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Johnathan Chung
Per Scientiam Progredimur
Per Scientiam Progredimur

Johnathan's posts

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Testing New Technologies for Future Use in Space
Astronauts and Google Glass

Along with my last post (, some of Samantha Cristoforetti's fellow astronaut colleagues are currently on a SEATEST mission at Aquarius -- one of the few underwater research laboratories in the world.

Google Glass makes an appearance in the video :)
The SEATEST mission is also an opportunity to test new technologies for future use in space. Just-in-time training delivered through head-up displays can significantly decrease crew training time and optimise work efficiency onboard the International Space Station and improved exercise devices can improve astronaut health.

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Training for covert +Ingress operations in space! :P

Samantha is the 1st Italian woman astronaut and the 3rd woman astronaut of the European Space Agency. She is scheduled for Expedition 42/43 to the International Space Station (ISS) in 2014.

She maintains a fun logbook on Google+ of her daily training and activities. L-number is the approximate countdown in days to launch. I've been reading along since L-500, and it's totally worth browsing through her profile to catch up on all her previous entries.

Former classmate Luca Parmitano also continues to post stunning photos to Google+ from on board the ISS:
L-439: Logbook

I have picked up ATV training with crewmate Sasha today.

One of the classes dealt with the operations related to ingressing ATV after docking. Sounds easy enough, but ingress operations actually take several hours.

For one thing, before opening any hatch you need to make sure that you have a good seal between Station and the vehicle itself. We call these type of procedures leak checks: you basically create a pressure differential between two volumes that are sealed off and check that the pressure equalization across the seal over a certain time is within the limits.

Once the leak check is passed and you open the hatch, it's time to take a long series of air samples, part for return to ground and part to test onboard for different contaminants.

Then you need to install an air filter and let it fully clean the ATV atmosphere for many hours. Only after the filtering is complete are you allowed to enter ATV without protective mask and goggles. If you think about it, it makes sense: on Earth, small particles fall to the ground, but in space they float, so they can easily get into your eyes or your lungs. Of course, we don't expect that on space vehicles, which are prepared in clean rooms, but better be safe than sorry!

You can see in the picture a crewmember entering ATV with protective gear. And what are those yellow things? Those are clamps that are installed on the hatch to increase the mechanic rigidity of the link between ATV and Station. After all, an ATV is a much bigger beast than a Progress or a Soyuz!

Those clamps are pretty interesting. Since you need to be able to close a hatch quickly in an emergency, they are designed so that you just need to pull on the string of one and they all come off. Just make sure you don't have your fingers in the way when the spring loaded lever snaps to the release position!


Traduzione italiana a cura di +AstronautiNEWS  qui:

En español aquí:

Building a Better Future
Smarter, Cleaner, Healthier

In the past week, Google has announced some great partnerships and initiatives to help broaden access to education, continue to support green technologies, and begin to tackle health issues regarding aging and illness.

• Contributor to Open edX, MOOC open-source education platform:

• Official Internet Technology partner of Solar Impulse, a solar-powered airplane that can fly day and night -- "Around the World in 2015":

Calico (California Life Company), a new company addressing aging and associated diseases through moonshot thinking around healthcare and biotechnology:

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Exploring Space: Cosmic Revolutionaries

Transience is the lapidary of the human race, shaping us through perceived moments of awe and beauty by touting each experience as unique -- a limited time offer by the Universe teasing us with the idea that in the 13.7 billion years of its existence, we have emerged at the forefront to witness its presence and unravel its significance.

Yet, it doesn't matter what we know or don't know about it; it is there. We assign that meaning for ourselves. The more we explore and learn about outer worlds, the more we define or displace our role among them. A desire to explore is a fundamental desire to know who we are, to persist beyond a fading memory.

We don't climb Mount Everest because it is there; we climb it to know we are there. To know we can. To protest impermanence by achieving something greater than ourselves. To create a legacy lasting beyond our time.

So who will be our collective witness before our time expires? Perhaps no one. And in the blink of an eye, the Universe will move on.
Watch my latest video! Existential Bummer! 

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Blood Group Types
Compatibility and Transfusions

This write-up was prompted by a related post asking about blood group compatibility:

| Types of Blood Products |
| ABO & Rh Groups |
- Universal recipient
- Universal donor
| Blood Antigen Markers |
- Determining ABO designation: H antigen derivatives
| Minor Blood Groups |
| Transfusion Preparation |
- Type & screen
- Type & cross-match
- Emergency cases

Common Blood Products

Whole, 2%, and skim (kidding)...

Whole blood used to be given for rapid and massive blood loss up until specific components were determined to be as clinically effective and more efficient in terms of supply management. Some components include packed red blood cells (pRBCs), fresh frozen plasma (FFP, which contains clotting factors), a more concentrated version of thawed and centrifuged FFP called cryoprecipitate, platelets, and others.

Separation permits judicious use of blood components, such as selective treatment using only pRBCs while conserving platelets to be used in a different patient, for example. It also allows different components to be packaged and stored under different conditions to maximize shelf-life.

ABO and Rh Factor

Antigens are any cell fragment or molecule that antibodies can attach to and "flag" for eventual destruction by the immune system.

Major ABO and Rh blood group systems are highly emphasized because their antigens are the most immunogenic and pose a significant risk in terms of potential incompatible blood transfusion reactions.

AB blood type is the rarest and often cited as the "universal recipient" because those people lack antibodies targeted against A and B blood group antigens. In other words, A and B are not perceived as "foreign", and those individuals can handle all types (A, B, and O).

Blood type O is often considered the "universal donor" because those red blood cells do not have the potentially immunoreactive A and B antigens on them. Blood group O is the most common phenotype in the population at around 36-49% depending on race and ancestral place of origin.

Rh is named after the Rhesus monkey, and Rh factor commonly refers to the D antigen only even though there are around 50 antigens in the Rh group (this comes up often in obstetrics and pregnancy evaluation because of the transfer of blood between the mother and fetus). The presence or absence of the D antigen is the plus or minus designation seen after A, B, O, or AB (e.g., O+ or "O positive" is Rh positive O blood).

Similar But Distinct Blood Antigen Markers

In normal scenarios, the O, A, and B antigens expressed on the surface of different RBCs are determined by 3 alleles located on chromosome 9. All antigens actually contain the same fundamental chain or base unit called the H antigen, and each varies by only one molecule.

If that oligosaccharide (short chain of carbohydrates) anchored to a protein on the RBC is unmodified, it is classified as "O" blood.

The "A" allele responsible for encoding a certain enzyme will add a molecule called N-acetylgalactosamine to transform the "O" chain (basic H antigen) into an "A" antigen instead. If the enzyme encoded by the "B" allele appends galactose (yes, the same natural sugar commonly found in milk), the "O" chain then becomes a "B" antigen. Basic ABO antigen structures are illustrated in Figure 11.17 here

Minor Blood Groups

In reality, aside from ABO and Rh, there are many minor blood group antigens too. There are 30 other blood group systems, each of which has several sub-types. Of the minor groups, some of the more memorable ones are named after the patients whom they were first discovered in, such as Kell, Kidd, Duffy, Lewis, etc. It is thought that some minor blood groups may have arose due to evolutionary advantages. For example, some people lacking the Duffy antigen demonstrate resistance to certain species of malaria.

Relatively fewer people deal with these details on a day-to-day basis or are expected to remember the exact specifics, such as pathologists and technicians who work in the blood bank of a hospital. Nonetheless, these lesser-known minor antigens exist and are important.

• More info from Blood Groups and Red Cell Antigens:
• A list of blood groups:

What the Doctor Ordered: Type, Screen, and Cross-match

In medicine, there are a couple ways to order blood to prepare for transfusions. For routine elective surgical procedures (i.e., planned, not an emergency) where minimal blood loss is expected, doctors can order a "type and screen". This means they identify the major type of blood group of the patient and screen for clinically significant antibodies in the recipient's serum. This is done out of precaution and gives a heads-up to the blood bank to let them know the blood may be required, but is not anticipated to be needed. It's also a preliminary and less intensive way to analyze blood because IF no unexpected RBC antibodies are present in the patient, then the extremely detailed identification of possibly hundreds of minor antigens in donor blood is not necessary. For those who qualify, blood can be given based on just ABO and Rh typing.

In other cases where blood products will be definitely administered (e.g., symptomatic anemia or active uncontrolled but slow bleeding), doctors request a "type and cross". The typing identifies the major blood group as before, and the full "cross-matching" goes into much deeper analysis to match up donor and recipient for all the clinically relevant minor antigens.

Of note, the addition of a cross-match to a "type and screen" (ABO/Rh typing and antibody screening) increases detection of incompatibility by only 0.01%. However, since millions of transfusions are performed, that 0.01% is not necessarily insignificant.

In the Case of an Emergency

In urgent situations (e.g., hemorrhagic shock) where the correct ABO type is in doubt or unknown and the doctor cannot wait for a full cross-match, O- (O Rh-negative) blood is given. In life-threatening emergencies where Rh-negative blood is unavailable, giving Rh positive blood is not off limits (the apparent reaction can be medically managed in other ways, whereas the immediate life-threatening cause can only be managed with a few options).

A "type and screen" can take up to ~10 minutes, and a "type and cross-match" could take on the order of an hour. If they don't have 60 or even 10 minutes to spare, they start to administer the "universal donor" blood up front (while continuing to cross-match). This scenario does not happen as often, though, and is more likely to occur during disaster response situations or accidents involving severe injuries.

• Facts about blood use and donations:
• Mosquitoes may tend to prefer blood type O:

#ScienceEveryday   #BloodType   #Transfusions  

Public Domain image from Wikipedia.

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As Elon Musk mentioned on his Twitter account recently, here is the video of how he envisions technology enhancing the future of design. He is able to virtually manipulate wire-frame and 3D-model images to design rocket parts using hand gestures and then visualize the process on different displays, including experimentation with an Oculus Rift virtual reality headset. The product can then be made with titanium through additive manufacturing (i.e., using a 3D metal printer). Awesome!
At SpaceX, we love to play with cutting-edge tech. Our latest concept: natural gesture-based interaction with a computer-aided design program. Watch the video here:

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The Shape of the Universe
For Earthlings 101

+Brian Koberlein described how the universe could be flat and finite in volume, but without an edge:

The alien Zogg from Betelgeuse explores these concepts further in a simple and entertaining animation with great visualizations.

He (it?) distinguishes between topology and geometry and shows several models that could fit the flat, finite, faux edge form :)

References are made to +Hank Green of +vlogbrothers and +Derek Muller of +Veritasium, along with a fun twist on the Nerdfighteria DFTBA motto: "Don't forget to be awesome."

Related: How Do We Know the Universe is Flat? by +Deep Astronomy.

#ScienceEveryday   #Universe   #Topology   #Space

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A Peek at Silica Valley
Geological formation of quartzite pillars and caves

What Do You See?

I really like the #ISeeTheWorldWithScience  series started by the Science on Google+ Community. Take or select a photo and create an interesting or unique caption based on any underlying science concepts directly related to the picture. The possibilities are endless, and it's a fun way for curious people to learn something new!

Note that your contribution doesn't have to be detailed or complex (that's just my own preference) and can be a quick & simple observation. So click through to the original for more challenges and tidbits, and check out past ISTWWS posts as well:

Rock Formation and Breakdown

The primary type of rock seen in the original post below is quartzite and was created by tectonic compression of quartz sandstone [1]. The pillars probably formed mostly by erosion. Ice forming within cracks, plant growth, and rain contributed to fracturing and destruction over millions of years.

Karst development [2] is a type of geological formation where layers of rock are dissolved. Karst is more common for soluble limestone bedrock, but apparently can happen with quartzite under very specific conditions. Generally, quartzite tends to be one of the more highly resistant minerals and rocks to weathering.

Quartzite in Water

At the molecular level, quartz can be hydrated to form silicic acid: 
SiO2 (s) + 2 H2O (aq) = H4SiO4 (aq)

The extremely slow dissolving rate is due to bond breaking and hydration of silica (SiO2) at the surface. Silicic acid (H4SiO4) is very weakly acidic and a minor contributor to the more dominant mechanical weathering process because silicic acid barely ionically dissociates under normal karst conditions.

Cave Formation: Speleogenesis

This karst dissolving process actually becomes a main factor in the formation of quartzite caves [3], which could be near the location depicted in the photo (once again, click through to the original post). They are relatively rarer, though, compared to limestone or dolomite caves [4].

Side note: limestone is made of calcite, which is calcium carbonate or CaCO3. Dolomite is calcium magnesium carbonate, or CaMg(CO3)2. Over 80% calcite content is one factor that tends to favor karst conditions [5].

Disillusioned with Dissolution

If you're anticipating watching this quartzite chemical reaction in action, don't hold your breath. Saying quartzite karst is slower than molasses in January is quite an understatement. (That's two colloquialisms in one paragraph for you!)

In the laboratory setting, an estimate of the rate of quartz dissolution by water at 25°C is 10^(-17) moles per second for each cm^2 surface area [3]. In these isolated conditions, that turns out to be 0.02 micrograms dissolved per squared centimeter of surface exposure over one year (I told you it was slow).

In nature, however, organic acids from dense vegetation in quartzite terrain increase this rate substantially. Microbes in the soil also contribute by releasing (smelly) hydrogen sulfide gas, which turns into hydrosulfuric acid. Hydrothermal conditions from deeper layers can increase the temperature to several hundred degrees Celsius and speed up the reaction too.

In summary, quartzite rock morphology above ground is more likely influenced by mechanical erosion through weathering, while underground changes are due to chemical dissolution and corrosion.

Photo Location

The photo linked to in the original post appears to have been taken somewhere within Zhangjiajie National Forest Park in China [6] and possibly within a smaller popular historic area called Wulingyuan [7]. The UNESCO World Heritage site has some more great information on plants and endangered species found in that area [8].


I recommend reading reference #4 as an interesting and well-written introduction to the factors involved with the science of cave formation.

[1] Quartzite -
[2] Karst -
[3] Encyclopedia of Caves and Karst Science, p. 622 -
[4] How Caves Form by Eniscuola Energy and Environment -
[5] Cave Formation by University of Wisconsin Eau Claire -
[6] Zhangjiajie National Forest Park -
[7] Wulingyuan -
[8] UNESCO Wulingyuan Scenic and Historic Interest Area -

#ScienceEveryday   #Quartzite   #Caves   #Karst   #Geology  

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Lead in Lipstick: The Whole Picture
An Example Analysis Emphasizing Perspective and Context

The cluster of studies from 2007-2012 on lead in lipstick has been used as an example in some biostatistics classes to highlight how easy it is to misinterpret data. Reports by the media are sometimes misleading, but (to be fair) not necessarily erroneous or intentionally so because they are looking at real and true numbers, just not in the appropriate context. Delving deeper, we can take a look at individual study details to analyze to what degree a particular claim has merit.

Of note, this specific article presents conclusions in a mostly balanced and reasonable manner. In the recent past, there was an inaccurate portrayal of this specific topic in the news that got people riled up, and you can imagine it spurred unwarranted public fear. I'm linking to this article because it's a more recent write-up that digs up previously cited numbers on lead content as a platform to discuss other trace metals we aren't keeping as good track of (to which I agree the latter probably needs to be studied more and that we should not become complacent). But for educational purposes, we're going to focus the discussion on lead content because that has been studied extensively.

The Main Concern

The 2007 headlines at the time read, "One-third of lipsticks on the market contain high lead". The authors looked at 33 lipsticks and classified lead content levels as high or excessive with respect to the FDA 0.1 parts per million (ppm) limit set for candy. In 2009, the FDA did a follow-up study (n = 22) and subsequently repeated the same type of study in 2012 using a larger sample of n = 400 shades of lipstick.

In the follow-up studies, they used an extremely sensitive method of lead detection -- so sensitive that they also detected types of lead that aren't absorbed by the body. That's not a downside, but just something to keep in mind when interpreting results in an overly conservative context. Since there are unavoidable natural trace amounts of lead in many things, the question is not "IS there any lead in lipstick?" but rather how much lead is there, does it have a clinically meaningful impact, and should women be worried?

A Closer Look

2012 data (n = 400) and 2009 data (n = 22) showed a mean (SD, standard deviation) concentration of lead in lipstick of 1.11 ppm (0.97) and 1.07 ppm (0.96), respectively. The median values of 0.89 and 0.73 ppm are more representative of the "typical" concentrations because the median is less affected by extreme values in a data set. The distribution of data was right-skewed, so infrequent occurrences of higher concentrations at the 99th percentile (and max value) were 4.91 ppm (7.19) and 3.06 ppm (3.06). [Data tables: ] Notice the 2012 max value (which is 4 standard deviations above the mean) is higher than that from 2009, but that's due to inclusion of more 'outliers' in a larger sample size and not due to an actual increase in lead content (we know this because most of the other numbers -- mean, median, SD, interquartile range, and individual percentile values -- remained similar to 2009 with the exception of the upper bound).

Quantifying or Estimating Lipstick Use

Next, to get an idea of the potential "real world" impact and translate these numbers into practice, there was a European study in 2007 in Food and Chemical Toxicology that quantified consumer exposure to lead in lipstick (in other words, how much lipstick were people actually using?)

The very highest application of lipstick (once again, right-skewed data) was 218 mg / day used by 1 in 30,000 women. Keep in mind 218 mg was NINE standard deviations above the mean and approximately 5.5% of a whole tube of lipstick (meaning an entire 4-gram tube would be used in 18 days). As a comparison, median usage was a modest 17.1 mg / day.

Extent of Lead Exposure is Very Small

Not all lipstick that is applied will be consumed or absorbed; some will be rubbed off or removed by a drinking glass, tissue, make-up removal kit, etc. If we assume a very generous proportion like 50%, in the very highest concentration of lipstick used by the most generous of applicators, 7.19 microgram/gram * 218 mg * 1g/1000mg * 0.5 = 0.78 micrograms of lead exposure per day. The "typical" exposure of 0.0076 mcg calculated from the median values is 100 times less (mcg/g is the same as ppm and used for unit conversions in case that threw anyone off. Also note the abbreviation of micrograms (mcg) is not to be confused with milligrams (mg)).

This maximum exposure (the very upper limit) scenario applies to roughly 1/30,000 * 1/400 = 1 in 12 million women. Additionally, the FDA "provisional tolerable daily intake" of lead from all sources is 75 mcg/day, of which 0.78 mcg from lipstick is still only 1% (for that rare 1 in 12 million person) and a measly 0.02% for the more common typical person.

What Does This Mean?

Numbers are interesting, but usually people need a comparison to relate to.

For perspective, the average American consumes 1-4 mcg / day (1.3% - 5.3% of the daily tolerable limit) of lead from food alone. Typical daily lead exposure from chocolate for the average American is up to 29 times that of the typical daily exposure from lipstick. That's not saying there is a lot of lead in food; that's saying there is a miniscule amount of lead exposure from lipstick.

Amount of lipstick applied, absorption and bioavailability of lead, and potential clinical effect is a much different story than only looking at isolated absolute concentrations by themselves. Much of the difference arises from the fact that 100% of food or candy is intended for consumption, whereas 100% of lipstick is not eaten. And even after taking that into account, candy (chocolate, anyway) is still far beyond the estimated realistic maximum lead exposure people get from lipstick.

One caveat is that if children are starting to use large amounts of lipstick, their weight, size, and developmental characteristics as compared to adults are different and may need to be looked at separately. Of course, lead intake should be minimized as there is no "healthy" amount, but of all things to pick on or divert attention and resources to, lipstick is not an important source in the grand scheme of things.

#ScienceEveryday   #PublicHealth   #Statistics   #Lipstick   #Lead  

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Another milestone for SpaceX's 10-story "Grasshopper" vertical takeoff, vertical landing vehicle!

In June, their VTVL rocket test reached an altitude of 325 meters:

Now they've demonstrated more aggressive steering maneuvers with lateral movement, in addition to the vertical stabilization, hovering, and descent, which is always fun to watch :D

You can test and compare your own landing skills here ;) :P!/arcade/lunarlander/play
Yesterday, Grasshopper completed its first ever lateral divert test, flying to a 250m altitude with a 100m lateral maneuver before returning to the center of the pad. Aggressive steering maneuvers like this will be an important part of landing the rocket precisely back at the launch site after reentering from space at hypersonic velocity.
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