108 research outputs found
Imaging Molecules from Within: Ultra-fast, {\AA}ngstr\"om Scale Structure Determination of Molecules via Photoelectron Holography using Free Electron Lasers
A new scheme based on (i) upcoming brilliant X-ray Free Electron Laser (FEL)
sources, (ii) novel energy and angular dispersive, large-area electron imagers
and (iii) the well-known photoelectron holography is elaborated that provides
time-dependent three-dimensional structure determination of small to medium
sized molecules with {\AA}ngstr\"om spatial and femtosecond time resolution.
Inducing molecular dynamics, wave-packet motion, dissociation, passage through
conical intersections or isomerization by a pump pulse this motion is
visualized by the X-ray FEL probe pulse launching keV photoelectrons within few
femtoseconds from specific and well-defined sites, deep core levels of
individual atoms, inside the molecule. On their way out the photoelectrons are
diffracted generating a hologram on the detector that encodes the molecular
structure at the instant of photoionization, thus providing 'femtosecond
snapshot images of the molecule from within'. Detailed calculations in various
approximations of increasing sophistication are presented and three-dimensional
retrieval of the spatial structure of the molecule with {\AA}ngstr\"om spatial
resolution is demonstrated. Due to the large photo-absorption cross sections
the method extends X-ray diffraction based, time-dependent structure
investigations envisioned at FELs to new classes of samples that are not
accessible by any other method. Among them are dilute samples in the gas phase
such as aligned, oriented or conformer selected molecules, ultra-cold ensembles
and/or molecular or cluster objects containing mainly light atoms that do not
scatter X-rays efficiently.Comment: 18 pages, 11 figure
Visualization of Geometric Images in Robotics Clubs
Исследование основано на оценке эффективности компьютерной визуализации с точки зрения развития способностей и возможностей школьников. Оно позволяет с применением практических примеров улучшить восприятие и изучение учениками геометрических изображений, а так же их строение.The research is based on assessing the effectiveness of computer visualization in terms of the development of the abilities and capabilities of schoolchildren. It allows, using practical examples, to improve the perception and study of geometric images by students, as well as their structure
Observation of Resonant Diffusive Radiation in Random Multilayered Systems
Diffusive Radiation is a new type of radiation predicted to occur in randomly
inhomogeneous media due to the multiple scattering of pseudophotons. This
theoretical effect is now observed experimentally. The radiation is generated
by the passage of electrons of energy 200KeV-2.2MeV through a random stack of
films in the visible light region. The radiation intensity increases resonantly
provided the Cherenkov condition is satisfied for the average dielectric
constant of the medium. The observed angular dependence and electron resonance
energy are in agreement with the theoretical predictions. These observations
open a road to application of diffusive radiation in particle detection,
astrophysics, soft X-ray generation and etc.. `Comment: 4pages, 4figure
Cystic Form of Duodenal Dystrophy (Clinical Case)
Aim: the reason for the publication was the rare occurrence, as well as the non-specificity of symptoms of the cystic form of duodenal dystrophy. The listed features of this disease lead to difficulties in its differential diagnosis and the choice of the optimal method of treatment.General statements. The report is devoted to the description of a case of successful treatment of a cystic form of duodenal dystrophy — a chronic inflammation of the pancreatic tissue, ectopic in the wall of the duodenum. A 47-year-old patient was admitted to the clinic with complaints of persistent abdominal pain, periodic vomiting, general weakness, weight loss of 20 kg in three months. With the help of computed tomography, the diagnosis was established, the tumor process was rejected, and chronic pancreatitis was detected in the orthotopic pancreas. Due to the presence of changes in the main pancreas, the patient underwent pancreatoduodenal resection. The features of the operation were pronounced infiltrative changes and pronounced vitreous tissue edema, which made it difficult to mobilize the hepatic flexure of the colon and duodenum.Conclusion. Pancreatoduodenal resection is the optimal surgical intervention for the combination of cystic form of duodenal dystrophy with sub-/decompensated duodenal stenosis
First Observation of Self-Amplified Spontaneous Emission in a Free-Electron Laser at 109 nm Wavelength
We present the first observation of Self-Amplified Spontaneous Emission
(SASE) in a free-electron laser (FEL) in the Vacuum Ultraviolet regime at 109
nm wavelength (11 eV). The observed free-electron laser gain (approx. 3000) and
the radiation characteristics, such as dependency on bunch charge, angular
distribution, spectral width and intensity fluctuations all corroborate the
existing models for SASE FELs.Comment: 6 pages including 6 figures; e-mail: [email protected]
Modern venomics – Current insights, novel methods and future perspectives in biological and applied animal venom research
Venoms have evolved >100 times in all major animal groups, and their components, known as toxins, have been fine-tuned over millions of years into highly effective biochemical weapons. There are many outstanding questions on the evolution of toxin arsenals, such as how venom genes originate, how venom contributes to the fitness of venomous species, and which modifications at the genomic, transcriptomic, and protein level drive their evolution. These questions have received particularly little attention outside of snakes, cone snails, spiders, and scorpions. Venom compounds have further become a source of inspiration for translational research using their diverse bioactivities for various applications. We highlight here recent advances and new strategies in modern venomics and discuss how recent technological innovations and multi-omic methods dramatically improve research on venomous animals. The study of genomes and their modifications through CRISPR and knockdown technologies will increase our understanding of how toxins evolve and which functions they have in the different ontogenetic stages during the development of venomous animals. Mass spectrometry imaging combined with spatial transcriptomics, in situ hybridization techniques, and modern computer tomography gives us further insights into the spatial distribution of toxins in the venom system and the function of the venom apparatus. All these evolutionary and biological insights contribute to more efficiently identify venom compounds, which can then be synthesized or produced in adapted expression systems to test their bioactivity. Finally, we critically discuss recent agrochemical, pharmaceutical, therapeutic, and diagnostic (so-called translational) aspects of venoms from which humans benefit
Creating Videos as a Means of Developing the Creative Abilities of Students
В общеобразовательной школе, особенно в начальной и основной школе, в прошлом использовались различные виды дидактических материалов, чтобы наилучшим образом использовать преподаваемый материал, что позволяло учащимся глубже понять преподаваемый материал. Использование таких методов в учебном процессе еще больше расширяется за счет использования современных технических средств, особенно аудиовизуальных технических средств, что обусловлено использованием широкоэкранных телевизоров и проекторов. «Золотое правило» дидактики - обеспечить доступность зрелищных учебных видеороликов, способствовать развитию умственных способностей учащихся, особенно в процессе технологического обучения.In the general education school, especially in primary and secondary schools, various kinds of didactic materials have been used in the past in order to make the best use of the taught material, which allows students to understand the taught material more deeply. The use of such methods in the educational process is further expanding through the use of modern technical means, especially audiovisual technical means, which is due to the use of wide-screen TVs and projectors. The "golden rule" of didactics is to ensure the availability of spectacular educational videos, to promote the development of the mental abilities of students, especially in the process of technological learning
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