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October 05, 2015

Merlots Under the Microscope

Wine can be a catalyst of microscopic and biological tales of fortune, or misfortune, as the case may be.  But while you are popping a cork, let me also pop these wine micro-wisdoms.   So check the vintage, raise a glass, and let’s see how wine looks under a microscope.

Wine micro-wisdoms #1- It takes two separate steps, with two separate yeasts to make a wine

According to the book Molecular Wine Biology,  it’s a two-step process to make a good wine.  Step 1 involves the yeast in primary fermentation; saccharomyces yeasts in an aerobic environment.  A very specific yeast is used with genetic markers to monitor that ensure development of the wine remains the same from batch to batch. This is where saccharomyces does 70% of her work to make a good wine and occurs within 5-7 days.  Yeast and air are both key ingredients to how saccharomyces reproduce at the proper rate.

Picture Source: http://wineserver.ucdavis.edu/industry/enology/winemicro/wineyeast/saccharomyces_cerevisiae.html

The second stage of development, or secondary fermentation, is an anaerobic process and lasts 2-3 weeks. Air exposure must be at a complete minimum for this process to work; as saccharomyces eats all the available sugars and nutrients.

Wine micro-wisdoms #2- Wine’s oldest cellar was found in Armenia 

A vintage not likely to be found by collectors, the earliest wine making supplies were found in Armenia and date back to over 6000 years ago. If you can imagine, there were humans 6000 years ago that were already harvesting micro-biology to human will! The wines did have a lot in common with the modern day wines, they used grapes that were nearly identical genetically to wine grapes we use today.

Wine micro-wisdoms #3- Today’s food preservation was a direct result of wine

In 1852, Napoleon III wanted to find a  cure for the dreaded “wine diseases”.  Wine diseases, particularly wine souring, were making wine unpalatable.   The Emperor commissioned Louis Pasteur to find a cause and solution to the unsavory wine problem. Lois Pasteur realized that there were specific micro-biology present in the wines that were affected by wine souring; and therefore created his famous process of applying heat and minimizing exposure to bacteria in the atmosphere now known as pasteurization.

Wine micro-wisdoms #4- Olive oil was used to prevent oxidation

When wine is exposed to oxygen for long periods of time, oxidation occurs. This process occurs as the tannins  are oxidized, producing hydrogen peroxide and the ethanol (the actual alcohol part of  the wine) is changed into acetaldehyde.  Prior to our uses of corks to resolve this issue, the Roman used olive oil as a fix for oxidation in wines.  In fact, the oldest known bottle of wine dates back from 325 A.D. and has a large film of olive oil to reduce the wine’s breakdown.

From the earliest known harnessing of microbes for the benefits of humans, to pasteurization, to olive oil, wine plays a pretty interesting role in microscopic and chemical applications today.  So if your of age, go ahead and open a bottle, grab a glass, let it breathe and enjoy…….responsibly, of course!

September 28, 2015

Battling Bad Bacteria

 

Staphylococcus aureus (MRSA) Bacteria.jpg

Bacteria has been infecting the news lately. From flesh eating bacteria in Florida to the deadly Legionnaires’ Outbreak in New York, it seems as though Bacteria has some pretty bad PR. Bacteria, however, also helps us digest, is a primary ingredient in cheese production, helps with crop management and may be the future of green energy. However, bad bacteria, is what we want to focus on today. The kind that we wish we were killing when we use 99.9% effective hand sanitizer. Science Daily recently posted two articles that have interesting perspectives at how Bacteria affect our bodies and the future for killing bacteria.

First, Ohio State University. The Buckeyes have studied how efficient Bacteria are in attacking our human bodies. An article in Science, in July this year, outlined the deadly patterns of certain bacteria in their war on the human body. The Bacteria in the study attacked certain protein actin causing them to turn toxic to our immune systems. This process has allowed many of the most notorious diseases to spread faster and be harder to cure: Cholera, Septicemia, and similar diseases are affecting the human body by making the proteins “defect” against their own body.  According to Johnson et. al in Molecular Biology of the Cell 5th Edition, actin could be the key to muscular diseases, and some functions of the heart. These internal assaults makes it harder for the immune system to combat bacteria because they reduce the level of contact with the immune system. Read more detail in the study at Bacteria Article.

As has been widely publicized, an increasing number of bacteria are becoming antibiotic-resistant, a problem of huge consequences especially in hospitals where bacteria are rife. Researchers at Rice University are working to identify the mutations that lead to antibiotic-resistant bacteria. The hope is by identifying the routes of mutations, they can be counter-acted faster and allow for continued use of certain antibiotics that would otherwise be deemed ineffective. Using a bacteria and antibiotic combination that is rarely combined, Rice researchers were able to predict the Horizontal Gene Transfer that was used by the bacteria to evolve a resistance to certain drugs. Not only was a single bacterium surviving to become resistant; it was able to take its successful genome and transfer it on to other bacteria cells. This increased the rate of observation of resistant bacteria in the samples beyond a simple paternal exchange of genetic information; the bacteria parents were talking to each other.

Such genetic recoding continues as we look how other bacteria (such as the “good” bacteria, Bacillus subtilis) are redesigning their genetics with Programmed cell death (PCD) in bacteria. This PCD pass from the “mother cell” and serves to aid development, advance genetic variations, and decrease unfavorable mutations. These could be good in the case of yeasts as PCD could be favorable to populations; however, unfavorable in other situations. According to the Author: The concept of programmed death in bacteria prompts us to reexamine a broad range of important yet poorly understood phenomena in the life of microbial cells, such as the mechanism of killing by antibiotics, the role of a low mutation rate, death and survival at stationary state, the nature of persistence, and the related issues of population survival and biofilm resilience. These studies only go to show the world of micro biology is far from being fully understood. We are finding more ways daily how bacteria are attacking us, how it is evolving around antibiotics, and even systematically programming their cell deaths themselves along their own genetic patterns.

We can only hope that we can work harder to think big, by studying small.

August 18, 2015

New, Oldest Flowering Plant

Montsechia vidalii. Photograph Gomez et al/PNAS

Montsechia vidalii. Photograph Gomez et al/PNAS

New analysis of a fossilized plant found in Central Spain and the Pyrenee Mountains indicate that it may be the world’s first known flowering plant. At 125-130 million years old, Montsechia vidalii dates back to the start of the Cretaceous Period when feathered dinosaurs roamed Earth.

Previously, the oldest known flowering plant was Archeafructus sinensis, found in Liaoning province, China and which dates from 125 million years ago. Like Archeafructus sinensis, Montsechia vidalii grew underwater in shallow lakes and appears to have no roots or petals and only one seed per flower. Its leaves formed either in a spiral or opposite one another.

To get to the fossilized plant, study the ancient plant, Dilcher and his team painstakingly dissolved the limestone around more than 1000 fossils on a “drop-by-drop basis”. The resulting plant fragments were then examined under both light microscopes and scanning electron microscopes.

The plant has been known for years. First discovered over 100 years ago, Dilcher reports that it was misdiagnosed because it “possesses no obvious flower parts, such as petals or nectar-producing structures for attracting insects, and lives out its entire life cycle under water.”

Montsechia vidalii. Photograph Gomez et al/PNAS

Montsechia vidalii. Photograph Gomez et al/PNAS

This is what makes it interesting. As Dilcher pointed out, at that time animals had not developed any role in dispersing seeds. How the plants were fertilized and reproduced may help us understand and mitigate against the risk of pollinator failure in the modern day. Dilcher thinks the plant had separate male and female flowers. The seeds may have been released straight into the water and then floated away to fertilize another plant.

“We need to understand as much as we can about flowering plant evolution because right now we’re facing a world crisis.” Says Dilcher. Most present-day plants require animal pollinators and of course, bees, which are critical, food crop pollinators are declining in Europe and the US.

“This plant shows us where it all began,” says Dilcher. “If we know more about their evolution, we might come across alternative pollinators that are hidden out of sight today but played a role in the past that we could encourage again.”

Journal Reference:

  1. David L. Dilcherd et al. Montsechia, an ancient aquatic angiosperm.PNAS, August 2015 DOI: 10.1073/pnas.1509241112
August 17, 2015

Fertile Fungus that’s Saving the World

Mycorrhizal Image

Mycorrhizal Image: Courtesy of Soil and Water Conservation Society (SWCS). 2000. Soil Biology Primer. Rev. ed. Ankeny, IA: Soil and Water Conservation Society.

Let’s talk about fungus. Fungus is more than mold in your bathroom, or yeasts in your breads; fungus plays an ever expanding role on global ecosystems and agriculture.  Cambridge University released a study this May that shows fungus may reduce water eutrophication and increase crop yields.

Within soils are a myriad of microscopic biology. One family of microscopic organisms, mycorrhizae, is a symbiotic soil fungi that attaches itself to vascular roots of plants all across the world.  The mycorrhizae was first recognized in the mid-19th century; however, scientists are still learning how they react with crops and wildland ecology.

Rice plants that were “colonized” with mycorrhizae triggered genetic expressions to change in the rice plants, as a result of which both the root mass and Phosphorus intake increased up to 70%-100%.  Why is this important?  Because of 16 essential nutrients that are needed for plants, Phosphorus (along with Nitrogen), is one of the most critical and due to its importance, it is characterized as a macro-nutrient.  Phosphorus is a component of the photosynthesis proteins and is used by the plant for cell division and new tissue development. In other words – growth.

Phosphorus, however, is one of the most detrimental nutrients to the environment when applied incorrectly.   It is mined heavily for agricultural uses and, via run-off, it is one of the leading causes of water pollution. The heavy concentration of nitrogen and phosphorous in run-off causes eutrophication of rivers and lakes and is the leading cause of resulting algae blooms, hypoxia and die-off all affected aquatic life. We have all seen pictures of the thousands of dead fish floating under such conditions.

By creating a more efficient soil system with mycorrhizae, the hope is that less applied phosphorous will be needed with a corresponding slower depletion rate of Phosphorous through mining and less environmental pollution via run-off.

Redwood Mycorrhizae

Redwood Saplings without and with Mycorrhizae: Courtesy of M. Amaranthus, USDA

The Cambridge researchers plan to inoculate agricultural land with mycorrhizae with a view to increasing crop efficiency of the top crops such as rice, wheat and corn.  The idea is to improve yields with less need for applied phosphorous and ultimately to reduce famine in areas where mycorrhizae have been depleted or where mycorrhizae can be utilized for higher crop efficiency. In particular, mycorrhizae might help sustain crops in arid regions, which is an issue that takes on greater significance with changing global rain patterns.

Not bad for a fungus? A significant contributor toward improved crop yields, a possible solution to marginal areas of agriculture AND an environmental savior for that much-overlooked part of the world….water.

Want to see how mycorrhizae looks in a microscope?  Check out this guide on how to identify and view them in stereo microscopes here.  You will need a stereo dissecting microscope, which can be found here at Microscope.com.

Learn more about the Cambridge Study on Cambridge’s Website at: http://www.cam.ac.uk/research/news/fungus-enhances-crop-roots-and-could-be-a-future-bio-fertiliser

March 05, 2014

QUANTUM MICROSCOPES – LIGHT YEARS AHEAD

At Microscope.com we often say that the technology of light microscopes has not changed much over the past 500 years. Strictly speaking, this is no longer true. Scientists at Hokkaido University in Japan have found a way to use ordinary light to detect objects smaller than the limit of traditional light microscopes. Up until now, light microscopes have been limited by the Rayleigh diffraction limit, which states that light cannot be used to resolve a structure smaller than its own wavelength. Since the shortest wavelength of visible light is a few hundred nanometers, scientists have turned to X-Rays and electron microscopes in order to resolve smaller elements.

However, for some time scientists have suspected that a weird effect of quantum mechanics known as entanglement might overcome the Rayleigh limit and the Hokkaido team have done just that. Einstein referred to Entanglement as “spooky action at a distance”. It involves two photons in opposite polarization states that become entangled so that even when separated by infinitely large distances (think light years), changes to one are reflected in the other. Using such entangled photons, the microscope visualizes much smaller structures than could be achieved with ordinary light.

In this case, the scientists generated entangled photons by converting a laser beam into pairs of photons that were in opposite polarization states at the same time (superposed particles). The physicists used special nonlinear crystals to achieve this superposition and then focused the entangled photons on two adjacent spots on a flat glass plate with a Q-shaped pattern made in relief on the plate’s surface. This pattern is only 17 nanometers higher than the rest of the plate and almost impossible to see with a standard optical microscope. However using the entangled pairs, the lettering was completely visible and 1.35 times sharper (signal-to-noise ratio) than the standard quantum limit.

entangled-microscope

Inevitably, obtaining an image was not as simple as using an eyepiece. In this case, the team generated the image electronically by measuring the difference in optical path length between the two beams, a difference that is caused by the marginally thicker glass where the letter rises up from the surrounding surface. The scientists could not measure this directly, so they used the interference pattern of both beams as they passed through the glass. Since each of the entangled protons provides information about the other, the process is more efficient and results in a sharper image.

The major drawback to the process is that it took almost a full day for the microscope to generate actual images so a key improvement for commercial development is the ability to speed image development. However, the team has proven that the refractive index of light microscopes can be enhanced which could have a major beneficial impact on Life Sciences and other disciplines such as cryptography. Currently, in order to observe transparent organisms in such detail, X-Rays or electron microscopes are required. Both are expensive while X-Rays cause damage to living cells. Since this entangled photons approach uses simple lasers with infrared rays, it offers both an inexpensive and harmless solution to future generations.

[Research paper: 10.1038/ncomms3426 – “An entanglement-enhanced microscope”; open-access PDF]

November 21, 2013

Tears under a Microscope

Basal tear, photo Rose-Lynn Fisher, courtesy of the artist and Craig Krull Gallery, Santa Monica CA

Occasionally…. very occasionally amid the deafening ‘noise’ of irrelevant blogs, tweets and posts, I stumble across a real gem, a testament to the power of human curiosity and creativity. Rose-Lynn Fisher’s microscopic study, The Topography of Tears is one such gem.

Inspired by her own “period of personal change, loss and copious tears”, Fisher was curious about whether tears of grief looked different from tears of joy and laughter. Not content with just being curious, she photographed 100 tears using a standard compound microscope. Many were her own tears. Some were from friends and at least one from a baby. Her conclusions were not just scientifically interesting, but poetic; her writing is as good as her photographs and it is worth reading her description of the project.

Laughing tear, photo Rose-Lynn Fisher, courtesy of the artist and Craig Krull Gallery, Santa Monica CA

Science divides tears into three categories:

  • Physic tears such as grief and joy, which are triggered by extreme emotions
  • Basal tears which the eye releases continuously in tiny quantities as a corneal lubricant
  • Reflex tears in response to irritants such as onion vapors and dust.

As most people know, tears are in essence salt water, but they also contain a variety of oils, enzymes and antibodies. Physic tears, for example, contain hormones such as prolactin (associated with milk production) and the neurotransmitter leucine enkephalin which acts as a natural painkiller when the body is under stress.

These different molecules account for some of the differences that Fisher photographed. In addition, the circumstances and setting of how the tear evaporates determines the shape and formation of the salt crystals so that two identical tears can look entirely different close up.

So much for the science!

For Fisher, tears are more poetic and “evoke a sense of place, like aerial views of emotional terrain……..a momentary landscape, transient as the fingerprint of someone in a dream. This series is alike an ephemeral atlas”. Like Fibonacci numbers, Fisher sees a repetitive pattern in tears similar to the earth’s topography. ” I marvel….how the patterning of nature seems so consistent, regardless of scale. Patterns of erosion etched in to the earth over millions of years may look quite similar to the branched crystalline tears of an evaporated tear”.

Onion tear, photo Rose-Lynn Fisher, courtesy of the artist and Craig Krull Gallery, Santa Monica CA

“It’s as though each one of our tears carries a microcosm of the collective human experience, like one drop of an ocean. “

Tears of grief, photo Rose-Lynn Fisher, courtesy of the artist and Craig Krull Gallery, Santa Monica CA

What I particularly admire is that Fisher translated what started as idle curiosity into substantive action with  a result that is as beautiful as it is interesting. The idea is ingenious, but the execution is relatively simple, easily within the realm of the average family.

I would encourage you to try this experiment at home and send us your resulting images. After all, the Holidays is a time of extreme emotions all round, when tears of joy and grief abound.

November 07, 2013

Mount Toba – Super Volcano

The Jakarta Times reported, yesterday that geologists fear that Mount Toba, on Sumatra may erupt again as a super volcano. Toba has already accounted for the largest known earthquake in the last 2 million years when it spewed out more than 2,500 cubic kilometers…that’s kilometers, not meters….of magma and which ultimately resulted in the formation of  the world’s largest quaternary caldera’s (35 x 100 km) that is now Lake Toba.

The scientists, who include Craig A. Chesner of Eastern Illinois University have identified a huge magma chamber at a depth between 20-100 kilometers. The concern is that one of the frequent earthquakes in the region could set off an eruption, which would have potentially devestating consequences.

Anau Krakatau 2009 - Photo: Iris Karinkanta

Indonesia consists of more than 13,000 islands, spread over an area the size of the United States. It has the greatest number and density of active volcanoes with 129 being actively monitored by scientists. Most volcanoes in Indonesia stretch from NW Sumatra (including Mount Toba), to the Banda Sea and are largely the result of the subduction of the Indian Ocean crust beneath the Asian tectonic plate.  As if this were not enough, there are other subductions that make the picture more complex and….more dangerous.

Unsurprisingly, it also has the largest number of historically active volcanoes (76), and the second largest number of dated eruptions (1,171)  exceeded marginally by Japan (1,274).  Indonesian eruptions have also caused the highest number of fatalities, damage to arable land, mudflows, tsunamis, domes, and pyroclastic flows. 80% of such dated eruptions have erupted since 1900 although such analysis only stretches back to the 15th century!

Volcanic Rocks, Courtesy of Microscopy4kids.org

Two of the most cataclysmic volcanic eruptions in recent history include the devestating eruption of Tambora in 1815 which altered the world’s weather to such an extent that, in Europe, 1816 became known as ‘the year without summer’. More famous was the  disastrous eruption of Krakatau in 1883, not so much due to the magnitude of the eruption as to the magnitude of the tsunamis. Tsunamis accounted for 30-40,000 lives and secured Krakatau’s place in the collective memory of the world.

All of these volcanic eruptions create igneous rocks of one kind or another. Under a microscope, they can help tell the story of what happened and when while also presenting a glorious array of colors and crystals. Polarizing microscopes are best used for examining such rock specimens but surface textures an colors can be viewed with our new Explorer Series Rock Hound packages.

Explorer Pro Rock Hound Microscope Package

August 28, 2013

CICADA KILLER WASPS

 

Microscopic view of cicada killer head

Eastern Cicada Killer Wasp

Danny brought in this beauty, last week and we took the opportunity to snap a few images under various microscopes.  It looks intimidating, but is harmless in spite of the females having a large stinger. It is an Eastern Cicada Killer wasp, which exists to cull some of the annual cicada population. The female uses her stinger to paralyze a cicada prior to flying it back to her nest which is an amazing sight since the cicada is typically significantly larger than the wasp itself. As a result, she hauls it up a tree and then launches herself off towards her burrow, often repeating this laborious process several times in order to get there. Each male egg gets one cicada and each female at least two cicadas. Unsurprisingly, the female wasps are larger than the males.

Cicada Killer Burrow

You can always identify cicada killer wasps not only due to their size (up to two inches), but due to their burrows which always have a mound of earth outside along with a characteristic trench running through it to the hole. And there will be lots of them, too…….thousands at our last house!

Leg Spines

As you can see, up close under a microscope, they are beautiful. The spines on their legs serve to help the females dig their burrows. They use their powerful jaws to loosen the soil and then excavate the soil using their legs. Hence the mound outside although they also use excavated earth to seal their egg chambers.

We used a Dino-Lite AM4113T to view this one as well as one of our new Explorer Pro digital microscopes that we will be launching soon.

August 26, 2013

Birth of the Electron Microscope Part 3: The Scan

The creation of the transmission electron microscope (TEM) was a revolution in the field of microscopy; for the first time, it allowed humans to see things that were too small for traditional light-based microscopes to resolve, such as individual cells and large atomic molecules, by exposing samples to a beam of electrons instead of a beam of light. However, the TEM had limitations of its own; it could only resolve an image if the sample was thin enough for electrons to pass through, so biological samples had to be preserved and sliced up, destroying any potential for viewing the minute changes in a living organism and making it impossible to view a complete image of the specimen. TEM also suffered from diffraction issues, as the electron beam could only resolve to a certain magnification level before the electrons scattered too much to form a definite image.

Shortly after the TEM’s 1931 debut, a Russian scientist named Manfred von Ardenne invented a true electron-based microscope that worked on a slightly different principle, and patented the Scanning Electron Microscope (SEM) in 1937. This machine finally enabled scientists to see complete specimens in high detail, and resolve three-dimensional shapes. Instead of relying on a beam of electrons to carry the image away from the specimen, the scanning electron microscope works by scanning the beam across the specimen in a series of rectangular areas. This technique is known as raster scanning, and it is common in computer graphics; it’s how printers create images on paper, and how older CRT televisions created their images. When an SEM scans a specimen, the electron beam loses energy; this energy is converted into heat, scattered electrons, X-rays, and light emission. The SEM’s lenses can detect this energy, and it maps these signals into an image based on where the electron beam was located when it lost that particular amount of energy. By scanning in this manner, an SEM can resolve specimens as three-dimensional shapes.

The specimens in an SEM must be electrically conductive, in order to attract the electrons in the first place. While metals require very little preparation, non-conductive specimens must be coated with a very thin layer of gold, platinum, or tungsten. The SEM uses an electron gun much like the TEM, and uses a tiny cathode of tungsten at its tip. The SEM also requires the specimen to sit in a vacuum, in order to prevent interference from artifically disrupting the electron beam.

There are other types of electron microscopes, but the SEM was a major breakthrough because it allowed researchers to capture minute details of things like a house fly’s eye, a snowflake, or an ant’s head. Special environmental SEMs can observe samples that are in low-pressure environments (rather than complete vacuums) and do not require biological materials to be coated in gold. It is highly useful for seeing biological specimens, even scanning still-living insects.

May 23, 2013

Electron Microscopy – Part 1

In today’s modern era, it’s almost impossible to imagine a time when we didn’t know about microscopic particles and structures; magnification is a fundamental part of everyday life, from a pair of reading glasses to the side mirrors on a car. With the birth of the optical microscope in the 17th century, scientists were able to meticulously document, research, and discover a world of things normally invisible to the naked eye. It seemed as though the wonders of the microscopic was infinite – until the 1930s, when it became clear that optical microscopy wasn’t telling the entire story. There were forces at work that were far too small for even the most powerful lenses to see; at some point, the image simply couldn’t resolve clearly. It seemed as though optical microscopes had been pushed to their furthest possible limits. But how could something be too small for light to see, and how could you possibly examine it?

This set of problems was the catalyst for scientists to begin branching out from light-based microscopy. The theoretical framework explaining the limits of light-based magnification were already in place. The issue lay in understanding how light worked, and why it failed at certain magnifications. Visible light is electromagnetic radiation, part of a wide spectrum of rays that stretches from radio waves to X-rays, microwaves, gamma rays, and more. All EM Radiation is made of particles called photons, which travel in a wavelength; the speed and frequency of that wave will determine what sort of radiation it is, and how it interacts with various objects. X-rays, for instance, have a wavelength that is too short to bounce off of human flesh, but does reflect dense material like bone, allowing the doctor to clearly see your broken wrist. UV radiation can penetrate the skin enough to cause a sunburn, but we can’t see the rays with our eyes.

We are able to see objects because visible light bounces off of them and returns to our eyes. When that wavelength encounters an object, like a sample on a slide or the magnifying lenses of a microscope, the interference will cause the wave to spread out and weaken. As the light passes through a smaller and smaller space, it will scatter more and more. This phenomenon is called diffraction, and it is the major limit of optical microscopy: at a certain point, the photons are just too big and clunky to accurately bounce off of the sample and resolve clearly.

All of this was proven in 1873, when physicists Hermann von Helmholtz and Ernst Abbe demonstrated that optical resolution was dependent on the wavelength of the light source. They posed the crucial question: what if you could somehow use an illumination source that had a smaller wavelength than light? It was purely theoretical; the existence of electrons wasn’t proven until 1896. But the idea stayed around in various scientific circles; the theory that electrons could travel in a wave was proposed in a 1924 paper, and in 1926 German scientist Hans Busch showed that magnets could be used to direct a stream of electrons in a specific direction. The problems were in place and the theories were quickly being proven: it wouldn’t be long before scientists broke through the limits of light and found a way to see the invisible all over again.

May 20, 2013

Immersion Oil Explained

We are often asked about immersion oil so here is a basic primer. Immersion oil is used with high power objectives, typically 90x or 100x.

Light microscopes have an upper limit to their resolving power of marginally over 1,000x. At this level of magnification, the microscope needs to direct every available amount of light in order to achieve a clear image. Since light is refracted and scattered in the air between the objective lens and the slide cover, immersion oil is used to capture much of that ‘lost light’.

In summary, light refracts through air and glass at different angles. The refractive index of air is 1.0 and that of glass, 1.5 so there is considerable refraction between the two. The immersion oil helps to reduce the refraction since it has a refractive index equal to glass. As a result, it forms a continuum between the objective lens and the slide, thereby successfully ensuring that more light is directed towards the specimen and ultimately, a clearer image.

Oil immersion objective lenses are typically engraved with the word “oil”, “immersion” or “HI” (homogenous immersion). They are manufactured with sealants to prevent damage from the oil.
Immersion oils are commonly available in two viscosities-low viscosity (Type A), and high viscosity (Type B). They are often labeled with a refractive index of 1.515. The low viscosity oil is applied to the airspace between slide and objective, the high viscosity oil is applied between the condenser and the slide.

How to Use it: Type A – Low Viscosity Oil

The majority of applications require Type A oil, which can be used as follows:

  1. Locate a specimen on the slide and center it in the image field.
  2. Rotate the nosepiece until the 100x objective lens is just to one side of the slide. Place a single drop of immersion oil on the slide cover slip and place a drop directly on the objective lens. Combined, both drops ensure no air is trapped in between.
  3. Rotate the 100x objective into place and adjust the fine focus to fully resolve the image.

Cleanup

It is very important to carefully clean the oil off your objective lens before it dries.

  1. Carefully wipe oil from all glass surfaces with a folded piece of clean lens paper.
  2. Moisten a piece of lens cleaning paper with lens cleaning fluid and wipe away any residual streaks of oil.
May 08, 2013

Crunchy Cicada Anyone?

Any day now, an invasion will begin. Unsuspecting people up and down the Eastern seaboard from New England to North Carolina will run for cover. Weddings will be interrupted. The news channels will work themselves into a frenzy – and your lawns, trees and gardens will buzz with bulging, red-eyed invaders. Martians? No. Simply, the hatching of billions of Magicicadas.

Cicada on leaf

Photo Credit: US Dept. of Agriculture

For the past 17 years, billions of the inch-long bugs, which entomologists ominously refer to as “Brood II”, have been lying dormant underfoot. Quietly munching away on tree roots and vegetation 2-3 feet below us, they have awaited Mother Nature’s call to complete their 17 year life cycle.

That call happens when the soil temperature in their underground home climbs above 64 degrees Fahrenheit. Over the course of the next few weeks, billions of them will emerge and swarm with the primeval goal of mating before they die. Despite their ghoulish looks, they actually are quite harmless to humans and animals. For the most part, they hang out in trees and shrubs for a few weeks and then die, at which time their offspring venture underground to begin another 17-year cycle.

Photo Credit: Tenn. Farm Bureau

Even though this year’s brood is forecast to number in the billions, most of us won’t even see them. We most definitely will hear them. The male Cicada makes music by pushing air through vibrating organs in their abdomen, and quite effectively at that. As they sing their mating cry, a tree filled with males can fill the evening with sound volume approaching 90 decibels!

Apart from their rare appearance and song, what exactly are Cicadas good for besides water-cooler commentary? Well for starters, they’re edible! They are eaten by a wide variety of animals…….including humans. While not quite rising to the popularity of chocolate-covered crickets, they still hold their own at the adventurous dinner table. In fact their hearty flavor, which some intrepid souls describe as asparagus-like, can be found in a surprising variety of dishes like cheese, quiche, casseroles and

even dessert, for those ardent aficionados. Apparently, they are best eaten immediately after hatching which typically, occurs at night. Luckily, they are quite torpid after hatching so they can easily be scraped off the tree branches.

Photo Credit: Smithsonian Institute

Abundant food, totally organic, nutritious, free and hilarious……..it didn’t take long for us here at Microscope.com to decide to hold a contest for the best Cicada recipe.

So dust off your family’s favorite Cicada recipe and send it in. We’d love to hear about it and you could have a chance to win a new microscope. One more reason to enjoy this “Season of the Cicada”…or should that be Cicada Seasoning? Bon Appetite!

Just send us an email, with recipe attached, to [email protected], anytime between now and the June 15, for your chance to win a new Omano OM115 compound microscope. The winner will be announced in a followup blog post.

April 29, 2013

History of Photomicrography

We’re surrounded by an abundance of technology, nowadays so it can sometimes be hard to imagine what it was like to look through a microscope for the very first time in the 1600s. Before the invention of the compound (multi-lensed) microscope, people believed that the world was comprised solely of what could be seen with the naked eye; it must have been overwhelming to realize what humanity had been missing! Once optical microscopy took off, scientists could finally get a detailed look at everything from well-known insects to completely new bacteria and understand how the tiny structures of a material affected its behavior.

Scientists are well-known for conducting experiments and documenting every detail of their actions. So it’s not surprising that the great analytical minds of the day began to sketch out the details of what they saw under the microscope  in order to preserve the images for future reference. These images came to be known as micrographs, and they have evolved alongside the microscope in terms of their level of detail and use of technology.

Initially, micrographs were hand-drawn sketches detailing what the observer saw on the slide. One of the first known images made with a microscope was drawn by Francesco Stelluti, who published a sheet of bee anatomy in 1630. Thirty-five years later, scientist Robert Hooke wrote and published Micrographia, the first major book about microscopy. The tome detailed his observations: the eyeball of a fly, a plant cell, insect wings, and a huge fold-out engraving of a louse. Micrographia was a monumental best-seller that also coined the biological term ‘cell’ after Hooke’s famous inspection of a piece of cork.

Basic sketches remained an easy method for documenting microscopic images for many years. When photography technology caught up, people would often simply hold a standard camera up to a microscope eyepiece and take a picture; after all, the camera was designed to resemble the viewpoint of a human eye, so it made sense to try to capture the slide permanently by exposing it to film. This technique is called the afocal method’. A typical optical microscope emits parallel light rays from its source up into the ocular, so an image can be created using a camera that is made for capturing very distant objects; those lenses are designed to work with parallel light as well. The eyepieces of both the ocular and the camera must be carefully chosen to work together to capture a clear image.

The direct imaging method is far more straightforward: both the eyepiece of the microscope and the lens of the camera are removed, and the camera is placed on the microscope tube so that its shutter surface matches the primary image plane projected by the microscope. You can also purchase mechanical adapters, which attach the camera to the microscope tube directly and allow for a much clearer method of focusing. Digital photography has made micrographs much easier to produce. Modern microscopes may contain a built-in camera and USB connection, which will allow you to plug them into a computer and record images directly onto the hard drive. However, a more flexible approach is to buy a standard microscope and add an external microscope camera. That way, you can use different cameras on the same microscope and vice versa. As important, you do not need to buy an entirely new unit if the camera software fails. Whatever your method, microscope imaging, or photomicrography, has grown and changed alongside microscopy, recording humanity’s findings for future research and posterity.

April 22, 2013

MICROSCOPE DO’s AND DON’T s

A microscope can change a student’s life forever and introduce your child to the smallest wonders of the world around him or her. But microscopes aren’t toys; even the simplest student-oriented device contains some very delicate parts. It’s important to learn how to handle and care for your new microscope properly, so that you can enjoy your device for years to come. Here are a few basic do’s and don’ts for two of the most important parts of a microscope: the illumination source and the lenses.

Light Sources
Light microscopes need a light source to illuminate the sample you are viewing. Modern microscopes typically employ tungsten, halogen or LED light bulbs. Field microscopes can employ ambient light although the first rule is never to use your microscope outside in direct sunlight as it can damage your eyes.  Halogen microscope bulbs can become very hot to the touch. If you need to replace the light source, turn off the microscope first and unplug it; this will allow the bulb to cool and prevent possible electric shock. Always use the correct light bulb; different brands require different bulbs that are calibrated to work with the lenses, so trying to swap out one type for another may cause damage to the microscope. Use your microscope in a well-lit room, and always place it on a flat surface.

Lenses
The lens of a microscope is the engine of the microscope. without it, your magnification efforts are futile. Compound microscopes have two types of lenses: the eyepiece, or ocular, which is what you look through; and the objective lenses, which are the primary magnifiers and are typically positioned directly above the stage on which the specimen will sit. Most compound microscopes include between three and five objective lenses that are mounted on a rotating turret. Magnification is achieved by multiplying the value of the eyepiece by that of the objective lens. For example, a 10x eyepiece and a 100x objective lens creates 1,000x magnification.

All microscope lenses are delicate and should never be touched with bare hands. If the lenses have dust or oil on them, clean with special lint free, lens tissue and a microfiber soft cloth. Neither of these will scratch the glass the way normal tissue paper would. Lenses can be damaged through improper cleaning techniques so it is important to use correct materials and if necessary. Begin by blowing away any dust using compressed dry air; there are some high-grade canned air products made specifically for optical equipment.  Moisten the lens tissue with a solvent-free  lens cleaning fluid and never dry wipe the glass.

Some microscopes use immersion oil, which reduces the amount of light refraction and provides a clearer image of the sample. This technique is achieved by immersing both the objective lens and the specimen slide in the oil. Always make sure to clean all of the oil from the slide and the lens once you are finished; any leftover residue can flow into the microscope casing and damage its components. Follow the instructions for oil immersion, carefully and clean all areas that have come into contact with the oil.

January 16, 2013

BEWARE CLAIMS OF 2,000X MAGNIFICATION

False Magnification…. False Advertising or both? Be careful about buying a microscope that advertises 2,000x magnification. 2,000x is double the magnification for which standard light microscopes are designed so 2,000x must be too good to be true – as indeed it is!

Claims of 2,000x are achieved by the simple expedient of adding a set of 20x eyepieces to the standard 10x eyepieces. Magnification is achieved by multiplying the power of the objective lens by the power of the eyepieces. So 20x eyepieces x 100x objective lens = 2,000x total magnification, right?

Well, yes…..and no! Yes, the total magnification of the image increases, but the resolution of the image will degrade to the point where it is useless. This is because those higher power eyepieces push the total magnification above the Maximum Useful Magnification of the microscope. They higher power eyepieces create False or Empty Magnification. This is similar to when you try to zoom in on a slightly blurry pdf on a webpage. The image gets bigger but there is no improvement in resolution.

Maximum useful magnification is approximately equal to the size of the numerical aperture (N.A.) multiplied by 1,000. So, for a microscope with an NA of 1.25, the maximum useful magnification is approximately 1,250x. Anything above this maximum produces false magnification. The additional magnification yields no further useful information or finer resolution of detail. Quite the contrary. You will likely experience severe degradation in resolution. To quote Nikon, “In fact, excessive magnification introduces artifacts, diffraction boundaries and halos into the image that obscure specimen features and complicate the interpretation of visual interpretations”. In other words, the image gets blurry!

That is why all standard light compound microscopes are designed and sold with 10x eyepieces as standard and 100x objective lens as the largest obejective lens. At a 1,000x magnification, you do get higher magnification and improved resolution over, say, 400x, because the total power of magnification does not exceed the maximum useful magnification of the microscope.

Now, with some better quality microscopes you can get away with using 16x eyepieces. 1,600x is not such a stretch from 1,250x when using a microscope with NA 1.25. But 20x or 25x eyepieces? Not only will they not work efficiently but they are likely to frustrate your experience.

Those websites advertising 2000x magnification? False Magnification and false advertising in my opinion.