxide for photocatalysis.  相似文献   

Do Eurasian minnows (Phoxinus phoxinus L.) inhabiting brackish water enter fresh water to reproduce: Evidence from a study on otolith microchemistry          下载免费PDF全文

Roland Svirgsden  Mehis Rohtla  Anu Albert  Imre Taal  Lauri Saks  Aare Verliin  Markus Vetemaa 《Ecology of Freshwater Fish》2018,27(1):89-97

Dynamics of coastal fish assemblages in the Baltic Sea are still rather poorly understood. In particular, little information is available on migrations and movements of the small‐bodied littoral fish species like Eurasian minnow (Phoxinus phoxinus L.). Minnow is considered typically as a river and lake species, but it also inhabits brackish coastal waters of the Baltic Sea. In this study, we investigated movement patterns of brackish water inhabiting minnows using otolith microchemistry. Fish were collected from four different sites (from two bays and two stream mouths) around Saaremaa Island. The results indicated that at least three distinct migration patterns exist: (i) seawater residency, (ii) fast springtime migrations to fresh water or to bays with lower salinities (areas near stream mouths) and (iii) prolonged migrations to fresh water (some cases overwintering in streams). Migration patterns listed above were not evenly distributed among sites, and some individuals did not migrate to fresh water in every year. None of the analysed fish were freshwater residents. Additionally, potentially ontogenetic effects on Mn and Sr concentrations were observed in the otolith core regions, which may have important implications for the interpretation of otolith chemistry data. The overall findings of this study demonstrate that much more complex migration patterns exists in brackish water inhabiting minnow populations than previously thought and at least some individuals do enter freshwater to reproduce.  相似文献   

Sublethal effects of kaolin and the biopesticides Prestop-Mix and BotaniGard on metabolic rate,water loss and longevity in bumble bees (Bombus terrestris)     

Reet Karise  Riin Muljar  Guy Smagghe  Tanel Kaart  Aare Kuusik  Gerit Dreyersdorff  Ingrid H. Williams  Marika Mänd 《Journal of pest science》2016,89(1):171-178

Kaolin is an inert material with a broad range of applications, e.g. as an insecticide and as a filling substance in the formulation of biopesticides. Hence, bees that dispense biopesticides to the field in the context of entomovectoring are exposed to elevated risks because of side-effects of those products. Here, we investigated with use of bumble bee workers of Bombus terrestris L. the lethal and sublethal effects of (i) pure kaolin, (ii) the biofungicide Prestop-Mix containing the parasitic fungus Gliocladium catenulatum and kaolin and (iii) the bioinsecticide BotaniGard containing the entomopathogenic fungus Beauveria bassiana and compared with wheat flour powder that we considered safe for bumble bees. As the most important result, treatment with kaolin increased the cuticular water loss and reduced the survival of treated bumble bees, while Prestop-Mix had no negative effect on longevity. BotaniGard caused mortality in the bumble bees because of the entomopathogenic spores it contained. In conclusion, our data indicated that substances used as ‘inert materials’ and in biocontrol agents which are used in IPM and organic farming systems may bring higher risks to bumble bees used in entomovector technology.  相似文献   

Parr dispersal between streams via a marine environment: A novel mechanism behind straying for anadromous brown trout?          下载免费PDF全文

Imre Taal  Mehis Rohtla  Lauri Saks  Martin Kesler  Kristiina Jürgens  Roland Svirgsden  Lagle Matetski  Aare Verliin  Päärn Paiste  Markus Vetemaa 《Ecology of Freshwater Fish》2018,27(1):209-215

Otolith Sr:Ca profiles demonstrated that juvenile anadromous brown trout (ABT) Salmo trutta may descend to the brackish waters of the Baltic Sea from their natal streams as parr or fry and then migrate into non‐natal streams before transforming into smolt. To our knowledge, no such published documentation exists for ABT. The ecological significance of this life‐history strategy is presently not clear. However, stream shifting through the marine environment should to be considered with regard to stock management and the assessment and restoration of salmonid populations and their potential habitats.  相似文献   

Annual and seasonal dynamics of fish in the brackish-water Matsalu Bay, Estonia     

M. Vetemaa  R. Eschbaum  A. Verliin  A. Albert  M. Eero  R. Lillemägi  M. Pihlak  T. Saat 《Ecology of Freshwater Fish》2006,15(2):211-220

Abstract –  Matsalu Bay in the Väinameri (West-Estonian Archipelago Sea) is a relatively shallow but large bay. It is the only real delta estuary in the northern Baltic Sea. The fish fauna is strongly dominated by freshwater species such as perch Perca fluviatilis , roach Rutilus rutilus , white bream Blicca bjoerkna and rudd Scardinius erythrophthalmus . The study presents CPUE data describing annual and seasonal variations in the species composition, abundance and spatial distribution, based on 1 year of monthly samplings from August 2001 to August 2002 and routine coastal monitoring (in late July–early August) between 1994 and 2003. The bay can be divided into three rather distinct parts. The fish fauna of the inner part (salinity 0–2 p.p.t.) is different from two open parts and resembles that of freshwater lakes. In the openmost part (salinity usually 4–6 p.p.t.) some marine species, such as herring Clupea harengus membras , flounder Platichthys flesus and eelpout Zoarces viviparus may seasonally be abundant. Species composition and abundance of most species varies seasonally and interannually. Only the abundance of few species such as pike Esox lucius and pikeperch Stizostedion lucioperca was not impacted by seasonality. The most dynamic period in the bay is spring, when several species (some of them very rare in summer, such as herring and smelt Osmerus eperlanus ) enter the bay for spawning.  相似文献