Toward a Cenozoic history of atmospheric CO.

The geological record encodes the relationship between climate and atmospheric carbon dioxide (CO) over long and short timescales, as well as potential drivers of evolutionary transitions. However, reconstructing CO beyond direct measurements requires the use of paleoproxies and herein lies the challenge, as proxies differ in their assumptions, degree of understanding, and even reconstructed values. In this study, we critically evaluated, categorized, and integrated available proxies to create a high-fidelity and transparently constructed atmospheric CO record spanning the past 66 million years.

Modeling and Analyzing Xylem Vulnerability to Embolism as an Epidemic Process.

Xylem vulnerability to embolism can be quantified by "vulnerability curves" (VC) that are obtained by subjecting wood samples to increasingly negative water potential and monitoring the progressive loss of hydraulic conductivity. VC are typically sigmoidal, and various approaches are used to fit the experimentally obtained VC data for extracting benchmark data of vulnerability to embolism. In addition to such empirical methods, mechanistic approaches to calculate embolism propagation are epidemic modeling and network theory.

Underwater Oleophobic Electrospun Membrane with Spindle-Knotted Structured Fibers for Oil-in-Water Emulsion Separation.

The potential of spider silk as an intriguing biological prototype for collecting water from a humid environment has attracted wide attention, and various materials with suitable structures have been engineered. Here, inspired by this phenomenon, a kind of superwetting poly(vinylidene fluoride) (PVDF) membrane with spindle-knotted structured fibers was prepared by the electrospinning method followed by oxygen plasma etching treatment. The prepared membrane presented a satisfactory separation efficiency for various oil-in-water emulsions.

Straight roads into nowhere - obvious and not-so-obvious biological models for ferrophobic surfaces.

There are currently efforts to improve strategies for biomimetic approaches, to identify pitfalls and to provide recommendations for a successful biomimetic work flow. In this contribution, a case study of a concrete biomimetic project is described that started with a posed technical problem for which seemingly obvious biological models exist. The technical problem was to devise a ferrophobic surface that prevents the contact between the copper surface of a tuyère (a water cooled aeration pipe within a blast furnace) and liquid iron.

When rain collides with plants-patterns and forces of drop impact and how leaves respond to them.

Raindrop impact on leaves is a common event which is of relevance for numerous processes, including the dispersal of pathogens and propagules, leaf wax erosion, gas exchange, leaf water absorption, and interception and storage of rainwater by canopies. The process of drop impact is complex, and its outcome depends on many influential factors. The wettability of plants has been recognized as an important parameter which is itself complex and difficult to determine for leaf surfaces.

The impact of raindrops on leaves: effects of trichomes and elasticity.

The floating leaves of the aquatic fern are covered by superhydrophobic hairs (=trichomes) which are shaped like egg-beaters. These trichomes cause high water repellency and stable unwettability if the leaf is immersed. Whereas hairs are technically interesting, there remains also the question concerning their biological relevance.

A model for extracellular freezing based on observations on Equisetum hyemale.

In frost hardy plants, the lethal intracellular formation of ice crystals has to be prevented during frost periods. Besides the ability for supercooling and pre-frost dehydration of tissues, extracellular ice formation is another strategy to control ice development in tissues. During extracellular ice formation, partially large ice bodies accumulate in intercellular spaces, often at preferred sites which can also be expandable.

Xylem functioning, dysfunction and repair: a physical perspective and implications for phloem transport.

Xylem and phloem are the two main conveyance systems in plants allowing exchanges of water and carbohydrates between roots and leaves. While each system has been studied in isolation for well over a century, the coupling and coordination between them remains the subject of inquiry and active research and frames the scope of the review here. Using a set of balance equations, hazards of bubble formation and their role in shaping xylem pressure and its corollary impact on phloem pressure and sugar transport are featured.

A universal glue: underwater adhesion of the secretion of the carnivorous flypaper plant Roridula gorgonias.

Glandular trichomes of the carnivorous plant Roridula gorgonias release a viscous resinous secretion. Its adhesion to hydrophilic and hydrophobic glass surfaces was measured in air and underwater. The underwater adhesion reached up to 91% (on hydrophilic glass) and 28% (on hydrophobic glass) of that measured in the air.

An analytic model of the self-sealing mechanism of the succulent plant Delosperma cooperi.

After an injury, wound-sealing in leaves of the succulent plant Delosperma cooperi takes place by deformation and movement of the entire leaf within a time span of 30-60 min. In cross sections the almost cylindrical leaves reveal a centripetal arrangement of five different tissue types. Based on anatomical data and mechanical analyses of the five hulls, representing the different tissue layers, we present an analytical model describing the self-sealing process.

Visualization of embolism formation in the xylem of liana stems using neutron radiography.

Background And Aims: Cold neutron radiography was applied to directly observe embolism in conduits of liana stems with the aim to evaluate the suitability of this method for studying embolism formation and repair. Potential advantages of this method are a principally non-invasive imaging approach with low energy dose compared with synchrotron X-ray radiation, a good spatial and temporal resolution, and the possibility to observe the entire volume of stem portions with a length of several centimetres at one time.

Methods: Complete and cut stems of Adenia lobata, Aristolochia macrophylla and Parthenocissus tricuspidata were radiographed at the neutron imaging facility CONRAD at the Helmholtz-Zentrum Berlin für Materialien und Energie, with each measurement cycle lasting several hours.

Sorting of droplets by migration on structured surfaces.

Background: Controlled transport of microdroplets is a topic of interest for various applications. It is well known that liquid droplets move towards areas of minimum contact angle if placed on a flat solid surface exhibiting a gradient of contact angle. This effect can be utilised for droplet manipulation.

Model-based prediction of long-term leaching of contaminants from secondary materials in road constructions and noise protection dams.

In this study, contaminant leaching from three different secondary materials (demolition waste, municipal solid waste incineration ash, and blast furnace slag) to groundwater is assessed by numerical modeling. Reactive transport simulations for a noise protection dam and a road dam (a typical German autobahn), in which secondary materials are reused as base layers, were performed to predict the breakthrough of a conservative tracer (i.e.