Ictiólogos de la Argentina: Mirta Lidia García.

En esta serie se mencionan a todos aquellos que, a través de sus pequeños o grandes aportes, contribuyeron a la consolidación de la disciplina en nuestro país. El plan general de esta contribución consiste en la elaboración de fichas individuales que contengan una lista de trabajos de los diferentes autores, acompañadas por bibliografía de referencia y, cuando ello fuera posible, por imágenes personales y material adicional. Se tratará de guardar un orden cronológico, pero esto no es excluyente, ya que priorizaremos las sucesivas ediciones al material disponible. Este es otro camino para rescatar y revalorizar a quienes en diversos contextos históricos sentaron las bases de lo que hoy es la ictiología nacional. Considero que este es el comienzo de una obra de mayor magnitud en la que se logre describir una parte importante de la historia de las ciencias naturales de la República Argentina.

Comparison of stabilised/solidified mixes of model drill cuttings based on the North Sea and Red Sea Areas

Following the global stringent legislations regulating the wastes generated from the drilling process of oil exploration and production activities, the management of hazardous drill cuttings has become one of the pressing needs confronting the petroleum industry. Most of the prevalent treatment techniques adopted by oil companies are extremely expensive and/or the treated product has to be landfilled without any potential end-use; thereby rendering these solutions unsustainable. The technique of stabilisation/solidification is being investigated in this research to treat drill cuttings prior to landfilling or for potential re-use in construction products. Two case studies were explored namely North Sea and Red Sea. Given the known difficulties with stabilising/solidifying oils and chlorides, this research made use of model drill cutting mixes based on typical drill cutting from the two case studies, which contained 4.2% and 10.95% average concentrations of hydrocarbons; and 2.03% and 2.13% of chlorides, by weight respectively. A number of different binders, including a range of conventional viz. Portland cement (PC) as well as less-conventional viz. zeolite, or waste binders viz. cement kiln dust (CKD), fly ash and compost were tested to assess their ability to treat the North Sea and Red Sea model drill cuttings. The dry binder content by weight was 10%, 20% and 30%. In addition, raw drill cuttings from one of the North Sea offshore rigs were stabilised/solidified using 30% PC. The characteristics of the final stabilised/solidified product were finally compared to those of thermally treated cuttings. The effectiveness of the treatment using the different binder systems was compared in the light of the aforementioned two contaminants only. A set of physical tests (unconfined compressive strength (UCS)), chemical tests (NRA leachability) and micro-structural examinations (using scanning electron microscopy (SEM), and X-ray diffraction (XRD)) were used to evaluate the relative performance of the different binder mixes in treating the drill cuttings. The results showed that the observed UCS covered a wide range of values indicating various feasible end-use scenarios for the treated cuttings within the construction industry. The teachability results showed the reduction of the model drill cuttings to a stable non-reactive hazardous waste, compliant with the UK acceptance criteria for non-hazardous landfills: (a) by most of the 30% and 20% binders for chloride concentrations, and (b) by the 20% and 30% of compost-PC and CKD-PC binders for the Red Sea cuttings. The 20% and 30% compost-PC and CKD-PC binders successfully reduced the leached oil concentration of the North Sea cuttings to inert levels. Copyright 2007, Society of Petroleum Engineers.

La Ictiología Continental Argentina en Imágenes III-Siglo XX (1950-1980)

ProBiota has created this humble document to share it with the “universe of ichthyology” and with those who research and portray the history of science in this region. These images of the past and present of our continental ichthyology of our country are a testimony for the future. Although, in the words of James Joyce: - There is not past, no future; everything flows in an eternal present –

La Bibliografía Científica de Fernando de Buen.

Si bien existen varios ensayos biográficos que enfocan diferentes momentos de su vida (ANÓNIMO, 1963, BAHAMONDE, 1962, LÓPEZ et al., 2015, NION, 2015, PEQUEÑO, 2015, SÁNCHEZ CARRILLO, 2001), hasta donde tenemos conocimiento, no se ha publicado aún una bibliografía completa de la obra del Dr. FERNANDO DE BUEN Y LOZANO (Fig. de tapa). Bibliografías parciales se encuentran, entre otros, en los autores arriba citados. Aquí nos atrevemos a hacer el intento, aunque en forma defectuosa, ya que muchas de sus publicaciones no las hemos podido consultar directamente (se señalan con un asterisco, *). En parte nos hemos basado en una compilación hecha por el propio DE BUEN, que abarca los años 1915 a 1949 (Fig. 1), aunque no siempre con los datos necesarios para una completa información sobre la publicación; en lo posible intentamos complementarla. En sus casi cincuenta años de actividad científica, llegó a producir casi 300 títulos, de variado contenido, aunque siempre relacionados con el medio acuático, sea marino o dulceacuícola. Esta producción se puede dividir en cuatro períodos, que comienza con su etapa española, europea y africana (marroquí), entre 1915 y 1937, durante la cual publicó más de 140 títulos. Como consecuencia de la Guerra Civil Española, en 1939 se radica en México, donde permanece desde el 12 de Julio de 1939 hasta Noviembre 1946, país al que regresa entre 1953 y 1957. Durante este período escribe unos 70 artículos. Entre esas dos etapas mexicanas, estuvo brevemente radicado en el Uruguay, desde el 26 de Noviembre de 1946 hasta 1953, sin duda la etapa de menor producción científica, con una docena trabajos. A ésta sigue el último período de su vida, en Chile (Fig. 2), la que lamentablemente termina trágicamente, en 1962. Durante este período publica más de 60 publicaciones, de los cuales, aparentemente, seis quedan inéditas. Cabe señalar que durante estas tres etapas de exilio americano, si bien sus publicaciones están mayoritariamente relacionadas con el país de residencia, hay algunas excepciones. Preivo a estas estadías en América, hay que mencionar tres europeas, fuera de España, a saber: en el Museo Oceanográfico de Mónaco (1919), en el Instituto Centrale di Biologia Marina, Messina, Italia (1919), y en el Laboratorio Arago, Banyuls sur Mer, Francia (1939). En general, puede considerarse que FERNANDO DE BUEN fue un investigador solitario, ya que solamente seis, de sus casi 300 trabajos, fueron publicados en colaboración: dos con su hermano SADÍ DE BUEN (#31 y 32), dos con F. FRADE (#115 y 116), y dos con MANUEL ZOZAYA (#162 y 176). En su obra científica hemos podido identificar la descripción original de 12 géneros, 9 subgéneros, 54 especies y 11 subespecies, como se indican en la Tabla I.

Fermín Eguía.

Esta serie tiene como propósito mostrar diferentes expresiones artísticas relacionadas con la Ictiología nacional y regional, generadas en diferentes épocas y que surgen por diversas motivaciones personales que, en algún caso, muestran casi con exactitud a los modelos que inspiraron la obra, en otras, por lo contrario, responden a la imaginación y creatividad del autor. En este artículo se documenta parte de la obra del pintor, dibujante e ilustrador argentino Fermín Eguía relacionada con la temática de peces y el Delta del Paraná como un modesto homenaje a este notable artista.

Shock transmission and eigenvalue veering within a coupled system.

The operation of dynamical systems in harsh environments requires continuous monitoring. Internal sensors may be used to monitor the conditions in real time. A typical example is the sensor and electronic components used in space structures which, especially during launch, are subject to huge g force. The paper will present an experimental and theoretical study on a simplified model used to analyze the possible cause of high acceleration on the enclosed sensors and equipments due to impulsive loading. The model system consists of two beams coupled using compliant connections. An impulse hammer excites one beam, and vibrations are transmitted to the indirectly driven beam. A theoretical model is developed using a Rayleigh-Ritz approach and validated using experimental results in both the frequency and time domains. Monto Carlo simulation was done with random masses positioned on the indirectly driven beam to determine the worst-case conditions for maximum peak acceleration. Highest acceleration levels were found when mode matching in the two beams led to veering behavior in the coupled modes. The results suggest guidelines for the detailed design of internal components of a structure exposed to shock loading from its environment. [The authors thank Schlumberger Cambridge Research for financial support.].

中国主要地方品种猪血液蛋白遗传多样性研究

实验采用水平板淀粉凝胶电泳技术,对中国地方猪五大类型9个品种、1个引入品种共201个个体进行了遗传多样性分析。共分析遗传座位30个,其中只有MDH、PEPB、AK、6PGD、ADA、PHI 6个座位具有多态性。中国主要地方猪品种的多态座位百分比P=0.200,平均杂合度H=0.065,平均等位基因数A=1.300。根据基因频率采用PHYLIP3.5c软件包计算Nei氏遗传距离,然后用“NEIGHBOR”程序分别构建NJ和UPGMA系统树。

浙江地方猪种遗传多样性研究

采用蛋白电泳和线粒体DNA RFLP分析方法,研究了浙江七个地方品种猪及浙江野猪的遗传多样性状况。从分析的30个遗传座位、99个地方品种个体中发现MDH,PEPB,6PGD,AK,ADA,PHI六个座位具有多态性,其中AK,MDH多态座位在家猪中首次发现。浙江地方猪种的亲缘关系很近。在mtDNA RFLP水平,25种限制性内切酶在27个地方品种个体及3个野猪个体中共检出30种限制性态型,可归结成三种单倍型。各单倍型间平均遗传距离(P)为0.005,群体平均多态度(#pi#))为0.000 8,处于遗传多样性贫乏范围。

Genetic diversity of Chinese native pigs inferred from protein electrophoresis

We examined protein polymorphism of 20 native pig breeds in China and 3 introduced pig breeds. Thirty loci have been investigated, among which six loci were found to be polymorphic. Especially, the polymorphism of malate dehydrogenase (MDH), adenylate kinase (AK), and two new alleles of adenosine deaminase (ADA) had not been reported in domestic pigs and wild pigs. The percentage of polymorphic loci (P), the mean heterozygosity (H), and the mean number of alleles (A) are 0.200, 0.065, and 1.300, respectively. The degree of genetic variability of Chinese pigs as a whole was higher than that of goats, lower than that of cattle and horses, and similar to that of sheep. Using the gene frequencies of the 30 loci, Nei's genetic distance among the 20 native breeds in China and 3 introduced pig breeds was calculated by the formula of Nei. The program NEIGHBOR in PHYLIP 3.5c was chosen to construct an UPGMA tree and a NJ tree. Our results show that, of the total genetic variation found in the native pig breeds in China, 31% (0.31) is ascribable to genetic differences among breeds. About 69% of the total genetic variation is found within breeds. Most breeds are in linkage disequilibrium. The patterns of genetic similarities between the Chinese native pig breeds were not in agreement with the proposed pig type classification.

Effects of constraint curvature on structural instability: tensile buckling and multiple bifurcations

Bifurcation of an elastic structure crucially depends on the curvature of the constraints against which the ends of the structure are prescribed to move, an effect which deserves more attention than it has received so far. In fact, we show theoretically and we provide definitive experimental verification that an appropriate curvature of the constraint over which the end of a structure has to slide strongly affects buckling loads and can induce: (i.) tensile buckling; (ii.) decreasing- (softening), increasing- (hardening), or constant-load (null stiffness) postcritical behaviour; (iii.) multiple bifurcations, determining for instance two bifurcation loads (one tensile and one compressive) in a single-degree-of-freedom elastic system. We show how to design a constraint profile to obtain a desired postcritical behaviour and we provide the solution for the elastica constrained to slide along a circle on one end, representing the first example of an inflexional elastica developed from a buckling in tension. These results have important practical implications in the design of compliant mechanisms and may find applications in devices operating in quasi-static or dynamic conditions.

In vitro anti-HIV and -HSV activity and safety of sodium rutin sulfate as a microbicide candidate

Sodium rutin sulfate (SRS) is a sulfated rutin modified from the natural flavonol glycoside rutin. Here, we investigated its in vitro anti-HIV and -HSV activities and its cytotoxic profile. Fifty percent inhibitory concentration (IC50) values of SRS against HIV-1 X4 virus IIIB, HIV-1 R5 isolates Ada-M and Ba-L were 2.3 +/- 0.2, 4.5 +/- 2.0 and 8.5 +/- 3.8 mu M with a selectivity index (SI) of 563, 575 and 329, respectively. Its IC50 against primary R5 HIV-1 isolate from Yunnan province in China was 13.1 +/- 5.5 mu M, with a Sl of 197. In contrast, unsulfated rutin had no activity against any of the HIV-1 isolates tested. Further study indicated that SRS blocked viral entry and virus-cell fusion likely through interacting with the HIV- I envelope glycoprotein. SRS also demonstrated some activity against human herpes simplex virus (HSV) with an IC50 of 88.3 +/- 0.1 mu M and a Sl of 30. The 50% cytotoxicity concentration (CC50) of SRS was >3.0 mM, as determined in human genital ME 180, HeLa and primary human foreskin fibroblast cells. Minimum inhibitory concentration of SRS for vaginal lactobacilli was >3.0 mM. These results collectively indicate that SRS represents a novel candidate for anti-HIV-1/HSV microbicide development. (C) 2007 Elsevier B.V. All rights reserved.

Nanoindentation of biological and biomimetic materials

Nanoindentation techniques have recently been adapted for the study of biological materials. This feature will consider the experimental adaptations required for such studies. Following a brief review of the structure and constitutive behavior of biological materials, we examine the experimental aspects in detail, including working with hydrated samples, time-dependent mechanical behavior and extremely compliant materials. The analysis of experimental data, consistent with the constitutive response of the material, will then be treated. Examples of nanoindentation data collected using commercially-available instruments are shown, including nanoindentation creep curves of biological materials and relaxation responses of biomimetic hydrogels. Finally, we conclude by examining the current state and future needs of the biological nanoindentation community. © 2011, Society for Experimental Mechanics.

Composite electrospun gelatin fiber-alginate gel scaffolds for mechanically robust tissue engineered cornea.

A severe shortage of good quality donor cornea is now an international crisis in public health. Alternatives for donor tissue need to be urgently developed to meet the increasing demand for corneal transplantation. Hydrogels have been widely used as scaffolds for corneal tissue regeneration due to their large water content, similar to that of native tissue. However, these hydrogel scaffolds lack the fibrous structure that functions as a load-bearing component in the native tissue, resulting in poor mechanical performance. This work shows that mechanical properties of compliant hydrogels can be substantially enhanced with electrospun nanofiber reinforcement. Electrospun gelatin nanofibers were infiltrated with alginate hydrogels, yielding transparent fiber-reinforced hydrogels. Without prior crosslinking, electrospun gelatin nanofibers improved the tensile elastic modulus of the hydrogels from 78±19 kPa to 450±100 kPa. Stiffer hydrogels, with elastic modulus of 820±210 kPa, were obtained by crosslinking the gelatin fibers with carbodiimide hydrochloride in ethanol before the infiltration process, but at the expense of transparency. The developed fiber-reinforced hydrogels show great promise as mechanically robust scaffolds for corneal tissue engineering applications.

Integrated high pressure microhydraulic actuation and control for surgical instruments

To reduce the surgical trauma to the patient, minimally invasive surgery is gaining considerable importance since the eighties. More recently, robot assisted minimally invasive surgery was introduced to enhance the surgeon's performance in these procedures. This resulted in an intensive research on the design, fabrication and control of surgical robots over the last decades. A new development in the field of surgical tool manipulators is presented in this article: a flexible manipulator with distributed degrees of freedom powered by microhydraulic actuators. The tool consists of successive flexible segments, each with two bending degrees of freedom. To actuate these compliant segments, dedicated fluidic actuators are incorporated, together with compact hydraulic valves which control the actuator motion. Especially the development of microvalves for this application was challenging, and are the main focus of this paper. The valves distribute the hydraulic power from one common high pressure supply to a series of artificial muscle actuators. Tests show that the angular stroke of the each segment of this medical instrument is 90°. © 2012 Springer Science+Business Media, LLC.

Flexible pneumatic micro-actuators: Analysis and production

Compliant pneumatic micro-actuators are interesting for applications requiring large strokes and forces in delicate environments. These include for instance minimally invasive surgery and assembly of microcomponents. This paper presents a theoretical and experimental analysis of a balloon-type compliant micro-actuator. Finite element modeling is used to describe the complex behavior of these actuators, which is validated through prototype experiments. Prototypes with dimensions ranging from 11mm × 2mm × 0.24mm to 4mm × 1mm × 0.12mm are fabricated by a newly developed production process based on micromilling and micromolding. The larger actuators are capable of delivering out-of-plane strokes of up to 7mm. Further, they have been integrated in a platform with two rotational and one translational degree of freedom. © 2011 Published by Elsevier Ltd.