46 research outputs found
Mixotrophy of few strains of cyanobacteria and algae isolated from lampenflora communities
In the current study abilities for the mixotrophic growth of phototropic cave strains were observed. The influence of organic substrates on the growth rate on Chlorella vulgaris, Stichococcus bacillaris, Leptolyngbya foveolara, Scytonema were studied. In most cases glucose, maltose, glycerine, malate, acetate, sucrose, and peptone showed a stimulating effect on the culture growth rate by the dark and by the light incubation. Specific abilities for mixotrophic carbon consumption were proved
Beyond Charge Transfer: The impact of auger recombination and FRET on PL quenching in an rGO-QDs system
PL intensity quenching and the PL lifetime reduction of fluorophores located close to gra‐ phene derivatives are generally explained by charge and energy transfer processes. Analyzing the PL from PbS QDs in rGO/QD systems, we observed a substantial reduction in average PL lifetimes with an increase in rGO content that cannot be interpreted solely by these two processes. To explain the PL lifetime dependence on the rGO/QD component ratio, we propose a model based on the Auger recombination of excitations involving excess holes left in the QDs after the charge transfer process. To validate the model, we conducted additional experiments involving the external engi‐ neering of free charge carriers, which confirmed the role of excess holes as the main QD PL quench‐ ing source. A mathematical simulation of the model demonstrated that the energy transfer between neighboring QDs must also be considered to explain the experimental data carefully. Together, Au‐ ger recombination and energy transfer simulation offers us an excellent fit for the average PL life‐ time dependence on the component ratio of the rGO/QD system
Aurintricarboxylic Acid is a Canonical Disruptor of the TAZ-TEAD Transcriptional Complex
Disrupting the formation of the oncogenic YAP/TAZ-TEAD transcriptional complex holds substantial therapeutic potential. However, the three protein interaction interfaces of this complex cannot be easily disrupted using small molecules. Here, we report that the pharmacologically active small molecule aurintricarboxylic acid (ATA) acts as a disruptor of the TAZ-TEAD complex. ATA was identified in a high-throughput screen using a TAZ-TEAD AlphaLISA assay that was tailored to identify disruptors of this transcriptional complex. We further used fluorescence polarization assays both to confirm disruption of the TAZ-TEAD complex and to demonstrate that ATA binds to interface 3. We have previously shown that cell-based models that express the oncogenic TAZ-CAMTA1 (TC) fusion protein display enhanced TEAD transcriptional activity because TC functions as an activated form of TAZ. Utilizing cell-based studies and our TC model system, we performed TC/TEAD reporter, RNA-Seq, and qPCR assays and found that ATA inhibits TC/TEAD transcriptional activity. Further, disruption of TC/TEAD and TAZ/TEAD interaction by ATA abrogated anchorage-independent growth, the phenotype most closely linked to dysregulated TAZ/TEAD activity. Therefore, this study demonstrates that ATA is a novel small molecule that has the ability to disrupt the undruggable TAZ-TEAD interface
Eurasian-Scale Experimental Satellite-based Quantum Key Distribution with Detector Efficiency Mismatch Analysis
The Micius satellite is the pioneering initiative to demonstrate quantum
teleportation, entanglement distribution, quantum key distribution (QKD), and
quantum-secured communications experiments at the global scale. In this work,
we report on the results of the 600-mm-aperture ground station design which has
enabled the establishment of a quantum-secured link between the Zvenigorod and
Nanshan ground stations using the Micius satellite. As a result of a quantum
communications session, an overall sifted key of 2.5 Mbits and a total final
key length of 310 kbits have been obtained. We present an extension of the
security analysis of the realization of satellite-based QKD decoy-state
protocol by taking into account the effect of the detection-efficiency mismatch
for four detectors. We also simulate the QKD protocol for the satellite passage
and by that validate our semi-empirical model for a realistic receiver, which
is in good agreement with the experimental data. Our results pave the way to
the considerations of realistic imperfection of the QKD systems, which are
important in the context of their practical security.Comment: 8+2 pages, 5+2 figure
Value Orientation “Patriotism”: Essence, Content, and Assessment
Background. In the modern historical period, taking into account the current military-political situation, the actualization of the idea of patriotism as a comprehensive element of spiritual integrity of people is a condition for the preservation of Russia as an independent and unified state. The analysis of Russian and foreign scientific literature as well as of regulatory legal documents has shown the absence of a unified approach to the essence and content of the value orientation “patriotism”. There was also no tool for assessing the level of value orientation “patriotism” found.
Objective. The article focuses on the development of a theoretical model of the value orientation “patriotism” and a methodology for assessing the level of its formation.
Sample. 1600 citizens of the Russian Federation took part in the empirical study.
Methods. The study was conducted with an expert survey, focus groups and a sociological survey.
Results. The ANOVA by Kraskel — Wallis showed the validity of the developed methodology for assessing the value orientation of “patriotism” and the absence of statistically significant differences when using it on different sample populations.
Conclusion. The article reveals the essence and content of the value orientation “patriotism”, develops and substantiates its theoretical model, which includes 8 components, as well as means of formation and levels of manifestation. In addition, the study developed and successfully tested a methodology for assessing the level of development of the value orientation “patriotism”
Magnetic Dirac semimetal state of (Mn,Ge)BiTe
For quantum electronics, the possibility to finely tune the properties of
magnetic topological insulators (TIs) is a key issue. We studied solid
solutions between two isostructural Z TIs, magnetic MnBiTe and
nonmagnetic GeBiTe, with Z invariants of 1;000 and 1;001,
respectively. For high-quality, large mixed crystals of
GeMnBiTe, we observed linear x-dependent magnetic
properties, composition-independent pairwise exchange interactions along with
an easy magnetization axis. The bulk band gap gradually decreases to zero for
from 0 to 0.4, before reopening for , evidencing topological phase
transitions (TPTs) between topologically nontrivial phases and the semimetal
state. The TPTs are driven purely by the variation of orbital contributions. By
tracing the x-dependent contribution to the states near the fundamental
gap, the effective spin-orbit coupling variation is extracted. As varies,
the maximum of this contribution switches from the valence to the conduction
band, thereby driving two TPTs. The gapless state observed at closely
resembles a Dirac semimetal above the Neel temperature and shows a magnetic gap
below, which is clearly visible in raw photoemission data. The observed
behavior of the GeMnBiTe system thereby demonstrates an
ability to precisely control topological and magnetic properties of TIs
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High-Quality Graphene Using Boudouard Reaction
Following the game-changing high-pressure CO (HiPco) process that established the first facile route toward large-scale production of single-walled carbon nanotubes, CO synthesis of cm-sized graphene crystals of ultra-high purity grown during tens of minutes is proposed. The Boudouard reaction serves for the first time to produce individual monolayer structures on the surface of a metal catalyst, thereby providing a chemical vapor deposition technique free from molecular and atomic hydrogen as well as vacuum conditions. This approach facilitates inhibition of the graphene nucleation from the CO/CO2 mixture and maintains a high growth rate of graphene seeds reaching large-scale monocrystals. Unique features of the Boudouard reaction coupled with CO-driven catalyst engineering ensure not only suppression of the second layer growth but also provide a simple and reliable technique for surface cleaning. Aside from being a novel carbon source, carbon monoxide ensures peculiar modification of catalyst and in general opens avenues for breakthrough graphene-catalyst composite production
The neutron and its role in cosmology and particle physics
Experiments with cold and ultracold neutrons have reached a level of
precision such that problems far beyond the scale of the present Standard Model
of particle physics become accessible to experimental investigation. Due to the
close links between particle physics and cosmology, these studies also permit a
deep look into the very first instances of our universe. First addressed in
this article, both in theory and experiment, is the problem of baryogenesis ...
The question how baryogenesis could have happened is open to experimental
tests, and it turns out that this problem can be curbed by the very stringent
limits on an electric dipole moment of the neutron, a quantity that also has
deep implications for particle physics. Then we discuss the recent spectacular
observation of neutron quantization in the earth's gravitational field and of
resonance transitions between such gravitational energy states. These
measurements, together with new evaluations of neutron scattering data, set new
constraints on deviations from Newton's gravitational law at the picometer
scale. Such deviations are predicted in modern theories with extra-dimensions
that propose unification of the Planck scale with the scale of the Standard
Model ... Another main topic is the weak-interaction parameters in various
fields of physics and astrophysics that must all be derived from measured
neutron decay data. Up to now, about 10 different neutron decay observables
have been measured, much more than needed in the electroweak Standard Model.
This allows various precise tests for new physics beyond the Standard Model,
competing with or surpassing similar tests at high-energy. The review ends with
a discussion of neutron and nuclear data required in the synthesis of the
elements during the "first three minutes" and later on in stellar
nucleosynthesis.Comment: 91 pages, 30 figures, accepted by Reviews of Modern Physic
CATMoS: Collaborative Acute Toxicity Modeling Suite.
BACKGROUND: Humans are exposed to tens of thousands of chemical substances that need to be assessed for their potential toxicity. Acute systemic toxicity testing serves as the basis for regulatory hazard classification, labeling, and risk management. However, it is cost- and time-prohibitive to evaluate all new and existing chemicals using traditional rodent acute toxicity tests. In silico models built using existing data facilitate rapid acute toxicity predictions without using animals. OBJECTIVES: The U.S. Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) Acute Toxicity Workgroup organized an international collaboration to develop in silico models for predicting acute oral toxicity based on five different end points: Lethal Dose 50 (LD50 value, U.S. Environmental Protection Agency hazard (four) categories, Globally Harmonized System for Classification and Labeling hazard (five) categories, very toxic chemicals [LD50 (LD50≤50mg/kg)], and nontoxic chemicals (LD50>2,000mg/kg). METHODS: An acute oral toxicity data inventory for 11,992 chemicals was compiled, split into training and evaluation sets, and made available to 35 participating international research groups that submitted a total of 139 predictive models. Predictions that fell within the applicability domains of the submitted models were evaluated using external validation sets. These were then combined into consensus models to leverage strengths of individual approaches. RESULTS: The resulting consensus predictions, which leverage the collective strengths of each individual model, form the Collaborative Acute Toxicity Modeling Suite (CATMoS). CATMoS demonstrated high performance in terms of accuracy and robustness when compared with in vivo results. DISCUSSION: CATMoS is being evaluated by regulatory agencies for its utility and applicability as a potential replacement for in vivo rat acute oral toxicity studies. CATMoS predictions for more than 800,000 chemicals have been made available via the National Toxicology Program's Integrated Chemical Environment tools and data sets (ice.ntp.niehs.nih.gov). The models are also implemented in a free, standalone, open-source tool, OPERA, which allows predictions of new and untested chemicals to be made. https://doi.org/10.1289/EHP8495
The ALICE experiment at the CERN LHC
ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 161626 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008