1,581 research outputs found
Life fingerprints of nuclear reactions in the body of animals
Nuclear reactions are a very important natural phenomenon in the universe. On the earth, cosmic rays constantly cause nuclear reactions. High energy beams created by medical devices also induce nuclear reactions in the human body. The biological role of these nuclear reactions is unknown. Here we show that the in vivo biological systems are exquisite and sophisticated by nature in influence on nuclear reactions and in resistance to radical damage in the body of live animals. In this study, photonuclear reactions in the body of live or dead animals were induced with 50-MeV irradiation. Tissue nuclear reactions were detected by positron emission tomography (PET) imaging of the induced beta+ activity. We found the unique tissue "fingerprints" of beta+ (the tremendous difference in beta+ activities and tissue distribution patterns among the individuals) are imprinted in all live animals. Within any individual, the tissue "fingerprints" of 15O and 11C are also very different. When the animal dies, the tissue "fingerprints" are lost. The biochemical, rather than physical, mechanisms could play a critical role in the phenomenon of tissue "fingerprints". Radiolytic radical attack caused millions-fold increases in 15O and 11C activities via different biochemical mechanisms, i.e. radical-mediated hydroxylation and peroxidation respectively, and more importantly the bio-molecular functions (such as the chemical reactivity and the solvent accessibility to radicals). In practice biologically for example, radical attack can therefore be imaged in vivo in live animals and humans using PET for life science research, disease prevention, and personalized radiation therapy based on an individual's bio-molecular response to ionizing radiation
Gapless topological Fulde-Ferrell superfluidity in spin-orbit coupled Fermi gases
Topological superfluids usually refer to a superfluid state which is gapped
in the bulk but metallic at the boundary. Here we report that a gapless,
topologically non-trivial superfluid with inhomogeneous Fulde-Ferrell pairing
order parameter can emerge in a two-dimensional spin-orbit coupled Fermi gas,
in the presence of both in-plane and out-of-plane Zeeman fields. The
Fulde-Ferrell pairing - induced by the spin-orbit coupling and in-plane Zeeman
field - is responsible for this gapless feature. This exotic superfluid has a
significant Berezinskii-Kosterlitz-Thouless (BKT) transition temperature and
has robust Majorana edge modes against disorder owing to its topological
nature.Comment: 5 pages, 5 figures; add the results on the critical BKT temperature
and superfluid density, as well as the discussion on the robustness of the
chiral edge states against disorde
Semi-supervised Counting via Pixel-by-pixel Density Distribution Modelling
This paper focuses on semi-supervised crowd counting, where only a small
portion of the training data are labeled. We formulate the pixel-wise density
value to regress as a probability distribution, instead of a single
deterministic value. On this basis, we propose a semi-supervised crowd-counting
model. Firstly, we design a pixel-wise distribution matching loss to measure
the differences in the pixel-wise density distributions between the prediction
and the ground truth; Secondly, we enhance the transformer decoder by using
density tokens to specialize the forwards of decoders w.r.t. different density
intervals; Thirdly, we design the interleaving consistency self-supervised
learning mechanism to learn from unlabeled data efficiently. Extensive
experiments on four datasets are performed to show that our method clearly
outperforms the competitors by a large margin under various labeled ratio
settings. Code will be released at
https://github.com/LoraLinH/Semi-supervised-Counting-via-Pixel-by-pixel-Density-Distribution-Modelling.Comment: This is the technical report of a paper that was submitted to IEEE
Transactions and is now under revie
Modeling Multiple Views via Implicitly Preserving Global Consistency and Local Complementarity
While self-supervised learning techniques are often used to mining implicit
knowledge from unlabeled data via modeling multiple views, it is unclear how to
perform effective representation learning in a complex and inconsistent
context. To this end, we propose a methodology, specifically consistency and
complementarity network (CoCoNet), which avails of strict global inter-view
consistency and local cross-view complementarity preserving regularization to
comprehensively learn representations from multiple views. On the global stage,
we reckon that the crucial knowledge is implicitly shared among views, and
enhancing the encoder to capture such knowledge from data can improve the
discriminability of the learned representations. Hence, preserving the global
consistency of multiple views ensures the acquisition of common knowledge.
CoCoNet aligns the probabilistic distribution of views by utilizing an
efficient discrepancy metric measurement based on the generalized sliced
Wasserstein distance. Lastly on the local stage, we propose a heuristic
complementarity-factor, which joints cross-view discriminative knowledge, and
it guides the encoders to learn not only view-wise discriminability but also
cross-view complementary information. Theoretically, we provide the
information-theoretical-based analyses of our proposed CoCoNet. Empirically, to
investigate the improvement gains of our approach, we conduct adequate
experimental validations, which demonstrate that CoCoNet outperforms the
state-of-the-art self-supervised methods by a significant margin proves that
such implicit consistency and complementarity preserving regularization can
enhance the discriminability of latent representations.Comment: Accepted by IEEE Transactions on Knowledge and Data Engineering
(TKDE) 2022; Refer to https://ieeexplore.ieee.org/document/985763
Traveling kink oscillations of coronal loops launched by a solar flare
We investigate the traveling kink oscillation triggered by a solar flare on
2022 September 29. The observational data is mainly measured by the Solar Upper
Transition Region Imager (SUTRI), the Atmospheric Imaging Assembly (AIA), and
the Spectrometer/Telescope for Imaging X-rays (STIX). The transverse
oscillations with apparent decaying in amplitudes, which are nearly
perpendicular to the oscillating loop, are observed in passbands of SUTRI 465
A, AIA 171 A, and 193 A. The decaying oscillation is launched by a solar flare
erupted closely to one footpoint of coronal loops, and then it propagates along
several loops. Next, the traveling kink wave is evolved to a standing kink
oscillation. To the best of our knowledge, this is the first report of the
evolution of a traveling kink pulse to a standing kink wave along coronal
loops. The standing kink oscillation along one coronal loop has a similar
period of about 6.3 minutes at multiple wavelengths, and the decaying time is
estimated to about 9.6-10.6 minutes. Finally, two dominant periods of 5.1
minutes and 2.0 minutes are detected in another oscillating loop, suggesting
the coexistence of the fundamental and third harmonics.Comment: 8 pages, 8 figures, accepted by A&
In vitro cellular uptake of evodiamine and rutaecarpine using a microemulsion
Yong-Tai Zhang, Zhe-Bin Huang, Su-Juan Zhang, Ji-Hui Zhao, Zhi Wang, Ying Liu, Nian-Ping FengDepartment of Pharmaceutics, Shanghai University of Traditional Chinese Medicine, Shanghai, The People's Republic of ChinaObjective: To investigate the cellular uptake of evodiamine and rutaecarpine in a microemulsion in comparison with aqueous suspensions and tinctures.Materials and methods: A microemulsion was prepared using the dropwise addition method. Mouse skin fibroblasts were cultured in vitro to investigate the optimal conditions for evodiamine and rutaecarpine uptake with different drug concentrations and administration times. Under optimal conditions, the cellular uptake of microemulsified drugs was assayed and compared to tinctures and aqueous suspensions. Rhodamine B labeling and laser scanning confocal microscopy (LSCM) were used to explore the distribution of fluorochrome transferred with the microemulsion in fibroblasts. Cellular morphology was also investigated, using optical microscopy to evaluate microemulsion-induced cellular toxicity.Results: The maximum cellular drug uptake amounts were obtained with a 20% concentration (v/v) of microemulsion and an 8 hour administration time. Drug uptake by mouse skin fibroblasts was lowest when the drugs were loaded in microemulsion. After incubation with rhodamine B-labeled microemulsion for 8 hours, the highest fluorescence intensity was achieved, and the fluorochrome was primarily distributed in the cytochylema. No obvious cellular morphologic changes were observed with the administration of either the microemulsion or the aqueous suspension; for the tincture group, however, massive cellular necrocytosis was observed.Conclusion: The lower cellular uptake with microemulsion may be due to the fact that most of the drug loaded in the microemulsion vehicle was transported via the intercellular space, while a small quantity of free drug (released from the vehicle) was ingested through transmembrane transport. Mouse skin fibroblasts rarely endocytosed evodiamine and rutaecarpine with a microemulsion as the vehicle. The microemulsion had no obvious effect on cellular morphology, suggesting there is little or no cellular toxicity associated with the administration of microemulsion on mouse skin fibroblasts.Keywords: mouse skin fibroblasts, evodiamine, rutaecarpine, microemulsion, cellular uptake, in vitr
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