2,899 research outputs found
Efficient computation of hashes
The sequential computation of hashes at the core of many distributed storage systems and found, for example, in grid services can hinder efficiency in service quality and even pose security challenges that can only be addressed by the use of parallel hash tree modes. The main contributions of this paper are, first, the identification of several efficiency and security challenges posed by the use of sequential hash computation based on the Merkle-Damgard engine. In addition, alternatives for the parallel computation of hash trees are discussed, and a prototype for a new parallel implementation of the Keccak function, the SHA-3 winner, is introduced
Topological properties of the bond-modulated honeycomb lattice
We study the combined effects of lattice deformation, e-e interaction and
spin-orbit coupling in a two-dimensional (2D) honeycomb lattice. We adopt
different kinds of hopping modulation--generalized dimerization and a Kekule
distortion--and calculate topological invariants for the non-interacting system
and for the interacting system. We identify the parameter range (Hubbard U,
hopping modulation, spin-orbit coupling) where the 2D system behaves as a
trivial insulator or Quantum Spin Hall Insulator.Comment: 8 pages, 4 figures: discussion improved, typos corrected, references
updated. Matches version published in PR
Topological invariants in interacting Quantum Spin Hall: a Cluster Perturbation Theory approach
Using Cluster Perturbation Theory we calculate Green's functions,
quasi-particle energies and topological invariants for interacting electrons on
a 2-D honeycomb lattice, with intrinsic spin-orbit coupling and on-site e-e
interaction. This allows to define the parameter range (Hubbard U vs spin-orbit
coupling) where the 2D system behaves as a trivial insulator or Quantum Spin
Hall insulator. This behavior is confirmed by the existence of gapless
quasi-particle states in honeycomb ribbons. We have discussed the importance of
the cluster symmetry and the effects of the lack of full translation symmetry
typical of CPT and of most Quantum Cluster approaches. Comments on the limits
of applicability of the method are also provided.Comment: 7 pages, 7 figures: discussion improved, one figure added, references
updated. Matches version published in New J. Phy
Adiabatic Invariants and Scalar Fields in a de Sitter Space-Time
The method of adiabatic invariants for time dependent Hamiltonians is applied
to a massive scalar field in a de Sitter space-time. The scalar field ground
state, its Fock space and coherent states are constructed and related to the
particle states. Diverse quantities of physical interest are illustrated, such
as particle creation and the way a classical probability distribution emerges
for the system at late times.Comment: 9 pages, Latex, no figure
Glutathione-loaded solid lipid microparticles as innovative delivery system for oral antioxidant therapy
The present study aimed to develop a novel formulation containing glutathione (GSH) as an oral antioxidant therapy for the treatment of oxidative stress-related intestinal diseases. To this purpose, solid lipid microparticles (SLMs) with Dynasan 114 and a mixture of Dynasan 114 and Dynasan 118 were produced by spray congealing technology. The obtained SLMs had main particle sizes ranging from 250 to 355 µm, suitable for oral administration. GSH was efficiently loaded into the SLMs at 5% or 20% w/w and the encapsulation process did not modify its chemico-physical properties, as demonstrated by FT-IR, DSC and HSM analysis. Moreover, in vitro release studies using biorelevant media showed that Dynasan 114-based SLMs could efficiently release GSH in various intestinal fluids, while 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay demonstrated the good radical scavenging activity of this formulation. Dynasan 114-based SLMs exhibited an excellent biocompatibility on intestinal HT-29 cells at concentrations up to 2000 µg/mL. SLMs containing GSH alone or together with another antioxidant agent (catalase) were effective in reducing intracellular reactive oxygen species (ROS) levels. Overall, this study indicated that spray congealed SLMs are a promising oral drug delivery system for the encapsulation of one or more biological antioxidant agents for local intestinal treatment
Is there a role for dual PI3K/mTOR inhibitors for patients affected with lymphoma?
The activation of the PI3K/AKT/mTOR pathway is a main driver of cell growth, proliferation, survival, and chemoresistance of cancer cells, and, for this reason, represents an attractive target for developing targeted anti-cancer drugs. There are plenty of preclinical data sustaining the anti-tumor activity of dual PI3K/mTOR inhibitors as single agents and in combination in lymphomas. Clinical responses, including complete remissions (especially in follicular lymphoma patients), are also observed in the very few clinical studies performed in patients that are affected by relapsed/refractory lymphomas or chronic lymphocytic leukemia. In this review, we summarize the literature on dual PI3K/mTOR inhibitors focusing on the lymphoma setting, presenting both the three compounds still in clinical development and those with a clinical program stopped or put on hold
SHARE Working Paper Series 61-2021: How did European retirees respond to the COVID-19 pandemic?
From Quantum Query Complexity to State Complexity
State complexity of quantum finite automata is one of the interesting topics
in studying the power of quantum finite automata. It is therefore of importance
to develop general methods how to show state succinctness results for quantum
finite automata. One such method is presented and demonstrated in this paper.
In particular, we show that state succinctness results can be derived out of
query complexity results.Comment: Some typos in references were fixed. To appear in Gruska Festschrift
(2014). Comments are welcome. arXiv admin note: substantial text overlap with
arXiv:1402.7254, arXiv:1309.773
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