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1.
Nat Commun ; 14(1): 2088, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37045846

RESUMO

Kinetic Alfvén waves (KAWs) are ubiquitous throughout the plasma universe. Although they are broadly believed to provide a potential approach for energy exchange between electromagnetic fields and plasma particles, neither the detail nor the efficiency of the interactions has been well-determined yet. The primary difficulty has been the paucity of knowledge of KAWs' spatial structure in observation. Here, we apply a particle-sounding technique to Magnetospheric Multiscale mission data to quantitatively determine the perpendicular wavelength of KAWs from ion gyrophase-distribution observations. Our results show that KAWs' perpendicular wavelength is statistically 2.4[Formula: see text] times proton thermal gyro-radius. This observation yields an upper bound of the energy the majority proton population can reach in coherent interactions with KAWs, that is, roughly 5.76 times proton perpendicular thermal energy. Therefore, the method and results shown here provide a basis for unraveling the effects of KAWs in dissipating energy and accelerating particles in a number of astrophysical systems, e.g., planetary magnetosphere, astrophysical shocks, stellar corona and wind, and the interstellar medium.

2.
AIDS ; 37(2): 333-339, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36541644

RESUMO

BACKGROUND: HIV drug resistance (HIVDR) surveillance is an important tool to monitor threats to progress towards epidemic control. The characterization of HIVDR in Nigeria at the national level is needed to inform both clinical decisions and population-level HIV policy strategies. This study uses data obtained from the Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS) to describe the prevalence and distribution of HIVDR in Nigeria. METHODS: NAIIS was a cross-sectional, population-based survey of households throughout Nigeria in 2018. NAIIS was designed to provide estimates of HIV prevalence and related health indicators from a nationally representative sample. The study population included participants aged 15-64 years who tested positive for HIV, had a viral load at least 1000 copies/ml, and had available HIV drug resistance genotypes. HIV isolates were genotyped to detect drug resistance mutations. Individual characteristics of study participants associated with HIVDR were identified using a weighted multivariable logistic regression model. RESULTS: Of 1355 respondents with available HIV genotypes, 293 (19%) had evidence of drug-resistant mutations (DRMs) that conferred resistance to at least one antiretroviral drug. The majority of DRMs observed conferred resistance to NNRTIs (17.6%) and NRTIs (11.2%). HIVDR was associated with being ART-experienced, longer duration on ART, and lower CD4+ count but not sociodemographic characteristics. CONCLUSION: The population level DRM prevalence in Nigeria was consistent with what would be expected in a mature HIV treatment landscape. The continued roll out of dolutegravir-anchored regimens should mitigate the impact of NNRTI resistance on population viral load suppression and progress towards epidemic control.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , HIV-1 , Humanos , Adulto , Fármacos Anti-HIV/uso terapêutico , Fármacos Anti-HIV/farmacologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Carga Viral , Estudos Transversais , Prevalência , Nigéria/epidemiologia , Farmacorresistência Viral/genética , Mutação
3.
Nat Commun ; 13(1): 5593, 2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36151097

RESUMO

Identifying how energy transfer proceeds from macroscales down to microscales in collisionless plasmas is at the forefront of astrophysics and space physics. It provides information on the evolution of involved plasma systems and the generation of high-energy particles in the universe. Here we report two cross-scale energy-transfer events observed by NASA's Magnetospheric Multiscale spacecraft in Earth's magnetosphere. In these events, hot ions simultaneously undergo interactions with macroscale (~[Formula: see text] km) ultra-low-frequency waves and microscale ([Formula: see text] km) electromagnetic-ion-cyclotron (EMIC) waves. The cross-scale interactions cause energy to directly transfer from macroscales to microscales, and finally dissipate at microscales via EMIC-wave-induced ion energization. The direct measurements of the energy transfer rate in the second event confirm the efficiency of this cross-scale transfer process, whose timescale is estimated to be roughly ten EMIC-wave periods about (1 min). Therefore, these observations experimentally demonstrate that simultaneous macroscale and microscale wave-ion interactions provide an efficient mechanism for cross-scale energy transfer and plasma energization in astrophysical and space plasmas.

4.
Nat Commun ; 13(1): 924, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35177615

RESUMO

The magnetic gradient and curvature drift of energetic ions can form a longitudinal electric current around a planet known as the ring current, that has been observed in the intrinsic magnetospheres of Earth, Jupiter, and Saturn. However, there is still a lack of observational evidence of ring current in Mercury's magnetosphere, which has a significantly weaker dipole magnetic field. Under such conditions, charged particles are thought to be efficiently lost through magnetopause shadowing and/or directly impact the planetary surface. Here, we present the observational evidence of Mercury's ring current by analysing particle measurements from MErcury Surface, Space Environment, GEochemistry, and Ranging (MESSENGER) spacecraft. The ring current is bifurcated because of the dayside off-equatorial magnetic minima. Test-particle simulation with Mercury's dynamic magnetospheric magnetic field model (KT17 model) validates this morphology. The ring current energy exceeds [Formula: see text] J during active times, indicating that magnetic storms may also occur on Mercury.

5.
Phys Rev Lett ; 127(3): 031102, 2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34328784

RESUMO

We report observations of gamma-ray emissions with energies in the 100-TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1, with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources.

6.
Phys Rev Lett ; 126(14): 141101, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33891464

RESUMO

We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and compatible with expectations from the hadronic emission scenario in which gamma rays originate from the decay of π^{0}'s produced through the interaction of protons with the interstellar medium in the Galaxy. This is strong evidence that cosmic rays are accelerated beyond PeV energies in our Galaxy and spread over the Galactic disk.

7.
Lancet Microbe ; 2(7): e320-e330, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35252901

RESUMO

BACKGROUND: Drug resistance threatens global tuberculosis control. We aimed to examine mortality in patients with tuberculosis from high-burden countries, according to concordance or discordance of results from drug susceptibility testing done locally and whole-genome sequencing (WGS). METHODS: In this multicentre cohort study, we collected pulmonary Mycobacterium tuberculosis isolates and clinical data from individuals with tuberculosis from antiretroviral therapy programmes and tuberculosis clinics in Côte d'Ivoire, Democratic Republic of the Congo, Kenya, Nigeria, Peru, South Africa, and Thailand, stratified by HIV status and drug resistance. Sites tested drug susceptibility using routinely available methods. WGS was done on Illumina HiSeq 2500 in the USA and Switzerland, and TBprofiler was used to analyse the genomes. We included individuals aged 16 years or older with pulmonary tuberculosis (bacteriologically confirmed or clinically diagnosed). We analysed mortality in multivariable logistic regression models adjusted for sex, age, HIV status, history of tuberculosis, and sputum positivity. FINDINGS: Between Sept 1, 2014, and July 4, 2016, of 634 patients included in our previous analysis, we included 582 patients with tuberculosis (median age 33 years [IQR 27-43], 225 [39%] women, and 247 [42%] HIV-positive). Based on WGS, 339 (58%) isolates were pan-susceptible, 35 (6%) monoresistant, 146 (25%) multidrug-resistant, and 24 (4%) pre-extensively drug-resistant (pre-XDR) or XDR. The analysis of mortality was based on 530 patients; 63 (12%) died and 77 (15%) patients received inappropriate treatment. Mortality ranged from 6% (18 of 310) in patients with pan-susceptible tuberculosis to 39% (nine of 23) in patients with pre-XDR or XDR tuberculosis. The adjusted odds ratio for mortality was 4·92 (95% CI 2·47-9·78) among undertreated patients, compared with appropriately treated patients. INTERPRETATION: In seven countries with a high burden of tuberculosis, we observed discrepancies between drug resistance patterns obtained locally and WGS. The underdiagnosis of drug resistance resulted in inappropriate treatment and higher mortality. WGS can provide accurate and detailed drug resistance information required to improve the outcomes of drug-resistant tuberculosis in high-burden settings. Our results support WHO's call for point-of-care tests based on WGS. FUNDING: National Institutes of Allergy and Infectious Diseases, Swiss National Science Foundation, and Swiss National Center for Mycobacteria.


Assuntos
Infecções por HIV , Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose Pulmonar , Tuberculose , Adulto , Antituberculosos/farmacologia , Estudos de Coortes , Feminino , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/genética , Tuberculose/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Pulmonar/tratamento farmacológico
8.
Curr Pharm Des ; 27(23): 2737-2745, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33059563

RESUMO

BACKGROUND AND AIMS: Alcohol use disorders (AUD) are among the most prevalent mental disorders around the world, yet still remain the most undertreated. Many studies report the low rate of treatment uptake, less than 20%, among people with AUD. Among those accessing care, a large majority only approach their GP for help. Therefore, primary care is a strategic setting for the identification and the management of AUD. International recommendations stress AUD pharmacotherapy for withdrawal and craving management, but very few studies have shown interest in the management of AUDs in primary care. The main objective of this study was to analyse pharmacotherapy in AUD management in primary care by means of a systematic literature review. METHODS: A systematic literature review (PRISMA) was carried out. 5 databases were screened: PUBMED via MEDLINE, LiSSa, the SUDOC catalogue, PASCAL and EMBASE. Search algorithms were used integrating the concepts of pharmacotherapy management, alcohol use disorders and primary care, only in the English language. RESULTS: 296 studies were selected and 10 were included. One was a follow-up study on the national prescription database, while four were cross-sectional studies with an auto-questionnaire survey. Of the 10 studies included, two were conducted in Europe, five in North America, two in Australia and one in South Africa. These pharmacotherapy studies were concerned with the anti-craving treatment, and 3 types of medications were used: Disulfiram, Acamprosate and Naltrexone. Factors identified as limiting or facilitating prescriptions concerned cost, indications, efficacy, training and adjuncts to pharmacotherapy. CONCLUSION: Knowledge and prescription of pharmacotherapy for AUD, more specifically, anti-craving treatment, is insufficient in primary care. There is a lack of data and studies on the efficacy of anti-craving treatment in primary care. Guidelines for AUD management, including psychological and medical management and pharmacotherapy, do exist but have not been adapted to primary care practice. Barriers and facilitators of pharmacotherapy prescription in AUD in primary care were identified in this study.


Assuntos
Alcoolismo , Alcoolismo/tratamento farmacológico , Estudos Transversais , Dissulfiram/uso terapêutico , Medicina de Família e Comunidade , Seguimentos , Humanos
9.
Thromb Update ; 5: 100086, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38620810

RESUMO

Since the beginning of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2) virus pandemic, several highly effective and safe vaccines have been produced at remarkable speed. Following global implementation of vaccination programmes, cases of thrombosis with thrombocytopenia following administration of adenoviral vector-based vaccines started being reported. In this review we discuss the known pathogenesis and epidemiology of so-called vaccine induced thrombocytopenia and thrombosis (VITT). We consider the available guidelines, diagnostic laboratory tests and management options for these patients. Finally, we discuss important unanswered questions and areas for future research in this novel pathoclinical entity.

10.
J Geophys Res Space Phys ; 125(7): e2019JA027410, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32999805

RESUMO

The Vlasiator hybrid-Vlasov code was developed to investigate global magnetospheric dynamics at ion-kinetic scales. Here we focus on the role of magnetic reconnection in the formation and evolution of magnetic islands at the low-latitude magnetopause, under southward interplanetary magnetic field conditions. The simulation results indicate that (1) the magnetic reconnection ion kinetics, including the Earthward pointing Larmor electric field on the magnetospheric side of an X-point and anisotropic ion distributions, are well-captured by Vlasiator, thus enabling the study of reconnection-driven magnetic island evolution processes, (2) magnetic islands evolve due to continuous reconnection at adjacent X-points, "coalescence" which refers to the merging of neighboring islands to create a larger island, "erosion" during which an island loses magnetic flux due to reconnection, and "division" which involves the splitting of an island into smaller islands, and (3) continuous reconnection at adjacent X-points is the dominant source of magnetic flux and plasma to the outer layers of magnetic islands resulting in cross-sectional growth rates up to + 0.3 RE 2/min. The simulation results are compared to the Magnetospheric Multiscale (MMS) measurements of a chain of ion-scale flux transfer events (FTEs) sandwiched between two dominant X-lines. The MMS measurements similarly reveal (1) anisotropic ion populations and (2) normalized reconnection rate ~0.18, in agreement with theory and the Vlasiator predictions. Based on the simulation results and the MMS measurements, it is estimated that the observed ion-scale FTEs may grow Earth-sized within ~10 min, which is comparable to the average transport time for FTEs formed in the subsolar region to the high-latitude magnetopause. Future simulations shall revisit reconnection-driven island evolution processes with improved spatial resolutions.

11.
Phys Rev Lett ; 123(5): 051101, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31491288

RESUMO

We report on the highest energy photons from the Crab Nebula observed by the Tibet air shower array with the underground water-Cherenkov-type muon detector array. Based on the criterion of a muon number measured in an air shower, we successfully suppress 99.92% of the cosmic-ray background events with energies E>100 TeV. As a result, we observed 24 photonlike events with E>100 TeV against 5.5 background events, which corresponds to a 5.6σ statistical significance. This is the first detection of photons with E>100 TeV from an astrophysical source.

12.
Afr J Lab Med ; 8(1): 722, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31534913

RESUMO

BACKGROUND: Genetic diversity is abundant on the African continent. However, genomic research has been hampered by a lack of high quality and extensively annotated biospecimens and the necessary infrastructure to support such a technology-intensive effort. OBJECTIVE: The Institute of Human Virology Nigeria (IHVN) partnered with the H3Africa Consortium and the Coriell Institute for Medical Research to build an internationally recognised biorepository for the receipt, processing, storage and distribution of biospecimens for biomedical research. Here, the authors describe the procedures, challenges and results encountered. RESULTS: Key requirements for a high-quality biorepository were identified: (1) institutional support of infrastructure and services, (2) on-site trained staff with primary commitment to the biorepository, (3) reliance on best practices from globally recognised biorepository groups, (4) early implementation of a quality management system, (5) adoption of a laboratory information management system with demonstrated versatility in functions, (6) collaboration with external experts and sharing of experience through abstracts, newsletters, published manuscripts, and attendance at meetings and workshops, (7) strict adherence to local and national ethical standards and (8) a sustainability plan that is reviewed and updated annually. CONCLUSION: Utilising published best practices of globally recognised experts in the biorepository field as a benchmark, IHVN expanded and reorganised its existing laboratory facility and staff to take on this new purpose.

13.
Nat Commun ; 10(1): 1040, 2019 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-30833556

RESUMO

Magnetic cavities (sometimes referred to as magnetic holes) at electron kinetic scale are thought to be one of the extremely small intermittent structures formed in magnetized turbulent plasmas, where the turbulence energy cascaded down to electron scale may finally be dissipated and consequently energize the electrons. However, the geometry and formation of these structures remain not definitively resolved. Here we discuss an electron scale magnetic cavity embedded in a proton scale magnetic cavity observed by the MMS spacecraft in the magnetosheath. By applying an innovative particle sounding technique, we directly depict the boundary of the electron scale magnetic cavity and uncover the geometry. We find that this structure is nearly circular with a radius of 10.0 km and its formation is due to the diamagnetic current. Investigation of the electron scale structure is only recently made possible by the high spatial and temporal resolution provided by MMS observations.

14.
Lancet Infect Dis ; 19(3): 298-307, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30744962

RESUMO

BACKGROUND: Drug resistance is a challenge for the global control of tuberculosis. We examined mortality in patients with tuberculosis from high-burden countries, according to concordance or discordance of results from drug susceptibility testing done locally and in a reference laboratory. METHODS: This multicentre cohort study was done in Côte d'Ivoire, Democratic Republic of the Congo, Kenya, Nigeria, South Africa, Peru, and Thailand. We collected Mycobacterium tuberculosis isolates and clinical data from adult patients aged 16 years or older. Patients were stratified by HIV status and tuberculosis drug resistance. Molecular or phenotypic drug susceptibility testing was done locally and at the Swiss National Center for Mycobacteria, Zurich, Switzerland. We examined mortality during treatment according to drug susceptibility test results and treatment adequacy in multivariable logistic regression models adjusting for sex, age, sputum microscopy, and HIV status. FINDINGS: We obtained M tuberculosis isolates from 871 patients diagnosed between 2013 and 2016. After exclusion of 237 patients, 634 patients with tuberculosis were included in this analysis; the median age was 33·2 years (IQR 26·9-42·5), 239 (38%) were women, 272 (43%) were HIV-positive, and 69 (11%) patients died. Based on the reference laboratory drug susceptibility test, 394 (62%) strains were pan-susceptible, 45 (7%) monoresistant, 163 (26%) multidrug-resistant (MDR), and 30 (5%) had pre-extensively or extensively drug resistant (pre-XDR or XDR) tuberculosis. Results of reference and local laboratories were concordant for 513 (81%) of 634 patients and discordant for 121 (19%) of 634. Overall, sensitivity to detect any resistance was 90·8% (95% CI 86·5-94·2) and specificity 84·3% (80·3-87·7). Mortality ranged from 6% (20 of 336) in patients with pan-susceptible tuberculosis treated according to WHO guidelines to 57% (eight of 14) in patients with resistant strains who were under-treated. In logistic regression models, compared with concordant drug susceptibility test results, the adjusted odds ratio of death was 7·33 (95% CI 2·70-19·95) for patients with discordant results potentially leading to under-treatment. INTERPRETATION: Inaccurate drug susceptibility testing by comparison with a reference standard leads to under-treatment of drug-resistant tuberculosis and increased mortality. Rapid molecular drug susceptibility test of first-line and second-line drugs at diagnosis is required to improve outcomes in patients with MDR tuberculosis and pre-XDR or XDR tuberculosis. FUNDING: National Institutes of Allergy and Infectious Diseases, Swiss National Science Foundation, Swiss National Center for Mycobacteria.


Assuntos
Erros de Diagnóstico , Farmacorresistência Bacteriana , Testes de Sensibilidade Microbiana/métodos , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose/tratamento farmacológico , Tuberculose/mortalidade , Adolescente , Adulto , África , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/isolamento & purificação , Peru , Sensibilidade e Especificidade , Análise de Sobrevida , Tailândia , Tuberculose/microbiologia , Adulto Jovem
15.
Phys Rev Lett ; 120(3): 031101, 2018 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-29400499

RESUMO

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21_{stat}±0.20_{syst} (1.62±0.15_{stat}±0.22_{syst}) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

16.
Phys Plasmas ; 25(3)2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32905417

RESUMO

In space plasma, various effects of magnetic reconnection and turbulence cause the electron motion to significantly deviate from their Larmor orbits. Collectively these orbits affect the electron velocity distribution function and lead to the appearance of the "non-gyrotropic" elements in the pressure tensor. Quantification of this effect has important applications in space and laboratory plasma, one of which is tracing the electron diffusion region (EDR) of magnetic reconnection in space observations. Three different measures of agyrotropy of pressure tensor have previously been proposed, namely, A∅ e , Dng and Q. The multitude of contradictory measures has caused confusion within the community. We revisit the problem by considering the basic properties an agyrotropy measure should have. We show that A∅ e , Dng and Q are all defined based on the sum of the principle minors (i.e. the rotation invariant I 2) of the pressure tensor. We discuss in detail the problems of I 2-based measures and explain why they may produce ambiguous and biased results. We introduce a new measure AG constructed based on the determinant of the pressure tensor (i.e. the rotation invariant I 3) which does not suffer from the problems of I 2-based measures. We compare AG with other measures in 2 and 3-dimension particle-in-cell magnetic reconnection simulations, and show that AG can effectively trace the EDR of reconnection in both Harris and force-free current sheets. On the other hand, A∅ e does not show prominent peaks in the EDR and part of the separatrix in the force-free reconnection simulations, demonstrating that A∅ e does not measure all the non-gyrotropic effects in this case, and is not suitable for studying magnetic reconnection in more general situations other than Harris sheet reconnection.

17.
Ir J Med Sci ; 187(2): 343-347, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29043543

RESUMO

OBJECTIVES: Splenic marginal zone lymphoma (SMZL) is a rare indolent B-cell lymphoma with variable prognosis. As a result, there is sparse knowledge on the role of splenectomy and best management approaches. We aim to explore management strategies and outcomes amongst the cohort of SMZL patients at our centre. METHOD: A retrospective review of all splenectomies performed at a tertiary referral unit over a 23-year period was assessed. Immunohistochemical and pathological results of splenic samples, bone marrow biopsies, and peripheral blood were compiled. Operative management, surgical, and survival outcomes were assessed. Prognostic stratifications were applied and survival rates were calculated. RESULTS: Eight cases of SMZL from a database of 693 splenectomies were identified. All patients had intermediate/high-risk disease. All patients underwent splenectomy with one patient receiving preoperative rituximab. All patients had progression-free survival and resolution of disease. CONCLUSION: Based on the data obtained, current practice requires defined guidelines and centralised care.


Assuntos
Linfoma de Zona Marginal Tipo Células B/cirurgia , Neoplasias Esplênicas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Linfoma de Zona Marginal Tipo Células B/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Neoplasias Esplênicas/patologia , Taxa de Sobrevida
18.
Geophys Res Lett ; 44(8): 3456-3464, 2017 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-28713180

RESUMO

We report global observations of high-m poloidal waves during the recovery phase of the 22 June 2015 magnetic storm from a constellation of widely spaced satellites of five missions including Magnetospheric Multiscale (MMS), Van Allen Probes, Time History of Events and Macroscale Interactions during Substorm (THEMIS), Cluster, and Geostationary Operational Environmental Satellites (GOES). The combined observations demonstrate the global spatial extent of storm time poloidal waves. MMS observations confirm high azimuthal wave numbers (m ~ 100). Mode identification indicates the waves are associated with the second harmonic of field line resonances. The wave frequencies exhibit a decreasing trend as L increases, distinguishing them from the single-frequency global poloidal modes normally observed during quiet times. Detailed examination of the instantaneous frequency reveals discrete spatial structures with step-like frequency changes along L. Each discrete L shell has a steady wave frequency and spans about 1 RE , suggesting that there exist a discrete number of drift-bounce resonance regions across L shells during storm times.

19.
Science ; 356(6341): 960-963, 2017 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-28572393

RESUMO

The magnetopause deflects the solar wind plasma and confines Earth's magnetic field. We combine measurements made by the four spacecraft of the Magnetospheric Multiscale mission to demonstrate how the plasma and magnetic forces at the boundary affect the interaction between the shocked solar wind and Earth's magnetosphere. We compare these forces with the plasma pressure and examine the electron distribution function. We find that the magnetopause has sublayers with thickness comparable to the ion scale. Small pockets of low magnetic field strength, small radius of curvature, and high electric current mark the electron diffusion region. The flow of electrons, parallel and antiparallel to the magnetic field, reveals a complex topology with the creation of magnetic ropes at the boundary.

20.
Mucosal Immunol ; 10(5): 1335-1350, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28176789

RESUMO

The host immune status is critical for preventing opportunistic infections with Candida albicans. Whether the natural fungal diversity that exists between C. albicans isolates also influences disease development remains unclear. Here, we used an experimental model of oral infection to probe the host response to diverse C. albicans isolates in vivo and found dramatic differences in their ability to persist in the oral mucosa, which inversely correlated with the degree and kinetics of immune activation in the host. Strikingly, the requirement of interleukin (IL)-17 signaling for fungal control was conserved between isolates, including isolates with delayed induction of IL-17. This underscores the relevance of IL-17 immunity in mucosal defense against C. albicans. In contrast, the accumulation of neutrophils and induction of inflammation in the infected tissue was strictly strain dependent. The dichotomy of the inflammatory neutrophil response was linked to the capacity of fungal strains to cause cellular damage and release of alarmins from the epithelium. The epithelium thus translates differences in the fungus into qualitatively distinct host responses. Altogether, this study provides a comprehensive understanding of the antifungal response in the oral mucosa and demonstrates the relevance of evaluating intraspecies differences for the outcome of fungal-host interactions in vivo.


Assuntos
Alarminas/imunologia , Proteínas de Bactérias/imunologia , Candida albicans/fisiologia , Candidíase/microbiologia , Queratinócitos/fisiologia , Mucosa Bucal/imunologia , Neutrófilos/imunologia , Biodiversidade , Candida albicans/patogenicidade , Linhagem Celular , Movimento Celular , Interações Hospedeiro-Patógeno , Humanos , Imunidade nas Mucosas , Interleucina-17/metabolismo , Queratinócitos/microbiologia , Mucosa Bucal/microbiologia , Transdução de Sinais , Especificidade da Espécie , Simbiose , Virulência
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