Artificial selection is a promising approach to manipulate microbial communities. Here, we report the outcome of two artificial selection experiments at the microbial community level. Both used ...“propagule” selection strategies, whereby the best-performing communities are used as the inocula to form a new generation of communities. Both experiments were contrasted to a random selection control. The first experiment used a defined set of strains as the starting inoculum, and the function under selection was the amylolytic activity of the consortia. The second experiment used multiple soil communities as the starting inocula, and the function under selection was the communities’ cross-feeding potential. In both experiments, the selected communities reached a higher mean function than the control. In the first experiment, this was caused by a decline in function of the control, rather than an improvement of the selected line. In the second experiment, this response was fueled by the large initial variance in function across communities, and stopped when the top-performing community “fixed” in the metacommunity. Our results are in agreement with basic expectations from breeding theory, pointing to some of the limitations of community-level selection experiments that can inform the design of future studies.
Insight into COVID-19 intensive care unit (ICU) patient characteristics, rates and risks of invasive mechanical ventilation (IMV) and associated outcomes as well as any regional discrepancies is ...critical in this pandemic for individual case management and overall resource planning.
Electronic searches were performed for reports through May 1 2020 and reports on COVID-19 ICU admissions and outcomes were included using predefined search terms. Relevant data was subsequently extracted and pooled using fixed or random effects meta-analysis depending on heterogeneity. Study quality was assessed by the NIH tool and heterogeneity was assessed by I2 and Q tests. Baseline patient characteristics, ICU and IMV outcomes were pooled and meta-analyzed. Pooled odds ratios (pOR) were calculated for clinical features against ICU, IMV mortality. Subgroup analysis was carried out based on patient regions. A total of twenty-eight studies comprising 12,437 COVID-19 ICU admissions from seven countries were meta-analyzed. Pooled ICU admission rate was 21% 95% CI 0.12-0.34 and 69% of cases needed IMV 95% CI 0.61-0.75. ICU and IMV mortality were 28.3% 95% CI 0.25-0.32, 43% 95% CI 0.29-0.58 and ICU, IMV duration was 7.78 95% CI 6.99-8.63 and 10.12 95% CI 7.08-13.16 days respectively. Besides confirming the significance of comorbidities and clinical findings of COVID-19 previously reported, we found the major correlates with ICU mortality were IMV pOR 16.46, 95% CI 4.37-61.96, acute kidney injury (AKI) pOR 12.47, 95% CI 1.52-102.7, and acute respiratory distress syndrome (ARDS) pOR 6.52, 95% CI 2.66-16.01. Subgroup analyses confirm significant regional discrepancies in outcomes.
This is a comprehensive systematic review and meta-analysis of COVID-19 ICU and IMV cases and associated outcomes. The significant association of AKI, ARDS and IMV with mortality has implications for ICU resource planning for AKI and ARDS as well as suggesting the need for further research into optimal ventilation strategies for COVID-19 patients in the ICU setting. Regional differences in outcome implies a need to develop region specific protocols for ventilatory support as well as overall treatment.
Context
The flipped classroom (FC), reversing lecture and homework elements of a course, is popular in medical education. The FC uses technology‐enhanced pre‐class learning to transmit knowledge, ...incorporating in‐class interaction to enhance higher cognitive learning. However, the FC model is expensive and research on its effectiveness remains inconclusive. The aim of this study was to compare the efficacy of the FC model over traditional lecture‐based (LB) learning by meta‐analysis.
Methods
We systematically searched MEDLINE, PubMed, ERIC, CINAHL, EMBASE, reference lists and Association for Medical Education in Europe (AMEE) conference books. Controlled trials comparing academic outcomes between the FC and LB approaches in higher education were considered eligible. The main findings were pooled using a random‐effects model when appropriate.
Results
Forty‐six studies (9026 participants) were included, comprising four randomised controlled trials (RCTs), 19 quasi‐experimental studies and 23 cohort studies. Study populations were health science (n = 32) and non health science (n = 14) students. The risk of bias was high (36/37 articles). Meta‐analyses revealed that the FC had significantly better outcomes than the LB method in examination scores (post‐intervention and pre–post change) and course grades, but not in objective structured clinical examination scores. Subgroup analyses showed the advantage of the FC was not observed in RCTs, non‐USA countries, nursing and other health science disciplines and earlier publication years (2013 and 2014). Cumulative analysis and meta‐regression suggested a tendency for progressively better outcomes by year. Outcome assessments rarely focused on behaviour change.
Conclusions
The FC method is associated with greater academic achievement than the LB approach for higher‐level learning outcomes, which has become more obvious in recent years. However, results should be interpreted with caution because of the high methodological diversity, statistical heterogeneity and risk of bias in the studies used. Future studies should have high methodological rigour, a standardised FC format and utilise assessment tools evaluating higher cognitive learning and behaviour change to further examine differences between FC and LB learning.
The authors’ meta‐analysis (46 studies, >9000 participants, health and non‐health science education) found flipped classrooms generally have significantly better learning outcomes than lecture learning, with a tendency for better outcomes for more recent studies.
Chemical modification of electrode materials by heteroatom dopants is crucial for improving storage performance in rechargeable batteries. Electron configurations of different dopants significantly ...influence the chemical interactions inbetween and the chemical bonding with the host material, yet the underlying mechanism remains unclear. We revealed competitive doping chemistry of Group IIIA elements (boron and aluminum) taking nickel‐rich cathode materials as a model. A notable difference between the atomic radii of B and Al accounts for different spatial configurations of the hybridized orbital in bonding with lattice oxygen. Density functional theory calculations reveal, Al is preferentially bonded to oxygen and vice versa, and shows a much lower diffusion barrier than BIII. In the case of Al‐preoccupation, the bulk diffusion of BIII is hindered. In this way, a B‐rich surface and Al‐rich bulk is formed, which helps to synergistically stabilize the structural evolution and surface chemistry of the cathode.
A model study has been performed on Group IIIA element (boron and aluminum) co‐doped high‐nickel layered oxide cathode materials to understand competitive doping chemistry. A notable difference between the atomic radii of B and Al accounts for different spatial configurations of the hybridized orbital in bonding with lattice oxygen, resulting in the formation of a B‐rich surface and an Al‐rich bulk.
Abstract
Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an
l
...-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS
2
(SnS
2
-C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO
2
to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS
2
lattice, resulting in different photophysical properties as compared with undoped SnS
2
. This SnS
2
-C photocatalyst significantly enhances the CO
2
reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS
2
-C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO
2
reduction under visible light, where the in situ carbon-doped SnS
2
nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.
Understanding the mechanisms that maintain microbial biodiversity is a critical aspiration in ecology. Past work on microbial coexistence has largely focused on species pairs, but it is unclear ...whether pairwise coexistence in isolation is required for coexistence in a multispecies community. To address this question, we conducted hundreds of pairwise competition experiments among the stably coexisting members of 12 different enrichment communities in vitro. To determine the outcomes of these experiments, we developed an automated image analysis pipeline to quantify species abundances. We found that competitive exclusion was the most common outcome, and it was strongly hierarchical and transitive. Because many species that coexist within a stable multispecies community fail to coexist in pairwise co-culture under identical conditions, we concluded that multispecies coexistence is an emergent phenomenon. This work highlights the importance of community context for understanding the origins of coexistence in complex ecosystems.
We demonstrate high-performance, air-stable, low-temperature processed (≤100 °C) semitransparent (ST) perovskite solar cells (PSCs) by the applications of atomic layer deposition (ALD) technology to ...deposit ZnO and Al2O3 films as cathode buffer layer (CBL) and encapsulation layer, respectively. The application of ALD ZnO film as CBL in PSCs delivers several remarkable features, including fine-tunability of the work function of the electrode, low deposition temperature (80 °C), high charge selectivity, good electron-transporting ability (filed-effect mobility = 16.1 cm2 V–1 s–1), and excellent film coverage. With these desired interfacial properties, the device with opaque Ag electrode delivers high power conversion efficiency (PCE) up to 16.5%, greatly outperforming the device with state-of-the-art CBL ZnO nanoparticles film (10.8%). For ST PSCs employing Ag nanowires as transparent top electrode, a remarkable PCE of 10.8% with a corresponding average visible transmittance (AVT) of 25.5% is demonstrated, which represents the highest PCE ever reported for ST PSCs with similar AVT. More significantly, the insufficient ambient stability of ST device is significantly improved by employing excellent gas-barrier performance of ALD Al2O3-based encapsulation layer with an oxygen transmission rate of 1.9 × 10–3 cm3 m–2 day–1 and a water vapor transmittance rate of 9.0 × 10–4 g m–2 day–1.
The effects of coronavirus disease 2019 (COVID-19) primarily concern the respiratory tract and lungs; however, studies have shown that all organs are susceptible to infection by severe acute ...respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 may involve multiorgan damage from direct viral invasion through angiotensin-converting enzyme 2 (ACE2), through inflammatory cytokine storms, or through other secondary pathways. This study involved the analysis of publicly accessible transcriptome data from the Gene Expression Omnibus (GEO) database for identifying significant differentially expressed genes related to COVID-19 and an investigation relating to the pathways associated with mitochondrial, cardiac, hepatic, and renal toxicity in COVID-19. Significant differentially expressed genes were identified and ranked by statistical approaches, and the genes derived by biological meaning were ranked by feature importance; both were utilized as machine learning features for verification. Sample set selection for machine learning was based on the performance, sample size, imbalanced data state, and overfitting assessment. Machine learning served as a verification tool by facilitating the testing of biological hypotheses by incorporating gene list adjustment. A subsequent in-depth study for gene and pathway network analysis was conducted to explore whether COVID-19 is associated with cardiac, hepatic, and renal impairments via mitochondrial infection. The analysis showed that potential cardiac, hepatic, and renal impairments in COVID-19 are associated with ACE2, inflammatory cytokine storms, and mitochondrial pathways, suggesting potential medical interventions for COVID-19-induced multiorgan damage.
3D organic‐inorganic metal halide perovskites are excellent materials for optoelectronic applications due to their exceptional properties, solution processability, and cost‐effectiveness. However, ...the lack of environmental stability highly restricts them from practical applications. Herein, a stable centimeter‐long 2D hybrid perovskite (N‐MPDA)PbBr4 single crystal using divalent N1‐methylpropane‐1,3‐diammonium (N‐MPDA) cation as an organic spacer, is reported. The as‐grown single crystal exhibits stable optoelectronic performance, low threshold random lasing, and multi‐photon luminescence/multi‐harmonic generation. A photoconductive device fabricated using (N‐MPDA)PbBr4 single crystal exhibits an excellent photoresponsivity (≈124 AW−1 at 405 nm) that is ≈4 orders of magnitudes higher than that of monovalent organic spacer‐assisted 2D perovskites, such as (BA)2PbBr4 and (PEA)2PbBr4, and large specific detectivity (≈1012 Jones). As an optical gain media, the (N‐MPDA)PbBr4 single crystal exhibits a low threshold random lasing (≈6.5 µJ cm−2) with angular dependent narrow linewidth (≈0.1 nm) and high‐quality factor (Q ≈ 2673). Based on these results, the outstanding optoelectronic merits of (N‐MPDA)PbBr4 single crystal will offer a high‐performance device and act as a dynamic material to construct stable future electronics and optoelectronic‐based applications.
Asymmetric diammonium di‐cation assisted nonlinear optical 2D (N‐MPDA)PbBr4 hybrid perovskite single crystal shows a stable photodetector performance with high responsivity, large specific detectivity, and functions as an optical gain medial for random lasing with high “Q” factor. The above features promising the asymmetric diammonium spacer will be highly beneficial in advancing 2D perovskite materials for steady optoelectronic applications.
Coupling urea oxidation reaction (UOR) with hydrogen evolution reaction (HER) is an effective energy‐saving technique for hydrogen generation. However, exploring efficient bifunctional ...electrocatalysts under high current density is still challenging. Herein, hierarchical Fe doped cobalt selenide coupled with FeCo layered double hydroxide (Fe‐Co0.85Se/FeCo LDH) array as a self‐supported superior bifunctional heterojunction electrode is rationally designed for both UOR and HER. The unique heterostructure facilitates electron transfer and interface interactions through local interfacial Co‐Se/O‐Fe bonding environment modulation, improving reaction kinetics and intrinsic activity. As a result, the heterostructured electrocatalyst exhibits ultralow potentials of −0.274 and 1.48 V to reach 500 mA cm−2 for catalyzing the HER and UOR, respectively. Particularly, the full urea electrolysis system driven by Fe‐Co0.85Se/FeCo LDH delivers 300 mA cm−2 at a relatively low potential of 1.57 V, which is 150 mV lower than the conventional water electrolysis. The combination of in situ characterization and theoretical analysis reveal that the active sites with the adjustable electronic environment are induced by the interfacial bonding of the heterojunction, facilitating the water decomposition of HER and the stabilization of intermediates in UOR. This work inspires the interfacial environment modulation to optimize advanced electrocatalysts for energy‐saving H2 production.
The heterostructure constructed by Fe doped Co0.85Se and FeCo LDH can induce the modulation of local interfacial bonding environment and optimize the d‐band center to benefit the intermediates adsorption/desorption during urea oxidation reaction. As a result, a low cell voltage of 1.57 V at 300 mA cm−2 for urea water splitting is achieved based on the heterostructure.
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