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1.
ESMO Open ; 7(6): 100605, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36356412

RESUMO

BACKGROUND: Continued smoking after a diagnosis of cancer negatively impacts cancer outcomes, but the impact of tobacco on newer treatments options is not well established. Collecting and evaluating tobacco use in clinical trials may advance understanding of the consequences of tobacco use on treatment modalities, but little is known about the frequency of reporting and analysis of tobacco use in cancer cooperative clinical trial groups. PATIENTS AND METHODS: A comprehensive literature search was conducted to identify cancer cooperative group clinical trials published from January 2017-October 2019. Eligible studies evaluated either systemic and/or radiation therapies, included ≥100 adult patients, and reported on at least one of: overall survival, disease/progression-free survival, response rates, toxicities/adverse events, or quality-of-life. RESULTS: A total of 91 studies representing 90 trials met inclusion criteria with trial start dates ranging from 1995 to 2015 with 14% involving lung and 5% head and neck cancer patients. A total of 19 studies reported baseline tobacco use; 2 reported collecting follow-up tobacco use. Seven studies reported analysis of the impact of baseline tobacco use on clinical outcomes. There was significant heterogeneity in the reporting of baseline tobacco use: 7 reported never/ever status, 10 reported never/ex-smoker/current smoker status, and 4 reported measuring smoking intensity. None reported verifying smoking status or second-hand smoke exposure. Trials of lung and head and neck cancers were more likely to report baseline tobacco use than other disease sites (83% versus 6%, P < 0.001). CONCLUSIONS: Few cancer cooperative group clinical trials report and analyze trial participants' tobacco use. Significant heterogeneity exists in reporting tobacco use. Routine standardized collection and reporting of tobacco use at baseline and follow-up in clinical trials should be implemented to enable investigators to evaluate the impact of tobacco use on new cancer therapies.


Assuntos
Neoplasias , Nicotiana , Adulto , Humanos , Nicotiana/efeitos adversos , Uso de Tabaco/efeitos adversos , Uso de Tabaco/epidemiologia , Neoplasias/epidemiologia , Neoplasias/etiologia , Neoplasias/terapia
2.
Opt Express ; 30(15): 26955-26966, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-36236877

RESUMO

A conceptually new approach to synchronizing accelerator-based light sources and external laser systems is presented. The concept is based on utilizing a sufficiently intense accelerator-based single-cycle terahertz pulse to slice a thereby intrinsically synchronized femtosecond-level part of a longer picosecond laser pulse in an electro-optic crystal. A precise synchronization of the order of 10 fs is demonstrated, allowing for real-time lock-in amplifier signal demodulation. We demonstrate successful operation of the concept with three benchmark experiments using a 4th generation accelerator-based terahertz light source, i.e. (i) far-field terahertz time-domain spectroscopy, (ii) terahertz high harmonic generation spectroscopy, and (iii) terahertz scattering-type scanning near-field optical microscopy.

3.
Ann Oncol ; 32(12): 1552-1570, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34509615

RESUMO

BACKGROUND: Telemedicine services have been increasingly used to facilitate post-treatment cancer survivorship care, including improving access; monitoring health status, health behaviors, and symptom management; enhancing information exchange; and mitigating the costs of care delivery, especially since the COVID-19 pandemic. To inform guidance for the use of telemedicine in the post-COVID era, the aim of this overview of systematic reviews (SRs) was to evaluate the efficacy of, and survivor engagement in, telemedicine interventions in the post-treatment survivorship phase, and to consider implementation barriers and facilitators. METHODS: PubMed, Cochrane CENTRAL, CINAHL, Embase, and Web of Science databases were searched. SRs that examined the use of telemedicine in the post-treatment phase of cancer survivorship, published between January 2010 and April 2021, were included. Efficacy data were synthesized narratively. Implementation barriers and facilitators were synthesized using the Consolidated Framework for Implementation Research. RESULTS: Twenty-nine SRs were included. A substantive body of evidence found telemedicine to benefit the management of psychosocial and physical effects, particularly for improving fatigue and cognitive function. There was a lack of evidence on the use of telemedicine in the prevention and surveillance for recurrences and new cancers as well as management of chronic medical conditions. This overview highlights a range of diverse barriers and facilitators at the patient, health service, and system levels. CONCLUSIONS: This review highlights the benefits of telemedicine in addressing psychosocial and physical effects, but not in other areas of post-treatment cancer survivorship care. This large review provides practical guidance for use of telemedicine in post-treatment survivorship care.


Assuntos
COVID-19 , Neoplasias , Telemedicina , Humanos , Neoplasias/terapia , Pandemias , SARS-CoV-2 , Sobrevivência , Revisões Sistemáticas como Assunto
4.
J Hosp Infect ; 113: 44-51, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33775742

RESUMO

BACKGROUND: Little is known about Clostridioides difficile infection (CDI) in patients with cystic fibrosis (CF). The aim of this study was to investigate the prevalence, molecular epidemiology and risk factors for CDI in asymptomatic and symptomatic adults with CF in Western Australia. METHODS: Faecal samples from symptomatic and asymptomatic patients were prospectively collected and tested for the presence of C. difficile by toxigenic culture. Ribotyping was performed by established protocols. Logistic regression analysis was performed to analyse the risk factors for C. difficile colonization and infection. Extensive environmental sampling was performed within the CF clinic in Perth. RESULTS: The prevalence rates of asymptomatic toxigenic and non-toxigenic C. difficile colonization were 30% (14/46 patients) and 24% (11/46 patients), respectively. Fifteen ribotypes (RTs) of C. difficile were identified, of which non-toxigenic RT 039 was the most common. Among the symptomatic patients, the prevalence of toxigenic CDI was 33% (11/33 patients). Impaired glucose tolerance/diabetes mellitus and duration of intravenous antibiotic use in the past 12 months were significantly associated with increased risk of asymptomatic toxigenic C. difficile carriage and CDI. A trend towards higher CF transmembrane conductance regulator modulator treatment was observed in the CDI group. Extensive environmental sampling showed no evidence of toxigenic C. difficile contamination within the CF clinic. CONCLUSIONS: A high prevalence of asymptomatic carriage of toxigenic C. difficile was observed in adults with CF, comparable with that observed in the symptomatic CF population. There was no evidence of direct person-to-person transmission.


Assuntos
Clostridioides difficile , Infecções por Clostridium , Fibrose Cística , Adulto , Austrália/epidemiologia , Clostridioides , Clostridioides difficile/genética , Infecções por Clostridium/epidemiologia , Fibrose Cística/complicações , Fibrose Cística/epidemiologia , Humanos
6.
Curr Oncol ; 26(6): 361-368, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31896934

RESUMO

Background: Quitting smoking after a cancer diagnosis maximizes treatment-related effects, improves prognosis, and enhances quality of life. However, smoking cessation (sc) services are not routinely integrated into cancer care. The Princess Margaret Cancer Centre implemented a digitally-based sc program in oncology, leveraging an e-referral system (cease) to screen all new ambulatory patients, provide tailored education and advice on quitting, and facilitate referrals. Methods: We adopted the Framework for Managing eHealth Change to guide implementation of the sc program by integrating 6 key elements: governance and leadership, stakeholder engagement, communication, workflow analysis and integration, monitoring and evaluation, and training and education. Results: Incorporating elements of the Framework, we used extensive stakeholder engagement and strategic partnerships to establish a sc program with organizational and provincial accountability. Existing electronic patient-reported assessments were changed to integrate cease. Clinic audits and staff engagement allowed for analysis of workflow, ongoing monitoring and evaluation that aided in establishing a communication strategy, and development of cancer-specific education for patients and health care providers. From April 2016 to March 2018, 22,137 new patients were eligible for screening. Among those new patients, 13,617 (62%) were screened, with 1382 (10%) being current smokers and 532 (4%) having recently quit (within 6 months). Of the current smokers and those who had recently quit, all were advised to quit or to stay smoke-free, and 380 (20%) accepted referral to a sc counselling service. Conclusions: Here, we provide a comprehensive practice blueprint for the implementation of digitally based sc programs as a standard of care within comprehensive cancer centres with high patient volumes.


Assuntos
Institutos de Câncer/organização & administração , Neoplasias , Desenvolvimento de Programas , Abandono do Hábito de Fumar/métodos , Comunicação , Humanos , Programas de Rastreamento , Guias de Prática Clínica como Assunto , Participação dos Interessados , Ensino , Fluxo de Trabalho
7.
Curr Oncol ; 26(6): e733-e741, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31896943

RESUMO

Background: We assessed whether the presence and severity of common cancer symptoms are associated with the health utility score (hus) generated from the EQ-5D (EuroQol Research Foundation, Rotterdam, Netherlands) in patients with cancer and evaluated whether it is possible pragmatically to integrate routine hus and symptom evaluation in our cancer population. Methods: Adult outpatients at Princess Margaret Cancer Centre with any cancer were surveyed cross-sectionally using the Edmonton Symptom Assessment System (esas) and the EQ-5D-3L, and results were compared using Spearman correlation coefficients and regression analyses. Results: Of 764 patients analyzed, 27% had incurable disease. We observed mild-to-moderate correlations between each esas symptom score and the hus (Spearman coefficients: -0.204 to -0.416; p < 0.0001 for each comparison), with the strongest associations being those for pain (R = -0.416), tiredness (R = -0.387), and depression (R =-0.354). Multivariable analyses identified pain and depression as highly associated (both p < 0.0001) and tiredness as associated (p = 0.03) with the hus. The ability of the esas to predict the hus was low, at 0.25. However, by mapping esas pain, anxiety, and depression scores to the corresponding EQ-5D questions, we could derive the hus using partial esas data, with Spearman correlations of 0.83-0.91 in comparisons with direct EQ-5D measurement of the hus. Conclusions: The hus derived from the EQ-5D-3L is associated with all major cancer symptoms as captured by the esas. The esas scores alone could not predict EQ-5D scores with high accuracy. However, esas-derived questions assessing the same domains as the EQ-5D-3L questions could be mapped to their corresponding EQ-5D questions to generate the hus, with high correlation to the directly measured hus. That finding suggests a potential approach to integrating routine symptom and hus evaluations after confirmatory studies.


Assuntos
Neoplasias , Qualidade de Vida , Avaliação de Sintomas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Ansiedade , Depressão , Fadiga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dor , Medidas de Resultados Relatados pelo Paciente , Inquéritos e Questionários , Adulto Jovem
8.
Dis Esophagus ; 31(12)2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29905764

RESUMO

Esophageal cancer and its treatment can cause serious morbidity/toxicity. These effects on health-related quality of life (HRQOL) can be measured using disease-specific scales such as FACT-E, generic scales such as EQ-5D-3L, or through symptoms. In a two-year cross-sectional study, we compared HRQOL across esophageal cancer patients treated in an ambulatory clinic and across multiple disease states, among patients with all stages of esophageal cancer. Consenting patients completed FACT-E, EQ-5D, a visual analog scale, and patient reported (PR)-ECOG. Symptom complexes were constructed from FACT-E domains. Responses were categorized by disease state: pre-, during, and post-treatment, surveillance, progression, and palliative chemotherapy. Spearman correlation and multivariable linear regression characterized these associations. In total, 199 patients completed 317 questionnaires. Mean FACT-E and subscale scores dropped from baseline through treatment and recovered during post-treatment surveillance (P < 0.001); EQ-5D health utility scores (HUS) displayed a similar pattern but with smaller differences (P = 0.07), and with evidence of ceiling effect. Among patients with stage II/III esophageal cancer, mean EQ-5D HUS varied across disease states (P < 0.001), along with FACT-E and subscales (P < 0.001). Among patients with advanced disease, there was no significant difference between baseline and on-treatment total scores, but improved esophageal cancer-specific scales were noted (P = 0.003). Strong correlation was observed between EQ-5D and FACT-E (R = 0.73), along with physical and functional subscales. In addition, the association between FACT-E and EQ-5D HUS was maintained in a multivariable model (P < 0.001). We interpret these results to suggest that in a real-world clinic setting, FACT-E, EQ-5D HUS, and symptoms were strongly correlated. Most HRQOL and symptom parameters suggested that patients had worse HRQOL and symptoms during curative therapy, but recovered well afterwards. In contrast, palliative chemotherapy had a neutral to positive impact on HRQOL/symptoms when compared to their baseline pre-treatment state.


Assuntos
Neoplasias Esofágicas/diagnóstico , Nível de Saúde , Qualidade de Vida , Índice de Gravidade de Doença , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estatísticas não Paramétricas , Inquéritos e Questionários
9.
Nanoscale ; 9(30): 10933-10939, 2017 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-28731095

RESUMO

Conducting domain walls (CDWs) in ferroelectric materials are promising candidates for applications in a manifold of nanoscale, optoelectronic devices. Characterization of their microscopic properties, however, remains challenging due to their small dimension and highly insulating environment. Here, we inspect individual CDWs in single-crystalline LiNbO3 by the combination of photoemission electron microscopy (PEEM) and second harmonic generation (SHG) microscopy. While SHG unveils the overall domain wall inclination angle α, PEEM is sensitive to local conductance variations, both at and away from the domain wall. Thus, the two imaging techniques deliver complementary information over a large field of view. In agreement with earlier theoretical predictions we find that the local conductance is dictated by α and reveal a quantitative connection between them. Our results help to elucidate the electronic structure of CDWs and underline the value of PEEM as a non-contact characterization tool for mapping local conductance variations in highly resistive environments.

10.
Nano Lett ; 16(5): 3285-91, 2016 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-27070961

RESUMO

Magnetic skyrmions in chiral magnets are nanoscale, topologically protected magnetization swirls that are promising candidates for spintronics memory carriers. Therefore, observing and manipulating the skyrmion state on the surface level of the materials are of great importance for future applications. Here, we report a controlled way of creating a multidomain skyrmion state near the surface of a Cu2OSeO3 single crystal, observed by soft resonant elastic X-ray scattering. This technique is an ideal tool to probe the magnetic order at the L3 edge of 3d metal compounds giving an average depth sensitivity of ∼50 nm. The single-domain 6-fold-symmetric skyrmion lattice can be broken up into domains, overcoming the propagation directions imposed by the cubic anisotropy by applying the magnetic field in directions deviating from the major cubic axes. Our findings open the door to a new way to manipulate and engineer the skyrmion state locally on the surface or on the level of individual skyrmions, which will enable applications in the future.

11.
Curr Oncol ; 23(6): e546-e555, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28050143

RESUMO

PURPOSE: Smoking cessation and increased physical activity (pa) have been linked to better outcomes in cancer survivors. We assessed whether socioeconomic factors influence changes in those behaviours after a cancer diagnosis. METHODS: As part of a cross-sectional study, a diverse group of cancer survivors at the Princess Margaret Cancer Centre (Toronto, ON), completed a questionnaire about past and current lifestyle behaviours and perceptions about the importance of those behaviours with respect to their health. The influence of socioeconomic indicators on smoking status and physical inactivity at 1 year before and after diagnosis were assessed using multivariable logistic regression with adjustment for clinico-demographic factors. RESULTS: Of 1222 participants, 1192 completed the smoking component. Of those respondents, 15% smoked before diagnosis, and 43% of those smokers continued to smoke after. The proportion of survivors who continued to smoke increased with lower education level (p = 0.03). Of the 1106 participants answering pa questions, 39% reported being physically inactive before diagnosis, of whom 82% remained inactive afterward. Survivors with a lower education level were most likely to remain inactive after diagnosis (p = 0.003). Lower education level, household income, and occupation were associated with the perception that pa had no effect or could worsen fatigue and quality of life (p ≤ 0.0001). CONCLUSIONS: In cancer survivors, education level was a major modifier of smoking and pa behaviours. Lower socioeconomic status was associated with incorrect perceptions about pa. Targeting at-risk survivors by education level should be evaluated as a strategy in cancer survivorship programs.

12.
J Clin Pharm Ther ; 40(6): 635-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26365492

RESUMO

WHAT IS KNOWN AND OBJECTIVE: The dofetilide label recommends using actual body weight (ABW) to calculate the Cockcroft-Gault creatinine clearance (CrCl) for the determination of the initial dose; however, few studies have attempted to evaluate this dosing recommendation in overweight and obese patients. We evaluated whether the current dofetilide dosing recommendation based on ABW is appropriate in overweight and obese patients. METHODS: This is a retrospective cohort study conducted at two large academic medical centres in the United States on overweight and obese patients (body mass index ≥ 25 kg/m(2)) who were newly started on dofetilide based on ABW. Patients were categorized into (i) the different-dose group if their CrCl calculated based on the ideal body weight (IBW) resulted in a lower initial dofetilide dose compared with ABW-based CrCl and (ii) the same-dose group if they would have the same initial dose based on IBW and ABW. The primary outcome was dofetilide dose reduction or discontinuation due to prolongation of the corrected QT interval during the first 3 days of dofetilide therapy. Multivariable logistic regression analysis was performed to identify factors predicting the risk of primary outcome. RESULTS AND DISCUSSION: Of the 132 patients included in the study, 29 (22·0%) were in the different-dose group and 40 (30·3%) had the primary outcome. The per cent of patients with the primary outcome was not statistically significantly different between the different-dose and same-dose groups (37·9% vs. 28·2%; P = 0·31). Diabetes mellitus was a significant predictor for the primary outcome (odds ratio 2·54; 95% confidence interval 1·05-6·15). WHAT IS NEW AND CONCLUSION: Our study provides the evidence on the safety of the current dofetilide dosing recommendation in overweight and obese populations in clinical practice. Current ABW-based dofetilide dosing is reasonable in overweight and obese patients.


Assuntos
Peso Corporal/fisiologia , Obesidade/fisiopatologia , Sobrepeso/fisiopatologia , Fenetilaminas/administração & dosagem , Sulfonamidas/administração & dosagem , Adulto , Idoso , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
13.
Nat Mater ; 14(11): 1116-22, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26343913

RESUMO

Following the early prediction of the skyrmion lattice (SkL)--a periodic array of spin vortices--it has been observed recently in various magnetic crystals mostly with chiral structure. Although non-chiral but polar crystals with Cnv symmetry were identified as ideal SkL hosts in pioneering theoretical studies, this archetype of SkL has remained experimentally unexplored. Here, we report the discovery of a SkL in the polar magnetic semiconductor GaV4S8 with rhombohedral (C3v) symmetry and easy axis anisotropy. The SkL exists over an unusually broad temperature range compared with other bulk crystals and the orientation of the vortices is not controlled by the external magnetic field, but instead confined to the magnetic easy axis. Supporting theory attributes these unique features to a new Néel-type of SkL describable as a superposition of spin cycloids in contrast to the Bloch-type SkL in chiral magnets described in terms of spin helices.

14.
Sci Rep ; 5: 12582, 2015 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-26215769

RESUMO

Recently, the fundamental and nanoscale understanding of complex phenomena in materials research and the life sciences, witnessed considerable progress. However, elucidating the underlying mechanisms, governed by entangled degrees of freedom such as lattice, spin, orbit, and charge for solids or conformation, electric potentials, and ligands for proteins, has remained challenging. Techniques that allow for distinguishing between different contributions to these processes are hence urgently required. In this paper we demonstrate the application of scattering-type scanning near-field optical microscopy (s-SNOM) as a novel type of nano-probe for tracking transient states of matter. We introduce a sideband-demodulation technique that allows for probing exclusively the stimuli-induced change of near-field optical properties. We exemplify this development by inspecting the decay of an electron-hole plasma generated in SiGe thin films through near-infrared laser pulses. Our approach can universally be applied to optically track ultrafast/-slow processes over the whole spectral range from UV to THz frequencies.

15.
J Phys Condens Matter ; 27(2): 025503, 2015 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-25531984

RESUMO

La0.7Ce0.3MnO3 thin films of different thicknesses, degrees of CeO2-phase segregation and oxygen deficiency, grown on SrTiO3 single crystal substrates, were comparatively investigated with respect to both their spectral and temperature-dependent photoconductivity (PC) and their magnetoresistance (MR) behaviour under photoexcitation. While as-grown films were insensitive to optical excitation, oxygen reduction appeared to be an effective way to decrease the film resistance, but the film thickness was found to play a minor role. However, from the evaluation of the spectral behaviour of the PC and the comparison of the MR of the LCeMO/substrate-samples with a bare substrate under illumination we find that the photoconductivity data reflects not only contributions from (i) photogenerated charge carriers in the film and (ii) carriers injected from the photoconductive substrate (as concluded from earlier works), but also (iii) a decisive parallel photoconduction in the SrTiO3 substrate. Furthermore--also by analyzing the MR characteristics--the unexpected occurence of a strong electroresistive effect in the sample with the highest degree of CeO2 segregation and oxygen deficiency could be attributed to the electroresistance of the SrTiO3 substrate as well. The results suggest a critical reconsideration and possibly a reinterpretation of several previous photoconductivity and electroresistance investigations of manganite thin films on SrTiO3.

16.
J Phys Condens Matter ; 26(4): 045502, 2014 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-24389924

RESUMO

Films of cerium-doped LaMnO3, which has been intensively discussed as an electron-doped counterpart to hole-doped mixed-valence lanthanum manganites during the past decade, were analyzed by x-ray photoemission spectroscopy with respect to their manganese valence under photoexcitation. The comparative analysis of the Mn 3s exchange splitting of La0.7Ce0.3MnO3 (LCeMO) films in the dark and under illumination clearly shows that both oxygen reduction and illumination are able to decrease the Mn valence towards a mixed 2+/3+ state, independently of the film thickness and the degree of CeO2 segregation. Charge-injection from the photoconductive SrTiO3 substrate into the Mn eg band with carrier lifetimes in the range of tens of seconds and intrinsic generation of electron-hole pairs within the films are discussed as two possible sources of the Mn valence shift and the subsequent electron doping.

17.
J Chem Phys ; 139(21): 214702, 2013 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-24320389

RESUMO

We introduce an in situ vacuum procedure for the optimal preparation and analysis of self-assembled monolayers (SAMs) as used in organic molecular electronics on ferroelectric lead zirconate titanate (PZT) substrates. Excellent ordering of oligothiophene semiconductor layers is heavily promoted through the presence of an interfacial bi-functional SAM layer that binds to both the oxidic PZT surface and the organic semiconductor molecules. The described method can be extended to other material combinations, featuring a variety of substrate materials and molecular functionalities.

18.
Opt Express ; 21(13): 15418-29, 2013 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-23842329

RESUMO

We present the first non-resonant and non-enhanced Raman correlation spectroscopy experiments. They are conducted on a confocal microscope combined with a Raman spectrometer. The thermal fluctuations of the Raman intensities scattered by dispersions of polystyrene particles of sub-micrometric diameters are measured and analysed by deriving the autocorrelation functions (ACFs) of the intensities. We show that for particles of diameter down to 200 nm, RCS measurements are successfully obtained in spite of the absence of any source of amplification of the Raman signal. For particles of diameter ranging from 200 to 750 nm, the ACFs present a time-decay behaviour in accordance with the model of free Brownian particles. For particles of 1000 nm in diameter, the AFCs present a different behaviour with a much smaller characteristic time. This results from the dynamics of a single-Brownian particle trapped in the confocal volume by the optical forces of the focus spot.

19.
Science ; 340(6136): 1076-80, 2013 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-23723232

RESUMO

Skyrmion crystals are regular arrangements of magnetic whirls that exist in a wide range of chiral magnets. Because of their topology, they cannot be created or destroyed by smooth rearrangements of the direction of the local magnetization. Using magnetic force microscopy, we tracked the destruction of the skyrmion lattice on the surface of a bulk crystal of Fe(1-x)Co(x)Si (x = 0.5). Our study revealed that skyrmions vanish by a coalescence, forming elongated structures. Numerical simulations showed that changes of topology are controlled by singular magnetic point defects. They can be viewed as quantized magnetic monopoles and antimonopoles, which provide sources and sinks of one flux quantum of emergent magnetic flux, respectively.

20.
Eur J Clin Microbiol Infect Dis ; 31(8): 1749-52, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22143966

RESUMO

Aero-tolerant Actinomyces spp. are an under-recognised cause of cutaneous infections, in part because identification using conventional phenotypic methods is difficult and may be inaccurate. Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) is a promising new technique for bacterial identification, but with limited data on the identification of aero-tolerant Actinomyces spp. This study evaluated the accuracy of a phenotypic biochemical kit, MALDI-TOF MS and genotypic identification methods for the identification of this problematic group of organisms. Thirty aero-tolerant Actinomyces spp. were isolated from soft-tissue infections over a 2-year period. Species identification was performed by 16 s rRNA sequencing and genotypic results were compared with results obtained by API Coryne and MALDI-TOF MS. There was poor agreement between API Coryne and genotypic identification, with only 33% of isolates correctly identified to the species level. MALDI-TOF MS correctly identified 97% of isolates to the species level, with 33% of identifications achieved with high confidence scores. MALDI-TOF MS is a promising new tool for the identification of aero-tolerant Actinomyces spp., but improvement of the database is required in order to increase the confidence level of identification.


Assuntos
Actinomyces/classificação , Actinomyces/isolamento & purificação , Actinomicose/diagnóstico , Técnicas Bacteriológicas/métodos , Infecções dos Tecidos Moles/diagnóstico , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Actinomyces/química , Actinomyces/fisiologia , Actinomicose/microbiologia , Técnicas de Tipagem Bacteriana , Genes de RNAr/genética , Humanos , Tipagem Molecular , RNA Ribossômico 16S/genética , Sensibilidade e Especificidade , Infecções dos Tecidos Moles/microbiologia
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