A personal collection of my favourite science-related articles, pictures, notes, etc. Enjoy :)
Something that’s been going on for a while now, obviously.
Work, moving, starting university, and other lovely and amazing things happening all at once don’t leave much time for keeping up with science news as much as I used to.
So, goodbye until whenever! I hope you all enjoyed your summer as much as I did :)
It may look like a handful of ribbons freshly lifted from a birthday present, but this week’s crystals in celebration of International Year of Crystallography are some more examples of molecular crystals: histamine and histamine receptors! The histamine receptor is a complicated set of proteins that are embedded in a cell membrane, and sometimes researchers crystallize histamines and their receptors to study them.Many will recognize that histamines sound a lot like antihistamines, which are medications you likely have taken for an allergic reaction. Histamines are what the body produces in response to allergens, such as ragweed pollen, which is considerably present at this time of year in much of the United States. And as beautiful as those ribbons are in the picture above, those are actually H1 receptors, not the histamine itself (as shown here). H1 receptors, one of four kinds of histamine receptors, are central to the histamines’ emergency response team. Whether it is asthma, hayfever, food allergies or mosquito bites, the body can go from itchy responses to snotty or stuffy noses to hives and finally anaphylaxis, which would result in death – all because it’s reacting to a foreign element.But histamines play other functions in the body. Histamines help the brain “wake up” and stay awake. They also help with neurotransmission and cell signaling, and even digestion. People on antihistamine medications find histamine levels decreased, which can contribute to the grogginess associated with those medications.Deciphering histamine receptor crystalline structures, by the way, is no easy task. In 2011, a Japanese crystallographer led a team of researchers to understand the H1 receptor’s crystalline structure better. The benefit is that it is exactly this kind of discovery that helps develop safer, more effective antihistamine drugs down the road.
This Extreme Antarctic Insect Has the Tiniest Genome
by Stephanie Pappas
The Antarctic midge is a simple insect: no wings, a slender black body and an adult life span of not much more than a week.
So perhaps it’s fitting the bug is now on record as the owner of the tiniest insect genome ever sequenced. At just 99 million base pairs of nucleotides (DNA’s building blocks), the midge’s genome is smaller than that of the body louse — and far more miniscule than the human genome, which has 3.2 billion base pairs.
(Though the midge’s genome still dwarfs the smallest of all genomes on record, which belongs to a bacterium that lives inside insects and contains just 160,000 base pairs.)…
(read more: Live Science)
photograph: Richard E. Lee, Jr.
Some of the most damaging brain diseases can be traced to irregular blood delivery in the brain. Now, Stanford chemists have employed lasers and carbon nanotubes to capture an unprecedented look at blood flowing through a living brain.
The technique was developed for mice but could one day be applied to humans, potentially providing vital information in the study of stroke and migraines, and perhaps even Alzheimer’s and Parkinson’s diseases. The work is described in the journal Nature Photonics.
Current procedures for exploring the brain in living animals face significant tradeoffs. Surgically removing part of the skull offers a clear view of activity at the cellular level. But the trauma can alter the function or activity of the brain or even stimulate an immune response. Meanwhile, non-invasive techniques such as CT scans or MRI visualize function best at the whole-organ level; they cannot visualize individual vessels or groups of neurons.
The first step of the new technique, called near infrared-IIa imaging, or NIR-IIa, calls for injecting water-soluble carbon nanotubes into a live mouse’s bloodstream. The researchers then shine a near-infrared laser over the rodent’s skull.
The light causes the specially designed nanotubes to fluoresce at wavelengths of 1,300-1,400 nanometers; this range represents a sweet spot for optimal penetration with very little light scattering. The fluorescing nanotubes can then be detected to visualize the blood vessels’ structure.
Amazingly, the technique allows scientists to view about three millimeters underneath the scalp and is fine enough to visualize blood coursing through single capillaries only a few microns across, said senior author Hongjie Dai, a professor of chemistry at Stanford. Furthermore, it does not appear to have any adverse affect on innate brain functions.
"The NIR-IIa light can pass through intact scalp skin and skull and penetrate millimeters into the brain, allowing us to see vasculature in an almost non-invasive way," said first author Guosong Hong, who conducted the research as a graduate student in Dai’s lab and is now a postdoctoral fellow at Harvard. "All we have to remove is some hair."
The technique could eventually be used in human clinical trials, Hong said, but will need to be tweaked. First, the light penetration depth needs to be increased to pass deep into the human brain. Second, injecting carbon nanotubes needs approval for clinical application; the scientists are currently investigating alternative fluorescent agents.
For now, though, the technique provides a new technique for studying human cerebral-vascular diseases, such as stroke and migraines, in animal models. Other research has shown that Alzheimer’s and Parkinson’s diseases might elicit – or be caused in part by – changes in blood flow to certain parts of the brain, Hong said, and NIR-IIa imaging might offer a means of better understanding the role of healthy vasculature in those diseases.
"We could also label different neuron types in the brain with bio-markers and use this to monitor how each neuron performs," Hong said. "Eventually, we might be able to use NIR-IIa to learn how each neuron functions inside of the brain."
The most common turtles kept as pets are Red-eared slider, Trachemys scripta elegans, map turtles, Graptemys spp, soft shell turtles, Apalone spp. & Trionyx spp, and others. This care guide applies to all of these but you should research your specific species to get detailed care instructions.
The average lifespan for a well cared for turtle varies but can be 30+ years.
It is a myth that turtles will only grow to the size of their enclosure, size is determined by genetics not by environment. Many aquatic turtle species can grow up to or exceed 12 inches and need very large aquariums. 1-2 hatchling sized turtles can be kept in a 30 gallon aquarium but they will soon outgrow it. A good rule of thumb is that for every inch of shell length you should provide 10 gallons of water. This means a single large female would need a 125 gallon aquarium. If you are unable to provide this you should look for a different reptile pet. Substrate can be bare bottom, sand, gravel, smooth river rocks. Be careful not to select rough substrates that could scrape turtle shells.
The best habitat for turtles is an appropriately sized outdoor pond with access to plenty of sun and areas of shade. If this cannot be provided an indoor aquarium is the next best.
Use a reptile safe water dechlorinator if you are using tap water. The tank should have enough water in it that the turtles can submerge completely and have plenty of swimming room.
It is vitally important to provide an area for turtles to climb out of the water and bask. This can be a large log, rock, floating platform, anything that offers enough room for all turtles to be out of the water.
A filter is also necessary because turtles produce lots of waste and will quickly dirty their water. A filter should have a filtration rate at least twice that of the size of your aquarium to ensure proper filtration. It is also important to perform 25% water changes weekly and change your filter media monthly.
Lighting & Heating
A submersible heater is required to keep the water between 75-80°F year round. Make sure to have an accurate thermometer so you can keep track of the water temperature. Fluorescent lights can be used above the aquarium but UV bulbs would be better as they provide both light and UV rays. A basking lamp should be hung over the basking area and it should provide UV as well as heat, the temperature should be about 90°F and all turtles should be able to bask at the same time if needed. This UV bulb should be replaced every 6 months to ensure adequate UV output.
The majority of aquatic turtles are omnivores and should be offered a varied diet. Quality turtle pellets can form the base of the diet but should not be overfed. Meaty foods that can be offered are earthworms, crickets, ;ish. Turtles should also be offered kale, escarole, greens, and other fresh vegetables. An adult turtle only needs to be fed 3-4 times a week. Any left over food should be removed from the water to prevent spoilage.
Signs Your Turtle is Sick
If you notice any of these signs bring your turtle to an experienced exotics veterinarian ASAP!
• Puffy eyes
• Nasal discharge
• Difficulty swimming
• Decreased appetite
• Pink coloration of shell/skin
Doxorubicin is a drug used in cancer chemotherapy. it works by intercalating DNA, with the most serious adverse effect being life-threatening heart damage. It is commonly used in the treatment of a wide range of cancers. Doxorubicin is commonly used to treat some leukemias and Hodgkin’s lymphoma, as well as cancers of the bladder, breast, stomach, lung, ovaries, thyroid, soft tissue sarcoma, multiple myeloma, and others. The most dangerous side effect of doxorubicin is cardiomyopathy, leading to congestive heart failure. The incidence of this cardiomyopathy is dependent on its cumulative dose. There are several ways in which doxorubicin is believed to cause cardiomyopathy, including oxidative stress, downregulation of genes for contractile proteins, and p53 mediated apoptosis.
Our Three (Brain) Mothers
Protecting our brain and central nervous system are the meninges, derived from the Greek term for “membrane”. You may have heard of meningitis - this is when the innermost layer of the meninges swells, often due to infection, and can cause nerve or brain damage, and sometimes death.
There are three meningeal layers: the dura mater, arachnoid mater, and pia mater. In Latin, “mater” means “mother”. The term comes from the enveloping nature of these membranes, but we later learned how apt it was, because of how protective and essential the meningeal layers are.
- The dura mater is the outermost and toughest membrane. Its name means “tough mother”.
The dura is most important for keeping cerebrospinal fluid where it belongs, and for allowing the safe transport of blood to and from the brain. This layer is also water-tight - if it weren’t, our cerebrospinal fluid (CSF) would leak out, and our central nervous system would have no cushion! Its leathery qualities mean that even when the skull is broken, more often than not, the dura (and the brain it encases) is not punctured.
- The arachnoid mater is the middle membrane. Its name means "spider-like mother", because of its web-like nature.
The arachnoid is attached directly to the deep side of the dura, and has small protrusions into the sinuses within the dura, which allows for CSF to return to the bloodstream and not become stagnant. It also has very fine, web-like projections downward, which attach to the pia mater. However, it doesn’t contact the pia mater in the same way as the dura: the CSF flows between the two meningeal layers, in the subarachnoid space. The major superficial blood vessels are on top of the arachnoid, and below the dura.
- Pia mater is the innermost membrane, which follows the folds (sulci) of the brain and spinal cord most closely. Its name means “tender mother”.
The pia is what makes sure the CSF stays between the meninges, and doesn’t just get absorbed into the brain or spinal cord. It also allows for new CSF from the ventricles to be shunted into the subarachnoid space, and provides pathways for blood vessels to nourish the brain. While the pia mater is very thin, it is water-tight, just like the dura mater. The pia is also the primary blood-brain barrier, making sure that no plasma proteins or organic molecules penetrate into the CSF.
Because of this barrier, medications which need to reach the brain or meninges must be administered directly into the CSF.
Anatomy: Practical and Surgical. Henry Gray, 1909.