Lifeboat Foundation

In the philosophy of mind, the multiple realizability thesis contends that a single mental kind (property, state, event) can be realized by many distinct physical kinds. A common example is pain. Many philosophers have asserted that a wide variety of physical properties, states, or events, sharing no features in common at that level of description, can all realize the same pain. This thesis served as a premise in the most influential argument against early theories that identified mental states with brain states (psychoneural, or mind-brain identity theories). It also served in early arguments for functionalism. Nonreductive physicalists later adopted this premise and these arguments (usually without alteration) to challenge all varieties of psychophysical reductionism. The argument was even used to challenge the functionalism it initially was offered to support. Reductionists (and other critics) quickly offered a number of responses, initially attacking either the anti-reductionist or anti-identity conclusion from the multiple realizability premise, or advocating accounts of the reduction relation that accommodated multiple realizability. More recently it has become fashionable to attack the multiple realizability premise itself. Most recently the first book-length treatment of multiple realizability and its philosophical import has appeared.

This entry proceeds mostly chronologically, to indicate the historical development of the topic. Its principle focus is on philosophy of mind and cognitive science, but it also indicates the more recent shift in emphasis to concerns in the metaphysics of science more generally. It is worth mentioning at the outset that multiple realizability has been claimed in physics (e.g., Batterman 2000), biochemistry (Tahko forthcoming) and synthetic biology (Koskinen 2019a, b). After more than fifty years of detailed philosophical discussion there still seems to be no end in sight for novel ideas about this persistent concern.

Two categories of nanofabrication technologies are known as top-down and bottom-up approaches [5]. For the former, nanosized materials are prepared through the rupture of bulk materials to fine particles, and such a process is usually conducted by diverse physical and mechanical techniques like lithography, laser ablation, sputtering, ball milling and arc-discharging [6, 7]. These techniques themselves are simple, and nanosized materials can be produced quickly after relatively short technological process, but expensive specialized equipment and high energy consumption are usually inevitable. Meanwhile, a variety of efficient chemical bottom-up methods, where atoms assemble into nuclei and then form nanoparticles, have been intensively studied to synthesize and modulate nanomaterials with specific shape and size [8].

Indeed, chemical methodologies, including but not limited to, aqueous reaction using chemical reducing agents (e.g. hydrazine hydrate and sodium borohydride), electrochemical deposition, hydrothermal/solvothermal synthesis, sol–gel processing, chemical liquid/vapor deposition, have been developed up to now [5, 6]. These approaches can not only produce diverse nanomaterials with fairly high yields, but also endow fine controllability in tailoring nanostructures and properties of the products. Nevertheless, they have been encountering some serious challenges of harsh reaction conditions (e.g. pH and temperature), potential risks in human health and environment, and low cost-effectiveness. Moreover, there are biosafety concerns on products synthesized chemically using hazardous reagents, which restricts their applications in many areas, particularly in medicines and pharmaceuticals [9].

Impressively, biological methodology is becoming a favourite in nanomaterial synthesis nowadays to address challenges in chemical synthesis. Compared to chemical routes, biosynthesis using natural and biological materials as reducing, stabilizing and capping agents are simple, energy-and cost-effective, mild and environment-friendly, which is termed as “Green Chemistry” [2, 6]. More significantly, the biologically synthesized nanomaterials have much better competitiveness in biocompatibility, compared to those chemically derived counterparts. On the one hand, the biogenic nanomaterials are free from toxic contamination of by-products that are usually involved in chemical synthesis process; on the other hand, the biosynthesis do not need additional stabilizing agents because either the used organisms themselves or their constituents can act as capping and stabilizing agents and the attached biological components in turn form biocompatible envelopes on the resultant nanomaterials, leading to actively interact with biological systems [2]. As one of the most abundant biological resources, some microorganisms have adapted to habitat contaminated with toxic metals, and thus evolved powerful tactics for remediating polluted environment while recycling metal resources [7, 10], and some review articles on the biosynthesis of MNPs using diverse microorganisms including bacteria, yeast, fungi, alga, etc. and their applications have been published in recent years [1, 2, 6, 7, 10].

Researchers around the world are on a mission to relieve a bottleneck in the clean energy revolution: batteries. From electric vehicles to renewable grid-scale energy storage, batteries are at the heart of society’s most crucial green innovations—but they need to pack more energy to make these technologies widespread and practical.

Now, a team of scientists led by chemists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Pacific Northwest National Laboratory (PNNL) has unraveled the complex chemical mechanisms of a battery component that is crucial for boosting energy density: the interphase. Their work published today in Nature Nanotechnology.

UV tattoos use a fluorescent dye, which means the tattoo only appears under UV light. There is little evidence on whether UV tattoos are safe for human skin.

UV tattoos, also known as black light tattoos, are invisible under regular lighting and only appear under UV light due to the fluorescent compounds within the ink.

There is no regulation over UV tattoos, so there may be some potential health risks, depending on the ink’s chemicals. UV tattoos will also require similar aftercare to regular tattoos.

Examinations using microscopes confirmed that these neurons were active in the mice with chronic pain. When the researchers used chemicals to stop the neuronal activity in this cortex, the mice’s appetites improved.

Similarly, when the researchers used chemicals to activate these neurons in mice that weren’t in pain, the animals ate less, even if they had been deprived of food before the experiment.

This is the first time that researchers have traced the brain mechanisms behind pain-related appetite loss, the researchers wrote.

Excess fat triggers immune cells to overeat serotonin in the brain of developing male mice, leading to depression-like behavior. More than half of all women in the United States are overweight or obese when they become pregnant. While being or becoming overweight during pregnancy can have potential health risks for moms, there are also hints that it may tip the scales for their kids to develop psychiatric disorders like autism or depression, which often affects one gender more than the other.

What hasn’t been understood however is how the accumulation of fat tissue in mom might signal through the placenta in a sex-specific way and rearrange the developing offspring’s brain.

To fill this gap, Duke postdoctoral researcher Alexis Ceasrine, Ph.D., and her team in the lab of Duke psychology & neuroscience professor Staci Bilbo, Ph.D., studied pregnant mice on a high-fat diet. In findings appearing November 28 in the journal Nature Metabolism, they found that mom’s high-fat diet triggers immune cells in the developing brains of male but not female mouse pups to overconsume the mood-influencing brain chemical serotonin, leading to depressed-like behavior.

A study in the journal Human Reproduction finds that human sperm counts fell by 62% in the last 50 years, possibly a result of poor diets and a toxic soup of forever chemicals in air and water.

Engineers at Caltech have developed a method for 3D printing pure and multicomponent metals, at a resolution that is, in some cases, an order of magnitude smaller than previously possible. The process, which uses water-based chemistry and 3D printing, was described in a paper published in Nature on October 20.

Year 2011 face_with_colon_three

Ultrafast science has begun to tackle the measurement of electronic and chemical processes taking place on the few-femtosecond-to-attosecond timescale. This field requires high-power, extremely short-duration laser pulses. Here we review progress towards the generation of such pulses by Raman scattering in a medium whose component molecules oscillate in phase, which modulates the optical polarizability of the medium and generates high-order Raman sidebands on a field propagating through it. This process may occur with high efficiency and thus lead to sufficient bandwidth for supporting few-femtosecond to attosecond pulses. Significant progress has recently been made in the use of this technique to deliver useable ultrashort pulses in the visible to ultraviolet regions of the spectrum.