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Highly stable perovskite solar cells with 0.30 voltage deficit enabled by a multi-functional asynchronous cross-linking.
No full textThe primary challenge in commercializing perovskite solar cells (PSCs) mainly stems from fragile and moisture-sensitive nature of halide perovskite materials. In this study, we propose an asynchronous cross-linking strategy. A multifunctional cross-linking initiator, divinyl sulfone (DVS), is firstly pre-embedded into perovskite precursor solutions. DVS, also as a special co-solvent, facilitates intermediate-dominated perovskite crystallization manipulation, favouring formamidine-DVS based solvate transition. Subsequently, DVS-embedded perovskite as-cast films are post-treated with a nucleophilic reagent, glycerinum, to trigger controllably three-dimensional co-polymerization. The resulting cross-linking scaffold provides enhanced water-resistance, releases residual tensile strain, and suppresses deep-level defects. We achieve a maximum efficiency over 25% (certified 24.6%) and a maximum VOC of 1.229 V, corresponding to mere 0.30 V deficit, reaching 97.5% of the theoretical limit, which is the highest reported in all perovskite systems. This strategy is generally applicable with enhanced efficiencies approaching 26%. All-around protection significantly improves PSCs operational longevity and thermal endurance
Contrasting demographic processes underlie uphill shifts in a desert ecosystem.
Full text linkClimate change is projected to cause extensive plant range shifts, and, in many cases such shifts already are underway. Most long-term studies of range shifts measure emergent changes in species distributions but not the underlying demographic patterns that shape them. To better understand species elevational range shifts and their underlying demographic processes, we use the powerful approach of rephotography, comparing historical (1978-1982) and modern (2015-2016) photographs taken along a 1000-m elevational gradient in the Colorado Desert of Southern California. This approach allowed us to track demographic outcomes for 4263 individual plants of 11 long-lived, perennial species over the past ~36 years. All species showed an upward shift in mean elevation (average = 45 m), consistent with observed increasing temperature and severe drought in the region. We found that varying demographic processes underlaid these elevational shifts, with some species showing higher recruitment and some showing higher survival with increasing elevation. Species with faster life-history rates (higher background recruitment and mortality rates) underwent larger elevational shifts. Our findings emphasize the importance of demography and life history in shaping range shift responses and future community composition, as well as the sensitivity of desert systems to climate change despite the typical slow motion population dynamics of perennial desert plants
Intestinal pathology in goats challenged with Clostridium perfringens type D strain CN1020 wild-type and its genetically modified derivatives.
Full text linkClostridium perfringens type D is the causative agent of enterotoxemia in sheep, goats, and cattle. Although in sheep and cattle, the disease is mainly characterized by neurological clinical signs and lesions, goats with type D enterotoxemia frequently have alterations of the alimentary system. Epsilon toxin (ETX) is the main virulence factor of C. perfringens type D, although the role of ETX in intestinal lesions in goats with type D enterotoxemia has not been fully characterized. We evaluated the contribution of ETX to C. perfringens type D enteric pathogenicity using an intraduodenal challenge model in young goats, with the virulent C. perfringens type D wild-type strain CN1020; its isogenic etx null mutant; an etx-complemented strain; and sterile, non-toxic culture medium. The intestinal tract of each animal was evaluated grossly, microscopically, and immunohistochemically for activated caspase-3. Both ETX-producing strains induced extensive enterocolitis characterized by severe mucosal necrosis, apoptosis, and diffuse suppurative infiltrates. No significant gross or microscopic lesions were observed in goats inoculated with the non-ETX-containing inocula. These results confirm that ETX is essential for the production of intestinal lesions in goats with type D disease. Also, our results suggest that the intestinal pathology of type D enterotoxemia in goats is, at least in part, associated with apoptosis
Treatment of traumatic disruption of the suspensory apparatus in Thoroughbred racehorses at risk of proximal interphalangeal joint subluxation using a locking compression-distal femur plate for double arthrodesis.
Full text linkOBJECTIVE: To describe the outcome of metacarpophalangeal (MCPJ) and proximal interphalangeal joint (PIPJ) arthrodesis using a locking compression-distal femur plate (LCP-DFP) in Thoroughbred racehorses with traumatic disruption of the suspensory apparatus (TDSA) at risk of PIPJ subluxation. STUDY DESIGN: Multicenter retrospective study. ANIMALS: Twenty-six Thoroughbred racehorses. METHODS: Records of Thoroughbred racehorses with TDSA that had undergone MCPJ and PIPJ arthrodesis using an LCP-DFP at three referral hospitals between 2020 and 2024 were reviewed for inclusion. The preoperative data collected included signalment, affected limb, and type of injury. All postoperative complications were recorded. Long-term outcomes were obtained from medical records and telephone interviews. RESULTS: Nine females, 14 geldings, and three intact males with TDSA were treated via double arthrodesis using an LCP-DFP. The most common postoperative complications included support limb laminitis, incisional drainage, implant infection with osteomyelitis, and distal interphalangeal joint subluxation. No horses developed PIPJ subluxation. Twenty (76.9%) horses developed short-term complications. Thirteen (50%) horses survived long term (>6 months, range 6-32 months) and were reported to be pasture sound without receiving any analgesic or antiinflammatory medication. CONCLUSION: Metacarpophalangeal and PIPJ arthrodesis using an LCP-DFP in racehorses resulted in a stable construct with no horses developing subluxation of the PIPJ joint postoperatively. Arthrodesis using an LCP-DFP was associated with a fair prognosis for pasture soundness. CLINICAL SIGNIFICANCE: Application of an LCP-DFP may prevent subluxation of the PIPJ; however, the prognosis is still affected by the high prevalence of other complications and associated mortality among horses that suffer TDSA
Disturbed sleep after lung transplantation is associated with worse patient-reported outcomes and chronic lung allograft dysfunction.
Full text linkBACKGROUND: Many lung transplant recipients fail to derive the expected improvements in health-related quality of life (HRQL) and survival. Sleep may represent an important, albeit rarely examined, factor associated with lung transplant outcomes. METHODS: Within a larger cohort study, 141 lung transplant recipients completed the Medical Outcomes Study Sleep Problems Index (SPI) Revised scale along with a broader survey of patient-reported outcome (PRO) measures and frailty assessment. From the SPI, we also derived an insomnia-specific subscale. Potential perioperative risk factors for disturbed sleep were derived from medical records. We investigated associations between perioperative predictors on SPI and insomnia and associations between SPI and insomnia on PROs and frailty by linear regressions, adjusting for age, sex, and lung function. We evaluated the associations between SPI and insomnia on time to chronic lung allograft dysfunction (CLAD) and death using Cox models, adjusting for age, sex, and transplant indication. RESULTS: Post-transplant hospital length of stay >30 days was associated with worse sleep by SPI and insomnia (SPI: p = 0.01; insomnia p = 0.02). Worse sleep by SPI and insomnia was associated with worse depression, cognitive function, HRQL, physical disability, health utilities, and Fried Frailty Phenotype frailty (all p < 0.01). Those in the worst quartile of SPI and insomnia exhibited an increased risk of CLAD (hazard ratio [HR] 2.18; 95% confidence interval [CI]: 1.22-3.89; p = 0.01 for SPI and HR 1.96; 95%CI 1.09-3.53; p = 0.03 for insomnia). Worsening in SPI but not insomnia was also associated with mortality (HR: 1.29; 95%CI: 1.05-1.58; p = 0.01). CONCLUSIONS: Poor sleep after lung transplant appears associated with PROs, frailty, CLAD, and death. Clarifying the nature of this association may have important screening implications
The Miscibility of Hydrogen and Water in Planetary Atmospheres and Interiors
Full text linkAbstract:
Many planets in the solar system and across the Galaxy have hydrogen-rich atmospheres overlying more heavy element-rich interiors with which they interact for billions of years. Atmosphere–interior interactions are thus crucial to understanding the formation and evolution of these bodies. However, this understanding is still lacking in part because the relevant pressure–temperature conditions are extreme. We conduct molecular dynamics simulations based on density functional theory to investigate how hydrogen and water interact over a wide range of pressure and temperature, encompassing the interiors of Neptune-sized and smaller planets. We determine the critical curve at which a single homogeneous phase exsolves into two separate hydrogen-rich and water-rich phases, finding good agreement with existing experimental data. We find that the temperature along the critical curve increases with increasing pressure and shows the influence of a change in fluid structure from molecular to atomic near 30 GPa and 3000 K, which may impact magnetic field generation. The internal temperatures of many exoplanets, including TOI-270 d and K2-18 b, may lie entirely above the critical curve: the envelope is expected to consist of a single homogeneous hydrogen–water fluid, which is much less susceptible to atmospheric loss as compared with a pure hydrogen envelope. As planets cool, they cross the critical curve, leading to rainout of water-rich fluid and an increase in internal luminosity. Compositions of the resulting outer, hydrogen-rich and inner, water-rich envelopes depend on age and instellation and are governed by thermodynamics. Rainout of water may be occurring in Uranus and Neptune at present
Phase Change-Mediated Capture of Carbon Dioxide from Air with a Molecular Triamine Network Solid
Full text linkThe efficient removal of CO2 from exhaust streams and even directly from air is necessary to forestall climate change, lending urgency to the search for new materials that can rapidly capture CO2 at high capacity. The recent discovery that diamine-appended metal-organic frameworks can exhibit cooperative CO2 uptake via the formation of ammonium carbamate chains begs the question of whether simple organic polyamine molecules could be designed to achieve a similar switch-like behavior with even higher separation capacities. Here, we present a solid molecular triamine, 1,3,5-tris(aminomethyl)benzene (TriH), that rapidly captures large quantities of CO2 upon exposure to humid air to form the porous, crystalline, ammonium carbamate network solid TriH(CO2)1.5·xH2O (TriHCO2). The phase transition behavior of TriH converting to TriHCO2 was studied through powder and single-crystal X-ray diffraction analysis, and additional spectroscopic techniques further verified the formation of ammonium carbamate species upon exposing TriH to humid air. Detailed breakthrough analyses conducted under varying temperatures, relative humidities, and flow rates reveal record CO2 absorption capacities as high as 8.9 mmol/g. Computational analyses reveal an activation barrier associated with TriH absorbing CO2 under dry conditions that is lowered under humid conditions through hydrogen bonding with a water molecule in the transition state associated with N-C bond formation. These results highlight the prospect of tunable molecular polyamines as a new class of candidate absorbents for high-capacity CO2 capture
Hierarchical Assembly of Conductive Fibers from Coiled-Coil Peptide Building Blocks
Full text linkBiology provides many sources of inspiration for synthetic and multifunctional nanomaterials. Naturally evolved proteins exhibit specialized, sequence-defined functions and self-assembly behavior. Recapitulating their molecularly defined self-assembly behavior, however, is challenging in de novo proteins. Peptides, on the other hand, represent a more well-defined and rationally designable space with the potential for sequence-programmable, stimuli-responsive design for structure and function, making them ideal building blocks of bioelectronic interfaces. In this work, we design peptides that exhibit stimuli-responsive self-assembly and the capacity to transport electrical current over micrometer-long distances. A lysine-lysine (KK) motif inserted at solvent-exposed positions of a coiled-coil-forming peptide sequence introduces pH-dependent control over a transition from unordered to α-helical peptide structure. The ordered state of the peptide serves as a building block for the assembly of coiled coils and higher-order assemblies. Cryo-EM structures of these structures reveal a hierarchical organization of α-helical peptides in a cross coiled coil (CCC) arrangement. Structural analysis also reveals a β-sheet fiber phase under certain conditions and placements of the KK motif, revealing a complex and sensitive self-assembly pathway. Both solid-state and solution-based electrochemical characterizations show that CCC fibers are electronically conductive. Single-fiber conductive AFM measurement indicates that the solid-state electrical conductivity is comparable with bacterial cytochrome filaments. Solution-deposited fiber films approximately doubled the electroactive surface area of the electrode, confirming their conductivity in aqueous environments. This work establishes a stimuli-responsive peptide sequence element for balancing the order-disorder transitions in peptides to control their self-assembly into highly organized electronically conductive nanofibers
Project Prometheus
Full text linkProject Prometheus aims to combat wildfires through early detection using low cost, solar powered, mass deployable sensor modules that communicate via LoRA. Data collected from these modules will be aggregated by an overhead UAV, where a series of advanced machine learning models are employed to analyze sensor data, in combination with local weather station data in order to provide a proactive approach to wildfire management, enabling timely intervention and mitigating property and environmental damag
Weathering the Storm: How Age and Biologics Influence the COVID-19 Cytokine Surge
Full text linkSARS-CoV-2, first identified in December 2019, caused a global pandemic, resulting in over 6.8 million deaths by March 2023. The elderly, or individuals over 65, accounted for the majority of COVID-19 deaths, with 81% of fatalities in the US in 2020 occurring in this group. Beyond mortality, aging populations are also at higher risk of long-term cardiovascular complications and acute respiratory distress syndrome (ARDS). Although these outcomes may be influenced by comorbidities common in the elderly, age has been found to be a standalone risk factor for severe COVID-19 infection. Therefore, investigating age-related factors in COVID-19 outcomes is crucial in protecting this vulnerable group. Of particular interest is the cytokine storm phenomenon, an excessive inflammatory response that contributes to severe COVID-19 symptoms, including ARDS and cardiovascular damage. Elevated levels of multiple cytokines are common in severe cases of COVID-19. We propose that changes that occur to cytokine profiles as we age may contribute to these aberrant inflammatory responses. This review specifically explored the interleukin class cytokines IL-1, IL-6, IL-17, and IL-23 and considered the potential of biologics targeting these cytokines to alleviate severe outcomes in both COVID-19 and aging individuals