University of Patras

About: University of Patras is a education organization based out in Pátrai, Greece. It is known for research contribution in the topics: Population & Catalysis. The organization has 13372 authors who have published 31263 publications receiving 677159 citations. The organization is also known as: Panepistímio Patrón.

Insight on the Formation of Chitosan Nanoparticles through Ionotropic Gelation with Tripolyphosphate

Abstract: This work reports details pertaining to the formation of chitosan nanoparticles that we prepare by the ionic gelation method. The molecular interactions of the ionic cross-linking of chitosan with tripolyphosphate have been investigated and elucidated by means of all-electron density functional theory. Solvent effects have been taken into account using implicit models. We have identified primary-interaction ionic cross-linking configurations that we define as H-link, T-link, and M-link, and we have quantified the corresponding interaction energies. H-links, which display high interaction energies and are also spatially broadly accessible, are the most probable cross-linking configurations. At close range, proton transfer has been identified, with maximum interaction energies ranging from 12.3 up to 68.3 kcal/mol depending on the protonation of the tripolyphosphate polyanion and the relative coordination of chitosan with tripolyphosphate. On the basis of our results for the linking types (interaction energ...

Editorial: Nicotine and SARS-CoV-2: COVID-19 may be a disease of the nicotinic cholinergic system.

Abstract: As of 20 April, almost 1.7 million people globally have been diagnosed with Corona Virus Disease 2019 (COVID-19), a pandemic that has evolved from the emergence of a new coronavirus strain, acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in China. More than 170,000 deaths have been reported, while there are certainly many more cases of milder disease that have not been diagnosed and officially confirmed due to limited testing capacity in most countries. The pandemic is a global emergency due to the rapid transmission of the disease and the potential to overwhelm the healthcare systems, and is expected to have considerable economic and health impacts. Contributing factors and their possible role in the relatively high infection, death rates between countries and origin have recently been studied [1,2]. This new outbreak has been additionally evaluated for current knowledge on coronaviruses based on a short history to epidemiology, pathogenesis, clinical manifestation of the disease, as well as treatment and prevention strategies [3]. The search for potential protective and therapeutic antiviral strategies is of particular and urgent concern [4]. While in most cases, especially in young people without any comorbidities, the disease is expected to be relatively mild, there is a substantial proportion of patients who develop complications and need intensive care-unit support and mechanical ventilation. In one case series of 1099 patients in China [5], 6.1 % of cases suffered from the primary composite end-point of admission to an intensive care unit, use of mechanical ventilation, or death. Patients with severe disease typically present with dyspnea and hypoxemia shortly after disease initiation, and may quickly progress to respiratory failure, acute respiratory distress syndrome (ARDS) and multi-organ failure [6]. Predictors of adverse outcomes include elevated levels of inflammatory markers and pro-inflammatory cytokines. A study of 150 COVID-19 cases reported that elevated levels of C-reactive protein (CRP), ferritin and IL-6 were associated with death [7]. IL-6, an important pro-inflammatory cytokine, was elevated in fatal cases of COVID-19 in another study of 191 patients [8]. Another study of 452 patients reported that those with severe disease showed lymphocytopenia, neutrophilia, low levels of monocytes, eosinophils and basophils, and elevated levels of infection-related biomarkers and inflammatory cytokines [9]. Pathological examination of a case in China revealed bilateral diffuse alveolar damage, desquamation of pneumocytes, hyaline membrane formation and interstitial mononuclear inflammatory infiltrates [10]. Flow cytometry of peripheral blood revealed reduced levels of CD4+ and CD8 + T cells, which however were hyper-activated, and elevated concentration of pro-inflammatory CCR6+ Th17 in CD4 + T cells. Such findings are hallmarks of ARDS and resemble features observed in SARS and Middle Eastern Respiratory Syndrome [11,12]. Systemic vasculitis was also observed [10]. Therefore, it seems that immune dysregulation may be implicated in the pathophysiology of severe COVID-19.

Fuzzy Cognitive Maps: Basic Theories and Their Application to Complex Systems

Abstract: The challenging problem of modeling and controlling complex systems is investigated using Fuzzy Cognitive Maps (FCMs). A mathematical description of FCM models is presented, new construction methods and an algorithm are developed and extensively examined. The issue of modeling the supervisor of large complex systems is addressed and is modeled using a FCM. A manufacturing example is used to prove the usefulness of the proposed method. The problem of Decision Making process in Decision Analysis is considered and analyzed using FCM models. A successful application of FCM theory in a health problem is provided.

Tension and constraints on modified gravity parametrizations of $G_{\textrm{eff}}(z)$ from growth rate and Planck data

Abstract: We construct an updated and extended compilation of growth-rate data based on recent redshift-space distortion measurements. The data set consists of 34 data points and includes corrections for model dependence. In order to minimize overlap and maximize the independence of the data points, we also construct a subsample of this compilation (a ``gold'' growth data set) which consists of 18 data points. We test the consistency of this data set with the best-fit $\mathrm{Planck}15/\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ parameters in the context of General Relativity using the evolution equation for the growth factor $\ensuremath{\delta}(a)$ with a $w\mathrm{CDM}$ background. We find tension at the $\ensuremath{\sim}3\ensuremath{\sigma}$ level between the best-fit parameters $w$ (the dark energy equation of state), ${\mathrm{\ensuremath{\Omega}}}_{0m}$ (the matter density parameter), and ${\ensuremath{\sigma}}_{8}$ (the matter power spectrum normalization on scales $8{h}^{\ensuremath{-}1}\text{ }\text{ }\mathrm{Mpc}$) and the corresponding $\mathrm{Planck}15/\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ parameters ($w=\ensuremath{-}1$, ${\mathrm{\ensuremath{\Omega}}}_{0m}=0.315$, and ${\ensuremath{\sigma}}_{8}=0.831$). We show that the tension disappears if we allow for evolution of the effective Newton constant, parametrized as ${G}_{\mathrm{eff}}(a)/{G}_{\mathrm{N}}=1+{g}_{a}(1\ensuremath{-}a{)}^{n}\ensuremath{-}{g}_{a}(1\ensuremath{-}a{)}^{2n}$ with $n\ensuremath{\ge}2$ where ${g}_{a}$ and $n$ are parameters of the model, $a$ is the scale factor, and $z=1/a\ensuremath{-}1$ is the redshift. This parametrization satisfies three important criteria: a) positive energy of the graviton (${G}_{\mathrm{eff}}g0$), b) consistency with big bang nucleosynthesis constraints (${G}_{\mathrm{eff}}(a\ensuremath{\ll}1)/{G}_{\mathrm{N}}=1$), and c) consistency with Solar System tests (${G}_{\mathrm{eff}}(a=1)/{G}_{\mathrm{N}}=1$ and ${G}_{\mathrm{eff}}^{\ensuremath{'}}(a=1)/{G}_{\mathrm{N}}=0$). We show that the best-fit form of ${G}_{\mathrm{eff}}(z)$ obtained from the growth data corresponds to weakening gravity at recent redshifts (decreasing function of $z$), and we demonstrate that this behavior is not consistent with any scalar-tensor Lagrangian with a real scalar field. Finally, we use MGCAMB to find the best-fit ${G}_{\mathrm{eff}}(z)$ obtained from the Planck cosmic microwave background power spectrum on large angular scales and show that it is a mildly increasing function of $z$, in $3\ensuremath{\sigma}$ tension with the corresponding decreasing best-fit ${G}_{\mathrm{eff}}(z)$ obtained from the growth data.

Vitamin E for prophylaxis against chemotherapy-induced neuropathy: A randomized controlled trial

Abstract: Background: The authors conducted a pilot, randomized, open label with blind assessment, controlled trial to determine whether vitamin E supplementation has a neuroprotective effect in chemotherapy-induced peripheral nerve damage. Methods: Thirty-one patients with cancer treated with six courses of cumulative cisplatin, paclitaxel, or their combination regimens were randomly assigned in two groups and followed by neurologic examination and electrophysiologic study. Patients assigned in Group I (n = 16) received oral vitamin E at a daily dose of 600 mg/day during chemotherapy and 3 months after its cessation were compared to patients of Group II (n = 15), who received no supplementation and served as controls. The severity of neurotoxicity was summarized by means of a modified peripheral neuropathy score. Results: The incidence of neurotoxicity differed between the two groups, occurring in 4/16 (25%) patients assigned in the vitamin E supplementation group and in 11/15 (73.3%) patients assigned in the control group ( p = 0.019). Mean peripheral neuropathy scores were 3.4 ± 6.3 for patients of Group I and 11.5 ± 10.6 for patients of Group II ( p = 0.026). The relative risk (RR) of developing neurotoxicity was significantly higher in case of control patients, RR = 0.34, 95% CI = 0.14 to 0.84. Conclusion: Vitamin E supplementation in cancer patients may have an important neuroprotective effect.