10,097 research outputs found
The Effects of Minimal Length, Maximal Momentum and Minimal Momentum in Entropic Force
In this paper, the modified entropic force law is studied by using a new kind
of generalized uncertainty principle which contains a minimal length, a minimal
momentum and a maximal momentum. Firstly, the quantum corrections to the
thermodynamics of a black hole is investigated. Then, according to Verlinde's
theory, the generalized uncertainty principle (GUP) corrected entropic force is
obtained. The result shows that the GUP corrected entropic force is related not
only to the properties of the black holes, but also to the Planck length and
the dimensionless constants and . Moreover,
based on the GUP corrected entropic force, we also derive the modified
Einstein's field equation (EFE) and the modified Friedmann equation.Comment: 16 pages. arXiv admin note: substantial text overlap with
arXiv:1604.0470
Functional exploration of co-expression networks identifies a nexus for modulating protein and citric acid titres in Aspergillus niger submerged culture
Background: Filamentous fungal cell factories are used to produce numerous proteins, enzymes, and organic acids. Protein secretion and filamentous growth are tightly coupled at the hyphal tip. Additionally, both these processes require ATP and amino acid precursors derived from the citric acid cycle. Despite this interconnection of organic acid production and protein secretion/filamentous growth, few studies in fungi have identified genes which may concomitantly impact all three processes.
Results: We applied a novel screen of a global co-expression network in the cell factory Aspergillus niger to identify candidate genes which may concomitantly impact macromorphology, and protein/organic acid fermentation. This identified genes predicted to encode the Golgi localized ArfA GTPase activating protein (GAP, AgeB), and ArfA guanine nucleotide exchange factors (GEFs SecG and GeaB) to be co-expressed with citric acid cycle genes. Consequently, we used CRISPR-based genome editing to place the titratable Tet-on expression system upstream of ageB, secG, and geaB in A. niger. Functional analysis revealed that ageB and geaB are essential whereas secG was dispensable for early filamentous growth. Next, gene expression was titrated during submerged cultivations under conditions for either protein or organic acid production. ArfA regulators played varied and culture-dependent roles on pellet formation. Notably, ageB or geaB expression levels had major impacts on protein secretion, whereas secG was dispensable. In contrast, reduced expression of each predicted ArfA regulator resulted in an absence of citric acid in growth media. Finally, titrated expression of either GEFs resulted in an increase in oxaloacetic acid concentrations in supernatants.
Conclusion: Our data suggest that the Golgi may play an underappreciated role in modulating organic acid titres during industrial applications, and that this is SecG, GeaB and AgeB dependent in A. niger. These data may lead to novel avenues for strain optimization in filamentous fungi for improved protein and organic acid titres.TU Berlin, Open-Access-Mittel - 201
Investigating the NCQ scaling of elliptic flow at LHC with a multiphase transport model
The number of constituent quark (NCQ) scaling behavior of elliptic flow has
been systematically studied at the LHC energy within the framework of a
multiphase transport model (AMPT) in this work. We find that the parameters
used to generate the initial states and the collision centrality are important
for the existence of NCQ scaling even when hadronic rescattering contribution
is off in Pb-Pb collisions of TeV. By turning on the
hadron rescattering process, the hadronic evolution impacts are also found to
be significant. Extending the analysis to Pb-Pb collsions of
TeV, one would observe similar qualitative features
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