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New optical tweezers trap specimens just a few nanometers wide

New optical tweezers trap specimens just a few nanometers wide | Simply Science | Scoop.it

A technique known as optical trapping uses beams of light as tweezers to hold and manipulate tiny particles. Stanford researchers have found a new way to trap particles smaller than 10 nanometers — and potentially down to just a few atoms in size — which until now have escaped light’s grasp. This new technique allows for studying individual proteins and unraveling them.

To grasp and move microscopic objects, such as bacteria and the components of living cells, scientists can harness the power of concentrated light to manipulate them without ever physically touching them. Now, doctoral student Amr Saleh and Assistant Professor Jennifer Dionne, researchers at the Stanford School of Engineering, have designed an innovative light aperture that allows them to optically trap smaller objects than ever before — potentially just a few atoms in size.

The process of optical trapping — or optical tweezing, as it is often known — involves sculpting a beam of light into a narrow point that produces a strong electromagnetic field. The beam attracts tiny objects and traps them in place, just like a pair of tweezers.

Unfortunately, there are natural limits to the technique. The process breaks down for objects significantly smaller than the wavelength of light. Therefore, optical tweezers cannot grasp super-small objects like individual proteins, which are only a couple of nanometers in diameter.

Saleh and Dionne have shown theoretically that light passed through their novel aperture would stably trap objects as small as 2 nanometers. Saleh is now building a working prototype of the microscopic device.

Dionne says that the most promising method of moving tiny particles with light relies on plasmonics, a technology that takes advantage of the optical and electronic properties of metals. A strong conductor like silver or gold holds its electrons weakly, giving them freedom to move around near the metal’s surface.

When light waves interact with these mobile electrons, they move in what Dionne describes as “a very well-defined, intricate dance,” scattering and sculpting the light into electromagnetic waves called plasmon-polaritons. These oscillations have a very short wavelength compared to visible light, enabling them to trap small specimens more tightly.

Dionne and Saleh applied plasmonic principles to design a new aperture that focuses light more effectively. The aperture is structured much like the coaxial cables that transmit television signals, Saleh said. A nanoscale tube of silver is coated in a thin layer of silicon dioxide, and those two layers are wrapped in a second outer layer of silver. When light shines through the silicon dioxide ring, it creates plasmons at the interface where the silver and silicon dioxide meet. The plasmons travel along aperture and emerge on the other end as a powerful, concentrated beam of light.

The Stanford device is not the first plasmonic trap, but it promises to trap the smallest specimens recorded to date. Saleh and Dionne have theoretically shown that their design can trap particles as small as 2 nanometers. With further improvements, their design could even be used to optically trap molecules even smaller.

Dionne said she would first like to trap a single protein, and try to unravel its twisted structure using visible light alone. Dionne points out that the beam of light could also be used to exert a strong pulling force on stem cells, which has been shown to change how the these important building blocks differentiate into various kinds of cells. Saleh, on the other hand, is particularly excited about moving and stacking tiny particles to explore their attractive forces and create new, “bottom-up” materials and devices.


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Beautiful microscopy / biology images

Beautiful microscopy / biology images | Simply Science | Scoop.it

Beautiful pictures obtained by confocal microscopy provided by the Sean Carroll Laboratory in Madison, WI.

 

http://tinyurl.com/7q5oudy

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Multimodal imaging of human cerebellum - merging X-ray phase microtomography, magnetic resonance microscopy and histology : Scientific Reports : Nature Publishing Group

Multimodal imaging of human cerebellum - merging X-ray phase microtomography, magnetic resonance microscopy and histology : Scientific Reports : Nature Publishing Group | Simply Science | Scoop.it
Imaging modalities including magnetic resonance imaging and X-ray computed tomography are established methods in daily clinical diagnosis of human brain.

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Histosearch: The Histology Search Engine

Histosearch: The Histology Search Engine | Simply Science | Scoop.it

Histosearch searches over 100,000 web pages from histology related sites on the Internet.

 

The Histonet Archives search over 60,000 messages posted to the Histonet listserver since 1998.

 

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Histology-World! Audio Microscope Glossary

Histology-World! Audio Microscope Glossary | Simply Science | Scoop.it
A comprehensive, fun and entertaining site devoted exclusively to histology.
Learning histology was never so easy!

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Single-celled amoebae can remember, make decisions and anticipate change - slime molds redefine intelligence

Single-celled amoebae can remember, make decisions and anticipate change - slime molds redefine intelligence | Simply Science | Scoop.it

Gardeners sometimes encounter them in their backyards—spongy yellow masses squatting in the dirt or slowly swallowing wood chips. Hikers often spot them clinging to the sides of rotting logs like spilled bowls of extra cheesy macaroni. In Mexico some people reportedly scrape their tender bodies from trees and rocks and scramble them like eggs. They are slime molds: gelatinous amoebae that have little to do with the kinds of fungal mold that ruin sourdough and pumpernickel. Biologists currently classify slime molds as protists, a taxonomic group reserved for "everything we don't really understand," says Chris Reid of the University of Sydney.

 

Something scientists have come to understand is that slime molds are much smarter than they look. One species in particular, the SpongeBob SquarePants–yellow Physarum polycephalum, can solve mazes, mimic the layout of man-made transportation networks and choose the healthiest food from a diverse menu—and all this without a brain or nervous system. "Slime molds are redefining what you need to have to qualify as intelligent," Reid says.

 

In the wild, P. polycephalum rummages through leaf litter and oozes along logs searching for the bacteria, fungal spores and other microbes that it envelops and digests à la the amorphous alien in the 1958 horror film The Blob. Although P. polycephalum often acts like a colony of cooperative individuals foraging together, it in fact spends most of its life as a single cell containing millions of nuclei, small sacs of DNA, enzymes and proteins. This one cell is a master shape-shifter. P. polycephalum takes on different appearances depending on where and how it is growing: In the forest it might fatten itself into giant yellow globs or remain as unassuming as a smear of mustard on the underside of a leaf; in the lab, confined to a petri dish, it usually spreads itself thin across the agar, branching like coral. Biologists first brought the slime mold into the lab more than three decades ago to study the way it moves—which has a lot in common with they way muscles work on the molecular level—and to examine the way it reattaches itself when split. "In the earliest research, no one thought it could make choices or behave in seemingly intelligent ways," Reid explains. That thinking has completely changed.

 

Navigating a maze is a pretty impressive feat for a slime mold, but the protist is in fact capable of solving more complex spatial problems: Inside laboratories slime molds have effectively re-created Tokyo's railway network in miniature as well as the highways of Canada, the U.K. and Spain. When researchers placed oat flakes or other bits of food in the same positions as big cities and urban areas, slime molds first engulfed the entirety of the edible maps. Within a matter of days, however, the protists thinned themselves away, leaving behind interconnected branches of slime that linked the pieces of food in almost exactly the same way that man-made roads and rail lines connect major hubs in Tokyo, Europe and Canada. In other words, a single-celled brainless amoebae did not grow living branches between pieces of food in a random manner; rather, they behaved like a team of human engineers, growing the most efficient networks possible. Just as engineers design railways to get people from one city to another as quickly as possible, given the terrain—only laying down the building materials that are needed—the slime molds hit upon the most economical routes from one morsel to another, conserving energy. Andrew Adamatzky of the University of the West of England Bristol and other researchers were so impressed with the protists' behaviors that they have proposed using slime molds to help plan future roadway construction, either with a living protist or a computer program that adopts its decision-making process. Researchers have also simulated real-world geographic constraints like volcanoes and bodies of water by confronting the slime mold with deterrents that it must circumvent, such as bits of salt or beams of light.

 

Compared with most organisms, slime molds have been on the planet for a very long time—they first evolved at least 600 million years ago and perhaps as long as one billion years ago. At the time, no organisms had yet evolved brains or even simple nervous systems. Yet slime molds do not blindly ooze from one place to another—they carefully explore their environments, seeking the most efficient routes between resources. They do not accept whatever circumstances they find themselves in, but rather choose conditions most amenable to their survival. They remember, anticipate and decide. By doing so much with so little, slime molds represent a successful and admirable alternative to convoluted brain-based intelligence. You might say that they break the mold.


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How caffeine affects your creativity.

How caffeine affects your creativity. | Simply Science | Scoop.it

It's common for creatives to pour a cup of coffee before sitting down to work every day, but how does caffeine actually affect creative thinking? In a nutshell:...

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Related post: “I used to drink several cups of coffee a day, but I kicked the habit a long time ago because I found that caffeine made me too jittery and unfocused.” That is a quote by Steve Pavlina, author of one of the most popular, and financially successful, sites and blogs dedicated to personal development... - From my post Caffeine, anxiety, productivity – Steve Pavlina on using Paraliminals

http://talentdevelop.com/375/caffeine-anxiety-productivity/


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Predicting Tamoxifen Resistance In Breast Cancer Treatment

Predicting Tamoxifen Resistance In Breast Cancer Treatment | Simply Science | Scoop.it
Scientists have identified a molecular 'flag' in women with breast cancer who do not respond or have become resistant to the hormone drug tamoxifen.Tamoxifen - used alongside traditional...

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How bacteria talk to each other and our cells

How bacteria talk to each other and our cells | Simply Science | Scoop.it
Bacteria can talk to each other via molecules they themselves produce. The phenomenon is called quorum sensing, and is important when an infection propagates.
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Unexpected factor contributes to melanoma risk in red-haired, fair-skinned individuals

Unexpected factor contributes to melanoma risk in red-haired, fair-skinned individuals | Simply Science | Scoop.it

The elevated risk of melanoma among people with red hair and fair skin may be caused by more than just a lack of natural protection against ultraviolet radiation. Resarchers at the MGH Cutaneous Biology Research Center and Cancer Center have found that the type of skin pigment predominantly found in red-haired, fair-skinned individuals may itself contribute to the development of melanoma.


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Scientists Create “Endless Supply” of Myelin-Forming Cells

Scientists Create “Endless Supply” of Myelin-Forming Cells | Simply Science | Scoop.it

In a new study, researchers have unlocked the complex cellular mechanics that instruct specific brain cells to continue to divide. This discovery overcomes a significant technical hurdle to potential human stem cell therapies; ensuring that an abundant supply of cells is available to study and ultimately treat people with diseases. “One of the major factors that will determine the viability of stem cell therapies is access to a safe and reliable supply of cells,” said University of Rochester Medical Center (URMC) neurologist Steve Goldman, M.D., Ph.D., lead author of the study.

 

“This study demonstrates that – in the case of certain populations of brain cells – we now understand the cell biology and the mechanisms necessary to control cell division and generate an almost endless supply of cells.” The study focuses on cells called glial progenitor cells (GPCs) that are found in the white matter of the human brain. These stem cells give rise to two cells found in the central nervous system: oligodendrocytes, which produce myelin, the fatty tissue that insulates the connections between cells; and astrocytes, cells that are critical to the health and signaling function of oligodendrocytes as well as neurons.

 

Damage to myelin lies at the root of a long list of diseases, such as multiple sclerosis, cerebral palsy, and a family of deadly childhood diseases called pediatric leukodystrophies. The scientific community believes that regenerative medicine – in the form of cell transplantation – holds great promise for treating myelin disorders.

 

Goldman and his colleagues, for example, have demonstrated in numerous animal model studies that transplanted GPCs can proliferate in the brain and repair damaged myelin. However, one of the barriers to moving forward with human treatments for myelin disease has been the difficulty of creating a plentiful supply of necessary cells, in this case GPCs. Scientists have been successful at getting these cells to divide and multiply in the lab, but only for limited periods of time, resulting in the generation of limited numbers of usable cells.


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Fluorescence Microscopy Given New Power

Fluorescence Microscopy Given New Power | Simply Science | Scoop.it

A new method that studies the critical process of cell transport dynamics at multiple spatial and temporal scales has revealed properties of diffusive and directed motion transport in living cells.

 

Using dispersion-relation fluorescence spectroscopy (DFS), researchers at the University of Illinois’ Beckman Institute report an approach that labels molecules of interest with a fluorophore whose motion gives rise to spontaneous fluorescence intensity fluctuations that are analyzed to quantify the governing mass transport dynamics.

 

The data are characterized by the effective dispersion relation, they say.

 

Gabriel Popescu, leader of the university’s Quantitative Light Imaging Laboratory, said the multiplicity of scales the method offers over techniques like fluorescence correlated spectroscopy (FCS) is key.

 

“I think that the beauty of this method is that you can use a commercial fluorescence microscope that is found everywhere to collect and analyze data in a very simple way,” said Ru Wang, a researcher in Popescu’s lab.


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Finnish research organisation VTT combines mobile phone technology and microscopy

VTT Technical Research Center of Finland, the leading multi-technological applied research organization in Northern Europe, has developed an optical accessory that turns an ordinary camera phone into a high-resolution microscope.

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Histology and Immunohistochemistry Protocol Search Engine

Histology and Immunohistochemistry Protocol Search Engine | Simply Science | Scoop.it

FANTASTICO FANTASTIC

 

Search and find thousands of protocols cross major life science protocol sites including protocol-online.org, natureprotocols.com, biologicalprocedures.com, bio.net, ihcworld.com, biowww.net, scientistsolutions.com, immunoportal.com, stainsfile.info, nordiqc.org, and more...

 

The search engine also includes protocols from 100 life science laboratories around the world and covers every aspect in the biological research fields: animal techniques, biochemistry, protein chemistry, cell biology, molecular biology, general lab methods, genetics & genomics, histology, pathology, image techniques, immunology, microbiology, neuroscience, physiology, plant biology, developmental biology, apoptosis, antibody techniques, buffer solutions....

 

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Histology at a Glance by Michelle Peckham

Histology at a Glance by Michelle Peckham | Simply Science | Scoop.it

Histology at a Glance is the perfect guide for medical, dentistry and biomedical science students, junior doctors, and is ideal for independent learning programmes in histology.


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Landmark Study Finds Cause of Hydra Immortality is Linked to Human Lifespan

Landmark Study Finds Cause of Hydra Immortality is Linked to Human Lifespan | Simply Science | Scoop.it

The hydra is a unique multicellular organism. What make it so special is that it is essentially immortal and shows no signs of aging either at the cellular or organism level. It preferentially reproduces asexually, rather than mating it forms buds which break off into progeny. The animal is able to do this by maintaining a continuous robust and unending supply of stem cells.


One theory as to the cause of human aging is the progressive loss of stem cells. Tissue in the body can recover from damage, be it internal or external, through the generation of fresh new cells from division of stem cells residing in niches in those tissues. However with advancing age, eventually these stem cell niches become depleted and the organism, in this case people, reach the end of life.


In the current landmark study, researchers looked to find which genes in hydra are responsible for a never ending supply of stem cells. They discovered this characteristic depends specifically on a gene called FoxO, a fork-head box O transcription factor. This gene is a master genetic switch that when active allows for the expression of many genes involved in cell cycling. When FoxO activity was reduced in hydra they shows signs of aging and cell senescence.


These findings are quite interesting because is has already been shon that a FoxO gene is involved in human aging as well. There is a specific variant of the FoxO3, a human gene that has been linked to extreme human lifespan. It is more commonly found in centenarians.


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Fungal Meningitis Pathogen Developed New Appetite for Human Brains

Fungal Meningitis Pathogen Developed New Appetite for Human Brains | Simply Science | Scoop.it

The primary culprit in the recent flare-up caused by tainted steroids, Exserohilum rostratum, is not an especially picky eater. Although the fungus prefers grasses, it will dine on many items—including human brains.

 

The nation's ongoing fungal meningitis outbreak has killed 30 and sickened 419 people so far, but the fungus responsible has never wrought such havoc before. The fungus, Exserohilum rostratum, is a plant-eating generalist equipped with a spore-launching mechanism ideal for going airborne, is not an especially picky eater and, although it prefers grasses, will dine on many items—including humans. But just how a pathogen typically associated with the great outdoors got into the three lots of injectable steroids prepared inside an admittedly filthy laboratory—and why only three lots—remains a puzzling mystery.

 

The errant fungus has been identified in lab samples from 52 of those affected and was similarly found growing in unopened vials of the steroid alleged to have caused the outbreak, according to the U.S. Centers for Disease Control and Prevention. A third recalled lot is still being tested. But E. rostratum is not a household name, even among mycologists.  The fungus, which seems to prefer tropical and subtropical environments, has turned up on a wide variety of plant species, says Kurt Leonard, an emeritus professor in the Department of Plant Pathology at the University of Minnesota.

 

Most often the fungus shows up on grasses and other monocots—plants often distinguished by flower parts in threes and parallel leaf venation—such as pineapples, bananas and sugarcane, but it has also been found on non-monocots such as grapes and muskmelon. It's a fungus that is not, apparently, very picky about its food. "It's just a really common fungus in the environment that mostly lives on dead and dying plant tissue," Leonard says. There are many such others, and many of them can also occasionally infect animals or people.


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Caffeine: The New Treatment For Parkinson's?

Caffeine: The New Treatment For Parkinson's? | Simply Science | Scoop.it
A new study suggests that caffeine can help control the tremors, movement difficulties, and motor dysfunctions that are typical of Parkinson's sufferers.

...


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Malek Thank You Have A Good Week x
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10 Images That Changed the Course of Science

10 Images That Changed the Course of Science | Simply Science | Scoop.it

One image can change the way we see the world, especially in science. From photographs of movement that's too fast for the human eye to perceive, to atomic force microscope images of atomic bonds, pictures created by new technologies have often catalyzed scientific discovery. More than tools of discovery, though, images can help scientists communicate the reality of what they study to each other and the public. One poignant image can change not just the course of science, but also ordinary people's perception of their place in the cosmos. Here are ten powerful images that did just that.


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9 New Tarantula Species Discovered in Brazil

9 New Tarantula Species Discovered in Brazil | Simply Science | Scoop.it

Nine new species of colorful, arboreal tarantulas have been discovered in central and eastern Brazil, an area where only seven tarantula species had previously been known.


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Cancer cells self-destruct in blind mole rats | Genes & Cells | Science News

Cancer cells self-destruct in blind mole rats | Genes & Cells | Science News | Simply Science | Scoop.it
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