Research reveals mechanisms of action of iron nanoparticles used in aquifer decontamination

Chlorinated hydrocarbons are among the most persistent contaminants in groundwater reserves – aquifers – worldwide. The problem is characteristic of industrialized regions, where substances were widely used, until the 1980s, as solvents, degreasers, in enamels for car painting and in dry cleaning, among other applications. Very small amounts of these pollutants are enough to make these waters unfit for human consumption, as they cause damage to the kidneys and liver, and cancer.

The usual technologies for removing this type of pollutant involve the treatment of water after it is brought to the surface. However, in addition to its high cost, this method does not fully solve the problem, as there will always be a volume of contaminant remaining on the subsurface. Because they are denser than water, chlorinated hydrocarbons sink until they reach a less permeable region, usually the bed of an aquifer. There, in the pores of the rocks, the pollutants persist for many years and are slowly carried by the waters, contaminating regions far from the source.

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Research explores wave-particle duality to accelerate light in a two-dimensional crystal using functional substrates

The understanding of light and its interaction with materials was, in the last century, an important way for scientific discoveries. A prominent example is the photoelectric effect: the emission of electrons by materials when subjected to the incidence of light at certain wavelengths. Wave theories already explained the behavior of light in many optical phenomena, but were not able to fully explain the characteristics of the photoelectric effect. The explanation for this phenomenon, as proposed by Einstein, required that the energy associated with light could only assume well-defined values, said to be discrete or quantized, that is, light should also have properties normally associated with particles.

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Research reveals new mechanisms and strategies to break plant polysaccharides and generate interesting by-products

Polysaccharides are molecules ubiquitous in nature, serving as a natural barrier for plants, energy sources for algae, and making up the cell wall of fungi. The deconstruction or modification of these polysaccharides is of great industrial interest, as in the textile and paper industry, as well as for the generation of biofuels and renewable chemical intermediates. Currently, the use of these polysaccharides in by-products of industrial interest requires the use of chemical reagents that generate environmental impacts or is carried out by industrial enzymes that are still not very efficient.

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Researchers achieve unprecedented details of the shape, composition and preservation of microfossils

For decades, scientists have been using fossils of microorganisms to better understand the origin and evolution of life on Earth, but this branch of palaeobiology has taken a great leap forward with the development of novel imaging techniques. Historically, the study of the earliest traces of life on Earth has been surrounded by a lot controversy and technical challenges. Sometimes it is even difficult to tell out if a structure is really a fossil or… just an artefact.

These challenges are related to the characteristics of these microfossils: they are only few micrometers in size (ten times less than the thickness of a human hair). Also, ancient rocks have suffered some degree of geological alteration due to the pressure and temperatures exerted by layers of rock above them. Therefore, the original components of these tiny cells have been “cooked” at temperatures of more than 100°C, substituted by minerals and pressed for hundreds of millions to billions of years, before ending up in the hand of scientists.

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Research investigates new niobium-based materials for improving electrical energy storage

The search for clean and renewable energy sources has intensified in recent years, due to the continuous increase in the concentration of greenhouse gases in the atmosphere, such as carbon dioxide. Also part of this search is the development of new systems to store and supply energy for various applications, from electric cars and buses to portable electronics. Thus, devices such as lithium batteries, flow batteries and supercapacitors are studied to meet these new demands.

Supercapacitors are a class of energy storage devices that combine the properties of batteries (high storage capacity) and capacitors (ultra-fast charging and power supply), tolerating many charge and discharge cycles. However, this type of device still has several drawbacks: the energy storage capacity is lower than that of conventional batteries; the observed voltage discharge curve can prevent the use of all stored energy; and in some cases, a high self-discharge is verified.

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Research contributes to the design of more effective antibiotics and anticancer compounds

Antibiotic resistance is a very pressing public health issue. Drug resistant bacteria are on the rise, and the number of antibiotics available to fight them are not enough. Infections by drug resistant bacteria is especially a serious problem for people with compromised immune systems, such as cancer and AIDS patients. There is also a tremendous financial burden to patients due to the need for more expensive antibiotics that often have more serious side effects. Scientists and clinicians are thus interested in finding new antibiotics, new targets, and new modes of actions to curtail emerging drug resistant bacteria.

In the cell, an enzyme called ClpP protease is responsible for removing damaged and misfolded proteins by degrading them into smaller fragments. This function is essential in maintaining protein homeostasis, whereby proteins are continually produced and removed in the act of cellular housekeeping, and this in turn sustains the life of the cell. However, this enzyme is also essential in many pathogenic bacteria because its function is linked to their ability to spread infection. Hence, the ClpP protease is one of the new and interesting targets for antibiotic drug discovery.

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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.

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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.

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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.

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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.

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