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Abstract The production of green hydrogen in water electrolyzers is limited by the oxygen evolution reaction (OER). State-of-the-art electrocatalysts are based on Ir. Ru electrocatalysts are a suitable alternative provided their performance is improved. Here we show that low-Ru-content pyrochlores (R2MnRuO7, R = Y, Tb and Dy) display high activity and durability for the OER in acidic media. Y2MnRuO7 is the most stable catalyst, displaying 1.5 V at 10 mA cm−2 for 40 h, or 5000 cycles up to 1.7 V. Computational and experimental results show that the high performance is owed to Ru sites embedded in RuMnOx surface layers. A water electrolyser with Y2MnRuO7 (with only 0.2 mgRu cm−2) reaches 1 A cm−2 at 1.75 V, remaining stable at 200 mA cm−2 for more than 24 h. These results encourage further investigation on Ru catalysts in which a partial replacement of Ru by inexpensive cations can enhance the OER performance.

Here, the authors investigate the aboveground carbon sink efficiency of Andean forests. The study shows the high potential of these forests to serve as future carbon refuges, and urges to reduce deforestation and increase restoration.

Traffic accidents leave lifelong after-effects and if the victim is disabled, they produce a production loss due to the differential in income that will be lost. This average value is very divergent in European countries, although there is consensus on cost components and valuation methods. However, many countries have legally standardised financial compensation so that it is calculated objectively and equitably for all those affected. This paper sets out the procedure for standardising the lost production cost of incapacitated road accident victims. An actuarial methodology relating to known inputs (age and salary) is used to obtain economic compensation for lost productivity. General principles and hypotheses are provided, and cases that require particular valuation are located. The standard cost thus calculated allows a homogeneous, fair and equitable compensation for all those involved in similar circumstances.

While water splitting may afford a renewable means to store energy in chemical bonds, water oxidation catalysts suffer from poor stabilities in acidic media. Here, authors show sodium doping of strontium ruthenate to improve the catalytic durability while maintaining a high O2 evolution activity.

Natural killer T (NKT) cells constitute a unique subset of T lymphocytes characterized by specifically interacting with antigenic glycolipids conjugated to the CD1d receptor on antigen-presenting cells. Functionally, NKT cells are capable of performing either effector or suppressor immune responses, depending on their production of proinflammatory or anti-inflammatory cytokines, respectively. Effector NKT cells are subdivided into three subsets, termed NKT1, NKT2, and NKT17, based on the cytokines they produce and their similarity to the cytokine profile produced by Th1, Th2, and Th17 lymphocytes, respectively. Recently, a new subgroup of NKT cells termed NKT10 has been described, which cooperates and interacts with other immune cells to promote immunoregulatory responses. Although the tissue-specific functions of NKT cells have not been fully elucidated, their activity has been associated with the pathogenesis of different inflammatory diseases with immunopathogenic similarities to periodontitis, including osteolytic pathologies such as rheumatoid arthritis and osteoporosis. In the present review, we revise and discuss the pathogenic characteristics of NKT cells in these diseases and their role in the pathogenesis of periodontitis; particularly, we analyze the potential regulatory role of the IL-10-producing NKT10 cells.

In this work, we study the direct synthesis of DME using CO2-rich syngas, with a CO2/CO ratio similar to that obtained from the gasification of biomass, i.e., 1.9. We used catalytic beds consisting of physical mixtures of the benchmark catalysts used for the synthesis of methanol from syngas and for methanol dehydration to DME, namely Cu/ZnO/Al2O3 and γ-Al2O3, respectively. Our results show that the ratio between each catalytic phase determines the productivity and selectivity to DME, as well CO and CO2 conversions. Thus, higher total carbon conversions were obtained with the catalytic bed with the highest content of the Cu/Zn/Al2O3 phase. The presence of γ-Al2O3 allows to exceed the equilibrium conversion of CO for the syngas to methanol synthesis. The highest DME productivity is obtained with the catalytic bed containing equal amounts of both catalytic phases. In addition, we also show that other reaction variables such as temperature, pressure, and contact time also play an important role in terms of DME productivity. The presence of a high fraction of CO2 in the syngas results in a high production of H2O, which after long times on stream result in the deactivation of the Cu/ZnO/Al2O3 catalytic phase due to the sintering of the copper particles. The in situ removal of H2O via the addition of an H2O sorbent, zeolite 3A, into the catalytic bed, results in a significant enhancement of both carbon conversion and DME productivity.

The synthesis of methanol from biomass-derived syngas can be challenging because of the high CO2 content in the bio-syngas, resulting in lower kinetics and higher catalyst deactivation. This work explores the in situ pre-treatment of a CO2-rich syngas with a CO2/CO ratio equal to 1.9 through the reverse-water gas shift reaction with the aim of adjusting this ratio to a more favorable one for the synthesis of methanol with Cu-based catalysts. Both reactions take place in two catalytic beds placed in the same reactor, thus intensifying the methanol process. The water produced during syngas conditioning is removed by means of a sorbent zeolite to prevent the methanol catalyst deactivation and to shift the equilibrium towards the methanol formation. The combination of the CO2 shifting and the water sorption strategies lead to higher productivities of the catalytic bed and, under certain reaction conditions, to higher methanol productions.

The reasons for the strong rise in the securitization phenomenon up until the start of the “subprime crisis” need to be analysed. According to many authors, they mainly stem from its offering the possibility of generating fixed yield securities with the highest rating and a low risk premium, thanks to the issues being structured in differentiated bond series, so that certain series absorb most of the risk, thus facilitating the safer or “senior” tranches having a higher rating. Accordingly, this paper reviews the literature on the factors underlying the generation of differentiated tranches in this type of issues and regarding the determining factors of the yield offered by securitization issues. It concludes that the search for more complete markets, along with the reducing of problems associated to the moral hazard, are the main reasons for the multi-tranche structuring. And given the strong influence of the number of tranches on the yield offered by the issues, the paper likewise concludes that the multitranche structures has been an efficient tool to place securitization issues with more competitive yields.

Debt issue credit ratings can lead to conflicts of interest as the issuer itself is entrusted with contracting and compensating the rating agency. Into the bargain, the credit rating agency may be involved in designing the issues that the same agency subsequently rates. Credit rating agencies thus could have incentives to rate issues advantageously. Given the economic importance of this issue, in this paper we have proposed to analyze this phenomenon, known as rating shopping in academic literature, for Spanish market securitization issues for the period of time comprehensive from January 1993 to December 2011. In sum 3,665 published ratings are been analysed, for an issued nominal amount of 791,090 million Euros. The results show an association between the credit rating agency contracted and the mean rating awarded. Significant differences are observed in the ratings associated to the contracting manager (or special purpose vehicle SPV- manager firm), to the number of ratings or to the type of collateral. Furthermore, a pattern compatible with rating shopping was observed for some types of collateral: abnormally high market shares associated with certain agencies awarding unusually generous ratings. However, this phenomenon is not seen to be widespread on the rating market associated to Spanish securitization issues.

Este artículo analiza los determinantes de la rentabilidad primaria de los bonos de titulización hipotecaria (conocidos en la literatura como mortgage backed securities, o MBS) emitidos en España durante el periodo 1993-2011, periodo en el que el mercado español llegó a convertirse en el más importante de Europa continental. Los resultados obtenidos sobre el análisis de la población completa de MBS emitidos (262 tramos configurados sobre 94 fondos de titulización) indican que la estructuración multitramo de los MBS ha ayudado a reducir el riesgo percibido global de las emisiones de MBS, mediante la generación de mercados más completos y la reducción de los problemas derivados de la existencia de asimetrías informativas implícitas en el proceso de selección de los activos transmitidos por parte de la entidad cedente. Esta reducción del riesgo percibido ha tenido un efecto directo sobre la rentabilidad ofrecida por los bonos de titulización emitidos. Además, no se encuentran evidencias de que la emisión de MBS persiga la transmisión efectiva de riesgos, más bien al contrario. Las entidades de crédito, por lo general, han retenido los tramos de primeras pérdidas, lo que ha contribuido a mantener en niveles muy bajos (por debajo de la rentabilidad de la deuda soberana) la rentabilidad ofrecida por los MBS. Precisamente, el escaso diferencial ofrecido por los bonos de titulización se debe a que los tramos retenidos no han ofrecido primas de rentabilidad ajustadas al riesgo inherente.

The review article discusses the current status and recent findings of our investigations on the synthesis and characterization of carbon-supported PtRuMo electrocatalysts for direct alcohol fuel cells. In particular, the effect of the carbon support and the composition on the structure, stability and the activity of the PtRuMo nanoparticles for the electrooxidation of CO, methanol and ethanol have been studied. Different physicochemical techniques have been employed for the analysis of the catalysts structures: X-ray analytical methods (XRD, XPS, TXRF), thermogravimetry (TGA) and transmission electron microscopy (TEM), as well as a number of electrochemical techniques like CO adsorption studies, current-time curves and cyclic voltammetry measurements. Furthermore, spectroscopic methods adapted to the electrochemical systems for in situ studies, such as Fourier transform infrared spectroscopy (FTIRS) and differential electrochemical mass spectrometry (DEMS), have been used to evaluate the oxidation process of CO, methanol and ethanol over the carbon-supported PtRuMo electrocatalysts.

En el Oriente antioqueño (Antioquia), Colombia, en tierras utilizadas previamente en ganadería extensiva, se estudió la sucesión secundaria analizando la densidad arbórea, área basal y biomasa aérea. Se evaluaron seis fragmentos de bosque, agrupados en dos categorías de edad: bosques secundarios (BS) de 15 a 20 años y BS de 25 a 30 años. La recuperación de los BS fue comparada con respecto a información secundaria de bosques maduros (BM). Entre los BS y el BM se encontraron diferencias significativas en el promedio por hectárea de la biomasa aérea y el área basal, pero no en la densidad de individuos con respecto a la edad después del abandono. Se estimó que los bosques secundarios entre 25 a 30 años con respecto al BM recuperaron el área basal en un 85,2% y la biomasa aérea en un 52,7%. En toda el área estudiada la acumulación de biomasa aérea promedio anual en el 2005 fue de 4,6 ± 0,3 t ha-1 año-1 que corresponde a un total de 323.469,8 ± 23.227,7 toneladas (t), equivalentes a 161.734,88 ± 11.613,65 t carbono secuestrado (C). Los resultados confirman el manejo de la regeneración natural como estrategia viable y de bajo costo para lograr la recuperación de la estructura de los bosques degradados en el área de estudio. Igualmente, se ratifica la alta productividad primaria neta de los ecosistemas boscosos sucesionales y su aporte a la regulación del ciclo global del carbono.We studied secondary forest succession of areas in eastern Antioquia, Colombia that were previously used for cattle ranching by analyzing tree density, basal area and aboveground biomass. Six forest patches in two age categories were investigated: Secondary forest (BS) that was 15 to 20 years old, and BS that was 25 to 30 years old. BS recovery was compared to secondary information from mature forest (BM). The BS and BM presented significant differences between the mean above ground biomass and basal area, but not in tree density as a function of years since abandonment. 25 to 30 year old secondary forests had recovered an estimated 85.2% of basal area and 52.7% of aboveground biomass with respect to those of BM. Over the entire area studied, mean annual accumulation of aboveground biomass in the forest patches in 2005 was 4.6 ± 0.3 t ha-1 per year, which represented a total of 323,469.8 ± 23,227.3 t, equivalent to 161,734.88 ± 11,613.65 t of carbon storage (C). These results confirm that management of natural regeneration is a viable, low cost strategy for the recovery of forest structure in this study area. Also, they demonstrate the high net primary productivity of this successional forest ecosystem and its contribution to the global carbon cycle.

El presente estudio analizó la magnitud a la cual la variación ambiental y las variables espaciales influencian la distribución de las especies arbóreas de dosel (DAP ≥ 10 cm), a escala local en un bosque de tierra firme de la Amazonia colombiana. El muestreo se llevó a cabo en una parcela de cinco ha, dividida en 125 cuadrantes de 20 x 20 m, ubicada en el PNN Amacayacu. Se seleccionaron las especies con una frecuencia igual o mayor a diez (10) en los 125 cuadrantes. Para cuantificar el efecto del ambiente y el espacio geográfico, se empleó la regresión logística con base en los datos de presencia ausencia de las especies en cada uno de los cuadrantes. La distribución de las especies presentó mayor relación con las variables espaciales que con las ambientales, permaneciendo generalmente en promedio el 50,7 ± 23,8% de desviación sin explicar. Las variables ambientales fueron significativas en 33 modelos, presentando capacidad explicativa entre 0,21 y 23,71%. Las variables espaciales fueron incluidas en todos los modelos explicativos de la distribución de las especies, con una importancia relativa de hasta el 97,3%. El presente estudio, resalta la importancia del análisis de las respuestas de especies arbóreas individuales a los cambios ambientales y espaciales, encontrando diferencias en los factores que determinan la distribución de especies dentro de familias e incluso dentro de un mismo género, lo cual tiene gran influencia en la estructuración de la diversidad alpha. Lo que esto demuestra es que la especialización de hábitat y los procesos espacialmente estructurados como la limitación en dispersión, más que ser mecanismos excluyentes, actúan de forma complementaria a diferentes niveles promoviendo la coexistencia de especies. Los resultados obtenidos difieren de estudios anteriores en cuanto que este estudio muestra menor importancia relativa de los factores edáficos sobre la distribución de especies a escala local. En este caso particular, se sugiere que a escala local existe un alto componente aleatorio asociado con la variación no explicada. Sin embargo, no se descarta que esta condición emerja como producto del submuestreo en estos bosques de diversidad muy alta.In this study, we analyzed the extent to which environmental variation and the spatial template influenced the distribution of individual canopy species (DBH ≥ 10 cm) at a local scale in terra firme forest in the Colombian Amazonia. The survey was carried out in a 5-ha plot, divided into 125 quadrants of 20 m x 20 m, located in the Amacayacu National Park. To run the analyses we selected all species with presence in ten or more quadrants. In order to quantify the effect of the environment and geographical space, we used a logistic regression model, which was based on species presence-absence data for the selected species. Species distributions showed a higher correlation with the spatial variables than with the environmental ones, with an average of 50.7 ± 23.8% of unexplained variation remaining. Environmental variables were significant in 33 out of 45 models, ranging in relative importance between 0.21 and 23.71%. All explanatory models of species distributions included spatial variables, which reached a relative importance of up to 97.3%. We found differences in the factors determining the distribution of individual species within the same family and even within the same genera, which helped to understand the key factors structuring alpha diversity. In this way, our results support the idea that environmental filtering and spatially structured processes, such us dispersal limitation, are complementary rather than exclusive mechanisms promoting species coexistence. The results obtained in this study showed a relatively lower importance of soils and topography on species distribution, at a local spatial scale, than reported before. In this case study, we found a high random component related to the unexplained variation; however, it was also necessary to emphasize the effect of species undersampling on the unexplained variation, due to the high local diversity recorded in this forest.

Introduction: Reducing Optic Atrophy 1 (OPA1) expression in skeletal muscle in male mice induces Activation Transcription Factor 4 (ATF4) and the integrated stress response (ISR). Additionally, skeletal muscle secretion of Fibroblast Growth Factor 21 (FGF21) is increased, which mediates metabolic adaptations including resistance to diet-induced obesity (DIO) and glucose intolerance in these mice. Although FGF21 induction in this model can be reversed with pharmacological attenuation of ER stress, it remains to be determined if ATF4 is responsible for FGF21 induction and its metabolic benefits in this model. Methods: We generated mice with homozygous floxed Opa1 and Atf4 alleles and a tamoxifen-inducible Cre transgene controlled by the human skeletal actin promoter to enable simultaneous depletion of OPA1 and ATF4 in skeletal muscle (mAO DKO). Mice were fed high fat (HFD) or control diet and evaluated for ISR activation, body mass, fat mass, glucose tolerance, insulin tolerance and circulating concentrations of FGF21 and growth differentiation factor 15 (GDF15). Results: In mAO DKO mice, ATF4 induction is absent. Other indices of ISR activation, including XBP1s, ATF6, and CHOP were induced in mAO DKO males, but not in mOPA1 or mAO DKO females. Resistance to diet-induced obesity was not reversed in mAO DKO mice of both sexes. Circulating FGF21 and GDF15 illustrated sexually dimorphic patterns. Loss of OPA1 in skeletal muscle increases circulating FGF21 in mOPA1 males, but not in mOPA1 females. Additional loss of ATF4 decreased circulating FGF21 in mAO DKO male mice, but increased circulating FGF21 in female mAO DKO mice. Conversely, circulating GDF15 was increased in mAO DKO males and mOPA1 females, but not in mAO DKO females. Conclusion: Sex differences exist in the transcriptional outputs of the ISR following OPA deletion in skeletal muscle. Deletion of ATF4 in male and female OPA1 KO mice does not reverse the resistance to DIO. Induction of circulating FGF21 is ATF4 dependent in males, whereas induction of circulating GDF15 is ATF4 dependent in females. Elevated GDF15 in males and FGF21 in females could reflect activation by other transcriptional outputs of the ISR, that maintain mitokine-dependent metabolic protection in an ATF4- independent manner. [ABSTRACT FROM AUTHOR]

Corn plays a fundamental role in the diet of diverse cultures and has nutritional benefits, being a rich source of carbohydrates, fiber, vitamins and minerals, in addition to containing antioxidants with health properties. In places like Peru and Latin America, where corn production and commercialization are significant for various culinary uses (patasca, tamales, humitas, among others), there is a need to industrialize the peeling process to speed up production and advance technologically, overcoming the manual method disadvantages. Therefore, this research aimed to design and manufacture a precooked corn peeling machine based on the friction of corn with a rough surface, through the incorporation of adjustable paddles and constant flow of clean water to remove impurities, in order to obtain larger quantities of peeled corn production, being able to supply the local market. To design the machine, the VDI 2221 methodology was applied, which included the creation of a list of requirements and a function structure. The state of the art corn shelling technology was evaluated using techniques such as the black box, white box and morphological matrix approach to analyze solution options. Design aspects such as shaft diameter, vane strength, cylinder volume, drive belt selection, number of belts and bearing choice were considered. Finally, manufacturing materials were selected. The design of the corn peeling machine was obtained. In addition, data on peeling speed and amount of corn peeling were found through washing tests using different corn grains. It was found that the optimum time is 7 minutes, which considerably improves the artisanal method, which requires more time and physical effort by the producer and for the manufacture of the machine, non-polluting materials will be used for corn, such as stainless steel AISI 304, which does not corrode in contact with water. It was concluded that, with the design of a corn pericarp peeling machine gave a 96.3% efficiency in the peeling process, which shows that it is possible to peel corn for health care, also for use in different gastronomic dishes. In addition, the manufacture of the machine is possible since the materials used can be easily found in the local market and have low costs. [ABSTRACT FROM AUTHOR]

El presente artículo se precisan los principales conceptos relacionados con la táctica en el kumite del karate do categoría escolar, por consiguiente, va dirigido hacia el estudio de la preparación táctica, específicamente hacia la determinación de las acciones o fases de la táctica, así como los diferentes métodos de la preparación táctica, sus y pensamiento táctico; el análisis de los principios para la evaluación de la táctica en los deportes de oposición y la concepción de los diferentes tipos de kumite en el karate-do, como aspectos más complejos de la preparación del karateca, lo cual constituye de gran importancia. para el mismo fue necesario el empleo de varios métodos de investigación entre ellos el análisis síntesis el cual permite analizar la literatura consultada y llegar a consideraciones sobre el tema de igual manera el empleo de la inducción deducción permitió arribar a conclusiones.

Adrenergic stimulation of brown adipocytes alters mitochondrial dynamics, including the mitochondrial fusion protein optic atrophy 1 (OPA1). However, direct mechanisms linking OPA1 to brown adipose tissue (BAT) physiology are incompletely understood. We utilized a mouse model of selective OPA1 deletion in BAT (OPA1 BAT KO) to investigate the role of OPA1 in thermogenesis. OPA1 is required for cold-induced activation of thermogenic genes in BAT. Unexpectedly, OPA1 deficiency induced fibroblast growth factor 21 (FGF21) as a BATokine in an activating transcription factor 4 (ATF4)-dependent manner. BAT-derived FGF21 mediates an adaptive response by inducing browning of white adipose tissue, increasing resting metabolic rates, and improving thermoregulation. However, mechanisms independent of FGF21, but dependent on ATF4 induction, promote resistance to diet-induced obesity in OPA1 BAT KO mice. These findings uncover a homeostatic mechanism of BAT-mediated metabolic protection governed in part by an ATF4-FGF21 axis, which is activated independently of BAT thermogenic function.

The fetal autonomic nervous system responds to uterine contractions during active labor as identified by changes in the accelerations and decelerations of fetal heart rate (FHR). Thus, this exploratory study aimed to characterize the asymmetry differences of beat-to-beat FHR accelerations and decelerations in preterm and term fetuses during active labor. In an observational study, we analyzed 10 min of fetal R-R series collected from women during active preterm labor (32–36 weeks of pregnancy, n = 17) and active term labor (38–40 weeks of pregnancy, n = 27). These data were used to calculate the Deceleration Reserve (DR), which is a novel parameter that quantifies the asymmetry of the average acceleration and deceleration capacity of the heart. In addition, relevant multiscale asymmetric indices of FHR were also computed. Lower values of DR, calculated with the input parameters of T = 50 and s = 10, were associated with labor occurring at the preterm condition (p = 0.0131). Multiscale asymmetry indices also confirmed significant (p < 0.05) differences in the asymmetry of FHR. Fetuses during moderate premature labor may experience more decaying R-R trends and a lower magnitude of decelerations compared to term fetuses. These differences of FHR dynamics might be related to the immaturity of the fetal cardiac autonomic nervous system as identified by this system response to the intense uterine activity at active labor.

We previously reported that mice lacking the protein optic atrophy 1 (OPA1 BKO) in brown adipose tissue (BAT) display induction of the activating transcription factor 4 (ATF4), which promotes fibroblast growth factor 21 (FGF21) secretion as a batokine. FGF21 increases metabolic rates under baseline conditions but is dispensable for the resistance to diet-induced obesity (DIO) reported in OPA1 BKO mice (Pereira et al., 2021). To determine alternative mediators of this phenotype, we performed transcriptome analysis, which revealed increased levels of growth differentiation factor 15 (GDF15), along with increased protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) levels in BAT. To investigate whether ATF4 induction was mediated by PERK and evaluate the contribution of GDF15 to the resistance to DIO, we selectively deleted PERK or GDF15 in OPA1 BKO mice. Mice with reduced OPA1 and PERK levels in BAT had preserved ISR activation. Importantly, simultaneous deletion of OPA1 and GDF15 partially reversed the resistance to DIO and abrogated the improvements in glucose tolerance. Furthermore, GDF15 was required to improve cold-induced thermogenesis in OPA1 BKO mice. Taken together, our data indicate that PERK is dispensable to induce the ISR, but GDF15 contributes to the resistance to DIO, and is required for glucose homeostasis and thermoregulation in OPA1 BKO mice by increasing energy expenditure. [ABSTRACT FROM AUTHOR]

Various models of mitochondrial stress result in induction of the stressresponsive cytokines fibroblast growth factor 21 (FGF21) and growth differentiation factor 15 (GDF15). This is an adaptive mechanism downstream of the mitochondrial integrated stress response frequently associated with improvements in systemic metabolic health. Both FGF21 and GDF15 have been shown to modulate energy balance and glucose homeostasis, and their pharmacological administration leads to promising beneficial effects against obesity and associated metabolic diseases in pre-clinical models. Furthermore, endogenous upregulation of FGF21 and GDF15 is associated with resistance to diet-induced obesity (DIO), improved glucose homeostasis and increased insulin sensitivity. In this review, we highlight several studies on transgenic mouse models of mitochondrial stress and will compare the specific roles played by FGF21 and GDF15 on the systemic metabolic adaptations reported in these models. [ABSTRACT FROM AUTHOR]

Phase Entropy (PhEn) was recently introduced for evaluating the nonlinear features of physiological time series. PhEn has been demonstrated to be a robust approach in comparison to other entropy-based methods to achieve this goal. In this context, the present study aimed to analyze the nonlinear features of raw electrohysterogram (EHG) time series collected from women at the third trimester of pregnancy (TT) and later during term active parturition (P) by PhEn. We collected 10-min longitudinal transabdominal recordings of 24 low-risk pregnant women at TT (from 35 to 38 weeks of pregnancy) and P (>39 weeks of pregnancy). We computed the second-order difference plots (SODPs) for the TT and P stages, and we evaluated the PhEn by modifying the k value, a coarse-graining parameter. Our results pointed out that PhEn in TT is characterized by a higher likelihood of manifesting nonlinear dynamics compared to the P condition. However, both conditions maintain percentages of nonlinear series higher than 66%. We conclude that the nonlinear features appear to be retained for both stages of pregnancy despite the uterine and cervical reorganization process that occurs in the transition from the third trimester to parturition.

Liver is an essential organ that carries out multiple functions such as glycogen storage, the synthesis of plasma proteins, and the detoxification of xenobiotics. Hepatocytes are the parenchyma that sustain almost all the functions supported by this organ. Hepatocytes and non-parenchymal cells respond to the mechanical alterations that occur in the extracellular matrix (ECM) caused by organogenesis and regenerating processes. Rearrangements of the ECM modify the composition and mechanical properties that result in specific dedifferentiation programs inside the hepatic cells. Quiescent hepatocytes are embedded in the soft ECM, which contains an important concentration of fibrillar collagens in combination with a basement membrane-associated matrix (BM). This work aims to evaluate the role of fibrillar collagens and BM on actin cytoskeleton organization and the function of rat primary hepatocytes cultured on soft elastic polyacrylamide hydrogels (PAA HGs). We used rat tail collagen type I and Matrigel® as references of fibrillar collagens and BM respectively and mixed different percentages of collagen type I in combination with BM. We also used peptides obtained from decellularized liver matrices (dECM). Remarkably, hepatocytes showed a poor adhesion in the absence of collagen on soft PAA HGs. We demonstrated that collagen type I inhibited apoptosis and activated extracellular signal-regulated kinases 1/2 (ERK1/2) in primary hepatocytes cultured on soft hydrogels. Epidermal growth factor (EGF) was not able to rescue cell viability in conjugated BM but affected cell aggregation in soft PAA HGs conjugated with combinations of different proportions of collagen and BM. Interestingly, actin cytoskeleton was localized and preserved close to plasma membrane (cortical actin) and proximal to intercellular ducts (canaliculi-like structures) in soft conditions; however, albumin protein expression was not preserved, even though primary hepatocytes did not remodel their actin cytoskeleton significantly in soft conditions. This investigation highlights the important role of fibrillar collagens on soft hydrogels for the maintenance of survival and aggregation of the hepatocytes. Data suggest evaluating the conditions that allow the establishment of optimal biomimetic environments for physiology and cell biology studies, where the phenotype of primary cells may be preserved for longer periods of time.