Marine fish are considered a source of high-quality protein and are rich in essential amino acids, fats, vitamins and many essential chemical elements such as calcium, iron and selenium. However, the presence of potentially toxic inorganic elements can cause everything from neurological and endocrine problems to increased cancer incidence. Metals such as mercury, lead and cadmium are toxic even when consumed at low concentrations, and their adverse effects are magnified by accumulating in animal tissues. On the other hand, even elements like zinc and chromium, which play important roles in metabolism, can cause toxic effects if consumed in excess.

The increasing concentration of greenhouse gases in the atmosphere, caused by human activity, is considered the main cause for the increase in the average temperature of the planet. As a result, the search for renewable alternatives to fossil fuels has intensified, such as the transformation of biomass from agriculture into renewable fuels. For example, pyrolysis oil, also known as bio-oil, is obtained by heating dry biomass to high temperatures, in the absence of oxygen, with subsequent cooling. Bio-oil is a complex mixture of organic compounds that can be used in place of petroleum to produce fuels and other chemicals.

The search for clean and renewable energy sources has intensified in recent years due to the increase in atmospheric concentration of greenhouse gases and the consequent increase in the average temperature of the planet. One such alternative source is the conversion of sunlight into electricity through photovoltaic panels. The efficiency in this conversion depends on the intrinsic properties of the materials used in the manufacturing of the panels, and it increases year by year with the discovery of new and better materials. As such, solar energy is expected to become one of the main sources of electric energy by the middle of this century, according to the International Energy Agency (IEA).

The development of faster and more efficient electronic devices, better catalysts for the chemical industry, alternative energy sources, and so many other technologies depends increasingly on the in-depth understanding of the behavior of materials at the nanometer scale. The properties of particles on this scale may be completely different from the properties of the same material in its macroscopic version. In addition, nanoparticles of different sizes and shapes can have completely different characteristics, even though they are formed by the same material.

Photonics is the science that investigates phenomena related to light, such as its generation, transmission and detection. Its applications can be found in a wide range of technologies that directly impact our daily life: lasers used in surgery, fiber optics for data transmission, and screens of high definition TVs and smartphones. These advances are only possible by the in-depth knowledge of the interaction of light with supercompact electronic components.

Complete combustion of both fossil and biofuels generates carbon dioxide ($\rm CO_2$) and water as final products. However, incomplete combustion of these substances can occur in automobile engines, generating important pollutants such as carbon monoxide ($\rm CO$), hydrocarbons, and nitrogen oxides (such as $\rm NO$ and $ \rm NO_2$).

Sugarcane is cultivated in several countries around the world, mainly to produce sugar and alcohol obtained from the juice extracted during the milling process. The remaining fresh bagasse is a material rich in cellulose and lignin, but also in water. Even with the extreme efficiency of the operations in the sugarcane industry, after all the juice extraction stages in the mill, the fresh bagasse is still composed of almost 50% of water.

Plant cells are encased in a structure called the cell wall, composed mainly of cellulose and lignin. Among other functions, this wall gives structural stability to the cells and controls the entry of water, minerals and other substances. When they die, the cells leave behind their cell wall, forming different structures that support the plant giving rigidity to the stems and that facilitate the transport of substances from the roots to the leaves and vice versa. One such structure is the xylem: a continuous network of conduits about 100 micrometers in diameter that carries the water absorbed by the roots to the leaves.

The Human Immunodeficiency Virus type-1 (HIV-1) currently infects 37 million people worldwide, with an additional 2 million new infections each year. Following infection, the virus has a long period of latency, during which it multiplies without causing symptoms. HIV attacks the cells of the immune system, especially the cells called CD4+ T-lymphocytes, which are responsible for triggering the body's response chain against infections. Thus, by suppressing the action of the immune system, the virus destroys the body's ability to defend itself against other diseases, leading to the so-called Acquired Immunodeficiency Syndrome, or AIDS.

Catalysts are materials that promote and accelerate chemical reactions without being consumed during the process. For example, catalysts are used, for example, to reduce the emission of toxic gases, such as the carbon monoxide ($\rm CO$) produced by car engines. The catalytic converters present in the exhaust of vehicles allows the $\rm CO$ oxidation reaction to occur, that is, in the presence of a catalyst, $\rm CO$ reacts with the oxygen gas ($\rm O_2$) leading to the formation of carbon dioxide ($\rm CO_2$).