Nanoestructuras híbridas basadas en clústeres de nanopartículas de óxidos magnéticos y carboximetil celulosa

En el presente trabajo de investigación se reporta el desarrollo de materiales híbridos nanoestructurados basados en nanoclústeres de nanopartículas de ferritas espinela MFe2O4 (M=Fe, Co y Mn) estabilizados en una matriz polimérica de carboximetil celulosa (CMC). La preparación de estos materiales se logro en tres etapas, caracterizadas por: (1) la síntesis de las nanopartículas de ferritas espinela, vía descomposición térmica, y su dispersión en medio orgánico; (2) preparación de los nanoclústeres de estas nanopartículas a partir de emulsiones tipo aceite-en-agua, en la que se uso el bromuro de cetiltrimetil-amonio (CTAB) como tensoactivo; y (3) estabilización de los nanoclústeres en CMC, vía la adición de disoluciones acuosas de este polímero en dispersiones acuosas de los clústeres. De la caracterización realizada por TEM, utilizando técnicas como campo claro, difracción de electrones y campo oscuro anular de ángulo amplio con haz de barrido, se confirmó que las nanopartículas sintetizadas presentan una estructura cristalina acorde a la reportada para la magnetita, ferrita de cobalto y ferrita de manganeso. Estas nanopartículas presentan una morfología cuasi-esférica y tamaño promedio de entre 4 y 5 nm; siendo este último dependiente de la concentración del ácido oléico y oleilamina así como de las sales orgánicas usadas en su síntesis. Asimismo, la morfología de los clústeres es dependiente de la concentración del CTAB, ya que se encontró que a concentraciones cercanas a la concentración crítica micelar del surfactante CTAB (1 mM) es posible la obtención de clústeres de nanopartículas cuasi-esféricos en los que existe un arreglo compacto de nanopartículas de las ferritas. Más aún, la cantidad de nanoclústeres agregados y la densidad de su arreglo en la matriz de CMC cambió en función de la relación CTAB:CMC; siendo mayor la cantidad de nanoclústeres ensamblados en la matriz de CMC al incrementarse su contenido en peso de la CMC. De acuerdo con los resultados obtenidos por FTIR, este fenomeno está relacionado a las interacciones entre la cabeza polar del CTAB y los carboximetilos de la CMC. Además, se encontró que las características magnéticas de los nanoclusteres obtenidos son dependientes de efectos asociadas a interacciones núcleo-superficie en las nanopartículas, pero sobre todo a interacciones entre partículas agrupadas en los nanoclústeres. De acuerdo a las medidas magnéticas realizadas, a medida que el nanoclúster aumenta en tamaño y en densidad de nanopartículas agrupadas en él, la temperatura de bloqueo de la muestra lo hace; además de que el proceso asociado a dicho desbloqueo es dependiente del “vecindario” magnético en el cual las nanopartículas se relajan. Estos vecindarios se relacionan a nanopartículas no agrupadas en nanoclústeres y aquellos asociados a las nanopartículas que componen los nanoclústeres. En consideración de lo anterior se puede concluir que mediante el uso de nanoclústeres de nanopartículas de ferritas espinela MFe2O4 (M=Fe, Co y Mn) y del polisacárido CMC como matriz polimérica es posible la preparación de materiales híbridos nanoestructurados con aplicaciones potenciales en la medicina terapéutica y de diagnóstico. Más aún, los resultados obtenidos de este proyecto de investigación indican que, a diferencia de otros procesos reportados en la literatura, mediante el proceso aquí planteado es posible disminuir sustancialmente la concentración de agentes surfactantes que promueven el ensamblaje de los clústeres magnéticos

Study of Friction and Wear Effects in Aluminum Parts Manufactured via Single Point Incremental Forming Process Using Petroleum and Vegetable Oil-Based Lubricants

This paper focuses on studying how mineral oil, sunflower, soybean, and corn lubricants influence friction and wear effects during the manufacturing of aluminum parts via the single point incremental forming (SPIF) process. To identify how friction, surface roughness, and wear change during the SPIF of aluminum parts, Stribeck curves were plotted as a function of the SPIF process parameters such as vertical step size, wall angle, and tool tip semi-spherical diameter. Furthermore, lubricant effects on the surface of the formed parts are examined by energy dispersive spectroscopy (EDS) and scanning electron microscope (SEM) images, the Alicona optical 3D measurement system, and Fourier-transform infrared spectroscopy (FTIR). Results show that during the SPIF process of the metallic specimens, soybean and corn oils attained the highest friction, along forces, roughness, and wear values. Based on the surface roughness measurements, it can be observed that soybean oil produces the worst surface roughness finish in the direction perpendicular to the tool passes (Ra =1.45 μm) considering a vertical step size of 0.25 mm with a 5 mm tool tip diameter. These findings are confirmed through plotting SPIFed Stribeck curves for the soybean and corn oils that show small hydrodynamic span regime changes for an increasing sample step-size forming process. This article elucidates the effects caused by mineral and vegetable oils on the surface of aluminum parts produced as a function of Single Point Incremental Sheet Forming process parameters

Comparative and functional genomics of the protozoan parasite Babesia divergens highlighting the invasion and egress processes

Babesiosis is considered an emerging disease because its incidence has significantly increased in the last 30 years, providing evidence of the expanding range of this rare but potentially life-threatening zoonotic disease. Babesia divergens is a causative agent of babesiosis in humans and cattle in Europe. The recently sequenced genome of B. divergens revealed over 3,741 protein coding-genes and the 10.7-Mb high-quality draft become the first reference tool to study the genome structure of B. divergens. Now, by exploiting this sequence data and using new computational tools and assembly strategies, we have significantly improved the quality of the B. divergens genome. The new assembly shows better continuity and has a higher correspondence to B. bovis chromosomes. Moreover, we present a differential expression analysis using RNA sequencing of the two different stages of the asexual lifecycle of B. divergens: the free merozoite capable of invading erythrocytes and the intraerythrocytic parasite stage that remains within the erythrocyte until egress. Comparison of mRNA levels of both stages identified 1,441 differentially expressed genes. From these, around half were upregulated and the other half downregulated in the intraerythrocytic stage. Orthogonal validation by real-time quantitative reverse transcription PCR confirmed the differential expression. A moderately increased expression level of genes, putatively involved in the invasion and egress processes, were revealed in the intraerythrocytic stage compared with the free merozoite. On the basis of these results and in the absence of molecular models of invasion and egress for B. divergens, we have proposed the identified genes as putative molecular players in the invasion and egress processes. Our results contribute to an understanding of key parasitic strategies and pathogenesis and could be a valuable genomic resource to exploit for the design of diagnostic methods, drugs and vaccines to improve the control of babesiosis.This work was funded by grants from Ministerio de Economía y Competitividad from Spain (AGL2010-21774 and AGL2014-56193 R to EM and LMG). ES was awarded a research fellowship from Plan Estatal de Investigación Científica y Técnica y de Innovación, Ministerio de Economía y Competitividad, Spain (http://www.mineco.gob.es/portal/site/mineco/). Work in CL’s laboratory is funded by a grant from the National Institutes of Health (https://www.nih.gov/) NIH- 1R01HL140625-01. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscriptS

Haplotype analysis of the internationally distributed BRCA1 c.3331_3334delCAAG founder mutation reveals a common ancestral origin in Iberia

Background: TheBRCA1c.3331_3334delCAAG founder mutation has been reported in hereditary breast and ovarian cancer families from multiple Hispanic groups. We aimed to evaluateBRCA1c.3331_3334delCAAG haplotype diversity in cases of European, African, and Latin American ancestry. Methods: BC mutation carrier cases from Colombia (n = 32), Spain (n = 13), Portugal (n = 2), Chile (n = 10), Africa (n = 1), and Brazil (n = 2) were genotyped with the genome-wide single nucleotide polymorphism (SNP) arrays to evaluate haplotype diversity aroundBRCA1c.3331_3334delCAAG. Additional Portuguese (n = 13) and Brazilian (n = 18) BC mutation carriers were genotyped for 15 informative SNPs surroundingBRCA1. Data were phased using SHAPEIT2, and identical by descent regions were determined using BEAGLE and GERMLINE. DMLE+ was used to date the mutation in Colombia and Iberia. Results: The haplotype reconstruction revealed a shared 264.4-kb region among carriers from all six countries. The estimated mutation age was similar to 100 generations in Iberia and that it was introduced to South America early during the European colonization period. Conclusions: Our results suggest that this mutation originated in Iberia and later introduced to Colombia and South America at the time of Spanish colonization during the early 1500s. We also found that the Colombian mutation carriers had higher European ancestry, at the BRCA1 gene harboring chromosome 17, than controls, which further supported the European origin of the mutation. Understanding founder mutations in diverse populations has implications in implementing cost-effective, ancestry-informed screening

CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research

Advances in the Processing of UHMWPE-TiO2 to Manufacture Medical Prostheses via SPIF

This research focuses on developing a novel ultra high molecular weight polyethylene (UHMWPE) material reinforced with titanium dioxide (TiO 2 ) nanoparticles for producing craniofacial prostheses via an incremental sheet forming process (SPIF). First, UHMWPE-TiO 2 nanocomposite sheets were produced using incipient wetting and the compression molding process by considering different concentrations of TiO 2 nanoparticles. Then, the influence that the compression molding fabrication process has on the crystallinity and structural properties of the produced sample sheets was investigated. Experimental characterizations via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), tensile mechanical testing, and live/dead cell viability assays provided data that show an enhancement of the physical, mechanical, and biological properties. Finally, modifications on the nanocomposite material properties due to the SPIF manufacturing processes of a craniofacial prosthesis are addressed

Haplotype analysis of the internationally distributed BRCA1 c.3331_3334delCAAG founder mutation reveals a common ancestral origin in Iberia.

BackgroundThe BRCA1 c.3331_3334delCAAG founder mutation has been reported in hereditary breast and ovarian cancer families from multiple Hispanic groups. We aimed to evaluate BRCA1 c.3331_3334delCAAG haplotype diversity in cases of European, African, and Latin American ancestry.MethodsBC mutation carrier cases from Colombia (n = 32), Spain (n = 13), Portugal (n = 2), Chile (n = 10), Africa (n = 1), and Brazil (n = 2) were genotyped with the genome-wide single nucleotide polymorphism (SNP) arrays to evaluate haplotype diversity around BRCA1 c.3331_3334delCAAG. Additional Portuguese (n = 13) and Brazilian (n = 18) BC mutation carriers were genotyped for 15 informative SNPs surrounding BRCA1. Data were phased using SHAPEIT2, and identical by descent regions were determined using BEAGLE and GERMLINE. DMLE+ was used to date the mutation in Colombia and Iberia.ResultsThe haplotype reconstruction revealed a shared 264.4-kb region among carriers from all six countries. The estimated mutation age was ~ 100 generations in Iberia and that it was introduced to South America early during the European colonization period.ConclusionsOur results suggest that this mutation originated in Iberia and later introduced to Colombia and South America at the time of Spanish colonization during the early 1500s. We also found that the Colombian mutation carriers had higher European ancestry, at the BRCA1 gene harboring chromosome 17, than controls, which further supported the European origin of the mutation. Understanding founder mutations in diverse populations has implications in implementing cost-effective, ancestry-informed screening