Calculation of All Possible Stoichiometric Coefficients and Theoretical Yields of Microbial Global Reactions

Rafael Eduardo Hernández-Guisao,Aranda-Barradas Juan Silvestre,Badillo-Corona Agustín,García-Peña Elvia Inés,Salgado-Manjarrez Edgar 한국생물공학회 2022 Biotechnology and Bioprocess Engineering Vol.27 No.5

Stoichiometric analysis is a crucial step in biochemical processes because it allows us to find the proportions in which the substrates and products react. A system of algebraic equation is obtained from an elemental balance of the participating substances and determined, overdetermined or underdetermined systems can result depending on the number of substances and elements. Underdetermined systems are the most common ones as there are, generally, more substances than elemental balances. However, such systems have been poorly studied and a straightforward way to establish the solution space has not yet been reported. In this work a novel approach for finding all the possible solutions to such underdetermined systems is reported for the first time. The solutions space is expressed as a set of vectors which are here referred as extreme stoichiometries. To illustrate the general applicability and some uses of the proposed approach, three different fermentation systems are analyzed: growth of Chlamydomonas reinhardtii, a mixed culture for hydrogen production, and the growth of Saccharomyces cerevisiae. It is shown how the full stoichiometric spaces can be calculated for heterotrophy, autotrophy, mixotrophy, growth of mixed cultures in mixed substrates and how the experimental results should be contained in such spaces, what permits a consistency analysis. With the proposed method, it is now possible to estimate the maximum yields for any given microbial growth reaction and to assess the congruence of experimental data, even when the system is underdetermined.

Taxonomic Reassessment of the Genus Padina (Dictyotales, Phaeophyta) from the Gulf of California

Rafael Riosmena-Rodriguez,Litzia Paul-Chavez,Gustavo Hernández-Carmona,Juan Manuel López-Vivas,Margarita Casas-Valdez 한국조류학회I 2009 ALGAE Vol.24 No.4

A monographic reassessment of Padina Adanson species from the Gulf of California was developed based on an exhaustive review of the character and characters states that have been used to delimit species in recent and historically valuable collections. Eight names (P. caulescens Thivy in Taylor, P. concrescens Thivy in Taylor, P. crispata Thivy in Taylor, P. durvillaei Bory Saint-Vincent, P. gymnospora [Kützing] Sonder, P. mexicana Dawson, P. tetrastromatica Hauck and P. vickersiae Hoyt in Howe) were reported from the region. An analysis of 1,200 specimens led to the conclusion that only three species (P. durvillaei, P. concrescens and P. mexicana) can be recognized for the area based on four discriminating characters: presence of calcium carbonate in the cell wall; number of medullary cell layers in the basal area; number of medullary cell layers in the middle part and presence/absence of cortical cells. Comparative analysis of the species in the Gulf of California in relation to other recently evaluated species has shown a clear distinction among them suggesting Padina species were overestimated in our area.

Low-grade endometrial stromal sarcoma with intravenous thrombus extension: a multidisciplinary surgical challenge

Alberto Rafael Guijarro-Campillo,Blanca Segarra Vidal,Víctor Lago,Pablo Padilla-Iserte,Josselyn Andrea Hernández Chinchilla,Iván Martín-González,Santiago Domingo del Pozo 대한부인종양학회 2023 Journal of Gynecologic Oncology Vol.34 No.2

Low-grade endometrial stromal sarcoma (LG-ESS) usually exhibits indolent behavior, often misdiagnosed and is associated with a favorable prognosis [1]. Despite the indolent nature of LG-ESS, recurrence is common, the risk is as high as 1 in 3 to 1 in 2 [2]. The behavior of such tumors can lead to invade blood vessels [3]. An intravascular tumor is associated with direct risk of sudden death from pulmonary embolism. There are very few reported cases with clinically obvious intravascular extension. Chemotherapy, radiotherapy and hormone therapy are adjuvant treatments that have not been able to demonstrate a definitive benefit in survival [4]. We want to take advantage of the opportunity, so far unpublished, to demonstrate with this case the surgical challenge described step by step, as well as to demonstrate the importance of surgery as the only curative treatment even in extended intravascular disease [5]. Here in, we present the surgical challenge of a LG-ESS in a 59-year old woman with iliac and cava vein tumoral thrombus extension. We performed a tumoral thrombectomy and vascular repair, with a pelvic exenteration and double barrel wet colostomy. After performing pelvic exenteration, the thrombus with intravascular involvement was addressed at 2 points: inferior cava vein and right common iliac vein with the extraction of the entire thrombus. These defects are corrected by angioplasty and venorrhaphy, respectively. The surgery got a complete cytoreduction. It lasted 290 minutes, with 430 mL blood loss. In patients with LG-ESS, cytoreduction is a reliable option even in extended metastatic disease.

Morphological variability of intertidal Eisenia arborea (Laminariales, Ochrophyta) at Punta Eugenia, Baja California Sur

Gloria M. Parada,Rafael Riosmena-Rodríguez,Enrique A. Martínez,Gustavo Hernández-Carmona 한국조류학회I 2012 ALGAE Vol.27 No.2

Water motion is one of the main drivers in morphological variability in species within de order Laminariales, and most of our current knowledge is based on subtidal populations. Eisenia arborea is a dominant kelp species in the North Pacific, widely distributed along the Baja California Peninsula from mid intertidal down to subtidal areas. This species presents great variability in the intertidal zone but it has not been yet evaluated such variability according to wave exposure. The present work also identifies the spatial / temporal variation, particularly respect to the presence of stipes without medulla (hollow stipes) a feature common among other brown seaweeds. We evaluated the effects of wave action in morphological variation of intertidal Eisenia arborea (Laminariales, Ochrophyta) at Punta Eugenia. The spatial and temporal variation sampling was surveyed between February, May, July, and August 2004 in the intertidal of Punta Eugenia, Baja California Sur. Our results have shown that exposed sites correlate with increased length and width of stipes as compared to more protected sites. Hollow stipes frequency changed more in association with temporal variation than with spatial heterogeneity suggesting nutrient limitation for thalli development. Our results suggest that Eisenia arborea compensate by morphological modifications the stress of living in the intertidal zone by showing larger stipes. Hollow stipes might be are also a mechanical adaptation to increase survival in high energy environments.

Assessment of performance of Lévy flight particle swarm optimization in the estimation of heat source

Obed Cortés-Aburto,José-Alfredo Hernández-Pérez,Rafael Rojas-Rodríguez 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.8

We performed a performance assessment of a recently developed method: Lévy flight particle swarm optimization. This method, which was developed for optimization problems, has shown good results. There is not an application to inverse problems. Now, it is applied for inverse heat transfer, and results are good enough. In particular, a parameter called “limit” is analyzed for different values (from 10 to 150). It shows that performance of the method for estimating parameters in inverse problems is affected by this parameter. When limit reaches a value of 80, ordinary least squares norm and consuming time begin to exhibit better results.

Ramberg–Osgood Stress–Strain Analysis of the Effects of Aging Treatment and Welding on IN600 with a Three-Stage Strain Hardening Behavior

Heriberto Granados‑Becerra,Víctor H. López‑Morelos,Alberto Ruiz,Rafael García‑Hernández,Francisco F. Curiel‑López,Martin R. Barajas‑Alvarez 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

The Ramberg–Osgood equation was applied to model the stress–strain behavior of heat-treated and welded specimens ofInconel 600 up to 0.2 and 0.175 mm/mm of strain, respectively. As-received and aged plates of Inconel 600 were gas metalarc welded to simulate repair of a component in operation. Dog bone shape specimens were tensile tested at a cross headspeed of 0.005 s−1 and the deformation was measured with an extensometer with a gage length of 20 mm. Microstructuralobservations were made in the optical and scanning electron microscope. Fitting the experimental data in the plastic regionof stress–strain curves to a novel three slopes Ramberg–Osgood model enabled estimation of the hardening coefficient, n. The value of n varied from 0.07 to 0.3 depending on the metallurgical condition of the specimen. A notorious increase wasobserved in the value of n for samples heat-treated beyond 25 h and in as-welded samples. The results of this work showeda very good correlation between the model and the experimental curves.

Activated Carbon: A Review of Residual Precursors, Synthesis Processes, Characterization Techniques, and Applications in the Improvement of Biogas

José Aurelio Sosa,José Ramón Laines,David Salvador García,Rafael Hernández,Mark Zappi,Alejandra E. Espinosa de los Monteros 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.3

The energy growing demand and the international environmental policies contribute to the use of renewable energy sources. Among these sources, biogas has acquired great relevance due to its energetic similarity to fuels such as liquefied petroleum gas (LPG) and natural gas (NG). However, biogas needs to be upgraded by removing CO2 and trace gases to obtain biomethane (>85% CH4). This review identifies and classifies seven techniques used in biogas upgrading, reported in academic and scientific publications. A 13-year review period (2008–2021) was considered. Lineal regression was used to analyze the publications number per year. Membranes use represents the largest proportion of publications (33%), while activated carbon (AC) reaches only 22%. However, the use and application of AC obtained the best trend as a publication topic, with a maximum value of R2 = 0.7882. This review documents publish works on obtaining and applying AC in biogas enrichment processes. It includes a review of the characteristics and generation rates of various residual lignocellulosic materials used in the synthesis of AC, the synthesis processes, the characterization techniques, and the final adsorption capacities.