1,312 research outputs found
Fractional Liouville and BBGKI Equations
We consider the fractional generalizations of Liouville equation. The
normalization condition, phase volume, and average values are generalized for
fractional case.The interpretation of fractional analog of phase space as a
space with fractal dimension and as a space with fractional measure are
discussed. The fractional analogs of the Hamiltonian systems are considered as
a special class of non-Hamiltonian systems. The fractional generalization of
the reduced distribution functions are suggested. The fractional analogs of the
BBGKI equations are derived from the fractional Liouville equation.Comment: 20 page
Isolation and characterization of membranes from bovine liver which are highly enriched in mannose 6-phosphate receptors.
Photocurrent in nanostructures with asymmetric antidots
The steady current induced by electromagnetic field in a 2D system with
asymmetric scatterers is studied. The scatterers are assumed to be oriented
cuts with one diffusive and another specular sides. Besides, the existence of
isotropic impurity scatterers is assumed. This simple model simulates the
lattice of half-disk which have been studied numerically recently. The model
allows the exact solution in the framework of the kinetic equation. The static
current response in the second order of electric field is obtained. The
photogalvanic tensor contains both responses to linear and circular
polarization of electromagnetic field. The model possesses non-analyticity with
regards to the rate of impurity scattering.Comment: 9 pages, 6 figure
Linguistics
Contains reports on five research projects.National Institute of Mental Health (Grant 5 PO1 MH-13390-04
Fractional Systems and Fractional Bogoliubov Hierarchy Equations
We consider the fractional generalizations of the phase volume, volume
element and Poisson brackets. These generalizations lead us to the fractional
analog of the phase space. We consider systems on this fractional phase space
and fractional analogs of the Hamilton equations. The fractional generalization
of the average value is suggested. The fractional analogs of the Bogoliubov
hierarchy equations are derived from the fractional Liouville equation. We
define the fractional reduced distribution functions. The fractional analog of
the Vlasov equation and the Debye radius are considered.Comment: 12 page
Sirtuin 3 Downregulation in Mycobacterium tuberculosis-Infected Macrophages Reprograms Mitochondrial Metabolism and Promotes Cell Death
Mycobacterium tuberculosis induces metabolic reprogramming in macrophages like the Warburg effect. This enhances antimicrobial performance at the expense of increased inflammation, which may promote a pathogen-permissive host environment. Since the NAD(+)-dependent protein deacetylase Sirtuin 3 (SIRT3) is an important regulator of mitochondrial metabolism and cellular redox homeostasis, we hypothesized that SIRT3 modulation mediates M. tuberculosis-induced metabolic reprogramming. Infection of immortalized and primary murine macrophages resulted in reduced levels of SIRT3 mRNA and protein and perturbation of SIRT3-regulated enzymes in the tricarboxylic acid cycle, electron transport chain, and glycolytic pathway. These changes were associated with increased reactive oxygen species and reduced antioxidant scavenging, thereby triggering mitochondrial stress and macrophage cell death. Relevance to tuberculosis disease in vivo was indicated by greater bacterial burden and immune pathology in M. tuberculosis-infected Sirt3 (-/-) mice. CD11b(+) lung leukocytes isolated from infected Sirt3(-/-) mice showed decreased levels of enzymes involved in central mitochondrial metabolic pathways, along with increased reactive oxygen species. Bacterial burden was also greater in lungs of LysM(cre)Sirt3(L2/L2) mice, demonstrating the importance of macrophage-specific SIRT3 after infection. These results support the model of SIRT3 as a major upstream regulatory factor, leading to metabolic reprogramming in macrophages by M. tuberculosis
IMPORTANCE Tuberculosis, the disease caused by the bacterium M. tuberculosis, remains one of the top 10 causes of death worldwide. Macrophages, the first cells to encounter M. tuberculosis and critical for defense against infection, are hijacked by M. tuberculosis as a protected growth niche. M. tuberculosis-infected macrophages undergo metabolic reprogramming where key mitochondrial pathways are modulated, but the mechanisms driving this metabolic shift is unknown. Our study demonstrates that M. tuberculosis downregulates Sirtuin 3 (SIRT3), an important regulator of mitochondrial metabolism, leading to SIRT3-dependent transcriptional downregulation of mitochondrial metabolic proteins, which is followed by oxidative stress and macrophage necrosis. This study identifies SIRT3 modulation as a key event in M. tuberculosis-induced metabolic reprograming in macrophages that defend against tuberculosis
Factors Affecting European Farmers’Participation in Biodiversity Policies
This article reports the major findings from an interdisciplinary research project that synthesises key insights into farmers’ willingness and ability to co-operate with biodiversity policies. The results of the study are based on an assessment of about 160
publications and research reports from six EU member states and from international comparative research.We developed a conceptual framework to systematically review the
existent literature relevant for our purposes. This framework provides a common structure for analysing farmers’ perspectives regarding the introduction into farming practices of measures relevant to biodiversity. The analysis is coupled and contrasted with a survey of experts. The results presented above suggest that it is important to view support for practices oriented towards biodiversity protection not in a static sense – as a situation determined by one or several influencing factors – but rather as a process marked by interaction. Financial compensation and incentives function as a necessary, though
clearly not sufficient condition in this process
SILAC-based phosphoproteomics reveals an inhibitory role of KSR1 in p53 transcriptional activity via modulation of DBC1
BACKGROUND
We have previously identified kinase suppressor of ras-1 (KSR1) as a potential regulatory gene in breast cancer. KSR1, originally described as a novel protein kinase, has a role in activation of mitogen-activated protein kinases. Emerging evidence has shown that KSR1 may have dual functions as an active kinase as well as a scaffold facilitating multiprotein complex assembly. Although efforts have been made to study the role of KSR1 in certain tumour types, its involvement in breast cancer remains unknown.
METHODS
A quantitative mass spectrometry analysis using stable isotope labelling of amino acids in cell culture (SILAC) was implemented to identify KSR1-regulated phosphoproteins in breast cancer. In vitro luciferase assays, co-immunoprecipitation as well as western blotting experiments were performed to further study the function of KSR1 in breast cancer.
RESULTS
Of significance, proteomic analysis reveals that KSR1 overexpression decreases deleted in breast cancer-1 (DBC1) phosphorylation. Furthermore, we show that KSR1 decreases the transcriptional activity of p53 by reducing the phosphorylation of DBC1, which leads to a reduced interaction of DBC1 with sirtuin-1 (SIRT1); this in turn enables SIRT1 to deacetylate p53.
CONCLUSION
Our findings integrate KSR1 into a network involving DBC1 and SIRT1, which results in the regulation of p53 acetylation and its transcriptional activity
Big Entropy Fluctuations in Nonequilibrium Steady State: A Simple Model with Gauss Heat Bath
Large entropy fluctuations in a nonequilibrium steady state of classical
mechanics were studied in extensive numerical experiments on a simple 2-freedom
model with the so-called Gauss time-reversible thermostat. The local
fluctuations (on a set of fixed trajectory segments) from the average heat
entropy absorbed in thermostat were found to be non-Gaussian. Approximately,
the fluctuations can be discribed by a two-Gaussian distribution with a
crossover independent of the segment length and the number of trajectories
('particles'). The distribution itself does depend on both, approaching the
single standard Gaussian distribution as any of those parameters increases. The
global time-dependent fluctuations turned out to be qualitatively different in
that they have a strict upper bound much less than the average entropy
production. Thus, unlike the equilibrium steady state, the recovery of the
initial low entropy becomes impossible, after a sufficiently long time, even in
the largest fluctuations. However, preliminary numerical experiments and the
theoretical estimates in the special case of the critical dynamics with
superdiffusion suggest the existence of infinitely many Poincar\'e recurrences
to the initial state and beyond. This is a new interesting phenomenon to be
farther studied together with some other open questions. Relation of this
particular example of nonequilibrium steady state to a long-standing persistent
controversy over statistical 'irreversibility', or the notorious 'time arrow',
is also discussed. In conclusion, an unsolved problem of the origin of the
causality 'principle' is touched upon.Comment: 21 pages, 7 figure
- …