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1.
Nature ; 569(7757): E9, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31073227

RESUMO

Change history: In this Letter, the y-axis values in Fig. 3f should go from 4 to -8 (rather than from 4 to -4), the y-axis values in Fig. 3h should appear next to the major tick marks (rather than the minor ticks), and in Fig. 1b, the arrows at the top and bottom of the electron-scale current sheet were going in the wrong direction; these errors have been corrected online.

2.
J Sex Marital Ther ; 50(4): 527-541, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38567544

RESUMO

This study examines dyadic data from 299 married and 242 cohabiting Black heterosexual couples in the United States (an understudied cross-section of the population) and assesses individual (actor) effects as well as couple (partner) effects of sexual sanctification and relationship satisfaction. Higher levels of sexual sanctification were associated with higher levels of relationship satisfaction for women and men in the actor effects, but no significant associations were found in the partner effects for couples. Additionally, initial findings suggest that sexual sanctification may act as a relational protective factor for Black married and cohabiting couples. Implications for further research as well as practical applications for clergy, therapists, and practitioners working with Black heterosexual couples in sexual relationships are also discussed.


Assuntos
Negro ou Afro-Americano , Heterossexualidade , Satisfação Pessoal , Parceiros Sexuais , Humanos , Masculino , Feminino , Heterossexualidade/psicologia , Adulto , Negro ou Afro-Americano/psicologia , Parceiros Sexuais/psicologia , Estados Unidos , Relações Interpessoais , Comportamento Sexual/psicologia , Pessoa de Meia-Idade , Cônjuges/psicologia , Casamento/psicologia
3.
Nature ; 557(7704): 202-206, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29743689

RESUMO

Magnetic reconnection in current sheets is a magnetic-to-particle energy conversion process that is fundamental to many space and laboratory plasma systems. In the standard model of reconnection, this process occurs in a minuscule electron-scale diffusion region1,2. On larger scales, ions couple to the newly reconnected magnetic-field lines and are ejected away from the diffusion region in the form of bi-directional ion jets at the ion Alfvén speed3-5. Much of the energy conversion occurs in spatially extended ion exhausts downstream of the diffusion region 6 . In turbulent plasmas, which contain a large number of small-scale current sheets, reconnection has long been suggested to have a major role in the dissipation of turbulent energy at kinetic scales7-11. However, evidence for reconnection plasma jetting in small-scale turbulent plasmas has so far been lacking. Here we report observations made in Earth's turbulent magnetosheath region (downstream of the bow shock) of an electron-scale current sheet in which diverging bi-directional super-ion-Alfvénic electron jets, parallel electric fields and enhanced magnetic-to-particle energy conversion were detected. Contrary to the standard model of reconnection, the thin reconnecting current sheet was not embedded in a wider ion-scale current layer and no ion jets were detected. Observations of this and other similar, but unidirectional, electron jet events without signatures of ion reconnection reveal a form of reconnection that can drive turbulent energy transfer and dissipation in electron-scale current sheets without ion coupling.

4.
J Clin Child Adolesc Psychol ; : 1-15, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38530356

RESUMO

OBJECTIVE: Current antibullying programs can reduce overall rates of victimization but appear to overlook processes that give rise to persistent peer victimization. Needed are studies that delineate the interplay between social contextual and individual difference variables that contribute to persistent peer victimization. We examined the extent to which two individual-difference variables - internalizing symptoms (IS) and anxiety sensitivity (AS) - moderated the link between children's average social preference score across the school year and their status as persistent victims. METHOD: Participants included 659 4th-grade students (Mage = 9.31 years, SD = 0.50, 51.8% girls; 42.3% Latinx, 28.9% non-Hispanic White, 10.2% Pacific Islander, 7.7% Bi/Multiracial, 1.9% Black, 1.7% Asian, 1.7% Native American, and 3.4% unreported) from 10 public elementary schools in the U.S. RESULTS: As expected, higher social preference scores predicted a decreased likelihood of being persistently victimized. Conversely, IS and AS were positively linked to persistent victim status. AS significantly moderated the link between social preference and persistent victim status such that for children with high AS, compared to those with AS scores at or below the mean, the negative association between social preference and persistent victim status was attenuated. CONCLUSIONS: Findings provide evidence that children who experience high levels of IS and AS are at risk for being persistently victimized by peers and that high AS could signal increased risk for persistent victimization even when children are generally liked by peers. We discuss the implications of these findings for efforts to develop focused interventions for chronically bullied children.

5.
J Intellect Disabil Res ; 68(4): 369-376, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38229473

RESUMO

BACKGROUND: Neurocognitive functioning is an integral phenotype of 22q11.2 deletion syndrome relating to severity of psychopathology and outcomes. A neurocognitive battery that could be administered remotely to assess multiple cognitive domains would be especially beneficial to research on rare genetic variants, where in-person assessment can be unavailable or burdensome. The current study compares in-person and remote assessments of the Penn computerised neurocognitive battery (CNB). METHODS: Participants (mean age = 17.82, SD = 6.94 years; 48% female) completed the CNB either in-person at a laboratory (n = 222) or remotely (n = 162). RESULTS: Results show that accuracy of CNB performance was equivalent across the two testing locations, while slight differences in speed were detected in 3 of the 11 tasks. CONCLUSIONS: These findings suggest that the CNB can be used in remote settings to assess multiple neurocognitive domains.


Assuntos
Síndrome de DiGeorge , Humanos , Feminino , Adolescente , Masculino , Síndrome de DiGeorge/complicações , Síndrome de DiGeorge/psicologia , Cognição , Testes Neuropsicológicos , Psicopatologia , Fenótipo
6.
Photosynth Res ; 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37910331

RESUMO

Hybrid complexes incorporating synthetic Mn-porphyrins into an artificial four-helix bundle domain of bacterial reaction centers created a system to investigate new electron transfer pathways. The reactions were initiated by illumination of the bacterial reaction centers, whose primary photochemistry involves electron transfer from the bacteriochlorophyll dimer through a series of electron acceptors to the quinone electron acceptors. Porphyrins with diphenyl, dimesityl, or fluorinated substituents were synthesized containing either Mn or Zn. Electrochemical measurements revealed potentials for Mn(III)/Mn(II) transitions that are ~ 0.4 V higher for the fluorinated Mn-porphyrins than the diphenyl and dimesityl Mn-porphyrins. The synthetic porphyrins were introduced into the proteins by binding to a four-helix bundle domain that was genetically fused to the reaction center. Light excitation of the bacteriochlorophyll dimer of the reaction center resulted in new derivative signals, in the 400 to 450 nm region of light-minus-dark spectra, that are consistent with oxidation of the fluorinated Mn(II) porphyrins and reduction of the diphenyl and dimesityl Mn(III) porphyrins. These features recovered in the dark and were not observed in the Zn(II) porphyrins. The amplitudes of the signals were dependent upon the oxidation/reduction midpoint potentials of the bacteriochlorophyll dimer. These results are interpreted as photo-induced charge-separation processes resulting in redox changes of the Mn-porphyrins, demonstrating the utility of the hybrid artificial reaction center system to establish design guidelines for novel electron transfer reactions.

7.
Diabet Med ; 40(4): e15035, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36576331

RESUMO

AIMS: Facilitated self-management support programmes have become central to the treatment of chronic diseases including diabetes. For many children and young people with diabetes (CYPD), the impact on glycated haemoglobin (HbA1c ) and a range of self-management behaviours promised by these programmes remain unrealised. This warrants an appraisal of current thinking and the existing evidence to guide the development of programmes better targeted at this age group. METHODS: Create a narrative review of systematic reviews produced in the last 3 years that have explored the impact on CYPD of the four key elements of self-management support programmes: education, instruction and advice including peer support; psychological counselling via a range of therapies; self-monitoring, including diaries and telemetric devices; and telecare, the technology-enabled follow-up and support by healthcare providers. RESULTS: Games and gamification appear to offer a promising means of engaging and educating CYPD. Psychological interventions when delivered by trained practitioners, appear to improve HbA1c and quality of life although effect sizes were small. Technology-enabled interactive diaries can increase the frequency of self-monitoring and reduce levels of HbA1c . Telecare provided synchronously via telephone produced significant improvements in HbA1c . CONCLUSIONS: The cost-effective flexibility of increasing the reliance on technology is an attractive proposition; however, there are resource implications for digital connectivity in underserved populations. The need remains to improve the understanding of which elements of each component are most effective in a particular context, and how to optimise the influence and input of families, caregivers and peers.


Assuntos
Diabetes Mellitus , Autogestão , Humanos , Criança , Adolescente , Qualidade de Vida , Revisões Sistemáticas como Assunto , Telefone
8.
Gastrointest Endosc ; 94(1): 60-67.e1, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33385462

RESUMO

BACKGROUND AND AIMS: Portal pressure can be used to identify patients with chronic liver disease who have progressed to cirrhosis. Portal pressure can also provide accurate prognostication for patients with cirrhosis. However, there are no practical means for assessment of portal pressure. Although it is well established that the gastric mucosal blood supply increases in patients with cirrhosis, this has been difficult to quantify reproducibly. Our group has developed a novel spectroscopic technology called spatially resolved subdiffuse reflectance spectroscopy (SRSRS), which enables quantification of mucosal microcirculation. We aim to ascertain if quantification of the gastric mucosal microcirculation with SRSRS correlates with clinical evidence of portal hypertension. METHODS: Patients undergoing EGD for clinical indications had 10 measurements taken in the endoscopically normal gastric fundus via SRSRS probe to assess the microcirculation. Cases were defined as patients with cirrhosis (n = 18), and controls were those without evidence of liver disease (n = 18); this was corroborated with transient elastography. RESULTS: The blood volume fraction (P = .06) and subdiffuse reflectance (P = .02) from a shallow depth in the gastric fundus were higher in patients with cirrhosis than those without. These markers were combined to yield an overall optical marker that can differentiate patients with cirrhosis from controls with a sensitivity of 72% and specificity of 94% (area under receiver operating curve, 0.82). CONCLUSIONS: Spectroscopic quantification of gastric fundal mucosal microcirculation is a promising surrogate of clinical correlates of portal hypertension. This approach may represent a less-intrusive surrogate biomarker for liver disease prognostication and potentially response to therapy.


Assuntos
Hipertensão Portal , Biomarcadores , Mucosa Gástrica , Humanos , Hipertensão Portal/diagnóstico por imagem , Cirrose Hepática/complicações , Cirrose Hepática/diagnóstico por imagem , Microcirculação , Análise Espectral
9.
Rheumatol Int ; 41(6): 1089-1096, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32797279

RESUMO

Objective methods are needed to quantify digital artery disease in systemic sclerosis (SSc) for clinical trials of vascular therapies. Our primary aim was to examine feasibility of a novel tomographic three-dimensional-(3-D) ultrasound (tUS) with high-frequency ultrasound (HFUS) or ultra-high-frequency ultrasound (UHFUS) to assess the digital arteries in patients with SSc compared to healthy controls. A secondary objective was to compare the total wall volume (TWV) as a measure of intimal/medial thickness. Eighteen patients with a confirmed diagnosis of SSc were studied by tUS HFUS (17.5 MHz, n = 10) or tUS UHFUS (48 and 70 MHz, n = 8) with equal numbers of healthy controls of similar age and gender. The majority of patients had limited cutaneous SSc and were representative of a spectrum of digital vasculopathy, with over half (n = 6 HFUS and n = 5 UHFUS) having previous digital ulceration. Over half were receiving oral vasodilatory therapy. TWV was measured in both digital arteries of the middle finger bilaterally. At least, two digital arteries could be identified at 17.5 MHz in all patients and healthy controls. Whereas, at least two digital arteries could be identified in relatively fewer patients compared to healthy controls using 48 MHz (n = 6 and 10) and especially 70 MHz (n = 4 and 10) UHFUS. The median difference in TWV between patients and healthy controls was -6.49 mm3 using 17.5 MHz, 1.9 mm3 at 48 MHz, and -0.4 mm3 at 70 MHz. tUS using UHFUS is a feasible method to measure TWV of digital arteries in SSc. Transducer frequency plays an important factor in successful digital artery measurement, with 48 MHz being the optimal frequency.


Assuntos
Artérias/diagnóstico por imagem , Dedos/irrigação sanguínea , Escleroderma Sistêmico/complicações , Idoso , Estudos de Casos e Controles , Estudos Transversais , Feminino , Dedos/diagnóstico por imagem , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Escleroderma Sistêmico/fisiopatologia , Tomografia Computadorizada por Raios X , Ultrassonografia
10.
Anal Chem ; 92(2): 2052-2057, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31874025

RESUMO

Cortisol is an important steroid hormone in human physiology. Variations or abnormalities in the physiological cortisol levels control acute and chronic stress response, as well as contribute to diseases and syndromes including Addison's disease and Cushing syndrome. The ability to monitor cortisol levels in the physiological range is key in diagnosis and monitoring of these conditions, where current methodology for determination of cortisol levels relies on instrumentation that requires extensive sample preparation, long run times, and is destructive to the sample. Raman spectroscopy provides rapid sample analysis with relatively simple instrumentation; however, Raman spectroscopy is an inherently weak technique. To provide an enhanced Raman signal, we use surface enhanced Raman spectroscopy (SERS) which utilizes oscillating electric fields of metal nanoparticles, enhancing the overall electric field and therefore resulting in an enhanced signal. We demonstrate SERS-based detection of cortisol in the physiologically relevant range using colloidal silver nanoparticles in ethanolic solutions and bovine serum albumin. The SERS spectra obtained in an ethanol matrix demonstrate a sigmoidal concentration response over the physiologically relevant concentration range, with a limit of detection established at 177 nM. Analysis of cortisol solutions in a complex matrix (bovine serum albumin in phosphate buffered saline) is also demonstrated through the use of principal components analysis, a multivariate technique, which shows the separation of cortisol in a linear fashion with respect to cortisol concentration.


Assuntos
Hidrocortisona/análise , Animais , Bovinos , Teoria da Densidade Funcional , Hidroxilamina/química , Nanopartículas Metálicas/química , Conformação Molecular , Soroalbumina Bovina/química , Prata/química , Análise Espectral Raman , Propriedades de Superfície
11.
Phys Rev Lett ; 125(2): 025103, 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32701350

RESUMO

We report measurements of lower-hybrid drift waves driving electron heating and vortical flows in an electron-scale reconnection layer under a guide field. Electrons accelerated by the electrostatic potential of the waves exhibit perpendicular and nongyrotropic heating. The vortical flows generate magnetic field perturbations comparable to the guide field magnitude. The measurements reveal a new regime of electron-wave interaction and how this interaction modifies the electron dynamics in the reconnection layer.

12.
Scand J Rheumatol ; 49(3): 239-243, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31928291

RESUMO

Objective: Despite being a cardinal clinical sign of systemic sclerosis (SSc), digital pitting has been little studied. Our objective was to test, in a pilot study, the hypothesis that pitting is painful and associated with digital vascular disease severity.Method: Fifty patients with SSc were recruited: 25 with and 25 without digital pitting. Fingertip pain was assessed on a 0-10 scale. Thermography of both hands assessed surface temperature, allowing calculation of the distal-dorsal difference (temperature gradient) for each finger. Nailfold capillaroscopy was performed in each finger using a dermatoscope, and graded on a 0-3 scale (0 = normal; 3 = grossly abnormal).Results: In the 25 patients with digital pitting, 65 fingers in total were affected (mainly the index and middle fingers). Pain scores were higher in 'pitting' patients [median 4 (interquartile range 3-8) vs 0 (0-2), p < 0.001], and pitting patients reported that pitting impacted on activities of everyday living. Temperature gradients along the fingers did not differ significantly between patients with and without pitting (p = 0.248). Pitting patients were more likely to have 'grossly abnormal' capillaries than those without pitting, and less likely to have 'no/mild' nailfold capillary changes.Conclusions: Digital pitting is painful and impacts on hand function. Capillaroscopy findings provide further support for an association between pitting and severity of digital vascular change. Larger, more comprehensive studies are required to examine the pathophysiology of pitting and to pave the way to therapeutic intervention, ideally including preventive strategies.


Assuntos
Dedos/fisiopatologia , Dor/fisiopatologia , Esclerodermia Difusa/fisiopatologia , Esclerodermia Limitada/fisiopatologia , Idoso , Estudos de Casos e Controles , Feminino , Dedos/irrigação sanguínea , Dedos/patologia , Humanos , Masculino , Angioscopia Microscópica , Pessoa de Meia-Idade , Dor/etiologia , Projetos Piloto , Esclerodermia Difusa/complicações , Esclerodermia Difusa/patologia , Esclerodermia Limitada/complicações , Esclerodermia Limitada/patologia , Escleroderma Sistêmico/fisiopatologia , Venenos de Escorpião , Índice de Gravidade de Doença , Úlcera Cutânea/etiologia , Termografia
13.
Mol Psychiatry ; 23(10): 1981-1989, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-28924181

RESUMO

The high comorbidity among neuropsychiatric disorders suggests a possible common neurobiological phenotype. Resting-state regional cerebral blood flow (CBF) can be measured noninvasively with magnetic resonance imaging (MRI) and abnormalities in regional CBF are present in many neuropsychiatric disorders. Regional CBF may also provide a useful biological marker across different types of psychopathology. To investigate CBF changes common across psychiatric disorders, we capitalized upon a sample of 1042 youths (ages 11-23 years) who completed cross-sectional imaging as part of the Philadelphia Neurodevelopmental Cohort. CBF at rest was quantified on a voxelwise basis using arterial spin labeled perfusion MRI at 3T. A dimensional measure of psychopathology was constructed using a bifactor model of item-level data from a psychiatric screening interview, which delineated four factors (fear, anxious-misery, psychosis and behavioral symptoms) plus a general factor: overall psychopathology. Overall psychopathology was associated with elevated perfusion in several regions including the right dorsal anterior cingulate cortex (ACC) and left rostral ACC. Furthermore, several clusters were associated with specific dimensions of psychopathology. Psychosis symptoms were related to reduced perfusion in the left frontal operculum and insula, whereas fear symptoms were associated with less perfusion in the right occipital/fusiform gyrus and left subgenual ACC. Follow-up functional connectivity analyses using resting-state functional MRI collected in the same participants revealed that overall psychopathology was associated with decreased connectivity between the dorsal ACC and bilateral caudate. Together, the results of this study demonstrate common and dissociable CBF abnormalities across neuropsychiatric disorders in youth.


Assuntos
Circulação Cerebrovascular/fisiologia , Transtornos Mentais/fisiopatologia , Psicopatologia/métodos , Adolescente , Biomarcadores/sangue , Encéfalo/patologia , Mapeamento Encefálico/métodos , Córtex Cerebral/fisiopatologia , Criança , Feminino , Giro do Cíngulo/diagnóstico por imagem , Giro do Cíngulo/fisiopatologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Transtornos Mentais/diagnóstico por imagem , Transtornos Mentais/metabolismo , Philadelphia , Adulto Jovem
14.
Scand J Rheumatol ; 48(3): 230-234, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30394164

RESUMO

OBJECTIVE: The burden of disability associated with systemic sclerosis (SSc) is being increasingly recognized. Our aim was to test the hypothesis that changes in functional ability over time differ between patients with limited (lcSSc) and diffuse cutaneous (dcSSc) subtypes, and that in dcSSc (but not lcSSc) these changes correlate with skin thickening. METHOD: This was a retrospective analysis of data collected prospectively between 2005 and 2016 at a single centre. Data recorded at annual review visits included modified Rodnan skin score (mRSS) and Health Assessment Questionnaire Disability Index (HAQ-DI). Yearly rates of mRSS and HAQ-DI change were assessed by individual linear regressions, and those gradients were compared between disease groups (lcSSc/dcSSc) for each of early/late disease (less/greater than 5 years' duration). RESULTS: The study included 402 patients (110 dcSSc, 292 lcSSc), with mean length of follow-up of 5.5 years (sd 3.5). Mean baseline HAQ-DI was 1.4 in dcSSc and 1.2 in lcSSc. In dcSSc, increased mRSS was associated with worsening disability (ρ = 0.36, p = 0.004) during early but not late disease (ρ = 0.12, p = 0.331). In lcSSc, changes in mRSS were not associated with changes in disability for early (ρ = -0.15, p = 0.173) or late disease (ρ = 0.10, p = 0.137). CONCLUSION: These findings confirm high disability in patients with SSc. A relationship between HAQ-DI and mRSS (worsening mRSS associated with increasing disability) was found only in patients with early dcSSc, suggesting that in other patient subgroups other factors play the major role.


Assuntos
Efeitos Psicossociais da Doença , Desempenho Físico Funcional , Esclerodermia Difusa , Esclerodermia Localizada , Pele/patologia , Adulto , Avaliação da Deficiência , Progressão da Doença , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Estudos Retrospectivos , Esclerodermia Difusa/patologia , Esclerodermia Difusa/fisiopatologia , Esclerodermia Localizada/patologia , Esclerodermia Localizada/fisiopatologia , Índice de Gravidade de Doença , Reino Unido/epidemiologia
15.
Br J Surg ; 105(4): 388-394, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29210064

RESUMO

BACKGROUND: A significant proportion of donation after circulatory death (DCD) kidneys are declined for transplantation because of concerns over their quality. Ex vivo normothermic machine perfusion (NMP) provides a unique opportunity to assess the quality of a kidney and determine its suitability for transplantation. METHODS: In phase 1 of this study, declined human DCD kidneys underwent NMP assessment for 60 min. Kidneys were graded 1-5 using a quality assessment score (QAS) based on macroscopic perfusion, renal blood flow and urine output during NMP. In phase 2 of the study, declined DCD kidneys were assessed by NMP with an intention to transplant them. RESULTS: In phase 1, 18 of 42 DCD kidneys were declined owing to poor in situ perfusion. After NMP, 28 kidneys had a QAS of 1-3, and were considered suitable for transplantation. In phase 2, ten of 55 declined DCD kidneys underwent assessment by NMP. Eight kidneys had been declined because of poor in situ flushing in the donor and five of these were transplanted successfully. Four of the five kidneys had initial graft function. CONCLUSION: NMP technology can be used to increase the number of DCD kidney transplants by assessing their quality before transplantation.


Assuntos
Seleção do Doador , Transplante de Rim , Rim/irrigação sanguínea , Preservação de Órgãos/métodos , Perfusão/métodos , Adulto , Idoso , Morte , Feminino , Humanos , Rim/fisiologia , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Temperatura
16.
Phys Rev Lett ; 121(26): 265101, 2018 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-30636132

RESUMO

We study spectral features of ion velocity and magnetic field correlations in the magnetosheath and in the solar wind using data from the Magnetospheric Multiscale (MMS) spacecraft. High-resolution MMS observations enable the study of the transition of these correlations between their magnetofluid character at larger scales into the subproton kinetic range, previously unstudied in spacecraft data. Cross-helicity, angular alignment, and energy partitioning is examined over a suitable range of scales, employing measurements based on the Taylor frozen-in approximation as well as direct two-spacecraft correlation measurements. The results demonstrate signatures of alignment at large scales. As kinetic scales are approached, the alignment between v and b is destroyed by demagnetization of protons.

17.
Phys Rev Lett ; 120(22): 225101, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29906189

RESUMO

Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.

18.
Appl Opt ; 57(13): 3444-3452, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29726529

RESUMO

An analysis of time-resolved electronic speckle pattern interferograms using an optimization algorithm is shown to provide full-field measurements of transient surface deformation. The arrangement uses a continuous-wave laser and high-speed camera to capture speckle images, with the recovery of the time-resolved deformation achieved by spatiotemporal processing using an optimization algorithm. It is shown that the process allows imaging of high-speed non-monotonic out-of-plane displacements with sub-micrometer amplitude. Time-resolved amplitude and phase recovery is demonstrated by analyzing the out-of-plane deformation of harmonic and transient events in a friction membranophone.

19.
Microvasc Res ; 111: 32-36, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28027937

RESUMO

OBJECTIVES: In patients with systemic sclerosis (SSc), fingertip digital ulcers (DUs) are believed to be ischaemic, and extensor surface DUs a result of mechanical factors/microtrauma. Our aim was to assess blood flow response to topical glyceryl trinitrate (GTN) compared to placebo in SSc DUs, looking for differences in pathophysiology between fingertip and extensor lesions. METHOD: This was a double-blind, randomised, crossover, placebo-controlled study. Sixteen (6 fingertip, 10 extensor) DUs were each studied twice (one day apart): once with GTN and once with placebo ointment. Perfusion at the DU centre ('DUCore') and periphery ('DUPeriphery'), as measured by laser Doppler imaging was performed before and immediately after ointment application, then every 10min, up to 90min post-application. We calculated the area under the response curve (AUC) and the ratio of peak perfusion to baseline, then compared these between GTN and placebo. RESULTS: Perfusion was lower in the DUCore compared to the DUPeriphery (ratio of 0.52). The microvessels of the DUCore were responsive to GTN, with an increase in perfusion, with a similar effect in both fingertip and extensor DUs. The AUC and peak/baseline perfusion difference in means (ratio, 95% confidence interval) between GTN and placebo at the DUCore were 1.2 (1.0-1.6) and 1.2 (1.0-1.5) respectively, and at the DUPeriphery were 1.1 (0.8-1.6) and 1.0 (0.9-1.2) respectively. CONCLUSION: DUs (both fingertip and extensor) were responsive to topical GTN, with an increase in perfusion to the ischaemic DU centre. If both fingertip and extensor DUs have a (potentially reversible) ischaemic aetiology, this has important treatment implications.


Assuntos
Dedos/irrigação sanguínea , Isquemia/tratamento farmacológico , Microcirculação/efeitos dos fármacos , Nitroglicerina/administração & dosagem , Doença de Raynaud/tratamento farmacológico , Escleroderma Sistêmico/tratamento farmacológico , Úlcera Cutânea/tratamento farmacológico , Vasodilatação/efeitos dos fármacos , Vasodilatadores/administração & dosagem , Administração Cutânea , Adulto , Idoso , Velocidade do Fluxo Sanguíneo , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Isquemia/diagnóstico , Isquemia/fisiopatologia , Fluxometria por Laser-Doppler , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão/métodos , Doença de Raynaud/diagnóstico , Doença de Raynaud/fisiopatologia , Recuperação de Função Fisiológica , Fluxo Sanguíneo Regional , Escleroderma Sistêmico/diagnóstico , Escleroderma Sistêmico/fisiopatologia , Úlcera Cutânea/diagnóstico , Úlcera Cutânea/fisiopatologia , Fatores de Tempo , Resultado do Tratamento
20.
Psychol Med ; 47(6): 1062-1084, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27974062

RESUMO

BACKGROUND: Job loss, debt and financial difficulties are associated with increased risk of mental illness and suicide in the general population. Interventions targeting people in debt or unemployed might help reduce these effects. METHOD: We searched MEDLINE, Embase, The Cochrane Library, Web of Science, and PsycINFO (January 2016) for randomized controlled trials (RCTs) of interventions to reduce the effects of unemployment and debt on mental health in general population samples. We assessed papers for inclusion, extracted data and assessed risk of bias. RESULTS: Eleven RCTs (n = 5303 participants) met the inclusion criteria. All recruited participants were unemployed. Five RCTs assessed 'job-club' interventions, two cognitive behaviour therapy (CBT) and a single RCT assessed each of emotional competency training, expressive writing, guided imagery and debt advice. All studies were at high risk of bias. 'Job club' interventions led to improvements in levels of depression up to 2 years post-intervention; effects were strongest among those at increased risk of depression (improvements of up to 0.2-0.3 s.d. in depression scores). There was mixed evidence for effectiveness of group CBT on symptoms of depression. An RCT of debt advice found no effect but had poor uptake. Single trials of three other interventions showed no evidence of benefit. CONCLUSIONS: 'Job-club' interventions may be effective in reducing depressive symptoms in unemployed people, particularly those at high risk of depression. Evidence for CBT-type interventions is mixed; further trials are needed. However the studies are old and at high risk of bias. Future intervention studies should follow CONSORT guidelines and address issues of poor uptake.


Assuntos
Transtorno Depressivo/prevenção & controle , Pobreza , Desemprego , Humanos
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