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1.
Phys Rev Lett ; 127(7): 076802, 2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34459648

RESUMO

Many advancements have been made in the field of topological mechanics. The majority of the work, however, concerns the topological invariant in a linear theory. In this Letter, we present a generic prescription to define topological indices that accommodates nonlinear effects in mechanical systems without taking any approximation. Invoking the tools of differential geometry, a Z-valued quantity in terms of a topological index in differential geometry known as the Poincaré-Hopf index, which features the topological invariant of nonlinear zero modes (ZMs), is predicted. We further identify one type of topologically protected solitons that are robust to disorders. Our prescription constitutes a new direction of searching for novel topologically protected nonlinear ZMs in the future.

2.
Chem Commun (Camb) ; 57(55): 6808-6811, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34142689

RESUMO

The inherent in vivo instability of oligonucleotides presents one of many challenges in the development of RNAi-based therapeutics. Chemical modification to the 5'-terminus serves as an existing paradigm which can make phosphorylated antisense strands less prone to degradation by endogenous enzymes. It has been recently shown that installation of 5'-cyclopropyl phosphonate on the terminus of an oligonucleotide results in greater knockdown of a targeted protein when compared to its unmodified phosphate derivative. In this paper we report the synthesis of a 5'-modified uridine.


Assuntos
Nucleotídeos/química , Nucleotídeos/síntese química , Fosfatos/química , Técnicas de Química Sintética , Uridina/química
3.
Am Psychol ; 76(2): 181-187, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33734787

RESUMO

Adverse childhood experiences (ACEs) detrimentally affect health outcomes in childhood, adolescence, and adulthood. Over the past 2 decades, the recognition of ACEs by scientists and professionals across disciplines, policymakers, and the public has evolved and expanded. Although the initial articulation of ACEs in Felitti et al.'s landmark study has formed the basis of subsequent investigations on the long-term impact of childhood adversities on health and health risk behaviors, a wider public health framework, inclusive of psychology and other social sciences, also shapes current conceptualizations, research, practice, and policies. This article provides an overview of the special issue Adverse Childhood Experiences: Translating Research to Action. Given the rapid expansion and widespread application of ACEs, this special issue was developed to articulate critical concepts, to demonstrate the significance and relevance of psychological research and practice, and to catalyze further efforts to develop effective programs and policies informed by science. The 15 articles included reflect the continuum of critical work being conducted in research, practice, intervention and prevention programs, and public policy and serve to synthesize the growing body of empirical evidence. The overarching themes that emerged are framed as 3 essential questions: (a) How broadly should ACEs be defined?, (b) How should ACEs be assessed?, and (c) How can ACEs science translate into high quality services? As illustrated in these articles, policy and practice applications deriving from psychology as a hub science can substantially benefit the health and mental health of children, adolescents, and adults. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Experiências Adversas da Infância , Política de Saúde , Saúde Mental , Saúde Pública , Adolescente , Adulto , Criança , Humanos
4.
Environ Sci Technol ; 55(5): 2859-2868, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33577293

RESUMO

Ultrafine particles (UFPs) dominate the particle number population in the urban atmosphere and revealing their chemical composition is important. The thermal desorption chemical ionization mass spectrometer (TDCIMS) can semicontinuously measure UFP composition at the molecular level. We modified a TDCIMS and deployed it in urban Beijing. Radioactive materials in the TDCIMS for aerosol charging and chemical ionization were replaced by soft X-ray ionizers so that it can be operated in countries with tight regulations on radioactive materials. Protonated N-methyl-2-pyrrolidone ions were used as the positive reagent ion, which selectively detects ammonia and low-molecular weight-aliphatic amines and amides vaporized from the particle phase. With superoxide as the negative reagent ion, a wide range of inorganic and organic compounds were observed, including nitrate, sulfate, aliphatic acids with carbon numbers up to 18, and highly oxygenated CHO, CHON, and CHOS compounds. The latter two can be attributed to parent ions or the decomposition products of organonitrates and organosulfates/organosulfonates, respectively. Components from both primary emissions and secondary formation of UFPs were identified. Compared to the UFPs measured at forest and marine sites, those in urban Beijing contain more nitrogen-containing and sulfur-containing compounds. These observations illustrate unique features of the UFPs in the urban environment and provide insights into their origins.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , Atmosfera , Pequim , Monitoramento Ambiental , Tamanho da Partícula , Material Particulado/análise
5.
J Rural Health ; 37(3): 504-516, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32881112

RESUMO

PURPOSE: Given that the recent eHealth literacy literature supports the properties of the 3-factor eHealth literacy scale (eHEALS) model in samples with millennials, adults, and older adults, the appropriate next step is to establish whether the model can be reproduced in a rural adolescent sample. The purpose of this study was to evaluate the recent 3-factor model by Paige and associates with a sample of seventh-grade students. METHODS: This cross-sectional study included a subsample of students (n = 146) from 3 school districts in Appalachian Kentucky. We used confirmatory factor analysis (CFA) procedures and small sample model fit guidelines to evaluate our model, and the 1-sample bootstrap algorithm with bias-corrected and accelerated 95% confidence intervals to estimate associations among eHEALS and health and technology variables. FINDINGS: A total of 137 students, or 61% of enrolled seventh-grade students, completed the study. CFA results showed eHEALS 3-factor loadings-information awareness, information seeking, and information engagement-were high (≥0.63) and statistically significant. We observed evidence of a good model fit (root mean square error of approximation [RMSEA] = 0.07, standardized root mean square residual [SRMR] = 0.03, comparative fit index [CFI] = 0.99) and results are comparable with Paige and associates' model fit (RMSEA = 0.06, SRMR = 0.08, CFI = 0.98). Correlations showed that students with more access to technology were associated with higher information seeking (r = 0.31) and higher information engagement (r = 0.23). eHealth literacy scores did not differ by level of rurality or gender. CONCLUSIONS: The 3-factor eHEALS is a reliable and valid instrument in assessing eHealth literacy in a group of rural seventh graders from Appalachian Kentucky.


Assuntos
Letramento em Saúde , Telemedicina , Adolescente , Idoso , Estudos Transversais , Humanos , Reprodutibilidade dos Testes , Estudantes , Inquéritos e Questionários
6.
Sci Adv ; 6(3): eaax9051, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31998839

RESUMO

Aerosol nanoparticles play an important role in the climate system by affecting cloud formation and properties, as well as in human health because of their deep reach into lungs and the circulatory system. Determining nanoparticle sources and composition is a major challenge in assessing their impacts in these areas. The sudden appearance of large numbers of atmospheric nanoparticles is commonly attributed to secondary formation from gas-phase precursors, but in many cases, the evidence for this is equivocal. We report the detection of a mode of fungal fragments with a mobility diameter of roughly 30 nm released in episodic bursts in ambient air over an agricultural area in northern Oklahoma. These events reached concentrations orders of magnitude higher than other reports of biological particles and show similarities to unclarified events reported previously in the Amazon. These particles potentially represent a large source of both cloud-forming ice nuclei and respirable allergens in a variety of ecosystems.


Assuntos
Aerossóis , Fungos , Nanopartículas , Atmosfera , Clima , Microbiologia Ambiental , Humanos , Oklahoma , Tamanho da Partícula
7.
Proc Natl Acad Sci U S A ; 116(27): 13249-13254, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31160468

RESUMO

The CuO2 antiferromagnetic insulator is transformed by hole-doping into an exotic quantum fluid usually referred to as the pseudogap (PG) phase. Its defining characteristic is a strong suppression of the electronic density-of-states D(E) for energies |E| < [Formula: see text], where [Formula: see text] is the PG energy. Unanticipated broken-symmetry phases have been detected by a wide variety of techniques in the PG regime, most significantly a finite-Q density-wave (DW) state and a Q = 0 nematic (NE) state. Sublattice-phase-resolved imaging of electronic structure allows the doping and energy dependence of these distinct broken-symmetry states to be visualized simultaneously. Using this approach, we show that even though their reported ordering temperatures T DW and T NE are unrelated to each other, both the DW and NE states always exhibit their maximum spectral intensity at the same energy, and using independent measurements that this is the PG energy [Formula: see text] Moreover, no new energy-gap opening coincides with the appearance of the DW state (which should theoretically open an energy gap on the Fermi surface), while the observed PG opening coincides with the appearance of the NE state (which should theoretically be incapable of opening a Fermi-surface gap). We demonstrate how this perplexing phenomenology of thermal transitions and energy-gap opening at the breaking of two highly distinct symmetries may be understood as the natural consequence of a vestigial nematic state within the pseudogap phase of Bi2Sr2CaCu2O8.

8.
Science ; 364(6444): 976-980, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31171694

RESUMO

High magnetic fields suppress cuprate superconductivity to reveal an unusual density wave (DW) state coexisting with unexplained quantum oscillations. Although routinely labeled a charge density wave (CDW), this DW state could actually be an electron-pair density wave (PDW). To search for evidence of a field-induced PDW, we visualized modulations in the density of electronic states N(r) within the halo surrounding Bi2Sr2CaCu2O8 vortex cores. We detected numerous phenomena predicted for a field-induced PDW, including two sets of particle-hole symmetric N(r) modulations with wave vectors QP and 2Q P , with the latter decaying twice as rapidly from the core as the former. These data imply that the primary field-induced state in underdoped superconducting cuprates is a PDW, with approximately eight CuO2 unit-cell periodicity and coexisting with its secondary CDWs.

9.
Women Health ; 59(6): 646-659, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30481139

RESUMO

Cancer is the leading cause of death among American Indian and Alaska Native (AIAN) women, and depressive symptoms have been linked to higher mortality, but research on depressive symptoms among AIAN cancer patients has been scant. The purpose of this exploratory study was, using the Framework of Historical Oppression, Resilience, and Transcendence, to examine risk and protective factors related to depressive symptoms in American Indian (AI) women cancer survivors. We examined the relationships of adverse childhood experiences (ACE), perceived health status, resilience, and social support with depressive symptoms in Northern Plains AI women cancer survivors. We used a cross-sectional design with purposive sampling of 73 female cancer survivors (aged 18 years or older) between June 2014 and February 2015. Hierarchical multiple regression was used to test three sets of variables in relation to depressive symptoms: (1) sociodemographics, (2) risk factors (ACE and perceived health), and (3) protective factors (psychological resilience and social support). Approximately 47 percent of participants had probable depressive symptoms. Depressive symptoms were inversely associated with perceived health, psychological resilience, and social support. These results support bolstering existing social support among AI cancer patients and survivors as well as prevention and intervention efforts that strengthen resilience.


Assuntos
Sobreviventes Adultos de Maus-Tratos Infantis/psicologia , Sobreviventes de Câncer/psicologia , Depressão/etnologia , Índios Norte-Americanos/psicologia , Resiliência Psicológica , Apoio Social , Adulto , Sobreviventes Adultos de Maus-Tratos Infantis/estatística & dados numéricos , Estudos Transversais , Depressão/diagnóstico , Depressão/psicologia , Feminino , Nível de Saúde , Humanos , Pessoa de Meia-Idade , Fatores de Proteção , Fatores de Risco , Estados Unidos/epidemiologia
10.
Aerosol Sci Technol ; 53(9): 1023-1039, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-33041429

RESUMO

Waterpipe smoking is becoming more popular worldwide and there is a pressing need to better characterize the exposure of smokers to chemical compounds present in the mainstream smoke. We report real-time measurements of mainstream smoke for carbon monoxide, volatile organic compounds and nanoparticle size distribution and chemical composition using a custom dilution flow tube. A conventional tobacco mixture, a dark leaf unwashed tobacco and a nicotine-free herbal tobacco were studied. Results show that carbon monoxide is present in the mainstream smoke and originates primarily from the charcoal used to heat the tobacco. Online measurements of volatile organic compounds in mainstream smoke showed an overwhelming contribution from glycerol. Gas phase analysis also showed that very little filtration of the gas phase products is provided by the percolation of mainstream smoke through water. Waterpipe smoking generated high concentrations of 4-100 nm nanoparticles, which were mainly composed of sugar derivatives and especially abundant in the first 10 min of the smoking session. These measured emissions of volatiles and particles are compared with those from a reference cigarette (3R4F) and represent the equivalent of the emission of one or more entire cigarettes for a single puff of hookah smoke. Considerations related to the health impacts of waterpipe smoking are discussed.

11.
Child Dev ; 90(2): 395-413, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30171770

RESUMO

This study tests an ecological, relationship-based model of children's subjective well-being with 9- to 14-year-old children (n = 25,906) from 14 countries across Africa, Asia, Europe, North America, and South America. Children completed the Children's Worlds survey, a self-report measure of contextual and well-being indicators. Multilevel modeling was used to predict children's well-being (life satisfaction and self-image) at two levels, child (age, gender, home context, family relationships, peer relationships, school context, teacher relationships, and neighborhood quality), and country (gross domestic product and income inequality). Findings indicated that intercepts varied significantly across countries. The majority of variance in children's well-being was attributed to child-level rather than country-level factors. Country-level factors did not strongly predict well-being but marginally improved model fit.


Assuntos
Desenvolvimento Infantil , Proteção da Criança , Comparação Transcultural , Qualidade de Vida/psicologia , Adolescente , Criança , Estudos Transversais , Relações Familiares , Feminino , Humanos , Relações Interpessoais , Masculino , Modelos Psicológicos , Análise Multinível , Autorrelato , Meio Social , Fatores Socioeconômicos , Inquéritos e Questionários
12.
Sci Adv ; 4(12): eaau5363, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30547087

RESUMO

A major fraction of atmospheric aerosol particles, which affect both air quality and climate, form from gaseous precursors in the atmosphere. Highly oxygenated organic molecules (HOMs), formed by oxidation of biogenic volatile organic compounds, are known to participate in particle formation and growth. However, it is not well understood how they interact with atmospheric pollutants, such as nitrogen oxides (NO x ) and sulfur oxides (SO x ) from fossil fuel combustion, as well as ammonia (NH3) from livestock and fertilizers. Here, we show how NO x suppresses particle formation, while HOMs, sulfuric acid, and NH3 have a synergistic enhancing effect on particle formation. We postulate a novel mechanism, involving HOMs, sulfuric acid, and ammonia, which is able to closely reproduce observations of particle formation and growth in daytime boreal forest and similar environments. The findings elucidate the complex interactions between biogenic and anthropogenic vapors in the atmospheric aerosol system.

13.
Phys Rev Lett ; 121(23): 237002, 2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30576170

RESUMO

Despite its seemingly simple composition and structure, the pairing mechanism of FeSe remains an open problem due to several striking phenomena. Among them are nematic order without magnetic order, nodeless gap and unusual inelastic neutron spectra with a broad continuum, and gap anisotropy consistent with orbital selection of unknown origin. Here we propose a microscopic description of a nematic quantum spin liquid that reproduces key features of neutron spectra. We then study how the spin fluctuations of the local moments lead to pairing within a spin-fermion model. We find the resulting superconducting order parameter to be nodeless s±d wave within each domain. Further we show that orbital dependent Kondo-like coupling can readily capture observed gap anisotropy. Our prediction calls for inelastic neutron scattering in a detwinned sample.

14.
Phys Rev Lett ; 121(18): 187001, 2018 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-30444391

RESUMO

A mysterious incoherent metallic (IM) normal state with T-linear resistivity is ubiquitous among strongly correlated superconductors. Recent progress with microscopic models exhibiting IM transport has presented the opportunity for us to study new models that exhibit direct transitions into a superconducting state out of IM states within the framework of connected Sachdev-Ye-Kitaev "quantum dots." Here, local Sachdev-Ye-Kitaev interactions within a dot produce IM transport in the normal state, while local attractive interactions drive superconductivity. Through explicit calculations, we find two features of superconductivity arising from an IM normal state. First, despite the absence of quasiparticles in the normal state, the superconducting state still exhibits coherent superfluid transport. Second, the nonquasiparticle nature of the IM Green's functions produces a large enhancement in the ratio of the zero-temperature superconducting gap Δ and transition temperature T_{SC}, 2Δ/T_{SC}, with respect to its BCS value of 3.53.

15.
Phys Rev Lett ; 121(17): 177201, 2018 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-30411943

RESUMO

Kagome antiferromagnets are known to be highly frustrated and degenerate when they possess simple, isotropic interactions. We consider the entire class of these magnets when their interactions are spatially anisotropic. We do so by identifying a certain class of systems whose degenerate ground states can be mapped onto the folding motions of a generalized "spin origami" two-dimensional mechanical sheet. Some such anisotropic spin systems, including Cs_{2}ZrCu_{3}F_{12}, map onto flat origami sheets, possessing extensive degeneracy similar to isotropic systems. Others, such as Cs_{2}CeCu_{3}F_{12}, can be mapped onto sheets with nonzero Gaussian curvature, leading to more mechanically stable corrugated surfaces. Remarkably, even such distortions do not always lift the entire degeneracy, instead permitting a large but subextensive space of zero-energy modes. We show that for Cs_{2}CeCu_{3}F_{12}, due to an additional point group symmetry associated with the structure, these modes are "Dirac" line nodes with a double degeneracy protected by a topological invariant. The existence of mechanical analogs thus serves to identify and explicate the robust degeneracy of the spin systems.

16.
J Interpers Violence ; 33(18): 2826-2848, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-26912487

RESUMO

This study examined the association between childhood maltreatment and intimate partner violence (IPV) victimization among Native American adults. Based on Riggs's theoretical model of the long-term effects of childhood abuse, we also examined the mediating roles of insecure attachment patterns and depressive symptoms. The current study was a secondary data analysis using the 2013 General Well-Being Among Native Americans dataset ( N = 479). Structural equation modeling was used to examine the hypothesized relationships among key constructs. Consistent with existing literature of revictimization, our findings showed that the experience of childhood maltreatment was positively associated with IPV victimization. Mediation analyses indicated that depression was a significant mediator in the association between childhood maltreatment and IPV victimization. In addition, all the paths linking childhood maltreatment, fearful attachment, depressive symptoms, and IPV victimization were statistically significant, although the overall mediation effect was not significant. The results of this study suggest that Riggs's model can serve as a useful theoretical framework for understanding the long-term effects of childhood maltreatment among Native American adults. Practitioners in the area of IPV should include maltreatment history and current attachment patterns in client assessments, which could help address conflict and violence within intimate relationships.


Assuntos
Bullying , Maus-Tratos Infantis , Vítimas de Crime , Índios Norte-Americanos , Violência por Parceiro Íntimo , Adulto , Criança , Maus-Tratos Infantis/etnologia , Depressão , Transtorno Depressivo , Medo , Feminino , Humanos , Índios Norte-Americanos/psicologia , Relações Interpessoais , Violência por Parceiro Íntimo/etnologia , Masculino , Grupos Minoritários , Comportamento Sexual , Parceiros Sexuais , Violência
17.
J Appl Gerontol ; 36(1): 94-115, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25416511

RESUMO

American Indian (AI) older adults are vulnerable to mental health disparities, yet very little is known about the factors associated with help-seeking for mental health services among them. The purpose of this study was to investigate the utility of Andersen's Behavioral Model in explaining AI older adults' help-seeking attitudes toward professional mental health services. Hierarchical regression analysis was used to examine predisposing, enabling, and need variables as predictors of help-seeking attitudes toward mental health services in a sample of 233 AI older adults from the Midwest. The model was found to have limited utility in the context of older AI help-seeking attitudes, as the proportion of explained variance was low. Gender, perceived stigma, social support, and physical health were significant predictors, whereas age, perceived mental health, and health insurance were not.


Assuntos
Índios Norte-Americanos/psicologia , Serviços de Saúde Mental/estatística & dados numéricos , Modelos Psicológicos , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Idoso , Idoso de 80 Anos ou mais , Atitude/etnologia , Feminino , Nível de Saúde , Humanos , Masculino , Saúde Mental , Pessoa de Meia-Idade , Fatores Sexuais , Estigma Social , Apoio Social , Inquéritos e Questionários , Estados Unidos
18.
Science ; 354(6316): 1119-1124, 2016 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-27789796

RESUMO

Fundamental questions remain about the origin of newly formed atmospheric aerosol particles because data from laboratory measurements have been insufficient to build global models. In contrast, gas-phase chemistry models have been based on laboratory kinetics measurements for decades. We built a global model of aerosol formation by using extensive laboratory measurements of rates of nucleation involving sulfuric acid, ammonia, ions, and organic compounds conducted in the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber. The simulations and a comparison with atmospheric observations show that nearly all nucleation throughout the present-day atmosphere involves ammonia or biogenic organic compounds, in addition to sulfuric acid. A considerable fraction of nucleation involves ions, but the relatively weak dependence on ion concentrations indicates that for the processes studied, variations in cosmic ray intensity do not appreciably affect climate through nucleation in the present-day atmosphere.

19.
Proc Natl Acad Sci U S A ; 113(45): 12661-12666, 2016 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-27791157

RESUMO

Theories based upon strong real space (r-space) electron-electron interactions have long predicted that unidirectional charge density modulations (CDMs) with four-unit-cell (4a0) periodicity should occur in the hole-doped cuprate Mott insulator (MI). Experimentally, however, increasing the hole density p is reported to cause the conventionally defined wavevector QA of the CDM to evolve continuously as if driven primarily by momentum-space (k-space) effects. Here we introduce phase-resolved electronic structure visualization for determination of the cuprate CDM wavevector. Remarkably, this technique reveals a virtually doping-independent locking of the local CDM wavevector at [Formula: see text] throughout the underdoped phase diagram of the canonical cuprate Bi2Sr2CaCu2O8 These observations have significant fundamental consequences because they are orthogonal to a k-space (Fermi-surface)-based picture of the cuprate CDMs but are consistent with strong-coupling r-space-based theories. Our findings imply that it is the latter that provides the intrinsic organizational principle for the cuprate CDM state.

20.
Nat Commun ; 7: 11594, 2016 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-27197574

RESUMO

The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at sub-3 nm sizes with different atmospherically relevant concentrations of sulphuric acid, water, ammonia and dimethylamine. We find that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process, leading to enhanced growth rates. The availability of compounds capable of stabilizing sulphuric acid clusters governs the magnitude of these effects and thus the exact growth mechanism. We bring these observations into a coherent framework and discuss their significance in the atmosphere.

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