1,216 research outputs found

    Efficient computation of hashes

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    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

    Glutathione-loaded solid lipid microparticles as innovative delivery system for oral antioxidant therapy

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    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

    General Relativity as Classical Limit of Evolutionary Quantum Gravity

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    We analyze the dynamics of the gravitational field when the covariance is restricted to a synchronous gauge. In the spirit of the Noether theorem, we determine the conservation law associated to the Lagrangian invariance and we outline that a non-vanishing behavior of the Hamiltonian comes out. We then interpret such resulting non-zero ``energy'' of the gravitational field in terms of a dust fluid. This new matter contribution is co-moving to the slicing and it accounts for the ``materialization'' of a synchronous reference from the corresponding gauge condition. Further, we analyze the quantum dynamics of a generic inhomogeneous Universe as described by this evolutionary scheme, asymptotically to the singularity. We show how the phenomenology of such a model overlaps the corresponding Wheeler-DeWitt picture. Finally, we study the possibility of a Schr\"odinger dynamics of the gravitational field as a consequence of the correspondence inferred between the ensemble dynamics of stochastic systems and the WKB limit of their quantum evolution. We demonstrate that the time dependence of the ensemble distribution is associated with the first order correction in \hbar to the WKB expansion of the energy spectrum.Comment: 23 pages, to appear on Class. Quant. Gra

    The interpretation of the solutions of the Wheeler De Witt equation

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    We extract transition amplitudes among matter constituents of the universe from the solutions of the Wheeler De Witt equation. The physical interpretation of these solutions is then reached by an analysis of the properties of the transition amplitudes. The interpretation so obtained is based on the current carried by these solutions and confirms ideas put forward by Vilenkin.Comment: 11 pages, latex, no figure

    Green manure and long-term fertilization effects on available soil zinc and cadmium and their accumulation by wheat (Triticum aestivum L.)

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    Zinc (Zn) deficiency in humans due to imbalanced diets is a global nutritional problem. It is especially widespread in populations of low-income countries depending on cereals as staple food. Grain Zn concentrations are particularly low in cereals grown on soils with low phytoavailable Zn concentrations. . Plant Zn uptake depends on soil properties such as pH, calcium carbonate, iron and manganese oxides, total Zn and organic matter content (OM). Soil pH, total Zn and OM can be influenced on farms with limited access to mineral fertilizers through organic matter management practises. In this study, we investigated to what extent green manure application could increase soil Zn availability and wheat grain Zn concentrations (biofortification) on soil with different long-term fertilizer management

    Cognitive reserve index and functional and cognitive outcomes in severe acquired brain injury: A pilot study

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    Background: Many variables affect outcome after brain injury. Cognitive reserve (CR) is a subjective factor that reflects a set of personal characteristics and that differentiates individuals. It may influence an individual’s capacity to react to brain injury. Objective: To study the effects of cognitive reserve on functional and cognitive outcome at the end of rehabilitation, in patients with severe acquired brain injury (sABI), by means of the Cognitive Reserve Index questionnaire (CRIq). Methods: We report a retrospective study of a continuous series of sABI patients on first admission to a rehabilitation center. Disability and cognitive outcomes were recorded. Results: In the 94 patients enrolled, the assessments after rehabilitation showed a significant gain measured with the disability Rating Scale for patients with a higher CR (CRIq≥ 85). A significant negative correlation was found: between CRIq scores and the interval elapsing before first access to neuropsychological assessment, between CRIq scores, especially level of education, and tests that measure the same domain (attention). Conclusions: Improvements in overall and cognitive disability emerged, but CR did not seem to substantially influence outcome in this sample of patients. This result may be partly due to the clinical severity of the population studied and the sample’s dimension, although quantitatively representative of the population

    Unraveling the mechanism of the one-pot synthesis of exchange coupled Co-based nano-heterostructures with a high energy product

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    The development of reproducible protocols to synthesize hard/soft nano-heterostructures (NHSs) with tailored magnetic properties is a crucial step to define their potential application in a variety of technological areas. Thermal decomposition has proved to be an effective tool to prepare such systems, but it has been scarcely used so far for the synthesis of Co-based metal/ferrite NHSs, despite their intriguing physical properties. We found a new approach to prepare this kind of nanomaterial based on a simple one-pot thermal decomposition reaction of metal-oleate precursors in the high boiling solvent docosane. The obtained NHSs are characterized by the coexistence of Co metal and Co doped magnetite and are highly stable in an air atmosphere, thanks to the passivation of the metal with a very thin oxide layer. The investigation of the influence of the metal precursor composition (a mixed iron-cobalt oleate), of the ligands (oleic acid and sodium oleate) and of the reaction time on the chemical and structural characteristics of the final product, allowed us to rationalize the reaction pathway and to determine the role of each parameter. In particular, the use of sodium oleate is crucial to obtain a metal phase in the NHSs. In such a way, the one-pot approach proposed here allows the fine control of the synthesis, leading to the formation of stable, high performant, metal/ferrite NHSs with tailored magnetic properties. For instance, the room temperature maximum energy product was increased up to 19 kJ m-3 by tuning the Co content in the metal precursor

    Immune-related adverse events in the treatment of non-Hodgkin lymphoma with immune checkpoint inhibitors

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    Immune checkpoint inhibitors (ICIs) show efficacy in the treatment of non-Hodgkin lymphomas (NHL). However, these agents are associated with a unique group of side effects called immune-related adverse events (irAEs). We conducted an observational retrospective/prospective study on patients with relapsed/refractory NHL treated with ICI to determine the incidence of irAEs assessing the type, severity, and timing of onset, outcome and relationship with study drugs of these events. Thirty-two patients underwent ICI as single agent (N = 20) or in combination (N = 12). Ten patients (31.3%) developed at least one irAE for a total of 17 irAEs. Median time to presentation of irAEs was 69 days (range 0–407) with a median resolution time of 16 days (range 0–98). Progression free survival at 24 months for patients who developed an irAE was 40% and 31.8% for who did not. Overall survival for the two groups did not differ (at 24 months 40.0% and 62.5% for patients without and with irAE, respectively), but the median for who developed an irAE was not reached. The incidence of irAEs was associated with better long-term survival in NHL treated with ICIs but patients’ disease conditions need to be carefully evaluated to decide the optimal management

    Processing Succinct Matrices and Vectors

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    We study the complexity of algorithmic problems for matrices that are represented by multi-terminal decision diagrams (MTDD). These are a variant of ordered decision diagrams, where the terminal nodes are labeled with arbitrary elements of a semiring (instead of 0 and 1). A simple example shows that the product of two MTDD-represented matrices cannot be represented by an MTDD of polynomial size. To overcome this deficiency, we extended MTDDs to MTDD_+ by allowing componentwise symbolic addition of variables (of the same dimension) in rules. It is shown that accessing an entry, equality checking, matrix multiplication, and other basic matrix operations can be solved in polynomial time for MTDD_+-represented matrices. On the other hand, testing whether the determinant of a MTDD-represented matrix vanishes PSPACE$-complete, and the same problem is NP-complete for MTDD_+-represented diagonal matrices. Computing a specific entry in a product of MTDD-represented matrices is #P-complete.Comment: An extended abstract of this paper will appear in the Proceedings of CSR 201
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