168 research outputs found
Conceptual and basic design of a stirling engine prototype for electrical power generation using solar energy
The research consisted in a conceptual and basic design of a prototype Stirling engine with the purpose of taking advantage of the solar radiation to produce electric energy. The
work began with a bibliography review covering aspects as history, basic functioning, design configurations, applications and analysis methods, just to continue with the conceptual design, where the prototype specifications were determined. Finally, a basic dimensioning of the important components as heat exchangers (heater, cooler, and regenerator), piston, displacer and solar collector was elaborated. The principal conclusions were that the different analysis methods had dissimilitude among their results; in this sense, a construction of the prototype is necessary for the understanding of the complex phenomena occurring inside the engin
CXCR4(+)-targeted protein nanoparticles produced in the food-grade bacterium Lactococcus lactis
Lactococcus lactis is a Gram-positive (endotoxin-free) food-grade bacteria exploited as alternative to Escherichia coli for recombinant protein production. We have explored here for the first time the ability of this platform as producer of complex, self-assembling protein materials. Materials & methods: Biophysical properties, cell penetrability and in vivo biodistribution upon systemic administration of tumor-targeted protein nanoparticles produced in L. lactis have been compared with the equivalent material produced in E. coli. Results: Protein nanoparticles have been efficiently produced in L. lactis, showing the desired size, internalization properties and biodistribution. Conclusion: In vitro and in vivo data confirm the potential and robustness of the production platform, pointing out L. lactis as a fascinating cell factory for the biofabrication of protein materials intended for therapeutic applications.Award-winningPostprint (published version
Diversity of Potassium Channels in Human Umbilical Artery Smooth Muscle Cells: A Review of Their Roles in Human Umbilical Artery Contraction
Through their control of cell membrane potential, potassium (K(+)) channels are among the best known regulators of vascular tone. This article discusses the expression and function of K(+) channels in human umbilical artery smooth muscle cells (HUASMCs). We review the bibliographic reports and also present single-channel data recorded in freshly isolated cells. Electrophysiological properties of big conductance, voltage- and Ca(2+)-sensitive K(+) channel and voltage-dependent K(+) channels are clearly established in this vessel, where they are involved in contractile state regulation. Their role in the maintenance of membrane potential is an important control mechanism in the determination of the vessel diameter. Additionally, small conductance Ca(2+)-sensitive K(+) channels, 2-pore domains K(+) channels and inward rectifier K(+) channels also appear to be present in HUASMCs, while intermediate conductance Ca(2+)-sensitive K(+) channels and ATP-sensitive K(+) channels could not be identified. In both cases, additional investigation is necessary to reach conclusive evidence of their expression and/or functional role in HUASMCs. Finally, we discuss the role of K(+) channels in pregnancy-related pathologies like gestational diabetes and preeclampsia.Fil: Martín, Pedro. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Grupo de Investigación en Fisiología Vascular; ArgentinaFil: Rebolledo, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Grupo de Investigación en Fisiología Vascular; ArgentinaFil: Roldan Palomo, Ana Rocio. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Grupo de Investigación en Fisiología Vascular; ArgentinaFil: Moncada, Melisa. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Grupo de Investigación en Fisiología Vascular; ArgentinaFil: Piccinini, Luciano. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Grupo de Investigación en Fisiología Vascular; ArgentinaFil: Milesi, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Grupo de Investigación en Fisiología Vascular; Argentin
Ultrasonic radiation influence on the bioadsorbent characteristics of citrus (citrus x lemon) & (citrus x sinensis)
Of all the materials used as adsorbents, activated charcoal is the most popular as it is excellent for reducing/eliminating a wide variety of contaminants. This capacity is mainly due to its structural characteristics that give it a large surface area. However, it has several disadvantages. The most important are that the adsorbent material is quite expensive as is its regeneration. For this reason, more economical absorbents have been sought, highlighting the study of adsorption phenomena in some types of biomass as adsorbents. Bioadsorption is considered a viable alternative to the physical-chemical methods currently used for the recovery or removal of heavy metals dissolved in liquid effluents. Its main attraction, from an industrial point of view, is its low cost due to the great abundance, easy to obtain and low price of the bioadsorbent material. Bioadsorption is very effective in treating metal concentrations below 100 mg/L, where the application of physical-chemical methods is neither technically nor economically feasible. One of these materials of interest is citrus peels, because, due to their abundance as a waste product of the food industries, they are hardly reused and currently have little economic value. However, these residues have a low adsorption capacity, so both physical and chemical modifications are required to increase their adsorption properties. This study compares the characteristics of orange and lemon peels undergoing a physical-chemical treatment with ultrasonic radiation assistance and the optimization of experimental conditions to obtain useful bioadsorbents in discontinuous processes (batch)Postprint (published version
Artificial Formate Oxidase Reactivity with Nano-Palladium Embedded in Intrinsically Microporous Polyamine (Pd@PIM-EA-TB) Driving the H<sub>2</sub>O<sub>2</sub> – 3,5,3’,5’-Tetramethylbenzidine (TMB) Colour Reaction
Surface cavities formed by molecularly rigid polymers of intrinsic microporosity affect catalytic processes. Palladium nanoparticles of typically 3 nm diameter are formed in an intrinsically microporous polyamine (PIM-EA-TB) by borohydride reduction. These particles are shown to indirectly catalyse the oxidative colour change of indicator dye 3,5,3′,5′-tetramethylbenzidine (TMB) in the presence of formic acid via formation of H2O2. Investigation reveals that oxygen reduction on the palladium is rate limiting with optimised H2O2 production at approximately pH 3 to 4, and first order in formate, followed by purely homogeneous TMB oxidation. The H2O2 production is therefore studied separately as a nanozyme-like catalytic process equivalent to formate oxidase reactivity, linked to the molecularly rigid polyamine host (PIM-EA-TB) providing ammonium sites (in molecularly rigid surface cavities) that enhance both (i) 2-electron formate oxidation and (ii) 2-electron oxygen reduction to H2O2. Beneficial effects of hydrophobic ClO4- anions are noted as indirect evidence for the effect of ammonium sites in surface cavities. A computational DFT model for the artificial formate oxidase reactivity is developed to underpin and illustrate the hypothesis of PIM-EA-TB as an active catalyst component with implications for future nanozyme sensor development
Antibody-Antigen Binding Interface Analysis in the Big Data Era
Antibodies have become the Swiss Army tool for molecular biology and nanotechnology. Their outstanding ability to specifically recognise molecular antigens allows their use in many different applications from medicine to the industry. Moreover, the improvement of conventional structural biology techniques (e.g., X-ray, NMR) as well as the emergence of new ones (e.g., Cryo-EM), have permitted in the last years a notable increase of resolved antibody-antigen structures. This offers a unique opportunity to perform an exhaustive structural analysis of antibody-antigen interfaces by employing the large amount of data available nowadays. To leverage this factor, different geometric as well as chemical descriptors were evaluated to perform a comprehensive characterization.Fil: Reis, Pedro B. P. S.. Istituto Italiano Di Technologie; Italia. Universidade Nova de Lisboa; PortugalFil: Barletta Roldan, Patricio German. The Abdus Salam; Italia. The Abdus Salam. International Centre for Theoretical Physics; Italia. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gagliardi, Lucas. Istituto Italiano Di Technologie; ItaliaFil: Fortuna, Sara. Istituto Italiano Di Technologie; ItaliaFil: Soler, Miguel A.. Istituto Italiano Di Technologie; ItaliaFil: Rocchia, Walter. Istituto Italiano Di Technologie; Itali
Erectile Dysfunction Associated with Cardiovascular Risk Factors
Objectives: (1) Determine erectile dysfunction (ED) prevalence in patients with cardiovascular risk factors (CVRF). (2) Assess ED incidence in relation to the extent of controlling CVRF. Methodology: Patients: Enrolled participants came to the health centres in the study area. In accordance with the incidence of diseases with cardiovascular risks (CVR) in the Basic Health Regions of the study area, sample size was calculated with a 95% confidence interval and an alpha error of 0.005, resulting in a sample of 210 people, of which 30 could not complete the study for various reasons (change of address, death, refused to complete questionnaire, etc.). A full awareness and diffusion campaign was organized with talks and leaflets. Letters: A standard letter was given to patients which explained the importance of sexual health, offering them an appointment with a DUE (Diploma in Nursing) survey taker. The questionnaire was devised by the research group and was given by a fully trained DUE survey taker. Previously, contact was made with all the health centres, physicians and nursing staff to give them information on ED and CVRF and to inform them about the work to be done in their health region. Those patients who did not come to the appointment were telephoned to insist on the importance of attending and completing the questionnaire. Variables analysis: We analysed age, level of education, civil status, height, weight and body mass index (BMI), SBP, DBP, smoking habit, number cigarettes/day, year smoking began, ex‐smoker, year smoking stopped, alcohol consumption, grams alcohol/week, as well as consumption of other drugs, frequency and type. Blood test: glucose, haemoglobin glycated haemoglobin, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, artherogenic index, creatinine, urea, GOT, GPT, gamma‐GT and PSA. Urine test: micro‐albuminuria, proteinuria and creatinine clearance. ECG: Diabetes diagnosed at least 1 year ago and prescribed drugs to treat it. High blood pressure diagnosed at least 1 year ago and prescribed drugs to treat it. Dyslipidaemia (hypercholesterolaemia) diagnosed at least 1 year ago and prescribed drugs to treat it. Concomitant diseases of at least 1 year and drugs (up to 3) SHIM questionnaire and ED according to SHIM. Statistical analysis: an observational, descriptive, analytical, cross‐sectional study. Qualitative variables are presented as exact values and a percentage; quantitative variables as the mean and standard deviation (SD). A means comparison was done with the Student’s t‐test for independent groups, or the Mann‐Whitney U test if normality conditions (using the Kolmogorov‐Smirnoff or Shapiro‐Wilks test) were not fulfilled. The chi‐squared test was used for qualitative variables. Results: Of the 210 selected people, 179 completed the questionnaire (85.2%). The mean age was 64.5 ± 11.6 years. When analysing all the study variables in relation to the main variable, presence or absence of ED, age played an important role in ED appearing as ED incidence rises with age. Blood pressure had no significant relationship with the studied variable, and the same hold for BMI and its subdivision into normal weight and obesity. As regards toxic habits, neither cigarette smoking nor alcohol consumption influenced the presence of ED. The same hold for the sociological‐type variables (civil states, level of education). Regarding the biochemical variables from blood tests, a significant relationship with the atherogenic index and its recoded variable at high and low atherogenic risk (p < 0.04) was noted. In the glycaemic profile, a glycaemia mean of 126 mg/dl was obtained in the ED presence group, which is the cut‐off point proposed by ADA117 (American Diabetes Association) to consider a subject diabetic. Likewise, glycated haemoglobin presented figures in the two groups can be considered an alternation of a practically diabetic glucose metabolism. In our study, the presence of diabetic disease, high blood pressure (HBP) and dyslipidaemia showed no significant relationship with ED presence for each disease. However, in the combination of these diseases, a statistically significant relationship was seen when CVR increases, according to the Framinghan tables. Neither did each disease’s duration show a significant relationship with ED presence nor significant differences for the drugs used to treat the three pathologies were found. The coronary risk calculated according to the Framinghan tables indicated a statistically significant result, as did excessive risk (the difference between the coronary risk and the average assigned per age) for ED presence. The LISAT 8 test suggested that ED affected health‐associated quality of life and was statistically significant in two items of sex life and economic situation and was borderline statistically significant in the general life and working life items. Conclusions: There is a high ED prevalence in patients with high CVR. When ED improves, the better CVRFs are controlled. These patients’ pluripathology implies aggressive polymedication which doctors must consider as it increases the risk of ED
Personality changes in patients suffering from drug-resistant epilepsy after surgical treatment : a 1-year follow-up study
Acord transformatiu CRUE-CSICObjective: To determine changes in dimensions of personality in a sample of patients suffering from drug-resistant epilepsy at the 1-year follow-up following surgery, compared to non-surgically treated controls. Methods: We conducted a prospective comparative controlled study, including drug-resistant epilepsy surgery candidates. Demographic, psychiatric, neurological, and psychological data were recorded. Presurgical and 12-months follow-up evaluations were performed. Personality dimensions were measured by the NEO Five-Factor Inventory, Revised version (NEO-FFI-R), anxiety and depression symptoms were assessed by the Hospital Anxiety and Depression Scale (HADS: HADA-Anxiety and HADD-Depression), psychiatric evaluations were performed using the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) Axis-I disorders classification. Statistical analysis consisted of comparative tests, correlation analysis, and the stepwise multiple regression test (ANOVA). Results: A 1-year follow-up was completed by 70 out of 80 patients. Through the study, the surgical group decreased in neuroticism and increased in agreeableness. The controls increased in consciousness, and these changes were predicted by the earlier age of epilepsy onset and lesser score in HADD at the baseline. No personality changes were associated with seizure frequency. The presurgical evaluation concluded that both groups had no differences in demographic, psychiatric, or neurological variables with the only exception being for the number of seizures per month, which was higher in the surgical group. Psychiatric comorbidity in patients was associated with their higher degree of neuroticism and agreeableness at the baseline. Comparing control and surgical groups at the one-year follow-up, the agreeableness personality variable was higher in the surgical group, and as expected, HADS scores were higher in the control group, and seizure frequency was also higher in the control group. Significance: Higher agreeableness was the most relevant difference in personality dimensions in patients who underwent surgical treatment compared with the non-surgical treatment group. After surgery patients decreased in neuroticism and increased in agreeableness scores
Trayectorias laborales y asimilación ocupacional de la inmigración
En este artículo exploramos dos hipótesis relacionadas con la situación de la población inmigrante en el mercado de trabajo. La primera sostiene la idea de la asimilación ocupacional de la inmigración a través de la antigüedad en el mercado de trabajo. Esta hipótesis se apoya en el salario como indicador de la convergencia entre trabajadores autóctonos e inmigrantes. Y la segunda hipótesis sostiene la idea de la inserción estratificada en el mercado de trabajo en función de otras variables: seguridad en el empleo, cualificaciones profesionales, origen y género. Nuestro argumento central es que la asimilación se configura de forma estratificada en algunas pocas categorías profesionales y sectores de actividad, mientras que en otros persiste a lo largo de los años la brecha en las trayectorias laborales según el origen.In this article we explore two hypotheses about the conditions of immigrants in the labour market. The first one sustains that there is occupational assimilation of immigration over time. This hypothesis focuses on earnings as an indicator of convergence between native and immigrant workers. The second hypothesis argues that there is a segmented insertion in the labour market as a function of other variables different from earning: employment security, professional qualification, origin and gender. Our argument is that there is a segmented assimilation in some occupations and sectors of activity, whilst in others the origin-based gap in labour market trajectories of workers persists over the yearsFil: Martín Ardiles, Antonio. Universitat Autònoma de Barcelona; EspañaFil: Lopez Roldan, Pedro. Universitat Autònoma de Barcelona; EspañaFil: Molina, Oscar. Universitat Autònoma de Barcelona; EspañaFil: Moreno, Sara. Universitat Autònoma de Barcelona; EspañaFil: Esteban, Fernando Osvaldo. Universidad de Buenos Aires. Facultad de Ciencias Sociales. Instituto de Investigaciones "Gino Germani"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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