Donor impurity-related linear and nonlinear intraband optical absorption coefficients in quantum ring : effects of applied electric field and hydrostatic pressure

ABSTRACT: The linear and nonlinear intraband optical absorption coefficients in GaAs three-dimensional single quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and electric field, applied along the growth direction of the heterostructure, the energies of the ground and first excited states of a donor impurity have been found using the effective mass approximation and a variational method. The energies of these states are examined as functions of the dimensions of the structure, electric field, and hydrostatic pressure. We have also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as a function of incident photon energy for several configurations of the system. It is found that the variation of distinct sizes of the structure leads to either a redshift and/or a blueshift of the resonant peaks of the intraband optical spectrum. In Maddition, we have found that the application of an electric field leads to a redshift, whereas the influence of hydrostatic pressure leads to a blueshift (in the case of on-ring-center donor impurity position) of the resonant peaks of the intraband optical spectrum

Presente y futuro del trasplante de islotes pancreáticos, un tratamiento innovador para la diabetes tipo 1

Introducción El trasplante de islotes pancreáticos (TI*) se ha convertido en una opción terapéutica prometedora para algunos pacientes diabéticos con historia de hipoglicemia frecuentemente no percibida y labilidad glicémica severa. A pesar de ser un procedimiento relativamente joven en el área de trasplante de órganos y células, en las dos últimas décadas el TI pasó de ser una curiosidad quirúrgica en el área de trasplantes a posicionarse como una realidad terapéutica. esto gracias al desarrollo de novedosos protocolos de TI que proponen una nueva terapia de inmunosupresión, preparación de islotes de alta calidad, recepción de tejido proveniente de múltiples donantes y selección cuidadosa de candidatos para trasplante. Los principales avances obtenidos en la década pasada en el TI fueron introducidos por el Protocolo de edmonton en el año 2000, el cual incluyó varias modificaciones, entre ellas el uso de un esquema de inmunosupresión libre de corticoesteroides y una masa de trasplante de 11.000 Ie/kg (Ie: islotes equivalentes), mejorando significativamente los resultados hasta entonces obtenidos en pacientes sometidos a TI. De los datos evaluados en los 65 pacientes sometidos a TI bajo este protocolo, se destaca que la mayoría logró independencia de la insulina durante el primer año y mejoría en la inestabilidad glicémica a los cinco años postrasplante. sin embargo, sólo 7,5% de los pacientes adquirieron independencia de la insulina luego de cinco años. Estos resultados permitieron revelar el TI al ámbito científico como un campo investigativo promisorio, con grandes necesidades de avances futuros para conseguir una preservación de la función de los islotes trasplantados a largo plazo(4), lo que promovió ampliamente la investigación sobre el tema y la creación de centros especializados desde entonces alrededor del mundo

Variaciones en el número y función de los linfocitos asesinos naturales durante infecciones recurrentes o graves

Introduction: The information about defects affecting natural killer cell (NK) development and activity in patients with an abnormal increase of recurrent infections is scarce.Objective: To perform a systematic analysis of NK abnormalities in patients with recurrent infections.Materials and methods: Our study enrolled twenty patients with severe or recurrent viral infections. Natural killer cell subsets, surface receptors expression and cytotoxicity were analyzed. Results were compared with those from age- and sex-matched healthy controls.Results: Transient alterations were observed in the percentages and absolute numbers of NK cells in patients with infection active episodes. We also described five patients with stable disturbances in the distribution of NK cell subpopulations. These defects are mainly due to a decrease in the CD56dimCD16bright cells in peripheral blood. In addition, NK cell function abnormalities were observed in some patients, however, those were always transient and mainly associated to active disease.Conclusions: These findings demonstrate transient alterations in the percentages and absolute numbers of NK cells in patients with recurrent or severe infection. Also, stable disturbances in CD56dimCD16bright NK cells are observed in these patients. Nevertheless, these parameters must be thoroughly studied to determine the mechanisms that entail these immune abnormalities and investigate how they alter the immune response.Introducción. Existen pocos datos sobre los defectos que afectan el desarrollo y función de los linfocitos asesinos naturales (natural killers, NK) en pacientes con un incremento anormal en la recurrencia de infecciones.Objetivo. Realizar una evaluación sistemática de las diferentes subpoblaciones y la función de estas células en pacientes con infecciones recurrentes.Materiales y métodos. Se incluyeron 20 pacientes con infecciones graves o recurrentes y se analizaron las subpoblaciones y la respuesta citotóxica de los linfocitos NK en sangre periférica. Los resultados de los pacientes se compararon con controles sanos pareados por edad y sexo.Resultados. Los pacientes con episodios infecciosos activos presentaron anormalidades transitorias en el porcentaje o el número absoluto de linfocitos NK. Se caracterizaron, además, cinco pacientes con alteraciones persistentes en la distribución de las subpoblaciones de linfocitos NK. Estas alteraciones se debieron principalmente a la disminución de células CD56dimCD16bright. Se evidenciaron, también, defectos en la función de los linfocitos NK en algunos de nuestros pacientes; sin embargo, estas alteraciones fueron transitorias y se asociaron principalmente a la fase activa de la enfermedad.Conclusiones. Nuestros resultados evidencian defectos transitorios en el número y función de los linfocitos NK en pacientes con infecciones recurrentes o graves, además de alteraciones persistentes en los LNK CD56dimCD16bright en algunos individuos. Es necesario profundizar en los mecanismos que conllevan al desarrollo de estos defectos inmunes y estudiar cómo estas alteraciones influyen en la respuesta inmune

Primer trasplante de islotes realizado en Colombia, experiencia fundación Valle del Lili

Introducción De acuerdo con las estadísticas suministradas en el 2014 por la Federación Internacional de Diabetes, la prevalencia de pacientes con diabetes está en aumento a nivel mundial, actualmente alrededor de 382 millones de personas sufren de esta patología. En relación con la diabetes tipo 1 se estima que corresponde al 5% de todos los casos diagnosticados de diabetes en adultos. Para el caso de Colombia, la incidencia de diabetes tipo 1 es de 3-4 por 100.000 niños menores de 15 años y la prevalencia se estima en 0,07%. Para el municipio de Santiago de Cali, según datos de la oficina de estadística de la Secretaría de Salud Pública, la diabetes (tipo 1 y 2) se encuentra entre las diez primeras causas de muerte en la ciudad, ocupando el octavo lugar en el grupo de hombres y el séptimo entre las mujeres. Cabe resaltar que la prevalencia de diabetes para Cali es del 6,76%, seguida del 5,4% para el departamento del Valle del Cauca, cifra mucho más alta cuando se compara con la prevalencia nacional que es de 2%. Específicamente, cuando nos referimos a la diabetes tipo 1, es una patología autoinmune crónica, que se presenta con una predisposición genética específica y en un 0,4% aparece sin antecedentes familiares. Su presentación se hace de forma inesperada, a causa de la destrucción rápidamente progresiva de las células beta pancreáticas, por esta razón requiere la suplencia total de insulina exógena de forma crónica. Lo anterior ocasiona que la enfermedad esté ligada a una carga económica alta para los pacientes, sus familias y el sistema de salud. A nivel global se estima que más del 10% de la inversión en salud se destina a gastos relacionados directamente con diabetes. En cuanto al tratamiento médico de la diabetes tipo 1, la recomendación actual está basada en la terapia intensiva con insulina exógena, sin embargo, este tratamiento se caracteriza por ser de difícil adherencia, costoso, y por conllevar a un incremento considerable de los eventos de hipoglicemia severa. Estos eventos aumentan en alto grado el riesgo de sufrir deterioro cardiovascular y cognitivo. Por lo tanto, existe una gran necesidad de encontrar mejores alternativas de tratamiento para estos pacientes, que impliquen menores riesgos biológicos y ofrezcan mejor calidad de vida

Antología del pensamiento Social en Colombia

PublishedEl quehacer de la filosofía no es límite de este ejercicio, la recopilación de estos documentos trata de un ejercicio interdisciplinar. La sociología, la historia, la antropología y otras disciplinas se abren campo en esta indagación; quizá esto sea parte del carácter original del pensamiento social: el ejercicio académico dialógico. Así, la conjugación de ciencias, miradas e indagaciones es el carácter prioritario y, sin embargo, cada documento se muestra lejos del que lo precede y del que lo antecede. Por pensamiento social, entonces, entiéndase la episteme que rigurosa y profundamente revisa ideas, pensamientos, teorías y realidades en aras a fortalecer una construcción crítica de la esfera pública. El saber se construye con un fin práctico y con una naturaleza plural, es decir, el fin es la construcción de comprensiones prácticas y críticas en torno a las necesidades de lo social, que tienen en su naturaleza la pluralida

White Noise Speech Illusions: A Trait-Dependent Risk Marker for Psychotic Disorder?

Introduction: White noise speech illusions index liability for psychotic disorder in case-control comparisons. In the current study, we examined i) the rate of white noise speech illusions in siblings of patients with psychotic disorder and ii) to what degree this rate would be contingent on exposure to known environmental risk factors (childhood adversity and recent life events) and level of known endophenotypic dimensions of psychotic disorder [psychotic experiences assessed with the Community Assessment of Psychic Experiences (CAPE) scale and cognitive ability]. Methods: The white noise task was used as an experimental paradigm to elicit and measure speech illusions in 1,014 patients with psychotic disorders, 1,157 siblings, and 1,507 healthy participants. We examined associations between speech illusions and increasing familial risk (control -> sibling -> patient), modeled as both a linear and a categorical effect, and associations between speech illusions and level of childhood adversities and life events as well as with CAPE scores and cognitive ability scores. Results: While a positive association was found between white noise speech illusions across hypothesized increasing levels of familial risk (controls -> siblings -> patients) [odds ratio (OR) linear 1.11, 95% confidence interval (CI) 1.02-1.21, p = 0.019], there was no evidence for a categorical association with sibling status (OR 0.93, 95% CI 0.79-1.09, p = 0.360). The association between speech illusions and linear familial risk was greater if scores on the CAPE positive scale were higher (p interaction = 0.003; ORlow CAPE positive scale 0.96, 95% CI 0.85-1.07; ORhigh CAPE positive scale 1.26, 95% CI 1.09-1.46); cognitive ability was lower (p interaction < 0.001; ORhigh cognitive ability 0.94, 95% CI 0.84-1.05; ORlow cognitive ability 1.43, 95% CI 1.23-1.68); and exposure to childhood adversity was higher (p interaction < 0.001; ORlow adversity 0.92, 95% CI 0.82-1.04; ORhigh adversity 1.31, 95% CI 1.13-1.52). A similar, although less marked, pattern was seen for categorical patient-control and sibling-control comparisons. Exposure to recent life events did not modify the association between white noise and familial risk (p interaction = 0.232). Conclusion: The association between white noise speech illusions and familial risk is contingent on additional evidence of endophenotypic expression and of exposure to childhood adversity. Therefore, speech illusions may represent a trait-dependent risk marker

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Daily use of high-potency cannabis is associated with more positive symptoms in first-episode psychosis patients: the EU-GEI case-control study.

BACKGROUND: Daily use of high-potency cannabis has been reported to carry a high risk for developing a psychotic disorder. However, the evidence is mixed on whether any pattern of cannabis use is associated with a particular symptomatology in first-episode psychosis (FEP) patients. METHOD: We analysed data from 901 FEP patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. We used item response modelling to estimate two bifactor models, which included general and specific dimensions of psychotic symptoms in patients and psychotic experiences in controls. The associations between these dimensions and cannabis use were evaluated using linear mixed-effects models analyses. RESULTS: In patients, there was a linear relationship between the positive symptom dimension and the extent of lifetime exposure to cannabis, with daily users of high-potency cannabis having the highest score (B = 0.35; 95% CI 0.14-0.56). Moreover, negative symptoms were more common among patients who never used cannabis compared with those with any pattern of use (B = -0.22; 95% CI -0.37 to -0.07). In controls, psychotic experiences were associated with current use of cannabis but not with the extent of lifetime use. Neither patients nor controls presented differences in depressive dimension related to cannabis use. CONCLUSIONS: Our findings provide the first large-scale evidence that FEP patients with a history of daily use of high-potency cannabis present with more positive and less negative symptoms, compared with those who never used cannabis or used low-potency types.The work was supported by: Clinician Scientist Medical Research Council fellowship (project reference MR/M008436/1) to MDF; the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care South London at King's College Hospital NHS Foundation Trust to DQ; DFG Heisenberg professorship (no. 389624707) to UR. National Institute for Health Research (NIHR) Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King’s College London. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care. The EU-GEI Project is funded by the European Community’s Seventh Framework Programme under grant agreement No. HEALTH-F2-2010-241909 (Project EU-GEI). The Brazilian study was funded by the São Paulo Research Foundation under grant number 2012/0417-0

The continuity of effect of schizophrenia polygenic risk score and patterns of cannabis use on transdiagnostic symptom dimensions at first-episode psychosis: findings from the EU-GEI study.

Diagnostic categories do not completely reflect the heterogeneous expression of psychosis. Using data from the EU-GEI study, we evaluated the impact of schizophrenia polygenic risk score (SZ-PRS) and patterns of cannabis use on the transdiagnostic expression of psychosis. We analysed first-episode psychosis patients (FEP) and controls, generating transdiagnostic dimensions of psychotic symptoms and experiences using item response bi-factor modelling. Linear regression was used to test the associations between these dimensions and SZ-PRS, as well as the combined effect of SZ-PRS and cannabis use on the dimensions of positive psychotic symptoms and experiences. We found associations between SZ-PRS and (1) both negative (B = 0.18; 95%CI 0.03-0.33) and positive (B = 0.19; 95%CI 0.03-0.35) symptom dimensions in 617 FEP patients, regardless of their categorical diagnosis; and (2) all the psychotic experience dimensions in 979 controls. We did not observe associations between SZ-PRS and the general and affective dimensions in FEP. Daily and current cannabis use were associated with the positive dimensions in FEP (B = 0.31; 95%CI 0.11-0.52) and in controls (B = 0.26; 95%CI 0.06-0.46), over and above SZ-PRS. We provide evidence that genetic liability to schizophrenia and cannabis use map onto transdiagnostic symptom dimensions, supporting the validity and utility of the dimensional representation of psychosis. In our sample, genetic liability to schizophrenia correlated with more severe psychosis presentation, and cannabis use conferred risk to positive symptomatology beyond the genetic risk. Our findings support the hypothesis that psychotic experiences in the general population have similar genetic substrates as clinical disorders

Chemical composition and antigenotoxic properties of Lippia alba essential oils

The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33% geranial and 25% neral), geraniol (7%) and trans-β-caryophyllene (7%) for L. alba specimen COL512077, and carvone (38%), limonene (33%) and bicyclosesquiphellandrene (8%) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds