42 research outputs found
Performance Limits of Spatially Distributed Molecular Communications With Receiver Saturation
Molecular via diffusion are affected by unreliability and inter symbol interference in case of single transmitter. A promising solution to these issues appears to be the adoption of a swarm of randomly distributed transmitting nano-devices and a single spherical receiver. However, such a perspective assumes the receiver as fully absorbing (i.e., able to absorb an unlimited number of molecules per second). In this letter, we show that, if this assumption is relaxed, increasing the number of point transmitters leads to a saturation effect which makes communication impossible when digital transmission is considered. By means of a first and second order spatio-temporal stochastic model, we analytically derive the maximum allowed point transmitters density before saturation arises, as a function of parameters such as the diffusion coefficient, the maximum number of absorbed molecules, and the number of previously transmitted symbols. The analysis is validated via Monte Carlo simulation
Flavonoids in Lemon and Grapefruit IntegroPectin**
Following the analysis of terpenes present in new lemon and grapefruit “IntegroPectin” pectins obtained via the hydrodynamic cavitation of industrial lemon and grapefruit processing waste, the HPLC-MS analysis of flavonoid and other phenolic compounds reveals the presence of eriocitrin, naringin, hesperidin and kaempferol typical of the respective citrus fruits. The pectic fibers rich in rhamnogalacturonan-I regions act as chemical sponges adsorbing and concentrating at their outer surface highly bioactive citrus flavonoids and terpenes. These findings, together with the unique molecular structure of these new whole citrus pectins, provide preliminary insight into the broad-scope biological activity of these new biomaterials. Numerous new biomedical applications are anticipated, including likely use in the prevention and treatment of microbial infections and neurodegenerative disease
Antioxidant phytocomplexes extracted from pomegranate (Punica granatum L.) using hydrodynamic cavitation show potential anticancer activity in vitro
Hydrodynamic cavitation (HC), as an effective, efficient, and scalable extraction technique for natural products, could enable the affordable production of valuable antioxidant extracts from plant resources. For the first time, whole pomegranate (Punica granatum L.) fruits, rich in bioactive phytochemicals endowed with anti-cancer properties, were extracted in water using HC. Aqueous fractions sequentially collected during the process (M1–M5) were lyophilized (L), filtered (A), or used as such, i.e., crude (C), and analyzed for their biochemical profile and in vitro antioxidant power. The fractions M3 and M4 from the L and C series showed the highest antiradical activity and phytochemical content. While the lyophilized form is preferable for application purposes, sample L-M3, which was produced faster and with lower energy consumption than M4, was used to assess the potential antiproliferative effect on human breast cancer line (AU565-PAR) and peripheral blood mononuclear (PBMC) cells from healthy donors. In a pilot study, cell growth, death, and redox state were assessed, showing that L-M3 significantly reduced tumor cell proliferation and intracellular oxygen reactive species. No effect on PBMCs was detected. Thus, the antioxidant phytocomplex extracted from pomegranate quickly (15 min), at room temperature (30 °C), and efficiently showed potential anticancer activity without harming healthy cells
Electronic properties of electron-deficient Zn(II) porphyrins for HBr splitting
Two different high potential Zn(II) porphyrin designs carrying either 4 or 5 meso pentafluorophenyl moieties as electron acceptor groups and a further electron withdrawing branch inserted in either the \u3b2 (1) or meso (2) position were tested in photoelectrosynthetic cells for HBr splitting. Photoaction spectra in the presence of HBr showed that red photons up to 700 nm could be harvested and converted and that 2 performed better than 1, thanks to better electronic properties of the excited state, favored by the insertion of the benzothiadiazole electron withdrawing group. Photoanodic performances in the presence of HBr, however, remained low, due to inefficient regeneration of the oxidized sensitizer as a result of an insufficient driving force for Br- oxidation
Double-Stranded RNA Attenuates the Barrier Function of Human Pulmonary Artery Endothelial Cells
Circulating RNA may result from excessive cell damage or acute viral infection and can interact with vascular endothelial cells. Despite the obvious clinical implications associated with the presence of circulating RNA, its pathological effects on endothelial cells and the governing molecular mechanisms are still not fully elucidated. We analyzed the effects of double stranded RNA on primary human pulmonary artery endothelial cells (hPAECs). The effect of natural and synthetic double-stranded RNA (dsRNA) on hPAECs was investigated using trans-endothelial electric resistance, molecule trafficking, calcium (Ca2+) homeostasis, gene expression and proliferation studies. Furthermore, the morphology and mechanical changes of the cells caused by synthetic dsRNA was followed by in-situ atomic force microscopy, by vascular-endothelial cadherin and F-actin staining. Our results indicated that exposure of hPAECs to synthetic dsRNA led to functional deficits. This was reflected by morphological and mechanical changes and an increase in the permeability of the endothelial monolayer. hPAECs treated with synthetic dsRNA accumulated in the G1 phase of the cell cycle. Additionally, the proliferation rate of the cells in the presence of synthetic dsRNA was significantly decreased. Furthermore, we found that natural and synthetic dsRNA modulated Ca2+ signaling in hPAECs by inhibiting the sarco-endoplasmic Ca2+-ATPase (SERCA) which is involved in the regulation of the intracellular Ca2+ homeostasis and thus cell growth. Even upon synthetic dsRNA stimulation silencing of SERCA3 preserved the endothelial monolayer integrity. Our data identify novel mechanisms by which dsRNA can disrupt endothelial barrier function and these may be relevant in inflammatory processes
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
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Early Devonian (Late Emsian) shark fin remains (Chondrichthyes) from the Paraná Basin, southern Brazil
This is an open-access article distributed under the terms of the Creative Commons Attribution License [Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)]. The attached file is the published version of the article
Spatially Distributed Molecular Communications via Diffusion: Second-Order Analysis
Unlike electromagnetic communications, where the noise is typically represented by a (Gaussian) independent source which is added to the useful signal (additive noise), molecular communications via diffusion are affected by a random disturbance which is intrinsically related to the random nature of emission, propagation (Brownian motion) and reception. In point-to-point molecular communications, the number of received molecules is generally a Poisson random variable. Thus, the evaluation of the signal-to-noise ratio (intended as the ratio between the squared mean value of the received molecules and its variance) is not a problem of interest, since its value simply equals the mean of such a random variable. However, in spatially distributed communications, where the point transmitters are randomly placed in the 3D space according to a point process, the number of received molecules derives from the contribution of a random sum of emissions, so that it is no more a Poisson random variable. Thus, the evaluation of the signal-to-noise ratio is not trivial. Here, we provide an analytical framework to evaluate the signal-to-noise ratio in spatially distributed molecular communications for both synchronous and asynchronous transmitters. The analysis is extended to the signal-to-interference-noise ratio when digital communications with intersymbol interference are considered