Surface Analysis, Microstructural, Mechanical and Electrochemical Properties of New Ti-15Ta-5Zr Alloy

Cora Vasilescu,Silviu Iulian Drob,Petre Osiceanu,Paula Drob,Jose Maria Calderon Moreno1,Silviu Preda,Steliana Ivanescu,Ecaterina Vasilescu 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.2

This paper describes the synthesis of a novel Ti-15Ta-5Zr alloy with an  + β stable, homogeneous, biphasicmicrostructure (by optical microscopy, X-ray diffraction and scanning electron microscopy) and the determinationof its mechanical properties, hardness and a Young’s modulus of 42.2 GPa. The alloy passive film compositionand thickness were analyzed by X-ray photoelectron spectroscopy; a thick, compact native passive filmcontaining the protective oxides of all constituent elements (TiO2, Ta2O5, ZrO2) was identified. The electrochemicalparameters confirmed a nobler behaviour and a more capacitive, resistant passive film on thealloy surface compared to Ti and other existing implant alloys; these facts are due to the alloying elements that,by their oxides stabilize and reinforce the alloy passive film. This passive film thickened in time, which increased itsprotective capacity. The new alloy had no susceptibility to galvanic or local corrosion. Ti-15Ta-5Zr alloyis recommended as an advanced orthopaedic implant material.

Dexamethasone and COVID-19 in a Developing Country: Appropriate Use?

( Diego Martin Moreno Marreros ),( Maycol Leonardo Aburto Moreno ),( Kattia Gassely Torres Gil ),( Carlos Morera Guzman ) 대한결핵 및 호흡기학회 2021 Tuberculosis and Respiratory Diseases Vol.84 No.3

Fluorescence Guided Surgery with 5-Aminolevulinic Acid for Resection of Spinal Cord Ependymomas

Rafael García Moreno,Luis Miguel Bernal García,Hyaissa Ippolito Bastidas,Carlos Andrés Mondragón Tirado,Aurora Moreno Flores,Juan Pablo Sosa Cabezas,José Manuel Cabezudo Artero 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.1

Study Design: A retrospective study. Purpose: We report our experience with 5-aminolevulinic acid (5-ALA)–assisted resection of spinal cord ependymomas in adults. Overview of Literature: Ependymoma is the most frequent primary spinal cord tumor in adults. Surgery is the treatment of choice in most cases. However, while complete resection is achieved in approximately 80% of cases, clinical improvement is achieved in 15% only. Five-ALA fluorescence–guided surgery seems to be useful for this tumor type. Methods: We studied 14 patients undergoing 5-ALA fluorescence-guided surgery for spinal cord ependymomas in our service. The modified McCormick classification was used to determine clinical status and the degree of resection was assessed with magnetic resonance imaging. Results: Of the 14 patients, the tumor showed an intense emission of fluorescence in 12 and the fluorescence was weak and nonuniform in two. Complete resection was achieved in 11 cases. According to the McCormick classification, 10 patients improved, two remained the same, and two deteriorated. Conclusions: Our results confirm that 5-ALA fluorescence-guided resection is useful in spinal cord ependymoma resection. Although the rate of complete resections is similar to that in published series without 5-ALA, clinical results are better when using 5-ALA with a lower percentage of clinical deterioration.

Biochemical Characterization of Recombinant L-Asparaginase (AnsA) from Rhizobium etli, a Member of an Increasing Rhizobial-Type Family of L-Asparaginases

( Moreno Enriquez Angelica ),( Zahaed Evangelista Martinez ),( Edith G. Gonzalez-mondragon ),( Arturo Calderon Flores ),( Roberto Arreguin ),( Ernesto Perez Rueda ),( Alejandro Huerta Saquero ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.3

We report the expression, purification, and characterization of L-asparaginase (AnsA) from Rhizobium etli. The enzyme was purified to homogeneity in a single-step procedure involving affinity chromatography, and the kinetic parameters Km, Vmax, and kcat for L-asparagine were determined. The enzymatic activity in the presence of a number of substrates and metal ions was investigated. The molecular mass of the enzyme was 47 kDa by SDS-PAGE. The enzyme showed a maximal activity at 50oC, but the optimal temperature of activity was 37oC. It also showed maximal and optimal activities at pH 9.0. The values of Km, Vmax, kcat, and kcat/Km were 8.9±0.967×10-3 M, 128±2.8 U/mg protein, 106±2 s-1, and 1.2±0.105×104M-1s-1, respectively. The L-asparaginase activity was reduced in the presence of Mn2+, Zn2+, Ca2+, and Mg2+ metal ions for about 52% to 31%. In addition, we found that NH4 +, L-Asp, D-Asn, and β-aspartyl-hydroxamate in the reaction buffer reduced the activity of the enzyme, whereas L-Gln did not modify its enzymatic activity. This is the first report on the expression and characterization of the L-asparaginase (AnsA) from R. etli. Phylogenetic analysis of asparaginases reveals an increasing group of known sequences of the Rhizobialtype asparaginase II family.

Analysis of productivity, efficiency, and their explanatory factors in the fast fashion sector: New evidence from the international environment

Moreno Justo de Jorge,Velázquez Francisco Javier Martínez 한국마케팅과학회 2023 Journal of Global Fashion Marketing Vol.14 No.4

This paper analyses the performance levels of the leading compa- nies in the fast fashion sector, Inditex, H&M and Gap in the period 2005–2019. Additionally, the isolated analysis of Inditex, as a case study, has been considered, with special emphasis on its interna- tionalization process, in the period 1995–2019. The use of different approaches to obtain efficiency and productivity (DEA, intertem- poral and Windows models), have enriched this work. The results obtained indicate a good performance in the resource manage- ment of the companies analyzed. In the case of Inditex, a curvilinear U-shaped relationship was found between efficiency and its level of internationalization. In addition, average increases in TFP are observed in the case of Gap and Inditex. However, Inditex shows a trend of continuous improvement in most of the sub-periods considered, reaching an improvement of 18%.

Artificial gametes from stem cells

Moreno, Inmaculada,Miguez-Forjan, Jose Manuel,Simon, Carlos The Korean Society for Reproductive Medicine 2015 Clinical and Experimental Reproductive Medicine Vol.42 No.2

The generation of artificial gametes is a real challenge for the scientific community today. In vitro development of human eggs and sperm will pave the way for the understanding of the complex process of human gametogenesis and will provide with human gametes for the study of infertility and the onset of some inherited disorders. However, the great promise of artificial gametes resides in their future application on reproductive treatments for all these people wishing to have genetically related children and for which gamete donation is now their unique option of parenthood. This is the case of infertile patients devoid of suitable gametes, same sex couples, singles and those fertile couples in a high risk of transmitting serious diseases to their progeny. In the search of the best method to obtain artificial gametes, many researchers have successfully obtained human germ cell-like cells from stem cells at different stages of differentiation. In the near future, this field will evolve to new methods providing not only viable but also functional and safe artificial germ cells. These artificial sperm and eggs should be able to recapitulate all the genetic and epigenetic processes needed for the correct gametogenesis, fertilization and embryogenesis leading to the birth of a healthy and fertile newborn.

A methodology to derive global maps of leaf traits using remote sensing and climate data

Moreno-Martí,nez, Á,lvaro,Camps-Valls, Gustau,Kattge, Jens,Robinson, Nathaniel,Reichstein, Markus,van Bodegom, Peter,Kramer, Koen,Cornelissen, J. Hans C.,Reich, Peter,Bahn, Michael,Niineme Elsevier 2018 Remote sensing of environment Vol.218 No.-

<P><B>Abstract</B></P> <P>This paper introduces a modular processing chain to derive global high-resolution maps of leaf traits. In particular, we present global maps at 500 m resolution of specific leaf area, leaf dry matter content, leaf nitrogen and phosphorus content per dry mass, and leaf nitrogen/phosphorus ratio. The processing chain exploits machine learning techniques along with optical remote sensing data (MODIS/Landsat) and climate data for gap filling and up-scaling of in-situ measured leaf traits. The chain first uses random forests regression with surrogates to fill gaps in the database (> 45<I>%</I> of missing entries) and maximizes the global representativeness of the trait dataset. Plant species are then aggregated to Plant Functional Types (PFTs). Next, the spatial abundance of PFTs at MODIS resolution (500 m) is calculated using Landsat data (30 m). Based on these PFT abundances, representative trait values are calculated for MODIS pixels with nearby trait data. Finally, different regression algorithms are applied to globally predict trait estimates from these MODIS pixels using remote sensing and climate data. The methods were compared in terms of precision, robustness and efficiency. The best model (random forests regression) shows good precision (normalized RMSE≤ 20<I>%</I>) and goodness of fit (averaged Pearson's correlation R = 0.78) in any considered trait. Along with the estimated global maps of leaf traits, we provide associated uncertainty estimates derived from the regression models. The process chain is modular, and can easily accommodate new traits, data streams (traits databases and remote sensing data), and methods. The machine learning techniques applied allow attribution of information gain to data input and thus provide the opportunity to understand trait-environment relationships at the plant and ecosystem scales. The new data products – the gap-filled trait matrix, a global map of PFT abundance per MODIS gridcells and the high-resolution global leaf trait maps – are complementary to existing large-scale observations of the land surface and we therefore anticipate substantial contributions to advances in quantifying, understanding and prediction of the Earth system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Presented a modular process chain for plant trait mapping including local effects </LI> <LI> High-resolution global maps of leaf traits by fusing measured trait data, LANDSAT and MODIS </LI> <LI> Scope for testing and parameterizing trait-enabled Earth System models </LI> <LI> Implications for land management and Earth system science applications </LI> </UL> </P>

Analytical and multicoupled methods for optimal steady-state thermoelectric solutions

Moreno-Navarro, Pablo,Perez-Aparicio, Jose L.,Gomez-Hernandez, J.J. Techno-Press 2022 Coupled systems mechanics Vol.11 No.2

Peltier cells have low efficiency, but they are becoming attractive alternatives for affordable and environmentally clean cooling. In this line, the current article develops closed-form and semianalytical solutions to improve the temperature distribution of Bi₂Te₃ thermoelements. From the distribution, the main objective of the current work-the optimal electric intensity to maximize cooling-is inferred. The general one-dimensional differential coupled equation is integrated for linear and quadratic geometry of thermoelements, under temperature constant properties. For a general shape, a piece-wise solution based on heat flux continuity among virtual layers gives accurate analytical solutions. For variable properties, another piece-wise solution is developed but solved iteratively. Taking advantage of the formulae, the optimal intensity is directly derived with a minimal computational cost; its value will be of utility for more advanced designs. Finally, a parametric study including straight, two linear, barrel, hourglass and vase geometries is presented, drawing conclusions on how the shape of the thermoelement affects the coupled phenomena. A specially developed coupled and non-linear finite element research code is run taking into account all the materials of the cell and using symmetries and repetitions. These accurate results are used to validate the analytical ones.

Linear elastic mechanical system interacting with coupled thermo-electro-magnetic fields

Moreno-Navarro, Pablo,Ibrahimbegovic, Adnan,Perez-Aparicio, Jose L. Techno-Press 2018 Coupled systems mechanics Vol.7 No.1

A fully-coupled thermodynamic-based transient finite element formulation is proposed in this article for electric, magnetic, thermal and mechanic fields interactions limited to the linear case. The governing equations are obtained from conservation principles for both electric and magnetic flux, momentum and energy. A full-interaction among different fields is defined through Helmholtz free-energy potential, which provides that the constitutive equations for corresponding dual variables can be derived consistently. Although the behavior of the material is linear, the coupled interactions with the other fields are not considered limited to the linear case. The implementation is carried out in a research version of the research computer code FEAP by using 8-node isoparametric 3D solid elements. A range of numerical examples are run with the proposed element, from the relatively simple cases of piezoelectric, piezomagnetic, thermoelastic to more complicated combined coupled cases such as piezo-pyro-electric, or piezo-electro-magnetic. In this paper, some of those interactions are illustrated and discussed for a simple geometry.

Uniform Output Subsidies in Economic Unions Versus Profit-shifting Export Subsidies

Moreno, Bernardo,Torres, Jose´L. 세종대학교 국제경제연구소 2001 Journal of Economic Integration Vol.16 No.4

This paper focuses on the effect of output subsidies in an economic union in the context of a third-market model where there are two countries which produce a homogeneous good consumed in a third country. We study the importance of cost asymmetry between firms in different countries, and the elasticity of demand in the caase of countries that join an economic union with harmonized output subsidis. We find that the optimal level of subsidy in the economic union can be negative (a tax) if firms have different costs and the demand is concave. We also compare the optimal subsidy in the economic union with the pre-union export subsidies with the result that the new policy generally favours the less efficient countries.