Assessment of Austenite Static Recrystallization and Grain Size Evolution during Multipass Hot Rolling of a Niobium-Microalloyed Steel

Manuel Gómez,Lucía Rancel,Sebastián F. Medina 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.4

Double-deformation isothermal tests and multipass continuous-cooling hot torsion tests were used to study the evolution of austenite microstructures during isothermal and non-isothermal hot deformation of an Nb microalloyed steel. These tests, coupled with microstructural characterization, have verified that the no-recrystallization temperature (Tnr) corresponds roughly to the temperature where recrystallization starts to be incomplete during rolling. An accurate method to estimate the recrystallized fraction during hot rolling based on stress-strain data, and which does not require metallographic studies, is proposed. The results of this method have been successfully compared to metallographic measurements, the values of non-isothermal fractional softening and the accumulated stress measured in the plots of mean flow stress (MFS) versus the inverse of temperature. A remarkable austenite grain refinement occurs in the first hot rolling passes after reheating. The correlation of isothermal and continuous cooling tests is better understood if the effect of grain size on recrystallization and precipitation is taken into account. Double-deformation isothermal tests and multipass continuous-cooling hot torsion tests were used to study the evolution of austenite microstructures during isothermal and non-isothermal hot deformation of an Nb microalloyed steel. These tests, coupled with microstructural characterization, have verified that the no-recrystallization temperature (Tnr) corresponds roughly to the temperature where recrystallization starts to be incomplete during rolling. An accurate method to estimate the recrystallized fraction during hot rolling based on stress-strain data, and which does not require metallographic studies, is proposed. The results of this method have been successfully compared to metallographic measurements, the values of non-isothermal fractional softening and the accumulated stress measured in the plots of mean flow stress (MFS) versus the inverse of temperature. A remarkable austenite grain refinement occurs in the first hot rolling passes after reheating. The correlation of isothermal and continuous cooling tests is better understood if the effect of grain size on recrystallization and precipitation is taken into account.

The Role of Lipids in Development of Allergic Responses

Manuel Gómez del Moral,Eduardo Martínez-Naves 대한면역학회 2017 Immune Network Vol.17 No.3

Most allergic diseases are caused by activation of Th2 type immune responses resulting in the production of specific IgE against proteins found in normally harmless substances such as pollen, mites, epithelia or food. Allergenic substances are composed, in addition to proteins, of other compounds such as carbohydrates and lipids. Those lipids are able to promote the development of Th2-type responses associated with allergy. There are lipids found in pollen, milk or insect venom that are specifically recognized by CD1 restricted unconventional T lymphocytes, which can promote allergic reactions. Furthermore, a large number of allergens are proteins containing hydrophobic parts that specifically bind lipids that are capable to favor allergenic immune responses. Also, lipids associated to substances like pollen, dander, epithelia or the bacteria can act on cells of the innate system, including dendritic cells, which in turn lead to the differentiation of Th2-type clones. Finally, lipids may also influence the ability of allergens to be exposed to the immune system within the oral, respiratory or intestinal mucosa where allergic response occurs with great frequency.

Trade Integration and Intra-national Business Cycle Synchronization: Evidence from Mexico’s States from 1980 to 2019

Manuel Gómez-Zaldívar,Fernando Garcia-Barragan 세종대학교 경제통합연구소 2022 Journal of Economic Integration Vol.37 No.2

This study documents the adjustment in the business cycles of Mexico’s states that resulted from trade liberalization. It also analyzes the relevance of the various elements that previous studies have proposed as the determining factors of the synchronization of these cycles. Our results reveal that these determinants are relevant throughout the sample period (1980-2019), but their relative importance changes over time as does their synchronization. This may be explained as follows: trade liberalization caused a regional and sectoral reallocation of resources, which in turn led to some states becoming increasingly interlinked based on their economic structures, whereas the remaining states became less synchronized with the former states. This case should be of interest to other developing countries that are dependent on the world’s capital and trade flows and whose regions may respond heterogeneously if they have diverse economic structures as those of Mexico.

Enhanced CO2 capture by cupuassu shell-derived activated carbon with high microporous volume

Cruz Orlando F.,Campello-Gómez Ignacio,Casco Mirian E.,Serafin Jarosław,Silvestre-Albero Joaquín,Martínez-Escandell Manuel,Hotza Dachamir,Rambo Carlos R. 한국탄소학회 2023 Carbon Letters Vol.33 No.3

Here, we report the preparation of microporous-activated carbons from a Brazilian natural lignocellulosic agricultural waste, cupuassu shell, by pyrolysis at 500 ºC and KOH activation under different experimental conditions and their subsequent application as adsorbent for CO2 capture. The effect of the KOH:precursor ratio (wt/wt%) and the activation temperature on the porous texture of activated carbons have been studied. The values of specific surface area ranged from 1132 to 2486 m2/g, and the overall micropore volume ranged from 0.73 to 1.02 cm3/g. Carbons activated with 2:1 ratio of KOH and activation temperature of 700 ºC presented a CO2 adsorption at 1 bar of 7.8 and 4.4 mmol/g at 0 °C and 25 ºC, respectively. The isosteric heat of adsorption, Qst , was calculated for all samples by applying the Clausius–Clapeyron approach to CO2 adsorption isotherms at both temperatures. The values of CO2 adsorption capacities are among the highest reported in the literature, especially for activated carbons produced from biomass.

Low-Voltage Tunable Pseudo-Differential Transconductor with High Linearity

Juan Antonio Gómez,Melita Pennisi,Antonio Lopez Martin,Ramon González Carvajal,Jaime Ramírez-Angulo,Manuel Pedro Carrasco 한국전자통신연구원 2009 ETRI Journal Vol.31 No.5

A novel tunable transconductor is presented. Input transistors operate in the triode region to achieve programmable voltage-to-current conversion. These transistors are kept in the triode region by a novel negative feedback loop which features simplicity, low voltage requirements, and high output resistance. A linearity analysis is carried out which demonstrates how the proposed transconductance tuning scheme leads to high linearity in a wide transconductance range. Measurement results for a 0.5 μm CMOS implementation of the transconductor show a transconductance tuning range of more than a decade (15 μA/V to 165 μA/V) and a total harmonic distortion of -67 dB at 1 MHz for an input of 1 Vpp and a supply voltage of 1.8 V.

Role of Multiparametric Prostate Magnetic Resonance Imaging before Confirmatory Biopsy in Assessing the Risk of Prostate Cancer Progression during Active Surveillance

Salguero Joseba,Gómez-Gómez Enrique,Valero-Rosa José,Carrasco-Valiente Julia,Mesa Juan,Martin Cristina,Campos-Hernández Juan Pablo,Rubio Juan Manuel,López Daniel,Requena María José 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.4

Objective: To evaluate the impact of multiparametric magnetic resonance imaging (mpMRI) before confirmatory prostate biopsy in patients under active surveillance (AS). Materials and Methods: This retrospective study included 170 patients with Gleason grade 6 prostate cancer initially enrolled in an AS program between 2011 and 2019. Prostate mpMRI was performed using a 1.5 tesla (T) magnetic resonance imaging system with a 16-channel phased-array body coil. The protocol included T1-weighted, T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging sequences. Uroradiology reports generated by a specialist were based on prostate imagingreporting and data system (PI-RADS) version 2. Univariate and multivariate analyses were performed based on regression models. Results: The reclassification rate at confirmatory biopsy was higher in patients with suspicious lesions on mpMRI (PI-RADS score ≥ 3) (n = 47) than in patients with non-suspicious mpMRIs (n = 61) and who did not undergo mpMRIs (n = 62) (66%, 26.2%, and 24.2%, respectively; p < 0.001). On multivariate analysis, presence of a suspicious mpMRI finding (PI-RADS score ≥ 3) was associated (adjusted odds ratio: 4.72) with the risk of reclassification at confirmatory biopsy after adjusting for the main variables (age, prostate-specific antigen density, number of positive cores, number of previous biopsies, and clinical stage). Presence of a suspicious mpMRI finding (adjusted hazard ratio: 2.62) was also associated with the risk of progression to active treatment during the follow-up. Conclusion: Inclusion of mpMRI before the confirmatory biopsy is useful to stratify the risk of reclassification during the biopsy as well as to evaluate the risk of progression to active treatment during follow-up.

Performance modelling of single and double absorption heat transformers

Rosa María Barragán Reyes,Víctor Manuel Arellano Gómez,Alfonso García-Gutiérrez 한국물리학회 2010 Current Applied Physics Vol.10 No.2

Absorption heat transformers (heat pump Type II) enable the temperature of a low heat source to be raised to a higher level. This process takes place by means of the absorption of a vaporized working fluid into a substance which has strong affinity for the vapor. The temperature lift and the coefficient of performance (a measure of the efficiency of the process), are important design parameters which depend on the thermodynamic properties of the working pair and also on the configuration of the equipment. In order to investigate the performance of readily available, not expensive and environmentally friendly fluids in heat transformers, the systems H2O/CaCl2 and H2O/LiCl were studied, by using a Fortran program. The theoretical performance of both systems in a single stage absorption heat transformer (SSHT), was derived and compared to results obtained previously for the system H2O/CaCl2 on a double absorption unit (DAHT).

First Record of the Pacific Fanfish Pteraclis aesticola (Jordan and Snyder, 1901) in the Tropical Eastern Pacific

José De La Cruz Agüero,Víctor Manuel Cota Gómez 한국해양과학기술원 2008 Ocean science journal Vol.43 No.3

One specimen of Pteraclis aesticola was collected off San José del Cabo, Baja California Sur, México (22°54'N, 109°45'W), in March 2007. Present record is the first reported occurrence of the species in the Tropical Eastern Pacific biogeographic region (Gulf of California to southern Ecuadorian waters). Its large fan-like anal and dorsal fins and its counts of fin rays and vertebrae can distinguish the Pacific fanfish from the other species in the genus. This fish may have not yet been recorded in the region because its presence has been overlooked in the past because of rarity and lack of commercial value. One specimen of Pteraclis aesticola was collected off San José del Cabo, Baja California Sur, México (22°54'N, 109°45'W), in March 2007. Present record is the first reported occurrence of the species in the Tropical Eastern Pacific biogeographic region (Gulf of California to southern Ecuadorian waters). Its large fan-like anal and dorsal fins and its counts of fin rays and vertebrae can distinguish the Pacific fanfish from the other species in the genus. This fish may have not yet been recorded in the region because its presence has been overlooked in the past because of rarity and lack of commercial value.

Morphometric and Molecular Data on Two Mitochondrial Genes of a Newly Discovered Chimaeran Fish (Hydrolagus melanophasma, Chondrichthyes)

José De La Cruz-Agüero,Francisco Javier García-Rodríguez,Víctor Manuel Cota-Gómez,Felipe Neri Melo-Barrera,Rogelio González-Armas 한국해양과학기술원 2012 Ocean science journal Vol.47 No.2

Fresh and preserved (type material) specimens of the black ghost chimaera Hydrolagus melanophasma were compared for morphometric characteristics. A molecular comparison was also performed on two mitochondrial gene sequences (12S rRNA and 16S rRNA gene sequences). While significant differences in measurements were found, the differences were not attributable to sexual dimorphism or the quality of the specimens, but to the sample size and the type of statistical tests. The result of the genetic characterization showed that 12S rRNA and 16S rRNA genes represented robust molecular markers that characterized the species.

Effectiveness of Thrombectomy in Stroke According to Baseline Prognostic Factors: Inverse Probability of Treatment Weighting Analysis of a Population- Based Registry

Salvatore Rudilosso,José Ríos,Alejandro Rodríguez,Meritxell Gomis,Víctor Vera,Manuel Gómez-Choco,Arturo Renú,Núria Matos,Laura Llull,Francisco Purroy,Sergio Amaro,Mikel Terceño,Víctor Obach,Joaquim Se 대한뇌졸중학회 2021 Journal of stroke Vol.23 No.3

Background and Purpose In real-world practice, the benefit of mechanical thrombectomy (MT) is uncertain in stroke patients with very favorable or poor prognostic profiles at baseline. We studied the effectiveness of MT versus medical treatment stratifying by different baseline prognostic factors. Methods Retrospective analysis of 2,588 patients with an ischemic stroke due to large vessel occlusion nested in the population-based registry of stroke code activations in Catalonia from January 2017 to June 2019. The effect of MT on good functional outcome (modified Rankin Score ≤2) and survival at 3 months was studied using inverse probability of treatment weighting (IPTW) analysis in three pre-defined baseline prognostic groups: poor (if pre-stroke disability, age >85 years, National Institutes of Health Stroke Scale [NIHSS] >25, time from onset >6 hours, Alberta Stroke Program Early CT Score <6, proximal vertebrobasilar occlusion, supratherapeutic international normalized ratio >3), good (if NIHSS <6 or distal occlusion, in the absence of poor prognostic factors), or reference (not meeting other groups’ criteria). Results Patients receiving MT (n=1,996, 77%) were younger, had less pre-stroke disability, and received systemic thrombolysis less frequently. These differences were balanced after the IPTW stratified by prognosis. MT was associated with good functional outcome in the reference (odds ratio [OR], 2.9; 95% confidence interval [CI], 2.0 to 4.4), and especially in the poor baseline prognostic stratum (OR, 3.9; 95% CI, 2.6 to 5.9), but not in the good prognostic stratum. MT was associated with survival only in the poor prognostic stratum (OR, 2.6; 95% CI, 2.0 to 3.3). Conclusions Despite their worse overall outcomes, the impact of thrombectomy over medical management was more substantial in patients with poorer baseline prognostic factors than patients with good prognostic factors.