Hypoxic Cell Waves around Necrotic Cores in Glioblastoma: A Biomathematical Model and its Therapeutic Implications

Glioblastoma is a rapidly evolving high-grade astrocytoma that is distinguished pathologically from lower grade gliomas by the presence of necrosis and microvascular hiperplasia. Necrotic areas are typically surrounded by hypercellular regions known as "pseudopalisades" originated by local tumor vessel occlusions that induce collective cellular migration events. This leads to the formation of waves of tumor cells actively migrating away from central hypoxia. We present a mathematical model that incorporates the interplay among two tumor cell phenotypes, a necrotic core and the oxygen distribution. Our simulations reveal the formation of a traveling wave of tumor cells that reproduces the observed histologic patterns of pseudopalisades. Additional simulations of the model equations show that preventing the collapse of tumor microvessels leads to slower glioma invasion, a fact that might be exploited for therapeutic purposes.Comment: 29 pages, 9 figure

Laser-induced effects on the electronic features of graphene nanoribbons

We study the interplay between lateral confinement and photon-induced processes on the electronic properties of illuminated graphene nanoribbons. We find that by tuning the device setup (edges geometries, ribbon width and polarization direction), a laser with frequency {\Omega} may either not affect the electronic structure, or induce bandgaps or depletions at \hbar {\Omega}/2, and/or at other energies not commensurate with half the photon energy. Similar features are also observed in the dc conductance, suggesting the use of the polarization direction to switch on and off the graphene device. Our results could guide the design of novel types of optoelectronic nano-devices.Comment: 4 pages, 3 figure

Tuning laser-induced bandgaps in graphene

Could a laser field lead to the much sought-after tunable bandgaps in graphene? By using Floquet theory combined with Green's functions techniques, we predict that a laser field in the mid-infrared range can produce observable bandgaps in the electronic structure of graphene. Furthermore, we show how they can be tuned by using the laser polarization. Our results could serve as a guidance to design opto-electronic nano-devices.Comment: 4 pages, 3 figures, to appear in Applied Physics Letter

Non-perturbative laser effects on the electrical properties of graphene nanoribbons

The use of Floquet theory combined with a realistic description of the electronic structure of illuminated graphene and graphene nanoribbons is developed to assess the emergence of non-adiabatic and non-perturbative effects on the electronic properties. Here, we introduce an efficient computational scheme and illustrate its use by applying it to graphene nanoribbons in the presence of both linear and circular polarization. The interplay between confinement due to the finite sample size and laser-induced transitions is shown to lead to sharp features on the average conductance and density of states. Particular emphasis is given to the emergence of the bulk limit response.Comment: 14 pages, 8 figures, to appear in J. Phys.: Condens. Matter, special issue on "Ultrafast and nonlinear optics in carbon nanomaterials

Combined therapies of antithrombotics and antioxidants delay in silico brain tumor progression

Glioblastoma multiforme, the most frequent type of primary brain tumor, is a rapidly evolving and spatially heterogeneous high-grade astrocytoma that presents areas of necrosis, hypercellularity and microvascular hyperplasia. The aberrant vasculature leads to hypoxic areas and results in an increase of the oxidative stress selecting for more invasive tumor cell phenotypes. In our study we assay in silico different therapeutic approaches which combine antithrombotics, antioxidants and standard radiotherapy. To do so, we have developed a biocomputational model of glioblastoma multiforme that incorporates the spatio-temporal interplay among two glioma cell phenotypes corresponding to oxygenated and hypoxic cells, a necrotic core and the local vasculature whose response evolves with tumor progression. Our numerical simulations predict that suitable combinations of antithrombotics and antioxidants may diminish, in a synergetic way, oxidative stress and the subsequent hypoxic response. This novel therapeutical strategy, with potentially low or no toxicity, might reduce tumor invasion and further sensitize glioblastoma multiforme to conventional radiotherapy or other cytotoxic agents, hopefully increasing median patient overall survival time.Comment: 8 figure

Combustion of avocado crop residues: effect of crop variety and nature of nutrients

The thermal behaviour of avocado crop residues was studied. The seeds and the pruning remains from Hass and Bacon varieties were analysed to know their fuel properties. The influence of the fertiliser nature was also studied thorough the application of cow manure and inorganic products. Thermogravimetric analysis (TGA) was carried out under 10, 20 and 40 °C/min heating rates. Kinetics was also estimated according to the Friedman, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. Results indicated the good fuel performance of the samples. Higher heating values (HHV) were higher for pruning remains (19.43 MJ/kg) when compared to seeds (18.74 MJ/kg). Cow manure improved the behaviour of all avocado samples regardless of the varieties. Average action energy was lower for wood (143.89–211.04 kJ/mol) than seeds (174.05–279.99 kJ/mol). Regarding TGA, this analysis showed three different mass loss associated to hemicellulose, cellulose and lignin release. TGA profiles were so different for the analysed biomass sources according to the fertiliser employed. Hence, the heating rate influenced the thermal behaviour of the samples, highlighting the fast release of the SBC and WHM for the 10 and 20 °C/min ramps respectively

Zoonosis. The Hidden Face of the COVID-19 Pandemic

Zoonoses are diseases that are transmitted naturally between animals and man. Their interest is enormous and growing, especially in recent years in which they have emerged as serious and widespread problems, such as emerging zoonoses. Zoonoses represent at least 60% of human infectious diseases and up to 75% of emerging diseases, so their relative importance is more than justified. From the health point of view they are the cause of death, disease, suffering and sequelae, and from the economic point of view, they cause damage in nations or throughout the world, when the spread of the disease is global. The article discusses issues related to the prediction, prevention and control of zoonoses and is particularly set, due to its timeliness, in COVID-19, a pandemic that has the status of zoonosis by admitting its origin in bats. The union of forces between animal health, human health and environmental health, in the context of One Health, is important to achieve success in the control and eradication of these diseases.Las zoonosis son enfermedades que se transmiten de forma natural entre los animales y el hombre. Su interés es enorme y creciente, especialmente en los últimos años en los que han emergido como problemas de gravedad y gran difusión, como zoonosis emergentes. Las zoonosis representan, al menos, el 60% de las enfermedades infecciosas humanas y hasta el 75% de las enfermedades emergentes, por lo que su importancia relativa esta sobradamente justificada. Desde el punto de vista sanitario son causa de muerte, enfermedad, sufrimiento y secuelas y, desde el punto de vista económico, causan quebranto en las naciones o, en todo el mundo, cuando la extensión de la enfermedad es global. El artículo discute cuestiones relativas a la predicción, prevención y control de zoonosis y se fija de modo particular, por su actualidad, en la COVID-19, una pandemia que tiene la condición de zoonosis al admitirse su origen en murciélagos con la intervención probable de un hospedador intermediario. Es importante la unión de fuerzas entre la sanidad animal, la salud humana y la sanidad ambiental, en el contexto de Una sola Salud, para lograr el éxito en el control y erradicación de estas enfermedades

Expression of adrenomedullin and proadrenomedullin N-terminal 20 peptide in human and rat prostate

Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) are two recently discovered hypotensive peptides translated from the same message transcript (preproAM mRNA). In this article we report the presence of AM, PAMP, and their mRNA in human and rat prostate and of AM receptor mRNA in rat prostate. PreproAM mRNA was found in the epithelium of normal human and rat prostate glands by in situ hybridization. In humans, it was mainly expressed in the basal cells. In rat, its expression was higher in the ducts than in the acini of all the prostate lobes. Immunocytochemistry identified a similar distribution pattern for AM compared with its mRNA but showed different locations for AM and PAMP immunoreactivity. The former was widespread in the epithelia, whereas the latter was almost exclusively found in neuroendocrine cells. In rat, Western blot analysis confirmed the presence of high levels of AM peptide in the ventral lobe and of its precursor in the ventral and dorsolateral lobes. Immunoreactivity for serotonin, chromogranin A, PAMP, and AM defined four subpopulations of prostate neuroendocrine-like cells in rat, a cell type that has not been previously described

The experience of inflammatory bowel disease patients with healthcare: A survey with the IEXPAC instrument

Inflammatory bowel disease; Patients experience; Chronic diseaseMalaltia intestinal inflamatòria; Experiència dels pacients; Malalties cròniquesEnfermedad intestinal inflamatoria; Experiencia de los pacientes; Enfermedades crónicasTo assess inflammatory bowel disease (IBD) patients' experience of chronic illness care and the relationship with demographic and healthcare-related characteristics.This cross-sectional survey used the Instrument to Evaluate the EXperience of PAtients with Chronic diseases (IEXPAC) questionnaire to identify parameters associated with a better healthcare experience for IBD patients. IEXPAC questionnaire responses are grouped into 3 factors - productive interactions, new relational model, and patient self-management, scoring from 0 (worst) to 10 (best experience). Scores were analyzed by bivariate comparisons and multiple linear regression models.Surveys were returned by 341 of 575 patients (59.3%, mean age 46.8 (12.9) years, 48.2% women). Mean (SD) IEXPAC score was 5.9 (2.0); scores were higher for the productive interactions (7.7) and patient self-management factors (6.7) and much lower for the new relational model factor (2.2). Follow-up by a nurse, being seen by the same physician, and being treated with a lower number of medicines were associated with higher (better) overall patient experience score, and higher productive interactions and self-management factor scores. A higher productive interactions score was also associated with patients receiving medication subcutaneously or intravenously. Higher new relational model scores were associated with follow-up by a nurse, affiliation to a patients' association, receiving help from others for healthcare, a lower number of medicines and a higher educational level.In patients with IBD, a better overall patient experience was associated with follow-up by a nurse, being seen by the same physician, and being treated with a lower number of medicines