Phase contrast - You always got a sample with you

Phase contrast is a widespread method in transmitted light microscopy. Especially in biology and medicine with their native samples this contrast method often is the easiest way to examine thin, unstained sections, smears and emulsions with almost no absorption.

The necessary hardware for Phase contrast 

• Figure 1: Objective with evaporated phase ring
• Figure 2: Illumination slot
• Figure 3: Centering telescope
• Figure 4: Phase ring

An objective with an evaporated Phase ring is combined with a respective illumination slot, placed in the focal plane of the condenser. The Centering telescope is a helpful tool to bring the round illumination ring to a perfect overlap with the partly transparent Phase ring. 

How to use the Phase Contrast accessories

Does this grow into a stink bug?

The Common green stinkbug or Palomena prasina is a common bug. You can find it in large parts of Europe, North Africa and the temperate parts of Asia. The bug has adapted to all kinds of biotopes such as forests, grasslands with suitable shrubs, marshes, gardens and parks, as long as food plants grow.

Allergic dermatitis in cats

When a cat comes into contact with an allergen, their body can react causing itching and inflammation. More severe cases of allergic dermatitis are easily recognized, while other may have very subtle signs and symptoms. That is why it is important to take a biopsy to make this sure and to investigate that it is not another ailment.

Are you sure you get the best image quality out of your microscope? About cleaning the front lens and using the aperture diaphragm.

No matter what microscope is in use, it should always be the intention of the user to optimize the image, means to get maximum information out of the sample. We are not talking about aesthetics, as some wrong microscope setup creates nice but misleading images, for example based on diffraction effects. From an educational model to a high-end outfit: experience shows that on any level of hardware and user knowledge mistakes are possible. Microscope experts are sometimes irritated when they walk through a hospital lab. Teaching correct microscope handling is simply not spirit of the time.

For an optimal image quality, the front lens of the microscope objective should be simply “clean”. No scratches, not grease, no residuals of immersion oil. This is not easy to achieve, as in daily work, especially with multiple users, a care for this aspect is not always in focus.

A nice example of a scratched/dirty front lens

What are blue-green algae?

Blue algae are cyanobacteria and live on light, carbon dioxide and nutrients dissolved in the water. Blue algae were the first organisms on earth and they produce oxygen. Many nutrients in the water can cause blue-green algae blooms.

The video and photo are showing these organisms present in a sample of water from a port in the southern Netherlands. The sample was taken shortly after exceptionally hot days with an outside air temperature of 40 degrees Celsius. With a blue-green algae bloom, the many blue-green algae on the water surface can come together and form a floating layer. Many types of blue-green algae make poisons. Contact with or swallowing blue-green algae can cause health problems.

Case of ovarian cavernous hemangioma

Case report

A 46 year-old woman without any pathological background except multiple uterine leiomyomas was undergone to a total hysterectomy and bilateral adnexectomy. During study of surgical specimen, a little reddish nodule of 9 mm was discovered in the hilum of the left ovary. 

Microscopically, this nodule was made of dilated thin-walled vascular channels, filled of blood.

Image taken with a Moticam X3

Lick granuloma dog

A lick granuloma or acral lick dermatitis is a place on the skin as a result of frequent licking by the dog and is found usually at the end of the paws, hence acral (think of the Athenian Acropolis: city on top) Lesion is sharply defined. This is a nasty ailment. It is not always clear what causes it, but itching is often the reason. A physical cause is rarely found. Usually the cause is psychological such as boredom, separation anxiety, stress, nervousness or attention seeking behavior. Licking is then a distraction for the dog. Once the dog is licking, it is difficult to stop this. It has become a habit for the dog.

The first symptoms are discoloration of the coat due to the saliva. The skin can become thicker and bald. Inflammation of the skin is possible due to the granuloma. This starts itching more and makes the dog more lick and bite. Then the dog comes in a vicious circle. The process can continue down to the bone, sometimes amputation is necessary. A lick granuloma actually only occurs on the front legs.

Primitive, but unique

Ferns are perhaps very old plants, but they are unique in their kind. They already occur in several hundred million year old fossils. After all, it was the first plant with roots and a real vascular system. In this way the ferns managed to extract water from the ground and use it for their further development. Because of the branches of the vessels it was also possible to get the water into the tops of the feathers or leaves. Ferns do not carry flowers. They therefore do not propagate with seeds, caused by fertilization of pistils with pollen through bees, beetles, birds, wind or otherwise. 

Honey - Try to find out its origin

Honey is one of the oldest food products. Cave paintings from the stone age give witness of how the product of wild bees has been used as the first sweetener, containing lots of positive ingredients for a general healing effect.

Nowadays honey is part of the food industry with its profit orientated mechanisms. Price is an issue, and the cold hurled product needs careful attention and efforts for maximum quality.

The origin of a product in general is essential for tracing the manufacturing steps. Latest since BIO became a quality issue in food industry, foodstuff testing laboratories are looking for hints to find out the nectar and honeydew sources which are the basis of honey. Pollen residuals within the honey give a clear indication about the region of origin. In Europe, honey from Central America is widespread, but not always clearly indicated. Eastern Europe and China are playing an important role as honey producers.

Once the pollen is detected and allocated to a defined plant species, it is easy to debunk imposters. Pollen from tropic plants found in a honey sample declared as a Central European product – a microscope will be the necessary tool to find out. Brightfield illumination is the required method, Phase contrast is not optimal as the pollen grains clearly have a significant 3D dimension, too thick for applying this contrast method. Simple POL contrast may help to find the isolated pollen grains within the honey sample.

Some examples from the Middle European flora:

Leontodon spec.

It hides in moss and lichen

When studying moss and lichen under the microscope, you will discover that in addition to the beautiful pictures it produces, a lot of animal life crawls around in it. If you walk through nature and see the many types of moss and lichen, you actually do not realize that. This is perhaps due to the fact that the animals are hardly visible to the naked eye.