Author: Shalini Saxena

The Fukushima nuclear disaster occurred almost five years ago in March 2011. It is the largest event of its sort since Chernobyl, which occurred 25 years earlier. The accident was triggered by a tsunami and earthquake that led to a meltdown at the plant. During this event, large amounts of radioactive materials were released into the atmosphere. Since then, Fukushima Daiichi has continued to leak radioactive materials into the ground and nearby ocean.

Following the accident, concerns surfaced regarding both agricultural products from the region and the fish caught in nearby waters. In response, the Japanese government began intensively monitored γ-emitting radioisotopes to prevent highly contaminated foods from reaching the market. The two main radioisotopes released during the accident, ¹³⁴Cs and ¹³⁷Cs, exhibit half-lives of approximately 2 and 30 years, respectively. So a large amount of the radiocesium released during the accident is still around.

Recently, a team of researchers has re-examined aquatic food contamination data in order to get a better picture of food safety.

Since the tech boom began decades ago, we’ve seen a dramatic transformation of electronics. Today, some technological dreamers are talking about “smart environments” where electronics are seamlessly integrated into our environment, providing comfort and convenience.

For these dreams to be achieved, we need to get electronics—not just the chips—miniaturized to the point where sensors can be pervasive. This involves developing high-performance electrochemical storage devices to enable long-lived sensors and radio frequency identification (RFID) tags. But efficient miniaturized energy storage devices have proven to be challenging to create; it can be done, but it's hard to integrate the results with other electronics.

Supercapacitors

According to an article in Science, an international team of scientists has now reported some progress in this area—specifically with the design of micro-supercapacitors. Supercapacitors are a class of materials that can store energy through accumulation of charge at the surface of a high-surface-area carbon sheet. They typically have a good cycle life, moderate energy density (6 Wh/kg), and high power densities (> 10 kW/kg). Supercapacitors are a great replacement for batteries in applications that require high power delivery and uptake with a very long charge-discharge cycle life; micro-supercapacitors are the same kind of material but much, much smaller.

One major threat from climate change is the rising global sea level. At the coast, the rising seas will wipe out infrastructure and threaten wildlife. If ocean water moves deeper into landmasses, the salt will contaminate sources required for drinking water and agriculture.

A solid understanding of how quickly the sea level is rising, and the major contributing factors, is critical to developing practical plans to limit the problems and deal with the inevitable. Recently, a team of scientists has dived head-first into this challenge.

Effect of rising sea levels

The main factors influencing rising sea level have been well documented. First, climate change has led to increased global temperatures. As its temperature rises, the sea water expands (a process called steric expansion). In addition, ice sheets and land glaciers all over the world are shrinking through evaporation and melting. All of these factors contribute to rising ocean levels.

The chemical and thermal history of the Earth enabled the reactions required to create the building blocks of life. Our nitrogen-rich atmosphere, for example, is critical for chemical reactions that have fostered the evolution of life.

The Earth is a dynamic planet, and elements critical to the formation of life (like nitrogen and carbon) are recycled through many natural processes. One of these processes is the movement of the Earth's continents, which recycles bits of the crust and some of the chemicals it contains. Though we have been aware that the Earth’s plates have been moving for quite some time, it has been much more difficult to establish the specifics of when and how plate motion initiated.

Now, new data from some very old diamonds suggests that plate tectonics was functioning more than three billion years ago.

The natural movement of carbon through the Earth and its inhabitants is essential to life as we know it. Carbon is needed in our atmosphere for photosynthesis, it’s present in plants and our bodies, and it’s expelled back into the atmosphere by our respiration.

The world’s ocean represents a significant sink in the global carbon cycle, containing the majority of the world’s CO2 in a dissolved form. Dissolved CO2 is required for many chemical and biochemical processes critical for marine organisms. For example, the sunlit level of the ocean is filled with phytoplankton, an organism that uses sunlight and dissolved carbon dioxide to create sugars via photosynthesis.

Iron is a trace nutrient that is critical for photosynthesis. The Southern Ocean has low concentrations of dissolved iron compared to other oceans, leading to lower levels of carbon sequestration—approximately 10 percent of the global sequestration. However, scientists think that sources of iron can lead to elevated localized levels, which could dramatically increase carbon sequestration. The impact of these local changes on the overall carbon sequestration of the Southern Ocean is not well understood.

From hurricanes to heat waves, it seems that no corner of the world has been shielded from the force of extreme weather. While we tend to focus on damage to communities, agriculture has also been hit hard by these events.

The agricultural sector of developing countries accounts for almost 25 percent of all damage and losses from weather-related events. This damage can threaten everything from local food infrastructure to global food security. However, not all extreme weather events result in an agricultural disaster. These depend on several factors: the severity of the event, the susceptibility of the environmental systems, and the exposure of the human and natural systems.

Droughts and floods

Though the influence of weather-related events on agriculture has been explored, previous studies have been limited. Recently, a team of scientists have taken an empirical approach to estimate the influence of extreme weather disasters using data in three areas: cropped area, yields, and production at the global scale.

Clean water is essential, yet in certain parts of the world, it's very difficult to obtain. Unfortunately, our limited water resources are being polluted by chemicals from industrial plants, pesticides, pharmaceuticals, and more.

Adsorbant materials composed of carbon are often used to remove many of these organic pollutants. However, they act slowly, typically miss hydrophilic micropollutants, and can be difficult to reuse.

Scientists working on developing inexpensive materials that can purify water quickly have been working with an insoluble polymer called β-cyclodextrin (β-CD)—a big loop of linked sugar molecules. Recently, they've discovered a way to cross-link β-CD using aromatic groups forming a porous, cross-linked complex. The porous, cross-linked β-CD has an increased surface area that significantly speeds the removal of pollutants.

Most people think of batteries when they consider energy storage, but capacitors are an alternative in some use cases. Capacitors are used in almost all electronic devices, often to supply temporary power when batteries are being changed to prevent loss of information. In addition to everyday devices, they are also used in more obscure technologies, including certain types of weapons.

Understanding the supercapacitor

Unlike batteries, capacitors use static electricity to store energy. In their simplest form, they contain two conducting metallic plates with an insulating material (dielectric) placed in between. A typical capacitor charges instantly but usually cannot hold a great deal of charge.

Supercapacitors can at least partly overcome this shortcoming. They differ from the typical capacitor in that their "plates" provide significantly larger surface area and are much closer together. The surface area is increased by coating the metal plates with a porous substance. Instead of having a dielectric material between them, the plates of a supercapacitor are soaked in an electrolyte and separated by an extremely thin insulator.

Graphene is an exceptionally strong and conductive material composed of a single atomic layer of carbon. Its discovery sparked interest in the development of other two-dimensional (2D) materials, and, over the past decade, scientists have discovered hundreds. These materials boast abilities that could make a noticeable impact in areas such as electronics, thermal management, filtration, medicine, and more.

Now, an unusual atom—boron—has been used to produce a novel 2D material called "borophene."

Boron at the atomic level

Boron is one of the many materials that has been considered for development of 2D materials. Boron is an interesting atom to use as a building block for a number of reasons. First, it is a semi-metal, meaning it exhibits some properties of metals and some properties of nonmetals; as a 2D material, it thus has the potential to exhibit unique behavior.

None of us can avoid the effects of aging, though many of us try in various ways, through cosmetics or nutrition and wellness products. Though these things may slow or disguise the progression of age-related effects, the health-related issues of aging remain. For the most part, researchers have had little luck developing treatments to postpone, ameliorate, or prevent the accumulation of diseases throughout one’s life. People may be living longer, but it's often with a reduced quality of life due to age-related diseases.

Recently, researchers have begun to explore the basic mechanisms of aging from the cellular level to the systemic level in order to develop new strategies to prevent age-related issues and better understand them. Last week's edition of Science took a look at some of the results.

At the cellular level

Aging represents the failure to balance genetic programs for survival and reproduction once an individual has survived beyond the age of peak reproductive fitness. Though all of our cells are important, some cells are more important than others. In particular, scientists have focused their attention on understanding how aging affects a specific, critical population of our cells—stem cells. Stem cells are only a small portion of our cells, but they are able to replicate themselves indefinitely and are able to transform into specific cell types (such as a bone cell or heart cell) based on external cues.