1,623 research outputs found
Weighted Multiplex Networks
One of the most important challenges in network science is to quantify the
information encoded in complex network structures. Disentangling randomness
from organizational principles is even more demanding when networks have a
multiplex nature. Multiplex networks are multilayer systems of nodes that
can be linked in multiple interacting and co-evolving layers. In these
networks, relevant information might not be captured if the single layers were
analyzed separately. Here we demonstrate that such partial analysis of layers
fails to capture significant correlations between weights and topology of
complex multiplex networks. To this end, we study two weighted multiplex
co-authorship and citation networks involving the authors included in the
American Physical Society. We show that in these networks weights are strongly
correlated with multiplex structure, and provide empirical evidence in favor of
the advantage of studying weighted measures of multiplex networks, such as
multistrength and the inverse multiparticipation ratio. Finally, we introduce a
theoretical framework based on the entropy of multiplex ensembles to quantify
the information stored in multiplex networks that would remain undetected if
the single layers were analyzed in isolation.Comment: (22 pages, 10 figures
Analytic treatment of the thermoelectric properties for two coupled quantum dots threaded by magnetic fields
Coupled double quantum dots (c-2QD) connected to leads have been widely adopted as prototype
model systems to verify interference effects on quantum transport at the nanoscale.Weprovide here
an analytic study of the thermoelectric properties of c-2QD systems pierced by a uniform magnetic
field. Fully analytic and easy-to-use expressions are derived for all the kinetic functionals of interest.
Within the Green’s function formalism, our results allow a simple inexpensive procedure for the
theoretical description of the thermoelectric phenomena for different chemical potentials and
temperatures of the reservoirs, different threading magnetic fluxes, dot energies and interdot
interactions; moreover they provide an intuitive guide to parametrize the system Hamiltonian for the
design of best performing realistic devices.Wehave found that the thermopower S can be enhanced by
more than ten times and the figure of merit ZT by more than hundred times by the presence of a
threading magnetic field. Most important, we show that the magnetic flux increases also the
performance of the device under maximum power output conditions
Network Entropy measures applied to different systemic perturbations of cell basal state
NOTE: includes supplementary materialNOTE: includes supplementary materialNOTE: includes supplementary materialWe characterize different cell states, related to cancer and ageing phenotypes, by a measure of entropy of network ensembles, integrating gene expression values and protein interaction networks. The entropy measure estimates the parameter space available to the network ensemble, that can be interpreted as the level of plasticity of the system for high entropy values (the ability to change its internal parameters, e.g. in response to environmental stimuli), or as a fine tuning of the parameters (that restricts the range of possible parameter values) in the opposite case. This approach can be applied at different scales, from whole cell to single biological functions, by defining appropriate subnetworks based on a priori biological knowledge, thus allowing a deeper understanding of the cell processes involved. In our analysis we used specific network features (degree sequence, subnetwork structure and distance between gene profiles) to obtain informations at different biological scales, providing a novel point of view for the integration of experimental transcriptomic data and a priori biological knowledge, but the entropy measure can also highlight other aspects of the biological systems studied depending on the constraints introduced in the model (e.g. community structures)
Thermoelectric efficiency of nanoscale devices in the linear regime
We study quantum transport through two-terminal nanoscale devices in contact with two particle reservoirs at different temperatures and chemical potentials. We discuss the general expressions controlling the electric charge current, heat currents, and the efficiency of energy transmutation in steady conditions in the linear regime. With focus in the parameter domain where the electron system acts as a power generator, we elaborate workable expressions for optimal efficiency and thermoelectric parameters of nanoscale devices. The general concepts are set at work in the paradigmatic cases of Lorentzian resonances and antiresonances, and the encompassing Fano transmission function: the treatments are fully analytic, in terms of the trigamma functions and Bernoulli numbers. From the general curves here reported describing transport through the above model transmission functions, useful guidelines for optimal efficiency and thermopower can be inferred for engineering nanoscale devices in energy regions where they show similar transmission functions
Meropenem-Vaborbactam as Salvage Therapy for Ceftazidime-Avibactam-, Cefiderocol-Resistant ST-512 Klebsiella pneumoniae-Producing KPC-31, a D179Y Variant of KPC-3
A 68-year-old man had recurrent bacteremia by Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae resistant to ceftazidime-avibactam and cefiderocol. The sequencing of a target region showed that it harbored a KPC-3 variant enzyme (D179Y; KPC-31), which confers resistance to ceftazidime-avibactam and restores meropenem susceptibility. The patient was successfully treated with meropenem-vaborbactam
Quercetin loaded gelatin films with modulated release and tailored anti-oxidant, mechanical and swelling properties
Quercetin, a flavonoid widely diffused in fruits and vegetables, is known for its good pharmacological qualities, such as anti-oxidant and anti-inflammatory properties. In this work, we loaded quercetin on gelatin films with the aim to develop materials with tailored anti-oxidant, mechanical and stability properties. To this purpose, gelatin films at increasing flavonoid content were prepared using two different solvents, namely H2O/EtOH (EtOH films) and DMSO (DMSO films). Quercetin content increased up to about 3.8 and 1.8 wt% in DMSO and EtOH films, respectively. The use of DMSO as solvent prevents the partial regain of collagen triple helix structure during gelling of gelatin sols and results in remarkable extensibility of the films. At variance, EtOH films display X-ray diffraction patterns and DSC plots in agreement with the presence of triple helix structure, and exhibit reduced swelling and increasing mechanical properties on increasing quercetin content. Moreover, their values of denaturation enthalpy indicate the presence of chemical interaction between the flavonoid and gelatin, which can be responsible of their lower quercetin release in PBS in comparison to DMSO films. The flavonoid release is sustained for both series of films and occurs through anchorage to gelatin nanoparticles. Moreover, both DMSO and EtOH functionalized films exhibit relevant anti-oxidant properties, in agreement with their RSA levels, which are comparable to that of pure quercetin
Alternating block copolymer-based nanoparticles as tools to modulate the loading of multiple chemotherapeutics and imaging probes
Abstract Cancer therapy often relies on the combined action of different molecules to overcome drug resistance and enhance patient outcome. Combined strategies relying on molecules with different pharmacokinetics often fail due to the lack of concomitant tumor accumulation and, thus, to the loss of synergistic effect. Due to their ability to enhance treatment efficiency, improve drug pharmacokinetics, and reduce adverse effects, polymer nanoparticles (PNPs) have been widely investigated as co-delivery vehicles for cancer therapies. However, co-encapsulation of different drugs and probes in PNPs requires a flexible polymer platform and a tailored particle design, in which both the bulk and surface properties of the carriers are carefully controlled. In this work, we propose a core-shell PNP design based on a polyurethane (PUR) core and a phospholipid external surface. The modulation of the hydrophilic/hydrophobic balance of the PUR core enhanced the encapsulation of two chemotherapeutics with dramatically different water solubility (Doxorubicin hydrochloride, DOXO and Docetaxel, DCTXL) and of Iron Oxide Nanoparticles for MRI imaging. The outer shell remained unchanged among the platforms, resulting in un-modified cellular uptake and in vivo biodistribution. We demonstrate that the choice of PUR core allowed a high entrapment efficiency of all drugs, superior or comparable to previously reported results, and that higher core hydrophilicity enhances the loading efficiency of the hydrophilic DOXO and the MRI contrast effect. Moreover, we show that changing the PUR core did not alter the surface properties of the carriers, since all particles showed a similar behavior in terms of cell internalization and in vivo biodistribution. We also show that PUR PNPs have high passive tumor accumulation and that they can efficient co-deliver the two drugs to the tumor, reaching an 11-fold higher DOXO/DCTXL ratio in tumor as compared to free drugs. Statement of Significance Exploiting the synergistic action of multiple chemotherapeutics is a promising strategy to improve the outcome of cancer patients, as different agents can simultaneously engage different features of tumor cells and/or their microenvironment. Unfortunately, the choice is limited to drugs with similar pharmacokinetics that can concomitantly accumulate in tumors. To expand the spectrum of agents that can be delivered in combination, we propose a multi-compartmental core-shell nanoparticles approach, in which the core is made of biomaterials with high affinity for drugs of different physical properties. We successfully co-encapsulated Doxorubicin Hydrochloride, Docetaxel, and contrast agents and achieved a significantly higher concomitant accumulation in tumor versus free drugs, demonstrating that nanoparticles can improve synergistic cancer chemotherapy
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