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1,1-Diphenyl-4-(thiophen-2-yl)but-3-yn-1-ol
(2018-11) Umaña, Christian A.; Pineda Cedeño, Leslie William; Cabezas Pizarro, Jorge A.
The asymmetric unit of the title homopropargyl alcohol, C20H16OS, contains two independent molecules comprising a hydroxy group, a 3-(2-thiophenyl)- propargylic moiety and two aromatic rings linked to a central carbon atom. The two unique molecules are linked into a dimer by an O—HO hydrogen bond. In one molecule, the thiophene ring is disordered over two orientations rotated by 180 with a refined occupancy ratio of 0.575 (4):0.425 (4). The crystal structure is stabilized by O—H and C—H hydrogen-bond interactions. The crystal studied was a two-component non-merohedral twin, the refined ratio of the twin components being 0.575 (4):0.425 (4).
1,3-Bis{[(2,6-dimethylphenyl)sulfanyl]methyl}benzene
(2019) Garita Salazar, Bruno; Pineda Cedeño, Leslie William
The structure of the title compound, C24H26S2, an example of a pincer ligand with an SCS-chelation motif, illustrates the steric effects of the methyl groups in the thiophenyl rings at the 2- and 6-positions, forcing a dissimilar spatial orientation of the thiophenyl rings relative to the central aryl group [dihedral angles = 33.58 (7) and 40.49 (7)°]. In the crystal, weak S⋯S contacts [3.4009 (7) Å] link the molecules into inversion dimers.
1-Nitro-4-(1-propyn-1-yl)benzene
(2019) Campos Fernández, Cristian Saúl; Pineda Cedeño, Leslie William; Cabezas Pizarro, Jorge A.
The title compound, C9H7NO2, was prepared by alkynylation of 4-iodonitrobenzene with 1,3-dilithiopropyne in the presence of 1 equivalent of CuI and catalytic amounts of Pd(PPh3)2Cl2. The complete molecule is generated by crystallographic twofold symmetry with the C—N and C—C[triple bond]C—C units lying on the rotation axis. No directional interactions beyond normal van der Waals contacts could be identified in the packing.
11'-α-Tocomonoenol is the major α-tocomonoenol isomer in cyanobacteria and microalgae from Costa Rica
(2022) Montoya Arroyo, Alexander; Lehnert, Katja; Lux, Peter Erwin; Jiménez García, Víctor; Esquivel Rodríguez, Patricia; Silva Benavides, Ana Margarita; Vetter, Walter; Frank, Jan
α-Tocomonoenols are vitamin E-derivatives with a single double-bond in the tocochromanol sidechain. Currently, two congeners are known: 11′-α-tocomonoenol and 12′-α-tocomonoenol, the later better known as “marine-derived tocopherol” (MDT). Information regarding their presence in photosynthetic aquatic organisms is scarce. We thus determined vitamin E congeners and derivatives in microalgae and cyanobacteria to assess their potential as sources of α-tocomonoenols. Tocochromanols were extracted from freeze-dried cyanobacteria (Arthrospira platensis) and microalgae (Nannochloropsis oceanica, Chlorella vulgaris and Tetraselmis sp.) and quantified by HPLC-FLD. α-Tocomonoenol was quantified in N. oceanica and Tetraselmis sp. where it was the second most abundant tocochromanol following α-tocopherol. LC-MSn and GC-MS confirmed that 11′-α-tocomonoenol and not MDT was the predominant α-tocomonoenol form in evaluated cyanobacteria and microalgae. No significant correlations were observed between tocomonoenol or vitamin E contents and fatty acid profiles. In conclusion, microalgae and particularly Tetraselmis sp. are novel sources of 11′-α-tocomonoenol, a tocochromanol not previously reported in aquatic photosynthetic organisms.
12-HETE is a regulator of PGE2 production via COX-2 expression induced by a snake venom group IIA phospholipase A2 in isolated peritoneal macrophages
(2020) Moreira, Vanessa; Gutiérrez, José María; Lomonte, Bruno; Ramirez Vinolo, Marco Aurélio; Curi, Rui; Lambeau, Gérard; Teixeira, Catarina de Fátima
The snake venom myotoxin (MT)-III is a group IIA secreted phospholipase A2 (sPLA2) with pro-inflammatory activities. Previous studies have demonstrated that MT-III has the ability to stimulate macrophages to release inflammatory lipid mediators derived from arachidonic acid metabolism. Among them, we highlight prostaglandin (PG)E2 produced by the cyclooxygenase (COX)-2 pathway, through activation of nuclear factor (NF)-κB. However, the mechanisms coordinating this process are not fully understood. This study investigates the regulatory mechanisms exerted by other groups of bioactive eicosanoids derived from 12-lipoxygenase (12-LO), in particular 12-hydroxyeicosatetraenoic (12-HETE), on group IIA sPLA2-induced (i) PGE2 release, (ii) COX-2 expression, and (iii) activation of signaling pathways p38 mitogen-activated protein kinases(p38MAPK), protein C kinase (PKC), extracellular signal-regulated kinase 1/2 (ERK1/2), and NF-κB. Stimulation of macrophages with group IIA sPLA2 resulted in release of 12-HETE without modification of 12-LO protein levels. Pre-treatment of these cells with baicalein, a 12-LO inhibitor, decreased the sPLA2-induced PGE2 production, significantly reduced COX-2 expression, and inhibited sPLA2-induced ERK; however, it did not affect p38MAPK or PKC phosphorylation. In turn, sPLA2-induced PGE2 release and COX-2 expression, but not NF-κB activation, was attenuated by pre-treating macrophages with PD98059 an inhibitor of ERK1/2. These results suggest that, in macrophages, group IIA sPLA2-induced PGE2 release and COX-2 protein expression are distinctly mediated through 12-HETE followed by ERK1/2 pathway activation, independently of NF-κB activation. These findings highlight an as yet undescribed mechanism by which 12-HETE regulates one of the distinct signaling pathways for snake venom group IIA sPLA2-induced PGE2 release and COX-2 expression in macrophages.
1999
(Universidad de Costa Rica, 1999) Programa Cooperativo Regional de Frijol para Centroamérica, México y el Caribe (PROFRIJOL)
(1S,3R)-N-{(3S,10S,12S,13R,17R)-12-Hydroxy-17- [(R)-5-hydroxypentan-2-yl]-10,13-dimethylhexa- decahydro-1H-cyclopenta[a]phenanthren-3-yl}- adamantane-1-carboxamide 0.25-hydrate
(2022-10-12) Campos Fernández, Cristian Saúl; Procúpez Schtirbu, Rolando; Soto Tellini, Victor Hugo; Salazar Camacho, Juan Carlos; Jancik, Vojtech
The title compound, C 35H 57 NO 3 0.25H 2O, was synthesized from deoxycholic acid followed by a protection, a Mitsonobu substitution, a Staudinger reduction, formation of an amide and final reduction in the lateral chain. The compound crystallizes in the P1 space group with four steroid molecules and one water molecule in the triclinic cell unit. The crystal structure features O—H O hydrogen bonding. The crystal studied was refined as a non-merohedral twin
25 Years of the Internet in Central America: an interview with Guy de Téramond
(2017-10) Siles González, Ignacio
January 2018 marks the 25th anniversary of the first dedicated Internet connection in Central America. Little is known about the conditions that characterised the early development of the Internet in this part of the globe. In this interview, made on 23 June 2017, Guy de Téramond, more commonly known as “The Father of the Internet in Central America”, recalls some of the main events that led the connection to BITNET and the Internet in this region. De Téramond talks about the motivations, challenges and satisfactions involved in regional connection projects in countries like Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua and Panama, during the 1990s; the role of the Organization of American States; the foundation of academic networks in Central America; and the privatisation of telecommunications in the region. These discussions are updated by addressing the contemporary state of these academic projects and some of the main challenges faced by countries of the Central American region in the global geopolitics and governance of the Internet.
(2922) Proposal to conserve the name Loasa rudis (“Nasa rudis”) against L. rhoeadifolia (Loasaceae)
(2022-10-17) Acuña Castillo, Rafael; Weigend, Maximilian
The genus Nasa was established by Weigend in 2006, encompassing species previously classified under Loasa. The distinction between the two genera is supported by the presence of a single bract per flower, a unique structure of the nectar scale, and molecular evidence. Among the widely collected and distributed taxa in Nasa is N. triphylla subsp. rudis, which spans from southern Mexico to Panama. Recent molecular evidence suggests elevating N. triphylla subsp. rudis to species rank, as it is morphologically and phylogenetically closer to N. dyeri than to the type subspecies of N. triphylla. N. rudis and N. dyeri exhibit distinct characteristics in comparison to N. triphylla, including robust basal stems, dark green calli at the base of petioles, and petals with long filiform appendages. N. rudis can be differentiated from N. dyeri by stem characteristics, stinging trichome cover, and pedicel length. The history of nomenclature for this taxon involves various names under Loasa, and the name "Loasa rhoeadifolia" is considered a synonym. Due to the lack of recognizable type material and the established usage of the name "Loasa rudis," it is recommended to conserve the name Loasa rudis for nomenclatural stability and to avoid further confusion.
2D SLAM Algorithms Characterization, Calibration, and Comparison Considering Pose Error, Map Accuracy, CPU Usage, and Memory Usage
(2022) Trejos Vargas, Kevin Francisco; Rincón Riveros, Laura Camila; Bolaños Torres, Miguel Eduardo; Fallas Pizarro, José Ariel; Marín Paniagua, Leonardo José
The present work proposes a method to characterize, calibrate, and compare, any 2D SLAM algorithm, providing strong statistical evidence, based on descriptive and inferential statistics to bring confidence levels about overall behavior of the algorithms and their comparisons. This work focuses on characterize, calibrate, and compare Cartographer, Gmapping, HECTOR-SLAM, KARTO-SLAM, and RTAB-Map SLAM algorithms, there were four metrics in place, these are pose error, map accuracy, CPU usage, and memory usage, from these four metrics, to characterize them, Plackett-Burman and factorial experiments were performed, and enhancement after characterization and calibration was granted by using hypothesis tests besides central limit theorem.
5,5-Diphenyl-cis-penta-2,4-dienoic acid
(2019) Pineda Cedeño, Leslie William; Amey, Adam R.; Cabezas Pizarro, Jorge A.
In the title compound, C17H14O2, the dihedral angle between the phenyl rings is 76.52 (7)°. In the crystal, pairwise O—H⋯O hydrogen bonds link the molecules into carboxylic acid inversion dimers.
58 Gestión de la calidad en unidades académicas: procesos con incidencia en investigación y acción social
(2022-12-15) Mora Martínez, Esteban Octavio; Hernández Castillo, Juan
La gestión de la calidad de las universidades públicas y privadas suele gestionarse mediante entes acreditadores de la educación superior, nacionales o internacionales. La realidad de algunas unidades académicas especializadas en investigación y capacitación es diferente, y puede ser abordada con sistemas de gestión de la calidad. El objetivo del trabajo es mostrar la experiencia y algunos de los elementos que conforman un sistema de esta índole, cuyo éxito redunda en resultados positivos en los procesos de investigación y acción social en función del mejoramiento continuo, la gestión de riesgos y la posibilidad de aumentar la satisfacción del cliente interno y externo debido a una mayor rigurosidad académica y de gestión para la prestación de los servicios. Se propone de ejemplo al Centro de Investigación y Capacitación en Administración Pública (CICAP), ente adscrito a la Vicerrectoría de la Investigación de la Universidad de Costa Rica (UCR), cuyo modelo de madurez ha pasado por varias etapas en relación con la gestión de la calidad total, como las Normas ISO de la serie 9001, ediciones 2008 y 2015, para avanzar hacia un sistema de gestión para organizaciones educativas, con la Norma ISO 21001 enfocada en este sector.
A aprendizagem de conceitos de probabilísticos: uma experiência de ensino com recurso ao Geogebra com alunos do 100 ano da Costa Rica
(2019-06) Ramírez Montes, Guillermo Enrique; Henriques, Ana Cláudia Correia Batalha
Neste artigo, apresentamos os resultados de um estudo que visa compreender as aprendizagens de conceitos básicos de Probabilidade, de alunos costarriquenhos do 10.º ano, no quadro de uma experiência de ensino apoiada em tarefas exploratórias com recurso ao GeoGebra, e os contributos deste software para essas aprendizagens. O estudo, de natureza qualitativa e interpretativa, tem por base os dados recolhidos através de observação participante das aulas da experiência, recolha documental das resoluções dos alunos das tarefas propostas e questionário. Os resultados evidenciam que as tarefas exploratórias com apoio de simulação permitiram aos alunos aprofundar conceitos básicos de Probabilidade e inferir propriedades associadas, promovendo a sua aprendizagem. No entanto, algumas dificuldades evidenciadas sugerem a necessidade de dar atenção às crenças prévias dos alunos resultantes de experiências do seu quotidiano sobre termos relacionados com o conceito de Probabilidade. O GeoGebra desempenhou um papel importante nestas aprendizagens, facilitando a visualização de representações dos conceitos probabilísticos e a sua exploração dinâmica.
A BDDC algorithm with deluxe scaling for H(curl) in two dimensions with irregular subdomains
(2015) Calvo Alpízar, Juan Gabriel
A bound is obtained for the condition number of a BDDC algorithm for problems posed in H(curl) in two dimensions, where the subdomains are only assumed to be uniform in the sense of Peter Jones. For the primal variable space, a continuity constraint for the tangential average over each interior subdomain edge is imposed. For the averaging operator, a new technique named deluxe scaling is used. Our optimal bound is independent of jumps in the coefficients across the interface between the subdomains and depends only on a few geometric parameters of the decomposition. Numerical results that verify the result are shown, including some with subdomains with fractal edges and others obtained by a mesh partitioner.
A biocomputational platform for the automated construction of large-scale mathematical models of miRNA-transcription factor networks for studies on gene dosage compensation
(2016-11-09) Acón, Man Sai; Siles Canales, Francisco; Mora Rodríguez, Rodrigo Antonio
Cancer complexity and resistance is mediated by cell-to-cell heterogeneity, which is the consequence of the enormous instability of its genetic material. It is unknown how cancer cells are able to withstand the effects of these alterations, while normal cells are typically very sensitive. We hypothesize that cancer requires specific type of stability to survive the enormous chromosomal alterations. This stability may be mediated by a group of genes, whose expression is tightly regulated to maintain viability through a process called gene dosage compensation. This mechanism could be mediated by systems-level properties of complex networks of microRNAs (miRNA) and transcription factors (TF), regulating gene expression despite changes in copy number. Therefore, we designed a biocomputational platform to automatically construct large-scale mathematical models regulating the expression of several candidate genes under dosage compensation. This platform has a broader potential application to other scientific questions involving miRNA and TF networks.
A biogeographical evaluation of high-elevation myxomycete assemblages in the northern Neotropics
(2011-08) Rojas Alvarado, Carlos Alonso; Stephenson, Steven L.; Valverde González, Randall; Estrada Torres, Arturo
This study represented an effort to apply some of the relatively well-known biogeographical and macroecological models to the observed structure of myxomycete assemblages, with emphasis on the northern Neotropical region. A series of 28 experimental plots located in 14 study sites within five different countries was surveyed during two consecutive years using a standard methodology that included both field collections and specimens obtained from moist chamber cultures. Results showed that myxomycetes in high-elevation areas of the northern Neotropics seem to have different levels of preference for macro- and microenvironments, varying degrees of niche breadth and overlap, and different patterns of species occurrence in comparable areas. In a similar manner, species assemblages along a latitudinal gradient that extends from Mexico to Costa Rica showed a decreasing level of similarity with an assemblage studied in the temperate forests of the eastern United Stated and were clearly distinct from an assemblage in Thailand.
A brief survey of Higgs bundles
(2019-06) Zúñiga Rojas, Ronald Alberto
Considering a compact Riemann surface of genus greater or equal than two, a Higgs bundle is a pair composed of a holomorphic bundle over the Riemann surface, joint with an auxiliar vector field, so-called Higgs field. This theory started around thirty years ago, with Hitchin’s work, when he reduced the self-duality equations from dimension four to dimension two, and so, studied those equations over Riemann surfaces. Hitchin baptized those fields as Higgs fields because in the context of physics and gauge theory, they describe similar particles to those described by the Higgs bosson. Later, Simpson used the name Higgs bundle for a holomorphic bundle together with a Higgs field. Today, Higgs bundles are the subject of research in several areas such as non-abelian Hodge theory, Langlands, mirror symmetry, integrable systems, quantum field theory (QFT), among others. The main purposes here are to introduce these objects, and to present a brief but complete construction of the moduli space of Higgs bundles.
A bright future for integrative venomics
(2015-10) Calvete Chornet, Juan José; Lomonte, Bruno
Venomous secretions are produced by a myriad of animal species, from invertebrates to vertebrates. As a general rule, peptides and proteins represent the most abundant and functionally relevant components of these dangerous “cocktails”. It may be argued that the first and indispensable requirement to understand a particular venom is to know its composition, and, to this end, the combination of -omics technologies have emerged as the most powerful tools available to date
A Call for Incorporating Social Research in the Global Struggle against Snakebite
(2015-09-17) Gutiérrez, José María; Burnouf, Thierry; Harrison, Robert A.; Calvete Chornet, Juan José; Brown, Nicholas I.; Jensen, Simon D.; Warrell, David A.; Williams, David J.
In Africa, Asia, Latin America, and parts of Oceania, envenoming after snakebite is a serious public health problem. Conservative data suggest that between 1.2 and 5.5 million people suffer snakebites every year, resulting in 25,000 to 125,000 deaths and leaving approximately 400,000 victims with permanent sequelae. Despite its significant impact on human health, this disease remains largely neglected by national and international health authorities, funding agencies, pharmaceutical companies, patients’ organizations, and health advocacy groups
A call-and-response system facilitates group cohesion among disc-winged bats
(2013) Chaverri Echandi, Gloriana; Gillam, Erin H.; Kunz, Thomas H.
Acoustic signals are important in maintaining group cohesion, particularly in highly mobile species. For these signals to facilitate group cohesion, individuals must be able to recognize, and respond to, calls emitted by group members. In this study, we document the use and recognition of complementary contact calls in Spix’s disc-winged bat (Thyroptera tricolor), a species known to form very stable social groups despite using an extremely ephemeral roosting resource. This bat uses 2 sets of calls: “inquiry,” which are emitted by flying bats that are seeking roosts or group mates, and “response,” which are produced in reply to an inquiry call by individuals that have already located a roost. Here, we test if bats are capable of discriminating between the inquiry and response calls of group and nongroup mates using playback experiments. Results show that flying bats can discriminate between the inquiry and response calls emitted by group and nongroup members and can maintain contact preferentially with the former. Roosting bats, however, exhibited no preference for group over nongroup members and thus responded indiscriminately. We argue that differences in how individuals respond to calls from group and nongroup members may be partly attributed to the costs associated with flight and the potential benefits of recruiting roost mates.

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