Tag Archives: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Georges Canguilhem’s influence on life sciences philosophy and ‘it’s all about Kant’

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This July 5, 2023 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) press release by José Tadeu Arantes (also on EurekAlert but published on July 3, 2023) slow walks us through a listing of French intellectuals and some history (which I enjoyed) before making a revelation,

The constitution of the World Health Organization (WHO) defines health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity”. The definition dates from the 1940s, but even then the thinking behind it was hardly novel. Similar concepts can be found in antiquity, in Eastern as well as Western societies, but in Europe, the cradle of Western culture, the view that mental well-being was part of health enjoyed little prestige in the eighteenth and nineteenth centuries owing to a reductionist understanding of disease as strictly somatic (relating only to the body). This outlook eventually began to be questioned. One of its leading critics in the twentieth century was French philosopher and physician Georges Canguilhem (1904-1995).

A disciple of Gaston Bachelard (1884-1962), a colleague of Jean-Paul Sartre (1905-1980), Paul Nizan (1905-1940) and Raymond Aron (1905-1983), and a major influence on Michel Foucault (1926-1984), Canguilhem was one of the foremost French intellectuals of the postwar years. Jacques Lacan (1901-1981), Gilles Deleuze (1925-1995) and Jacques Derrida (1930-2004) were among the thinkers who took inspiration from his ideas.

Canguilhem began studying medicine in the mid-thirties and earned his medical doctorate in 1943, by which time he had already taught philosophy in high schools for many years (having qualified in 1927). Another significant tack in his life course occurred during World War Two. He had long been both a pacifist and an antifascist. Following the French surrender in 1940, he refused to continue teaching under the Vichy regime and joined the Resistance, fighting with the rural guerrillas of the Maquis. In this historically and politically complex period, he apparently set out to train as a physician in order to have practical experience as well as book learning and to work on the history of the life sciences. He was awarded the Croix de Guerre and the Médaille da la Résistance for organizing a field hospital while under attack in the Auvergne.

In an article published in the journal History and Philosophy of the Life Sciences, Emiliano Sfara, who has a PhD in philosophy from the University of Montpellier and was a postdoctoral fellow at the University of São Paulo (USP) in Brazil from 2018 to 2022, argues that Canguilhem’s concepts of “technique”, “technical activity” and “practice” derived from Immanuel Kant’s Critique of Judgment (1790) and influenced Canguilhem’s decision to study medicine.

“Earlier historiographical research showed how Kant influenced Canguilhem, especially the concept of ‘knowledge’ developed in Kant’s Critique of Pure Reason as the unification of heterogeneous data by an organizing intellect, and the idea of the ‘organism’ as a totality of interdependent and interacting parts, inspired by the Critique of Judgment. I tried to show in the article the importance, and roots in Kant, of a third cluster of ideas relating to the concept of ‘technique’ in Canguilhem’s work, beginning in mid-thirties,” said Sfara, currently a researcher at the National Institute of Science and Technology for Interdisciplinary and Transdisciplinary Studies in Ecology and Evolution (INCT IN-TREE), hosted by the Federal University of Bahia (UFBA).

“Section 43 of Kant’s Critique of Judgment makes a distinction between technical capacity and science as a theoretical faculty. Technique is the subject’s concrete practice operating in a certain context, a vital movement of construction or manufacturing of objects and tools that enable a person to live in their environment. This is not reducible to science. Analogously, Canguilhem postulates that science is posterior to technique. Practice comes first; theory arises later. This movement is evident in art. True, the artist starts out with a project. But the development of the artwork isn’t confined to the project, which is reconstructed as the process unfolds. This practical element of the subject’s interaction with the environment, which has its roots in Kant’s theories, was very important to the evolution of Canguilhem’s thought. It even influenced his decision to study medicine, as well as the conception of medicine he developed.”

Sfara explained that while Canguilhem espoused the values of the Parti Radical in his youth, in the mid-thirties he moved left, without becoming a pro-Soviet Stalinist. Later on, according to some scholars who knew him and are still active (such as the Moroccan philosopher and mathematician Hourya Benis Sinaceur), Canguilhem gave primacy to the egalitarian principles symbolized by the French Republic’s motto Liberté, Egalité, Fraternité.

His main contributions were to medicine and philosophy of science. His most important work, The Normal and the Pathological (1966), is basically an expansion of his 1943 doctoral thesis. “In his original thesis, Canguilhem broke with part of eighteenth- and nineteenth-century French medical tradition and formulated ideas that are very much part of medicine today. [emphasis mine] Taking a purely analytical and quantitative approach, physicians like François Broussais (1772-1838) believed disease resulted from a surplus or lack of some organic substance, such as blood. Bloodletting was regularly used as a form of treatment. France imported 33 million leeches from southern Europe in the first half of the nineteenth century. Canguilhem saw the organism as a totality that interacted with its environment [emphasis mine] rather than a mere aggregation of parts whose functioning depended only on a ‘normal’ amount of the right organic substances,” Safra said.

In Canguilhem, the movement changes. Instead of transiting from the part to the whole, he moves from the whole to the part (as does Kant in the Critique of Judgment). He views the organism not as a machine but as an integral self-regulating totality. Life cannot be deduced from physical and chemical laws. One must start from the living being to understand life. Practice is the bridge that connects this totality to the environment. At the same time as it changes the environment, practice changes the organism and helps determine its physiological states.

“So Canguilhem implies that in order to find a state called normal, i.e. healthy, a given organism has to adapt its own operating rules to the outside world in the course of interacting concretely and practically with the environment. A human organism, for example, is in a ‘normal’ state when its pulse slows sharply after a period of long daily running. A case in point is the long-distance runner, who has to train every day,” Safra said.

“For Canguilhem, disease is due to inadaptation between the part, the organism and the environment, and often manifests itself as a feeling of malaise. Adaptive mechanisms in the organism can correct pathological dysfunctions.”

The article resulted from Sfara’s postdoctoral research supervised by Márcio Suzuki and supported by FAPESP.

The article “From technique to normativity: the influence of Kant on Georges Canguilhem’s philosophy of life” is at: link.springer.com/article/10.1007/s40656-023-00573-8.

This text was originally published by FAPESP Agency according to Creative Commons license CC-BY-NC-ND. Read the original here.https://agencia.fapesp.br/republicacao_frame?url=https://agencia.fapesp.br/study-shows-kants-influence-on-georges-canguilhem-who-anticipated-concepts-current-in-medicine-today/41794/&utm_source=republish&utm_medium=republish&utm_content=https://agencia.fapesp.br/study-shows-kants-influence-on-georges-canguilhem-who-anticipated-concepts-current-in-medicine-today/41794/

Even though you can find a link to the paper in the press release, here’s my version of a citation complete with link,

From technique to normativity: the influence of Kant on Georges Canguilhem’s philosophy of life by Emiliano Sfara .History and Philosophy of the Life Sciences volume 45, Article number: 16 (2023) DOI: https://doi.org/10.1007/s40656-023-00573-8 Published: 06 April 2023

This paper is open access.

Adding as little as 0.1% of rosmarinic acid reduced amount of sunscreen needed to protect skin and more

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Since metallic nanoparticles are now pretty much accepted as being relatively safe ingredients, I don’t write about sunscreens very often anymore. Of course metallic nanoparticles had to be rebranded as ‘minerals’ after some civil society groups raised a great fuss. (See my February 9, 2012 posting “Unintended consequences: Australians not using sunscreens to avoid nanoparticles?” for a rundown of the situation.)

This April 5, 2023 news item about a different kind of sunscreen ingredient on phys.org caught my eye,

An article published in the journal Cosmetics reports an investigation of the effects of including rosmarinic acid, an active antioxidant, in a sunscreen along with two conventional ultraviolet light filters, ethylhexyl methoxycinnamate (against UVB) and avobenzone (against UVA).

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They don’t seem to have tested this new ingredient in any ‘mineral’ sunscreens but it seems an intriguing possibility. Here’s more about rosmarinic acid and why it may be a good addition to sunscreens from an April 5, 2023 Fundação de Amparo à Pesquisa do Estado de São Paulo (São Paulo Research Foundation; FAPESP) press release (also on EurekAlert), which originated the news item, Note: Links have been removed)

The research group increased the sunscreen’s photoprotective efficacy by adding rosmarinic acid at 0.1%, a very small proportion compared with those of conventional UV filters. They believe their findings suggest that incorporating natural molecules with antioxidant activities into sunscreens could decrease the proportion of conventional UV filters in the final product, with the advantage of providing other functional properties.

The product’s performance improved without the need to increase active principle levels, reducing both the amount of sunscreen needed to protect the same skin area and the volume of synthetic chemicals discharged into the environment.

In vitro and clinical trials obtained a 41% increase in sun protection factor (SPF). The higher the SPF, the more sunburn protection increases.

Another advantage of including rosmarinic acid was the addition of antioxidant activity to photoprotection so that the product could be used in antiaging cosmetics, for example.

“Our research on photoprotective systems aims primarily to evaluate potential sunscreen enhancement strategies. We’re interested above all in discovering ways to increase sunburn protection while also improving the stability of the product so that it remains safe and effective for longer,” said pharmaceutical scientist and biochemist André Rolim Baby, last author of the article and a professor at the University of São Paulo’s School of Pharmaceutical Sciences (FCF-USP) in Brazil.

“We’re also looking for products or systems with less environmental impact and ways of reducing the concentration of conventional filters by including natural ingredients that enhance the formulation. And we’re very interested in mapping other cosmetic properties of photoprotective molecules, such as anti-free radical action and protection of biomarkers in the outermost skin layers.”

Multifunctional compound

The investigation was part of a project supported by FAPESP to map chemopreventive properties of various UV filters.

In addition to being an antioxidant, rosmarinic acid, a natural polyphenol antioxidant found in rosemary, as well as sage, peppermint and many other herbal plants, has antiviral, anti-inflammatory, immunomodulatory, antibiotic and anticancer properties.

In a review article published in 2022 in the journal Nutrients, the research group highlighted the beneficial effects of rosmarinic acid as a food supplement, such as improvement in skin firmness and wrinkle reduction.

“In another investigation, we found potential benefits of rosmarinic acid for skin surface hydration, reinforcing the need for more research on the substance in the field of cosmetology,” Baby said.

…

Here’s a link to and a citation for the research team’s latest paper,

Photoprotective Efficacy of the Association of Rosmarinic Acid 0.1% with Ethylhexyl Methoxycinnamate and Avobenzone by Maíra de Oliveira Bispo, Ana Lucía Morocho-Jácome, Cassiano Carlos Escudeiro, Renata Miliani Martinez, Claudinéia Aparecida Sales de Oliveira Pinto, Catarina Rosado, Maria Valéria Robles Velasco and André Rolim Baby. Cosmetics 2023, 10(1), 11; https://doi.org/10.3390/cosmetics10010011 Published: 5 January 2023 (This article belongs to the Special Issue Feature Papers in Cosmetics in 2022)

This paper is open access.

Cellulose nanofibrils for slow-release fertilizer

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An October 17, 2022 news item on phys.org highlights nanocellulose research from Brazil, Note: A link has been removed,

A research team affiliated with the Laboratory of Polymeric Materials and Biosorbents at the Federal University of São Carlos (UFSCar) in Araras, São Paulo state, Brazil, has produced and is testing cellulose-based materials for enhanced-efficiency fertilizers to improve the supply of nutrients to crops and reduce the release of non-biodegradable chemicals [forever chemicals] into the ecosystem.

The studies were led by Roselena Faez, a professor at the Center for Agricultural Sciences (CCA-UFSCar). The findings have recently been reported in two publications. One is an article published in Carbohydrate Polymers, with Débora França as first author. Here [keep scrolling down] the researchers describe how they used modified nanocellulose to discharge the nutrients contained in fertilizer into the soil slowly and in a controlled manner, given that nitrogen, phosphorus and potassium are highly soluble.

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Caption: The first and third photos show the paper made from phosphorylated sugarcane cellulose. The second shows the 3D structure of the material comprising cellulose and nutrient. The fourth shows the microparticles in powder form and after molding into tablets. Credit: Lucas Luiz Messa/Débora França

An October 19, 2022 Fundação de Amparo à Pesquisa do Estado de São Paulo [FAPESP] press release (also on EurekAlert but published October 17, 2022) by Karina Ninni, originated the phys.org news item. The researchers explain (Note: Links have been removed),

“Potassium is rapidly washed away by rain because of its high ion mobility. It’s the hardest to release in a controlled manner. Nitrogen can be obtained from various sources, such as nitrates, ammonia and urea, but plants get the nitrogen they need most easily from nitrate, which is also easily washed away and doesn’t remain in the soil for long. Phosphorus [as phosphate] is a very large ion and less mobile than the other macronutrients,” said Faez, who coordinates the Polymeric Materials and Biosorbents Research Group at UFSCar Araras.

Controlled-release products are available on the market, she added, but most are made of synthetic polymers, which are non-biodegradable. “Fertilizer grains are about the size of grains of coarse sea salt. To make sure the nutrients are released slowly, they’re coated with layers of polymer that last about two months each, so the manufacturer applies two, three or four coats, according to the desired length of time for controlled release,” Faez explained, noting that the polymers in question are plastics and remain in the soil, eventually degrading into microparticles that last virtually forever.

The researchers at UFSCar developed an entirely different product in which the chemical reaction between the modified nanocellulose and mineral salts keeps the nutrients in the soil. “We focused on the worst problems, which are nitrate and potassium. The material we developed is totally biodegradable and releases these nutrients at about the same slow rate as the available synthetic materials,” Faez said.

The nanocellulose was obtained from pure cellulose donated by a paper factory. The nanofibrils were functionalized with positive and negative charges to enhance polymer-nutrient interaction. “Because the salts are also made up of positively or negatively charged particles and highly soluble, we hypothesized that negatively charged nanocellulose would react with positive ions in the salts, while positively charged nanocellulose would interact with negative ions, reducing the solubility of the salts. This proved to be the case, and the group succeeded in modulating nutrient release in accordance with the type of particle in the material,” França said.

Evaluation in soil

The group fabricated the product in the form of tablets and evaluated its performance in terms of nutrient release into the soil. Evaluation of release into water is the usual method, and water is a very different system from soil. This part of the research was conducted in partnership with Claudinei Fonseca Souza, a professor at CCA-UFSCar’s Department of Natural Resources and Environmental Protection in Araras.

“We evaluated nutrient release into the soil and biodegradation of the material at the site for 100 days. But we deliberately used very poor soil with little organic matter, because this enables us to see the physical effects of release more easily,” Faez said.

The researchers used two techniques to obtain tablets: atomization and spray drying to encapsulate the nutrients with the nanocellulose, followed by heat processing of the resulting powder, which was pressed in a mold. This work was completed with the help of colleagues at the Cellulose and Wood Materials Laboratory belonging to EMPA (Swiss Federal Laboratories for Materials Science and Technology) and in collaboration with UFSCar’s Water, Soil and Environment Engineering Research Group, led by Souza. França performed the cellulose modifications at EMPA while on an internship there with support from FAPESP. She was also supported by a doctoral scholarship in Brazil.

Self-fertilization

The second recent article by the group was published in Industrial Crops and Products, with chemist Lucas Luiz Messa as first author. The goal of the study was to extract cellulose from sugarcane bagasse and modify it with a surface negative charge by phosphorylation (addition of a phosphorus group) to allow controlled release of potassium. In theory, delivery of plant nutrition would be slowed by cellulose phosphorylation, which would create surface anionic charges that would bind to macronutrient and micronutrient cations. 

The group prepared three types of structure with the phosphorylated cellulose: oven-dried paper-like film; spray-dried powder; and freeze-dried porous bulk similar to polystyrene foam. Freeze drying, or lyophilization, was seen to leave nutrients in the voids left by water removal. 

“Technologically speaking, the paper-like structure was the best material we produced for controlled delivery of nutrients. Several products can be created using this paper,” Faez said.

The results obtained in the research led by Messa enabled the group to develop small propagation pots for seedling cultivation. When this material degrades, the phosphorus it contains is released. According to Faez, cellulose phosphorylation is cheap, and the cost of the end product is relatively low. “It’s more or less BRL 0.27 per gram of paper produced. The propagation pot must be about 1 gram. Unit cost is therefore about BRL 0.30 in terms of laboratory costs,” she said.

Biodegradable propagation pots are already available on the market. “But our product has built-in fertilizer, which is a major competitive advantage. Indeed, we’ve filed a patent application,” she said.

The pot is about to be trialed by a flower producer in Holambra, São Paulo state. Several batches produced in the laboratory have been shipped there. Nutrient release has so far been tested only in water. “We call this an accelerated ion release assessment method because it’s faster in water, but even in water we found the release rate to be 40%-50% slower compared with the behavior of the ion in the material and without the material. Even in water, therefore, we succeeded in retaining these ions. We assume delivery will be even slower in the substrate,” she said.

The research was also supported by FAPESP via a Doctoral Scholarship in Brazil and a Research Internship Abroad Scholarship awarded to Messa, and a Regular Research Grant awarded to Faez.

Messa was assisted by a colleague at the University of California Davis (USA), where he worked as a research intern.

About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe

I have links and citations for both papers mentioned in the press release,

Sugarcane bagasse derived phosphorylated cellulose as substrates for potassium release induced by phosphates surface and drying methods by Lucas Luiz Messa, You-Lo Hsieh, Roselena Faez. Industrial Crops and Products Volume 187, Part A, 1 November 2022, 115350 DOI: https://doi.org/10.1016/j.indcrop.2022.115350 Available online 20 July 2022, Version of Record 20 July 2022

This paper is behind a paywall.

Charged-cellulose nanofibrils as a nutrient carrier in biodegradable polymers for enhanced efficiency fertilizers by Débora França, Gilberto Siqueira, Gustav Nyström, Frank Clemens, Claudinei Fonseca Souza, Roselena Faez. Carbohydrate Polymers Volume 296, 15 November 2022, 119934 DOI: https://doi.org/10.1016/j.carbpol.2022.119934 Available online 1 August 2022, Version of Record 3 August 2022

This paper is behind a paywall.

Mystery of North American insect bioluminescent systems unraveled by Brazilian scientists

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I’ve always been fond of ‘l’ words and so it is that I’m compelled to post a story about a “luciferin-luciferase system” or, in this case, a story about insect bioluminescence.

Caption: Researchers isolated molecules present in the larvae of the fungus gnat Orfelia fultoni Credit: Vadim Viviani, UFSCar

A September 9, 2020 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) press release (also on EurekAlert but published Sept. 11, 2020) announces research into ‘blue’ bioluminescence,

Molecules belonging to an almost unknown bioluminescent system found in larvae of the fungus gnat Orfelia fultoni (subfamily Keroplatinae) have been isolated for the first time by researchers at the Federal University of São Carlos (UFSCar) in the state of São Paulo, Brazil. The small fly is one of the few terrestrial organisms that produce blue light. It inhabits riverbanks in the Appalachian Mountains in the eastern United States. A key part of its bioluminescent system is a molecule also present in two recently discovered Brazilian flies.

The study, supported by Paulo Research Foundation – FAPESP, is published in Scientific Reports. Five authors are affiliated with UFSCar and two with universities in the United States.

The bioluminescent systems of glow-worms, fireflies and other insects are normally made up of luciferin (a low molecular weight molecule) and luciferase, an enzyme that catalyzes the oxidation of luciferin by oxygen, producing light. While some bioluminescent systems are well known and even used in biotechnological applications, others are poorly understood, including blue light-emitting systems, such as that of O. fultoni.

“In the published paper, we describe the properties of the insect’s luciferase and luciferin and their anatomical location in its larvae. We also specify several possible proteins that are possible candidates for the luciferase. We don’t yet know what type of protein it is, but it’s likely to be a hexamerin. In insects, hexamerins are storage proteins that provide amino acids, besides having other functions, such as binding low molecular weight compounds, like luciferin,” said Vadim Viviani, a professor in UFSCar’s Sustainability Science and Technology Center (CCTS) in Sorocaba, São Paulo, and principal investigator for the study.

The study was part of the FAPESP-funded project “Arthropod bioluminescence“. The partnership with United States-based researchers dates from a previous project, supported by FAPESP and the United States National Science Foundation (NSF), in partnership with Vanderbilt University (VU), located in Nashville, Tennessee.

In addition to luciferin and luciferase, researchers began characterizing a complex found in insects of the family Keroplatidae, which, in addition to O. fultoni, also includes a Brazilian species in the genus Neoditomyia that produces only luciferin and hence does not emit light.

Because they do not use it to emit light, the luciferin in O. fultoni and the Brazilian Neoditomyia has been named keroplatin. In larvae of this subfamily, keroplatin is associated with “black bodies” – large cells containing dark granules, proteins and probably mitochondria (energy-producing organelles). Researchers are still investigating the biological significance of this association between keroplatin and mitochondria.

“It’s a mystery,” Viviani said. “This luciferin may play a role in the mitochondrial energy metabolism. At night, probably in the presence of a natural chemical reducer, the luciferin is released by these black bodies and reacts with the surrounding luciferase to produce blue light. These are possibilities we plan to study.”

Brazilian cousins

An important factor in the elucidation of the United States insect’s bioluminescent system was the discovery of a larva that lives in Intervales State Park in São Paulo in 2018. It does not emit light but produces luciferin, similar to O. fultoni (read more at: agencia.fapesp.br/29066).

In their latest study, the group injected purified luciferase from the United States species into larvae of the Brazilian species, which then produced blue light. The nonluminescent Brazilian species is more abundant in nature than the United States species, so a larger amount of the material could be obtained for study purposes, especially to characterize the luciferin (keroplatin) present in both species.

In 2019, the group discovered and described Neoceroplatus betaryensis, a new species of fungus gnat, in collaboration with Cassius Stevani, a professor at the University of São Paulo’s Institute of Chemistry (IQ-USP). It was the first blue light-emitting insect found in South America and was detected in a privately held forest reserve near the Upper Ribeira State Tourist Park (PETAR) in the southern portion of the state of São Paulo. A close relative of O. fultoni, N. betaryensis inhabits fallen tree trunks in humid places (read more at: agencia.fapesp.br/31797).

“We show that the bioluminescent system of this Brazilian species is identical to that of O. fultoni. However, the insect is very rare, and so it’s hard to obtain sufficient material for research purposes,” Viviani said.

The researchers are now cloning the insect’s luciferase and characterizing it in molecular terms. They are also analyzing the chemical structure of its luciferin and the morphology of its lanterns.

“Once all this has been determined, we’ll be able to synthesize the luciferin and luciferase in the lab and use these systems in a range of biotech applications, such as studying cells. This will help us understand more about human diseases, among other things,” Viviani said.

Here’s a link to and a citation for the paper,

A new brilliantly blue-emitting luciferin-luciferase system from Orfelia fultoni and Keroplatinae (Diptera) by Vadim R. Viviani, Jaqueline R. Silva, Danilo T. Amaral, Vanessa R. Bevilaqua, Fabio C. Abdalla, Bruce R. Branchini & Carl H. Johnson. Scientific Reports volume 10, Article number: 9608 (2020) DOI: https://doi.org/10.1038/s41598-020-66286-1 Published 15 June 2020

This paper is open access.

Optical fibers made from marine algae

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Apparently after you’ve finished imaging with your marine algae-based optical fibers, you can eat them. A July 24, 2020 news item on Nanowerk announces the new research,

An optical fiber made of agar has been produced at the University of Campinas (UNICAMP) in the state of São Paulo, Brazil. This device is edible, biocompatible and biodegradable. It can be used in vivo for body structure imaging, localized light delivery in phototherapy or optogenetics (e.g., stimulating neurons with light to study neural circuits in a living brain), and localized drug delivery.

Another possible application is the detection of microorganisms in specific organs, in which case the probe would be completely absorbed by the body after performing its function.

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Caption: Edible, biocompatible and biodegradable, these fibers have potential for various medical applications. Credit: Eric Fujiwara

A July 24, 2020 Fundação de Amparo à Pesquisa dFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) do Estado de São Paulo press release on EurekAlert, which originated the news item, provides a few more details about the researches and the work,

The research project, which was supported by São Paulo Research Foundation – FAPESP, was led by Eric Fujiwara, a professor in UNICAMP’s School of Mechanical Engineering, and Cristiano Cordeiro, a professor in UNICAMP’s Gleb Wataghin Institute of Physics, in collaboration with Hiromasa Oku, a professor at Gunma University in Japan.

An article on the study is published) in Scientific Reports, an online journal owned by Springer Nature.

Agar, also called agar-agar, is a natural gelatin obtained from marine algae. Its composition consists of a mixture of two polysaccharides, agarose and agaropectin. “Our optical fiber is an agar cylinder with an external diameter of 2.5 millimeters [mm] and a regular inner arrangement of six 0.5 mm cylindrical airholes around a solid core. Light is confined owing to the difference between the refraction indices of the agar core and the airholes,” Fujiwara told.

“To produce the fiber, we poured food-grade agar into a mold with six internal rods placed lengthwise around the main axis,” he continued. “The gel distributes itself to fill the available space. After cooling, the rods are removed to form airholes, and the solidified waveguide is released from the mold. The refraction index and geometry of the fiber can be adapted by varying the composition of the agar solution and mold design, respectively.”

The researchers tested the fiber in different media, from air and water to ethanol and acetone, concluding that it is context-sensitive. “The fact that the gel undergoes structural changes in response to variations in temperature, humidity and pH makes the fiber suitable for optical sensing,” Fujiwara said.

Another promising application is its simultaneous use as an optical sensor and a growth medium for microorganisms. “In this case, the waveguide can be designed as a disposable sample unit containing the necessary nutrients. The immobilized cells in the device would be optically sensed, and the signal would be analyzed using a camera or spectrometer,” he said.

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About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at http://www.fapesp.br/en and visit FAPESP news agency at http://www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.

As per my usual practice, here’s a link to and a citation for the paper,

Agarose-based structured optical fibre by Eric Fujiwara, Thiago D. Cabral, Miko Sato, Hiromasa Oku & Cristiano M. B. Cordeiro. Scientific Reports volume 10, Article number: 7035 (2020) DOI: https://doi.org/10.1038/s41598-020-64103-3 Published: 27 April 2020

This paper is open access.

Should you have a problem accessing the English language version of the FAPESP website, the Portuguese language version of the site seems more accessible (assuming you have the language skills).

Proposed nanodevice made possible by particle that is its own antiparticle (Majorana particle)

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I’m not sure how much the mystery of Ettore Majorana’s disappearance in 1938 has to do with the latest research from Brazil on Majorana particles but it’s definitely fascinating,. From an April 6, 2018 news item on ScienceDaily,

In March 1938, the young Italian physicist Ettore Majorana disappeared mysteriously, leaving his country’s scientific community shaken. The episode remains unexplained, despite Leonardo Scascia’s attempt to unravel the enigma in his book The Disappearance of Majorana (1975).

Majorana, whom Enrico Fermi called a genius of Isaac Newton’s stature, vanished a year after making his main contribution to science. In 1937, when he was only 30, Majorana hypothesized a particle that is its own anti-particle and suggested that it might be the neutrino, whose existence had recently been predicted by Fermi and Wolfgang Pauli.

Eight decades later, Majorana fermions, or simply majoranas, are among the objects most studied by physicists. In addition to neutrinos — whose nature, whether or not they are majoranas, is one of the investigative goals of the mega-experiment Dune — another class not of fundamental particles but of quasi-particles or apparent particles has been investigated in the field of condensed matter. These Majorana quasi-particles can emerge as excitations in topological superconductors.

An April 6, 2018 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) press release on EurekAlert, which originated the news item,  reveals more about the Brazilian research (Note: Links have been removed),

A new study by PhD student Luciano Henrique Siliano Ricco with a scholarship from the São Paulo Research Foundation – FAPESP, in collaboration with his supervisor Antonio Carlos Ferreira Seridonio and others, was conducted on the Ilha Solteira campus of São Paulo State University (UNESP) in Brazil and described in an article in Scientific Reports.

“We propose a theoretical device that acts as a thermoelectric tuner – a tuner of heat and charge – assisted by Majorana fermions,” Seridonio said.

The device consists of a quantum dot (QD), represented in the Figure A by the symbol ε1. QDs are often called “artificial atoms.” In this case, the QD is located between two metallic leads at different temperatures.

The temperature difference is fundamental to allowing thermal energy to flow across the QD. A quasi-one-dimensional superconducting wire – called a Kitaev wire after its proponent, Russian physicist Alexei Kitaev, currently a professor at the California Institute of Technology (Caltech) in the US – is connected to the QD.

In this study, the Kitaev wire was ring- or U-shaped and had two majoranas (η1 and η2) at its edges. The majoranas emerge as excitations characterized by zero-energy modes.

“When the QD is coupled to only one side of the wire, the system behaves resonantly with regard to electrical and thermal conductance. In other words, it behaves like a thermoelectric filter,” said the principal investigator for the FAPESP fellowship.

“I should stress that this behavior as a filter for thermal and electrical energy occurs when the two majoranas ‘see’ each other via the wire, but only one of them ‘sees’ the QD in the connection.”

Another possibility investigated by the researchers involved making the QD “see” the two majoranas at the same time by connecting it to both ends of the Kitaev wire.

“By making the QD ‘see’ more of η1 or η2, i.e., by varying the system’s asymmetry, we can use the artificial atom as a tuner, where the thermal or electrical energy that flows through it is redshifted or blueshifted,” Seridonio said (see Figure B for illustrative explanation).

This theoretical paper, he added, is expected to contribute to the development of thermoelectric devices based on Majorana fermions.

Here’s a link to and a citation for the paper,

Tuning of heat and charge transport by Majorana fermions by L. S. Ricco, F. A. Dessotti, I. A. Shelykh, M. S. Figueira & A. C. Seridonio. Scientific Reportsvolume 8, Article number: 2790 (2018) doi:10.1038/s41598-018-21180-9 Published online: 12 February 2018

This paper is open access.

As I prepared to publish this piece I stumbled across a sad Sept. 3, 2018 article about Brazil and its overnight loss of heritage in a fire by Henry Grabar for slate.com (Note: Links have been removed),

On Sunday night, a fire ripped through Brazil’s National Museum in Rio de Janeiro, destroying the country’s most valuable storehouse of natural and anthropological history within hours.

Most of the 20 million items housed inside—including the skull of Luzia, the oldest human remains ever found in the Americas; one of the world’s largest archives of South America’s indigenous cultures; more than 26,000 fossils, 55,000 stuffed birds, and 5 million insect specimens; and a library of more than 500,000 books—are thought to have been destroyed.

…

The loss is a symptom of a larger problem as Grabar notes in his article.

Measurably fewer nanoparticles in São Paulo’s (Brazil) air after ethanol use

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An Aug. 28, 2017 news item on Nanotechnology Now features news about nanoparticles and the environment in São Paulo, Brazil,

When ethanol prices at the pump rise for whatever reason, it becomes economically advantageous for drivers of dual-fuel vehicles to fill up with gasoline. However, the health of the entire population pays a high price: substitution of gasoline for ethanol leads to a 30% increase in the atmospheric concentration of ultrafine particulate matter, which consists of particles with a diameter of less than 50 nanometers (nm).

An Aug. 23, 2017 Fundação de Amparo à Pesquisa do Estado de São Paulo (The São Paulo Research Foundation [FAPESP]) press release, which originated the news item, explains further,

The phenomenon was detected in São Paulo City, Brazil, in a study supported by FAPESP and published in July 2017 in Nature Communications.

“These polluting nanoparticles are so tiny that they behave like gas molecules. When inhaled, they can penetrate the respiratory system’s defensive barriers and reach the pulmonary alveoli, so that potentially toxic substances enter the bloodstream and may increase the incidence of respiratory and cardiovascular problems,” said Paulo Artaxo, Full Professor at the University of São Paulo’s Physics Institute (IF-USP) and a co-author of the study.

Levels of ultrafine particulate matter in the atmosphere are neither monitored nor regulated by environmental agencies not only in Brazil but practically anywhere in the world, according to Artaxo. The São Paulo State Environmental Corporation (CETESB), for example, routinely monitors only solid particles with diameters of 10,000 nm (PM10) and 2,500 nm (PM2.5) – as well as other gaseous pollutants such as ozone (O3), carbon monoxide (CO) and nitrogen dioxide (NO2).

“Between 75% and 80% of the mass of the nanoparticles we measured in this study corresponds to organic compounds emitted by motor vehicles – carbon in different chemical forms. What these compounds are exactly and how they affect health are questions that require further research,” Artaxo said.

He added that a consensus is forming in the United States and Europe based on recent research indicating that these emissions are a potential health hazard and should be regulated. Several US states, such as California, have laws requiring a 20%-30% ethanol blend in gasoline, which also helps reduce emissions of ultrafine particulate matter.

Methodology

The data analyzed in the study were collected during the period of January-May 2011, when ethanol prices fluctuated sharply compared with gasoline prices, owing to macroeconomic factors such as variations in the international price of sugar (Brazilian ethanol is made from sugarcane).

Collection was performed at the top of a ten-story building belonging to IF-USP in the western part of São Paulo City. According to Artaxo, the site was chosen because it is relatively distant from the main traffic thoroughfares so that the aerosols there are “older” in the sense that they have already interacted with other substances present in the atmosphere.

“Generally speaking, the pollution we inhale every day at home or at work isn’t what comes out of vehicular exhaust pipes but particles already processed in the atmosphere,” he explained. “For this reason, we chose a site that isn’t directly impacted by primary vehicle emissions.”

The study was conducted during Joel Ferreira de Brito’s postdoctoral research, which Artaxo supervised. The model used to analyze the data was developed by Brazilian economist Alberto Salvo, a professor at the National University of Singapore and first author of the article. Franz Geiger, a chemist at Northwestern University in the US, also collaborated.

“We adapted a sophisticated statistical model originally developed for economic analysis and used here for the first time to analyze the chemistry of atmospheric nanoparticles,” Artaxo said. “The main strength of this tool is that it can work with a large number of variables, such as the presence or absence of rainfall, wind direction, traffic intensity, and levels of ozone, carbon monoxide and other pollutants.”

Analyses were performed before, during and after a sharp fluctuation in ethanol prices leading consumers to switch motor fuels in São Paulo City. While no significant changes were detected in levels of inhalable fine particulate matter (PM2.5 and PM10), the study proved in a real, day-to-day situation that choosing ethanol reduces emissions of ultrafine particles. To date, this phenomenon had only been observed in the laboratory.

“These results reinforce the need for public policies to encourage the use of biofuels, as they clearly show that the public lose in health what they save at the pump when opting for gasoline,” Artaxo said.

In São Paulo, a city with 7 million motor vehicles and the largest urban fleet of flexible-fuel cars, it would be feasible to run all buses on biofuel. “We have the technology for this in Brazil – and at a competitive price,” he said.

The fact that the city’s bus fleet still depends on diesel, Artaxo warned, creates an even worse health hazard in the shape of emissions of black carbon, one of the main components of soot and a pollutant that contributes to global warming. Alongside electricity generation, the transportation sector is the largest emitter of pollutants produced by the burning of fossil fuels.

For Artaxo, incentives for electric, hybrid or biofuel vehicles are vital to reduce greenhouse gas emissions. “By incentivizing biofuels, we could solve several problems at once,” he said. “We could combat climate change, reduce harm to health and foster advances in automotive technology by offering a stimulus for auto makers to develop more economical and efficient cars fueled by ethanol.”

Here’s a link to and a citation for the paper,

Reduced ultrafine particle levels in São Paulo’s atmosphere during shifts from gasoline to ethanol use by Alberto Salvo, Joel Brito, Paulo Artaxo, & Franz M. Geiger. Nature Communications 8, Article number: 77 (2017) doi:10.1038/s41467-017-00041-5 Published online: 18 July 2017

This paper is open access.