What’s in a rat?

The role of rodents in biomedical research is invaluable. Rodents, such as mice and rats, are the most commonly used mammals in biomedical research because of their anatomical, physiological and genetic similarities to humans. 

Scientists are able to genetically adapt mice to study a disease, for example by removing certain genes or by inserting (human) genes that are at the basis of certain disorders. For example, breast cancer can be simulated in mice to study the mechanisms of cancer and to test treatments. Mice and rats are also often used in behavioral studies to test, for example, treatments for memory loss in dementia.

Rodents are used in countless research areas, from cancer to immune diseases, heart disease, hypertension, metabolic and hormonal disorders, diabetes, obesity, osteoporosis, glaucoma, blindness, deafness, psychiatric disorders such as depression and schizophrenia, and neurodegenerative disorders such as Alzheimer's disease, Parkinson's and ALS.

The images taken with the new Moticam S6 camera show a cross-section with details through the upper body of the rat, just above the splice of the trachea into the two bronchi. The beautiful coup shows the various body parts in this cross section, some of which are indicated below.

With thanks to Cees Koopman, veterinarian.

© willemsmicroscope.com

Luminous wood

On the images you can see a cross section of a thin stem of Tilia showing the annual rings which are composed of Xylem in botanical terms or wood in daily language.

At the beginning of the growing season in a temperate climate, the Cambium will produce larger Xylem cells with thinner walls. These large cells (earlywood) are formed because the tree needs a lot of sap after winter. The earlywood is lighter and more porous. At the end of the growing season, the Cambium will produce narrower cells with thicker walls (latewood). Thus latewood contains more matter and is less porous, so it will look darker. Earlywood and latewood, which are formed during the same growing season, make up one annual ring. The most recent growth rings are situated at the tree's periphery, under the Cambium which is between the wood and the bark.

 

Toxic Taxus baccata

Taxus baccata has deep dark green needles all year round. It is an evergreen tree that is also often used as a hedge. In winter, Taxus bears red fruits that are much loved by birds, but very poisonous to ungulates.

Taxus baccata is usually a sturdy shrub that, if given space, can grow into a tree. Growth is slow but eventually the tree can reach a height of about 15 to 20 meters with a width of 12 to 15 meters. The species is widely used for hedges and also for topiary. Bulbs, cones, columns and even animal shapes are available. Taxus can tolerate very strong pruning, even down to the perennial wood.

Wood - a fascinating material

 INTRODUCTION

Wood is a wonderful material. It embodies the beauty and the odor of forests, the ecology of a natural building material and the microscopic aesthetics of a complex 3-dimensional anatomical structure.

The secondary cell wall of plants, constructed of parallel cellulose fibers embedded in an amorphous matrix is impregnated with lignin and minerals as a stabilizing factor for altitude records, e.g. the “Tall Tree”, 112 Meter height, a Sequoia tree from the California National Park. Shrubs and herbs use this principle to a lesser extent.

About tree dimensions. Look for the human. (Source)

For the increasing lack of sand and therefore of concrete as a construction material architects today tend to wood as an alternative. Asian engineers are famous for their buildings made with the help of a bamboo scaffold.

Hong Kong building with bamboo scaffold. (Source)

In Europe, architects are increasingly working with natural materials to follow the ecological demands of their customers. They reinvent proven technology with wood as a basis. From a wooden house to a wooden skyscraper: a big step.

The concept for Germany’s first high-rise building in Germany made of wood. (Source)

WOOD MICROSCOPIC VIEWS

All attributes of wood can be derived from a microscopic analysis. The odor of a Christmas tree (resin channels!), the characteristics of furniture wood, the mechanical stability of timber. A tree trunk with its 3-dimensional structure needs 3 cutting planes to be fully understood: a cross section, a tangential cut, a radial cut.

• THE CROSS SECTION

The cross section is most easy to understand: 

Typical for dicotyle plants

On the photos we see a cross section of the root of the Ranunculus. The specific arrangement of primary tissues shown here, is typical of dicotyle plants.