Evolution of the critical oxygen tension

Chang, A.; Compañ Moreno, V.; Weissman, BA. (2018). Evolution of the critical oxygen tension. Contact Lens Spectrum. 33(3):36-39. http://hdl.handle.net/10251/121358S363933

Corneal Equilibrium Flux as a Function of Corneal Surface Oxygen Tension

[EN] Purpose Oxygen is essential for aerobic mammalian cell physiology. Oxygen tension (PO2) should reach a minimum at some position within the corneal stroma, and oxygen flux should be zero, by definition, at this point as well. We found the locations and magnitudes of this ¿corneal equilibrium flux¿ (xmin) and explored its physiological implications. Methods We used an application of the Monod kinetic model to calculate xmin for normal human cornea as anterior surface PO2 changes from 155 to 20 mmHg. Results We find that xmin deepens, broadens, and advances from 1.25 ¿m above the endothelial¿aqueous humor surface toward the epithelium (reaching a position 320 ¿m above the endothelial¿aqueous humor surface) as anterior corneal surface PO2 decreases from 155 to 20 mmHg. Conclusions Our model supports an anterior corneal oxygen flux of 9 ¿L O2 · cm¿2 · h¿1 and an epithelial oxygen consumption of approximately 4 ¿L O2 · cm¿2 · h¿1. Only at the highest anterior corneal PO2 does our model predict that oxygen diffuses all the way through the cornea to perhaps reach the anterior chamber. Of most interest, corneal oxygen consumption should be supported down to a corneal surface PO2 of 60 to 80 mmHg but declines below this range. We conclude that the critical oxygen tension for hypoxia induced corneal swelling is more likely this range rather than a fixed value.Compañ Moreno, V.; Aguilella-Arzo, M.; Weissman, BA. (2017). Corneal Equilibrium Flux as a Function of Corneal Surface Oxygen Tension. Optometry and Vision Science. 94(6):672-679. doi:10.1097/OPX.0000000000001083S67267994

Modeling Corneal Oxygen with Scleral Gas Permeable Lens Wear

[EN] Purpose. The main goal of this current work is to use an updated calculation paradigm, and updated boundary conditions, toprovidetheoreticalguidelinestoassisttheclinicianwhosegoalistoimprovehisorherscleralgaspermeable(GP)contact lens wearing patients¿ anterior corneal oxygen supply. Methods. Our model uses a variable value of corneal oxygen consumption developed through Monod equations that disallows negative oxygen tensions within the stroma to predict oxygen tension at the anterior corneal surface of scleral GP contact lens wearing eyes, and to describe oxygen tension and flux profiles, for various boundary conditions, through the lens, tears, and cornea. We use several updated tissue and boundary parameters in our model. Tear exchange with GP scleral lenses is considered nonexistent in this model. Results. The majority of current scleral GP contact lenses should produce some levels of corneal hypoxia under open eye conditions.Onlylensesproducingthethinnestoftearvaultsshouldresultinanteriorcornealsurfaceoxygentensionsgreaterthana presumed critical oxygen tension of 100 mmHg. We also find that corneal oxygen tension and flux are each more sensitive to modification in tear vault than to changes in lens oxygen permeability, within the ranges of current clinical manipulation. Conclusions. Our study suggests that clinicians would be prudent to prescribe scleral GP lenses manufactured from higher oxygen permeability materials and especially to fit without excessive corneal clearance. (Optom Vis Sci 2016;93:00Y00Compañ Moreno, V.; Aguilella-Arzo, M.; Edrington, TB.; Weissman, BA. (2016). Modeling Corneal Oxygen with Scleral Gas Permeable Lens Wear. Optometry and Vision Science. 93(11):1339-1348. doi:10.1097/OPX.0000000000000988S13391348931

Configurational entropy calculation of poly(α-alkyl β,L-aspartate)s amorphous and crystalline films using gas permeation

The permeability and diffusion coefficient of gases such as N-2, O-2 and CO2 through two polymeric membranes of poly(alpha-alkyl beta,L-aspartate)s (PAALA-n) were determined by the "time-lag" method. One of these membranes was crystalline (PAALA-1) and the other one was amorphous (PAALA-6). The comparison of the obtained result for both membranes is addressed by the calculation of the so called configurational entropy. The study has been done in the range of temperatures 20 degrees C to 70 degrees C.This work was supported by the Direccion General de Investigacion Cientifica y Tecnica (DGICYT), Grant ENE-2011-Ref.24761 and also DGAPA-UNAM Proyecto IN 102512, and SEP-CONACYT 154626.Del Castillo, LF.; Andrio Balado, A.; Nava, JA.; Mollá Romano, S.; Muñoz-Guerra, S.; Compañ Moreno, V. (2014). Configurational entropy calculation of poly(α-alkyl β,L-aspartate)s amorphous and crystalline films using gas permeation. European Polymer Journal. 59:254-261. https://doi.org/10.1016/j.eurpolymj.2014.07.024S2542615

Modification of polyetherimide membranes with ZIFs fillers for CO2 separation

[EN] Flat hybrid membranes composed of polyetherimide (PEI) as matrix and zeolitic imidazolate frameworks (ZIFs) as fillers at concentrations of 10 and 20 wt% were prepared. Apparent permeability coefficient and apparent diffusivity coefficient of gases (CO2 and N-2) for these hybrid membranes (PZIFs) were determined by the "timelag" method. The experimental conditions used were from 25 degrees C to 55 degrees C with pressures of 2, 3 and 5 bar. The PZIFs with fillers of ZIF-8 (PZ-Zn) and ZIF-67 (PZ-Co) showed apparent selectivities (alpha(pa(CO2)/pa(N2))) of 39.6 and 27.5, respectively, higher than the alpha(pa(CO2)/pa(N2)) of the reference membrane PEI, while the membrane with filler of ZIF-Mix (PZ-Zn/Co) showed the lowest alpha(pa(CO2)()/pa(N2)) selectivity of 10.3 in the membrane series (under conditions of 25 degrees C and 2 bar). It is proposed that the selectivity of the membrane series can be attributed to two critical factors: the particle size/distribution ratio in the polymer base and sorption of CO2 at local sites of the bimetallic mixture. On the other hand, gas permeation studies (O-2, CO2 and CH4, and CO2/CH(4 )and CO2/C2H4 mixtures), were carried out in the series of PZIFs membranes. Permeability data were obtained by an isostatic method based on a permeation cell connected in series to a gas chromatograph where the rate of permeated gases was analyzed until a stationary state was reached. The complementary characterization techniques were: scanning electron microscopy, thermogravimetric analysis, and powder X-ray diffraction, which support the existence of the amorphous/crystalline phases of the PZIFs.This research has been supported by the ENE/2015-69203-R project, granted by the Ministerio de Economia y Competitividad (MINECO), Spain; Also authors are grateful to UNAM-DGAPA-PAPIIT projects IG-100185, and IG-114818. This study was partially supported by the CONACyT (Mexico) projects 2013-05-231461 and CB -2014-01-235840.Vega, J.; Andrio, A.; Lemus, A.; Díaz, J.; Del Castillo, L.; Gavara, R.; Compañ Moreno, V. (2019). Modification of polyetherimide membranes with ZIFs fillers for CO2 separation. Separation and Purification Technology. 212:474-482. https://doi.org/10.1016/j.seppur.2018.11.033S47448221

A Grammatical Approach to the Modeling of an Autonomous Robot

Virtual Worlds Generator is a grammatical model that is proposed to define virtual worlds. It integrates the diversity of sensors and interaction devices, multimodality and a virtual simulation system. Its grammar allows the definition and abstraction in symbols strings of the scenes of the virtual world, independently of the hardware that is used to represent the world or to interact with it. A case study is presented to explain how to use the proposed model to formalize a robot navigation system with multimodal perception and a hybrid control scheme of the robot. The result is an instance of the model grammar that implements the robotic system and is independent of the sensing devices used for perception and interaction. As a conclusion the Virtual Worlds Generator adds value in the simulation of virtual worlds since the definition can be done formally and independently of the peculiarities of the supporting devices

Initial learning scenarios based on the computational thinking evaluation for the course Programming fundamentals at INACAP

The paper’s objective is present the design and the planning of initial learning scenarios for the course Programming Fundamentals, from the evaluation of computational thinking to new students of the careers Computer engineering and Programmer analyst of the Technological University of Chile and Training Center Technical respectively at INACAP, to favor the motivation and autonomy of study through the recognition of skills and the use of the instructional design of the face-to-face course. The proposal is based on correspondence with three of five change trends that integrated the educational model. Regarding the Knowledge society, promote recognition of the individuality of the student as a person who will do university studies, that is, the scenarios respond to the fact that each person learns differently. In the Training of competences, contribute with preventive actions that the teacher communicates when there is a lack of specific skills. Finally, in the Flexibility and articulation, provide a diagnostic tool that favors the recognition of previous competences to have an articulated beginning of studies based on the needs of the student. Consequently, contribute to the INACAP´s educational model

Olive oil consumption and all-cause, cardiovascular and cancer mortality in an adult mediterranean population in Spain

Objective: We assessed the association between usual olive oil consumption (OOC) and all-cause, cardiovascular (CVD) and cancer mortality in an adult population in Spain. Materials and methods: OOC was evaluated at baseline in 1,567 participants aged 20 years and older from the Valencia Nutrition Study in Spain using validated food frequency questionnaires. During an 18-year follow-up period, 317 died, 115 due to CVD and 82 due to cancer. Cox regression models were used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (95%CI). Results: After adjusting for demographic and lifestyle factors, the OOC was associated with a lower risk of all-cause, CVD and cancer mortality. Compared to the less than once per month consumption, the consumption of up to one tablespoon per day was associated with a 9% lower risk of all-cause mortality (HR: 0.91; 95%CI: 0.68-1.22) and the consumption of 2 or more tablespoons with a 31% lower risk of all-cause mortality (HR: 0.69; 95%CI: 0.50–0.93; p-trend = 0.011). The consumption of 2 or more tablespoons per day was also associated with lower risk of mortality for CVD (HR: 0.54; 95%CI: 0.32–0.91; p-trend = 0.018) and cancer (HR: 0.49, 95%CI: 0.26–0.94; p-trend = 0.019). Conclusion: Higher olive oil consumption was associated with lower long-term risk of all-cause, CVD and cancer mortality in an adult Mediterranean population. The maximum benefit was observed for the consumption of two or more tablespoons per day. Copyright © 2022 Torres-Collado, García-de la Hera, Lopes, Compañ-Gabucio, Oncina-Cánovas, Notario-Barandiaran, González-Palacios and Vioque.The VNS study was supported by a grant from the Dirección General de Salud Pública, Generalitat Valenciana 1994 and the Fondo Investigacion Sanitaria (FIS 00/0985). This study has also received support from the Instituto de Salud Carlos III FEDER funds (FIS PI13/00654), CIBER of Epidemiology and Public Health (CIBERESP), CB06/02/0013 and ISABIAL

Conductivity study of Zeolitic Imidazolate Frameworks, Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks, and mixed matrix membranes of Polyetherimide/Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks for proton conducting applications

[EN] ZIF-8 (Z8), ZIF-67 (Z67), and ZMix, a Zn/Co bimetallic zeolitic imidazolate framework (ZIF), were synthesized and doped with tetrabutylammonium hydroxide (ZIFsT). The obtained powders were used as fillers for polyetherimide (PEI) at a concentration of 20 wt %. The presence of the three ZIFsT in the polymeric matrix enhanced proton transport relative to that observed for PEI or ZIFs alone. The real and imaginary parts of the complex conductivity were obtained for each of the six materials, and the temperature and frequency dependence of the real part was analyzed. The results at different temperatures show that the dc-conductivity are about three orders of magnitude higher for the doped ZIFsT materials than for the PEI/ZIFsT membranes. In addition, the conductivity of the PEI/ZIFsT membranes increases five or six times when the temperature is changed from 25 °C to 55 °C. For these materials, the conductivity measurements have a linear dependency with frequency, which allowed for the creation of a master curve. It was also found that the PEI/ZMixT membrane activation energy is four times smaller than that of PEI/Z8T membranes and five times smaller than that of PEI/Z67T. Similarly, the real and imaginary parts of the complex dielectric constant were obtained, and the tan ¿ was evaluated. Using this value, the diffusion coefficient and the charge carrier density were obtained. A discussion of the proton transport mechanism through the membrane is given, and a comparison of this work with those on similar electrolyte membranes is included.This research has been supported by the ENE/2015-69203-R project, granted by the Ministerio de Economia y Competitividad (MINECO), Spain, and grants from National Mexican Council for Science and Technology for the scholarships of Ph.D. No. 356825 and mixed scholarship 2015 - MZO2016-mobility in the foreigner granted to Jesus Vega Moreno registered scholarship holder number 256015. Thanks to the CONACYT Program for the fellowship at the Universidad Politecnica de Valencia (UPV) and Universitat Jaume I that PhD student Jesus Vega used to carry out the experimental studies of this work. DGAPA-PAPIIT IG-100315.Vega, J.; Andrio, A.; Lemus, AA.; Del Castillo, LF.; Compañ Moreno, V. (2017). Conductivity study of Zeolitic Imidazolate Frameworks, Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks, and mixed matrix membranes of Polyetherimide/Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks for proton conducting applications. Electrochimica Acta. 258:153-166. https://doi.org/10.1016/j.electacta.2017.10.095S15316625

Conductive films based on composite polymers containing ionic liquids absorbed on crosslinked polymeric ionic-like liquids (SILLPs)

Polymerization of styrenic monomers containing imidazolium subunits in the presence of crosslinking monomers and using ionic liquids (ILs) as porogenic agents provides composite materials with excellent mechanical properties and displaying conductivities that are in the same order of magnitude than those shown by bulk ILs. This approach allows the use of high crosslinking degrees and low IL-loadings without compromising the required properties of the resulting composites. Besides, no appreciable leaching of the bulk IL component is detected.Financial support by Ministerio de Ciencia e Innovacion (CTQ2011-28903-C02-01 and SP-ENE-20120718), Generalitat Valenciana (PROMETEO/2012/020) and Universitat Jaume I (P11B2013-38) is acknowledged.Altava Benito, B.; Compañ Moreno, V.; Andrio Balado, A.; Del Castillo Davila, LF.; Mollá Romano, S.; Burguete, MI.; García-Verdugo Cepeda, E.... (2015). Conductive films based on composite polymers containing ionic liquids absorbed on crosslinked polymeric ionic-like liquids (SILLPs). Polymer. 72:69-81. https://doi.org/10.1016/j.polymer.2015.07.009S69817