# Science

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With open facilities, the Brazilian Synchrotron Light Laboratory (LNLS) annually welcomes about 1200 Brazilian and foreign researchers, committed to more than 400 studies that result in approximately 200 articles published in scientific journals. Check out below some of the many investigations that have benefited from LNLS facilities.

# Nanotechnology against bacterial resistance

Research investigates the use of nanoparticles to accurately deliver drugs to pathogens

Antibiotic resistant bacteria are one of the most alarming public health problems, causing approximately 700,000 fatalities each year. The emergence of new resistant bacteria and the lack of effective drugs are some of the challenges in this complex medical landscape. If nothing is done, this number is estimated to rise to around 10 million deaths by 2050.

The administration of multiple cycles of antibiotics stimulates the emergence of resistant bacteria, and multidrug-resistant pathogens force patients into prolonged hospital stays, also increasing the costs associated with treatment.

# Towards more efficient photovoltaic cells

Research presents nanoscale chemical composition mapping of materials for solar energy production

The search for clean and renewable energy sources has intensified in recent years, including, for example, the conversion of sunlight into electricity through photovoltaic cells. Simply put, sunlight incident on these devices is absorbed by electrons in the material. They are expelled from the atoms or molecules to which they were associated, forming the electric current that will be used to charge a battery or to operate other electric devices.

Silicon ($\rm Si$), an abundant material on Earth's crust, is the basis of most solar panels installed today. However, despite the continuous reduction of production costs, silicon is not very efficient for the conversion of solar energy. This efficiency depends on intrinsic properties of the materials used to make photovoltaic cells and increases year by year with the discovery of new and better materials.

# Galactic Factories of Organic Compounds

Research investigates the fragmentation of complex molecules around active galaxy nuclei

A galaxy is a gravitationally bound system made up of stars, gases – mainly hydrogen and helium – and, to a lesser extent, other heavier chemical elements. The visible universe is estimated to house trillions of galaxies and each galaxy is estimated to contain from a few hundred million ($\rm 10^8$) to one hundred trillion ($\rm 10^{14}$) stars. The galaxy where we are located is called the Milky Way and our Sun orbits the galactic center at a distance of 27,000 light-years (one light-year is the distance light travels in a year, approximately 10 trillion kilometers).

Observational evidence suggests that the center of almost all large galaxies, including the Milky Way, is made up of a supermassive black hole, millions or even billions of times more massive than our Sun. A portion of these galaxies have luminosity in some ranges of the electromagnetic spectrum – from radio waves to gamma rays - incompatible with what would be produced by their stars only. They have what is called an active galactic nucleus (AGN) and are among the greatest energy sources in the universe.

# In search of the safe use of nanomaterials

Researchers report unprecedented toxicological analysis of multifunctional nanoparticles

Nanoparticles, clusters of atoms typically between 1 and 100 nanometers in size, have been investigated across a wide range of fields of knowledge. The properties of these tiny particles can be controlled by their composition, size and shape. This way, they are adaptable to virtually every kind of application. For example, multipurpose nanomaterials, combining properties such as optical and magnetic properties, are promising in a variety of biotechnological applications such as cancer treatment, diagnosis, screening, among others.

# Steel production by 3-D printing

Research investigates effect of additive manufacturing on aerospace materials

Aerospace vehicles - airplanes, helicopters, rockets, spacecraft, satellites and others - are subject to extreme conditions of temperature, pressure and mechanical load during their operation. Thus, materials and manufacturing methods used in the aerospace industry are constantly evolving, always seeking increased reliability and weight reduction without sacrificing mechanical performance.

An important class of materials for the aerospace industry is the Maraging steel. They feature high mechanical strength and are used in components such as landing gear for airplanes or helicopters and even rocket fairing, which are subjected to high mechanical loads and fatigue cycles.

Additive manufacturing – popularly known as 3-D printing – has revitalized the manufacture of components with shapes previously considered challenging, or even impossible, and increased the potential for use of different engineering materials. However, although the structure and chemical composition of a given material is known, the product obtained in the additive manufacturing process is fundamentally different from what is obtained by conventional manufacturing processes such as casting or welding.

# Research investigates the “concrete cancer”

Results may contribute to a better understanding of the chemical reaction that causes the degradation of concrete structures

Concrete is the most used material in construction and, consequently, one of the most consumed materials by humankind. It can be part of virtually every type of construction, from homes to large infrastructures such as bridges and dams. The strength and durability of concrete depend on the proportion of its constituents: Portland cement, sand, gravel and water.

Cement is a fine powder produced from limestone and clay that, with addition of water, becomes a binder paste that hardens through a series of complex chemical reactions. After hardening, the concrete retains its structure even if it comes back in contact with water. Over time, however, concrete can be degraded by many physical and chemical factors.

The alkali-silica reaction (ASR), also known as “concrete cancer”, is a chemical reaction between silica present in aggregates and alkaline hydroxides formed from cement constituents. The product of this reaction is a hygroscopic gel that expands in the presence of water, generating mechanical stress and widespread cracking.

# Monitoring food safety of marine fishes

Research investigates the concentration of chemical elements in commercial species

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 accumulation of chemical elements in organisms depends on several factors, such as the type of element, the form of assimilation, the species and the metabolism in different tissues. For example, tissues with high metabolic rates, such as liver and kidney, may have a high concentration of metals, especially those with potential toxic effects.

Research investigates the addition of niobium to catalysts to improve alternative fuels

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.

# Enhancing solar energy production

Research investigates ways to convert titanium dioxide into a new photoactive material in the visible light range

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).

# Analyzing the structural disorder of nanocrystals

Research applies unprecedented technique in Brazil for the investigation of crystalline nanoparticles

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.

The possibility of regulating the optical and electrical properties of nanoparticles by controlling their composition, shapes and sizes opens the door to an immense variety of applications. In this context, nanocrystals - nanometric particles that have a crystalline structure - have attracted great interest.