1,913 research outputs found
Influence of the accommodation coefficient on nonlinear bubble oscillations
This paper numerically investigates the effect of mass transfer processes on spherical single bubble
dynamics using the Hertz–Langmuir–Knudsen approximation for the mass flux across the interface.
Bubble behavior, with and without mass transfer, is studied for different values of pressure wave
amplitude and frequency, as well as initial bubble radius. Whereas mass transfer processes do not
seem to play a significant role on the bubble response for pressure amplitudes smaller than 0.9 atm,
they appear to have an important effect when the amplitude is greater than or equal to 1 atm. For
the later case, where the minimum liquid pressure reaches values around its vapor pressure, the
importance of mass transfer depends on frequency. For frequencies in the 10^3–10^5 Hz range and
initial bubble radii of the order of tens of microns, bubble implosions with and with no mass transfer
are significantly different; smaller radii display a lower sensitivity. In this regime, accurate model
predictions must, therefore, carefully select the correct value of the accommodation coefficient. For
frequencies greater than 10^5 Hz, as a first approximation mass transfer can be ignored
Análisis de la morbi-mortalidad a largo plazo en trasplante hepático
Consultable des del TDXTítol obtingut de la portada digitalitzadaAIMS. To retrospectively review our liver transplant performance to identify factors that influenced late mortality and morbidity. METHODS. Clinical records from 279 patients with liver transplants performed in Hospital Vall d'Hebron between January 1991and December 2001 and one year of survival, were reviewed. Minimal outcome was two years (r:1yr-12yr). Medium outcome was 9 years. The data evaluated by univariate and multivariate analyses regarding clinical outcome. RESULTS. Recipients mean was 55±5years, with 11%>65 years and 65% was male. Main indication for transplantation was postnecrotic cirrhosis (60%), followed by CHC in addition to cirrhosis (28%), choleostatic cirrhosis (6%), fulminant hepatitis (2%), Budd-Chiari (1%) and metabolic cirrhosis (1%). Half of the recipients (54%) were infected by HCV. A great percentage of recipients (44%) were at Child-Pugh C stage. Concomitant diseases were: renal insufficiency in 11%, arterial hypertension in 9%, diabetes mellitus in 16% and portal thrombosis in 18%. Inmunosupression at last the first year of liver transplantation was with cyclosporina in 108 patients (39%) and tacrolimus in 169 patients (60%). Patient actuarial survival what live at least a year, was 94%, 89%, 79% and 60% at 2yr, 3yr, 5yr and 10yr respectively. Seventy-five patients died in the outcome. Causes of death were recurrence primary disease in 11%, medical complications in 7% and de novo tumors in 5%. Rate of retransplant was 10% (27 patients). From all the pre-operative variables that appeared significant in univariate analysis, the factors that showed independent predictive value of late mortality were: old recipient (OR 1,03) , renal disfunction in the first year postransplant (OR 2,1) and liver disfunction at last the first year postransplant (OR 2,2). Characteristics of the patients with the risk factor of mortality «renal disfunction», were: >60 years, renal disfunction pretransplant or in the first year postransplant and Cyclosporine in the induction. Characteristics of the patients with the risk factor of mortality «liver disfunction», were: HCV pretransplant, HCV recurrence in the first year, acute rejection in the first year and Cyclosporine in the induction. The mean long term complications in liver transplant were: arterial hypertension in 50%, renal disfunction in 49%, diabetes mellitus in 30%, hypercholesterolaemia in 19%, hypertriglyceridaemia in 18%, cardiovascular complications in 15% and de novo tumors in 14%. From all the preoperative variables that appeared significant in univariate analysis, the factors that showed independent predictive value of late morbidity were: 1. Renal disfunction: old recipient, pretransplant cardiovascular complications and long stay in the hospital of the recipient. 2. Arterial hypertension: pretransplant arterial hypertension and CHC pretransplant in the recipient, donor exitus by traffic accident. 3. Diabetes Mellitus: pretransplant diabetes and HCV pretransplant in the recipient 4. Hypercholesterolaemia: no risk factors. Tacrolimus in the first year postransplantation is protector factor. 5. Hypertriglyceridaemia: cold ischaemia time>8h, donor male, intraoperative transfusion of platelets, long stay in ICU of the recipient. 6. Cardiovascular complications: old recipient and pretransplant cardiovascular complications, long time since of transplantation. 7. De novo tumors: old recipient. CONCLUSIONS. Old recipient, renal disfunction in the first year and liver disfunction at last the first year postTH are the most significant risk factor for late mortality. Arterial hypertension, renal disfunction and diabetes mellitus are the mean long term complications in liver transplantation, and the most significance risk factors are old recipient, HCV preTH, arterial hypertension and diabetes mellitus preTH, young donor and use Cyclosporine in the inmunosupression
Transforming the health system into an open ended prospective clinical study by using artificial intelligence on clinical big data/ real word data
Because of the continuous decrease of sequencing prices the GA4GH has estimated
that by 2023 over 80% of sequencing will be done in a clinical environment. In addition,
more than two decades of generalized digitalization of health systems is generating an
immense repository of clinical big data. Moreover, in coming years wearable devices will
be mainstream for monitoring chronic patients and the elder, producing an enormous
amount of health and life style data. On the other hand, the field of artificial intelligence
has experienced an enormous activity in the last years, releasing a plethora of new
methods or new versions of classical ones, able to find patterns in large datasets, to
produce classifications using highly dimensionality data or to derive predictors of unprecedented precision. All this together offer an unprecedented opportunity to analyze this
wealth of real world data (RWD) to generate new biomedical knowledge with an enormous
translational potential. However, several obstacles preclude the direct exploitation
of this data. Firstly, most of this data are highly sensitive and are consequently affected
by data protection laws and regulations, which impose severe regulations to its use,
especially outside of the health system. Moreover, much of this data are contained in
unconnected silos in a non-homogeneous format. Here we will comment some initiatives
to integrate genomic and clinical data within the Andalusian Public Health System
and to make a systematic exploitation to generate new biomedical knowledge using
artificial intelligence
Systems medicine approach to model cell signaling activity uncovers disease mechanisms and predicts cancer outcome
Motivation: Gene expression measurements (microarray of RNA-seq) are affordable ways to survey cell activity. However, they constitute low-informative, decontextualized values that often lack a mechanistic link with real cell functional outcomes. Mathematical modeling of biological pathways is emerging as a useful tool to understand the molecular mechanisms that govern the cell behavior or fate, revealing disease mechanisms and drug mechanisms of action, and providing guidance on therapeutic decisions (Gustafsson et al., 2014). Methods: Signaling KEGG pathways are used as basic maps of cell functionality over which gene expression values are modeled to obtain probabilities of signal transduction and, consequently, cell function activations (Hidalgo et al, 2017).Results: Here we propose a new method that models cell signaling using biological knowledge on signal transduction (Hidalgo et al., 2017). The method recodes individual gene expression values (and/or gene mutations) into accurate measurements of changes in the activity of signaling circuits, which ultimately constitute high-throughput estimations of cell functionalities caused by gene activity within the pathway. Signaling circuit activities can predict cancer outcome and have also demonstrated to be excellent predictors of drug response (Amadoz et al., 2015)Conclusions: A comprehensive, systems-based understanding of the way in which genes interact to shape the phenotype is required to realistically manage complex diseases
Positive Selection, Relaxation, and Acceleration in the Evolution of the Human and Chimp Genome
For years evolutionary biologists have been interested in searching for the genetic bases underlying humanness. Recent efforts at a large or a complete genomic scale have been conducted to search for positively selected genes in human and in chimp. However, recently developed methods allowing for a more sensitive and controlled approach in the detection of positive selection can be employed. Here, using 13,198 genes, we have deduced the sets of genes involved in rate acceleration, positive selection, and relaxation of selective constraints in human, in chimp, and in their ancestral lineage since the divergence from murids. Significant deviations from the strict molecular clock were observed in 469 human and in 651 chimp genes. The more stringent branch-site test of positive selection detected 108 human and 577 chimp positively selected genes. An important proportion of the positively selected genes did not show a significant acceleration in rates, and similarly, many of the accelerated genes did not show significant signals of positive selection. Functional differentiation of genes under rate acceleration, positive selection, and relaxation was not statistically significant between human and chimp with the exception of terms related to G-protein coupled receptors and sensory perception. Both of these were over-represented under relaxation in human in relation to chimp. Comparing differences between derived and ancestral lineages, a more conspicuous change in trends seems to have favored positive selection in the human lineage. Since most of the positively selected genes are different under the same functional categories between these species, we suggest that the individual roles of the alternative positively selected genes may be an important factor underlying biological differences between these species
Fortaleciendo redes y frenando campos experimentales
Un relato de resistencia ciudadana con un buen final. Una obra coral, donde el reparto es clave y no existen secundarios, cada persona improvisa pero a la vez conoce su papel. Y el escenario puede ser cualquiera de nuestros territorios
Mommy Dearest?: Postpartum Psychosis, The American Legal System, And The Criminalization Of Mental Illness
Children are often regarded as the most sacred beings in all of society—appealing to our collective sense of human dignity and protecting the most vulnerable. Mothers fiercely protecting their young children from perceived dangers is ostensibly a natural and moral response. This notion of the loving mother is in stark contrast to filicide, or the act of a parent murdering their child. It is a bedrock principle of the American criminal-justice system that a defendant is not responsible for their actions if the defendant was “laboring under such a defect of reason, from a disease of the mind, as not to know the nature and quality of the act he was doing or, if he did know it, that he did not know what he was doing was wrong.”1 Given the bleak reality of filicide, how should American criminal law treat mothers who commit the heinous crime of killing their child when the mother was suffering from a postpartum disorder at the time of the crime? This essay will detail women’s lived experiences of postpartum disorders, describe the current American criminal law approach to defendants who are mentally ill, and propose changes to American criminal procedure to reflect postpartum disorders’ effect on a mother’s mental state
Un día para hablar de nosotras
El artículo cuenta con la colaboración de Ángeles Santos Alfonso, Gemma Flores Pons, Isabel Díez Leiva y Leticia Toledo Martín.La economía feminista se construye en el día a día, sin recetas, a base de convicciones, sensaciones, experiencias y reflexiones, desde cualquier ámbito de la vida. Para acercarnos a esta construcción desde lo rural, desde la agroecología y la soberanía alimentaria, propiciamos un encuentro entre cuatro mujeres que desde diferentes actividades y territorios, aportan y tejen esta red. Reproducimos una parte de lo mucho que se habló
Poblaciones de peces salvajes: ¿responsables o sufridores de las patologías virales en acuicultura?
El desarrollo de la acuicultura en las últimas décadas ha sido el motor que ha favorecido el avance de la virología de peces. El número de grupos de investigación dedicados a esta disciplina ha ido incrementándose progresivamente, lo que ha implicado un crecimiento exponencial del conocimiento científico y el desarrollo tecnológico, y ha permitido mejoras en la prevención y el control de este tipo de patologías, que representan uno de los mayores temores del Sector.
El estudio de los virus que afectan a peces en cultivo se beneficia de las especiales condiciones del mismo: área delimitada, poblaciones bien definidas y con un historial conocido, seguimiento de morbilidades y mortalidades –que aportan individuos en los que las altas cargas virales facilitan el diagnóstico y el estudio del agente causal– y disponibilidad de especímenes para experimentación científica. Estas condiciones, sin embargo, están ausentes –en la mayor parte de los casos– en ambientes naturales, sobre todo cuando se estudian entornos oceánicos. Éste es, con toda seguridad, el porqué de que, en las más de cinco décadas del marcado crecimiento de la investigación en esta área, el número de publicaciones científicas enfocadas a poblaciones salvajes no llegue a los 300.
Sin embargo, en un número –creciente– de grupos se ha despertado el interés por conocer el estado sanitario de las poblaciones salvajes y silvestres de peces en todo el mundo. Fundamentalmente, pero no sólo, se pone la diana en aquellas poblaciones que pueden estar en la interfase de interacción con la acuicultura. Sin embargo, destaca también la lista creciente de campañas oceanográficas cuyo único fin inicial es el conocimiento del estado epidemiológico de poblaciones teóricamente muy alejadas, pero que han aportado interesantes datos que demuestran que la globalización ha existido en los océanos desde mucho antes que el Hombre inventara ese concepto.
Los primeros trabajos de monitorización de poblaciones salvajes, que datan de mediados de los 70, estaban centrados en el estudio de la presencia del virus de la necrosis pancreática infecciosa (IPNV) en peces de lagos escoceses; hacia finales de esa década, se descubrió la presencia del virus de la septicemia hemorrágica viral (VHSV) en bacalao salvaje en la costa sur de Dinamarca. A lo largo de todos estos años, ambos virus han seguido siendo el objetivo de la mayor parte de las campañas de monitorización de este tipo de poblaciones de peces. Otros virus que han ido despertando el interés de los científicos son el virus de la necrosis nerviosa viral (VNNV) y el virus de la anemia infecciosa del salmón. Pero, hay una gran variedad de virus que han sido y son objeto de estudio en poblaciones naturales, y otros muchos –aún desconocidos– que, con toda seguridad, están esperando a ser descubiertos por los investigadores (como resultado de su estudio) o por los piscicultores en sus plantas de cultivo (como resultado de su efecto). No en vano todos estos virus representan una gran preocupación para los piscicultores, para los cuales –y también para algunos científicos– es tentador culpar a las poblaciones salvajes de las patologías emergentes y re-emergentes en acuicultura.
Si bien es cierto que hay algunos estudios que demuestran –o pretenden demostrar–, en ocasiones con pruebas circunstanciales, que el efecto de dispersión de agentes virales desde ambientes naturales a la acuicultura no es recíproco, no se puede descartar el efecto amplificador que el cultivo intensivo de peces tiene sobre los agentes infecciosos, lo que hace que una gran carga viral pueda ser devuelta al medio. Por otro lado, sí está demostrado que el especial ecosistema del cultivo intensivo representa una presión adaptativa que acelera el reloj evolutivo de los virus en cuanto entran en ese entorno. Esto puede implicar que las poblaciones salvajes supuestamente responsables de una epizootia determinada se conviertan en poblaciones naif en cuanto reciban el virus devuelto por la población cultivada. La diferencia es que generalmente –aunque hay unos pocos casos demostrados– las mortalidades masivas en las poblaciones salvajes se nos pasan desapercibidas.
No obstante, a pesar de los esfuerzos de muchos científicos, que hemos llegado a estar bajo el paraguas de una red internacional (DIPNET: Disease Interactions and Pathogens Exchange Network), sólo unos pocos casos de interacción salvaje-doméstico han podido ser confirmados. En este trabajo, aprovecho la oportunidad para dar unas pinceladas sobre el estado en que se encuentra el conocimiento del estatus epidemiológico de las poblaciones salvajes, el efecto de globalización de las corrientes, migraciones y la mano del hombre, y lo que puede ocurrir en la zona de interfase medio salvaje-acuicultura, así como qué medidas podemos tomar para reducir su efecto.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec
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