Metal-ion

1,000 Days in Orbit: MAVEN’s Top 10 Discoveries at Mars

On June 17, our MAVEN (Mars Atmosphere and Volatile Evolution Mission) will celebrate 1,000 Earth days in orbit around the Red Planet.

Since its launch in November 2013 and its orbit insertion in September 2014, MAVEN has been exploring the upper atmosphere of Mars. MAVEN is bringing insight to how the sun stripped Mars of most of its atmosphere, turning a planet once possibly habitable to microbial life into a barren desert world.

Here’s a countdown of the top 10 discoveries from the mission so far:

10. Unprecedented Ultraviolet View of Mars

Revealing dynamic, previously invisible behavior, MAVEN was able to show the ultraviolet glow from the Martian atmosphere in unprecedented detail. Nightside images showed ultraviolet “nightglow” emission from nitric oxide. Nightglow is a common planetary phenomenon in which the sky faintly glows even in the complete absence of eternal light.

9. Key Features on the Loss of Atmosphere

Some particles from the solar wind are able to penetrate unexpectedly deep into the upper atmosphere, rather than being diverted around the planet by the Martian ionosphere. This penetration is allowed by chemical reactions in the ionosphere that turn the charged particles of the solar wind into neutral atoms that are then able to penetrate deeply.

8. Metal Ions

MAVEN made the first direct observations of a layer of metal ions in the Martian ionosphere, resulting from incoming interplanetary dust hitting the atmosphere. This layer is always present, but was enhanced dramatically by the close passage to Mars of Comet Siding Spring in October 2014.

7. Two New Types of Aurora

MAVEN has identified two new types of aurora, termed “diffuse” and “proton” aurora. Unlike how we think of most aurorae on Earth, these aurorae are unrelated to either a global or local magnetic field.

6. Cause of the Aurorae

These aurorae are caused by an influx of particles from the sun ejected by different types of solar storms. When particles from these storms hit the Martian atmosphere, they can also increase the rate of loss of gas to space, by a factor of ten or more.

5. Complex Interactions with Solar Wind

The interactions between the solar wind and the planet are unexpectedly complex. This results due to the lack of an intrinsic Martian magnetic field and the occurrence of small regions of magnetized crust that can affect the incoming solar wind on local and regional scales. The magnetosphere that results from the interactions varies on short timescales and is remarkably “lumpy” as a result.

4. Seasonal Hydrogen

After investigating the upper atmosphere of the Red Planet for a full Martian year, MAVEN determined that the escaping water does not always go gently into space. The spacecraft observed the full seasonal variation of hydrogen in the upper atmosphere, confirming that it varies by a factor of 10 throughout the year. The escape rate peaked when Mars was at its closest point to the sun and dropped off when the planet was farthest from the sun.

3. Gas Lost to Space

MAVEN has used measurements of the isotopes in the upper atmosphere (atoms of the same composition but having different mass) to determine how much gas has been lost through time. These measurements suggest that 2/3 or more of the gas has been lost to space.

2. Speed of Solar Wind Stripping Martian Atmosphere

MAVEN has measured the rate at which the sun and the solar wind are stripping gas from the top of the atmosphere to space today, along with details of the removal process. Extrapolation of the loss rates into the ancient past – when the solar ultraviolet light and the solar wind were more intense – indicates that large amounts of gas have been lost to space through time.

1. Martian Atmosphere Lost to Space

The Mars atmosphere has been stripped away by the sun and the solar wind over time, changing the climate from a warmer and wetter environment early in history to the cold, dry climate that we see today.

Maven will continue its observations and is now observing a second Martian year, looking at the ways that the seasonal cycles and the solar cycle affect the system.

For more information about MAVEN, visit: www.nasa.gov/maven

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Molecule of the Day: Ammonia

Ammonia (NH3) is a binary compound of nitrogen and hydrogen. Commonly found in nature, it exists as a pungent, colourless gas under standard conditions, but is often sold as a solution in water. It is one of the most widely produced chemicals in the world, with 146 million tonnes being produced in 2016 alone.

Ammonia is a weak base, with a pKb of 4.75; it can reversibly react with water to produce ammonium and hydroxide ions.

NH3 + H2O ⇌ NH4+ + OH-

Due to the equilibrium shown above, solutions containing ammonia and ammonium ions are commonly used as buffer solutions, which resist pH changes upon addition of small amounts of acids or bases.

At the same time, ammonia can also act as an acid with very strong bases and reactive metals. For example, sodium metal reacts with ammonia to produce sodium amide, a strong base:

2 Na + 2 NH3 → 2 NaNH2 + H2

With its lone pair, ammonia can also coordinate to metal ions, resulting in colourful metal ion complexes, such as the deep blue tetraamminecopper(II) ion:

Ammonia is a versatile starting block for many chemical and fertiliser industries, as it offers a convenient way to introduce a nitrogen atom into a molecule. Being a nucleophile, it can participate in nucleophilic substitution and addition-elimination reactions, a useful trait that is exploited in many chemical syntheses. For example, the first step in the Strecker amino acid synthesis, which allowed chemists to synthesise amino acids for the first time instead of extracting it from organic material, involves the usage of ammonia to convert an aldehyde into an imine.

Ammonia is industrially produced by the Haber process, in which nitrogen is reacted with hydrogen under moderate temperature and high pressure in the presence of a catalyst to produce ammonia according to the following equation:

N2 + 3 H2 ⇌ 2 NH3

As the reaction is reversible, the reaction mixture is then cooled to condense the ammonia, and the leftover hydrogen and nitrogen is pumped back into the reactor to participate in the reaction again, thus maximising yield.

Ammonia is a metabolic waste from the digestion of proteins and other nitrogen-containing products, and is excreted through the urine. It is also produced from the decomposition of tissues.

While ammonia is present in many tissues, it is metabolised into urea rapidly in the liver via the urea cycle, as urea is much less toxic and basic, and the buildup of ammonia can result in liver cirrhosis.

Anti-cancer drugs - DNA targeting

Include alkylating agents, intercalating agents, and chain cutters.

Alkylating agents

  • Highly electrophilic species, looking for nucleophilic sites to attack, and forming covalent bonds to bases in DNA 
  • Prevent replication and transcription 
  • Toxic side effects (e.g. alkylation of proteins) 
  • Bind in the major groove of DNA
  • Both types cross-link DNA by covalently bonding to nitrogen of base pairs.
  • Binding of nucleic acid bases results in miscoding and distortion. 
  • Distortion of DNA prevents excision by HMG proteinspermanent damage. 
  • Transcription and replication prevented, tumour growth slows. 

Two electrophilic sites on an anticancer drug can cause interstrand and intrastrand cross-linking.

  • Preference for 1,2-GG or 1,2-GC linkage sites, with interstrand or intrastrand linkage, is dictated by drug chemical structure 
  • Other linkage adducts are possible. Eg 1,3-GCG, 1,2-GA. 
  • Monofunctional adducts are also possible 

Chlormethine (a nitrogen mustard)

  •  Chlormethine is highly reactive, toxic side effects. 
  • Lead compound for many less toxic mustard derivatives. 
  • Methyl (CH3 ) group has positive inductive effect – promotes loss of chloride – see mechanism 

Less toxic chlormethine analogues:

  • Melphalan:  e- withdrawing ring lowers Nu strength of N, less reactive drug, less side effects, less toxic. Mimics PhAla, carried into cells by transport proteins. 
  • Uracil mustard:  Uracil ring is e-withdrawing, less reactive alkylating agent. Mimics a nucleic acid base, concentrates in fast growing cells.
  • Cyclophosphamide:  Most commonly used alkylating agent, Non-toxic, orally active prodrug. Acrolein associated with toxicity.
  • Busulfan: Causes interstrand cross-linking. Sulphonate group withdraws electrons, adjacent carbon subject to Nu attack by DNA bases. 
  • Dacarbazine – A diazine:  Prodrug activated by oxidation in liver, decomposes to form methyldiazonium ion. Alkylates guanine groups 

INTERCALATING AGENTS

 Aminoacridines eg Proflavine

Antibiotics - Dactinomycin

  • Extra binding to sugar phosphate backbone by cyclic peptide 
  • Intercalates via minor groove of DNA double helix 
  • Prevents unwinding of DNA double helix 
  • Blocks transcription, blocks DNA-dependent RNA polymerase 

Anthracyclines eg Doxorubicin (adriamycin) 

  •  Extra binding to sugar phosphate backbone by NH3 Planar rings and Anthracyclines eg Doxorubicin (adriamycin) 
  • Intercalates via major groove of DNA double helix 
  •  A topoisomerase poison - blocks action of topoisomerase II by stabilising DNA-enzyme complex 

CHAIN CUTTERS 

Calicheamicin g1 I antitumour agent 

  •  Nucleophilic attack on trisulphide chain starts a rearrangement process. 
  • This interacts with DNA to generate a DNA diradical, which reacts with oxygen, resulting in chain cutting.

Bleomycins (BLM)

  • Highly active head, neck, testicular cancer (Hodgkin lymphoma) 
  • Single and double-strand cleavage of DNA with several reduced metal ions and O2 , Fe(II) highest in vivo activity. 
  • Three regions - 
  • bithiazole DNA binding domain (DBD) locks BLM into the minor groove, 
  • carbohydrate domain (CHD) H-bonds BLM to sugar phosphate of DNA 
  • metal binding domain (MBD) bonds to Fe(II)    

Mechanism

  • A reaction with hydrogen peroxide gives Fe(III) and hydroxyl radicals which abstract H atoms and cut the DNA chain. 
  • Fe2+ + H2O2 Fe3+ + OH. + OH− Fenton mechanism 

Lungs and skin have low levels of BLM hydrolase - higher sensitivity and toxicity. Pneumonitis occurs in about 10% of patients, progresses to pulmonary fibrosis. Over-expressed in malignant cells, resistance to bleomycin    

Summary of Anti-Tumour Specificity for DNA 

Major groove alkylators 

  • GG interstrand - N-mustards, nitrosoureas. 
  • GG intrastrand - methanesulphonates. 
  • GC-interstrand - nitrosoureas, triazines. 

Minor groove intercalators 

  • GG interstrand – anthracyclines. 
  • GC-interstrand – actinomycins, acridines. 

Minor groove chain cutters 

  • GC or GT intrastrand – bleomycins 

In chemistry, flame tests are  used to detect the presence of certain elements, primarily metal ions, by analyzing the colour of the flame given off when heated.

above are Lithium (Li), Strontium (Sr), Sodium (Na), Copper(Cu), and Potassium (K).

NASA's MAVEN reveals Mars has metal in its atmosphere

Mars has electrically charged metal atoms (ions) high in its atmosphere, according to new results from NASA’s MAVEN spacecraft. The metal ions can reveal previously invisible activity in the mysterious electrically charged upper atmosphere (ionosphere) of Mars.

“MAVEN has made the first direct detection of the permanent presence of metal ions in the ionosphere of a planet other than Earth,” said Joseph Grebowsky of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Because metallic ions have long lifetimes and are transported far from their region of origin by neutral winds and electric fields, they can be used to infer motion in the ionosphere, similar to the way we use a lofted leaf to reveal which way the wind is blowing.” Grebowsky is lead author of a paper on this research appearing April 10 in Geophysical Research Letters.

MAVEN (Mars Atmosphere and Volatile Evolution Mission) is exploring the Martian upper atmosphere to understand how the planet lost most of its air, transforming from a world that could have supported life billions of years ago into a cold desert planet today. Understanding ionospheric activity is shedding light on how the Martian atmosphere is being lost to space, according to the team.

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Copper Crystals on a Penny 

This happens because of a displacement reaction. You have a solution supersaturated with a copper salt, and you add a metal ion that is more reactive than the copper, which steals the cation from the copper salt, leaving a bunch of disassociated copper ions in solution. If you drop the copper penny into it, it provides a nucleation site for the copper ions to deposit themselves, producing what you see in the image. (Source)

therogueofblood  asked:

'Leg so hot you fry an egg'. Explain, scientifically.

130 -155 degrees Fahrenheit (55° Celsius) is the minimum temperature required to cook an egg, the reaction occurring is actually the high protein content in the amion or clear liquid of the egg denaturing, the heat excites the molecules in the proteins till the structure of the amino acids is changed permanently and the shape and function of the protein is changed, these proteins then coagulate, turning white and becoming more viscous until firm. Be aware that at such a low temperature it can take extremely long for the egg to cook, which can lead to loss of water content and uneven cooking, so it wouldn’t taste so great.

Given that Mettaton has a jet that allows him to fly, it would be able to quickly cook an egg from a distance, but the fumes from whatever is ignited would affect the edibility of the egg.
If he were to change a few wires and ground one to the metal chassis of the leg, he could cause a short circuit, and while rapidly draining his battery and melting his electronics in his leg, he could heat up that section of the chassis and cook an egg on it, but would run out of power and destroy the leg and the connecting ports.

Given that Toriel can cook things with fire magic that does not burn people and does not actually need to use a stove, she could indeed cook an egg on her leg. It may have white fur in it.

Grillby and Fukufire may be able to cook an egg on their legs, but given the orange and green color of the flames respectively the egg may end up with metal ions and metal compounds in it, making it to toxic.

We gave a Temmie an egg, and it’s legs turned it hard boiled and dyed the shell, and now it’s somehow hatched a baby Temmie from it. We still have no clue how that happened.

Bacteria, Graphene and Nanotech Produce Usable Electricity From Wastewater

Check out the kitchen timer counting down in the gif above. There’s nothing special about it except for how it is being powered. The instrument isn’t equipped with batteries. In fact, its electricity comes from the vial behind it, where bacteria are eating organic matter in wastewater and producing electricity as a result. 

It’s the first time that researchers have produced enough electricity for practical use from what are called microbial fuel cells. Scientists in China reported their breakthrough late last week in the journal Science Advances. Their work could one day help provide the huge amounts of power needed to treat wastewater, a process that currently consumes up to 5 percent of all the electricity produced in the U.S.

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Spider Fang Study Reveals Architecture of Perfect Puncture

The picture above is a model of the mechanical load a spider’s fang must endure. Scientists in Germany and Austria have been busy studying the wandering spider’s natural syringe to better understand how similar sharp structures like stingers, claws and teeth are built.

They were interested in the fang because it must last for more than a year of the arachnid’s life and through multiple attacks on prey. While hunting, it must pierce through the tough exoskeletal cuticle of its victim to inject a potent neurotoxic venom. 

Their research looking at different structural scales to understand the fang’s mechanical properties concluded that “both the anatomical shape of the naturally evolved fang and its material-level architecture result in highly adapted effective structural stiffness and damage resilience.”

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Graphene With Nanosized Holes Could Make Dramatically Better Water Filters

by Txchnologist staff

Tiny filters measuring just one-atom thick might be the next generation of technology that efficiently separates salt and impurities from water. Researchers report that they have successfully punched subnanoscale holes in graphene, the sheets of bound carbon atoms known to be one of the strongest materials on Earth. 

They fired metal ions at the graphene to disrupt the bonds between carbon atoms, which naturally form into hexagonal rings that look like chicken wire. The graphene was then etched with a solution that dissolved the weakened bonds and formed densely packed pores.

“We bombard the graphene with gallium ions at high energy,” said Sean O’Hern, an MIT graduate student who led the research, in a university statement. “That creates defects in the graphene structure, and these defects are more chemically reactive.” 

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5 things you didn’t know about…metal organic frameworks

Credit: CSIRO

1. First developed in the 1990s, MOFs are crystalline hybrid materials created from both organic and inorganic molecules via molecular self-assembly.

2. They are formed from linkers – long chains, typically of carbon and hydrogen oxides decorated with nitrogen atoms – and positively charged metal ions, which form nodes that bind the arms of the linkers together.

3. One pea-sized gram of MOF material can host the equivalent surface area of 40 tennis courts, and because most of their bulk is empty space, MOFs are also extremely light.

4. USA, chemist Professor Omar Yaghi has pioneered research into MOFs. He authored the first published report of a MOF in 1999 and estimates that his lab alone has created in excess of 1,000 different MOF structures since.

5. One of the most promising features of MOFs is that they are applicable to carbon capture and storage (CCS). In a study by Pike Research (now part of Navigant), USA, they are expected to reach a potential market value of US$221bln by 2030.

To find out more about the history of metal organic frameworks, read our upcoming Material of the Month feature by Simon Frost in the October issue.

chemistry // michael clifford smut 

plot: michael’s failing chemistry because his attention is diverted elsewhere, so when the good girl offers to tutor him, she uses it to prove she’s not what he thinks she is
word count: 2,721
requested?: no, i just have a really cruel brain
warnings: language ish, sub michael (aaaaay lmao) 

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lisbeth-heisenberg  asked:

Hello! The other day I was wondering what is the chemical composition of fire? Does it even have one?

Good question! Flames arise from the combustion of a fuel in oxygen. The flames themselves are a mixture of reacting gases and solids produced by this reaction. The exact chemical composition will depend on what is being burned - however, they’ll often include a range of compounds containing carbon, hydrogen, and oxygen. 

The products in the flame, produced by the combustion reaction, are at such a high temperature in the flame that they exhibit incandescence. This is simply the emission of light. Different chemicals give out different coloured lights, as illustrated by the fact that different metal ions can produce different flame colours. Soot (carbon-based compounds) particles are responsible for the characteristic red/orange glow of fire.

Everything is capable of exhibiting incandescence- almost all solids will glow with a dull red colour around 525 degrees celsius. Sunlight is in fact the incandescence of the white hot surface of the sun; however, it’s worth pointing out that the sun’s energy is not produced by combustion, but by nuclear fusion in its core.

Although it’s often stated that fire is a plasma, unless it is at a very high temperature, it’s actually just incandescent gas.

References & Further Reading