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Category: chemistry – Page 255

Optical detection of multiple bacterial species using nanometer-scaled metal-organic hybrids

Osaka Metropolitan University scientists have developed a simple, rapid method to simultaneously identify multiple food poisoning bacteria, based on color differences in the scattered light by nanometer-scaled organic metal nanohybrid structures (NHs) that bind via antibodies to those bacteria. This method is a promising tool for rapidly detecting bacteria at food manufacturing sites and thereby improving food safety. The findings were published in Analytical Chemistry.

According to the World Health Organization (WHO), every year food poisoning affects 600 million people worldwide—almost 1 in every 10 people—of which 420,000 die. Bacterial tests are conducted to detect food poisoning bacteria at food manufacturing factories, but it takes more than 48 hours to obtain results due to the time required for a bacteria incubation process called culturing. Therefore, there remains a demand for rapid testing methods to eliminate food poisoning accidents.

Responding to this need, the research team led by Professor Hiroshi Shiigi at the Graduate School of Engineering, Osaka Metropolitan University, utilized the optical properties of organic metal NHs—composites consisting of polyaniline particles that encapsulate a large number of metal nanoparticles—to rapidly and simultaneously identify food poisoning-inducing bacteria called enterohemorrhagic Escherichia coli (E. coli O26 and E. coli O157) and Staphylococcus aureus.

Pulses from an atom-sharp tip enable researchers to break and form chemical bonds at will

Chemical reactions often produce messy mixtures of different products. Hence, chemists spend a lot of time coaxing their reactions to be more selective to make particular target molecules. Now, an international team of researchers has achieved that kind of selectivity by delivering voltage pulses to a single molecule through an incredibly sharp tip.

“Controlling the pathway of a chemical reaction, depending on the voltage pulses used, is unprecedented and very alluring to chemists,” says KAUST’s Shadi Fatayer.

The team used an instrument that combines scanning tunneling microscopy (STM) and (AFM). Both techniques can map out the positions of atoms within individual molecules using a tip that may be just a few atoms wide. But the voltage can also be used to break bonds within a molecule, potentially allowing new bonds to form.

Scientists Discover “Superworms” Capable of Munching Through Plastic Waste

According to the American Chemistry Council, in 2018 in the United States, 27.0 million tons of plastic ended up in landfills compared to just 3.1 million tons that were recycled. Worldwide the numbers are similarly bad, with just 9% of plastic being recycled according to a recent Organization for Economic Co-operation and Development (OECD) report.

The statistics are even worse for certain types of plastic. For example, out of 80,000 tons of styrofoam (polystyrene.

Polystyrene was discovered by accident in 1,839 by Eduard Simon, an apothecary from Berlin, Germany. As one of the most widely used plastics in the world, polystyrene is used for bottles, containers, packaging, disposable cutlery, packing peanuts, and more. It can be solid or foamed (Styrofoam is a brand name of closed-cell extruded polystyrene foam).

Simple Gene Circuits Hint at How Stem Cells Differentiate

Mathematical models suggest that with just a few more genes, it might be possible to define hundreds of cellular identities, more than enough to populate the tissues of complex organisms. It’s a finding that opens the door to experiments that could bring us closer to understanding how, eons ago, the system that builds us was built.

The Limits of Mutual Repression

Developmental biologists have illuminated many tipping points and chemical signals that prompt cells to follow one developmental pathway or another by studying natural cells. But researchers in the field of synthetic biology often take another approach, explained Michael Elowitz, a professor of biology and bioengineering at Caltech and an author of the new paper: They build a system of cell-fate control from scratch to see what it can tell us about what such systems require.

Polymorphism in metal halide perovskites

Circa 2020 This shape changing metal discovery can lead us closer to foglet machines.

Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ, USA. E-mail: [email protected]

Received 25th August 2020, Accepted 16th November 2020.

Metal halide perovskites (MHPs) are frontrunners among solution-processable materials for lightweight, large-area and flexible optoelectronics. These materials, with the general chemical formula AMX3, are structurally complex, undergoing multiple polymorph transitions as a function of temperature and pressure. In this review, we provide a detailed overview of polymorphism in three-dimensional MHPs as a function of composition, with A = Cs+, MA+, or FA+, M = Pb2+ or Sn2+, and X = Cl−, Br−, or I−. In general, perovskites adopt a highly symmetric cubic structure at elevated temperatures. With decreasing temperatures, the corner-sharing MX6 octahedra tilt with respect to one another, resulting in multiple polymorph transitions to lower-symmetry tetragonal and orthorhombic structures. The temperatures at which these phase transitions occur can be tuned via different strategies, including crystal size reduction, confinement in scaffolds and (de-)pressurization.

Why a Group of Scientists Plan to Search for Alien Technology with Avi Loeb

Why we should be performing interstellar archaeology and how Avi Loeb and his team at the Galileo Project plan to recover an interstellar object at the bottom of the ocean.

“Any chemically-propelled spacecraft sent by past civilizations into interstellar space, like the five we had sent so far (Voyager 1 & 2, Pioneer 10 & 11, and New Horizons), remained gravitationally bound to the Milky Way long after these civilizations died. Their characteristic speed of tens of kilometers per second is an order of magnitude smaller than the escape speed out of the Milky Way. These rockets would populate the Milky Way disk and move around at similar speeds to the stars in it.

This realization calls for a new research frontier of “interstellar archaeology”, in the spirit of searching our backyard of the Solar system for objects that came from the cosmic street surrounding it. The interstellar objects could potentially look different than the familiar asteroids or comets which are natural relics or Lego pieces from the construction project of the Solar system planets. The traditional field of archaeology on Earth finds relics left behind of cultures which are not around anymore. We can do the same in space.“
https://avi-loeb.medium.com/

The goal of the Galileo Project is to bring the search for extraterrestrial technological signatures of Extraterrestrial Technological Civilizations (ETCs) from accidental or anecdotal observations and legends to the mainstream of transparent, validated and systematic scientific research. This project is complementary to traditional SETI, in that it searches for physical objects, and not electromagnetic signals, associated with extraterrestrial technological equipment.

Within this overarching goal, the Galileo Project has defined two specific goals, correlating to our two related areas of study:

To examine the possibility of extraterrestrial origin for unidentified aerial phenomena (UAP), by making observations of objects in and near Earth’s atmosphere, filtering out identifiable objects using AI deep learning algorithms trained on rigorous classification of known objects, and then examining the nature of the remaining data for anomalous characteristics.

Continue reading “Why a Group of Scientists Plan to Search for Alien Technology with Avi Loeb” | >

How Vultures Can Eat Rotting Flesh Without Getting Sick

Circa 2014 😗

Vultures’ faces and large intestines are covered with bacteria that is toxic to most other creatures, but these birds of prey have evolved a strong gut that helps them not get sick from feasting on rotting flesh, according to a new study.

In the first analysis of bacteria living on vultures, the study’s researchers found that these scavengers are laden with flesh-degrading Fusobacteria and poisonous Clostridia. As bacteria decompose a dead body, they excrete toxic chemicals that make the carcass a perilous meal for most animals. But vultures often wait for decay to set in, giving them easy access to dead animals with tough skins.

Planta Sapiens

Darwin has clearly been a guiding presence in Calvo’s attempt to open up a new frontier in science: “He learned to think differently and clearly outside the frameworks in which most of his contemporaries happily confined themselves.” The result of his confinement with the cucumbers was a 118-page monograph on The Movements and Habits of Climbing Plants. Darwin realised before anyone else that these movements were in fact “behaviour”, comparable to that of animals. And observing behaviour is the route to understanding intelligence. In plants, it reveals a range of faculties “from learning and memory to competitive, risk-sensitive behaviours, and even numerical abilities”.

In the course of his book, Calvo describes many experiments that reveal plants’ remarkable range, including the way they communicate with others nearby using “chemical talk”, a language encoded in about 1,700 volatile organic compounds. He also shows how, like animals, they can be anaesthetised. In lectures, he places a Venus flytrap under a glass bell jar with a cotton pad soaked in anaesthetic. After an hour the plant no longer responds to touch by closing its traps. Tests show the plant’s electrical activity has stopped. It is effectively asleep, just as a cat would be. He also notes that the process of germination in seeds can be halted under anaesthetic. If plants can be put to sleep, does that imply they also have a waking state? Calvo thinks it does, for he argues that plants are not just “photosynthetic machines” and that it’s quite possible that they have an individual experience of the world: “They may be aware.”

Other studies show that some plants retain a memory of where the sun will rise, in order to turn their leaves towards the first rays. They store this knowledge – an internal model of what the sun is going to do – for several days, even when kept in total darkness. The conclusion must be that they constantly collect information, processing and retaining it in order to “make predictions, learn, and even plan ahead”.

New Plastic Upcycling Technology: From Waste To Fuel for Less

New technology could divert problem plastics from landfills and convert them into fuel sources.

A plastics recycling innovation that does more with less simultaneously increases conversion to useful products while using less of the precious metal ruthenium. It will be presented today (August 22, 2022) at the American Chemical Society fall meeting in Chicago.

“The key discovery we report is the very low metal load,” said Pacific Northwest National Laboratory (PNNL) chemist Janos Szanyi, who led the research team. “This makes the catalyst much cheaper.”

Your next wooden chair could arrive flat, then dry into a 3D shape

Wooden objects are usually made by sawing, carving, bending or pressing. That’s so old school! Today, scientists will describe how flat wooden shapes extruded by a 3D printer can be programmed to self-morph into complex 3D shapes. In the future, this technique could be used to make furniture or other wooden products that could be shipped flat to a destination and then dried to form the desired final shape.

The researchers will present their results at the fall meeting of the American Chemical Society (ACS).

In nature, plants and some animals can alter their own shapes or textures. Even after a tree is cut down, its wood can change shape as it dries. It shrinks unevenly and warps because of variations in fiber orientation within the wood. “Warping can be an obstacle,” says Doron Kam, a graduate student who is presenting the work at the meeting, “but we thought we could try to understand this phenomenon and harness it into a desirable morphing.”