114 research outputs found
Entropy Estimate for Degenerate SDEs with Applications to Nonlinear Kinetic Fokker-Planck Equations
The relative entropy for two different degenerate diffusion processes is
estimated by using the Wasserstein distance of initial distributions and the
difference between coefficients. As applications, the entropy cost inequality
and exponential ergodicity in entropy are derived for distribution dependent
stochastic Hamiltonian systems associated with nonlinear kinetic Fokker Planck
equations.Comment: 22 page
Unraveling the role of ectopic thymic tissue in patients undergoing thymectomy for myasthenia gravis
Extended thymectomy has been considered the goal of surgery for myasthenia gravis (MG) mainly due to the existence of ectopic thymic tissue. Recently, ectopic thymic tissue has attracted increasing attention in patients with MG following thymectomy. However, the specific role of ectopic thymic tissue in patients with MG is still under debate. A systematic search of the literature was performed on PubMed and Medline according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISM) statement. Studies evaluating the rate of ectopic thymic tissue in patients with MG with or without thymoma were included. Extraction was performed for all eligible studies and the rate of ectopic thymic tissue at common locations was calculated. Eighteen out of fifty-nine studies were eligible for inclusion, of which ten studies reported the common locations of ectopic thymic tissue in mediastinal fat. Of these ten studies, the presence of ectopic thymic tissue was investigated in different anatomical locations in 882 patients, of whom, 509 patients (58%) have at least one positive location with the most common ones being anterior mediastinal fat, pericardiophrenic angles, aortopulmonary window, cervical region (pretracheal fat) and lateral to phrenic nerves. On the other hand, nine studies analyzed the influence of the presence of ectopic thymic tissue on the clinical outcomes of MG patients. Of these, six found that the presence of ectopic thymic tissue in MG patients is a significant predictor of poor outcome after thymectomy, however, the other three did not find a significance. Altogether, ectopic thymic tissue is likely to present in more than a half of patients undergoing thymectomy for MG. Besides, MG patients who have ectopic thymic tissue after thymectomy do not seem to have as good outcome as those who have not
TET2 Function in Hematopoietic Malignancies, Immune Regulation, and DNA Repair
Over the last decade, investigation of Ten-Eleven Translocation 2 (TET2) gene function and TET2 mutation have become of increasing interest in the field of hematology. This heightened interest was sparked by the seminal discoveries that (1) TET2 mutation is associated with development of hematological malignancies and that (2) the TET family of proteins is critical in promoting DNA demethylation and immune homeostasis. Since then, additional studies have begun to unravel the question “Does TET2 have additional biological functions in the regulation of hematopoiesis?” Here, we present a mini-review focused on the current understanding of TET2 in hematopoiesis, hematological malignancies, and immune regulation. Importantly, we highlight the critical function that TET2 facilitates in maintaining the stability of the genome. Based on our review of the literature, we provide a new hypothesis that loss of TET2 may lead to dysregulation of the DNA repair response, augment genome instability, and subsequently sensitize myeloid leukemia cells to PARP inhibitor treatment
β-Arrestin 2 Promotes Hepatocyte Apoptosis by Inhibiting AKT Protein
Recent studies reveal that multifunctional protein β-arrestin 2 (Arrb2) modulates cell apoptosis. Survival and various aspects of liver injury were investigated in WT and Arrb2KO mice after bile duct ligation (BDL). We found that deficiency of Arrb2 enhances survival and attenuates hepatic injury and fibrosis. Following BDL, Arrb2-deficient mice as compared with WT controls displayed a significant reduction of hepatocyte apoptosis as demonstrated by the TUNEL assay. Following BDL, the levels of phospho-Akt and phospho-glycogen synthase kinase 3β (GSK3β) in the livers were significantly increased in Arrb2 KO compared with WT mice, although p-p38 increased in WT but not in Arrb2-deficient mice. Inhibition of GSK3β following BDL decreases hepatic apoptosis and decreased p-p38 in WT mice but not in Arrb2 KO mice. Activation of Fas receptor with Jo2 reduces phospho-Akt and increases apoptosis in WT cells and WT mice but not in Arrb2-deficient cells and Arrb2-deficient mice. Consistent with direct interaction of Arrb2 with and regulating Akt phosphorylation, the expression of a full-length or N terminus but not the C terminus of Arrb2 reduces Akt phosphorylation and coimmunoprecipates with Akt. These results reveal that the protective effect of deficiency of Arrb2 is due to loss of negative regulation of Akt due to BDL and decreased downstream GSK3β and p38 MAPK signaling pathways
Resveratrol Regulates Mitochondrial Biogenesis and Fission/Fusion to Attenuate Rotenone-Induced Neurotoxicity
It has been confirmed that mitochondrial impairment may underlie both sporadic and familial Parkinson’s disease (PD). Mitochondrial fission/fusion and biogenesis are key processes in regulating mitochondrial homeostasis. Therefore, we explored whether the protective effect of resveratrol in rotenone-induced neurotoxicity was associated with mitochondrial fission/fusion and biogenesis. The results showed that resveratrol could not only promote mitochondrial mass and DNA copy number but also improve mitochondrial homeostasis and neuron function in rats and PC12 cells damaged by rotenone. We also observed effects with alterations in proteins known to regulate mitochondrial fission/fusion and biogenesis in rotenone-induced neurotoxicity. Therefore, our findings suggest that resveratrol may prevent rotenone-induced neurotoxicity through regulating mitochondrial fission/fusion and biogenesis
Energy loss enhancement of very intense proton beams in dense matter due to the beam-density effect
Thoroughly understanding the transport and energy loss of intense ion beams
in dense matter is essential for high-energy-density physics and inertial
confinement fusion. Here, we report a stopping power experiment with a
high-intensity laser-driven proton beam in cold, dense matter. The measured
energy loss is one order of magnitude higher than the expectation of individual
particle stopping models. We attribute this finding to the proximity of beam
ions to each other, which is usually insignificant for relatively-low-current
beams from classical accelerators. The ionization of the cold target by the
intense ion beam is important for the stopping power calculation and has been
considered using proper ionization cross section data. Final theoretical values
agree well with the experimental results. Additionally, we extend the stopping
power calculation for intense ion beams to plasma scenario based on Ohm's law.
Both the proximity- and the Ohmic effect can enhance the energy loss of intense
beams in dense matter, which are also summarized as the beam-density effect.
This finding is useful for the stopping power estimation of intense beams and
significant to fast ignition fusion driven by intense ion beams
Target density effects on charge tansfer of laser-accelerated carbon ions in dense plasma
We report on charge state measurements of laser-accelerated carbon ions in
the energy range of several MeV penetrating a dense partially ionized plasma.
The plasma was generated by irradiation of a foam target with laser-induced
hohlraum radiation in the soft X-ray regime. We used the tri-cellulose acetate
(CHO) foam of 2 mg/cm density, and -mm interaction
length as target material. This kind of plasma is advantageous for
high-precision measurements, due to good uniformity and long lifetime compared
to the ion pulse length and the interaction duration. The plasma parameters
were diagnosed to be T=17 eV and n=4 10 cm.
The average charge states passing through the plasma were observed to be higher
than those predicted by the commonly-used semiempirical formula. Through
solving the rate equations, we attribute the enhancement to the target density
effects which will increase the ionization rates on one hand and reduce the
electron capture rates on the other hand. In previsous measurement with
partially ionized plasma from gas discharge and z-pinch to laser direct
irradiation, no target density effects were ever demonstrated. For the first
time, we were able to experimentally prove that target density effects start to
play a significant role in plasma near the critical density of Nd-Glass laser
radiation. The finding is important for heavy ion beam driven high energy
density physics and fast ignitions.Comment: 7 pages, 4 figures, 35 conference
Single cell atlas for 11 non-model mammals, reptiles and birds.
The availability of viral entry factors is a prerequisite for the cross-species transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Large-scale single-cell screening of animal cells could reveal the expression patterns of viral entry genes in different hosts. However, such exploration for SARS-CoV-2 remains limited. Here, we perform single-nucleus RNA sequencing for 11 non-model species, including pets (cat, dog, hamster, and lizard), livestock (goat and rabbit), poultry (duck and pigeon), and wildlife (pangolin, tiger, and deer), and investigated the co-expression of ACE2 and TMPRSS2. Furthermore, cross-species analysis of the lung cell atlas of the studied mammals, reptiles, and birds reveals core developmental programs, critical connectomes, and conserved regulatory circuits among these evolutionarily distant species. Overall, our work provides a compendium of gene expression profiles for non-model animals, which could be employed to identify potential SARS-CoV-2 target cells and putative zoonotic reservoirs
Preliminary Investigation of Poly-Ether-Ether-Ketone Based on Fused Deposition Modeling for Medical Applications
Poly-ether-ether-ketone (PEEK) fabricated by fused deposition modeling for medical applications was evaluated in terms of mechanical strength and in vitro cytotoxicity in this study. Orthogonal experiments were firstly designed to investigate the significant factors on tensile strength. Nozzle temperature, platform temperature, and the filament diameter were tightly controlled for improved mechanical strength performance. These sensitive parameters affected the interlayer bonding and solid condition in the samples. Fourier transform infrared (FTIR) spectrometry analysis was secondly conducted to compare the functional groups in PEEK granules, filaments, and printed parts. In vitro cytotoxicity test was carried out at last, and no toxic substances were introduced during the printing process
Investigation on tee junction erosion caused by sand-carrying fracturing fluid
The high-speed flow of sand-carrying fracturing fluid through tee junctions causes severe erosion and affects the safety of the fracturing operation. This study improves the traditional computational fluid dynamics-discrete element method (CFD-DEM) to avoid the (dense particles) collision-leading abnormal penetration but also considers the influence of fracturing fluid viscosity on particle collisions. Then the tee junction erosion model under fracturing conditions is established and verified by experiments. The simulation analysis shows that with the increase of two-phase flow velocity and Stokes number, the dominant effect of particle motion and collision changes from viscous force to inertial force, and then the tee junction erosion position also changes.Nanyang Technological UniversityThis work was supported by Singapore Centre for 3D Printing (SC3DP) under the project “Acquisition and reconstruction of 3D CAD models for repair and re-engineering [grant numbers 001163-00010]; the National Natural Science Foundation of China [grant number 11972114]; and the Natural Science Foundation of Heilongjiang Province in China [grant number LH2020A00]
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