Hexavalent Chromium Removal by a Paecilomyces sp. Fungal Strain Isolated from Environment

A resistant and capable fungal strain in removing hexavalent chromium was isolated from an environment near of Chemical Science Faculty, located in the city of San Luis Potosí, Mexico. The strain was identified as Paecilomyces sp., by macro- and microscopic characteristics. Strain resistance of the strain to high Cr (VI) concentrations and its ability to reduce chromium were studied. When it was incubated in minimal medium with glucose, another inexpensive commercial carbon source like unrefined and brown sugar or glycerol, in the presence of 50 mg/L of Cr (VI), the strain caused complete disappearance of Cr (VI), with the concomitant production of Cr (III) in the growth medium after 7 days of incubation, at 28°C, pH 4.0, 100 rpm, and an inoculum of 38 mg of dry weight. Decrease of Cr (VI) levels from industrial wastes was also induced by Paecilomyces biomass. These results indicate that reducing capacity of chromate resistant filamentous fungus Cr (VI) could be useful for the removal of Cr (VI) pollution

Bases ecológicas para el manejo y conservación de los recursos pesqueros: experiencia de México

La presente contribución resume la información de la conferencia magistral -del mismo nombre-, la cual fue ofrecida como parte de las actividades del Primer Simposio de Ciencias del Mar de El Salvador, realizado en San Salvador del 09 al 10 de octubre de 2017, y organizado por el Instituto de Ciencias del Mar y Limnología (ICMARES) de la Universidad de El Salvador. De este modo los comentarios que se vierten representan la opinión personal del autor y su experiencia en el área de la taxonomía y conservación de peces, tema que se plasma en los párrafos subsecuentes

Representaciones sociales del empleo y desempleo de población del País Vasco

Con la base teórico metodológica de las representaciones sociales (RS) se analizan los conceptos de empleo y desempleo en dos grupos poblacionales del País Vasco: jóvenes de 20 y menos años y adultos mayores de 21 años y más. Se utiliza la técnica asociativa de listados libres para conocer el contenido y estructura de las RS, así como la identificación del núcleo central y los elementos periféricos. Para los participantes el empleo es una ocupación que implica acceso al dinero, favorece la satisfacción de necesidades, genera felicidad. Para los mayores de 21 años es un medio para obtener dignidad, realización y futuro. El desempleo implica la falta de dinero, crisis y pobreza, genera desesperanza, depresión y agobio. Para los mayores de 21 años genera problemas, deudas, depresión y angustia, favorece la marginación y culpan a los políticos y al gobierno de su existencia. Se concluye con propuestas de afrontamiento ante el desempleo por parte de participantes.With the theoretical methodological basis of social representations (SR), concepts of employment and unemployment were analyzed in two population groups from the Basque Country: people 20 years old and under and adults over 21 years old. The associative technique of free listings was used in order to know the content and structure of SR, as well as the identification of the central nucleus and the peripheral elements. For the participants employment is an occupation that implies earning money, allows the needs’ satisfaction, and generates happiness. For the group that was 21 years old or older it means, obtaining dignity, to be satisfied and a sure future. Unemployment leads to a lack of money, crisis and poverty, causes hopelessness, depression and overwhelms the person. For the participants over 21 it generates problems, debts, depression, anguish, marginalization and the politicians and the government are blamed for its existence. We conclude with proposals from participants for coping with unemployment

A coordinated control of offshore wind power and bess to provide power system flexibility

Article number 4650The massive integration of variable renewable energy (VRE) in modern power systems is imposing several challenges; one of them is the increased need for balancing services. Coping with the high variability of the future generation mix with incredible high shares of VER, the power system requires developing and enabling sources of flexibility. This paper proposes and demonstrates a single layer control system for coordinating the steady‐state operation of battery energy storage system (BESS) and wind power plants via multi‐terminal high voltage direct current (HVDC). The proposed coordinated controller is a single layer controller on the top of the power converter‐based technologies. Specifically, the coordinated controller uses the capabilities of the distributed battery energy storage systems (BESS) to store electricity when a logic function is fulfilled. The proposed approach has been implemented considering a control logic based on the power flow in the DC undersea cables and coordinated to charging distributed‐BESS assets. The implemented coordinated controller has been tested using numerical simulations in a modified version of the classical IEEE 14‐bus test system, including tree‐HVDC converter stations. A 24‐h (1‐min resolution) quasi-dynamic simulation was used to demonstrate the suitability of the proposed coordinated control. The controller demonstrated the capacity of fulfilling the defined control logic. Finally, the instan-taneous flexibility power was calculated, demonstrating the suitability of the proposed coordinated controller to provide flexibility and decreased requirements for balancing power

Quasi-equilibrium states in thermotropic liquid crystals studied by multiple quantum NMR

We study the nature of the quasiinvariants in nematic 5CB and measure their relaxation times by encoding the multiple quantum coherences of the states following the JB pulse pair on two orthogonal bases, Z and X. The experiments were also performed in powder adamantane at 301 K which is used as a reference compound having only one dipolar quasiinvariant. We show that the evolution of the quantum states during the build up of the quasi-equilibrium state in 5CB prepared under the S condition is similar to the case of adamantane and that their quasi-equilibrium density operators have the same tensor structure. In contrast, the second constant of motion, whose explicit operator form is not known, involves a richer composition of multiple quantum coherences on the X basis of even order, in consistency with the truncation inherent in its definition. We exploited the exclusive presence coherences 4, 6, 8, besides 0 and 2 under the W condition to measure the spin-lattice relaxation time T_{W} accurately, so avoiding experimental difficulties that usually impair dipolar order relaxation measurement such as Zeeman contamination at high fields, and also superposition of the different quasiinvariants. This procedure opens the possibility of measuring the spin-lattice relaxation of a quasiinvariant independent of the Zeeman and S reservoirs, so incorporating a new relaxation parameter useful for studying the complex molecular dynamics in mesophases. In fact, we report the first measurement of T_{W} in a liquid crystal at high magnetic fields. The comparison of the obtained value with the one corresponding to a lower field (16 MHz) points out that the relaxation of the W-order strongly depends on the intensity of the external magnetic field, similarly to the case of the S reservoir, indicating that the relaxation of the W-quasiinvariant is also governed by the cooperative molecular motions.Comment: 7 figures. http://www.famaf.unc.edu.ar/series/AFis2005.ht

Pseudoartrosis de escafoides carpiano tratadas mediante la técnica de Matti-Russe: estudio retrospectivo de 36 casos

Presentamos un estudio retrospectivo de una serie de 36 pacientes con pseudoartrosis de escafoides operados mediante la técnica de Matti-Russe entre 1985 y 1991. Utilizamos injerto córtico esponjoso obtenido del radio (50%), cresta ilíaca (42%) y cúbito (8%) sin diferencias en la incorporación. La tasa de curación fue mayor en las pseudoartrosis medias y distales (80%) que en las de localización proximal (54%). El 80% de los fracasos de curación en la localización media y distal eran pseudoartrosis de más de 30 meses de evolución. Los cambios degenerativos en el carpo de las pseudoartrosis no curadas fueron significativamente mayores (p< 0,001) que en las que se obtuvo la consolidación. La localización y la antiguedad de la pseudoartrosis parecen ser dos importantes factores pronósticos. La técnica de Matti-Russe presenta limitaciones en la pseudoartrosis de localización proximal y en los carpos muy degenerados.We reported a retrospective study of 36 patients with a pseudoarthrosis of the carpal scaphoid bone treated by the Matti-Russe operation from 1985 to 1991. We used radial (50%), iliac (42%) or ulnar (8%) autogenous grafts without any difference in the rate of incorporation. The rate of healing of the pseudoarthrosis was higher in mid and distal location (80%) than in proximal location (54%). In 80% of cases, healing failures in the mid and distal location occurred in old pseudoarthrosis ( >3 0 months evolution). Carpal degenerative changes were significantly higher (p < 0,01) in patients with not healed pseudoarthrosis. The location and the age of the pseudoarthrosis appear to be important prognostic factors. The Matti-Russe technique has limitations when is performed either in proximal pseudoarthrosis or in the presence of advanced radiocarpal osteoarthritis

Fracturas de húmero complicadas con lesión arterial

Presentamos una serie de 10 pacientes afectos de una fractura de húmero asociada a una lesión arterial, tratados entre Enero de 1990 y Octubre de 1993. Dentro de la serie distinguimos tres grupos, de acuerdo con la localización de la fractura (tercio proximal, diáfisis, región supracondílea). El análisis de los resultados sugiere que el peor pronóstico corresponde a las lesiones proximales y diafisarias por su etiología, daños asociados y menor posibilidad de circulación colateral de suplencia. El manejo de estas lesiones complejas exige un tratamiento quirúrgico interdisciplinario. Señalamos la utilidad de la fijación externa como método de osteosíntesis y el uso de un «shunt» provisional para perfundir el miembro durante la cirugía ósea. Se discute la indicación de arteriografía en los traumatismos agudos del miembro superior.A serie of 10 patients with a fracture of the humerus and associated arterial injury treated from January 1990 to October 1993 is reported. The serie was divided in 3 groups acording the proximal, mid shaft or supracondylar location of the fracture. Clinical results indicate a poor prognosis of proximal and mid shaft fractures related to their etiology, associated injuries and damage of the colateral vessels. The management of these complex injuries require an interdisciplinar approach. External fixation is an usefull stabilitation method for fractures associated with vascular damage. The utility of a temporary intraluminar vascular shunt to perfuse the limb at the bone surgery and preoperative arteriography are discussed

Biosorption of Arsenic(III) from Aqueous Solutions by Modified Fungal Biomass of Paecilomyces

The biosorption of As(III) on iron-coated fungal biomass of Paecilomyces sp. was studied in this work. It was found that the biomass was very efficient removing the metal in solution, using Atomic Absorption, reaching the next percentage of removals: 64.5%. The highest adsorption was obtained at pH 6.0, at 30°C after 24 hours of incubation, with 1 mg/L of modified fungal biomass