Tag Archives: sugar

Spheres Trick, Trap and Terminate Water Contaminant

Rice University scientists have developed something akin to the Venus’ flytrap of particles for water remediationMicron-sized spheres created in the lab of Rice environmental engineer Pedro Alvarez are built to catch and destroy bisphenol A (BPA), a synthetic chemical used to make plasticsBPA is commonly used to coat the insides of food cans, bottle tops and water supply lines, and was once a component of baby bottles. While BPA that seeps into food and drink is considered safe in low doses, prolonged exposure is suspected of affecting the health of children and contributing to high blood pressure. The good news is that reactive oxygen species (ROS) – in this case, hydroxyl radicals – are bad news for BPA. Inexpensive titanium dioxide releases ROS when triggered by ultraviolet light. But because oxidating molecules fade quickly, BPA has to be close enough to attack. That’s where the trap comes in.

Close up, the spheres reveal themselves as flower-like collections of titanium dioxide petals. The supple petals provide plenty of surface area for the Rice researchers to anchor cyclodextrin molecules. Cyclodextrin is a benign sugar-based molecule often used in food and drugs. It has a two-faced structure, with a hydrophobic (water-avoiding) cavity and a hydrophilic (water-attracting) outer surface. BPA is also hydrophobic and naturally attracted to the cavity. Once trapped, ROS produced by the spheres degrades BPA into harmless chemicals.

In the lab, the researchers determined that 200 milligrams of the spheres per liter of contaminated water degraded 90 percent of BPA in an hour, a process that would take more than twice as long with unenhanced titanium dioxide. The work fits into technologies developed by the Rice-based and National Science Foundation-supported Center for Nanotechnology-Enabled Water Treatment because the spheres self-assemble from titanium dioxide nanosheets.

Petals” of a titanium dioxide sphere enhanced with cyclodextrin as seen under a scanning electron microscope. When triggered by ultraviolet light, the spheres created at Rice University are effective at removing bisphenol A contaminants from water.

Most of the processes reported in the literature involve nanoparticles,” said Rice graduate student and lead author Danning Zhang. “The size of the particles is less than 100 nanometers. Because of their very small size, they’re very difficult to recover from suspension in water.

The research is detailed in the American Chemical Society journal Environmental Science & Technology.

Source: http://news.rice.edu/

Nanoparticles Destroy Dental Plaque, Prevent Tooth Decay

Combine a diet high in sugar with poor oral hygiene habits and dental cavities, or caries, will likely result. The sugar triggers the formation of an acidic biofilm, known as plaque, on the teeth, eroding the surface. Early childhood caries is a severe form of tooth decay that affects one in every four children in the United States and hundreds of millions more globally. It’s a particularly severe problem in underprivileged populations.

Treatment with a nanoparticle and hydrogen peroxide (right panel) left little in the way of bacteria (in blue) or the sticky biofilm matrix (in red), making the combination a potent force against dental plaque

In a study published in Nature Communications, researchers led by Hyun (Michel) Koo of the University of Pennsylvania School of Dental Medicine in collaboration with David Cormode of Penn’s Perelman School of Medicine and School of Engineering and Applied Science used FDA-approved nanoparticles to effectively disrupt biofilms and prevent tooth decay in both an experimental human-plaque-like biofilm and in an animal model that mimics early-childhood caries. The nanoparticles break apart dental plaque through a unique pH-activated antibiofilm mechanism.

It displays an intriguing enzyme-like property whereby the catalytic activity is dramatically enhanced at acidic pH but is ‘switched off’ at neutral pH conditions,” says Koo, professor in Penn Dental Medicine’s Department of Orthodontics. “The nanoparticles act as a peroxidase, activating hydrogen peroxide, a commonly used antiseptic, to generate free radicals that potently dismantle and kill biofilms in pathological acidic conditions but not at physiological pH, thus providing a targeted effect.”

Because the caries-causing plaque is highly acidic, the new therapy is able to precisely target areas of the teeth harboring pathogenic biofilms without harming the surrounding oral tissues or microbiota. The particular iron-containing nanoparticle used in the experiments, ferumoxytol, is already FDA-approved to treat iron-deficiency, a promising indication that a topical application of the same nanoparticle, used at several-hundred-fold lower concentration, would also be safe for human use.

Source: https://penntoday.upenn.edu/

Electric Car Made Of Flax And Sugar

Noah is an electric city car with two comfortable seats and a spacious trunk, a top speed of 110 kilometers per hour and a range of 240 kilometers. The expected consumption in urban traffic is approximately equal to 300 kilometers to 1 liter of petrol. This is partly due to the low weight. Without batteries Noah weighs 360 kg, which is less than half that of comparable production cars. The car only needs 60 kilos of batteries, whereas regular electric cars need several hundreds kilos. The low total weight of 420 kg enables particularly good road holding. The prototype will soon be certified for use on public roads.

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TU/ecomotive is a student team of TU Eindhoven (Netherlands) that devises and builds a new sustainable car every year. The aim of this year was to show that it is possible to make a car that has a low environmental impact over its entire life cycle, without being Spartan.

A special aspect of Noah is the use of a bioplastic which can be made from sugar. The chassis and the interior are made of particularly strong sandwich panels, made of this bioplastic and flax fiber. The body is made of flax mats that are injected with a bio-based resin. These biological and particularly light materials require up to six times less energy to produce than the usual lightweight car materials such as aluminum or carbon. Still, the students claim that they have the necessary strength, and it is also possible to create a crumple-zone-like structure. Flax is a widely used intermediate crop that is essential to soil enrichment, so its cultivation does not compete with food production.

During the summer months, the team is visiting European car manufacturers, suppliers and universities, among others. The students have no plans to bring the car to market. “It’s about awareness,” says team member Cas Verstappen, a student of Automotive Technology at TU/e. “We want to show that a circular economy is already possible in complex products such as cars.” He does not expect similar cars to come onto the market immediately, but he sees the use of bioplastic panels in the structural parts and the interior as a real option. Not only because of their durability, but also because they are strong and light.

Source: https://www.tue.nl/