Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.945
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Immunity ; 54(10): 2338-2353.e6, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34534439

RESUMO

In tumors, a subset of CD8+ T cells expressing the transcription factor TCF-1 drives the response to immune checkpoint blockade. We examined the mechanisms that maintain these cells in an autochthonous model of lung adenocarcinoma. Longitudinal sampling and single-cell sequencing of tumor-antigen specific TCF-1+ CD8+ T cells revealed that while intratumoral TCF-1+ CD8+ T cells acquired dysfunctional features and decreased in number as tumors progressed, TCF-1+ CD8+ T cell frequency in the tumor draining LN (dLN) remained stable. Two discrete intratumoral TCF-1+ CD8+ T cell subsets developed over time-a proliferative SlamF6+ subset and a non-cycling SlamF6- subset. Blocking dLN egress decreased the frequency of intratumoral SlamF6+ TCF-1+ CD8+ T cells. Conventional type I dendritic cell (cDC1) in dLN decreased in number with tumor progression, and Flt3L+anti-CD40 treatment recovered SlamF6+ T cell frequencies and decreased tumor burden. Thus, cDC1s in tumor dLN maintain a reservoir of TCF-1+ CD8+ T cells and their decrease contributes to failed anti-tumor immunity.


Assuntos
Adenocarcinoma de Pulmão/imunologia , Linfócitos T CD8-Positivos/imunologia , Células Dendríticas/imunologia , Neoplasias Pulmonares/imunologia , Linfonodos/imunologia , Fator 1 de Transcrição de Linfócitos T/imunologia , Animais , Camundongos , Subpopulações de Linfócitos T/imunologia
2.
Nature ; 628(8008): 596-603, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38509371

RESUMO

Motor neurons are the final common pathway1 through which the brain controls movement of the body, forming the basic elements from which all movement is composed. Yet how a single motor neuron contributes to control during natural movement remains unclear. Here we anatomically and functionally characterize the individual roles of the motor neurons that control head movement in the fly, Drosophila melanogaster. Counterintuitively, we find that activity in a single motor neuron rotates the head in different directions, depending on the starting posture of the head, such that the head converges towards a pose determined by the identity of the stimulated motor neuron. A feedback model predicts that this convergent behaviour results from motor neuron drive interacting with proprioceptive feedback. We identify and genetically2 suppress a single class of proprioceptive neuron3 that changes the motor neuron-induced convergence as predicted by the feedback model. These data suggest a framework for how the brain controls movements: instead of directly generating movement in a given direction by activating a fixed set of motor neurons, the brain controls movements by adding bias to a continuing proprioceptive-motor loop.


Assuntos
Drosophila melanogaster , Neurônios Motores , Movimento , Postura , Propriocepção , Animais , Drosophila melanogaster/anatomia & histologia , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Retroalimentação Fisiológica/fisiologia , Cabeça/fisiologia , Modelos Neurológicos , Neurônios Motores/fisiologia , Movimento/fisiologia , Postura/fisiologia , Propriocepção/genética , Propriocepção/fisiologia , Masculino
3.
Nature ; 613(7944): 534-542, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36599984

RESUMO

To survive, animals must convert sensory information into appropriate behaviours1,2. Vision is a common sense for locating ethologically relevant stimuli and guiding motor responses3-5. How circuitry converts object location in retinal coordinates to movement direction in body coordinates remains largely unknown. Here we show through behaviour, physiology, anatomy and connectomics in Drosophila that visuomotor transformation occurs by conversion of topographic maps formed by the dendrites of feature-detecting visual projection neurons (VPNs)6,7 into synaptic weight gradients of VPN outputs onto central brain neurons. We demonstrate how this gradient motif transforms the anteroposterior location of a visual looming stimulus into the fly's directional escape. Specifically, we discover that two neurons postsynaptic to a looming-responsive VPN type promote opposite takeoff directions. Opposite synaptic weight gradients onto these neurons from looming VPNs in different visual field regions convert localized looming threats into correctly oriented escapes. For a second looming-responsive VPN type, we demonstrate graded responses along the dorsoventral axis. We show that this synaptic gradient motif generalizes across all 20 primary VPN cell types and most often arises without VPN axon topography. Synaptic gradients may thus be a general mechanism for conveying spatial features of sensory information into directed motor outputs.


Assuntos
Comportamento Animal , Drosophila , Neurônios , Desempenho Psicomotor , Sinapses , Animais , Encéfalo/citologia , Encéfalo/fisiologia , Drosophila/anatomia & histologia , Drosophila/citologia , Drosophila/fisiologia , Neurônios/fisiologia , Campos Visuais/fisiologia , Sinapses/metabolismo , Axônios , Dendritos , Reação de Fuga
4.
Nature ; 614(7947): 270-274, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36755170

RESUMO

Photoelectrochemical (PEC) water splitting to produce hydrogen fuel was first reported 50 years ago1, yet artificial photosynthesis has not become a widespread technology. Although planar Si solar cells have become a ubiquitous electrical energy source economically competitive with fossil fuels, analogous PEC devices have not been realized, and standard Si p-type/n-type (p-n) junctions cannot be used for water splitting because the bandgap precludes the generation of the needed photovoltage. An alternative paradigm, the particle suspension reactor (PSR), forgoes the rigid design in favour of individual PEC particles suspended in solution, a potentially low-cost option compared with planar systems2,3. Here we report Si-based PSRs by synthesizing high-photovoltage multijunction Si nanowires (SiNWs) that are co-functionalized to catalytically split water. By encoding a p-type-intrinsic-n-type (p-i-n) superlattice within single SiNWs, tunable photovoltages exceeding 10 V were observed under 1 sun illumination. Spatioselective photoelectrodeposition of oxygen and hydrogen evolution co-catalysts enabled water splitting at infrared wavelengths up to approximately 1,050 nm, with the efficiency and spectral dependence of hydrogen generation dictated by the photonic characteristics of the sub-wavelength-diameter SiNWs. Although initial energy conversion efficiencies are low, multijunction SiNWs bring the photonic advantages of a tunable, mesoscale geometry and the material advantages of Si-including the small bandgap and economies of scale-to the PSR design, providing a new approach for water-splitting reactors.

5.
Nature ; 614(7946): 88-94, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36653458

RESUMO

Two-dimensional (2D) materials and their heterostructures show a promising path for next-generation electronics1-3. Nevertheless, 2D-based electronics have not been commercialized, owing mainly to three critical challenges: i) precise kinetic control of layer-by-layer 2D material growth, ii) maintaining a single domain during the growth, and iii) wafer-scale controllability of layer numbers and crystallinity. Here we introduce a deterministic, confined-growth technique that can tackle these three issues simultaneously, thus obtaining wafer-scale single-domain 2D monolayer arrays and their heterostructures on arbitrary substrates. We geometrically confine the growth of the first set of nuclei by defining a selective growth area via patterning SiO2 masks on two-inch substrates. Owing to substantial reduction of the growth duration at the micrometre-scale SiO2 trenches, we obtain wafer-scale single-domain monolayer WSe2 arrays on the arbitrary substrates by filling the trenches via short growth of the first set of nuclei, before the second set of nuclei is introduced, thus without requiring epitaxial seeding. Further growth of transition metal dichalcogenides with the same principle yields the formation of single-domain MoS2/WSe2 heterostructures. Our achievement will lay a strong foundation for 2D materials to fit into industrial settings.

6.
Mol Cell ; 81(10): 2064-2075.e8, 2021 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-33756105

RESUMO

Dysregulated mTORC1 signaling alters a wide range of cellular processes, contributing to metabolic disorders and cancer. Defining the molecular details of downstream effectors is thus critical for uncovering selective therapeutic targets. We report that mTORC1 and its downstream kinase S6K enhance eIF4A/4B-mediated translation of Wilms' tumor 1-associated protein (WTAP), an adaptor for the N6-methyladenosine (m6A) RNA methyltransferase complex. This regulation is mediated by 5' UTR of WTAP mRNA that is targeted by eIF4A/4B. Single-nucleotide-resolution m6A mapping revealed that MAX dimerization protein 2 (MXD2) mRNA contains m6A, and increased m6A modification enhances its degradation. WTAP induces cMyc-MAX association by suppressing MXD2 expression, which promotes cMyc transcriptional activity and proliferation of mTORC1-activated cancer cells. These results elucidate a mechanism whereby mTORC1 stimulates oncogenic signaling via m6A RNA modification and illuminates the WTAP-MXD2-cMyc axis as a potential therapeutic target for mTORC1-driven cancers.


Assuntos
Adenosina/análogos & derivados , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Estabilidade de RNA , Adenosina/metabolismo , Animais , Sequência de Bases , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Fatores de Iniciação em Eucariotos/metabolismo , Células HEK293 , Humanos , Masculino , Camundongos , Modelos Biológicos , Biossíntese de Proteínas , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fatores de Processamento de RNA/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas Quinases S6 Ribossômicas/metabolismo , Transdução de Sinais
7.
EMBO J ; 42(3): e111562, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36504455

RESUMO

Pandemic and endemic strains of Vibrio cholerae arise from toxigenic conversion by the CTXφ bacteriophage, a process by which CTXφ infects nontoxigenic strains of V. cholerae. CTXφ encodes the cholera toxin, an enterotoxin responsible for the watery diarrhea associated with cholera infections. Despite the critical role of CTXφ during infections, signals that affect CTXφ-driven toxigenic conversion or expression of the CTXφ-encoded cholera toxin remain poorly characterized, particularly in the context of the gut mucosa. Here, we identify mucin polymers as potent regulators of CTXφ-driven pathogenicity in V. cholerae. Our results indicate that mucin-associated O-glycans block toxigenic conversion by CTXφ and suppress the expression of CTXφ-related virulence factors, including the toxin co-regulated pilus and cholera toxin, by interfering with the TcpP/ToxR/ToxT virulence pathway. By synthesizing individual mucin glycan structures de novo, we identify the Core 2 motif as the critical structure governing this virulence attenuation. Overall, our results highlight a novel mechanism by which mucins and their associated O-glycan structures affect CTXφ-mediated evolution and pathogenicity of V. cholerae, underscoring the potential regulatory power housed within mucus.


Assuntos
Bacteriófagos , Toxina da Cólera , Mucinas , Vibrio cholerae , Virulência , Bacteriófagos/genética , Bacteriófagos/patogenicidade , Toxina da Cólera/genética , Toxina da Cólera/metabolismo , Mucinas/genética , Mucinas/metabolismo , Vibrio cholerae/genética , Vibrio cholerae/metabolismo , Virulência/genética , Virulência/fisiologia , Polissacarídeos/genética , Polissacarídeos/metabolismo
8.
Cell ; 148(3): 447-57, 2012 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-22304915

RESUMO

Although it is believed that neural activation can affect immune responses, very little is known about the neuroimmune interactions involved, especially the regulators of immune traffic across the blood-brain barrier which occurs in neuroimmune diseases such as multiple sclerosis (MS). Using a mouse model of MS, experimental autoimmune encephalomyelitis, we show that autoreactive T cells access the central nervous system via the fifth lumbar spinal cord. This location is defined by IL-6 amplifier-dependent upregulation of the chemokine CCL20 in associated dorsal blood vessels, which in turn depends on gravity-induced activation of sensory neurons by the soleus muscle in the leg. Impairing soleus muscle contraction by tail suspension is sufficient to reduce localized chemokine expression and block entry of pathogenic T cells at the fifth lumbar cord, suggesting that regional neuroimmune interactions may offer therapeutic targets for a variety of neurological diseases.


Assuntos
Barreira Hematoencefálica , Linfócitos T CD4-Positivos/citologia , Encefalomielite Autoimune Experimental/imunologia , Animais , Movimento Celular , Quimiocina CCL20/imunologia , Encefalomielite Autoimune Experimental/patologia , Gravitação , Interleucina-6/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/imunologia , Músculo Esquelético/inervação , Neuroimunomodulação , Medula Espinal/irrigação sanguínea
9.
Nature ; 578(7796): 621-626, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32051585

RESUMO

The mechanics of the cellular microenvironment continuously modulates cell functions such as growth, survival, apoptosis, differentiation and morphogenesis via cytoskeletal remodelling and actomyosin contractility1-3. Although all of these processes consume energy4,5, it is unknown whether and how cells adapt their metabolic activity to variable mechanical cues. Here we report that the transfer of human bronchial epithelial cells from stiff to soft substrates causes a downregulation of glycolysis via proteasomal degradation of the rate-limiting metabolic enzyme phosphofructokinase (PFK). PFK degradation is triggered by the disassembly of stress fibres, which releases the PFK-targeting E3 ubiquitin ligase tripartite motif (TRIM)-containing protein 21 (TRIM21). Transformed non-small-cell lung cancer cells, which maintain high glycolytic rates regardless of changing environmental mechanics, retain PFK expression by downregulating TRIM21, and by sequestering residual TRIM21 on a stress-fibre subset that is insensitive to substrate stiffness. Our data reveal a mechanism by which glycolysis responds to architectural features of the actomyosin cytoskeleton, thus coupling cell metabolism to the mechanical properties of the surrounding tissue. These processes enable normal cells to tune energy production in variable microenvironments, whereas the resistance of the cytoskeleton in response to mechanical cues enables the persistence of high glycolytic rates in cancer cells despite constant alterations of the tumour tissue.


Assuntos
Microambiente Celular , Citoesqueleto/metabolismo , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Glucose/metabolismo , Glicólise , Dureza , Actinas/metabolismo , Actomiosina/metabolismo , Animais , Brônquios/citologia , Bovinos , Diferenciação Celular , Linhagem Celular , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Fosfofrutoquinases/química , Fosfofrutoquinases/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Ribonucleoproteínas/metabolismo , Fibras de Estresse/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
10.
Annu Rev Physiol ; 84: 611-629, 2022 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-34724436

RESUMO

The use of electronic (e)-cigarettes was initially considered a beneficial solution to conventional cigarette smoking cessation. However, paradoxically, e-cigarette use is rapidly growing among nonsmokers, including youth and young adults. In 2019, this rapid growth resulted in an epidemic of hospitalizations and deaths of e-cigarette users (vapers) due to acute lung injury; this novel disease was termed e-cigarette or vaping use-associated lung injury (EVALI). Pathophysiologic mechanisms of EVALI likely involve cytotoxicity and neutrophilic inflammation caused by inhaled chemicals, but further details remain unknown. The undiscovered mechanisms of EVALI are a barrier to identifying biomarkers and developing therapeutics. Furthermore, adverse effects of e-cigarette use have been linked to chronic lung diseases and systemic effects on multiple organs. In this comprehensive review, we discuss the diverse spectrum of vaping exposures, epidemiological and clinical reports, and experimental findings to provide a better understanding of EVALI and the adverse health effects of chronic e-cigarette exposure.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Lesão Pulmonar , Pneumonia , Vaping , Adolescente , Biomarcadores , Humanos , Lesão Pulmonar/induzido quimicamente , Lesão Pulmonar/epidemiologia , Pneumonia/etiologia , Vaping/efeitos adversos , Vaping/epidemiologia , Adulto Jovem
11.
Gastroenterology ; 166(3): 503-514, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38007053

RESUMO

BACKGROUND & AIMS: Nationwide organized gastric cancer (GC) screening programs have been running for decades in South Korea and Japan. This study conducted a quasi-experimental analysis to assess the population impact of these programs on GC mortality. METHODS: We used the flexible synthetic control method (SCM) to estimate the effect of the screening programs on age-standardized GC mortality and other upper gastrointestinal (UGI) diseases (esophageal cancer and peptic ulcer) among people aged ≥40 years. World Health Organization mortality data and country-level covariates from the World Bank and the Global Burden of Diseases study were used for the analyses. We compared postintervention trends in outcome with the counterfactual trend of the synthetic control and estimated average postintervention rate ratios (RRs) with associated 95% confidence intervals (CIs). A series of sensitivity analyses were conducted. RESULTS: The preintervention fits were acceptable for the analyses of South Korea and Japan's GC mortality but poor for Japan's other UGI disease mortality. The average postintervention RRs were 0.83 (95% CI, 0.71-0.96) for GC mortality and 0.72 (95% CI, 0.57-0.90) for other UGI disease mortality in South Korea. The RR reached 0.59 by the 15th year after the initiation of nationwide screening. For Japan, the average RRs were 0.97 (95% CI, 0.88-1.07) for GC mortality and 0.93 (95% CI, 0.68-1.28) for other UGI disease mortality. Sensitivity analysis reveals the result for Japan may potentially be biased. CONCLUSIONS: South Korea's nationwide GC screening has apparent benefits, whereas the Japanese program's effectiveness is uncertain. The experiences of South Korea and Japan could serve as a reference for other countries.


Assuntos
Doenças do Esôfago , Úlcera Péptica , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/diagnóstico , Detecção Precoce de Câncer , República da Coreia/epidemiologia , Japão/epidemiologia
12.
PLoS Pathog ; 19(5): e1011415, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37216386

RESUMO

The facultative human pathogen, Vibrio cholerae, employs two-component signal transduction systems (TCS) to sense and respond to environmental signals encountered during its infection cycle. TCSs consist of a sensor histidine kinase (HK) and a response regulator (RR); the V. cholerae genome encodes 43 HKs and 49 RRs, of which 25 are predicted to be cognate pairs. Using deletion mutants of each HK gene, we analyzed the transcription of vpsL, a biofilm gene required for Vibrio polysaccharide and biofilm formation. We found that a V. cholerae TCS that had not been studied before, now termed Rvv, controls biofilm gene transcription. The Rvv TCS is part of a three-gene operon that is present in 30% of Vibrionales species. The rvv operon encodes RvvA, the HK; RvvB, the cognate RR; and RvvC, a protein of unknown function. Deletion of rvvA increased transcription of biofilm genes and altered biofilm formation, while deletion of rvvB or rvvC lead to no changes in biofilm gene transcription. The phenotypes observed in ΔrvvA depend on RvvB. Mutating RvvB to mimic constitutively active and inactive versions of the RR only impacted phenotypes in the ΔrvvA genetic background. Mutating the conserved residue required for kinase activity in RvvA did not affect phenotypes, whereas mutation of the conserved residue required for phosphatase activity mimicked the phenotype of the rvvA mutant. Furthermore, ΔrvvA displayed a significant colonization defect which was dependent on RvvB and RvvB phosphorylation state, but not on VPS production. We found that RvvA's phosphatase activity regulates biofilm gene transcription, biofilm formation, and colonization phenotypes. This is the first systematic analysis of the role of V. cholerae HKs in biofilm gene transcription and resulted in the identification of a new regulator of biofilm formation and virulence, advancing our understanding of the role TCSs play in regulating these critical cellular processes in V. cholerae.


Assuntos
Vibrio cholerae , Humanos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes , Virulência , Monoéster Fosfórico Hidrolases/metabolismo , Regulação Bacteriana da Expressão Gênica
13.
Acc Chem Res ; 57(11): 1565-1576, 2024 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-38781567

RESUMO

Intracellular cargo trafficking is a highly regulated process responsible for transporting vital cellular components to their designated destinations. This intricate journey has been a central focus of cellular biology for many years. Early investigations leaned heavily on biochemical and genetic approaches, offering valuable insight into molecular mechanisms of cellular trafficking. However, while informative, these methods lack the capacity to capture the dynamic nature of intracellular trafficking. The advent of fluorescent protein tagging techniques transformed our ability to monitor the complete lifecycle of intracellular cargos, advancing our understanding. Yet, a central question remains: How do these cargos manage to navigate through traffic challenges, such as congestion, within the crowded cellular environment? Fluorescence-based imaging, though valuable, has inherent limitations when it comes to addressing the aforementioned question. It is prone to photobleaching, making long-term live-cell imaging challenging. Furthermore, they render unlabeled cellular constituents invisible, thereby missing critical environmental information. Notably, the unlabeled majority likely exerts a significant influence on the observed behavior of labeled molecules. These considerations underscore the necessity of developing complementary label-free imaging methods to overcome the limitations of fluorescence imaging or to integrate them synergistically.In this Account, we outline how label-free interference-based imaging has the potential to revolutionize the study of intracellular traffic by offering unprecedented levels of detail. We begin with a brief introduction to our previous findings in live-cell research enabled by interferometric scattering (iSCAT) microscopy, showcasing its aptitude and adeptness in elucidating intricate nanoscale intracellular structures. As we delved deeper into our exploration, we succeeded in the label-free visualization of the entire lifespan of nanoscale protein complexes known as nascent adhesions (NAs) and the dynamic events associated with adhesions within living cells. Our continuous efforts have led to the development of Dynamic Scattering-particle Localization Interference Microscopy (DySLIM), a generalized concept of cargo-localization iSCAT (CL-iSCAT). This label-free, high-speed imaging method, armed with iSCAT detection sensitivity, empowers us to capture quantitative and biophysical insights into cargo transport, providing a realistic view of the intricate nanoscale logistics occurring within living cells. Our in vivo studies demonstrate that intracellular cargos regularly contend with substantial traffic within the crowded cellular environment. Simultaneously, they employ inherent strategies for efficient cargo transport, such as collective migration and hitchhiking, to enhance overall transport rates─intriguingly paralleling the principle and practice of urban traffic management. We also highlight the synergistic benefits of combining DySLIM with chemical-selective fluorescent methods. This Account concludes with a "Conclusions and Outlook" section, outlining promising directions for future research and developments, with a particular emphasis on the functional application of iSCAT live-cell imaging. We aim to inspire further investigation into the efficient transport strategies employed by cells to surmount transportation challenges, shedding light on their significance in cellular phenomena.


Assuntos
Imagem Óptica , Humanos , Animais , Transporte Biológico , Microscopia de Fluorescência
14.
Ann Neurol ; 95(3): 596-606, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38054838

RESUMO

OBJECTIVE: Spinal and bulbar muscular atrophy (SBMA) is characterized by slow, progressive bulbar and limb muscle weakness; however, the pattern of progression of muscle fat infiltration remains unclear. We assessed the progression of muscle involvement in 81 patients with SBMA using whole-body muscle magnetic resonance imaging (MRI), alongside clinical and laboratory findings. METHODS: This prospective study included patients with genetically confirmed SBMA who underwent whole-body muscle MRI. We analyzed muscle fat infiltration and the pattern of involved muscles using cluster analysis, visualizing the sequential progression of fat infiltration. Muscle clusters demonstrated correlation with clinical scales and laboratory findings. Additionally, linear regression analysis was performed to identify the MRI section most strongly associated with 6-minute walk test (6MWT). RESULTS: We included 81 patients with SBMA (age = 54.3 years). After categorizing the patients into 6 clusters based on the pattern of muscle fat infiltration, we observed that muscle involvement began in the posterior calf and progressed to the posterior thigh, pelvis, trunk, anterior thigh, medial thigh, anterior calf, and upper extremity muscles. These muscle clusters correlated significantly with disease duration (τ = 0.47, p < 0.001), 6MWT (τ = -0.49, p < 0.001), and serum creatinine level (τ = -0.46, p < 0.001). The whole-body MRI indicated the thigh as the section most significantly correlated with 6MWT. INTERPRETATION: We used whole-body muscle MRI to determine the sequential progression of the fat infiltration in SBMA. Our findings may enable the identification of objective and reliable imaging outcome measures in the study of the natural history or future clinical trials of SBMA. ANN NEUROL 2024;95:596-606.


Assuntos
Atrofia Bulboespinal Ligada ao X , Atrofia Muscular Espinal , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Atrofia Bulboespinal Ligada ao X/diagnóstico por imagem , Atrofia Bulboespinal Ligada ao X/patologia , Atrofia Muscular/patologia , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/patologia , Atrofia Muscular Espinal/diagnóstico por imagem , Atrofia Muscular Espinal/patologia , Imageamento por Ressonância Magnética
15.
Chem Soc Rev ; 53(9): 4674-4706, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38529583

RESUMO

High power conversion efficiency (PCE) and long-term stability are essential prerequisites for the commercialization of polymer solar cells (PSCs). Small-molecule acceptors (SMAs) are core materials that have led to recent, rapid increases in the PCEs of the PSCs. However, a critical limitation of the resulting PSCs is their poor long-term stability. Blend morphology degradation from rapid diffusion of SMAs with low glass transition temperatures (Tgs) is considered the main cause of the poor long-term stability of the PSCs. The recent emergence of oligomerized SMAs (OSMAs), composed of two or more repeating SMA units (i.e., dimerized and trimerized SMAs), has shown great promise in overcoming these challenges. This innovation in material design has enabled OSMA-based PSCs to reach impressive PCEs near 19% and exceptional long-term stability. In this review, we summarize the evolution of OSMAs, including their research background and recent progress in molecular design. In particular, we discuss the mechanisms for high PCE and stability of OSMA-based PSCs and suggest useful design guidelines for high-performance OSMAs. Furthermore, we reflect on the existing hurdles and future directions for OSMA materials towards achieving commercially viable PSCs with high PCEs and operational stabilities.

16.
Chem Soc Rev ; 53(10): 5190-5226, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38586901

RESUMO

Etching technology - one of the representative modern semiconductor device makers - serves as a broad descriptor for the process of removing material from the surfaces of various materials, whether partially or entirely. Meanwhile, thinning technology represents a novel and highly specialized approach within the realm of etching technology. It indicates the importance of achieving an exceptionally sophisticated and precise removal of material, layer-by-layer, at the nanoscale. Notably, thinning technology has gained substantial momentum, particularly in top-down strategies aimed at pushing the frontiers of nano-worlds. This rapid development in thinning technology has generated substantial interest among researchers from diverse backgrounds, including those in the fields of chemistry, physics, and engineering. Precisely and expertly controlling the layer numbers of 2D materials through the thinning procedure has been considered as a crucial step. This is because the thinning processes lead to variations in the electrical and optical characteristics. In this comprehensive review, the strategies for top-down thinning of representative 2D materials (e.g., graphene, black phosphorus, MoS2, h-BN, WS2, MoSe2, and WSe2) based on conventional plasma-assisted thinning, integrated cyclic plasma-assisted thinning, laser-assisted thinning, metal-assisted splitting, and layer-resolved splitting are covered in detail, along with their mechanisms and benefits. Additionally, this review further explores the latest advancements in terms of the potential advantages of semiconductor devices achieved by top-down 2D material thinning procedures.

17.
Nano Lett ; 24(8): 2574-2580, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38349338

RESUMO

The highly programmable and responsive molecular recognition properties of DNA provide unparalleled opportunities for fabricating dynamic nanostructures capable of structural transformation in response to various external stimuli. However, they typically operate in tightly controlled environments because certain conditions (ionic strength, pH, temperature, etc.) must be met for DNA duplex formation. In this study, we adopted site-specific enzymatic ligation and DNA-based layer-by-layer thin film fabrication to build shape-morphing DNA-linked nanoparticle films operational in a broad range of environments. The ligated films remained intact in unusual conditions such as pure water and high temperature causing dissociation of DNA duplexes and showed predictable and reversible shape morphing in response to various environmental changes and DNA exchange reactions. Furthermore, domain-selective ligation combined with photoinduced interlayer mixing allowed for the fabrication of unusual edge-sealed double-layered films through midlayer etching, which is difficult to realize by other methods.


Assuntos
Nanopartículas , Nanoestruturas , DNA/química , Água , Temperatura
18.
Nano Lett ; 24(4): 1324-1331, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38230977

RESUMO

Oxide semiconductors (OS) are attractive materials for memory and logic device applications owing to their low off-current, high field effect mobility, and superior large-area uniformity. Recently, successful research has reported the high field-effect mobility (µFE) of crystalline OS channel transistors (above 50 cm2 V-1 s-1). However, the memory and logic device application presents challenges in mobility and stability trade-offs. Here, we propose a method for achieving high-mobility and high-stability by lowering the grain boundary effect. A DBADMIn precursor was synthesized to deposit highly c-axis-aligned C(222) crystalline 3 nm thick In2O3 films. In this study, the 250 °C deposited 3 nm thick In2O3 channel transistor exhibited high µFE of 41.12 cm2 V-1 s-1, Vth of -0.50 V, and SS of 150 mV decade-1 with superior stability of 0.16 V positive shift during PBTS at 100 °C, 3 MV cm-1 stress conditions for 3 h.

19.
Gut ; 73(3): 407-441, 2024 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-38383142

RESUMO

At the end of the last century, a far-sighted 'working party' held in Sydney, Australia addressed the clinicopathological issues related to gastric inflammatory diseases. A few years later, an international conference held in Houston, Texas, USA critically updated the seminal Sydney classification. In line with these initiatives, Kyoto Global Consensus Report, flanked by the Maastricht-Florence conferences, added new clinical evidence to the gastritis clinicopathological puzzle.The most relevant topics related to the gastric inflammatory diseases have been addressed by the Real-world Gastritis Initiative (RE.GA.IN.), from disease definitions to the clinical diagnosis and prognosis. This paper reports the conclusions of the RE.GA.IN. consensus process, which culminated in Venice in November 2022 after more than 8 months of intense global scientific deliberations. A forum of gastritis scholars from five continents participated in the multidisciplinary RE.GA.IN. consensus. After lively debates on the most controversial aspects of the gastritis spectrum, the RE.GA.IN. Faculty amalgamated complementary knowledge to distil patient-centred, evidence-based statements to assist health professionals in their real-world clinical practice. The sections of this report focus on: the epidemiology of gastritis; Helicobacter pylori as dominant aetiology of environmental gastritis and as the most important determinant of the gastric oncogenetic field; the evolving knowledge on gastric autoimmunity; the clinicopathological relevance of gastric microbiota; the new diagnostic horizons of endoscopy; and the clinical priority of histologically reporting gastritis in terms of staging. The ultimate goal of RE.GA.IN. was and remains the promotion of further improvement in the clinical management of patients with gastritis.


Assuntos
Gastrite , Infecções por Helicobacter , Helicobacter pylori , Neoplasias Gástricas , Humanos , Infecções por Helicobacter/complicações , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/patologia , Gastrite/diagnóstico , Gastrite/epidemiologia , Gastrite/patologia , Endoscopia , Neoplasias Gástricas/patologia , Mucosa Gástrica/patologia
20.
Trends Biochem Sci ; 45(5): 367-369, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32311329

RESUMO

Using cryo-electron microscopy and molecular characterization, David Sabatini and colleagues provide crucial new insights that validate and expand their model of how amino acids are sensed and signal at the lysosome to activate mechanistic target of rapamycin complex 1 (mTORC1) and cell growth-regulating processes. This work also reveals new therapeutic opportunities for mTORC1-driven diseases.


Assuntos
Microscopia Crioeletrônica , Transdução de Sinais , Aminoácidos , Lisossomos/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA