Июль 2024 г.

Российская наука и мир (по материалам зарубежной электронной прессы)

CONTENTS / ОГЛАВЛЕНИЕ


• When ultrashort electron bunch accelerates and drastically stops, it can generate terahertz radiation
• Polymeric coating improved piezoelectric properties of composites for drug delivery
• Création de la première carte mondiale des lipides du cerveau humain
• Stunning 3D chromosomes in frozen mammoths may help resurrect the beasts
• The most ancient human genome yet has been sequenced - and it’s a Denisovan’s
• What could explain the gallium anomaly?
• Comparing hunting choices in hamsters using data compression techniques
• Russia unveils timeline for building its new space station, starting in 2027
• New reconstruction shows low Artic sea ice cover in mid-20th century
• Methane "kitchens" in Siberia's permafrost form mounds that can erupt, creating giant craters
• Plants of the Kaliningrad region turned out to be rich in antioxidants and antimicrobials

В Институте общей физики им. А.М.Прохорова РАН использовали эффект Вавилова-Черенкова для генерации терагерцового излучения. Основная идея заключается в подаче сверхкоротких лазерных импульсов на поверхность катода, что приводит к образованию сверхкороткого электронного сгустка. Далее электроны разгоняются с помощью внешнего поля и резко останавливаются в тонком слое диэлектрика, вследствие чего возникают электромагнитные импульсы в терагерцовом и СВЧ-диапазоне.

The propagation of charged particles in a medium at a speed exceeding the phase speed of light in the medium (this speed also called superluminal) leads to the generation of radiation. The diagram of generated radiation during this process has a conical structure. This effect, called the Cherenkov effect, has many fundamental and applied applications, and its explanation was awarded the Nobel Prize in Physics in 1958.
The oblique incidence of light on the interface between two media is a similar phenomenon; in this case, a wave of secondary radiation sources is formed along the interface, which propagates at a speed exceeding the phase speed of light.
The refraction and reflection of light from an interface is the result of the addition of the amplitudes of waves from all sources formed during light incidence. If one considers the interface with photo emissive material - the cathode, on which light is incident obliquely and causes of electron emission - then an electron density wave will form along the cathode surface at superluminal speed.
This phenomenon is accompanied by the generation of secondary radiation. The application of an external electric field leads to the acceleration of electrons and, as a consequence, an increase in the energy of electrons and secondary radiation for such sources.
Researchers from the Prokhorov General Physics Institute of the Russian Academy of Sciences have proposed using the formation of a superluminal wave of electron emission sources to generate terahertz radiation. The study, titled "Pulsed THz radiation under ultrafast optical discharge of vacuum photodiode", has been published in Frontiers of Optoelectronics.
The main idea is to apply ultrashort laser pulses to the surface of the cathode, which leads to the formation of an ultrashort electron bunch. Next, the electrons are accelerated by an external field and abruptly stopped in a thin layer of dielectric, which led to the generation of electromagnetic pulses in the microwave and in the terahertz range.
The authors propose scaling such sources by increasing the efficiency of photo emissive coatings. Results of this work open new sources of THz radiation for tasks of broadband noninvasive tomography, imaging, radar and power effects on electronics.

Ученые Балтийского федерального университета имени Иммануила Канта выяснили, что полимерное покрытие позволяет улучшить свойства магнитоэлектрических композитов, которые используются в медицине для доставки лекарств, а также при создании имплантов и искусственных тканей. Способность композита накапливать электрический заряд при физическом воздействии увеличивается на 40%, а электроимпульсы эффективнее стимулируют деление клеток в составе искусственных тканей.

Scientists from Immanuel Kant Baltic Federal University found out that polymeric coating enables to improve the structure and properties of magnetoelectric composites, that are used in medicine for drug delivery and also in creation of implants and tissues. Thus, modification with polymer helps equal distribution of composite's components, and also enhances its piezoelectric properties by 40%. That means that material accumulates electric charge after physical impact more quickly. Such ability can be used, for instance, for stimulation of growth and evolution of cells in tissues. Results of the research, supported by the grant of President program of Russian Scientific Fund (RNF), are published in Journal of Magnetism and Magnetic Materials.
Composites that have both magnetic and electric properties, are widely used in medicine, for instance, for drug delivery, for creation of tissues and implants. Besides, these compounds are used as catalysts in chemical industry. As an example of such composite, you can take a material on the base of magnetic nanoparticles from cobalt ferrite and polyvinylidene fluoride - fluorine containing polymer that have piezoelectric properties, in other words it is able to accumulate electric charge in response to physical impact. By this electric and magnetic characteristics of a composite are determined not only by properties of its components but their structure and mutual arrangement. However, there is still not enough information if coating of nanoparticles with additional materials, modifying their structure, can influence the structure and properties of composites.
Scientists from Immanuel Kant Baltic Federal University (Kaliningrad) studied, how modification of nanoparticles of cobalt ferrite with polymer polyethyleneglycol influences properties of the composite. To achieve this aim physics held nanoparticles in the solution of polyethyleneglycol during one hour, and then removed excessof polymer. Scientists dissolved modified nanoparticles with powder of polyvinylidene fluoride, poured the obtained solution in molds and dried till films appeared. Authors also analogously obtained composites, in which nanoparticles weren't treated with polymer.
Study of materials' structure shows that unmodified nanoparticles often aggregate, that means, stick together, as a result of it composite becomes discontinuous: in it appear areas with accumulation of particles and spaces without them. Modification with polyethyleneglycol helps equal distribution of nanoparticles in the matrix of polyvinylidene fluoride. Thus, the surface area of composites without particles reduced from 16% to 1 %, and the size of agglomerates from stuck together particles reduced by 39%.
Modified composites saved as magnetic and also piezoelectrical properties, that are characteristic for the base material. Moreover, treatment with polyethyleneglycol enhanced the ability to accumulate electric charge during physical impact of composite by 40% thanks to changes in its microstructure. Thus, modified composite reacted on physical impact more quickly. Elaborated materials potentially can be used in regenerative medicine. Thus, electrical impulses created by them in response to pressure can stimulate cell division in tissues and implants.
"In frames of further research, we plan to study mechanisms of interaction of polymer coating with components of magnetoelectric composites more profoundly. In future these materials can become a key element in creation of intellectual implants and bioelectrical systems, that are able to interact with living cells on the molecular level. Abilities of appliance of elaborated composites will open new horizons in regenerative medicine, and so enable creation of self-renewing artificial tissues. These researches pave the way to medicine of the future, where technology and biology are united for achievement of earlier unknown heights in treatment and recovery of human's health", - tells Vitalii Salnikov, research laboratory assistant, Research and Education Center "Smart Materials and Biomedical Applications" of Immanuel Kant Baltic Federal University.

Исследователи из России, Сингапура и Германии создали первую карту основных, но при этом малоизученных компонентов головного мозга человека - липидов. Ученые идентифицировали в 75 областях мозга 419 липидов, 93% из которых распределены неодинаково между разными частями. Дальнейшее изучение липидного состава поможет выявлять различные заболевания мозга и когнитивные расстройства.

Des scientifiques ont découvert que 93 % des lipides du tissu cérébral sont répartis différemment dans la matière blanche et grise, le sous-cortex, les cortex visuel et moteur et le cortex préfrontal, qui est responsable de la prise de décision, du comportement social et d'autres fonctions. Les anomalies du lipidome cérébral ont tendance à se produire dans les troubles mentaux et cognitifs, donc la cartographie de ces molécules devrait aider à obtenir plus d'informations sur la maladie. La recherche financée par une subvention du programme présidentiel de la Fondation scientifique russe (RSF) a été publiée dans Nature Communications.
Les lipides sont un composant majeur du tissu cérébral. Ce sont des composés gras qui constituent 35 à 40 % de toutes les molécules des corps cellulaires de la matière grise et jusqu'à 78 % des gaines de myéline des axones de la matière blanche. Les lipides du tissu cérébral sont très divers et comprennent le cholestérol, les composés contenant du phosphore, tels que les phospholipides et les sphingolipides, ainsi que d'autres molécules. Étant donné que les lipides sont impliqués dans le métabolisme et la croissance des neurones, la transmission de signaux entre les cellules et le contrôle des processus inflammatoires, des anomalies dans la composition du lipidome ont été associées à des troubles cognitifs, tels que l'autisme, la schizophrénie et la maladie d'Alzheimer. Cependant, la relation entre le lipidome et les caractéristiques structurelles du tissu cérébral reste mal comprise, ce qui limite l'utilisation des lipides comme marqueurs moléculaires pour détecter les maladies cérébrales.
Des chercheurs de l'Institut de science et de technologie de Skolkovo et leurs collègues ont créé la première carte mondiale des lipides cérébraux humains. Ils ont étudié des échantillons de tissu cérébral de quatre individus en bonne santé et ont évalué la composition lipidique de 75 parties différentes du cerveau. Les lipides présents dans les échantillons ont été identifiés à l'aide de la spectrométrie de masse, qui permet de déterminer la structure d'une molécule à partir du rapport masse/charge et de son schéma de mouvement dans un champ magnétique.
Les chercheurs ont identifié un total de 419 lipides différents, la plupart (93 %) inégalement répartis entre les différentes parties du cerveau humain. Par exemple, le sous-cortex (la partie la plus ancienne du cerveau), les cortex moteur et visuel présentaient des niveaux relativement élevés de cholestérol, tandis que le cortex préfrontal, responsable du comportement social complexe et de la prise de décision, présentait des niveaux relativement faibles de ce lipide.
La plupart des lipides se trouvant dans les gaines de myéline, l’équipe a vérifié si la teneur en myéline d’une partie particulière du cerveau affectait son lipidome typique. La matière blanche riche en myéline s’est avérée contenir principalement des céramides, deux classes de phospholipides et des lipides contenant des acides gras saturés. La fonction principale de la matière blanche étant de transmettre des signaux via les axones, ces types de lipides sont considérés comme essentiels pour que le tissu puisse remplir sa fonction.
Les lipides d'acides gras polyinsaturés prédominent dans la matière grise qui contient une concentration de corps cellulaires plutôt que d'axones et pratiquement pas de myéline. Cela suggère que ces molécules peuvent être importantes pour le traitement du signal dans les cellules.
«À l'avenir, nous prévoyons d'étudier en profondeur le lipidome sous-cortical, qui n'a été que partiellement couvert par cette recherche, et d'étudier des échantillons de cerveau de patients atteints de divers troubles mentaux. Le « décodage » complet potentiel du lipidome nous aidera à mieux comprendre la nature de la maladie mentale et son impact sur la structure et le fonctionnement du cerveau », a déclaré Maria Osetrova, ingénieure de recherche au Skoltech Neuro Center et participante au projet soutenu par RSF.
D’autres organisations impliquées dans cette recherche comprenaient l’Université d’État Lomonossov de Moscou, le Centre fédéral de recherche Semenov pour la physique chimique de l’Académie des sciences de Russie (Moscou), l’Université de Leipzig (Allemagne) et l’Université nationale de Singapour.

Международная команда генетиков реконструировала полный геном мамонта возрастом 52 тысячи лет и трехмерную структуру его хромосом с нанометровым разрешением. Такой уровень детализации стал возможен благодаря тому, что после гибели животного его останки оказались не только заморожены, но и полностью обезвожены, в результате чего в тканях образовалось так называемое хроматиновое стекло - перешедшие в стеклообразное состояние петли нуклеопротеида хроматина, составляющего основу хромосом. Это предотвратило распад и диффузию молекул хроматина, сохранившего свою трехмерную структуру.
В работе принимали участие ученые из Дании, Австралии, США, Испании, Швеции, Норвегии и России (Институт молекулярной и клеточной биологии СО РАН, Институт цитологии и генетики СО РАН, Академия наук Республики Саха (Якутия), Институт биологических проблем криолитозоны СО РАН).

The first sign that Erez Lieberman Aiden and his team were onto something special was the ice age beast’s hairdo. Woolly mammoth hides that froze, thawed, and refroze tend to go bald. But the mammoth that had perished some 52,000 years ago in Siberia had retained a tangle of chestnut-brown hair over much of its body, suggesting it had stayed frozen since the animal died.
The closer the scientists peered, the more wonders they beheld. A microscope revealed the mammoth’s hair follicles. Looking even closer, they saw loops of chromatin - the DNA and proteins that make up chromosomes - preserved in a glasslike state in which the molecules are packed tightly.
From that exquisite slab of skin, the researchers assembled the mammoth’s genome and the 3D architecture of its chromosomes. The structure closely resembles that of modern elephants and showed the genome in action, revealing clues to which genes were active in mammoth skin, as Aiden, director of the Center for Genome Architecture at Baylor College of Medicine (BCM), and colleagues report in the 11 July issue of Cell. "This is a fantastic result that has the potential to become a real milestone," says Michael Hofreiter, an evolutionary geneticist at the University of Potsdam who was not involved in the study.
Knowing the structure of the mammoth genome may put wind in the sails of controversial efforts to resurrect the beast. More generally, Hofreiter says, the results could "move research on extinct species forward in ways we long wanted." "The next big forefront in the field will come from novel chemistry to unlock deeper time fossils," older than 1 million years, adds Hendrik Poinar, an evolutionary geneticist at McMaster University who also was not involved in the study.
Chromatin glass, or "chromoglass," as the researchers call it, can form in tissues that have been desiccated like beef jerky, says co-author Marc Martí-Renom, a structural geneticist at the Spanish National Center for Genomic Analysis (CNAG). "We believe dehydration is the key element here," not temperature, he says. Such desiccation may have occurred in other remains in Siberia’s vast permafrost meat locker, and perhaps in nonfrozen remains such as Egyptian mummies.
The hunt for long-lost chromosomes began a decade ago, when Aiden, along with BCM’s Olga Dudchenko and Tom Gilbert of the University of Copenhagen, sought to apply to ancient DNA a technique called Hi-C that Aiden had helped pioneer. Hi-C offers a way to sequence genomes in 3D. In ordinary DNA sequencing, the spatial structure of an organism’s DNA is lost. "Imagine you have a puzzle that has 3 billion pieces, but you don’t have the picture of the final puzzle to work from," Martí-Renom says. Hi-C chemically joins parts of a genome that are naturally in contact, giving "an approximation of that picture before you start putting the puzzle pieces together." Researchers able to see DNA structure at this scale can assemble genomes using Hi-C data alone.
The team set out to modify its Hi-C protocol for ancient samples. But "PaleoHi-C" would only work if the chromatin had retained its 3D structure. The team probed numerous samples of mammoth tissue and museum specimens - to no avail. "It was years and years of failing," says BCM co-author Cynthia Pérez Estrada.
They finally hit pay dirt after co-author Love Dalén, an evolutionary geneticist at the Centre for Palaeogenetics in Stockholm, put them onto the chestnut-haired mammoth that Russian scientists excavated in Siberia in 2018. The team also studied samples from another mammoth, which has been hailed as the best preserved specimen ever: a young female nicknamed Yuka, found near the Laptev Sea in 2010 by local Yukagirs. Together the two mammoths revealed "a new type of fossil," that preserves 3D structure and long strings of DNA, Aiden says: "Fossil chromosomes that span a million-fold more sequence than typical ancient DNA fragments."
The results confirm that mammoths, like modern elephants, had 28 chromosomes. The genomes have "nearly identical" structures, Gilbert says. "Boring for us, but great for the de-extinction people." For example, the biotech firm Colossal Biosciences is planning to splice quintessential mammoth genes into the elephant genome - a task made easier by the kissing-cousin chromosomes - and then use modern elephants as surrogate mothers to give birth to a mammothlike creature.
What’s more, genome architecture "tells you a heck of a lot about function," Aiden says. "We can figure out which genes were active, and which were inactive." That’s because chromosomes are segregated into different neighborhoods for active and inactive genes - compartments still discernible after 52,000 years. Aiden’s team inferred the expression of genes linked to hair follicle development was altered in mammoth skin compared with elephant skin.
Meanwhile, the team sought to better understand the conditions that give rise to chromoglass. Normally, after death, chromatin molecules break apart and diffuse through the cellular matrix, like sugar dissolving in hot coffee. "Our hypothesis is that when tissues like these are cooled and dehydrated, a molecular traffic jam can develop and get so bad that diffusion almost totally stops," Aiden says. (This condition also protects cells from microbes that break down organic material, he says.) Physicists call such a material a "glass." To test the idea, the team took dehydrated beef liver, stored it for a year at room temperature, and confirmed the chromosomes retained their original folding pattern. They playfully confirmed it was durable by running over the homemade jerky with a car, immersing it in acid, striking it with a fastball, and blasting it with a shotgun. "At nanoscale, the chromosome architecture is perfectly intact," Aiden says.
Still, such molecular time capsules have not turned up in other ancient specimens. More samples, from tissues other than skin, may be needed to resurrect a mammothlike beast. "Gene expression in other tissues is a big unknown," says co-author Juan Antonio Rodríguez, also at Copenhagen.
Thus, Hofreiter says, "The foremost question" is whether this study "will remain an anecdotal curiosity that is interesting, but scientifically is a cul-de-sac." Poinar is bullish: He predicts that as the Siberian permafrost thaws, "more remains will pop out and may be amenable to Hi-C." For mammoth buffs, the prospects for hearing that magnificent ice age beast bellow have grown a little brighter.

На ежегодном собрании Общества молекулярной биологии и эволюции (Society for Molecular Biology and Evolution), проходившем 7-11 июля в Пуэрто-Вальярта (Мексика) была представлена расшифровка древнейшего на данный момент генома человека - денисовца, жившего около 200 тысяч лет назад. ДНК удалось выделить в Институте эволюционной антропологии общества Макса Планка из зуба, найденного в Денисовой пещере сотрудниками Института археологии и этнографии СО РАН.

By the time population geneticist Stéphane Peyrégne gave his talk Tuesday afternoon at a meeting in Puerto Vallarta, Mexico, rumors had circulated and the auditorium was packed. He didn’t disappoint: "I’m pleased to tell you about a new Denisovan genome from a 200,000-year-old male," said Peyrégne, a postdoc at the Max Planck Institute for Evolutionary Anthropology.
The genetic sequence he unveiled is the oldest high-quality human genome yet - 80,000 years older than the previous record holder: a Neanderthal that lived about 120,000 years ago. The new results come after more than a decade of effort to find fossilized bones and a second genome of a Denisovan, the mysterious archaic human discovered through its DNA 14 years ago. That first Denisovan genome came from a girl’s pinkie finger bone dated between 60,000 to 80,000 years ago. The genomes of both Denisovans and the ancient Neanderthal all came from the same cold, fossil-rich site: Denisova Cave in the Altai Mountains of Siberia.
According to the analysis by Peyrégne and colleagues, the newly sequenced male comes from a distinct population of early Denisovans that interbred multiple times with a group of Neanderthals whose population had not been detected in DNA before.
"As someone who has been thinking about Denisovans for the past decade, the news of a new Denisovan genome was incredibly thrilling," says population geneticist Emilia Huerta-Sanchez of Brown University, who co-organized the session at the annual meeting of the Society for Molecular Biology and Evolution. "It’s not just another ancient genome," adds population geneticist Priya Moorjani of the University of California, Berkeley, who was also at the talk. "It tells a lot more about these elusive ancestors."
Denisovans are primarily known from their DNA. Researchers have the genome of the girl, as well as bits of nuclear and mitochondrial DNA from fragmentary fossils - teeth, a toe bone - of seven additional individuals, all also from Denisova Cave. Scientists have also identified some Denisovan DNA in living humans, including in Papuans and Han Chinese people, acquired from past interbreeding. DNA in sediments showed that Denisovans were first in the cave 300,000 years ago, and later lived in a cave on the Tibetan Plateau. The scanty fossils reveal this archaic human had larger molars than did the Neanderthals and a robust lower face, known from a jawbone in China. But no one really knows what Denisovans looked like.
Excavations in Denisova Cave have continued, and archaeologist Maxim Kozlikin of the Russian Academy of Sciences (RAS) found a molar in a deep layer dated to 200,000 years ago, Peyrégne reported in his talk. The RAS team sent the molar to Max Planck, where evolutionary geneticists extracted enough DNA to provide 24-fold coverage of the genome, considered exceptional for such old DNA. Working in the lab of computational biologist Janet Kelso, Peyrégne and colleagues compared the new DNA sequence with that of Neanderthals, other Denisovans, and modern people.
The DNA analysis revealed the male Denisovan had inherited 5% of his genome from an ancient, previously unknown population of Neanderthals. The male, labeled Denisova 25, came from a separate population of Denisovans from the girl, known as Denisova 3, and from the other Denisovans in the cave. The girl’s DNA is more closely related to the Denisovan sequences in living modern humans, who got them from at least two Denisovan populations.
All this suggests the older male’s population was replaced in the cave by later Denisovans, Peyrégne said in his talk. The data also suggest the male Denisovan’s ancestors interbred multiple times with Neanderthals. Denisovans were apparently replaced in the cave by Neanderthals for a period, based on the Neanderthal fossil dated to about 120,000 years ago. By about 60,000 years ago, though, the Denisovans had moved back in. The two groups may even have met in the cave - DNA from a bone fragment from a female who was more than 50,000 years old shows her mother was a Neanderthal and her father a Denisovan. Later, both DNA and fossils indicate modern humans occupied the cave and Denisovans and Neanderthals disappear. The region was clearly a crossroads for various types of humans, Peyrégne said in the talk.
Although Denisovans and Neanderthals apparently interbred repeatedly, their lineages are distinct: They diverged from a common ancestor at least 400,000 years ago. The ancestors of Neanderthals settled in Europe and the Middle East, whereas Denisovans headed farther east into Asia where they evolved separately, acquiring roughly 300,000 genetic changes that differentiate them from Neanderthals, according to the new genome. "Neanderthals and Denisovans remain in separate groups," and mixed at the edges of their geographic ranges, Peyrégne said in his talk.
In the question and answer period, an audience member asked whether the male’s genome also had DNA from an even older, unidentified type of human - perhaps Homo erectus - whose DNA has been spotted in the Denisovan girl’s genome. "If there is any Denisova superarchaic ancestry, it’s also present in this genome," Peyrégne responded. "[That DNA] is shared between Denisova 3 and Denisova 25."
The Max Planck researchers plan to publish the new genome soon. "It’s truly exciting to have one more genome from this mysterious group," Moorjani says. "It tells us a lot more about these elusive ancestors … to learn what this group was like and how it interacted with other groups."

В 1989 г. в Баксанской нейтринной обсерватории в Кавказских горах начался советско-американский эксперимент SAGE (Soviet-American Gallium Experiment) для измерения потока солнечных нейтрино с помощью жидкого галлия - при захвате нейтрино галлием-71 получался германий-71. Двадцать с лишним лет эксперимента показали, что фактическая скорость захвата нейтрино и, соответственно, образования атомов германия гораздо ниже теоретически предсказанной. Явление получило название галлиевой аномалии, проявившейся и в ходе сменившего SAGE Баксанского эксперимента по стерильным переходам BEST (Baksan Experiment on Sterile Transitions). Возможных объяснений могло быть много: от ошибок в измерениях до существования нового, четвертого типа трудноуловимых элементарных частиц, названных стерильными нейтрино. В своем недавнем исследовании ученые Ливерморской национальной лаборатории и Национальной лаборатории Лоуренса в Беркли опровергли очередное предположение о неправильном измерении, доказав, что скорость превращения галлия в германий была измерена точно, а значит, гипотеза о новом типе нейтрино может оказаться верной.

Deep in the Caucasus Mountains, on the border between Russia and Georgia, an unusual experiment is taking place. In an underground lab shielded by a mountain of rock, highly radioactive material sits inside a vat of liquid gallium, blasting out particles called neutrinos that break the gallium down into atoms of germanium.
The goal is to resolve a little-known mystery of physics: the gallium anomaly. "I think it’s one of the most compelling anomalies in neutrino physics that we have today," said Ben Jones, a neutrino physicist at the University of Texas, Arlington. Some three decades ago, in a previous version of the current experiment, scientists first detected a dearth of the expected germanium atoms that still can’t be explained.
Since then, physicists have worked to rule out possible mismeasurements or inaccuracies that could explain the anomaly. Now they’ve eliminated another one. Eric Norman, a nuclear physicist at the University of California, Berkeley, and colleagues have announced that one possible solution, an incorrect calculation of the half-life of germanium, can’t be the cause.
"The half-life is correct," Norman said. "This is not the explanation for the gallium anomaly."
That leaves few possibilities. One is that some still-unknown experimental defect caused the anomaly. Perhaps a different mismeasurement is throwing things off, or a misunderstanding of nuclear physics. Or maybe, just maybe, the anomaly points to a monumental discovery, the existence of a new type of elementary particle called a sterile neutrino. Sterile neutrinos were initially proposed to explain why the masses of the three known neutrinos are so tiny, but they could also account for at least some of the invisible "dark matter" that fills the cosmos.
"We cannot find some huge uncertainty in our experimental procedures," said Vladislav Barinov, a particle physicist at the Institute for Nuclear Research of the Russian Academy of Sciences who works on the experiment in the Caucasus. "Is it a new type of neutrino? We don’t know."
Neutrino Village
At the height of the Cold War, before the fall of the Berlin Wall in 1989 and the subsequent dissolution of the Soviet Union, an unlikely partnership arose in the form of an experiment called SAGE, the Soviet-American Gallium Experiment. "The Soviet Union had a phenomenal group of theoretical scientists," said Steven Elliott, a nuclear physicist at Los Alamos National Laboratory who worked on the project. But they lacked money and access to certain technologies that would make SAGE possible, he said. "Los Alamos was able to provide those types of resources."
SAGE was constructed at the Baksan Neutrino Observatory, a neutrino physics facility built in the 1960s and 1970s inside a mountain in Russia’s Baksan Valley, about 3 miles from the Georgian border. The 13,000-foot-tall Mount Andyrchi shielded the facility from cosmic rays and other sources of noise, allowing precise neutrino experiments to take place.
A nearby residential area called Neutrino Village housed the families of the scientists who worked at the facility, as well as visiting international scientists like Elliott. "I did go out for a number of trips," he said. "I found it an adventure."
SAGE began in 1989 and continued for more than 20 years despite attempts by the Russian government to sell its gallium, a precious metal that’s liquid at room temperature. The project was designed to investigate the solar neutrino problem, a measured deficit of neutrinos streaming from the sun. Specifically, scientists were finding a shortage of electron neutrinos, one of three known types, or "flavors." That problem was ultimately resolved in the 2000s with the Nobel Prize-winning discovery that neutrinos oscillate between flavors as they travel. By the time many of the electron neutrinos from the sun reach Earth, they have become something else.
SAGE used a tank of 57 metric tons of gallium. Incoming electron neutrinos would occasionally combine with a neutron inside a gallium atom and convert it into a proton, turning the gallium into germanium. The scientists counted the germanium atoms in a monthlong extraction process. They chose gallium for the experiment because it has a "low threshold for this reaction," Elliott said. A similar experiment began in Italy in 1991, called Gallex.
In the mid-1990s, researchers tweaked both experiments to use neutrinos from radioactive elements. They hoped to avoid unknown errors related to the solar neutrino problem. But both experiments generated roughly 20% less germanium than expected - surprise results that couldn’t have been caused by the solar neutrino problem. "They exactly knew the source activity and how many neutrinos are produced," said Inwook Kim, a nuclear physicist at Los Alamos. Soon, the puzzling discrepancy had a name: the gallium anomaly. "It was really surprising," Barinov said.
A follow-up experiment that began at Baksan in 2014, called the Baksan Experiment on Sterile Transitions (BEST), uses two gallium chambers instead of one, to determine whether the anomaly could be explained by the distance from the source of the neutrinos. "BEST was constructed to resolve this tension," said Barinov, who has worked on the experiment since 2015. But both chambers have continued to show a shortfall relative to what models predict. "It’s a really unusual result," he said.
Half-Life Theory
Repeated results from BEST continue to show the anomaly as recently as 2022. One chamber contained only 79% of the expected amount of germanium, the other only 77%. "Everybody was hoping that anomaly would go away," said Wick Haxton, a theoretical physicist at Berkeley. "There is still not any clean understanding of what’s going on."
A possible explanation was floated: that the half-life of germanium-71 (the specific isotope produced in the experiment), measured in 1985 to be 11.43 days, was actually longer. The same constant controls germanium-71’s decay rate and the rate at which gallium captures neutrinos to produce that germanium. That means a longer germanium-71 half-life would imply a lower rate of neutrino capture and hence germanium production, which could explain the lack of germanium seen by SAGE, Gallex and BEST.
Norman and colleagues published a reinvestigation of this half-life in Physical Review C in late May. Using a nuclear reactor at the McClellan Nuclear Research Center at the University of California, Davis, they irradiated "very pure germanium material," Norman said, producing germanium-71. They then analyzed the samples over 80 days to see how long it took the atoms to decay.
They arrived at a half-life of 11.468 days, extremely close to the 1985 measurement, ruling the half-life out as the explanation for the gallium anomaly. While no one ever quite believed the original half-life measurement to be wildly incorrect, researchers still considered it worth checking. "It was a measurement that needed to be done," Jones said.
Another proposed explanation was that physicists had miscalculated the probability of neutrinos from the source interacting with the gallium. But in September 2023, Haxton and his colleagues also ruled out this possibility. "You can’t get rid of the anomaly," he said.
That leaves physicists in an uncomfortable position. Either there is still some error that no one has thought of, or, as Haxton put it, "something unusual is going on with neutrinos." For instance, the experiments might point to a controversial additional type of neutrino, undetected by most other experiments, that might also help to explain dark matter.
Sterile Neutrinos
The three known flavors of neutrinos, which are all millions of times lighter than electrons, interact with other elementary particles via the weak force, which makes them detectable. Sterile neutrinos, on the other hand, would interact only via gravity. If they’re much heavier than the known neutrinos, their existence could explain why the known neutrinos are so light, through an inverse relationship hypothesized around 1980 called the seesaw mechanism.
The gallium anomaly, however, would point toward a lighter-weight sterile neutrino, with the electron neutrinos emitted by the radioactive source sometimes oscillating into a sterile neutrino that wouldn’t interact with the gallium.
In some models, lightweight sterile neutrinos could comprise a fraction of the universe’s dark matter, though not all of it because they would be too light to gravitationally shape the universe in the way dark matter does. "They could be a small subset of it," said Lindley Winslow, an experimental nuclear and particle physicist at the Massachusetts Institute of Technology.
Other attempts to find sterile neutrinos by studying neutrino oscillation patterns, however, have been largely unsuccessful. The number of researchers who support the light sterile neutrino "is sort of shrinking," Winslow said. Kevork Abazajian, an astrophysicist at the University of California, Irvine, said they are the "underdogs of the particle physics community."
If they do exist, light sterile neutrinos will "wreak havoc" on our current understanding of cosmology, Abazajian said, including ideas of how atoms formed in the minutes following the Big Bang and the theory of the cosmic microwave background, the remnant heat from the initial expansion of the universe. "You would expect to see the presence of this extra neutrino," Abazajian said. However, he added that recent work has shown that alternative models of the sequence of events in those first minutes "can accommodate light sterile neutrinos."
In lieu of other explanations for the gallium anomaly, light sterile neutrinos remain a possibility that we just can’t eradicate. "I’ve been a bit skeptical of the sterile neutrino hypothesis, but I can’t tell you why it’s not right," Elliott said. "There’s never been a convincing explanation of why the experiment might be wrong."
While Russia’s invasion of Ukraine "has complicated things," Elliott said, the collaboration between the U.S. and Russia on BEST is still ongoing, for now. Barinov says the team at Baksan is considering using a new source of neutrinos, such as zinc, to further test the result. They may even construct a third chamber of gallium around the source. For now, the anomaly remains unsolved, with no sign of a resolution on the horizon. "It has us all puzzled," Haxton said.

Зоологи из Института систематики и экологии животных СО РАН и Института проблем экологии и эволюции им. А.Н.Северцова РАН проанализировали охотничье поведение пяти видов хомяков и пришли к выводу, что влияние на его формирование в семействе Cricetidae в первую очередь оказывают не филогенетические различия, а экологические факторы. Самое изменчивое и непредсказуемое поведение на охоте продемонстрировал ранее не изученный мохноногий хомячок Роборовского, один из самых маленьких видов.

Research into the hunting behavior of Cricetidae family members provides new insights into the evolutionary shifts from omnivorous to predatory lifestyles in rodents.
A recent study conducted by the Russian Academy of Sciences sought to determine whether phylogenetic differences or ecological factors primarily shape the hunting behaviors of hamsters. By analyzing the hunting patterns of five Cricetidae species, including the previously unstudied desert hamster Phodopus roborovskii, the researchers aimed to understand the variability and predictability of these behaviors.
The study employed a data compression approach to compare hunting patterns, treating them as biological "texts." This method allowed for a detailed analysis of the sequences and variability in hunting behaviors across different species. The findings revealed that the hunting behavior of P. roborovskii was the most variable, displaying a range of optional behaviors. In contrast, P. campbelli and Allocricetulus curtatus exhibited more ordered and predictable hunting sequences.
Interestingly, the optional hunting behavior of the ancient species P. roborovskii showed similarities with the obligate hunting patterns of the younger Allocricetulus species. This suggests that P. roborovskii is the most advanced hunter among the Phodopus genus. The study concluded that ecological conditions, rather than phylogenetic differences, play a crucial role in shaping the hunting behaviors of these species.
These findings align with previous research on the evolution of predatory behavior in rodents. For instance, a study on grasshopper mice (Onychomys spp.) demonstrated that these predators have evolved physiological resistance to the toxins of their prey, the bark scorpions (Centruroides spp.). This adaptation allows grasshopper mice to prey on scorpions without suffering the usual effects of envenomation. Additionally, another study found that grasshopper mice have developed a unique mechanism to block pain signals induced by scorpion venom, further facilitating their predatory lifestyle.
The current study expands on these findings by exploring the genetic and behavioral adaptations in Cricetinae species. Similar to the grasshopper mice, the hamsters' hunting behaviors appear to be influenced more by ecological factors than by phylogenetic history. This is consistent with the idea that ecological pressures can drive the evolution of complex traits like predatory behavior.
The methods used in this study, including the data compression approach, allowed for a nuanced analysis of behavioral sequences. By treating hunting patterns as biological texts, the researchers could identify subtle differences and similarities across species. This approach provides a new way to study the evolution of complex behaviors in other animal groups as well.
In summary, the study conducted by the Russian Academy of Sciences highlights the importance of ecological conditions in shaping the hunting behaviors of Cricetinae species. By comparing the hunting patterns of different species, the researchers were able to demonstrate that these behaviors are subject to selection during species divergence. This research not only adds to our understanding of predatory behavior in rodents but also provides a framework for studying the evolution of complex traits in other animals.

Роскосмос обнародовал дорожную карту проекта по постройке собственной космической станции, первый модуль которой планируется вывести на орбиту в 2027 г.

Russia has unveiled a comprehensive roadmap for building its newest space station and associated Earth-based infrastructure, with the first modules expected to launch within three years.
On July 2, the leadership of Russia's space agency Roscosmos described their upcoming mission to create the nation's newest space station, currently known as the Russian Orbital Service Station (ROSS), according to Russian news agency TASS.
The first module of the X-shaped outpost, a research and power node, is expected to be launched into a near-polar orbit in 2027, TASS reported. By 2030, it plans to have docked its four major modules, with two "special-purpose" modules scheduled for attachment by 2033. Roscosmos plans to send the first cosmonauts to the station in 2028 and has suggested the station can be operated without crew.
The Russian Orbital Service Station would orbit at the same altitude as the International Space Station, around 250 miles (400 km) above Earth, in a polar, sun-synchronous orbit. The route is particularly useful for observing the entire surface of the planet, according to Roscosmos, and also provides a valuable view over "the strategically important Northern Sea Route." The estimated cost is about $7 billion USD.
The schedule for building ROSS also depends on the success of the next-generation heavy-lift Angara A5 rocket, which has had three successful orbital flight tests since 2014, and a partial failure in 2021.
Its construction is also likely to contain a first: Russia is riding the AI hype rocket, it seems.
"Artificial intelligence is quickly developing technology." said Vladimir Kozhevnikov, chief designer of ROS, on July 2, according to a report by TASS. "We will use its support but basically we will use our brains, of course," What form this AI takes is unknown - will ChatGPT get a building credit on ROSS modules?
Another chief designer, Vladimir Solovyov of space rocket company Energia, has suggested there will be "unusual" goals for ROSS, with the space station providing guidance for a fleet of satellites - a first.
"This fleet will fly near the station […] this, too, will imply brand-new tasks for mission control as no one has ever endeavored to do so," Solovyov said.
Russia has been a principal member of the International Space Station since launch, alongside NASA, the European Space Agency, JAXA and the Canadian Space Agency. For its new station, it's looking at partnerships with Brazil, India, China and South Africa, in addition to other African countries.
Back in 2021, Roscosmos signaled its intention to build its own space lab, a successor to its Mir space station. In mid-2022, after the invasion of Ukraine and heightened tensions between Russia and other Western countries, Roscosmos announced it would leave the ISS program 'after 2024.' It has since announced it will remain on the ISS until 2028.
Though the timeline for departing the ISS remains uncertain, the schedule signals the Russian space agency's intent to advance its own interests and focus on security and scientific development Roscosmos believes has been hindered due to international agreements on the ISS.
The ISS is expected to undergo a planned deorbit in 2030, but may remain in operation until commercial stations have been built.

Российские, норвежские и китайские климатологи реконструировали сезонную динамику изменения площади морского льда в Арктике с 1901 по 2019 гг. и обнаружили крупную отрицательную аномалию в 1920-х - 1940-х гг., когда летнее сокращение площади льда доходило до 25%. Хотя этот период известен сильным потеплением в Арктике, причины которого до сих пор не установлены, реальные масштабы таяния льдов не были изучены.

An international research team presented a new reconstruction of past Arctic sea ice that revealed low levels of sea ice coverage in the 1940s.
Their results were published on July 26 in a special issue of Advances in Atmospheric Sciences commemorating the life work of Professor Yongqi Gao who passed away in July 2021. The new reconstruction can help climate scientists adjust expectations of future sea ice coverage.
"Understanding the range of sea ice multi-decadal variations in the past, when the anthropogenic forcing was several times weaker than in the present day, is key for assessing mechanisms of climate variations and predicting future changes of the Arctic sea ice," said study co-author Vladimir Semenov from the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences.
The shrinking Arctic sea ice area in recent decades is a striking manifestation of ongoing climate change. This rapid transformation of the cryosphere has important consequences for Arctic ecosystems, society and economy, with impacts that extend to the mean surface temperature of the entire globe.
Since the late 1970s, satellites have been continuously observing seasonal variations of Arctic sea ice over decades. Sea ice variations have been relatively well monitored since the 1950s, but due to a lack of observations, there are no reliable estimates of the Arctic sea ice area in the middle of the 20th century. This period was characterized by a strong warming, known as the Early 20th Century Warming.
Previous studies established the link between surface air temperature and sea ice, which implies that the early 20th Century warming interval was accompanied by a concurrent reduction of Arctic sea ice, but the magnitude and extent of the decline were unclear.
The research team set out to understand the mystery surrounding sea ice anomalies during the 1940s, a period that instrumental observations indicate was almost as warm as today, according to study co-author Noel Keenlyside.
"Surprisingly, previous reconstructions of sea ice do not indicate a large reduction of sea ice," said Keenlyside from the Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research.
The team reconstructed the sea ice patterns in the period with poor data, before 1953, using established co-variability patterns between sea ice, sea surface temperature, and sea level pressure patterns. Constructing distinct regression models for three geographically separated regions - the Arctic Ocean, Bering Sea and the Sea of Okhotsk - improved the fit of the models and reduced uncertainty.
"Our reconstruction using independent data provides the first strong evidence for a large decline of sea ice in the 1940s," Keenlyside said. "This is exciting, because unlike the present warming, emitted anthropogenic greenhouse gases were relatively low."
The reconstruction, called the Institute of Atmospheric Physics sea ICE reconstruction version 1, provides a new baseline for assessing internal climate variability. According to the study, the ongoing sea ice area decline is already significantly beyond the level of internal climate variability - even assuming that the Early 20th Century Warming of the Arctic was primarily caused by internal climate variability. This indicates the importance of anthropogenic forcing.
"Our data can be used as boundary conditions for atmospheric models and reanalyses," Semenov said. "Performing atmospheric model simulations for the 20th century using our sea ice reconstruction may help to identify mechanisms of the Early 20th Century Warming anomaly."
Other contributors of the research include Tatiana A. Aldonina from the Institute of Geography Russian, Academy of Sciences, Fei Li from the Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research and Lin Wang from the Institute of Atmospheric Physics, Chinese Academy of Sciences.

Сибирские ученые описали два механизма формирования загадочных бугров, возникающих в зоне вечной мерзлоты и периодически взрывающихся. В результате подобного взрыва возник, например, известный Ямальский кратер.

Mysterious "frost mounds" dotted across Siberia sometimes burst to form giant craters - and now, scientists have taken a step closer to discovering what makes these strange humps pop.
Frost mounds are areas of the permafrost that bulge as fluids accumulate beneath the surface. According to ongoing research at the Siberian Branch of the Russian Academy of Sciences (SBRAS), two distinct "systems" can lead to this bulging: open and closed. In an open system, water and gas pooling beneath the permafrost move around and leak to the surface through cracks. But in a closed system, water and gas are trapped in a pocket that inflates, putting increasing pressure on the permafrost.
The open system is similar to an idea researchers put forward earlier this year. In a preprint review published Jan. 12 to the EarthArXiv database, the scientists argued that natural gas moving between the bedrock and overlying permafrost leads to melting from below. This melting creates pockets in the permafrost where fluids can accumulate, but these are not completely sealed off from the gas beneath or from the surface. The pockets grow as more gas flows into them, leading to more melting and a rise in pressure, which causes the ground to swell.
The gas is mostly thermogenic methane, which likely forms continuously as a by-product when organic matter heats up. "We call it a kitchen [down there], because it's kind of like cooking, and it's creating gas," Helge Hellevang, a professor of environmental geosciences at the University of Oslo in Norway and lead author of the preprint review, told Live Science.
In a closed system, gas and water come from deep within the bedrock. The fluids rise and form a pocket inside the permafrost that is "surrounded by frozen rocks on all sides," according to SBRAS researchers, and therefore does not leak out.
Despite the distinction between open and closed systems, there is nothing to stop one from morphing into the other as the permafrost evolves, Hellevang said. An open system may even need to become closed before it can form a crater, he said.
Scientists still aren't sure exactly how gas accumulates to form frost mounds, but they know the mounds can rupture spontaneously and open up huge holes in the permafrost. The Yamal crater, measuring about 65 feet (20 meters) wide and 165 feet (50 m) deep, is one example. A helicopter pilot spotted the crater 26 miles (42 kilometers) from the Bovanenkovo gas field on Russia's northern Yamal Peninsula in 2014. Since then, scientists have documented seven more of these giant craters across the Yamal and neighboring Gydan peninsulas.
Researchers with SBRAS said frost mounds "explode" to form the craters, but Hellevang disagrees. Explosions require a source of ignition, such as high heat or electricity, but "it's very hard to ignite the gas at sub-zero," he said. "It's more like an eruption than an explosion."
It's possible open systems could create the pressure necessary for an eruption, but that would require very low gas flow rates out of the system, Hellevang said. Closed systems are more likely to trigger eruptions, as they have a bigger buildup of pressure right away, he said.
Both systems may have a heightened risk of eruption as temperatures rise and thaw the permafrost, Hellevang said. "Climate change is weakening the surface through thawing from the top," he said. At some point, the permafrost becomes so thin it cannot withstand the pressure from pockets of gas below, which could spark eruptions.
Sudden gas eruptions pose a risk to people that live on the Yamal and Gydan peninsulas and to infrastructure like gas pipelines. Another big concern, Hellevang said, is that "if the permafrost is a lid for all this massive amount of methane … then these craters might also in the future be pathways for more methane leakages." And that could trigger even more warming, he said.

Ученые Балтийского федерального университета имени Иммануила Канта, Калининградского государственного технического университета и Кемеровского государственного университета изучили антиоксидантные и противомикробные свойства лекарственных растений, произрастающих в Калининградской области: конского каштана, донника лекарственного, синеголовника приморского и копеечника забытого.

Scientists from the Immanuel Kant Baltic Federal University stated that the biological activity of extracts of four plants that growing in the Kaliningrad region is provided by phenolic compounds - aromatic alcohols. These substances provide antioxidant and antimicrobic properties to Aesculus hippocastanum, Melilotus officinalis, Eryngium maritimum, and Hedysarum neglectum. The extracts of these plants can potentially be used as anti-inflammatory drugs in medicine for the treatment of heart diseases and pulmonology. The results of the research, supported by the Grant of the President program of the Russian Science Fundation (RSF), are published in the journal Food and Raw Materials.
During inflammatory processes, cells accumulate dangerous radicals and oxygen derivatives that can destroy membranes and DNA. Antioxidants can prevent these destructions. Such compounds are naturally found in medicinal plants. In addition, plants can produce substances with antimicrobial activity. Unlike antibiotics synthesized by humans, they don't require expensive research. Official medicine recognizes the potential and gives preference to medicinal plants when it concerns the treatment of many diseases. However, despite the existence of obvious biological activity that is potentially attractive for medicine, some of the medicinal species remains underexplored.
Scientists from the Immanuel Kant Baltic Federal University (Kaliningrad), Kaliningrad State Technical University (Kaliningrad) and Kemerovo State University (Kemerovo) studied the antioxidant and antimicrobial properties of medicinal plants growing in the Kaliningrad region. The researchers chose sea holly (Eryngium maritimum L.), sweet yellow clover (Melilotus officinalis Pall.), sweetvetch (Hedysarum neglectum Ledeb.), and horse-chestnut (Aesculus hippocastanum L.), the biologically active substances of which haven’t been determined yet. Scientists isolated extracts from stems, leaves and flowers and then tested the antioxidant activity of the samples. To do this, the biologists mixed the extracts with a solution of the radical DPPH, which was dark purple but lost its color when a solution of antioxidants was added. Thanks to this color reaction, the scientists were able to estimate whether the extracts contained molecules that prevented the accumulation of radicals.
Scientists also identified a chemical composition of compounds that characterize the antioxidant activity of the extracts. They did this using infrared (IR) spectroscopy, a method based on passing IR radiation through a sample and observing how a substance interacts with the light.
It turned out that the extracts contained a large number of phenols, which are substances containing alcohol with 6 carbon atoms in the form of a ring. The highest number of phenols was found in the leaves, which also showed the highest antioxidant activity against the DPPH radical.
The scientists also tested the antimicrobial activity of the extracts. To do this, they grew cultures of bacteria and microfungi such as E. coli and Candida albicans, which are normally harmless to humans but can cause infections in people with weakened immune systems. They placed extracts on a Petri dish with microorganisms. When plant extracts had antimicrobial substances, bacteria and fungi stopped growing around the place where the extracts were applied. The antimicrobial activity of the extracts was estimated according to the space free of microorganisms. It turned out that sea holly had the strongest antibacterial properties. It effectively suppresses the growth of the hay bacillus (Bacillus subtilis) found in soil, water, air, and human intestines. However, the antimicrobial activity of sea holly was twice lower than that of the industrially produced antibiotic kanamycin. However, although the antimicrobial activity of the plants studied was lower than that of industrial antibiotics, they can potentially be used in the treatment of inflammatory diseases.
"IR spectroscopy can be of great practical importance as a method of express analysis of infusions of medicinal plants. This method can be used in medicine and cosmetology to create safe and effective plant-based products. Thus, based on the results of IR spectroscopy, the studied plants from the Kaliningrad region can potentially be used in medicine for the treatment of heart diseases and pulmonology", - says the head of the project supported by the grant of RSF, Olga Babich, Doctor of Engineering, Director of the Research and Education Center "Applied Biotechnologies", leading research fellow of the Immanuel Kant Baltic Federal University.

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