Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 332
Filtrar
1.
BMC Oral Health ; 24(1): 195, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38321444

RESUMO

BACKGROUND: Urgent dental care may be the only place where many people, especially vulnerable groups, access care. This presents an opportunity for delivery of a behavioural intervention promoting planned dental visiting, which may help address one of the factors contributing to a socio-economic gradient in oral health. Although we know that cueing events such as having a cancer diagnosis may create a 'teachable moment' stimulating positive changes in health behaviour, we do not know whether delivering an opportunistic intervention in urgent dental care is feasible and acceptable to patients. METHODS: The feasibility study aimed to recruit 60 patients in a Dental Hospital and dental practices delivering urgent care within and outside working hours. Follow-up was by telephone, e mail and post over 4 months. RESULTS: Although the recruitment window was shortened because of COVID-19, of 47 patients assessed for eligibility, 28 were enrolled (70.1% of screened patients provided consent). A relatively high proportion were from disadvantaged backgrounds (46.4%, 13/28 receiving State benefits). Retention was 82.1% (23/28), which was also the rate of completion of the Oral Health Impact Profile co-primary outcome. The other primary outcome involved linking participant details at recruitment, with centrally-held data on services provided, with 84.6% (22/26) records partly or fully successfully matched. All intervention participants received at least some of the intervention, although we identified aspects of dental nurse training which would improve intervention fidelity. CONCLUSIONS: Despite recruitment being impacted by the pandemic, when the majority of clinical trials experienced reduced rates of recruitment, we found a high recruitment and consenting rate, even though patients were approached opportunistically to be enrolled in the trial and potentially receive an intervention. Retention rates were also high even though a relatively high proportion had a low socio-economic background. Therefore, even though patients may be in pain, and had not anticipated involvement before their urgent care visit, the study indicated that this was a feasible and acceptable setting in which to position an opportunistic intervention. This has the potential to harness the potential of the 'teachable moment' in people's lives, and provide support to help address health inequalities. TRIAL REGISTRATION: ISRCTN 10,853,330 07/10/2019.


Assuntos
COVID-19 , Humanos , Estudos de Viabilidade , Inquéritos e Questionários , Assistência Ambulatorial , Assistência Odontológica
2.
Proc Biol Sci ; 290(1997): 20222446, 2023 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-37122253

RESUMO

Killing is often an unavoidable and necessary procedure for laboratory mice involved in scientific research, and providing a humane death is vital for public acceptance. Exposure to carbon dioxide (CO2) gas is the most widely used methodology despite well proven welfare concerns. Consequently, the continued use of CO2 and its globally permitted status in legislation and guidelines presents an ethical dilemma for users. We investigated whether killing with hypobaric hypoxia via gradual decompression was associated with better welfare outcomes for killing laboratory mice. We compared the spontaneous behaviour of mice exposed to CO2, decompression or sham conditions, and used analgesic or anxiolytic interventions to determine their relative welfare impact. Gradual decompression resulted in longer times to unconsciousness and death and the pharmacological interventions support the notion of a minimally negative animal experience, while providing further evidence for pain and anxiety associated with exposure to CO2. Decompression resulted in moderate ear haemorrhage, but our welfare assessment suggests this may happen when mice are unconscious. Hence, gradual decompression could be the basis of significant refinement for killing laboratory mice. Future work should corroborate behaviour with neurobiological markers of loss of consciousness to verify the conscious phase of concern for animal welfare.


Assuntos
Dióxido de Carbono , Eutanásia Animal , Humanos , Animais , Camundongos , Eutanásia Animal/métodos , Bem-Estar do Animal , Hipóxia
3.
Trials ; 23(1): 475, 2022 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-35672830

RESUMO

BACKGROUND: People with disadvantaged backgrounds are less likely to visit the dentist for planned care, even though they have disproportionately poorer oral health. They are correspondingly more likely to experience dental problems and use urgent dental care, general practices and Accident and Emergency departments, which not only makes meeting their needs expensive, but, since these services often rely on prescriptions rather than addressing the clinical cause, can contribute to antimicrobial resistance. METHODS: The RETURN intervention has been developed with substantial community co-production, to be delivered opportunistically in urgent dental care settings. This brief intervention is delivered by dental nurses and involves material relevant to the 'in-group' targeted. The material includes booklets relating to barriers to planned dental visiting with corresponding short video clips featuring local people and including a modelling element. Dental nurses are trained to have supportive and non-judgemental conversations, assisting patients to set personal goals and action plans, which are reinforced in a follow-up text within a few weeks. A randomised controlled trial will be undertaken in 3 types of sites: dental practices delivering urgent care (a) within working hours, (b) out of hours, and (c) in a Dental Hospital. The trial will recruit 1180 adult urgent dental care users over 12 months, who have not visited a dentist for a planned care appointment for 2 years or more and do not have a dentist who they visit for routine care. It aims to investigate the effectiveness and cost-effectiveness of the intervention and to explore whether the intervention has different effects across the socio-economic gradient. Participants will be followed up at 6, 12 and 18 months after randomisation. Co-primary outcomes are attendance at a dental practice for planned care within 12 months and self-reported oral health-related quality of life at 12 months. DISCUSSION: This is a pragmatic trial, evaluating the effectiveness of the intervention under the usual condition in which it might be applied. Since dental practices work as independent contractors to the NHS, this brings implementation and fidelity challenges which will be explored and described in embedded qualitative work. TRIAL REGISTRATION: ISRCTN registry identifier ISRCTN84666712. Registered 12/04/2021.


Assuntos
Terapia Comportamental , Qualidade de Vida , Adulto , Assistência Ambulatorial , Análise Custo-Benefício , Assistência Odontológica , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
4.
J Dent Res ; 101(3): 261-269, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34636266

RESUMO

Detection and diagnosis of caries-typically undertaken through a visual-tactile examination, often with supporting radiographic investigations-is commonly regarded as being broadly effective at detecting caries that has progressed into dentine and reached a threshold where restoration is necessary. With earlier detection comes an opportunity to stabilize disease or even remineralize the tooth surface, maximizing retention of tooth tissue and preventing a lifelong cycle of restoration. We undertook a formal comparative analysis of the diagnostic accuracy of different technologies to detect and inform the diagnosis of early caries using published Cochrane systematic reviews. Forming the basis of our comparative analysis were 5 Cochrane diagnostic test accuracy systematic reviews evaluating fluorescence, visual or visual-tactile classification systems, imaging, transillumination and optical coherence tomography, and electrical conductance or impedance technologies. Acceptable reference standards included histology, operative exploration, or enhanced visual assessment (with or without tooth separation) as appropriate. We conducted 2 analyses based on study design: a fully within-study, within-person analysis and a network meta-analysis based on direct and indirect comparisons. Nineteen studies provided data for the fully within-person analysis and 64 studies for the network meta-analysis. Of the 5 technologies evaluated, the greatest pairwise differences were observed in summary sensitivity points for imaging and all other technologies, but summary specificity points were broadly similar. For both analyses, the wide 95% prediction intervals indicated the uncertainty of future diagnostic accuracy across all technologies. The certainty of evidence was low, downgraded for study limitations, inconsistency, and indirectness. Summary estimates of diagnostic accuracy for most technologies indicate that the degree of certitude with which a decision is made regarding the presence or absence of disease may be enhanced with the use of such devices. However, given the broad prediction intervals, it is challenging to predict their accuracy in any future "real world" context.


Assuntos
Suscetibilidade à Cárie Dentária , Cárie Dentária , Cárie Dentária/diagnóstico por imagem , Humanos , Sensibilidade e Especificidade , Revisões Sistemáticas como Assunto , Transiluminação
5.
Community Dent Health ; 38(4): 261-267, 2021 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-34304397

RESUMO

BACKGROUND: The COVID-19 pandemic forced a UK-wide closure of dental services. An understanding of public concerns about dental care was urgently needed to inform careful resumption of paused dental services. AIM: To describe public concerns about dental care during lockdown. BASIC RESEARCH DESIGN: Framework analysis of relevant Twitter posts identified collected using the Awario tool. RESULTS: Of 1863 tweets manually screened for eligibility, 285 were relevant, as they contained views expressed by the public. The number of tweets by country were proportionate to the population size. The key views expressed in tweets focused on: 'oral health impact' ('oral health and self-care', 'types of dental problems', 'managing symptoms at home', 'views on consequences of delaying treatment') and 'dental service or care provision' ('views on managing dental care response', 'experiences with access to dental care'). CONCLUSIONS: The impact of COVID-19 on dental services raised many physical and mental health concerns for the public, highlighting their importance. Online profiles and social media communication platforms can be used to provide convenient, and timely information on public perceptions of dental care.


Assuntos
COVID-19 , Mídias Sociais , Controle de Doenças Transmissíveis , Odontólogos , Humanos , Pandemias , SARS-CoV-2 , Reino Unido
6.
J Dent Res ; 100(7): 723-730, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33541186

RESUMO

Scale and polish (SP) and oral hygiene advice (OHA) are commonly provided in primary care dental practice to help prevent periodontal disease. These services are widely consumed by service users, incurring substantial cost, without any clear evidence of clinical benefit. This article aims to elicit general population preferences and willingness to pay (WTP) for preventative dental care services and outcomes. An online discrete-choice experiment (DCE) was completed by a nationally representative sample of the UK general population. Respondents each answered 10 choice tasks that varied in terms of service attributes (SP, OHA, and provider of care), outcomes (bleeding gums and aesthetics), and cost. Choice tasks were selected using a pivoted segmented experimental design to improve task realism. An error components panel logit model was used to analyze the data. Marginal WTP (mWTP) for each attribute and level was calculated. In total, 667 respondents completed the DCE. Respondents valued more frequent SP, care provided by a dentist, and personalized OHA. Respondents were willing to pay for dental packages that generated less frequent ("never" or "hardly ever") bleeding on brushing and teeth that look and feel at least "moderately clean." Respondents were willing to pay more (+£145/y) for improvements in an aesthetic outcome from "very unclean" (-£85/y) to "very clean" (+£60/y) than they were for reduced bleeding frequency (+£100/y) from "very often" (-£54/y) to "never" (+£36/y). The general population value routinely provided SP, even in the absence of reductions in bleeding on brushing. Dental care service providers must consider service user preferences, including preferences for both health and nonhealth outcomes, as a key factor in any service redesign. Furthermore, the results provide mWTP estimates that can be used in cost-benefit analysis of these dental care services.


Assuntos
Assistência Odontológica , Estética Dentária , Atenção à Saúde , Humanos , Higiene Bucal , Preferência do Paciente , Inquéritos e Questionários
7.
J Dent Res ; 99(1): 36-43, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31771385

RESUMO

This multicenter 3-arm, parallel-group, patient-randomized controlled trial compared clinical effectiveness of 3 treatment strategies over 3 y for managing dental caries in primary teeth in UK primary dental care. Participants aged 3 to 7 y with at least 1 primary molar with dentinal carious lesion were randomized across 3 arms (1:1:1 via centrally administered system with variable-length random permuted blocks): C+P, conventional carious lesion management (complete carious tooth tissue removal and restoration placement) with prevention; B+P, biological management (sealing in carious tooth tissue restoratively) with prevention; and PA, prevention alone (diet, plaque removal, fluorides, and fissure sealants). Parents, children, and dentists were not blind to allocated arm. Co-primary outcomes were 1) the proportion of participants with at least 1 episode of dental pain and/or infection and 2) the number of episodes of dental pain and/or infection during follow-up (minimum, 23 mo). In sum, 1,144 participants were randomized (C+P, n = 386; B+P, n = 381; PA, n = 377) by 72 general dental practitioners, of whom 1,058 (C+P, n = 352; B+P, n = 352; PA, n = 354) attended at least 1 study visit and were included in the primary analysis. The median follow-up was 33.8 mo (interquartile range, 23.8 to 36.7). Proportions of participants with at least 1 episode of dental pain and/or infection were as follows: C+P, 42%; B+P, 40%; PA, 45%. There was no evidence of a difference in incidence of dental pain and/or infection when B+P (adjusted risk difference [97.5% CI]: -2% [-10% to 6%]) or PA (4% [-4% to 12%]) was compared with C+P. The mean (SD) number of episodes of dental pain and/or infection were as follows: C+P, 0.62 (0.95); B+P, 0.58 (0.87); and PA, 0.72 (0.98). Superiority could not be concluded for number of episodes between B+P (adjusted incident rate ratio (97.5% CI): 0.95 [0.75 to 1.21]) or PA (1.18 [0.94 to 1.48]) and C+P. In conclusion, there was no evidence of a difference among the 3 treatment approaches for incidence or number of episodes of dental pain and/or infection experienced by these participants with high caries risk and established disease (trial registration: ISRCTN77044005).


Assuntos
Cárie Dentária , Criança , Pré-Escolar , Cárie Dentária/prevenção & controle , Cárie Dentária/terapia , Odontólogos , Humanos , Selantes de Fossas e Fissuras , Papel Profissional , Dente Decíduo
8.
BMC Oral Health ; 19(1): 88, 2019 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-31126270

RESUMO

BACKGROUND: Dental caries in the expanding elderly, predominantly-dentate population is an emerging public health concern. Elderly individuals with heavily restored dentitions represent a clinical challenge and significant financial burden for healthcare systems, especially when their physical and cognitive abilities are in decline. Prescription of higher concentration fluoride toothpaste to prevent caries in older populations is expanding in the UK, significantly increasing costs for the National Health Services (NHS) but the effectiveness and cost benefit of this intervention are uncertain. The Reflect trial will evaluate the effectiveness and cost benefit of General Dental Practitioner (GDP) prescribing of 5000 ppm fluoride toothpaste and usual care compared to usual care alone in individuals 50 years and over with high-risk of caries. METHODS/DESIGN: A pragmatic, open-label, randomised controlled trial involving adults aged 50 years and above attending NHS dental practices identified by their dentist as having high risk of dental caries. Participants will be randomised to prescription of 5000 ppm fluoride toothpaste (frequency, amount and duration decided by GDP) and usual care only. 1200 participants will be recruited from approximately 60 dental practices in England, Scotland and Northern Ireland and followed up for 3 years. The primary outcome will be the proportion of participants receiving any dental treatment due to caries. Secondary outcomes will include coronal and root caries increments measured by independent, blinded examiners, patient reported quality of life measures, and economic outcomes; NHS and patient perspective costs, willingness to pay, net benefit (analysed over the trial follow-up period and modelled lifetime horizon). A parallel qualitative study will investigate GDPs' practises of and beliefs about prescribing the toothpaste and patients' beliefs and experiences of the toothpaste and perceived impacts on their oral health-related behaviours. DISCUSSION: The Reflect trial will provide valuable information to patients, policy makers and clinicians on the costs and benefits of an expensive, but evidence-deficient caries prevention intervention delivered to older adults in general dental practice. TRIAL REGISTRATION: ISRCTN: 2017-002402-13 registered 02/06/2017, first participant recruited 03/05/2018. Ethics Reference No: 17/NE/0329/233335. Funding Body: Health Technology Assessment funding stream of National Institute for Health Research. Funder number: HTA project 16/23/01. Trial Sponsor: Manchester University NHS Foundation Trust, Oxford Road, Manchester, M13 9WL. The Trial was prospectively registered.


Assuntos
Cárie Dentária , Fluoretos , Cremes Dentais , Idoso , Análise Custo-Benefício , Inglaterra , Humanos , Pessoa de Meia-Idade , Qualidade de Vida , Escócia
9.
Clin Microbiol Infect ; 25(2): 163-168, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30195471

RESUMO

SCOPE: Antibiotic stewardship programmes (ASPs) are necessary in hospitals to improve the judicious use of antibiotics. While ASPs require complex change of key behaviours on individual, team organization and policy levels, evidence from the behavioural sciences is underutilized in antibiotic stewardship studies across the world, including high-income countries (HICs). A consensus procedure was performed to propose research priority areas for optimizing effective implementation of ASPs in hospital settings using a behavioural perspective. METHODS: A workgroup for behavioural approaches to ASPs was convened in response to the fourth call for leading expert network proposals by the Joint Programming Initiative on Antimicrobial Resistance (JPIAMR). Eighteen clinical and academic specialists in antibiotic stewardship, implementation science and behaviour change from four HICs with publicly funded healthcare systems (e.g. Canada, Germany, Norway and the UK) met face-to-face to agree on broad research priority areas using a structured consensus method. Question addressed and recommendations: The consensus process assessing the ten identified research priority areas resulted in recommendations that need urgent scientific interest and funding to optimize effective implementation of ASPs for hospital inpatients in HICs with publicly funded healthcare systems. We suggest and detail behavioural science evidence-guided research efforts in the following areas: (a) comprehensively identifying barriers and facilitators to implementing ASPs and clinical recommendations intended to optimize antibiotic prescribing; (b) identifying actors ('who') and actions ('what needs to be done') of ASPs and clinical teams; (c) synthesizing available evidence to support future research and planning for ASPs; (d) specifying the activities in current ASPs with the purpose of defining a control group for comparison with new initiatives; (e) defining a balanced set of outcomes and measures to evaluate the effects of interventions focused on reducing unnecessary exposure to antibiotics; (f) conducting robust evaluations of ASPs with built-in process evaluations and fidelity assessments; (g) defining and designing ASPs; (h) establishing the evidence base for impact of ASPs on resistance; (i) investigating the role and impact of government and policy contexts on ASPs; and (j) understanding what matters to patients in ASPs in hospitals. CONCLUSIONS: Assessment, revisions and updates of our priority-setting exercise should be considered at intervals of 2 years. To propose research priority areas in low- and middle-income countries, the methodology reported here could be applied.


Assuntos
Antibacterianos/administração & dosagem , Antibacterianos/uso terapêutico , Gestão de Antimicrobianos , Consenso , Hospitais , Projetos de Pesquisa , Humanos , Controle de Infecções , Padrões de Prática Médica
10.
Br Dent J ; 225(7): 645-656, 2018 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-30310225

RESUMO

Introduction Despite UK dental guidance recommending opportunistic health promotion, it's rare for GDPs to discuss more than oral hygiene with their patients. The ENGAGE intervention incorporates UK guidance and evidence-based behaviour change techniques to motivate patients to make lifestyle changes (reduce smoking, alcohol consumption and/or improve diet). It was designed to take less than five minutes and be delivered during a routine dental check-up, and includes a take-home patient handout signposting to free NHS lifestyle counselling helpline services.Aims To determine the feasibility (patient and GDP acceptance) of implementing ENGAGE in Scottish dental primary care. The overall aim is to examine feasibility UK-wide before testing its effectiveness for influencing patient outcomes in a multi-centre UK trial.Methods Study 1: patient survey: N = 1000 adults from all health boards in Scotland were randomly selected from an NHS data base of medical patients and emailed the study invitation and link to an online questionnaire. Study 2: GDP workshop, audit, survey: N = 50 GDPs across Scotland were invited to participate in the training workshop (limited to the first 20 applicants), implement the intervention with their next 20 adult patients in for a check-up, audit their experience, then complete an online questionnaire.Results Study 1: 200 people completed the survey (52% male; 37% were 55 years or younger; 90% had visited their dentist in the previous 12 months). Less than (<) 15% were asked about their smoking, alcohol intake and/or diet when they last visited their dentist for a check-up; <10% would be embarrassed/offended if their dentist or dental hygienist asked them lifestyle questions during a dental check-up; more than (>) 70% would be reassured by the professionalism of their dentist or dental hygienist if they were asked; <4% would be embarrassed/offended if given a leaflet with NHS helpline information by their dentist. Study 2: N = 18 GDPs from nine out of 14 NHS regional health boards in Scotland delivered the ENGAGE intervention to 335 patients (averaging 18 patients each). N = 17/18 participants agreed that this intervention could be delivered during a check-up, was an improvement on what they currently did and thought that it may make a difference to what their patients thought, felt, and/or did about reducing health risk.Conclusion The ENGAGE intervention is feasible to implement in Scottish dental primary care. Comments from patient and GDP participants will inform its development and further feasibility studies set in other UK regions.


Assuntos
Assistência Odontológica/organização & administração , Promoção da Saúde/métodos , Entrevista Motivacional , Atenção Primária à Saúde/organização & administração , Idoso , Atitude do Pessoal de Saúde , Inquéritos de Saúde Bucal , Estudos de Viabilidade , Feminino , Estilo de Vida Saudável , Humanos , Masculino , Pessoa de Meia-Idade , Educação de Pacientes como Assunto , Avaliação de Programas e Projetos de Saúde , Medição de Risco , Escócia
11.
EBioMedicine ; 28: 120-127, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29396306

RESUMO

BACKGROUND: Rapid Point-Of-Care Tests for Chlamydia trachomatis (CT) may reduce onward transmission and reproductive sexual health (RSH) sequelae by reducing turnaround times between diagnosis and treatment. The io® single module system (Atlas Genetics Ltd.) runs clinical samples through a nucleic acid amplification test (NAAT)-based CT cartridge, delivering results in 30min. METHODS: Prospective diagnostic accuracy study of the io® CT-assay in four UK Genito-Urinary Medicine (GUM)/RSH clinics on additional-to-routine self-collected vulvovaginal swabs. Samples were tested "fresh" within 10days of collection, or "frozen" at -80°C for later testing. Participant characteristics were collected to assess risk factors associated with CT infection. RESULTS: CT prevalence was 7.2% (51/709) overall. Sensitivity, specificity, positive and negative predictive values of the io® CT assay were, respectively, 96.1% (95% Confidence Interval (CI): 86.5-99.5), 97.7% (95%CI: 96.3-98.7), 76.6% (95%CI: 64.3-86.2) and 99.7% (95%CI: 98.9-100). The only risk factor associated with CT infection was being a sexual contact of an individual with CT. CONCLUSIONS: The io® CT-assay is a 30-min, fully automated, high-performing NAAT currently CE-marked for CT diagnosis in women, making it a highly promising diagnostic to enable specific treatment, initiation of partner notification and appropriately intensive health promotion at the point of care.


Assuntos
Infecções por Chlamydia/diagnóstico , Infecções por Chlamydia/microbiologia , Chlamydia trachomatis/fisiologia , Genitália/microbiologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Sistemas Automatizados de Assistência Junto ao Leito , Feminino , Humanos , Estudos Prospectivos , Padrões de Referência , Fatores de Risco
12.
Sci Rep ; 7(1): 15460, 2017 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-29133957

RESUMO

The ability to control a magnetic phase with an electric field is of great current interest for a variety of low power electronics in which the magnetic state is used either for information storage or logic operations. Over the past several years, there has been a considerable amount of research on pathways to control the direction of magnetization with an electric field. More recently, an alternative pathway involving the change of the magnetic state (ferromagnet to antiferromagnet) has been proposed. In this paper, we demonstrate electric field control of the Anomalous Hall Transport in a metamagnetic FeRh thin film, accompanying an antiferromagnet (AFM) to ferromagnet (FM) phase transition. This approach provides us with a pathway to "hide" or "reveal" a given ferromagnetic region at zero magnetic field. By converting the AFM phase into the FM phase, the stray field, and hence sensitivity to external fields, is decreased or eliminated. Using detailed structural analyses of FeRh films of varying crystalline quality and chemical order, we relate the direct nanoscale origins of this memory effect to site disorder as well as variations of the net magnetic anisotropy of FM nuclei. Our work opens pathways toward a new generation of antiferromagnetic - ferromagnetic interactions for spintronics.

13.
Nat Mater ; 16(10): 1003-1009, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28783161

RESUMO

Systems that exhibit phase competition, order parameter coexistence, and emergent order parameter topologies constitute a major part of modern condensed-matter physics. Here, by applying a range of characterization techniques, and simulations, we observe that in PbTiO3/SrTiO3 superlattices all of these effects can be found. By exploring superlattice period-, temperature- and field-dependent evolution of these structures, we observe several new features. First, it is possible to engineer phase coexistence mediated by a first-order phase transition between an emergent, low-temperature vortex phase with electric toroidal order and a high-temperature ferroelectric a1/a2 phase. At room temperature, the coexisting vortex and ferroelectric phases form a mesoscale, fibre-textured hierarchical superstructure. The vortex phase possesses an axial polarization, set by the net polarization of the surrounding ferroelectric domains, such that it possesses a multi-order-parameter state and belongs to a class of gyrotropic electrotoroidal compounds. Finally, application of electric fields to this mixed-phase system permits interconversion between the vortex and the ferroelectric phases concomitant with order-of-magnitude changes in piezoelectric and nonlinear optical responses. Our findings suggest new cross-coupled functionalities.

14.
Phys Rev Lett ; 116(9): 097203, 2016 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-26991197

RESUMO

We report a giant, ∼22%, electroresistance modulation for a metallic alloy above room temperature. It is achieved by a small electric field of 2 kV/cm via piezoelectric strain-mediated magnetoelectric coupling and the resulting magnetic phase transition in epitaxial FeRh/BaTiO_{3} heterostructures. This work presents detailed experimental evidence for an isothermal magnetic phase transition driven by tetragonality modulation in FeRh thin films, which is in contrast to the large volume expansion in the conventional temperature-driven magnetic phase transition in FeRh. Moreover, all the experimental results in this work illustrate FeRh as a mixed-phase model system well similar to phase-separated colossal magnetoresistance systems with phase instability therein.

17.
Nature ; 530(7589): 198-201, 2016 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-26814971

RESUMO

The complex interplay of spin, charge, orbital and lattice degrees of freedom provides a plethora of exotic phases and physical phenomena. In recent years, complex spin topologies have emerged as a consequence of the electronic band structure and the interplay between spin and spin-orbit coupling in materials. Here we produce complex topologies of electrical polarization--namely, nanometre-scale vortex-antivortex (that is, clockwise-anticlockwise) arrays that are reminiscent of rotational spin topologies--by making use of the competition between charge, orbital and lattice degrees of freedom in superlattices of alternating lead titanate and strontium titanate layers. Atomic-scale mapping of the polar atomic displacements by scanning transmission electron microscopy reveals the presence of long-range ordered vortex-antivortex arrays that exhibit nearly continuous polarization rotation. Phase-field modelling confirms that the vortex array is the low-energy state for a range of superlattice periods. Within this range, the large gradient energy from the vortex structure is counterbalanced by the corresponding large reduction in overall electrostatic energy (which would otherwise arise from polar discontinuities at the lead titanate/strontium titanate interfaces) and the elastic energy associated with epitaxial constraints and domain formation. These observations have implications for the creation of new states of matter (such as dipolar skyrmions, hedgehog states) and associated phenomena in ferroic materials, such as electrically controllable chirality.

18.
Br Dent J ; 218(7): 387-91; discussion 391, 2015 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-25858735

RESUMO

AIMS: To understand current practice and the beliefs of dentists and hygienists towards factors which may influence the management of patients with periodontal diseases in primary dental care in Scotland. To inform the scope of a guidance publication and the future development of diagnostic analyses tools. METHODS: A qualitative approach of semi-structured telephone interviews with a randomly selected sample of dentists and hygienists was used. Interviews continued until saturation was reached and were audio-recorded and transcribed verbatim. The data were analysed using the method of framework analysis. To increase the participation of hygienists the topic guide was adapted into a self-reporting questionnaire and posted to all hygienists in Scotland. RESULTS: Eighteen dentists and three hygienists were interviewed. Key themes identified were extent of control over working environment, capabilities to treat appropriately and changing patients' oral hygiene behaviour. Factors which facilitated the management of patients with periodontal diseases were 'access to a hygienist' and 'beliefs about capabilities', while 'routine and habit', 'motivation of patients' and 'time and money' were perceived as barriers. Some evidence of variation in treatment provision and of varying levels of confidence among practitioners about treating more advanced periodontal conditions was identified. Two hundred and thirty-seven hygienists returned the postal questionnaire. Agreement was found with the views of the interviewed hygienists on beliefs about capabilities and routine record-keeping. CONCLUSION: To improve the periodontal health of patients requires consideration of both extrinsic and intrinsic factors present in primary dental care. Practitioners would find having guidance on managing patients with basic periodontal examinations of three and four, referral criteria to secondary care, record-keeping and techniques to change patients' oral hygiene behaviour particularly useful. Applying the evaluative framework pre-publication indicated where knowledge translation interventions may be required in the future.


Assuntos
Assistência Odontológica , Periodontia/métodos , Assistência Odontológica/métodos , Feminino , Humanos , Entrevistas como Assunto , Masculino , Higiene Bucal/métodos , Doenças Periodontais/diagnóstico , Doenças Periodontais/terapia , Pesquisa Qualitativa , Escócia , Inquéritos e Questionários
19.
Transfus Med ; 25(4): 239-42, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25800958

RESUMO

BACKGROUND/OBJECTIVE: The standard medical therapy for haemochromatosis is iron removal by regular phlebotomy. Current guidelines suggest that this blood should be made available through national blood services. Here, we describe a pilot facilitating the process of blood donation amongst uncomplicated haemochromatosis patients. METHODS/MATERIALS: At a dedicated clinic, patients with uncomplicated haemochromatosis interested in becoming blood donors were offered an information leaflet and self-referral application. Upon receipt, members of the local Blood Service contacted them to confirm eligibility to donate. Data on demographics and clinical characteristics, including HFE (high Fe) genotype, co-morbidities, alcohol consumption and body mass index, were collected. RESULTS: Since establishing the clinic, 140 patients have attended (93 male) with median age 57. Most (n = 125; 89%) had uncomplicated haemochromatosis. Of these, 55 were potentially eligible blood donors. Amongst those eligible, there are now 29 regular blood donors, including 23 new. CONCLUSION: There is an interest and willingness to donate blood through the Blood Service amongst uncomplicated haemochromatosis patients undergoing therapeutic phlebotomy. Since the introduction of this facilitation process, we have significantly increased the number of regular donors amongst this cohort. If this process was to be replicated more widely across the UK, this could have a significant impact on the blood donor pool.


Assuntos
Doadores de Sangue , Hemocromatose , Obtenção de Tecidos e Órgãos/métodos , Adulto , Idoso de 80 Anos ou mais , Doadores de Sangue/psicologia , Doadores de Sangue/provisão & distribuição , Patógenos Transmitidos pelo Sangue , Seleção do Doador/normas , Feminino , Hemocromatose/sangue , Hemocromatose/complicações , Hemocromatose/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Motivação , Comunicação Persuasiva , Flebotomia , Projetos Piloto , Reino Unido , Adulto Jovem
20.
Nat Commun ; 6: 5959, 2015 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-25564764

RESUMO

In numerous systems, giant physical responses have been discovered when two phases coexist; for example, near a phase transition. An intermetallic FeRh system undergoes a first-order antiferromagnetic to ferromagnetic transition above room temperature and shows two-phase coexistence near the transition. Here we have investigated the effect of an electric field to FeRh/PMN-PT heterostructures and report 8% change in the electrical resistivity of FeRh films. Such a 'giant' electroresistance (GER) response is striking in metallic systems, in which external electric fields are screened, and thus only weakly influence the carrier concentrations and mobilities. We show that our FeRh films comprise coexisting ferromagnetic and antiferromagnetic phases with different resistivities and the origin of the GER effect is the strain-mediated change in their relative proportions. The observed behaviour is reminiscent of colossal magnetoresistance in perovskite manganites and illustrates the role of mixed-phase coexistence in achieving large changes in physical properties with low-energy external perturbation.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...