Contradictiontonature - Sapere Aude

This illustrator’s new book is a clever introduction to women scientists through history.

During a dinnertime discussion two years ago, illustrator Rachel Ignotofsky and her friend started chewing on the subject of what’s become a meaty conversation in America: women’s representation in STEM fields.

Ignotofsky, who lives in Kansas City, Missouri, lamented that kids don’t seem to hear much about women scientists. “I just kept saying over and over and over again that we’re not taught the stories of these women when we’re in school,” she recalls. Eventually, it dawned on her: “I was saying it enough that I was like, you know, I’m just talking a lot about this; I should draw some of the women in science that I feel really excited about.”

Learn more here.

[Reprinted with permission from Women in Science Copyright ©2016 by Rachel Ignotofsky. Published by Ten Speed Press, an imprint of Penguin Random House LLC.]

The Portuguese man o’ war delivers a powerful sting to its prey—and sometimes to people—through venom-filled structures on its tentacles. It is not a jellyfish, but rather a colony of different types of zooids (small animals). Jean Louis Coutant engraved the plate for this illustration.

Brain Parasites: part II.

Taenia solium:

The pork tapeworm, Taenia solium, is the most harmful tapeworm in humans. Taenia solium infection is acquired either from human feces that contains Taenia solium eggs or from uncooked pork which contains larval cysts. If larvae are ingested, they mature into adults in the small intestine. This infection type is called taeniasis and is often asymptomatic. If eggs are ingested, the resulting disease is cysticercosis. It gets its name from larval Taenia solium called cysticercus. Both diseases are common in Africa, Asia, South America and Southern Europe. Taeniasis is rare in Muslim countries since people there do not consume pork.

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Most cones don’t really see color

We see color because of specialized light-sensing cells in our eyes called cones. One type, L-cones, sees the reds of strawberries and fire trucks; M-cones detect green leaves, and S-cones let us know the sky is blue. But vision scientists have now discovered that not all cones sense color (see video). The finding was made possible because, for the first time, scientists were able to look at individual photo-sensing cells.

The south side of Jupiter, observed by the Voyager 1 space probe on March 1, 1979.

Blood is red, urine is yellow, and faeces are brown. Why? Chemistry*!  *Disclaimer: shout-outs to biology and physics too.

(Image caption: The synapses of pyramid cells in the cerebral cortex form functional groups. Some of the related synapses are shown in green in the reconstruction. Credit: © MPI of Neurobiology / Scheuss)

Neurons form synapse clusters

The cerebral cortex resembles a vast switchboard. Countless lines carrying information about the environment, for example from the sensory organs, converge in the cerebral cortex. In order to direct the flow of data into meaningful pathways, the individual pyramidal cells of the cerebral cortex act like miniature switchboard operators. Each cell receives information from several thousand lines. If the signals make sense, the line is opened, and the information is relayed onward. Scientists at the Max Planck Institute of Neurobiology in Martinsried have now shown for the first time that contact points between specific neuron types are clustered in groups on the target neuron. It is probable that signals are coordinated with each other in this way to make them more “convincing”.

The cells of the cerebral cortex have a lot to do. They process various types of information depending on the area in which they are located. For example, signals from the retina arrive in the visual cortex, where, among other things, the motion of objects is detected. The pyramidal cells of the cerebral cortex receive information from other cells through thousands of contact points called synapses. Depending on where, how many and how often synapses are activated, the cell relays the signal onward – or not.

Information is passed on in the form of electrical signals. The neurobiologists were able to measure these signals at various contact points of the neuron. “The exciting thing is that the signals that a cell receives from, say, ten simultaneously active synapses can be greater than the sum of the signals from the ten individual synapses,” says Volker Scheuss, summarizing the basis of his recently published study. “However, until now it was unclear whether this phenomenon can be explained by a specific arrangement of synapses on pyramidal cells.”

By combining modern methods, the neurobiologists in Tobias Bonhoeffer’s Department have analysed the arrangement of synapses. They were able to selectively activate a specific type of pyramid cell in brain slices from mice using optogenetics. Thanks to simultaneous “calcium imaging”, they were then able to observe and record the activity of individual synapses under a two-photon microscope. In this way, they succeeded in showing for the first time how synapses are arranged with respect to each other.

The result of such synapse mapping analysed with a newly developed algorithm was clear: The synapses of pyramidal cells form clusters consisting of 4 to 14 synapses arranged within an area of less than 30 micrometres along the dendrite. “The existence of these clusters suggests that the synapses interact with each other to control the strength of the combined signal,” explains Onur Gökçe, author of the study. This is the first anatomical explanation for the disproportionate strength of clustered synapse signals in comparison to the individual signals – a finding known from activity measurements. The observation in layer 5 pyramidal cells was of particular interest, as the activity of these cells oscillates synchronously. “This rhythmic activity, which probably influences the processing of visual information, could synchronously activate synapse clusters, thus boosting the overall signal received,” says Scheuss.

Meet 5 of the most remarkable humans known to science

Would you rather have 10% of your brain, or no heart?

We might think we know the human body pretty well by now, but scientists are still discovering incredible individuals who are defying all odds by living out their lives with crucial parts missing, added, or tweaked in the most extraordinary ways.

From those with almost superhuman abilities, to others living without the organs we hold most dear, here are five of the most remarkable humans known to medicine.

Read more… 

Marrow Christmas and a Happy New Smear!

A very seasonal smear made from red marrow extracted from the iliac crest of a donor’s pelvis prior to transplantation.

Happy Holidays everyone

i♡histo

The image amazingly captures a single moment in time during the development of thousands of red and white blood cells.

Many of the small cells that are visible, like the ones forming the snowman’s carrot nose, do not have a nucleus. These are brand new erythrocytes (red blood cells) that are ready to exit the bone and enter the blood stream.

The other, slightly larger cells that have nuclei, like the snowman’s eyes and his top button, are either precursors to these erythrocytes (they will mature and lose their nucleus) or are precursors to the other blood cells in our body, the leukocytes (white blood cells): lymphocytes, monocytes, neutrophils, eosinophils and basophils.

In addition, the bone marrow is home to the cells that form platelets. These are huge multinucleated cells aptly named megakaryocytes - perhaps the cell at the bottom right.

It is possible to identify each mature cell and its precursor based upon its morphology and staining at higher magnification. High or low levels of these cells can indicate disease or cancers of the blood.

Life Continues Within the Body After Death, Evidence Shows

The body keeps working to repair itself after death, according to a provocative new study that could offer insight into how we might put the big sleep on hold.

Even after someone is declared dead, life continues in the body, suggests a surprising new study with important implications.

Gene expression — when information stored in DNA is converted into instructions for making proteinsor other molecules — actually increases in some cases after death, according to the new paper, which tracked postmortem activity and is published in the journal Open Biology.

“Not all cells are ‘dead’ when an organism dies,” senior author Peter Noble of the University of Washington and Alabama State University told Seeker. “Different cell types have different life spans, generation times and resilience to extreme stress.”  

In fact, some cells seem to fight to live after the organism has died.

“It is likely that some cells remain alive and are attempting to repair themselves, specifically stem cells,” Noble said.