Author: chemistadmin

Nitrogen oxides (NO_x) are a group of gases formed by nitric oxide and nitrogen dioxide. They are produced, above all, by the burning of fossil fuels. Due to their harmful effects on human health and the environment, in recent years they have been in the scientific community’s crosshairs.

A research team at the Chemical Institute for Energy and the Environment (IQUEMA), attached to the University of Cordoba, has developed a photocatalytic material capable of effectively reducing these gases, achieving results similar to others developed to date, but through a more economical and sustainable process. The findings are published in the journal Advanced Sustainable Systems.

There are chemical reactions that can be favored or accelerated in the presence of light. In the case of nitrogen oxides, light energy, in the presence of a material that functions as a catalyst, makes it possible to oxidize the nitrogen oxides in the atmosphere and convert them into nitrates and nitrites.

The first author of this research paper, Laura Marín, explained that, unlike other photocatalytic reactions, which only operate under ultraviolet light, this new material boasts the advantage of working effectively with visible light, which is much more abundant and makes up most of the solar spectrum, allowing greater use to be made of the sun’s energy.

To do this, the research team has synthesized a new compound by combining two different types of materials: carbon nitride (which allows the reaction to be activated in the presence of visible light) and lamellar double hydroxides, which have the capacity to catalyze the reaction, in addition to featuring economical and easily scalable production.

Professor Ivana Pavlovic, one of the researchers who participated in the study, explained that the new process is capable of converting 65% of nitrogen oxides under visible light irradiation, a percentage very similar to that achieved by other photocatalysts, but with the advantage that this new system uses minerals such as magnesium and aluminum, which are “cheaper, abundant in nature, and benign, compared to other photocatalysts used to date, which contain cadmium, lead or graphene,” the researcher pointed out.

Professor of Inorganic Chemistry and IQUEMA Director Luis Sánchez explained that, in this way, the work represents an important step towards the large-scale development of a system that makes it possible to decontaminate the air under real-world conditions, thus reducing one of the most common pollutant gases in cities, and one whose long-term effects can cause serious health problems.

Currently, most vitamins are produced in factories, either synthetically or with the help of microorganisms that are not approved for food use. These production methods require extensive and often complex purification processes (to separate the vitamin from non-food-approved materials), which are costly and energy-intensive.

Now, a team of researchers from the Technical University of Denmark (DTU) has successfully produced vitamin B2, also known as riboflavin, in significant quantities using a novel, cost-effective, and climate-friendly method.

The researchers employed a food-approved lactic acid bacterium, demonstrating that it can produce vitamin B2 when subjected to heat. The study is published in the Journal of Agricultural and Food Chemistry.

“I think it’s beautiful that something as simple as gentle heating and lactic acid bacteria can be used to produce vitamin B2. The method allows for food to be fortified with vitamin B2 in an easy way, for example, during the production of yogurt or sourdough,” says Associate Professor Christian Solem from DTU National Food Institute, who led the research.

Vitamin B2 is essential for energy production and for maintaining a normal immune function. It also plays an important role in iron absorption, and deficiency has wide-ranging effects.

Fortification with B2 as part of food preparation

This innovative method integrates vitamin production into the food fermentation process. Vitamins can thus be produced and added locally. By using riboflavin-producing bacteria in food production, manufacturers can improve the nutritional value of traditional foods economically, enhancing public health while reducing environmental impact.

The method differs from existing technologies by being natural—without genetic modification—and consuming less energy and fewer chemicals compared to traditional synthetic vitamin production. Fortification only requires basic fermentation tools, which are already common in many households.

How the researchers stressed the bacteria

The team subjected lactic acid bacteria to “oxidative stress,” a natural pressure that compels bacteria to produce more riboflavin to protect themselves.

“We used the microorganism Lactococcus lactis, commonly known from cheese and cultured milk, to produce vitamin B2. Lactococcus thrives best at around 30°C, but we heated the bacteria to 38–39°C, which they didn’t like. Bacteria adapt to new conditions, and to defend themselves against the oxidative stress caused by the heat, they started producing vitamin B2,” explains Solem.

The researchers optimized the vitamin production process by adding various nutrients, achieving a production of 65 milligrams of vitamin B2 per liter of fermented substrate—nearly 60 times the daily human requirement for the vitamin.

Cultural compatibility and future potential

“It would be ideal to package these B2-producing lactic acid bacteria as a starter culture that can be added to foods like milk, maize, or cassava for fermentation. When these foods are fermented using the starter culture, which includes specially selected lactic acid bacteria along with traditional ones, they automatically produce riboflavin while maintaining the traditional flavor and texture of the food,” says Christian Solem.

Many developing countries already have strong traditions of fermenting foods, which extends shelf life and reduces waste.

The method could potentially be expanded to produce other essential vitamins and nutrients, such as folic acid (B9) and vitamin B12, which are often lacking in plant-based diets. It could also be applied to various food types, including sauerkraut.

DNA stores the instructions for life and, along with enzymes and other molecules, computes everything from hair color to risk of developing diseases. Harnessing that prowess and immense storage capacity could lead to DNA-based computers that are faster and smaller than today’s silicon-based versions.

As a step toward that goal, researchers report in ACS Central Science a fast, sequential DNA computing method that is also rewritable—just like current computers.

“DNA computing as a liquid computing paradigm has unique application scenarios and offers the potential for massive data storage and processing of digital files stored in DNA,” says Fei Wang, a co-author of the study.

In living organisms, DNA expression occurs sequentially: Genes are transcribed into RNA, which is translated into proteins. This process happens to many genes simultaneously and repeatedly. If researchers can duplicate this complex, elegant dance in DNA-based computers, these devices could be more powerful than current silicon-based machines.

Researchers have demonstrated sequential DNA computing for very focused, specialized tasks. But until recently, not much progress had been made in developing more general and programmable DNA devices that could be used and reused for various applications.

In previous research, Chunhai Fan, Wang and colleagues developed a programmable DNA integrated circuit with many logic gates that act as instructions for the circuit’s operations. Here’s how it worked:

• Data, 0 or 1, was represented by a short piece of single-stranded DNA, called an oligonucleotide, that contained a series of bases: adenine, thymine, guanine and cytosine. (In nature, the sequence of bases codes for a gene.)
• For example, two inputs of 1 (DNA strands 1 and 2) would interact with an OR logic gate DNA molecule.
• Then in a fluid-filled tube, the input oligonucleotide interacted with a logic gate DNA molecule and generated an output oligonucleotide.
• The output oligonucleotide bound to a different single-stranded DNA that was folded into an origami-like structure, called a register in computer lingo.
• The oligonucleotide was “read” by reviewing its base sequence, released and used in a vial containing the next gate, and so on.

This process took hours, and someone had to manually transfer the oligonucleotide from one gate to another vial for the next computing operation. So the team, along with Hui Lv and Sisi Jia, wanted to speed things up.

To make the reaction processes more efficient and compact, the team first placed the DNA origami register onto a solid glass 2D surface. The output oligonucleotide floating in liquid from a specific logic gate then attached to the glass-mounted register.

After the output oligonucleotide was read and the logic gate instructions determined, it detached, which reset the register so it could be rewritten, thereby avoiding the need to move or replace registers.

The researchers also designed an amplifier that boosted the output signal so all the pieces—the gates, oligonucleotides and registers—could find one another more easily. In a proof-of-concept experiment, all the DNA computing reactions took place in a single tube within 90 minutes.

“This research paves the way for developing large-scale DNA computing circuits with high speed and lays the foundation for visual debugging and automated execution of DNA molecular algorithms,” says Wang.

Street art takes many forms, and the vibrant murals on the Berlin Wall both before and after its fall are expressions of people’s opinions. But there was often secrecy around the processes for creating the paintings, which makes them hard to preserve. Now, researchers reporting in the Journal of the American Chemical Society have uncovered information about this historic site from paint chips by combining a handheld detector and artificial intelligence (AI) data analysis.

“The research highlights the powerful impact of the synergy between chemistry and deep learning in quantifying matter, exemplified in this case by pigments that make street art so captivating,” says Francesco Armetta, a co-author of the study.

To restore or conserve art, it’s important to collect information on the materials and application techniques. But the painters of the Berlin Wall didn’t document this. In previous studies of other historic artifacts, scientists brought fragments or even whole objects into the lab and, without destroying the samples, identified pigments on them using a technique known as Raman spectroscopy. Although handheld Raman devices are available for on-site investigations, they lack the precision of full-sized laboratory equipment.

So, Armetta, Rosina Celeste Ponterio and colleagues wanted to develop an AI algorithm that could analyze the output of portable Raman devices to more accurately identify pigments and dyes. In an initial test of the new approach, they analyzed 15 paint chips from the Berlin Wall.

The researchers first magnified the chips and observed that they all had two or three layers of paint with visible brush strokes. The third layer in contact with the masonry appeared white, which they suggest is from a base coat used to prepare the wall for painting.

Next, the researchers used a handheld Raman spectrometer to analyze the chips and compared them to spectra collected from a commercial pigment spectra library. They identified the primary pigments in the samples as: azopigments (yellow- and red-colored chips), phthalocyanins (blue and green chips), lead chromate (green chips) and titanium white (white chips). These results were confirmed with other non-destructive techniques, including X-ray fluorescence and optical fiber reflectance spectroscopy.

Then, the researchers mixed pigments from a commercial acrylic paint brand (used in Germany since the 1800s) with different ratios of titanium white, trying to match colors and the range of tints typical for painters. A knowledge of these ratios could help art conservators prepare the right materials for restoration, say the researchers.

Using the mixtures’ handheld Raman spectral data, they trained a machine learning algorithm to determine the percentage of pigment. The approach indicated that the Berlin Wall paint chips contained titanium white and up to 75% of pigment, depending on the piece analyzed and according with the color tone. The researchers say these results indicate that their AI model could provide high-quality information for art conservation, forensics and materials science in settings where it’s hard to bring lab equipment to a site.