Anticancer Activities of Meroterpenoids Isolated from the Brown Alga Cystoseira usneoides against the Human Colon Cancer Cells HT-29

Colorectal cancer (CRC) is one of the most common types of cancers and a leading cause of cancer death worldwide. The current treatment for CRC mainly involves surgery, radiotherapy, and chemotherapy. However, due to the side effects and the emergence of drug resistance, the search for new anticancer agents, pharmacologically safe and effective, is needed. In the present study, we have investigated the anticancer effects of eight algal meroterpenoids (AMTs, 1-8) isolated from the brown seaweed Cystoseira usneoides and their underlying mechanisms of action using HT-29, a highly metastatic human colon cancer cell line. All the tested meroterpenoids inhibited the growth of HT-29 malignant cells and were less toxic towards non-cancer colon cells, with the AMTs 1 and 5 exhibiting selectivity indexes of 5.26 and 5.23, respectively. Treatment of HT-29 cells with the AMTs 1, 2, 3, 4, 5, and 7 induced cell cycle arrest in G2/M phase and, in some instances, apoptosis (compounds 2, 3, and 5). Compounds 1-8 also exhibited significant inhibitory effects on the migration and/or invasion of colon cancer cells. Mechanistic analysis demonstrated that the AMTs 1, 2, 5, 6, 7, and 8 reduced phosphorylation levels of extracellular signal-regulated kinase (ERK) and the AMTs 2, 3, 4, 5, 7, and 8 decreased phosphorylation of c-JUN N-terminal kinase (JNK). Moreover, the AMTs 1, 2, 3, 4, 7, and 8 inhibited phosphorylation levels of protein kinase B (AKT) in colon carcinoma cells. These results provide new insights into the mechanisms and functions of the meroterpenoids of C. usneoides, which exhibit an anticancer effect on HT-29 colon cancer cells by inducing cell cycle arrest and apoptosis via the downregulation of ERK/JNK/AKT signaling pathways

Saving assessment using the PERS in solar power towers

The improvement of the solar power tower using solar salt is one of the main goals of researchers. Any method or invention to improve the efficiency of this technology contributes to promote the renewable energies. The use of a Potential Energy Recovery System (PERS) in two different solar power tower plants of 20 and 100 MW has been analysed. The PERS is formed, at least, by one turbine, located at the hot salt pipe coming from the receiver. The turbine is engaged to the shaft of the feed pump, which raises the heat transfer fluid from the cold tank to the receiver. It reduces the parasitic power consumption of the plant, and increases its global efficiency. Different PERS configurations have been modelled. Based on an energetic and economic analysis, the optimal configuration is a geometrical similar turbine of three times the volume flow rate of one feed pump. The PERS has been proven to be a cost reductive and clean tool. For a 100 MW power plant of 30-year lifetime the investment cost is 1.26 M$and the annual cash flow is 0.89 M$, while for a plant of 20 MW these values are 0.26 M$and 0.19 M$, respectively.The financial support from CDTI and S2m Solutions for the MOSARELA Project (Molten salt receiver lab), whose reference is IDI-20120128. Finally, the financial support of the ENE2012-34255 Project is also acknowledged

Thermo-mechanical modelling of solar central receivers: effect of incident solar flux resolution

The most important constraint for central receiver design is to keep the intercepting solar flux within the tube mechanical safety limits. An error in the heliostat aiming strategy or an inaccurate estimation of the tube temperature can produce overheating of the tubes, putting at risk the power plant operation. Therefore, the development of thermo-mechanical models to predict the incident solar flux, the temperature and the thermal stresses is mandatory. The large number of tubes in the receivers makes a detailed simulation computationally expensive, and simplifications are usually done. These simplifications consist on selecting a representative tube in each panel of the receiver and reducing the spatial resolution of the incident radiation to a scale equal to one panel size. This "coarse grid model" simulation can be used with confidence to obtain the solar tower yield production with an error lower than 2.5%. However, the small resolution of this model results in errors in the wall temperature and the thermal stresses estimation, and hence in the aiming strategy selection. In this study a 'fine grid model", whose cells have a size equal to the tube pitch (distance between centres of the tubes) width in the receiver, has been developed for an accurate estimation of the tube wall temperature. Using this fine grid model the temperature and the thermal stress profiles in each tube, for a given panel of the receiver, can be indirectly obtained without assuming that all the tubes of the panel have the same temperature profiles. Therefore, for modelling receiver, the fine grid model is required to determine with more accuracy the maximum tube stress and the aiming strategy, especially in the real situation of a highly non-uniform solar flux onto the receiver

The oldest record of Hemiauchenia Gervais and Ameghino (Mammalia, Cetartiodactyla) in South America: Comments about its paleobiogeographic and stratigraphic implications

The South American camelids belong to the Tribe Lamini; this Tribe originated in North America and arrived in South America during the ‘‘Great American Biotic Interchange’’. The goals of this paper are: (i) to describe the specimen MAM-70, the oldest record of Hemiauchenia Gervais and Ameghino in South America; (ii) to analyze this specimen from a stratigraphic point of view; (iii) to update the distribution and stratigraphic ranges of Lamini in South America; and (iv) to discuss its dispersal pattern to South America. The finding of Hemiauchenia sp. in late Pliocene Chapadmalalan sediments cropping out at the city of Olavarrı´a (Buenos Aires Province, Argentina) represents the oldest record of a Lamini taxon in South America. This finding refutes the hypotheses that consider the genus Lama as the first North American immigrant and those considering that Hemiauchenia and Palaeolama arrived in South America after the closure of the Central America land bridge, during the early–middle Pleistocene. In turn, this specimen corroborates the hypothesis of the dispersal of Lamini from North America to South America, which considered that Palaeolama dispersed after Hemiauchenia, in a later and isolated event. In addition, this finding suggests the possibility that a form closely related to the North American Hemiauchenia macrocephala could have dispersed to South America during the Pliocene, thus originating the South American forms of Hemiauchenia and Lama.Facultad de Ciencias Naturales y Muse

Comparison of simplified heat transfer models and CFD simulations for molten salt external receiver

In the absence of experimental correlations of the solar external receiver performance, it is particularly necessary to develop thermal models to optimize the receiver operating modes and to properly design such equipments. Since CFD models require an enormous computational cost to simulate a receiver, two simplified bi-dimensional implicit-scheme models have been developed. Both models consider axial and circumferential variations on the heat flux absorbed by the tubes and on the wall temperature. One assumes homogeneous surface boundary condition and the other assumes homogeneous surface heat flux at the discretized tube wall. The effects of mass flow rate, and wind velocity on the receiver performance have been analysed considering steady state operation. The results have been compared with a simulation carried out with ANSYS Fluent. Both simplified models are able to predict the heat fluxes, the salt and the tube wall temperature with a deviation lower than 6% compared to CFD simulations. The analysis of the developed models has been also compared with a model usually employed that does not consider variable circumferential temperature. The results show that keeping constant the circumferential tube wall temperature leads to lower wall temperature, underestimating the film temperature, the thermal stress and the salt decomposition.The authors would like to thank the financial support provided by CDTI and S2m Solutions for the project MOSARELA (Molten Salt Receiver-Lab) whose reference number is IDI-20120128, and for the project ENE2012-34255 sponsored by the Spanish government.Publicad

Meroterpenoids from the Brown Alga Cystoseira usneoides as Potential Anti-Inflammatory and Lung Anticancer Agents

The anti-inflammatory and anticancer properties of eight meroterpenoids isolated from the brown seaweed Cystoseira usneoides have been evaluated. The algal meroterpenoids (AMTs) 1-8 were tested for their inhibitory effects on the production of the pro-inflammatory cytokines tumor necrosis factor (TNF-alpha), interleukin-6 (IL-6), and interleukin-1 beta (IL-1 beta), and the expression of cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) in LPS-stimulated THP-1 human macrophages. The anticancer effects were assessed by cytotoxicity assays against human lung adenocarcinoma A549 cells and normal lung fibroblastic MRC-5 cells, together with flow cytometry analysis of the effects of these AMTs on different phases of the cell cycle. The AMTs 1-8 significantly reduced the production of TNF-alpha, IL-6, and IL-1 beta, and suppressed the COX-2 and iNOS expression, in LPS-stimulated cells (p < 0.05). The AMTs 1-8 displayed higher cytotoxic activities against A549 cancer cells than against MRC-5 normal lung cells. Cell cycle analyses indicated that most of the AMTs caused the arrest of A549 cells at the G2/M and S phases. The AMTs 2 and 5 stand out by combining significant anti-inflammatory and anticancer activities, while 3 and 4 showed interesting selective anticancer effects. These findings suggest that the AMTs produced by C. usneoides may have therapeutic potential in inflammatory diseases and lung cancer

Thermodynamic and economic assessment of a new generation of subcritical and supercritical solar power towers

The feasibility of using more efficient Rankine power blocks in solar power towers (SPTs) with molten salt as the heat transfer fluid has been studied as a method for increasing the global efficiency of these power plants. The temperature and pressure of the main steam and the reheating pressure affect the temperature of the molten salt in the receiver; for temperature increase decreasing the receiver efficiency and increasing the power block efficiency. Therefore, a detailed study of these SPTs has been conducted to determine whether the proposed changes increase the global efficiency of the SPTs. A total of eight different subcritical and supercritical SPTs have been investigated. To set the most important cost of the SPT, the same heliostat field has been used. The receiver geometry has been optimised for each SPT to maximise the heliostat-receiver efficiency, fulfilling the material limitations. It has been observed that the pressure at the inlet of the turbine increases the SPT efficiency even more than the temperature. However, special attention has to be paid to the reheating pressure, which is the most influential factor on the SPT efficiency. A high reheating pressure considerably decreases the SPT efficiency. Therefore, the best efficiencies have been obtained for the supercritical SPTs with a low reheating pressure and high temperature. It is closely followed by subcritical SPTs at high pressure and temperature. The investment cost of the different SPTs also increases with the pressure and the temperature of the PB, with subcritical SPTs being less expensive than supercritical SPTs. However, the cost increase is balanced by the increase in the efficiency. The same cost per kWe is found in subcritical SPTs working at 16 MPa and in supercritical SPTs with low reheating pressure

District cooling network connected to a solar power tower

During the operation of solar power towers there are occasions, commonly in the summer season, where some of the heliostats have to stop focussing on the central receiver, located at the top of the tower, because the maximum thermal power that the receiver can withstand has been reached. The highest cooling demand takes place at these same occasions. In the present paper, the exceeding heliostats are focused to a second receiver, using the extra heat as a source of absorption chillers. The chilled water is used to cool buildings or offices, using a district cooling network, reducing greatly the electricity usage. In this work we have analysed the case of a circular field of heliostats focussing at an external receiver of 120 MW of thermal power. The thermal power of the exceeding heliostats is able to supply steam to eight absorption chillers that produce cold water for a population of more that 90000 people via a network of more than the 50 km. The economical analysis shows that the district cooling system is profitable and an advantageous option for the consumers, that can obtain up to 75% savings on their electricity bills.The authors would like to thank the financial support by the Spanish Ministry of Economy and Competitiveness under Project No. ENE2012-34255 as well as the MOSARELA (Molten salt receiver lab) project, IDI-20120128, supported by CDTI and S2m Solutions.Publicad

Mecanismos pedagógicos para la resolución de conflictos convivenciales en la IED San José de Barranquilla

In this research, which is focused on implementing educational mechanisms as a means of conflict resolution is raised in a work of consultations and analysis at different previous work, done in the school IED San Jose city of Barranquilla by the participants of this project. Where whose objective is based on identifying the different types of conflicts within the students' area. Taking into account the different degrees to which they corresponded, in order to allow us to implement solutions, strategies that would lead to the resolution of conflicts, these include the areas of students, teachers and managers. As a methodology we made use of surveys which were directed to the students and interviews with the teachers, directors and psycho-counselor of the present institution where they supported our research. This was structured with different approaches, questions that allow us to answer such sensitive issues that are presented in the student community. For example, recognizing that it motivated the presence of a conflictive action within the students, in addition to the ways of generating conflict to understand. Understanding that a tool such as the survey will allow the student to freely express their thought or situation, it was decided to do it in this way, rather than in a kind of interview. In the case of teachers, managers and psycho-counselors, the exercise carried out was by means of an interview, where in a simple way we could get to know from their point of view the types of conflict but especially the way in which they applied the solution according to to what is established in the normative part of the institution. All this result will generate a number of information, which led us to understand the situation that occurs within the institution. Which is nothing more than the one presented in many institutions in our region. With all this material it is possible to direct actions that lead to a resolution of conflicts or reconciliation, sometimes even preventing before they occur. Their identification allowed the management and teachers to take much more effective actions or strategies to solve or avoid it. Within our research, it was possible to understand the form of violence or harassment that occurs in many students, which is sometimes generated by the family part. That is, the participation of the parent or guardian is a fundamental element for a better response to the work that is presented by the institution with respect to this issue, it is not an exclusive subject of the student area but of a joint work of several parts. That is why the completion of this research yielded information of great interest to recognize the situation and also take action in the institutions in order to focus on ending these types of circumstances among students, referring to the conflict. Emphasizing the importance of reconciliation between the parties as a primary element in the students' environment.En la presente investigación, la cual está enfocada en la implementación de mecanismos pedagógicos como mecanismo de resolución de conflictos, está planteado en una labor de consultas y análisis a diferentes trabajos previamente realizados, hechos en la institución educativa IED San José de la ciudad de Barranquilla por parte de los participantes de este proyecto. En donde cuyo objetivo se basa en lograr identificar los diferentes tipos de conflictos dentro del área de los estudiantes. Teniendo en cuenta los distintos grados a que correspondían, con el fin de que nos permitiera implementar soluciones, estrategias que conllevara a la resolución de los conflictos, estos incluyen las áreas de estudiante, profesores y directivos. Como metodología hicimos uso de encuestas las cuales fueron dirigidos a los estudiantes y de entrevistas hacia los docentes, directivos y psico-orientadora de la presente institución en donde fueron apoyo a nuestra investigación. Esta fue estructurada con diferentes enfoques, preguntas que nos permitiera dar respuesta de temas tan sensibles que se presentaban en la comunidad estudiantil. Por ejemplo, el reconocer que motivaba la presencia de una acción conflictiva dentro del estudiantes, además de entender las diferentes formas de generar conflicto. Entendiendo que una herramienta como la encuesta permitiría que el alumno pudiera expresar de manera libre su pensamiento o situación, se optó por hacerlo de esta forma, que hacerlo en especie de entrevista. Para el caso de los docentes, directivos y psico-orientadores el ejercicio realizado fue por medio de entrevista, donde de una manera sencilla lográramos conocer desde su punto de vista los tipos de conflicto, pero en especial la manera en que ellos aplicaran la solución de acuerdo a lo establecido en la parte normativa de la institución. Todo este resultado permitió generar un sin número de información, que nos llevó a entender la situación que se presenta dentro de la institución. Que no es más que la presentada en muchas instituciones de la región. Con todo este material se es posible encaminar acciones que conlleve a una solución de conflictos o reconciliación, hasta en ocasiones prevenir antes de que ocurran. La identificación de los mismos permitirá a la parte directiva y docentes tomar acciones o estrategias mucho más efectivas para solucionarlo o evitarlo. Dentro de nuestra investigación se logró entender la forma violenta o de acoso que se presentan en muchos estudiantes, que en ocasiones vienen generadas por la parte familiar. Es decir, la participación del padre de familia o acudiente es elemento fundamental para una mejor respuesta a la labor que se presente por parte de la institución con respecto a este tema, no es un tema exclusivo del área estudiantil sino de un trabajo mancomunado de varias partes. Es por ello, que la realización de esta investigación arrojo información de gran interés para reconocer la situación y así mismo tomar acciones en las instituciones con el fin de enfocarnos a dar por terminado este tipo de circunstancias entre los alumnos, refiriéndonos al conflicto. Enfatizando la importancia de la reconciliación entre las partes como elemento primordial en el ambiente de los estudiantes