2,942 research outputs found
Scalar Induced Gravitational Waves from Finslerian Inflation and Pulsar Timing Arrays Observations
The recent data from NANOGrav provide strong evidence of the existence of the
\acp{SGWB}. We investigate \acp{SIGW} from Finslerian inflation as a potential
source of stochastic gravitational wave background. Small-scale (1
Mpc) statistically anisotropic primordial scalar perturbations can be generated
in Finslerian inflation. The second order \acp{SIGW} from Finslerian inflation
are also anisotropic on small scales. After spatially averaging the small-scale
anisotropic \acp{SIGW}, we obtain the large-scale isotropic \acp{SGWB}. We find
that the parameters of small-scale anisotropic primordial power spectrum
generated by Finslerian inflation affect the \acp{PTA} observations of
large-scale isotropic gravitational wave background
Regulation of the Late Onset alzheimer’s Disease Associated HLA-DQA1/DRB1 Expression
(Genome-wide Association Studies) GWAS have identified ∼42 late-onset Alzheimer’s disease (LOAD)-associated loci, each of which contains multiple single nucleotide polymorphisms (SNPs) in linkage disequilibrium (LD) and most of these SNPs are in the non-coding region of human genome. However, how these SNPs regulate risk gene expression remains unknown. In this work, by using a set of novel techniques, we identified 6 functional SNPs (fSNPs) rs9271198, rs9271200, rs9281945, rs9271243, and rs9271247 on the LOAD-associated HLA-DRB1/DQA1 locus and 42 proteins specifically binding to five of these 6 fSNPs. As a proof of evidence, we verified the allele-specific binding of GATA2 and GATA3, ELAVL1 and HNRNPA0, ILF2 and ILF3, NFIB and NFIC, as well as CUX1 to these five fSNPs, respectively. Moreover, we demonstrate that all these nine proteins regulate the expression of both HLA-DQA1 and HLA-DRB1 in human microglial cells. The contribution of HLA class II to the susceptibility of LOAD is discussed
Spinning Braid Group Representation and the Fractional Quantum Hall Effect
The path integral approach to representing braid group is generalized for
particles with spin. Introducing the notion of {\em charged} winding number in
the super-plane, we represent the braid group generators as homotopically
constrained Feynman kernels. In this framework, super Knizhnik-Zamolodchikov
operators appear naturally in the Hamiltonian, suggesting the possibility of
{\em spinning nonabelian} anyons. We then apply our formulation to the study of
fractional quantum Hall effect (FQHE). A systematic discussion of the ground
states and their quasi-hole excitations is given. We obtain Laughlin, Halperin
and Moore-Read states as {\em exact} ground state solutions to the respective
Hamiltonians associated to the braid group representations. The energy gap of
the quasi-excitation is also obtainable from this approach.Comment: (36 pages) e-mail [email protected]
Gigantism in unique biogenic magnetite at the Paleocene-Eocene Thermal Maximum
We report the discovery of exceptionally large biogenic magnetite crystals in clay-rich sediments spanning the Paleocene-Eocene Thermal Maximum (PETM) in a borehole at Ancora, New Jersey. Aside from previously-described abundant bacterial magnetofossils, electron microscopy reveals novel spearhead-like and spindle-like magnetite up to 4 μm long and hexaoctahedral prisms up to 1.4 μm long. Similar to magnetite produced by magnetotactic bacteria, these single-crystal particles exhibit chemical composition, lattice perfection, and oxygen isotopes consistent with an aquatic origin. Electron holography indicates single-domain magnetization despite their large crystal size. We suggest that the development of a thick suboxic zone with high iron bioavailability – a product of dramatic changes in weathering and sedimentation patterns driven by severe global warming – drove diversification of magnetite-forming organisms, likely including eukaryotes
Controlled Synthesis of Organic/Inorganic van der Waals Solid for Tunable Light-matter Interactions
Van der Waals (vdW) solids, as a new type of artificial materials that
consist of alternating layers bonded by weak interactions, have shed light on
fascinating optoelectronic device concepts. As a result, a large variety of vdW
devices have been engineered via layer-by-layer stacking of two-dimensional
materials, although shadowed by the difficulties of fabrication. Alternatively,
direct growth of vdW solids has proven as a scalable and swift way, highlighted
by the successful synthesis of graphene/h-BN and transition metal
dichalcogenides (TMDs) vertical heterostructures from controlled vapor
deposition. Here, we realize high-quality organic and inorganic vdW solids,
using methylammonium lead halide (CH3NH3PbI3) as the organic part (organic
perovskite) and 2D inorganic monolayers as counterparts. By stacking on various
2D monolayers, the vdW solids behave dramatically different in light emission.
Our studies demonstrate that h-BN monolayer is a great complement to organic
perovskite for preserving its original optical properties. As a result,
organic/h-BN vdW solid arrays are patterned for red light emitting. This work
paves the way for designing unprecedented vdW solids with great potential for a
wide spectrum of applications in optoelectronics
Genetic and phenotypic links between obesity and extracellular vesicles
Obesity has a highly complex genetic architecture, making it difficult to understand the genetic mechanisms, despite the large number of discovered loci via genome-wide association studies (GWAS). Omics techniques have provided a better resolution to view this problem. As a proxy of cell-level biology, extracellular vesicles (EVs) are useful for studying cellular regulation of complex phenotypes such as obesity. Here, in a well-established Scottish cohort, we utilized a novel technology to detect surface proteins across millions of single EVs in each individual’s plasma sample. Integrating the results with established obesity GWAS, we inferred 78 types of EVs carrying one or two of 12 surface proteins to be associated with adiposity-related traits such as waist circumference. We then verified that particular EVs’ abundance is negatively correlated with body adiposity, while no association with lean body mass. We also revealed that genetic variants associated with protein-specific EVs capture 2–4-fold heritability enrichment for blood cholesterol levels. Our findings provide evidence that EVs with specific surface proteins have phenotypic and genetic links to obesity and blood lipids, respectively, guiding future EV biomarker research
Controlled released naringin-loaded liposome/sucrose acetate isobutyrate hybrid depot for osteogenesis in vitro and in vivo
Introduction: A common problem in bone tissue engineering is that the burst release of active osteogenic factors is not beneficial for osteogenesis. This study aimed to prepare naringin (Ng) liposomes to reduce the burst release of Ng and improve new bone formation.Methods: We synthesized Ng liposomes using the thin-film hydration method. Drug-encapsulation efficacy experiments were conducted using the ultracentrifugation technique. The morphology and size distributions of freezedried liposomes were determined by transmission electron microscopy and dynamic light scattering. The Ng liposomes and Ng-lipo/sucrose acetate isobutyrate (SAIB) depots were characterized using Fourier transform infrared spectroscopy and in vitro release studies. After implantation of the Ng-lipo/SAIB depots, in vitro osteoblast-liposome interactions and in vivo osteogenesis were tested.Results: The formulation of freeze-dried Ng liposomes via an optimized recipe yielded nanosized (136.9 nm) negatively charged particles with a high encapsulation efficiency (~76.3%). Their chemical structure did not change after adding SAIB to the Ng liposomes. The burst release was reduced dramatically from 74.4% to 23.7%. In vivo, after 8 weeks, the new bone formation rate in the calvarial defects of Sprague-Dawley rats receiving Ng-lipo/SAIB was 57% compared with 25.18% in the control group (p = .0003).Discussion: Our results suggested that Ng-lipo/SAIB hybrid depots could serve as candidate materials for drug delivery in bone regeneration applications
Intracerebral delivery of 5-iodo-2'-deoxyuridine in combination with synchrotron stereotactic radiation for the therapy of the F98 glioma.
International audienceIodine-enhanced synchrotron stereotactic radiotherapy takes advantage of the radiation dose-enhancement produced by high-Z elements when irradiated with mono-energetic beams of synchrotron X-rays. In this study it has been investigated whether therapeutic efficacy could be improved using a thymidine analogue, 5-iodo-2'-deoxyuridine (IUdR), as a radiosentizing agent. IUdR was administered intracerebrally over six days to F98 glioma-bearing rats using Alzet osmotic pumps, beginning seven days after tumor implantation. On the 14th day, a single 15 Gy dose of 50 keV synchrotron X-rays was delivered to the brain. Animals were followed until the time of death and the primary endpoints of this study were the mean and median survival times. The median survival times for irradiation alone, chemotherapy alone or their combination were 44, 32 and 46 days, respectively, compared with 24 days for untreated controls. Each treatment alone significantly increased the rats' survival in comparison with the untreated group. Their combination did not, however, significantly improve survival compared with that of X-irradiation alone or chemotherapy alone. Further studies are required to understand why the combination of chemoradiotherapy was no more effective than X-irradiation alone
Exercise induces new cardiomyocyte generation in the adult mammalian heart.
Loss of cardiomyocytes is a major cause of heart failure, and while the adult heart has a limited capacity for cardiomyogenesis, little is known about what regulates this ability or whether it can be effectively harnessed. Here we show that 8 weeks of running exercise increase birth of new cardiomyocytes in adult mice (~4.6-fold). New cardiomyocytes are identified based on incorporation of 15N-thymidine by multi-isotope imaging mass spectrometry (MIMS) and on being mononucleate/diploid. Furthermore, we demonstrate that exercise after myocardial infarction induces a robust cardiomyogenic response in an extended border zone of the infarcted area. Inhibition of miR-222, a microRNA increased by exercise in both animal models and humans, completely blocks the cardiomyogenic exercise response. These findings demonstrate that cardiomyogenesis can be activated by exercise in the normal and injured adult mouse heart and suggest that stimulation of endogenous cardiomyocyte generation could contribute to the benefits of exercise
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