Engineering physiological environments to advance kidney organoid models from human pluripotent stem cells

During embryogenesis, the mammalian kidney arises because of reciprocal interactions between the ureteric bud (UB) and the metanephric mesenchyme (MM), driving UB branching and nephron induction. These morphogenetic processes involve a series of cellular rearrangements that are tightly controlled by gene regulatory networks and signaling cascades. Here, we discuss how kidney developmental studies have informed the definition of procedures to obtain kidney organoids from human pluripotent stem cells (hPSCs). Moreover, bioengineering techniques have emerged as potential solutions to externally impose controlled microenvironments for organoid generation from hPSCs. Next, we summarize some of these advances with major focus On recent works merging hPSC-derived kidney organoids (hPSC-kidney organoids) with organ-on-chip to develop robust models for drug discovery and disease modeling applications. We foresee that, in the near future, coupling of different organoid models through bioengineering approaches will help advancing to recreate organ-to-organ crosstalk to increase our understanding on kidney disease progression in the human context and search for new therapeutics

Adquisición de competencias en la atención al parto normal durante la formación de la especialidad de matrona: prácticas simuladas para la reparación de episiotomías y desgarros perineales en la atención al parto normal. Parte II

Se describen las actividades que realizan las matronas residentes en la Unidad Docente de Matronas de Cataluña (UDMC) para la adquisición de competencias en la reparación de episiotomías y desgarros perineales en la atención al parto normal

Seasonal patterns of pollen sedimentation in Lake Montcortès (Central Pyrenees) and potential applications to high-resolution paleoecology: a 2-year pilot study

14 páginas, 2 tablas, 10 figuras.Lakes with varved sediments are especially well suited for paleoecological study, from annual to even seasonal resolution. The interpretative power of such high-resolution paleoenvironmental reconstructions relies on the availability of modern analogs with the same temporal resolution. We studied seasonal pollen sedimentation in varved Lake Montcorte`s, Central Pyrenees (Spain), as a modern analog for highresolution reconstruction of Late Holocene vegetation and landscape dynamics. Seasonal samples were obtained from sediment traps that were submerged near the maximum water depth for a 2-year period (fall 2013 to fall 2015). Seasonal pollen sedimentation was compared with meteorological variables from a nearby weather station. Bulk pollen sedimentation, dominated by Pinus (pine) and Quercus (oak), followed a clear seasonal pattern that peaked during the spring/summer, coinciding with maximum temperature and precipitation, minimum relative humidity and moderate winds from the SSE. Pollen sedimentation lags (PSL) were observed formost pollen types, as substantial amounts of pollen were found in the traps outside of their respective flowering seasons. Two pollen assemblages were clearly differentiated by their taxonomic composition, corresponding to spring/summer and fall/winter. This pattern is consistent with existing interpretation of the sediment varves, specifically, that varves are formed by two-layer couplets that represent the same seasonality as pollen. We concluded that pollen sedimentation in Lake Montcorte`s exhibits a strong seasonal signal in the quantity of pollen, the taxonomic composition of the pollen assembalges, and relationships between the pollen and meteorological variables. Thus, varved sediments provide a potentially powerful tool for paleoecological reconstruction at seasonal resolution. This method could be used not only to identify paleoenvironmental trends, but also to identify annual layers and therefore date sediments, even in the absence of evident sediment laminations. A satisfactory explanation of PSL will require further studies that examine internal lake dynamics and pollen production/dispersal patterns.This work was funded by the Ministry of Economy and Competitivity (project MONT-500; reference CGL2012-33665; PI: Teresa Vegas-Vilarru´bia).Peer reviewe

Breakdown of the mean-field approximation in a wealth distribution model

One of the key socioeconomic phenomena to explain is the distribution of wealth. Bouchaud and M\'ezard have proposed an interesting model of economy [Bouchaud and M\'ezard (2000)] based on trade and investments of agents. In the mean-field approximation, the model produces a stationary wealth distribution with a power-law tail. In this paper we examine characteristic time scales of the model and show that for any finite number of agents, the validity of the mean-field result is time-limited and the model in fact has no stationary wealth distribution. Further analysis suggests that for heterogeneous agents, the limitations are even stronger. We conclude with general implications of the presented results.Comment: 11 pages, 3 figure

Seasonal patterns of pollen sedimentation in Lake Montcortès (Central Pyrenees) and potential applications to high-resolution paleoecology: a two-year pilot study.

Lakes with varved sediments are especially well suited for paleoecological study, from annual to even seasonal resolution. The interpretative power of such high-resolution paleoenvironmental reconstructions relies on the availability of modern analogs with the same temporal resolution. We studied seasonal pollen sedimentation in varved Lake Montcorte`s, Central Pyrenees (Spain), as a modern analog for highresolution reconstruction of Late Holocene vegetation and landscape dynamics. Seasonal samples were obtained from sediment traps that were submerged near the maximum water depth for a 2-year period (fall 2013 to fall 2015). Seasonal pollen sedimentation was compared with meteorological variables from a nearby weather station. Bulk pollen sedimentation, dominated by Pinus (pine) and Quercus (oak), followed a clear seasonal pattern that peaked during the spring/summer, coinciding with maximum temperature and precipitation, minimum relative humidity and moderate winds from the SSE. Pollen sedimentation lags (PSL) were observed for most pollen types, as substantial amounts of pollen were found in the traps outside of their respective flowering seasons. Two pollen assemblages were clearly differentiated by their taxonomic composition, corresponding to spring/summer and fall/winter. This pattern is consistent with existing interpretation of the sediment varves, specifically, that varves are formed by two-layer couplets that represent the same seasonality as pollen. We concluded that pollen sedimentation in Lake Montcorte`s exhibits a strong seasonal signal in the quantity of pollen, the taxonomic composition of the pollen assembalges, and relationships between the pollen and meteorological variables. Thus, varved sediments provide a potentially powerful tool for paleoecological reconstruction at seasonal resolution. This method could be used not only to identify paleoenvironmental trends, but also to identify annual layers and therefore date sediments, even in the absence of evident sediment laminations. A satisfactory explanation of PSL will require further studies that examine internal lake dynamics and pollen production/dispersal patterns

Glycoprotein profile assessed by1h-nmr as a global inflammation marker in patients with HIV infection. A prospective study

Plasma glycoproteins are a composite biomarker of inflammation and can be detected byH-NMR. The aim of this study was to prospectively appraise the clinical value of plasma glycopro-teins assessed byH-NMR in people living with HIV (PLWH). A total of 221 patients with HIV infection were recruited and studied at baseline and at 48 and 144 weeks. Patients were distributed into two groups according to baseline CD4 T-cell number below or above 200 cells/µL. Patients with fewer than 200 cells/µL were distributed into the responders and nonresponders according to antiretroviral therapy (ART) response at 144 weeks. Glycoprotein concentrations were determined byH-NMR arising from the protein bond N-acetylglucosamine and N-acetylgalactosamine signals (GlycA); and N-acetylneuraminic acid signal (GlycB) associated with the sugar-protein bond con-centration and aggregation state (shapes (height/width)). Basal glycoprotein concentrations were higher in patients with < 200 CD4 T-cell/µL (Glyc A: 1040(917.9-1199.1) vs. 950.4(845.5-1050.9), p < 0.001, and Glyc B: 521(440.3-610.3) vs. 468.6(417.9-507.0) µ mol/L, p < 0.001) being reduced by ART. The height/width (H/W) ratio was the parameter showing a better association with this clinical sta-tus. Baseline glycoproteins predict the condition of responder/nonresponder. In this study,H-NMR glycoproteins provide novel insights to assess inflammation status and have prognostic value in PLWH

Effects of High Flavanol Dark Chocolate on Cardiovascular Function and Platelet Aggregation.

Regular consumption of chocolate and cocoa products has been linked to reduced cardiovascular mortality. This study compared the effects of high flavanol dark chocolate (HFDC; 1064mg flavanols/day for 6 weeks) and low flavanol dark chocolate (LFDC; 88mg flavanols/day for 6 weeks) on blood pressure, heart rate, vascular function and platelet aggregation in men with pre-hypertension or mild hypertension. Vascular function was assessed by pulse wave analysis using radial artery applanation tonometry in combination with inhaled salbutamol (0.4 mg) to assess changes due to endothelium-dependent vasodilatation. HFDC did not significantly reduce blood pressure compared to baseline or LFDC. Heart rate was increased by LFDC compared to baseline, but not by HFDC. Vascular responses to salbutamol tended to be greater after HFDC. Platelet aggregation induced by collagen or the thromboxane analogue U46619 was unchanged after LFDC or HFDC, whereas both chocolates reduced responses to ADP and the thrombin receptor activator peptide, SFLLRNamide (TRAP6), relative to baseline. Pre-incubation of platelets with theobromine also attenuated platelet aggregation induced by ADP or TRAP6. We conclude that consumption of HFDC confers modest improvements in cardiovascular function. Platelet aggregation is modulated by a flavanol-independent mechanism that is likely due to theobromine.This study was supported by a grant (to R. Corder) from Barry Callebaut Belgium N

Inertia and frequency support from Britain's AC powered trains

The penetration of converter connected generation is increasing globally, bringing with it valid concerns over the stability of the modern electricity network. In terms of frequency stability, the provision of inertia and frequency support from converter interfaced generation has been the topic of significant research with a wide range of systems considered. One resource that has avoided significant attention is the GB rail electrical rolling stock. Everyday thousands of trains run on a strict schedule, travelling at high speeds with considerable mass all acting as one large energy store. The AC connected trains possess regenerative braking systems allowing for this energy to be harvested. With simple software modifications this energy can be extracted during large frequency events. This article investigates the power available for inertia and frequency response throughout a working day. A sensitivity analysis of parameters is conducted and the work looks to the future by considering increasing penetration of AC trains. A response between 300 – 850 MW is estimated for a one-minute frequency response. The calculated energy and response profile was then used to investigate the effect that the trains would have had on the 9th of August power cut that occurred in the UK in 2019

Dipolar origin of the gas-liquid coexistence of the hard-core 1:1 electrolyte model

We present a systematic study of the effect of the ion pairing on the gas-liquid phase transition of hard-core 1:1 electrolyte models. We study a class of dipolar dimer models that depend on a parameter R_c, the maximum separation between the ions that compose the dimer. This parameter can vary from sigma_{+/-} that corresponds to the tightly tethered dipolar dimer model, to R_c --> infinity, that corresponds to the Stillinger-Lovett description of the free ion system. The coexistence curve and critical point parameters are obtained as a function of R_c by grand canonical Monte Carlo techniques. Our results show that this dependence is smooth but non-monotonic and converges asymptotically towards the free ion case for relatively small values of R_c. This fact allows us to describe the gas-liquid transition in the free ion model as a transition between two dimerized fluid phases. The role of the unpaired ions can be considered as a perturbation of this picture.Comment: 16 pages, 13 figures, submitted to Physical Review