Scientists have found that the way spiders stick to ceilings could be the key to making Post-it® notes that don’t fall off – even when they are wet. A team from Germany and Switzerland have made the first detailed examinations of a jumping spider’s ‘foot’ and have discovered that a molecular force sticks the spider to almost anything. The force is so strong that these spiders could carry over 170 times their own body weight while standing on the ceiling. The research is published today (Monday 19 April 2004) in the Institute of Physics journal Smart Materials and Structures.
A scanning electron microscope (SEM) micrograph of the foot of the jumping spider E. arcuata. In addition to the tarsal claws, a tuft of hair called a scopula is found at the tip of the foot, which is what the spider uses to attach itself to surfaces. The long hairs which are distributed over the entire foot are sensitive to touch
This is the first time anyone has measured exactly how spiders stick to surfaces, and how strong the adhesion force is. The team used a scanning electron microscope (SEM) to make images of the foot of a jumping spider, Evarcha arcuata (pictures available – see notes). There is a tuft of hairs on the bottom of the spider’s leg, and each individual hair is covered in more hairs. These smaller hairs are called setules, and they are what makes the spider stick.
The paper reveals that the force these spiders use to stick to surfaces is the van der Waals force, which acts between individual molecules that are within a nanometre of each other (a nanometre is about ten thousand times smaller than the width of a human hair). The team used a technique called Atomic Force Microscopy (AFM) to measure this force. The flexible contact tips of the setules are triangular (pictures available – see notes), and they have an amazingly high adhesive force on the underlying surface.
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Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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