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1.
Nature ; 626(7999): 500-504, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38356071

RESUMEN

Magnetars are neutron stars with extremely high magnetic fields (≳1014 gauss) that exhibit various X-ray phenomena such as sporadic subsecond bursts, long-term persistent flux enhancements and variable rotation-period derivative1,2. In 2020, a fast radio burst (FRB), akin to cosmological millisecond-duration radio bursts, was detected from the Galactic magnetar SGR 1935+2154 (refs. 3-5), confirming the long-suspected association between some FRBs and magnetars. However, the mechanism for FRB generation in magnetars remains unclear. Here we report the X-ray observation of two glitches in SGR 1935+2154 within a time interval of approximately nine hours, bracketing an FRB that occurred on 14 October 20226,7. Each glitch involved a significant increase in the magnetar's spin frequency, being among the largest abrupt changes in neutron-star rotation8-10 observed so far. Between the glitches, the magnetar exhibited a rapid spin-down phase, accompanied by an increase and subsequent decline in its persistent X-ray emission and burst rate. We postulate that a strong, ephemeral, magnetospheric wind11 provides the torque that rapidly slows the star's rotation. The trigger for the first glitch couples the star's crust to its magnetosphere, enhances the various X-ray signals and spawns the wind that alters magnetospheric conditions that might produce the FRB.

2.
Immunity ; 53(5): 952-970.e11, 2020 11 17.
Artículo en Inglés | MEDLINE | ID: mdl-33098766

RESUMEN

Precise targeting of activation-induced cytidine deaminase (AID) to immunoglobulin (Ig) loci promotes antibody class switch recombination (CSR) and somatic hypermutation (SHM), whereas AID targeting of non-Ig loci can generate oncogenic DNA lesions. Here, we examined the contribution of G-quadruplex (G4) nucleic acid structures to AID targeting in vivo. Mice bearing a mutation in Aicda (AIDG133V) that disrupts AID-G4 binding modeled the pathology of hyper-IgM syndrome patients with an orthologous mutation, lacked CSR and SHM, and had broad defects in genome-wide AIDG133V chromatin localization. Genome-wide analyses also revealed that wild-type AID localized to MHCII genes, and AID expression correlated with decreased MHCII expression in germinal center B cells and diffuse large B cell lymphoma. Our findings indicate a crucial role for G4 binding in AID targeting and suggest that AID activity may extend beyond Ig loci to regulate the expression of genes relevant to the physiology and pathology of activated B cells.


Asunto(s)
Cromatina/genética , Cromatina/metabolismo , Citidina Desaminasa/genética , Citidina Desaminasa/metabolismo , G-Cuádruplex , Síndrome de Inmunodeficiencia con Hiper-IgM/etiología , Síndrome de Inmunodeficiencia con Hiper-IgM/metabolismo , Mutación , Animales , Linfocitos B/inmunología , Linfocitos B/metabolismo , Biología Computacional/métodos , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Activación Enzimática , Técnica del Anticuerpo Fluorescente , Perfilación de la Expresión Génica , Estudio de Asociación del Genoma Completo , Centro Germinal/inmunología , Centro Germinal/metabolismo , Antígenos HLA/genética , Antígenos HLA/inmunología , Humanos , Síndrome de Inmunodeficiencia con Hiper-IgM/diagnóstico , Cambio de Clase de Inmunoglobulina/genética , Cambio de Clase de Inmunoglobulina/inmunología , Inmunofenotipificación , Activación de Linfocitos/genética , Linfoma de Células B Grandes Difuso/etiología , Linfoma de Células B Grandes Difuso/metabolismo , Linfoma de Células B Grandes Difuso/patología , Ratones , Ratones Transgénicos
3.
Nature ; 588(7837): 337-343, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33239788

RESUMEN

The zebrafish (Danio rerio) has been widely used in the study of human disease and development, and about 70% of the protein-coding genes are conserved between the two species1. However, studies in zebrafish remain constrained by the sparse annotation of functional control elements in the zebrafish genome. Here we performed RNA sequencing, assay for transposase-accessible chromatin using sequencing (ATAC-seq), chromatin immunoprecipitation with sequencing, whole-genome bisulfite sequencing, and chromosome conformation capture (Hi-C) experiments in up to eleven adult and two embryonic tissues to generate a comprehensive map of transcriptomes, cis-regulatory elements, heterochromatin, methylomes and 3D genome organization in the zebrafish Tübingen reference strain. A comparison of zebrafish, human and mouse regulatory elements enabled the identification of both evolutionarily conserved and species-specific regulatory sequences and networks. We observed enrichment of evolutionary breakpoints at topologically associating domain boundaries, which were correlated with strong histone H3 lysine 4 trimethylation (H3K4me3) and CCCTC-binding factor (CTCF) signals. We performed single-cell ATAC-seq in zebrafish brain, which delineated 25 different clusters of cell types. By combining long-read DNA sequencing and Hi-C, we assembled the sex-determining chromosome 4 de novo. Overall, our work provides an additional epigenomic anchor for the functional annotation of vertebrate genomes and the study of evolutionarily conserved elements of 3D genome organization.


Asunto(s)
Genoma/genética , Imagenología Tridimensional , Imagen Molecular , Secuencias Reguladoras de Ácidos Nucleicos/genética , Pez Cebra/genética , Animales , Encéfalo/metabolismo , Secuencia Conservada/genética , Metilación de ADN , Elementos de Facilitación Genéticos/genética , Epigénesis Genética , Evolución Molecular , Femenino , Perfilación de la Expresión Génica , Redes Reguladoras de Genes/genética , Heterocromatina/química , Heterocromatina/genética , Heterocromatina/metabolismo , Humanos , Masculino , Ratones , Especificidad de Órganos , Regiones Promotoras Genéticas/genética , Análisis de la Célula Individual , Especificidad de la Especie
4.
Nat Methods ; 19(8): 995-1003, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35879608

RESUMEN

Explaining the diversity and complexity of protein localization is essential to fully understand cellular architecture. Here we present cytoself, a deep-learning approach for fully self-supervised protein localization profiling and clustering. Cytoself leverages a self-supervised training scheme that does not require preexisting knowledge, categories or annotations. Training cytoself on images of 1,311 endogenously labeled proteins from the OpenCell database reveals a highly resolved protein localization atlas that recapitulates major scales of cellular organization, from coarse classes, such as nuclear and cytoplasmic, to the subtle localization signatures of individual protein complexes. We quantitatively validate cytoself's ability to cluster proteins into organelles and protein complexes, showing that cytoself outperforms previous self-supervised approaches. Moreover, to better understand the inner workings of our model, we dissect the emergent features from which our clustering is derived, interpret them in the context of the fluorescence images, and analyze the performance contributions of each component of our approach.


Asunto(s)
Aprendizaje Profundo , Análisis por Conglomerados , Orgánulos/metabolismo , Transporte de Proteínas , Proteínas/metabolismo
5.
Nature ; 575(7781): 147-150, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31695211

RESUMEN

Elastic electron-proton scattering (e-p) and the spectroscopy of hydrogen atoms are the two methods traditionally used to determine the proton charge radius, rp. In 2010, a new method using muonic hydrogen atoms1 found a substantial discrepancy compared with previous results2, which became known as the 'proton radius puzzle'. Despite experimental and theoretical efforts, the puzzle remains unresolved. In fact, there is a discrepancy between the two most recent spectroscopic measurements conducted on ordinary hydrogen3,4. Here we report on the proton charge radius experiment at Jefferson Laboratory (PRad), a high-precision e-p experiment that was established after the discrepancy was identified. We used a magnetic-spectrometer-free method along with a windowless hydrogen gas target, which overcame several limitations of previous e-p experiments and enabled measurements at very small forward-scattering angles. Our result, rp = 0.831 ± 0.007stat ± 0.012syst femtometres, is smaller than the most recent high-precision e-p measurement5 and 2.7 standard deviations smaller than the average of all e-p experimental results6. The smaller rp we have now measured supports the value found by two previous muonic hydrogen experiments1,7. In addition, our finding agrees with the revised value (announced in 2019) for the Rydberg constant8-one of the most accurately evaluated fundamental constants in physics.

6.
Proc Natl Acad Sci U S A ; 119(43): e2212343119, 2022 10 25.
Artículo en Inglés | MEDLINE | ID: mdl-36227945

RESUMEN

The natural black-brown pigment eumelanin protects humans from high-energy UV photons by absorbing and rapidly dissipating their energy before proteins and DNA are damaged. The extremely weak fluorescence of eumelanin points toward nonradiative relaxation on the timescale of picoseconds or shorter. However, the extreme chemical and physical complexity of eumelanin masks its photoprotection mechanism. We sought to determine the electronic and structural relaxation pathways in eumelanin using three complementary ultrafast optical spectroscopy methods: fluorescence, transient absorption, and stimulated Raman spectroscopies. We show that photoexcitation of chromophores across the UV-visible spectrum rapidly generates a distribution of visible excitation energies via ultrafast internal conversion among neighboring coupled chromophores, and then all these excitations relax on a timescale of ∼4 ps without transferring their energy to other chromophores. Moreover, these picosecond dynamics are shared by the monomeric building block, 5,6-dihydroxyindole-2-carboxylic acid. Through a series of solvent and pH-dependent measurements complemented by quantum chemical modeling, we show that these ultrafast dynamics are consistent with the partial excited-state proton transfer from the catechol hydroxy groups to the solvent. The use of this multispectroscopic approach allows the minimal functional unit in eumelanin and the role of exciton coupling and excited-state proton transfer to be determined, and ultimately reveals the mechanism of photoprotection in eumelanin. This knowledge has potential for use in the design of new soft optical components and organic sunscreens.


Asunto(s)
Protones , Protectores Solares , Catecoles , Humanos , Melaninas , Solventes
7.
J Am Soc Nephrol ; 35(3): 299-310, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38254260

RESUMEN

SIGNIFICANCE STATEMENT: Black adults in the United States have 2-4 times higher incidence of kidney failure than White adults. Yet, the reasons underlying this disparity remain poorly understood. Among 547,188 US veterans with new-onset CKD, according to a new race-free GFR equation, Black veterans had a 2.5-fold higher cumulative incidence of kidney failure, compared with White veterans, in any follow-up period from CKD onset. This disparity resulted from a combination of higher hazards of progression to kidney failure and lower hazards of competing-risk death in Black veterans. Both, in turn, were largely explained by the younger age at CKD onset in Black veterans, underscoring an urgent need to prevent early onset and slow progression of CKD in younger Black adults. BACKGROUND: The Black adult population is well known to have higher incidence of kidney failure than their White counterpart in the United States, but the reasons underlying this disparity are unclear. We assessed the racial differences in kidney failure and death from onset of CKD on the basis of the race-free 2021 CKD Epidemiology Collaboration equation and examined the extent to which these differences could be explained by factors at the time of CKD onset. METHODS: We analyzed a national cohort consisting of 547,188 US veterans (103,821 non-Hispanic Black and 443,367 non-Hispanic White), aged 18-85 years, with new-onset CKD between 2005 and 2016 who were followed through 10 years or May 2018 for incident kidney failure with replacement therapy (KFRT) and pre-KFRT death. RESULTS: At CKD onset, Black veterans were, on average, 7.8 years younger than White veterans. In any time period from CKD onset, the cumulative incidence of KFRT was 2.5-fold higher for Black versus White veterans. Meanwhile, Black veterans had persistently >2-fold higher hazards of KFRT throughout follow-up (overall hazard ratio [95% confidence interval], 2.38 [2.31 to 2.45]) and conversely had 17%-48% decreased hazards of pre-KFRT death. These differences were reduced after accounting for the racial difference in age at CKD onset. CONCLUSIONS: The 2.5-fold higher cumulative incidence of kidney failure in Black adults resulted from a combination of higher hazards of progression to kidney failure and lower hazards of the competing risk of death, both of which can be largely explained by the younger age at CKD onset in Black compared with White adults.


Asunto(s)
Insuficiencia Renal Crónica , Insuficiencia Renal , Adulto , Humanos , Estados Unidos/epidemiología , Incidencia , Etnicidad , Insuficiencia Renal Crónica/epidemiología , Insuficiencia Renal Crónica/terapia , Blanco
8.
Biophys J ; 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38961621

RESUMEN

The adhesin FimH is expressed by commensal Escherichia coli and is implicated in urinary tract infections, where it mediates adhesion to mannosylated glycoproteins on urinary and intestinal epithelial cells in the presence of a high shear fluid environment. The FimH-mannose bond exhibits catch behavior in which bond lifetime increases with force, because tensile force induces a transition in FimH from a compact native to an elongated activated conformation with a higher affinity to mannose. However, the lifetime of the activated state of FimH has not been measured under force. Here we apply multiplexed magnetic tweezers to apply a pre-load force to activate FimH bonds with yeast mannan, then measure the lifetime of these activated bonds under a wide range of forces above and below the preload force. A higher fraction of FimH-mannan bonds were activated above than below a critical preload force, confirming the FimH catch bond behavior. Once activated, FimH detached from mannose with multi-state kinetics, suggesting the existence of two bound states with a twenty-fold difference in dissociation rates. The average lifetime of activated FimH-mannose bonds was 1000 to 10,000 seconds at forces of 30 to 70 pN. Structural explanations of the two bound states and the high force resistance provide insights into structural mechanisms for long-lived, force resistant biomolecular interactions.

9.
Antimicrob Agents Chemother ; 68(1): e0095323, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38047645

RESUMEN

Molnupiravir, an oral prodrug of N-hydroxycytidine (NHC), previously demonstrated broad in vitro antiviral activity against multiple RNA viruses and has shown a high barrier to the development of resistance. Here, we present the antiviral activity of NHC against recent SARS-CoV-2 variants and the results of resistance selection studies to better understand the potential for viral resistance to NHC. NHC activity against SARS-CoV-2 variants omicron (BA.1, BA.1.1, BA.2, BA.4, BA.4.6, BA.5, BQ.1.1, XBB.1, and XBB.1.5), alpha (B.1.1.7), beta (B.1.351), gamma (P.1), delta (B.1.617.2), lambda (C.37), and mu (B.1.621) was evaluated in Vero E6 cells using cytopathic effect assays. Resistance selection studies were performed by passaging SARS-CoV-2 (WA1) in the presence of NHC or a 3C-like protease inhibitor (MRK-A) in Vero E6 cells. Supernatants from cultures exhibiting a cytopathic effect score of ≥2 were re-passaged, and IC50 values were estimated. Whole-genome deep sequencing was performed on viral RNA isolated at each passage. NHC demonstrated similar potency against all SARS-CoV-2 variants evaluated. No evidence of SARS-CoV-2 phenotypic or genotypic resistance to NHC was observed following 30 passages. A random pattern of nucleotide changes was observed in NHC cultures, consistent with the drug's mechanism of action. In contrast, resistance was readily selected in all three MRK-A control cultures with the selection of a T21I substitution in the 3C-like protease. In conclusion, molnupiravir maintains antiviral activity across all major SARS-CoV-2 variants. Furthermore, no evidence of viral resistance to NHC was observed, supporting previous reports that NHC has a high barrier to developing resistance.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Antivirales/farmacología
10.
Am J Physiol Regul Integr Comp Physiol ; 326(2): R176-R183, 2024 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-38047317

RESUMEN

Down syndrome (DS) is associated with congenital heart defects at birth, but cardiac function has not been assessed at older ages. We used the Ts65Dn mouse, a model of DS, to quantify heart structure and function with echocardiography in 18-mo male Ts65Dn and wild-type (WT) mice. Heart weight, nicotinamide adenine dinucleotide (NAD) signaling, and mitochondrial (citrate synthase) activity were investigated, as these pathways may be implicated in the cardiac pathology of DS. The left ventricle was smaller in Ts65Dn versus WT, as well as the anterior wall thickness of the left ventricle during both diastole (LVAW_d; mm) and systole (LVAW_s; mm) as assessed by echocardiography. Other functional metrics were similar between groups including left ventricular area end systole (mm2), left ventricular area end diastole (mm2), left ventricular diameter end systole (mm), left ventricular diameter end diastole (mm), isovolumetric relaxation time (ms), mitral valve atrial peak velocity (mm/s), mitral valve early peak velocity (mm/s), ratio of atrial and early peak velocities (E/A), heart rate (beats/min), ejection fraction (%), and fractional shortening (%). Nicotinamide phosphoribosyltransferase (NAMPT) protein expression, NAD concentration, and tissue weight were lower in the left ventricle of Ts65Dn versus WT mice. Sirtuin 3 (SIRT3) protein expression and citrate synthase activity were not different between groups. Although cardiac function was generally preserved in male Ts65Dn, the altered heart size and bioenergetic disturbances may contribute to differences in aging for DS.


Asunto(s)
NAD , Función Ventricular Izquierda , Masculino , Ratones , Animales , Función Ventricular Izquierda/fisiología , Citrato (si)-Sintasa , Diástole/fisiología , Ecocardiografía
11.
Am J Nephrol ; 55(1): 115-126, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37725913

RESUMEN

INTRODUCTION: While Asian and Native Hawaiian and other Pacific Islander (NHOPI) patients have a high prevalence of kidney disease risk factors, there are sparse data examining their end-stage kidney disease (ESKD) outcomes. As Hawaii has high representation of Asian and NHOPI individuals, we compared their ESKD outcomes based on residence in the mainland USA versus Hawaii/Pacific Islands (PIs). MATERIALS AND METHODS: Using United States Renal Data System data, we examined the impact of geographic residence in the mainland versus Hawaii/PIs on race-mortality associations among incident ESKD patients transitioning to dialysis over January 1, 2000-December 31, 2016 using Cox regression. We examined likelihood of post-dialysis kidney transplantation using Cox models and cumulative incidence curves. RESULTS: Compared with White patients in the mainland, Asian and NHOPI patients in the mainland had lower mortality: adjusted HRs (95% CIs) 0.67 (0.66-0.67) and 0.72 (0.70-0.73), respectively. When examining Asian and NHOPI patients in Hawaii/PIs, survival benefit was attenuated in Asian and diminished to the null in NHOPI patients (ref: mainland White patients). Cumulative incidence curves comparing Asian, NHOPI, and White patients showed Asian and NHOPI patients in the mainland had the highest likelihood of transplantation, whereas NHOPI and Asian patients in Hawaii/PIs had the lowest likelihood. CONCLUSION: In the mainland, Asian and NHOPI patients had lower mortality versus White patients, whereas in Hawaii/PIs, this survival benefit was diminished in Asian and mitigated in NHOPI patients. NHOPI and Asian patients in Hawaii/PIs had less transplantation versus those in the mainland. Further research is needed to uncover factors contributing to differential ESKD outcomes among Asian and NHOPI patients across geographic residence.


Asunto(s)
Asiático , Disparidades en Atención de Salud , Fallo Renal Crónico , Nativos de Hawái y Otras Islas del Pacífico , Humanos , Fallo Renal Crónico/mortalidad , Fallo Renal Crónico/terapia , Estados Unidos/epidemiología , Grupos Raciales
12.
Inorg Chem ; 63(11): 4947-4956, 2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38437618

RESUMEN

A series of photosensitizers comprised of both an inorganic and an organic chromophore are investigated in a joint synthetic, spectroscopic, and theoretical study. This bichromophoric design strategy provides a means by which to significantly increase the excited state lifetime by isolating the excited state away from the metal center following intersystem crossing. A variable bridging group is incorporated between the donor and acceptor units of the organic chromophore, and its influence on the excited state properties is explored. The Franck-Condon (FC) photophysics and subsequent excited state relaxation pathways are investigated with a suite of steady-state and time-resolved spectroscopic techniques in combination with scalar-relativistic quantum chemical calculations. It is demonstrated that the presence of an electronically conducting bridge that facilitates donor-acceptor communication is vital to generate long-lived (32 to 45 µs), charge-separated states with organic character. In contrast, when an insulating 1,2,3-triazole bridge is used, the excited state properties are dominated by the inorganic chromophore, with a notably shorter lifetime of 60 ns. This method of extending the lifetime of a molecular photosensitizer is, therefore, of interest for a range of molecular electronic devices and photophysical applications.

13.
Public Health Nutr ; 27(1): e74, 2024 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-38361460

RESUMEN

OBJECTIVE: The primary objective of this study was to determine whether Healthy Eating Index (HEI) and Alternative Healthy Eating Index (AHEI) scores were associated with incident metabolic syndrome. DESIGN: This study is a secondary analysis of data from the Jackson Heart Study. HEI and AHEI scores were divided into quintiles and Cox proportional hazards regression models were analysed for 1864 African American adults free from metabolic syndrome at Exam 1 to examine the incidence of metabolic syndrome by quintile of dietary quality score. SETTING: Hinds, Madison and Rankin counties, Mississippi, USA. PARTICIPANTS: African American adults, ages 21-94 years, 60·9 % female. RESULTS: Over a mean follow-up time of 6·7 years, we observed 932 incident cases of metabolic syndrome. After adjusting for multiple covariates, a higher HEI score at Exam 1 was not associated with the risk of incident metabolic syndrome, except when looking at the trend analysis for the subgroup of adults with two metabolic syndrome components at Exam 1 (P-trend = 0·03). A higher AHEI score at Exam 1 was associated with the risk of incident metabolic syndrome (hazard ratio for those in the highest quintile compared to the lowest: 0·80 (95 % CI: 0·65, 0·99), P-trend = 0·03). CONCLUSION: These findings suggest that a dietary pattern that scores higher on the AHEI may help reduce the risk of metabolic syndrome, even for adults who already have two of the minimum of three components required for a diagnosis of metabolic syndrome.


Asunto(s)
Dieta Saludable , Síndrome Metabólico , Adulto , Femenino , Humanos , Masculino , Negro o Afroamericano , Dieta , Estudios Longitudinales , Síndrome Metabólico/epidemiología , Factores de Riesgo , Adulto Joven , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años
14.
Ann Intern Med ; 176(9): 1200-1208, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37579311

RESUMEN

BACKGROUND: Cardiovascular disease (CVD) mortality is persistently higher in the Black population than in other racial and ethnic groups in the United States. OBJECTIVE: To examine the degree to which social, behavioral, and metabolic risk factors are associated with CVD mortality and the extent to which racial differences in CVD mortality persist after these factors are accounted for. DESIGN: Prospective cohort study. SETTING: NHANES (National Health and Nutrition Examination Survey) 1999 to 2018. PARTICIPANTS: A nationally representative sample of 50 808 persons aged 20 years or older. MEASUREMENTS: Data on social, behavioral, and metabolic factors were collected in each NHANES survey using standard methods. Deaths from CVD were ascertained from linkage to the National Death Index with follow-up through 2019. RESULTS: Over an average of 9.4 years of follow-up, 2589 CVD deaths were confirmed. The age- and sex-standardized rates of CVD mortality were 484.7 deaths per 100 000 person-years in Black participants, 384.5 deaths per 100 000 person-years in White participants, 292.4 deaths per 100 000 person-years in Hispanic participants, and 255.1 deaths per 100 000 person-years in other race groups. In a multiple Cox regression analysis adjusted for all measured risk factors simultaneously, several social (unemployment, low family income, food insecurity, lack of home ownership, and unpartnered status), behavioral (current smoking, lack of leisure-time physical activity, and sleep <6 or >8 h/d), and metabolic (obesity, hypertension, and diabetes) risk factors were associated with a significantly higher risk for CVD death. After adjustment for these metabolic, behavioral, and social risk factors separately, hazard ratios of CVD mortality for Black compared with White participants were attenuated from 1.54 (95% CI, 1.34 to 1.77) to 1.34 (CI, 1.16 to 1.55), 1.31 (CI, 1.15 to 1.50), and 1.04 (CI, 0.90 to 1.21), respectively. LIMITATION: Causal contributions of social, behavioral, and metabolic risk factors to racial and ethnic disparities in CVD mortality could not be established. CONCLUSION: The Black-White difference in CVD mortality diminished after adjustment for behavioral and metabolic risk factors and completely dissipated with adjustment for social determinants of health in the U.S. population. PRIMARY FUNDING SOURCE: National Institutes of Health.


Asunto(s)
Enfermedades Cardiovasculares , Adulto , Humanos , Estados Unidos/epidemiología , Encuestas Nutricionales , Estudios Prospectivos , Factores de Riesgo , Grupos Raciales
15.
BMC Med Educ ; 24(1): 292, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38491363

RESUMEN

BACKGROUND: Narrative medicine demonstrated positive impact on empathy in medicine and nursing students. However, this pedagogical approach had not been evaluated in pharmacy education. This study sought to apply and evaluate the narrative medicine approach in extending empathy in Asian undergraduate pharmacy students. METHODS: Narrative medicine was applied through workshops which used narratives of people with different experiences and perspectives. First-year undergraduate pharmacy students who volunteered and attended these workshops formed the intervention group (N = 31) and the remaining first-year cohort formed the control group (N = 112). A sequential explanatory mixed methods approach was adopted in which quantitative methods were first used to measure impact on pharmacy students' empathy using the Jefferson Scale of Empathy- Health Professions Student (JSE-HPS), and qualitative methods (i.e. group interviews) were then used to assess pharmacy students' emotional responses to narratives, and the perspectives of pharmacy students and faculty of this pedagogical approach. RESULTS: There was no difference in JSE-HPS scores between intervention and control groups across baseline (i.e. upon matriculation), pre-intervention, and post-intervention timepoints. Pharmacy students in the intervention group had lower scores in Factor 3 ("Standing in People's Shoes") following the intervention. Five themes, guided by internal and external factors in cognition, emerged from the Group Interviews: (1) incongruence between students' motivation and faculty's perception, (2) learning context, (3) academic context, (4) cognitive system, and (5) affective system. Themes 1, 4 and 5 referred to internal factors such as students' motivation, perceived learnings, and feelings. Themes 2 and 3 referred to external factors including workshop materials, activities, content, and facilitation. CONCLUSION: This study is the first to demonstrate that pharmacy students engaged with the narrative medicine approach as narratives elicited emotional responses, exposed them to diverse perspectives, and deepened their appreciation of the importance of empathy and complexities of understanding patients' perspectives. Scaffolded educational interventions using narratives and real-life patient encounters, alongside longitudinal measurements of empathy, are necessary to bring about meaningful and sustained improvements in empathy.


Asunto(s)
Educación en Farmacia , Medicina Narrativa , Estudiantes de Medicina , Humanos , Singapur , Estudiantes de Medicina/psicología , Empatía , Personal de Salud
16.
Nano Lett ; 23(10): 4136-4141, 2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37162008

RESUMEN

Due to its exceptional electronic and thermal properties, graphene is a key material for bolometry, calorimetry, and photon detection. However, despite graphene's relatively simple electronic structure, the physical processes responsible for the heat transport from the electrons to the lattice are experimentally still elusive. Here, we measure the thermal response of low-disorder graphene encapsulated in hexagonal boron nitride by integrating it within a multiterminal superconducting microwave resonator. The device geometry allows us to simultaneously apply Joule heat power to the graphene flake while performing calibrated readout of the electron temperature. We probe the thermalization rates of both electrons and holes with high precision and observe a thermalization scaling exponent not consistent with cooling through the graphene bulk and argue that instead it can be attributed to processes at the graphene-aluminum interface. Our technique provides new insights into the thermalization pathways essential for the next-generation graphene thermal detectors.

17.
Lancet Oncol ; 24(2): 175-186, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36681089

RESUMEN

BACKGROUND: Anaplastic thyroid cancer is a rare and aggressive cancer with no standard radiotherapy-based local treatment. Based on data suggesting synergy between pazopanib and paclitaxel in anaplastic thyroid cancer, NRG Oncology did a double-blind, placebo-controlled, randomised phase 2 clinical trial comparing concurrent paclitaxel and intensity-modulated radiotherapy (IMRT) with the addition of pazopanib or placebo with the aim of improving overall survival in this patient population. METHODS: Eligible patients were aged 18 years or older with a pathological diagnosis of anaplastic thyroid cancer, any TNM stage, Zubrod performance status of 0-2, no recent haemoptysis or bleeding, and no brain metastases. Patients were enrolled from 34 centres in the USA. Initially, a run-in was done to establish safety. In the randomised phase 2 trial, patients in the experimental group (pazopanib) received 2-3 weeks of weekly paclitaxel (80 mg/m2) intravenously and daily pazopanib suspension 400 mg orally followed by concurrent weekly paclitaxel (50 mg/m2), daily pazopanib (300 mg), and IMRT 66 Gy given in 33 daily fractions (2 Gy fractions). In the control group (placebo), pazopanib was replaced by matching placebo. Patients were randomly assigned (1:1) to the two treatment groups by permuted block randomisation by NRG Oncology with stratification by metastatic disease. All investigators, patients, and funders of the study were masked to group allocation. The primary endpoint was overall survival in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of study treatment. This trial is registered with Clinicaltrials.gov, NCT01236547, and is complete. FINDINGS: The safety run-showed the final dosing regimen to be safe based on two out of nine participants having adverse events of predefined concern. Between June 23, 2014, and Dec 30, 2016, 89 patients were enrolled to the phase 2 trial, of whom 71 were eligible (36 in the pazopanib group and 35 in the placebo group; 34 [48%] males and 37 [52%] females). At the final analysis (data cutoff March 9, 2020), with a median follow-up of 2·9 years (IQR 0·002-4·0), 61 patients had died. Overall survival was not significantly improved with pazopanib versus placebo, with a median overall survival of 5·7 months (95% CI 4·0-12·8) in the pazopanib group versus 7·3 months (4·3-10·6) in the placebo group (hazard ratio 0·86, 95% CI 0·52-1·43; one-sided log-rank p=0·28). 1-year overall survival was 37·1% (95% CI 21·1-53·2) in the pazopanib group and 29·0% (13·2-44·8) in the placebo group. The incidence of grade 3-5 adverse events did not differ significantly between the treatment groups (pazopanib 88·9% [32 of 36 patients] and placebo 85·3% [29 of 34 patients]; p=0·73). The most common clinically significant grade 3-4 adverse events in the 70 eligible treated patients (36 in the pazopanib group and 34 in the placebo group) were dysphagia (13 [36%] vs 10 [29%]), radiation dermatitis (8 [22%] vs 13 [38%]), increased alanine aminotransferase (12 [33%] vs none), increased aspartate aminotransferase (eight [22%] vs none), and oral mucositis (five [14%] vs eight [24%]). Treatment-related serious adverse events were reported for 16 (44%) patients on pazopanib and 12 (35%) patients on placebo. The most common serious adverse events were dehydration and thromboembolic event (three [8%] each) in patients on pazopanib and oral mucositis (three [8%]) in those on placebo. There was one treatment-related death in each group (sepsis in the pazopanib group and pneumonitis in the placebo group). INTERPRETATION: To our knowledge, this study is the largest randomised anaplastic thyroid cancer study that has completed accrual showing feasibility in a multicenter NCI National Clinical Trials Network setting. Although no significant improvement in overall survival was recorded in the pazopanib group, the treatment combination was shown to be feasible and safe, and hypothesis-generating data that might warrant further investigation were generated. FUNDING: National Cancer Institute and Novartis.


Asunto(s)
Quimioradioterapia , Carcinoma Anaplásico de Tiroides , Neoplasias de la Tiroides , Femenino , Humanos , Masculino , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Método Doble Ciego , Paclitaxel/efectos adversos , Carcinoma Anaplásico de Tiroides/tratamiento farmacológico , Carcinoma Anaplásico de Tiroides/terapia , Neoplasias de la Tiroides/tratamiento farmacológico , Neoplasias de la Tiroides/radioterapia
18.
J Neurosci ; 42(25): 5021-5033, 2022 06 22.
Artículo en Inglés | MEDLINE | ID: mdl-35606144

RESUMEN

Oxytocin (Oxt) neurons regulate diverse physiological responses via direct connections with different neural circuits. However, the lack of comprehensive input-output wiring diagrams of Oxt neurons and their quantitative relationship with Oxt receptor (Oxtr) expression presents challenges to understanding circuit-specific Oxt functions. Here, we establish a whole-brain distribution and anatomic connectivity map of Oxt neurons, and their relationship with Oxtr expression using high-resolution 3D mapping methods in adult male and female mice. We use a flatmap to describe Oxt neuronal expression in four hypothalamic domains including under-characterized Oxt neurons in the tuberal nucleus (TU). Oxt neurons in the paraventricular hypothalamus (PVH) broadly project to nine functional circuits that control cognition, brain state, and somatic visceral response. In contrast, Oxt neurons in the supraoptic (SO) and accessory (AN) nuclei have limited central projection to a small subset of the nine circuits. Surprisingly, quantitative comparison between Oxt output and Oxtr expression showed no significant correlation across the whole brain, suggesting abundant indirect Oxt signaling in Oxtr-expressing areas. Unlike output, Oxt neurons in both the PVH and SO receive similar monosynaptic inputs from a subset of the nine circuits mainly in the thalamic, hypothalamic, and cerebral nuclei areas. Our results suggest that PVH-Oxt neurons serve as a central modulator to integrate external and internal information via largely reciprocal connection with the nine circuits while the SO-Oxt neurons act mainly as unidirectional Oxt hormonal output. In summary, our Oxt wiring diagram provides anatomic insights about distinct behavioral functions of Oxt signaling in the brain.SIGNIFICANCE STATEMENT Oxytocin (Oxt) neurons regulate diverse physiological functions from prosocial behavior to pain sensation via central projection in the brain. Thus, understanding detailed anatomic connectivity of Oxt neurons can provide insight on circuit-specific roles of Oxt signaling in regulating different physiological functions. Here, we use high-resolution mapping methods to describe the 3D distribution, monosynaptic input and long-range output of Oxt neurons, and their relationship with Oxt receptor (Oxtr) expression across the entire mouse brain. We found Oxt connections with nine functional circuits controlling cognition, brain state, and somatic visceral response. Furthermore, we identified a quantitatively unmatched Oxt-Oxtr relationship, suggesting broad indirect Oxt signaling. Together, our comprehensive Oxt wiring diagram advances our understanding of circuit-specific roles of Oxt neurons.


Asunto(s)
Oxitocina , Receptores de Oxitocina , Animales , Encéfalo/metabolismo , Femenino , Masculino , Ratones , Neuronas/metabolismo , Oxitocina/metabolismo , Receptores de Oxitocina/metabolismo , Transducción de Señal
19.
J Am Chem Soc ; 145(4): 2282-2293, 2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36657018

RESUMEN

The palladium complex [(L1)Pd(µ-OAc)]2[OTf]2 (L1 = neocuproine) is a selective catalyst for the aerobic oxidation of vicinal polyols to α-hydroxyketones, but competitive oxidation of the ligand methyl groups limits the turnover number and necessitates high Pd loadings. Replacement of the neocuproine ligand with 2,2'-biquinoline ligands was investigated as a strategy to improve catalyst performance and explore the relationship between ligand structure and reactivity. Evaluation of [(L2)Pd(µ-OAc)]2[OTf]2 (L2 = 2,2'-biquinoline) as a catalyst for aerobic alcohol oxidation revealed a threefold enhancement in turnover number relative to the neocuproine congener, but a much slower rate. Mechanistic studies indicated that the slow rates observed with L2 were a consequence of precipitation of an insoluble trinuclear palladium species─(L2Pd)3(µ-O)22+─formed during catalysis and characterized by high-resolution electrospray ionization mass spectrometry. Density functional theory was used to predict that a sterically modified biquinoline ligand, L3 = 7,7'-di-tert-butyl-2,2'-biquinoline, would disfavor the formation of the trinuclear (LPd)3(µ-O)22+ species. This design strategy was validated as catalytic aerobic oxidation with [(L3)Pd(µ-OAc)]2[OTf]2 is both robust and rapid, marrying the kinetics of the parent L1-supported system with the high aerobic turnover numbers of the L2-supported system. Changes in ligand structure were also found to modulate regioselectivity in the oxidation of complex glycoside substrates, providing new insights into structure-selectivity relationships with this class of catalysts.

20.
J Am Chem Soc ; 145(1): 732-744, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36538761

RESUMEN

Control over the populations of singlet and triplet excitons is key to organic semiconductor technologies. In different contexts, triplets can represent an energy loss pathway that must be managed (i.e., solar cells, light-emitting diodes, and lasers) or provide avenues to improve energy conversion (i.e., photon upconversion and multiplication systems). A key consideration in the interplay of singlet and triplet exciton populations in these systems is the rate of intersystem crossing (ISC). In this work, we design, measure, and model a series of new electron acceptor molecules and analyze them using a combination of ultrafast transient absorption and ultrafast broadband photoluminescence spectroscopies. We demonstrate that intramolecular triplet formation occurs within several hundred picoseconds in solution and is accelerated considerably in the solid state. Importantly, ISC occurs with sufficient rapidity to compete with charge formation in modern organic solar cells, implicating triplets in intrinsic exciton loss channels in addition to charge recombination. Density functional theory calculations reveal that ISC occurs in triplet excited states characterized by local deviations from orbital π-symmetry associated with rotationally flexible thiophene rings. In disordered films, structural distortions, therefore, result in significant increases in spin-orbit coupling, enabling rapid ISC. We demonstrate the generality of this proposal in an oligothiophene model system where ISC is symmetry-forbidden and show that conformational disorder introduced by the formation of a solvent glass accelerates ISC, outweighing the lower temperature and increased viscosity. This proposal sheds light on the factors responsible for facile ISC and provides a simple framework for molecular control over spin states.

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