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Category: chemistry – Page 190

Earth’s evolving geodynamic regime recorded by titanium isotopes

Powders of samples were weighed into precleaned Savillex beakers and dissolved with mixtures of 22 M HF and 14 M HNO3 acids in a 2:1 volume ratio. The modern OIBs and four reference materials (that is, BHVO-2, BCR-2, AGV-2 and BIR-1) were digested on a hot plate at 120 °C for four days. Note that all chondrite and Archaean ultramafic/mafic rock samples were digested in Parr bomb vessels at 220 °C for three days to ensure full dissolution of refractory phases. Dissolution of the dried samples in 5–10 ml 6 M HCl at 120 °C and evaporation was carried out several times to decompose the fluorides formed from HF digestion until clear solutions were obtained. An aliquot of each sample was taken and spiked with a prepared 47 Ti–49 Ti double spike to determine in advance the Ti concentration using an iCAP RQ inductively coupled plasma mass spectrometer at the Centre for Star and Planet Formation (StarPlan) at the University of Copenhagen. Afterwards, aliquots containing 6 µg Ti were taken and mixed with a 47 Ti–49 Ti double spike as described previously in ref. 34. The dried mixtures were dissolved with 6 M HCl at 120 °C overnight to ensure sample–spike equilibration.

Titanium was separated from matrix elements following a three-step purification protocol using AG1x8 (200–400 meshes) and DGA resins34,68, that is, first to separate Fe with 6 M HCl elution on AG1x8 columns, second to remove most of the major and trace elements through 12 M HNO3 elution and to collect Ti with Milli-Q H2O on DGA columns and third to purify Ti from the remaining matrix elements with 4 M HF cleaning on AG1x8 columns. An extra DGA pass can be carried out to remove trace amounts of Ca and Cr in the final Ti cuts. To destroy the resin particles and organics from column chemistry, the Ti cuts were treated with 14 M HNO3 at 120 °C before storage in 0.5 M HNO3 + 0.01 M HF acids.

Titanium isotopic compositions of the purified samples were measured using the ThermoFisher Scientific Neoma Multicollector ICP-MS. Sample solutions with 500–800 ppb Ti dissolved in 0.5 M HNO3 + 0.01 M HF were introduced into the multicollector inductively coupled plasma source mass spectrometer by means of an APEX HF desolvating nebulizer from Elemental Scientific and a sapphire injector was used instead of the quartz-made injector to reduce the production of silicon fluorides from the use of HF solvent. An actively cooled membrane desolvation component was attached after the APEX to suppress oxide formation and to stabilize the signals, and N2 gas at a flow rate of a few ml min−1 was added to improve the sensitivity. Such a setting typically provides an intensity of around 15 V on 48 Ti+ at an uptake rate of about 50 μl min−1 for a 600-ppb Ti solution under a medium mass-resolution mode.

New study reveals spin in quantum dots’ carrier multiplication

A new approach to developing semiconductor materials at tiny scales could help boost applications that rely on converting light to energy. A Los Alamos-led research team incorporated magnetic dopants into specially engineered colloidal quantum dots—nanoscale-size semiconductor crystals—and was able to achieve effects that may power solar cell technology, photo detectors and applications that depend on light to drive chemical reactions.

“In quantum dots comprising a lead-selenide core and a cadmium-selenide shell, manganese ions act as tiny magnets whose magnetic spins strongly interact with both the core and the shell of the quantum dot,” said Victor Klimov, leader of the Los Alamos nanotechnology team and the project’s principal investigator. “In the course of these interactions, energy can be transferred to and from the manganese ion by flipping its spin—a process commonly termed spin exchange.”

In spin-exchange multiplication, a single absorbed photon generates not one but two , also known as excitons, which occur as a result of spin-flip relaxation of an excited manganese ion.

Characterizing atomic defects in 2D materials to determine suitability as quantum emitters

The term molybdenum disulfide may sound familiar to some car drivers and mechanics. No wonder: the substance, discovered by U.S. chemist Alfred Sonntag in the 1940s, is still used today as a high-performance lubricant in engines and turbines, but also for bolts and screws.

This is due to the special chemical structure of this solid, whose individual material layers are easily displaceable relative to one another. However, molybdenum disulfide (chemically MoS2) not only lubricates well, but it is also possible to exfoliate a single atomic layer of this material or to grow it synthetically on a wafer scale.

The controlled isolation of a MoS2 monolayer was achieved only a few years ago, but is already considered a materials science breakthrough with enormous technological potential. The Empa team now wants to work with precisely this class of materials.

Machine learning enables discovery of DNA-stabilized silver nanoclusters

DNA can do more than pass genetic code from one generation to the next. For nearly 20 years, scientists have known of the molecule’s ability to stabilize nanometer-sized clusters of silver atoms. Some of these structures glow visibly in red and green, making them useful in a variety of chemical and biosensing applications.

Stacy Copp, UCI assistant professor of materials science and engineering, wanted to see if the capabilities of these tiny fluorescent markers could be stretched even further—into the near-infrared range of the electromagnetic spectrum—to give bioscience researchers the power to see through living cells and even centimeters of biological tissue, opening doors to enhanced methods of disease detection and treatment.

“There is untapped potential to extend fluorescence by DNA-stabilized silver nanoclusters into the near-infrared region,” she says. “The reason that’s so interesting is because our biological tissues and fluids are much more transparent to near-infrared light than to visible light.”

AI Unlocks Olive Oil’s Potential in Alzheimer’s Battle

This is a good use of AI. Definitely regular it but I can see it’s contributing to medical research.

Summary: Researchers have utilized artificial intelligence to uncover the promising potential of extra virgin olive oil (EVOO) in combating Alzheimer’s disease (AD).

By integrating AI, chemistry, and omics research, the study identified specific bioactive compounds in EVOO that could contribute to the treatment and prevention of AD. Ten phytochemicals within EVOO, such as quercetin, genistein, luteolin, and kaempferol, were found to exhibit potential impacts on AD protein networks.

The study adds to the growing evidence for the neuroprotective effects of a Mediterranean diet, rich in EVOO, in mitigating dementia and cognitive decline.

Potent anti-cancer therapy created using ‘click chemistry’

A potent anti-cancer therapy has been created using Nobel prize-winning “click chemistry,” where molecules click together like LEGO bricks, in a new study by UCL and Stanford University researchers.

The study, published in Nature Chemistry, opens up new possibilities for how cutting-edge cancer immunotherapies might be built in future.

The research team created an anti-cancer therapy with three components: one targeting the cancer cell, another recruiting a white blood cell called a T cell to attack the cancer cell, and a third knocking out part of the cancer cell’s defenses.