794 research outputs found
Horndeski Gravity and the Violation of Reverse Isoperimetric Inequality
We consider Einstein-Horndeski-Maxwell gravity, together with a cosmological
constant and multiple Horndeski axions. We construct charged AdS planar black
holes in general dimensions where the Horndeski anxions span over the planar
directions. We analyse the thermodynamics and obtain the black hole volumes. We
show that the reverse isoperimetric inequality can be violated, implying that
these black holes can store information more efficiently than the Schwarzschild
black hole.Comment: Latex, 25 pages, 1 figure, references adde
Variations in photoprotective potential along gradients of leaf development and plant succession in subtropical forests under contrasting irradiances
The successful development of photosynthetic organs is the basis of plant growth and community development. To reveal photo-acclimation to high irradiance in tree species during the course of leaf development and plant succession of subtropical forests, photosynthetic efficiency and photoprotective compounds were analyzed in young and mature leaves of three mid-successional tree species (Castanopsis fissa, Castanopsis chinensis and Schima superba) and three late-successional tree species (Machilus chinensis, Cryptocarya chinensis and Cryptocarya concinna), grown in 100% full sunlight (FL) or 30% of FL (low light, LL). Young leaves of the two species groups exhibited lower chlorophyll (Chl) content, Rubisco content, net photosynthetic rate (Pn), carboxylation efficiency (CE), effective photochemical yield (ΦPSII), photorespiratory electron flow (JO), but higher dark respiration (Rd), and ratios of carotenoids/chlorophylls (Car/Chl), anthocyanins/chlorophylls (Anth/Chl), flavonoids/chlorophylls (Flav/Chl), phenols/chlorophylls (Phen/Chl) and total antioxidant capacity/chlorophylls (TAC/Chl) than those of mature leaves, regardless of growth irradiance. Young leaves of both species groups demonstrated a higher flexibility of Anth/Chl, Flav/Chl, Phen/Chl and TAC/Chl in response to different light conditions than mature leaves. Flav/Chl in young leaves of late-successional group was remarkably higher than that of mid-successional group under the same light conditions. There was a negative correlation between antioxidant-dependent photoprotective potential and photosynthetic efficiency in young and mature leaves of the six tree species grown under either FL or LL. Our results explain partial mechanisms that lie behind the replacement of communities in subtropical forests: highly integrated photoprotective potential allows young leaves of shade-tolerant late-successional species to develop smoothly into mature organs under high irradiance.This work was funded by the National Natural Science Foundation
of China (31570398, 31270287). The study was also supported by the
key programme of Guangdong Province Natural Science Foundation
(2015A030311023)
Direct Visualization of Irreducible Ferrielectricity in Crystals
In solids, charge polarity can one-to-one correspond to spin polarity
phenomenologically, e.g. ferroelectricity/ferromagnetism,
antiferroelectricity/antiferromagnetism, and even
dipole-vortex/magnetic-vortex, but ferrielectricity/ferrimagnetism kept telling
a disparate story in microscopic level. Since the definition of a charge dipole
involves more than one ion, there may be multiple choices for a dipole unit,
which makes most ferrielectric orders equivalent to ferroelectric ones, i.e.
this ferrielectricity is not necessary to be a real independent branch of
polarity. In this work, by using the spherical aberration-corrected scanning
transmission electron microscope, we visualize a nontrivial ferrielectric
structural evolution in BaFe2Se3, in which the development of two polar
sub-lattices is out-of-sync, for which we term it as irreducible
ferrielectricity. Such irreducible ferrielectricity leads to a non-monotonic
behavior for the temperature-dependent polarization, and even a compensation
point in the ordered state. Our finding unambiguously distinguishes
ferrielectrics from ferroelectrics in solids.Comment: 15 figure
Modeling realistic Earth matter density for CP violation in neutrino oscillation
We examine the effect of a more realistic Earth matter density model which
takes into account of the local density variations along the baseline of a
possi ble 2100 km very long baseline neutrino oscillation experiment. Its
influence to the measurement of CP violation is investigated and a comparison
with the commonly used global density models made. Significant differences are
found in the comparison of the results of the different density models.Comment: 16 pages, 8 figure
Ising Superconductivity and Quantum Phase Transition in Macro-Size Monolayer NbSe2
Two-dimensional (2D) transition metal dichalcogenides (TMDs) have a range of
unique physics properties and could be used in the development of electronics,
photonics, spintronics and quantum computing devices. The mechanical
exfoliation technique of micro-size TMD flakes has attracted particular
interest due to its simplicity and cost effectiveness. However, for most
applications, large area and high quality films are preferred. Furthermore,
when the thickness of crystalline films is down to the 2D limit (monolayer),
exotic properties can be expected due to the quantum confinement and symmetry
breaking. In this paper, we have successfully prepared macro-size atomically
flat monolayer NbSe2 films on bilayer graphene terminated surface of
6H-SiC(0001) substrates by molecular beam epitaxy (MBE) method. The films
exhibit an onset superconducting critical transition temperature above 6 K, 2
times higher than that of mechanical exfoliated NbSe2 flakes. Simultaneously,
the transport measurements at high magnetic fields reveal that the parallel
characteristic field Bc// is at least 4.5 times higher than the paramagnetic
limiting field, consistent with Zeeman-protected Ising superconductivity
mechanism. Besides, by ultralow temperature electrical transport measurements,
the monolayer NbSe2 film shows the signature of quantum Griffiths singularity
when approaching the zero-temperature quantum critical point
Osteocalcin Ameliorates Motor Dysfunction in a 6-Hydroxydopamine-Induced Parkinson’s Disease Rat Model Through AKT/GSK3β Signaling
Osteoblasts derived osteocalcin (OCN) is recently reported to be involved in dopaminergic neuronal development. As dopaminergic neuronal injury in the substantia nigra (SN) is a pathological hallmark of Parkinson’s disease (PD), we investigated whether OCN could exert protective effects on 6-hydroxydopamine (6-OHDA)-induced PD rat model. Our data showed that the OCN level in the cerebrospinal fluid (CSF) in PD rat models was significantly lower than that in controls. Intervention with OCN could improve the behavioral dysfunction in PD rat models and reduce the tyrosine hydroxylase (TH) loss in the nigrostriatal system. In addition, OCN could inhibit the astrocyte and microglia proliferation in the SN of PD rats. In vitro studies showed that OCN significantly ameliorated the neurotoxicity of 6-OHDA through the AKT/GSK3β signaling pathway. In summary, OCN plays a protective role against parkinsonian neurodegeneration in the PD rat model, suggesting a potential therapeutic use of OCN in PD
Parallel momentum distribution of the Si fragments from P
Distribution of the parallel momentum of Si fragments from the breakup
of 30.7 MeV/nucleon P has been measured on C targets. The distribution
has the FWHM with the value of 110.5 23.5 MeV/c which is consistent
quantitatively with Galuber model calculation assuming by a valence proton in
P. The density distribution is also predicted by Skyrme-Hartree-Fock
calculation. Results show that there might exist the proton-skin structure in
P.Comment: 4 pages, 4 figure
Baseline serum uric acid level is associated with progression-free survival, disease control rate, and safety in postoperative patients with colorectal cancer treated by FOLFOX, FOLFIRI, or XELOX
BackgroundHigh serum uric acid (SUA) levels increase the risk of overall cancer morbidity and mortality, particularly for digestive malignancies. Nevertheless, the correlation between SUA level and clinical outcomes of the postoperative patients with colorectal cancer (CRC) treated by chemotherapy is unclear. This study aimed at exploring the relationship between baseline SUA level and progression-free survival (PFS), disease control rate (DCR), and safety in postoperative CRC patients receiving chemotherapy.Patients and MethodsWe conducted a retrospective study to evaluate the relationship between baseline SUA level and PFS, DCR, and incidence of serious adverse events of 736 postoperative CRC patients treated with FOLFOX, FOLFIRI or XELOX at our center.ResultsData from our center suggested that high baseline SUA level is linked to poor PFS in non-metastatic CRC patients using FOLFOX (HR=2.59, 95%CI: 1.29-11.31, p=0.018) and in male patients using FOLFIRI (HR=3.77, 95%CI: 1.57-39.49, p=0.012). In patients treated by FOLFIRI, a high SUA is also linked to a low DCR (p=0.035). In patients using FOLFOX, high baseline SUA level is also linked to a high incidence of neutropenia (p=0.0037). For patients using XELOX, there is no significant correlation between SUA level and PFS, effectiveness, or safety.ConclusionsThese findings imply that a high SUA level is a promising biomarker associated with poor PFS, DCR and safety of postoperative CRC patients when treated with FOLFOX or FOLFIRI
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