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1.
Nature ; 602(7898): 612-616, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-35197617

RESUMEN

Future projections of global mean precipitation change (ΔP) based on Earth-system models have larger uncertainties than projections of global mean temperature changes (ΔT)1. Although many observational constraints on ΔT have been proposed, constraints on ΔP have not been well studied2-5 and are often complicated by the large influence of aerosols on precipitation4. Here we show that the upper bound (95th percentile) of ΔP (2051-2100 minus 1851-1900, percentage of the 1980-2014 mean) is lowered from 6.2 per cent to 5.2-5.7 per cent (minimum-maximum range of sensitivity analyses) under a medium greenhouse gas concentration scenario. Our results come from the Coupled Model Intercomparison Project phase 5 and phase 6 ensembles6-8, in which ΔP for 2051-2100 is well correlated with the global mean temperature trends during recent decades after 1980 when global anthropogenic aerosol emissions were nearly constant. ΔP is also significantly correlated with the recent past trends in precipitation when we exclude the tropical land areas with few rain-gauge observations. On the basis of these significant correlations and observed trends, the variance of ΔP is reduced by 8-30 per cent. The observationally constrained ranges of ΔP should provide further reliable information for impact assessments.


Asunto(s)
Modelos Teóricos , Lluvia , Incertidumbre , Aerosoles/provisión & distribución , Actividades Humanas , Temperatura
2.
Nature ; 572(7768): 230-234, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31391559

RESUMEN

Groundwater in sub-Saharan Africa supports livelihoods and poverty alleviation1,2, maintains vital ecosystems, and strongly influences terrestrial water and energy budgets3. Yet the hydrological processes that govern groundwater recharge and sustainability-and their sensitivity to climatic variability-are poorly constrained4,5. Given the absence of firm observational constraints, it remains to be seen whether model-based projections of decreased water resources in dry parts of the region4 are justified. Here we show, through analysis of multidecadal groundwater hydrographs across sub-Saharan Africa, that levels of aridity dictate the predominant recharge processes, whereas local hydrogeology influences the type and sensitivity of precipitation-recharge relationships. Recharge in some humid locations varies by as little as five per cent (by coefficient of variation) across a wide range of annual precipitation values. Other regions, by contrast, show roughly linear precipitation-recharge relationships, with precipitation thresholds (of roughly ten millimetres or less per day) governing the initiation of recharge. These thresholds tend to rise as aridity increases, and recharge in drylands is more episodic and increasingly dominated by focused recharge through losses from ephemeral overland flows. Extreme annual recharge is commonly associated with intense rainfall and flooding events, themselves often driven by large-scale climate controls. Intense precipitation, even during years of lower overall precipitation, produces some of the largest years of recharge in some dry subtropical locations. Our results therefore challenge the 'high certainty' consensus regarding decreasing water resources4 in such regions of sub-Saharan Africa. The potential resilience of groundwater to climate variability in many areas that is revealed by these precipitation-recharge relationships is essential for informing reliable predictions of climate-change impacts and adaptation strategies.


Asunto(s)
Agua Subterránea/análisis , Lluvia , África del Sur del Sahara , Clima Desértico , Sequías/estadística & datos numéricos
3.
Clin Infect Dis ; 78(6): 1690-1697, 2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38563246

RESUMEN

BACKGROUND: Improving health-related quality of life (HRQOL) has emerged as a priority in the management of nontuberculous mycobacterial pulmonary disease (NTM-PD). We aimed to evaluate HRQOL and its changes after 6 months' treatment in patients with NTM-PD. METHODS: The NTM-KOREA is a nationwide prospective cohort enrolling patients initiating treatment for NTM-PD in 8 institutions across South Korea. We conducted the Quality of Life-Bronchiectasis (QOL-B) at 6-month intervals and evaluated baseline scores (higher scores indicate better quality of life) and changes after 6 months' treatment. Multivariate logistic regression was performed to identify factors associated with improvement in the QOL-B physical functioning and respiratory symptoms domains. RESULTS: Between February 2022 and August 2023, 411 patients were included in the analysis. Baseline scores (95% confidence interval [CI]) for physical functioning and respiratory symptoms were 66.7 (46.7-86.7) and 81.5 (70.4-92.6), respectively. Among 228 patients who completed the QOL-B after 6 months' treatment, improvements in physical functioning and respiratory symptoms were observed in 61 (26.8%) and 71 (31.1%) patients, respectively. A lower score (adjusted odds ratio; 95% CI) for physical functioning (0.93; 0.91-0.96) and respiratory symptoms (0.92; 0.89-0.95) at treatment initiation was associated with a greater likelihood of physical functioning and respiratory symptom improvement, respectively; achieving culture conversion was not associated with improvement in physical functioning (0.62; 0.28-1.39) or respiratory symptoms (1.30; 0.62-2.74). CONCLUSIONS: After 6 months of antibiotic treatment for NTM-PD, HRQOL improved in almost one-third, especially in patients with severe initial symptoms, regardless of culture conversion. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov identifier: NCT03934034.


Asunto(s)
Antibacterianos , Infecciones por Mycobacterium no Tuberculosas , Calidad de Vida , Humanos , Masculino , Femenino , Infecciones por Mycobacterium no Tuberculosas/tratamiento farmacológico , Infecciones por Mycobacterium no Tuberculosas/microbiología , República de Corea , Antibacterianos/uso terapéutico , Persona de Mediana Edad , Anciano , Estudios Prospectivos , Micobacterias no Tuberculosas/efectos de los fármacos , Resultado del Tratamiento
4.
Hum Mol Genet ; 31(6): 850-862, 2022 03 21.
Artículo en Inglés | MEDLINE | ID: mdl-34605896

RESUMEN

Amyotrophic lateral sclerosis (ALS)-linked mutations in fused in sarcoma (FUS) lead to the formation of cytoplasmic aggregates in neurons. They are believed to play a critical role in the pathogenesis of FUS-associated ALS. Therefore, the clearance and degradation of cytoplasmic FUS aggregates in neurons may be considered a therapeutic strategy for ALS. However, the molecular pathogenic mechanisms behind FUS-associated ALS remain poorly understood. Here, we report GSK-3ß as a potential modulator of FUS-induced toxicity. We demonstrated that RNAi-mediated knockdown of Drosophila ortholog Shaggy in FUS-expressing flies suppresses defective phenotypes, including retinal degeneration, motor defects, motor neuron degeneration and mitochondrial dysfunction. Furthermore, we found that cytoplasmic FUS aggregates were significantly reduced by Shaggy knockdown. In addition, we found that the levels of FUS proteins were significantly reduced by co-overexpression of Slimb, a F-box protein, in FUS-expressing flies, indicating that Slimb is critical for the suppressive effect of Shaggy/GSK-3ß inhibition on FUS-induced toxicity in Drosophila. These findings revealed a novel mechanism of neuronal protective effect through SCFSlimb-mediated FUS degradation via GSK-3ß inhibition, and provided in vivo evidence of the potential for modulating FUS-induced ALS progression using GSK-3ß inhibitors.


Asunto(s)
Esclerosis Amiotrófica Lateral , Proteínas de Drosophila , Síndromes de Neurotoxicidad , Esclerosis Amiotrófica Lateral/metabolismo , Animales , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Glucógeno Sintasa Quinasa 3 beta/genética , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Mutación , Proteína FUS de Unión a ARN/genética , Proteína FUS de Unión a ARN/metabolismo
5.
Small ; 20(9): e2306781, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37806758

RESUMEN

The defect engineering of inorganic solids has received significant attention because of its high efficacy in optimizing energy-related functionalities. Consequently, this approach is effectively leveraged in the present study to synthesize atomically-thin holey 2D nanosheets of a MoN-Mo5 N6 composite. This is achieved by controlled nitridation of assembled MoS2 monolayers, which induced sequential cation/anion migration and a gradual decrease in the Mo valency. Precise control of the interlayer distance of the MoS2 monolayers via assembly with various tetraalkylammonium ions is found to be crucial for synthesizing sub-nanometer-thick holey MoN-Mo5 N6 nanosheets with a tunable anion/cation vacancy content. The holey MoN-Mo5 N6 nanosheets are employed as efficient immobilization matrices for Pt single atoms to achieve high electrocatalytic mass activity, decent durability, and low overpotential for the hydrogen evolution reaction (HER). In situ/ex situ spectroscopy and density functional theory (DFT) calculations reveal that the presence of cation-deficient Mo5 N6 domain is crucial for enhancing the interfacial interactions between the conductive molybdenum nitride substrate and Pt single atoms, leading to enhanced electron injection efficiency and electrochemical stability. The beneficial effects of the Pt-immobilizing holey MoN-Mo5 N6 nanosheets are associated with enhanced electronic coupling, resulting in improvements in HER kinetics and interfacial charge transfer.

6.
Small ; : e2401480, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38949050

RESUMEN

Azobenzene, while relevant, has faced constraints in biological system applications due to its suboptimal quantum yield and short-wavelength emission. This study presents a pioneering strategy for fabricating organic microdots by coupling foldamer-linked azobenzene, resulting in robust fluorescence intensity and stability, especially in aggregated states, thereby showing promise for bioimaging applications. Comprehensive experimental and computational examinations elucidate the mechanisms underpinning enhanced photostability and fluorescence efficacy. In vitro and in vivo evaluations disclose that the external layer of cis-azo-foldamer microdots performs a self-sacrificial function during photo-bleaching. Consequently, these red-fluorescent microdots demonstrate extraordinary structural and photochemical stabilities over extended periods. The conjugation of a ß-peptide foldamer to the azobenzene chromophore through a glycine linker instigates a blue-shifted and amplified π*-n transition. Molecular dynamics simulations reveal that the aggregated state of cis-azo-foldamers fortifies the stability of cis isomers, thereby augmenting fluorescence efficiency. This investigation furnishes crucial insights into conceptualizing novel, biologically inspired materials, promising stable and enduring imaging applications, and carries implications for diverse arenas such as medical diagnostics, drug delivery, and sensing technologies.

7.
Nat Mater ; 22(12): 1470-1477, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38012388

RESUMEN

Three-dimensional (3D) hetero-integration technology is poised to revolutionize the field of electronics by stacking functional layers vertically, thereby creating novel 3D circuity architectures with high integration density and unparalleled multifunctionality. However, the conventional 3D integration technique involves complex wafer processing and intricate interlayer wiring. Here we demonstrate monolithic 3D integration of two-dimensional, material-based artificial intelligence (AI)-processing hardware with ultimate integrability and multifunctionality. A total of six layers of transistor and memristor arrays were vertically integrated into a 3D nanosystem to perform AI tasks, by peeling and stacking of AI processing layers made from bottom-up synthesized two-dimensional materials. This fully monolithic-3D-integrated AI system substantially reduces processing time, voltage drops, latency and footprint due to its densely packed AI processing layers with dense interlayer connectivity. The successful demonstration of this monolithic-3D-integrated AI system will not only provide a material-level solution for hetero-integration of electronics, but also pave the way for unprecedented multifunctional computing hardware with ultimate parallelism.

8.
J Chem Phys ; 160(2)2024 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-38189606

RESUMEN

Alkoxide precursors have been highlighted for depositing carbon-free films, but their use in Atomic Layer Deposition (ALD) often exhibits a non-saturated growth. This indicates no self-limiting growth due to the chain reaction of hydrolysis or ligand decomposition caused by ß-hydride elimination. In the previous study, we demonstrated that self-limiting growth of ALD can be achieved using our newly developed precursor, hafnium cyclopentadienyl tris(N-ethoxy-2,2-dimethyl propanamido) [HfCp(edpa)3]. To elucidate the growth mechanism and the role of cyclopentadienyl (Cp) ligand in a heteroleptic alkoxide precursor, herein, we compare homoleptic and heteroleptic Hf precursors consisting of N-ethoxy-2,2-dimethyl propanamido (edpa) ligands with and without cyclopentadienyl ligand-hafnium tetrakis(N-ethoxy-2,2-dimethyl propanamido) [Hf(edpa)4] and HfCp(edpa)3. We also investigate the role of a Cp ligand in growth characteristics. By substituting an alkoxide ligand with a Cp ligand, we could modify the surface reaction during ALD, preventing undesired reactions. The last remaining edpa after Hf(edpa)4 adsorption can undergo a hydride elimination reaction, resulting in surface O-H generation. In contrast, Cp remains after the HfCp(edpa)3 adsorption. Accordingly, we observe proper ALD growth with self-limiting properties. Thus, a comparative study of different ligands of the precursors can provide critical clues to the design of alkoxide precursors for obtaining typical ALD growth with a saturation behavior.

9.
J Chem Phys ; 160(10)2024 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-38456534

RESUMEN

Molybdenum disulfide (MoS2), a semiconducting two-dimensional layered transition metal dichalcogenide (2D TMDC), with attractive properties enables the opening of a new electronics era beyond Si. However, the notoriously high contact resistance (RC) regardless of the electrode metal has been a major challenge in the practical applications of MoS2-based electronics. Moreover, it is difficult to lower RC because the conventional doping technique is unsuitable for MoS2 due to its ultrathin nature. Therefore, the metal-insulator-semiconductor (MIS) architecture has been proposed as a method to fabricate a reliable and stable contact with low RC. Herein, we introduce a strategy to fabricate MIS contact based on atomic layer deposition (ALD) to dramatically reduce the RC of single-layer MoS2 field effect transistors (FETs). We utilize ALD Al2O3 as an interlayer for the MIS contact of bottom-gated MoS2 FETs. Based on the Langmuir isotherm, the uniformity of ALD Al2O3 films on MoS2 can be increased by modulating the precursor injection pressures even at low temperatures of 150 °C. We discovered, for the first time, that film uniformity critically affects RC without altering the film thickness. Additionally, we can add functionality to the uniform interlayer by adopting isopropyl alcohol (IPA) as an oxidant. Tunneling resistance across the MIS contact is lowered by n-type doping of MoS2 induced by IPA as the oxidant in the ALD process. Through a highly uniform interlayer combined with strong doping, the contact resistance is improved by more than two orders of magnitude compared to that of other MoS2 FETs fabricated in this study.

10.
BMC Pulm Med ; 24(1): 7, 2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38166950

RESUMEN

BACKGROUND: Bacterial colonization is an essential aspect of bronchiectasis. Although Haemophilus influenzae is a frequent colonizer in some regions, its clinical impacts are poorly understood. This study aimed to elucidate the impact of H. influenzae colonization in patients with bronchiectasis. METHODS: This retrospective study screened adult patients diagnosed with bronchiectasis at a tertiary referral center between April 1, 2003, and May 16, 2021, in South Korea. Propensity score matching was used to match patients with and without H. influenzae colonization. We assessed the severity of bronchiectasis as per the bronchiectasis severity index, the incidence of exacerbation, differences in lung function, and all-cause mortality. RESULTS: Out of the 4,453 patients with bronchiectasis, 79 (1.8%) were colonized by H. influenzae. After 1:2 propensity score matching, 78 and 154 patients were selected from the H. influenzae colonizer and non-colonizer groups, respectively. Although there were no significant differences between the groups regarding baseline demographics, patients colonized with H. influenzae had a higher bronchiectasis severity index (median 6 [interquartile range 4-8] vs. 4 [2-7], p = 0.002), associated with extensive radiographic involvement (52.2% vs. 37.2%, p = 0.045) and mild exacerbation without hospitalization (adjusted incidence rate ratio 0.15; 95% confidence interval 0.12-0.24). Lung function and mortality rates did not reveal significant differences, regardless of H. influenzae colonization. CONCLUSION: H. influenzae colonization in bronchiectasis was associated with more severe disease and greater incidence of mild exacerbation, but not lung function and mortality. Attention should be paid to patients with bronchiectasis with H. influenzae colonization.


Asunto(s)
Bronquiectasia , Haemophilus influenzae , Adulto , Humanos , Estudios Retrospectivos , Bronquiectasia/complicaciones , República de Corea/epidemiología
11.
Nano Lett ; 23(9): 3788-3795, 2023 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-37126862

RESUMEN

Dielectric capacitors have greater power densities than batteries, and, unlike batteries, they do not utilize chemical reactions during cycling. Thus, they can become ideal, safe energy storage devices. However, dielectric capacitors yield rather low energy densities compared with other energy storage devices such as batteries and supercapacitors. Here, we present a rational approach for designing ultrahigh energy storage capacitors using two-dimensional (2D) high-κ dielectric perovskites (Ca2Nam-3NbmO3m+1; m = 3-6). Individual Ca2Nam-3NbmO3m+1 nanosheets exhibit an ultrahigh dielectric strength (638-1195 MV m-1) even in the monolayer form, which exceeds those of conventional dielectric materials. Multilayer stacked nanosheet capacitors exhibit ultrahigh energy densities (174-272 J cm-3), high efficiencies (>90%), excellent reliability (>107 cycles), and temperature stability (-50-300 °C); the maximum energy density is much higher than those of conventional dielectric materials and even comparable to those of lithium-ion batteries. Enhancing the energy density may make dielectric capacitors more competitive with batteries.

12.
J Am Chem Soc ; 145(20): 11364-11374, 2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37183414

RESUMEN

Ru catalysts promoted with alkali and alkaline earth have shown superior ammonia (NH3) synthesis activities under mild conditions. Although these promoters play a vital role in enhancing catalytic activity, their function has not been clearly understood. Here, we synthesize a series of Ba-Ru/MgO catalysts with an optimal Ru particle size (∼2.3 nm) and tailored BaO-Ru interfacial structures. We discover that the promoting effect is created through the separate storage of H+/e- pairs at the BaO-Ru interface. Chemisorbed H atoms on Ru dissociate into H+/e- pairs at the BaO-Ru interface, where strongly basic, nonreducible BaO selectively captures H+ while leaving e- on Ru. The resulting electron accumulation in Ru facilitates N2 activation via enhanced π-backdonation and inhibits hydrogen poisoning during NH3 synthesis. Consequently, the formation of intimate BaO-Ru interface without an excessive loss of accessible Ru sites enables the synthesis of highly active catalysts for NH3 synthesis.

13.
J Am Chem Soc ; 145(36): 19812-19823, 2023 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-37656929

RESUMEN

Singlet exciton fission in organic chromophores has received much attention during the past decade. Inspired by numerous spectroscopic studies in the solid state, there have been vigorous efforts to study singlet exciton fission dynamics in covalently bonded oligomers, which aims to investigate underlying mechanisms of this intriguing process in simplified model systems. In terms of through-space orbital interactions, however, most of covalently bonded pentacene oligomers studied so far fall into weakly interacting systems since they manifest chain-like structures based on various (non)conjugated linkers. Therefore, it remains as a compelling question to answer how through-space interactions in the solid state intervene this photophysical process since it is hypersensitive to displacements and orientations between neighboring chromophores. Herein, as one of experimental studies to answer this question, we introduced a tight-packing dendritic structure whose mesityl-pentacene constituents are coupled via moderate through-space orbital interactions. Based on the comparison with a suitably controlled dendritic structure, which is in a weak coupling regime, important mechanistic viewpoints are tackled such as configurational mixings between singlet, charge-transfer, and triplet pair states and the role of chromophore multiplication. We underscore that our through-space-coupled dendritic oligomer in a quasi-intermediate coupling regime provides a hint on the interplay of multiconfigurational excited-states, which might have drawn complexity in singlet exciton fission kinetics throughout numerous solid-state morphologies.

14.
J Am Chem Soc ; 145(49): 26632-26644, 2023 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-38047734

RESUMEN

The water oxidation reaction, the most important reaction for hydrogen production and other sustainable chemistry, is efficiently catalyzed by the Mn4CaO5 cluster in biological photosystem II. However, synthetic Mn-based heterogeneous electrocatalysts exhibit inferior catalytic activity at neutral pH under mild conditions. Symmetry-broken Mn atoms and their cooperative mechanism through efficient oxidative charge accumulation in biological clusters are important lessons but synthesis strategies for heterogeneous electrocatalysts have not been successfully developed. Here, we report a crystallographically distorted Mn-oxide nanocatalyst, in which Ir atoms break the space group symmetry from I41/amd to P1. Tetrahedral Mn(II) in spinel is partially replaced by Ir, surprisingly resulting in an unprecedented crystal structure. We analyzed the distorted crystal structure of manganese oxide using TEM and investigated how the charge accumulation of Mn atoms is facilitated by the presence of a small amount of Ir.

15.
Hum Mol Genet ; 30(19): 1797-1810, 2021 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-34077532

RESUMEN

Spinocerebellar ataxia type 2 is a polyglutamine (polyQ) disease associated with an expanded polyQ domain within the protein product of the ATXN2 gene. Interestingly, polyQ repeat expansions in ATXN2 are also associated with amyotrophic lateral sclerosis (ALS) and parkinsonism depending upon the length of the polyQ repeat expansion. The sequence encoding the polyQ repeat also varies with disease presentation: a pure CAG repeat is associated with SCA2, whereas the CAG repeat in ALS and parkinsonism is typically interrupted with the glutamine encoding CAA codon. Here, we asked if the purity of the CAG sequence encoding the polyQ repeat in ATXN2 could impact the toxicity of the ataxin-2 protein in vivo in Drosophila. We found that ataxin-2 encoded by a pure CAG repeat conferred toxicity in the retina and nervous system, whereas ataxin-2 encoded by a CAA-interrupted repeat or CAA-only repeat failed to confer toxicity, despite expression of the protein at similar levels. Furthermore, the CAG-encoded ataxin-2 protein aggregated in the fly eye, while ataxin-2 encoded by either a CAA/G or CAA repeat remained diffuse. The toxicity of the CAG-encoded ataxin-2 protein was also sensitive to the translation factor eIF4H, a known modifier of the toxic GGGGCC repeat in flies. These data indicate that ataxin-2 encoded by a pure CAG versus interrupted CAA/G polyQ repeat domain is associated with differential toxicity, indicating that mechanisms associated with the purity of the sequence of the polyQ domain contribute to disease.


Asunto(s)
Esclerosis Amiotrófica Lateral , Ataxias Espinocerebelosas , Esclerosis Amiotrófica Lateral/genética , Animales , Ataxina-2/genética , Ataxina-3/genética , Ataxinas/genética , Drosophila/genética , Ataxias Espinocerebelosas/genética , Expansión de Repetición de Trinucleótido/genética
16.
Hum Mol Genet ; 30(12): 1084-1100, 2021 06 09.
Artículo en Inglés | MEDLINE | ID: mdl-33783499

RESUMEN

RNA-binding proteins (RBPs) play essential roles in diverse cellular processes through post-transcriptional regulation of RNAs. The subcellular localization of RBPs is thus under tight control, the breakdown of which is associated with aberrant cytoplasmic accumulation of nuclear RBPs such as TDP-43 and FUS, well-known pathological markers for amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). Here, we report in Drosophila model for ALS/FTD that nuclear accumulation of a cytoplasmic RBP Staufen may be a new pathological feature. We found that in Drosophila C4da neurons expressing PR36, one of the arginine-rich dipeptide repeat proteins (DPRs), Staufen accumulated in the nucleus in Importin- and RNA-dependent manner. Notably, expressing Staufen with exogenous NLS-but not with mutated endogenous NLS-potentiated PR-induced dendritic defect, suggesting that nuclear-accumulated Staufen can enhance PR toxicity. PR36 expression increased Fibrillarin staining in the nucleolus, which was enhanced by heterozygous mutation of stau (stau+/-), a gene that codes Staufen. Furthermore, knockdown of fib, which codes Fibrillarin, exacerbated retinal degeneration mediated by PR toxicity, suggesting that increased amount of Fibrillarin by stau+/- is protective. stau+/- also reduced the amount of PR-induced nuclear-accumulated Staufen and mitigated retinal degeneration and rescued viability of flies expressing PR36. Taken together, our data show that nuclear accumulation of Staufen in neurons may be an important pathological feature contributing to the pathogenesis of ALS/FTD.


Asunto(s)
Esclerosis Amiotrófica Lateral/genética , Proteínas de Unión al ADN/genética , Proteínas de Drosophila/genética , Demencia Frontotemporal/genética , Ribonucleoproteína Heterogénea-Nuclear Grupo F-H/genética , Proteínas de Unión al ARN/genética , ARN/genética , Esclerosis Amiotrófica Lateral/patología , Animales , Arginina/genética , Proteína C9orf72/genética , Núcleo Celular/genética , Citoplasma/genética , Dipéptidos/genética , Modelos Animales de Enfermedad , Drosophila melanogaster/genética , Demencia Frontotemporal/patología , Técnicas de Silenciamiento del Gen , Humanos , Neuronas/metabolismo , Neuronas/patología , Señales de Localización Nuclear/genética , Procesamiento Postranscripcional del ARN/genética
17.
Small ; 19(39): e2302418, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37236206

RESUMEN

Despite the optoelectronic similarities between tin and lead halide perovskites, the performance of tin-based perovskite solar cells remains far behind, with the highest reported efficiency to date being ≈14%. This is highly correlated to the instability of tin halide perovskite, as well as the rapid crystallization behavior in perovskite film formation. In this work, l-Asparagine as a zwitterion plays a dual role in controlling the nucleation/crystallization process and improving the morphology of perovskite film. Furthermore, tin perovskites with l-Asparagine show more favorable energy-level matching, enhancing the charge extraction and minimizing the charge recombination, leading to an enhanced power conversion efficiency of 13.31% (from 10.54% without l-Asparagine) with remarkable stability. These results are also in good agreement with the density functional theory calculations. This work not only provides a facile and efficient approach to controlling the crystallization and morphology of perovskite film but also offers guidelines for further improved performance of tin-based perovskite electronic devices.

18.
J Neurogenet ; 37(1-2): 10-19, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36000467

RESUMEN

Tau is a microtubule-associated protein that forms insoluble filaments that accumulate as neurofibrillary tangles in neurodegenerative diseases such as Alzheimer's disease and other related tauopathies. A relationship between abnormal Tau accumulation and ubiquitin-proteasome system impairment has been reported. However, the molecular mechanism linking Tau accumulation and ubiquitin proteasome system (UPS) dysfunction remains unclear. Here, we show that overexpression of wild-type or mutant (P301L) Tau increases the abundance of polyubiquitinated proteins and activates the autophagy-lysosome pathway in mammalian neuronal cells. Previous studies found that PTK2 inhibition mitigates toxicity induced by UPS impairment. Thus, we investigated whether PTK2 inhibition can attenuate Tau-induced UPS impairment and cell toxicity. We found that PTK2 inhibition significantly reduces Tau-induced death in mammalian neuronal cells. Moreover, overexpression of WT or mutant Tau increased the phosphorylation levels of PTK2 and p62. We also confirmed that PTK2 inhibition suppresses Tau-induced phosphorylation of PTK2 and p62. Furthermore, PTK2 inhibition significantly attenuated the climbing defect and shortened the lifespan in the Drosophila model of tauopathy. In addition, we observed that phosphorylation of p62 is markedly increased in Alzheimer's disease patients with tauopathies. Taken together, our results indicate that the UPS dysfunction induced by Tau accumulation might contribute directly to neurodegeneration in tauopathies and that PTK2 could be a promising therapeutic target for tauopathies.


Asunto(s)
Enfermedad de Alzheimer , Tauopatías , Animales , Enfermedad de Alzheimer/metabolismo , Proteínas tau/metabolismo , Fosforilación , Complejo de la Endopetidasa Proteasomal/metabolismo , Tauopatías/metabolismo , Ubiquitinas/metabolismo , Mamíferos/metabolismo
19.
Phys Chem Chem Phys ; 25(10): 7466-7476, 2023 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-36848062

RESUMEN

With the introduction of artificial peptides as antimicrobial agents and organic catalysts, numerous efforts have been made to design foldamers with desirable structures and functions. Computational tools are a helpful proxy for revealing the dynamic structures at atomic resolution and understanding foldamer's complex structure-function relationships. However, the performance of conventional force fields in predicting the structures of artificial peptides has not been systematically evaluated. In this study, we critically assessed three popular force fields, AMBER ff14SB, CHARMM36m, and OPLS-AA/L, in predicting conformational propensities of a ß-peptide foldamer at monomer and hexamer levels. Simulation results were compared to those obtained from quantum chemistry calculations and experimental data. We also utilised replica exchange molecular dynamics simulations to investigate the energy landscape of each force field and assess the similarities and differences between force fields. We compared different solvent systems in the AMBER ff14SB and CHARMM36m frameworks and confirmed the unanimous role of hydrogen bonds in shaping energy landscapes. We anticipate that our data will pave the way for further improvements to force fields and for understanding the role of solvents in peptide folding, crystallisation, and engineering.


Asunto(s)
Aminoácidos , Simulación de Dinámica Molecular , Cristalización , Enlace de Hidrógeno , Péptidos , Solventes
20.
J Chem Phys ; 159(19)2023 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-37966459

RESUMEN

Probing the chemistry and materials science of electrochemical energy materials is a central topic in both chemical physics and energy chemistry due to the increasingly important role of energy devices in the current and future energy system and industry. Especially, understanding the chemical physics of electrochemical energy materials is the key to enhance the performance of energy storage and conversion devices such as batteries, fuel cells, electrolyzers, and supercapacitors. This special topic focuses on the fundamental understanding of electrochemical energy applications, including electrochemistry fundamentals, structural dynamics and degradation mechanism of materials, optimization strategies for improving electrochemical performance of energy devices, and emerging simulation and characterization methods applied to advanced energy materials.

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