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Purification and characterization of the intrinsically disordered Arabidopsis thaliana protein SOG1
No full textSOG1, a transcription factor consisting of a folded NAC (NAM-ATAF-CUC2) domain and an intrinsically disordered C-terminal domain (CTD), co-ordinates the DNA damage response in plants. Here we compare different methods to express and purify recombinant full length Arabidopsis thaliana SOG1. Expression in Sf9 insect cells results in a protein that contains a phosphorylated site that is possibly located on the T423 site in the CTD. This site is reported to be phosphorylated in planta upon aluminium toxicity stress and may affect the transcriptional activity of SOG1 in an yet undetermined way. Expression of SOG1 in E. coli BL21 (DE3) leads to the formation of inclusion bodies, a problem that is resolved by using a cleavable SUMO solubility tag. The resulting protein is not phosphorylated and represents the transcriptional inactive state of SOG1. Both protein preparations show similar CD spectra and melting temperatures. SEC-MALS determined that the proteins, like other NAC transcription factors, form a dimer in solution. Both proteins are also highly non-globular as determined by analytical SEC and are likely stretched out due to their disordered CTD. In electromobility shift assays, both insect and E. coli purified SOG1 proteins bind to a DNA fragment from the promoter region of SMR5, a well established target gene of SOG1, showing the functionality of both purified proteins.SOG1, a transcription factor consisting of a folded NAC (NAM-ATAF-CUC2) domain and an intrinsically disordered C-terminal domain (CTD), co-ordinates the DNA damage response in plants. Here we compare different methods to express and purify recombinant full length Arabidopsis thaliana SOG1. Expression in Sf9 insect cells results in a protein that contains a phosphorylated site that is possibly located on the T423 site in the CTD. This site is reported to be phosphorylated in planta upon aluminium toxicity stress and may affect the transcriptional activity of SOG1 in an yet undetermined way. Expression of SOG1 in E. coli BL21 (DE3) leads to the formation of inclusion bodies, a problem that is resolved by using a cleavable SUMO solubility tag. The resulting protein is not phosphorylated and represents the transcriptional inactive state of SOG1. Both protein preparations show similar CD spectra and melting temperatures. SEC-MALS determined that the proteins, like other NAC transcription factors, form a dimer in solution. Both proteins are also highly non-globular as determined by analytical SEC and are likely stretched out due to their disordered CTD. In electromobility shift assays, both insect and E. coli purified SOG1 proteins bind to a DNA fragment from the promoter region of SMR5, a well established target gene of SOG1, showing the functionality of both purified proteins.
Development of a bioavailability-based acute effects assessment method for nickel
No full textThis study aimed to develop a bioavailability-based effects assessment method for nickel (Ni) to derive acute freshwater environmental thresholds in Europe. The authors established a reliable acute freshwater Ni ecotoxicity database covering 63 different freshwater species, and the existing acute Ni bioavailability models for invertebrates were revised. A single average invertebrate bioavailability model was proposed, in which the protective effects of Ca2+ and Mg2+ on Ni2+ toxicity were integrated as a single-site competition effect at the Ni biotic ligand. The biotic ligand stability constants for Ca2+ and Mg2+ (log KCaBL = 3.80 and log KMgBL = 3.32) were derived by averaging these parameters from three existing cladoceran models. A pH extension was also integrated into the average invertebrate bioavailability model to reflect the increase in free Ni2+ toxicity observed greater than pH 8.0. The proposed invertebrate model has further been validated using an extensive dataset of acute toxicity data covering 15 different invertebrate species. Evaluating the extrapolation of the invertebrate model to plant species revealed significant uncertainty about the applicability of the acute Ni bioavailability models for plants. The newly developed acute invertebrate model was used alongside the existing acute fish and algae bioavailability models to support an acute bioavailability normalization approach for Ni. By combining these bioavailability models with the acute toxicity dataset for Ni, a normalized species sensitivity distribution approach is proposed to derive site-specific acute environmental thresholds, expressed by the HC5L(E)C50 (i.e., dissolved Ni concentration resulting in at least 50% effect for 5% of the species). The applicability ranges of the acute Ni bioavailability normalization approach are estimated to be valid for approximately 70% of European freshwaters. The proposed approach serves as a basis to incorporate bioavailability into the compliance evaluation relative to acute environmental threshold values for Ni in Europe.This study aimed to develop a bioavailability-based effects assessment method for nickel (Ni) to derive acute freshwater environmental thresholds in Europe. The authors established a reliable acute freshwater Ni ecotoxicity database covering 63 different freshwater species, and the existing acute Ni bioavailability models for invertebrates were revised. A single average invertebrate bioavailability model was proposed, in which the protective effects of Ca2+ and Mg2+ on Ni2+ toxicity were integrated as a single-site competition effect at the Ni biotic ligand. The biotic ligand stability constants for Ca2+ and Mg2+ (log KCaBL = 3.80 and log KMgBL = 3.32) were derived by averaging these parameters from three existing cladoceran models. A pH extension was also integrated into the average invertebrate bioavailability model to reflect the increase in free Ni2+ toxicity observed greater than pH 8.0. The proposed invertebrate model has further been validated using an extensive dataset of acute toxicity data covering 15 different invertebrate species. Evaluating the extrapolation of the invertebrate model to plant species revealed significant uncertainty about the applicability of the acute Ni bioavailability models for plants. The newly developed acute invertebrate model was used alongside the existing acute fish and algae bioavailability models to support an acute bioavailability normalization approach for Ni. By combining these bioavailability models with the acute toxicity dataset for Ni, a normalized species sensitivity distribution approach is proposed to derive site-specific acute environmental thresholds, expressed by the HC5L(E)C50 (i.e., dissolved Ni concentration resulting in at least 50% effect for 5% of the species). The applicability ranges of the acute Ni bioavailability normalization approach are estimated to be valid for approximately 70% of European freshwaters. The proposed approach serves as a basis to incorporate bioavailability into the compliance evaluation relative to acute environmental threshold values for Ni in Europe.A
The relationships among workload, automation reliance, and human errors in safety-critical monitoring roles
No full textWhile advanced automation technology has alleviated human workload and gradually transformed traditional manual work to monitoring, accidents due to human errors remain one of the largest contributors to unsafe operations. To inform improved managerial decisions, this paper studies how reliance on automation, under different amounts of workload, affects the number of errors in safety-critical socio-technical systems. Using a unique real-world dataset from Railway Traffic Control Centers, that contain 410,269 controller-hour observations, we employ count model analysis to investigate the relationship between human errors with workload and automation usage. Our findings reveal that traffic controller performance (represented by human errors) has a positive relationship with workload, and an inverted U-shape relationship with automation usage. Moreover, there is a significant interaction between the level of workload and automation usage. These insights offers a nuanced understanding of how cognitive workload and automation reliance impact worker performance. Our results suggest that people make fewer mistakes when doing all of (or most of) the work manually or when monitoring the automated system that is doing all or most of the work automatically. These findings provide actionable recommendations for managers on optimizing workload and automation usage balance for safetycritical enviroments.While advanced automation technology has alleviated human workload and gradually transformed traditional manual work to monitoring, accidents due to human errors remain one of the largest contributors to unsafe operations. To inform improved managerial decisions, this paper studies how reliance on automation, under different amounts of workload, affects the number of errors in safety-critical socio-technical systems. Using a unique real-world dataset from Railway Traffic Control Centers, that contain 410,269 controller-hour observations, we employ count model analysis to investigate the relationship between human errors with workload and automation usage. Our findings reveal that traffic controller performance (represented by human errors) has a positive relationship with workload, and an inverted U-shape relationship with automation usage. Moreover, there is a significant interaction between the level of workload and automation usage. These insights offers a nuanced understanding of how cognitive workload and automation reliance impact worker performance. Our results suggest that people make fewer mistakes when doing all of (or most of) the work manually or when monitoring the automated system that is doing all or most of the work automatically. These findings provide actionable recommendations for managers on optimizing workload and automation usage balance for safetycritical enviroments.A
Institutions and the real effects of private equity buyouts : a meta‐analysis
No full textResearch Summary This study reviews four decades of fragmented and contradictory empirical literature on the real effects of private equity (PE) buyouts on portfolio companies, differentiating between efficiency and growth outcomes. We hypothesize how institutional forces, including regulatory, cognitive, and normative institutions explain heterogeneity in post-buyout efficiency and growth across time and countries. We argue that competition and population-level learning have shifted the cognitive frame underlying value creation in buyouts from financial engineering toward operational engineering and strategic entrepreneurship. Using meta-analysis, we find support for several of our hypotheses using samples from 66 empirical studies across the finance, management, economics, and entrepreneurship disciplines.Managerial SummaryThis study delves into four decades of fragmented private equity (PE) literature to unravel the practical implications for post-buyout efficiency and growth. Using meta-analysis, we explore the role of institutional forces-regulatory, cognitive, and normative-in shaping outcomes across diverse temporal and geographical contexts. We observe an overall paradigm shift in PE value creation over time, transitioning from focusing on financial engineering to operational value creation and strategic entrepreneurship. This transformation is driven by heightened competition and widespread population-level learning. Validating our hypotheses through a thorough examination of 66 empirical studies spanning finance, management, economics, and entrepreneurship disciplines, our findings offer insights for policymakers and practitioners navigating the nuanced landscape of PE buyouts.Research Summary This study reviews four decades of fragmented and contradictory empirical literature on the real effects of private equity (PE) buyouts on portfolio companies, differentiating between efficiency and growth outcomes. We hypothesize how institutional forces, including regulatory, cognitive, and normative institutions explain heterogeneity in post-buyout efficiency and growth across time and countries. We argue that competition and population-level learning have shifted the cognitive frame underlying value creation in buyouts from financial engineering toward operational engineering and strategic entrepreneurship. Using meta-analysis, we find support for several of our hypotheses using samples from 66 empirical studies across the finance, management, economics, and entrepreneurship disciplines.Managerial SummaryThis study delves into four decades of fragmented private equity (PE) literature to unravel the practical implications for post-buyout efficiency and growth. Using meta-analysis, we explore the role of institutional forces-regulatory, cognitive, and normative-in shaping outcomes across diverse temporal and geographical contexts. We observe an overall paradigm shift in PE value creation over time, transitioning from focusing on financial engineering to operational value creation and strategic entrepreneurship. This transformation is driven by heightened competition and widespread population-level learning. Validating our hypotheses through a thorough examination of 66 empirical studies spanning finance, management, economics, and entrepreneurship disciplines, our findings offer insights for policymakers and practitioners navigating the nuanced landscape of PE buyouts.A
Гент и културните войни: какво е бъдещето на демокрацията в Европа?
No full textIn today’s editorial, Le Monde notes that the question of Trump as a threat to democracy is becoming increasingly urgent. After U.S. Vice President J.D. Vance’s speech in Munich on February 14, there is no longer any room for doubt – Washington is becoming an adversary of Europe not only economically and geostrategically, but also politically and ideologically. The refusal to support Ukraine, criticism of NATO, and the surprising defense of Vladimir Putin against Volodymyr Zelensky outline a new line of confrontation between the U.S. and European democracies.At the same time, in the cultural and media sphere, a new axis of opposition is crystallizing: tech billionaires versus public figures defending liberal values. “It seems like every day we hear about yet another inexplicable, chaotic move that seems aimed at undermining everything we, as Americans, hold dear,” said Stephen Colbert, host of The Late Show. Colbert criticized Musk, saying his actions appear increasingly incompetent and chaotic. This is not merely a personal antagonism but a symbol of a global battle between technocratic governance and the democratic ideal of a society founded on social justice and ethical leadership. If this trend continues, will democracy in Europe be able to withstand the rising wave of authoritarianism and populism?In today’s editorial, Le Monde notes that the question of Trump as a threat to democracy is becoming increasingly urgent. After U.S. Vice President J.D. Vance’s speech in Munich on February 14, there is no longer any room for doubt – Washington is becoming an adversary of Europe not only economically and geostrategically, but also politically and ideologically. The refusal to support Ukraine, criticism of NATO, and the surprising defense of Vladimir Putin against Volodymyr Zelensky outline a new line of confrontation between the U.S. and European democracies.At the same time, in the cultural and media sphere, a new axis of opposition is crystallizing: tech billionaires versus public figures defending liberal values. “It seems like every day we hear about yet another inexplicable, chaotic move that seems aimed at undermining everything we, as Americans, hold dear,” said Stephen Colbert, host of The Late Show. Colbert criticized Musk, saying his actions appear increasingly incompetent and chaotic. This is not merely a personal antagonism but a symbol of a global battle between technocratic governance and the democratic ideal of a society founded on social justice and ethical leadership. If this trend continues, will democracy in Europe be able to withstand the rising wave of authoritarianism and populism?
Factors associated with statural growth in pediatric kidney transplant recipients with focus on metabolic acidosis
No full textBackground : We investigated factors associated with post-transplant growth in pediatric kidney transplant (KTx) recipients with a focus on plasma bicarbonate (HCO3−) and estimated the effect of alkali treatment on growth. Methods :In this study of the CERTAIN Registry, data were collected up to 5 years post-transplant. Generalized Additive Mixed Models were applied to assess the association between post-transplant growth and covariates. A trial-emulation analysis was performed to estimate the causal effect of alkali supplementation on growth. Results : We report on 2147 primary KTx recipients with a median age at KTx of 10.2 (IQR 5.1;14.3) years. No statistically significant association was found between growth and HCO3− (p = 0.21), but the shape of the estimated conditional association showed a decreasing estimated growth with increasing HCO3−. Glucocorticoid treatment and allograft rejection showed an inverse association with growth. Living donor KTx, glomerulopathy, recombinant growth hormone use, low height z-score at KTx, younger age, and higher eGFR were positively associated with growth. The trial-emulation analysis included patients at 30 days and 3, 6, and 9 months post-transplant with HCO3− < 22 mmol/L and no prior alkaline treatment. Alkaline treatment was initiated in 194, 93, 47, and 25 patients, respectively. After adjustment for confounders, there was no significant difference in growth at 1-year post-transplant in treated and untreated patients. Conclusions : We found no association between HCO3− and growth nor evidence of improved growth after treatment of metabolic acidosis. Living donor KTx was positively associated with post-transplant growth, while there was an inverse association with allograft rejection.Background : We investigated factors associated with post-transplant growth in pediatric kidney transplant (KTx) recipients with a focus on plasma bicarbonate (HCO3−) and estimated the effect of alkali treatment on growth. Methods :In this study of the CERTAIN Registry, data were collected up to 5 years post-transplant. Generalized Additive Mixed Models were applied to assess the association between post-transplant growth and covariates. A trial-emulation analysis was performed to estimate the causal effect of alkali supplementation on growth. Results : We report on 2147 primary KTx recipients with a median age at KTx of 10.2 (IQR 5.1;14.3) years. No statistically significant association was found between growth and HCO3− (p = 0.21), but the shape of the estimated conditional association showed a decreasing estimated growth with increasing HCO3−. Glucocorticoid treatment and allograft rejection showed an inverse association with growth. Living donor KTx, glomerulopathy, recombinant growth hormone use, low height z-score at KTx, younger age, and higher eGFR were positively associated with growth. The trial-emulation analysis included patients at 30 days and 3, 6, and 9 months post-transplant with HCO3− < 22 mmol/L and no prior alkaline treatment. Alkaline treatment was initiated in 194, 93, 47, and 25 patients, respectively. After adjustment for confounders, there was no significant difference in growth at 1-year post-transplant in treated and untreated patients. Conclusions : We found no association between HCO3− and growth nor evidence of improved growth after treatment of metabolic acidosis. Living donor KTx was positively associated with post-transplant growth, while there was an inverse association with allograft rejection.A
Tongue and lip strength and endurance in healthy young adults with and without orofacial myofunctional disorders
No full textBackground/Objectives : Based on the premise that tongue and lip force is affected in individuals with orofacial myofunctional disorders (OMDs), orofacial myofunctional therapy (OMT) programs typically include the strengthening of orofacial muscles through isometric and isotonic exercises. The purpose of this study is to examine whether there is indeed a measurable difference in maximum tongue and lip strength and endurance between subjects with and without OMDs, as well as to explore Oral Health-Related Quality of Life (OHRQoL) in this population. Methods : Sixty healthy young adults (mean age 18.9 years, SD 0.69 years, range 18.0–21.4 years) participated in this study. Perceptual evaluation of orofacial functions was conducted using the Orofacial Myofunctional Evaluation with Scores (OMES) protocol. Participants were divided into three groups, namely those with physiological orofacial functions (POF; n = 20), those with inconsistent orofacial functions (IOF; n = 11), and those with consistent OMDs (OMD; n = 29). Maximum isometric pressure and endurance of tongue and lips were measured using the Iowa Oral Performance Instrument (IOPI). OHRQoL was assessed using the Oral Health Impact Profile (OHIP-14). Results : The OMES total scores did not differ significantly between the three groups, though the subscale ‘function’ showed significant differences (13.637; p = 0.001). No statistically significant differences in maximum isometric pressure or endurance for tongue and lips, nor for OHIP scores, were measured between the three groups. Conclusions : Although orofacial muscle strengthening is commonly part of OMT, current findings suggest the superfluity of these types of exercises in the treatment of OMDs in healthy young adults and may indicate the need to focus on awareness and rehabilitation of pathological functions in these individuals. Re-evaluation of the efficacy of OMT programs in different populations may be an important strategy going forward.Background/Objectives : Based on the premise that tongue and lip force is affected in individuals with orofacial myofunctional disorders (OMDs), orofacial myofunctional therapy (OMT) programs typically include the strengthening of orofacial muscles through isometric and isotonic exercises. The purpose of this study is to examine whether there is indeed a measurable difference in maximum tongue and lip strength and endurance between subjects with and without OMDs, as well as to explore Oral Health-Related Quality of Life (OHRQoL) in this population. Methods : Sixty healthy young adults (mean age 18.9 years, SD 0.69 years, range 18.0–21.4 years) participated in this study. Perceptual evaluation of orofacial functions was conducted using the Orofacial Myofunctional Evaluation with Scores (OMES) protocol. Participants were divided into three groups, namely those with physiological orofacial functions (POF; n = 20), those with inconsistent orofacial functions (IOF; n = 11), and those with consistent OMDs (OMD; n = 29). Maximum isometric pressure and endurance of tongue and lips were measured using the Iowa Oral Performance Instrument (IOPI). OHRQoL was assessed using the Oral Health Impact Profile (OHIP-14). Results : The OMES total scores did not differ significantly between the three groups, though the subscale ‘function’ showed significant differences (13.637; p = 0.001). No statistically significant differences in maximum isometric pressure or endurance for tongue and lips, nor for OHIP scores, were measured between the three groups. Conclusions : Although orofacial muscle strengthening is commonly part of OMT, current findings suggest the superfluity of these types of exercises in the treatment of OMDs in healthy young adults and may indicate the need to focus on awareness and rehabilitation of pathological functions in these individuals. Re-evaluation of the efficacy of OMT programs in different populations may be an important strategy going forward.A
Layer interface characteristics and adhesion of 3D printed cement-based materials exposed to post-printing temperature disturbance
No full textThe layer interface, which is vital for the performance and longevity of 3D printed cement-based materials (3DPCM), is very sensitive to the environmental conditions because of the lack of formwork. Nevertheless, the current limited understanding of how temperature affects the layer interface has restricted the application of 3D printing in different construction scenarios. Here, we revealed the effects of temperature on the multi-scale phase distribution features of the layer interface through mercury intrusion porosimetry, X-ray computed tomography, nanoindentation and scanning electron microscopy with energy dispersive spectroscopy techniques. Additionally, the interlayer bond strength of 3DPCM was evaluated via the splitting tensile test. Small amplitude oscillation, surface roughness and isothermal calorimetry measurements were employed for an in-depth analysis the mechanisms. Results indicate that an increase in temperature post-printing reduces the discrepancies aggregate volume fraction between the layer interface and bulk matrix due to the increasing structuration rate and the amount of cement paste at the interface due to the reduced settlement of aggregates. The porosity difference between the layer interface and bulk matrix decreased with increasing temperature due to the pore size refinement by faster filling with hydrates. In addition, a more concentrated distribution of atomic ratios and elastic modulus of hydrates were observed at the layer interface of 3DPCM hardened at higher temperatures. Increased curing temperature improves the interlayer bond strength of 3DPCM owing to the enhanced aggregate interlocking, reduced porosity and improved high-density CSH content.The layer interface, which is vital for the performance and longevity of 3D printed cement-based materials (3DPCM), is very sensitive to the environmental conditions because of the lack of formwork. Nevertheless, the current limited understanding of how temperature affects the layer interface has restricted the application of 3D printing in different construction scenarios. Here, we revealed the effects of temperature on the multi-scale phase distribution features of the layer interface through mercury intrusion porosimetry, X-ray computed tomography, nanoindentation and scanning electron microscopy with energy dispersive spectroscopy techniques. Additionally, the interlayer bond strength of 3DPCM was evaluated via the splitting tensile test. Small amplitude oscillation, surface roughness and isothermal calorimetry measurements were employed for an in-depth analysis the mechanisms. Results indicate that an increase in temperature post-printing reduces the discrepancies aggregate volume fraction between the layer interface and bulk matrix due to the increasing structuration rate and the amount of cement paste at the interface due to the reduced settlement of aggregates. The porosity difference between the layer interface and bulk matrix decreased with increasing temperature due to the pore size refinement by faster filling with hydrates. In addition, a more concentrated distribution of atomic ratios and elastic modulus of hydrates were observed at the layer interface of 3DPCM hardened at higher temperatures. Increased curing temperature improves the interlayer bond strength of 3DPCM owing to the enhanced aggregate interlocking, reduced porosity and improved high-density CSH content.A