RESUMO
Peripheral neural stimulation is a major problem in current gradient coil designs. Induced current problems in patients relate directly to gradient strength and modulation frequency. Present designs of gradient coil tend to limit ultra-high-speed imaging methods such as echo-planar imaging (EPI) and echo-volumar imaging (EVI) because of the effect of induced currents in the patient which produce neural stimulation resulting in tingling sensations and involuntary muscle twitch. Neural stimulation could also trigger epileptic fits and/or cardiac fibrillation. For reduction of induced currents, an important aspect is the coil geometry. It is desirable to design the gradient coil in such a way as to prevent closed loop circulating currents within the body. Preliminary results using a four-sector gradient coil with a rectangular geometry, operating in a low mutual coupling mode and using passive E-field control, indicate significant reduction of the E-field within the subject volume of the coil, leading to a reduction of induced currents in a patient. Such a reduction allows safer operation using higher magnetic gradient strengths together with faster scans. Currently very fast scans are prohibited by virtue of the neural stimulation effects produced in present standard coil geometries.
Assuntos
Imagem Ecoplanar/métodos , Imageamento por Ressonância Magnética/instrumentação , Imageamento por Ressonância Magnética/métodos , Neurônios/patologia , Algoritmos , Animais , Simulação por Computador , Campos Eletromagnéticos , Eletrônica Médica/instrumentação , Desenho de Equipamento , Humanos , Magnetismo , Modelos Estatísticos , Oscilometria/instrumentação , SoftwareRESUMO
Genotype 3 hepatitis E virus (HEV) can lead to persistent infections in immunocompromised hosts. A recently available commercial assay for the detection of HEV antigen (HEV-Ag ELISA, Wantai diagnostics) may enable the study of HEV-Ag dynamics in such persistent infections, however currently there is no confirmatory test available. We generated a putative neutralising reagent from a pool of four convalescent blood donor samples and explored neutralising activity against HEV antigens from clinical samples, HEV tissue-culture and virus-like particles. Using this neutralisation method we were able to differentiate true reactivity from non-specific reactivity in plasma, stool and urine samples. This could also facilitate the introduction of HEV-Ag detection as a screening assay or the study of HEV-Ag in different body fluids.
Assuntos
Ensaio de Imunoadsorção Enzimática , Antígenos E da Hepatite B/isolamento & purificação , Hepatite E/diagnóstico , Fezes/virologia , Anticorpos Anti-Hepatite/sangue , Hepatite E/imunologia , Vírus da Hepatite E , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Testes de Neutralização , RNA Viral/genética , Kit de Reagentes para Diagnóstico , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: To evaluate the effect of an Inpatient Geriatric Consultation Team on patient outcome. DESIGN: Randomized controlled clinical trial. SETTING: A non-academic-affiliated 503-bed community hospital. PATIENTS: All inpatients over the age of 70 years. Sixty-two patients received multidimensional geriatric assessment, and 58 patients received no intervention. INTERVENTION: Team assessment, leading to formal recommendations to the attending physician. MEASUREMENTS: Data were collected on hospital length of stay, referrals to community service, discharge destination, hospital readmissions in 6 months, number of post-discharge physician visits, and change in functional status. Mortality at 6 months and at 1 year was determined for each patient. MAIN RESULTS: At 6 months, 12/58 patients (21%) had died in the control group versus 3/62 (6%) patients in the experimental group (P = 0.01). During hospitalization, the length-of-stay was 10.1 days for the control group versus 9.0 days for the experimental group (P = 0.20). The control group had significantly more readmissions (0.6 per patient vs 0.3 per patient, P = 0.02). A higher number of experimental patients, 22% (13/59), showed improvement in ADL scores compared with 7% (4/46) of control patients, P = 0.07. At one year for all randomized patients, 7/68 (10%) of experimental patients and 13/64 (20%) of control patients had died. CONCLUSIONS: Short-term mortality can be reduced in community inpatient acute hospital settings by comprehensive geriatric consultation teams. Important differences in mortality remain at 1 year of followup. Trends towards improved functional status and fewer hospital readmissions favor the intervention group.
Assuntos
Avaliação Geriátrica , Hospitalização , Hospitais Comunitários , Atividades Cotidianas , Idoso , Feminino , Hospitais com mais de 500 Leitos , Humanos , Tempo de Internação , Masculino , Mortalidade , Readmissão do PacienteRESUMO
BACKGROUND: Autochthonous (locally acquired) hepatitis E is increasingly recognised in developed countries, and is thought to be a porcine zoonosis. A range of extra-hepatic manifestations of hepatitis E infection have been described, but have never been systematically studied. AIM: To report the extra-hepatic manifestations of hepatitis E virus. METHODS: Retrospective review of data of 106 cases of autochthonous hepatitis E (acute n = 105, chronic n = 1). RESULTS: Eight (7.5%) cases presented with neurological syndromes, which included brachial neuritis, Guillain-Barré syndrome, peripheral neuropathy, neuromyopathy and vestibular neuritis. Patients with neurological syndromes were younger (median age 40 years, range 34-92 years, P = 0.048) and had a more modest transaminitis (median ALT 471 IU/L, P = 0.015) compared to cases without neurological symptoms [median age 64 years (range 18-88 years), median ALT 1135 IU/L]. One patient presented with a cardiac arrhythmia,twelve patients (11.3%) presented with thrombocytopenia, fourteen (13.2%) with lymphocytosis and eight (7.5%) with a lymphopenia, none of which had any clinical consequence. Serum electrophoresis was performed in 65 patients at presentation, of whom 17 (26%) had a monoclonal gammopathy of uncertain significance. Two cases developed haematological malignancies, acute myeloid leukaemia and duodenal plasmacytoma, 18 and 36 months after presenting with acute hepatitis E infection. CONCLUSIONS: A range of extra-hepatic manifestations can occur with hepatitis E. Neurological and haematological features of hepatitis E infection are relatively frequent in this UK cohort, and result in significant morbidity which warrants further study.
Assuntos
Doenças Hematológicas/epidemiologia , Hepatite E/epidemiologia , Hepatite E/patologia , Doenças do Sistema Nervoso/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Inglaterra/epidemiologia , Feminino , Genótipo , Hepatite E/fisiopatologia , Hepatite E/psicologia , Vírus da Hepatite E/genética , Vírus da Hepatite E/patogenicidade , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Estudos Retrospectivos , Avaliação de Sintomas/estatística & dados numéricos , Adulto JovemAssuntos
Selênio/metabolismo , Cloreto de Tolônio/síntese química , Animais , Cães , Rim/metabolismo , Fígado/metabolismo , Pulmão/metabolismo , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Miocárdio/metabolismo , Pâncreas/metabolismo , Glândulas Paratireoides/metabolismo , Radioisótopos , Selênio/sangue , Espectrofotometria Ultravioleta , Baço/metabolismo , Relação Estrutura-Atividade , Glândula Tireoide/metabolismo , Cloreto de Tolônio/sangue , Cloreto de Tolônio/metabolismoRESUMO
Results are presented for a model three-axis gradient coil incorporating active acoustic control which is applied to the switched read gradient during a single-shot rapid echo-planar imaging (EPI) sequence at a field strength of 3.0 T. The total imaging acquisition time was 10.6 ms. Substantial noise reduction is achieved both within the magnet bore and outside the magnet. Typical internal noise reduction over the specimen area is 40 dB(A) whereas outside the acoustic chamber the noise level is reduced by 60-67 dB(A). However these results are relative to a control winding which is switched in phase, adding 6 dB(A) in its non-optimized mode, which is included in the quoted figures.
Assuntos
Imageamento por Ressonância Magnética/instrumentação , Acústica , Engenharia Biomédica , Imagem Ecoplanar/instrumentação , Desenho de Equipamento , Humanos , Modelos Teóricos , Ruído/prevenção & controle , Imagens de Fantasmas , Vibração/efeitos adversosRESUMO
The author describes institutional staff restructuring, considering traditional downsizing and a more strategically planned restructuring, "rightsizing", which seeks to achieve operational and financial objectives with considerably less trauma.
Assuntos
Emprego , Administração de Recursos Humanos em Hospitais/métodos , Gestão de Recursos Humanos , Admissão e Escalonamento de Pessoal , Comunicação , Empatia , Humanos , Liderança , Salários e Benefícios , Estados Unidos , Orientação VocacionalRESUMO
The career planning process is often illustrated as the last step in an ever-changing work environment. The technical, professional, managerial, and interpersonal skills to successfully perform and succeed in this rapidly changing work environment are essential. There is a very real and immediate threat that many of the professional skills that we have learned yesterday and today will be obsolete and insufficient to cope with the inevitable changes in the future. While most professionals are aware of the very real threat of skill obsolescence, few take the opportunity to do definitive career planning regarding their future. The career planning process is designed to help individuals examine their careers; evaluate their training and educational needs; and develop some specific action plans to maintain, enhance, and reevaluate the relevance of their professional and managerial skills in a work environment that values rapid change and adaptation.
Assuntos
Mobilidade Ocupacional , Técnicas de Planejamento , Tomada de Decisões , Guias como Assunto , Humanos , Competência Profissional , Desenvolvimento de Pessoal , Orientação VocacionalRESUMO
The entire job or career search can best be illustrated as a ladder. With the bottom rung as the beginning of the job or career search process, the next rung in the self-assessment process is the preparation of an effective resume, and ultimately the top rung of the ladder, or the final objective, is securing the appropriate position. The goal in each step of the process is to understand yourself and to present yourself as positively as possible, to overcome any negative aspects that would inhibit a competitive job offer, and to be ultimately successful in the interview process. All of this must be achieved using the most effective, efficient method in the shortest possible time while still facing serious and aggressive competition. The long road ahead can be made easier and can make you stand out from the crowd if the sometimes difficult and time-consuming groundwork provides your ladder with the foundation necessary to reach that top rung as a winner.
Assuntos
Mobilidade Ocupacional , Autoavaliação (Psicologia) , Objetivos , Humanos , Técnicas de Planejamento , Competência ProfissionalRESUMO
The new principles of active acoustic control in gradient coil design are introduced and theoretical expressions are developed for the far field acoustic output for a coil system comprising four or more flat rectangular coil sectors. Each sector consists of a split plate arrangement in which are embedded two windings, an outer primary winding and a narrow inner re-entrant loop control winding immediately adjacent to and surrounding the split or air gap. The wire spacing of the control winding is made small so as not to affect substantially the magnetic field created by the primary winding. Experimental results are produced for one sector which show an average difference in acoustic output of 34.9 dB when the control winding is appropriately driven. The theoretical expressions developed are used to fit the experimental data and indicate good agreement with regard to the form of the output response.
Assuntos
Acústica , Imageamento por Ressonância Magnética/instrumentação , Fenômenos Biofísicos , Biofísica , Desenho de Equipamento , Humanos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Modelos TeóricosRESUMO
The new principles of active acoustic control in gradient coil design recently introduced by Mansfield and Haywood (MAGMA 1999;8(Suppl 1):55) are further developed theoretically for the far-field acoustic output for a single sector of a coil system comprising four or more flat rectangular coil sectors. Each sector consists of a split plate arrangement in which are embedded two windings, an outer primary winding and a narrow inner re-entrant loop control winding immediately adjacent to and surrounding the split or air gap. The wire spacing of the control winding is made small so as not to affect substantially the magnetic field created by the primary winding. Experimental results are presented for two sectors each made of a different readily available plastic material and tested over a range of frequencies. They both show substantial average reductions in acoustic output over the full output when the control winding is appropriately driven. New theoretical expressions are derived for particular frequencies based on normal mode expansions for the plate. This new approach is better able to explain the acoustic output difference between the full and reduced output modes. Empirical expressions are also developed which include longitudinal as well as transverse plate characteristics and used to fit the experimental acoustic output data as a function of frequency and indicate good agreement with regard to both the form and amplitude of the acoustic output response.
Assuntos
Imageamento por Ressonância Magnética/instrumentação , Acústica , MatemáticaRESUMO
The concept of active acoustic control was recently introduced by Mansfield and Haywood (MAGMA 2000:10:147-151) to ameliorate the problem of acoustic noise from MRI, particularly that from high-speed EPI. A 30 dB reduction in noise was previously achieved with the use of acoustic control operating at spot frequencies within a narrow band. In this work, a new acoustic gradient pulse is introduced that comprises an oscillating gradient of finite duration, incorporating a combination of frequencies within this band designed for use as the switched read gradient in echo-planar imaging (EPI). Employing this pulse with active acoustic control results in a reduction of acoustic noise by 50 dB.
Assuntos
Acústica , Imagem Ecoplanar/métodos , Eletricidade , HumanosRESUMO
Peripheral neural stimulation is a major problem in current gradient coil designs. Induced current problems in patients relate directly to gradient strength and modulation frequency. Current designs of gradient coil tend to limit ultra-high-speed imaging methods such as echo-planar imaging through the effect of induced currents which produce tingling sensations and involuntary muscle twitch. Neural stimulation could also trigger epileptic fits and/or cardiac fibrillation. For reduction of induced currents, an important aspect is the coil geometry. It is desirable to design the gradient coil in such a way as to prevent closed loop circulating currents within the body. Preliminary results using a four-sector gradient coil with rectangular geometry, operating in a low mutual coupling mode, indicate significant reduction in the E-field within the subject volume of the coil. Reduction in induced currents in the patient allows safer operation at higher magnetic field strengths together with faster scans currently prohibited through neural stimulation effects in standard coil geometries.
Assuntos
Segurança de Equipamentos/instrumentação , Potenciais Evocados/efeitos da radiação , Imageamento por Ressonância Magnética/efeitos adversos , Imageamento por Ressonância Magnética/instrumentação , Magnetismo/efeitos adversos , Magnetismo/instrumentação , Modelos Biológicos , Neurônios/efeitos da radiação , Simulação por Computador , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Segurança de Equipamentos/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Doses de Radiação , Radiometria/métodosRESUMO
PURPOSE: The purpose of this longitudinal whitening study was to determine the stability, post-treatment side effects, and patient satisfaction at 90 months post treatment after 6 months of active treatment of tetracycline-stained teeth with 10% carbamide peroxide. MATERIALS AND METHODS: Fifteen of 21 participants enrolled in the study (71%) were contacted and asked to participate in a survey concerning their whitening experience. Participants were asked whether there had been any change in the shade of their teeth after treatment and if they had experienced any side effects that they believed were treatment related. Eight of the 15 participated in a clinical examination. RESULTS: Nine participants (60%) reported no obvious shade change or only a slight darkening not noticed by others. None reported darkening back to the original shade; however, four had re-treated their teeth. Examiners were in agreement with the participants' perception of shade change upon comparing pretreatment and post-treatment photographs and Vita shade (Vita Zahnfabrik D-79713, Bad Sackingen, Germany) values. The degree of improvement over the pretreatment shade was significant for the 90-month post-treatment shade (p < .01). All respondents (n = 15) denied having to have a crown or root canal or tooth sensitivity that they believed was treatment related. CLINICAL SIGNIFICANCE: The results of this study of nightguard vital bleaching indicate that tetracycline-stained teeth can be whitened successfully using extended treatment time and that shade stability may last at least 90 months post treatment (range 84-100 mo). Patients participating in this study were over-whelmingly positive about the procedure in terms of shade retention and lack of post-treatment side effects.
Assuntos
Antibacterianos/efeitos adversos , Oxidantes/uso terapêutico , Peróxidos/uso terapêutico , Tetraciclina/efeitos adversos , Clareamento Dental/métodos , Descoloração de Dente/tratamento farmacológico , Ureia/uso terapêutico , Adulto , Peróxido de Carbamida , Dispositivos para o Cuidado Bucal Domiciliar , Combinação de Medicamentos , Feminino , Humanos , Estudos Longitudinais , Masculino , Satisfação do Paciente , Descoloração de Dente/induzido quimicamente , Ureia/análogos & derivadosRESUMO
The case of a 19-year-old severly mentally retarded Black female with a 48,XXXX chromosome constitution is reported. She had low-set ears, minimum webbing of the neck, small inverted nipples, and tapering of the extremities. All ten digital patterns of the fingers were ulnar loops, resulting in a marked reduction of dermal ridge counts.