Author Archives: Charles mao

Cancer is a disease that killed 8.9 million people by 2016, and it is very hard to detect. For someone suffering cancer, they may want to detect it as early as possible so they can be treated. In the past, doctors have to take a patient’s tissue. With naked eyes, the doctor has to search for tiny cancer monsters in this tissue under a microscope, which is like searching a needle in an ocean. Even for highly-experienced doctors, this process is time-consuming and has a high chance of miss-detecting.

Cancer Deaths
(Source: Our World Data)

Now there are radioactive chemicals that can efficiently detect cancer cells. It works like this. There is a blue-colored chew-chew train in these chemicals called a positron, which collides with the red chew-chew train in your body called an electron. When they collide, they annihilate each other and make huge lightning like in a nuclear bomb. These lights are so strong that they can penetrate through your body and be captured by our detecting machine. So you might wonder, how do we know if there are cancer monsters then? Well, the cancer monsters can eat away light, so when the detecting machine receive light from areas of the patient’s body where cancer cell is present, the picture coming out would be much, much darker.

chew-chew trains colliding (source: google)

But here is another problem–––the radioactive chemicals are so dangerous that they can destroy your body, which is also why we make nuclear bombs out of them. Therefore scientists have found types of these chemicals that only explode for a few hours, on top of them is something called Germanium, it is not made in Germany, but you could memorize it that way. It’s not just normal Germanium, but a thin, thin Germanium that is a little lighter than the normal Germanium.
But the problem has not been solved. What if the Germanium jumps around your body and destroys everything? We need a claw that clamps onto this Germanium to transfer it into the patient’s body and hold it in the spot. There used to be many candidates, but they can only function at small ranges of pH outside your body. Now you must be confused; what exactly is pH? Well, think of a pool of sticky bubble gums. These gums are called H. When the pH is low, there are a lot of gums in the pool, so when the claw enters the pool, the gum will stick onto the claw, now the claw surface becomes soft, and the Germanium just slips away. Unfortunately, the human body is such a low pH pool. No claw has been able to hold the playful Germanium under every condition. Surprisingly, Dr. Ovrig just made this new big claw in his lab that would hold onto the Germanium. When they tested it in different pools, even one similar to the human body, the Germanium stayed happily inside the claw. If you are curious about the name of this claw, it’s called Ga(hox).

The researchers then brought this claw into practice. They used the claw and germanium combination on a mouse, and it easily detected cancer monsters in the heart within a short 1 minute. The monsters in the liver and bladder are also exposed after 1 hour. Now, patients no longer have to worry about the long period of cancer examination. Besides, this technique can detect even tiny amounts of cancer monsters. Therefore, even in the very early stage of cancer, the claw-germanium combo can detect cancer and allow treatment before the cancer monster goes rampart.

Reference

Wang, X.; De Guadalupe Jaraquemada-Peláez, M.; Cao, Y.; Pan, J.; Lin, K. S.; Patrick, B. O.; Orvig, C. H2hox: Dual-Channel Oxine-Derived Acyclic Chelating Ligand for 68Ga Radiopharmaceuticals. Inorg. Chem. [Online] 2019, 58, 2275-2285. (Accessed: March 23, 2020).

Responding to a need for scientific literacy in the public, researchers at the Samuel Neaman Institute examine ways to promote chemical literacy among different stakeholders.

The public increasingly encounters with real-life scientific and technological contexts, and scientific professional and chemical educators have realized the need for chemical literacy among the public to understand, and critically evaluate the scientific information they absorb. The University of British Columbia even offers a course, called CHEM 300, which teaches how to communicate scientific knowledge.

Broggan Textbook
(source: thriftbooks)

In an attempt to narrow the gap between the scientific and the non-scientific communities, researchers led by Zehavit Kohen conducted a comprehensive analysis of chemistry education methods most valued by different stakeholders.

The researchers identified four groups, K-12 students, teachers, scientists, and the educated public, from a sample population of 347. The survey divides into two sections, scientific literacy construction, and communication channel types.

According to the study, K-12 students valued cognitive and affective components twice more than scientists or educated adults. Besides, all stakeholders favored open discussions as their communication channel. Mass media dominates the scientific community besides open discussions. Whereas, students use mass media, be available to the public, and share of scientific materials indistinguishably.

Mass Media
(Source: flickr)

Investigating question posts on an ask-a-scientist-type website, the research further discovered that the public’s questions usually concern symbols over processes or systems. The type of information involved in these questions is mostly explanatory.

Data from Zehavit’s article

The results encourage students to gain chemical literacy in real-world contexts through analogies and symbols. The researchers also suggest that scientists should attempt other communication channels since interactive and affective activities on mass media are often challenging.

Reference

Zehavit, K.; Orit, H.; Yehudit J. D. How to promote chemical literacy? On-line question posing and communicating with scientists. Chem. Educ. Res. Pract., 2020, 21, 250

Double-proton emission has motivated great interests in nuclear and radiochemistry due to its extremely rare occurrence. This decay mode first appeared only as a prediction from theories on nucleon pairing; it involves the simultaneous emission of two protons in proton-very-rich nuclei, where competing single-proton emission is quantum-mechanically forbidden. Since 2002, double proton-emission was observed in experiments, but they still lacked a coherent and accurate theoretical framework.

Double-Proton Emission (made with blender/photoshop)

The group of researchers led by M. Goncalves have recently calculated the decay rate for double-proton emission, filling the missing theoretical gap. The rate of decay is fundamental to the quantification of nuclear reactions; theoretical decay rates from this research will provide the basis for future double-proton reaction designs.

Nucleons are massive and inert to physical conditions, thus nuclear reactions are only quantified statistically using special relativity and quantum mechanics. To tackle this, the researchers used the effective liquid drop model, widely used in alpha decay and cold fission calculations. This model assumes that nucleons interact with each other like particles in a droplet of water.

Liquid Drop Model
(Source:People’s University, Bhopal)

From known values of mass excess, coulomb’s barrier, and dimensional parameters, the researchers calculated the double-proton emission half-life for nuclides mass below 70u. The log of half-life is then plotted against parameter q, derived from the decay energy of each nuclide.

The available experimental double-proton emission half-lives for 16Ne, 19Mg, 45Fe, 48Ni, 54Zn and 67Kr are then plotted on the graph. The experimental values matched closely with the theoretical calculations, except 16Ne; a possible explanation for the deviation may be its mass number away from nuclear magic numbers.

When not using a log variable, the differences between experimental and

theoretical values seem significant. Nevertheless, in the field of nuclear science, this scale of difference is already near-perfection; even the best models such as SEME shows a deviation above 4-times for nuclear binding energy calculations.

A study led by the University of British Columbia reveals the potential of applying short-lived radioactive species in ordinary chemical reactions.

Stable isotopes–––atoms of lifetime longer than the age of the universe (t1/2> ~10^20 years)–––predominate the every-day chemistry labs. Introducing radioactive isotopes in chemical reactions can greatly improve the diversity of available reaction mechanisms. But most of these isotopes have an extremely short lifetime, decaying into the void before any reaction will occur. 

An Imaginary Muon Source: Scorge (Deviantart)

The team led by Fleming and Macfarlane successfully introduced a highly unstable hydrogen isotope, muonium, in reactions with gold nanoparticles (AuNPs) and benzene molecules. Theoretical calculations on relevant reaction rates and quantum mechanical variables are now realized in real-life experiments.

In this study, short-lived muonium nuclides were produced from a particle accelerator at TRIUMF. It had a mean lifetime of only 2.2 microseconds, and possess only one-tenth the mass of stable hydrogen. 

TRIUMF particle accelerator at the University of British Columbia

The first reaction took place inside a cell that contained porous silica-coated AuNPs. Here, Bz vapor of known pressure monitors the study of reaction rate. Interestingly, upon introducing the Bz vapor into the reaction cell, the pressure decreased dramatically to near-zero, and its constant changes were good indications of changes in the reaction rate.

The muonium is then reacted with benzene, creating a muonated benzene radical. Radicals are highly reactive species with one unpaired electron, and they are synthesized in organic labs in limited ways. The radioisotope may build onto current techniques in creating a radical.

The researchers also analyzed the catalyzing effect of AuNPs on the muonium benzene reaction. The results show considerable weaker binding energy of benzene on AuNPs than on bulk gold metal surfaces, which indicates that the presence of AuNPs increased the reaction rate.

Gold nanoparticle
Source: Equinox Graphics (Flickr)

In Chemistry, AuNPs are great heterogeneous catalysts––––reaction accelerators that differ in phase from the reactants. These solid catalysts all together account for 90% of the catalysts used worldwide. The successful catalysis in muonium reactivity demonstrates the possible use of heterogeneous catalysts in radioisotopic reactions that await to be explored.

Besides, the reaction of AuNPs with radioisotopes would inspire more detailed studies into their biomedical benefits as cancer detectors and drug deliverers.

Unique optical properties of various sized gold. Source: Sigma-Aldrich

This avant-garde reaction will inspire the development of chemical reactions into the unstable nuclides, where new reaction pathways lie.