Nanoparticle-based lateral flow biosensors

Lateral flow biosensors (LFBs) are paper-based devices which permit the performance of low-cost and fast diagnostics with good robustness, specificity, sensitivity and low limits of detection. The use of nanoparticles (NPs) as labels play an important role in the design and fabrication of a lateral flow strip (LFS). The choice of NPs and the corresponding detection method directly affect the performance of these devices. This review discusses aspects related to the application of different nanomaterials (e.g. gold nanoparticles, carbon nanotubes, quantum dots, up-converting phosphor technologies, and latex beads, between others) in LFBs. Moreover, different detection methods (colorimetric, fluorescent, electrochemical, magnetic, etc.) and signal enhancement strategies (affording secondary reactions or modifying the architecture of the LFS) as well as the use of devices such as smartphones to mediate the response of LFSs will be analyzed

A Qualitative assessment of 50 years of rescue archaeology in Sevilla (1944 - 1998)

Los estudios arqueológicos en la ciudad de Sevilla gozan de una importante tradición que puede extenderse al menos durante los últimos cien años. Sin embargo, a efectos del presente estudio hemos establecido una delimitación temporal más reducida correspondiente con los últimos cincuenta años, atendiendo a los criterios de intencionalidad científica y registro completo que inaugura Collantes de Terán en la “Cuesta del Rosario” (1944). Asimismo, se ha concentrado nuestra atención en aquellas intervenciones efectuadas en el casco y arrabales históricos de la ciudad, obviando la Cartuja de Santa María de las Cuevas, la Buhayra o el Cortijo de Miraflores. En este marco de actuación nuestro objetivo es efectuar un balance de los resultados obtenidos haciendo una revisión crítica de los análisis anteriores y avanzando en nuevas líneas de trabajo.Archaeological studies in the city of Seville have been developed at least during the last century. However, the time delimitation of this work is more reduced, corresponding with the last fifty years, due to scientist criteria and complex registry make by Collantes de Terán in the “Cuesta del Rosario” (1944). In the same way, our attention is focused in those interventions make in the historic center and suburbs, and not in distant ones. The objective of this work is to make an assessment of results by a critic revision of the previous analysis and to advance in new research lines

Is there gender bias when creative directors judge advertising? Name cue effect in ad evaluation

A lack of women in creative departments has been documented in previous research. These departments are seen as a male fraternity subculture in advertising agencies, where women experience many difficulties in their career progress. One of these drawbacks is gender bias in the selection of ideas' process. Male creative directors are believed to promote ideas created by men within a homosocial environment. This female perception, that emerged from previous qualitative research, is studied experimentally for the first time. Almost 90 advertising creative directors and higher level positions, assessed ads created by students in an advertising university course. In the current study we explore the effects of ad gender authorship. Results revealed an absence of gender bias based on ad name cues, neither the gender of the ad creators nor the creatives affected the evaluations. The findings are discussed and future research is proposed

Electrochemical detection of plant virus using gold nanoparticle-modified electrodes

Tristeza is one of the destructive diseases of citrus causing by citrus tristeza virus (CTV). Historically, CTV has been associated with serious outbreaks of quick decline of citrus, therefore CTV monitoring is important aspect for avoiding such re-emerging epidemics, which would threat citrus production through the world. In this context, we have designed for the first time a label-free impedimetric biosensor for the detection of nucleic acid of CTV. The sensing platform based on a screen-printed carbon electrode (SPCE) was modified by electrodeposited gold nanoparticles (AuNPs), which allowed to efficiently immobilizing thiolated ssDNA probes as well to enhance the electrode conductivity. The growth of AuNPs was optimized and characterized using scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). We investigated the behavior of thiolated ssDNA probe layer and its hybridization with target DNA onto AuNP surfaces by EIS measurements in Fe(CN₆)⁴⁻)/Fe(CN₆)³⁻ red-ox system. The main sensor design aspects such as AuNPs size, probe DNA concentration and immobilization time together with DNA hybridization time were optimized so as to achieve the best performance. Impedance values of DNA hybridization increased with Citrus tristeza-related synthetic DNA concentration, showing a logarithmic relation in the range of 0.1-10 μM. The results also indicate that the biosensor was able to selectively detect CTV nucleic acids in the presence of other non-specific DNAs. Moreover, we have demonstrated the good performance of the system in a real plant sample matrix. In addition, the sensor reproducibility enhanced after the hybridization onto MCH/poly (AT) thiolated DNA probes which was confirmed by intra- and inter-day variability assays

Use of plastic scrap in asphalt mixtures added by dry method as a partial substitute for bitumen

In recent decades, the generation of plastic waste has increased substantially worldwide, with the result that more of such waste is introduced into the environment. Currently, most polymers (polyethylene terephthalate, polyethylene, polyvinyl chloride, and others) are recycled. However, some are rejected for recycling in the primary separation processes due to their physical condition, contamination, or size. These materials are called plastic scrap. In this research, the use of plastic scrap added by dry method was evaluated as a replacement for bitumen in asphalt mixtures. Two sizes of plastic scrap, coarse and fine, were considered. An AC16S semi-dense mixture was designed for this purpose, with a 10% reduction in binder, and 10% and 20% of plastic scrap binder was added in coarse and fine sizes. The results obtained in the Marshall stability and flow test showed reduced moisture damage, greater indirect tensile strength, higher air void content, and a 2% decrease in the conserved tensile strength ratio while the same usage field as the conventional mixture was maintained. Meanwhile, significant decreases in plastic deformations, as compared to traditional values, were obtained from resilient modulus and rutting tests

Signal enhancement on gold nanoparticle-based lateral flow tests using cellulose nanofibers

Lateral flow paper-based biosensors merge as powerful tools in point-of-care diagnostics since they are cheap, portable, robust, selective, fast and easy to use. However, the sensitivity of this type of biosensors is not always as high as required, often not permitting a clear quantification. To improve the colorimetric response of standard lateral flow strips (LFs), we have applied a new enhancement strategy that increases the sensitivity of LFs based on the use of cellulose nanofibers (CNF). CNF penetrate inside the pores of LFs nitrocellulose paper, compacting the pore size only in the test line, particularly near the surface of the strip. This modification retains the bioreceptors (antibodies) close to the surface of the strips, and thus further increasing the density of selectively attached gold nanoparticles (AuNPs) in the top part of the membrane, in the test line area, only when the sample is positive. This effect boosts in average a 36.6% the sensitivity of the LFs. The optical measurements of the LFs were carried out with a mobile phone camera whose imaging resolution was improved by attaching microscopic lens on the camera objective. The characterization of CNF into paper and their effect was analyzed using atomic force microscope (AFM) and scanning electron microscope (SEM) imaging techniques

Iridium oxide (IV) nanoparticle-based lateral flow immunoassay

Lateral flow biosensors are paper-based devices that allow the detection of different types of analytes with quickness, robustness and selectivity, without leaving behind paper sensors benefits as low-cost, recyclability and sustainability. Nanomaterials have been widely reported in lateral flow biosensors, offering new sensing strategies based on optical or electrical detection techniques. Looking for other advantageous nanomaterials, we propose for the first time the use of iridium oxide (IV) nanoparticles in lateral flow assays for the detection of human immunoglobulin as a model protein. These nanoparticles can be easily prepared and conjugated with biomarkers. Their dark blue color gives a high contrast against the white background of the strips being in this way excellent labels

Conducto onfalomesenterico permeable en adulto. Presentación de un caso clínico.

Introducción. En el embrión humano la  conexión entre el intestino y el saco vitelino, se comienza a obliterar por su crecimiento pero comunicados por el conducto onfalomesenterico que  finalmente se cierra. En el caso clínico que se presenta  permanece el conducto permeable sin obliterarse. Los autores nos proponemos presentar un paciente adulto con conducto onfalomesenterico persistente con manifestaciones clínicas de fistula entero cutánea. Presentación.  Masculino, 40 años de edad,  piel blanca, consulta por presentar desde hace  cuatro  años salida de líquido  a través del ombligo  de aspecto amarillo intenso y se acompaña de fetidez, a estos síntomas se asocia molestias  peri umbilicales,  se aprecia la salida de contenido amarillo claro con fetidez, resto del  examen físico normal. Los  resultado imagenlógico nos permite presumir la presencia de un divertículo de Meckel fistulizado al ombligo.  Durante la cirugía  se  identifica conducto de intestino delgado  que comunica  con ombligo y se encuentra torcido sobre su eje,  se hace   resección y se restablece la continuidad intestinal.  El postoperatorio trascurrió sin complicaciones. Discusión. Se encontró un conducto onfalomesenterico persistente,  la torsión que se constató en el trayecto fistuloso debido a la longitud del divertículo, justifica la intermitencia de  la salida del contenido intestinal. El tratamiento quirúrgico es la conducta a seguir. Conclusiones. La presencia de una fístula entero cutánea al ombligo sin antecedentes de intervención quirúrgica, obliga a tener presente esta enfermedad  congénita

Simple isophthalamides/dipicolineamides as active transmembrane anion transporters

Eight N,N´-diarylisophthalamide/dipicolineamide derivatives have been synthesised and fully characterised, both in solution and in the solid state. The transmembrane anion transport properties of these compounds have been studied by chloride-selective electrode and fluorescence experiments. The substitution pattern of the aromatic moieties determines the transport properties of these systems, with those containing electron-withdrawing groups in their structures being the most active ones of the series.Consejería de Educación de la Junta de Castilla y León (project BU075G19

A needle in a haystack: A new metabarcoding approach to survey diversity at the species level of Arcellinida (Amoebozoa: Tubulinea)

Environmental DNA-based diversity studies have increased in popularity with the development of high throughput sequencing technologies. This permits the potential simultaneous retrieval of vast amounts of molecular data from many different organisms and species, thus contributing to a wide range of biological disciplines. Environmental DNA protocols designed for protists often focused on the highly conserved small subunit of the ribosome gene, that does not permit species-level assignments. On the other hand, eDNA protocols aiming at species-level assignments allow a fine level ecological resolution and reproducible results. These protocols are currently applied to organisms living in marine and shallow lotic freshwater ecosystems, often in a bioindication purpose. Therefore, in this study, we present a species-level eDNA protocol designed to explore diversity of Arcellinida (Amoebozoa: Tubulinea) testate amoebae taxa that is based on mitochondrial cytochrome oxidase subunit I (COI). These organisms are widespread in lentic water bodies and soil ecosystems. We applied this protocol to 42 samples from peatlands, estuaries and soil environments, recovering all the infraorders in Glutinoconcha (with COI data), except for Hyalospheniformes. Our results revealed an unsuspected diversity in morphologically homogeneous groups such as Cylindrothecina, Excentrostoma or Sphaerothecina. With this protocol we expect to revolutionize the design of modern distributional Arcellinida surveys. Our approach involves a rapid and cost-effective analysis of testate amoeba diversity living in contrasted ecosystems. Therefore, the order Arcellinida has the potential to be established as a model group for a wide range of theoretical and applied studie