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1.
Phys Rev Lett ; 129(24): 244802, 2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36563244

RESUMO

Creating, manipulating, and detecting coherent electrons is at the heart of future quantum microscopy and spectroscopy technologies. Leveraging and specifically altering the quantum features of an electron beam source at low temperatures can enhance its emission properties. Here, we describe electron field emission from a monocrystalline, superconducting niobium nanotip at a temperature of 5.9 K. The emitted electron energy spectrum reveals an ultranarrow distribution down to 16 meV due to tunable resonant tunneling field emission via localized band states at a nanoprotrusion's apex and a cutoff at the sharp low-temperature Fermi edge. This is an order of magnitude lower than for conventional field emission electron sources. The self-focusing geometry of the tip leads to emission in an angle of 3.7°, a reduced brightness of 3.8×10^{8} A/(m^{2} sr V), and a stability of hours at 4.1 nA beam current and 69 meV energy width. This source will decrease the impact of lens aberration and enable new modes in low-energy electron microscopy, electron energy loss spectroscopy, and high-resolution vibrational spectroscopy.

2.
East Asian Arch Psychiatry ; 29(2): 39-40, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31237244
3.
Ann Oncol ; 29(11): 2200-2207, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30202945

RESUMO

Background: Prognostic models are needed that reflect contemporary practice for men with metastatic castration-resistant prostate cancer (mCRPC). We sought to identify predictive and prognostic variables for overall survival (OS) in chemotherapy-naïve men with mCRPC treated with enzalutamide. Patients and methods: Patients from the PREVAIL trial database (enzalutamide versus placebo) were randomly split 2 : 1 into training (n = 1159) and testing (n = 550) sets. Using the training set, 23 predefined variables were analyzed and a multivariable model predicting OS was developed and validated in an independent testing set. Results: Patient characteristics and outcomes were well balanced between training and testing sets; median OS was 32.7 months in each. The final validated multivariable model included 11 independent prognostic variables. Median OS for low-, intermediate-, and high-risk groups (testing set) defined by prognostic risk tertiles were not yet reached (NYR) (95% CI NYR-NYR), 34.2 months (31.5-NYR), and 21.1 months (17.5-25.0), respectively. Hazard ratios (95% CI) for OS in the low- and intermediate-risk groups versus high-risk group were 0.20 (0.14-0.29) and 0.40 (0.30-0.53), respectively. Secondary outcomes of response and progression differed widely in model-defined risk groups. Enzalutamide improved outcomes in all prognostic risk groups. Conclusions: Our validated prognostic model incorporates variables routinely collected in chemotherapy-naïve men with mCRPC treated with enzalutamide, identifying subsets of patients with widely differing survival outcomes that provide useful information for external validation, patient care, and clinical trial design. Trial registration: ClinicalTrials.gov: NCT01212991.


Assuntos
Antagonistas de Androgênios/uso terapêutico , Antineoplásicos/uso terapêutico , Modelos Biológicos , Feniltioidantoína/análogos & derivados , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica , Benzamidas , Biomarcadores Tumorais/sangue , Progressão da Doença , Humanos , Masculino , Nitrilas , Feniltioidantoína/uso terapêutico , Prognóstico , Intervalo Livre de Progressão , Modelos de Riscos Proporcionais , Neoplasias de Próstata Resistentes à Castração/sangue , Neoplasias de Próstata Resistentes à Castração/mortalidade , Neoplasias de Próstata Resistentes à Castração/patologia
4.
Scanning ; 38(6): 842-856, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27302216

RESUMO

According to the statistic from World Health Organization (WHO), stroke is one of the major causes of death globally. Computed tomography (CT) scan is one of the main medical diagnosis system used for diagnosis of ischemic stroke. CT scan provides brain images in Digital Imaging and Communication in Medicine (DICOM) format. The presentation of CT brain images is mainly relied on the window setting (window center and window width), which converts an image from DICOM format into normal grayscale format. Nevertheless, the ordinary window parameter could not deliver a proper contrast on CT brain images for ischemic stroke detection. In this paper, a new proposed method namely gamma correction extreme-level eliminating with weighting distribution (GCELEWD) is implemented to improve the contrast on CT brain images. GCELEWD is capable of highlighting the hypodense region for diagnosis of ischemic stroke. The performance of this new proposed technique, GCELEWD, is compared with four of the existing contrast enhancement technique such as brightness preserving bi-histogram equalization (BBHE), dualistic sub-image histogram equalization (DSIHE), extreme-level eliminating histogram equalization (ELEHE), and adaptive gamma correction with weighting distribution (AGCWD). GCELEWD shows better visualization for ischemic stroke detection and higher values with image quality assessment (IQA) module. SCANNING 38:842-856, 2016. © 2016 Wiley Periodicals, Inc.


Assuntos
Infarto Encefálico/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Encéfalo/diagnóstico por imagem , Meios de Contraste , Humanos , Intensificação de Imagem Radiográfica
5.
J Thromb Haemost ; 14(1): 175-85, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26559391

RESUMO

UNLABELLED: ESSENTIALS: Molecular diagnostics has improved the differentiation of acute thrombotic microangiopathys (TMAs). Atypical hemolytic uremic syndrome may have features mimicking thrombotic thrombocytopenic purpura. We identified novel complement mutations and a high incidence of CD46, with favorable long term outcomes. Complement mutation analysis in TMA where the diagnosis is unclear and ADAMTS-13 activity is >10%. BACKGROUND: Differentiation of acute thrombotic microangiopathy (TMA) at presentation has historically been dependent on clinical parameters. Confirmation of thrombotic thrombocytopenic purpura (TTP) is increasingly reliant on demonstrating deficient ADAMTS-13 activity. The identification of alternative complement pathway abnormalities in atypical hemolytic uremic syndrome (aHUS), along with the proven efficacy of terminal complement inhibitors in treatment, has increased the need for rapid differentiation of TTP from aHUS. OBJECTIVES: We describe the clinical phenotype and nature of complement mutations in a cohort of aHUS patients referred as acute TMAs. PATIENTS/METHODS: Fourteen consecutive aHUS patients were screened for mutations in C3, CD46, CFH, CFI, and CFB, as well as factor H (FH) antibodies. All aHUS patients had ADAMTS-13 activity > 10%. RESULTS: Of 14 aHUS patients, 11 (79%) had platelet counts < 30 × 10(9) /L during the acute phase. Median presenting creatinine level was 295 µmol L(-1) , while five (36%) of 14 presented with a serum creatinine level < 200 µmol L(-1) . Alternative complement pathway mutations were detected in 9 (64%) of 14 patients, including CD46 mutations in five (36%) of 14 patients. Patients were identified with novel mutations in CFB and C3 that have not been previously reported. CONCLUSIONS: We demonstrate that diagnostic differentiation based on platelet count and renal function is insufficient to predict an underlying complement mutation in some aHUS cases. Specifically, we demonstrate a high frequency of functionally significant CD46 mutations which may mimic TTP. ADAMTS-13 activity > 10% in a patient with a TMA should necessitate genetic screening for complement abnormalities.


Assuntos
Proteína ADAMTS13/genética , Proteína ADAMTS13/metabolismo , Complemento C3/genética , Fator B do Complemento/genética , Microangiopatias Trombóticas/diagnóstico , Microangiopatias Trombóticas/genética , Doença Aguda , Adolescente , Adulto , Idoso , Síndrome Hemolítico-Urêmica Atípica/genética , Pré-Escolar , Análise Mutacional de DNA , Feminino , Humanos , Incidência , Lactente , Testes de Função Renal , Masculino , Proteína Cofatora de Membrana/genética , Pessoa de Meia-Idade , Mutação , Fenótipo , Contagem de Plaquetas , Púrpura Trombocitopênica Trombótica/diagnóstico , Púrpura Trombocitopênica Trombótica/genética , Estudos Retrospectivos , Adulto Jovem
6.
Intern Med J ; 44(4): 390-7, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24528892

RESUMO

BACKGROUND AND AIM: Community-acquired pneumonia (CAP) is a leading cause of mortality, morbidity and hospital admission, which places strain on our healthcare system. Procalcitonin (PCT) is a biomarker of bacterial infection which may help gauge the severity and prognosis of patients with CAP. In addition to clinical predictors, PCT may assist in decisions pertaining to timing of discharge from hospital and the discontinuation of antibiotics. This study aimed to determine the predictive role of PCT measurement in reducing hospital admissions, length of stay (LOS) and antibiotic (AB) usage in patients with CAP. METHODS: A prospective, single-blinded, externally controlled study of consenting adult patients admitted with CAP. PCT levels were obtained on day 1 and day 3 (when indicated). Investigator-evaluated clinical parameters, together with results of PCT levels, determined the timing of oral AB switch and discharge from hospital. This process was compared against standard practice, but was not actually implemented, for the purpose of this study. RESULTS: Sixty patients were included in the study. The mean age was 66.5 ± 21.2 years (56.3% male). The average Pneumonia Severity Index was 93 ± 39 (class IV) and the median CURB-65 was 2. The mean LOS for the standard practice cohort was 5.3 ± 4.6 days versus calculated LOS using the PCT guidance pathway of 3.7 ± 2.8 days. (P = 0.00006). CONCLUSIONS: Our study supports the hypothesis that by incorporation of PCT levels, hospital admission and LOS in patients with CAP can be reduced. A randomised prospective clinical trial is planned in an attempt to help confirm these findings.


Assuntos
Antibacterianos/uso terapêutico , Calcitonina/sangue , Infecções Comunitárias Adquiridas/sangue , Tomada de Decisões , Pneumonia/tratamento farmacológico , Precursores de Proteínas/sangue , Adulto , Idoso , Biomarcadores/sangue , Peptídeo Relacionado com Gene de Calcitonina , Infecções Comunitárias Adquiridas/tratamento farmacológico , Gerenciamento Clínico , Feminino , Glicoproteínas , Humanos , Tempo de Internação/tendências , Masculino , Pessoa de Meia-Idade , Pneumonia/sangue , Prognóstico , Estudos Prospectivos , Índice de Gravidade de Doença , Método Simples-Cego
9.
Acta Neurol Scand ; 113(6): 370-7, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16674603

RESUMO

OBJECTIVES: Although acupuncture therapy has demonstrated itself to be effective in several clinical areas, the underlying mechanisms of acupuncture in general and the analgesic effect in particular are, however, still not clearly delineated. We, therefore, have studied acupuncture analgesic effect through fMRI and proposed a hypothesis, based on the obtained result, which will enlighten the central role of the brain in acupuncture therapy. METHODS: The proposed model, termed as a broad sense hypothalamus-pituitary-adrenal (BS-HPA) axis, was based on our observed neuroimaging results. The model incorporates the stress-induced HPA axis model together with neuro-immune interaction including the cholinergic anti-inflammatory model. RESULTS: The obtained results coupled with accumulating evidence suggest that the central nervous system is essential for the processing of these effects via its modulation of the autonomic nervous system, neuroimmune system and hormonal regulation. CONCLUSIONS: Based on our fMRI study, it appears that understanding the effects of acupuncture within a neuroscience-based framework is vital. Further, we have proposed the broad sense-HPA axis hypothesis which incorporates the experimental results.


Assuntos
Terapia por Acupuntura , Sistema Nervoso Central/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Neuroimunomodulação/fisiologia , Sistemas Neurossecretores/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Animais , Sistema Nervoso Central/anatomia & histologia , Humanos , Sistema Hipotálamo-Hipofisário/anatomia & histologia , Inflamação/imunologia , Inflamação/fisiopatologia , Modelos Neurológicos , Sistema Hipófise-Suprarrenal/anatomia & histologia , Estresse Fisiológico/imunologia , Estresse Fisiológico/fisiopatologia
10.
J Environ Qual ; 30(3): 776-85, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11401267

RESUMO

Landfarming is used to treat petroleum hydrocarbon-contaminated soils and a variety of waste streams from industrial operations. Wastes are applied to a soil surface and indigenous soil microorganisms utilize the hydrocarbons in the applied waste as a carbon source for metabolism, thereby biodegrading the applied material. Concerns have been expressed that abiotic losses, such as volatilization, play a significant role in hydrocarbon reduction within the soil. To assist in better defining atmospheric releases of total hydrocarbons from landfarms treating petroleum hydrocarbons, a flux gradient micrometeorological approach was developed and integrated with a custom-built total hydrocarbon detector, and a novel air sampling system and averaging algorithm. The micrometeorological technique offers unobtrusive spatially averaged real-time continuous measurements, thereby providing a time history of emissions. This provides opportunities to investigate mechanisms controlling emissions and to evaluate landfarm management strategies. The versatility of the technique is illustrated through measurements performed at a remote landfarm used to treat diesel fuel-contaminated soil in northern Ontario and during routine operations at two active refinery landfarms in southwestern Ontario.


Assuntos
Agricultura , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Hidrocarbonetos/análise , Eliminação de Resíduos , Biodegradação Ambiental , Microbiologia do Solo , Tempo (Meteorologia)
11.
J Orthop Res ; 18(1): 109-15, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10716286

RESUMO

The incidence of meniscal tears in the chronically anterior cruciate ligament-deficient knee is increased, particularly in the medial meniscus because it performs an important function in limiting knee motion. We evaluated the role of the medial meniscus in stabilizing the anterior cruciate ligament-deficient knee and hypothesized that the resultant force in the meniscus is significantly elevated in the anterior cruciate ligament-deficient knee. To test this hypothesis, we employed a robotic/universal force-moment sensor testing system to determine the increase in the resultant force in the human medial meniscus in response to an anterior tibial load following transection of the anterior cruciate ligament. We also measured changes in the kinematics of the knee in multiple degrees of freedom following medial meniscectomy in the anterior cruciate ligament-deficient knee. In response to a 134-N anterior tibial load, the resultant force in the medial meniscus of the anterior cruciate ligament-deficient knee increased significantly compared with that in the meniscus of the intact knee; it increased by a minimum of 10.1 N (52%) at full knee extension to a maximum of 50.2 N (197%) at 60 degrees of flexion. Medial meniscectomy in the anterior cruciate ligament-deficient knee also caused a significant increase in anterior tibial translation in response to the anterior tibial load, ranging from an increase of 2.2 mm at full knee extension to 5.8 mm at 60 degrees of flexion. Conversely, coupled internal tibial rotation in response to the load decreased significantly, ranging from a decrease of 2.5 degrees at 15 degrees of knee flexion to 4.7 degrees at 60 degrees of flexion. Our data confirm the hypothesis that the resultant force in the medial meniscus is significantly greater in the anterior cruciate ligament-deficient knee than in the intact knee when the knee is subjected to anterior tibial loads. This indicates that the demand on the medial meniscus in resisting anterior tibial loads is increased in the anterior cruciate ligament-deficient knee compared with in the intact knee, suggesting a mechanism for the increased incidence of medial meniscal tears observed in chronically anterior cruciate ligament-deficient patients. The large changes in kinematics due to medial meniscectomy in the anterior cruciate ligament-deficient knee confirm the important role of the medial meniscus in controlling knee stability. These findings suggest that the reduction of resultant force in the meniscus may be a further motive for reconstructing the anterior cruciate ligament, with the goal of preserving meniscal integrity.


Assuntos
Ligamento Cruzado Anterior/fisiologia , Joelho/fisiologia , Meniscos Tibiais/fisiologia , Idoso , Idoso de 80 Anos ou mais , Humanos , Pessoa de Meia-Idade
12.
J Orthop Res ; 17(5): 769-76, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10569490

RESUMO

Our objective was to examine the function of the glenohumeral capsule and ligaments during application of an anterior-posterior load by directly measuring the in situ force distribution in these structures as well as the compliance of the joint. We hypothesized that interaction between different regions of the capsule due to its continuous nature results in a complex force distribution throughout the glenohumeral joint capsule. A robotic/universal force-moment sensor testing system was utilized to determine the force distribution in the glenohumeral capsule and ligaments of intact shoulder specimens and the joint kinematics resulting from the application of external loads at four abduction angles. Our results suggest that the glenohumeral capsule carries no force when the humeral head is centered in the glenoid with the humerus in anatomic rotation. However, once an anterior-posterior load is applied to the joint, the glenohumeral ligaments carry force (during anterior loading, the superior glenohumeral-coracohumeral ligaments carried 26+/-16 N at 0 degrees and the anterior band of the inferior glenohumeral ligament carried 30+/-21 N at 90 degrees). Therefore, the patient's ability to use the arm with the humerus in anatomic rotation should not be limited following repair procedures for shoulder instability because the repaired capsuloligamentous structures should not carry force during this motion. Separation of the capsule into its components revealed that forces are being transmitted between each region and that the glenohumeral ligaments do not act as traditional ligaments that carry a pure tensile force along their length. The interrelationship of the glenohumeral ligaments forms the biomechanical basis for the capsular shift procedure. The compliance of the joint under our loading conditions indicates that the passive properties of the capsule provide little resistance to motion of the humerus during 10 mm of anterior or posterior translation with anatomic humeral rotation. Finally, this knowledge also enhances the understanding of arm positioning relative to the portion of the glenohumeral capsule that limits translation during examination under anesthesia.


Assuntos
Úmero/fisiologia , Ligamentos Articulares/fisiologia , Articulação do Ombro/fisiologia , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Cadáver , Humanos , Pessoa de Meia-Idade , Robótica , Suporte de Carga
13.
J Shoulder Elbow Surg ; 8(4): 324-9, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10472004

RESUMO

The passive properties of the rotator cuff have been shown to provide some stability during anterior-posterior (AP) translation. However, the relative importance of the rotator cuff to joint stability remains unclear. The purpose of this study was to quantify the force contributions of the rotator cuff and of capsuloligamentous structures at the glenohumeral joint during AP loading. We hypothesized that the rotator cuff acts as a significant passive stabilizer of the glenohumeral joint and that its contribution to joint stability is comparable to the contribution made by the components of the glenohumeral capsule. A robotic/universal force-moment sensor testing system was used to determine both the multiple "degrees of freedom" joint motion and the in situ force carried by each soft tissue structure during application of an 89N AP load at 4 abduction angles. The percent contribution of the rotator cuff to the resisting force of the intact joint during AP loading was significantly greater during posterior loading (35% +/- 26%) than during anterior loading at 60 degrees of abduction (P < .05). The contribution of the rotator cuff (i.e., 29% +/- 16% at 30 degrees of abduction) was found to be significantly greater than the contributions of the capsule components during posterior loading at 30 degrees, 60 degrees, and 90 degrees of abduction (P < .05). However, no differences could be found between the respective contributions of the rotator cuff and the capsule components during anterior loading. The results support our hypothesis and suggest that passive tension in the rotator cuff plays a more significant role than other soft tissue structures in resisting posterior loads at the glenohumeral joint. The important role of the rotator cuff during posterior loading may be a result of the thin posterior joint capsule compared with the anterior capsule, which has several thickenings. This information increases our understanding of posterior stability at the glenohumeral joint during clinical laxity tests.


Assuntos
Manguito Rotador/fisiologia , Articulação do Ombro/fisiologia , Fenômenos Biomecânicos , Humanos , Técnicas In Vitro , Ligamentos Articulares/fisiologia , Movimento , Estresse Mecânico
14.
J Biomech Eng ; 121(3): 311-5, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10396697

RESUMO

The purpose of this study was to use an analytical approach to determine the forces in the glenohumeral ligaments during joint motion. Predictions from the analytical approach were validated by comparing them to experimental data. Using a geometric model, the lengths of the four glenohumeral ligaments were determined during anterior-posterior loading simulations and forward flexion-extension. The corresponding force in each structure was subsequently calculated based on length data via load-elongation curves obtained experimentally. During the anterior loading simulation at 0 deg of abduction, the superior glenohumeral ligament carried up to 71 N at the maximally translated position. At 90 deg of abduction, the anterior band of the inferior glenohumeral ligament had the highest force of 45 N during anterior loading. These results correlated well with those found in previous experimental studies. We believe that this validated analytical approach can be used to predict the forces in the glenohumeral ligaments during more complex joint motion as well as assist surgeons during shoulder repair procedures.


Assuntos
Ligamentos Articulares/fisiologia , Articulação do Ombro/fisiologia , Estresse Mecânico , Idoso , Fenômenos Biomecânicos , Cadáver , Simulação por Computador , Humanos , Úmero/anatomia & histologia , Úmero/fisiologia , Ligamentos Articulares/anatomia & histologia , Modelos Anatômicos , Rotação , Escápula/anatomia & histologia , Escápula/fisiologia , Articulação do Ombro/anatomia & histologia
15.
Osteoarthritis Cartilage ; 7(1): 110-21, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10367019

RESUMO

OBJECTIVE: The objective of this study was to study injury and reconstruction of the anterior cruciate ligament (ACL) and their effects on knee osteoarthritis. DESIGN: This manuscript discusses the function of knee ligaments, including the basic mechanical properties, the structural properties of their respective bone-ligament-bone complexes, as well as their time- and history-dependent viscoelastic characteristics. The in-situ forces in the ACL and its replacement grafts and knee kinematics before and after ACL reconstruction are also examined. RESULTS: A robotic/universal force-moment sensor (UFS) testing system has been developed which offers a unique method in determining the multiple-degree of freedom knee kinematics and in-situ forces in human cadaveric knees. Under a 110 N anterior tibial load we found at flexion angles of 15 degrees or lower, there was a significantly larger in-situ force in the PL bundle (approximately 75 N) of the ACL as compared to the AM bundle (approximately 35 N)(P < 0.05). We also found that a quadruple semitendinosus and gracilis tendon ACL graft may be better at fully restoring in-situ forces for the whole range of knee flexion when compared to a bone-patellar tendon-bone ACL graft. CONCLUSIONS: The robotic/UFS testing system allows us to determine knee kinematics and the in-situ forces in cadaveric knees in a non-invasive, non-contact manner. Additionally, the ability to reproduce kinematics during testing allows us to evaluate ACL and ACL graft function under external and simulated muscle loading conditions. Finally, we can also examine many of the variables of ACL reconstructions that affect knee kinematics and graft forces including graft tensioning, graft type, graft placement and tibial positioning during graft fixation.


Assuntos
Lesões do Ligamento Cruzado Anterior , Ligamento Cruzado Anterior/cirurgia , Osteoartrite do Joelho/etiologia , Ligamento Cruzado Anterior/fisiologia , Fenômenos Biomecânicos , Humanos , Articulação do Joelho/fisiologia , Ligamentos Articulares/fisiologia , Procedimentos Ortopédicos/métodos , Robótica/métodos , Tendões/transplante
16.
J Sci Med Sport ; 2(4): 283-97, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10710007

RESUMO

Knowledge of diarthrodial joint mechanics and specific function of the ligaments are needed in order to understand injury mechanisms, improve surgical procedures and design better post-surgical rehabilitation protocols. To facilitate these needs, a robotic/universal force-moment sensor (UFS) testing system was developed to measure joint kinematics in multiple degree-of-freedom and the in situ forces in the ligaments. When operated in the position control mode, the testing system applies a known load to the intact joint while the motion and force data are recorded. After transection of a ligament, the recorded motion for the intact joint is repeated and new force and moment data is recorded by the UFS. Since the robot reproduces the identical initial position as well as path of joint motion before and after a ligament is transected, the in situ force in the ligament is the difference between the two sets of force and moment data. In force control mode, a known force is applied to the intact knee while the kinematics are recorded. After ligament transection, the same force is applied while the changes in kinematics are again recorded. Testing in this mode is similar to a clinical examination that diagnoses ligament injury. To date, this testing system has been used for experimental studies that examine the anterior cruciate ligament & posterior cruciate ligament of the knee and ligaments of the shoulder. A three-dimensional finite element model has also been constructed based on CT/MRI scans of a knee specimen and validated using data obtained with the testing system. Once in vivo kinematics (such as during gait analysis or throwing activities) are available, the robotic/UFS testing system can be programmed to reproduce these joint kinematics on young human cadaveric specimens in order to generate a database for in situ forces in the ligaments, or Ligament replacement grafts. With appropriate computational models, the stresses and strains in these tissues in vivo can also be determined. Potential applications of this combined approach include pre-operative surgical planning, improvement of surgical procedures as well as development of appropriate post-operative rehabilitation protocols.


Assuntos
Articulação do Joelho/fisiologia , Ligamentos Articulares/fisiologia , Robótica , Articulação do Ombro/fisiologia , Fenômenos Biomecânicos , Cadáver , Desenho de Equipamento , Humanos , Traumatismos do Joelho/cirurgia , Articulação do Joelho/cirurgia , Ligamentos Articulares/lesões , Ligamentos Articulares/cirurgia , Modelos Biológicos , Amplitude de Movimento Articular/fisiologia , Lesões do Ombro , Articulação do Ombro/cirurgia , Estresse Mecânico , Torque , Suporte de Carga/fisiologia
17.
Proc Natl Acad Sci U S A ; 95(5): 2670-3, 1998 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-9482945

RESUMO

A preliminary study of the correlation between acupuncture points (acupoints) for the treatment of eye disorders suggested by ancient Oriental literature and the corresponding brain localization for vision described by Western medicine was performed by using functional MRI (fMRI). The vision-related acupoint (VA1) is located in the lateral aspect of the foot, and when acupuncture stimulation is performed there, activation of occipital lobes is seen by fMRI. Stimulation of the eye by directly using light results in similar activation in the occipital lobes by fMRI. The experiment was conducted by using conventional checkerboard 8-Hz light-flash stimulation of the eye and observation of the time-course data. This was followed by stimulation of the VA1 by using the same time-course paradigm as visual light stimulation. Results obtained with 12 volunteers yielded very clean data and very close correlations between visual and acupuncture stimulation. We have also stimulated nonacupoints 2 to 5 cm away from the vision-related acupoints on the foot as a control, and activation in the occipital lobes was not observed. The results obtained demonstrate the correlation between activation of specific areas of brain cortices and corresponding acupoint stimulation predicted by ancient acupuncture literature.


Assuntos
Pontos de Acupuntura , Mapeamento Encefálico , Córtex Cerebral/anatomia & histologia , Córtex Cerebral/fisiologia , Terapia por Acupuntura/métodos , Adulto , Feminino , Pé/inervação , Humanos , Imageamento por Ressonância Magnética , Masculino , Modelos Neurológicos , Lobo Occipital/anatomia & histologia , Lobo Occipital/fisiologia , Reprodutibilidade dos Testes
18.
Magn Reson Med ; 39(2): 331-5, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9469720

RESUMO

MR acoustic, or sound, noise due to gradient pulsing has been one of the problems in MRI, both in patient scanning as well as in many areas of psychiatric and neuroscience research, such as brain fMRI. Especially in brain fMRI, sound noise is one of the serious noise sources that obscures the small signals obtainable from the subtle changes occurring in oxygenation status in the cortex and blood capillaries. Therefore, we have studied the effects of acoustic, or sound, noise arising in fMR imaging of the auditory, motor, and visual cortices. The results show that the effects of acoustic noise on motor and visual responses are opposite. That is, for motor activity, there is an increased total motor activation, whereas for visual stimulation, the corresponding (visual) cortical activity is diminished substantially when the subject is exposed to a loud acoustic sound. Although the current observations are preliminary and require more experimental confirmation, it seems that the observed acoustic-noise effects on brain functions, such as in the motor and visual cortices, are new observations and could have significant consequences in data observation and interpretation in future fMRI studies.


Assuntos
Córtex Auditivo/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Córtex Motor/anatomia & histologia , Ruído/efeitos adversos , Córtex Visual/anatomia & histologia , Adulto , Córtex Auditivo/fisiologia , Humanos , Imageamento por Ressonância Magnética/instrumentação , Córtex Motor/fisiologia , Estimulação Física , Córtex Visual/fisiologia
19.
J Am Geriatr Soc ; 45(9): 1086-93, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9288016

RESUMO

OBJECTIVES: This study examined the importance that nursing home residents and nursing assistants ascribed to control and choice over everyday issues, the satisfaction of residents with their control and choice over these issues, and the nursing assistants' impressions of the extent to which control and choice exist for nursing home residents on everyday matters. DESIGN: Cross-sectional in-person interviews with a stratified representative sample of nursing home residents and nursing assistants using semi-structured interview protocols with both fixed-choice and open-ended questions. SETTING: A random sample of 25 nursing homes in the Twin Cities, MN area; a random sample of five nursing homes in North Little Rock, AR; all five nursing homes in Sante Fe, NM; and five purposively selected nursing homes in each of New York City and Los Angeles, CA. PARTICIPANTS: One hundred thirty-five cognitively intact residents, three from each facility, were selected and included the resident council chair, one randomly selected short-stay resident, and one randomly selected long-stay resident from each facility. Also participating were 134 nursing assistants (1 selected randomly from each shift from those employed at least two-thirds time and who had worked in the facility for at least 3 months). MEASUREMENTS: The most important measurements were ordinal-level ratings of the importance of choice and control for nursing home residents over 10 selected areas of everyday life; ordinal measures of residents' satisfaction with their choice and control over these areas; and nursing assistants' ratings of the extent to which they thought it possible for residents to achieve choice and control. Open-ended comments were also elicited. Also measured were demographic data, ADL status, frequency of trips away from the nursing home, frequency of receiving visitors, and (for nursing assistants) length of employment, wages, job satisfaction, and extent to which they knew the residents under their care. MAJOR RESULTS: Cognitively intact nursing home residents attach importance to choice and control over matters such as bedtime, rising time, food, roommates, care routines, use of money, use of the telephone, trips out of the nursing home, and initiating contact with a physician. Nursing assistants view such control as important to residents. Residents and staff differ significantly in the importance attached to particular items, with staff placing lower importance than residents on use of the telephone and personal expenditures and higher importance on control and choice over visitors and formal nursing home activities. Residents were not very satisfied with their control and choice, and nursing assistants viewed them as unlikely to experience control and choice. Nursing home, resident, and staff characteristics were not associated with the patterns of results. CONCLUSIONS: A self-defeating cycle has been identified where neither resident nor staff are optimistic about achieving more resident control and choice, which both groups perceive as desirable. To end this cycle, suggestions are offered for structuring the role of the nursing assistant, physician and nurse leadership, changes in nursing home routines and practices, and public policy changes.


Assuntos
Atividades Cotidianas , Comportamento de Escolha , Assistência Domiciliar , Pacientes Internados/psicologia , Controle Interno-Externo , Participação do Paciente , Satisfação do Paciente , Autonomia Pessoal , Idoso , Idoso de 80 Anos ou mais , Atitude do Pessoal de Saúde , Estudos Transversais , Feminino , Humanos , Tempo de Internação , Masculino , Assistentes de Enfermagem/psicologia , Inquéritos e Questionários
20.
Magn Reson Imaging ; 15(7): 815-22, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9309612

RESUMO

Acoustic or sound noise due to gradient pulsing has been one of the problems in magnetic resonance imaging (MRI), both in patient scanning as well as in many areas of psychiatric and neuroscience research such as functional MRI. Our recent observations in functional MRI for the visual and motor cortex show very different results with sound noise in comparison with the results obtained without sound noise. Although a number of ideas have been suggested in the literature about the possible elimination or reduction of sound noise, progress has been slow due to the basic role of gradient pulsing in MR imaging. Before we tackle the sound-noise-reduction problem, we believe that a systematic study of sound or acoustic noise behavior will provide important information for future endeavors in this area of research in MRI systems, in both commercial and research systems. Therefore, we report on some typical behavior of sound noise observed from MRI scanners and the analyses of their characteristics. Data are obtained both from a commercial MRI scanner (GE Signa 1.5-T EPI system) as well as a research-type MRI scanner (KAIS 2.0-T) developed at a university laboratory setting.


Assuntos
Imageamento por Ressonância Magnética , Ruído , Fenômenos Físicos , Física , Processamento de Sinais Assistido por Computador
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