115 research outputs found
Constraints on Neutrino Velocities Revisited
With a minimally modified dispersion relation for neutrinos, we reconsider
the constraints on superluminal neutrino velocities from bremsstrahlung effects
in the laboratory frame. Employing both the direct calculation approach and the
virtual Z-boson approach, we obtain the generic decay width and energy loss
rate of a superluminal neutrino with general energy. The Cohen-Glashow's
analytical results for neutrinos with a relatively low energy are confirmed in
both approaches. We employ the survival probability instead of the terminal
energy to assess whether a neutrino with a given energy is observable or not in
the OPERA experiment. Moreover, using our general results we perform
systematical analyses on the constraints arising from the Super-Kamiokande and
IceCube experiments.Comment: RevTex4, 14 pages, 5 figures, minor corrections, version to appear in
Phys. Rev.
Mapping the Milky Way with LAMOST II: the stellar halo
The radial number density and flattening of the Milky Way's stellar halo is
measured with metal-poor ([Fe/H]) K giants from LAMOST
DR3, using a nonparametric method which is model independent and largely avoids
the influence of halo substucture. The number density profile is well described
by a single power law with index , and flattening that
varies with radius. The stellar halo traced by LAMOST K giants is more
flattened at smaller radii, and becomes nearly spherical at larger radii. The
flattening, , is about 0.64, 0.8, 0.96 at , 20 and 30 kpc (where
), respectively. Moreover, the
leading arm of the Sagittarius dwarf galaxy tidal stream in the north, and the
trailing arm in the south, are significant in the residual map of density
distribution. In addition, an unknown overdensity is identified in the residual
map at (R,Z)=(30,15) kpc.Comment: 16 pages, 24 figures, accepted by MNRA
GUPNet++: Geometry Uncertainty Propagation Network for Monocular 3D Object Detection
Geometry plays a significant role in monocular 3D object detection. It can be
used to estimate object depth by using the perspective projection between
object's physical size and 2D projection in the image plane, which can
introduce mathematical priors into deep models. However, this projection
process also introduces error amplification, where the error of the estimated
height is amplified and reflected into the projected depth. It leads to
unreliable depth inferences and also impairs training stability. To tackle this
problem, we propose a novel Geometry Uncertainty Propagation Network (GUPNet++)
by modeling geometry projection in a probabilistic manner. This ensures depth
predictions are well-bounded and associated with a reasonable uncertainty. The
significance of introducing such geometric uncertainty is two-fold: (1). It
models the uncertainty propagation relationship of the geometry projection
during training, improving the stability and efficiency of the end-to-end model
learning. (2). It can be derived to a highly reliable confidence to indicate
the quality of the 3D detection result, enabling more reliable detection
inference. Experiments show that the proposed approach not only obtains
(state-of-the-art) SOTA performance in image-based monocular 3D detection but
also demonstrates superiority in efficacy with a simplified framework.Comment: 18 pages, 9 figure
The Superluminal Neutrinos from Deformed Lorentz Invariance
We study two superluminal neutrino scenarios where \delta v\equiv (v-c)/c is
a constant. To be consistent with the OPERA, Borexino, and ICARUS experiments
and with the SN1987a observations, we assume that \delta v_{\nu} on the Earth
is about three order larger than that on the interstellar scale. To explain the
theoretical challenges from the Bremsstrahlung effects and pion decays, we
consider the deformed Lorentz invariance, and show that the superluminal
neutrino dispersion relations can be realized properly while the modifications
to the dispersion relations of the other Standard Model particles can be
negligible. In addition, we propose the deformed energy and momentum
conservation laws for a generic physical process. In Scenario I the momentum
conservation law is preserved while the energy conservation law is deformed. In
Scenario II the energy conservation law is preserved while the momentum
conservation law is deformed. We present the energy and momentum conservation
laws in terms of neutrino momentum in Scenario I and in terms of neutrino
energy in Scenario II. In such formats, the energy and momentum conservation
laws are exactly the same as those in the traditional quantum field theory with
Lorentz symmetry. Thus, all the above theoretical challenges can be
automatically solved. We show explicitly that the Bremsstrahlung processes are
forbidden and there is no problem for pion decays.Comment: RevTex4, 5 pages, comments and references adde
Transgenic studies reveal the positive role of LeEIL-1 in regulating shikonin biosynthesis in Lithospermum erythrorhizon hairy roots
Time-course accumulation of shikonin in four typical hairy root lines. Value of Ei-19 or EO-13 is significantly different from that of the control line WT-1 or EV-9 at each time point from 3 to 12 days, respectively (Student’s t-test, P < 0.05). (TIF 125 kb
α-Glucosidase Inhibitors From the Coral-Associated Fungus Aspergillus terreus
Nine novel butenolide derivatives, including four pairs of enantiomers, named (±)-asperteretones A–D (1a/1b–4a/4b), and a racemate, named asperteretone E (5), were isolated and identified from the coral-associated fungus Aspergillus terreus. All the structures were established based on extensive spectroscopic analyses, including HRESIMS and NMR data. The chiral chromatography analyses allowed the separation of (±)-asperteretones A–D, whose absolute configurations were further confirmed by experimental and calculated electronic circular dichroism (ECD) analysis. Structurally, compounds 2–5 represented the first examples of prenylated γ-butenolides bearing 2-phenyl-3-benzyl-4H-furan-1-one motifs, and their crucial biogenetically related metabolite, compound 1, was uniquely defined by an unexpected cleavage of oxygen bridge between C-1 and C-4. Importantly, (±)-asperteretal D and (4S)-4-decarboxylflavipesolide C were revised to (±)-asperteretones B (2a/2b) and D (4), respectively. Additionally, compounds 1a/1b–4a/4b and 5 were evaluated for the α-glucosidase inhibitory activity, and all these compounds exhibited potent inhibitory potency against α-glucosidase, with IC50 values ranging from 15.7 ± 1.1 to 53.1 ± 1.4 μM, which was much lower than that of the positive control acarbose (IC50 = 154.7 ± 8.1 μM), endowing them as promising leading molecules for the discovery of new α-glucosidase inhibitors for type-2 diabetes mellitus treatment
New Polyketides With Anti-Inflammatory Activity From the Fungus Aspergillus rugulosa
Two new polyketide compounds, asperulosins A and B (1–2), and one new prenylated small molecule, asperulosin C (3), along with nine known compounds (4–12), were isolated and identified from a fungus Aspergillus rugulosa. Their structures were extensively elucidated via HRESIMS, 1D, and 2D NMR analysis. The absolute configurations of the new compounds were determined by the comparison of their electronic circular dichroism (ECD), calculated ECD spectra, and the detailed discussion with those in previous reports. Structurally, compounds 1 and 2 belonged to the polyketide family and were from different origins. Compound 2 was constructed by five continuous quaternary carbon atoms, which occur rarely in natural products. All of the isolates were evaluated for anti-inflammatory activity against the production of nitric oxide (NO) in lipopolysaccharide (LPS)-induced RAW264.7 cells. Among those, compounds 1 and 5 showed a significant inhibitory effect on NO production with IC50 values of 1.49 ± 0.31 and 3.41 ± 0.85 μM, respectively. Additionally, compounds 1 and 5 markedly increased the secretion of anti-inflammatory cytokine IL10 while suppressing the secretion of pro-inflammatory cytokines IL6, TNF-α, IFN-γ, MCP-1, and IL12. Besides, 1 and 5 inhibited the transcription level of pro-inflammatory macrophage markers IL6, IL1β, and TNF-α while remarkably elevating the anti-inflammatory factor IL10 and M2 macrophage markers ARG1 and CD206. Moreover, 1 and 5 restrained the expression and nuclear translocation of NF-κB, as well as its downstream signaling proteins COX-2 and iNOS. All these results suggest that 1 and 5 have potential as anti-inflammatory agents, with better or comparable activities than those of the positive control, dexamethasone
Key candidate genes and pathways in T lymphoblastic leukemia/lymphoma identified by bioinformatics and serological analyses
T-cell acute lymphoblastic leukemia (T-ALL)/T-cell lymphoblastic lymphoma (T-LBL) is an uncommon but highly aggressive hematological malignancy. It has high recurrence and mortality rates and is challenging to treat. This study conducted bioinformatics analyses, compared genetic expression profiles of healthy controls with patients having T-ALL/T-LBL, and verified the results through serological indicators. Data were acquired from the GSE48558 dataset from Gene Expression Omnibus (GEO). T-ALL patients and normal T cells-related differentially expressed genes (DEGs) were investigated using the online analysis tool GEO2R in GEO, identifying 78 upregulated and 130 downregulated genes. Gene Ontology (GO) and protein-protein interaction (PPI) network analyses of the top 10 DEGs showed enrichment in pathways linked to abnormal mitotic cell cycles, chromosomal instability, dysfunction of inflammatory mediators, and functional defects in T-cells, natural killer (NK) cells, and immune checkpoints. The DEGs were then validated by examining blood indices in samples obtained from patients, comparing the T-ALL/T-LBL group with the control group. Significant differences were observed in the levels of various blood components between T-ALL and T-LBL patients. These components include neutrophils, lymphocyte percentage, hemoglobin (HGB), total protein, globulin, erythropoietin (EPO) levels, thrombin time (TT), D-dimer (DD), and C-reactive protein (CRP). Additionally, there were significant differences in peripheral blood leukocyte count, absolute lymphocyte count, creatinine, cholesterol, low-density lipoprotein, folate, and thrombin times. The genes and pathways associated with T-LBL/T-ALL were identified, and peripheral blood HGB, EPO, TT, DD, and CRP were key molecular markers. This will assist the diagnosis of T-ALL/T-LBL, with applications for differential diagnosis, treatment, and prognosis
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