The effect of metallicity on the abundances of molecules in protoplanetary disks

We study the influence of different metallicities on the physical, thermal, and chemical properties of protoplanetary disks, and in particular on the formation and destruction of carbon-based molecules. With the thermo-chemical code ProoDIMO we investigate the impact of lower metallicities on the radiation field, disk temperature, and the abundance of different molecules (H$_2$O, CH$_4$, CO, CO$_2$, HCN, CN, HCO$^+$ and N$_2$H$^+$). We use a fiducial disk model as a reference model and produce two models with lower metallicity. The resulting influence on different chemical species is studied by analyzing their abundance distribution throughout the disk and their vertical column density. Furthermore, the formation and destruction reactions of the chemical species are studied. The results show a relation between the metallicity of the disk and the strength of the stellar radiation field inside the disk. As the metallicity decreases the radiation field is able to penetrate deeper regions of the disk. As a result, there is a stronger radiation field overall in the disk with lower metallicity which also heats up the disk. This triggers a series of changes in the chemical formation and destruction efficiencies for different chemical species. In most cases, the available species abundances change and have greater values compared to scaled-down abundances by constant factors. Metallicity has a clear impact on the snowline of the molecules studied here as well. As metallicity decreases the snowlines are pushed further out and existing snow rings shrink in size.Comment: 19 pages, 18 figure

Regenerative capacity in the lamprey spinal cord is not altered after a repeated transection

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 14(1), (2019):e0204193, doi: 10.1371/journal.pone.0204193.The resilience of regeneration in vertebrates is not very well understood. Yet understanding if tissues can regenerate after repeated insults, and identifying limitations, is important for elucidating the underlying mechanisms of tissue plasticity. This is particularly challenging in tissues, such as the nervous system, which possess a large number of terminally differentiated cells and often exhibit limited regeneration in the first place. However, unlike mammals, which exhibit very limited regeneration of spinal cord tissues, many non-mammalian vertebrates, including lampreys, bony fishes, amphibians, and reptiles, regenerate their spinal cords and functionally recover even after a complete spinal cord transection. It is well established that lampreys undergo full functional recovery of swimming behaviors after a single spinal cord transection, which is accompanied by tissue repair at the lesion site, as well as axon and synapse regeneration. Here we begin to explore the resilience of spinal cord regeneration in lampreys after a second spinal transection (re-transection). We report that by all functional and anatomical measures tested, lampreys regenerate after spinal re-transection just as robustly as after single transections. Recovery of swimming, synapse and cytoskeletal distributions, axon regeneration, and neuronal survival were nearly identical after spinal transection or re-transection. Only minor differences in tissue repair at the lesion site were observed in re-transected spinal cords. Thus, regenerative potential in the lamprey spinal cord is largely unaffected by spinal re-transection, indicating a greater persistent regenerative potential than exists in some other highly regenerative models. These findings establish a new path for uncovering pro-regenerative targets that could be deployed in non-regenerative conditions.The authors would like to thank Dr. Cristina Roman-Vendrell and Louie Kerr, Director of the Central Microscopy Facility at the MBL, for technical support. We also thank Dr. Juan Diaz-Quiroz for helpful comments on the manuscript. EG was supported in part by an NSF REU Award (#1659604: Biological Discovery in Woods Hole at the Marine Biological Laboratory)

Transferência de oxigênio em água anóxica usando um dispositivo aerador de roda de pás em baixas revoluções

The reduction of dissolved oxygen (DO) in water is associated with the effect of climate change. The lack of oxygen in water bodies directly affects the biological species present in different shallow water bodies such as swamps and wetlands, as well as in aquaculture processes. An optimal value in the DO concentration favors the reproduction of these biological species present in both artificial and natural environments. For this, various equipment has been developed to favor the increase of DO in the water to acceptable values. However, some of these systems are expensive, energy inefficient, and noisy which generate adverse impacts in aquatic ecosystems due to perturbances in the water. This study measures the efficiency (KgO2·kWh-1) of introducing DO into the water using a paddle wheel aerator system at low RPMs destined for shallow bodies of water. Tests were performed on anoxic water samples using aerators with 6, 12, and 24 paddles at the laboratory level. By increasing the voltage (6, 9, and 12V), the RPMs applied to each device through a geared motor is also increased. The results show a higher DO transfer rate in the 1 and 5 mg of O2·L-1 range. The best configuration concerning energy consumption worked at low RPMs using the 6-paddle wheel aerator at 6V. This establishes that, in addition to the management of low revolutions, the use of a smaller number of wheels favors an increase in efficiency during the DO restoration process in shallow water bodies.La reducción de oxígeno disuelto (OD) en el agua es asociada como un efecto del cambio climático. La carencia de oxígeno en cuerpos de agua afecta directamente las especies biológicas presentes en diferentes cuerpos de agua poco profundos como pantanos y humedales, así como en procesos de acuicultura. Un valor óptimo en la concentración de OD favorece la reproducción de estas especies biológicas presentes en entornos tanto artificiales como naturales. Para esto, diversos equipos se han desarrollado para favorecer el aumento de OD en el agua a valores aceptables. Sin embargo, algunos de estos sistemas son costosos, energéticamente ineficientes y ruidosos, lo que genera impactos adversos en los ecosistemas acuáticos por perturbaciones en el agua. Este estudio mide la eficiencia (KgO2·kWh-1) de la introducción de OD en el agua mediante un sistema de aireación de rueda de aspas a bajas RPM destinado a masas de agua poco profundas. Las pruebas se realizaron en muestras de agua anóxica utilizando aireadores de 6, 12 y 24 aspas a nivel de laboratorio. Al aumentar el voltaje (6, 9 y 12V) también aumentaron las RPM aplicadas a cada dispositivo a través de un motorreductor. Los resultados muestran una tasa de transferencia de OD más alta en el rango de 1 y 5 mg de O2·L-1. La mejor configuración en relación al consumo de energía funcionó a bajas revoluciones utilizando el aireador de rueda de 6 aspas a 6V. Esto establece que, además de la gestión de bajas revoluciones, el uso de un menor número de ruedas favorece un aumento de la eficiencia durante el proceso de restauración de OD en cuerpos de agua poco profundos.A redução do oxigênio dissolvido (OD) na água está associada a um efeito das mudanças climáticas. A falta de oxigênio nos corpos d’água afeta diretamente as espécies biológicas presentes em diferentes corpos d’água rasos, como pântanos e pântanos, bem como nos processos de aquicultura. Um valor ideal na concentração de OD favorece a reprodução dessas espécies biológicas presentes em ambientes artificiais e naturais. Para isso, diversos equipamentos foram desenvolvidos para favorecer o aumento do OD na água para valores aceitáveis. No entanto, alguns desses sistemas são caros, ineficientes em energia e barulhentos, o que gera impactos adversos nos ecossistemas aquáticos devido a perturbações na água. Este estudo mede a eficiência (KgO2·kWh-1) de introdução de OD na água usando um sistema aerador de roda de pás em baixas RPMs destinado a corpos d’água rasos. Os testes foram realizados em amostras de água anóxica usando aeradores com 6, 12 e 24 pás em nível de laboratório. Ao aumentar a tensão (6, 9 e 12V), as RPMs aplicadas a cada dispositivo por meio de um motoredutor também aumentaram. Os resultados mostram uma taxa de transferência de OD mais alta na faixa de 1 e 5 mg de O2·L-1. A melhor configuração em relação ao consumo de energia trabalhou em baixas RPMs utilizando aerador de 6 rodas de pás a 6V. Isso estabelece que, além do gerenciamento de baixas revoluções, a utilização de um menor número de rodas favorece o aumento da eficiência durante o processo de restauração de OD em corpos d’água rasos

Production and purification of immunologically active core protein p24 from HIV-1 fused to ricin toxin B subunit in E. coli

<p>Abstract</p> <p>Background</p> <p>Gag protein from HIV-1 is a polyprotein of 55 kDa, which, during viral maturation, is cleaved to release matrix p17, core p24 and nucleocapsid proteins. The p24 antigen contains epitopes that prime helper CD4 T-cells, which have been demonstrated to be protective and it can elicit lymphocyte proliferation. Thus, p24 is likely to be an integral part of any multicomponent HIV vaccine. The availability of an optimal adjuvant and carrier to enhance antiviral responses may accelerate the development of a vaccine candidate against HIV. The aim of this study was to investigate the adjuvant-carrier properties of the B ricin subunit (RTB) when fused to p24.</p> <p>Results</p> <p>A fusion between ricin toxin B subunit and p24 HIV (RTB/p24) was expressed in <it>E. coli</it>. Affinity chromatography was used for purification of p24 alone and RTB/p24 from cytosolic fractions. Biological activity of RTB/p24 was determined by ELISA and affinity chromatography using the artificial receptor glycoprotein asialofetuin. Both assays have demonstrated that RTB/p24 is able to interact with complex sugars, suggesting that the chimeric protein retains lectin activity. Also, RTB/p24 was demonstrated to be immunologically active in mice. Two weeks after intraperitoneal inoculation with RTB/p24 without an adjuvant, a strong anti-p24 immune response was detected. The levels of the antibodies were comparable to those found in mice immunized with p24 alone in the presence of Freund adjuvant. RTB/p24 inoculated intranasally in mice, also elicited significant immune responses to p24, although the response was not as strong as that obtained in mice immunized with p24 in the presence of the mucosal adjuvant cholera toxin.</p> <p>Conclusion</p> <p>In this work, we report the expression in <it>E. coli </it>of HIV-1 p24 fused to the subunit B of ricin toxin. The high levels of antibodies obtained after intranasal and intraperitoneal immunization of mice demonstrate the adjuvant-carrier properties of RTB when conjugated to an HIV structural protein. This is the first report in which a eukaryotic toxin produced in <it>E. coli </it>is employed as an adjuvant to elicit immune responses to p24 HIV core antigen.</p

Economic impact of introducing TYRX amongst patients with heart failure and reduced ejection fraction undergoing implanted cardiac device procedures: a retrospective model based cost analysis

BACKGROUND AND AIMS: Infection is a serious and expensive complication of Cardiac Implantable Electronic Device (CIED) procedures. A retrospective based cost analysis was performed to estimate Trust level savings of using the TYRX antibacterial envelope as a primary prevention measure against infection in a tertiary referral centre in South London, UK. METHODS: A retrospective cohort of heart failure patients with reduced ejection fraction undergoing Implantable Cardioverter Defibrillator (ICD) or Cardiac Resynchronization Therapy (CRT) procedures were evaluated. Decision-analytic modelling was performed to determine economic savings of using the envelope during CIED procedure vs CIED procedure alone. RESULTS: Over a 12 month follow-up period following CIED procedure, the observed infection rate was 3.14% (n = 5/159). The average cost of a CIED infection inpatient admission was £41,820 and, further to economic analysis, the additional costs attributable to infection was calculated at £62,213.94. A cost saving of £624 per patient by using TYRX during CIED procedure as a primary preventative measure against infection was estimated. CONCLUSIONS: TYRX would be a cost-saving treatment option amongst heart failure patients undergoing ICD and CRT device procedures based on analysis in the local geographical area of South London. If upscaled to the UK population, we estimate potential cost savings for the National Health Service (NHS)

Lattice Boltzmann simulation of flow past a spherical/non-spherical particle in a wide range of Reynolds number

Lattice Boltzmann method was used to predict the fluid-particle interaction for arbitrary shaped particles. In order to validate the reliability of the present approach, simulation of flow past a single stationary spherical, cylindrical or cubic particle is conducted in a wide range of Reynolds number (0.1 < Rep < 3000). The results indicate that the drag coefficient is closely related to the particle shape, especially at high Reynolds numbers. The voxel resolution of spherical particle plays a key role in accurately predicting the drag coefficient at high Reynolds numbers. For non-spherical particles, the drag coefficient is more influenced by the particle morphology at moderate or high Reynolds numbers than at low ones. The inclination angle has an important impact on the pressure drag force due to the change of projected area. The simulated drag coefficient agrees well with the experimental data or empirical correlation for both spherical and non-spherical particles

Acumulación de Ag, Cu y Ni en sedimentos en una cuenca semiárida como sub-producto de la mina de oro El Triunfo, Baja California Sur, México

The dispersal of Ag, Cu, and Ni in mine wastes (tailings and ash) was studied from the source of an abandoned gold mine at El Triunfo (Baja California Sur, Mexico) to the adjacent coast of the Pacific Ocean. The highest contamination levels of the studied elements were measured in one sample of the tailings (Ag: 247 mg kg-1; Cu: 1660 mg kg-1; Ni: 111 mg kg-1). Horizontal and vertical distributions of these elements were obtained from the analysis of surface sediments, tailings, a test pit, a sediment core, and dunes. The background levels of these elements were estimated from independent methods. Then, these regional background level calculations were used to determine the normalised enrichment factors (NEFs). Relatively high NEF values (averages of Ag, Cu, and Ni were 24.0, 3.0, and 1.4, respectively) indicated that the area close to the mine waste zone (up to about 18 km from the source area) was moderately to severely polluted. Moderate to null pollution (average NEFs of Ag, Cu, and Ni were 7, 2 and 1, respectively) was interpreted for the area at about 18-49 km from the mine waste zone. Vertical distributions of the elements in sediments of the overbank, the test pit in the mine zone, and the sediment core (at the discharge of the main arroyo Hondo–Las Gallinas–El Carrizal), also revealed enrichment of Ag, Cu, and Ni relative to the surface sediments. This study indicated that historic and contemporary contamination continues to impact the fluvial environment.Se estudió la dispersión de Ag, Cu, y Ni, en desechos mineros (jales y cenizas) desde su origen en la mina de oro abandonada de El Triunfo (Baja California Sur, México) hasta su desembocadura en la costa adyacente al Océano Pacífico. Los mayores niveles de la contaminación de los elementos estudiados se presentan en los jales (Ag: 247 mg kg-1; Cu: 1660 mg kg-1; Ni: 111 mg kg-1). Se obtuvieron distribuciones horizontales y verticales de estos elementos a partir de los análisis de sedimentos superficiales, de deterun jale, de un pozo de ensayo, de un testigo y en las dunas adyacentes a la desembocadura del arroyo. Los niveles de fondo fueron calculados considerando varios métodos independientes. Luego, con estos cálculos de niveles de fondo se determinaron los Factores de Enriquecimiento Normalizados (NEFs). Los valores relativamente altos de NEF (promedios de Ag, Cu and Ni de 24.0, 3.0 y 1.4, respectivamente) indicaron que el área situada cerca de la zona minera (aproximadamente 18 km de los desechos mineros abandonados) se encuentra de moderada a severamente contaminada. Una contaminación moderada a nula (NEFs promedio de Ag, Cu y Ni: 7, 2 y 1, respectivamente) fue determinada en el área comprendida entre los 18 y los 49 km medidos desde el distrito minero. Las distribuciones verticales de los elementos en los sedimentos de los jales y el pozo de ensayo en la zona minera, así como en el testigo analizado en la desembocadura del arroyo principal (Arroyo Hondo – Las Gallinas – El Carrizal), muestran mayor enriquecimiento de Ag, Cu y Ni, que los sedimentos superficiales adyacentes. Este estudio indica que la contaminación histórica y contemporánea está impactando el ambiente fluvial

Dynamics of water condensation over arrays of hydrophilic patches

We report experimental results of drop-wise condensation on a wettability patterned substrate. It consists of a 2-d array of hydrophilic patches/spots on a macroscopically hydrophobic surface. We show that in this kind of system, there is not a relevant humidity sink, but the scale and the closeness of the different patches/spots affect the mechanisms which are important during the experiment. These results may provide clues to obtain higher dew yields in arid or semi-arid regions as a way to obtain potable water