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The Interaction of Obesity and Age and their effect on Adipose Tissue Metabolism in the Mouse
Numerous studies have investigated how bulk lipid metabolism is influenced in obesity and in particular how the composition of triglycerides found in the cytosol change with increased adipocyte expansion. However, in part reflecting the analytical challenge the composition of cell membranes, and in particular glycerophospholipids, an important membrane component, have been seldom investigated. Cell membrane components contribute to a variety of cellular processes including maintaining organelle functionality, providing an optimized environment for numerous proteins and providing important pools for metabolites, such as choline for one-carbon metabolism and S-adenosylmethionine for DNA methylation. Here, I have conducted a comprehensive lipidomic and transcriptomic study of white adipose tissue in mice that become obese either through genetic modification (ob/ob genotype), diet (high-fat diet) or a combination of the two across the life course. Specifically, I demonstrated that the changes in triglyceride metabolism that dominate the overall lipid composition of white adipose tissue were distinct from the compositional changes of glycerophospholipids. These latter lipids became more unsaturated to maintain the fluidity and normal function of the membrane in the initiation of obesity but then turned saturated after long-term administration of HFD and aging. This suggests that while triglycerides within the adipose tissue may be a relatively inert store of lipids, the compositional changes occur in cell membranes with more far-reaching functional consequences in both obesity and aging. The two-phase change of phospholipids can be correlated well with transcriptional and one-carbon metabolic changes within the adipocytes. The transcriptomic study demonstrated that the lipid metabolic pathways regulated by the peroxisome, AMPK, insulin and PPARγ signaling were activated in the initiation of obesity but inhibited in the adipose tissue of old ob/ob mice along with up-regulated inflammation pathways. The brown and white adipose tissue of PPARα-knock-out mice were also studied by lipidomic tools to get a deeper understanding of the effect of the peroxisome and PPAR system on adipose tissue and lipid metabolism during obesity. Most of the lipids were increased and became more saturated and shorter in adipose tissues of PPARα null mice, which is in good accordance with the results of the former animal study. In conclusion, my work using different rodent models and multi-omics techniques demonstrated a protective metabolic mechanism activated in the initiation but impaired at the end of the processes of obesity and aging, which could be an explanation of the similarity of obesity and aging in terms of high incidence of the metabolic syndrome and related diseases
Domain wall brane in a reduced Born-Infeld- theory
The Born-Infeld theory is reduced from the Born-Infeld determinantal
gravity in Weitzenb\"ock spacetime. We investigate a braneworld scenario in
this theory and obtain an analytic domain wall solution by utilizing the
first-order formalism. The model is stable against the linear tensor
perturbation. It is shown that the massless graviton is localized on the brane,
but the continuous massive gravitons are non-localized and will generate a tiny
correction with the behavior of to the Newtonian potential.
The four-dimensional teleparallel gravity is recovered as an effective infrared
theory on the brane. As a physical application, we consider the
(quasi-)localization property of spin-1/2 Dirac fermion in this model.Comment: 9 pages, 2 figures, published versio
Mode of anesthesia for cesarean delivery with pernicious placenta previa — a retrospective study
Objectives: Anesthesia for cesarean delivery in parturients diagnosed with pernicious placenta previa remains controversial. This study aimed to review pernicious placenta previa cases to evaluate anesthetic management strategies. Material and methods: This retrospective analysis included patients who underwent cesarean delivery (CD) for pernicious placenta previa at the Affiliated Hospital of Zunyi Medical University between December 1, 2012 and November 31, 2017. Patient demographic data, obstetric characteristics, anesthetic management, and maternal outcomes were extracted from the hospital’s computerized database. Results: In all, 61 consecutive cases of pernicious placenta previa were identified among 9512 cesarean deliveries. General anesthesia was performed on 27 of the 61 patients (44.3%). Among GA group, 16 (59.3%) had placenta accreta, 8 of whom required cesarean hysterectomy. Also, 13 of the 27 (48.1%) GA patients required transfer to the intensive care unit. The other 34 patients (55.7%) were given regional anesthesia, 9 of whom were converted to general anesthesia due to excessive bleeding and prolonged operation times. Statistical results indicated that regional anesthesia was associated with a significantly shorter operation time, less perioperative blood loss, fewer intraoperative red blood cell transfusions, and a lower incidence of complications. Conclusions: Anesthetic management is important for parturients with pernicious placenta previa. Although regional anesthesia was our preferred method for these patients, general anesthesia is safe for patients with pernicious placenta previa who experience massive blood loss and prolonged operation times
Ethyl 6-amino-5-cyano-2-methyl-4-propyl-4H-pyran-3-carboxylÂate
The pyran ring of the title compound, C13H18N2O3, is almost planar (r.m.s. deviation = 0.059 Å). The crystal packing is stabilized by N—H⋯O and N—H⋯N hydrogen bonds
Varying magnetism in the lattice distorted Y2NiIrO6 and La2NiIrO6
We investigate the electronic and magnetic properties of the newly
synthesized double perovskites YNiIrO and LaNiIrO,
using density functional calculations, crystal field theory, superexchange
pictures, and Monte Carlo simulations. We find that both systems are
antiferromagnetic (AFM) Mott insulators, with the high-spin Ni
() and the low-spin Ir
() configurations. We address that their lattice distortion induces
- orbital mixing and thus enables the normal Ni-Ir
charge excitation with the electron hopping from the Ir `' to Ni
`' orbitals, which promotes the AFM Ni-Ir coupling.
Therefore, the increasing - mixing accounts for the enhanced
from the less distorted LaNiIrO to the more distorted
YNiIrO. Moreover, our test calculations find that in the otherwise
ideally cubic YNiIrO, the Ni-Ir charge excitation is
forbidden, and only the abnormal Ni-Ir excitation gives a weakly
ferromagnetic (FM) behavior. Furthermore, we find that owing to the crystal
field splitting, Hund exchange, and broad band formation in the highly
coordinated fcc sublattice, Ir ions are not in the
state but in the state carrying a finite orbital moment by spin-orbit
coupling (SOC). This work clarifies the varying magnetism in YNiIrO
and LaNiIrO associated with the lattice distortions.Comment: 7 pages, 7 figures, 1 tabl
Dynamically tunable electromagnetically induced transparency-like metamaterial structure based on polarization sensitivity
In this paper, we propose a plasmon-induced transparency (PIT) metamaterial
structure composed of Ag nanomaterials with polarization sensitivity. The
metamaterial model consists of three bright modes with different resonant
frequencies. The optical properties of the structure are further investigated
using finite difference time domain (FDTD) method. The results show that the
conversion between single-band PIT and dual-band PIT effects can be achieved by
changing the polarization degree of the incident light, the number of
transparent windows can be changed from one to two, and the process is
accompanied by the conversion of bright and dark modes and the change of the
resonance wavelength of the transmission peak. In addition, When the light is
polarized in the Y-direction, the two transparency windows have different
refractive index sensitivities, with FOM values of 5.94/RIU and 5.65/RIU,
respectively
- …