Storage and transportation of hydrogen is a major obstacle for its use as a fuel. An increasingly considered alternative for the direct handling of hydrogen is to use carbon dioxide (CO₂) as an ...intermediate storage material. However, CO₂ is thermodynamically stable, and developed chemical catalysts often require high temperatures, pressures, and/or additives for high catalytic rates. Here, we present the discovery of a bacterial hydrogen-dependent carbon dioxide reductase from Acetobacterium woodii directly catalyzing the hydrogenation of CO₂. We also demonstrate a whole-cell system able to produce formate as the sole end product from dihydrogen (H₂) and CO₂ as well as syngas. This discovery opens biotechnological alternatives for efficient CO₂ hydrogenation either by using the isolated enzyme or by employing whole-cell catalysis.
ABSTRACT
It is generally agreed that models that better simulate historical and current features of climate should also be the ones that more reliably simulate future climate. This article describes ...the ability of a selection of global climate models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) to represent the historical and current mean climate and its variability over northeastern Argentina, a region that exhibits frequent extreme events. Two types of simulations are considered: Long‐term simulations for 1901–2005 in which the models respond to climate forcing (e.g. changes in atmospheric composition and land use) and decadal simulations for 1961–2010 that are initialized from observed climate states. Monthly simulations of precipitation and temperature are statistically evaluated for individual models and their ensembles.
Subsets of models that best represent the region's climate are further examined. First, models that have a Nash–Sutcliffe efficiency of at least 0.8 are taken as a subset that best represents the observed temperature fields and the mean annual cycle. Their temperature time series are in phase with observations (r > 0.92), despite systematic errors that if desired can be corrected by statistical methods. Likewise, models that have a precipitation Pearson correlation coefficient of at least 0.6 are considered that best represent regional precipitation features. GCMs are able to reproduce the annual precipitation cycle, although they underestimate precipitation amounts during the austral warm season (September through April) and slightly overestimate the cold season rainfall amounts. The ensembles for the subsets of models achieve the best evaluation metrics, exceeding the performance of the overall ensembles as well as those of the individual models.
The northeast region of Argentina present hydro‐climatic variability at various time scales and undergoes changes in extreme events that could be exacerbated in the coming decades. Reliable projections of future climate require models that adequately represent the regional climate system. This paper evaluates the ability of 27 global climate models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) to simulate the observed climate and selects a subset of 9 models for temperature and 7 models for precipitation. The multi‐model ensembles using selected GCMs improve the performance of each individual GCM.
This study examines the joint variability of precipitation, river streamflow and temperature over northeastern Argentina; advances the understanding of their links with global SST forcing; and ...discusses their impacts on water resources, agriculture and human settlements. The leading patterns of variability, and their nonlinear trends and cycles are identified by means of a principal component analysis (PCA) complemented with a singular spectrum analysis (SSA). Interannual hydroclimatic variability centers on two broad frequency bands: one of 2.5–6.5 years corresponding to El Niño Southern Oscillation (ENSO) periodicities and the second of about 9 years. The higher frequencies of the precipitation variability (2.5–4 years) favored extreme events after 2000, even during moderate extreme phases of the ENSO. Minimum temperature is correlated with ENSO with a main frequency close to 3 years. Maximum temperature time series correlate well with SST variability over the South Atlantic, Indian and Pacific oceans with a 9-year frequency. Interdecadal variability is characterized by low-frequency trends and multidecadal oscillations that have induced a transition from dryer and cooler climate to wetter and warmer decades starting in the mid-twentieth century. The Paraná River streamflow is influenced by North and South Atlantic SSTs with bidecadal periodicities. The hydroclimate variability at all timescales had significant sectoral impacts. Frequent wet events between 1970 and 2005 favored floods that affected agricultural and livestock productivity and forced population displacements. On the other hand, agricultural droughts resulted in soil moisture deficits that affected crops at critical growth stages. Hydrological droughts affected surface water resources, causing water and food scarcity and stressing the capacity for hydropower generation. Lastly, increases in minimum temperature reduced wheat and barley yields.
Abstract This work examines the characteristics and prevalent life cycle of agricultural flash droughts globally. Using ERA5 data, the study introduces a flash drought indicator based on soil water ...availability. This approach integrates root-zone soil moisture and hydraulic soil properties, such as field capacity and wilting point, to couple the rapid soil moisture depletion and plant water stress. Our findings reveal that agricultural flash droughts present their higher frequency predominantly during the critical growth periods of crops. Notably, these droughts exhibit a similar life cycle regardless of the location or climatic regime. The primary cause of the rapid soil moisture depletion is the precipitation deficit, but evapotranspiration also plays a significant role. In an energy-limited environment, evapotranspiration rapidly increases before the onset and decreases rapidly during the intensification period as the system becomes water-limited. Upon concluding the intensification period, most crops experience water stress, diminishing their yields.
Neuroimaging evidence suggests that executive functions (EF) depend on brain regions that are not closely tied to specific cognitive demands but rather to a wide range of behaviors. A multiple-demand ...(MD) system has been proposed, consisting of regions showing conjoint activation across multiple demands. Additionally, a number of studies defining networks specific to certain cognitive tasks suggest that the MD system may be composed of a number of sub-networks each subserving specific roles within the system. We here provide a robust definition of an extended MDN (eMDN) based on task-dependent and task-independent functional connectivity analyses seeded from regions previously shown to be convergently recruited across neuroimaging studies probing working memory, attention and inhibition, i.e., the proposed key components of EF. Additionally, we investigated potential sub-networks within the eMDN based on their connectional and functional similarities. We propose an eMDN network consisting of a core whose integrity should be crucial to performance of most operations that are considered higher cognitive or EF. This then recruits additional areas depending on specific demands.
•A neurobiological substrate for executive processes is proposed.•Proposed network consists of a core, crucial to performance of executive functions.•Core network in turn recruits other brain regions depending on specific demands.•Hierarchical clustering grouped regions into three cliques each with specific roles.
Circulating tumor cells (CTCs) were introduced as biomarkers more than 10 years ago, but capture of viable CTCs at high purity from peripheral blood of cancer patients is still a major technical ...challenge. Here, we report a novel microfluidic platform designed for marker independent capture of CTCs. The Parsortix™ cell separation system provides size and deformability‐based enrichment with automated staining for cell identification, and subsequent recovery (harvesting) of cells from the device. Using the Parsortix™ system, average cell capture inside the device ranged between 42% and 70%. Subsequent harvest of cells from the device ranged between 54% and 69% of cells captured. Most importantly, 99% of the isolated tumor cells were viable after processing in spiking experiments as well as after harvesting from patient samples and still functional for downstream molecular analysis as demonstrated by mRNA characterization and array‐based comparative genomic hybridization. Analyzing clinical blood samples from metastatic (n = 20) and nonmetastatic (n = 6) cancer patients in parallel with CellSearch® system, we found that there was no statistically significant difference between the quantitative behavior of the two systems in this set of twenty six paired separations. In conclusion, the epitope independent Parsortix™ system enables the isolation of viable CTCs at a very high purity. Using this system, viable tumor cells are easily accessible and ready for molecular and functional analysis. The system's ability for enumeration and molecular characterization of EpCAM‐negative CTCs will help to broaden research into the mechanisms of cancer as well as facilitating the use of CTCs as “liquid biopsies.”
What's new?
Circulating tumor cells (CTCs) carry vital information about a tumor but are few in number, challenging their use as diagnostic tools. Moreover, not all CTCs express epithelial markers, holding back the advance of promising approaches based on the combination of cell‐surface antigen targeting with microfluidic technology. Here, an antigen‐independent microfluidic separation platform based on differences in cell size and deformability is shown to effectively capture CTCs, enabling the isolation of CTCs from tumors lacking epithelial markers. The capture of viable CTCs from peripheral blood paves the way to the future use of “liquid biopsies” in cancer diagnosis.
This study evaluates the ability of 19 models of CMIP phase 6 (CMIP6) to simulate Paraguay’s climate features. Historical multi-member simulations of single models and their multi-model ensembles are ...bias-corrected and evaluated with statistical metrics. Future projections of precipitation and temperature are generated with the ensembles for three integrated scenarios of socio-economic development and greenhouse gas emissions (SSP1–2.6, SSP2–4.5, and SSP5–8.5).
The 19 models simulate well the observed mean temperature. The bias-corrected multi-model ensemble reaches the highest skill scores and accurately reproduces the mean spatial field and annual cycle. The bias-corrected multi-model ensemble of precipitation represents the annual cycle weakly, missing the sharp onset and decay of the South American Monsoon. Some individual models and the multi-model ensemble correctly reproduce the west-east gradient, although they underestimate its pronounced spatial variability.
Ensembles of future simulations project that by 2100, the annual mean temperature will increase for the three scenarios. On average, the increases are almost 1.7 °C in the sustainable development and low emissions scenario (SSP1–2.6), 3 °C in the middle-of-the-road development and medium emissions scenario (SSP2–4.5), and 5.5 °C in the fossil-fueled development and high emissions scenario (SSP5–8.5). Models project a slight decrease in annual precipitation towards the northwest (less than 50 mm) and an increase towards the southeast (more than 200 mm). Paraguay’s humid eastern part is projected to have a small growth in temperature and an increase in precipitation. In contrast, the western arid Chaco region would experience a substantial increase in temperature, while rainfall would slightly decrease.
Introduction
Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and/or impulsivity. It is one of the most common ...disabilities in college populations and comorbidity with depression is frequently reported.
Objectives
The aim of the study is to shed light on depression as comorbidity and other intrapersonal correlates of ADHD in young adults.
Methods
Participants were Hungarian university students (N=420; M=24.5, SD=5.0 years). Criteria of the ADHD group were based on the Adult ADHD Self Report Scale V1.1 (ASRS-V.1.1) screening tool. The participants filled in the Beck’s Depression Inventory, the Hyperfocus Scale, Flow State Scale, Academic Persistence Scale, Satisfaction With Life Scale, General Self-Efficacy Scale, and the Connor-Davidson Resilience Scale.
Results
We found that in the group of students who had ADHD symptoms, depression score was significantly (p<.001) higher (M=18.38, SD=5.87) than the control group’s scores (M=14.56, SD=4.45). Frequency of severe depression was 13.4% (moderate: 33.5%) while in the control group: 1.6% and 17.6% respectively. Participants reporting ADHD symptoms (N=164, 39%) also reported lower levels of resilience (M=23.40, SD=6.96), relative to their non-ADHD peers (M=27.69, SD=6.48). Significant differences were found in the areas of self-efficacy, depression, flow and hyperfocus as well, and ADHD symptoms contributed to lower level of life satisfaction (β=-0.24, p<.001).
Conclusions
Our findings suggest that university students reporting symptoms of ADHD may be assisted with strategies that are focused on increasing protective factors (i.e., resilience, self-efficacy, flow) to prevent depression and improve their life satisfaction and quality of life.
Disclosure
No significant relationships.
An isoelectronic and isostructural series of cyclometalated azido complexes M(N3)(dpb) with M = Ni(II), Pd(II), Pt(II), and Au(III) based on the N^C^N pincer ligand 1,3-di(2-pyridyl)phenide ...(dpb) was characterized by X-ray diffraction analysis and investigated for reactivity in the iClick reaction with a wide range of internal and terminal alkynes by using 1H and 19F NMR spectroscopy. Reaction rate constants were found to increase with greater charge density in the order Ni(II) > Pd(II) > Pt(II) > Au(III). Terminal alkynes R–CC–R′ with strongly electron-withdrawing groups R and R′ exhibited faster kinetics than those with electron-donating substituents in the order CF3 > ketone > ester > H > phenyl ≫ amide, while R = CH3 resulted in complete loss of reactivity. Four symmetrical triazolato complexes M(triazolatoCOOCH3,COOCH3)(dpb) with M = Ni(II), Pd(II), Pt(II), and Au(III) as well as four nonsymmetrically substituted triazolato complexes Pt(triazolatoR,R′ )(dpb) originating from terminal and internal alkynes were shown by X-ray crystal structure analysis to exclusively feature N2-coordination of the five-membered ring ligand. However, the Pt(II) triazolato complexes exist as a mixture of N1- and N2-coordinated species in solution. Torsion angles between the mean planes of the N^C^N pincer and the triazolato ligand increase from a nearly coplanar to a perpendicular arrangement when going from Au(III)/Pt(II)/Pd(II) to Ni(II), while different substituents R and R′ on the alkyne have no influence on the torsion angle and were rationalized by DFT calculations. Finally, a carbohydrate derivative obtained by glucuronic acid conjugation to methyl propiolate demonstrates the facile biofunctionalization of metal complexes via the iClick reaction.
There is high confidence that global warming intensifies all components of the global water cycle. This work investigates the possible effects of global warming on river flows worldwide in the coming ...decades. We conducted 18 global hydrological simulations to assess how river flows are projected to change in the near future (2015–2050) compared to the recent past (1950–2014). The simulations are forced by runoff from the High Resolution Model Intercomparison Project (HighResMIP) CMIP6 global climate models (GCMs), which assume a high-emission scenario for the projections. The assessment includes estimating the signal-to-noise (S/N) ratio and the time of emergence (ToE) of all the rivers in the world. Consistently with the water cycle intensification, the hydrological simulations project a clear positive global river discharge trend from ∼2000 that emerges beyond the levels of natural variability and becomes “unfamiliar” by 2017 and “unusual” by 2033. Simulations agree that the climate change signal is dominated by strong increases in the flows of rivers originating in central Africa and South Asia and those discharging into the Arctic Ocean, partially compensated for by the reduced flow projected for Patagonian rivers. The potential implications of such changes may include more frequent floods in central African and South Asian rivers, driven by the projected magnification of the annual cycles with unprecedented peaks, a freshening of the Arctic Ocean from extra freshwater release, and limited water availability in Patagonia given the projected drier conditions of its rivers. This underscores the critical need for a paradigm shift in prioritizing water-related concerns amidst the challenges of global warming.
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