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Archive for the ‘chemistry’ category: Page 245

Mar 26, 2021

Three-dimensional, multifunctional neural interfaces for cortical spheroids and engineered assembloids

Posted by in categories: biotech/medical, chemistry, evolution, neuroscience

Three-dimensional (3D), submillimeter-scale constructs of neural cells, known as cortical spheroids, are of rapidly growing importance in biological research because these systems reproduce complex features of the brain in vitro. Despite their great potential for studies of neurodevelopment and neurological disease modeling, 3D living objects cannot be studied easily using conventional approaches to neuromodulation, sensing, and manipulation. Here, we introduce classes of microfabricated 3D frameworks as compliant, multifunctional neural interfaces to spheroids and to assembloids. Electrical, optical, chemical, and thermal interfaces to cortical spheroids demonstrate some of the capabilities. Complex architectures and high-resolution features highlight the design versatility. Detailed studies of the spreading of coordinated bursting events across the surface of an isolated cortical spheroid and of the cascade of processes associated with formation and regrowth of bridging tissues across a pair of such spheroids represent two of the many opportunities in basic neuroscience research enabled by these platforms.

Progress in elucidating the development of the human brain increasingly relies on the use of biosystems produced by three-dimensional (3D) neural cultures, in the form of cortical spheroids, organoids, and assembloids (1–3). Precisely monitoring the physiological properties of these and other types of 3D biosystems, especially their electrophysiological behaviors, promises to enhance our understanding of the interactions associated with development of the nervous system, as well as the evolution and origins of aberrant behaviors and disease states (4–8). Conventional multielectrode array (MEA) technologies exist only in rigid, planar, and 2D formats, thereby limiting their functional interfaces to small areas of 3D cultures, typically confined to regions near the bottom contacting surfaces.

Mar 24, 2021

Complex Carbon-Based Molecules Found in Space – “A Major Leap Forward in Astrochemistry”

Posted by in categories: chemistry, space

Discovery may offer clues to carbon’s role in planet and star formation. Much of the carbon in space is believed to exist in the form of large molecules called polycyclic aromatic hydrocarbons (PAHs). Since the 1980s, circumstantial evidence has indicated that these molecules are abundant in space.

Mar 23, 2021

Humans Contain 42 Mystery Chemicals, Which Is Slightly Concerning

Posted by in category: chemistry

We’re not really sure where they came from.


Just as you contain multitudes, your body contains multiple chemicals—a total of 109, in fact, including 55 that have never been reported in humans before, and 42 “mystery chemicals” that come from unknown environmental sources, according to a new study from UC San Francisco.

In the study, which appears in Environmental Science and Technology, scientists revealed the chemicals found in pregnant women’s bodies. They say the chemicals have likely been in there for a while, but high-resolution spectrometry has only just begun to reveal them in detail. To test chemicals, researchers also rely on pure “standard” samples made by manufacturers, which they can’t always get ahold of.

Mar 22, 2021

Plasmonic nanoreactors regulate selective oxidation via energetic electrons and nanoconfined thermal fields

Posted by in categories: chemistry, energy, engineering, nanotechnology

When optimizing catalysis in the lab, product selectivity and conversion efficiency are primary goals for materials scientists. Efficiency and selectivity are often mutually antagonistic, where high selectivity is accompanied by low efficiency and vice versa. Increasing the temperature can also change the reaction pathway. In a new report, Chao Zhan and a team of scientists in chemistry and chemical engineering at the Xiamen University in China and the University of California, Santa Barbara, U.S., constructed hierarchical plasmonic nanoreactors to show nonconfined thermal fields and electrons. The combined attributes uniquely coexisted in plasmonic nanostructures. The team regulated parallel reaction pathways for propylene partial oxidation and selectively produced acrolein during the experiments to form products that are different from thermal catalysis. The work described a strategy to optimize chemical processes and achieve high yields with high selectivity at lower temperature under visible light illumination. The work is now published on Science Advances.

Catalysts

Ideal catalytic processes can produce desired target products without undesirable side effects under cost-effective conditions, although such conditions are rarely achieved in practice. For instance, high efficiency and high selectivity are antagonistic goals, where a relatively high temperature is often necessary to overcome the large barrier of oxygen activation to achieve high reactant conversion. Increasing the functional temperature can also lead to overoxidized and therefore additional byproducts. As a result, researchers must compromise between selectivity and efficiency. For instance, a given molecule typically requires diverse catalysts to generate different products, where each catalyst has different efficiency and selectivity. To circumvent any limitations, they can use surface plasmons (SPs) to redistribute photons, electrons and heat energy in space and time.

Mar 22, 2021

Action potentials induce biomagnetic fields in carnivorous Venus flytrap plants

Posted by in categories: biotech/medical, chemistry, neuroscience, quantum physics

“Previously reported detection of plant biomagnetism, which established the existence of measurable magnetic activity in the plant kingdom, was carried out using superconducting-quantum-interference-device (SQUID) magnetometers1, 5, 16. Atomic magnetometers are arguably more attractive for biological applications, since, unlike SQUIDs34, 35, they are non-cryogenic and can be miniaturized to optimize spatial resolution of measured biological features14, 15, 36. In the future, the SNR of magnetic measurements in plants will benefit from optimizing the low-frequency stability and sensitivity of atomic magnetometers. Just as noninvasive magnetic techniques have become essential tools for medical diagnostics of the human brain and body, this noninvasive technique could also be useful in the future for crop-plant diagnostics—by measuring the electromagnetic response of plants facing such challenges as sudden temperature change, herbivore attack, and chemical exposure.”


Upon stimulation, plants elicit electrical signals that can travel within a cellular network analogous to the animal nervous system. It is well-known that in the human brain, voltage changes in certain regions result from concerted electrical activity which, in the form of action potentials (APs), travels within nerve-cell arrays. Electro-and magnetophysiological techniques like electroencephalography, magnetoencephalography, and magnetic resonance imaging are used to record this activity and to diagnose disorders. Here we demonstrate that APs in a multicellular plant system produce measurable magnetic fields. Using atomic optically pumped magnetometers, biomagnetism associated with electrical activity in the carnivorous Venus flytrap, Dionaea muscipula, was recorded. Action potentials were induced by heat stimulation and detected both electrically and magnetically.

Mar 19, 2021

Chemical cocktail creates new avenues for generating muscle stem cells

Posted by in categories: biotech/medical, chemistry

A UCLA-led research team has identified a chemical cocktail that enables the production of large numbers of muscle stem cells, which can self-renew and give rise to all types of skeletal muscle cells.

Mar 16, 2021

Discovery identifies non-DNA mechanism involved in transmitting paternal experience to offspring

Posted by in categories: biotech/medical, chemistry, health

It has long been understood that a parent’s DNA is the principal determinant of health and disease in offspring. Yet inheritance via DNA is only part of the story; a father’s lifestyle such as diet, being overweight and stress levels have been linked to health consequences for his offspring. This occurs through the epigenome—heritable biochemical marks associated with the DNA and proteins that bind it. But how the information is transmitted at fertilization along with the exact mechanisms and molecules in sperm that are involved in this process has been unclear until now.

A new study from McGill, published recently in Developmental Cell, has made a significant advance in the field by identifying how is transmitted by non-DNA molecules in the sperm. It is a discovery that advances scientific understanding of the heredity of paternal life experiences and potentially opens new avenues for studying disease transmission and prevention.

Mar 16, 2021

Exploring complex graphs using three-dimensional quantum walks of correlated photons

Posted by in categories: biological, chemistry, information science, internet, quantum physics, space travel

Graph representations can solve complex problems in natural science, as patterns of connectivity can give rise to a magnitude of emergent phenomena. Graph-based approaches are specifically important during quantum communication, alongside quantum search algorithms in highly branched quantum networks. In a new report now published on Science Advances, Max Ehrhardt and a team of scientists in physics, experimental physics and quantum science in Germany introduced a hitherto unidentified paradigm to directly realize excitation dynamics associated with three-dimensional networks. To accomplish this, they explored the hybrid action of space and polarization degrees of freedom of photon pairs inside complex waveguide circuits. The team experimentally explored multiparticle quantum walks on complex and highly connected graphs as testbeds to pave the way to explore the potential applications of fermionic dynamics in integrated photonics.

Complex networks

Complex networks can occur across diverse fields of science, ranging from biological signaling pathways and biochemical molecules to exhibit efficient energy transport to neuromorphic circuits across to social interactions across the internet. Such structures are typically modeled using graphs whose complexity relies on the number of nodes and linkage patterns between them. The physical representation of a graph is limited by their requirement for arrangement in three-dimensional (3D) space. The human brain is a marked example of scaling behavior that is unfavorable for physical simulation due to its staggering number of 80 billion neurons, dwarfed by 100 trillion synapses that allow the flow of signals between them. Despite the number of comparably miniscule volume of nodes, discrete quantum systems faced a number of challenges owing to complex network topologies, efficient multipartite quantum communications and search algorithms.

Mar 15, 2021

Twisting, flexible crystals key to solar energy production

Posted by in categories: chemistry, solar power, sustainability

Researchers at Duke University have revealed long-hidden molecular dynamics that provide desirable properties for solar energy and heat energy applications to an exciting class of materials called halide perovskites.

A key contributor to how these materials create and transport electricity literally hinges on the way their atomic lattice twists and turns in a hinge-like fashion. The results will help materials scientists in their quest to tailor the chemical recipes of these materials for a wide range of applications in an environmentally friendly way.

The results appear online March 15 in the journal Nature Materials.

Mar 12, 2021

NASA shares first recording of Perseverance firing its laser on Mars

Posted by in categories: chemistry, space

The sounds of 30 impacts are heard, some slightly louder than others, said NASA in its press release. SuperCam, equipped with a microphone, is using the laser to interrogate the composition of rock on the red planet. The variations in the zapping sound picked up the equipment would help the scientists in understanding the physical structure of the rocks and is a key component in probing the signs of ancient life.

“Variation in the intensity of the zapping sounds will provide information on the physical structure of the targets, such as its relative hardness or the presence of weathering coatings,” said NASA.

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